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aostling
07-07-2009, 01:04 PM
Subaru has replaced the gearbox in its non-turbo boxer engine with a variable-pulley CVT. It appears to use a tension belt between the pulleys: http://www.subaru.com/engineering/transmission.html.

The CVTs in the Saturn Vue, the Honda Civic, and many other cars use a van Doorne push belt (illustrated here http://auto.howstuffworks.com/cvt2.htm) between the pulleys.

I thought the push belt (which is rather counter-intuitive) was invented to solve a problem with tension belts. What's changed?

http://i168.photobucket.com/albums/u183/aostling/cvt.jpg

winchman
07-08-2009, 06:34 AM
You're right, that looks like a tension belt. Knowing Subaru, I'm sure they have a good reason for using it.

That cutaway of the Subaru CVT doesn't look like it's been simplified very much. It's hard to tell which shaft the lower pulley is attached to. Any idea what the white/beige thing is that's riding on the belt?

I can see how the push belt works, and it looks like the advantage is a larger contact area with less relative motion between the segments. Either one seems to fall into the category of "proven technology".

I recently drove a Nissan Altima with the CVT. I don't know which type belt they use, but the performance was flawless.

The experience was only marred by the stupid salesman who drove the car for the first part of the test drive. He was obsessed with the "manual shift" mode of the CVT, and he over-revved the cold engine several times showing it off. What a total doofus!!

Roger

Circlip
07-08-2009, 08:49 AM
Ells Belles, Sorhubarb have re-invented the Daf Daffydildo.

Does this one go just as fast in reverse as the original????

Regards Ian.

lazlo
07-08-2009, 09:27 AM
Jeez, Subaru has re-discovered the Reeve's Drive.

Is there a plastic bushing you need to replace on a regular basis? :D

A.K. Boomer
07-08-2009, 10:40 AM
Just when you thought Subie's drivetrain couldn't get any worse,
They are by far the most inefficient drivetrain of the Japanese auto makers with all their 90 degree conversions and now they've added the magical frictional qualities of the CVT along with a dork converter ---- sweet:rolleyes:

Lets just hope the subie engineer's got their act together with a nice sized trans cooler this time cuz that puppies gonna be running its fluid through the "high speed blend mode" all the time, yes, even with a dork conv. lockout.

What's the sales pitch on that thing anyways - "now you can waste fuel while being bored"
Or ----------- "CVT's - the next best thing to staying home.":p

aostling
07-08-2009, 12:09 PM
What's the sales pitch on that thing anyways - "now you can waste fuel while being bored"


According to the article in Drive (the quarterly magazine sent to Subaru owners), the benefits of the new CVT are:


(1) Improved fuel efficiency, due to the engine spending more time in its optimal power range.

(2) No gear hunting when driving uphill.

(3) More passenger leg room resulting from the elimination of the gearbox.

lazlo
07-08-2009, 04:23 PM
the benefits of the new CVT are:

[indent](1) Improved fuel efficiency, due to the engine spending more time in its optimal power range.

Reeve's Drives are not very efficient -- the Bridgeport Vari-speed head has a 2HP motor, and the step pulley version has a 1 1/2 HP motor. Same deal with my Clausing lathe (which has a hydraulically operated Reeve's): 2 HP motor, and the step pulley version has a 1 1/2 HP motor.

If you've ever made the mistake of putting your hand on the variable-width sheave on a CVT after it's been running for awhile, they get really hot.

pcarpenter
07-08-2009, 04:35 PM
They've been using similar drives in snowmobiles for decades and in ATV's for the last 20 years or so. Inefficient? The belt drive system in my ATV gets pretty warm. However, a "regular" automatic transmission runs fluid at a couple hundred degrees through a radiator to remove all the heat it makes. If its heat, it's not motion, so by definition, that's a lot of ineficciency.

As opposed to a Reeve's type drive where the user controls the spacing of one of the sets of sheaves to control speed, the typical CVT uses flyweights and resistant springs to establish a typical acceleration curve. The spacing of the two sets of sheaves is continuously changing during acceleration. This the side effect of allowing the engineers to keep the engine in its "power band" all the time....so there's where you gain efficiency.

