Methods and apparatus to detect and inhibit low-speed pre-ignition in an engine

The disclosure provides a method of detecting and inhibiting an abnormal combustion event in an internal combustion engine, comprising operating the internal combustion engine to produce exhaust gas from the cylinder at a break mean effective pressure greater than or equal to 10 bars at a speed less than or equal to 2,000 revolutions per minute; monitoring the exhaust gas from the cylinder with an oxygen sensor while the internal combustion engine undergoes a pre-ignition combustion event; obtaining an output from the oxygen sensor, the output from the oxygen sensor providing an indicator of the pre-ignition combustion event; and adjusting at least one operating parameter of the internal combustion engine in response to the output of the oxygen sensor, wherein the at least one operating parameter is adjusted to inhibit an occurrence of a subsequent pre-ignition combustion event.