Exhaust Purification System for Internal Combustion Engine

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;
• and
• 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,
• wherein, 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,
• 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, is substantially fully closed, and an opening of said exhaust flow control valve in at least one of the other branch passages is set at a predetermined purification performance regeneration opening.