Paul

lazlo
07-08-2009, 04:48 PM
They've been using similar drives in snowmobiles for decades and in ATV's for the last 20 years or so. Inefficient? The belt drive system in my ATV gets pretty warm. However, a "regular" automatic transmission runs fluid at a couple hundred degrees through a radiator to remove all the heat it makes.

Sure, but a traditional automatic transmission is not efficient either, because of the torque converter. Like you say, the heat exchanger is dumping waste heat from the fluid coupling.

GKman
07-08-2009, 04:52 PM
Reeve's Drives are not very efficient -- the Bridgeport Vari-speed head has a 2HP motor, and the step pulley version has a 1 1/2 HP motor. Same deal with my Clausing lathe (which has a hydraulically operated Reeve's): 2 HP motor, and the step pulley version has a 1 1/2 HP motor.

If you've ever made the mistake of putting your hand on the variable-width sheave on a CVT after it's been running for awhile, they get really hot.

One tenth of a horsepower = 75 watts. Put your hand on a 75 watt light bulb after it has been running for a while and see which is hotter.

saltmine
07-08-2009, 05:02 PM
CVT's work great on things like snowmobiles, where you have enough power not to worry about efficiency or fuel economy.
When I worked for Ford, we had the Mazda Tribute Hybrids (prototypes of the Ford Escape hybrid) for testing at the proving ground. They all had CVT transmissions. Acceleration was leisurely, fuel economy was in the low 18's and they messed up constantly. About that time, Ford was offering CVT 's in the Ford 500 and they soon earned the nickname of "Ghost Shifters". Technicians were going crazy trying to diagnose the sometimes erratic and mysterious antics of the CVT. I found it amusing because the alternate transmission was the six-speed automatic built by none other than GM's Hydromatic division.

True, Lazlo. they do build up considerable heat in the torque converter, but modern auto transmissions are equipped with torque converter clutches, which eliminate any heat buildup in the converter by locking up mechanically,
like a "direct drive"...One nice thing about torque converter clutches....they allow an automatic to get the same or better fuel economy than a manual transmission.

pcarpenter
07-08-2009, 05:02 PM
Sure, but a traditional automatic transmission is not efficient either, because of the torque converter. Like you say, the heat exchanger is dumping waste heat from the fluid coupling.

That was my point. I was responding to Boomer's comment about how the friction of a belt *added* inefficiency. As compared to what? A traditional automatic which is *horribly* inefficient as evidenced by the heat load being high enough that it requires a radiator to remove heat from the transmission?

I think it would require some careful analysis to know for sure the real difference in efficiency, but CVT's are air cooled as far as I know, and some like the one in my ATV are even a closed system (mostly closed with only a tiny vent for pressure changes). If it tells you anything, the belt housing is plastic.

They are a neat system in that it requires no control other than throttle application. All control is at the input, and the load seen by the engine is much closer to constant than nearly any other system. The weak link is the belt. The ones used in snowmobiles and ATV's are highly tunable as well. You have both a primary and secondary clutch (input side and output side) and you can change the spring rate for either as well as the flyweights and their profile on the primary clutch to produce different acceleration curves. I have a kit in mine that allowed for much faster lockup at low speeds. They tend to be mushy on the front end to allow the engine to get up into its power band quickly. Given plenty of engine torque, its actually desireable when you are crawling slowly to get the belt grab much tighter, sooner. This makes for less heat and longer belt life.

Paul

pcarpenter
07-08-2009, 05:07 PM
One tenth of a horsepower = 75 watts. Put your hand on a 75 watt light bulb after it has been running for a while and see which is hotter.

You are comparing a filament which is almost 100 percent inefficient to a transmission. That filament is heating a thin glass shell with almost no mass. Try heating a transmission to 200+ degrees (Fahrenheit) with a 75 watt lightbulb. Trust me, an automatic transmission is wasting well more than 1/10th of a horsepower.

