The 100 mpg carb - Does it really exist?

[mpgmike]

Originally Posted by Pinhead

BTT...

Does anyone know what is wrong with lean burn with current technology?

Back in 2000 I had the opportunity to interview the top engineer at Seimens' Corp (the guys that replaced Bosch in making our modern OEM fuel delivery systems) named Peter Rice. I asked him questions along these lines:
Q) Do your systems shut off fuel on decel?
A) Oh absolutely not! Even though the engine doesn't need fuel to keep turning, if we shut the fuel off, the catalytic converter might cool down. When you hit the accelerator again, there'd be a brief moment of higher pollution.
Q) Back in the late '70s Chrysler had their Lean Burn 318 engines. These engines were horrid with their open chamber heads, lousy carbs, and poor manifolding. Surely if Chrysler could do it back then, modern engines could do better with a lean cruise mode.
A) Oh no! By leaning out the engine the catalytic converter might not operate at peak efficiency.....
Q) As far as improving fuel economy goes, have you ever.....
A) We couldn't do that...catalytic converter....

The Green Peace types have been dubbed "tree huggers". Maybe we should dub the OEMs the "cat huggers".

Mike

[Belgian1979vette]

David,

Thanks for the info. I have about four books here that you wrote on the SBC. When building my short stroke big bore SBC I followed your advice. Although the car is not yet completed it promises to be a very good engine. However I would like to read up on all the subjects that you touched in your topic.

[MadBill]

The trouble with lean burn in North America is NOx emissions. All current North American gasoline vehicles AFAIK, run at stoichiometry (actually, the mixture 'dithers' in a narrow band either side), which permits the catalytic converter to both oxidize CO and unburned hydrocarbons and reduce NOx. Running more than a few percent lean lean makes this impossible with conventional technology (although some strategies adopted to bring '08 diesels up to US/Canadian standards may be applicable) The same Direct Injection gasoline engines which use lean burn in Europe are calibrated to run at stoichiometry in NA.

[DavidVizard-GFN]

I wonder why OEM does not experiment more with water injection. sure it puts a little more responsibility on the end user but H2O injection eliminates NOX - now we can run lean burn!

[Belgian1979vette]

I thought waterinjection was only for turbo or high compression engines.

[Pinhead]

I wonder why the OEM's don't do a lot of things that they could be doing to increase efficiency. Such as hydrogen-enriching gasoline in lean-burn mode, fuel heat, etc...

[maxc]

"Steam" in my opinion, is one of the "key" ingredients that makes the PICC perform.
Smokey Yunick indirectly used it in he's anabolic engine. I think it's no longer posted on Smokey's web site that he used water injection.

Mark

[DavidVizard-GFN]

Belgian1979vette

Can I guess what you drive and how many guesses do I get???
Your point on H2O for high CR and blown motors is correct. Water does not of itself contribute toward fuel economy but high compression does and water allows low octane fuel to go really high without detonation (at college we ran a tractor engine on kerosene at 17/1 and a lot of water!).

Pinhead - too many times it's a play it safe deal - in the corporate world if you don't make mistakes your chances of promotion are better. Also the not invented here syndrome comes heavily into play - to my mind that trait is a sign of insecurity!

Marxc - I tried a steam injection kit from a UK manufacurer many moons ago. It more or less did what water injection did. Might talk more about that in a future article. As usuall Smokey was on the right track.

DV

[Pinhead]

Originally Posted by maxc

"Steam" in my opinion, is one of the "key" ingredients that makes the PICC perform.
Smokey Yunick indirectly used it in he's anabolic engine. I think it's no longer posted on Smokey's web site that he used water injection.

Mark

But if the PICC is tuned correctly, there should be very little steam getting into the engine. It's the hydrogen/oxygen that helps speed the burn and allows to run leaner mixtures.

[seattle smitty]

Since we are side-tracked from the original topic for the time being, here's my two cents:

Water injection eliminates NOX, but only while it is being injected. If you want to eliminate NOX full-time ANNNND take out the d@mned EGR system, you need full-time water injection. Happily, this can be done in a way that doesn't require a big water tank. (I've described this elsewhere, some time back, so for those who remember, forgive this redundancy).

DV, did you ever encounter an engine-builder named Pat Goodman? Maybe twenty years ago, while he had a shop in Virginia, he built a Ford Fiesta (Kent engine) with very high compression by street standards, and took a Popular Science writer (it wasn't Yunick) on a long run during which he was getting highway mpg figures well into the 50s. Goodman, who has aviation connections, and was a dealer for Franklin aircraft engines for a time, had found an aerospace injector that was cheap and which would atomize water at very small flow-rates. The secret was a second port that admitted low-pressure air which was injected at the water outlet, breaking it up into a mist. As a pressure source, Goodman tapped into the 4psi air from the "smog-pump." He mounted the injector in the air-cleaner top, above the carburetor primary side. Awfully simple, but it worked! It ran all the time, but used little water. Popular Science did a good article on it, which I will try to locate. Even Mother Earth News, which has approvingly offered up some of the crudest, most cobbled-together amateur plans for homemade water injections, helped get the word out about Goodman's system. But it disappeared, as the American public lost interest in fuel economy for another couple of decades . . . .

By the way, does anyone else find the EGR system inherantly offensive? I have learned to accept, and even appreciate, most of the emissions systems on street cars, but for an old racer the very idea of PURPOSELY adulterating the fresh intake charge with exhaust gases really rubs me the wrong way!! (I probably have said this somewhere else, too. Old men repeat themselves because we figure nobody pays any attention to what we say . . . which is probably merited!!)