Knocking control system for gas engine

A knocking control system for a gas engine comprising:

• an ignition device for igniting an air-fuel mixture supplied to the gas engine;
• a knocking detector for detecting a knocking in a cylinder of the gas engine;
• a phase angle detector for detecting a phase angle of the gas engine;
• and
• a controller for driving the ignition device, the controller being configured to calculate a knocking occurrence ratio defined as a value obtained by dividing a determined number of cycles in which knocking occurs within a predetermined number of cycles by the predetermined number of cycles, perform a delay calculation of the knocking occurrence ratio to calculate an occurrence ratio delay calculation value, calculate a deviation between the occurrence ratio delay calculation value and a predetermined occurrence ratio target value, and drive the ignition device so that the ignition timing reaches a command value decided according to a target value of the ignition timing of the ignition device, by retarding the target value of the ignition timing of the ignition device based on the deviation if the occurrence ratio delay calculation value is larger than the occurrence ratio target value, and by advancing the target value of the ignition timing of the ignition device based on the deviation if the occurrence ratio delay calculation value is smaller than the occurrence ratio target value.