A petrol engine, during suction stroke draws
Air only
Petrol only
A mixture of petrol and air
None of these
Correct Answer :
C. A mixture of petrol and air
Related Questions
The air-fuel ratio of the petrol engine is controlled by
Carburettor
Injector
Governor
None of these
The turbine of the turboprop engine is __________ that of the turbojet engine.
Same as
Smaller than
Bigger than
None of these
The operation of forcing additional air under pressure into the engine cylinder is known as
Supercharging
Carburetion
Turbulence
Delay period
Which is more viscous lube oil?
SEA 30
SAE 50
SAE 70
SAE 80
Which of the following statement is correct regarding petrol engines?
A fine fuel spray mixed with air is ignited by the heat of compression which is at a high pressure
The fuel supplied to the engine cylinder is mixed with necessary amount of air and the mixture in ignited with the help of a spark plug
The fuel is first evaporated after passing through a carburettor and is mixed with air before ignition
All of the above
Diesel as compared to petrol is
Highly ignitable
More difficult to ignite
Less difficult to ignite
None of these
The air-fuel ratio in petrol engines is controlled by
Controlling valve opening/closing
Governing
Injection
Carburetion
Pick up the wrong statement about supercharging
Supercharging reduces knocking in diesel engines
There can be limited supercharging in petrol engines because of detonation
Supercharging at high altitudes is essential
Supercharging results in fuel economy
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
The spark ignition engines are governed by
Hit and miss governing
Qualitative governing
Quantitative governing
Combination of (B) and (C)
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
In case of gas turbines, the gaseous fuel consumption guarantees are based on
High heat value
Low heat value
Net calorific value
Calorific value
Which of the following fuel has little tendency towards detonation?
Benzene
Iso-octane
Normal heptane
Alcohol
Which of the following fuel detonates readily?
Benzene
Iso-octane
Normal heptane
Alcohol
If the intake air temperature of I.C. engine increases, its efficiency will
Increase
Decrease
Remain same
None of these
In a diesel engine, the fuel is ignited by
Spark
Injected fuel
Heat resulting from compressing air that is supplied for combustion
Ignition
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
Which of the following is the lightest and most volatile liquid fuel?
Diesel
Kerosene
Fuel oil
Gasoline
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
Pour point of fuel oil is the
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
Supercharging is the process of supplying the intake air to the engine cylinder at a density _________ the density of the surrounding atmosphere.
Equal to
Less than
Greater than
None of these
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
The self ignition temperature of petrol is ________ as compared to diesel oil.
Same
Lower
Higher
None of these
Diesel engine can work on very lean air fuel ratio of the order of 30: 1. A petrol engine can also work on such a lean ratio provided
It is properly designed
Best quality fuel is used
Cannot work as it is impossible
Flywheel size is proper
In a cycle, the spark lasts roughly for
1 sec
0.1 sec
0.01 sec
0.001 sec
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
A diesel engine has
1 valve
2 valves
3 valves
4 valves
Polymerisation is a chemical process in which molecules of a compound become
Larger
Slowed down
Smaller
Liquid
A spark plug gap is kept from
0.3 to 0.7 mm
0.2 to 0.8 mm
0.4 to 0.9 mm
0.6 to 1.0 mm
A heat engine utilises the
Calorific value of oil
Low heat value of
High heat value of oil
Mean heat value of oil