Engine converter misfire protection method and apparatus

摘要

An engine catalytic converter misfire protection method and apparatus which controls engine parameters in response to the detection of potentially damaging cylinder misfire. A misfire counter responsive to engine cylinder misfires, counts misfires over a predetermined time period, with the positive changes in the counter output integrated and then compared with a threshold count to determine if the count corresponds to a damaging misfire condition. The apparatus and method simultaneously samples a short term fuel correction signal and compares the short term fuel correction signal with a second threshold. When both thresholds are exceeded substantially at the same time, the apparatus and method shut off fuel to the misfiring cylinder and shuts off the short and long term fuel control. Verification that the proper cylinder has the fuel shut off is made by repeating the control sequence to determine if the fuel has been shut off to the same cylinders.