Investigations have been made into control of knock in spark-ignited dedicated gas engines. Knock is a limiting factor determining the realisable rating of a spark ignited engine, and constraining the selection of fuelling and ignition characteristics for optimum efficiency and emissions.
The knock phenomenon was studied using four multi-cylinder engines widely used in heavy transport applications, and adapted to high compression spark ignition with natural gas fuelling. Appropriate knock control strategies were developed and refined to accommodate the demands of field application in multi-cylinder engines.
A knock control unit is operative for particular engines on which it has been characterised. Continuing development will include use of adaptive control technology to increase the system's versatility for a variety of engine applications.