Question

Auto ignition refers to the initiation of combustion without the necessity of a flame.

(a) True

(b) False

The question was posed to me during an interview for a job.

The doubt is from Knocking in S.I. Engine in chapter Combustion and Combustion Chambers of IC Engine

Answer 1

The correct answer is:

(a) True

Explanation: Auto ignition refers to the ignition of the air-fuel mixture without the need for an external flame source, such as a spark plug. This occurs when the temperature and pressure in the combustion chamber reach a level sufficient to ignite the fuel spontaneously. Auto ignition is a key phenomenon in Compression Ignition (C.I.) engines, where fuel ignites due to high compression. However, in Spark Ignition (S.I.) engines, auto ignition is undesirable and leads to knocking, where parts of the mixture ignite prematurely due to high pressure and temperature, rather than in a controlled manner by the spark plug.