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sbmathias
02-05-2010, 11:02 PM
I'd like to start afresh talking about Toyota's brake pedal problems. Papers and other media have recently started giving out illustrations of how the new shims will fix the problem. These illustrations show some kind of tongue-in-groove assemblies that can fit too tightly together, and the shims will move them apart slightly.
I can't figure out why these tongue-in-groove configurations are at all needed. Doesn't the pedal just provide a mechanical linkage to a master cylinder push rod? If so, what is wrong with a simple lever assembly?
I'd appreciate it if someone could enlighten me as to why a brake pedal needs to have such involved parts that are much more prone to problems. I'd go to the local Toyota dealer and ask, but they are probably pretty busy right now.

sbmathias
02-06-2010, 12:24 AM
Finally found an illustration like I've been seeing:

http://i219.photobucket.com/albums/cc300/sbmathias/toyotapedal.jpg

Carld
02-06-2010, 12:34 AM
Hmmm, and putting a spacer to limit the travel is supposed to loosen the Acme thread looking part at the top of the pedal pivot.

Ummhhhmm, when pigs fly.

tom in nh
02-06-2010, 12:36 AM
Which do you mean?
You state brakes in first post, but show accelerator pedal in second post.
Advise please...
Tom

Rookie machinist
02-06-2010, 12:50 AM
It looks as if the teeth have too tight a tolerance and stick when fully engauged. The shim looks like it is intended to prevent full tooth engaugement. Seems like a cheap fix. I would think a redesigned shoe/pedal assembly with more clearance would be a better solution.

Black_Moons
02-06-2010, 12:52 AM
its hard to keep track when the same company manages to fail at both pedals, the only major function of the car they havent managed to screw up is the steering.. at least, this year.

lakeside53
02-06-2010, 01:15 AM
In addition to any mechanical fix, killing throttle when the brake pedal is pressed (like cruise control) would be a smart move, but.. that would mean changing code/chips on the computers, and a lot more expensive to retrofit in comparison to the above. A error could also be generated/logged if the throttle is "stuck"... Could have saved a couple of lives.

Black_Moons
02-06-2010, 01:46 AM
Hmmm, it looks like to me when the pedal is fully depressed, it causes the shoe to pivot forward at the top and the teeth to lock togethor... possabley reguardless of 'moisture' (though im sure humidity causes the plastic to expand past some frivious tollerances that where made to insure this could not happen if the world stayed at exactly 20c and 50% RH), and the shim just prevents the shoe from pivoting forward as much.. Possabley still allowing the origional fault if the shim falls out of place, or the plastic deforms with time or flows. (Bet they just glue the shim in place or something)

ckelloug
02-06-2010, 01:59 AM
Toyota may be blowing smoke about this problem. There are a few embedded software columnists who think the shim fix might be grasping at straws when the real error is in the software that controls the throttle. It is my understanding that these toyotas with the accelerator problem are drive-by-wire: the pedal is not a mechanical linkage to the engine at all but a sensor input into the ECU. Only time will tell whether the sudden accelerations go away with the shims. It will be a bad day if it turns out that the problem is actually software.

--Cameron

Doc Nickel
02-06-2010, 02:54 AM
its hard to keep track when the same company manages to fail at both pedals, the only major function of the car they havent managed to screw up is the steering.. at least, this year.

-Um, no. The issue with the car has been a possible sticky throttle pedal, causing the car to accellerate out of control. As in the accellerator pedal doesn't snap back up as it should when released.

What we were talking about here, was the fact that, in one of the accidents, the driver, who was unused to the car, was apparently unable to shut the engine off (apparently due to the "push to start" button as opposed to a conventional ignition key) nor shift it into neutral (again, supposedly due to his unfamiliarity with the car's "sport" shifter gate, which probably had a mild interlock so you didn't snap the thing into neutral instead of just shifting) which in turn led to him burning the brakes out and subsequently crashing.

The "official" issue was the sticky acellerator. The issue we were arguing about was the brakes.

Doc.

winchman
02-06-2010, 04:25 AM
That's the most uninformative technical illustration I've seen in a long time.

My questions are:

Is the pedal shown in the idle or WOT position?

What holds the shoe in place?

How exactly does moving things closer together decrease the friction?

What is the reinforcement bar reinforcing?


In the side view, it appears the shim will keep the pedal from going down all the way. That should ease the load on the brakes when the pedal sticks. :D

SpyGuy
02-06-2010, 04:50 AM
That's the most uninformative technical illustration I've seen in a long time.

My questions are:

Is the pedal shown in the idle or WOT position?

What holds the shoe in place?

How exactly does moving things closer together decrease the friction?

What is the reinforcement bar reinforcing?

You must realize that this is not a true engineering diagram. I suspect this "technical illustration" wasn't even produced by Toyota. Media companies (they ain't "news" organizations anymore) are notorious for not having a clue about hard sciences or engineering, and often their simplified illustrations (for the likewise undereducated public) are very lacking in both detail and accuracy.

So of course they are not going to show how the shoe is held in place, nor how the "reinforcement bar" (i.e., I'm sure a more accurate name for this is "shim") will be held in place. But it appears to me that the shim is causing the shoe to pivot (rotate counterclockwise) so that as the bottom is moved by the shim toward the pedal, the top of the shoe moves away from the pedal friction teeth.

In the side view illustration, the pedal is signaling WOT. Apparently that is also when you have full engagement of the teeth between the pedal assembly and the shoe. Realize that since there is no mechanical linkage between the pedal and a throttle plate, then there must be a way of producing friction for driver feedback (i.e., the feel in the foot). That is the purpose of the "shoe". Imagine how disconcerting it would be to try to operate an accelerator pedal that has little friction and is simply a spring loaded lever.

SpyGuy
02-06-2010, 04:54 AM
In addition to any mechanical fix, killing throttle when the brake pedal is pressed (like cruise control) would be a smart move, but.. that would mean changing code/chips on the computers, and a lot more expensive to retrofit in comparison to the above. A error could also be generated/logged if the throttle is "stuck"... Could have saved a couple of lives.

How many lives have been lost due to this problem? As far as i know, the only fatalities that POSSIBLY involved this pedal assembly were from the wreck in San Diego involving the Highway Patrolman. And we still don't know the exact cause of that mishap, with an improper floormat being the most probable causal factor at this time.

SpyGuy
02-06-2010, 05:19 AM
Looking at the bigger picture, why is Toyota being singled out for recall, halted sales, and factory shutdowns? Consider that CTS, the company "that supplies some Toyota models with the gas pedal in question, also supplies the same gas pedal to Honda, Ford, GM and Chrysler." And that other cars -- including cars made by GM and Chrysler -- have also had similar sudden unintended acceleration complaints filed with the National Highway Traffic Safety Administration, yet have not been subject to government-mandated recall.

Perhaps the Obama administration and the UAW have it in for Toyota, which is both very successful and non-union. Since Obama is now a co-owner of both GM and Chrysler, what better way to cut out the competition than to use the unlimited power of the federal government to attack your chief business rival? Yet another reason why socialism fails.

Read the article here (http://www.wnd.com/index.php?pageId=123686).

EVguru
02-06-2010, 05:32 AM
In addition to any mechanical fix, killing throttle when the brake pedal is pressed (like cruise control) would be a smart move, but.. that would mean changing code/chips on the computers, and a lot more expensive to retrofit in comparison to the above. A error could also be generated/logged if the throttle is "stuck"... Could have saved a couple of lives.

Cutting the throttle if the brakes are applied has been tried.

Customer acceptance was pretty much zero and it didn't go into production.

Many drivers of automatics rest their left foot quite heavily on the pedal. One of the old racing brake compounds was actually developed by Ford for just this reason.

SpyGuy
02-06-2010, 05:47 AM
Many drivers of automatics rest their left foot quite heavily on the pedal. One of the old racing brake compounds was actually developed by Ford for just this reason.

And breaking stupid people of that bad habit would be the ONLY good reason for having the brake kill the throttle. :cool:

Weston Bye
02-06-2010, 06:31 AM
Finally found an illustration like I've been seeing:

http://i219.photobucket.com/albums/cc300/sbmathias/toyotapedal.jpg

The design looks as though the designer built in some friction into the pedal to approximate the friction inherent in a mechanically linked accelerator, so the driver could "feel" the pedal. Also, minor position changes from vibration are dampened.

If the rendition is approximately accurate, it appears that the basic design can be questioned. Given limited space for a friction device, the designer "folded" up the surface area, creating the equivalent of multiple taper engagements.

Referring to Machinery's Handbook, "The term "self-holding" is used to distinguish relatively small tapers from the larger or self-releasing type."

Machinery's goes on to describe and diagram the various standard tapers, the point being that the the smaller the included angle of the taper, the more likely it is to be self-locking. Machinery's deals with taper applications in steel; machine spindles and tool shanks, etc. Plastics operate under a different set of parameters; the acceptable included angles for self-holding vs. self releasing may be different for different formulations. Indeed, the parameters may change with moisture content. Add dust as another factor.

The addition of the shim prevents the full engagement of the originally designed friction surfaces. The pedal will be more responsive. The negative effect of this is that any little twitch of the drivers foot will be more likely to result in a throttle position change. Rough roads may result in erratic vehicle speed, which might increase driver fatigue due to consious or unconsious correcting of pedal position.

nheng
02-06-2010, 08:23 AM
If those teeth are, in fact, used to simulate the mechanical feedback to the user of a conventional pedal, I will never touch another Toyota. What a p~ss poor design.

It might also be a good idea to allow all Toyota's to pass :)

If this has anything to do with damaging the competition as one poster suggests (and has certainly crossed my mind), then we are truly in big trouble.

I read the other day about electric motors in the Chevy Cobalt steering system instead of hydraulics. They apparently are having problems also. Is it true that the system uses electric motors for power assist?

Den

Evan
02-06-2010, 08:55 AM
The addition of the shim prevents the full engagement of the originally designed friction surfaces. The pedal will be more responsive. The negative effect of this is that any little twitch of the drivers foot will be more likely to result in a throttle position change. Rough roads may result in erratic vehicle speed, which might increase driver fatigue due to consious or unconsious correcting of pedal position.


Weston has it correct. The assembly is intended to provide friction that prevents the pedal from moving freely. It is there to create some "stiction" in the pedal so that when you press it to a particular position it will hold that position while supporting the weight of your foot. I have had many new vehicles over the years when I worked for Xerox and some were absolutely horrible in this respect. If the pedal is too free moving it requires you to hold your foot at the needed position by pure muscle tension and is extremely tiring on a long drive.

What the drawing does not show is most important to understanding the problem. How does the return spring mechanism work? Is it progressive as the pedal is pushed further down or does it exert the same return force at all positions? Ideally the return spring should be two stage just as it is with a two or four barrel carb. To a particular point the pedal should support foot weight but beyond that point the return spring should become much stronger requiring a concerted effort to hold wide open throttle.

Remember, this is a 300 hp engine in the ES350. Nobody will be driving it legally for any length of time at WOT. The fix as shown will make the pedal literally painful to hold in position for a long drive and is not a solution that will be acceptable to drivers. A proper fix would be a spring added that increases pedal return effort considerably at some point during down travel. The amount should well exceed the amount of force that an average driver exerts by resting their foot on the pedal.

Such a design would probably also alleviate the floor mat issue.

SpyGuy
02-06-2010, 09:13 AM
If those teeth are, in fact, used to simulate the mechanical feedback to the user of a conventional pedal, I will never touch another Toyota. What a p~ss poor design.

As noted in one of my earlier posts, the "problematic" pedal assembly** is produced (and probably was designed) by an American company and has been sold to Honda, Ford, GM and Chrysler. So I guess you'll never want to touch any of those vehicles too. And isn't it VERY INTERESTING that none of those other manufacturers -- using the EXACT same pedal assembly -- are not being forced to recall any vehicles or stop sales? As the Left loves to say... QUESTION AUTHORITY.

** I say "problematic" with quotes because it has yet to be definitively proven that there is in fact a problem with the design. Just because Toyota is going ahead with a "fix", that doesn't mean the original design was faulty. Obviously Toyota is in a position now where it MUST do something, even if just for show.

With all the millions vehicles on the road using this pedal assembly (including all the manufacturers that are using this design), why is the problem so rare if the design is truly faulty? Note the following:

Only "52 [sudden unintended acceleration] complaints out of 1.8 million Toyota/Lexus vehicles sold in the U.S. in 2008". That's less than 0.003% of Toyota vehicles sold in 2008. Is that statistically significant enough to shut down Toyota (and ONLY Toyota)? For all we know, many of those 52 complaints could have been people who caused a rear-end collision by tailgating or whatever, and then just said, "Gee officer, I don't know how it happened.... it just took off by itself!" Those kinds of "sudden acceleration" events HAVE been occurring for as long as people have been driving.

As the propaganda flows, don't forget to think. (Note that rational thinking is something the government-run schools have been stymieing for decades now. See more big government connections here?)

SpyGuy
02-06-2010, 09:20 AM
If the rendition is approximately accurate, it appears that the basic design can be questioned.

That's a huge "IF". I wouldn't go to too much trouble trying to critically analyze the design based solely on that illustration. We really don't know from this image how much taper is in the tooth design, nor how much tooth engagement there is (nor how much will remain after the "fix").

But do you really think the company** that designed this used a self-holding taper?

** I strongly doubt that Toyota designed this pedal assembly as it has been reportedly sold to a number of other manufacturers.

SpyGuy
02-06-2010, 09:24 AM
The fix as shown will make the pedal literally painful to hold in position for a long drive and is not a solution that will be acceptable to drivers.

Again assuming the fix is as shown and that the change in engagement is significant (as shown). I think it's safer to assume that the change in tooth engagement has been wildly exaggerated in that illustration.

Weston Bye
02-06-2010, 09:35 AM
I read the other day about electric motors in the Chevy Cobaly steering system instead of hydraulics. They apparently are having problems also. Is it true that the system uses electric motors for power assist?

Den

Could be true. This is the first I've hears about problems. My HHR has electrical steering assist. Wonder what safeties have been built into that system? Better or worse than hydraulics? Of course, hydraulics have stood the test of time.

