US 8,066,963 B2 · Removal of particulates from the exhaust gas of internal combustion engines operated with a predominantly stoichiometric air/fuel mixture

Abstract

The exhaust gas of internal combustion engines operated with a predominantly stoichiometric air/fuel mixture contains, as well as the gaseous hydrocarbon (HC), carbon monoxide (CO) and nitrogen oxide (NOx) pollutants, also ultrafine particulates. There is disclosed a catalytically active particulate filter, an exhaust gas cleaning system and a process for cleaning the exhaust gases of predominantly stoichiometrically operated internal combustion engines, as well as the gaseous CO, HC and NOx pollutants, also for removing particulates from the exhaust gas. The particulate filter comprises a filter body and a catalytically active coating consisting of two layers. Both layers contain alumina. The first layer contains palladium. The second layer contains rhodium. The latter is disposed above the first layer.

Claims10

Dependent claims

An exhaust gas cleaning system for cleaning the exhaust gases of internal combustion engines operated with a predominantly stoichiometric air/fuel mixture, comprising:

a particulate filter comprising a filter body,
a first catalytically active layer, which comprises alumina and palladium and is free of oxygen-storing cerium/zirconium mixed oxides, layered on and in direct contact with the filter body, and
a second catalytically active layer, which comprises alumina, rhodium and an oxygen-storing cerium/zirconium mixed oxide, completely covering the first catalytically active layer on its exhaust gas side,
wherein the palladium and the rhodium are spatially separated, and
wherein the catalytically active particulate filter is disposed in a position close-coupled to the engine.

2 more elements

Dependencies are inferred from the claim text.

Removal of particulates from the exhaust gas of internal combustion engines operated with a predominantly stoichiometric air/fuel mixture

Life of this patent

Removal of particulates from the exhaust gas of internal combustion engines operated with a predominantly stoichiometric air/fuel mixture

Life of this patent

Abstract

Claims10