Practice Test: Question Set - 02
1. If the temperature of intake air in internal combustion engine increases, then its efficiency will
- (A) Remain same
- (B) Decrease
- (C) Increase
- (D) None
of these
2. The operation of forcing additional air under pressure in the engine cylinder is known as
- (A) Scavenging
- (B) Turbulence
- (C) Supercharging
- (D) Pre-ignition
3. The ignition quality of petrol is expressed by
- (A) Cetane
number
- (B) Octane
number
- (C) Calorific
value
- (D) All
of these
4. The mean effective pressure obtained from engine indicator indicates the
- (A) Maximum pressure
developed
- (B) Minimum pressure
- (C) Instantaneous
pressure at any instant
- (D) Average pressure
5. The probability of knocking in diesel engines is increased by
- (A) High
self ignition temperature
- (B) Low
volatility
- (C) Higher
viscosity
- (D) All
of these
6. Pour point of fuel oil is the
- (A) Minimum 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
- (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
7. In a four stroke cycle petrol engine, the compression
- (A) Starts at
40° after bottom dead centre and ends at 30° before top dead centre
- (B) Starts
at 40° before bottom dead centre and ends at 30° after bottom dead centre
- (C) Starts
at bottom dead centre and ends at top dead centre
- (D) May
start and end anywhere
8. The maximum temperature in the I.C. engine cylinder is of the order of
- (A) 500-1000°C
- (B) 1000-1500°C
- (C) 1500-2000°C
- (D) 2000-2500°C
9. In compression ignition engines, swirl denotes a
- (A) Haphazard
motion of the gases in the chamber
- (B) Rotary
motion of the gases in the chamber
- (C) Radial
motion of the gases in the chamber
- (D) None
of the above
10. 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 loads
- (D) Supplying compressed
air to remove combustion products fully
11. The knocking in spark ignition engines can be reduced by
- (A) Retarding
the spark
- (B) Increasing
the engine speed
- (C) Both
(A) and (B)
- (D) None
of these
12. 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.
13. In a four stroke cycle diesel engine, the exhaust valve
- (A) Opens
at 30° before bottom dead centre and closes at 10° after top dead centre
- (B) Opens
at 30° after bottom dead centre and closes at 10° before top dead centre
- (C) Opens
at bottom dead centre and closes at top dead centre
- (D) May
open and close anywhere
14. The pressure at the end of compression in the case of diesel engine is of the order of
- (A) 6 kg/cm
- (B) 12 kg/cm
- (C) 20 kg/cm
- (D) 35 kg/cm
15. The fuels in order of decreasing knock tendency for spark ignition engines are
- (A) Paraffin,
aromatic, napthene
- (B) Paraffin,
napthene, aromatic
- (C) Napthene,
aromatics, paraffin
- (D) Napthene,
paraffin, aromatic
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