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Lazarus 01-01-2008 11:31 AM

Direct Injection Ethanol Boosting + Turbocharging
This is over a year old. Has anyone heard if they done anything with it? It's a very interesting idea and straight foward.


The foundation of the approach is the enhanced knock suppression resulting from the separate, direct injection of small amounts of ethanol into the cylinder in addition to the main gasoline fuel charge.

Efforts to improve the efficiency of the conventional spark-ignition (SI) gasoline engine have been stymied by a barrier known as the knock limit. Changes that would have made the engine far more efficient would have caused knock (spontaneous combustion).

The injection of a small amount of ethanol into the hot combustion chamber cools the fuel charge and makes spontaneous combustion much less likely. According to a simulation developed by the MIT group, with ethanol injection the engine won’t knock even when the pressure inside the cylinder is three times higher than that in a conventional SI engine. Engine tests by collaborators at Ford Motor Company produced results consistent with the model’s predictions.

With knock essentially eliminated, the researchers could incorporate into their engine two operating techniques that help make today’s diesel engines so efficient: a high degree of turbocharging and the use of a higher compression ratio.


The result is a gasoline engine with the fuel efficiency of current hybrids or turbodiesels—up to 30% better than a conventional gasoline engine—but at lower cost.

DAN 02-04-2008 04:21 AM

not me. its a old hot rod idea to. and has and is being done. dyi with big bucks for power only. take a trip to book store and look in the car part, under power. but stock car motors will not take high bost. not and hold up. vw has a tdi(?) motor that is a smaller motor with a supercharger boosted with a turbocharger. the only way of improving the ic motor is using the waste heat. and that's what turbochargers do. but car makers have not had big sales of them. its better for them to make a bigger motor. then, maybe not now.

DAN 02-04-2008 04:30 AM

real water injection will save the motor without Ethanol. Ethanol or water injection is not epa approved. the motors must past 1000,000 miles without a aiding water or Ethanol out side of ordinary fuel.

tasdrouille 02-04-2008 02:26 PM

Well...for diesels there is propane injection too, which acts mostly as a catalyst in the combustion process. You can safely add 20% power to an otherwise stock engine. Hence the potential to reduce engine size to acheive the same power output. From my understanding of gassers, propane is the diesel equivalent of hydrogen injection, the difference being that in diesels we don't try to generate the gas on the fly...we use an external tank.

There is no doubt that there are alternatives that have potential to increase FE, but sometimes they are not practical or safe enough to be used in OEM applications.

MetroMPG 02-05-2008 09:34 AM

Interesing article.

If in fact it's true as DAN says that the EPA won't permit a second tank needed to improve efficiency or reduce emissions, how are they handling the urea tank that VW and MB are using in their cleaner diesel vehicles?

I could see something like this ethanol injection taking hold, because the vehicle owners have a self-serving incentive to keep the secondary tank full: more power and higher efficiency. The car's computer would simply dial back the power and increase fuel consumption should the ethanol run out.

This is unlike the owners of urea injected diesels, whose only incentive for keeping their urea tank full is "to help keep the air clean". (Hmmm, maybe the EPA needs to decree that urea-equipped diesel computers must dial back power if the urea runs out :))

roflwaffle 02-05-2008 01:20 PM

Actually, I think in Europe and over here, if the urea tank runs out, the ECU throws a CEL. This could be why CA is moving towards smogging diesels.

Snorg 01-24-2009 09:21 AM

Old cars had lots higher compression, govt made them lower it as part of pollution control and to make them run on 85 octane. The even made them lower the compression on lawn mowers.

aerohead 01-24-2009 04:27 PM

There's no question that it works.Uncle Sam used to pay me to mix up a cauldrons brew of demineralized H2O and methanol alcohol for injection into Douglas A-1 E Skyraiders,so the engines wouldn't meltdown on takeoff.------------------ I do believe there are other issues with regards to higher compression-ratios,and trade-offs with emissions.That's kinda a can o' worms.------------- With modern knock-sensor technology I believe automakers are able to achieve fairly high ratios with the electronics protecting the guts of the engine by limiting spark advance to head off detonation.So maybe the alcohol injection isn't as important an issue today as in past times.Since engine-makers are working on variable-compression-ratio technology,that may remain a big issue.

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