Paul

A.K. Boomer
07-09-2009, 09:39 AM
According to the article in Drive (the quarterly magazine sent to Subaru owners), the benefits of the new CVT are:


(1) Improved fuel efficiency, due to the engine spending more time in its optimal power range.

(2) No gear hunting when driving uphill.

(3) More passenger leg room resulting from the elimination of the gearbox.



Those guys are hillbillies --- They may be right if its an archaic engine with a hillbilly behind the wheel who doesnt know how to drive for optimum efficiency,
But now we have things like variable valve timing and duration, honda nissan and yodertoy all have proven dependable units that have been in production vehicles for quite sometime now, their matched to the transmissions to fill in the gaps far past the high and low shift points (high and low shift points when someone is driving for efficiency) and therefore have made the quest for the CVT all but obsolete. Why not take care of the problem where it originates? the engine, then you can run a free flowing drivetrain and surpass anything a CVT can do... common sense is a wonderful thing.

As far as the no gear hunting when going up hill, I don't "hunt for gears" --- I use the appropriate one for the task at hand and get the job done, If I happen to be in an automatic and the speed I want is close to the shift points causing it to seek then I use it manually and once again don't "hunt" -- just use the appropriate one, Please people - stop trying to take the last little crumb of thinking out of my driving or I really will fall asleep at the wheel (more times than I already do)

And taking a look at that trans and comparing the bell-housing to the length -- there's no more room for "passengers" It doesnt eliminate a gear box, it still is and its not only just as big, its got a higher hump in the middle, Junk.

A.K. Boomer
07-09-2009, 09:58 AM
That was my point. I was responding to Boomer's comment about how the friction of a belt *added* inefficiency. As compared to what? A traditional automatic which is *horribly* inefficient as evidenced by the heat load being high enough that it requires a radiator to remove heat from the transmission?



Paul




Actually that's why I threw in the clause;

"Lets just hope the subie engineer's got their act together with a nice sized trans cooler this time cuz that puppies gonna be running its fluid through the "high speed blend mode" all the time, yes, even with a dork conv. lockout."

Any automatic worth its weight in shop rags is going to have a lock out torque converter, So how much of a difference does this make? depends on design and the mode the trans is in but here's a little cue for you, a properly designed automatic can achieve better fuel economy than a manual trans on the highway, The reason for this is the fact that todays automatics are basically a manual trans when the torque converter locks out at highways speeds, Now couple that with two other factors that outdue the manual, one is the auto runs in thinner fluid --- the second is that it uses a superior design in gear loading -- its called the planetary system and instead of pushing gears into bearings and trying to force them apart they equally load them in at least three 120 degree directions, This is a great way of transmitting power, this is why you can go to www.fueleconomy.gov and research certain vehicles and actually verify that certain autos get 1 or 2 mpg's better than their manual options.
Like my dad used to say when pointing to his head and tapping on it with his finger "kidneys"...

aostling
07-09-2009, 12:47 PM
Please people - stop trying to take the last little crumb of thinking out of my driving

Tomorrow I embark on a 5,000 mile drive in the Forester, to the Bay Area, thence to Seattle, and back to Phoenix via Montana and Yellowstone. These miles will be 95% on cruise control so the only "thinking" I anticipate is deciding where to steer.

My only quibble with the powertrain is that it is full-time 4WD. I don't need this, and as discussed on an earlier post this robs me of a few MPG. The directionality of the power transfer all follows as a consequence of the longitudinal boxer engine. The inefficiency is a concern, but the engine's low c.g. is an asset which contributes to superb handling.

A.K. Boomer
07-10-2009, 11:43 AM
Tomorrow I embark on a 5,000 mile drive in the Forester, to the Bay Area, thence to Seattle, and back to Phoenix via Montana and Yellowstone. These miles will be 95% on cruise control so the only "thinking" I anticipate is deciding where to steer.

