Which of the following is false statement. Some of the methods used to reduce diesel smoke are as follows ________________?

adherence to proper fuel specification

engine derating i.e. reducing the maxi-mum flow of fuel

increasing the compression ratio

adherence to proper fuel specification

Which is false statement about advantages of V-type engine_________________?

compact design requiring lesser space

improved distribution of air to cylinder

casting less liable to distortion

reduced torsional vibration because of shorter crankshaft

Which is correct statement about reaction time for autoignition of fuel and the fuel air ratio__________________?

lean mixture has high reaction time

rich mixture has high reaction time

chemically correct mixture has mini-mum reaction time

Volatility of diesel fuel oil is_________________?

temperature at which it flows easily

minimum temperature to which oil is heated in order to give off inflammable vapours in sufficient quantity to ignite momentarily when brought in conta

temperature at which it solidifies or congeals

it catches fire without external aid

indicated by 90% distillation temperature, i.e., when 90% of sample oil has distilled off

temperature at which it flows easily

The thermal efficiency of a two cycle engine as compared to four cycle engine is_________________?

more upto some load and then less

it may be less or more depending on several other factors

The thermal efficiency of a semi-diesel cycle having fixed compression ratio and fixed quantity of heat, with increase in pressure ratio will_______________?

increase/decrease depending upon engine capacity

first increase and then decrease

The thermal efficiecny of a diesel cycle having fixed compression ratio, with increase in cut-off ratio will___________________?

may increase or decrease depending on other factors

The system of lubrication used for motor cycles and scooters is by________________?

mixing about 5% lub oil with petrol

The specific fuel consumption of a petrol engine compared to diesel engine of same H.P. is_______________?

less or more depending on operating conditions

The size of inlet valve of.an engine in comparison to exhaust valve is_________________?

more/less depending on capacity of engine

The reason for supercharging in any engine is to________________?

reduce weight and bulk for a given out-put

The rating of a diesel engine, with increase in airintlet temperature, will ___________________?

first decrease linearly and then increase parabolically

The pressure and temperature at the end of compression stroke in a petrol engine are of the order of___________________?

12 – 20 kg/cm2 and 350 – 450°C

4 – 6 kg/cm2 and 200 – 250°C

6 – 12 kg/cm2 and 250 – 350°C

12 – 20 kg/cm2 and 350 – 450°C

20 – 30 kg/cm2 and 450 – 500°C

30 – 40 kg/cm2 and 500 – 700°C

The pour point of diesel oil must be_________________?

lower than the coldest atmospheric temperature at which oil is to be pumped

The operation of forcing additional air under pressure in the engine cylinder is known as________________?

dissociation and carburretion of fuel

197 + Mcqs in IC Engines in Mechanical Engineering Questions Page 1 McqOptions

1.	With increase in engine speed, the ignition of spark in petrol engine has to be __________________?
A.	Unaltered
B.	Increased
C.	Decreased
D.	Advanced
Answer» E.

Discussion

2.	With increase in speed of vehicle, the back pressure will________________?
A.	decrease
B.	increase
C.	remain unalfected
D.	depend on other factors
E.	none of the above
Answer» C. remain unalfected

Discussion

3.	Which of the following medium is compressed in a Diesel engine cylinder __________________?
A.	air aione
B.	air and fuel
C.	air and lub oil
D.	fuel alone
E.	air, fuel and lub oil
Answer» B. air and fuel

Discussion

4.	Which of the following is the lightest and most volatile liquid fuel________________?
A.	diesel
B.	kerosene
C.	fuel oil
D.	gasoline
E.	lub oil
Answer» E. lub oil

Discussion

5.	Which of the following is not an interns combustion engine___________________?
A.	2-stroke petrol engine
B.	4-stroke petrol engine
C.	diesel engine
D.	gas turbine
E.	steam turbine
Answer» F.

Discussion

6.	Which of the following is false statement. Some of the methods used to reduce diesel smoke are as follows ________________?
A.	using additives in the fuel
B.	engine derating i.e. reducing the maxi-mum flow of fuel
C.	increasing the compression ratio
D.	adherence to proper fuel specification
E.	avoidance of overloading
Answer» D. adherence to proper fuel specification

Discussion

7.	Which of the following engines can work on very lean mixture__________________?
A.	S.I. engine
B.	C.I. engine
C.	two stroke engine
D.	four stroke engine
E.	all of the above
Answer» C. two stroke engine

Discussion

8.	Which is more viscous lub oil_________________?
A.	SEA 30
B.	SAE 4£
C.	SAE 50
D.	SAE 70
E.	SAE 80
Answer» F.

Discussion

9.	Which is false statement about advantages of V-type engine_________________?
A.	compact design requiring lesser space
B.	improved distribution of air to cylinder
C.	casting less liable to distortion
D.	reduced torsional vibration because of shorter crankshaft
E.	less overhead clearance
Answer» F.

