Four stroke.

Ever wondered that what is men't by four stroke engine? Well i'll tell you. Four stroke is basically the working of the pistons in petrol and diesel engine. I will explain it with petrol engine.

1- Intake stroke.
2- Compression stroke.
3- Power stroke.
4- Exhaust stroke.

* Intake Stroke:
           The cycle starts in intake stroke in which the piston moves outward and petrol air mixture is drawn through an inlet valve into the cylinder from the carburetor.

* Compression Stroke:
               On the compression stroke,the inlet valve is closed and the mixture of air and petrol is compressed by the inward movement of the piston.

* Power Stroke:
                 An electric spark is produced by the sparking plug. On the power stroke a spark fires the mixture causing rapid increase in pressure and temperature. The burning mixture expands and forces the piston to move outwards. This is the only working stroke in the cycle which delivers power to the crankshaft to drive the flywheel.

* Exhaust Stroke:
                  In the exhaust stroke, the outlet valve opens. The residual gases are expelled and the piston moves outward. The cycle then begin again.