Patent ID: 7861518

Claim:
A method for controlling exhaust emissions from a combustion engine, the method comprising: determining a cost to operate a combustion engine including receiving a fuel price and a cost to operate an after-treatment device including receiving a reductant price; comparing the cost to operate the combustion engine with the cost to operate the after-treatment device; and at least one of adjusting one or more engine operating parameters and adjusting one or more after-treatment parameters, at least partially based on the comparison of the cost to operate the engine with the cost to operate the after-treatment device, wherein the one or more engine operating parameters determine a first mixture of exhaust emissions after combustion of fuel by the combustion engine, said one or more engine operating parameters comprising at least one of a fuel injector timing, an air-to-fuel ratio, an injection pressure, and a cooled exhaust gas recirculation airflow, and wherein the one or more after-treatment parameters determine a second mixture of exhaust emissions converted from the first exhaust emissions by the exhaust after-treatment device including a selective catalytic reduction device adapted to inject a reductant into the first exhaust emissions, said one or more after-treatment parameters comprising a reductant injection volume.