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US5044196A
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Method and apparatus for detecting deterioration of a hot-wire type sucked air flow quantity-detecting device for an engine
Assignee: Hitachi Unisia Automotive Ltd
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Filing: 1990-06-20
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Granted: 1991-09-03
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Expires: 2010-06-20
Abstract
Abstract The present invention relates to a method and apparatus for detecting deterioration of a hot-wire type sucked air flow quantity-detecting device of an engine, in which the change ratio of the output voltage of the hot-wire type sucked air flow quantity-detecting device is measured when the output voltage of the sucked air flow quantity-detecting device is to be changed while the engine is in the substantially non-revolving state, and deterioration is judged by comparing the measured change ratio with a predetermined value, whereby it is possible to exchange parts promptly just in time and prevent degradation of the exhaust gas-purging performance of a vehicle.
Inventors
- 👤 Naoki Tomisawa
- 👤 Hiroshi Okada
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 20:13
CPC Classifications
G; G01; G01F; G01F1/00; G01F1/68; G01F1/696; F; F02; F02D; F02D41/00; F02D41/02; F02D41/18; F02D41/187; G01F25/00; G01F25/10
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
113 words
A method for detecting deterioration of a hot-wire type sucked air flow quantity-detecting device for detecting the flow quantity of air sucked in an engine, which comprises the step of emitting a diagnosis instruction when the output voltage of the hot-wire type sucked air flow quantity-detecting device is to be changed while the engine is in the substantially non-revolving state, the step of measuring the ratio of the change of the output voltage of the sucked air flow quantity-detecting device on receipt of the instruction from a diagnosis-instructing unit, and the step of judging deterioration when the change ratio measured by an output voltage change ratio-measuring unit is smaller than a predetermined value.
Claim 2
Independent Claim
113 words
A method for detecting deterioration of a hot-wire type sucked air flow quantity-detecting device for detecting the flow quantity of air sucked in an engine, which comprises the step of emitting a diagnosis instruction when the output voltage of the hot-wire type sucked air flow quantity-detecting device is to be changed while the engine is in the substantially non-revolving state, the step of measuring the ratio of the change of the output voltage of the sucked air flow quantity-detecting device on receipt of the instruction from a diagnosis-instructing unit, and the step of judging deterioration when the change ratio measured by an output voltage change ratio-measuring unit is smaller than a predetermined value.
Claim 3
Independent Claim
114 words
An apparatus for detecting deterioration of a hot-wire type sucked air flow quantity-detecting device for detecting the flow quantity of air sucked in an engine, which comprises diagnosis-instructing means for emitting a diagnosis instruction when the output voltage of the hot-wire type sucked air flow quantity-detecting device is to be changed while the engine is in the substantially non-revolving state, output voltage change ratio-measuring means for measuring the change ratio of the output voltage of the sucked air flow quantity-detecting device on receipt of the instruction from the diagnosis-instructing means, and deterioration-judging means for judging deterioration when the change ratio measured by the output voltage change ratio-measuring means is smaller than a predetermined value.
Claim 4
Independent Claim
114 words
An apparatus for detecting deterioration of a hot-wire type sucked air flow quantity-detecting device for detecting the flow quantity of air sucked in an engine, which comprises diagnosis-instructing means for emitting a diagnosis instruction when the output voltage of the hot-wire type sucked air flow quantity-detecting device is to be changed while the engine is in the substantially non-revolving state, output voltage change ratio-measuring means for measuring the change ratio of the output voltage of the sucked air flow quantity-detecting device on receipt of the instruction from the diagnosis-instructing means, and deterioration-judging means for judging deterioration when the change ratio measured by the output voltage change ratio-measuring means is smaller than a predetermined value.
Claim 5
Dependent Claim
51 words
An apparatus for detecting deterioration of a hot-wire type sucked air flow quantity-detection device of an engine according to claim 2, wherein the time of emitting the instruction by the diagnosis-instructing means is the time when the start of application of electricity to the sucked air flow quantity-detecting device is detected.
Claim 6
Dependent Claim
51 words
An apparatus for detecting deterioration of a hot-wire type sucked air flow quantity-detecting device of an engine according to claim 2, wherein the time of emitting the instruction by the diagnosis-instructing means is the time when the stop of application of electricity to the sucked air flow quantity-detecting device is detected.
Claim 7
Dependent Claim
42 words
An apparatus for detecting deterioration of a hot-wire type sucked air flow quantity-detecting device of an engine according to claim 2, wherein the time of emitting the instruction by the diagnosis-instructing means is the time when stalling of the engine is detected.
References Cited (Backward Citations)
JPS55124017A
Cited
JPS60240840A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-09-02 | 1995-03-04 | 1995-09-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-09-02 | 1999-03-04 | 1999-09-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-09-02 | 2003-03-04 | 2003-09-03 | $7700.00 | Window Closed / Lapsed |