Advantage of reciprocating IC engines over steam turbine is
A.
Mechanical simplicity
B.
Improved plant efficiency
C.
Lower average temperature
D.
all of the above
Answer»
D. all of the above
2.
The intake charge in a diesel engine consists of
A.
air alone
B.
air + lubricating oil
C.
air + fuel
D.
air + fuel + lubricating oil
Answer»
A. air alone
3.
Engines of different cylinder dimensions, power and speed can be compared on the basis of
A.
Maximum pressure
B.
Fuel consumption
C.
mean effective pressure
D.
unit power
Answer»
C. mean effective pressure
4.
Disadvantages of reciprocating IC engine are
A.
vibration
B.
use of fossil fuels
C.
balancing problems
D.
all of the above
Answer»
D. all of the above
5.
Gudgeon pin forms the link between
A.
piston and big end of connecting rod
B.
piston and small end of connecting rod
C.
connecting rod and crank
D.
big end and small end
Answer»
B. piston and small end of connecting rod
6.
In a four-stroke IC engine cam shaft rotates at
A.
same speed as crankshaft
B.
twice the speed of crankshaft
C.
halt the speed of crankshaft
D.
none of the above
Answer»
C. halt the speed of crankshaft
7.
Thermal efficiency of CI engine is higher than that of SI engine due
A.
light weight
B.
higher compression ratio
C.
constant pressure heat addition
D.
none of the above
Answer»
B. higher compression ratio
8.
SI engines are of
A.
light weight
B.
high speed
C.
homogeneous change of fuel and oil
D.
all of the above
Answer»
D. all of the above
9.
Compression ratio in diesel engines is of the order of
A.
5-7
B.
7 -10
C.
10 – 12
D.
14-20
Answer»
D. 14-20
10.
Main advantage of a two-stroke engine over four-stroke engine is
A.
more uniform torque on the crankshaft
B.
more power output for the cylinder of same dimensions
C.
absence of valves
D.
all of the above
Answer»
D. all of the above
11.
Engines used for ships are normally
A.
four-stroke Sl engines of very high power
B.
two-stroke CI engines of very high power
C.
four-stroke Cl engines of high speed
D.
two-stroke SI engines of high power
Answer»
B. two-stroke CI engines of very high power
12.
If L is the stroke and N is the rpm, mean piston speed of two-stroke engine
A.
LN
B.
LN/2
C.
2LN
D.
none of the above
Answer»
C. 2LN
13.
The volumetric efficiency of the SI engine is comparatively
A.
lower than CI engine
B.
higher than CI engine
C.
will be same as CI engine
D.
none of the above
Answer»
A. lower than CI engine
14.
Brake specific fuel consumption is defined as
A.
fuel consumption per hour
B.
fuel consumption per km
C.
fuel consumption per BP
D.
fuel consumption per brake power hour
Answer»
D. fuel consumption per brake power hour
15.
Engine can be fired with
A.
solid fuel
B.
liquid fuel
C.
gaseous fuel
D.
any of the above fuels
Answer»
D. any of the above fuels
16.
A two-stroke engine can be identified by
A.
cooling system
B.
lubrication system
C.
absence of valves
D.
piston size
Answer»
C. absence of valves
17.
Advantage of two-stroke engine is
A.
more uniform torque
B.
lighter flywheel
C.
no valves
D.
all of the above
Answer»
D. all of the above
18.
Charge pressure at the inlet port of a two-stroke engine is
A.
20 bar
B.
vacuum
C.
atmospheric
D.
higher than atmospheric
Answer»
D. higher than atmospheric
19.
The most perfect method of scavenging is
A.
cross scavenging
B.
uniflow scavenging
C.
loop scavenging
D.
reverse flow scavenging
Answer»
B. uniflow scavenging
20.
Two-stroke SI engines suffer from
A.
fuel loss
B.
idling difficulty
C.
both (a) and (b) together
D.
none of the above
Answer»
A. fuel loss
21.
At the same speed two-stroke engine of the same size as a four-stroke engine will develop
A.
same power
B.
half the power
C.
twice the power
D.
four times the power
Answer»
C. twice the power
22.
