how a four stroke engine works..

How Does A Four Stroke Engine Work???

A four stroke engine works through creating power through the four stroke cycle inside the engine cylinders. Engine cylinders (bore) is where the four stroke cycle takes place in. Cylinder's are in the blocks. The hole in the cylinder is called the bore. In order to find out how a four stroke engine works you first need to know what the four strokes are and when they take place and how they take place and what the result of each stroke is. A stroke is one complete down or one complete up movement of the piston, (piston movement from T.D.C to B.D.C)The four stroke's in the four stroke cycle are intake, compression, power, exhaust.

In the Intake Stroke air fuel mixture is suked in through the intake port (valve) which is on top of the cylinder in to to the chamber (cylinder) when the piston is moving down. The exhaust port is closed. The ports (valves) are opened and closed through the lifter resting on camshaft. As the cam turns the lifters get lifted and put back down. The cam is turned by it being connected to the crank by the cam belt. And as the cam shaft gear is bigger it turns at half the speed of the crank.

Once the piston reaches B.D.C the top half of the cylinder is filled with the as much air-fuel mixture it can take which is ready to be compressed. Only the top half gets filled as the piston rings prevent air-fuel mixture going to the bottom through the edges of piston. At this point the inlet valve gets closed up.this is the end of the INTAKE stroke.

Now the piston starts to travel upwards to T.D.C which starts the COMPRESSION stroke. As the piston rises up it compresses the air fuel, at this point both intake and exhaust ports are closed.

Just before T.D.C spark plug ignites air-fuel mixture through ignition system sending a high voltage to spark plug. BANG. Because of air-fuel mixture igniting their is a release of heat and because of pressure send's the piston back down. This is the POWER stroke.

Once the piston reaches B.D.C again the EXHAUST valve opens up releasing pressure inside the cylinder. Piston starts to move up and pushes burnt gases out through the exhaust port through to the exhaust system. This is the EXHAUST stroke.

Once the piston reaches T.D.C the exhaust port closes and inlet valve opens up, and we come back to the INTAKE stroke.

The first practical four stroke piston cycle internal combustion engine was created by a man named Nicolaus Otto in May 1876.

Refrences: http://inventors.about.com/library/inventors/blotto.htm
www.youtube.com/watch?v=_y6PS-2j2U9