I .FIRST.....THE FOUR STROKE

 

THE FOUR STROKE INTERNAL COMBUSTION CYCLE.  I

INTAKE STROKE. 

The crankshaft rotates. This makes the piston move downs the cylinder, away from the valves. At the same time, the cam above the intake valve rotates. This makes the valve move downwards, wich opens the intake port. As the piston moves down, fuel is sucked into the cylinder through this inlet.

COMPRESSION STROKE

. As the crankshaft rotates, it makes the piston move up the chamber towards the valves. Simultaneously. The cam above the intake valve rotates and allows it to close. Both valvves are now closed. As the piston moves up towards the valves, it compresses the fuel.

                                          POWER STROKE

Just before the piston reaches top dead center, the mixture is ignited by a spark plug. The third stroke, the power stroke harnesses the energy of the explosion by allowing the piston to be forced downward from top dead center. This linear motion is changed to rotational motion by the crankshaft.

EXHAUST STROKE

 The last stroke is the exhaust stroke. During this last upward movement of the piston the exhaust valve is open. The piston forces all of the burned gasses from the previous explosion out of the cylinder. The cycle is completed and can begin again.

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