EGR control system for internal combustion engine

摘要

An object of the present invention is to suppress the dispersion of EGR gas amount between cylinders when the stuck open state arises in an EGR valve in an EGR apparatus for an internal combustion engine in which an EGR passage is branched on an intake system side into a plurality of EGR branch pipes, and the respective EGR branch pipes are connected respectively to intake branch pipes provided for the respective cylinders. In the present invention, if the EGR valve is stuck open, the exhaust pressure is reduced in an exhaust system of the internal combustion engine, while suppressing an amount of decrease in a driving force of a vehicle which carries the internal combustion engine within an allowable range.

主权项

1. An EGR control system for an internal combustion engine, wherein:
the internal combustion engine comprises: a plurality of cylinders; a plurality of intake branch pipes which are formed by branching an intake passage and which are connected to the plurality of cylinders respectively; and an EGR apparatus which has an EGR passage for making communication between an exhaust system and an intake system of the internal combustion engine and which has an EGR valve for controlling an amount of EGR gas allowed to flow through the EGR passage, wherein: the EGR passage is branched into a plurality of EGR branch pipes on a side of the intake system, the respective EGR branch pipes are connected to the plurality of intake branch pipes respectively; and the EGR valve is arranged on an upstream side along a flow of the EGR gas as compared with a branched portion of the EGR passage, the EGR control system for the internal combustion engine further comprises: stuck open state judging unit which judges whether or not the EGR valve sticks in a valve open state; and exhaust pressure reducing unit which reduces an exhaust pressure in the exhaust system of the internal combustion engine, while suppressing an amount of decrease in a driving force of a vehicle which carries the internal combustion engine within an allowable range, if it is judged by the stuck open state judging unit that the EGR valve sticks in the valve open state.