Carld
02-06-2010, 09:37 AM
Here in Louisville Ky a man was sitting at a T intersection with his foot on the brake. In front of his was a very deep drainage ditch with steep sides. The car suddenly went WOT with his foot on the brake and the car ran forward over the edge and flipped upside down in the water. He almost drowned before they got him out and he had spinal injuries. He has recently regained the use of his legs.

I believe there was a passenger in the car as a witness and a lawyer is already on the case and they are inspecting the car for the cause.

I still don't believe the pedal fix will do anything. I believe the problem is in the on board computer and the electronics.

Someone said they tried the brake pedal interlock and have it up because of brake riders, well that would get those brake riders off the brake or change cars and I am 200% for that.

Carld
02-06-2010, 09:47 AM
I was just reading the Couier-Journal paper and there is an article about a woman that was in for an oil change and the dealer said they could do the pedal repair then so they did it.

It took ten minutes to install the part then they did a computer diagnostic test and then a road test. That sounds awfully fast to remove the throttle pedal, install the shim and reinstall the pedal.

How do we know they don't also install a change in the program as a fix and the shim is a sham?

Weston Bye
02-06-2010, 09:47 AM
That's a huge "IF". I wouldn't go to too much trouble trying to critically analyze the design based solely on that illustration. We really don't know from this image how much taper is in the tooth design, nor how much tooth engagement there is (nor how much will remain after the "fix").

But do you really think the company** that designed this used a self-holding taper?
** I strongly doubt that Toyota designed this pedal assembly as it has been reportedly sold to a number of other manufacturers.

Being in the business, I am absolutely certain that they did not intend to use a self-holding taper. Whether Toyota designed the pedal or not, they are required to perform design reviews and still have design responsibility. Whatever failure occurred here was not the fault of a single individual designer or engineer, but a team and manufacturing system.

Weston Bye
02-06-2010, 09:53 AM
How do we know they don't also install a change in the program as a fix and the shim is a sham?

I share your skepticism. There may be multiple problems that are now coming to light.

SpyGuy
02-06-2010, 09:58 AM
The fix as shown will make the pedal literally painful to hold in position for a long drive and is not a solution that will be acceptable to drivers.

Actually, the fix as shown will not even go into effect unless the accelerator pressed to the WOT position. Therefore, there will be no change in before/after driveability nor in operator leg fatigue.

In fact, the "fix" may have more to do with limiting the WOT position of the accelerator (and less to do with altering friction teeth engagement beyond that achieved by limiting the WOT position).

Willy
02-06-2010, 09:59 AM
How many lives have been lost due to this problem? As far as i know, the only fatalities that POSSIBLY involved this pedal assembly were from the wreck in San Diego involving the Highway Patrolman. And we still don't know the exact cause of that mishap, with an improper floormat being the most probable causal factor at this time.

Nearly 8 million vehicles recalled world wide, for one incident, I don't think so.
Out of the 2 million US vehicles there have been 389 complaints to NHTSA regarding unwanted acceleration. Up to 19 of those cases resulted in death.
A very small percentage to be sure, but still a serious issue exists.

nheng
02-06-2010, 10:03 AM
Spyguy, you are absolutely correct and this further questions the accuracy of the "illustration". What may be more likely is that the shim is at the top, pushing and effectively rotating the "shoe" outward to a less engaged position. This would make sense but is still a dumb design if it was intended to wedge the two halves together for a sense of torque / pedal pressure. Den

SpyGuy
02-06-2010, 10:13 AM
Here in Louisville Ky a man was sitting at a T intersection with his foot on the brake. In front of his was a very deep drainage ditch with steep sides. The car suddenly went WOT with his foot on the brake and the car ran forward over the edge and flipped upside down in the water. He almost drowned before they got him out and he had spinal injuries. He has recently regained the use of his legs.

I believe there was a passenger in the car as a witness and a lawyer is already on the case and they are inspecting the car for the cause.

While I disagree with Evan's contention (from the other thread) that brakes alone can stop any WOT acceleration condition while at speed, I share his skepticism that a sudden unintended WOT can move a stopped car that has the brakes fully applied. The vehicle has no momentum, and inertia as well as the static friction of the brakes are working against the moving of the vehicle. In such a situation, the torque converter will simply froth the ATF.

I don't see how a passenger can be considered a reliable witness in such a case. Besides the bias one would expect given that the passenger was a victim of the mishap (and stands to profit handsomely from any tort action), do you really think the passenger was staring at the driver's feet before the car took off from the stop? Unlikely. So how do we know the driver's foot didn't slip off the brake and onto the accelerator?

A lawyer is already on the case??? :eek: Say it ain't so!!!

SpyGuy
02-06-2010, 10:29 AM
Carld's story reminded me of this:

Last October [2004] the rescue squads of the town of Old Saybrook, Ct., were hailed as heroes for their work in attempting to save Barbara Connors, 75, of Medfield, Mass., from a Ford Explorer that had plunged into the Connecticut River. Connors’ son-in-law, who had been at the wheel and who managed to escape from the vehicle on his own, later told police he accidentally hit the SUV’s accelerator, propelling it through a chain-link fence and into the water below. But now Connors is suing a long list of officials of the town (population 1,962) on the grounds that they should have maintained or funded a specially dedicated and equipped dive rescue team; had they done so, she would have been rescued from the submerged vehicle in less than the 29 minutes it actually took, avoiding serious injury. Through her attorney, Robert Reardon Jr. of New London, she’s also suing the son-in-law. “‘I find it extraordinary the town is being sued in these circumstances,’ First Selectman Mike Pace, one of the defendants, said at Thursday’s selectmen’s meeting.” (Claudia Van Nes, “Town Sued Over River Rescue”, Hartford Courant, Aug. 5; Walt Platteborze, “Woman ‘critical’ after being pulled from submerged SUV”, New Haven Register, Oct. 15, 2004). (http://overlawyered.com/2005/08/dept-of-gratitude/)

At least the son-in-law was honest about his mistake. But that still didn't stop some bottom-feeding lawyer from suing everyone imaginable.

By the way, they were in a parking area when this occurred. And from another article on this particular case: "The suit also charges the fence should have been stronger, the Point patrolled at lunchtime by police, and more signs warning of "unsafe conditions" posted."

I'm sure the warning signs, had they been posted, would have prevented the son-in-law from accidentally hitting the accelerator. And too bad the curb and chain link fence between the parking lot and the river weren't designed to stop high-speed cars!

winchman
02-06-2010, 10:32 AM
Bad news: The Prius is one of the cars with electric power steering. See:

http://www.aa1car.com/library/steering_power_electric.htm

You'd expect that, since you can drive it with the engine off.

On the "brake-to-idle" issue, I thought it took significant brake pressure to over-ride the throttle input on cars that have it. I don't think it's just a switch like that used to disengage the speed control or brake lights.

It's on Nissans and a lot of European cars, so somebody must have figured out how to make it work for dummies who ride the pedal.

J Tiers
02-06-2010, 10:32 AM
-Um, no. The issue with the car has been a possible sticky throttle pedal, causing the car to accellerate out of control. As in the accellerator pedal doesn't snap back up as it should when released.




-Um, YES..................

Those models for throttle, Prius for brakes...... only Toyota hasn't quite admitted the brake issue exactly....... at least they have fixed it definitively on new production, but are dragging their feet about already-produced cars, refusing a recall.

To be fair, reports either have it as a slight delay in braking, OR as a "brake failure"...... it may be minor.

GM has brake failure on ALL models with ABS, and Ford does also. I have rolled into intersections with the brakes on full..... no braking (Chevy S10). A co-worker rear-ended a tiny GEO with his Lincoln Town Car when the ABS "let go".

Ironically, the damage to the Town Car was $2500, the Geo had NO damage.

Both Ford, GM, and the NHTSA are ignoring the brake issue, and the dealers say they can't touch it because it isn't 'throwing codes"....

Maybe Toyota IS being targeted....... But Toyota is the one with the fatal accidents.

Apparently it generally takes a certain number of people killed before the NHTSA wakes up and decides to think about commencing to begin to start a preliminary exploratory investigation.

mochinist
02-06-2010, 10:47 AM
Apparently it generally takes a certain number of people killed before the NHTSA wakes up and decides to think about commencing to begin to start a preliminary exploratory investigation.Reminded me of a scene from the movie "Fight Club"

copy/paste
Narrator (http://www.imdb.com/name/nm0001570/): A new car built by my company leaves somewhere traveling at 60 mph. The rear differential locks up. The car crashes and burns with everyone trapped inside. Now, should we initiate a recall? Take the number of vehicles in the field, A, multiply by the probable rate of failure, B, multiply by the average out-of-court settlement, C. A times B times C equals X. If X is less than the cost of a recall, we don't do one.
Business woman on plane (http://www.imdb.com/name/nm0236148/): Are there a lot of these kinds of accidents?
Narrator (http://www.imdb.com/name/nm0001570/): You wouldn't believe.
Business woman on plane (http://www.imdb.com/name/nm0236148/): Which car company do you work for?
Narrator (http://www.imdb.com/name/nm0001570/): A major one.

steve45
02-06-2010, 10:51 AM
I don't believe in the 'sticky pedal' problem. I also think it must be software related. It happened to a friend of mine recently while he was backing into his parking space inside a parking garage. When he bumped the tire stop, it suddenly went to full throttle. He hit the brake, but the tires continued to spin and drove the vehicle over the tire stop into the wall behind him.

In another incident, a friend of a friend was involved in a fatal accident with a Lexus about 4 years ago. Again, this happened while parking. The driver bumped a tire stop at a convenience store and the vehicle just took off. In just a matter of a second or two, it jumped the tire stop, jumped the curb, then ran through the front wall of the store and killed another customer. Investigators blamed the driver for stepping on the wrong pedal. The driver filed a lawsuit against Toyota that is still not settled.

One thing to keep in mind with power brakes it that most power brake systems are operated by engine vacuum. When the throttle is wide open, there is very little power assist.

Ed P
02-06-2010, 10:53 AM
-Um, no. The issue with the car has been a possible sticky throttle pedal, causing the car to accellerate out of control. As in the accellerator pedal doesn't snap back up as it should when released.

How does a sticky throttle cause the car to accelerate out of control? I noticed some are talking as if they were one and the same but I thought "unintended acceleration" and sticky throttle were two different issues.

Ed P

Willy
02-06-2010, 10:55 AM
I don't see how a passenger can be considered a reliable witness in such a case. Besides the bias one would expect given that the passenger was a victim of the mishap (and stands to profit handsomely from any tort action), do you really think the passenger was staring at the driver's feet before the car took off from the stop?

Spyguy, tell me you're not serious.
It sounds like you followed the other thread as well, so after listening to the frantic 911 call, do you honestly think the caller was thinking..."gee I'm going to sue the pants off of my brother in law if I get out out of here"? They were praying for their lives for crying out load...not tort actions!
Seems you are searching for a lot of conspiracies here, first Obama, and now the brother in law.

Ed P
02-06-2010, 11:08 AM
I don't believe in the 'sticky pedal' problem. I also think it must be software related. It happened to a friend of mine recently while he was backing into his parking space inside a parking garage. When he bumped the tire stop, it suddenly went to full throttle. He hit the brake, but the tires continued to spin and drove the vehicle over the tire stop into the wall behind him.

If you look into it you will find that the majority if not all of the cars recalled by Toyota are NOT drive by wire. They have a simple cable between the pedal and throttle, no software involved.
The accident you describe is not unusual and has been occuring with all cars no matter who the manufacturer and the various investigations done by different agencies around the world have all agreed it's "pedal misapplication" despite what the drivers claim.

Ed P

J Tiers
02-06-2010, 11:12 AM
The stepping on wrong pedal thing......

That doesn't really ring true to me...... after driving for many years, you get natural reactions, you don't have to make a decision to even step on a pedal, you want to stop, and your feet hit the pedals without further thought.

it is like playing a violin.... where there are no frets, fingers go "where the note is" automatically.

I suppose it is "possible" to step on the wrong pedal, I mean they are there, and so are your feet........ But the automatic reaction "sends" your feet to the right place, and it is hard to avoid..... I find that if I see brake lights right in front of me, I don't think, I "find" that my feet are on teh brake and clutch without any thought.

I am willing to bet that half of the cases, EVEN OLD PEOPLE, are not cases of "getting confused and stepping on the wrong pedal" at all. I think many are simply a good way of closing the case with an identified "culprit". A "culprit" who has no way of extricating themselves..... after all "all old people are kinda batty, and so you see one and you just KNOW they are easy to confuse"...... it's easy, simple, and you get to take their license away and "show you are doing something" :rolleyes:

In most cases there is no good way to "prove" which pedal a foot was on, after all. Not unless you find the brake pedal imprinted on the shoe of the driver's corpse.....

Ed P
02-06-2010, 11:13 AM
It's interesting that the feds have decreed that September 2012 all cars will have "Event Data Recorders". I predict it will show what we already know, that people are very creative liars.

Ed P

Evan
02-06-2010, 11:13 AM
I don't think the computer has anything to do with this. The only vehicles that exhibit the problem are those with pedals manufactured in the USA by CTS Corp. Cars with pedals designed and made in the US are the ones affected. The Japanese designed and made pedals by Denso are not affected. That is not consistent with a computer problem.

Here are pictures illustrating the exact differences and why one fails and the other does not.

http://ixian.ca/pics7/pedal2.jpg

MORE HERE: http://www.thetruthaboutcars.com/why-toyota-must-replace-flawed-cts-gas-pedal-with-superior-denso-pedal/

Ed P
02-06-2010, 11:25 AM
If those teeth are, in fact, used to simulate the mechanical feedback to the user of a conventional pedal, I will never touch another Toyota. What a p~ss poor design.

It might also be a good idea to allow all Toyota's to pass :)

Den

An interesting conclusion considering the faulty part that you are so critical of is AMERICAN made and has been installed in a large number of American cars.

Ed P

Willy
02-06-2010, 11:25 AM
Evan why then is Toyota recalling 8 million cras worldwide?
Surely Toyota has better things to do. CTS isn't supplying Toyota on all continents.

Willy
02-06-2010, 11:35 AM
The stepping on wrong pedal thing......

That doesn't really ring true to me.....

