The power output is now controlled by the amount of
fuel that is injected (as opposed to the amount of fuel-air
mixture for a gasoline engine), which is termed
Bqualitative control.[ Thus, part-load efficiency is much
better than for a gasoline engine as reducing the power
output does not rely on increasing the intake flow
resistance with a throttle valve. Peak efficiency is also
higher, because of the higher compression ratio of diesel
engines (in this case actually needed to obtain sufficiently