IPC분류정보
국가/구분 |
United States(US) Patent
등록
|
국제특허분류(IPC7판) |
|
출원번호 |
US-0992756
(2006-10-16)
|
등록번호 |
US-8087236
(2012-01-03)
|
우선권정보 |
JP-2005-301682 (2005-10-17) |
국제출원번호 |
PCT/IB2006/002877
(2006-10-16)
|
§371/§102 date |
20080328
(20080328)
|
국제공개번호 |
WO2007/045988
(2007-04-26)
|
발명자
/ 주소 |
- Ueda, Takanori
- Oda, Tomihisa
- Niimi, Kuniaki
- Tsujimoto, Kenichi
|
출원인 / 주소 |
- Toyota Jidosha Kabushiki Kaisha
|
대리인 / 주소 |
|
인용정보 |
피인용 횟수 :
0 인용 특허 :
2 |
초록
▼
An exhaust gas purifying system for an internal combustion engine includes a first exhaust passage (22a) and a second exhaust passage (22b) into which an exhaust passage (21) of the internal combustion engine is bifurcated. NOx storage reduction catalysts (23a, 23b) and particulate filters (24a, 24b
An exhaust gas purifying system for an internal combustion engine includes a first exhaust passage (22a) and a second exhaust passage (22b) into which an exhaust passage (21) of the internal combustion engine is bifurcated. NOx storage reduction catalysts (23a, 23b) and particulate filters (24a, 24b) are provided in each of the exhaust passages (22a, 22b). Fuel is supplied from a fuel valve (32) when NOx is to be released from the NOx storage reduction catalysts (23a, 23b). At a timing when the supplied fuel attaches to the NOx storage reduction catalysts (23a, 23b), one of exhaust control valves, for example, a first exhaust control valve (26a) is temporarily closed so as to keep the air-fuel ratio of exhaust gas rich. When NOx is released from the NOx storage reduction catalysts (23a, 23b) next time, a second exhaust control valve (26b) is temporarily closed after the fuel is supplied.
대표청구항
▼
1. An exhaust gas purifying apparatus for an internal combustion engine including a first exhaust passage and a second exhaust passage into which a common exhaust passage provided upstream of the first and second passages is bifurcated, wherein a NOx absorbent is provided in each of the first exhaus
1. An exhaust gas purifying apparatus for an internal combustion engine including a first exhaust passage and a second exhaust passage into which a common exhaust passage provided upstream of the first and second passages is bifurcated, wherein a NOx absorbent is provided in each of the first exhaust passage and the second exhaust passage, the NOx absorbent storing NOx contained in exhaust gas when an air-fuel ratio of incoming exhaust gas becomes lean and releasing the NOx when the air-fuel ratio of incoming exhaust gas becomes rich, wherein: a fuel valve is provided in the common exhaust passage;when it is necessary to release NOx from the NOx absorbent provided in the first exhaust passage and from the NOx absorbent provided in the second exhaust passage, fuel is supplied from the fuel valve so as to make the air-fuel ratio of exhaust gas in both of the first exhaust passage and the second exhaust passage rich; andone of the first exhaust passage and the second exhaust passage is closed during a period during which the air-fuel ratio of exhaust gas in the one of the first exhaust passage and the second exhaust passage remains rich, after the fuel is supplied from the fuel valve. 2. The exhaust gas purifying apparatus for an internal combustion engine according to claim 1, wherein the one of the first exhaust passage and the second exhaust passage, which is closed during the period during which the air-fuel ratio of exhaust gas in the one of the first exhaust passage and the second exhaust passage remains rich, after the supply of fuel from the fuel valve, alternates between the first exhaust passage and the second exhaust passage each time the air-fuel ratio of the exhaust gas is made rich to release NOx from the NOx absorbent. 3. The exhaust gas purifying apparatus for an internal combustion engine according to claim 1, wherein a NOx storage-reduction catalyst on which the NOx absorbent is supported is provided in each of the first exhaust passage and the second exhaust passage. 4. The exhaust gas purifying apparatus for an internal combustion engine according to claim 1, wherein a particulate filter on which the NOx absorbent is supported is provided in each of the first exhaust passage and the second exhaust passage. 5. The exhaust gas purifying apparatus for an internal combustion engine according to claim 1, wherein at least one exhaust control valve is provided so as to close the first exhaust passage and the second exhaust passage. 6. The exhaust gas purifying apparatus for an internal combustion engine according to claim 1, wherein after the fuel is supplied from the fuel valve, the one of the first exhaust passage and the second exhaust passage is closed a first time period after the supply of fuel from the fuel valve and is opened a second time period after the closure of the one of the first exhaust passage and the second exhaust passage. 7. The exhaust gas purifying apparatus for an internal combustion engine according to claim 6, wherein the first time period is a time period that enables the fuel supplied from the fuel valve to remain in the one of the first exhaust passage and the second exhaust passage. 8. The exhaust gas purifying apparatus for an internal combustion engine according to claim 7, wherein the first time period is reduced as an intake amount increases. 9. The exhaust gas purifying apparatus for an internal combustion engine according to claim 7, wherein the first time period is reduced as a temperature of the NOx absorbent increases. 10. The exhaust gas purifying apparatus for an internal combustion engine according to claim 6, wherein the second time period is a time period during which the air-fuel ratio of exhaust gas in the one of the first exhaust passage and the second exhaust passage is kept rich. 11. The exhaust gas purifying apparatus for an internal combustion engine according to claim 10, wherein the second time period is reduced as an intake amount increases. 12. The exhaust gas purifying apparatus for an internal combustion engine according to claim 10, wherein the second time period is reduced as a temperature of the NOx absorbent increases. 