I don't know JT, there's a whole lot of confusion and stupidity out there.
Hardly a week goes by that I don't read, or see on the news a story about another errant driver plowing into a store.

http://www.youtube.com/watch?v=Rlqq22iRCYk&feature=related

See the related videos on the side bar as well.

Or are you inferring that this is all related to bad design work slipping through, from all manufacturers?
I hate to say it but I think the big guy upstairs should initiate a recall as well.:D

Evan
02-06-2010, 11:40 AM
Evan why then is Toyota recalling 8 million cras worldwide?


Because they also have a floormat problem.

J Tiers
02-06-2010, 11:41 AM
I don't think the computer has anything to do with this. The only vehicles that exhibit the problem are those with pedals manufactured in the USA by CTS Corp. Cars with pedals designed and made in the US are the ones affected.

The pedals are apparently made in CANADA............ by a CTS division there..... at least as reported by NPR.

The design is apparently Toyota's, and passed the Toyota qualification and QC. Also reported by NPR.

Note that NPR would be happy to "blame america first" if they got the chance..... so they probably checked their facts


Willy......

No doubt people DO step on wrong pedals...... but as I said, I suspect that numbers of cases, such as the Lexus case mentioned above, are not that problem.

When you are actually in the seat and driving, your feet 'go to" the right pedals automatically....... How often do you put in the clutch with your right foot (in US) or push on gas with left foot?

Now, if you are trying to twist around and get something out of the back, while your foot is on the brake and car is idling and not in neutral, sure..... but that is really not a "stepped on wrong pedal" thing, but a "tried to do too many things at once" issue.

A.K. Boomer
02-06-2010, 11:43 AM
If the rendition is approximately accurate, it appears that the basic design can be questioned. Given limited space for a friction device, the designer "folded" up the surface area, creating the equivalent of multiple taper engagements.

Referring to Machinery's Handbook, "The term "self-holding" is used to distinguish relatively small tapers from the larger or self-releasing type."




Im In total agreement With Weston, and in fact if the diagram that is presented is true I really cant believe my eye's, The unit is lacking in both book smart engineering and esp. lacking in anyone with even an inkling of field experience,
Im a big fan of Toyota - and I wanted to wait and see the design flaw -- if this same unit is on other brands let it all come out,
This design is an absolute NO-NO, They don't show where the pivoting area is for the yellow piece is but depending on that it could actually be a good illustration for how to create a ONE WAY JAM APPARATUS!

You Do Not do this ------ To simply install a heavier gauge throttle return spring IS BAD MEDICINE!

Depending on the compatibility of the plastics being used -- the wear patterns they create on each other, how they hold up to age (self lubricating plastics drying out)
A system like this could have a 100% failure rate over time and depending on the hinge point could jam to the point where it WILL BREAK PARTS FIRST BEFORE IT RETURNS...

Look at the leverage ratio's of the taper's, if you allow these two surfaces to contact each other for a throttle operation its insane...

If you actually then go and put the load piece in a direction that can cause it to self bind on the return stroke then youv just built a death apparatus.

You want to create a safe drag mechanism throw a smooth polished SS disc off to one side and spring load some felt washers into it with some viscous coupling grease, besides expecting a little return delay variance in extreme temperature's you at least have something that you can count on always coming back to you...

Crazy...

Edit; Heads should roll, the so called "engineers" first to all the people who approved this piece of crap, then heads should roll again, for even considering to "re-use" this poor design by just adding a shim,
This is very sad, for as far as personal pride and quality goes the typical Japanese auto worker take's their job extremely serious and now they will pay the price with layoffs and such all because of some higher up hillbillys making idiotic decisions.

Evan
02-06-2010, 11:56 AM
The pedals are apparently made in CANADA............ by a CTS division there..... at least as reported by NPR.


Funny thing about that is the Denso pedals that don't fail are also made in Canada.

JCHannum
02-06-2010, 12:06 PM
It might be interesting to see what CTS has to say;

http://www.ctscorp.com/publications/press_releases/nr100127.htm

CTS pedals are not used in any Lexus or PRIUS models, which are also experiencing problems;

http://www.ctscorp.com/publications/press_releases/nr100203.htm

http://www.ctscorp.com/

I don't think Toyota has yet addressed the entire problem or series of problems that exist. It began with a floormat and has progressed to blaming the CTS pedal. EMI has also been mentioned in some reports. That may or may not be involved, but I think much more than a simple friction problem is involved.

J Tiers
02-06-2010, 12:09 PM
Also, I note from the article that "TOYOTA" changed the friction material in the CTS pedal......

If that does not display the Toyota direct design input into the "CTS" pedal, I don't know what does.

CTS may MAKE the pedal, but Toyota approved, accepted, and has used that design. They very well may have designed it, but they sure as heck analyzed it and approved it.*

No amount of joyful trumpeting that "its really an American company that screwed up Toyota" will change the basic fact that Toyota is the common factor here.....

As far as an inherently flawed design, it depends entirely on the fit. If the parts are made to jam, that's one thing, but showing little red spots on a drawing is not the same thing as the part really doing that. It may, or it may not have severe interference at the indicated spots. One would have to check the SPC results on teh width etc of teh parts to see if they do interfere so severely, and if the plastic warps or shrinks in such a way as to cause a jam.

*"The products we supply to Toyota, including the pedals covered by the recent recall, have been manufactured to Toyota’s design specifications."

That suggests that Toyota supplied design specs in the form of required action, output signal, size, shape, lifetime, mounting, pedal torque, temperature and environmental limits, etc, but did not do the detailed design.

However, Toyota sure as anything verified that the pedal DID meet the lifetime, environmental etc requirements, as well as basic functional requirements. I have specified subcontractor parts, and had to verify them. The subcontractor is 'acting as you", and one must be very sure of the QC, since basically "you" are making the parts.

goose
02-06-2010, 12:12 PM
I have the idea that maybe both sides are correct. In other words a problem created by a combination of two potential defects acting in unison. Maybe Toyota is right in that the accelerator pedals get stuck, also, maybe there is a software/eprom defect that comes apparent only when certain mechanical circumstances are met. Steve Wolzniak (spelling?) and others have noted run-away acceleration with cruise control. Would a stuck gas pedal be the catalyst of uncontrollable acceleration?

My car, which is not a Toyota, is equipped with a "speedtronic" transmission. The buttons let you shift gears like you're driving a standard (why, I don't know, it's the most useless gimmick ever) But the on board computer regulates how much I can upshift or downshift depending on speed & rpms.

Maybe the Toyota on-board computer sees WOT, and won't allow downshifting or even throwing the transmission into neutral.

It's like the Matrix, ( movie with Keanu Reeves, not a car) what's real to the on-board computer is only what's provided by the sensors.


Gary

A.K. Boomer
02-06-2010, 12:13 PM
It might be interesting to see what CTS has to say;

http://www.ctscorp.com/publications/press_releases/nr100127.htm

CTS pedals are not used in any Lexus or PRIUS models, which are also experiencing problems;

http://www.ctscorp.com/publications/press_releases/nr100203.htm

http://www.ctscorp.com/

I don't think Toyota has yet addressed the entire problem or series of problems that exist. It began with a floormat and has progressed to blaming the CTS pedal. EMI has also been mentioned in some reports. That may or may not be involved, but I think much more than a simple friction problem is involved.


By all means ALL things have to be considered and it may be a multi-compounded issue,,, But if the diagram for that pedal is real then it should never have been built... It has to go.

JCHannum
02-06-2010, 12:35 PM
I don't see a major design problem in the CTS pedal. The taper does not create a wedge effect as it is in the rotary plane. Wear could ultimately result in decreased pedal pressure, but could also create a step in the two parts that could cause the roughness described.

lakeside53
02-06-2010, 12:44 PM
How many lives have been lost due to this problem? As far as i know, the only fatalities that POSSIBLY involved this pedal assembly were from the wreck in San Diego involving the Highway Patrolman. And we still don't know the exact cause of that mishap, with an improper floormat being the most probable causal factor at this time.


No idea.. but why in the world would a software system allow incompatible operations anyhow? Brake+throttle? dumb... brake should override throttle and all this BS about shift to neutral, press brake with both feet etc etc would go away. Heck, if nothing else - if the mat was the problem, or the big mac left on the floor last week, you could still brake from full throttle.

Carld
02-06-2010, 12:57 PM
I agree, until Toyota and all the others make the brake pedal over ride the throttle no matter if the pedal sticks or the program goes crazy they are going to continue to have this problem.

I am glad our Camry is a 1998 and is cable control and my Ranger trk is cable control.

The news articles I have seen report that CTS said the pedal they make is Toyota's design and all they do is make it to the drawings as required. They say they have no input into the design at all.

Lew Hartswick
02-06-2010, 01:12 PM
What was it HAL said? something like "sorry I can not let you do that". :-)
...Lew...

Evan
02-06-2010, 01:38 PM
CTS pedals are not used in any Lexus or PRIUS models, which are also experiencing problems;


There are TWO different problems. The pedal problem does not affect LEXUS at all. That is a floormat problem. The accident with the police officer involved a floormat not even made for the vehicle.

The accelerator problem is detailed here, from Toyota:


About the Recall to Address Sticking Accelerator Pedals

On January 21, Toyota announced its intention to recall approximately 2.3 million select Toyota Division vehicles equipped with certain accelerator pedal mechanisms that may, in rare instances, mechanically stick in a partially depressed position or return slowly to the idle position. Toyota vehicles affected by the recall include:

• Certain 2009-2010 RAV4
• Certain 2009-2010 Corolla
• 2009-2010 Matrix
• 2005-2010 Avalon
• Certain 2007-2010 Camry
• Certain 2010 Highlander
• 2007-2010 Tundra
• 2008-2010 Sequoia

No Lexus Division or Scion vehicles are involved in these actions. Also not involved are Toyota Prius, Tacoma, Sienna, Venza, Solara, Yaris, 4Runner, FJ Cruiser, Land Cruiser, Highlander hybrids and certain Camry models, including Camry hybrids, all of which remain for sale.

Further, Camry, RAV4, Corolla and Highlander vehicles with Vehicle Identification Numbers (VIN) that begin with "J" are not affected by the accelerator pedal recall.

In the event that a driver experiences an accelerator pedal that sticks in a partial open throttle position or returns slowly to idle position, the vehicle can be controlled with firm and steady application of the brakes. The brakes should not be pumped repeatedly because it could deplete vacuum assist, requiring stronger brake pedal pressure. The vehicle should be driven to the nearest safe location, the engine shut off and a Toyota dealer contacted for assistance.

Separately from the recall for sticking accelerator pedals, Toyota is in the process of recalling vehicles to address rare instances in which floor mats have trapped the accelerator pedal in certain Toyota and Lexus models (announced November 25, 2009), and is already notifying customers about how it will fix this issue. In the case of vehicles covered by both recalls, it is Toyota’s intention to remedy both at the same time.

Detailed information and answers to questions about issues related to these recalls are available to customers at www.toyota.com/recall and at the Toyota Customer Experience Center at 1-800-331-4331.

J Tiers
02-06-2010, 01:43 PM
No idea.. but why in the world would a software system allow incompatible operations anyhow? Brake+throttle? dumb... brake should override throttle and all this BS about shift to neutral, press brake with both feet etc etc would go away. Heck, if nothing else - if the mat was the problem, or the big mac left on the floor last week, you could still brake from full throttle.

Absolutely.....

EVERY other quibble is just stepping around the big pile of dung in the room......

Toyota KNEW this was an issue, HAVE known it for YEARS, and have done nothing to fix it in the definite and complete way that other manufacturers have already done, which is to make the safety system over-ride the throttle. that solution is not exactly an innovation now...... it is well known

yes, if you are a LEO, and need to make 'J-turns" etc, maybe that should be removed. But for the generality of the dumb-as-a-brick driving public, there is no need for the car to perform any of those actions.

Virtually any situation in which that sort of combination might be helpful is one in which the driver has almost certainly had "prior opportunities to avoid" it, and chose not to. You cannot really make a useful vehicle which will also avoid every single danger, voluntary or accidental, at a price which makes it useful to design it.

The Denso pedal can stick also..... it just takes a different set of circumstances. Not one of you can design a pedal which *cannot* "stick"....... not you, not anyone. if it is mechanical, stuff can happen.

Evan
02-06-2010, 02:10 PM
Toyota KNEW this was an issue, HAVE known it for YEARS, and have done nothing to fix it in the definite and complete way that other manufacturers have already done, which is to make the safety system over-ride the throttle. that solution is not exactly an innovation now...... it is well known


Ford has the same problem. Why aren't they recalling everything in sight?

JCHannum
02-06-2010, 02:16 PM
There are TWO different problems. The pedal problem does not affect LEXUS at all. That is a floormat problem. The accident with the police officer involved a floormat not even made for the vehicle.

The accelerator problem is detailed here, from Toyota:

They may or may not be different problems. Toyota seems to be having problems with several of its vehicles that have the same net effect. Is the floormat the real problem or simply a convenient excuse? It sounds a little fishy to me to say the least and I don't buy it or the CTS pedal problem either.

It appears they are plugging one hole in the dike only to have another one spring up somewhere else. Blaming the driver, floormat and/or suppliers are only dodges to avoid adressing an underlying problem in the vehicle's control system that permits these side issues to manifest themselves in accidents. Other manufacturers with the same conditions present are not experiencing these same type of accidents to the degree Toyota is.

lazlo
02-06-2010, 02:27 PM
Bad news: The Prius is one of the cars with electric power steering. See:

http://www.aa1car.com/library/steering_power_electric.htm

That's not the problem -- there are plenty of modern cars with servo-driven steering. My M3 is completely fly-by-wire: steering, brakes, accelerator, active suspension and the double-clutch transmission. F1 racers have had fly-by-wire throttles and clutches since 2001, and the high-end street bikes from Yamaha and Ducati have had fly-by-wire throttles since 2006.

Like Cameron says, this sounds a lot like a software problem, that they're trying to fix with the mechanical linkage.

MrSleepy
02-06-2010, 02:46 PM
My favourite sport is F1.....
and now that Toyota have pulled out I couldn't care less if they went bust...I dont drive one...always a VW.....

That said...It does seem that these problems are widespread among the manufacturers and that Toyota are been singled out by the union of obama plc as a fall guy....

