Ethanol Improves Efficiency in Gasoline Engine?

[bonzoboy]

I realize there are a ton of comments on ethanol. But I ran across a story from a team in Philadelphia that claimed that injecting liquid ethanol into the gasoline engine (probably just before spark ignition occurs), resulted in 20-25% improvement in efficiency (in the engine--not sure if this was engine or dyno tested). I was a bit taken back by this, and I'm curious, can you just change the way the fuel is injected into the cylinder, and recover enough to compensate for the lower heating value in ethanol? It seems counter-intuitive to me, but I thought I'd run this by some experts.

 

[GregLocock]

Snake oil

There has been work on using hydrogen as a combustion efficiency improver, but the effects are fairly small, and occur for well understood reasons, which would not apply to ethanol, by and large.

After all, quite a few racing teams would be interested in a 20-25 % power boost, even if those of us who are paid to keep quiet by Big Oil weren't interested.

Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[btrueblood]

Certainly it works, if you use the right math: inject 25% by weight of ethanol more fuel into the engine (than is being delivered by the normal gasoline fuel injectors), and then just don't account for the ethanol in the efficiency calculation.

Similar calculations were used by Enron...

 

[DoradoX]

I don't recall where I read ( Car and Driver?)it but it sounds like the group that is using E85 as an anti knock agent. basically replace a 3.6L normally aspirated engine with a 1.8L turbo that also has a high compression ratio. During no boost operation fuel economy increases due to small engine /high compression then when power is needed boost + E85 to to prevent detonation. Cars would be required to carry both gasoline and E85 in separate tanks.

 

[crysta1c1ear]

Direct Injection Ethanol Boosted Gasoline Engines

 

[globi5]

crysta1c1ear,
Well if you look at it this way, one could argue that with a downsized, high boost engine, a similar result could be achieved with water injection (instead of ethanol).