The normal heptane (C7H16) is given a rating of ________ octane number.
0
50
100
120
Correct Answer :
A. 0
Related Questions
The rating of a diesel engine, with increase in air inlet temperature, will
Increase linearly
Decrease linearly
Increase parabolically
Decrease parabolically
The minimum cranking speed in case of petrol engine is about
Half the operating speed
One fourth of operating speed
250 - 300 rpm
60 - 80 rpm
Which one of the following event would reduce volumetric efficiency of a vertical compression ignition engine?
Inlet valve closing after bottom dead centre
Inlet valve closing before bottom dead centre
Inlet valve opening before top dead centre
Exhaust valve closing after top dead centre
Theoretically, a four stroke cycle engine should develop _________ power as that of a two stroke cycle engine.
Half
Same
Double
Four times
The reference fuels for knock rating of spark ignition engines would include
Iso-octane and alpha-methyl naphthalene
Normal octane and aniline
Isooctane and normal hexane
Normal heptane and isooctane
The turbine of the turboprop engine is __________ that of the turbojet engine.
Same as
Smaller than
Bigger than
None of these
Fuel consumption of diesel engines is not guaranteed at one quarter load because at such low loads
The friction is high
The friction is unpredictable
The small difference in cooling water temperature or in internal friction has a disproportionate effect
The engine is rarely operated
Morse test can be conducted for
Petrol engines
Diesel engines
Multi cylinder engines
All of these
The increase of efficiency of a compression ignition engine, as the load decreases, is due to
Higher maximum temperature
Qualitative governing
Quantitative governing
Hit and miss governing
A diesel engine has
One valve
Two valves
Three valves
Four valves
The ratio of the volume of charge admitted at N.T.P. to the swept volume of the piston is called
Mechanical efficiency
Overall efficiency
Volumetric efficiency
Relative efficiency
The air-fuel ratio of the petrol engine is controlled by
Fuel pump
Governor
Injector
Carburettor
Does the supply of scavenging air at a density greater than that of atmosphere mean engine is supercharged?
Yes
No
To some extent
Unpredictable
The compression ignition engines are governed by
Hit and miss governing
Qualitative governing
Quantitative governing
Combination of (B) and (C)
The inlet valve of a four stroke cycle internal combustion engine remains open for
130°
180°
230°
270°
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 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
The specific fuel consumption per B.P. hour for a petrol engine is about
0.2 kg
0.25 kg
0.3 kg
0.35 kg
The pressure at the end of compression in the case of diesel engine is of the order of
6 kg/cm
12 kg/cm
20 kg/cm
35 kg/cm
The compensating jet in a carburettor supplies almost constant amount of petrol at all speeds because the
Jet area is automatically varied depending on the suction
The flow from the main jet is diverted to the compensating jet with increase in speed
The diameter of the jet is constant and the discharge coefficient is invariant
Flow is produced due to the static head in the float chamber
The injection pressure in a diesel engine is about
10 bar
100 bar
150 bar
500 bar
A fuel of an octane number rating of 75 matches in knocking intensity as a mixture of
75% iso-octane and 25% normal heptane
75% normal heptane and 25% iso-octane
75% petrol and 25% diesel
75% diesel and 25% petrol
Which of the following is false statement? Excess quantities of sulphur in diesel fuel are Objectionable because it may cause the following
Piston ring and cylinder wear
Formation of hard coating on piston skirts
Oil sludge in the engine crank case
Detonation
The knocking tendency in spark ignition engines may be decreased by
Controlling the air-fuel mixture
Controlling the ignition timing
Controlling the exhaust temperature
Reducing the compression ratio
In an internal combustion engine, the process of removing the burnt gases from the combustion chamber of the engine cylinder is known as
Scavenging
Detonation
Supercharging
Polymerisation
The frictional power (F.P.) is given by
F.P. = B.P. - I.P.
F.P. = I.P. - B.P.
F.P. = B.P./I.P.
F.P. = I.P./B.P.
The term scavenging is generally associated with
2-stroke cycle engines
4-stroke cycle engines
Aeroplane engines
High efficiency engines
The cam shaft of a four stroke I.C. engine running at 1500 rpm will run at
1500 rpm
750 rpm
3000 rpm
Any value independent of engine speed
In a typical medium speed 4-stroke cycle diesel engines
Exhaust valve opens at 35° before bottom dead centre and closes at 20° after top dead centre
Exhaust valve opens at bottom dead centre and closes at top dead centre
Exhaust valve opens just after bottom dead centre and closes just before top dead centre
May open and close anywhere
The thermodynamic cycle on which the petrol engine works, is
Otto cycle
Joule cycle
Rankine cycle
Stirling cycle