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
Correct Answer :
D. Detonation
Related Questions
The advancing of spark timing in spark ignition engines will _________ knocking tendency.
Increase
Reduce
Not effect
None of these
The scavenging efficiency of a four stroke cycle diesel engine is
Below 50%
Between 50 and 85%
Between 85 and 95%
Between 95 and 100%
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
The basic requirement of a good combustion chamber is
Minimum turbulence
Low compression ratio
High thermal efficiency and power output
Low volumetric efficiency
The cetane (C16H34) which is a straight chain paraffin, is assigned a cetane number of
0
50
100
120
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
Polymerisation is a chemical process in which molecules of a compound become
Larger
Slowed down
Smaller
Liquid
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
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
The magneto in an automobile is basically
Transformer
D.C. generator
Capacitor
Magnetic circuit
The voltage required to produce a spark across the gap, between the sparking points is
2000 to 4000 volts
4000 to 6000 volts
6000 to 10,000 volts
10,000 to 12,000 volts
The air-fuel ratio in petrol engines is controlled by
Controlling valve opening/closing
Governing
Injection
Carburetion
Diesel as compared to petrol is
Highly ignitable
More difficult to ignite
Less difficult to ignite
None of these
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 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
Supercharging is the process of
Supplying the intake of an engine with air at a density greater than the density of the surrounding atmosphere
Providing forced cooling air
Injecting excess fuel for raising more loads
Supplying compressed air to remove combustion products fully
In a typical medium speed 4-stroke cycle diesel engine
Compression starts at 35° after bottom dead center and ends at top dead center
Compression starts at bottom dead center and ends at top dead center
Compression starts at 10° before bottom dead center and, ends just before top dead center
May start and end anywhere
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
The combustion in compression ignition engines is
Homogeneous
Heterogeneous
Both (A) and (B)
None of these
An engine indicator is used to determine the following
Speed
Temperature
Volume of cylinder
m.e.p. and I.H.P.
A 5 BHP engine running at full load would consume diesel of the order of
0.3 kg/hr
1 kg/hr
3 kg/hr
5 kg/hr
A diesel engine has
1 valve
2 valves
3 valves
4 valves
Which of the following fuel detonates readily?
Benzene
Iso-octane
Normal heptane
Alcohol
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
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
Combustion in compression ignition engines is
Homogeneous
Heterogeneous
Both (A) and (B)
Laminar
The increase of cooling water temperature in petrol engine will __________ the knocking tendency.
Not effect
Decrease
Increase
None of these
The inlet value of a four stroke cycle I.C engine remains open for nearly
180°
125°
235°
200°
The temperature of interior surface of cylinder wall in normal operation is not allowed to exceed
80°C
120°C
180°C
240°C
In a diesel engine, the duration between the time of injection and ignition, is known as
Pre-ignition period
Delay period
Period of ignition
Burning period