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Mechanical Engineering · Q48

Internal Combustion Engines (I.C. Engines)

Engineering and GATE · Mechanical Engineering · question 48

Q48

In order to eliminate knocking in compression ignition engines, there should be

A.
Short delay period
Answer
B.
Late auto-ignition
C.
Low compression ratio
D.
High self ignition temperature of fuel

Answer: Option A

Solution

Answer: Option A
Solution:
In order to eliminate knocking in compression ignition engines, there should be short delay period.
- Add 1% of ethyl nitrate or any nitrate to accelerate the combustion of fuel. This process is known as “Doping” and reduce delay period considerably and hence prevent diesel knock.
- For spontaneous ignition of the fuel, we require much higher temperature this can be achieved by raising the compression ratio.