SNS COLLEGE OF ENGINEERING Coimbatore-107 Subject: Thermal Engineering Valve timing and port timing diagrams, PV diagrams-actual and theoretical BY Prabhakaran.T AP/MECH

Guess what??

VALVE TIMING In a piston engine, the valve timing is the precise timing of the opening and closing of the valves. In an internal combustion engine those are usually poppet valves and in a steam engine they are usually slide valves or piston valves.

4 stroke diesel

4 STROKE SI ENGINE

PORT TIMING DIAGRAM Since the one cycle is completed in one revolution of the crank, the sequence of operation of the ports can be represented in a circle (360°). This representation is known as a port timing diagram. The port timing diagram gives an idea about when a phase of the two-stroke cycle takes place.

PORT TIMING DIAGRAM

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Actual PV diagram SI Engine

Actual PV diagram CI Engine

Actual PV diagram of 2 stroke petrol engine

Actual PV diagram of 2 stroke diesel engine

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