McqMate
Chapters
1. |
Mechanical efficiency is the ratio of |
A. | brake power to heat input |
B. | indicated power to heat input |
C. | brake power to indicated power |
D. | friction loss to heat input |
Answer» C. brake power to indicated power |
2. |
Most commonly used lubrication system in automobiles is the |
A. | splash system |
B. | pressure system |
C. | petrol system |
D. | gravity system |
Answer» B. pressure system |
3. |
Friction that occurs between the layers of oil film is called |
A. | viscous friction |
B. | greasy friction |
C. | dry friction |
D. | boundary friction |
Answer» A. viscous friction |
4. |
Crankcase ventilation, is provided |
A. | to cool cylinder |
B. | to cool crankcase |
C. | to cool piston |
D. | to remove blow by |
Answer» D. to remove blow by |
5. |
the most important property of the lubricant is |
A. | density |
B. | viscosity |
C. | thermal conductivity |
D. | none of the above |
Answer» B. viscosity |
6. |
The maximum pressure in the lubrication system is controlled by |
A. | oil pump |
B. | oil filter |
C. | valve relief |
D. | supply voltage |
Answer» C. valve relief |
7. |
The lubricants commonly used in the automobiles are |
A. | animal oils |
B. | vegetable oils |
C. | mineral oils |
D. | cooking oils |
Answer» B. vegetable oils |
8. |
Detergents are oil additives used to |
A. | reduce viscosity |
B. | increase fire point |
C. | prevent sludge formation |
D. | prevent foaming |
Answer» C. prevent sludge formation |
9. |
Oil pressure in the dry sump lubrication system is around |
A. | 5 bar - 10 bar |
B. | 11 bar 15 bar |
C. | 3 bar - 8 bar |
D. | 1 bar |
Answer» C. 3 bar - 8 bar |
10. |
For mep decreases when using |
A. | single cylinder engine |
B. | smaller number of larger cylinders |
C. | larger number of smaller cylinders |
D. | none of the above |
Answer» C. larger number of smaller cylinders |
11. |
With increase in compression ratio, mechanical efficiency |
A. | increases |
B. | decreases |
C. | remains constant |
D. | compression ratio has nothing to do with ƞmech |
Answer» A. increases |
12. |
Blow by losses are |
A. | directly proportional to the inlet pressure |
B. | inversely proportional to the inlet pressure |
C. | proportional to the square root of inlet pressure |
D. | none of the above |
Answer» C. proportional to the square root of inlet pressure |
13. |
Mist lubrication system is mainly used in |
A. | four-stroke petrol engine |
B. | four-stroke diesel engine |
C. | two-stroke petrol engine |
D. | Wankle engine |
Answer» C. two-stroke petrol engine |
14. |
Additives are added in lubricant to have |
A. | detergent-dispersant characteristics |
B. | pour point depression |
C. | antifoam characteristics |
D. | all of the above |
Answer» D. all of the above |
15. |
The principal surfaces requiring lubrication in an IC engine are |
A. | cylinder head |
B. | crankcase |
C. | inlet and exhaust manifold |
D. | none of the above |
Answer» D. none of the above |
16. |
The heat given to cooling medium in IC engines is about |
A. | 50-60% |
B. | 30-40% |
C. | 10-20% |
D. | 60-70% |
Answer» B. 30-40% |
17. |
Radiator is provided to |
A. | cool the jacket water |
B. | pressurise the cooling water |
C. | provide additional water flow |
D. | none of the above |
Answer» A. cool the jacket water |
18. |
Thermostat is used in radiators to |
A. | control the velocity of water |
B. | control distribution of water to various cylinders |
C. | control the water temperature |
D. | control the pressure of water |
Answer» C. control the water temperature |
19. |
As the compression ratio increases, there is a |
A. | large increase in heat rejection |
B. | large decrease in heat reduction |
C. | marginal increase in heat rejection |
D. | marginal reduction in heat rejection |
Answer» D. marginal reduction in heat rejection |
20. |
Spark timing other than minimum spark advance for best torque (MBT) results in |
A. | less heat rejection |
B. | more beat rejection |
C. | no effect on heat rejection |
D. | none of the above |
Answer» B. more beat rejection |
21. |
Direct system of cooling air is one which |
A. | cooling water flows by gravity |
B. | hot water is continuously cooled and circulated |
C. | hot water is simply discharged |
D. | water is allowed to evaporate in the cylinder jacket |
Answer» C. hot water is simply discharged |
22. |
In evaporate cooling systems, heat absorbed per kg of coolant air is equal to |
A. | Cp Δ t |
B. | Cv Δ t |
C. | latent heat of the coolant |
D. | (Cp – Cv) Δ t |
Answer» C. latent heat of the coolant |
23. |
Pump used in the forced cooling system is normally |
A. | piston pump |
B. | gear pump |
C. | vane pump |
D. | centrifugal pump |
Answer» D. centrifugal pump |
24. |
Limitations of air cooling systems are |
A. | applicable only to large engines |
B. | cooling is fast |
C. | higher working temperature compared to water cooling |
D. | all of the above |
Answer» C. higher working temperature compared to water cooling |
25. |
Which is more viscous lib oil |
A. | SEA 30 |
B. | SAE 40 |
C. | SAE 50 |
D. | SAE 80. |
Answer» D. SAE 80. |
26. |
In a naturally aspirated diesel engine, the air is supplied by |
A. | a supercharger |
B. | a centrifugal blower |
C. | a vacuum chamber |
D. | an injection tube |
Answer» C. a vacuum chamber |
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