There are engine technologies immediately available that could easily double fuel mileage in any vehicle to which it was applied....the EPA gets into the fray with its NOx emission maxima that knocks the whole scheme into a cocked-hat.

Ford had such a scheme applied to a big V8 diesel: Ceramic insulated combustion chambers. The insulation was so efficient that no water jacket was necessary; oil and intake air were sufficient for all the necessary cooling. The engine ran at 70% efficiency. The best current diesel is about 41% efficienct and the best gasoline engine about 30%, so you can see the improvement. The EPA killed the scheme because the NOx emissions were too high based upon very high combustion temperatures largely responsible for the high conversion efficiency.

I saw the article about three years ago and I have been searching anew for it, but it appears to have been removed from the archives.

 

Forget heavy 4-strokes. Direct inject a 2-Stroke is twice the fire and twice the power is you ever see a jet ski light switch away from a 4-stroke is haul the whale? I mean, mail.

 

Good point, and the Evinrude E-tech series of outboards is proof enough.

GM had the two-stroke series of diesels, 53 and 71, that were fairly efficient, BSFC of 0.4, and more powerful by about 40% than a 4-stroke of equivalent displacement, but the EPA killed them because the cylinder scavaging arrangement allowed a little crankcase lube oil to enter the combustion chamber.

 

There is no dumb questions if you truly don't know the answer to them, just because everybody else knows doesn't mean you should.
Ask away