Abstract: An exhaust catalytic converter for a Diesel engine that provides for enrichment of the Diesel engine exhaust with hydrocarbons that support nitrogen oxide conversion in the catalyst. The system includes a first catalytic converter stage that is designed for NOx conversion in a first temperature range utilizing a first part of the HC enrichment volume in the exhaust and has a suitable first catalyst material charge for the purpose as well as a second catalytic converter stage that follows the first in the exhaust flow direction, the second stage being designed for NOx conversion in a second temperature range higher than the first and utilizing a second part of the HC enrichment volume in the exhaust, and containing a second catalyst material charge suitable for the purpose. By suitably tuning the system with HC enrichment, reduction of emissions of solid and volatile particles in the Diesel exhaust can be achieved.

Abstract: An exhaust-gas filter, for example a soot-particle filter, has a filter element which has inlet passages for the raw gas and outlet passages for the clean gas. In order as far as possible to prevent clogging of the filter over the running time caused by deposits on the filter walls, the raw-gas passages are configured with a larger cross-section than the clean-gas passages.

Abstract: An exhaust gas filter for Diesel engines that consists of a monolithic filter block made of a porous ceramic material having a plurality of ducts extending in the flow direction of the exhaust gases, said ducts alternately being closed by plugs in order to force the passage of gas through the duct walls into adjacent ducts. In the case of this exhaust gas filter, the filter block is divided into zones having a decreasing porosity in the flow direction of the gases, and the plugs which force the passage of the gas through the duct walls are each arranged in the area of the zone border. Filters are preferred that have two to four zones of decreasing porosity. The exhaust gas filters are manufactured in that a filter blank that has the largest desired porosity is immersed in a solution or suspension of a porosity-reducing agent up to the desired zone border and is subsequently dried and is possibly burnt. Preferred agents for reducing the porosity are water glass solutions or cordierite suspensions.

Abstract: An exhaust gas filter for Diesel engines that consists of a filter block made of a porous ceramic material, and a plurality of ducts extending through said filter block that extend in the flow direction of the exhaust gases. The ducts in each case are alternately closed at their upstream or their downstream end, whereby the exhaust gases are forced to penetrate a filtering separating wall between two ducts. The closing means at the downstream end, are arranged so that they are staggered with respect to one another in the flow direction; in particular they are staggered by about 5 to 150 mm. The staggered arrangement of the closing means reduces the danger of a thermal damage to the filter block during the burning-off of the deposited soot.