Patent ID: 8234855

Claim:
An exhaust gas purification device for an internal combustion engine having a four stroke fuel cycle, wherein the engine includes a plurality of combustion exhaust systems, with each combustion exhaust system provided with a cylinder group including a plurality of cylinders, each of which accommodates a piston, a cylinder head defining combustion chambers in the cylinders and including exhaust ports respectively corresponding to the cylinders, an exhaust valve associated with each exhaust port for opening and closing the exhaust port, an exhaust manifold connected to the cylinder head for merging exhaust gas discharged from the plurality of exhaust ports, and an exhaust passage connected to the exhaust manifold for discharging the merged exhaust gas, the discharge of the exhaust gas from the cylinders being started at an irregular interval and for each fuel cycle, an exhaust period in which one or more exhaust valves are opened to discharge exhaust gas from one or more cylinders and a blank period in which the exhaust valves are closed so that exhaust gas is not discharged from the cylinders existing in each of the plurality of cylinder groups, the purification device comprising: a purifier provided for each of the combustion exhaust systems to purge impurities from the exhaust gas in the corresponding exhaust passage; an additive supply device provided for each of the combustion exhaust systems and arranged in the exhaust port or a branch pipe of the exhaust manifold to supply additive to the corresponding purifier; and a control unit for controlling the additive supply devices so that each additive supply device intermittently performs continuous supply of additive and performs the continuous supply of additive during at least a portion of the exhaust period and throughout the entire blank period in the corresponding combustion exhaust system.