Question

The rate of pressure rise depends on the amount of fuel present at the end of delay period, degree of turbulence, fineness of atomization and spray pattern.

(a) True

(b) False

The question was asked in a national level competition.

My query is from Combustion in C.I. Engine in division Combustion and Combustion Chambers of IC Engine

Answer 1

The correct answer is:

(a) True

Explanation: The rate of pressure rise in a Compression Ignition (C.I.) engine is influenced by several factors, including:

• Amount of fuel present at the end of the delay period: The amount of fuel injected into the combustion chamber during the delay period (the time between injection and ignition) directly affects the rate of pressure rise. More fuel means a greater heat release, leading to a faster pressure increase.

• Degree of turbulence: Turbulence within the combustion chamber plays a key role in the mixing of air and fuel. Higher turbulence enhances fuel-air mixing, leading to more efficient combustion and a higher rate of pressure rise.

• Fineness of atomization: The finer the atomization (i.e., the smaller the fuel droplets), the better the air-fuel mixing. Smaller droplets burn more efficiently, resulting in a quicker and more uniform pressure rise.

• Spray pattern: The pattern of the fuel spray affects how evenly the fuel is distributed in the combustion chamber. A well-distributed spray pattern enhances combustion efficiency and contributes to a faster and more uniform pressure rise.

Thus, all these factors play a significant role in determining the rate at which pressure rises during combustion in a C.I. engine.