Abstract: Engine systems and methods use a dual air injection approach to control exhaust reactions and to maintain temperatures below a maximum limit of exhaust system components during engine enrichment operation conditions. Dual air injectors are disposed in the exhaust system with one upstream from, and another downstream from, the catalytic converter. Providing air injection before and/or after the converter helps convert all HC, CO, and PM emissions while keeping the catalyst temperature below the catalyst protection temperature limit. Air injection quantity may be controlled and diagnosed by monitoring the temperatures before and after the catalytic converter. The catalytic converter may be a three-way catalytic converter for lower cost or a downstream two-way catalytic converter may be added if further emission reduction is necessary.

Abstract: A system for and a method of knock detection and control for an engine utilizes a knock sensor configured to generate a knock signal indicative of a vibration of the engine caused by abnormal combustion. A controller is configured to receive the knock signal, determine, with respect to a crank angle of the engine, distinct monitoring windows for low speed pre-ignition (LSPI) knock and spark knock, respectively, based on (i) spark timing and (ii) an appropriate mass fraction burn (MFB) location, monitor the knock signal using the distinct monitoring windows, detect one of LSPI knock and spark knock based on the monitoring, and control the engine to mitigate the detected LSPI knock or spark knock.

Abstract: A system for and a method of knock detection and control for an engine utilizes a knock sensor configured to generate a knock signal indicative of a vibration of the engine caused by abnormal combustion. A controller is configured to receive the knock signal, determine, with respect to a crank angle of the engine, distinct monitoring windows for low speed pre-ignition (LSPI) knock and spark knock, respectively, based on (i) spark timing and (ii) an appropriate mass fraction burn (MFB) location, monitor the knock signal using the distinct monitoring windows, detect one of LSPI knock and spark knock based on the monitoring, and control the engine to mitigate the detected LSPI knock or spark knock.