Effect of supercharging on knocking tendency in a petrol (SI) engine with fixed fuel octane and fixed compression ratio. Fill the blank: Supercharging will ______ the knocking tendency under these constraints. Choose the correct effect.

Concept/ApproachSupercharging raises the inlet density and pressure, leading to higher end-gas temperature and pressure during compression. For a fixed octane rating and fixed geometric compression ratio, this promotes auto-ignition.

MechanismHigher charge density → higher charge temperature after compression → reduced knock margin → increased knocking tendency.

Final AnswerIncrease.