IPC분류정보
국가/구분 |
United States(US) Patent
등록
|
국제특허분류(IPC7판) |
|
출원번호 |
US-0269043
(2002-10-11)
|
우선권정보 |
JP-0315879 (2001-10-12) |
발명자
/ 주소 |
- Kokusyo, Hajime
- Kitahara, Yasuhisa
- Kaneko, Hiroaki
- Kamijo, Motohisa
|
출원인 / 주소 |
|
대리인 / 주소 |
|
인용정보 |
피인용 횟수 :
5 인용 특허 :
6 |
초록
▼
In order to improve performance of NOx reduction, an additional fuel injection immediately after a main fuel injection is performed. By such additional fuel injection, hydrogen (H 2 ) is supplied to a NOx trap catalyst. And in order to prevent engine output torque from varying by the additional fue
In order to improve performance of NOx reduction, an additional fuel injection immediately after a main fuel injection is performed. By such additional fuel injection, hydrogen (H 2 ) is supplied to a NOx trap catalyst. And in order to prevent engine output torque from varying by the additional fuel injection, the main fuel injection is controlled by whether the additional fuel injection is performed.
대표청구항
▼
1. An exhaust gas purification device for a diesel engine having an injector injecting fuel directly into a combustion chamber of the engine, comprising:a NOx trap catalyst trapping nitrogen oxides (NOx) contained in exhaust gas when an air-fuel ratio of the exhaust gas is leaner than stoichiometric
1. An exhaust gas purification device for a diesel engine having an injector injecting fuel directly into a combustion chamber of the engine, comprising:a NOx trap catalyst trapping nitrogen oxides (NOx) contained in exhaust gas when an air-fuel ratio of the exhaust gas is leaner than stoichiometric air-fuel ratio, and reducing NOx stored in the catalyst when the air-fuel ratio of the exhaust gas is richer than stoichiometric air-fuel ratio; anda controller programmed to:make a judgment as to whether the catalyst should be regenerated, an additional fuel injection being performed in accordance with the judgment;calculate instruction values regarding a main fuel injection, in accordance with engine operating conditions and the judgment;calculate instruction values regarding the additional fuel injection, when the judgment shows that the catalyst should be regenerated; andcontrol the injector according to the instruction values regarding the main and the additional fuel injection, in order to regenerate the catalyst. 2. An exhaust gas purification device as claimed in claim 1, wherein the instruction values regarding the additional fuel injection include a value indicating a timing of the additional fuel injection. 3. An exhaust gas purification device as claimed in claim 2, wherein the controller is further programmed to calculate the value indicating the additional fuel injection timing which is suitable for generating hydrogen (H 2 ). 4. An exhaust gas purification device as claimed in claim 3, wherein the H 2 is generated in a dehydrogenation reaction and a cracking reaction. 5. An exhaust gas purification device as claimed in claim 2, wherein the controller is further programmed to calculate the value indicating the additional fuel injection timing when temperature in the combustion chamber becomes higher than approximately 1600° C. 6. An exhaust gas purification device as claimed in claim 2, wherein the controller is further programmed to calculate the value indicating the additional fuel injection timing within a bound of 30 degree in crank-angle from a timing of the main fuel injection. 7. An exhaust gas purification device as claimed in claim 1, wherein the controller is further programmed to:calculate normal values regarding the main fuel injection based on the engine operating conditions; andcalculate the instruction values regarding the main fuel injection by making a correction to the normal values, when the judgment shows that the catalyst should be regenerated. 8. An exhaust gas purification device as claimed in claim 7, wherein the correction decreases engine torque to be generated by the main fuel injection. 9. An exhaust gas purification device as claimed in claim 8, wherein the normal values include a value indicating a timing of the main fuel injection, and the correction retards the main fuel injection timing. 10. An exhaust gas purification device as claimed in claim 8, wherein the normal values include a value indicating an amount of the main fuel injection, and the correction decreases the main fuel injection amount. 11. An exhaust gas purification device as claimed in claim 8, wherein the engine is operable with diffusion combustion or premixed combustion, and the normal values include a value indicating a timing of the main fuel injection and a value indicating an amount of the main fuel injection, and the correction which is made at timing of the diffusion combustion retards the main fuel injection timing, and the correction which is made at timing of the premixed combustion decreases the main fuel injection amount. 12. An exhaust gas purification device as claimed in claim 1, wherein the controller is further programmed to:calculate normal values regarding the main fuel injection based on the engine operating conditions;make a second judgment as to whether the catalyst is active;calculate the instruction values regarding the main fuel injection by making a correction to the normal values, when the judgment shows that the catalyst should be regenerated and the second judgment shows that the catalyst is inactive; andcalculate the instruction values regarding the main fuel injection according to the normal values without the correction, when the judgment shows that the catalyst should be regenerated and the second judgment shows that the catalyst is active. 13. An exhaust gas purification device as claimed in claim 12, wherein the instruction values regarding additional fuel injection include a value indicating a timing of the additional fuel injection, and the controller is further programmed to:calculate the instruction value regarding the additional fuel injection timing which is close to a timing of the main fuel injection, when the judgment shows that the catalyst should be regenerated and the second judgment shows that the catalyst is inactive; andcalculate the instruction value regarding the additional fuel injection timing which is far from the timing of the main fuel injection, when the judgment shows that the catalyst should be regenerated and the second judgment shows that the catalyst is active. 14. An exhaust gas purification device for a diesel engine having an injector injecting fuel directly into a combustion chamber of the engine, comprising:a NOx trap catalyst trapping nitrogen oxides (NOx) contained in exhaust gas when an air-fuel ratio of the exhaust gas is leaner than stoichiometric air-fuel ratio, and reducing NOx stored in the catalyst when the air-fuel ratio of the exhaust gas is richer than stoichiometric air-fuel ratio;means for making a judgment as to whether the catalyst should be regenerated performing an additional fuel injection according to the judgment;means for calculating instruction values regarding a main fuel injection, in accordance with engine operating conditions and the judgment;means for calculating instruction values regarding the additional fuel injection, when the judgment shows that the catalyst should be regenerated; andmeans for controlling the injector according to the instruction values regarding the main and the additional fuel injection, in order to regenerate the catalyst. 15. An exhaust gas purification method for a diesel engine having an injector injecting fuel directly into a combustion chamber of the engine, comprising:providing a NOx trap catalyst trapping nitrogen oxides (NOx) contained in exhaust gas when an air-fuel ratio of the exhaust gas is leaner than stoichiometric air-fuel ratio, and reducing NOx stored in the catalyst when the air-fuel ratio of the exhaust gas is richer than stoichiometric air-fuel ratio; andmaking a judgment as to whether the catalyst should be regenerated, and performing an additional fuel injection according to the judgment;calculating instruction values regarding a main fuel injection, in accordance with engine operating conditions and the judgment;calculating instruction values regarding the additional fuel injection, when the judgment shows that the catalyst should be regenerated; andcontrolling the injector according to the instruction values regarding the main and the additional fuel injection, in order to regenerate the catalyst.
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