Power Plant Engineering Multiple Choice Questions on “Diesel Engine Basics”.
1. If the temperature of intake air in internal combustion engine increases, then its efficiency will __________
a) remain same
b) increase
c) decrease
d) none of the mentioned
Answer: c
Clarification: The efficiency of an IC Engine is inversely proportional to the temperature of intake air.
2. The operation of forcing additional air under pressure in the engine cylinder is known as __________
a) Supercharging
b) Scavenging
c) Turbulence
d) Pre-ignition
Answer: a
Clarification: Supercharging is the operation of forcing additional air under pressure in the engine cylinder.
3. The ignition quality of petrol is expressed by __________
a) Cetane number
b) Octane number
c) Calorific Value
d) None of the mentioned
Answer: b
Clarification: Octane number estimates the quality of petrol.
4. The mean effective pressure obtained from engine indicator indicates the __________
a) maximum pressure developed
b) minimum pressure developed
c) instantaneous pressure at any point
d) average pressure
Answer: d
Clarification: The mean effective pressure indicates the average pressure on the engine.
5. The probability of knocking in diesel engines is increased by __________
a) high self-ignition temperature
b) low volatility
c) high viscosity
d) all of the mentioned
Answer: d
Clarification: The probability of knocking in diesel engines is increased by keeping high self-ignition temperature, low volatility, high viscosity, etc.
6. Reactors for propulsion applications are designed for__________
a) any form of uranium
b) natural uranium
c) enriched uranium
d) thorium
Answer: c
Clarification: Enriched uranium is the material that is used for making reactors for propulsion application.
7. What is the pour point of fuel oil?
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
Answer: b
Clarification: The temperature at which fuel oil solidifies or congeals is called pour point of fuel oil.
8. What is the maximum temperature in the I.C. engine cylinder is of the order of(in degree Celsius)?
a) 500-1000
b) 1000-1500
c) 1500-2000
d) 2000-2500
Answer: d
Clarification: The maximum temperature in the I.C. engine cylinder is of the order of(in degree Celsius) is 2000-25000 degree Celsius.
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 mentioned
Answer: b
Clarification: Swirl in a compression ignition engine denotes rotary motion of the gases in the chamber.
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) Supplying compressed air to remove combustion products fully
c) Providing excess temperature to the sucked in gases
d) None of the mentioned