[John Jamieson]

Carnot efficiency goes up with extended power stroke ratio. (i've been calling it exhaust stroke) that's the point. we're looking for 50% not 100%.

[mamelukesabre]

Carnot efficiency goes up with extended power stroke ratio. (i've been calling it exhaust stroke) that's the point. we're looking for 50% not 100%.

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Let me see if I grasp the concept here. If you design an engine with a LONG stroke to run at SLOWER speed, you accomplish the same thing, correct? Isn't that why GM can get their new chevy impala to run at the same fuel efficiency as the honda accord? Even though the impala has nearly twice the engine displacement and approx 30% more horspower and the vehicle weighs at least 500 pounds more? Let those foreigners keep their little multi-cammed "motorcycle" engines. You guys ever checke the MPG ratings on one of those new bikes they call rice-rockets? It's really pathetic.

It seems to me that the guy that suggested keeping the valves open for a little while while the compression stroke started has the right idea. Just combine that concept with what Chevy is already doing and you got a real idea. Or is that what they are already doing with the miller cycle?