In loop scavenging, the top of the piston is
Flat
Contoured
Slanted
Depressed
Correct Answer :
B. Contoured
Related Questions
In a typical medium speed 4-stroke cycle diesel engine the inlet valve
Opens at 20° before top dead center and closes at 35° after the bottom dead center
Opens at top dead center and closes at bottom dead center
Opens at 10° after top dead center and closes 20° before the bottom dead center
May open or close anywhere
The reflectivity depends upon
Geometry of the reflector
Energy of neutrons
Properties of the reflector
All of these
Diesel as compared to petrol is
Highly ignitable
More difficult to ignite
Less difficult to ignite
None of these
Gaseous fuel guarantees are based on
Calorific value of oil
Low heat value of oil
High heat value of oil
Mean heat value of oil
If the intake air temperature of I.C. engine increases, its efficiency will
Increase
Decrease
Remain same
None of these
In compression ignition engines, swirl denotes a
Haphazard motion of the gases in the chamber
Rotary motion of the gases in the chamber
Radial motion of the gases in the chamber
None of the above
The brake power is the power available
In the engine cylinder
At the crank shaft
At the crank pin
None of these
Most high speed compression engines operate on
Otto cycle
Diesel cycle
Dual cycle
Carnot cycle
For the same power developed in I.C. engines, the cheaper system is
Naturally aspirated
Supercharged
Centrifugal pump
Turbo charger
A heat engine utilises the
Calorific value of oil
Low heat value of
High heat value of oil
Mean heat value of oil
In order to eliminate knocking in compression ignition engines, there should be
Short delay period
Late auto-ignition
Low compression ratio
High self ignition temperature of fuel
The compression ignition engines are governed by
Hit and miss governing
Qualitative governing
Quantitative governing
Combination of (B) and (C)
A supercharged engine as compared to an ordinary engine
Requires smaller foundation
Is lighter
Consumes less lubricating oil
All of these
In the crankcase method of scavenging, the air pressure is produced by
Supercharger
Centrifugal pump
Natural aspirator
Movement of engine piston
The injection pressure in a diesel engine is about
10 bar
100 bar
150 bar
500 bar
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
Which of the following is the lightest and most volatile liquid fuel?
Diesel
Kerosene
Fuel oil
Gasoline
The cetane (C16H34) which is a straight chain paraffin, is assigned a cetane number of
0
50
100
120
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 ignition quality of diesel oil is expressed by
Cetane number
Octane number
Calorific value
None of these
In the opposed piston diesel engine, the combustion chamber is located
Above the piston
Below the piston
Between the pistons
There is no such criterion
The calorific value of gaseous fuels is expressed in terms of
kcal
kcal/kg
kcal/m²
kcal/m3
Morse test is used to determine the I.P. of a
Single cylinder petrol engine
Four stroke engine
Single cylinder diesel engine
Multi cylinder engine
The rating of a diesel engine, with increase in air inlet temperature, will
Increase linearly
Decrease linearly
Increase parabolically
Decrease parabolically
The increase in intake temperature of internal combustion engines will _________ efficiency.
Have no effect on
Increase
Decrease
None of these
The maximum temperature in the I.C. engine cylinder is of the order of
500-1000°C
1000-1500°C
1500-2000°C
2000-2500°C
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
Polymerisation is a chemical process in which molecules of a compound become
Larger
Slowed down
Smaller
Liquid
If one cylinder of a diesel engine receives more fuel than the others, then for that cylinder the
Exhaust will be smoky
Piston rings would stick into piston grooves
Engine starts overheating
Scavenging occurs
The advancing of spark timing in spark ignition engines will _________ knocking tendency.
Increase
Reduce
Not effect
None of these