Emission control system
AssigneeFord Global Technologies, LLC
InventorsRobert Henry Hammerle, Karen Marie Adams, Paul Matthew Laing
Life of this patent
Estimating the term…
Abstract
A reductant injection control strategy for controlling an amount of nitrogen oxide reducing agent injected upstream of a selective reduction catalyst uses a NOx sensor located downstream of the catalyst. An open loop injection quantity is first determined based on operation conditions. Nitrogen oxide conversion efficiency of the catalyst is controlled by controlling the reductant injection based on after catalyst NOx sensor reading and engine out nitrogen oxide concentration.
Claims8
A method for controlling a reductant injection upstream of a catalyst coupled to an internal combustion engine, the method comprising the steps of:
- generating a reductant injection quantity based on a nitrogen oxide concentration entering the catalyst;
- determining a nitrogen oxide conversion efficiency of the catalyst;
- generating a desired NOx conversion efficiency value based on a catalyst temperature and said nitrogen oxide concentration entering the catalyst;
- and
- adjusting said injection quantity to obtain said desired NOx conversion efficiency value.
An article of manufacture comprising:
- a computer storage medium having a computer program encoded therein for controlling a reductant injection upstream of a catalyst coupled to an internal combustion engine, said computer storage medium comprising:
- code for generating a reductant injection quantity based on a nitrogen oxide concentration entering the catalyst;
- code for determining a nitrogen oxide conversion efficiency of the catalyst;
- code for generating a desired NOx conversion efficiency value based on a catalyst temperature and said nitrogen oxide concentration entering the catalyst;
- and
- code for adjusting said injection quantity to obtain said desired NOx conversion efficiency value.
Dependencies are inferred from the claim text.