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Exhaust emission control and diagnostics

Patent ·
OSTI ID:1175983
A diesel engine emission control system uses an upstream oxidation catalyst and a downstream SCR catalyst to reduce NOx in a lean exhaust gas environment. The engine and upstream oxidation catalyst are configured to provide approximately a 1:1 ratio of NO to NO2 entering the downstream catalyst. In this way, the downstream catalyst is insensitive to sulfur contamination, and also has improved overall catalyst NOx conversion efficiency. Degradation of the system is determined when the ratio provided is no longer near the desired 1:1 ratio. This condition is detected using measurements of engine operating conditions such as from a NOx sensor located downstream of the catalysts. Finally, control action to adjust an injected amount of reductant in the exhaust gas based on the actual NO to NO2 ratio upstream of the SCR catalyst and downstream of the oxidation catalyst.
Research Organization:
Ford Global Technologies, LLC, Dearborn, MI (United States)
Sponsoring Organization:
USDOE
DOE Contract Number:
FC26-01NT41103
Assignee:
Ford Global Technologies, LLC (Dearborn, MI)
Patent Number(s):
7,134,273
Application Number:
10/064,957
OSTI ID:
1175983
Country of Publication:
United States
Language:
English

References (1)

Urea-SCR: a promising technique to reduce NOx emissions from automotive diesel engines journal June 2000

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