内燃機関の排気ガス浄化システム及び内燃機関の排気ガス浄化方法

摘要

To provide an exhaust emission control system of an internal combustion engine and an exhaust emission control method of the internal combustion engine capable of optimizing an amount of a reducer to variation of a catalyst temperature during a period of controlling a rich air-fuel ratio, in an exhaust emission control system including a NOx catalyst device having a NOx adsorption function, in particular, in the NOx catalyst device in which a rich reduction temperature range and a NOx slip temperature range are close to each other.SOLUTION: An NOx emission amount from a NOx catalyst device 21 is calculated by directly or indirectly using an acquired catalyst temperature during a period of rich air-fuel ratio control in regeneration control, then an amount of reducer necessary for controlling the rich air-fuel ratio is calculated from the NOx emission amount, and the reducer is supplied to an exhaust gas on the basis of a reducer supply amount.SELECTED DRAWING: Figure 2