Description : Scavenging air in diesel engine means a. air used for combustion under pressure b. forced air for cooling the cylinder c. burnt air containing products of combustion d. air used for forcing burnt gases out of the engines cylinder during the exhaust stroke
Last Answer : ANSWER d. air used for forcing burnt gases out of the engines cylinder during the exhaust stroke
Description : The tendency of a petrol engine to knock increases by a. supercharging b. scavenging c. increasing the engine horse power d. reducing the spark advance
Last Answer : ANSWER a. supercharging
Description : If one cylinder of a diesel engine receives more fuel than others , then for that cylinder the A. exhaust will be smoky B. scavenging occurs C. exhaust temperature will be high D. engine starts overheating
Last Answer : ANSWER : B
Description : Scavenging is usually done to increase the a. thermal efficiency b. speed c. power output d. fuel consumption
Last Answer : ANSWER c. power output
Description : The output of a diesel engine can be increased without increasing the engine size in following way a. injecting more fuel b. increasing flywheel size c. scavenging d. supercharging
Last Answer : ANSWER d. supercharging
Description : The process of breaking up a liquid into fine droplets by spraying is called a. vaporization b. carburetion c. injection d. atomization
Last Answer : ANSWER d. atomization
Description : Air fuel ratio at which a petrol engine cannot work is A. 8:1 B. 12:1 C. 15:1 D. 20:1 and less
Last Answer : ANSWER : D
Description : Air fuel ratio for idling speed of a petrol engine is approximately A. 1:1 B. 5:1 C. 20:1 D. 10:1
Description : The theoretically correct air fuel ratio of a petrol engine is of the order of A. 6:1 B. 10:1 C. 15:1 D. 20:1
Last Answer : ANSWER : C
Description : The fuel air ratio in a petrol engine fitted with suction carburetor, operating with dirty air filter as compared to clean filter will be A. higher B. lower C. remain unaffected D. unpredictable
Last Answer : ANSWER : A
Description : The air-fuel ratio of the petrol engine is governed by A. fuel pump B. governor C. carburetor D. injector
Description : The stoichiometric air fuel ration for petrol is 15:1 . What is the air fuel ratio required for maximum power? (a) 16:1 – 18:1 (b) 15:1 (c) 12:1 – 14:1 (d) 9:1 – 11:1
Last Answer : Ans :c
Description : Air fuel ratio at which a petrol engine cannot work is a. 8:1 b. 10:1 c. 20:1 and less d. 15:1
Last Answer : ANSWER c. 20:1 and less
Description : The theoretically correct air fuel ratio for petrol engine is of the order of a.6 : 1 b. 9 : 1 c. 12 : 1 d. 15 : 1
Last Answer : Answer d. 15:1
Description : Supercharging is essential in A. aircraft engines B. petrol engines C. gas turbines D. diesel engines
Description : Octane number of petrol normally used in petrol engines is of the order of a. 20-30 b. 40-60 c. 60-70 d. 80-90
Last Answer : ANSWER d. 80-90
Description : The term scavenging is generally associated with a. 2-stroke engine b. 4-stroke engine c. high efficiency engine d. diesel engine
Last Answer : ANSWER C. high efficiency engine
Description : The knocking tendency in CI engines increases with (a) Increase of coolant water temperature (b) Increase of temperature of inlet air (c) Decrease of compression ratio (d) Increase of compression ratio
Description : In SI engines knocking can be reduced by (a) Increasing the compression ratio (b) Increasing the cooling water temperature (c) Retarding the spark advance (d) Increasing the inlet air temperature
Description : In a refrigeration cycle, the flow of refrigerant is controlled by (a) compressor (b) condenser (c) evaporator (d) expansion valve
Last Answer : Ans: d
Description : Rate of burning in the compression ignition engine can be controlled by a. rate of injection of fuel b. rate of air taken into carburetor c. both a. and b. d. none of the above
Last Answer : ANSWER a. rate of injection of fuel
Description : Motoring test is conducted on IC engines to determine A. brake power B. indicated power C. friction power D. fuel consumption at full load
Description : For C.I. engines fuel most preferred are a) aromatics b) paraffins c) olefins d) napthenes
Last Answer : Answer: b Explanation: For C.I. engines fuel most preferred are paraffins and for S.I. engines fuel most preferred are aromatics.
Description : For S.I. engines fuel most preferred are a) aromatics b) paraffins c) olefins d) napthenes
Last Answer : Answer: a Explanation: For S.I. engines fuel most preferred are aromatics while for C.I. engines fuel most preferred are paraffins.
Description : Which of the following statement is not correct with respect to alcohols as alternate fuel in IC engines a) anti-knock characteristics of alcohol is poor b) alcohol contains about half the heat ... /litre c) alcohol does not vaporize as easily as gasoline d) alcohols are corrosive in nature
Last Answer : Answer: a Explanation: Anti-knock characteristics of alcohol is good.
