240 Important Internal Combustion Engines MCQ Question and Answer | PDF Free Download
1.A mixture containing 65% of iso-octane and 35% of normal heptane will have
- ACetane number 65
- BOctane number 65
- CCetane number 35
- DOctane number 35
2.In the opposed piston diesel engine, the combustion chamber is located
- AAbove the piston
- BBelow the piston
- CBetween the pistons
- DThere is no such criterion
3.A heat engine utilizes the
- ACalorific value of oil
- BLow heat value of
- CHigh heat value of oil
- DMean heat value of oil
4.Solid fuel fabricated into various small shapes, which are assembled to form fuel elements, is in the form of
- APlates
- BPallets
- CPins
- DAll of these
5.In a petrol engine, the fuel supplied to the engine cylinder is mixed with required quantity of air and the mixture is ignited with a
- AFuel pump
- BFuel injector
- CSpark plug
- DNone of these
6.Detonation is harmful due to
- AIncrease in the rate of heat transfer, there is a reduction in the power output and efficiency of the engine
- BExcessive turbulence which removes most of the insulating gas boundary layer from the cylinder walls
- CHigh intensity of knock causes crankshaft vibration and the engine runs rough
- DNone of the above
7.In diesel engine the diesel fuel injected into cylinder would burn instantly at about compressed air temperature of
- A250°C
- B500°C
- C1000°C
- D2000°C
8.In a naturally aspirated diesel engine, the air is supplied by
- AA supercharger
- BA centrifugal blower
- CA vacuum chamber
- DAn injection tube
9.In an internal combustion engine, the process of removing the burnt gases from the combustion chamber of the engine cylinder is known as
- AScavenging
- BDetonation
- CSupercharging
- DPolymerisation
10.The operation of forcing additional air under pressure into the engine cylinder is known as
- ASupercharging
- BCarburetion
- CTurbulence
- DDelay period
11.Installation of supercharger on a four cycle diesel engine can result in the following percentage increase in power
- AUp to 35%
- BUp to 50%
- CUp to 75%
- DUp to 100%
12.Volatility of diesel fuel oil is
- AMinimum temperature to which oil is heated in order to give off inflammable vapours in sufficient quantity to ignite momentarily when brought in contact with a flame
- BTemperature at which it solidifies or congeals
- CIt catches fire without external aid
- DIndicated by 90% distillation temperature, i.e., when 90% of sample oil has distilled off
13.The ratio of the indicated thermal efficiency to the air standard efficiency is known as
- AMechanical efficiency
- BOverall efficiency
- CVolumetric efficiency
- DRelative efficiency
14.The specific fuel consumption per B.P. hour for a petrol engine is about
- A0.2 kg
- B0.25 kg
- C0.3 kg
- D0.35 kg
15.The injection pressure in a diesel engine is about
- A10 bar
- B100 bar
- C150 bar
- D500 bar
16.The minimum cranking speed in case of petrol engine is about
- AHalf the operating speed
- BOne fourth of operating speed
- C250 - 300 rpm
- D60 - 80 rpm
17.If the compression ratio in I.C. engine increases, then its thermal efficiency will
- ADecrease
- BIncrease
- CRemain same
- DNone of these
18.Pre-ignition is caused by the spontaneous combustion of the mixture before the end of the compression stroke, and is due to
- ACylinder walls being too hot
- BOverheated spark plug points
- CRed hot carbon deposits on cylinder walls
- DAny one of these
19.Supercharging is the process of supplying the intake air to the engine cylinder at a density _________ the density of the surrounding atmosphere.
- AEqual to
- BLess than
- CGreater than
- DNone of these
20.The brake power of a diesel engine, keeping other parameters constant, can be increased by
- ADecreasing the density of intake air
- BIncreasing the temperature of intake air
- CIncreasing the pressure of intake air
- DDecreasing the pressure of intake air