Two wheelers without deflector type piston use
A.
loop scavenging
B.
unifow scavenging
C.
reverse flow scavenging
D.
cross scavenging
Answer»
D. cross scavenging
23.
Crankcase scavenged engines have delivery ratio of
A.
greater than 1
B.
less than 1
C.
equal to 1
D.
none of the above
Answer»
C. equal to 1
24.
The working cycle in case of four stroke engine is completed in following number of revolutions of crankshaft
A.
1/2
B.
1
C.
2
D.
4
Answer»
C. 2
25.
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.
ignitor
Answer»
C. heat resulting from compressing air that is supplied for combustion
26.
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 com-bastion
D.
air used for forcing burnt gases out of engine's cylinder during the exhaust period
Answer»
D. air used for forcing burnt gases out of engine's cylinder during the exhaust period
27.
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
Answer»
B. no
28.
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
Answer»
C. relative efficiency
29.
Compression ratio of LC. Engines is
A.
the ratio of volumes of air in cylinder before compression stroke and after compression stroke
B.
volume displaced by piston per stroke and clearance volume in cylinder
C.
ratio of pressure after compression and before compression
D.
swept volume/cylinder volume
Answer»
A. the ratio of volumes of air in cylinder before compression stroke and after compression stroke
Chapter: Fuel Air Cycles and Actual Cycles
30.
A perfect engine works on the Carnot cycle between 727 °C and 227°C. The efficiency of the engine is
A.
0.5
B.
0.75
C.
1
D.
0.25
Answer»
A. 0.5
31.
The air standard Otto cycle consists of
A.
two constant volume and two isentropic processes
B.
two constant pressure and two isentropic processes
C.
two constant pressure and two constant volume processes
D.
none of the above
Answer»
A. two constant volume and two isentropic processes
32.
In air standard Diesel cycle at fixed r and fixed n
A.
ƞthermal increases with increase in heat addition and cut-off ratio
B.
ƞthermal decreases with increase in heat addition and cut-off ratio
C.
ƞthermal Remains the same with increase in heat addition and cut-off ratio
D.
none of the above
Answer»
B. ƞthermal decreases with increase in heat addition and cut-off ratio
33.
Mean effective pressure of Otto cycle is
A.
inversely proportional to pressure ratio
B.
directly proportional to pressure ratio
C.
does not depend on pressure ratio
D.
proportional to square root of pressure ratio
Answer»
B. directly proportional to pressure ratio
34.
For a given compression ratio the work output of Otto cycle is
A.
increases with Increase in r
B.
decreases with increase in r
C.
is not affected
D.
none of the above
Answer»
A. increases with Increase in r
35.
For a given value of r, efficiency of Otto cycle
A.
decreases with compression ratio
B.
increases with compression ratio
C.
is not affected
D.
none of the above
Answer»
B. increases with compression ratio
36.
For dual combustion cycle for fixed value of heat addition and compression ratio
A.
mep wil be greater with increase in rp, and decrease in rc
B.
mep will be greater with decrease in rp and decrease in rc
C.
mep remain the same with increase in rp and decrease in rc
D.
none of the above
Answer»
A. mep wil be greater with increase in rp, and decrease in rc
37.
The normal range of, compression ratio for Otto cycle is
A.
6 to 10
B.
2 to 4
C.
>10
D.
none of the above
Answer»
A. 6 to 10
38.
The normal range of compression ratio for Diesel cycle is
A.
4 to 6
B.
6 to 8
C.
15 to 20
D.
>25
Answer»
C. 15 to 20
39.
For the same compression ratio and heat addition
A.
ƞOtto > ƞDiesel > ƞDual
B.
ƞDiesel > ƞOtto > ƞDual
C.
ƞOtto> ƞDual > ƞDiesel
D.
ƞDual> ƞDiesel > ƞOtto
Answer»
C. ƞOtto> ƞDual > ƞDiesel
40.
for the same compression ratio and heat rejection,
A.
ƞOtto> ƞDual > ƞDiesel
B.
