Close-coupled scr system
AssigneeJohnson Matthey Public Limited Company
InventorsPaul Richard PHILLIPS, James Alexander WYLIE
Life of this patent
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Abstract
A system for treating exhaust gases from a combustion engine and a method for using the same results in improved NOx conversion during engine startup. The system includes a compact SCR flow-through monolith installed upstream of a close-coupled SCR wall-flow filter, wherein the compact SCR flow-through monolith may be extruded or made of a thin-walled substrate, such that the SCR flow-through monolith has a smaller volume with lower heat capacity and higher catalyst loading relative to the SCR wall-flow filter.
Claims16
A system for treating exhaust gases containing NOx from an engine comprising:
- a flow-through monolith having a first catalytic composition for selective catalytic reduction of NOx;
- a close-coupled particulate matter filter having a second catalytic composition for reduction of particulate matter and selective catalytic reduction of NOx,
- wherein said flow-through monolith is in fluid communication with, and incorporated upstream of, said close-coupled particulate matter filter,
- wherein the flow-through monolith has a volume that is about 15% to about 40% of that of the close-coupled particulate matter filter,
- wherein the first catalytic composition is present on the flow-through monolith at a first loading, the second catalytic composition is present on the close-coupled particulate matter filter at a second loading,
- wherein the system does not comprise an oxidation catalyst upstream of the flow-through monolith, and
- wherein the location of the close-coupled particulate matter filter relative to an upstream turbocharger is such that the exhaust gas travels less than 0.5 meters between the turbocharger and the close-coupled particulate matter filter.
Dependencies are inferred from the claim text.