CONTROLLER FOR HYDROGEN ENGINE

A controller for a hydrogen engine that includes an in-cylinder pressure sensor and an air-fuel ratio sensor includes processing circuitry. The processing circuitry is configured to execute a process that calculates a fluctuation amount of a combustion pressure based on an output of the in-cylinder pressure sensor and a process that calculates a correction amount based on the fluctuation amount. The correction amount is used to correct a rich deviation of an output of the air-fuel ratio sensor due to unburned hydrogen in exhaust gas.