Quote:
Originally Posted by teoman
So maybe beneficial for pulse and gliders.
|
Yes. The ideal gasoline engine, or even diesel engine for that matter, would have only one throttle position. Then you pulse and glide it. Or figure an efficient way to store and then apply it's pulsed energy. Some hydraulic pumps and motors and hydraulic accumulators are over 98% efficient.
But even then, just widening the intake or exhaust doesn't mean better efficiency. Everything in the intake and exhaust is pulsing with each intake and exhaust stroke. Harmonics become much more important here, which is affected greatly by runner diameters and lengths as well as resonate chamber designs. In other words, widening things can be just as bad as making them more narrow. And using the harmonics with finely tuned intakes and exhaust systems to get more air and fuel and exhaust in and out of the cylinders doesn't always equate to better fuel efficiency either.
I had stock exhaust and intake on my 1985 VW Golf diesel which the exhaust was less than 2 inches in diameter IIRC, and I got as much as 60mpg in it.