knock and detonation

are knock and detonation both same? If not what causes them and when does that occur?

Yes, they are the same thing. I personally perfer “detonation” as it refers to the shockwave as occurs in the detonation of high-order explosives, which in priciple is the same kind of combustion as what is happening in your engine when it is detonating.

Knock is a more general word, but yes, it describes the same thing thing and I know this is High Performance Academy, not Highly Pedantic Linguistics lol.

'Highly Pedantic Linguistics' XD

Matt pretty much has you sorted, but I'll just add some extra resources for you Abhishek:

https://www.hpacademy.com/technical-articles/dont-waste-your-time-listening-for-knock/

https://www.hpacademy.com/previous-webinars/130-what-is-knock-essential-knowledge/

https://www.hpacademy.com/previous-webinars/083-understanding-knock/