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Mechanical Engineering-I.C. Engines Important MCQ PDF
1. 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.
Ans: c
2. In a diesel engine, the fuel is ignited by
(a) spark
(b) injected fuel
(c) heat resulting from compressing air that is supplied for combustion
(d) ignition
(e) combustion chamber.
Ans: c
3. Scavenging air in diesel engine means
(a) air used for combustion sent under pres-sure
(b) forced air for cooling cylinder
(c) burnt air containing products of combustion
(d) air used for forcing burnt gases out of engine's cylinder during the exhaust period
(e) air fuel mixture.
Ans: d
4. Supercharging is the process of
(a) supplying the intake of an engine with air at a density greater than the density of the
surrounding atmosphere
(b) providing forced cooling air
(c) injecting excess fuel for raising more load
(d) supplying compressed air to remove combustion products fully
(e) raising exhaust pressure.
Ans: a
5. Does the supply of scavenging air at a density greater than that of atmosphere mean
engine is supercharged ?
(a) yes
(b) no
(c) to some extent
(d) unpredictable
(e) depends on other factors.
Ans: b
6. 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.
Ans: c
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7. Compression ratio of LC. engines is
(a) the ratio of volumes of air in cylinder before compression stroke and after compression
stroke
(b) volume displaced by piston per stroke and clearance volume in cylinder
(c) ratio of pressure after compression and before compression
(d) swept volume/cylinder volume
(e) cylinder volume/swept volume.
Ans: a
8. The air standard efficiency of an Otto cycle compared to diesel cycle for the given
compression ratio is
(a) same
(b) less
(c) more
(d) more or less depending on power rating
(e) unpredictable.
Ans: c
9. The calorific value of gaseous fuels is expressed in terms of
(a) kcal
(b) kcal/kg
(c) kcal/m2
(d) kcal/n?
(e) all of the above.
Ans: d
11. If the intake air temperature of I.C. engine increases, its efficiency will
(a) increase
(b) decrease
(c) remain same
(d) unpredictable
(e) depend on other factors.
Ans: b
12. All heat engines utilize
(a) low heat value of oil
(b) high heat value of oil
(c) net claorific value of oil
(d) calorific value of fuel
(e) all of the above.
Ans: a
13. An engine indicator is used to determine the following
(a) speed
(b) temperature
(c) volume of cylinder
(d) m.e.p. and I.H.P.
(e) BHP.
Ans: d
14. Fuel oil consumption guarantees for I .C. engine are usually based on
(a) low heat value of oil
(b) high heat value of oil
(c) net calorific value of oil
(d) calorific value of fuel
Mechanical Engineering-I.C. Engines Important MCQ PDF
1. 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.
Ans: c
2. In a diesel engine, the fuel is ignited by
(a) spark
(b) injected fuel
(c) heat resulting from compressing air that is supplied for combustion
(d) ignition
(e) combustion chamber.
Ans: c
3. Scavenging air in diesel engine means
(a) air used for combustion sent under pres-sure
(b) forced air for cooling cylinder
(c) burnt air containing products of combustion
(d) air used for forcing burnt gases out of engine's cylinder during the exhaust period
(e) air fuel mixture.
Ans: d
4. Supercharging is the process of
(a) supplying the intake of an engine with air at a density greater than the density of the
surrounding atmosphere
(b) providing forced cooling air
(c) injecting excess fuel for raising more load
(d) supplying compressed air to remove combustion products fully
(e) raising exhaust pressure.
Ans: a
5. Does the supply of scavenging air at a density greater than that of atmosphere mean
engine is supercharged ?
(a) yes
(b) no
(c) to some extent
(d) unpredictable
(e) depends on other factors.
Ans: b
6. 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.
Ans: c
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7. Compression ratio of LC. engines is
(a) the ratio of volumes of air in cylinder before compression stroke and after compression
stroke
(b) volume displaced by piston per stroke and clearance volume in cylinder
(c) ratio of pressure after compression and before compression
(d) swept volume/cylinder volume
(e) cylinder volume/swept volume.
Ans: a
8. The air standard efficiency of an Otto cycle compared to diesel cycle for the given
compression ratio is
(a) same
(b) less
(c) more
(d) more or less depending on power rating
(e) unpredictable.
Ans: c
9. The calorific value of gaseous fuels is expressed in terms of
(a) kcal
(b) kcal/kg
(c) kcal/m2
(d) kcal/n?
(e) all of the above.
Ans: d
11. If the intake air temperature of I.C. engine increases, its efficiency will
(a) increase
(b) decrease
(c) remain same
(d) unpredictable
(e) depend on other factors.
Ans: b
12. All heat engines utilize
(a) low heat value of oil
(b) high heat value of oil
(c) net claorific value of oil
(d) calorific value of fuel
(e) all of the above.
Ans: a
13. An engine indicator is used to determine the following
(a) speed
(b) temperature
(c) volume of cylinder
(d) m.e.p. and I.H.P.
(e) BHP.
Ans: d
14. Fuel oil consumption guarantees for I .C. engine are usually based on
(a) low heat value of oil
(b) high heat value of oil
(c) net calorific value of oil
(d) calorific value of fuel
