I.C. ENGINE MCQ 0-3

Q.1 The gap between two electrodes of spark plug is the order of ______ .

A. 0.5 to 0.7 mm

B. 0.3 to 0.5 mm

C. 0.3 to 0.7 mm

D. 1.5 to 1.8 mm

Ans-: C

Q.2 Ignition quality of the diesel oil is expressed by which number?

A.  Octane number 

B. Cetane number 

C. Oil number 

D. None of these 

Ans-: B

Q.3 Removing the brunt gases from the engine cylinder is known as ______.

A. Exhaust process

B. Compression process 

C. Scavenging process

D. Detonation 

Ans-: C

Q.4 The density of atmospheric air is _____ at high altitude. 

A. High

B. Minimum 

C. Maximum 

D. Low

Ans-: D

Q.5 The power available at the shaft known as ____.

A. Brake HP

B. Indicated HP

C. Total power 

D. Shaft power 

Ans -: A

Q.6 In which type of scavenging process,  the incoming air is directed upward,  pushing the exhaust gases before it ?

A. Cross scavenging 

B. Loop scavenging 

C. Uniflow scavenging 

D. None of these 

Ans -: A

Q.7 The incoming air enters at the lower end of the cylinder and leave at the top in ______ scavenging process .

A. Loop scavenging 

B. Uniflow scavenging 

C. Cross scavenging 

D. None of these 

Ans -: B

Q.8 Gaseous-fuel guarantees are based on ____.

A. Mean heat value of oil

B. Low heat value of oil

C. Calorific value of oil 

D. All of the above 

Ans -: B

Q.9  A 75 CC engine has following parameter as 75 CC .

A. Fuel tank capacity 

B. Swept volume 

C. Cylindrical volume

D. Carbon consumption 

Ans -: B

Q.10 In an engine, size of inlet valve is ____ than exhaust valve. 

A. More 

B. Same 

C. Less

D. Depends on capacity of engine 

Ans-: C

Q.11 In a cycle the spark lasts roughly for ___ second .

A. 0.001 

B. 0.0001

C. 0.02 

D. 0.002

Ans -: A

Q.12 which is the most volatile and lightest liquid fuel ?

A. Kerosene 

B. Petrol

C. Diesel 

D. Gasoline 

Ans -: D

Q.13 Which device is used to diminish noise of the intake or exhaust?

A. Muffler 

B. Noise reducer

C. Converter

D. None of these

Ans -: A

Q.14 what is the standard firing order for 4 cylinder petrol engine?

A. 1-3-4-2

B. 1-2-3-4

C. 1-4-3-2

D. 1-4-2-3

Ans -: A

Q.15 What device is used for obtaining required firing order in S.I. engine ?

A. Carburettor 

B. Distributor 

C. Fly wheel

D. Valves 

Ans -: B

SUPERCHARGING

Supercharging -: Supercharging is the process of increasing the mass of air or density of air fuel mixture to the engine cylinder by compressing intake air initially with a view to obtain high power. This is usually done with the help of a compressor or blower.

                          Supercharging is used in I.C. engine to increase the volumetric efficiency. It is most common used in petrol engine. During supercharging the pressure of inlet air is increased above the atmospheric pressure by the supercharger. It can push high volume of air than the volume of air intaked by naturally aspirated engine of same capacity. 

                      Naturally aspirated engine have volumetric efficiency below the 90% but the supercharged engine the volumetric efficiency is above the 100 %.

                           Due to availability of higher oxygen during the combustion of fuel which ensure the better combustion of fuel . The advantage of supercharging is better combustion of fuel into the camber of cylinder. Due to this total power produced by the engine is also increased. There are two units used for increasing volumetric efficiency of engine , supercharger and turbocharger. The main difference in supercharger and turbocharger is that , supercharger is commonly used in petrol engine and turbocharger is commonly used in diesel engine. Turbocharger get the power from the exhaust gases of the engine to run the compressor through the turbine. In petrol engine combustion pressure is low so the energy of exhaust gas is also low as compare to diesel engine. For this reason turbocharger is not used in the petrol engine. 

        Supercharging is used generally at high altitude,  where density of atmospheric air is low . 

Concept of supercharging -: