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  • Edwin Dirnbeck
    replied
    Originally posted by A.K. Boomer View Post
    I cannot speak for every system out there as there's allot of variations but know that most if not all have abandoned it,

    keep a closer eye on your air filter as you are pumping allot more CFM through it if your engine is "plateless"
    Yes,thank you. I have already changed the air filter and the cabin filter. They both looked pretty clean,we don't smoke or drive on dirt roads.It sure seems that the engine air filter and the catalytic converters would be doing extra work with a wide open throttle. Edwin Dirnbeck

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  • MattiJ
    replied
    Originally posted by strokersix View Post

    I don't understand why we don't just build diesels. This blending of the two does not make sense to me.
    Diesels have been extremely popular in Europe but now there is heavy decline on numbers. Latest emission standards are hard to fulfill and WV(+everyone else) software scams was the final nail in the coffin.
    Over 50% of sold passenger cars were diesels in here 10 years ago and diesels were even more popular in many other European countries than here in Finland.
    Last edited by MattiJ; 06-17-2019, 08:31 AM.

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  • J Tiers
    replied
    Diesel spills are not a big problem in enclosed spaces. Gasoline evaporates, and the vapor in air is actively explosive. Bad in a mine.

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  • Willy
    replied
    Diesel engines are the predominate choice of underground mining equipment power plants for a number of reasons that make sense to those that make money in such ventures. There is now a large assortment of industry approved diesel engines available. The list here of of diesel engines approved by Natural Resources Canada pretty much parallels that of the US and a number of other countries that share common safety goals that pertain to a large number of multinational companies.

    I think the major issue with the use of gasoline engines in this safety critical application is due to the fuel itself being more dangerous in it's raw form and the fact that diesel engines emit drastically lower levels of carbon monoxide, thus reducing ventilation requirements. It's all about dollars and cents boys and girls, as usual.

    Maybe I'm not using the right search criteria but try as i may I could not find a list of gasoline engines approved for underground mine use applications whether they be gassy or non-gassy mines.

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  • A.K. Boomer
    replied
    Originally posted by J Tiers View Post
    Diesels are dirty.... particulates, unburned fuel, black smoke if poorly adjusted, etc. They often stink, and the stuff they put out is highly carcinogenic.

    .

    yet just like a good barBQ if someone is generous enough to roll a little coal my way I just crank down the window and take it all in, I like the smell of diesel always have,,, pre-combustion or after,,, hate the smell of gas both burnt and un-burnt...

    side note and many moons ago, there was a local coal mining operation that used to use the only IC engine vehicles that were allowed into the mine - in fact I rebuilt many of engine for them - and they were not gassers,,, they were chop top wabbit diesel pick-ups to carry gear back and forth,,,

    for what it's worth they were the only vehicles that passed the "internal coal mining emissions" considered safe enough to breath the air...
    Last edited by A.K. Boomer; 06-16-2019, 11:58 PM.

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  • A.K. Boomer
    replied
    I will never "knock" a diesel for a passenger car, iv owned two silly wabbits that both achieved close to 50mpg dependably and did everything they were designed to do, my only regret is i did not get a turbo diesel Jetta - had the hots for one at the time but never got around to it cuz I entered the honda "CRX era" but that was fun and economical also... (way more fun than the wabbit's)

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  • J Tiers
    replied
    Diesels are dirty.... particulates, unburned fuel, black smoke if poorly adjusted, etc. They often stink, and the stuff they put out is highly carcinogenic.

    They are complex, tend to be heavy (Guiberson notwithstanding), and expensive.

    Fixing all that reduces the efficiency advantage they currently have by a chunk. And diesel has consistently been more expensive by volume than gas....more so than the mileage advantage.

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  • JRouche
    replied
    Originally posted by strokersix View Post
    I don't understand why we don't just build diesels. This blending of the two does not make sense to me.
    We tried that. Remember when they made a diesil cadillac or chevy.

    Hell no. O I want my small block chevy.

    I dont drive muck. My new car that is 5 years old has about 5700 miles. Yes, fifty seven hundred miles.

    I dont drive much. JR

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  • A.K. Boomer
    replied
    Originally posted by J Tiers View Post

    The true efficiency is the amount of energy extracted, compared to the energy content of the fuel to begin with.
    Now that level's the playing field - then it all comes down to engine operating principle and design...

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  • J Tiers
    replied
    Originally posted by A.K. Boomer View Post
    .....

    yes im familiar with Smokey Yunicks ceramic engines and such, iv just never heard anyone use that as the holy grail for judging that Gas is more efficient then Diesel, there's no reason you can't also create a diesel to run to extreme temps, i mean if you get to toss emissions out the window then so do I, I would think tie goes to the fuel with the greater BTU rating --? heat it up and burn it and see what you get...
    Never heard of SY's ceramic engines...... talking about research engines at universities etc. SY was a tinkerer... a smart tinkerer but not a researcher. probably the whole thing is moot, since the diesel is gradually having its present advantage legislated away, and gas engine technology is improving.

    if you are talking miles per gallon, or some such, you are off-base, like measuring liquid volume by wind speed........

    It is nearly meaningless, and a function ONLY of the stupid american habit of measuring chemicals by volume. At the very least, you would want to measure by mass, and in reality, you would want to measure fuel by net energy content of the amount sold, because THAT is what you are buying.