You might want to put some thought process into braking too - simulated test have shown that Cruise controls cause drastic time delay reactions in braking response -- not only that -- they have proven total brake pedal mis-fires due to people not even knowing where their right foot is should something arise therefore either falling short or overshooting the brake pedal,
So many times I here people say "yeah but I can drive almost twice as far with my cruise control"
Now humor me and ask yourself "why" Do you think its the little throttle spring thats wearing you out? cant be - about half the effort is overcome with just the weight of your foot!
What it is - is just another apparatus that removes the driver from what he or she should be doing - driving - the fact is - is if the right foot is already engaged in an operation it is far more up to the task of immediate response to engage in another - not only that, while its being engaged it knows exactly where it at therefore it knows exactly where the brake pedal is at also - due to the fact that Just about all of us (unless your one of those freaks who drives an auto and brakes with their left foot) use their right foot to both work the throttle and brake pedal this is important information.
Iv used cruises a few times but always seem to turn them off after a little while because I dont like the "feeling".
You see - it doesnt really matter if they can make me drive twice as far if im doing it in some kind of zombie trance while doing it:p To each their own but I will add that CC's also make sleeping at the wheel more of a possibility by removing the little bit of thinking involved that we should try to keep, furthermore ---- CC's insure that when the car does leave the road (or paste a parked car on the side there-of) that is does so at speed...
Not so with typical vehicle accel pedals as they take a slight energy to compress, also what's been proven is sometimes the de-accel when falling asleep will wake a driver up and totally avoid the accident in the first place.


My only quibble with the powertrain is that it is full-time 4WD. I don't need this, and as discussed on an earlier post this robs me of a few MPG. The directionality of the power transfer all follows as a consequence of the longitudinal boxer engine. The inefficiency is a concern, but the engine's low c.g. is an asset which contributes to superb handling.

Yes subies drivtrains suck for efficiency, the two 90 degree conversions take their toll in design and also having to churn up hypoid fluid whilst the standard models viscous coupling further reduces power transmission due to being worked even on the highway,
And subie's claim to a low CG is ludicrous due to the fact that the entire engine drivetrain and body is much higher then a standard vehicles -- Subies don't have "superb handing", actually subies are roll pigs. but that's the compromise for being able to go off road once in awhile, Now they might have "superb handing" when compared to a typical SUV - but lets keep things in perspective --------------------- that's not saying much...

Pick up a aluminum Honda or toyota cylinder head with a couple fingers and imagine it on top of a subie engine thats about 4" lower than yours -- believe me thats not going to tip your car over around a turn, but moving all the sprung weight of the vehicle 4" more above the axle line will ---------- once again --- "kidneys".

aostling
07-10-2009, 09:07 PM
You might want to put some thought process into braking too - simulated test have shown that Cruise controls cause drastic time delay reactions in braking response".

I've just come to rest in a motel in Thousand Oaks, after negotiating 160 miles of LA freeways starting in Indio on the eastern edge of the sprawl. I use cruise control because of the comfortable foot position (flat on the floor) it affords. Braking response is never a problem since I allow about twice the recommended spacing behind the leading vehicle. I encountered a stoppage on the Hollywood Freeway and braked for it. A quick check in the rearview showed the car behind me was surprised and headed for the shoulder so I had to ease off and get as close to the car ahead as feasible.

I got gas in Thousand Palms, and passed an exit for Twenty-nine Palms. Southern California has so many communities they evidently run out of good names, so just count the trees and call it done.

A.K. Boomer
07-10-2009, 10:20 PM
Sorry Al, im just really getting burnt out on things that take people away from doing what their supposed to be doing while driving - and that would be driving.

I can just imagine half the populous driving their CVT's 10mph over the speed limit with the cruise on while talking on their cell phones and applying make-up,
Whens enough enough bro? how many people have to die? why cant we sic MADD on these idiots too? theve far surpassed what the godamn drunks are doing.

Whats next -- do we get to eat bon-bons too while watching our favorite show on the windshield? Lets get the common sense back a little ehh.

bob_s
07-10-2009, 10:53 PM
My only quibble with the powertrain is that it is full-time 4WD. I don't need this, and as discussed on an earlier post this robs me of a few MPG.

