Abstract: A wall-flow filter (10) for an exhaust system of a combustion engine comprises: a plurality of channels (4,6,8) in honeycomb arrangement, wherein at least some of the channels (6) are plugged (12) at an upstream end and at least some of the channels (4,8) not plugged at the upstream end are plugged (14) at a downstream end; an oxidation catalyst (16) on a substantially gas impermeable zone at an upstream end of the channels (4,8) plugged at the downstream end; and a gas permeable filter zone (22) downstream of the oxidation catalyst for trapping soot, characterised in that in an exhaust system, preferably a diesel exhaust system, the oxidation catalyst is capable of generating sufficient NO2 from NO to combust the trapped soot continuously at a temperature less than 400° C.

Abstract: An exhaust gas treatment system (8) for a diesel engine (10) having a NOx absorber (28) charged with solid absorbent for absorbing NOx from a diesel exhaust gas and means (18) for introducing intermittently into the exhaust system CO upstream of said absorber (28) whereby the solid absorbent is regenerable by contact with the CO-enriched gas. A process for treating NOx in a diesel exhaust gas comprises absorbing the NOx in a solid absorbent and regenerating the absorbent by contacting it with CO-enriched gas.

Abstract: A wall-flow filter (10) for an exhaust system of a combustion engine comprises: a plurality of channels (4,6,8) in honeycomb arrangement, wherein at least some of the channels (6) are plugged (12) at an upstream end and at least some of the channels (4,8) not plugged at the upstream end are plugged (14) at a downstream end; an oxidation catalyst (16) on a substantially gas impermeable zone at an upstream end of the channels (4,8) plugged at the downstream end; and a gas permeable filter zone (22) downstream of the oxidation catalyst for trapping soot, characterised in that in an exhaust system, preferably a diesel exhaust system, the oxidation catalyst is capable of generating sufficient NO2 from NO to combust the trapped soot continuously at a temperature less than 400° C.

Abstract: A wall-flow filter for an exhaust system of a combustion engine comprises: a plurality of channels in honeycomb arrangement, wherein at least some of the channels are plugged at an upstream end and at least some of the channels not plugged at the upstream end are plugged at a downstream end; an oxidation catalyst on a substantially gas impermeable zone at an upstream end of the channels plugged at the downstream end; and a gas permeable filter zone downstream of the oxidation catalyst for trapping soot, in that in an exhaust system, preferably a diesel exhaust system, the oxidation catalyst, which preferably includes a platinum group metal, is capable of generating sufficient NO2 from NO to combust the trapped soot continuously at a temperature less than 400° C.

Abstract: An exhaust gas treatment system (8) for a diesel engine (10) comprises a NOx absorber (28) charged with solid absorbent for absorbing NOx from a diesel exhaust gas and means (18) for introducing intermittently into the exhaust system CO upstream of said absorber (28) whereby the solid absorbent is regenerable by contact with the CO-enriched gas. A process for treating NOx in a diesel exhaust gas comprises absorbing the NOx in a solid absorbent and regenerating the absorbent by contacting it with CO-enriched gas.

Abstract: An emission control system especially for light duty diesel engines has a first catalyst, 2, positioned upstream of a second catalyst, 3. The first catalyst converts NO to NO2 and the second catalyst oxidises HC, CO and VOF. The tendency of the second catalyst to collect soot particles is reduced by combustion of the soot particles by NO2 from the first catalyst.