Patent ID: 7856815

Claim:
An exhaust purification system for an internal combustion engine, comprising: an exhaust passageway through which exhausts discharged from a plurality of cylinder groups of the internal combustion engine pass, and which includes: cylinder group-directly coupled exhaust passageways which are connected respectively to the plurality of cylinder groups, and through which the exhausts discharged from the cylinder groups pass, and a number of which is equal to a number of the cylinder groups, cylinder group-respective branch passageways which are formed by division of each cylinder group-directly coupled exhaust passageway, numbers of the cylinder group-respective branch passageways of the individual cylinder group-directly coupled exhaust passageways being equal, mixture exhaust passageways each of which is formed by joining one of the cylinder group-respective branch passageways dividing from each one of the cylinder group-directly coupled exhaust passageways, with respect to all the cylinder group-directly coupled exhaust passageways, a number of the mixture exhaust passageways being equal to a number of cylinder group-respective branch passageways formed for a cylinder group, a junction mixture exhaust passageway formed by junction of all the mixture exhaust passageways, and an exhaust amount control portion which is provided for at least one of the mixture exhaust passageways and which controls an amount of exhaust that passes through the at least one of the mixture exhaust passageways; and one or more exhaust purification devices provided in the exhaust passageway and into which an exhaust that passes through the junction mixture exhaust passageway is introduced; wherein the exhaust amount control portion reduces the amount of exhaust that passes through at least one of the mixture exhaust passageways over a predetermined period after beginning of a cold start of the internal combustion engine.