Method and system using a filter for treating exhaust gas having particulate matter
AssigneeJohnson Matthey Public Limited Company
InventorsLouise Clare Arnold, Robert James Brisley, Christopher Gough Morgan
Life of this patent
Estimating the term…
Abstract
A filter for filtering particulate matter (PM) from exhaust gas emitted from a positive ignition engine or a compression ignition engine, which filter comprising a porous substrate having inlet surfaces and outlet surfaces, wherein the inlet surfaces are separated from the outlet surfaces by a porous structure containing pores of a first mean pore size, wherein the porous substrate is coated with a washcoat comprising a plurality of solid particles wherein the porous structure of the washcoated porous substrate contains pores of a second mean pore size, and wherein the second mean pore size is less than the first mean pore size.
Claims34
A system for filtering particulate matter from exhaust gas, said system comprising:
- a filter having inlet surfaces, outlet surfaces, and a porous structure between the inlet surfaces and the outlet surfaces;
- a selective catalytic reduction (SCR) washcoat comprising a small pore zeolite promoted with at least one metal selected from the group consisting of Cr, Co, Cu, Fe, Hf, La, Ce, In, V, Mn, Ni, Zn, Ga, Ag, Au, Pt, Pd, and Rh, wherein the washcoat is disposed:
- on the inlet surfaces, on the outlet surfaces, or within the porous structure and provides a washcoated filter for filtering the particulate matter;
- and wherein the porous structure has substrate pores of a first mean pore size;
- the washcoat defines pores of a second mean pore size;
- and the second mean pore size is less than the first mean pore size, and;
- a NOx absorber catalyst disposed upstream of the washcoat.
A method for trapping particulate matter from exhaust gas emitted from an engine, said method comprising:
- contacting the exhaust gas containing the particulate matter with a NOx absorber catalyst, then directing the exhaust gas across a filter having inlet surfaces, outlet surfaces, and a porous structure between the inlet surfaces and the outlet surfaces, wherein a selective catalytic reduction (SCR) washcoat comprising a small pore zeolite promoted with at least one transition metal selected from the group consisting of Cr, Co, Cu, Fe, Hf, La, Ce, In, V, Mn, Ni, Zn, Ga, Ag, Au, Pt, Pd, and Rh is disposed:
- on the inlet surfaces, on the outlet surfaces, or within the porous structure and provides a washcoated filter for filtering the particulate matter and wherein the porous structure has substrate pores of a first mean pore size;
- the washcoat defines pores of a second mean pore size;
- and the second mean pore size is less than the first mean pore size.
A filter for filtering particulate matter (PM) from an exhaust gas, the filter comprising:
- a filter substrate having inlet surfaces, outlet surfaces, and a porous structure between the inlet surfaces and the outlet surfaces, wherein the porous structure has substrate pores of a first mean pore size;
- and
- a selective catalytic reduction (SCR) washcoat comprising a small pore zeolite promoted with at least one metal selected from the group consisting of Cr, Co, Cu, Fe, Hf, La, Ce, In, V, Mn, Ni, Zn, Ga, Ag, Au, Pt, Pd, and Rh, wherein (a) the washcoat is disposed within the porous structure and optionally on at least one of the inlet surfaces and the outlet surfaces, and provides a washcoated filter for filtering the particulate matter, (b) the washcoat defines pores of a second mean pore size, and the second mean pore size is less than the first mean pore size, and (c) the washcoat has a mean particle size of about 1 to 18 μm and/or a D90 particle size of about 1 to 18 μm.
Dependencies are inferred from the claim text.