Ionization misfire detection apparatus and method for an internal combustion engine
AssigneeChrysler Corporation
InventorJay C. McCombie
Life of this patent
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Abstract
A misfire detection apparatus and method is provided for detecting misfire in cylinders of an internal combustion engine in a motor vehicle. The method includes sensing ionization current through spark plugs in either a distributorless ignition system or a distributor ignition system. The method also includes disabling ionization current sensing during ignition coil discharge time. The method further includes making and storing the combustion ionization measurements in order to determine if a misfire has occurred and if catalyst damage has occurred due to the misfire.
Claims15
A method of detecting misfire in cylinders of an internal combustion engine in a vehicle, said method comprising the steps of:
- synchronizing combustion ionization measurements to an engine synchronous cylinder;
- making combustion ionization measurements;
- determining if misfire has occurred based on the combustion ionization measurements;
- testing for catalyst damage and for at least one failed predetermined test requirement due to misfire occurring;
- and
- signaling a vehicle operator if a fault has occurred as a result of the testing.
A method of detecting misfire in cylinders of an internal combustion engine in a vehicle, said method comprising the steps of:
- determining if the engine is in synchronization for performing combustion ionization measurements;
- making combustion ionization measurements if the engine is in synchronization for performing combustion ionization measurements;
- determining if misfire has occurred based on the combustion ionization measurements;
- testing for catalyst damage and for at least one failed predetermined test requirement if misfire has occurred;
- and
- signaling a vehicle operator if a fault has occurred as a result of the testing.
A method of detecting misfire in cylinders of an internal combustion engine in a vehicle, said method comprising the steps of:
- synchronizing combustion ionization measurements to engine position;
- reading combustion ionization data;
- determining if the ionization data is ready to be processed and determining whether predetermined conditions have been met if the ionization data is ready to be processed;
- determining if misfire has occurred based on the ionization data if the predetermined conditions have been met;
- testing for catalyst damage and for at least one failed predetermined test requirement if misfire has occurred;
- and
- signaling a vehicle operator if a fault has occurred as a result of the testing.
A method of detecting misfire in cylinders of an internal combustion engine in a vehicle, said method comprising the steps of:
- synchronizing combustion ionization measurements to engine position;
- reading combustion ionization data;
- determining if the ionization data is ready to be processed, determining whether predetermined conditions have been met if the ionization data is ready to be processed, and determining a current load factor on the engine if the predetermined conditions have been met;
- determining if misfire has occurred based on the ionization data;
- testing for catalyst damage and for at least one failed predetermined test requirement if misfire has occurred;
- and
- signaling a vehicle operator if a fault has occurred as a result of the testing.
A method of detecting misfire in cylinders of an internal combustion engine in a vehicle, said method comprising the steps of:
- synchronizing combustion ionization measurements to engine position;
- reading combustion ionization data;
- determining if the combustion ionization data is ready to be processed, determining whether predetermined conditions have been met if the combustion ionization data is ready to be processed, and determining a current load factor on the engine if the predetermined conditions have been met;
- finding a shorted spark plug ionization threshold and finding a minimum ionization for combustion threshold;
- calculating a cylinder identification and then proceeding to a corresponding cylinder service routine;
- calculating a drift term whereby minor parallel d.c. current or circuit drift are compensated for;
- evaluating a predetermined cylinder for a possible misfire;
- testing for catalyst damage and for at least one failed predetermined test requirement if misfire has occurred;
- and
- signaling a vehicle operator if a fault has occurred as a result of the testing.
Dependencies are inferred from the claim text.