ƞDiesel > ƞDual > ƞOtto
C.
ƞDual> ƞDiesel > ƞOtto
D.
ƞDual> ƞOtto> ƞDiesel
Answer»
A. ƞOtto> ƞDual > ƞDiesel
41.
When the engines are built to withstand the sane thermal and mechanical stresses
A.
ƞDiesel > ƞDual > ƞOtto
B.
ƞDual> ƞDiesel > ƞOtto
C.
ƞOtto> ƞDual > ƞDiesel
D.
ƞOtto> ƞDiesel > ƞDual
Answer»
A. ƞDiesel > ƞDual > ƞOtto
42.
For the same peak pressure and heat input
A.
ƞOtto > ƞDual > ƞDiesel
B.
ƞOtto > ƞDiesel > ƞDual
C.
ƞDiesel > ƞDual > ƞOtto
D.
ƞDiesel > ƞOtto > ƞDual
Answer»
C. ƞDiesel > ƞDual > ƞOtto
43.
For the same peak pressure and work output
A.
ƞOtto > ƞDual > ƞDiesel
B.
ƞOtto > ƞDiesel > ƞDual
C.
ƞDiesel > ƞOtto > ƞDual
D.
ƞDiesel > ƞDual > ƞOtto
Answer»
D. ƞDiesel > ƞDual > ƞOtto
44.
Brayton cycle is used in
A.
Ramjet engines
B.
gas turbines
C.
pulse jet engines
D.
Cl engines
Answer»
B. gas turbines
45.
The actual efficiency of a good engine is about _______of the estimated fuel-air cycle
efficiency.
A.
100%
B.
85%
C.
50%
D.
25%
Answer»
B. 85%
46.
With dissociation peak temperature is obtained
A.
at the stoichiometric air-fuel ratio
B.
when the mixture is slightly lean
C.
when the mixture is slightly rich
D.
none of the above
Answer»
C. when the mixture is slightly rich
47.
With dissociation the exhaust gas temperature
A.
decreases
B.
increases
C.
no effect
D.
increases upto certain air-fuel ratio and then decreases
Answer»
A. decreases
48.
Fuel-air ratio affects maximum power output of the engine due to
A.
higher specific heats
B.
chemical equilibrium losses
C.
both (a) and (b)
D.
none of the above
Answer»
C. both (a) and (b)
49.
Mean effective pressure at a given compression ratio is maximum when the air-fuel ratio is
A.
higher than stoichiometric
B.
lower than stoichiometric
C.
equal to stoichionetric
D.
none of the above
Answer»
B. lower than stoichiometric
50.
For a compressor process with variable specific heat the peak temperature and pressure are
_______compared to constant specific heat
A.
lower
B.
higher
C.
no effect
D.
none of the above
Answer»
A. lower
51.
Dissociation can be considered as
A.
disintegration of combustion products at high temperature
B.
reverse process of combustion
C.
heat absorption process
D.
all of the above
Answer»
D. all of the above
52.
Time loss factor in actual cycle is due to
A.
Progressive combustion
B.
heat loss through cylinder walls
C.
gas leakage
D.
friction
Answer»
A. Progressive combustion
53.
The major loss in a SI engine is due to
A.
exhaust blow down
B.
pumping
C.
incomplete combustion
D.
variation in specific heat and chemical equilibrium
Answer»
D. variation in specific heat and chemical equilibrium
54.
Fuel-air cycle efficiency is less than air-standard cycle efficiency by an amount equal to
A.
pumping loss
B.
friction loss
C.
loss due to specific heat variation and chemical equilibrium
D.
exhaust blow down loss
Answer»
C. loss due to specific heat variation and chemical equilibrium
55.
The major loss in a CI engine is
A.
direct heat loss
B.
loss due to incomplete combustion
C.
rubbing friction loss
D.
pumping loss
Answer»
B. loss due to incomplete combustion
56.
The ratio of the actual efficiency and the fuel-air cycle efficiency for CI engines is about
A.
0.2-0.3
B.
0.5-0.6
C.
1.0
D.