So was the sales guy holding a gun to your head ... or ... were you thinking about all the snow you were going to have to drive through in Phoenix in the winter???

danlb
07-10-2009, 11:17 PM
---------- once again --- "kidneys".


Ummm. You do realize that is the punchline to a joke, right? And that the person in the joke who says that is a moron? Just thought I'd mention it. :)


I'm not sure how we got onto cruise control from the technical merits of push belts. Using cruise on some cars is an excellent way to get better gas mileage. The CC that is integrated into the engine control software avoids the surges that most people tend to cause. Once you get used to it it works quite nicely, and even helps avoid tailgating.

I'm delighted find out about push belts. It's a neat technology. Thanks for mentioning it.

Dan

aostling
07-10-2009, 11:39 PM
So was the sales guy holding a gun to your head


Sales guy? I don't talk to auto salesmen. The last one was the guy who sold me a Stanza in 1981. I'm glad online sales are possible these days.

I'm on my sixth car, not so many considering that today is my 68th birthday.

lazlo
07-10-2009, 11:46 PM
I'm on my sixth car, not so many considering that today is my 68th birthday.

Happy Birthday Allan :)

Doozer
07-11-2009, 11:56 AM
Reeves drives are very inefficient. I had an engine on a mini-bike that was putting out about 9hp. It had a Comet TAV30 Reeves type drive. Top speed was about 27 mph. It felt like the engine was really laboring and I was not getting it rev or getting any real speed. I removed the belt and variable pitch pulleys, and installed a centrifugal clutch and chain sprocket. The bike was of course slower on the take off, but top speed was now 42 mph. The reeves was eating my hard earned horsepower. Now I know why Jap bikes use gear transmissions integral to the engine. Why don't snow mobiles use motorcycle engines instead of the dorky reeves drives? Those sleds go over 100 mph now. Imagine what they would do without that power robbing belt?!?

--Doozer

A.K. Boomer
07-11-2009, 12:05 PM
Ummm. You do realize that is the punchline to a joke, right? And that the person in the joke who says that is a moron? Just thought I'd mention it. :)

Dude -- your an idiot, You need to re-read, It was my Dads way of
getting a point across without insulting somebody - he was so kind hearted old school that after he would show or tell someone the proper way of doing something (after they cobbled it up in some archaic fashion) he would remove the inferiority complex that they might have by pointing to the side of his head and saying "kidneys" the people would relax and realize he was actually on their side and just trying to help them learn, so in effect they would not only learn better - they would have a better time doing it.
So you see the effectiveness of the human mind when used in the proper manner - and in the way My Dad used it - it was genius.




I'm not sure how we got onto cruise control from the technical merits of push belts.
its a real simple thought process danb - the technical merits of push/pull belts are directly mentioned along with the CVT trans. and picture that led to the merits of the CVT itself that led to aostling stating that there's no gear hunting going up hill that led to me stating that I dont hunt for gears -- I just use them for the task at hand - and led to me stating "stop trying to take my thinking out of my driving" for me that led to aostling talking about his big trip with the cruise on that also led me to state about how cruises are yet one more proven devise that removes people from the task at hand and here we are full circle - comprendo? Now - if I can explain that in one short paragraph can you see how it can happen in a couple three pages of reply's ------- Goody for you - youv discovered how discussions evolve:rolleyes: (kidneys)


Using cruise on some cars is an excellent way to get better gas mileage. The CC that is integrated into the engine control software avoids the surges that most people tend to cause. Once you get used to it it works quite nicely, and even helps avoid tailgating.


