250+ TOP MCQs on Qualities of Fuel and Answers

IC Engines Multiple Choice Questions on “Qualities Of Fuel”

1. The rating of a diesel engine, with an increase in air inlet temperature, will ___________
a) increase linearly
b) decrease linearly
c) increase parabolically
d) decrease parabolically
Answer: b
Clarification: None.

2. The knock in diesel engine occurs due to ___________
a) instantaneous and rapid burning of the first part of the charge
b) instantaneous auto ignition of last part of charge
c) reduction of delay period
d) none of the mentioned
Answer: a
Clarification: None.

3. What is volatility of diesel fuel?
a) maximum temperature to which oil is heated in order to give off inflammable vapour in sufficient quantity to ignite momentarily when bought in contact with a flame
b) it catches fire without external aid
c) indicated by 90% distillation temperature
d) none of the mentioned
Answer: c
Clarification: None.

4. Violent sound pulsations within the cylinder of an I.C. engine are caused due to ___________
a) heavy turbulence
b) improved scavenging
c) detonation
d) pre-ignition
Answer: c
Clarification: None.

5. What is Auto-ignition temperature?
a) maximum temperature to which oil is heated in order to give off inflammable vapour in sufficient quantity to ignite momentarily when bought in contact with a flame
b) that at which it catches fire without external aid
c) indicated by 90% distillation temperature
d) none of the mentioned
Answer: b
Clarification: Auto-ignition temperature is defined as that temperature at which it catches fire without external aid while volatility of diesel fuel is indicated by 90% distillation temperature.

6. What is Ignition lag?
a) the time taken by fuel after injection to reach upto auto-ignition temperature
b) time before actual fuel injection and the pump plunger starts to pump fuel
c) time corresponding to actual injection and top dead center
d) none of the mentioned
Answer: a
Clarification: None.

7. The delay period in petrol engine is of the order of ___________
a) 0.001 sec
b) 0.002 sec
c) 0.01 sec
d) 0.1 sec
Answer: b
Clarification: None.

8. Detonation is caused by which of the following unstable compounds?
a) peroxides, aldehydes, and ketones
b) peroxides, aldehydes, oxides, and sulphides
c) aldehydes, oxides, and ketones
d) none of the mentioned
Answer: a
Clarification: Detonation is caused by peroxides, aldehydes, and ketones.

9. In order to prevent knock in the S.I. engines, the charge away from the spark plug should have ___________
a) low temperature
b) low density
c) rich mixture
d) all of the mentioned
Answer: d
Clarification: None.

10. To reduce the possibility of knock in C.I. engines, the first elements of fuel and air should have ___________
a) high temperature
b) high density
c) short delay
d) all of the mentioned
Answer: d
Clarification: None.

11. The detonation tendency in petrol engines for specified conditions of fuel rating, compression ratio, speed, etc, can be controlled by having ___________
a) smaller cylinder bore
b) bigger cylinder bore
c) medium cylinder bore
d) none of the mentioned
Answer: a
Clarification: None.

12. A fuel will detonate less if it has ___________
a) higher self ignition temperature
b) lower self ignition temperature
c) proper self ignition temperature
d) none of the mentioned
Answer: a
Clarification: None.

13. Ignition quality of diesel fuel oil is expressed by an index called ___________
a) octane number
b) cetane number
c) calorific value
d) none of the mentioned
Answer: b
Clarification: Cetane number is defined as the ignition quality of diesel fuel oil is expressed by an index.