| 摘要 |
<P>PROBLEM TO BE SOLVED: To effectively suppress the occurrence of PM poisoning in an EGR system, in an internal combustion engine having an EGR system. <P>SOLUTION: An exhaust emission control system includes a turbocharger 30 of twin entry type, first and second exhaust manifolds 32, 34 for flowing exhaust gas of first and second cylinder groups into respective inlet ports of a turbine 301, an exhaust passage 36 connected to an outlet port of the turbine 301, a start catalyst 38 arranged midway of the exhaust passage 36, an EGR passage 42 connecting the first exhaust manifold 32 with the intake manifold 12, an EGR catalyst 46 arranged midway of the EGR passage 42, and a PM sensor 53 for acquiring a PM amount included in exhaust gas on a downstream side of the EGR catalyst 46. An exhaust air-fuel ratio of the first cylinder group is corrected to an air-fuel ratio for minimizing the PM amount, and an exhaust air-fuel ratio of the second cylinder group is corrected so that an air-fuel ratio of exhaust gas flowing into the start catalyst 38 may be a stoichiometric air-fuel ratio. <P>COPYRIGHT: (C)2012,JPO&INPIT |
