Exhaust gas filter for diesel engines

US4704863A · kind A · utility

Assignee

• Daimler-Benz AG · DE

Inventors

• Joerg Abthoff · Schorndorf, DE
• Hans-Dieter Schuster · Schorndorf, DE
• Gunter Loose · Waiblingen, DE
• Bernhard Jokl · Bad Liebenzell, DE

Key dates

• Filing date: Dec 19, 1985
• Grant date: Nov 10, 1987
• Expiry date: Dec 19, 2005

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S55/30
• WIPO field: Chemical engineering
• WIPO sector: Chemistry

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.