| 摘要 |
PROBLEM TO BE SOLVED: To provide an exhaust purification system which can optimize a NOx purification rate of a selective reduction catalyst regardless of a state of the vehicle.SOLUTION: An exhaust purification system includes: a separation filter 32 which simultaneously calculates from an output value Ynox of a NOx sensor an estimated value NOx_DW_hat of NOx concentration on a downstream side from a SCR catalyst and an estimated value NH3_DW_hat of NHconcentration on the downstream side from the SCR catalyst in each prescribed control period; and a feedback controller 35 which calculates a feedback input Gnh3_fb by an extremal value search controller so as to minimize an output value Ynox of the NOx sensor when a vehicle is in a cruising state, and calculates the feedback input Gnh3_fb by a sliding mode controller so that both or either of a downstream NOx estimated value NOx_DW_hat and downstream NHestimated value NH3_DW_hat calculated by the separation filter 32 become respective target values when in a transient state other than the cruising state. |
