Patent ID: 7963102
Filing Date: 2011-06-21
Classification: F01N,F02D

Abstract:
1. An exhaust purification system for an internal combustion engine, comprising: an exhaust passage, one end of which is connected to said internal combustion engine, through which exhaust gas from said internal combustion engine passes, and which bifurcates midway into a plurality of branch passages; an exhaust purification device provided in each of said plurality of branch passages for purifying said exhaust gas passing through each of said branch passages; an exhaust flow control valve provided in each of said plurality of branch passages for controlling a flow rate of said exhaust gas passing through each of said branch passages; a reducer adding device provided upstream of said exhaust purification device in each of said plurality of branch passages for adding a reducer to said exhaust gas passing through each of said branch passages; and a controller configured to control the exhaust flow control valve in each of said plurality of branch passages, such that, when said exhaust purification device provided in one of said plurality of branch passages is to be subjected to purification performance regeneration by supplying said reducer to said exhaust purification device, the controller controls said exhaust flow control valve in a branch passage provided with said exhaust purification device to be subjected to purification performance regeneration, from among said plurality of branch passages, to be substantially fully closed, and closes said exhaust flow control valve in at least one of the other branch passages such that an opening of said exhaust gas flow control valve in the at least one of the other branch passages is opened to a predetermined purification performance regeneration opening, wherein the controller is further configured to set a predetermined time difference between an operation to substantially fully close said exhaust flow control valve in said branch passage provided with said exhaust purification device to be subjected to purification performance regeneration, and an operation to set said opening of said exhaust flow control valve in at least one of said other branch passages to said predetermined purification performance regeneration opening, wherein, when an operational state of said internal combustion engine is in a predetermined low range region and said purification performance of said exhaust purification device provided in one of said plurality of branch passages is to be regenerated by supplying said reducer to said exhaust purification device, the controller is further configured to set said opening of said exhaust flow control valve in at least one of said other branch passages to said purification performance regeneration opening, and wherein, after the lapse of a predetermined first time period, the controller is further configured to substantially fully close said exhaust flow control valve in said branch passage provided with said exhaust purification device to be subjected to purification performance regeneration.