Mechanical Engineering

Question: The auto ignition in a spark ignition engine means
[A].

automatic ignition of the charge at the end of compression

[B].

ignition induced by the passage of a spark

[C].

ignition of the charge before the passage of flame front

[D].

ignition induced to supplement the process of normal combustion

Answer: Option C

Explanation:

No answer description available for this question.

Question: In case of a Diesel car, the pressure at the end of compression is of the order of
[A].

15 bar

[B].

25 bar

[C].

35 bar

[D].

45 bar

Answer: Option D

Explanation:

No answer description available for this question.

Question: If the air-fuel mixture in a spark ignition engine is too rich, then air-fuel ratio is about
[A].

17:1

[B].

15:1

[C].

13:1

[D].

10:1

Answer: Option D

Explanation:

No answer description available for this question.

Question: One effect of detonation is
[A].

delay in ignition

[B].

loss of power

[C].

overheating of engine

[D].

overcooling of engine

Answer: Option B

Explanation:

No answer description available for this question.

Question: If the air-fuel mixture ignites before the spark takes place at spark plug, the condition is called
[A].

detonation

[B].

ignition

[C].

pre-ignition

[D].

rumble

Answer: Option C

Explanation:

No answer description available for this question.

Question: The boiling point of Diesel fuel is in the range of
[A].

70°C to 100°C

[B].

100°C to 120°C

[C].

120°C to 180°C

[D].

180°C to 360 °C

Answer: Option D

Explanation:

No answer description available for this question.

Question: The calorific value of Diesel is about
[A].

36.5 MJ/kg

[B].

38.5 MJ/kg

[C].

42.5 MJ/kg

[D].

45.5 MJ/kg

Answer: Option D

Explanation:

No answer description available for this question.

Question: The calorific value of petrol is about
[A].

36.5 – 38.5 MJ/kg

[B].

39.4 – 42.5 MJ/kg

[C].

42.7 – 43.5 MJ/kg

[D].

45.5 – 47 MJ/kg

Answer: Option C

Explanation:

No answer description available for this question.

Question: In Diesel engines, the duration between the time of injection and the time of ignition is called
[A].

spill cut-off

[B].

delay period

[C].

injection period

[D].

ignition period

Answer: Option B

Explanation:

No answer description available for this question.

Question: A petrol that detonates easily is called
[A].

high octane petrol

[B].

low octane petrol

[C].

unleaded petrol

[D].

blended fuel

Answer: Option B

Explanation:

No answer description available for this question.