METHOD FOR CONTROLLING REDUCTANT AGENT STORAGE LEVEL IN EXHAUST GAS POST-TREATMENT DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a method for controlling a reductant agent buffering level in an exhaust gas post-treatment device that can be connected to a downstream side of an internal combustion engine.SOLUTION: This invention comprises: a step 310 of executing injection of the first reductant agent of the first amount at an upstream side of an exhaust gas post-treatment device; a step 320 of executing injection of the second reductant agent of the second amount at the upstream side of the exhaust gas post-treatment device; a step of making the second amount different from the first amount; a step 330 of evaluating NOx conversion resulted from the injection of the first and second reductant agent injections at the downstream side of the exhaust gas post-treatment device to attain the first and second results; and a step 340 of controlling the subsequent reductant agent injection in response to the first and second results got through the evaluations of the first and second NOx conversions.