US5388403A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Exhaust gas purification device for an engine
Assignee: Toyota Motor Corp
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Filing: 1994-02-28
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Granted: 1995-02-14
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Expires: 2014-02-28
Abstract
Abstract An engine comprising an exhaust passage having therein a NO x absorbent which absorbs the NO x when the air-fuel ratio of the exhaust gas flowing into the NO x absorbent is lean and releases the absorbed NO x when the concentration of oxygen in the exhaust gas is lowered. When the air-fuel ratio of air-fuel mixture fed into the engine cylinder is made a rich air-fuel ratio or the stoichiometric air-fuel ratio, a secondary air is fed into the exhaust passage upstream of the NO x absorbent to make the air-fuel ratio of exhaust gas lean.
Inventors
- 👤 Tetsuo Nagami
- 👤 Hiroshi Hirayama
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 20:10
CPC Classifications
F; F01; F01N; F01N3/00; F01N3/08; F01N3/10; F01N3/18; F01N3/22; F01N3/222; F01N13/00; F01N13/009; F01N3/0807; F01N3/0828; F01N3/0842; F01N3/0871; F02; F02D; F02D35/00; F02D35/0015; F02D35/0023; F02D35/0038; F01N2250/00; F01N2250/12; F01N3/20; F01N3/24; F01N3/30; F01N3/32; Y; Y02; Y02T; Y02T10/00; Y02T10/10; Y02T10/12
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
135 words
An exhaust gas purification device of an engine having a combustion chamber and an exhaust passage, said device comprising: a NO x absorbent arranged in the exhaust passage and absorbing NO x when an air-fuel ratio of exhaust gas flowing into said NO x absorbent is lean, said NO x absorbent releasing absorbed NO x when a concentration of oxygen in the exhaust gas flowing into said NO x absorbent is lowered; air-fuel ratio control means for controlling an air-fuel ratio of an air-fuel mixture formed in the combustion chamber; and secondary air supply means for feeding secondary air into the exhaust passage upstream of said NO x absorbent to make said air-fuel ratio of exhaust gas lean when said air-fuel ratio of said air-fuel mixture is made rich by said air-fuel ratio control means.
Claim 2
Dependent Claim
135 words
An exhaust gas purification device of an engine having a combustion chamber and an exhaust passage, said device comprising: a NO x absorbent arranged in the exhaust passage and absorbing NO x when an air-fuel ratio of exhaust gas flowing into said NO x absorbent is lean, said NO x absorbent releasing absorbed NO x when a concentration of oxygen in the exhaust gas flowing into said NO x absorbent is lowered; air-fuel ratio control means for controlling an air-fuel ratio of an air-fuel mixture formed in the combustion chamber; and secondary air supply means for feeding secondary air into the exhaust passage upstream of said NO x absorbent to make said air-fuel ratio of exhaust gas lean when said air-fuel ratio of said air-fuel mixture is made rich by said air-fuel ratio control means.
Claim 3
Dependent Claim
46 words
An exhaust gas purification device according to claim 1, wherein a three way catalyst is arranged in the exhaust passage upstream of said NO x absorbent, and said secondary air supply means feeds the secondary air into the exhaust passage upstream of said three way catalyst.
Claim 4
Dependent Claim
52 words
An exhaust gas purification device according to claim 1, wherein said secondary air supply means feeds the secondary air into the exhaust passage upstream of said NO x absorbent to make said air-fuel ratio of exhaust gas lean when said air-fuel ratio of said air-fuel mixture is made the stoichiometric air-fuel ratio.
Claim 5
Dependent Claim
34 words
An exhaust gas purification device according to claim 1, wherein said secondary air supply means stops the feeding operation of the secondary air when said air-fuel ratio of said air-fuel mixture is made lean.
Claim 6
Dependent Claim
40 words
An exhaust gas purification device according to claim 1, wherein said secondary air supply means starts the feeding operation of the secondary air when a predetermined time has elapsed after said air-fuel ratio of said air-fuel mixture is made rich.
Claim 7
Dependent Claim
49 words
An exhaust gas purification device according to claim 5, wherein estimating means for estimating the amount of NO x absorbed in said NO x absorbent is provided, and said predetermined time is made longer as an estimated amount of NO x absorbed in said NO x absorbent becomes larger.
Claim 8
Dependent Claim
29 words
An exhaust gas purification device according to claim 6, wherein said estimated amount of NO x absorbed in said NO x absorbent is calculated from a cumulative engine speed.
Claim 9
Dependent Claim
32 words
An exhaust gas purification device according to claim 1, wherein said secondary air supply means feeds the secondary air into the exhaust passage for a predetermined time after the engine is started.
Claim 10
Dependent Claim
137 words
An exhaust gas purification device according to claim 1, wherein estimating means for estimating the amount of NO x absorbed in said NO x absorbent is provided, and said air-fuel ratio control means switches over said air-fuel ratio of air-fuel mixture from a lean air-fuel ratio to a rich air-fuel ratio to release NO x from said NO x absorbent when an estimated amount of NO x absorbed in said NO x absorbent exceeds a predetermined amount, prohibiting means being provided for prohibiting the supply of secondary air by said secondary air supply means when said estimated amount of NO x absorbed in said NO x absorbent exceeds said predetermined amount and when said air-fuel ratio control means switches over said air-fuel ratio of said air-fuel mixture from the lean air-fuel ratio to the rich air-fuel ratio.
Claim 11
Dependent Claim
44 words
An exhaust gas purification device according to claim 1, wherein said NO x absorbent contains at least one substance selected from alkali metals comprising potassium, sodium, lithium, cesium; alkali earth metals comprising barium, calcium; and rare earth metals comprising lanthanum, yttrium and contains platinum.
References Cited (Backward Citations)
JPS6158912A
Cited
JPS6297630A
Cited
JPS62107826A
Cited
JPS62117620A
Cited
JPS6456816A
Cited
US4972737A
Cited
JPH01203609A
Cited
JPH03135417A
Cited
US5331809A
Cited
US5119631A
Cited
EP0503882A1
Cited
US5163412A
Cited
US5271223A
Cited
US5333446A
Cited
US5325663A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-02-13 | 1998-08-15 | 1999-02-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-02-13 | 2002-08-15 | 2003-02-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-02-13 | 2006-08-15 | 2007-02-14 | $7700.00 | Window Closed / Lapsed |