The knocking tendency in compression ignition engines for a given fuel will be

A Enhanced by decreasing compression ratio
B Enhanced by increasing compression ratio
C Dependent on other factors
D None of the above

Correct Answer: Enhanced by decreasing compression ratio

The knocking tendency in compression ignition engines for a given fuel will be Enhanced by decreasing compression ratio.In SI engine, knocking tendency increases with increase in compression ratio. ... In CI engine, knocking tendency decreases with increase in compression ratio. If compression ratio is low in CI engine, there will not be enough temperature generation for ignition of the fuel air mixture.
Bissoy MCQ
#Mechanical Engineering #Internal Combustion Engines (I.C. Engines)

Related Questions

The higher combustion chamber wall temperature in compression ignition engines will _________ knocking tendency.
A Increase
B Reduce
C Not effect
D None of these
The advancing of spark timing in spark ignition engines will _________ knocking tendency.
A Increase
B Reduce
C Not effect
D None of these
In order to eliminate knocking in compression ignition engines, there should be
A Short delay period
B Late auto-ignition
C Low compression ratio
D High self ignition temperature of fuel
In petrol engine, using a fixed octane rating fuel and fixed compression ratio, supercharging will _________ the knocking tendency.
A Not effected
B Decrease
C Increase
D None of these
With increase in __________ Knocking tendency in a spark ignition petrol engine decreases.
A Supercharging
B Wall temperature
C Compression ratio
D Engine speed
In petrol engines, advancing of the spark timing will _________ the knocking tendency.
A Not effect
B Decrease
C Increase
D None of these
In order to prevent knocking in spark ignition engines, the charge away from the spark plug should have
A Low density
B Low temperature
C Long ignition delay
D All of these
The knocking in spark ignition engines can be reduced by
A Retarding the spark
B Increasing the engine speed
C Both (A) and (B)
D None of these
The fuels in order of decreasing knock tendency for spark ignition engines are
A Paraffin, aromatic, napthene
B Paraffin, napthene, aromatic
C Napthene, aromatics, paraffin
D Napthene, paraffin, aromatic
The compression ignition engines are governed by
A Hit and miss governing
B Qualitative governing
C Quantitative governing
D Combination of (B) and (C)

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