Abstract: The invention relates to a connecting piece (6) for fluid lines of an exhaust gas aftertreatment system (1), comprising a hollow body (6a) having at least three fluid connection points (14, 15), which are fluidically connected to each other in the hollow body (6a), at least two of the fluid connection points (15) being separated from a third fluid connection point (14) by means of respective membranes (19), each membrane (19) being permeable to a liquid and, when wetted by the liquid, being impermeable to a gas.

Abstract: The invention relates to a connecting piece (6) for fluid lines of an exhaust gas aftertreatment system (1), comprising a hollow body (6a) having at least three fluid connection points (14, 15), which are fluidically connected to each other in the hollow body (6a), at least two of the fluid connection points (15) being separated from a third fluid connection point (14) by means of respective membranes (19), each membrane (19) being permeable to a liquid and, when wetted by the liquid, being impermeable to a gas.

Abstract: A method for operating a reagent dosing system (12), in which at least one dosing valve (14) doses a reagent upstream of at least one SCR catalytic converter (16) which is arranged in an exhaust-gas duct of an internal combustion engine (10), in which method the reagent, which is stored in a tank (28), is heated by means of a heater (30), and in which method a cavity (44) in the region of the heater (30) is detected on the basis of the evaluation of a characteristic variable of a measure of the heating current (32). The approach according to the invention is characterized in that, in the event of a cavity (44) being detected, a notification signal (52) is provided.

Abstract: Cross-sectional geometries of filter elements for soot particle filters are described, allowing uniform loading of the filter element with soot. Starting with hexagonal cell shapes, other polygonal shapes are arranged around them. All the cross-sectional geometries have in common the fact that the cross-sectional area of all inlet channels is larger than the cross-sectional area of all outlet channels.

Abstract: A fluid filter has a plurality of inlet channels, a plurality of outlet channels, and filter walls separating the inlet channels from the outlet channels. The inlet channels are parallel to the outlet channels, and the filter walls have a plurality of pores through which the inlet channels are connected to the outlet channels. A cross-sectional area of all inlet channels is larger than a cross-sectional area of all outlet channels, and a value of diameters of the pores of the filter walls calculated by mercury porosimetry being a median value d50, being between 0.01 ?m and 0.5 ?m.

Abstract: A filter element, especially for filtering exhaust gases of an internal combustion engine, having inlet channels that are open at the input end and closed at the output end in the flowthrough direction, and having outlet channels that are closed at the input end and open at the output end in the flowthrough direction, the inlet channels and outlet channels being delimited by filter walls, the profile of at least some of the filter walls of an outer region of the filter element being adapted to the profile of an at least locally curved outer side of the filter element.

Abstract: Cross-sectional geometries of filter elements for soot particle filters are described, allowing uniform loading of the filter element with soot. Starting with hexagonal cell shapes, other polygonal shapes are arranged around them. All the cross-sectional geometries have in common the fact that the cross-sectional area of all inlet channels is larger than the cross-sectional area of all outlet channels.