In a petrol engine, the fuel supplied to the engine cylinder is mixed with required quantity of air and the mixture is ignited with a
Fuel pump
Fuel injector
Spark plug
None of these
Correct Answer :
C. Spark plug
Related Questions
The power actually developed by the engine cylinder of an I.C. engine is known as
Theoretical power
Actual power
Indicated power
None of these
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
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
A 75 cc engine has following parameter as 75 cc
Fuel tank capacity
Lube oil capacity
Swept volume
Cylinder volume
In diesel engine the diesel fuel injected into cylinder would burn instantly at about compressed air temperature of
250°C
500°C
1000°C
2000°C
The method of determination of indicated power of a multi cylinder spark ignition engine is by the use of
Morse test
Prony brake test
Motoring test
Heat balance test
In diesel engine, the compression ratio in comparison to expansion ratio is
Same
Less
More
Variable
Which of the following statement is correct regarding normal cetane?
It is a standard fuel used for knock rating of diesel engines
Its chemical name is normal hexadecane
It has long carbon chain structure
All of the above
The pressure and temperature at the end of compression stroke in a petrol engine are of the order of
4-6 kg/cm² and 200-250°C
6-12 kg/cm² and 250-350°C
12-20 kg/cm² and 350-450°C
20-30 kg/cm² and 450-500°C
The brake power (B.P.) of the engine is given by (where W = Brake load or dead load in newtons, l = Length of arm in metres, N = Speed of engine in r.p.m., S = Spring balance reading in newtons, D = Dia. of brake drum in metres, and d = Dia. of rope in metres)
B.P = (Wl × 2πN)/60 watts
B.P = [(W - S) πDN]/60 watts
B.P = [(W - S) π (D + d) N]/60 watts
All of these
The ratio of the brake power to the indicated power is called
Mechanical efficiency
Overall efficiency
Indicated thermal efficiency
Volumetric efficiency
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
The probability of knocking in diesel engines is increased by
High self ignition temperature
Low volatility
Higher viscosity
All 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
The thermal efficiency of a standard Otto cycle for a compression ratio of 5.5 will be
25 %
50 %
70 %
100 %
If the compression ratio of an engine working on Otto cycle is increased from 5 to 7, the percentage increase in efficiency will be
2 %
4 %
8 %
14 %
Flash point of 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
Temperature at which it catches fire without external aid
Indicated by 90% distillation temperature, i.e. when 90% of sample oil has distilled off
The cetane number of diesel oil, generally available, is
20 to 25
25 to 30
30 to 40
40 to 55
If the temperature of intake air in internal combustion engine increases, then its efficiency will
Remain same
Decrease
Increase
None of these
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
By higher octane number of spark ignition fuel, it is meant that the fuel has
Higher heating value
Higher flash point
Lower volatility
Longer ignition delay
The magneto in an automobile is basically
Transformer
D.C. generator
Capacitor
Magnetic circuit
The air-fuel ratio in petrol engines is controlled by
Controlling valve opening/closing
Governing
Injection
Carburetion
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
For the same power developed in I.C. engines, the cheaper system is
Naturally aspirated
Supercharged
Centrifugal pump
Turbo charger
If petrol is used in a diesel engine, then
Low power will be produced
Efficiency will be low
Higher knocking will occur
Black smoke will be produced
Which is more viscous lube oil?
SEA 30
SAE 50
SAE 70
SAE 80
The fuels in order of decreasing knock tendency for spark ignition engines are
Paraffin, aromatic, napthene
Paraffin, napthene, aromatic
Napthene, aromatics, paraffin
Napthene, paraffin, aromatic
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
An engine indicator is used to determine the following
Speed
Temperature
Volume of cylinder
m.e.p. and I.H.P.