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Unformatted text preview: he inlet valve is less as compared to exhaust valve. Thus,
the inlet valve is generally made of nickel chromium alloy
piston and crankshaft
steel and the exhaust valve (which is subjected to very high
temperature of exhaust gases) is made from silchrome steel
which is a special alloy of silicon and chromium.
In designing a valve, it is required to determine the following dimensions:
(a) Size of the valve port
Let ap = Area of the port,
vp = Mean velocity of gas flowing through the port,
a = Area of the piston, and
v = Mean velocity of the piston. We know that
∴ ap.vp = a.v
vp Internal Combustion Engine Parts Fig. 32.21. Poppet or mushroom valve. n 1191 Fig. 32.22. Conical poppet valve in the port. The mean velocity of the gas (vp) may be taken from the following table.
Table 32.3. Mean velocity of the gas (vp )
Type of engine Mean velocity of the gas (vp ) m/s
Inlet valve Exhaust valve Low speed 33 – 40 40 – 50 High speed 80 – 90 90 – 100 Sometimes, inlet port is made 20 to 40 pr...
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This note was uploaded on 09/30/2012 for the course MECHANICAL 403 taught by Professor A.thirumoorthy during the Spring '11 term at Anna University Chennai - Regional Office, Coimbatore.
- Spring '11