What is Port timing diagram of 2 stroke engine?

The port timing diagram gives an idea about when a phase of the two-stroke cycle takes place. When the piston move from BDC to TDC – Transfer port close, Exhaust port close, Inlet port open. When the piston moves from TDC to BDC – Inlet port close, Exhaust port open, Transfer port open.

What is significance of valve timing diagram?

A valve timing diagram is a graphical representation of the opening and closing of the intake and exhaust valve of the engine, The opening and closing of the valves of the engine depend upon the movement of piston from TDC to BDC, This relation between piston and valves is controlled by setting a graphical …

What is the effect of valve timing on engine performance?

Shorter valve opening durations improved torque at lower engine speeds. The longer the valve opening duration, the lower was the air trapping efficiency. Higher exhaust backpressure and lower valve lift reduced the compressor work.

What is valve timing?

Valve timing is the exact timing of the opening and closing of the valves in a piston engine. Carmakers have devised ways to change valve timing while the engine is running.

What is Port timing?

The above processes will be operated with the sequence of operations of ports in the 2 stroke engine. This can be represented on a circle. This is called the Port Timing Diagram. This Port Timing diagram will illustrate how the events such as the Inlet port, Exhaust port and Transfer ports are open and closes.

What is the angle at which the ignition starts in practical valve timing diagram of SI engines?

(c) The ignition (IGN) of charge takes place at 20°— 30° before TDC. (d) The expansion starts at 20° — 30° before TDC and ends at 30° — 50° before BDC. (e) The exhaust valve opens (EVO) at 30° — 50° before BDC and closes at 10° —15° after TDC.

How does valve timing affect volumetric efficiency?

At higher engine speeds, retarding the IVC time increases the volumetric efficiency. Volumetric efficiency was increased by 4.8% at 3000 rpm when the IVC time was retarded 20 ºCA. However at a low engine speed of 2000 rpm the volumetric efficiency was decreased by 4.7%.

What are major two factors which affect valve timing?

It can be varied by modifying the camshaft, or it can be varied during engine operation by variable valve timing. It is also affected by the adjustment of the valve mechanism, and particularly by the tappet clearance.

What are the types of valve timing?

Continuous cam-phasing variable valve timing. 2-stage variable valve lift plus valve-opening duration.