And once again you totally mis-inform the board, all cars and trucks unless diesel or direct injection gas can eat it big time in fuel economy if the cruise control is used over an experienced driver that does not use one, where I live esp. cruises don't have the ability to self adapt for the situation, they are designed for one thing and one thing only and that's to keep the speed a constant --- BIG MISTAKE when going for optimum fuel economy

You see these two gauges in my "92" tercel;

http://i146.photobucket.com/albums/r249/AK_Boomer/DSC00393.jpg

One is a fuel/air mixture and the other is an exhaust pyrometer, Iv achieved 62.5 mpg out of a car that's rated 33 highway ( www.fueleconomy.gov ) And believe me I know exactly how I did it, Yes about half is me manipulating the air/fuel mix -- but the other half is just me paying attention to two critical factors and that is throttle position and air/fuel mix, at mild throttle applications the air/fuel mix remains a constant meaning it "stays put" in regards to where I run the potentiometer setting, but any slight hill or head wind gust or having a big rig slowly pass on the left side and plowing air at my front end and If I try to maintain the same speed I have to use more throttle to do so -- even with standard settings (which I still have with a click of my potentiometer button) and a totally normal air/fuel mixture I can watch the EGT's go up and if I push the throttle a little more then its like night and day -- the mixture goes to full rich ---------------- This is how every gas vehicle out there works unless its direct injection - this has to be or you will have a meltdown,
Cruises IMMEDIATELY throw the engine into this extra rich mode ALL the time due to being concerned about one thing and one thing only - constant speed - big mistake --- actually one of the best methods you can use for optimum fuel saving is the exact opposite of what the cruise control does --- find your optimum setting of throttle position with your foot and DON'T change it unless you absolutely have too, I find that im giving up about 5 mph on some small hills but that's ok because im not "tripping off the enrichment mode" and I just keep my foot in approximately the same position on the descent (or maybe lifting a little ) and not only recover the lost 5 mph but end up about 5 over, time wise it all works out and I also save much more fuel than if I were to charge the hill in full on enrichment.
This is how far you can go if your not some hillbilly just yappin your gums on the internet, this is how far you can take things when you get a grasp on the theory of operation --- if you get the theory of operation down you can do just about anything you want, and so to make you feel comfortable with the spanking youv just received - and in hopes that you might learn a thing or two ------- once again "kidneys" --- although I will readily admit that i lack the grace and tact that my father had - deal with it...


I'm delighted find out about push belts. It's a neat technology. Thanks for mentioning it.

Dan

Me too - I cant wait till they come out with one that i can use to stir paint with cuz iv got an old non- VS drill I want to put to good use still :rolleyes:

danlb
07-11-2009, 10:03 PM
Wow! It's been years since I was called an idiot on the internet by someone who does not understand contractions. Good for you AK. I hope it felt good.

For those that don't quite catch what AK is doing to get such great mileage, he's manually changing his air/fuel ratio based on guesses and intuition. His great mileage is at the cost of increase pollution, and it's probably hard on his car, but I'm sure that is of little concern or her would have mentioned it.

The over generalization that all a CC is designed to do is maintain speed is... well, faulty. In a modern car, the CC does not kick in the enrichment mode unless you are suddenly climbing a hill. It gradually changes speed, so smoothly that it's seldom noticeable.

In a really modern car, the gas pedal is not necessarily tied to the engine at all. Many are using 'fly by wire' technology. In my car, the gas pedal is used to suggest that you want more or less speed. The engine may or may not increase it's RPMs, but I get whatever speed I want and if I hold it steady I keep it within +- 0.5 mph. And I still get 45 while driving normally. I'd never again settle for a piece of crap like a 92 Tercel again.

But back on topic.

There are various types of CVT available now. Hydraulic, Variable Sheaves and Electric to name a few. Toyota's Prius makes one from a planetary gear setup. I like the way a CVT allows a smaller engine (in a car) to do the work of a larger one. Despite the losses of the CVT, the fact is that you don't have to put up with fixed gearing that is optimal at what, 5% or 10% of the possible speeds? Being able to stay in the power band means less peak power is needed. The downside, of course, is that (until recently) there were torque limitations on CVTs. Thus teh underpowered Subaru Justy.

I'd love to add variable speed to my old mill. This thread has inspired me to look into it more. Thanks!

Dan

A.K. Boomer
07-12-2009, 12:22 PM
Wow! It's been years since I was called an idiot on the internet by someone who does not understand contractions. Good for you AK. I hope it felt good.

It felt great --- I don't start with the name calling around here -- but I will finish it every single time, Once again you might want to go back and re-read to find out why your getting a spanking...


