Claims
- 1. Apparatus for predicting ignition system failures, comprising:
- an ignition coil having a primary coil coupled to a secondary coil;
- a spark plug connected to a high tension side and to a low tension side of said secondary coil and defining a spark gap therebetween;
- an ignition control circuit connected to said primary coil and having an input responsive to a firing command to energize said primary coil to thereby induce a spark voltage in said high tension side of said secondary coil and a corresponding spark in said spark gap, said spark voltage exhibiting a voltage peak having a peak value corresponding to a breakdown voltage of said spark gap; and
- a first computer having an input coupled to said high tension side of said secondary coil for receiving said spark voltage, said first computer comparing said peak value of said voltage peak with a threshold value and producing a prognostic signal corresponding to a predefined ignition system failure mode if said peak value is greater than said threshold value.
- 2. The apparatus of claim 1 wherein said first computer includes a first memory, said first computer storing in said first memory an error code corresponding to said prognostic signal.
- 3. The apparatus of claim 1 further including a second computer having an input receiving said prognostic signal and a second memory, said second computer storing in said second memory an error code corresponding to said prognostic signal.
- 4. The apparatus of claim 1 further including a voltage sensor associated with said high tension side of said secondary coil, said voltage sensor sensing said spark voltage and providing a spark voltage signal corresponding thereto to said input of said second computer.
- 5. The apparatus of claim 4 wherein said voltage sensor is integral with said high tension side of said secondary coil.
- 6. Apparatus for predicting ignition system failures, comprising:
- an ignition coil having a primary coil coupled to a secondary coil;
- a spark plug connected to a high tension side and to a low tension side of said secondary coil and defining a spark gap therebetween;
- an ignition control circuit connected to said primary coil and having an input responsive to a firing command to energize said primary coil to thereby induce a spark voltage in said high tension side of said secondary coil and a corresponding spark in said spark gap, said spark voltage exhibiting a voltage peak having a peak value corresponding to a breakdown voltage of said spark gap; and
- a first computer having an input coupled to said high tension side of said secondary coil for receiving said spark voltage, said first computer comparing a slope of said voltage peak about said peak value with a predefined slope value and producing a prognostic signal corresponding to a predefined ignition system failure mode if said slope of said peak value is less than said predefined slope value.
- 7. The apparatus of claim 6 wherein said first computer further includes means for computing a slope of said voltage peak about said peak value.
- 8. The apparatus of claim 7 wherein said means for computing a slope of said voltage peak about said peak value includes means for computing a first derivative of said voltage peak.
- 9. The apparatus of claim 6 wherein said first computer includes a first memory, said first computer storing in said first memory an error code corresponding to said prognostic signal.
- 10. The apparatus of claim 6 further including a second computer having an input receiving said prognostic signal and a second memory, said second computer storing in said second memory an error code corresponding to said prognostic signal.
- 11. The apparatus of claim 6 further including a voltage sensor associated with said high tension side of said secondary coil, said voltage sensor sensing said spark voltage and providing a spark voltage signal corresponding thereto to said input of said second computer.
- 12. The apparatus of claim 11 wherein said voltage sensor is integral with said high tension side of said secondary coil.
- 13. Apparatus for diagnosing ignition system failures, comprising:
- an ignition coil having a primary coil coupled to a secondary coil;
- a spark plug connected to a high tension side and to a low tension side of said secondary coil and defining a spark gap therebetween;
- an ignition control circuit connected to said primary coil having an input responsive to a firing command to energize said primary coil to thereby induce a spark voltage in said high tension side of said secondary coil and a corresponding spark in said spark gap, said spark voltage exhibiting a voltage peak having a peak value corresponding to a breakdown voltage of said spark gap; and
- a first computer having an input coupled to said high tension side of said secondary coil for receiving said spark voltage, said first computer determining a spark energy of said spark as a function of said peak value of said voltage peak and providing a spark energy correction signal as a function of said spark energy, said ignition control circuit responsive to said spark energy correction signal to alter a spark energy of said spark induced in said spark gap.
- 14. The apparatus of claim 13 wherein said first computer is further operable to determine said spark energy of said spark as a function of a dimension of said spark gap.
- 15. The apparatus of claim 14 wherein said first computer is operable to determine an in-cylinder density value at a time of ignition as a function of said peak value of said voltage peak and a dimension of said spark gap;
- and wherein said first computer is further operable to determine said spark energy as a function of said in-cylinder density value at a time of ignition.
- 16. The apparatus of claim 15 wherein said ignition coil forms part of an internal combustion engine defining a cylinder having said spark plug associated therewith;
- and further including a second computer providing an air-fuel ratio value to said first computer, said air-fuel ratio value corresponding to an air-fuel ratio of fuel provided to said cylinder;
- and wherein said first computer is further operable to determine said spark energy as a function of said air-fuel ratio value.
- 17. The apparatus of claim 13 wherein said spark plug includes a first electrode connected to said high tension side of said secondary coil and a second electrode connected to said low tension side of said secondary coil, said first and second electrodes defining said spark gap therebetween;
- and wherein said ignition control circuit is responsive to said spark energy correction signal to alter the spark energy so as to produce a minimum spark energy necessary to achieve said breakdown voltage and thereby minimize erosion of said first and second spark plug electrodes.
- 18. The apparatus of claim 13 further including a voltage sensor associated with said high tension side of said secondary coil, said voltage sensor sensing said spark voltage and providing a spark voltage signal corresponding thereto to said input of said computer.
- 19. The apparatus of claim 18 wherein said voltage sensor is integral with said high tension side of said secondary coil.
- 20. The apparatus of claim 19 wherein said voltage sensor includes a capacitor having one end connected to said high tension side of said secondary coil and an opposite end providing said spark voltage signal.
CROSS REFERENCE TO RELATED U.S. APPLICATION
This application is a divisional of U.S. application, Ser. No. 08/988,787 filed Dec. 11, 1997 now U.S. Pat. No. 6,006,156 issued Dec. 21, 1999.
US Referenced Citations (6)
Divisions (1)
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Number |
Date |
Country |
Parent |
988787 |
Dec 1997 |
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