Mechanical Engineering - IC Engines and Nuclear Power Plants - Discussion

In petrol engine, knocking occurs due to rise in temp. Of mixture therefore if more comoression ratio used then large compression will occur resulting in more pressure rise and as pressure will rise, temperature will too. Therefore in peteol engine, increasing compression ratio increases knocking but in diesel engine if more compression ratio is there then more air can be conpressed and more higher pressure can be achieved resulting high temp. And fuel will burn instantly so no knocking.

The answer should be A.

Raising the compression ratio increases knocking.