Its to Toyotas credit that they are coming clean and trying to sort these problems... I'd rather be driving a Toyota with known problems and fixes in the pipeline than a car made by the companies who know their issues...but would rather keep them secret...behind a wall of lawyers..

Rob

SpyGuy
02-06-2010, 02:57 PM
Spyguy, tell me you're not serious.
It sounds like you followed the other thread as well, so after listening to the frantic 911 call, do you honestly think the caller was thinking..."gee I'm going to sue the pants off of my brother in law if I get out out of here"? They were praying for their lives for crying out load...not tort actions!
Seems you are searching for a lot of conspiracies here, first Obama, and now the brother in law.

Go back and read the original post (http://bbs.homeshopmachinist.net/showpost.php?p=518363&postcount=24) I was replying to (and which I QUOTED in my post). Is reading comprehension a lost art?

That accident had NOTHING to do with the Highway Patrolman accident which you are referring to. In the accident I was commenting on, I doubt there was a 911 call (from Carld's story, it sounds like the accident would have occurred much too quickly for someone to say much, even if already on the phone). And the driver (and presumably the passenger) had engaged a lawyer after the fact. If not for a tort action, what do you think that lawyer is for?

Weston Bye
02-06-2010, 03:04 PM
There must be some sort of problem (probably not so serious)with the CTS pedal assembly, or we would be hearing a lot of screaming denials. Or knowing where their bread is buttered, they are taking the fall. I doubt it, the CTS-Toyota relationship is probably toast. I've seen such things from the inside.
The shim is addressing a real or suspected or potential or percieved or imagined defect. They may be trying to play CYA and fixing the problem before it becomes a problem. Whatever, Toyota seems to be playing up the shim sham, if that's what it is.

There are other problems out there, some minor, some serious. But all elevated to crisis proportion by one high profile incident.

Weston Bye
02-06-2010, 03:15 PM
..I read the other day about electric motors in the Chevy Cobalt steering system instead of hydraulics. They apparently are having problems also. Is it true that the system uses electric motors for power assist?

Den


I just heard this morning on NPR's Car Talk, Click and Clack (Experts?) that Chevrolet is using an electric motor to drive the hydraulic pump in the power steering only when called upon rather than driving the pump continuously from the fan belt. Fuel savings. I wonder if the cost of the thing will be recovered in the fuel savings it generates. Harrumph!

Anyway, the failure mode is just loss of power assist - no different than breaking a belt.

SpyGuy
02-06-2010, 03:39 PM
I just heard this morning on NPR's Car Talk, Click and Clack (Experts?) that Chevrolet is using an electric motor to drive the hydraulic pump in the power steering only when called upon rather than driving the pump continuously from the fan belt. Fuel savings. I wonder if the cost of the thing will be recovered in the fuel savings it generates. Harrumph!

Anyway, the faulure mode is just loss of power assist - no different than breaking a belt.

Seems an electro-magnetic clutch (as used on automobile AC compressors) would be a less expensive solution (and weigh less). The only advantages I see to using an electric motor are:

1. The hydraulic pump can be moved out of the plane of the belt driven accessories. In fact, it wouldn't even need to be in the engine compartment.

2. The speed of the pump can be varied by computer control for various power assist conditions.

Willy
02-06-2010, 04:15 PM
*****************

Evan
02-06-2010, 04:21 PM
They may or may not be different problems. Toyota seems to be having problems with several of its vehicles that have the same net effect. Is the floormat the real problem or simply a convenient excuse? It sounds a little fishy to me to say the least and I don't buy it or the CTS pedal problem either.



On what do you base your opinion? The ECU has been investigated multiple times by the NHTSA and they have cleared it every time. They refuse to investigate it again as a waste of time and money. Every car maker has complaints of unintended acceleration. The average American driver hasn't a clue what makes a car run or what to do in an emergency.

From Consumer Reports:



Representative Toyota owner comments pulled from the NHTSA database:

“While entering an on-ramp the [2008 Tacoma] truck accelerated on its own, going out of control crashing sideways into a guard rail…”

Sure thing. I bet his insurance company doesn't believe it.

“My 2008 Prius accelerated almost out of control. I was merging onto an expressway when the accelerator seemed to have a life of its own and took off at an incredibly high rate of speed…”

A Prius? Incredible rate of speed? Make me laugh.

“I felt the vehicle [2008 Lexus ES 350] increasing in speed to about 90 mph, without depressing the accelerator. I had been on cruise control at about 73 mph… [A] passenger screamed at me to slow down. I was unable to do so, even after stepping forcefully on the brakes.”

Sounds like a cruise control issue. Perhaps set to "Accelerate"? Also, the car WILL SLOW DOWN if you step on the brakes.



http://blogs.consumerreports.org/cars/2009/12/sudden-unintended-acceleration-sua-analysis-2008-toyota-lexus-ford-gm.html

saltmine
02-06-2010, 04:48 PM
In regard to GM power steering.... The Chevy Cobalt uses an electric motor steering boost assembly between the steering column and the steering rack.It's basically a planetary geared motor which responds to steering inputs much like conventional hydraulic power steering. There have been some minor glitches found in the sensors but no real failures or dangerous problems.
The HHR also uses a similar steering assist. The heavier GM cars use conventional power steering with the exception of the Hybrids which have electrically powered pumps which run on demand only.
Many of he hybrids on the road today use electrically powered steering in one form or another. The electric power steering can fail, but the system reverts to manual steering should it ever fail. So, you can still control the car.

When I worked in Fleet, we had several incidents where cars would "run away" with ucontrolled accelleration. Mostly Ford products, the failure turned out to be faulty cruise control switches and at times the "cruise disengage" switch on the brake master cylinder. Yes, the same switch that has been recalled for starting numerous fires.
It was found that the cruise control switch would short out and command the control to accelerate the car. As long as the switch was shorted, the car would continue to accelerate, until one depressed the brake. Which would shut down the entire cruise control.

It's very possible that this is happening in the Toyotas in question....but who am I to tell, I'm just an old retired guy.

JCHannum
02-06-2010, 05:20 PM
On what do you base your opinion? The ECU has been investigated multiple times by the NHTSA and they have cleared it every time. They refuse to investigate it again as a waste of time and money. Every car maker has complaints of unintended acceleration. The average American driver hasn't a clue what makes a car run or what to do in an emergency.

From Consumer Reports:



http://blogs.consumerreports.org/cars/2009/12/sudden-unintended-acceleration-sua-analysis-2008-toyota-lexus-ford-gm.html

My opinion is stated in the second paragraph of my post. I make no mention of the ECU, only that there appears to be a problem with their control systems.

Your own link to the Consumer Reports verifies that there is a highly disproportionate number of complaints regarding problems with Toyota, 41% compared to the next highest, Ford with 28%. When compared to the manufacturer's market share the figures are much worse.

Evan
02-06-2010, 06:17 PM
When compared to the manufacturer's market share the figures are much worse.

No they aren't. That is compared to market share. Ford also has a disproportionate share of complaints.


I make no mention of the ECU, only that there appears to be a problem with their control systems.


The ECU IS the control system. The throttle position sensor connects directly to the ECU which then regulates the engine output based on the throttle pedal position.

sbmathias
02-06-2010, 07:16 PM
Which do you mean?
You state brakes in first post, but show accelerator pedal in second post.
Advise please...
Tom
My bad. I'm talking only about the accelerator pedal fix for now. Looks like this whole topic gets people excited about the whole fiasco.
Some here have proposed that the interlocking wedgie things are for pedal "feel". That may be, but it seems like there should be a much easier way to accomplish that than this convoluted design. I've made many mechanisms with plenty of inherent friction!

Evan
02-06-2010, 08:19 PM
It is for pedal feel. Try to imagine a pedal that was mounted via a ball bearing and a light spring. No chance of sticking from the mount but nearly impossible to drive smoothly. There would be no feedback to your foot and no support for your foot when trying to hold it at a steady position.

It isn't easy to replicate the mechanical feel of a linkage or sheathed cable by using some simple friction mechanism. It must have some stick/slip but that stiction must never be stronger than the return spring, obviously.

JCHannum
02-06-2010, 09:36 PM
No they aren't. That is compared to market share. Ford also has a disproportionate share of complaints.



The ECU IS the control system. The throttle position sensor connects directly to the ECU which then regulates the engine output based on the throttle pedal position.

It is not market share. The 41% figure is the percentage of complaints registered for Toyota vehicles versus other manufacturers. Toyota's average market share was 16%. GM's figures were 5% of the complaints while they had 23% of market share, which is the best record of the lot compared relative to market share. The figures are from the 2007-2008 model year. I suggest you reread the report for clarification if you do not understand it.

The vehicle's control system is the entire system, brakes, steering, etc. as well as the connecting cabling, sensors, speed indicators and anything else related. It is not necessarily limited to the ECU, but encompasses all facets of what is needed to control the vehicle. It might not be in the ECU itself, but a transient or something external that creates the problem.

Weston Bye
02-06-2010, 09:42 PM
All of what Evan said. Moreover, it must perform reliably and consistently over a wide range of temperature (-40°C to 85°C for passenger compartment applications) and humidity, as well as tolerate various mixtures of dust and salt fog. Product validation tests require cycle testing, (hunderds of thousands to millions) EMC and ESD testing for electronic devices, and so on. Even with all this, stuff happens.

Weston Bye
02-06-2010, 09:56 PM
The vehicle's control system is the entire system, brakes, steering, etc. as well as the connecting cabling, sensors, speed indicators and anything else related. It is not necessarily limited to the ECU, but encompasses all facets of what is needed to control the vehicle. It might not be in the ECU itself, but a transient or something external that creates the problem.

Yep, all true, but such transients, or any other unintended operation, must be accounted for - a Hurculean task, but necessary.

I can relate that there is a different mindset required when dealing as a supplier to Japanese automakers - they generally make good products, but getting to a good design is, well, difficult.

Black_Moons
02-06-2010, 10:11 PM
OK i have an amazing idea for the friction device to simulate a control cable

What you do, is take apart an existing old car, since they are obsolete and you can't even get parts for, yadayadarantrant, steal the throttle cable and spring, connect that to the pedal with the spring at the end of the throttle cable... And.. Done.

Just a thought. :P

Toolguy
02-06-2010, 10:16 PM
All they need is a heavier spring on the pedal with no friction device.

lakeside53
02-06-2010, 10:20 PM
OK i have an amazing idea for the friction device to simulate a control cable

What you do, is take apart an existing old car, since they are obsolete and you can't even get parts for, yadayadarantrant, steal the throttle cable and spring, connect that to the pedal with the spring at the end of the throttle cable... And.. Done.

Just a thought. :P


LOL... I was going to suggest a similar thing, but just use the Chinese aftermarket cable/spring for my 1990 Mazda truck, or whatever.

Gheeze... how hard is this all really...:confused:

SpyGuy
02-06-2010, 10:20 PM
All they need is a heavier spring on the pedal with no friction device.

Nope. Try it.

Imagine a car's supension with only springs but no friction dampers ("shock absorbers").

Toolguy
02-06-2010, 10:23 PM
This is a totally different function than suspension.

Evan
02-06-2010, 10:43 PM
It is not market share. The 41% figure is the percentage of complaints registered for Toyota vehicles versus other manufacturers. Toyota's average market share was 16%. GM's figures were 5% of the complaints while they had 23% of market share, which is the best record of the lot compared relative to market share. The figures are from the 2007-2008 model year. I suggest you reread the report for clarification if you do not understand it.


I suggest you need remedial classes in reading comprehension. From the report:



As major automakers, Toyota Motor Corporation and Ford Motor Company sell more vehicles than most competitors. To put the figures into proper perspective, we compared the number of complaints against overall market share.

SpyGuy
02-06-2010, 10:50 PM
This is a totally different function than suspension.

The function may be different, the physics are the same. I take it you're not an engineer, right?

Ok, to put this in a simpler way to understand, have you ever tried driving the bumper cars at an amusement park or fair? Those cars have a simple spring-loaded accelerator linked to a rheostat. No feedback friction or "feel" in the pedal. Not a big problem since (1), most people drive bumper cars with the pedal on the floor; (2) the driving surface is flat, level, and smooth; (3) they are low-energy vehicles; (4) they are confined to a closed course. But try to imagine an accelerator like that on your open highway car.

steve45
02-06-2010, 10:50 PM
When I worked in Fleet, we had several incidents where cars would "run away" with ucontrolled accelleration. Mostly Ford products, the failure turned out to be faulty cruise control switches and at times the "cruise disengage" switch on the brake master cylinder. Yes, the same switch that has been recalled for starting numerous fires.

It was found that the cruise control switch would short out and command the control to accelerate the car. As long as the switch was shorted, the car would continue to accelerate, until one depressed the brake. Which would shut down the entire cruise control.

It's very possible that this is happening in the Toyotas in question....but who am I to tell, I'm just an old retired guy.
This is exactly what I've been thinking. Drive-by-wire or not, if it has cruise control, it has an electrically actuated servo and related electronics that can be affected by EMF, moisture, corrosion, etc.

My fear is that this will get the same BS treatment as the bogus TWA Flight 800 crash investigation got. Oh, yea, they said that wiring in the fuel tank caused it to blow up, but why didn't they ever ground the airplanes? How does a fuel tank explode if it doesn't have air in it??? How could so many people on the ground, including a certified expert engineering witness, a certified NOAA weather observer, 2 National Guard pilots, etc. see an object rise from the surface and strike the airplane, yet the NTSB ignored them??????

I don't know if we'll ever get the truth about the accelerator problem...

JCHannum
02-06-2010, 11:06 PM
I suggest you need remedial classes in reading comprehension. From the report:

Yes, they did compare the complaints against market share. Close examination of the chart header reveals individual columns for each category;

Manufacturer

2008 Model Year Complaints

Share of Complaints

Market Share

The chart shows that while Toyota had 16% of market share, they had 41% of the complaints. That is a comparison of complaint percentage vs percentage of market share. It is really pretty straightforward.

lazlo
02-06-2010, 11:06 PM
My fear is that this will get the same BS treatment as the bogus TWA Flight 800 crash investigation got. Oh, yea, they said that wiring in the fuel tank caused it to blow up, but why didn't they ever ground the airplanes? How does a fuel tank explode if it doesn't have air in it??? How could so many people on the ground, including a certified expert engineering witness, a certified NOAA weather observer, 2 National Guard pilots, etc. see an object rise from the surface and strike the airplane, yet the NTSB ignored them??????

