Exhaust emission control apparatus for on-board internal combustion engine, and method for exhaust emission control apparatus

摘要

A controller calculates a period travel distance that is a travel distance of the vehicle from when the available travel distance is calculated to when the available travel distance is calculated next. The controller, when the remaining amount of urea aqueous solution inside a tank exceeds a predetermined amount, executes a first calculation process in which the available travel distance is calculated with reference to the remaining amount of the urea aqueous solution. The controller, after the remaining amount of the urea aqueous solution becomes smaller than or equal to a predetermined amount, executes a second calculation process in which the available travel distance is calculated by subtracting the period travel distance from the previously calculated available travel distance.