US5337558A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Engine exhaust purification system
Assignee: Mazda Motor Corp
•
Filing: 1993-03-16
•
Granted: 1994-08-16
•
Expires: 2013-03-16
Abstract
Abstract An engine exhaust purification system is provided with a catalyst in an exhaust line, and oxygen sensors disposed in the exhaust line upstream and downstream from the catalyst, respectively. Deterioration of the catalyst is judged based on a frequency ratio of reversal of an output from the downstream oxygen sensor with respect to a threshold value to an output from the upstream oxygen sensor with respect to a threshold value. The threshold value of the deteriorated oxygen sensor is changed so as to vary the frequency ratio of reversal.
Inventors
- 👤 Kazunari Komatsu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 20:21
CPC Classifications
F; F01; F01N; F01N11/00; F01N11/007; F02; F02D; F02D41/00; F02D41/02; F02D41/021; F02D41/0235; F02D41/14; F02D41/1438; F02D41/1439; F02D41/1441; F02D41/1473; F02D41/1474; F02D41/1493; F02D41/1495; F01N2550/00; F01N2550/02; F02D41/1401; Y; Y02; Y02T; Y02T10/00; Y02T10/10; Y02T10/40
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
132 words
An engine exhaust purification system, for an internal combustion engine, having an engine exhaust purifying catalyst in an exhaust line, said engine exhaust purification system comprising: an upstream oxygen sensor disposed in the exhaust line upstream from the engine exhaust purifying catalyst; a downstream oxygen sensor disposed in the exhaust line downstream from the engine exhaust purifying catalyst; and judging means for detecting an output ratio of an output from said upstream oxygen sensor to an output from said downstream oxygen sensor, for judging a deterioration of said catalyst based on said output ratio, for detecting a deterioration of each of said upstream and downstream oxygen sensors based on said outputs, respectively, and for correcting said output ratio when detecting a deterioration at least one of said upstream and downstream oxygen sensors.
Claim 2
Dependent Claim
132 words
An engine exhaust purification system, for an internal combustion engine, having an engine exhaust purifying catalyst in an exhaust line, said engine exhaust purification system comprising: an upstream oxygen sensor disposed in the exhaust line upstream from the engine exhaust purifying catalyst; a downstream oxygen sensor disposed in the exhaust line downstream from the engine exhaust purifying catalyst; and judging means for detecting an output ratio of an output from said upstream oxygen sensor to an output from said downstream oxygen sensor, for judging a deterioration of said catalyst based on said output ratio, for detecting a deterioration of each of said upstream and downstream oxygen sensors based on said outputs, respectively, and for correcting said output ratio when detecting a deterioration at least one of said upstream and downstream oxygen sensors.
Claim 3
Dependent Claim
58 words
An engine exhaust purification system as defined in claim 1, wherein said judging means calculates, as said output ratio, a frequency ratio of reverse of an output from said upstream oxygen sensor with respect to a first preselected threshold value to reverse of an output from said downstream oxygen sensor with respect to a second preselected threshold value.
Claim 4
Dependent Claim
49 words
An engine exhaust purification system as defined in claim 2, wherein said judging means changes said preselected threshold value of one of said upstream and downstream oxygen sensors according to a deterioration of said one of said upstream and downstream oxygen sensors, thereby correcting said frequency ratio of reverse.
Claim 5
Dependent Claim
40 words
An engine exhaust purification system as defined in claim 2, wherein said judging means changes said preselected threshold value of said downstream oxygen sensor according to a deterioration of said downstream oxygen sensor, thereby correcting said frequency ratio of reverse.
Claim 6
Dependent Claim
54 words
An engine exhaust purification system as defined in claim 2, wherein said judging means changes said preselected threshold value of said downstream oxygen sensor according to a deterioration of said downstream oxygen sensor so as to provide an air-fuel ratio by which a fuel mixture is enriched, thereby correcting said frequency ratio of reverse.
Claim 7
Dependent Claim
35 words
An engine exhaust purification system as defined in claim 2, wherein said judging means detects a deterioration of each said oxygen sensor based on a voltage drop of an output of each said oxygen sensor.
Claim 8
Dependent Claim
33 words
An engine exhaust purification system as defined in claim 2, wherein said judging means detects a deterioration of each said oxygen sensor based on a delay in response of each said oxygen sensor.
References Cited (Backward Citations)
JPS6397852A
Cited
US5099647A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-08-15 | 1998-02-14 | 1998-08-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-08-15 | 2002-02-14 | 2002-08-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-08-15 | 2006-02-14 | 2006-08-16 | $7700.00 | Window Closed / Lapsed |