Study of knock in a high compression ratio spark-ignition methanol engine by multi-dimensional simulation

► Knock in a high compression ratio spark-ignition methanol engine was simulated. ► Because the compression ratio is very high, it could not fully suppress knock solely by retarding the spark timing. ► With the increase of EGR, the knock could be effectively suppressed, the peak pressure was reduced and postponed. ► Knock intensity had a maximum point, rich mixture and lean mixture can help reduce knock intensity. ► In order to reduce engine knock intensity, two feasible new combustion chambers were proposed.