That's a different story though -- a lot of folks, including the FBI, were convinced TWA 800 was shot down by a shoulder-launched missile. It took the NTSB four years to come up with a completely implausible explanation, but I think that was the government's way of shielding us from the first terrorist attack, in 1996.

We gave the Mujahideen 5,000 Stingers during the Russian invasion of Afghanistan, which ended in 1989, so it's very possible that many were still operational 7 years later.

Arcane
02-06-2010, 11:11 PM
Even when there are eye witnesses and pictures to back them up, government officials will still deny, deny, deny there ever was such an event as evidenced by the latest occurrence in Newfoundland. http://www.thestar.com/news/canada/article/757495--french-missiles-or-just-toy-rockets-mystery-deepens-in-newfoundland

J Tiers
02-06-2010, 11:16 PM
Ford has the same problem. Why aren't they recalling everything in sight?

Perhaps because the problems have not killed enough people to get the NHTSA excited......

or perhaps because the problems are not as prevalent nor as identifiable with a specific part as the Toyota ones..................

In order to do a recall, you must have some sort of 'fix", and you must have a recognizable 'target" of the fix....... unless you propose to simply buy back all the cars and scrap them.

Carld
02-07-2010, 12:08 AM
I don't buy that crap about a friction free throttle being hard to control. If you are trying to control the throttle with your foot hanging in the air or just your heel on the floor then you deserve sore tired muscles. All the cars and trucks I had in the past with direct lever and rod linkage were mostly friction free and I always kept them lubed to be that way. I wanted instant response and a direct feel of the throttle. If it had any friction to delay closing the throttle I fixed it. If your a wuss then don't drive a real car.

A hard spring on the throttle is much easier to control than a soft spring and if you don't position your foot to use the throttle with the least effort and best control then quit driving.

From reading the article that Evan posted I can see now how the shim works but I am not convinced that is the problem. That does not explain the sudden WOT while at a stop or when just riding along the streets or highway.

I don't think they really know what the problem is and are just shooting in the dark hoping they hit the target.

From what I have read this has been going on since before 2005. Just when did they start using throttle by wire?

lazlo
02-07-2010, 12:12 AM
Even when there are eye witnesses and pictures to back them up, government officials will still deny, deny, deny there ever was such an event as evidenced by the latest occurrence in Newfoundland. http://www.thestar.com/news/canada/article/757495--french-missiles-or-just-toy-rockets-mystery-deepens-in-newfoundland

Wow, I didn't know there was French territory next to Newfoundland.

Canada is, of course, part of the "5 Eyes" -- the tight intelligence community of Canada, US, UK, Australia, and NZ. If the French really launched a missile over Newfoundland, the Canadian government would have been notified within minutes. Now whether they would tell their citizens about it...

danlb
02-07-2010, 01:35 AM
I see so many people expecting perfection, when they are perfectly satisfied with an older design that is full of parts designed to last only as long as necessary.

If we are going to call for a recall of every car that can fail, we should recall every model that doesn't have safety interlocks on the steering, brakes, transmissions, etc. If we want to get really safe, if should refuse to start if ANY safety component fails. That would, of course, include turn signals, horn and tail lights.

But even if we don''t go that far, It would be nice if they would at least use positive return cables and maybe an 'emergency stop' switch like we expect to find on our shop machines.

Dan

Evan
02-07-2010, 02:45 AM
I think an "e-stop" is a much better idea than mixing the brake and accelerator functions together. The heart of these problems is in most cases driver incompetence in some way but the solution is easy. For vehicles with no key and even ones that have a key the "stop engine" function should be a separate button set below the surface of the dash with a clearly visible label that reads "STOP ENGINE". It should act immediately and should not reset the start function until the vehicle comes to a complete halt.

SpyGuy
02-07-2010, 04:19 AM
For vehicles with no key and even ones that have a key the "stop engine" function should be a separate button set below the surface of the dash with a clearly visible label that reads "STOP ENGINE". It should act immediately and should not reset the start function until the vehicle comes to a complete halt.
I'm sure your e-stop button would cause FAR MORE accidents and problems than the statistically insignificant number of "unintended acceleration" situations that the button is supposed to prevent. Especially when you realize that most unintended acceleration mishaps occur not on the open highway, but rather while stopped or maneuvering in or out of parking, and that the event ends in mere fractions of a second when the vehicle impacts the stationary object just in front or behind the vehicle when the driver accidentally hit the gas... errr... experienced the unintended acceleration.

philbur
02-07-2010, 06:15 AM
Even concert violinists occasionally play a wrong note.

Phil:)



it is like playing a violin.... where there are no frets, fingers go "where the note is" automatically.

Carld
02-07-2010, 09:23 AM
Got to thinking last night after shutting the 'puter off, I'm a wuss about a soft throttle spring or to much friction so what the heck difference is there. Oh well.:o

lazlo
02-07-2010, 10:28 AM
I see so many people expecting perfection, when they are perfectly satisfied with an older design that is full of parts designed to last only as long as necessary.

I think it's a bigger issue is that, as fly-by-wire cars become more prevalent, there needs to be exhaustive hardware/software/system testing.

The commercial airliners went through a painful learning process when they started dabbling in fly-by-wire aircraft with the Airbus 320.

Evan
02-07-2010, 10:34 AM
I checked out our new Jeep Patriot yesterday. It does not have a brake override system, which is fine with me. Also, the 4 wheel discs easily bring it to a halt against the engine but it is only 150hp.

That brings up another point. Driving a 2wd vehicle in poor traction conditions would really suck with a brake override. A standard trick for vehicles without traction control is to lightly apply the brakes with the throttle to stop a wheel that is spinning and transfer power to the other wheel.

A.K. Boomer
02-07-2010, 11:55 AM
I don't see a major design problem in the CTS pedal. The taper does not create a wedge effect as it is in the rotary plane. Wear could ultimately result in decreased pedal pressure, but could also create a step in the two parts that could cause the roughness described.

If the taper does not create a "wedge effect" then whats causing the friction?:rolleyes:
You have things exactly the opposite ---
One needs to especially pay attention to tapers when in the "rotary plane" as you describe (be it band or drum) --- all this means is that they have even more potential to become "self energizing" with the tapers engagement upon each other.

The problem with systems like these is the modulation can be very inconsistent,
These type of frictional devises should NEVER be used for throttle control PERIOD.

If they didnt have the room right at the pedal to build a nice little multi-disc precision unit then they should use a typical cable actuated one and mount it in an accessible area under the dash somewhere or under the hood -- throw in a few 45 degree bends and the cable running through the teflon sheathing will already have most of the resistance that you already need anyways and in fact if its long enough and you work it against the correct spring and pivot you wont need anything else.

You want to learn the effects of what frictional tapers can do in a rotary plane build a brake system with drum brakes and cut serpentine groves into the shoe's, now cut mating groves into the drums ---------- At 45 degree's its a fraction of the taper effect as shown in the throttle diagram, Now - disconnect your power brake unit because you wont need it anymore, and good luck not flat spotting your tires because even with the slightest pedal pressure your screwed ------- you have zero ability to modulate, the brakes go instant gridlock as they are designed to be self energizing in the first place...

Just because the throttle control piece is a single frictional unit off to one side does not mean it cannot self energize - The very nature of a taper under load and being rotated into another taper is "self energizing", but unlike a flat disc surface pressed up against another flat surface area its modulation energies have much more of a "mind of their own" and are more prone to erratic behavior -------- This isn't some kind of a "guess" of mine,
its a law of physics engineering fact, Temperature, humidity, age of plastic and lube, and on and on...

A precision disc that's loaded on both sides by the same diameter friction material is immune to the extreme modulation flaws and if the materials are selected properly can never self energize as its load ratio's not only remain a constant - its engagement vector is 90 degree's and therefore cannot be manipulated by either direction of rotation or pivoting looseness, ( torsional free play will indeed result in pedal looseness but will not change the load vectors)
Also the surface area is one and the same everywhere as the friction material is also a disc of the same diameter -- so there is never a chance of building up wear patterns that can cause future gridlocks as everything remains a constant... (Talking a unit built for slight resistance like throttle control -- please spare me examples of overheated automobile clutch packs:rolleyes: )
My toyota is 18 years old - wonder what these throttle "wedgie" devises will be doing in 15 years...

Fact;
There's allot of people in the world today who have these things called "degree's" that don't know their ass from their elbows...

J Tiers
02-07-2010, 12:37 PM
I think an "e-stop" is a much better idea than mixing the brake and accelerator functions together. The heart of these problems is in most cases driver incompetence in some way but the solution is easy. For vehicles with no key and even ones that have a key the "stop engine" function should be a separate button set below the surface of the dash with a clearly visible label that reads "STOP ENGINE". It should act immediately and should not reset the start function until the vehicle comes to a complete halt.

An easily accessible "cut the wheels off the car" button I suspect would be a very dangerous item to have.

If pushed accidentally in highway traffic, it leads to the immediate 30 car pileup scenario.....

And, NO it is NOT "like turning off the key" as will no doubt be suggested, because it IS "easily accessible". if it were not easily accessible, it would be useless.







That brings up another point. Driving a 2wd vehicle in poor traction conditions would really suck with a brake override. A standard trick for vehicles without traction control is to lightly apply the brakes with the throttle to stop a wheel that is spinning and transfer power to the other wheel.

Nonsense.

Am I to assume that in that condition you lock the wheels with the brakes? By a full-on brake application with max pressure?

I don't think so.

You assume that ANY slight application of the brakes should bring the engine to a shuddering halt........ NOT SO, of course. Brakes have settings other than "locked" and "not applied", and brake override obviously should be limited to harder braking, so the argument is without significant merit.

The pressure to use is easily obtained by testing a sampling of people.
.
.
The huge merit of the brake over-ride is that it USES THE NATURAL ACTION OF THE DRIVER. Most other solutions require that the driver "reason out a series of actions" while in an emergency situation.

It has already been proven that even people who, due to their background should be competent in emergency situations, will in fact fail to take reasonable actions. If a highway patrolman, who almost certainly HAS taken advanced driving lessons, and should be used to emergencies, fails to do the right thing, then there is absolutely no way you have any right to expect "Mrs Annie Jones" who has a car full of screaming kids to do better.
.
.
.
AKBOOMER:

So you think your friction device cannot lock or hang up? Good luck..... but don't bet your house on it

EVERY mechanical device can fail in various ways, AND YOU ARE ATTACKING THE WRONG POINT IN THE SYSTEM ANYWAY.

IT HAS NOTHING TO DO WITH THE PEDAL. the pedal is a means, the ACTION is advancing the throttle.

So the point of the matter is not the pedal, but rather a condition wher the control system is faced with a full throttle condition, and another input which is requesting full stopping power. In such a situation, the control system MUST assume that the safety system is to be believed, and reduce the engine rpm / power output. otherwise the same exact scenario can happen again and again, with different causes each time.

You are merely trying to plug one hole in the dike, stepping around the real problem.

A.K. Boomer
02-07-2010, 01:17 PM
.
.
AKBOOMER:

So you think your friction device cannot lock or hang up? Good luck..... but don't bet your house on it

EVERY mechanical device can fail in various ways, AND YOU ARE ATTACKING THE WRONG POINT IN THE SYSTEM ANYWAY.

IT HAS NOTHING TO DO WITH THE PEDAL. the pedal is a means, the ACTION is advancing the throttle.

So the point of the matter is not the pedal, but rather a condition wher the control system is faced with a full throttle condition, and another input which is requesting full stopping power. In such a situation, the control system MUST assume that the safety system is to be believed, and reduce the engine rpm / power output. otherwise the same exact scenario can happen again and again, with different causes each time.

You are merely trying to plug one hole in the dike, stepping around the real problem.


JT, every action has a reaction - Your right there is no way to implement a 100% failsafe and never will be, but you can minimize risk in the first place ------ I don't give a rats ass if they find out its the cars computer or what -- that pedal system is an engineering NO-NO
As far as what to do after the fact of when the pedal sticks Goodie for you if you can prove a foolproof system - but you can't, again EVERY ACTION HAS A REACTION

Me and you been down this road before, Do you have any idea the chaos you will create with the millions of vehicles on the road if you use the vehicles brake pedal to cancel out the throttle at all times?

Like I stated earlier all guys who have a size 13 shoe will be dead within the week along with anybody wearing work boots also,
Your solution is to heap control on top of control, WRONG ANSWER!
Lets not panic and because the cast iron skillet is getting a little warm take a direct leap head first into the fire.
Lets just do what the other people are doing and create a properly engineered throttle control, ECU, floor mat whatever...
Keep it simple _ _ _ _ _ _!

What happens when you create a constant link between the brake canceling out the throttle at all times?
Youv just thrown in a handful of other components that have to work FLAWLESSLY (brake sensor, ecu connections and circuity) AT ALL TIMES or someone might lose acceleration at a critical moment WRONG ANSWER !

You think we got problems now?

Evan
02-07-2010, 02:37 PM
Am I to assume that in that condition you lock the wheels with the brakes? By a full-on brake application with max pressure?


Reading comprehension Jerry, practise it.

I wrote and you quoted: "A standard trick for vehicles without traction control is to lightly apply the brakes with the throttle to stop a wheel that is spinning and transfer power to the other wheel."


You assume that ANY slight application of the brakes should bring the engine to a shuddering halt........ NOT SO, of course. Brakes have settings other than "locked" and "not applied", and brake override obviously should be limited to harder braking, so the argument is without significant merit.


I haven't the slightest idea what you are now talking about. Certainly it isn't related to anything I posted.

As for brake override I expect it is part of the brake light circuit. It would have to be for safety reasons.

Carld
02-07-2010, 03:23 PM
Any throttle by wire system will always be subject to failure until it has a brake pedal interlock to disable the engine no matter what happens.

The program should be set so that anytime your foot hits the brake enough to trip the brake light switch the throttle is disabled PERIOD. The average driver needs that safety over ride while an experienced race driver may not.