13. The exhaust gas purifying apparatus for an internal combustion engine according to claim 1, wherein a particulate filter is provided in each of the first exhaust passage and the second exhaust passage; fuel is supplied from the fuel valve when the particulate filters need to be heated and one of the first exhaust passage and the second exhaust passage is closed during the period during which the air-fuel ratio of exhaust gas in the one of the first exhaust passage and the second exhaust passage remains rich, after the fuel is supplied from the fuel valve. 14. The exhaust gas purifying apparatus for an internal combustion engine according to claim 1, wherein fuel is supplied from the fuel valve when it is necessary to release SOx from the NOx absorbent so as to make the air-fuel ratio of exhaust gas in each of the first exhaust passage and the second exhaust passage rich; and one of the first exhaust passage and the second exhaust passage is closed during the period during which the air-fuel ratio of exhaust gas in the one of the first exhaust passage and the second exhaust passage remains rich, after the fuel is supplied from the fuel valve. 15. A method for controlling an exhaust gas purifying apparatus for an internal combustion engine including a first exhaust passage and a second exhaust passage into which a common exhaust passage provided upstream of the first exhaust passage and the second exhaust passage is bifurcated, wherein a NOx absorbent is provided in each of the first exhaust passage and the second exhaust passage, the NOx absorbent storing NOx contained in exhaust gas when an air-fuel ratio of incoming exhaust gas is lean and releasing the NOx when the air-fuel ratio of incoming exhaust gas is rich, a fuel valve being provided in the common exhaust passage, comprising: supplying fuel from the fuel valve so as to make the air-fuel ratio of exhaust gas in both of the first exhaust passage and the second exhaust passage rich, when it is necessary to release NOx from the NOx absorbent provided in the first exhaust passage and the NOx absorbent provided in the second exhaust passage; andclosing one of the first exhaust passage and the second exhaust passage during a period during which the air-fuel ratio of exhaust gas in the one of the first exhaust passage and the second exhaust passage remains rich, after the fuel is supplied from the fuel valve. 16. The control method for the exhaust gas purifying apparatus for an internal combustion engine according to claim 15, wherein the one of the first exhaust passage and the second exhaust passage, which is closed during the period during which the air-fuel ratio of exhaust gas in the one of the first exhaust passage and the second exhaust passage remains rich, after the supply of fuel from the fuel valve, alternates between the first exhaust passage and the second exhaust passage each time the air-fuel ratio of exhaust gas is made rich to release NOx from the NOx absorbent. 17. The control method for the exhaust gas purifying apparatus for an internal combustion engine according to claim 15, wherein after the fuel is supplied from the fuel valve, the one of the first exhaust passage and the second exhaust passage is closed a first time period after the supply of fuel from the fuel valve and then is opened a second time period after the closure of the one of the first exhaust passage and the second exhaust passage. 18. The control method for the exhaust gas purifying apparatus for an internal combustion engine according to claim 17, wherein the first time period is a time period that enables the fuel supplied from the fuel valve to remain in the one of the first exhaust passage and the second exhaust passage. 19. The control method for the exhaust gas purifying apparatus for an internal combustion engine according to claim 18, wherein the first time period is reduced as an intake amount increases. 20. The control method for the exhaust gas purifying apparatus for an internal combustion engine according to claim 18, wherein the first time period is reduced as a temperature of the NOx absorbent increases. 21. The control method for the exhaust gas purifying apparatus for an internal combustion engine according to claim 17, wherein the second time period is a time period during which the air-fuel ratio of exhaust gas in the one of the first exhaust passage and the second exhaust passage is kept rich. 22. The control method for the exhaust gas purifying apparatus for an internal combustion engine according to claim 21, wherein the second time period is reduced as an intake amount increases. 23. The control method for the exhaust gas purifying apparatus for an internal combustion engine according to claim 21, wherein the second time period is reduced as a temperature of the NOx absorbent increases. 24. The control method for the exhaust gas purifying apparatus for an internal combustion engine according to claim 15, wherein a particulate filter is provided in each of the first exhaust passage and the second exhaust passage; fuel is supplied from the fuel valve when the particulate filters need to be heated; andone of the first exhaust passage and the second exhaust passage is closed during the period during which the air-fuel ratio of exhaust gas in the one of the first exhaust passage and the second exhaust passage-remains rich, after the fuel is supplied from the fuel valve. 25. The control method for the exhaust gas purifying apparatus for an internal combustion engine according to claim 15, wherein fuel is supplied from the fuel valve when it is necessary to release SOx from the NOx absorbent, so as to make the air-fuel ratio of exhaust gas in each of the first exhaust passage and the second exhaust passage rich; and one of the first exhaust passage and the second exhaust passage is closed during a period during which the air-fuel ratio of exhaust gas in the one of the first exhaust passage and the second exhaust passage remains rich, after the fuel is supplied from the fuel valve.
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