CONTROL SYSTEM FOR INTERNAL COMBUSTION ENGINE

摘要

The present invention pertains to a control system for an internal combustion engine equipped with an exhaust gas purification apparatus including an NOx catalyst having an ability of reducing NOx and a particulate filter, and its object is to prevent deterioration in the acceleration performance while preventing an increase in exhaust emissions when the temperature of the NOx catalyst is low. The control system for an internal combustion engine according to the present invention includes an exhaust gas purification apparatus provided in an exhaust passage of the internal combustion engine and including an NOx catalyst having an ability of reducing NOx and a particulate filter, intake air quantity restriction means for restricting the intake air quantity in relation to the temperature of the NOx catalyst, fuel restriction means for restricting the fuel injection quantity in relation to the intake air quantity of the internal combustion engine, and trapped PM amount obtaining means for obtaining the amount of PM trapped in the particulate filter. When the amount of PM trapped in the particulate filter is not larger than a predetermined amount and the internal combustion engine is in an accelerating operation state, the control system corrects a restriction value of the fuel injection quantity in relation to the intake air quantity of the internal combustion engine and the temperature of the NOx catalyst.

主权项

1. A control system for an internal combustion engine comprising:
an exhaust gas purification apparatus arranged in an exhaust passage of the internal combustion engine and including an NOx catalyst having an ability of reducing NOx and a particulate filter; temperature obtaining unit for obtaining the temperature of said NOx catalyst; intake air quantity restriction unit that restricts the intake air quantity of the internal combustion engine in such a way as to make it smaller when the temperature obtained by said temperature obtaining unit is low than when the temperature obtained by said temperature obtaining unit is high; fuel restriction unit for restricting a fuel injection quantity in relation to the intake air quantity of the internal combustion engine; trapped PM amount obtaining unit for obtaining a trapped PM amount, which is defined to be the amount of particulate matter trapped in said particulate filter; and correction unit that corrects a restriction value of the fuel injection quantity, when the trapped PM amount obtained by said trapped PM amount obtaining unit is not larger than a predetermined amount and the internal combustion engine is in an accelerating operation state, in such a way that the restriction by said fuel restriction unit is more relaxed when the temperature obtained by said temperature obtaining unit is low and the intake air quantity restricted by said intake air quantity restriction unit is large than when the temperature obtained by said temperature obtaining unit is high and/or the intake air quantity restricted by said intake air quantity restriction unit is small.