Discussion

10.	Which is correct statement about reaction time for autoignition of fuel and the fuel air ratio__________________?
A.	lean mixture has high reaction time
B.	rich mixture has high reaction time
C.	chemically correct mixture has mini-mum reaction time
D.	all of the above
E.	non of the above
Answer» E. non of the above

Discussion

11.	When crude oil is heated, then which of the following hydrocarbon is given off first______________?
A.	kerosene
B.	gasoline
C.	paraffin
D.	diesel
E.	natural gas
Answer» F.

Discussion

12.	Volatility of diesel fuel oil is_________________?
A.	minimum temperature to which oil is heated in order to give off inflammable vapours in sufficient quantity to ignite momentarily when brought in conta
B.	temperature at which it solidifies or congeals
C.	it catches fire without external aid
D.	indicated by 90% distillation temperature, i.e., when 90% of sample oil has distilled off
E.	temperature at which it flows easily
Answer» E. temperature at which it flows easily

Discussion

13.	Violent sound pulsations within the cylinder of an I.C. engine are caused due to_________________?
A.	heavy turbulence
B.	improved scavenging
C.	heavy supercharging
D.	detonation
E.	preignition
Answer» E. preignition

Discussion

14.	To reduce the possibility of knock in the C.I. engines, the first elements of fuel and air should have_______________?
A.	high temperature
B.	high density
C.	short delay
D.	reactive mixture
E.	all of the above
Answer» F.

Discussion

15.	Theoretically, the following engine should have maximum efficiency________________?
A.	gas engine
B.	2-stroke S.I. engine
C.	4-stroke S.I. engine
D.	steam engine
E.	4-stroke C.I. engine
Answer» F.

Discussion

16.	The working cycle in case of four stroke engine is completed in following number of revolutions of crankshaft___________________?
A.	1/2
B.	1
C.	2
D.	4
E.	8
Answer» D. 4

Discussion

17.	The top piston ring nearer to the piston crown is known as_____________________?
A.	compression ring
B.	oil ring
C.	scrapper ring
D.	groove ring
E.	leading ring
Answer» B. oil ring

Discussion

18.	The thermal efficiency of a two cycle engine as compared to four cycle engine is_________________?
A.	more
B.	less
C.	same
D.	more upto some load and then less
E.	it may be less or more depending on several other factors
Answer» C. same

Discussion

19.	The thermal efficiency of a semi-diesel cycle having fixed compression ratio and fixed quantity of heat, with increase in pressure ratio will_______________?
A.	increase
B.	decrease
C.	remain unaffected
D.	increase/decrease depending upon engine capacity
E.	first increase and then decrease
Answer» B. decrease

Discussion

20.	The thermal efficiecny of a diesel cycle having fixed compression ratio, with increase in cut-off ratio will___________________?
A.	increase
B.	decrease
C.	be independent
D.	may increase or decrease depending on other factors
E.	none of the above
Answer» C. be independent

Discussion

21.	The thermal efficiency of a petrol engine of two stroke with crank case scavenging as compared to four stroke petrol engine with same comperssion ratio will be_____________________?
A.	higher
B.	lower
C.	same
D.	depends on size of engine
E.	unpredictable
Answer» C. same

Discussion

22.	The thermal efficiency of a diesel engine is of the order of_________________?
A.	92%
B.	68%
C.	52%
D.	34%
E.	25%
Answer» E. 25%

Discussion

23.	The theoretically correct mixture of air and petrol is approximately ________________?
A.	0.334027778
B.	0.500694444
C.	0.625694444
D.	0.834027778
Answer» D. 0.834027778

Discussion

24.	The theoretically correct air fuel ratio for petrol engine is of the order of___________________?
A.	6 : 1
B.	9 : 1
C.	12 : 1
D.	15 : 1
E.	20 : 1
Answer» E. 20 : 1

Discussion

25.	The termal efficiency of a petrol engine at design load is around_________________?
A.	90%
B.	50%
C.	40%
D.	30%
E.	15%.
Answer» E. 15%.

Discussion

26.	The term scavenging is generally associated with______________________?
A.	2-stroke cycle engines
B.	4-stroke cycle engines
C.	aeroplane engines
D.	diesel engines
E.	high efficiency engines
Answer» F.

Discussion

27.	The temperature of interior surface of cylinder wall in normal operation is not allowed to exceed____________________?
A.	80°C
B.	120°C
C.	180°C
D.	240°C
E.	320°C
Answer» D. 240°C

Discussion

28.	The system of lubrication used for motor cycles and scooters is by________________?
A.	forced lubrication system
B.	splash lubrication
C.	applying grease under pressure
D.	wet sump method
E.	mixing about 5% lub oil with petrol
Answer» F.

