A diesel engine has
One valve
Two valves
Three valves
Four valves
Correct Answer :
C. Three valves
Related Questions
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 air standard efficiency of an I.C. engine depends on
Fuel used
Speed of engine
Compression ratio
None of these
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
Which of the following fuel has little tendency towards detonation?
Benzene
Iso-octane
Normal heptane
Alcohol
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
In a diesel engine, the fuel is ignited by
Spark
Injected fuel
Heat resulting from compressing air that is supplied for combustion
Ignition
Which of the following is the lightest and most volatile liquid fuel?
Diesel
Kerosene
Fuel oil
Gasoline
Which of the following statement is wrong?
In compression ignition engines, detonation occurs near the beginning of combustion.
Since the fuel, in compression ignition engines, is injected at the end of compression stroke, therefore, there will be no pre-ignition.
To eliminate knock in compression ignition engines, we want to achieve auto-ignition not early and desire a long delay period.
In compression ignition engines, because of heterogeneous mixture, the rate of pressure rise is comparatively lower.
The ignition of the charge by some hot surface within the engine before the passage of spark is called
Pre-ignition
Detonation
Ignition delay
Auto-ignition
The ignition quality of petrol is expressed by
Cetane number
Octane number
Calorific value
All of these
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
Which of the following is not an interns combustion engine?
2-stroke petrol engine
4-stroke petrol engine
Diesel engine
Steam turbine
The thermal efficiency of a petrol engine is _________ as compared to diesel engine.
Same
Less
More
None of these
As compared to air standard cycle, in actual working, the effect of variation in specific heats is to
Increase maximum pressure and maximum temperature
Reduce maximum pressure and maximum temperature
Increase maximum pressure and decrease maximum temperature
Decrease maximum pressure and increase maximum temperature
The reference fuels for knock rating of spark ignition engines would include
Iso-octane and alpha-methyl naphthalene
Normal octane and aniline
Isooctane and normal hexane
Normal heptane and isooctane
Which of the following statements is correct?
All the irreversible engines have same efficiency
All the reversible engines have same efficiency
Both Rankine and Carnot cycles have same efficiency between same temperature limits
All reversible engines working between same temperature limits have same efficiency
In a naturally aspirated diesel engine, the air is supplied by
A supercharger
A centrifugal blower
A vacuum chamber
An injection tube
In a cycle, the spark lasts roughly for
1 sec
0.1 sec
0.01 sec
0.001 sec
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 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
Pick up the wrong statement
2-stroke engine can run in any direction
In 4-stroke engine, a power stroke is obtained in 4-strokes
Thermal efficiency of 4-stroke engine is more due to positive scavenging
Petrol engines occupy more space than diesel engines for same power output
Which of the following fuel detonates readily?
Benzene
Iso-octane
Normal heptane
Alcohol
In a four stroke cycle petrol engine, the charge is ignited at
30° before top dead centre
30° after top dead centre
30° before bottom dead centre
30° after bottom dead centre
Most high speed compression engines operate on
Diesel cycle
Otto cycle
Dual combustion cycle
Special type of air cycle
Fuel oil consumption guarantees for I .C. engine are usually based on
Low heat value of oil
High heat value of oil
Net calorific value of oil
Calorific value of fuel
The theoretically correct mixture of air and petrol is
10 : 1
15 : 1
20 : 1
25 : 1
For the same compression ratio
Otto cycle is more efficient than the Diesel
Diesel cycle is more efficient than Otto
Both Otto and Diesel cycles are, equally efficient
Compression ratio has nothing to do with efficiency
The compensating jet in a carburettor supplies almost constant amount of petrol at all speeds because the
Jet area is automatically varied depending on the suction
The flow from the main jet is diverted to the compensating jet with increase in speed
The diameter of the jet is constant and the discharge coefficient is invariant
Flow is produced due to the static head in the float chamber
The thermal efficiency of a diesel cycle having fixed compression ratio, with increase in cut-off ratio will
Increase
Decrease
Be independent
May increase or decrease depending on other factors
Diesel as compared to petrol is
Highly ignitable
More difficult to ignite
Less difficult to ignite
None of these