# Automotive Engine Auxiliary Systems Questions and Answers – Valve Train Component Details

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This set of Automotive Engine Auxiliary Systems Questions and Answers for Campus interviews focuses on “Valve Train Component Details”.

1. What is that part of a cam lobe which controls the valve opening called as?
a) Coldspot
b) Hot spot
c) Low spot
d) High spot

Explanation: A camshaft is a shaft with a cam for each intake and exhaust valve. Each cam has a high spot called cam lobe which controls the valve opening.

2. In which type of engine Valve train is not present?
a) 4-stroke petrol engine
b) 2-stroke petrol engine
c) 4-stroke diesel engine
d) Boxer engine

Explanation: Valve train is not present in the 2-stroke petrol engine, but to do the same work valves are replaced by ports, and its opening and closing is done by piston itself.

3. How many cam lobes are present on the camshaft per cylinder?
a) 6
b) 5
c) 3
d) 2

Explanation: There will be two cam lobes per cylinder head, one is for intake valve and another is for exhaust valve. In modern engines, Dual overhead cams are also present.

4. Why is the clearance given between bearing journals and the bores?
a) lubrication and metal expansion
b) Friction
c) For lubrication
d) Thermal expansion

Explanation: The clearance given between bearing journals and the bores are given for lubrication and metal expansion in the range of 0.05 to 0.125mm.

5. What is the range of clearance given between bearing journals and the bores?
a) 0.06 to 0.5cm
b) 0.025 to 1.2mm
c) 0.5 to 1cm
d) 0.05 to 0.125mm

Explanation:The clearance given between bearing journals and the bores are given in the range of 0.05 to 0.125mm. This also helps in cooling and reduces the wear due to friction.
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6. The end wise movement of the camshaft is limited by which component?
a) Key
b) Spigot
c) Thrust plate
d) Shear plate

Explanation:The end wise movement of the camshaft is limited by the thrust plate. Shear plate is added to bear the load in the weak joint of the welding.

7. What is the speed of the camshaft rotation?
a) Half the crankshaft speed
b) Double the crankshaft speed
c) Thrice the crankshaft speed
d) Same as crankshaft speed

Explanation: The speed of the camshaft rotation is half the crankshaft speed and in overhead cams,Chain or belt type of drive is used to drive the camshaft.

8. In overhead cams, which type of drive is used to drive camshaft?
a) Gear
b) Chain or belt
c) Chain
d) Toothed belt

Explanation: Chain or belt type of drive is used to drive the camshaft. Gears are space consuming and adds weight to the engine and also is requires lubrication. So, gears are not used.

9. Which component, transmit the torque load from the drive to the drive pulley?
a) Facing
b) Backing plate
c) Molded teeth

Explanation: Load-carrying cords are used to transmit the torque load from the drive to the drive pulley. These are made of very strong flexible glass-fiber cords.

10. What are bonded to the inside layer of the load-carrying cords?
a) Facing
b) Backing plate
c) Molded teeth

Explanation: Moulded teeth, which provide grip. Neoprene rubber teeth moldings are bonded to the inside layer of the load-carrying cords. Silent drive is the advantage of the toothed belt drive.

11. Which of the mentioned is the advantage of the toothed belt drive?
a) Silent drive
b) High vibration
c) High heat built up
d) High lubrication

Explanation: In a flat belt type, the stress distribution is uneven and there is a slip. To overcome this V-tooths are made on it. Silent drive is the advantage of the toothed belt drive.

12. Which material is not used for timing gear?
a) Cast iron
b) Steel
c) Nichrome
d) Aluminum

Explanation: Cast iron, steel, and aluminum are all the material used in timing gear based on their life. Whereas nichrome is a material that is usually found on the heating element.

13. Increased volumetric efficiency and reduced pumping losses can be done by varying cam timing using which component?
a) Variable cam phaser
b) Variable valve timing
c) Hard cam
d) Cylinder varying