To enrich an air-fuel ratio at the time of reducing NOx occluded in a NOx catalyst in a supercharger of an engine 1 having an exhaust gas turbo-charger 61 and a NOx catalyst (lean NOx catalyst section 43c) for reducing by occluding NOx therein; and to improve acceleration response at the time of reduction of the NOx or acceleration demand just after completing the reduction.
The NOx occluded in the NOx catalyst is reduced by enriching the air-fuel ratio of the exhaust gas so that an opening degree of a suction bypass valve 65 arranged on a suction bypass passage 64 for bypassing a compressor 61a of an exhaust gas turbocharger 61 is set up to be larger than an opening degree of a suction bypass valve arranged in response to operating conditions of the engine 1 and an opening degree of a regulator valve 68 arranged on a first exhaust gas bypass passage 67 for bypassing a turbine 61b of the exhaust gas turbo-charger 61 is set up to be equal or below in comparison with the opening degree of the regulator valve arranged in response to operating conditions of the engine 1.
COPYRIGHT: (C)2009,JPO&INPIT
| JP2007218143A | ||||
| JP2008002319A |
Hiroshi Maeda
Hiroshi Takeuchi
Takahisa Shimada
Yuji Takeuchi
Katsumi Imae
Atsushi Fujita
Kazunari Ninomiya
Tomoo Harada
Iseki Katsumori
Seki Kei
Yasuya Sugiura