Question

The ignition timings and thermal load on the engine affect the knock limit of _____________ engine.

(a) SI

(b) CI

(c) SI & CI

(d) None of the mentioned

I have been asked this question during an interview.

This key question is from Effects of Supercharging in division Supercharging of IC Engine

Answer 1

Answer: (a) SI

Explanation: The ignition timings and thermal load on the engine primarily affect the knock limit of a Spark Ignition (SI) engine. In SI engines, knocking (pre-detonation) is influenced by factors such as spark timing, air-fuel mixture, and engine temperature. Advancing the ignition timing or increasing the thermal load can lead to earlier ignition, which can cause knocking. In contrast, Compression Ignition (CI) engines are more affected by compression ratio and fuel characteristics, not directly by ignition timing.