Discussion

29.	The specific gravity of diesel oil Is_________________?
A.	1
B.	0.7
C.	0.85
D.	0.5
E.	1.25
Answer» D. 0.5

Discussion

30.	The specific fuel consumption per BHP hour for diesel engine is approximately___________________?
A.	0.15 kg
B.	0.2 kg
C.	0.25 kg
D.	0.3 kg
E.	0.35 kg
Answer» C. 0.25 kg

Discussion

31.	The specific fuel consumption per BH hour for a petrol engine is approximately__________________?
A.	0.15 kg
B.	0.2 kg
C.	0.25 kg
D.	0.3kg
E.	0.35 kg
Answer» D. 0.3kg

Discussion

32.	The specific fuel consumption of a petrol engine compared to diesel engine of same H.P. is_______________?
A.	same
B.	more
C.	less
D.	less or more depending on operating conditions
E.	unpredictable
Answer» C. less

Discussion

33.	The specific fuel consumption for a petrol engine first decreases with increase in fuel air ratio and then increases with further increase in fuel air ratio. The minimum value occurs in the range of__________________?
A.	lean mixture
B.	chemically correct mixture
C.	rich mixture
D.	unpredictable
E.	none of the above
Answer» B. chemically correct mixture

Discussion

34.	The spark plug gap is normally maintained at________________?
A.	0.1 to 0.2 mm
B.	0.2 to 0.4 mm
C.	0.45 to 0.6 mm
D.	0.6 to 0.8 mm
E.	0.8 to 1 mm
Answer» D. 0.6 to 0.8 mm

Discussion

35.	The size of inlet valve of.an engine in comparison to exhaust valve is_________________?
A.	more
B.	less
C.	same
D.	more/less depending on capacity of engine
E.	varies from design to design
Answer» C. same

Discussion

36.	The self-ignition temperature of diesel oil compared to petrol is_________________?
A.	higher
B.	lower
C.	same
D.	depends on quality of fuel
E.	unpredictable
Answer» C. same

Discussion

37.	The reason for supercharging in any engine is to________________?
A.	increase efficiency
B.	increase power
C.	reduce weight and bulk for a given out-put
D.	effect fuel economy
E.	none of the above
Answer» D. effect fuel economy

Discussion

38.	The ratio of useful power; engine friction exhaust gas losses; cooling water, air and oil losses for a diesel engine is of the order of____________________?
A.	5:25:30:50
B.	25:35:5:35
C.	25:5:10:60
D.	40:30:15:15
E.	25:5:35:35
Answer» F.

Discussion

39.	The ratio of indicated thermal efficiency to the corresponding air standard cycle efficiency is called__________________?
A.	net efficiency
B.	efficiency ratio
C.	relative efficiency
D.	overall efficiency
E.	cycle efficiency
Answer» D. overall efficiency

Discussion

40.	The rating of a diesel engine, with increase in airintlet temperature, will ___________________?
A.	increase linearly
B.	decrease linearly
C.	increase parabolically
D.	decrease parabolically
E.	first decrease linearly and then increase parabolically
Answer» C. increase parabolically

Discussion

41.	The pressure at the end of compression in the case of diesel engine is of the order of___________________?
A.	6 kg/cm
B.	12kg/cmz
C.	20 kg/cmz
D.	27.5 kg/cmz
E.	35 kg/cm
Answer» F.

Discussion

42.	The pressure and temperature at the end of compression stroke in a petrol engine are of the order of___________________?
A.	4 – 6 kg/cm2 and 200 – 250°C
B.	6 – 12 kg/cm2 and 250 – 350°C
C.	12 – 20 kg/cm2 and 350 – 450°C
D.	20 – 30 kg/cm2 and 450 – 500°C
E.	30 – 40 kg/cm2 and 500 – 700°C
Answer» C. 12 – 20 kg/cm2 and 350 – 450°C

Discussion

43.	The precess of breaking up or a lipuid into fine droplets by spraying is called___________________?
A.	vaporisation
B.	carburetion
C.	ionisation
D.	injection
E.	atomisation
Answer» F.

Discussion

44.	The pour point of diesel oil must be_________________?
A.	lower than the coldest atmospheric temperature at which oil is to be pumped
B.	higher than above
C.	has no such relation
D.	more than 100°C
E.	none of the above
Answer» B. higher than above

Discussion

45.	The pistons are usually given a coating such as tin plating in order to________________?
A.	reduce weight
B.	conduct heat efficiently
C.	reduce possibility of scoring
D.	reduce friction
E.	increase lubrication effect
Answer» D. reduce friction

Discussion

46.	The part load efficiency of a carburettor is,___________________?
A.	Maximum
B.	Optimum
C.	Poor
D.	Constant
Answer» D. Constant

Discussion

47.	The output of a diesel engine can be increased without increasing the engine revolution or size in following way_________________?
A.	feeding more fuel
B.	increasing flywheel size
C.	heating incoming air
D.	scavenging
E.	supercharging
Answer» F.

