Iso-octane (C8H18) has octane number of
0
50
100
120
Correct Answer :
C. 100
Related Questions
The two reference fuels used for cetane rating are
Cetane and iso-octane
Cetane and alpha-methyl naphthalene
Cetane and normal heptane
Cetane and tetra ethyl lead
The basic requirement of a good combustion chamber is
Minimum turbulence
Low compression ratio
High thermal efficiency and power output
Low volumetric efficiency
In the opposed piston diesel engine, the combustion chamber is located
Above the piston
Below the piston
Between the pistons
There is no such criterion
The air-fuel ratio of the petrol engine is controlled by
Carburettor
Injector
Governor
None of these
The inlet valve of a four stroke cycle internal combustion engine remains open for
130°
180°
230°
270°
A diesel engine, during suction stroke, draws
Air only
Diesel only
A mixture of diesel and air
None of these
The thermal efficiency of diesel engines is about
15 %
30 %
50 %
70 %
The exhaust valve in a four stroke cycle petrol engine
Opens at 50° before bottom dead centre and closes at 15° after top dead centre
Opens at bottom dead centre and closes at top dead centre
Opens at 50° after bottom dead centre and closes at 15° before top dead centre
May open and close anywhere
An engine indicator is used to determine the following
Speed
Temperature
Volume of cylinder
m.e.p. and I.H.P.
Compression ratio of I.C. Engines is
The ratio of volumes of air in cylinder before compression stroke and after compression stroke
Volume displaced by piston per stroke and clearance volume in cylinder
Ratio of pressure after compression and before compression
Swept volume/cylinder volume
In a petrol engine, the mixture has the lowest pressure at the
Beginning of suction stroke
End of suction stroke
End of compression stroke
None of these
A 75 cc engine has following parameter as 75 cc
Fuel tank capacity
Lube oil capacity
Swept volume
Cylinder volume
The self ignition temperature of petrol is ________ as compared to diesel oil.
Same
Lower
Higher
None of these
A petrol engine, during suction stroke draws
Air only
Petrol only
A mixture of petrol and air
None of these
The accumulation of carbon in a cylinder results in increase of
Clearance volume
Volumetric efficiency
Ignition time
Effective compression ratio
Volatility of diesel fuel oil is
Minimum temperature to which oil is heated in order to give off inflammable vapours in sufficient quantity to ignite momentarily when brought in contact with a flame
Temperature at which it solidifies or congeals
It catches fire without external aid
Indicated by 90% distillation temperature, i.e., when 90% of sample oil has distilled off
Iso-octane (C8H18) has octane number of
0
50
100
120
The output of a diesel engine can be increased without increasing the engine revolution or size in following way
Feeding more fuel
Heating incoming air
Scavenging
Supercharging
Morse test is used to determine the I.P. of a
Single cylinder petrol engine
Four stroke engine
Single cylinder diesel engine
Multi cylinder engine
The normal heptane (C7H16) is given a rating of ________ octane number.
0
50
100
120
Engine pistons are usually made of aluminium alloy because it
Is lighter
Wear is less
Absorbs shocks
Is stronger
The injector nozzle of a compression ignition engine is required to inject fuel at a sufficiently high pressure in order to
Inject fuel in a chamber of high pressure at the end of compression stroke
Inject fuel at a high velocity to facilitate atomisation
Ensure that penetration is not high
All of the above
A fuel of cetane number 40 has the same ignition quality as a mixture of
40% cetane and 60% alpha methyl naphthalene
40% alpha methyl naphthalene and 60% cetane
40% petrol and 60% diesel
40% diesel and 60% petrol
The air requirement of a petrol engine during starting compared to theoretical air required for complete combustion is
More
Less
Same
May be more or less depending on engine capacity
Supercharging is essential in
Diesel engines
Gas turbines
Petrol engines
Aircraft engines
As compared to air standard cycle, in actual working, the effect of variation in specific heats is to
Increase maximum pressure and maximum temperature
Reduce maximum pressure and maximum temperature
Increase maximum pressure and decrease maximum temperature
Decrease maximum pressure and increase maximum temperature
The pressure inside the cylinder is _________ the atmospheric pressure during the exhaust stroke.
Equal to
Below
Above
None of these
Theoretically, a four stroke cycle engine should develop _________ power as that of a two stroke cycle engine.
Half
Same
Double
Four times
The air-fuel ratio of the petrol engine is controlled by
Fuel pump
Governor
Injector
Carburettor
Number of working strokes per min. for a two stroke cycle engine is _________ the speed of the engine in r.p.m.
Equal to
One-half
Twice
Four-times