Don't be fooled about "engine speed" by only looking at crankshaft rpms:
Most powerful diesel in the world: 98" stroke at
102 rpm = 1,666 ft/mn piston speed
Honda 50cc Super Cub at max fuel efficiency speed: 1.63" stroke at
4300 rpm = 1,168 ft/mn piston speed.
Hmmmm.
Yes one is a supercharged two-stroke diesel and one is a four stroke gasser. Different engine types seem to have different piston speed ranges for max fuel efficiency.
Quote:
|
I believe the trick for a gasoline engine is to have the manifold vacuum to be as minimal as possible, and the engine displacement times the RPM to be as small as possible.
|
You can easily drop off the bottom end of the engine's efficiency zone by doing that.