Discussion

48.	The operation of forcing additional air under pressure in the engine cylinder is known as________________?
A.	scavenging
B.	turbulence
C.	supercharging
D.	pre-ignition
E.	dissociation and carburretion of fuel
Answer» D. pre-ignition

Discussion

49.	The most popular firing order in case of four cylinder in-line I.C. engine is__________________?
A.	1-2-3-4
B.	1-3-2-4
C.	1-4-2-3
D.	1-2-4-3
E.	1-3-4-
Answer» C. 1-4-2-3

Discussion

50.	The m.e.p. of a petrol engine first increases as the fuel air ratio is increased and then decreases on further increase in fuel air ratio. The M.E.P is maximum in the zone of________________?
A.	lean mixture
B.	chemically correct mixture
C.	rich mixture
D.	unpredictable
E.	none of the above
Answer» D. unpredictable

Discussion

Explore topic-wise MCQs in Mechanical Engineering Questions.

With increase in engine speed, the ignition of spark in petrol engine has to be __________________?

With increase in speed of vehicle, the back pressure will________________?

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

Which of the following is the lightest and most volatile liquid fuel________________?

Which of the following is not an interns combustion engine___________________?

Which of the following is false statement. Some of the methods used to reduce diesel smoke are as follows ________________?

Which of the following engines can work on very lean mixture__________________?

Which is more viscous lub oil_________________?

Which is false statement about advantages of V-type engine_________________?

Which is correct statement about reaction time for autoignition of fuel and the fuel air ratio__________________?

When crude oil is heated, then which of the following hydrocarbon is given off first______________?

Volatility of diesel fuel oil is_________________?

Violent sound pulsations within the cylinder of an I.C. engine are caused due to_________________?

To reduce the possibility of knock in the C.I. engines, the first elements of fuel and air should have_______________?

Theoretically, the following engine should have maximum efficiency________________?

The working cycle in case of four stroke engine is completed in following number of revolutions of crankshaft___________________?

The top piston ring nearer to the piston crown is known as_____________________?

The thermal efficiency of a two cycle engine as compared to four cycle engine is_________________?

The thermal efficiency of a semi-diesel cycle having fixed compression ratio and fixed quantity of heat, with increase in pressure ratio will_______________?

The thermal efficiecny of a diesel cycle having fixed compression ratio, with increase in cut-off ratio will___________________?

The thermal efficiency of a petrol engine of two stroke with crank case scavenging as compared to four stroke petrol engine with same comperssion ratio will be_____________________?

The thermal efficiency of a diesel engine is of the order of_________________?

The theoretically correct mixture of air and petrol is approximately ________________?

The theoretically correct air fuel ratio for petrol engine is of the order of___________________?

The termal efficiency of a petrol engine at design load is around_________________?

The term scavenging is generally associated with______________________?

The temperature of interior surface of cylinder wall in normal operation is not allowed to exceed____________________?

The system of lubrication used for motor cycles and scooters is by________________?

The specific gravity of diesel oil Is_________________?

The specific fuel consumption per BHP hour for diesel engine is approximately___________________?

The specific fuel consumption per BH hour for a petrol engine is approximately__________________?

The specific fuel consumption of a petrol engine compared to diesel engine of same H.P. is_______________?

The specific fuel consumption for a petrol engine first decreases with increase in fuel air ratio and then increases with further increase in fuel air ratio. The minimum value occurs in the range of__________________?

The spark plug gap is normally maintained at________________?

The size of inlet valve of.an engine in comparison to exhaust valve is_________________?

The self-ignition temperature of diesel oil compared to petrol is_________________?

The reason for supercharging in any engine is to________________?

The ratio of useful power; engine friction exhaust gas losses; cooling water, air and oil losses for a diesel engine is of the order of____________________?

The ratio of indicated thermal efficiency to the corresponding air standard cycle efficiency is called__________________?

The rating of a diesel engine, with increase in airintlet temperature, will ___________________?

The pressure at the end of compression in the case of diesel engine is of the order of___________________?

The pressure and temperature at the end of compression stroke in a petrol engine are of the order of___________________?

The precess of breaking up or a lipuid into fine droplets by spraying is called___________________?

The pour point of diesel oil must be_________________?

The pistons are usually given a coating such as tin plating in order to________________?

The part load efficiency of a carburettor is,___________________?

The output of a diesel engine can be increased without increasing the engine revolution or size in following way_________________?

The operation of forcing additional air under pressure in the engine cylinder is known as________________?

The most popular firing order in case of four cylinder in-line I.C. engine is__________________?

The m.e.p. of a petrol engine first increases as the fuel air ratio is increased and then decreases on further increase in fuel air ratio. The M.E.P is maximum in the zone of________________?