I.C Engines Online Practice Test - Set 03

Practice Test: Question Set - 03

1. Crankcase explosion in I.C. engines usually occurs as
    (A) First a mild explosion followed by a bi explosion
    (B) First a big explosion followed by a mil explosion
    (C) Both mild and big explosions occurs simultaneously
    (D) Never occurs

2. The air requirement of a petrol engine during starting compared to theoretical air required for complete combustion is
    (A) More
    (B) Less
    (C) Same
    (D) May be more or less depending on engine capacity

3. In a four stroke cycle diesel engine, the compression
    (A) Starts at 40° after bottom dead center and ends at 10° before top dead center
    (B) Starts at 40° before top dead center and ends at 40° after top dead center
    (C) Starts at top dead center and ends at 40° before bottom dead center
    (D) May start and end anywhere

4. It the temperature of intake air in IC engines is lowered, then its efficiency will
    (A) Increase
    (B) Decrease
    (C) Remain same
    (D) Increase up to certain limit and then decrease

5. The loud pulsating noise heard within the cylinder of an internal combustion engine is known as
    (A) Detonation
    (B) Turbulence
    (C) Pre-ignition
    (D) Supercharging

6. Which of the following medium is compressed in a Diesel engine cylinder?
    (A) Air alone
    (B) Air and fuel
    (C) Air and lub oil
    (D) Fuel alone

7. Detonation is harmful due to
    (A) Increase in the rate of heat transfer, there is a reduction in the power output and efficiency of the engine
    (B) Excessive turbulence which removes most of the insulating gas boundary layer from the cylinder walls
    (C) High intensity of knock causes crankshaft vibration and the engine runs rough
    (D) None of the above

8. A stoichiometric air-fuel ratio is
    (A) Chemically correct mixture
    (B) Lean mixture
    (C) Rich mixture for idling
    (D) Rich mixture for over loads

9. The firing order in an I.C. engine depends upon
    (A) Arrangement of the cylinders
    (B) Design of crankshaft
    (C) Number of cylinders
    (D) All of these

10. Pick up the false statement
    (A) Thermal efficiency of diesel engine is about 34%
    (B) Theoretically correct mixture of air and petrol is approximately 15:1
    (C) High speed compression engines operate on dual combustion cycle
    (D) S.I. engines are quality governed engines

11. The maximum propulsive efficiency of a turbojet engine is at a speed of
    (A) 1000 km/h
    (B) 2000 km/h
    (C) 2400 km/h
    (D) 3000 km/h

12. 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

13. The inlet valve of a four stroke cycle internal combustion engine remains open for
    (A) 130°
    (B) 180°
    (C) 230°
    (D) 270°

14. The minimum cranking speed in case of petrol engine is about
    (A) Half the operating speed
    (B) One fourth of operating speed
    (C) 250 - 300 rpm
    (D) 60 - 80 rpm

15. Number of working strokes per min. for a two stroke cycle engine is _________ the speed of the engine in r.p.m.
    (A) Equal to
    (B) One-half
    (C) Twice
    (D) Four-times

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Internal Combustion Engines (I.C. Engines):
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