Questions set 75

Transmission System – Gear Box

1.      Which of the following is the need of the gearbox?
a) To vary the speed of the vehicle
b) To vary the torque of the vehicle
c) To vary the power of the vehicle
d) To vary the acceleration of the vehicle
Answer: b
Explanation: The purpose of the gearbox is to give means so that the torque can be varied as required between the engine and the road wheels.

2.      In which type of manual transmission the double-declutching is used?
a) Constant-mesh gearbox
b) Sliding mesh gearbox
c) Synchromesh gearbox
d) Epicyclical gearbox
Answer: a
Explanation: The double-declutching is used in the constant-mesh gearbox. For the smooth engagement of the dog clutch, the speed of the main shaft and layshaft should be the same.

3.      In which of the gearbox all gears are always in contact?
a) Constant-mesh gearbox
b) Sliding mesh gearbox
c) Synchromesh gearbox
d) Epicyclical gearbox
Answer: a
Explanation: In constant mesh gearbox, all gears on the layshaft and main shaft are in contact all the time. For selecting gear, the dog clutch is used.

4.      . In which of the gearbox sun and planet gear set is used?
a) Constant-mesh gearbox
b) Sliding mesh gearbox
c) Synchromesh gearbox
d) Epicyclical gearbox
Answer: d
Explanation: In epicyclic gearbox, the sun and planet gears are used. Using this arrangement various gear ratios can be obtained. Also, this type of gearbox is compact in design than other types of gearbox.

5.      Where is the overdrive located?
a) Between transmission and engine
b) Between transmission and rear axle
c) Between transmission and propeller shaft
d) Between transmission and differential
Answer: c
Explanation: The overdrive is used to increase the gear ratio of the vehicle. It used where the high speed is needed at relatively low engine speed. By using overdrive, the wear of the engine parts is less and decreases the vibration and noise.

6.      Which of the following is not part of automatic transmission?
a) Epicyclic gearbox
b) Torque convertor
c) Multi-plate clutch
d) Sliding mesh gearbox
Answer: d
Explanation: The automatic transmission consists of the epicyclic gearbox, torque convertor, and multi-plate clutch. The sliding mesh gearbox is a type of manual transmission.

7.      In which of the configuration of epicyclic gearbox output will be forward and fast output speed?
a) Sun gear stationary, ring gear driven, planet carrier driving
b) Sun gear driving, ring gear driven, planet carrier stationary
c) Sun gear driven, ring gear stationary, planet carrier driving
d) Sun gear stationary, ring gear stationary, planet carrier driving
Answer: a
Explanation: When the Sun gear is stationary, the planet carrier is driving and the ring gear is driven then output is forward and fast speed. When any two of the three are stationary then we get the direct drive.

8.      Which types of gears are used in constant mesh gearbox?
a) Spur gear
b) Helical gear
c) Bevel gear
d) Worm gear
Answer: b
Explanation: As the gears are always in mesh in the constant-mesh gearbox, therefore there is no need for using the spur gears and the helical gears are used as those are quite in use.

9.      Why are the helical gears used commonly in transmission over spur gears?
a) Low cost and high strength
b) Low noise level and high strength
c) Low noise level and economy
d) Low noise level and low cost
Answer: b
Explanation: The teeth profile on the helical gear is at an angle to the axis of the gear because of which helical gears produce less noise during operation and also they have high strength.

10.  Increase of torque in a vehicle is obtained by decreasing power.
a) True
b) False
Answer: b
Explanation: Increase of torque in a vehicle is obtained by decreasing speed. As we know P = 2πNT/60 for the same power (P), T (torque) is inversely proportional to N (speed).