Practice Test: Question Set - 07
1. Which of the following fuel detonates readily?
- (A) Benzene
- (B) Iso-octane
- (C) Normal
heptane
- (D) Alcohol
2. In a typical medium speed 4-stroke cycle diesel engines
- (A) Exhaust valve opens
at 35° before bottom dead center and closes at 20° after top dead center
- (B) Exhaust valve opens
at bottom dead center and closes at top dead center
- (C) Exhaust valve opens
just after bottom dead center and closes just before top dead center
- (D) May open and close
anywhere
3. During idling, a petrol engine requires _________ mixture.
- (A) Lean
- (B) Rich
- (C) Chemically
correct
- (D) None
of these
4. The air-fuel ratio in petrol engines is controlled by
- (A) Controlling valve
opening/closing
- (B) Governing
- (C) Injection
- (D) Carburetion
5. The function of a distributor in a coil ignition system of I.C. engines is
- (A) To
distribute spark
- (B) To
distribute power
- (C) To
distribute current
- (D) To
time the spark
6. 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) 0.3 kg
7. In a four stroke cycle petrol engine, the expansion
- (A) Starts
at top dead center and ends at bottom dead center
- (B) Starts
at 30° before top dead center and ends at 50° before bottom dead center
- (C) Starts at
30° after top dead center and ends at 50° after bottom dead center
- (D) May
start and end anywhere
8. Which of the following is false statement?
Excess quantities of sulphur in diesel fuel
are Objectionable because it may cause the following
- (A) Piston ring and
cylinder wear
- (B) Formation of hard
coating on piston skirts
- (C) Oil sludge in the
engine crank case
- (D) Detonation
9. As compared to air standard cycle, in actual working, the effect of variation in specific heats is to
- (A) Increase
maximum pressure and maximum temperature
- (B) Reduce
maximum pressure and maximum temperature
- (C) Increase
maximum pressure and decrease maximum temperature
- (D) Decrease
maximum pressure and increase maximum temperature
10. Fuel consumption of diesel engines is not guaranteed at one quarter load because at such low loads
- (A) The friction is high
- (B) The friction is unpredictable
- (C) The small difference in cooling water
temperature or in internal friction has a disproportionate effect
- (D) The engine is rarely
operated
11. By higher octane number of spark ignition fuel, it is meant that the fuel has
- (A) Higher
heating value
- (B) Higher
flash point
- (C) Lower
volatility
- (D) Longer
ignition delay
12. In diesel engine the diesel fuel injected into cylinder would burn instantly at about compressed air temperature of
- (A) 250°C
- (B) 500°C
- (C) 1000°C
- (D) 2000°C
13. A gas engine has a swept volume of 300 cm3 and clearance volume of 25 cm3. Its volumetric efficiency is 0.88 and mechanical efficiency is 0.90. The volume of the mixture taken in per stroke is
- (A) 248 cm3
- (B) 252 cm3
- (C) 264 cm3
- (D) 286 cm3
14. In a typical medium speed 4-stroke cycle diesel engine
- (A) Compression starts at
35° after bottom dead center and ends at top dead center
- (B) Compression starts at
bottom dead center and ends at top dead center
- (C) Compression starts at
10° before bottom dead center and, ends just before top dead center
- (D) May start and end
anywhere
15. In a petrol engine, the mixture has the lowest pressure at the
- (A) Beginning
of suction stroke
- (B) End
of suction stroke
- (C) End
of compression stroke
- (D) None
of these
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