For those that don't quite catch what AK is doing to get such great mileage, he's manually changing his air/fuel ratio based on guesses and intuition. His great mileage is at the cost of increase pollution, and it's probably hard on his car, but I'm sure that is of little concern or her would have mentioned it.


It is of very little concern and its mostly due to the fact that you don't have a clue as to what your talking about, Iv set-up and tested cars and failed them or past them in emissions testing for DECADES, there's allot of misconceptions and lots of hillbillies like you who simply don't know how things work, My great mileage is a result of course of burning less fuel --- Which is the only way you can reduce greenhouse gas (CO2)
It's also directly related to hydrocarbons in the fact that the more completely I burn the fuel the less HC's are emitted and also the less the C. converter has to deal with it --- either way the fuel will be burnt - and that takes oxygen and the by-product is CO2 --- the difference is Your burning much more than I am just to apply heat to your Cat. converter while im using it to actually get work done (see 62.5 mpg)
Emissions is still a juggling act - NOx levels increase under optimum combustion pressures so we have EGR's to reduce this effect - my car is still equipped with both a cat. and a proper working EGR system even though I live where testing is not needed,
I have to add -- this isnt about a simple shop emissions test where the car is idling at normal operating temp and thats it, this is about real driving conditions, and by me avoiding the rich zone I am drastically reducing overall emissions plain and simple, There is one area where I have to be careful and thats cold morning warm ups - If I start the car in efficiency mode and let it warm up that way there's less fuel being burnt to pre-heat the cat and therefore unburnt HC are being emitted into the atmosphere -- but there's really not -- due to me having a potentiometer with a click button that puts the car on its original box stock single oxygen sensor mode -- so the cat heats up, and then I switch over to efficiency mode.
And If you want to try and use the parts per million scare tactic try someplace else - I could give a rats flying ass if my car pollutes ever so slightly more in PPM's than a caddy that's consuming 3 to 4 times the fuel (and air) while doing it. sit down.


The over generalization that all a CC is designed to do is maintain speed is... well, faulty. In a modern car, the CC does not kick in the enrichment mode unless you are suddenly climbing a hill. It gradually changes speed, so smoothly that it's seldom noticeable.

Its not faulty - its exactly what its designed for - it goes by one thing and one thing only - speed, that's why there's pick up coils on trannies and its why you glue magnets on drivshafts on the install kits -------- and a gradual change or an abrupt one does not matter one bit -- if the headwind is big enough or the hill is steep enough (by the way it doesnt take much at all) then you will surpass a predetermined power percentage and heat value of the engine running past a guided sensor controlled program that will induce full on enrichment --------- I don't by-pass this, my unique system I built wont allow it, I just stay out of the area all together and where the engine is running on minimum percentage power value (on the flats) I ween it into a leaner but still safe value by using EGT's as a guide.

In a really modern car, the gas pedal is not necessarily tied to the engine at all. Many are using 'fly by wire' technology. In my car, the gas pedal is used to suggest that you want more or less speed. The engine may or may not increase it's RPMs, but I get whatever speed I want and if I hold it steady I keep it within +- 0.5 mph. And I still get 45 while driving normally. I'd never again settle for a piece of crap like a 92 Tercel again.

Hello -- all gas pedals are "tied to the engine" It doesnt matter if a cable operates a potentiometer under the hood or it operates one right at the floor board ------- I hate to tell you this stymie but do you have any idea where those wires down by your foot eventually can be traced too:rolleyes:
And guess what -- when you get to know theory of operation you will realize that your piece of crap operates in the same basic manner as my piece of crap - unless like I stated way back if you have direct injection gas then the rules change.


But back on topic.

There are various types of CVT available now. Hydraulic, Variable Sheaves and Electric to name a few. Toyota's Prius makes one from a planetary gear setup. I like the way a CVT allows a smaller engine (in a car) to do the work of a larger one. Despite the losses of the CVT, the fact is that you don't have to put up with fixed gearing that is optimal at what, 5% or 10% of the possible speeds? Being able to stay in the power band means less peak power is needed. The downside, of course, is that (until recently) there were torque limitations on CVTs. Thus teh underpowered Subaru Justy.

