US5041980A
Expired / Lapsed
US
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Method and apparatus for producing fault signals responsive to malfunctions in individual engine cylinders
Assignee: Caterpillar Inc
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Filing: 1990-06-04
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Granted: 1991-08-20
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Expires: 2010-06-04
Abstract
Abstract Dynamic engine diagnostic devices are useful for detecting engine faults such as a misfiring cylinder during normal engine operation. Identification of the particular cylinder having the fault enables repairs to be made more efficiently. In the subject application, an apparatus is provided for detecting malfunctions in individual cylinders of an internal combustion engine having a rotating member driven by a plurality of cylinders. The apparatus includes a sensor for measuring the time between successive angular positions as the member rotates through at least one engine cycle and producing a plurality of period signals responsive respectively to the measured time intervals. Each engine cylinder has an equal number of the angular positions associated therewith, and the member makes one rotation per engine cycle. A deviation circuit receives the period signals and produces a deviation signal for each engine cylinder. Each deviation signal is responsive to a difference between period signals of a respective cylinder. An averaging circuit receives the deviation signals and produces an average signal responsive to an average of the deviation signals. A comparator receives the deviation and average signals, compares each deviation signal to the average signal, and produces respective fault signals in response to individual deviation signals differing from the average signal by more than a first threshold.
Inventors
- 👤 James B. Maddock
- 👤 Bradley W. Harrell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 00:25
CPC Classifications
G; G01; G01M; G01M15/00; G01M15/04; G01M15/11
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
175 words
An apparatus for detecting malfunctions in individual cylinders of an internal combustion engine having a rotating member driven by a plurality of cylinders, comprising: sensor means for measuring the time between successive angular positions as said member rotates through at least one engine cycle and producing a plurality of period signals responsive respectively to said measured time intervals, wherein each engine cylinder has an equal number of said angular positions associated therewith and said member makes at least one rotation per engine cycle; deviation means for receiving said period signals and producing a deviation signal for each engine cylinder, said deviation signal being responsive to a difference between said period signals of a respective cylinder; average means for receiving said deviation signals and producing an average signal responsive to an average of said deviation signals; and comparator means for receiving said deviation and average signals, comparing each deviation signal to said average signal, and producing respective fault signals in response to individual deviation signals differing from said average signal by more than a first threshold.
Claim 2
Independent Claim
175 words
An apparatus for detecting malfunctions in individual cylinders of an internal combustion engine having a rotating member driven by a plurality of cylinders, comprising: sensor means for measuring the time between successive angular positions as said member rotates through at least one engine cycle and producing a plurality of period signals responsive respectively to said measured time intervals, wherein each engine cylinder has an equal number of said angular positions associated therewith and said member makes at least one rotation per engine cycle; deviation means for receiving said period signals and producing a deviation signal for each engine cylinder, said deviation signal being responsive to a difference between said period signals of a respective cylinder; average means for receiving said deviation signals and producing an average signal responsive to an average of said deviation signals; and comparator means for receiving said deviation and average signals, comparing each deviation signal to said average signal, and producing respective fault signals in response to individual deviation signals differing from said average signal by more than a first threshold.
Claim 3
Dependent Claim
30 words
An apparatus as set forth in claim 1 wherein said deviation means produces said deviation signal in response to the maximum decrease between period signals for a respective engine cylinder.
Claim 4
Dependent Claim
30 words
An apparatus as set forth in claim 2 wherein a negative deviation signal is produced in response to said period signals associated with a respective cylinder successively increasing in magnitude.
Claim 5
Dependent Claim
38 words
An apparatus as set forth in claim 1 wherein said comparator means produces said fault signal for a cylinder in response to said deviation signal being less than than said average signal by at least said first threshold.
Claim 6
Dependent Claim
22 words
An apparatus as set forth in claim 4 wherein said first threshold is equal to one-half the magnitude of said average signal.
Claim 7
Dependent Claim
34 words
An apparatus as set forth in claim 1 wherein said comparator means produces said fault signals in response to respective deviation signals being less than a second threshold if said average signal is negative.
Claim 8
Dependent Claim
60 words
An apparatus as set forth in claim 1 including a means for receiving said fault signals, producing a plurality of summed fault signals, each of said summed fault signals being responsive to a sum of said fault signals for a respective cylinder over time, and producing failed cylinder signals responsive respectively to individual summed fault signals exceeding a third threshold.
Claim 9
Dependent Claim
36 words
An apparatus as set forth in claim 7 wherein said failed cylinder signal is produced in response to the the number of fault signals produced for a respective cylinder during a preselected number of engine cycles.
Claim 10
Independent Claim
219 words
An apparatus for detecting malfunctions in individual cylinders of an internal combustion engine having a rotating member driven by a plurality of said cylinders, comprising: sensor means for measuring the time between successive angular positions as said member rotates through at least one engine cycle and producing a plurality of period signals responsive respectively to said measured time intervals, wherein each engine cylinder has an equal number of said angular positions associated therewith and said member makes at least one rotation per engine cycle; deviation means for receiving said period signals and producing a deviation signal for each engine cylinder, said deviation signal being responsive to a difference between said period signals of a respective cylinder; average means for receiving said deviation signals and producing an average signal responsive to an average of said deviation signals; and comparator means for receiving said deviation and average signals, determining if said average signal is less than, equal to, or greater than zero, producing respective fault signals in response to said deviation signals being less than a third preselected threshold if said average signal is less than zero, and producing respective fault signals in response to individual deviation signals being less than said average signal by more than a first threshold if said average signal is greater than or equal to zero.
Claim 11
Independent Claim
219 words
An apparatus for detecting malfunctions in individual cylinders of an internal combustion engine having a rotating member driven by a plurality of said cylinders, comprising: sensor means for measuring the time between successive angular positions as said member rotates through at least one engine cycle and producing a plurality of period signals responsive respectively to said measured time intervals, wherein each engine cylinder has an equal number of said angular positions associated therewith and said member makes at least one rotation per engine cycle; deviation means for receiving said period signals and producing a deviation signal for each engine cylinder, said deviation signal being responsive to a difference between said period signals of a respective cylinder; average means for receiving said deviation signals and producing an average signal responsive to an average of said deviation signals; and comparator means for receiving said deviation and average signals, determining if said average signal is less than, equal to, or greater than zero, producing respective fault signals in response to said deviation signals being less than a third preselected threshold if said average signal is less than zero, and producing respective fault signals in response to individual deviation signals being less than said average signal by more than a first threshold if said average signal is greater than or equal to zero.
Claim 12
Independent Claim
149 words
A method for detecting malfunctions in individual cylinders of an internal combustion engine having rotating member driven by a plurality of cylinders, comprising the steps of: sensing the time between successive angular positions as said member rotates through at least one engine cycle and producing a plurality of period signals responsive respectively to said measured time intervals, wherein each engine cylinder has an equal number of said angular positions associated therewith and said member makes at least one rotation per engine cycle; producing a deviation signal for each engine cylinder, said deviation signal being responsive to a difference between said period signals of a respective cylinder; producing an average signal responsive to an average of said deviation signals; and comparing each deviation signal to said average signal and producing respective fault signals in response to individual deviation signals differing from said average signal by more than a first threshold.
Claim 13
Independent Claim
149 words
A method for detecting malfunctions in individual cylinders of an internal combustion engine having rotating member driven by a plurality of cylinders, comprising the steps of: sensing the time between successive angular positions as said member rotates through at least one engine cycle and producing a plurality of period signals responsive respectively to said measured time intervals, wherein each engine cylinder has an equal number of said angular positions associated therewith and said member makes at least one rotation per engine cycle; producing a deviation signal for each engine cylinder, said deviation signal being responsive to a difference between said period signals of a respective cylinder; producing an average signal responsive to an average of said deviation signals; and comparing each deviation signal to said average signal and producing respective fault signals in response to individual deviation signals differing from said average signal by more than a first threshold.
Claim 14
Dependent Claim
28 words
A method as set forth in claim 10 wherein said deviation signal is produced in response to the maximum decrease between period signals for a respective engine cylinder.
Claim 15
Dependent Claim
29 words
A method as set forth in claim 11 wherein a negative deviation signal is produced in response to said period signals for a respective cylinder successively increasing in magnitude.
Claim 16
Dependent Claim
37 words
A method as set forth in claim 10 wherein said fault signal for a cylinder is produced in response to said deviation signal for that cylinder being less than than said average signal by said first threshold.
Claim 17
Dependent Claim
22 words
A method as set forth in claim 13 wherein said first threshold is equal to one-half the magnitude of said average signal.
Claim 18
Dependent Claim
32 words
A method as set forth in claim 10 wherein said fault signals are produced in response to respective deviation signals being less than a third threshold when said average signal is negative.
Claim 19
Dependent Claim
52 words
A method as set forth in claim 10 further including the steps of: producing a plurality of summed fault signals, each being responsive to a sum of said fault signals for a respective cylinder over time; and producing failed cylinder signals responsive respectively to individual summed fault signals exceeding a third threshold.
Claim 20
Dependent Claim
36 words
A method as set forth in claim 16 wherein said failed cylinder signal is produced in response to the the number of fault signals produced for a respective cylinder during a preselected number of engine cycles.
Claim 21
Independent Claim
174 words
An apparatus for detecting malfunctions in individual cylinders of an internal combustion engine having a rotating member driven by a plurality of cylinders, comprising: sensor means for measuring the time between successive angular positions as said member rotates through at least one engine cycle and for producing a plurality of period signals responsive respectively to said measured time intervals, wherein each engine cylinder has an equal number of said angular position associated therewith and the member makes at least one rotation per engine cycle; deviation means for receiving said period signals and producing a deviation signal for each engine cylinder in response to the maximum decrease between period signals for a respective engine cylinder; average means for receiving said deviation signals and producing an average signal responsive to an average of said deviation signals; and comparator means for receiving said average and deviation signals, comparing each deviation signal to said average signal, and producing respective fault signals in response to individual deviation signals differing from said average signal by more than a first threshold.
Claim 22
Independent Claim
174 words
An apparatus for detecting malfunctions in individual cylinders of an internal combustion engine having a rotating member driven by a plurality of cylinders, comprising: sensor means for measuring the time between successive angular positions as said member rotates through at least one engine cycle and for producing a plurality of period signals responsive respectively to said measured time intervals, wherein each engine cylinder has an equal number of said angular position associated therewith and the member makes at least one rotation per engine cycle; deviation means for receiving said period signals and producing a deviation signal for each engine cylinder in response to the maximum decrease between period signals for a respective engine cylinder; average means for receiving said deviation signals and producing an average signal responsive to an average of said deviation signals; and comparator means for receiving said average and deviation signals, comparing each deviation signal to said average signal, and producing respective fault signals in response to individual deviation signals differing from said average signal by more than a first threshold.
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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) | 1994-08-19 | 1995-02-18 | 1995-08-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-08-19 | 1999-02-18 | 1999-08-20 | $3760.00 | Window Closed / Lapsed |
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