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Home » Engineering » Mechanical Engineering » Aptitude Test - 11
1.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. plates
2.The turbine of the turbo-prop engine is __________ that of the turbo-jet engine.
A. same as
B. smaller than
C. bigger than
D. same as
3.A higher compression ratio causes
A. pre-ignition
B. increase in detonation
C. an acceleration in the rate of combustion
D. pre-ignition
4.Which of the following statement is correct ?
A. Compression ratio for petrol engines varies from 6 to 10.
B. Higher compression ratio in diesel engines results in higher pressures.
C. Petrol engines work on Otto cycle.
D. Compression ratio for petrol engines varies from 6 to 10.
5.The correct sequence of the decreasing order of brake thermal efficiency of the three given basic types of engines is
A. four stroke C.I. engine, four stroke S.I. engine, two stroke S.I. engine
B. four stroke S.I. engine, four stroke C.I. engine, two stroke S.I. engine
C. four stroke C.I. engine, two stroke S.I. engine, four stroke S.I. engine
D. four stroke C.I. engine, four stroke S.I. engine, two stroke S.I. engine
6.The combustion in compression ignition engines is
A. homogeneous
B. hetrogeneous
C. both (a) and (b)
D. homogeneous
7.Which of the following fuel detonates readily ?
A. Benzene
B. Iso-octane
C. Normal heptane
D. Benzene
8.Spark plugs in automobiles generally have a gap between
A. 0.3 to 0.7 mm
B. 0.2 to 0.8 mm
C. 0.4 to 0.9 mm
D. 0.3 to 0.7 mm
9.In a petrol engine, if diesel is used, then the engine will
A. not run
B. run more efficiently
C. run at high speed
D. not run
10.Number of working strokes per min. for a four stroke cycle engine are _____ the speed of the engine in r.p.m.
A. equal to
B. one-half
C. twice
D. equal to
11.The air standard efficiency of an I.C. engine depends on
A. fuel used
B. speed of engine
C. compression ratio
D. fuel used
12.The knocking tendency in spark ignition engines may be decreased by
A. controlling the air-fuel mixture
B. controlling the ignition timing
C. controlling the exhaust temperature
D. controlling the air-fuel mixture
13.Alpha-methyl-naphthalene (C11 H10) has a cetane number of
A. 0
B. 50
C. 100
D. 0
14.In a petrol engine, the mixture has the lowest pressure at the
A. beginning of suction stroke
B. end of suction stroke
C. end of compression stroke
D. beginning of suction stroke
15.Which of the following does not relate to a spark ignition engine ?
A. Ignition coil
B. Spar kplug
C. Carburettor
D. Ignition coil
16.The increase in intake temperature of internal combustion engines will ___ efficiency.
A. have no effect on
B. increase
C. decrease
D. have no effect on
17.The reflectivity depends upon
A. geometry of the reflector
B. energy of neutrons
C. properties of the reflector
D. geometry of the reflector
18.In order to prevent knocking in spark ignition engines, the charge away from the spark plug should have
A. low density
B. low temperature
C. long ignition delay
D. low density
19.A gas engine has a swept volume of 300 cm3 and clearance volume of 25 cm3. Its volumetric efficiency is 0.88 and mechanical efficiency is 0.90. The volume of the mixture taken in per stroke is
A. 248 cm3
B. 252 cm3
C. 264 cm3
D. 248 cm3
20.Iso-octane (C8H18) has octane number of
A. 0
B. 50
C. 100
D. 0
21.The operation of forcing additional air under pressure into the engine cylinder is known as
A. supercharging
B. carburation
C. turbulence
D. supercharging
22.The thermal efficiency of a petrol engine is __________ as compared to diesel engine.
A. same
B. less
C. more
D. same
23.The compression ignition engines are governed by
A. hit and miss governing
B. qualitative governing
C. quantitative governing
D. hit and miss governing
24.The specific fuel consumption per B.P. hour for a diesel engine is about
A. 0.2 kg
B. 0.25 kg
C. 0.3 kg
D. 0.2 kg
25.The ignition quality of diesel oil is expressed by
A. cetane number
B. octane number
C. calorific value
D. cetane number
26.In a four stroke cycle petrol engine, the expansion
A. starts at top dead centre and ends at bottom dead centre
B. starts at 30° before top dead centre and ends at 50° before bottom dead centre
C. starts at 30° after top dead centre and ends at 50° after bottom dead centre
D. starts at top dead centre and ends at bottom dead centre
27.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% iso-octane and 25% normal heptane
28.A two stroke cycle engine gives __________ the number of power strokes as compared to the four stroke cycle engine, at the same engine speed.
A. half
B. same
C. double
D. half
29.By higher octane number of spark ignition fuel, it is meant that the fuel has
A. higher heating value
B. higher flash point
C. lower volatility
D. higher heating value
30.The spark ignition engines are governed by
A. hit and miss governing
B. qualitative governing
C. quantitative governing
D. hit and miss governing
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