US5661971A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for reducing pollutants in the exhaust gas of a multi-cylinder internal combustion engine
Assignee: Volkswagen AG
•
Filing: 1995-11-17
•
Granted: 1997-09-02
•
Expires: 2015-11-17
Abstract
Abstract In the embodiments described in the specification pollutants in the exhaust gas of a multi-cylinder internal combustion engine of a motor vehicle having an exhaust-gas purification device containing a catalyst in the exhaust line are reduced by controlling The air/fuel ratio supplied to the cylinders of the internal combustion engine in such a way that at least one of the engine cylinders is operated with a lean air/fuel ratio and the remaining cylinders are operated with a rich air/fuel ratio while a lambda value of approximately one is maintained in the overall exhaust flow from all the cylinders. In addition to rapid heating of the catalyst in the exhaust-gas purification device and compensation for a relatively low storage capacity of the catalyst, this arrangement also reduces the quantity of untreated exhaust upstream of the catalyst.
Inventors
- 👤 Uwe Waschatz
- 👤 Wolfgang Wehling
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 15:47
CPC Classifications
F; F02; F02D; F02D41/00; F02D41/008; F01; F01N; F01N3/00; F01N3/08; F01N3/10; F01N3/18; F01N3/20; F01N3/2006; F02D41/02; F02D41/021; F02D41/0235; F02D41/024; F02D41/025; F02D41/14; F02D41/1438; F02D41/1473; F02D41/1475; F01N2430/00; F01N2430/06; F02D41/1401; F02D41/1408; Y; Y02; Y02A; Y02A50/00; Y02A50/20; Y02T; Y02T10/00; Y02T10/10; Y02T10/12
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
97 words
A method for reducing pollutants in the exhaust gas of a multi-cylinder internal combustion engine of a motor vehicle having an exhaust gas purification device located in an exhaust line of the internal combustion engine comprising supplying at least one cylinder with a relatively lean air/fuel ratio and supplying the remaining cylinders with a relatively rich air/fuel ratio while maintaining the combined air/fuel ratio for all of the cylinders of the internal combustion engine at a level which produces a lambda value of approximately one in the overall exhaust flow from all the cylinders of the engine.
Claim 2
Independent Claim
97 words
A method for reducing pollutants in the exhaust gas of a multi-cylinder internal combustion engine of a motor vehicle having an exhaust gas purification device located in an exhaust line of the internal combustion engine comprising supplying at least one cylinder with a relatively lean air/fuel ratio and supplying the remaining cylinders with a relatively rich air/fuel ratio while maintaining the combined air/fuel ratio for all of the cylinders of the internal combustion engine at a level which produces a lambda value of approximately one in the overall exhaust flow from all the cylinders of the engine.
Claim 3
Dependent Claim
26 words
A method according to claim 1, including the step of supplying at least one of the cylinders alternately with a rich and a lean air/fuel ratio.
Claim 4
Dependent Claim
35 words
A method according to claim 1 including the step of controlling the distribution of the rich and the lean air/fuel ratios among the cylinders as a function of operating conditions of the internal combustion engine.
Claim 5
Dependent Claim
32 words
A method according to claim 1, including the step of controlling the magnitude of the air/fuel ratios of the individual cylinders as a function of operating conditions of the internal combustion engine.
Claim 6
Dependent Claim
32 words
A method according to claim 1, including the step of changing the air/fuel ratio supplied to the cylinders between a lean air/fuel ratio and a rich air/fuel ratio at the ignition frequency.
Claim 7
Dependent Claim
87 words
A method according to claim 1 including the steps of operating at least one cylinder with a lean air/fuel ratio and the remaining cylinders with a rich air/fuel ratio when the temperature of either the internal combustion engine or of the exhaust-gas purification device is below a threshold value and operating the internal combustion engine with conventional closed-loop lambda control to maintain lambda approximately equal to one when the temperature of either the internal combustion engine or of the exhaust-gas purification device is above a threshold value.
Claim 8
Dependent Claim
41 words
A method according to claim 6 wherein at least one cylinder is operated with a lean air/fuel ratio and the remaining cylinders are operated with a rich air/fuel ratio when the temperature is below the threshold value for a predetermined time.
References Cited (Backward Citations)
US3827237A
Cited
FR2163297A5
Cited
US4345432A
Cited
GB2077962A
Cited
EP0048808A1
Cited
DE3339429A1
Cited
EP0277578A2
Cited
DE4029672C2
Cited
DE4029672A1
Cited
EP0499207A1
Cited
US5237818A
Cited
DE4112478A1
Cited
DE4128823A1
Cited
US5249560A
Cited
US5535586A
Cited
EP0599061A1
Cited
DE4342656A1
Cited
US5522219A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-09-01 | 2001-03-03 | 2001-09-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-09-01 | 2005-03-03 | 2005-09-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-09-01 | 2009-03-03 | 2009-09-02 | $7700.00 | Window Closed / Lapsed |