I.C Engines Objective Questions with Answers – Set 01

Are you guys looking for Mechanical Engineering MCQ Questions with Answers PDF Free Download as per Mechanical Engineering new exam pattern? You came to the right page. This may assist you to understand and check your knowledge about the Subjects. Students also can take a free test of the Multiple Choice Questions of Mechanical Engineering. Each question has four options followed by the right answer. These Mechanical Engineering MCQ Questions are selected supported by the newest exam pattern.


Q1. In a typical medium speed 4-stroke cycle diesel engine the inlet valve

(A) Opens at 20° before top dead center and closes at 35° after the bottom dead center
(B) Opens at top dead center and closes at bottom dead center
(C) Opens at 10° after top dead center and closes 20° before the bottom dead center
(D) May open or close anywhere

Answer: (A) Opens at 20° before top dead center and closes at 35° after the bottom dead center


Q2. If the temperature of intake air in internal combustion engine increases, then its efficiency will

(A) Remain same
(B) Decrease
(C) Increase
(D) None of these

Answer: (B) Decrease


Q3. Crankcase explosion in I.C. engines usually occurs as

(A) First a mild explosion followed by a bi explosion
(B) First a big explosion followed by a mil explosion
(C) Both mild and big explosions occurs simultaneously
(D) Never occurs

Answer: (A) First a mild explosion followed by a bi explosion


Q4. Flash point of fuel oil is

(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) Temperature at which it catches fire without external aid
(D) Indicated by 90% distillation temperature, i.e. when 90% of sample oil has distilled off

Answer: (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


Q5. The compression ignition engines are governed by

(A) Hit and miss governing
(B) Qualitative governing
(C) Quantitative governing
(D) Combination of (B) and (C)

Answer: (B) Qualitative governing


Q6. When crude oil is heated, then which of the following hydrocarbon is given off first?

(A) Kerosene
(B) Gasoline
(C) Paraffin
(D) Natural gas

Answer: (D) Natural gas


Q7. Which of the following fuel detonates readily?

(A) Benzene
(B) Iso-octane
(C) Normal heptane
(D) Alcohol

Answer: (C) Normal heptane


Q8. The specific fuel consumption per BHP hour for diesel engine is approximately

(A) 0.15 kg
(B) 0.2 kg
(C) 0.25 kg
(D) 0.3 kg

Answer: (B) 0.2 kg


Q9. The ratio of the work obtained at the crankshaft in a given time to the energy supplied during the same time is called

(A) Mechanical efficiency
(B) Overall efficiency
(C) Indicated thermal efficiency
(D) Volumetric efficiency

Answer: (B) Overall efficiency


Q10. Air fuel ratio at which a petrol engine cannot work is

(A) 8 : 1
(B) 10 : 1
(C) 15 : 1
(D) 20 : 1 and less

Answer: (D) 20 : 1 and less


Q11. The reflectivity depends upon

(A) Geometry of the reflector
(B) Energy of neutrons
(C) Properties of the reflector
(D) All of these

Answer: (D) All of these


Q12. A 75 cc engine has following parameter as 75 cc

(A) Fuel tank capacity
(B) Lube oil capacity
(C) Swept volume
(D) Cylinder volume

Answer: (C) Swept volume


Q13. 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

Answer: (B) Below


Q14. The air-fuel ratio of the petrol engine is controlled by

(A) Fuel pump
(B) Governor
(C) Injector
(D) Carburettor

Answer: (D) Carburettor


Q15. The ratio of the brake power to the indicated power is called

(A) Mechanical efficiency
(B) Overall efficiency
(C) Indicated thermal efficiency
(D) Volumetric efficiency

Answer: (A) Mechanical efficiency


Q16. A spark plug gap is kept from

(A) 0.3 to 0.7 mm
(B) 0.2 to 0.8 mm
(C) 0.4 to 0.9 mm
(D) 0.6 to 1.0 mm

Answer: (A) 0.3 to 0.7 mm


Q17. The brake power is the power available

(A) In the engine cylinder
(B) At the crank shaft
(C) At the crank pin
(D) None of these

Answer: (B) At the crank shaft


Q18. The operation of forcing additional air under pressure into the engine cylinder is known as

(A) Supercharging
(B) Carburetion
(C) Turbulence
(D) Delay period

Answer: (A) Supercharging


Q19. The operation of forcing additional air under pressure in the engine cylinder is known as

(A) Scavenging
(B) Turbulence
(C) Supercharging
(D) Pre-ignition

Answer: (C) Supercharging


Q20. The air requirement of a petrol engine during starting compared to theoretical air required for complete combustion is

(A) More
(B) Less
(C) Same
(D) May be more or less depending on engine capacity

Answer: (B) Less


We hope the given Mechanical Engineering MCQ Questions with Answers will definitely yield fruitful results. Hope you got enough ideas on the MCQs on Mechanical Engineering. If you have any queries related to Mechanical Engineering MCQs Multiple Choice Questions with Answers, drop your questions below and will get back to you in no time.