초록 ▼

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 w

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.

대표청구항 ▼

A process for manufacturing an exhaust gas filter for Diesel engines comprising a monolithic filter block made of a porous ceramic material having a plurality of ducts extending in the main flow direction of the exhaust gases from the inlet to the outlet of said filter, said ducts alternately being

A process for manufacturing an exhaust gas filter for Diesel engines comprising a monolithic filter block made of a porous ceramic material having a plurality of ducts extending in the main flow direction of the exhaust gases from the inlet to the outlet of said filter, said ducts alternately being closed by plug means in order to force the passage of the exhaust gas through the duct walls, wherein the filter block is divided into zones, each zone having duct walls with decreased porosity from the previous zone in the main flow direction of the exhaust gases, and wherein additional plug means are arranged in the area of the border of the zones in such a way that the exhaust gas must flow through the duct walls of more than one zone as said gas flows from the inlet to the outlet of said filter, comprising the steps of: immersing a filter block blank with the largest desired porosity up to the desired zone border in a solution or suspension of a porosity-reducing agent; subsequently drying said filter block blank; immersion and drying process steps being repeated for producing additional zones; and providing the filter block blank with plug at the additional zone borders.