Patent US5392641A successfully refreshed from Google Patents.
US5392641A
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Ionization misfire detection apparatus and method for an internal combustion engine
Assignee: FCA US LLC
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Filing: 1993-03-08
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Granted: 1995-02-28
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Expires: 2013-03-08
Abstract
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.
Inventors
- 👤 Jay C. McCombie
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 12:59
CPC Classifications
F; F02; F02P; F02P11/00; F02P11/06; F02P17/00; F02P17/12; F02P2017/006; F02P2017/125; F02P2017/128
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
78 words
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.
Claim 2
Independent Claim
78 words
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.
Claim 3
Dependent Claim
21 words
A method as set forth in claim 1 including the step of initializing predetermined variables prior to said step of determining.
Claim 4
Dependent Claim
23 words
A method as set forth in claim 1 wherein said step of determining includes determining if ionization data is ready to be processed.
Claim 5
Independent Claim
92 words
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.
Claim 6
Independent Claim
92 words
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.
Claim 7
Dependent Claim
20 words
A method as set forth in claim 4 wherein said step of making comprises reading an ionization value for cylinders.
Claim 8
Independent Claim
109 words
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.
Claim 9
Independent Claim
109 words
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.
Claim 10
Dependent Claim
38 words
A method as set forth in claim 6 including the step of determining if 200 engine revolutions have been completed or if 1000 engine revolutions have been completed if the ionization data is not ready to be processed.
Claim 11
Independent Claim
25 words
A method as set forth in claims 6 including the step of calculating engine RPM prior to said determining whether predetermined conditions have been met.
Claim 12
Independent Claim
117 words
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.
Claim 13
Independent Claim
117 words
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.
Claim 14
Dependent Claim
36 words
A method as set forth in claim 9 wherein said step of determining the current load factor on the engine comprises finding a shorted spark plug ionization threshold and finding a minimum ionization for combustion threshold.
Claim 15
Dependent Claim
35 words
A method as set forth in claim 10 wherein said step of determining the current load factor on the engine further comprises calculating a cylinder identification and then proceeding to a corresponding cylinder service routine.
Claim 16
Dependent Claim
32 words
A method as set forth in claim 11 including the step of calculating a drift term whereby minor parallel d.c. current or circuit drift are compensated for after said step of proceeding.
Claim 17
Dependent Claim
26 words
A method as set forth in claim 12 wherein said step of determining if misfire has occurred comprises evaluating a predetermined cylinder for a possible misfire.
Claim 18
Dependent Claim
31 words
A method as set forth in claim 13 wherein said step of determining if misfire has occurred further comprises determining whether a combustion was detected based on evaluation of predetermined cylinders.
Claim 19
Independent Claim
160 words
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.
Claim 20
Independent Claim
160 words
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.
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1998-02-27 | 1998-08-29 | 1999-02-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-02-27 | 2002-08-29 | 2003-02-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-02-27 | 2006-08-29 | 2007-02-28 | $7700.00 | Window Closed / Lapsed |