250+ TOP MCQs on Internal Combustion Engine and Answers

Automotive Engine Components Design Multiple Choice Questions on “Internal Combustion Engine”.

1. What is an internal combustion engine?
a) An engine that absorbs power by burning air+ water in a closed chamber
b) An engine that generates power by burning air+ fuel in a closed chamber
c) An engine that generates power by burning air+ fuel in an open chamber
d) An engine that absorbs power by burning air+ water in an open chamber
Answer: b
Clarification: Internal combustion engines are the engine that generates power by burning air and fuel (petrol, diesel, kerosene, etc..) in a closed chamber. Nothing can burn in the presence of water because water is a fire extinguisher.

2. What is the idling RPM of a motorcycle petrol engine?
a) 1200RPM
b) 700RPM
c) 18000RPM
d) 60RPM
Answer: a
Clarification: Idling RPM of a petrol engine is 1200 and for diesel engines, it is 700, whereas 18000 RPM is maximum RPM for superbike and 60 doesn’t exist.

3. Anything which burns in the presence of ______ is known as combustion.
a) water
b) fuel
c) air
d) salt
Answer: c
Clarification: Fuel(solid, liquid or gas) always need oxygen to get combusted and the air is the only source for the availability of oxygen. Hence, anything which burns in the presence of air is known as combustion.

4. What was used as fuel during the early invention of IC engines?
a) Gun-powder
b) Petrol
c) Potassium
d) Kerosene
Answer: a
Clarification: In the 1600s, Gun powder was available as explosive, Huygen invented and engine that uses gunpowder as the fuel. Petrol and kerosene didn’t exist in those days and potassium is not used in the engine till today.

5. Otto cycle is used in which engine?
a) External combustion engine
b) Petrol engine
c) Diesel engine
d) Steam engine
Answer: b
Clarification: Otto cycle explains the working of a petrol engine for each stroke that takes place. The diesel engine uses a diesel cycle. The steam engine is a part of the external combustion engine and they don’t follow the Otto cycle.

6. Who invented the first car which used gasoline as fuel?
a) Rudolf Diesel
b) Nikola Tesla
c) Nikolaus Otto
d) Karl Benz
Answer: d
Clarification: Karl Benz invented the first car which used gasoline/petrol as fuel. Rudolf diesel discovered diesel and Nikolaus Otto discovered petrol engine. Nikola Tesla discovered AC.

7. How many power strokes are produced in a 4-stroke diesel engine running at 1500RPM?
a) 750
b)1500
c) 1000
d) 375
Answer: a
Clarification: In a 4-stroke engine the power stroke is produced in every two rotation of the crankshaft.
Number of power strokes=(frac{RPM}{number , of , crank , rotation , for , one , complete , rotation , of , the , flywheel})
Hence, (frac{1500}{2}=750)

8. Which of the mentioned below is not a component of the IC engine?
a) Piston
b) Cylinder
c) Wheel
d) Spark plug
Answer: c
Clarification: Piston, Cylinder, Spark plug are the components of the IC engine whereas the wheel absorbs the power from the IC engine and produces a tractive force that helps in moving the vehicle.

9. The black smoke coming out of a petrol engine is due to what particles?
a) Oxygen molecules
b) Magnesium particles
c) Nitrox
d) Carbon particles
Answer: d
Clarification: The black smoke is due to the presence of carbon particles which is formed because of incomplete combustion caused by less amount of air to the supplied fuel.

10. Which is the first company to use assembly line mode for the production of cars?
a) Fiat
b) Mercedes Benz
c) Ford
d) Volvo
Answer: c
Clarification: Henry ford in the year 1908 started the first mass production of car Model T using assembly line mode of production. Benz invented the first car. Fiat and Volvo emerged later on in the automotive industry.

11. Which of the mentioned below is the external combustion engine?
a) Wankel engine
b) Steam engine
c) Petrol engine
d) VTEC engine
Answer: b
Clarification: The Steam engine is an example of an external combustion engine that uses steam as the working fluid to produce energy. The steam is produced externally by burning coal.

12. Who invented the Compression ignition engine?
a) Issac Newton
b) Rudolf Diesel
c) Nikolaus August Otto
d) Albert Einstein
Answer: b
Clarification: The compression ignition engine is also known as the Diesel engine and it was invented by Rudolf diesel in the 1890s. Nikolaus August Otto invented the SI engine. Issac Newton defined forces and Albert Einstein worked in the field of space and light.

13. What is the compression ratio of the Diesel engine?
a) 15:1 to 23:1
b) 9:1 to 14:1
c) 1:15 to 1:23
d) 1:9 to 1:14
Answer: a
Clarification: The compression ignition has no spark plug to ignite the fuel. So, the charge is compressed to high pressure to self-ignite and the compression ratio ranges from 15:1 to 23:1.

14. The Wankel engine is also called a Rotary engine.
a) True
b) False
Answer: a
Clarification: The Wankel engine uses an eccentric rotary design to convert power to Rotary motion. Hence, the Wankel engine is also called a rotary engine.

15. What is the stoichiometric ratio of the Air + Gasoline mixture?
a) 14.5:1
b) 1:14.5
c) 14.7:1
d) 14.3:1
Answer: c
Clarification: The stoichiometric ratio of Air + Gasoline mixture is 14.7:1 which means 14.7 parts of air are required to burn 1 part of the fuel.

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