Quote:
Originally Posted by Allch Chcar
It's valid because I say so. lol
Actually it is a pure factor, Displacement is a direct indicator of fuel economy as it is of Torque. You can adjust gearing, cam, and vehicle size. But the displacement determines a large amount of the fuel consumption for cruise and acceleration. Otto cycle ICE is more efficient at greater loads.
Honda has two engines on their Japanese Fit(best example I have) the 1.5liter and the 1.34liter. The 1.34 has been proven to be 20% more fuel efficient in the same car with the same gearbox (CVT 73% efficient).They are not 20% apart in displacement.
Compression ratio also affects torque and fuel economy. DI increases all three.
2liter vs 1liter is a very large difference. What about 2.0liter to a 2.5liter or a 1.8liter to a 1.6liter or even a 2.0liter?
|
No. (I'm in an argumentative mood today. Not always this much of a ****...)
Air mass and desired mixture ratio determine the engine's output. This is not the same thing as just the size of the motor. Engine is an air-pump analogy, blah... blah...
DI allows the engine to be tuned to run well in a leaner state which can be used to increase output OR reduce fuel requirements for the same output.
It doesn't increase compression ratio. It allows engines to be run with higher compression ratios safely.
I don't quite follow the Otto cycle is more efficient at greater loads statement. Could you expand on this? Because I don't see how this relates to a vehicle's fuel consumption. ie: just because an engine is running at it's most efficient range, does not mean it is using the least amount of fuel.