Question

In compression ignition engines, swirl denotes a __________

(a) haphazard motion of the gases in the chamber

(b) rotary motion of the gases in the chamber

(c) radial motion of the gases in the chamber

(d) none of the mentioned

This question was posed to me in class test.

I need to ask this question from Comparison of Two Stroke S.I. and C.I. Engines topic in chapter Two Stroke Engines of IC Engine

Answer 1

The correct answer is:

**(b) rotary motion of the gases in the chamber**

In compression ignition (CI) engines, *swirl* refers to the organized rotary or swirling motion of the air (or gases) within the combustion chamber. This motion enhances the mixing of air and fuel, leading to more efficient combustion. Swirl is intentionally created to improve air-fuel mixture formation and ensure a controlled, complete burn in CI engines.