I'd love to add variable speed to my old mill. This thread has inspired me to look into it more. Thanks!

Dan

Yodertoys prius is not a true CVT, its just a fixed geared planetary unit that is coupled to its engine side and motor side and uses electrical energies (and therefore torque and a predetermined speed) on its motor side to react to the speed of the engine side and come up with the proper ratio to deliver power to the cars drive wheels,
Basically the CVT Prius is always stuck in top gear so has no torque advantage from the engine while taking off, that's manipulated from the electric motor drive end of it.
True CVT's all operate on surfaces that are capable of a multitude of different ranges without actually being "fixed"
In doing this it takes frictional pressures to keep the system engaged, Yes units can be built to handle just about any torque application if the word "practical" is excluded ---------- CVT's still suck hind tit in the fact that they fall short of not being able to transmit no where near as much torque as their fixed gear competition (that's why in this original post Aostling stated that its only available on the non-turbo version)
At very best CVT's are patchwork for poor engine design as we now have all kinds of things that keep engines in the optimum operating rpm range due to the fact that the range has been drastically increased - therefore making the horsepower robbing, boring, piece of crap CVT all but obsolete except for the hillbillies that don't know any better and think its "kewl".

danlb
07-13-2009, 03:07 AM
I like it when people post things that point out the depth of their ignorance. I now know to ignore AK's posts about cars, pollution controls, grammar, interpersonal communications and electronics.

I'm pretty sure he knows about machining, but time will tell.

For the rest who might be reading this thread... If you run the car too lean, you starve the catalytic converter, rendering it ineffective.

Fly by wire tech is getting more and more common. The Prius uses an electronic steering system as well as a throttle that is totally computer controlled. This lets the computer minimize (somewhat) the actions that cause more pollution without benefit. It's really neat technology, and provides the smoothest cruise control I've ever used.

Dan

A.K. Boomer
07-13-2009, 10:12 AM
Danlb,,,,you can't add anything because you have nothing, like I stated earlier it doesnt matter if your controlling your computer from a cable that runs under the hood to a potentiometer or if your eliminating the cable and just running the potentiometer to the computer --- You can rig your engine controls any way you wish and you will still have to feed the power plant an extra rich mixture when climbing a hill unless you give up a certain power demand percentage ratio and keep it out of the enrichment mode,

As far as your comment about starving the cat. iv already covered that, its why I have a by-pass mode for cold mornings, With the ratio's I run this can only happen at idle and only on warm up, Get some kind of a system together before you go misleading the board -- I have one - 30 years of experience and a car thats fitted with all the instruments for proof, I cant even starve my cat at idle as it will only take an extra minute of two to catch up -------- but while driving - forget it, too much CFS going through pilgrim.
Once again -- learn some theory operation before you go yappin yer gums --
I dont care how "smooth" your cruise is - if the task at hand surpasses a per-determined percentage rating of the engines total output then you will pay the fiddler in enrichment to keep the tops of the pistons from having a meltdown ------ I STILL HAVE THIS SYSTEM ---- I just stay out of it and have the instruments to guide me, The other fact is - is that on the highway my cats working excellent due to not being oxygen deprived yet still having enough unburnt HC's going through to keep it nice and hot, the end result is a superior combustion and reduced emissions.

The other deranged thought process your going through is you call my car a piece of crap when it gets better mileage than yours :) Also when it has a much better track record (as far as in miles its already been to the moon and is heading on its way back) all of this and I bet I paid about what you pay for one of your monthly payments (my car cost me 300 usd)
Now --- lets talk piece of crap,
You have an inferior automobile from the start -- it has no real "track record" of proven dependability, and you took it in the shorts too boot ------- Let me ask you something Dan -- who owns the piece of crap:D
Fill in the blank; A _ _ _ _ and his money are soon parted :o
Logic sucks for you --- and reality bites don't it? sit down.