Four stroke engine

Definition of Four-stroke engine

    *Rudolf christian karl diesel(18/03/1858-29/09/1913) was a german inventor and mechanical engineer, famous for the invention of the four-stroke diesel engine.

    *Four-stroke ,engine was first demonstrate by nikolaus otto in 1876,hence it is also known as otto cycle.

Nikolause otto

                                  otto cycle

            *It consist of four -stroke one cycle operation is completed in Four-stroke of the piston that is one cycle is completed in every Two revolutions of the crankshaft.     

Four stroke engine

     *In a four stroke engine piston moves two times up and down in side the cylinder and complete Two crankshaft revolution during single time of fuel burn.

Working of four stroke Diesel engines

     *Following ate the four strokes;

         #Intake/suction stroke

           # Compression stroke

           # Expantion stroke

            #Exhaust stroke

The piston of an engine travels within Two limits mainly,

           1.Top dead center

           2.Bottom dead center

*A one travel within these two limits is called as stroke.

A Four-stroke cycle is a cycle in which the piston completes four separate strokes which constitute a single Thermodynamic cycle.

1.Suction stroke

*piston travel from TDC to BDC.

*Inlet valve is open.

*Exhaust valve closed.

*suction pressure in the combustion chamber decreased.

*Air fuel mixture drawn through the intake valve to the combustion chamber. 

2.Compression  stroke

*Piston travel TDC toBDC.

*Both intake and exhaust valves closed.

*Air fuel mixture compressed in the combustion chamber.

*At the end of the compression stroke fuel is ignited.

3.Power stroke

*Piston pushes down from TDC to BDC due to expantion of gases.

*Both inlet and exhaust valves are closed.

*Useful power done by the piston

4.Exhaust stroke

*Piston travel from BDC to TDC.

*Exhaust valve is open.

*Inlet valve is closed.

*Burnt exhaust gasses passes through exhaust valve.