The air-fuel ratio of the petrol engine is controlled by
Carburettor
Injector
Governor
None of these
Correct Answer :
A. Carburettor
Related Questions
The fuel in diesel engine is normally injected at pressure of
5-10 kg/cm²
20-25 kg/cm²
60-80 kg/cm²
90-130 kg/cm²
Which of the following statement is wrong?
A four stroke cycle engine develops twice the power as that of a two stroke cycle engine
For the same power developed, a four stroke cycle engine is lighter, less bulky and occupies less floor area
The petrol engines are costly than diesel engines
All of the above
The specific fuel consumption of a petrol engine compared to diesel engine of same H.P. is
Same
More
Less
Less or more depending on operating conditions
Scavenging is usually done to increase
Thermal efficiency
Speed
Power output
Fuel consumption
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
Alpha-methyl-naphthalene (C₁₁ H₁₀) has a cetane number of
0
50
100
120
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
Diesel fuel, compared to petrol is
Less difficult to ignite
Just about the same difficult to ignite
More difficult to ignite
Highly ignitable
Pre-ignition is caused by the spontaneous combustion of the mixture before the end of the compression stroke, and is due to
Cylinder walls being too hot
Overheated spark plug points
Red hot carbon deposits on cylinder walls
Any one of these
As a result of detonation in an I.C. engine, following parameter attains very high value
Peak pressure
Rate of rise of pressure
Rate of rise of temperature
Peak temperature
A gas engine has a swept volume of 300 cm3 and clearance volume of 25 cm3. Its volumetric efficiency is 0.88 and mechanical efficiency is 0.90. The volume of the mixture taken in per stroke is
248 cm3
252 cm3
264 cm3
286 cm3
In a naturally aspirated diesel engine, the air is supplied by
A supercharger
A centrifugal blower
A vacuum chamber
An injection tube
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
The combustion in compression ignition engines is
Homogeneous
Heterogeneous
Both (A) and (B)
None of these
In a typical medium speed, 4-stroke cycle diesel engine
Fuel injection starts at 10° before to dead center and ends at 20° after tor dead center
Fuel injection starts at top dead center and ends at 20° after top dead center
Fuel injection starts at just before top dead center and ends just after top dead center
May start and end anywhere
A higher compression ratio causes
Pre-ignition
Increase in detonation
Acceleration in the rate of combustion
Any one of these
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 higher combustion chamber wall temperature in compression ignition engines will _________ knocking tendency.
Increase
Reduce
Not effect
None of these
In a four stroke cycle petrol engine, the expansion
Starts at top dead centre and ends at bottom dead centre
Starts at 30° before top dead centre and ends at 50° before bottom dead centre
Starts at 30° after top dead centre and ends at 50° after bottom dead centre
May start and end anywhere
In a four stroke cycle petrol engine, the compression
Starts at 40° after bottom dead centre and ends at 30° before top dead centre
Starts at 40° before bottom dead centre and ends at 30° after bottom dead centre
Starts at bottom dead centre and ends at top dead centre
May start and end anywhere
During idling, a petrol engine requires _________ mixture.
Lean
Rich
Chemically correct
None of these
The ratio of the work obtained at the crankshaft in a given time to the energy supplied during the same time is called
Mechanical efficiency
Overall efficiency
Indicated thermal efficiency
Volumetric efficiency
If V₁ is the jet velocity and V₀ is the vehicle velocity, then propulsive efficiency of a turbojet engine is
V₁/(V₀ + V₁)
V₀/(V₀ + V₁)
2V₀/(V₀ + V₁)
2V₁/(V₀ + V₁)
In order to prevent knocking in spark ignition engines, the charge away from the spark plug should have
Low density
Low temperature
Long ignition delay
All of these
The thermal efficiency of petrol and gas engines is about
15 %
30 %
50 %
70 %
The size of inlet valve of an engine in comparison to exhaust valve is
More
Less
Same
More/less depending on capacity of engine
If V₁ is the jet velocity and V₀ is the vehicle velocity, then the propulsive efficiency of a rocket is given by
[2(V₀/V₁)]/ [1 + (V₀/V₁)²]
(V₀/V₁)/ [1 + (V₀/V₁)²]
V₀/(V₀ + V₁)
V₁/(V₀ + V₁)
The specific fuel consumption per BHP hour for diesel engine is approximately
0.15 kg
0.2 kg
0.25 kg
0.3 kg
The advancing of spark timing in spark ignition engines will _________ knocking tendency.
Increase
Reduce
Not effect
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.