0.6-0.8
Answer»
D. 0.6-0.8
57.
In an actual SI engine the pumping loss with respect to speed
A.
decreases
B.
Increases
C.
remains constant
D.
nothing to do with speed
Answer»
B. Increases
58.
The volumetric efficiency is affected by
A.
the exhaust gas in the clearance volume
B.
the design of intake and exhaust valve
C.
valve timing
D.
all of the above
Answer»
D. all of the above
59.
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
60.
In a typical medium speed, 4-stroke cycle diesel engine
A.
fuel injection starts at 10° before to dead center and ends at 20° after tor dead center
B.
fuel injection starts at top dead center and ends at 20° after top dead center
C.
fuel injection starts at just before top dead center and ends just after top dead center
D.
may start and end anywhere
Answer»
A. fuel injection starts at 10° before to dead center and ends at 20° after tor dead center
Chapter: Combustion
61.
The amount of heat liberated by complete combustion of unit quantity of fuel is known as
________
A.
Agitation
B.
Combustion
C.
Calorific value
D.
Thermogenesis
Answer»
C. Calorific value
62.
The calorific value of gaseous fuels is expressed in terms of
A.
kcal
B.
B. kcal/kg
C.
C. kcal/m²
D.
D. kcal/m3
Answer»
D. D. kcal/m3
63.
What is the significance of calorific value?
A.
Helps in deciding which fuel is good
B.
Helps in locating fuel
C.
Helps in deciding ignition temperature
D.
Helps in deciding fire point
Answer»
A. Helps in deciding which fuel is good
64.
Which gas has the highest calorific value among given option?
A.
Oxygen
B.
Helium
C.
Hydrogen
D.
Nitrogen
Answer»
C. Hydrogen
65.
Which calorimeter is used to find calorific values of solid and liquid fuels?
A.
Boy’s calorimeter
B.
Bomb calorimeter
C.
Junker’s calorimeter
D.
Calvet-type calorimeter
Answer»
B. Bomb calorimeter
66.
Which calorimeter is used to find calorific values of gaseous fuels?
A.
Bomb calorimeter
B.
Junker calorimeter
C.
Adiabatic calorimeter
D.
Isothermal titration calorimeter
Answer»
B. Junker calorimeter
67.
What is the factor on which, difference between the two heating values of fuel depends on?
A.
Physical properties
B.
Reactants
C.
Chemical composition
D.
Products
Answer»
C. Chemical composition
68.
The Bomb calorimeter is used to determine the calorific value of:
A.
solids and liquid fuels
B.
solid and gaseous fuels
C.
liquid fuels that can be easily vaporized
D.
solid fuels only
Answer»
A. solids and liquid fuels
69.
If the intake air temperature of I.C. engine increases, its efficiency will
A.
increase
B.
decrease
C.
remain same
D.
unpredictable
Answer»
B. decrease
70.
All heat engines utilize
A.
low heat value of oil
B.
high heat value of oil
C.
net claorific value of oil
D.
calorific value of fuel
Answer»
A. low heat value of oil
71.
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.
Answer»
D. m.e.p. and I.H.P.
72.
Fuel oil consumption guarantees for I .C. engine are usually based on
A.
low heat value of oil
B.
high heat value of oil
C.
net calorific value of oil
D.
calorific value of fuel
Answer»
B. high heat value of oil
73.
Combustion in compression ignition engines is
A.
homogeneous
B.
heterogeneous
C.
both (a) and (b)
D.
laminar
Answer»
B. heterogeneous
74.
The air requirement of a petrol engine during starting compared to theoretical required for
complete combustion is
A.
more
B.
loss
C.
same
D.
may be more or less depending on engine capacity
Answer»
B. loss
75.
Diesel fuel, compared to petrol is
A.
less difficult to ignite
B.
just about the same difficult to ignite
C.
more difficult to ignite
D.
highly ignitable
Answer»
C. more difficult to ignite
76.
When crude oil is heated, then which of the following hydrocarbon is given off first.
A.
kerosene
B.
gasoline
C.
paraffin
D.
natural gas.