    The true efficiency is the amount of energy extracted, compared to the energy content of the fuel to begin with.

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  • A.K. Boomer
    replied
    This discussion does make me wonder about combustion chamber "hot spots" that were so dreaded for the old gassers as they could cause the fuel to go off under compression,,, so would not the answer for the new Dig's be creating one? as in an initial glow plug to help the engine start and then it sits there out in front of the injector nozzle glowing red hot waiting for it's next "spritz" of fuel,,,
    perhaps there is still an advantage to being able to control spark and injector timing and that's why it has not been done,


    these newer little engines are amazing - the honda CRV for example needed a NA 2.4 liter to push it around and now it's got a 1.5 turbo that's not only faster but has about 1/3rd better fuel economy... Before Dig's you would shoot yourself in the foot expecting to do better in economy by throwing a turbo charger on an engine, in fact why honda never used them...

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  • A.K. Boomer
    replied
    Originally posted by J Tiers View Post
    The engine may be at "full bore", but it still can take in no more air than the cylinder volume x the number of intake strokes, as modified by manifold pressure (higher if turbo,and including flow related pressure drops)....... and, it has to be stratified charge, because despite the crowing about "forget stoichiometric ratio", it still has to LOCALLY have the correct ratio, or it will not go "boom" (there are limits of flammability). That's nearly the definition of stratified charge, and I believe you said so yourself.......
    Your right technically it is the definition of a highly advanced stratified charged engine - but not to be confused with yesteryears, but we were comparing the old gassers to the new Dig's, and i used idle or mild load as an example,
    the old gassers do not even come close to filling up their chamber due to a throttle plate that is all but totally cutting off their air supply, the Dig's are taking in 10 fold if not 100 fold amount of air in comparison,,, this has NOTHING to do with engine displacement or turbo charging,,, one is restricted - the other is not, And yes you can "forget about stoichiometric ratio" as some kind of solid guideline throughout the engines range, unless you plan on including more flexible ratios of 60+:1

    , it's why I used idle and mild load as an initial example, even the old school stratified charge engines could only make mild gains in comparison... again were talking turbo charged engines with 14:1 compression ratio's --- that's incredible... and they are now the dominant force in production vehicles... it's what everyone is going to...



    As for no throttle plate, that has nothing whatever to do with it. Puts only enough fuel in to equal the power needed.... if it put in more, the engine would accelerate until the load DID equal the fuel burn power (at efficiency). Works as well as a throttle. Better, actually. Air flow is constant at a given rpm, but fuel burn is related to power needed at that rpm.
    maybe this will help , the old gassers were at the mercy of controlling their flame front and burn rate by using mixture ratios's , the Dig's get to function more like diesels and are "somewhat" IMMUNE to this fact, they control their flame front and burn rate with injection...

    Carnot efficiency is related to the difference in temperature between starting state, and final state of the "working fluid" in the energy extraction process (power stroke, here), so long as it is used efficiently, and assuming no loss to cylinder walls etc. That's the very very short story, and no doubt one of the usual suspects will quibble and squall, but that won't make it false. It's why there was a flap about ceramic engines to work at high temps, back in the 1960s. then they discovered that NOx was a pollutant, and that anything over about 2300 deg or thereabouts made it in quantity.

    The peak temp in a gas engine as traditionally made, is quite high, higher than the usual diesel, so the Carnot efficiency can be higher. It generally is not, and there are plenty of details, but it could be.

    yes im familiar with Smokey Yunicks ceramic engines and such, iv just never heard anyone use that as the holy grail for judging that Gas is more efficient then Diesel, there's no reason you can't also create a diesel to run to extreme temps, i mean if you get to toss emissions out the window then so do I, I would think tie goes to the fuel with the greater BTU rating --? heat it up and burn it and see what you get...
    Last edited by A.K. Boomer; 06-16-2019, 11:29 AM.

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  • Willy
    replied
    [QUOTE]
    Originally posted by strokersix;1243212..................
    ............................

    I don't understand why we don't just build diesels. This blending of the two does not make sense to me.[/QUOTE
    It boils down to dollars and cents and the economic viability of using diesel as a fuel despite some of it's inherent advantages.
    Emissions compliance has added at least 10-15,000 dollars to the cost of large truck engines. Add to this system maintenance and increased operational costs due to the complexity of these very integrated systems.

    Particulate matter emissions reductions have exceeded 98% and NOX has been reduced at least 95% from pre-emission enhancement technology days but clean air comes at a cost. Gasoline being somewhat easier to clean up, either in-cylinder or by using after-treatment is becoming more of a viable option in areas where diesel used to be the first choice.

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  • ed_h
    replied
    My understanding is that modern gasoline is composed primarily of straight chain (alkane) compnents of length up to 10 or 12 or so.

    Ed

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  • strokersix
    replied
    Diesel fuel molecular structure has long straight carbon chains. This encourages autoignition quickly so the fuel starts to burn as soon as it is injected.

    Gasoline is the opposite. Highly branched molecular structure to DISCOURAGE autoignition so the fuel does not start to burn until spark ignited.

    Using diesel in a gas engine results in early autoignition and knocking. Using gasoline in a diesel engine results in lots of fuel injected before autoignition resulting again in knock. Very different combustion processes.

    I don't understand why we don't just build diesels. This blending of the two does not make sense to me.

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