This set of Automobile Engineering Multiple Choice Questions & Answers focuses on “Engine Valves and their Mechanisms”.
1. In a four stroke engine each cylinder has
a) One valve
b) Two valves
c) Three valves
d) Four valves
View Answer
Explanation: A four stroke engine cylinder has one intake and one exhaust valve.
2. In a diesel engine the fuel injection pressure is in the range
a) 100 to 170 atm
b) 60 to 70 atm
c) 30 to 40 atm
d) 20 to 25 atm
View Answer
Explanation: The pressure of fuel injection is very high for a diesel engine.
3. The valve is opened as the cam lobe on the cam raises the
a) Bearing
b) Piston
c) Valve lifter
d) Valve seat
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Explanation: Valve opens when valve lifter is raised.
4. Exhaust valve temperature is about
a) 35 degree celsius
b) 100 degree celsius
c) 150 degree celsius
d) 500 degree celsius
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Explanation: The temperature of the exhaust valve is of the order of 500 degree celsius.
5. The size of the engine intake valve is
a) Same as that of exhaust valve
b) Smaller than that of exhaust valve
c) Larger than that of exhaust valve
d) Does not depend upon the size of exhaust valve
View Answer
Explanation: In most ICE engines, the intake valve is typically larger in size compared to the exhaust valve. This allows for more efficient intake of air-fuel mixture into the combustion chamber during the intake stroke, helping to optimize engine performance.
6. The device used to measure the clearance between the valve and tappet of an IC Engine is
a) Feeler gauge
b) Snap gauge
c) Slip gauge
d) Micrometer
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Explanation: A Feeler gauge is used to measure the clearance.
7. The purpose of valve clearance is to
a) Allow the valve to expand
b) Allow the sliding of valve in the guide
c) Ensure that the valve closes fully
d) Ensure that the crankshaft is free to rotate
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Explanation: Valve clearance ensures that valve closes completely.
8. The opening and closing of a valve is respectively done by
a) A cam and a spring
b) A spring and a cam
c) Gas pressure and cam
d) Cylinder vacuum and spring
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Explanation: An engine valve is opened by a cam and closed by a spring.
9. On modern four stroke engines the exhaust valve opens just
a) Before TDC
b) After TDC
c) Before BDC
d) After BDC
View Answer
Explanation: Exhaust valve opens before the piston reaches Bottom Dead Centre.
10. On modern four stroke engines the inlet valve opens just
a) Before TDC
b) After TDC
c) Before BDC
d) After BDC
View Answer
Explanation: Inlet valve opens before the piston reaches Top Dead Centre.
11. A relief valve is fitted to the main oil gallery of an engine. The purpose of this valve is to
a) Limit the maximum oil pressure
b) Open when the oil is hot
c) Maintain the supply if the gallery becomes blocked
d) Stop the oil flow to the bearings
View Answer
Explanation: A relief valve limits the maximum oil pressure.
Sanfoundry Global Education & Learning Series – Automobile Engineering.
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