Patent ID: 8037676

Claim:
A regeneration control method for an exhaust gas purification system, comprising: providing an exhaust gas purification apparatus in an exhaust passage of an internal combustion engine; providing a reducing agent supplying apparatus in an upstream side of the exhaust gas purification apparatus; providing a control unit that controls a supply of the reducing agent from the reducing agent supplying apparatus into an exhaust gas flowing into the exhaust gas purification apparatus during regeneration control to recover purification capability of the exhaust gas purification apparatus; providing a first branched exhaust passage and a second branched exhaust passage by branching the exhaust passage in the upstream side of the exhaust gas purification apparatus and merging the first and second branched exhaust passages at a confluence in the upstream side of the exhaust gas purification apparatus; arranging the reducing agent supplying apparatus in the first branched exhaust passage, and at the same time; and providing a flow path controller in each of the first and second branched exhaust gas passages upstream of the confluence that controls a flow of the exhaust gas in the first or second branched exhaust passages, wherein the flow path controller in the first branched passage is located between the reducing agent supplying apparatus and the confluence, wherein, when the reducing agent is supplied at the time of regeneration, the respective flow path controllers control the flow of the exhaust gas in the first branched exhaust passage or in the second branched exhaust passage, so that a concentration of the reducing agent supplied to the exhaust gas purification apparatus is temporarily changed in response to a temporal change of the condition of the exhaust gas purification system at the time of regeneration.