Emission control diagnostic system and method
AssigneeFord Global Technologies, LLC
InventorsMichiel J. Van Nieuwstadt, Emil G. Serban
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Abstract
A method of diagnosing an emission control system of an internal combustion engine, comprising during degraded performance of the emission control system, dynamically identifying a relationship between a plurality of operating conditions of the emission control system; and correlating the relationship to a plurality of potential sources of degraded performance of the emission control system to identify at least one degraded source among the plurality of potential sources.
Claims17
A method of diagnosing an emission control system of an internal combustion engine including a selective catalyst reduction catalyst and a reductant injection system configured to inject reductant to the emission control system, the method comprising:
- during degraded performance of the emission control system, dynamically identifying a relationship between a plurality of operating conditions of the emission control system;
- correlating the relationship to a plurality of potential sources of degraded performance of the emission control system to identify at least one degraded source among said plurality of potential sources, said plurality of sources including the reductant injection system, the selective catalytic reduction catalyst, and a reductant quality;
- and
- indicating which of said plurality of sources was identified as degraded.
A method of operating an internal combustion engine having an emission control system including a reductant injection system configured to inject reductant to the emission control system, the emission control system further including a selective catalyst reduction catalyst, the method comprising:
- determining degraded performance of the emission control system;
- sequentially diagnosing a plurality of potential sources of degraded performance where a different combination of detected operating conditions is determined for each of said plurality of potential sources, the sequential diagnoses including sequentially diagnosing the injection system, the selective catalytic reduction catalyst, and a reductant quality;
- and
- distinguishing at least one degraded source from said plurality of potential sources based on said combination of detected operating conditions corresponding to said distinguished source.
An apparatus, comprising:
- an internal combustion engine;
- an emission control device including a catalyst for controlling emissions from the engine;
- an injection system comprising an injector configured to selectively supply a reductant to the emission control device;
- a nitrogen oxide sensor disposed downstream an emission control device;
- an ammonia sensor disposed downstream the emission control device;
- a temperature sensor fluidically disposed between the injector and the emission control device;
- a controller comprising memory and a processor, the memory comprising instructions executable by the processor to:
- determine a degraded performance of the emission control system;
- dynamically identify a relationship based on feedback from the nitrogen oxide sensor and at least one of the ammonia sensor and the temperature sensor;
- and
- correlate the relationship to a plurality of potential sources of degraded performance to identify at least one degraded sources among said plurality of potential sources.
Dependencies are inferred from the claim text.