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Internal Combustion Engines MCQ

Internal Combustion Engines MCQ Question and Answer

1.The scavenging efficiency of a four stroke cycle diesel engine is

  • ABelow 50%
  • BBetween 50 and 85%
  • CBetween 85 and 95%
  • DBetween 95 and 100%
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Correct Answer : (D)

Between 95 and 100%

Explanation:

2.Scavenging is usually done to increase

  • AThermal efficiency
  • BSpeed
  • CPower output
  • DFuel consumption
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Correct Answer : (C)

Power output

Explanation:

3.Which of the following medium is compressed in a Diesel engine cylinder?

  • AAir alone
  • BAir and fuel
  • CAir and lub oil
  • DFuel alone
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Correct Answer : (A)

Air alone

Explanation:

4.Number of working strokes per min. for a four stroke cycle engine are _________ the speed of the engine in r.p.m.

  • AEqual to
  • BOne-half
  • CTwice
  • DFour-times
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Correct Answer : (B)

One-half

Explanation:

5.Number of working strokes per min. for a two stroke cycle engine are _________ the speed of the engine in r.p.m.

  • AEqual to
  • BOne-half
  • CTwice
  • DFour-times
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Correct Answer : (A)

Equal to

Explanation:

6.The pressure at the end of compression, in diesel engines, is approximately

  • A10 bar
  • B20 bar
  • C25 bar
  • D35 bar
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Correct Answer : (D)

35 bar

Explanation:

7.The pressure at the end of compression, in petrol engines, is approximately

  • A10 bar
  • B20 bar
  • C25 bar
  • D35 bar
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Correct Answer : (A)

10 bar

Explanation:

8.Air fuel ratio for idling speed of a petrol engine is approximately

  • A1 : 1
  • B5 : 1
  • C10 : 1
  • D15 : 1
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Correct Answer : (C)

10 : 1

Explanation:

9.The specific fuel consumption per BH hour for a petrol engine is approximately

  • A0.15 kg
  • B0.2 kg
  • C0.25 kg
  • D0.3 kg
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Correct Answer : (C)

0.25 kg

Explanation:

10.Engine pistons are usually made of aluminium alloy because it

  • AIs lighter
  • BWear is less
  • CAbsorbs shocks
  • DIs stronger
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Correct Answer : (A)

Is lighter

Explanation:

11.The reason for supercharging in any engine is to

  • AIncrease efficiency
  • BIncrease power
  • CReduce weight and bulk for a given output
  • DEffect fuel economy
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Correct Answer : (C)

Reduce weight and bulk for a given output

Explanation:

12.Morse test can be conducted for

  • APetrol engines
  • BDiesel engines
  • CMulti cylinder engines
  • DAll of these
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Correct Answer : (C)

Multi cylinder engines

Explanation:

13.The cetane (C₁₆H₃₄) which is a straight chain paraffin, is assigned a cetane number of

  • A0
  • B50
  • C100
  • D150
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Correct Answer : (C)

100

Explanation:

14.Alpha-methyl-naphthalene (C₁₁ H₁₀) has a cetane number of

  • A0
  • B50
  • C100
  • D150
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Correct Answer : (A)

0

Explanation:

15.The specific fuel consumption per BHP hour for diesel engine is approximately

  • A0.15 kg
  • B0.2 kg
  • C0.25 kg
  • D0.3 kg
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Correct Answer : (B)

0.2 kg

Explanation:

16.The maximum propulsive efficiency of a turbojet engine is at a speed of

  • A1000 km/h
  • B2000 km/h
  • C2400 km/h
  • D3000 km/h
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Correct Answer : (C)

2400 km/h

Explanation:

17.The method of determination of indicated power of a multi cylinder spark ignition engine is by the use of

  • AMorse test
  • BProny brake test
  • CMotoring test
  • DHeat balance test
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Correct Answer : (A)

Morse test

Explanation:

18.The air-fuel ratio of the petrol engine is controlled by

  • AFuel pump
  • BGovernor
  • CInjector
  • DCarburettor
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Correct Answer : (D)

Carburettor

Explanation:

19.The air-fuel ratio in petrol engines is controlled by

  • AControlling valve opening/closing
  • BGoverning
  • CInjection
  • DCarburetion
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Correct Answer : (D)

Carburetion

Explanation:

20.A spark plug gap is kept from

  • A0.3 to 0.7 mm
  • B0.2 to 0.8 mm
  • C0.4 to 0.9 mm
  • D0.6 to 1.0 mm
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Correct Answer : (A)

0.3 to 0.7 mm

Explanation: