EP0709664A1
Expired / Lapsed
EP
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Spectral misfire detection system and method therefor
Assignee: Motorola Solutions Inc
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Filing: 1994-10-31
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Granted: —
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Expires: 2014-10-31
Abstract
Abstract A system, and corresponding method, for detecting the presence of a misfire condition by interpreting spectral activity of a running engine includes a device (309, 313) for measuring a characteristic, preferably an acceleration characteristic indicative of the running engine's performance. A programmable filter (701) dependent on a determined engine speed (335) provides a filtered acceleration signal (703) responsive to an acceleration signal (317) provided by the acceleration measurement device (309, 313). A spectral discrimination device (319), preferably a digital filter, receives the filtered acceleration signal (703) provided by the programmable filter (701). The digital filter (319) provides a normal firing signal (321), corresponding to spectral energy attributable to a portion of the composite signal (317) representative of a normal firing condition in the running engine, and a misfire signal (323), corresponding to spectral energy attributable to another portion of the composite signal (317) representative of a misfiring condition in the running engine. A comparison device (325) provides and indication of a misfire condition (327) when a magnitude of the misfire signal (323) exceeds a magnitude of the normal firing signal (321).
Inventors
- 👤 Donald J. Remboski
- 👤 David Frankowski
- 👤 Kevin J. Bush
- 👤 Steven L. Plee
- 👤 John F. Foley
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-31 16:44
CPC Classifications
G; G01; G01M; G01M15/00; G01M15/04; G01M15/08; G01M15/11; G01M15/12
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
71 words
An apparatus for improving signal fidelity in a misfire detection system of a running engine, the apparatus comprising: acceleration measurement means for providing an acceleration signal indicative of acceleration behavior of the running engine; means for determining the running engine's speed; and filtering means programmable dependent on the running engine's speed, the filtering means for providing a filtered acceleration signal responsive to the acceleration signal provided by the acceleration measurement means.
Claim 2
Dependent Claim
122 words
An apparatus in accordance with claim 1 further comprising: acceleration discrimination means for receiving the filtered acceleration signal provided by said filtering means, and for providing a normal firing signal, corresponding to acceleration behavior attributable to a portion of the composite signal representative of a normal firing condition and, concurrent to the provision of the normal firing signal, for providing a misfire signal, corresponding to acceleration behavior attributable to another portion of the composite signal representative of a misfiring condition; and comparison means for receiving the normal firing signal and the misfire signal, both signals provided by said acceleration discrimination means, and for providing a misfire indication when a magnitude of the misfire signal exceeds a magnitude of the normal firing signal.
Claim 3
Dependent Claim
28 words
An apparatus in accordance with claim 2 wherein said acceleration measurement means comprises means for measuring engine angular acceleration corresponding to an angular displacement of said running engine.
Claim 4
Dependent Claim
24 words
An apparatus in accordance with claim 2 wherein said acceleration measurement means comprises means for measuring acceleration corresponding to vibration of said running engine.
Claim 5
Dependent Claim
29 words
An apparatus in accordance with claim 2 wherein said acceleration measurement means comprises means for measuring an in-cylinder combustion phenomena dependent on an acceleration behavior of said running engine.
Claim 6
Dependent Claim
25 words
An apparatus in accordance with claim 2 further comprising means for shutting off fuel to a cylinder, responsive to the provision of said misfire indication.
Claim 7
Dependent Claim
83 words
An apparatus in accordance with claim 2 wherein said acceleration discrimination means comprises a normal firing acceleration discrimination means responsive to spectral energy attributable to a portion of the composite signal representative of a normal firing condition, and a misfiring signal acceleration discrimination means responsive to spectral energy attributable to a portion of the composite signal representative of a misfiring condition, wherein said misfiring signal acceleration discrimination means is spectrally discriminatory a predetermined fixed spectral distance below said normal firing spectral discrimination means.
Claim 8
Dependent Claim
42 words
An apparatus in accordance with claim 7 wherein said misfiring signal spectral discrimination means comprises multiple spectral discrimination means predominantly responsive to frequencies located at one-half, one, and three-halves cycles/revolution of a predominant spectral location of the normal firing spectral discrimination means.
Claim 9
Dependent Claim
52 words
An apparatus in accordance with claim 8 further comprising: means for providing a synchronization signal representative of said running engine's speed; and wherein said acceleration measurement means of said running engine measures said acceleration at a sample rate responsive to the synchronization signal provided by said means for providing a synchronization signal.
Claim 10
Dependent Claim
19 words
An apparatus in accordance with claim 7 wherein a predominant spectral location of said acceleration discrimination means are tunable.
Claim 11
Dependent Claim
48 words
An apparatus in accordance with claim 10 further comprising: means for providing a synchronization signal representative of said running engine's speed; and wherein the predominant spectral location of said acceleration discrimination means is tuned responsive to the synchronization signal provided by said means for providing a synchronization signal.