Description : For same power output and same r, as compared to 2- stroke engines, four stroke SI engines have (a) Higher fuel consumption (b) Lower thermal efficiency (c) Highest exhaust temperatures (d) Higher thermal efficiency
Last Answer : Ans :d
Description : All heat engines utilize a. lower heating value of oil b. higher heating value of oil c. net calorific value of oil d. calorific value of fuel
Last Answer : ANSWER a. lower heating value of oil
Description : The specific fuel consumption of a petrol engine compared to diesel engine of same H.P is A. same B.more C. less D. unpredictable
Description : A fuel of cetane number 40 has the same ignition quality as a mixture of a) 40% cetane and 60% alpha methyl naphthalene b) 40% alpha methyl naphthalene and 60% cetane c) 40% petrol and 60% diesel d) 40% diesel and 60% petrol
Last Answer : Answer: a Explanation: A fuel of cetane number 40 has the same ignition quality as a mixture of 40% cetane and 60% alpha methyl naphthalene as cetane number is counted on cetane percentage.
Description : A fuel of an octane number rating of 75 matches in knocking intensity as a mixture of a) 75% iso-octane and 25% normal heptane b) 75% normal heptane and 25% iso-octane c) 75% petrol and 25% diesel d) 75% diesel and 25% petrol
Last Answer : Answer: a Explanation: None.
Description : The self-ignition temperature of diesel oil compared to petrol is a. higher b. lower c. same d. depends on the quality of fuel
Last Answer : ANSWER a. higher
Description : The specific fuel consumption per BHP hour for petrol engine is approximately a. 0.1 kg b. 0.2 kg c. 0.25 kg d. 0.35 kg
Last Answer : ANSWER c. 0.25 kg
Description : In spark ignition engines, the knocking tendency can be decreased by a) decreasing compression ratio b) controlling intake throttle c) controlling ignition timing d) adding dopes like tetraethyl lead and ethylene dibromide
Last Answer : Answer: d Explanation: None.
Description : Which of the following factors increases the tendency of knocking in the CI engines? (a) Increasing both the r and coolant temperatures (b) Increasing both the speed and the injection advance (c) Increasing the speed, injection advance and coolant temperature (d) Increasing the compression ratio
Description : For the same capacity engines, the compression ratio of diesel engine a. is lower than the compression ratio of SI engine b. is higher than the compression ratio of SI engine c. is same as the compression ratio of SI engine d. cannot say
Last Answer : ANSWER b. is higher than the compression ratio of SI engine
Description : In a simple carburetor, the air-fuel ratio increases when the A. density of air increases B. velocity of air increases C. velocity of air decreases D. density of air decreases
Description : In _____________ sensor, output voltage changes in proportion to air-fuel ratio. a) engine temperature b) exhaust gas c) air flow d) air inlet temperature
Last Answer : Answer: b Explanation: Only in exhaust gas sensor, output voltage changes in proportion to air-fuel ratio.
Description : _____________ senor senses the amount of oxygen in the engine exhaust and calculates air-fuel ratio. a) Engine temperature b) Exhaust gas c) Air flow d) Air inlet temperature
Last Answer : Answer: b Explanation: Exhaust gas senor senses the amount of oxygen in the engine exhaust and calculates airfuel ratio while engine temperature sensor senses the temperature of the engine coolant, and from this data the computer adjusts the mixture strength to rich side for cold starting.
Description : If the performance of diesel engine of different sizes, cylinder dimensions and power rating are to be compared, which of the following parameters can be used for such comparison? (a) Swept volume (b) Air fuel ratio (c) Specific brake fuel consumption (d) Volumetric efficiency
Description : Which of the following is normally not found in both the S.I. (petrol) & C.I. (diesel) engines? (A) Air filter (B) Fuel injector (C) Exhaust silencer (D) Battery
Last Answer : Option B
Description : The air requirement of a petrol engine during starting compared to the theoretical air requirement for complete combustion is A. more B.unpredictable C. same D. less
Description : 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
Last Answer : ANSWER b. less
Description : Detonation can be controlled by a. varying the compression ratio b. using lean mixture c. retarding the spark timing d. reducing the rpm
Last Answer : ANSWER c. retarding the spark timing
Description : Morse test is conducted on the engine to calculate the mechanical efficiency of A. single cylinder CI engine B. single cylinder SI engine C. only on two stroke engines D. multi cylinder engine
Description : Alcohols alone cannot be used in CI engines as a) their self ignition temperature is high b) latent heat of vaporization is high c) all of the mentioned d) none of the mentioned
Last Answer : Answer: c Explanation: None.
Description : With EFI of diesel engines a) sharp start and stop is not possible b) very high injection pressure can be obtained c) sudden cylinder cut-off is impossible d) diagnostic properties are poor
Last Answer : Answer: b Explanation: Generally, with EFI of diesel engines very high injection pressure can be obtained.
Description : Anti-knock for compression ignition engines is a) napthene b) tetra ethyl lead c) amyl nitrate d) hexadecane
Last Answer : Answer: c Explanation: Amyl nitrate is the anti-knock for compression ignition engines.
Description : Which one of the following types of compressor is mostly used for supercharging of IC engines? (a) Radial flow compressor (b) Axial flow compressor (c) Root blower (d) Reciprocating compressor
Last Answer : Ans : c
Description : The knocking in spark ignition engines can be reduced by a. Retarding the spark. b. Increasing the engine speed. c. Both a and b d. None of these.
Last Answer : ANSWER c. Both a and b.
Description : In compression ignition engines, swirl denotes a. Haphazard motion of the gases in the cylinder b. Rotary motion of the gases in the cylinder. c. Radial motion of the gases in the cylinder. d. None of the above
Last Answer : ANSWER a. Haphazard motion of the gases in the chamber