i c engines MCQs – Page 6

Practise focused i c engines questions with marked answers for exam preparation and subject revision.

i c engines Mcqs
101. In a cycle, the spark lasts roughly for ____________________?
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A. 0.01 sec

B. 0.0001 sec

C. 0.001 sec

D. 1 sec

E. 0.1 sec

102. In order to prevent formation of carbon on the injector, the temperature of nozzle tip should be__________________?
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A. between 250 300C

B. less than 100C

C. between 100-250C

D. between 400 500C

E. between 500 1000C

103. To reduce the possibility of knock in the C.I. engines, the first elements of fuel and air should have_______________?
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A. reactive mixture

B. high temperature

C. high density

D. short delay

E. all of the above
104. A fuel will detonate less if it has___________________?
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A. proper self ignition temperature

B. lower self ignition temperature

C. none of the above

D. higher self ignition temperature

E. self ingition temperature has nothing to do with detonation

106. Flash point of fuel oil is __________________?
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A. temperature at which it catches fire without external aid

B. temperature at which it solidifies or congeals

C. minimum temperature to which1 oil is heated in order to give off inflammable vapours in sufficient quantity to ignite momentarily when brought in contact with a flame

D. indicated by 90% distillation temperature, i.e. when 90% of sample oil has distilled off

E. none of the above

107. Scavenging air in diesel engine means___________________?
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A. burnt air containing products of combustion

B. air used for forcing burnt gases out of engines cylinder during the exhaust period

C. forced air for cooling cylinder

D. air fuel mixture

E. air used for combustion sent under pres-sure

108. Kerosene is distilled at________________?
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A. 350 450C

B. 30 65C

C. 220 350C

D. 450-550C

E. 65 220C

109. Fuel consumption with increase in back pressure will________________?
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A. depend on other factors

B. increase

C. decrease

D. remain unaffected

E. none of the above

111. The function of a distributor in an automobile is to__________________?
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A. regulate power

B. distribute charge, equally to all the cylinders

C. feed lub oil to all moving parts

D. inject fuel at appropriate time

E. time the spark
112. In open combustion chamber in diesel engines____________________?
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A. fuel is injected into an auxiliary chamber that is separated from the cylinder by an orifice or throat

B. the shape and layout of the piston crown, the inlet port, and the valve produce the turbulent effect on fuel mixture

C. fuel is injected at atmospheric pressure

D. there are no valves.

E. only a part of air charge is contained in an auxiliary chamber in which the fuel starts to burn with insufficient air which due to explosion tendency mixes thoroughly into main cylinder charge

113. It the temperature of intake air in IC engines is lowered, then its efficiency will_______________________?
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A. decrease upto certain limit and then in-crease

B. decrease

C. increase upto certain limit and then decrease

D. increase

E. remain same

114. According to Recardos theory, detonation occurs due to______________________?
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A. none of the above

B. instantaneous auto-ignition of last part of charge to be burnt

C. improper mixing of air and fuel

D. self ignition temperature has nothing to do with detonation

E. improper combustion

115. The essential equipment for producing high vlotage for sparking in petrol engines with battery is_______________?
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A. ignition coil, contact breaker and con-denser

B. ignition coil

C. ignition coil and distributor

D. ignition coil and contact breaker

E. ignition coil and condenser

116. Fuel consumption of diesef engines is not guaranteed at one quarter load because at such low loads________________?
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A. the engine is rarely operated

B. the friction is unpredictable

C. none of the above

D. the small difference in cooling water temperature or in internal friction has a disproportionate effect

E. the friction is high

118. An engine indicator is used to determine the following___________________?
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A. volume of cylinder

B. speed

C. BHP

D. temperature

E. m.e.p. and I.H.P.
119. A heat engine utilises the_________________?
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A. mean heat value of oil

B. calorific value of oil

C. low heat value of

D. high heat value of oil

E. all of the above

120. Ethyl fluid is used_______________________?
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A. as a defrosting agent

B. as a superior type of fluid compared to others

C. to increase the cetane rating of the fuel

D. to increase the octane rating of the fuel

E. to improve lubricating quality of fuel