Question

Which of the following factors affecting combustion in the CI engine?

(a) compression ratio

(b) intake temperature

(c) jacket water temperature

(d) all of the mentioned

This question was posed to me during an interview.

The above asked question is from Combustion in C.I. Engine in division Combustion and Combustion Chambers of IC Engine

Answer 1

The correct answer is:

(d) all of the mentioned

Explanation: All the factors listed affect combustion in a Compression Ignition (C.I.) engine:

• Compression ratio: The compression ratio is a critical factor in C.I. engine combustion. A higher compression ratio increases the pressure and temperature of the air-fuel mixture, which helps to promote more efficient combustion and improves engine performance. It also influences ignition delay and the onset of combustion.

• Intake temperature: The temperature of the air entering the combustion chamber affects the density and energy of the air-fuel mixture. Warmer intake air can reduce the ignition delay and promote smoother combustion, while colder air may increase the delay.

• Jacket water temperature: The temperature of the coolant (jacket water) affects the engine's overall thermal management. If the water temperature is too low, it can result in poor combustion, incomplete fuel burning, and increased emissions. Conversely, if it is too high, it may lead to engine knock or overheating, affecting performance and efficiency.

Thus, all of these factors are interrelated and crucial in ensuring proper combustion and optimal engine performance.