Measuring and testing – Internal combustion engine or related engine system or... – Exhaust system
Reexamination Certificate
2008-01-10
2009-12-08
McCall, Eric S (Department: 2855)
Measuring and testing
Internal combustion engine or related engine system or...
Exhaust system
Reexamination Certificate
active
07628063
ABSTRACT:
An OBD system that diagnoses on board the condition of NOx adsorber catalysts in diesel engines and that relies on existing mass-produced exhaust gas oxygen sensor, also known as lambda sensor, technology, and the following established phenomena. In a reducing environment, typical exhaust gas oxygen (lambda) sensors have different sensitivities to various reductants, with sensitivity decreasing in this order: H2>CO>short-chain hydrocarbons>long-chain hydrocarbons. In the process of regeneration of the NOx adsorber catalyst, the original reductant may evolve into a different reductant species, e.g., via reactions such as a water-gas shift (WGS), a reforming, a partial oxidation, etc. This leads to a difference in exhaust gas oxygen sensor readings between the inlet to the catalyst and outlet from the catalyst. It has been observed in diesel engine testing that the ability of the NOx adsorber catalyst to perform such a reductant evolution is correlative to the catalyst's NOx reduction capability.
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Currier Neal W.
Epling William Shelbourne
Lafyatis David Scott
Millington Paul James
Popuri Sriram S.
Cummins Inc.
Krieg DeVault LLP
McCall Eric S
Schelkopf, Esq. J. Bruce
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