250+ TOP MCQs on Fuel Supply System in Ignition or Diesel Engine and Answers

This set of Farm Machinery Multiple Choice Questions on “Fuel Supply System in Ignition or Diesel Engine”.

1. The common fuels for I.C. engines are _____________
a) Petrol and diesel
b) Petrol, power kerosene, light speed diesel and high-speed diesel
c) Kerosene and diesel
d) Petrol and kerosene
Answer: b
Explanation: Fuel is consumed by the engine in order to produce energy. The common fuel for I.C. engines is light diesel oil (22 API degree), high-speed diesel (31 API degree), petrol kerosene (40 API degree), Petrol (13 API Degree).

2. Specific gravity of LDO is ____________
a) 0.10
b) 1.325
c) 0.920
d) 1.05
Answer: c
Explanation: LDO – 22 API Degree, 0.920 Specific Degree, 10300 Calorific Value.

3. Quality of the fuel is judged by its ____________
a) Calorific value
b) Power conversion
c) Loss to cool the engine
d) Consumption
Answer: a
Explanation: The quality of the fuel mainly depends upon the volatility of fuel. Calorific value of fuel is the heat liberated by combustion of a fuel.

4. Vapor lock is associated to the ____________
a) Cooling system of engine
b) Ignition system of engine
c) Fuel supply system of engine
d) Governor system of engine
Answer: c
Explanation: Vapor lock is a problem that affects gasoline-fuelled IC engines. It happens when the fuel changes state from liquid to gas while still in the fuel delivery system.

5. Volatility of fuel affects the ____________
a) Engine speed
b) Efficiency
c) Consumption rate
d) Engine power
Answer: a
Explanation: Volatility of fuel has considerable effect on the performance of the engine by affecting- ease of starting the engine, degree of crankcase oil dilution, formation of vapour lock in the fuel system, accelerating characteristics of the engine.

6. In engine cylinder, the petrol is vaporised ____________
a) Quicker than HSD
b) Quicker than water
c) Slow than HSD
d) Slow than water
Answer: a
Explanation: Vaporising temperature of high-speed oil is higher than that of the petrol, hence petrol vaporises quicker than diesel oil in the engine cylinder. This help in easy starting of petrol engines.

7. Octane number is associated to ____________
a) Fuel consumption
b) Ignition quality of fuel
c) Fuel supply system
d) Fuel delivery
Answer: b
Explanation: Ignition quality is the ease of burning the oil in the combustion chamber. Octane number and cetane number are the measures of ignition quality of the fuel.

8. The knock characteristics of fuel is indicated by ____________
a) Cetane number
b) Octane number
c) Calorific value
d) Fuel consumption
Answer: b
Explanation: Octane number is the calculation of knock characteristics of a fuel. The percentage of C8H18 in the reference fuel consisting of a mixture of iso-octane and normal heptane C7H16 when is produces the same knocking effect as the fuel under test is called octane number.

9. Diesel fuel are rated by ____________
a) Octane number
b) Cetane number
c) Calorific value
d) Engine efficiency
Answer: b
Explanation: Diesel fuels are rated according to cetane number which is the indication of ignition quality of fuel. The higher the cetane number the better the ignition quality of the fuel.

10. Detonation refers to ____________
a) Engine knocking
b) Air locking
c) Poor ignition
d) Fuel properties
Answer: a
Explanation: Detonation refers to violent noises, heard in on engine, giving pinging sound during the process of combustion. It occurs during the process of combination of the mixture within the cylinder after ignition has taken place.

11. The formula of API degree is _______
a) (frac{141.5}{specific, gravity ,of ,oil, at, 60℉}) – 13.15
b) Specific gravity of oil-13.5
c) (frac{141.5}{specific, gravity ,of, oil})+131.5
d) (frac{specifc gravity of oil+41.31}{141.5} )
Answer: a
Explanation: API gravity of water is 10. A high API gravity fail generally releases more heat per unit mass and vice versa for per unit volume.

12. A four-stroke diesel engine operating at 800 rpm uses 0.10 kg of fuel in 4 minutes while developing a torque of 70 Nm. Calculate brake specific fuel consumption
a) 0.262 kg/kwh
b) 0.256 kg/kwh
c) 0.242 kg/kwh
d) 0.236 kg/kwh
Answer: b
Explanation: Power=(frac{2πNT}{60}=frac{2*π*800*70}{60}) = 5864.31 W
Brake specific fuel consumption = (frac{0.10*60}{4*5.86}) = 0.256 kg/kwh.

13. Find the weight of air for complete combustion of 10 l of petrol, assuming air contains 22.7%
a) 113.66 kg
b) 171 kg
c) 450.12 kg
d) 650 kg
Answer: a
Explanation: 10 l of petrol = 7300 g
2*86 g of petrol requires = 19*32 kg of oxygen
7300 g of petrol requires = (frac{19*32*7300}{2*86}) = 25.80 kg
Amount of air required = 25.80 * 100/22.7 = 113.66.

14. An IC engine consumes high speed diesel oil at the rate of 0.5 kg/h. Calculate the power of the engine.
a) 10 KW
b) 15.45 KW
c) 6.15 KW
d) 22.15 KW
Answer: c
Explanation: Heat volume = mass flow rate of fuel * calorific value = 0.5*10550 = 5275 kcal/hr
5275 kcal/h = 5275*4.2 k joules/hr = (frac{5275*4.2*1000}{6154.167} )
Power of engine = 6.15 KW.

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