Patent ID: 6801848
Filing Date: 2004-10-05
Classification: G01M

Abstract:
An apparatus for sensing a misfire in an internal combustion engine and for providing a misfire indication signal in response to the occurrence of the misfire, the apparatus comprising:at least one cylinder of the internal combustion engine, said cylinder having a cylinder event during which fuel is combusted in said cylinder, said cylinder delivering a certain magnitude of torque during said cylinder event, said cylinder event having a time period that is inversely proportional to said magnitude of said torque; said cylinder being capable of a misfire during said cylinder event thereof and consequently providing torque of a reduced magnitude during said misfire cylinder event as a result of said misfire; and an electronic controller that is configured to: calculate an expected time period for a cylinder event to provide an expected time period value; measure the actual time period of said cylinder event to provide a measured time period value; and calculate the difference between said expected time period value and said measured time period value to provide a difference time period value; compare said difference time period value to a predetermined threshold time; and provide the misfire indication signal in response to said difference time period value exceeding said predetermined threshold time.