PRE-IGNITION DETERMINING APPARATUS FOR INTERNAL COMBUSTION ENGINE

A pre-ignition determining apparatus for an internal combustion engine using hydrogen as fuel is configured to determine an occurrence of pre-ignition based on an output value of a vibration sensor provided in the internal combustion engine. The pre-ignition determining apparatus includes processing circuitry that is configured to execute an accumulation process of calculating an accumulated value of the output value within a prescribed period prior to an ignition timing of an air-fuel mixture, and a determination process of determining the occurrence of pre-ignition based on the accumulated value.