Claim 12
Dependent Claim
46 words
An apparatus in accordance with claim 2 wherein said acceleration measurement means measures the acceleration independent of a measurement path length between a motion associated with the acceleration indicative of performance of a combustion process of said running engine and said means for measuring the acceleration.
Claim 13
Dependent Claim
35 words
An apparatus in accordance with claim 2 wherein said acceleration measurement means measures the acceleration independent of a measurement path length between said running engine and said means for measuring in a multiple cylinder engine.
Claim 14
Dependent Claim
32 words
An apparatus in accordance with claim 13 wherein a coupling media used by said acceleration measurement means asserts no load on the engine and has no substantial effect on the acceleration measured.
Claim 15
Independent Claim
145 words
An apparatus for detecting a misfire condition by interpreting acceleration activity of a running engine comprising: acceleration sensing means, coupled to said running engine, for providing a signal representative of said acceleration activity of said running engine and for providing a composite signal in response thereto; acceleration discrimination means for receiving the composite signal provided by said acceleration sensing means, and for providing a normal firing signal, corresponding to acceleration behavior attributable to a portion of the composite signal representative of a normal firing condition, and, concurrent to the provision of the normal firing signal, for providing a misfire signal, corresponding to acceleration behavior attributable to another portion of the composite signal representative of a misfiring condition; and means for providing an indication of a misfire condition when a magnitude of the misfire signal exceeds a magnitude of the firing signal by a predetermined factor.
Claim 16
Dependent Claim
20 words
An apparatus in accordance with claim 15 wherein said acceleration sensing means comprises an accelerometer coupled to said running engine.
Claim 17
Dependent Claim
26 words
An apparatus in accordance with claim 15 wherein said acceleration sensing means comprises means for sensing an acceleration of a crankshaft coupled to said running engine.
Claim 18
Dependent Claim
146 words
An apparatus in accordance with claim 15 wherein said acceleration sensing means further comprises: speed sensing means for providing a synchronization signal representative of said running engine's speed; and wherein said acceleration discrimination means comprises a frequency tunable normal firing acceleration filtering means responsive to acceleration behavior attributable to a portion of the composite signal representative of a normal firing condition, and a frequency tunable misfiring signal acceleration filtering means responsive to acceleration behavior attributable to a portion of the composite signal representative of a misfiring condition, wherein said frequency tunable misfiring signal acceleration filtering means is spectrally located a predetermined fixed spectral distance below said frequency tunable normal firing acceleration filtering means and wherein both said frequency tunable normal firing acceleration filtering means, and said frequency tunable misfiring acceleration filtering means are spectrally tuned responsive to said synchronization signal provided by said speed sensing means.
Claim 19
Dependent Claim
45 words
An apparatus in accordance with claim 18 wherein said frequency tunable misfiring signal acceleration filtering means comprises multiple acceleration filtering means predominantly responsive to acceleration spectra located at one-half, one, and three-halves cycles/revolution of a predominant spectral location of the normal firing spectral discrimination means.
Claim 20
Independent Claim
180 words
A method for detecting a misfire condition by interpreting acceleration of a running engine comprising the steps of: providing an acceleration signal indicative of acceleration behavior of the running engine; determining a speed of the running engine; providing a filtered acceleration signal responsive to the step of providing an acceleration signal dependent on the speed of the running engine determined on the step of determining; spectrally discriminating the composite signal provided in said step of measuring, and for providing a normal firing signal corresponding to spectral energy attributable to a portion of the composite signal representative of a normal firing condition in said running engine, and, concurrent to the provision of the normal firing signal, for providing a misfire signal, corresponding to spectral energy attributable to another portion of the composite signal representative of a misfiring condition in said running engine; and comparing the normal firing signal and the misfire signal, both signals provided in said step of measuring, and for providing a misfire indication when a magnitude of the misfire signal exceeds a magnitude of the normal firing signal.
Claim 21
Independent Claim
183 words
An apparatus for detecting a misfire condition by interpreting spectral activity of a running engine comprising: means for measuring a characteristic, indicative of performance of a combustion process of said running engine, and for providing a composite spectral signal representative of the performance of said combustion process; noise spectral discrimination means for receiving the composite spectral signal provided by said means for measuring a characteristic, and for providing a noise filtered signal absent of a predetermined noise component of the composite spectral signal; spectral discrimination means for receiving the noise filtered signal provided by said noise spectral discrimination means, and for providing a normal firing signal, corresponding to spectral energy attributable to a portion of the composite signal representative of a normal firing condition in said running engine, and for providing a misfire signal, corresponding to spectral energy attributable to another portion of the composite signal representative of a misfiring condition in said running engine; and means for providing an indication of a misfire condition when a magnitude of the misfire signal exceeds a magnitude of the firing signal by a predetermined factor.
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