Answer»
D. natural gas.
77.
The rating of a diesel engine, with increase in air-intlet temperature, will
A.
increase linearly
B.
decrease linearly
C.
increase parabolically
D.
decrease parabolically
Answer»
B. decrease linearly
78.
A 75 cc engine has following parameter as 75 cc
A.
fuel tank capacity
B.
lub oil capacity
C.
swept volume
D.
cylinder volume
Answer»
C. swept volume
79.
A heat engine utilises the
A.
calorific value of oil
B.
low heat value of
C.
high heat value of oil
D.
mean heat value of oil
Answer»
C. high heat value of oil
80.
Gaseous-fuel guarantees are based on
A.
calorific value of oil
B.
low heat value of oil
C.
high heat value of oil
D.
mean heat value of oil
Answer»
B. low heat value of oil
81.
Fuel consumption of diesel engines is not guaranteed at one quarter load because at such
low loads
A.
the friction is high
B.
the friction is unpredictable
C.
the small difference in cooling water temperature or in internal friction has a disproportionate effect
D.
the engine is rarely operated
Answer»
C. the small difference in cooling water temperature or in internal friction has a disproportionate effect
82.
Polymerisation is a chemical process in which molecules of a compound become
A.
larger
B.
slowed down
C.
smaller
D.
liquid
Answer»
A. larger
83.
Which of the following is the lightest and most volatile liquid fuel
A.
diesel
B.
kerosene
C.
fuel oil
D.
gasoline
Answer»
D. gasoline
84.
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
Answer»
D. 15 : 1
85.
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
86.
Air fuel ratio at which a petrol engine can not work is
A.
8 : 1
B.
10 : 1
C.
15 : 1
D.
20 : 1 and less
Answer»
D. 20 : 1 and less
Chapter: Fuels and its Supply System SI and CI engine
87.
Advantage of gaseous fuel is that
A.
it can be stored easily
B.
it can mix easily with air
C.
it can displace more air from the engine
D.
all of the above
Answer»
B. it can mix easily with air
88.
Paraffins are in general represented by
A.
CnHn
B.
CnH2n
C.
CnH2n+2
D.
CnH2n-6
Answer»
C. CnH2n+2
89.
Paraffins have molecular structure of
A.
chain saturated
B.
chain unsaturated
C.
ring saturated
D.
ring unsaturated
Answer»
A. chain saturated
90.
Olefins are represented by the formula
A.
CnH2n
B.
CnH2n+2
C.
CnH2n-4
D.
CnH2n-6
Answer»
A. CnH2n
91.
Hydrocarbons are decomposed into smaller hydrocarbons by
A.
reforming
B.
refining
C.
cracking
D.
polymerization
Answer»
C. cracking
92.
The molecular structure of the straight-run gasoline is changed by
A.
cracking
B.
reforming
C.
reining
D.
boiling
Answer»
B. reforming
93.
For SI engines fuels most preferred are
A.
aromatics
B.
parafins
C.
olefins
D.
napthenes
Answer»
A. aromatics
94.
For CI engine fuels most preferred are
A.
napthenes
B.
paraffins
C.
olefins
D.
aromatics
Answer»
B. paraffins
95.
Octane number of iso-octane is
A.
0
B.
30
C.
60
D.
100
Answer»
D. 100
96.
Ignition quality of diesel fuel is indicated by its
A.
octane number
B.
cetane number
C.
fash point
D.
fire point
Answer»
B. cetane number
97.
Flash point of fuel oil is
A.
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
B.
temperature at which it solidifies or congeals
C.
temperature at which it catches fire without external aid
D.
indicated by 90% distillation temperature, i.e. when 90% of sample oil has distilled off
Answer»
A. 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
98.
Gasohol is a mixture of
A.
90% ethanol + 10% gasoline
B.
10% ethanol +90% gasoline
C.
40% ethanol + 60% gasoline
D.
50% ethanol +50% gasoline
Answer»
B. 10% ethanol +90% gasoline
99.
Stoichiometric air-fuel ratio of petrol is roughly
