US5501074A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Exhaust gas purifying system
Assignee: Mazda Motor Corp
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Filing: 1994-03-22
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Granted: 1996-03-26
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Expires: 2014-03-22
Abstract
Abstract An exhaust gas purifying system for an automobile engine is equipped with a metal zeolite catalytic converter for deoxidizing and purifying nitrogen oxides in exhaust gas. The system controls and compulsorily changes the air-fuel ratio of the fuel mixture injected into the automobile engine based on a target air-fuel ratio only when the temperature of the exhaust gas, before entering the catalyst, is greater than a specific temperature.
Inventors
- 👤 Hajime Suetsugu
- 👤 Tadataka Nakazumi
- 👤 Akihide Takami
- 👤 Takashi Takemoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 06:34
CPC Classifications
F; F02; F02D; F02D41/00; F02D41/02; F02D41/14; F02D41/1438; F02D41/1444; F02D41/1446; F02D41/1401; F02D41/1408; F01; F01N; F01N2370/00; F01N2370/02; F01N2370/04
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
139 words
An exhaust gas purifying system having a catalytic converter, which is disposed in an exhaust line so as to deoxidize or reduce and purify nitrogen oxides in exhaust gases, for an automobile engine, said exhaust gas purifying system comprising: an air-fuel ratio sensor for detecting an air-fuel ratio of a fuel mixture based on an oxygen concentration in exhaust gas discharged from said automobile engine; a temperature sensor disposed upstream from said catalytic converter in said exhaust line for detecting temperature of exhaust gas; and control means for computing a target air-fuel ratio of a fuel mixture to be introduced into said automobile engine based on engine operating conditions, and compulsorily perturbing the air-fuel ratio of said fuel mixture based on said target air-fuel ratio only when said temperature sensor detects exhaust gas temperature greater than a specific temperature.
Claim 2
Dependent Claim
139 words
An exhaust gas purifying system having a catalytic converter, which is disposed in an exhaust line so as to deoxidize or reduce and purify nitrogen oxides in exhaust gases, for an automobile engine, said exhaust gas purifying system comprising: an air-fuel ratio sensor for detecting an air-fuel ratio of a fuel mixture based on an oxygen concentration in exhaust gas discharged from said automobile engine; a temperature sensor disposed upstream from said catalytic converter in said exhaust line for detecting temperature of exhaust gas; and control means for computing a target air-fuel ratio of a fuel mixture to be introduced into said automobile engine based on engine operating conditions, and compulsorily perturbing the air-fuel ratio of said fuel mixture based on said target air-fuel ratio only when said temperature sensor detects exhaust gas temperature greater than a specific temperature.
Claim 3
Dependent Claim
20 words
An exhaust gas purifying system as defined in claim 1, wherein said catalytic converter includes a precious metal zeolite catalyst.
Claim 4
Dependent Claim
28 words
An exhaust gas purifying system as defined in claim 2, wherein said precious metal zeolite catalyst is composed of zeolite with at least platinum and iridium contained thereon.
Claim 5
Dependent Claim
38 words
An exhaust gas purifying system as defined in claim 2, wherein said control means sets said specific temperature to that temperature at which said catalytic converter exhibits the highest exhaust gas purifying rate under said target air-fuel ratio.
Claim 6
Dependent Claim
36 words
An exhaust gas purifying system as defined in claim 2, wherein said control means further controls said specific temperature to a lower value when detecting a change in said target air-fuel ratio toward a lean side.
Claim 7
Dependent Claim
38 words
An exhaust gas purifying system as defined in claim 2, wherein said control means computes said target air-fuel ratio based on rotational speed of said automobile engine and a quantity of intake air introduced into said automobile engine.
Claim 8
Dependent Claim
25 words
An exhaust gas purifying system as defined in claim 1, wherein said temperature sensor is disposed upstream from said catalytic converter in said exhaust line.
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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) | 1999-03-26 | 1999-09-25 | 2000-03-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-03-26 | 2003-09-25 | 2004-03-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-03-26 | 2007-09-25 | 2008-03-26 | $7700.00 | Window Closed / Lapsed |