| 摘要 |
PROBLEM TO BE SOLVED: To provide an internal combustion engine emission control system capable of highly accurately estimating the oxidation property of a catalyst so as to be able to inject an appropriate quantity of fuel.SOLUTION: An internal combustion engine exhaust emission control system comprises: an oxidation capacity estimation means estimating the HC oxidation capacity of an LNT; exhaust fuel injection control means controlling an exhaust fuel injection amount on the basis of the HC oxidation capacity; catalyst temperature estimation means estimating the temperature of the catalyst using a catalyst heat thermal model that has at least two terms of an exhaust heat correlation term in proportion to a temperature of exhaust gas flowing into the LNT and a heating term in proportion to a quantity of fuel Gfuel_c flowing into the LNT; and identification means sequentially identifying a value of a coefficient b and a value of a coefficient c included in the heating term so as to narrow the difference between a detection value of a catalyst temperature sensor and an estimated value of the catalyst temperature estimation means. The HC oxidation capacity of the LNT is estimated using the coefficient c. The identification means updates the value of the coefficient b if the quantity of inflow fuel is zero, and updates the value of the coefficient c while fixing the value of the coefficient b if the quantity of inflow fuel is not zero. |
