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Free download in PDF IC Engines Short Questions & Answers for competitive exams. These short objective type questions with answers are very important for Board exams as well as competitive exams. These short solved questions or quizzes are provided by Gkseries.
41
The air requirement of a petrol engine during starting compared to theoretical airequired for complete combustion is___________________?
A
more
B
loss
C
same
D
may be more or less depending on engine capacity
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42
The specific fuel consumption per BHP hour for diesel engine is approximately___________________?
A
0.15 kg
B
0.2 kg
C
0.25 kg
D
0.3 kg
View Answer
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43
Compression loss in I.C engines occurs due to_________________?
A
leaking piston rings
B
use of thick head gasket
C
clogged air-inlet slots
D
all of the above
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44
The temperature of interior surface of cylinder wall in normal operation is not allowed to exceed____________________?
A
80°C
B
120°C
C
180°C
D
240°C
View Answer
45
Combustion in compression ignition engines is____________________?
A
homogeneous
B
heterogeneous
C
both A. and B.
D
laminar
View Answer
46
The thermal efficiecny of a diesel cycle having fixed compression ratio, with increase in cut-off ratio will___________________?
A
increase
B
decrease
C
be independent
D
may increase or decrease depending on other factors
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47
If the compression ratio of an engine working on Otto cycle is increased from 5 to 7, the %age increase in efficiency will be________________?
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48
The pressure at the end of compression in the case of diesel engine is of the order of___________________?
A
6 kg/cm
B
12kg/cmz
C
20 kg/cmz
D
35 kg/cm
View Answer
49
In a typical medium speed 4-stroke cycle diesel engine the inlet valve_____________________?
A
opens at 20° before top dead center and closes at 35° after the bottom dead center
B
opens at top dead center and closes at bottom dead center
C
opens at 10° after top dead center and closes 20° before the bottom dead center
D
may open or close anywhere
View Answer
Answer: opens at 20° before top dead center and closes at 35° after the bottom dead center
50
An engine indicator is used to determine the following___________________?
A
speed
B
temperature
C
volume of cylinder
D
m.e.p. and I.H.P.
View Answer
Answer: m.e.p. and I.H.P.
51
If the intake air temperature of I.C. engine increases, its efficiency will_________________?
A
increase
B
decrease
C
remain same
D
unpredictable
View Answer
52
The ratio of indicated thermal efficiency to the corresponding air standard cycle efficiency is called__________________?
A
net efficiency
B
efficiency ratio
C
relative efficiency
D
overall efficiency
View Answer
Answer: relative efficiency
53
In a diesel engine, the fuel is ignited by___________________?
A
spark
B
injected fuel
C
heat resulting from compressing air that is supplied for combustion
D
ignition
View Answer
Answer: heat resulting from compressing air that is supplied for combustion
54
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
View Answer
55
Does the supply of scavenging air at a density greater than that of atmosphere mean engine is supercharged ?
A
yes
B
no
C
to some extent
D
unpredictable
View Answer
56
Scavenging air in diesel engine means___________________?
A
air used for combustion sent under pres-sure
B
forced air for cooling cylinder
C
burnt air containing products of combustion
D
air used for forcing burnt gases out of engine’s cylinder during the exhaust period
View Answer
Answer: air used for forcing burnt gases out of engine’s cylinder during the exhaust period
57
The working cycle in case of four stroke engine is completed in following number of revolutions of crankshaft___________________?
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58
The knock in diesel engine occurs due to____________________?
A
instantaneous and rapid burning of the first part of the charge
B
instantaneous atuo iginition of last part of charge
C
delayed burning of the first part of the charge
D
reduction of delay period
View Answer
Answer: instantaneous and rapid burning of the first part of the charge
59
Diesel engine can work on very lean air fuel ratio of the order of 30 : 1. A petrol engine can also work on such a lean ratio provided__________________?
A
it is properly designed
B
best quality fuel is used
C
can not work as it is impossible
D
flywheel size is proper
View Answer
Answer: can not work as it is impossible
60
A diesel engine has_________________?
A
1 valve
B
2 valves
C
3 valves
D
4 valves
View Answer
