Question

What are the phases of CI engine combustion?

(a) ignition delay period

(b) period of rapid combustion

(c) period of controlled combustion

(d) all of the mentioned

This question was addressed to me in unit test.

The origin of the question is Combustion in C.I. Engine in section Combustion and Combustion Chambers of IC Engine

Answer 1

The correct answer is:

(d) all of the mentioned

Explanation: The combustion process in a Compression Ignition (C.I.) engine is typically divided into three main phases:

1. Ignition delay period: This is the time interval between the start of fuel injection and the ignition of the fuel due to the high temperature and pressure in the combustion chamber. During this phase, the injected fuel undergoes a series of chemical reactions before it ignites.

2. Period of rapid combustion: Once ignition occurs, there is a rapid rise in pressure and temperature as the fuel burns. This phase is characterized by the almost immediate release of heat from the combustion of the injected fuel.

3. Period of controlled combustion: After the initial rapid combustion, the process transitions to a more controlled burn. In this phase, the combustion continues at a steady rate, and the pressure gradually rises to its peak value. The fuel is burned more efficiently during this phase, and it influences the overall engine performance and emissions.

All three phases are integral to the overall combustion process in a C.I. engine.