Patent US5673555A successfully refreshed from Google Patents.
US5673555A
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Method for checking the efficiency of a catalytic converter
Assignee: Siemens AG
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Filing: 1995-11-27
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Granted: 1997-10-07
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Expires: 2015-11-27
Abstract
Abstract A method is provided for checking the efficiency of a catalytic converter with an oxygen probe upstream of the catalytic converter and of an oxygen probe downstream of the catalytic converter. A ratio of times in which the oxygen probe downstream of the catalytic converter and the oxygen probe upstream of the catalytic converter indicate a rich or a lean mixture value is formed. The catalytic converter has a sufficient efficiency if the value of the smaller amount of the ratio values is lower than a predeterminable limit value.
Inventors
- 👤 Erwin Achleitner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 06:43
CPC Classifications
F; F02; F02D; F02D41/00; F02D41/02; F02D41/14; F02D41/1438; F02D41/1439; F02D41/1441; F01; F01N; F01N13/00; F01N11/00; F01N11/007; F01N2550/00; F01N2550/02; F01N2900/00; F01N2900/04; F01N2900/0422; Y; Y02; Y02T; Y02T10/00; Y02T10/10; Y02T10/40
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
116 words
A method for checking the efficiency of a catalytic converter having an oxygen probe upstream and an oxygen probe downstream of the catalytic converter, which comprises: forming a ratio of times during which an oxygen probe downstream of a catalytic converter and an oxygen probe upstream of the catalytic converter indicate a rich mixture during a test period; forming a ratio of times during which the oxygen probe downstream of the catalytic converter and the oxygen probe upstream of the catalytic converter indicate a lean mixture during a test period; and indicating that an efficiency of the catalytic converter is sufficient if the smaller value of the two ratios is lower than a predeterminable limit value.
Claim 2
Independent Claim
116 words
A method for checking the efficiency of a catalytic converter having an oxygen probe upstream and an oxygen probe downstream of the catalytic converter, which comprises: forming a ratio of times during which an oxygen probe downstream of a catalytic converter and an oxygen probe upstream of the catalytic converter indicate a rich mixture during a test period; forming a ratio of times during which the oxygen probe downstream of the catalytic converter and the oxygen probe upstream of the catalytic converter indicate a lean mixture during a test period; and indicating that an efficiency of the catalytic converter is sufficient if the smaller value of the two ratios is lower than a predeterminable limit value.
Claim 3
Dependent Claim
27 words
The method according to claim 1, which comprises conducting the catalytic converter efficiency check only when the internal combustion engine is in an approximately steady-state operating state.
Claim 4
Dependent Claim
28 words
The method according to claim 1, which comprises averaging the smaller value of the ratios of the lean and rich times before a comparison with the limit value.
Claim 5
Dependent Claim
20 words
The method according to claim 1, which comprises supplying a result of the catalytic converter efficiency check for statistical evaluation.
Claim 6
Dependent Claim
29 words
The method according to claim 1, which comprises setting the limit value of the ratio times in dependence on a load and a speed of the internal combustion engine.
References Cited (Backward Citations)
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Cited
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EP0536789A2
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-10-06 | 2001-04-07 | 2001-10-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-10-06 | 2005-04-07 | 2005-10-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-10-06 | 2009-04-07 | 2009-10-07 | $7700.00 | Window Closed / Lapsed |