AdministratorHow do you read a 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 happens if exhaust valve opens late?
If the exhaust valve closes too late in the cycle, the combustion chamber will be “over-scavenged”. This will cause an excessive amount of fuel/air mixture to escape into the exhaust port because the intake valve is still partially open.
Why does inlet valve open before TDC?
If the inlet valve closes at this point, the cylinder will receive less charge than its requirement. Hence, the inlet valve is kept open until the piston enters its next upward stroke i.e the compression stroke. At this point, the pressure in the cylinder becomes almost equal to the atmospheric pressure.
Why is valve timing diagram needed?
The valve timing diagram is modified to set better charging and exhausting performance as there is always a difference between theory and practice. The valve timing diagram is drawn for two complete revolutions of the crankshaft means for one complete cycle.
How many times does the exhaust valve open in a cycle?
During one cycle, the piston makes two round trips and the crankshaft revolves twice. The inlet and exhaust valves open and close only once.
When should the exhaust valve open?
On the power stroke, the combustion pushes the piston down in the cylinder. During this stroke, it is necessary to open the exhaust valve before the piston gets to the bottom of the cylinder. This will allow the excess pressure in the cylinder to “vent out” just before the piston reaches the bottom of the stroke.
What is a valve timing diagram in a 4 stroke engine?
As we all know in 4-stroke engine the cycle completes in 4-strokes that are suction, compression, expansion and exhaust , The relation between the valves (inlet and outlet) and piston movement from TDC to BDC is represented by the graph known as valve timing diagram.
What is the cycle of operation of 2 stroke engine?
The closing and the opening of the ports will be operated by the movement of the piston itself. The cycle of operation of a 2 Stroke Engine consists of the following strokes: Exhaust stroke. 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.
What is the difference between two stroke engine and valves?
Two Stroke Engine uses ports rather than the valves. Port: Fluid can be operated inward and outward. Valve: The fluid can be operated in one direction only.
What are the factors that affect the valve timing?
There are two factors, one mechanical and other dynamics, for the actual valve timing to be different from the theoretical valve timing. (a) Mechanical factor. The poppet valves of the reciprocating engines are opened and closed by cam mechanisms.