increase efficiency

increase power

reduce weight and bulk for a given out-put

effect fuel economy

scavenging

turbulence

supercharging

pre-ignition

diesel engines

gas turbines

petrol engines

aircraft engines

half the operating speed

one-fourth of operating speed

250-300 rpm

60-80 rpm

exhaust valve opens at 35° before bot-tom dead center and closes at 20° after top dead center

exhaust valve opens at bottom ′dead center and closes at top dead center

exhaust valve opens just after bottom dead center and closes just before top dead center

may open and close anywhere