US5740669A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Exhaust gas purification device for an engine
Assignee: Toyota Motor Corp
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Filing: 1995-11-16
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Granted: 1998-04-21
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Expires: 2015-11-16
Abstract
Abstract In the present invention, a NO x absorbent is used for removing the NO x in the exhaust gas. The NO x absorbent absorbs NO x in the exhaust gas when the air-fuel ratio of the exhaust gas is lean, and releases the absorbed NO x and reduces it to nitrogen when the air-fuel ratio of the exhaust gas is rich or stoichiometric. To prevent the NO x absorbent from being saturated with the absorbed NO x , the NO x absorbent must be regenerated periodically by causing the NO x in the absorbent to be released and reduced. However, it is found that when the regenerating process by supplying a rich air-fuel ratio exhaust gas to the NO x absorbent is carried out at high NO x absorbent temperature, a part of NO x flows out from the NO x absorbent at the beginning of the regenerating process without being reduced. In the present invention, this outflow of NO x is suppressed by, for example, carrying out the regenerating process only when the temperature of the NO x absorbent is lowered to a predetermined temperature. This predetermined temperature is set low enough to ensure that the amount of the outflow of NO x is minimized.
Inventors
- 👤 Yukio Kinugasa
- 👤 Kouhei Igarashi
- 👤 Takaaki Itou
- 👤 Toshifumi Takaoka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 06:11
CPC Classifications
F; F01; F01N; F01N3/00; F01N3/08; F01N3/0807; F01N3/0828; F01N3/0842; F01N13/00; F01N13/009; F01N3/0871; F01N3/10; F01N3/24; F01N3/30; F01N9/00; F02; F02D; F02D41/00; F02D41/02; F02D41/021; F02D41/0235; F02D41/027; F02D41/0275; F01N2240/00; F01N2240/18; F01N2390/00; F01N2390/02; F01N2430/00; F01N2430/06; F02D2200/00; F02D2200/02; F02D2200/08; F02D2200/0802; Y; Y02; Y02C; Y02C20/00; Y02C20/10; Y02T; Y02T10/00; Y02T10/10; Y02T10/40
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
208 words
An exhaust gas purification device for an internal combustion engine comprising: a NO x absorbent disposed in an exhaust passage of an internal combustion engine, wherein the NO x absorbent absorbs NO x in exhaust gas from the engine 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 oxygen concentration in the exhaust gas becomes lower; temperature detecting means for detecting a temperature of the NO x absorbent; regenerating means for causing the air-fuel ratio of the exhaust gas flowing into the NO x absorbent to become one of a rich air-fuel ratio and a stoichiometric air-fuel ratio to cause the NO x accumulated in the NO x absorbent to be released from the NO x absorbent and to be reduced to nitrogen; and regeneration control means for activating the regenerating means to cause the air-fuel ratio of the exhaust gas flowing into the NO x absorbent to become one of a rich air-fuel ratio and a stoichiometric air-fuel ratio only when the temperature of the NO x absorbent is lower than a predetermined temperature and an amount of NO x accumulated in the NO x absorbent is at least a predetermined amount.
Claim 2
Dependent Claim
208 words
An exhaust gas purification device for an internal combustion engine comprising: a NO x absorbent disposed in an exhaust passage of an internal combustion engine, wherein the NO x absorbent absorbs NO x in exhaust gas from the engine 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 oxygen concentration in the exhaust gas becomes lower; temperature detecting means for detecting a temperature of the NO x absorbent; regenerating means for causing the air-fuel ratio of the exhaust gas flowing into the NO x absorbent to become one of a rich air-fuel ratio and a stoichiometric air-fuel ratio to cause the NO x accumulated in the NO x absorbent to be released from the NO x absorbent and to be reduced to nitrogen; and regeneration control means for activating the regenerating means to cause the air-fuel ratio of the exhaust gas flowing into the NO x absorbent to become one of a rich air-fuel ratio and a stoichiometric air-fuel ratio only when the temperature of the NO x absorbent is lower than a predetermined temperature and an amount of NO x accumulated in the NO x absorbent is at least a predetermined amount.
Claim 3
Dependent Claim
48 words
An exhaust gas purification device according to claim 1, wherein said regeneration control means prohibits the regenerating means from causing the air-fuel ratio of the exhaust gas to-become rich or stoichiometric when the temperature of the NO x absorbent is higher than or equal to said predetermined temperature.
Claim 4
Dependent Claim
59 words
An exhaust gas purification device according to claim 1, wherein said regeneration control means comprises a temperature control means for keeping the temperature of the NO x absorbent at lower than said predetermined temperature at least when the regenerating means causes the air-fuel ratio of the exhaust gas flowing into the NO x absorbent to become rich or stoichiometric.
Claim 5
Dependent Claim
196 words
An exhaust gas purification device for an internal combustion engine comprising: a NO x absorbent disposed in an exhaust passage of an internal combustion engine, wherein the NO x absorbent absorbs NO x in exhaust gas from the engine 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 oxygen concentration in the exhaust gas becomes lower; regenerating means for causing the air-fuel ratio of the exhaust gas flowing into the NO x absorbent to become one of a rich air-fuel ratio and a stoichiometric air-fuel ratio to cause the NO x accumulated in the NO x absorbent to be released from the NO x absorbent and to be reduced to nitrogen; activating means for activating the regenerating means when the amount of NO x accumulated in the NO x absorbent reaches a predetermined value; temperature detecting means for detecting a temperature of the NO x absorbent; and regeneration timing control means for controlling the activating means in such a manner that the timing of the activation of the regenerating means is delayed as the temperature of the NO x absorbent increases.
Claim 6
Dependent Claim
196 words
An exhaust gas purification device for an internal combustion engine comprising: a NO x absorbent disposed in an exhaust passage of an internal combustion engine, wherein the NO x absorbent absorbs NO x in exhaust gas from the engine 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 oxygen concentration in the exhaust gas becomes lower; regenerating means for causing the air-fuel ratio of the exhaust gas flowing into the NO x absorbent to become one of a rich air-fuel ratio and a stoichiometric air-fuel ratio to cause the NO x accumulated in the NO x absorbent to be released from the NO x absorbent and to be reduced to nitrogen; activating means for activating the regenerating means when the amount of NO x accumulated in the NO x absorbent reaches a predetermined value; temperature detecting means for detecting a temperature of the NO x absorbent; and regeneration timing control means for controlling the activating means in such a manner that the timing of the activation of the regenerating means is delayed as the temperature of the NO x absorbent increases.
Claim 7
Dependent Claim
79 words
An exhaust gas purification device according to claim 4, wherein said activating means comprises NO x amount detecting means for detecting the amount of the NO x accumulated in the NO x absorbent and activates the regenerating means when the amount of the NO x accumulated in the NO x absorbent becomes larger than a predetermined set value, and wherein said regeneration timing control means increases said set value as the temperature of the NO x absorbent becomes high.
References Cited (Backward Citations)
US3819334A
Cited
US5357749A
Cited
WO1993007363A1
Cited
US5437153A
Cited
JPH0610725A
Cited
US5402641A
Cited
JPH0693842A
Cited
JPH06108834A
Cited
JPH06129235A
Cited
US5461857A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-04-20 | 2001-10-20 | 2002-04-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-04-20 | 2005-10-20 | 2006-04-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-04-20 | 2009-10-20 | 2010-04-21 | $7700.00 | Window Closed / Lapsed |