US5212947A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Failure-detecting device for air-fuel ratio sensors of internal combustion engines
Assignee: Honda Motor Co Ltd
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Filing: 1992-03-06
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Granted: 1993-05-25
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Expires: 2012-03-06
Abstract
Abstract A failure-detecting device detects failure of an air-fuel ratio sensor arranged downstream of a three-way catalyst in an exhaust passage of an internal combustion engine. The air-fuel ratio of an air-fuel mixture supplied to the engine is perturbed with a predetermined repetition period and by a predetermined amplitude. There is detected an amount of change in an output from the air-fuel ratio sensor responsive to the perturbed air-fuel ratio. Failure of the air-fuel ratio sensor is detected based on the amount of change in the output from the air-fuel ratio sensor.
Inventors
- 👤 Sachito Fujimoto
- 👤 Kojiro Tsutsumi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 12:05
CPC Classifications
F; F02; F02D; F02D41/00; F02D41/02; F02D41/14; F02D41/1438; F02D41/1493; F02D41/1495; Y; Y02; Y02T; Y02T10/00; Y02T10/10; Y02T10/12
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
136 words
A failure-detecting device for an air-fuel ratio sensor of an internal combustion engine including an exhaust passage, and a three-way catalyst arranged in said exhaust passage, said air-fuel ratio sensor being arranged downstream of said three-way catalyst in said exhaust passage, said failure-detecting device comprising: air-fuel ratio-perturbing means for changing the air-fuel ratio of an air-fuel mixture supplied to said engine with a predetermined repetition period and by a predetermined amplitude; air-fuel ratio variation-detecting means for detecting an amount of change in an output from said air-fuel ratio sensor responsive to the air-fuel ratio of said air-fuel mixture perturbed by said air-fuel ratio-perturbing means; and failure-detecting means for detecting failure of said air-fuel ratio sensor based on the amount of change in said output from said air-fuel ratio sensor detected by said air-fuel ratio variation-detecting means.
Claim 2
Dependent Claim
136 words
A failure-detecting device for an air-fuel ratio sensor of an internal combustion engine including an exhaust passage, and a three-way catalyst arranged in said exhaust passage, said air-fuel ratio sensor being arranged downstream of said three-way catalyst in said exhaust passage, said failure-detecting device comprising: air-fuel ratio-perturbing means for changing the air-fuel ratio of an air-fuel mixture supplied to said engine with a predetermined repetition period and by a predetermined amplitude; air-fuel ratio variation-detecting means for detecting an amount of change in an output from said air-fuel ratio sensor responsive to the air-fuel ratio of said air-fuel mixture perturbed by said air-fuel ratio-perturbing means; and failure-detecting means for detecting failure of said air-fuel ratio sensor based on the amount of change in said output from said air-fuel ratio sensor detected by said air-fuel ratio variation-detecting means.
Claim 3
Dependent Claim
37 words
A failure-detecting device for an air-fuel ratio sensor according to claim 1, wherein said air-fuel ratio variation-detecting means detects the amount of change in said output from said air-fuel ratio sensor occurring within a predetermined time period.
Claim 4
Dependent Claim
54 words
A failure-detecting device for an air-fuel ratio sensor according to claim 2, wherein said failure-detecting means determines that there is a possibility that there is failure in said air-fuel ratio sensor when the detected amount of change in said output from said air-fuel ratio sensor is equal to or smaller than a predetermined value.
Claim 5
Dependent Claim
98 words
A failure-detecting device for an air-fuel ratio sensor according to claim 3, wherein said failure-detecting means includes sensor output-determining means for determining whether or not said output from said air-fuel ratio sensor falls within a predetermined range defined by predetermined upper and lower limit values, said failure-detecting means determining that there is failure in said air-fuel ratio sensor when the detected amount of change in said output from said air-fuel ratio sensor is equal to or smaller than said predetermfined value and at the same time said output from said air-fuel ratio sensor falls outside said predetermined range.
Claim 6
Dependent Claim
43 words
A failure-detecting device for an air-fuel ratio sensor according to claim 4, wherein said failure-detecting means determines that there is a disconnection in said air-fuel ratio sensor when said output from said air-fuel ratio sensor is higher than said predetermined upper limit value.
Claim 7
Dependent Claim
52 words
A failure-detecting device for an air-fuel ratio sensor according to claim 5, wherein said failure-detecting means finally determines that there is a disconnection in said air-fuel ratio sensor when said output from said air-fuel ratio sensor has continued to be higher than said predetermined upper limit value over a predetermined time period.
Claim 8
Dependent Claim
44 words
A failure-detecting device for an air-fuel ratio sensor according to claim 4, wherein said failure-detecting means determines that there is a short circuit in said air-fuel ratio sensor when said output from said air-fuel ratio sensor is lower than said predetermined lower limit value.
Claim 9
Dependent Claim
52 words
A failure-detecting device for an air-fuel ratio sensor according to claim 7, wherein said failure-detecting means finally determines that there is a short-circuit in said air-fuel ratio sensor when said output from said air-fuel ratio sensor has continued to be lower than said predetermined lower limit value over a predetermined time period.
Claim 10
Dependent Claim
37 words
A failure-detecting device for an air-fuel ratio sensor according to claim 1, wherein said air-fuel ratio perturbing means changes a value of an air-fuel ratio correction value for correcting an amount of fuel supplied to said engine.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-05-24 | 1996-11-23 | 1997-05-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-05-24 | 2000-11-23 | 2001-05-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-05-24 | 2004-11-23 | 2005-05-25 | $7700.00 | Window Closed / Lapsed |