EXHAUST GAS PURIFICATION SYSTEM FOR INTERNAL COMBUSTION ENGINE AND EXHAUST GAS PURIFICATION METHOD FOR INTERNAL COMBUSTION ENGINE

摘要

PROBLEM TO BE SOLVED: To provide an exhaust gas purification system for internal combustion engine and an exhaust gas purification method for internal combustion engine that can improve purification performance for a component to be purified in an exhaust gas discharged from an internal combustion engine, and also can prevent a component to be purified which temporarily has high concentration from being discharged to the atmosphere.SOLUTION: An exhaust gas purification system for internal combustion engine is provided with a first switching mechanism 21 which performs switching between a first state in which an exhaust gas G downstream from an exhaust gas purification device 12 flows to an exhaust passage 11 not through an adsorption device 20 and a second state in which the gas G flows to the exhaust passage 11 through the adsorption device 20, and also provided with a second switching mechanism 22 which performs switching between a third state in which an exhaust gas G upstream from the exhaust gas purification device 12 flows to the exhaust gas purification device 12 not through the adsorption device 20 and a fourth state in which the exhaust gas G flows to the exhaust gas purification device 12 through the adsorption device 20.