Device for cleaning exhaust gases

Claim 1

A device for cleaning exhaust gases comprising a ceramic body having rows of walls extending in the direction of a longitudinal axis, opposing ones of the walls and additional longitudinally extending walls defining channels through which the exhaust gases can flow, and electrodes for generating an electric field penetrating the ceramic body and passing through the channels, the electrodes being orientated longitudinally to the longitudinal direction of the channels, the field strength of the electric field in the channels being between 100 and 1000 V/mm, and a characteristic number E, which takes into account the geometry of the cross section of the channels and the specific electric resistance of the material of the ceramic body and which is equivalent to the following relation ##EQU10## being at least 10 7 Ω, wherein ρ constitutes the specific electric resistance of the ceramic material at 600° C. in Ω cm, β constitutes a geometric form factor and d is the width or thickness of the walls separating the channels, the geometric form factor β being a result of the following relation: ##EQU11## wherein l is the average length of the current path formed in the ceramic material between the electrodes and x is the distance between the electrodes measured in the direction of the electric field.

Claim 2

A device for cleaning exhaust gases comprising a ceramic body having rows of walls extending in the direction of a longitudinal axis, opposing ones of the walls and additional longitudinally extending walls defining channels through which the exhaust gases can flow, and electrodes for generating an electric field penetrating the ceramic body and passing through the channels, the electrodes being orientated longitudinally to the longitudinal direction of the channels, the field strength of the electric field in the channels being between 100 and 1000 V/mm, and a characteristic number E, which takes into account the geometry of the cross section of the channels and the specific electric resistance of the material of the ceramic body and which is equivalent to the following relation ##EQU10## being at least 10 7 Ω, wherein ρ constitutes the specific electric resistance of the ceramic material at 600° C. in Ω cm, β constitutes a geometric form factor and d is the width or thickness of the walls separating the channels, the geometric form factor β being a result of the following relation: ##EQU11## wherein l is the average length of the current path formed in the ceramic material between the electrodes and x is the distance between the electrodes measured in the direction of the electric field.

Claim 11

A device for removing soot particles from exhaust gases of an internal combustion engine, which comprises (a) a ceramic body defining an ionization chamber for generating negative ions and arranged to receive the exhaust gases and to permit the exhaust gases to flow therethrough, (1) the ceramic body having walls defining separation channels disposed substantially parallel to the ionization chamber, (b) electrode means projecting into the ionization chamber and arranged to generate at least one electric field extending transversely to the direction of flow of the exhaust gases, and (c) means for deflecting the flow of the exhaust gases as they flow out of the ionization chamber and reversing the direction of flow to direct the exhaust gases into the separation channels, the soot particles being deposited on the walls of the separation channels and being burned off by the electric field.

Claim 12

A device for removing soot particles from exhaust gases of an internal combustion engine, which comprises (a) a ceramic body defining an ionization chamber for generating negative ions and arranged to receive the exhaust gases and to permit the exhaust gases to flow therethrough, (1) the ceramic body having walls defining separation channels disposed substantially parallel to the ionization chamber, (b) electrode means projecting into the ionization chamber and arranged to generate at least one electric field extending transversely to the direction of flow of the exhaust gases, and (c) means for deflecting the flow of the exhaust gases as they flow out of the ionization chamber and reversing the direction of flow to direct the exhaust gases into the separation channels, the soot particles being deposited on the walls of the separation channels and being burned off by the electric field.