A catalytic converter with excellent OSC performance and No.sub.x purification performance. The catalytic converter includes a substrate with a cell structure and a catalyst layer formed on a cell wall surface of the substrate. The catalyst layer has a catalyst layer arranged on the upstream side and a catalyst layer arranged on the downstream side in an exhaust gas flow direction on the substrate. The catalyst layer on the upstream side includes a support containing an Al.sub.2O.sub.3—CeO.sub.2—ZrO.sub.2 ternary composite oxide (ACZ material) and an Al.sub.2O.sub.3—ZrO.sub.2 binary composite oxide (AZ material), and at least Rh that is a noble metal catalyst carried on the support, and the catalyst layer on the downstream side includes a support and Pd or Pt that is a noble metal catalyst carried on the support. In the support in the catalyst layer on the upstream side, the mass proportion of ACZ material/(ACZ material+AZ material) is in the range of 0.33 to 0.5, and greater than or equal to 75% mass Rh is carried on the Al.sub.2O.sub.3—ZrO.sub.2 binary composite oxide of the support.

A catalysed filter for a positive ignition internal combustion engine comprises a porous filtering substrate having a total substrate length coated with a three-way catalyst washcoat composition comprising at least one precious metal selected from the group consisting of rhodium and one or both of platinum and palladium supported on a high surface area oxide, and an oxygen storage component, which composition being axially shared by a first zone comprising inlet surfaces of a first substrate length<total substrate length and a second zone comprising outlet surfaces of a second substrate length<total substrate length, wherein a sum of the substrate length in the first zone and the substrate length in the second zone≧100% and wherein one or both of the following applies: a washcoat loading in the first zone>second zone; and a total precious metal loading in the first zone>second zone.

The risk of a particulate filter from being damaged is reduced while an increase in pressure loss of the particulate filter due to ash is suppressed. Micropore zones are defined at upstream sides of partition walls of a particulate filter and macropore zones are defined at downstream sides of partition walls. The pore size of the partition walls at the micropore zones is set so that the particulate matter and the ash can be trapped by the partition walls at the micropore zones, while the pore size of the partition walls at the macropore zones is set so that the ash can pass through the partition walls at the macropore zones. When the difference dQPM between the quantity of the particulate matter which is trapped at the micropore zones and the quantity of particulate matter which is trapped at the macropore zones exceeds a predetermined threshold value, PM removal control is executed.

A catalyst article having an extruded support having a plurality of channels through which exhaust gas flows during operation of an engine, and a single layer coating or a bi-layer coating on the support, where the extruded support contains a third SCR catalyst, the single layer coating and the bilayer-coating contain platinum on a support with low ammonia storage and a first SCR catalyst. The catalytic articles are useful for selective catalytic reduction (SCR) of NOx in exhaust gases and in reducing the amount of ammonia slip. Methods for producing such articles are described. Methods of using the catalytic articles in an SCR process, where the amount of ammonia slip is reduced, are also described.

The invention relates to a particle filter (1) for an exhaust gas system (2), and to a method for producing a particle filter. The particle filter (1) comprises a plurality of flow channels (5), which extend from a first end face (6) towards a second end face (7) and which are separated from one another by porous channel walls (8). On the end faces (6, 7), the flow channels (5) each have mutual closing means (9) such that an exhaust gas (10) enters a flow channel (5) that is open on the first end face (6), flows through the channel wall (8), and escapes from the particle filter (1) by way of an adjacent flow channel (5) that is open on the second end face (7). In a direction of flow (11), the channel wall (8) has, in succession, the following layers: a particle filter layer (13); an intermediate layer (14) comprising a first SCR coating (15) having a first catalytic activity (16); a second SCR coating (18) having a second catalytic activity (19), wherein the second catalytic activity (19) is different from the first catalytic activity (16).

The present invention is directed to a process for the production of exhaust catalysts. In particular, the process describes a way of coating a substrate in a manner which finally leads to reduced coating times.

A particulate filter (1) is provided having a first wall flow region (2) and a second flow through region (3). The filter is provided with a catalytic washcoat, whereby the filter can be used to remove both particulate matter and harmful gaseous emissions from an exhaust gas stream.

In an EHC, a ratio of a heat capacity of the second catalyst body with respect to a heat capacity of the first catalyst body is made within a range of 0.67-1.5. A ratio of an amount of coat of an OSC material in the second catalyst body with respect to an amount of coat of an OSC material in the first catalyst body is made larger than the ratio of the heat capacity of the second catalyst body with respect to the heat capacity of the first catalyst body. A ratio of an amount of support of a noble metal in the second catalyst body with respect to an amount of support of a noble metal in the first catalyst body is made smaller than the ratio of the heat capacity of the second catalyst body with respect to the heat capacity of the first catalyst body.

The invention relates to a device for generating ammonia from an ammonia precursor solution, having a reaction space with an inflow connector through which an exhaust-gas flow can flow into the reaction space, having an outflow connector through which an ammonia-containing gas flow can exit the reaction space, and having a supply device by way of which selectively an ammonia precursor solution or a fuel can be supplied into the reaction space.

Provided is a particulate filter in which a PM collection rate is stably increased. The particulate filter according to the present invention includes a substrate 10 having a wall flow structure having a porous partition wall 16 that partitions an inlet cell and an outlet cell, and a wash coat layer held on surfaces of internal pores of the partition wall. In addition, average filling rates A, B, and C of the wash coat layer measured for each predetermined pore diameter range in the internal pores satisfy specific relationships. Further, the wash coat layer is formed in a region that occupies 50% or more of a thickness of the partition wall, and an amount of a noble metal catalyst carried by the wash coat layer is 0 g/L or more but 0.2 g/L or less.