The drivers that use both feet to drive will just have to learn not to ride the brake. My neighbor is a retired NASCAR driver and uses both feet but he DON'T ride the brake. He said the drivers quickly learn if they ride the brake they soon don't have any brakes and at 150 to 200 mph entering a turn they hit the wall. It's a learning curve they don't forget.

J Tiers
02-07-2010, 03:58 PM
Reading comprehension Jerry, practise it.

I wrote and you quoted: "A standard trick for vehicles without traction control is to lightly apply the brakes with the throttle to stop a wheel that is spinning and transfer power to the other wheel."



I haven't the slightest idea what you are now talking about. Certainly it isn't related to anything I posted.

As for brake override I expect it is part of the brake light circuit. It would have to be for safety reasons.

What I wrote is because your statements made negative sense. They could only be answered with equal nonsense, assuming you are referring to brake over-ride.....

No. I do NOT suppose that the slightest tap on the brake should shut down the motor.... Nor would the brake light circuit be appropriate...... other than for exiting normal use of the cruise control....

A city car is unlikely to need the "mud-hole technique", nor is the driver likely to know how to do that. But let that ride. In any case, it is quite easy to distinguish "normal abnormal" braking of the type you suggest from emergency response.

If you suppose that a driver faced with sudden acceleration out of control will respond with tentative light taps on the brake, I suggest you are living in cloud-cookoo land...... Such a driver is going to stand on the brakes as hard as possible.

Unless I misread what you wrote, that is NOT what you suggested, so I fail to see how your entire comment is relevant to a hard braking emergency situation.

hard braking is one of two cases, either of which is a reasonable cause for reducing engine power output....

1) "high" pressure in at least one of the two brake line systems (to be determined by survey) plus advanced throttle

2) brake pedal at maximum travel (indicating brake application but brake failure), plus advanced throttle

The combination of hard braking and open throttle is the tip-off, and only in the most remote instance is it reasonably seen to be the ONLY way out of the situation. Nor are very many of such situations equal in hazard to a runaway throttle, which we KNOW is possible, since it seems to happen with sufficient probability to induce the recall of and corrections to millions of cars from the one most affected manufacturer..

You will note that in the cases of genuine throttle "lock", from whatever cause, be it floormats, cables, pedal sticking, EMI to the TPS, broken wires, etc, an interlock prevents a runaway BY USING THE DRIVER'S NATURAL REACTIONS.

And of course it in NO WAY prevents a driver from using another method, like the ignition key, "start/stop" button, etc.

Just HOW HARD is it to comprehend and accept that?

A.K. Boomer
02-07-2010, 04:57 PM
The program should be set so that anytime your foot hits the brake enough to trip the brake light switch the throttle is disabled PERIOD.



I believe this to be very dangerous thinking, In many cases I rely on my throttle working just as much as my brakes (intersections - passing - merging)

Cars are not a stop only concern --- we "shuffle" along -- we need to do so to exist out there.
Only in a cruise control application should this be applied.

How would you like your brake to be canceled at any given moment?


How long are you going to disable the throttle before someone can get back to business and get the hell out of someone's way?

Then what? after everybody starts dying in side collisions we make side airbags and steel guard rails inside the doors mandatory, Ooops -now cars weigh more and when their the ones hitting the others in the side they will kill more often, Fix the problem - don't create bigger ones.

Credits to JT for coming up with a more refined version but points taken away at the same time for adding tons of complexity.... ( = things that can and will go wrong )

MrSleepy
02-07-2010, 05:10 PM
The program should be set so that anytime your foot hits the brake enough to trip the brake light switch the throttle is disabled PERIOD. .

So when your 3/4 down the last bottle of vodka....rushing to the offie before it shuts in 10mins...the fasted way to get there is to "heel n toe" the brake and throttle to avoid turbo lag when cornering past the school :p ...

The Fins,Swedes, and Icelanders will be well fragged off if you disable heel n toe driving...It could wipe out the chance of being world rally champions...:).

Rob

Carld
02-07-2010, 05:49 PM
AK, it's easy, hit the brake and the engine goes to idle, release the throttle and push the throttle and your going again.

However, I do like JT's idea of hard brakes with WOT either from the pedal or the computer to shut the engine either down or to idle, I would prefer idle so it still gives steering and brake control.

A.K. Boomer
02-07-2010, 06:54 PM
Not that easy, first rule of thumb for somebody who's experiencing something of this nature is to tromp down on the throttle even more, remember -- were dealing with the general public here, if they can't figure out that they can drain a power brake unit by applying the brake pedal a few times what makes you think there going to put together that the problem is a throttle override system and have the ability to "re-set" it in a split second,

So the situation goes something like this,,, pulling out left turn from stop with semi truck coming from left at safe distance upon current car acceleration rate BUT throttle stops working - subject presses down harder on accelerator, nothing happens, Semi-truck connects with drivers side door at 60 mph, everybody dies except the semi driver (who later takes his own life when he finds out the guy driving the car was just out to pick his 400 lb wife up some Hog-n-daus):(

Every situation has its repercussions...

Second thought Carld, How are you going to re-set the throttle when the throttle itself is jammed?
and If its an electrical failure how are you going to rely on it when it just let you down?

This aught ta be good.....

lazlo
02-07-2010, 07:54 PM
Any throttle by wire system will always be subject to failure until it has a brake pedal interlock to disable the engine no matter what happens.

And what about the brake by wire system? What about the steering by wire system?

There are many fly-by-wire systems that we rely on for human safety every day -- elevators, commercial airliners, traffic lights, ...

If it's a software issue, the control system should be written so that it's impossible for the throttle to run out of control. It's just as critical that they don't botch the software handling of any of the fly-by-wire signals, including the brake, or the steering control.

On my car, the steering control is software configurable by the driver from plush to razor-sharp (for track racing). What do you think would happen if that software ran off in the weeds?

Carld
02-07-2010, 08:39 PM
I told my solution long ago. I don't like any of the by wire systems and I don't own one and won't own one. I don't even like the idea that the computer controls the things it does on our vehicles.

The thing is you can insert all kinds of what if's and it is never ending. I was under the impression we were talking about the throttle by wire and I didn't know Toyota uses a brake by wire. I don't know of any car maker that uses brakes by wire. Is there one or are you all just conjuring up all these ideas with your tongue in your cheek?

I think it would be rather foolish to use brakes by wire but there are a lot of engineers out there that would try it.

aboard_epsilon
02-07-2010, 08:55 PM
So when your 3/4 down the last bottle of vodka....rushing to the offie before it shuts in 10mins...the fasted way to get there is to "heel n toe" the brake and throttle to avoid turbo lag when cornering past the school :p ...

The Fins,Swedes, and Icelanders will be well fragged off if you disable heel n toe driving...It could wipe out the chance of being world rally champions...:).

Rob

a heal and toe fly by wire throttle ..on a rocker like a see-saw ..thats the solution ..toe to accelerate ..heel to decelerate ..simples

Carld
02-07-2010, 09:00 PM
This whole thread is a maze of conjuring by everyone since we don't have knowledge of Toyota's system. We are all surmising how we think it should be or how we would do it.

Boomer said, "Second thought Carld, How are you going to re-set the throttle when the throttle itself is jammed?
and If its an electrical failure how are you going to rely on it when it just let you down?

This aught ta be good....."

I think that has been answered by everyone here with their opinions and I said something about a jammed throttle and/or computer in a past post so I'll let you look it up.

"This aught ta be good.....", ya think so, well thanks for the compliment. I didn't get the impression you cared about what I think and your opinion was the best.

In the end it don't really matter what we think or propose it's Toyota's decision and they aren't going to take our advise or even ask for it.

With that thought in mind why would anyone make light of anyone else's idea since it's just an idea and none of the ideas may even work if they were to even be considered.

Everything in this thread is for fun and conversation and if your taking anything we say here as gospel or usable your fooling yourself and being delusional.

EDIT: quit taking your selves so seriously and have fun with this thread.

lazlo
02-07-2010, 09:01 PM
I think it would be rather foolish to use brakes by wire but there are a lot of engineers out there that would try it.

There are a lot of modern cars that have brake by wire. And if you're flown on an Airbus, or a Boeing 777, those are entirely fly-by-wire.

Carld
02-07-2010, 09:05 PM
I know there are aircraft with fly by wire and they have several backup systems from what I have read.

Which vehicles on the road that are standard production vehicles that have brakes with no direct link to the master cylinder?

I don't fly commercial but I would fly charter if needed. I don't trust the commercial airlines but that is fodder for another thread not here.

lazlo
02-07-2010, 09:09 PM
Which vehicles on the road that are standard production vehicles that have brakes with no direct link to the master cylinder?

Many (all?) of the Mercedes and BMW's have had brake-by-wire since 2002. The ECU is made by Bosch:

http://www.designnews.com/article/13474-Brake_by_wire_hits_the_road.php

Carld
02-07-2010, 09:20 PM
So what your saying is the brake pedal has NO mechanical connection to the master cylinder and the master cylinder is operated by a servo of some type.

J Tiers
02-07-2010, 09:31 PM
Credits to JT for coming up with a more refined version but points taken away at the same time for adding tons of complexity.... ( = things that can and will go wrong )


No... actually, the complexity was already there, this only adds some to counteract the prior complexity that is postulated (and shown) to fail.............

Back in the old days, you COULD turn off the engine, with no nonsense about steering locks, etc.

lazlo
02-07-2010, 09:32 PM
So what your saying is the brake pedal has NO mechanical connection to the master cylinder and the master cylinder is operated by a servo of some type.

Exactly. Same thing on the steering :) My point is that consumer fly-by-wire vehicles can be done safely, and have been on the road for almost 10 years.


"The pedal feels no different than with hydraulically controlled brakes. But between the driver and the wheels, the Bosch electronics are more than just a straight, lighter-weight replacement of a hydraulically controlled and powered system. Based on driver input (such as steering angle), the motion of the car (wheel speeds, yaw), the G forces acting on it, engine speed, and transmission gear selected, the controller drives modulator valves to produce the optimum brake pressure at each individual wheel. For example, if a driver enters a turn too fast and brakes, the electronics will apply most of the brake force to the two wheels on the outside of the turn to reduce the chance of skidding. The result is effectively a four-way split in braking functions as opposed to the twin, diagonally split systems, used on conventional cars with completely hydraulic brakes (see figure).

With no hydraulics to feed pressure back into the brake pedal, when the ABS function kicks in during a panic stop the pedal remains vibration free. And how's this for electronic legerdemain: In such an emergency stop, sensors detect the quick removal of the driver's foot from the gas pedal and signal the controller to prime the system with higher pressure and move the pads lightly against the disks (this is imperceptible to the driver). As soon as the foot presses the pedal, full brake force is applied using the high-pressure hydraulic accumulator. According to Mercedes Product Specialist Dave Larsen, this results in a roughly 3% reduction in stopping distance from highway speeds. At 40 mph, the reduction is about 6.5 ft.

An electric pump pressurizes the system and an accumulator. This arrangement can deliver full braking pressure even with the engine off. And a "dry braking function" presses the pads lightly against the disks every 10-15 sec to keep them dry and ready for use when the windshield wipers are running.


The redundancy and failover mechanisms that Bosch built into the system are impressive:



If the controller fails or malfunctions, block values automatically slide open to connect the front brake disks to the brake pedal's hydraulic cylinder that now will act as a conventional master cylinder producing 80% of front braking power. Dividing pistons (check valves) in the front brake hydraulic circuits also isolate the backup system pressure from the rest of the circuit."

Evan
02-07-2010, 09:33 PM
This whole thread is a maze of conjuring by everyone since we don't have knowledge of Toyota's system. We are all surmising how we think it should be or how we would do it.


Why is it I seem to be the only person interested in finding out those answers? I found some references to the new Toyota system and it will not be a throttle cutoff. It will manage engine power according to speed, engine rpm, brake application effort and the gear the transmission is in. It will allow for braking to a stop but it will not kill the engine. It won't do much at all unless the speed in building quickly and the brake is pressed at the same time as the accelerator and the engine output is high enough to be concerned about. The only time the ECU will actually take the engine back to idle is if it has lost control of it. If that doesn't work then it will kill the fuel and ignition.

J Tiers
02-07-2010, 10:02 PM
Why is it I seem to be the only person interested in finding out those answers? I found some references to the new Toyota system and it will not be a throttle cutoff. It will manage engine power according to speed, engine rpm, brake application effort and the gear the transmission is in. It will allow for braking to a stop but it will not kill the engine. It won't do much at all unless the speed in building quickly and the brake is pressed at the same time as the accelerator and the engine output is high enough to be concerned about. The only time the ECU will actually take the engine back to idle is if it has lost control of it. If that doesn't work then it will kill the fuel and ignition.

That makes perfect sense, why did they not do this years ago?

It DOES fail AK's "simplicity test", I assume.

lakeside53
02-07-2010, 10:16 PM
Probably because their lawyers said it would be tantamount to admitting something was wrong with the prior designs. Pathetic but it's happened before... and if I hadn't had a few Superbowl beers, I'd remember where:D

JCHannum
02-07-2010, 10:20 PM
An interesting writeup on the PRIUS brake problem and pending worldwide recall of the latest PRIUS model here;

http://www.timesonline.co.uk/tol/driving/article7018630.ece

What is unconscionable is that Totota has had a repair for the problem and has instituted it in the current production models but apparently has not as yet made it available to the public. This is the same approach taken with the shim sham flim flam, the initial shipment of shims went to the factory, not dealers.

This is definitely a software problem which possibly also affects the Lexus and other hybrids in the Toyota line. While it might not be the same problem as the sudden acceleration, it is a serious safety fault and it most definitely does not speak well of the reliability of Totota's software.

danlb
02-07-2010, 11:00 PM
Is the braking hullabaloo about this reported problem?


Regulators in the United States opened an investigation into the brakes of the 2010 Prius last week after complaints from drivers that the car can momentarily lose the ability to slow down when driven on an uneven surface.

It seems that it might be a no win situation. Use ABS when hitting bumps and it may free up the brakes till it senses traction has been restored. Without ABS, the bump will break your traction and you may lockup when it makes contact again.

