air fuel ratio

air temperature

air flow speed

exhaust gas volume

mixes fuel with air

promotes combustion by creating a swirling movement in the air fuel mixture

returns blow by gases from the crank case to the intake system

feeds blow by gases to the exhaust manifold

improved fuel efficiency

improved emission

improved power output

all of these

clutch

differential

flywheel

torque converter

supercharging

auto ignition

scavenging

detonation