a four stroke engine the type of motor found in most automobiles uses four strokes in power cycle intake compression power and exhaust during the intake stroke piston sucks in air and fuel mixture through intake valve the valve closes and the piston compressing the air and fuel to an explosive level the power stroke begins before the piston reach the top

a four stroke engine the type of motor found in most automobiles uses four strokes in power cycle intake compression power and exhaust during the intake stroke piston sucks in air and fuel mixture through intake valve the valve closes and the piston compressing the air and fuel to an explosive level the power stroke begins before the piston reach the top,and the spark plug burn the mixture,which forces the piston down,turning the crankshaft.In the exhaust stroke the exhaust valve opens the piston push out the burn gas until the top of stroke and exhaust valve closes the intake valve opens again.