Emission control system
AssigneeFord Global Technologies, LLC
InventorsBrien Lloyd Fulton, Katie Jo Vantine, Simon Goodliff
Life of this patent
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Abstract
A reductant injection control strategy for controlling an amount of nitrogen oxide reducing agent injected upstream of a first and second serially placed nitrogen oxide catalyst, calculates the reductant injection For the first catalyst and second catalyst. The reductant injection for the first catalyst is based on engine operating conditions. The reductant injection for the second catalyst is based on the reductant injection for the first catalyst and a conversion efficiency of the first catalyst.
Claims21
A method for adding reductant to at least first and second catalysts serially disposed in an engine exhaust, the method comprising the steps of:
- generating a first reductant quantity based on engine operating conditions representative of a nitrogen oxide quantity produced by the engine;
- determining a conversion efficiency of the first catalyst based on operating conditions;
- generating a second reductant quantity based on said first reductant injection quantity and said conversion efficiency;
- adding reductant to the first catalyst according to said first reductant quantity;
- and
- adding reductant to the second catalyst according to said second reductant quantity.
A method for controlling first and second reductant injectors coupled to first and second catalyst, with the first and second catalysts coupled to an internal combustion engine, wherein the first catalyst is located upstream of the second catalyst, the method comprising the steps of:
- generating a first reductant injection quantity based on engine operating conditions representative of a nitrogen oxide quantity produced by the engine and a temperature of the first catalyst;
- determining a conversion efficiency of the first catalyst based on an engine speed, said temperature of the first catalyst, and an engine fuel injection quantity;
- generating a second reductant injection quantity based on said first reductant injection quantity and said conversion efficiency;
- controlling the first injector according to said first reductant injection quantity;
- and
- controlling the second injector according to said second reductant injection quantity.
An article of manufacture comprising:
- a computer storage medium having a computer program encoded therein for controlling the amount of reductant adding to first and second catalysts serially disposed in an engine exhaust, said computer storage medium comprising:
- code for generating a first reductant quantity based on engine operating conditions representative of a nitrogen oxide quantity produced by the engine;
- code determining a conversion efficiency of the first catalyst based on operating conditions;
- code for generating a second reductant quantity based on said first reductant injection quantity and said conversion efficiency;
- code for adding reductant to the first catalyst according to said first reductant quantity;
- and
- code for adding reductant to the second catalyst according to said second reductant quantity.
Dependencies are inferred from the claim text.