4 Stroke Petrol Engine

Engine displacement

The 4 Stroke engine cycle consist of these: 1) Intake 180degree2) Compression 180

degree3) Power/ Combustion 180

degree4) Exhaust 180

degree

Total engine revolution 720 degree

4 Stroke Cycle

The Intake Stroke consist of the piston

travelling down.

Intake valves are open to allow

Air/Fuel mixture to come into the combustion chamber.

Intake

It is an electrical device that fits into the cylinder head and ignites air fuel

mixtures.

Spark plugs

Inlet valve open

Piston downINTAKE STROKE

Exhaust valve closed

Inlet valve open

Piston downINTAKE STROKE

Fuel in

Exhaust valve closed

Compression stroke consist of the piston travelling back up.

Both intake and exhaust valves are closed

Air fuel mixture is now being compressed

Compression

Inlet valve closed

COMPRESSION STROKEPiston up

Exhaust valve closed

Inlet valve closed

COMPRESSION STROKE

Piston up

Exhaust valve closed

The piston is now at the TDC

Spark plug ignites, creating a spark that ignites the compressed air fuel mixture.

Explosion is created and the piston is forced back down.

Hence the Power stroke

Both valves are still closed

Combustion/Power

Inlet valve closed

POWER STROKE

Exhaust valve closed

Inlet valve closed

POWER STROKEPiston downpowerfully

Exhaust valve closed

Exhaust stroke the piston is travelling

up

Exhaust valve is open

Intake valve is Closed

Exhaust gases being pushed out by piston

Exhaust

Inlet valve closed

EXHAUST STROKE

Exhaust valve open

Piston up

Exhaust gasesout

Inlet valve open

INTAKE STROKE

Exhaust valve closed

Basic Components of Four-Stroke Engines

Intake Valve

Valve Cover

Intake Port

Head

Coolant

Engine Block

Oil Pan

Oil Sump

Crankshaft

Camshaft

Exhaust Valve

Spark Plug

Exhaust Port

Piston

Connecting Rod

Rod Bearings