I.C Engines Objective Questions with Answers – Set 07

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Q1. The maximum temperature in the I.C. engine cylinder is of the order of

(A) 500-1000°C
(B) 1000-1500°C
(C) 1500-2000°C
(D) 2000-2500°C

Answer: (D) 2000-2500°C


Q2. A stoichiometric air-fuel ratio is

(A) Chemically correct mixture
(B) Lean mixture
(C) Rich mixture for idling
(D) Rich mixture for over loads

Answer:(A) Chemically correct mixture


Q3. The object of providing masked inlet valve in the air passage of compression ignition engines is to

(A) Enhance flow rate
(B) Control air flow
(C) Induce primary swirl
(D) Induce secondary turbulence

Answer: (C) Induce primary swirl


Q4. The air standard efficiency of an Otto cycle compared to diesel cycle for the given compression ratio is

(A) Same
(B) Less
(C) More
(D) More or less depending on power rating

Answer:(C) More


Q5. Which of the following statement is correct regarding petrol engines?

(A) A fine fuel spray mixed with air is ignited by the heat of compression which is at a high pressure
(B) The fuel supplied to the engine cylinder is mixed with necessary amount of air and the mixture in ignited with the help of a spark plug
(C) The fuel is first evaporated after passing through a carburettor and is mixed with air before ignition
(D) All of the above

Answer: (B) The fuel supplied to the engine cylinder is mixed with necessary amount of air and the mixture in ignited with the help of a spark plug


Q6. Which of the following is false statement?
Excess quantities of sulphur in diesel fuel are Objectionable because it may cause the following

(A) Piston ring and cylinder wear
(B) Formation of hard coating on piston skirts
(C) Oil sludge in the engine crank case
(D) Detonation

Answer: (D) Detonation


Q7. Which of the following does not relate to a spark ignition engine?

(A) Ignition coil
(B) Spark plug
(C) Carburettor
(D) Fuel injector

Answer: (D) Fuel injector


Q8. For the same power developed in I.C. engines, the cheaper system is

(A) Naturally aspirated
(B) Supercharged
(C) Centrifugal pump
(D) Turbo charger

Answer: (B) Supercharged


Q9. In a four stroke cycle petrol engine, the inlet valve

(A) Opens at top dead center and closes at bottom dead center
(B) Opens at 20° before top dead center and closes at 40° after bottom dead center
(C) Opens at 20° after top dead center and closes at 20° before bottom dead center
(D) May open or close anywhere

Answer: (B) Opens at 20° before top dead center and closes at 40° after bottom dead center


Q10. Air fuel ratio for idling speed of a petrol engine is approximately

(A) 1 : 1
(B) 5 : 1
(C) 10 : 1
(D) 15 : 1

Answer: (C) 10 : 1


Q11. Solid fuel fabricated into various small shapes, which are assembled to form fuel elements, is in the form of

(A) Plates
(B) Pallets
(C) Pins
(D) All of these

Answer: (D) All of these


Q12. A diesel engine as compared to petrol engine (both running and rated load) is

(A) More efficient
(B) Less efficient
(C) Equally efficient
(D) Other factors will decide it

Answer: (A) More efficient


Q13. A diesel engine has

(A) One valve
(B) Two valves
(C) Three valves
(D) Four valves

Answer: (C) Three valves


Q14. The injector nozzle of a compression ignition engine is required to inject fuel at a sufficiently high pressure in order to

(A) Inject fuel in a chamber of high pressure at the end of compression stroke
(B) Inject fuel at a high velocity to facilitate atomization
(C) Ensure that penetration is not high
(D) All of the above

Answer: (D) All of the above


Q15. If petrol is used in a diesel engine, then

(A) Low power will be produced
(B) Efficiency will be low
(C) Higher knocking will occur
(D) Black smoke will be produced

Answer: (C) Higher knocking will occur


Q16. The object of supercharging the engine is

(A) To reduce mass of the engine per brake power
(B) To reduce space occupied by the engine
(C) To increase the power output of an engine when greater power is required
(D) All of the above

Answer:(D) All of the above


Q17. In the opposed piston diesel engine, the combustion chamber is located

(A) Above the piston
(B) Below the piston
(C) Between the pistons
(D) There is no such criterion

Answer: (C) Between the pistons


Q18. 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 above

Answer: (B) Rotary motion of the gases in the chamber


Q19. The firing order in an I.C. engine depends upon

(A) Arrangement of the cylinders
(B) Design of crankshaft
(C) Number of cylinders
(D) All of these

Answer:(D) All of these


Q20. In the crankcase method of scavenging, the air pressure is produced by

(A) Supercharger
(B) Centrifugal pump
(C) Natural aspirator
(D) Movement of engine piston

Answer: (D) Movement of engine piston


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