Like I said before, I'm glad I don't have to do the engineering that goes into determining exactly what corrective action is taken and under what circumstances. BTW, it does not HAVE to be a software problem, but it sounds like they will be issuing a software fix.

Dan

Jeffw5555
02-08-2010, 12:03 AM
Nobody has mentioned the last "unintended acceleration" scare of 25 odd years ago affecting Audi's. The consensus today is that there was never any problem with the Audi systems, it was all purely "operator error".

That wasn't apparent at the height of the scare, and it nearly bankrupted Audi, all over people that couldn't figure out the difference between the brake and throttle pedals. I suspect the bulk of the problems Toyota is seeing today are mostly operator error, given history.

J Tiers
02-08-2010, 12:12 AM
It seems that it might be a no win situation. Use ABS when hitting bumps and it may free up the brakes till it senses traction has been restored. Without ABS, the bump will break your traction and you may lockup when it makes contact again.


ABS is a "think for you" system that may not always work right in the beginning.

I have mentioned the S10 ABS, which actually works decently on ice, but also triggers off on bumps with dry pavement. Mine has caused me to roll into intersections uncontrolled. A co-worker actually caused $2500 damage to his Lincoln Town Car when he rear-ended (and did not damage) a Geo Metro when his ABS triggered on dry pavement.

Both systems apparently turn off the brakes (effectively) for about 1 second after a bump. If there is more than one bump, you keep rolling and rolling uncontrolled.

Prius ABS may be different.

But I understand that the real problem is that there is a delay between the "handoff" of braking from the regenerative brakes to the regular frictional brakes, and that this apparently happens in ABS situations. I don't know how long a delay is involved. I can tell you that 1 second is a long time if you are trying to stop and avoid hitting a mother with a stroller who suddenly starts across the street......

Carld
02-08-2010, 12:36 AM
After googling the by wire systems now used and that will be used I definitely will not own a vehicle the has the steering, brakes, throttle or any combination there of controlled with a by wire system.

I will find out which vehicles are by wire and what is controlled and I will not ride in any of them.

I guess not to far off you will get in the vehicle and either tell it where to go or program the coordinates in and go for a ride as if you were in a taxi with no control over the vehicle at all.

Buck Rogers and Flash Gordon, here we come.

A.K. Boomer
02-08-2010, 01:15 AM
That makes perfect sense, why did they not do this years ago?

It DOES fail AK's "simplicity test", I assume.


JT, you act like this has been out for decades!

Why don't you give it a few years before you judge K?

I got something bombproof for you though -- A properly designed cable actuated throttle under the hood has a ZERO failure rate on many brand and model vehicles that have over a decade or two of track record ----- IF YOU NEVER HAVE A PROBLEM TO BEGIN WITH THEN THERE'S NOTHING TO TRY AND REMEDY.

So why not design this system and run with it,
it leaves the assembly line and rolls under a little sign that says "its in gods hands now"
and maybe there's 1 failure in 100 million vehicles due to someone spraying the car wash nozzle directly into the cable sheath and then going home on a winters night letting it freeze and then the next morning killing an entire school bus full of special kids, again, let it go, its a crazy little thing I like to call "perspective" ------- and while your trying to create situations that will do nothing more than cost more lives keep in mind that half the nation is driving this stuff that almost never ever fails and stuffing their vehicles into all kinds of living tissue while talking on their fuquing cell phones,
Fix the problems (we know how) - don't create new ones, and again - don't lose track of the perspective...

lazlo
02-08-2010, 02:21 AM
I got something bombproof for you though -- A properly designed cable actuated throttle under the hood has a ZERO failure rate on many brand and model vehicles that have over a decade or two of track record ----- IF YOU NEVER HAVE A PROBLEM TO BEGIN WITH THEN THERE'S NOTHING TO TRY AND REMEDY.

A wise man once said:


If you always do what you've always done,
You'll always get what you've always gotten.

A electronic throttle is the next natural evolution from the electronic ignition and electronic fuel injection: the ECU monitors and optimizes all the engine’s operations. It also allows coupling the electronic throttle to the cruise control, traction control, idle speed control and vehicle stability control systems.

That's the reason that F1 and GP2 racers (and high-end race bikes) use fly-by-wire throttles.

I just checked, and BMW introduced the electronic throttle back in 1988 in their 7 series, and they rolled it out across the rest of their vehicles over the next few years. So it's been road-tested for at least 22 years.

psomero
02-08-2010, 03:00 AM
http://jalopnik.com/5465002/toyota-recall-the-tsb-toyota-didnt-want-you-to-see/

Evan
02-08-2010, 04:49 AM
Just about every vehicle with an ECU already has a degree of computer authority over the throttle. The idle air bypass is completely under the control of the ECU and it has a surprising amount of throttle capability. It is enough to take the vehicle up to around 20 - 30 mph without touching the pedal if the bypass were to be commanded full open and the correct mixture maintained. It doesn't happen though because even if the bypass sticks open, which is common, the ECU won't command the correct mixture since it just isn't in the program.

There are many possible failure points in any computer and in anything less than a triple redundant system with a supervisor like the shuttle has, there are numerous single point failure modes. Computers rarely fail in a way that produces continued logical operation with illogical outputs. It is a contradiction in terms.

Most failures that produce completely wrong outputs are hardware failures and they aren't self correcting most of the time. Software failures will be detected by a watchdog timer that must be "touched" by the operating system on a very rigid schedule. If it isn't the watchdog will reboot the system immediately.

If the system still doesn't respond by periodically reseting the watchdog it will be restarted again. Depending on how advanced the system is this may only continue for a few seconds and if the system still doesn't interact with the watchdog it will be turned off and all the outputs will enter safe states.

Mission critical real time operating systems have been around for a long time, relatively speaking. Computers are used to control almost anything that has more than an on/off switch from your microwave oven to the traffic lights in most countries of the world.

These type of embedded systems are very well characterized and extremely reliable. The most popular control cpu in computer history is the 6502 which was originally developed by MOS Technology in the late 70s. It is still in production and it is estimated that the total number of units sold is between 5 and 10 BILLION cpus.

They are used in everything from heart defibrillators and pacemakers to wristwatches and cell phones. Computer control of critical systems is nothing new. It has been in widespread use since the early 1980's and has a very good track record.

oldtiffie
02-08-2010, 07:34 AM
Not much "fly by wire" here:
http://www.nytimes.com/2010/02/08/world/asia/08road.html?th&emc=th

Allan Waterfall
02-08-2010, 08:53 AM
"The car in front is a Toyota" definitely has a new meaning now....the throttle's stuck and the brakes don't work.:D

Allan

Carld
02-08-2010, 09:16 AM
Yes, and wait till they have full drive by wire. The ECU farts and now you can't steer or stop and the engine is wide open because the brake pedal is not connected to the brakes on the wheels, the steering wheel is not connected to the steering system and the foot throttle is just a potentiometer.

Google drive by wire.

J Tiers
02-08-2010, 10:06 AM
JT, you act like this has been out for decades!

Why don't you give it a few years before you judge K?

I got something bombproof for you though -- A properly designed cable actuated throttle under the hood has a ZERO failure rate on many brand and model vehicles that have over a decade or two of track record ----- IF YOU NEVER HAVE A PROBLEM TO BEGIN WITH THEN THERE'S NOTHING TO TRY AND REMEDY.

So why not design this system and run with it,
it leaves the assembly line and rolls under a little sign that says "its in gods hands now"


Everything has a first time........ "what's wrong with riding horses"?

You yourself, years ago, might have said " this newfangled throttle by a string system just isn't reliable, I won't drive in one a dem things.... what's wrong with pushrods?"

Besides, the cable actuated throttle does not have "zero failures", it has plenty. It can lock up just like the others. I've had problems with cable throttles too. It happened that my problem was a "won't open the throttle" issue, but it could as easily have been the reverse, since it just depends which end of the throttle pot goes bad.

A pushrod actuated system can fail also.

It is POSSIBLE to design a system, one which is NOT ridiculously expensive, that has sufficient redundancy and cross-checks to offer very good verifiable asfety.

In case you didn't know, there are UL standards for safety system software. They don't apply to cars.........yet. I expect that manufacturers will need to demonstrate software safety and other safeguards if they want to continue to make the vehicles more and more non-mechanical.
.
.
.
Now, to Evan's comments.....

merely using a computer to control safety systems is no guarantee of goodness.

There are ways to "do" high confidence software, and they start with the design process, and proceed thru the coding. it's expensive, it requires outside verification in many cases, and it's a pain. But when done, it works.

Most "computer problems" with standard systems will be due to one or more of the following causes (not a complete list).

1) unforseen normal input conditions which are not handled reliably

2) pure coding errors which create problems because a variable takes on a value that is erroneous due to initialization, buffer overflow, or a similar sort of implementation screwup.

3) A non-software issue such as EMI which is not handled with suitable recovery measures as far as it's effect on the program execution

4) electronic EMI issues, which produce bad values in sensors

5) mechanical type issues, such as sensor failure, wire breaks, etc, which produce unforseen abnormal input conditions that the software does not correctly handle.

6) non-mechanical interface errors, which produce erroneous values, for instance by causing input conditioning amplifiers to reverse output state due to input overloads (can happen with some FET input op-amps, for instance), or bad voltage reference for sensors, etc, etc, etc.

Doing software to deal with all of these is not easy, but it probably should become required for all vehicles.

In fact, a standardized safety system computer used in ALL vehicles might be a decent idea if this sort of issue persists.

Evan
02-08-2010, 10:10 AM
Carl,

Computer hardware and software of the type used in an ECU is extremely reliable. I have never had an ECU fail in the many vehicles I have driven over the years. I have also never had the software fail although I have experience problems due to bad design. You cannot compare the reliability of a general purpose desktop computer running a complex multitasking operating system with the reliability of a task specific embedded controller. The software in a controller can be 100% validated for correctness as it is relatively simple and very limited in scope. All possible combinations of inputs and the resulting outputs are predictable. Internal safety systems ensure that outputs are kept correct or safed if correctness is compromised. If any part of the system fails it fails safe and the ECU switches to a reduced power "limp home" mode.

The idea that the ECU could somehow randomly command a wide open throttle may sound reasonable but only to those who are not familiar with the actual internal operation and programming of these units.

Evan
02-08-2010, 10:14 AM
Doing software to deal with all of these is not easy, but it probably should become required for all vehicles.


You jest of course. Those are basic design requirements for any ECU and are already the minimum standard manufacturers of the units must work to.

J Tiers
02-08-2010, 10:17 AM
You jest of course. Those are basic design requirements for any ECU and are already the minimum standard manufacturers of the units must work to.

I do not jest.

they do not do what you say is "required".

This is proven because there are software problems.

problems are caused by NOT dealing with the issues mentioned. Since there ARE problems, Toyota has admitted that, the process did NOT work.

Carld
02-08-2010, 10:31 AM
That's true Evan and JT has some good points too. The cars and pickups I have owned since the 1980's have had some sort of ECU control. I have not had an ECU fail and if any sensor or wiring failed it was not a driving issue. I understand that most if not all ECU's go to safe mode to allow you to drive at a slow speed to get help if something fails.

We used programmable computer controllers on the shrinker/expanders and they are on many industrial machines to control functions.

It is still scary to me when I read about the steering wheel, brake pedal and throttle pedal are only connected to a potentiometer in the drive by wire systems. I don't like the idea at all and will not buy one but unlike some people I don't care if others buy one.

There are those that will say I don't like it and I will stop you from doing/buying it to save you from yourself. It may be that they can and will build a safe drive by wire vehicle but I don't trust them to do it.

Look at Toyota, considered to be above reproach and building a very dependable car, and they got caught in their own trap and since about 2006-7 have refused to admit there is a problem.

I guess I am just to skeptical to completely trust manufacturers. Others can if you want to.

lazlo
02-08-2010, 10:35 AM
Yes, and wait till they have full drive by wire.

Carl, I mentioned two pages back -- my M3 is completely fly-by-wire. Brakes, throttle, steering, suspension, clutch, traction control.

Much of that is user-configurable: you can set the active suspension, acceleration, braking, traction control, and steering very stiff and responsive for the track, or make it very plush for driving your In-Laws around town :)

I turn down all the controls down when my Wife drives the car. With 420 HP, it's very easy to fishtail, so you can soften the accelerator so that even if you slam on the gas, it will gradually accelerate, and the ECU monitors the traction control, so if one of the tires starts slipping, it will let off the throttle.

More amusingly, when you put the car in Valet Mode, all the controls are configured for low performance, so you don't have a Ferris Bueller's Day Off :)

Most (all?) sports cars now have fly-by-wire throttles for awhile. The Corvette has had it since 1997.
So drive-by-wire has a long-standing success in both consumer vehicles and professional racing.

Here's the description of the original '97 Vette's electronic throttle control:


"Drive by wire systems allows for a faster throttle response, better control over throttle application when combined with traction control and ABS and eliminates the need for a separate cruise control module. the system basically consists of the accelerator pedal with the built in potentiometer (variation of voltage output with pedal position), this is known as the APP (Accelerator Pedal Position), the TACS (Throttle actuator Controller) module and then the Servomotor and throttle sensor on the throttle body.

The TPS on the throttle body is actually two sensors in one package, that has opposite degree of output voltages to the TAC module and PCM, and serves to "cross check" and provides feedback each other with the APP sensor. The APP sensor actually has three position sensors, #1 sensor sends an increasing voltage, while #2 and #3 sends a decreasing voltage but at a different rate. The program in the TAC has built in parameters to make sure the sensors are in agreement with each other to smoothly actuate the servo motor on the throttle body. The built in redundancy of the system allows for safe operation of the system in case of minor failures, and will reduce power and even completely shut down the engine in case of a hard failure. The TAC module also is in continuous communication with the pcm. the failure of one sensor will store a trouble code in the pcm and the system will continue to operate normally. Failure of two sensors will result in reduced power, while an unlikely failure of all systems, may command a complete engine shut down. "

vpt
02-08-2010, 10:51 AM
JUNK! Put a cable on the damn thing! Electronic components fail all the time!

A.K. Boomer
02-08-2010, 10:57 AM
A wise man once said:


If you always do what you've always done,
You'll always get what you've always gotten.

