The volumetric efficiency of a well designed engine may be
30 to 40 %
40 to 60 %
60 to 70 %
75 to 90 %
Correct Answer :
D. 75 to 90 %
Related Questions
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
The cetane number of diesel oil, generally available, is
20 to 25
25 to 30
30 to 40
40 to 55
The turbine of the turboprop engine is __________ that of the turbojet engine.
Same as
Smaller than
Bigger than
None of these
In compression ignition engines, swirl denotes a
Haphazard motion of the gases in the chamber
Rotary motion of the gases in the chamber
Radial motion of the gases in the chamber
None of the above
The sensing element in the control system of nuclear reactors measures the _________ of the neutron flux in the reactor.
Temperature
Volume
Density
None of these
Which one of the following engines will have heavier flywheel than the remaining ones?
30 kW four-stroke petrol engine running at 1500 r.p.m.
30 kW two-stroke petrol engine running at 1500 r.p.m.
30 kW two-stroke diesel engine running at 750 r.p.m.
30 kW four-stroke diesel engine running at 750 r.p.m.
The specific fuel consumption per B.P. hour for a diesel engine is about
0.2 kg
0.25 kg
0.3 kg
0.35 kg
In a four stroke cycle engine, the sequence of operations is
Suction, compression, expansion and exhaust
Suction, expansion, compression and exhaust
Expansion, compression, suction and exhaust
Compression, expansion, suction and exhaust
A stoichiometric air-fuel ratio is
Chemically correct mixture
Lean mixture
Rich mixture for idling
Rich mixture for over loads
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
The pressure inside the cylinder is _________ the atmospheric pressure during the exhaust stroke.
Equal to
Below
Above
None of these
A two stroke cycle engine gives ________ the number of power strokes as compared to the four stroke cycle engine, at the same engine speed.
Half
Same
Double
Four times
The knock in diesel engine occurs due to
Instantaneous and rapid burning of the first part of the charge
Instantaneous auto ignition of last part of charge
Delayed burning of the first part of the charge
Reduction of delay period
The maximum propulsive efficiency of a turbojet engine is at a speed of
1000 km/h
2000 km/h
2400 km/h
3000 km/h
The purpose of testing an internal combustion engine is
To determine the information, which cannot be obtained by calculations
To conform the data used in design, the validity of which may be doubtful
To satisfy the customer regarding the performance of the engine
All of the above
The accumulation of carbon in a cylinder results in increase of
Clearance volume
Volumetric efficiency
Ignition time
Effective compression ratio
Which of the following is false statement? Some of the methods used to reduce diesel smoke are as follows
Using additives in the fuel
Increasing the compression ratio
Adherence to proper fuel specification
Avoidance of overloading
If the compression ratio in I.C. engine increases, then its thermal efficiency will
Decrease
Increase
Remain same
None of these
The object of supercharging the engine is
To reduce mass of the engine per brake power
To reduce space occupied by the engine
To increase the power output of an engine when greater power is required
All of the above
Supercharging is essential in
Diesel engines
Gas turbines
Petrol engines
Aircraft engines
Which of the following fuel has little tendency towards detonation?
Benzene
Iso-octane
Normal heptane
Alcohol
The following volume of air is required for consuming 1 litre of fuel by a four stroke engine
1 m3
5 m3
56 m3
910 m3
Which of the following fuel detonates readily?
Benzene
Iso-octane
Normal heptane
Alcohol
The mean effective pressure obtained from engine indicator indicates the
Maximum pressure developed
Minimum pressure
Instantaneous pressure at any instant
Average pressure
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
Number of working strokes per min. for a four stroke cycle engine are _________ the speed of the engine in r.p.m.
Equal to
One-half
Twice
Four-times
In petrol engines, advancing of the spark timing will _________ the knocking tendency.
Not effect
Decrease
Increase
None of these
The function of a distributor in a coil ignition system of I.C. engines is
To distribute spark
To distribute power
To distribute current
To time the spark
The theoretically correct air fuel ratio for petrol engine is of the order of
6 : 1
9 : 1
12 : 1
15 : 1
The temperature of interior surface of cylinder wall in normal operation is not allowed to exceed
80°C
120°C
180°C
240°C