Practice Test: Question Set - 13
1. In a four stroke cycle petrol engine, the pressure inside the engine cylinder during the suction stroke is __________ the atmospheric pressure.
- (A) Equal to
- (B) Below
- (C) Above
- (D) None
of these
2. Diesel fuel, compared to petrol is
- (A) Less difficult to
ignite
- (B) Just about the same
difficult to ignite
- (C) More difficult to
ignite
- (D) Highly ignitable
3. In a petrol engine, if diesel is used, then the engine will
- (A) Not run
- (B) Run
more efficiently
- (C) Run
at high speed
- (D) Explode
4. Installation of supercharger on a four cycle diesel engine can result in the following percentage increase in power
- (A) Up to 35%
- (B) Up to 50%
- (C) Up to 75%
- (D) Up to 100%
5. The thermal efficiency of diesel engines on weak mixtures is
- (A) Unaffected
- (B) Lower
- (C) Higher
- (D) Dependent
on other factors
6. Combustion in compression ignition engines is
- (A) Homogeneous
- (B) Heterogeneous
- (C) Both (A) and (B)
- (D) Laminar
7. The colour of exhaust from diesel engine is generally
- (A) White
- (B) Bluish
- (C) Black
- (D) Violet
8. A diesel engine as compared to petrol engine (both running and rated load) is
- (A) More efficient
- (B) Less efficient
- (C) Equally efficient
- (D) Other factors will decide it
9. In a four stroke cycle petrol engine, the charge is ignited at
- (A) 30°
before top dead center
- (B) 30°
after top dead center
- (C) 30°
before bottom dead center
- (D) 30°
after bottom dead center
10. In case of gas turbines, the gaseous fuel consumption guarantees are based on
- (A) High heat value
- (B) Low heat value
- (C) Net calorific value
- (D) Calorific value
11. The knocking tendency in spark ignition engines may be decreased by
- (A) Controlling
the air-fuel mixture
- (B) Controlling
the ignition timing
- (C) Controlling
the exhaust temperature
- (D) Reducing
the compression ratio
12. The term scavenging is generally associated with
- (A) 2-stroke cycle engines
- (B) 4-stroke cycle
engines
- (C) Aeroplane engines
- (D) High efficiency
engines
13. Which of the following statement is correct regarding normal cetane?
- (A) It
is a standard fuel used for knock rating of diesel engines
- (B) Its
chemical name is normal hexadecane
- (C) It has
long carbon chain structure
- (D) All of the
above
14. Most high speed compression engines operate on
- (A) Otto cycle
- (B) Diesel cycle
- (C) Dual cycle
- (D) Carnot cycle
15. In a four stroke cycle diesel engine, the inlet valve
- (A) Opens
at 20° before top dead center and closes at 40° after bottom dead center
- (B) Opens
at 20° after top dead center and closes at 20° before bottom dead center
- (C) Opens
at top dead center and closes at bottom dead center
- (D) May
open and close anywhere
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