A electronic throttle is the next natural evolution from the electronic ignition and electronic fuel injection: the ECU monitors and optimizes all the engine’s operations. It also allows coupling the electronic throttle to the cruise control, traction control, idle speed control and vehicle stability control systems.

That's the reason that F1 and GP2 racers (and high-end race bikes) use fly-by-wire throttles.

I just checked, and BMW introduced the electronic throttle back in 1988 in their 7 series, and they rolled it out across the rest of their vehicles over the next few years. So it's been road-tested for at least 22 years.


Point taken Lazlo and JT - but - My 92 tercel has a cable operated TPS under the hood ------ I already have an electronic throttle as the TPS is monitored so many times a second by my ECU, Like I stated earlier --- Personally I find great comfort that my car takes the pure electronic factor out of the equation and also adds a mechanical failsafe ---- MY CABLE ALSO CONTROLS A THROTTLE PLATE.

It doesnt matter if my electronics "wig out" as when it comes to creating power it "takes two to tango" If one system fails me(fuel) I still have a firm grasp on another (air) How do you keep your fire breathing dragon under control?
This is common sense and when it comes to the saying "if you always do what you'v always done you'll always get what you'v always gotten" approach --- keep in mind that sometimes that's a good thing.

The track record of a properly designed cable operated throttle system is so good that its a non-issue and in fact in over 34 years of wrenching iv never seen a problem (seen plenty on the old V-dub bugs - but remember I stated "properly designed")
Were talking cars iv owned - a camry at 368,000 + with original cable and a CRX with an astonishing 392,000 that I sold and last I heard had over 420,000, THIS IS GOOD DESIGN.
What you you think that plastic friction pedal will be doing at those kind of miles? Do I need to put it in distance to the moon and back?

Iv been wrenching for many of decade fella's - the last few on Japanese -
To me the highest quality No-nonsense cars that they have built are in the 90's if I had to choose a decade.

I will admit Direct injection gas is very exciting as there's so many potential bennies - but just because you can build engines without a throttle plate doesn't mean you should, besides --- who wants to buy all those air filters all the time;) DGI can be designed to work with or without, What type of system would you feel more comfortable with?

Being a mechanic iv seen allot of things over the years, one of the best simple rules to live by when it comes to safety is that you don't have the Fox keeping an eye on the hen house, What this equates to in what where talking about is that you don't leave an engine full bore open throttle and then just add fuel electronically and include the failsafe ELECTRONICALLY,
I'll pull an example right off the top of my head -------- The system is installed on millions of vehicles and works perfectly for many years --- Till a totally what seems to be unrelated part starts acting up --- the vehicles regulator ------ the entire system goes into overvoltage including the ECU,
Care to pull a straw at what part of the ECU shoots craps first?
Me neither ------------ Hmmmm -- cave man cable lookin pretty good right now huh --- uhhh --- hmmmm...

Carld
02-08-2010, 10:59 AM
I understand all of that but I still don't like the idea that everything is controled with potentiometers and NO direct manual physical link to the steering, brakes and throttle. I have a fair grasp of how they are doing it from the search I did but I don't approve of it for me.

If I am driving I want to physically steer and brake the car, I don't want a computer doing it. If something happens to the drive by wire and the steering fails your in deep dodo and stuff fails, look at Toyota. I just don't like it. I would rather dodge someones failed vehicle than be in the failed vehicle.

I don't mind you having one or anyone having one, I don't want one or ride in one.

JCHannum
02-08-2010, 11:04 AM
Any technology advance will come with growing pains. Engine management systems are generally a benefit, and driver controls can be an advantage over the "old" ways in added safety and control. The problem comes in development and application.

The problem that I have with Toyota is in their handling of the situation. They apparently have several problems throughout their product line. This points to an overall deficiency in their manufacturing system. It is either poor design, poor testing and evaluation of design before placing it into production, poor quality control, or some combination af all three.

Add to this, they do not respond in a timely manner, pointing in other directions before admitting a problem exists and then dragging their heels before implementing a fix. They then install the fix at the factory first, leaving their customers on the road with unsafe vehicles. This is wrong.

Robert's examples of the German manufacturers' systems and their safeguards show that the systems can be made to work reliably. The CR report has no German manufacturers listed.

JCHannum
02-08-2010, 08:54 PM
Toyota dealers respond to news stories on the safety problems by pulling their ads from ABC TV. Now there's a real proactive method of dealing with the situation.

http://abcnews.go.com/Blotter/toyota-dealers-pull-abc-tv-ads-anger-excessive/story?id=9776474

lazlo
02-08-2010, 09:34 PM
Toyota dealers respond to news stories on the safety problems by pulling their ads from ABC TV. Now there's a real proactive method of dealing with the situation.

http://abcnews.go.com/Blotter/toyota-dealers-pull-abc-tv-ads-anger-excessive/story?id=9776474

From the comments to Jim's video, here is Toyota's video describing their electronic throttle:

http://www.toyota.com/recall/videos/electronicthrottlecontrol.html

Based on comments from Toyota in the video Jim linked, the Prius, at least, suffers from a software problem that Toyota says was already corrected on models being built right now.

The Camry and other model apparently suffer from a different issue (at least, according to Toyota's site): floor mat entrapment (reminiscent of the '86 Audi accelerator pedal recall):

http://www.toyota.com/recall/videos/floormatentrapment.html

J Tiers
02-09-2010, 12:25 AM
Dunno about anyone else, but when driving, I relay very much on tactile, and even audible feedback from the machine.... I want to feel how the steering responds, that's one way I know what the road is like, slippery, or Ok.... I want to feel the braking effort vs the deceleration, etc, etc. I listen to the engine and shift on that basis......... I like a stiff suspension, I can feel the road character through it. In other words, I am apparently a dinosaur, or maybe some one-celled creature, as far as driving is concerned.

I have driven some vehicles, rentals, which were horrible....... So quiet, so "insulated" from the "driving experience"......... I find it hard to understand how drivers of these "snoozemobiles" can stay awake.

There was no audible feedback, the steering had little force feedback, the suspension was like a soft pillow, the automatic tranny did things when it pleased.... nasty. Like driving a padded cell. I wanted to roll down the window to get some idea of what was going on.

I guess I will have to drive cheaper cars..... they have still had more of the things I like...... but that is changing too.

winchman
02-09-2010, 02:13 AM
A 30 second spot that aired during the Super Bowl on CBS TV, at a reported cost of $3 million, dealt entirely the massive recall of almost 9 million cars because of safety issues surrounding sudden acceleration. A female announcer said,

"Your Toyota dealers is focused on the safety of their customers."

From: http://abcnews.go.com/Blotter/toyota-dealers-pull-abc-tv-ads-anger-excessive/story?id=9776474&page=2

It's hard to have confidence in their software when their ad has a glaring grammatical error. :D

MrSleepy
02-09-2010, 07:30 AM
On the news this morning (BBC)..

They started with a story of a Boeing 777 that had complete engine failure and had managed to avert disaster by crash landing short of the runway (flaps off,just managed to speed up enough).
They then praised Boeing for coming up with a new heat exchanger to avoid the problem of the moisture in the fuel freezing solid and causing engine failure..Now fitted over two years to all other 777s with RR engines
Well Done Boeing...

They then followed with the Toyota story of Prius brake/software glitches and throttle pedal problems and woe and woe and so on...
Bad Toyota for trying to fix problems


What a difference...


Rob

J Tiers
02-09-2010, 10:15 AM
Bad Toyota for trying to fix problems


What a difference...


Rob

Maybe the years-long history of Toyota denial and stalling before reluctantly and dragging their feet, they finally did a recall has something to do with it.......

Too_Many_Tools
02-09-2010, 07:51 PM
FYI...

TMT

Drivers, cars are ill-equipped when panic sets in
By DEE-ANN DURBIN, AP Auto Writer Dee-ann Durbin, Ap Auto Writer
56 mins ago

DETROIT – You're driving down the highway and suddenly your car starts accelerating on its own. Knuckles white, going from 60 to 90 miles an hour in a couple of seconds, you do what comes naturally — hit the brakes. But what if the car keeps going?

There are options: Put the car in neutral, or in park, or switch off the ignition. But experts say those choices would be almost impossible for most drivers to consider when they're in a panic, because frightened people often can't remember even simple steps to protect themselves. That — coupled with increasingly complicated gadgetry — makes cars a dangerous place to be when you're facing an unexpected situation.

"You're stamping on the brakes and your attention is going to be focused on where you're going and steering. There's no cognitive space left to think of alternatives," said Dr. Boadie Dunlop, a psychiatrist and director of the Mood and Anxiety Program at Emory University. "To do something that's not natural, such as turning off the engine, is just not going to come to mind."

Toyota Motor Corp. said Tuesday it is recalling about 437,000 Prius and other hybrid vehicles worldwide to fix a problem with brakes that are momentarily unresponsive in certain driving conditions.

That follows the automaker's recent recall of 5 million vehicles because of reports of unintended acceleration, and it's changing the gas pedals to prevent floor mats from jamming them. But complaints about unwanted acceleration in Toyota vehicles go back at least to 2003, according to U.S. government filings.

The issue gained new urgency last August, when a high-speed crash near San Diego killed an off-duty California highway patrol officer and three family members. The officer's loaner Lexus ES350 reached speeds of more than 120 mph, struck an SUV, launched off an embankment, rolled several times and burst into flames. The family frantically called 911 from the car, telling the dispatcher the pedal was stuck and they couldn't stop.

It's not known what exact steps the officer took in that case, but Dunlop said in such a situation, the brain can't handle all the information it's getting.

"When people are in an intensely fearful situation, their ability to problem-solve is greatly diminished," he said.

Venkat Thannir had his own brush with panic a few months ago. The 48-year-old college instructor from South Carolina was pulling his 2010 Toyota Camry out of a Burger King parking lot when it sped up without warning. He panicked for several seconds before pushing hard on the brake pedal and stopping the car.

"The vehicle was out of control," he said. "If I was not in a parking lot, it could have been a whole different story."

Thannir never figured out exactly what happened, but believes the pedal was defective, since he considers himself a safe driver. He plans to get the gas pedal repaired soon. In the meantime, he feels safe driving the vehicle for now.

Drivers have an array of safety features, including push-button stop in some cars. But the lack of standardization for those features further hinders peoples' ability to react to unexpected situations, since they vary from vehicle to vehicle, according to Paul Green, a research professor at the University of Michigan Transportation Research Institute.

Consumer Reports has criticized Toyota for the push-button ignition in Toyota and Lexus vehicles, which requires drivers to hold down the button for three seconds to turn off the vehicle in an emergency. Drivers of Cadillacs, Nissans and Infinitis can shut off the engines by pushing the button more than once.

"The design solution is to make them all work the same way," Green said.

Green said there's also been little research into the way safety features are laid out in the car. Is it easy to reach down and put the car in neutral? Should neutral be in a different order on the shifter so it's faster or easier to act? With push buttons, he said, one of the biggest concerns was whether children would be able to reach over and press them, not whether they were intuitive for drivers to use in an emergency.

Green said vehicles are getting so complex that the extent to which drivers can understand their cars is diminishing. In one recent analysis, the institute projected that the owner's manual and navigation manual for a luxury vehicle will grow to 1,000 pages over the next decade.

"Can you conceive of a person reading all this stuff and remembering all of it?" he said.

In the meantime, prepare yourself. Peter Norton, an associate professor of psychology at the University of Houston, said drivers should sit in their cars and go over the steps they could take in an unexpected situation. It's the same reason military personnel practice simulated battles or flight attendants repeat safety instructions on every flight.

"It's most helpful for a person, when you do go into panic mode, to resort to a natural tendency," he said.

"If you practice something over and over, that will be the thing that happens."

___

Associated Press Writer Page Ivey contributed to this report from Columbia, S.C.

Evan
02-09-2010, 09:18 PM
"You're stamping on the brakes and your attention is going to be focused on where you're going and steering. There's no cognitive space left to think of alternatives," said Dr. Boadie Dunlop, a psychiatrist and director of the Mood and Anxiety Program at Emory University. "To do something that's not natural, such as turning off the engine, is just not going to come to mind."



Nonsense. I had a vehicle where the floor mat would routinely shift forward and sometimes catch the gas pedal in the down position. When that happened I would reach down with my left hand and pull it back. It was a complete non incident the the few times it happened.

I would like to know why Ford hasn't recalled most of their fleet for cracking spokes in their alloy wheels. It has been a problem for more than 15 years and every year more people die because of it. My oldest and best friend's daughter and her boyfriend were killed in a single vehicle accident when the right front wheel on their Aerostar broke off and the vehicle tumbled end over end down the middle of the road. I helped bury her. There are numerous reports of this problem and it affects nearly every model in the Ford lineup. So far the only recall issued is for the Crown Victoria police crusiers. I guess it isn't good press to kill cops but the ordinary public isn't important.

J Tiers
02-10-2010, 12:33 AM
I guess it isn't good press to kill cops but the ordinary public isn't important.

You've got it, Jack.

There's plenty more of us...... no need to worry. :rolleyes:

saltmine
02-10-2010, 01:34 AM
Before I retired from my fleet job, in 2006, you'd be horrified at the number of serious and sometimes dangerous recalls we had to deal with on Ford Crown Victorias. After seeing how poorly these cars are engineered, I wonder why police agencies all over the US keep buying them. Of course, some agencies bought Dodges, which are measurably worse. Of course, most fleet managers are functional idiots, anyway. Why should I be surprised?

JTToner
02-10-2010, 01:53 PM
Saltmine,

A few years ago both Crown Vics and Chevy Caprice Classics (full size Impalas) were available and many agencies used one or the other or a mix of both. When GM s-canned the full size vehicles to focus on building "golf carts", it left only the Crown Vic and the Merc Gran Marquis. Recently, I've seen some agencies using Dodge Chargers. One difficulty agencies face is finding a vehicle that can be "caged" and accommodate people larger than dwarf in the rear seat. Even our Crown Vics are tight in the back seat and tallish men may have to sit sideways. That's why most agencies still utilize Crown Vics. As to the quality and/or engineering issues, help me out with that, I'm not aware of them and since I drive or ride in one every day on the job, I'd like to know what I should be alert to. Ours gets driven "vigorously" and we've been fortunate not to have any failures, catastrophic or otherwise.