Question

Use of low octane fuel can eliminate detonation.

(a) True

(b) False

The question was posed to me during an internship interview.

My question is taken from Knocking in S.I. Engine in division Combustion and Combustion Chambers of IC Engine

Answer 1

The correct answer is:

(b) False

Explanation: Low octane fuel does not eliminate detonation; rather, it tends to increase the likelihood of detonation (also called knocking). In a Spark Ignition (S.I.) engine, detonation occurs when the air-fuel mixture ignites prematurely, causing abnormal combustion. Octane rating measures a fuel's resistance to knocking. Higher octane fuels have a higher resistance to premature ignition and detonation, while lower octane fuels are more likely to cause knocking under high load or high compression conditions. Therefore, using low octane fuel actually increases the risk of detonation, not eliminates it.