8 but approximately 90 degrees of angular section is saved as shown in the lower part of the figure it means that the sleeve 8 is supported at its outer surface 7 along its entire length within this section of approximately 90 degrees the sleeve is thus having a particularly good support in this section it also means that the catalytic converter element is in principle shut off in this section a wart 23 is arranged in the duct 35 in the partition wall the wart 23 is thus arising from the duct 35 adjacent the adapted depression 15 it supports the outer surface 7 a corresponding wart 24 is arranged in the cover plate 18 it is placed in a position corresponding to the wart 23 and the both warts are almost reaching each other it means that the sleeve 8 is supported along its entire length on the one hand at the previously mentioned section downwards in the fig1 and 2 and on the other hand at the warts 23 and 24 as for the rest the both end surfaces are kept fixed in that they are immersed into the adapted depressions 15 16 the cleaned exhaust gases 4 are flowing out into the ducts 34 35 an outlet opening 22 connects to the duct 35 this outlet opening is embodied as a collared hole in which an outlet pipe 11 is connected the cleaned exhaust gases 4 are thus flowing out through the outlet opening 22 and through the outlet pipe 11 the other end of the outlet pipe 11 is connected to an aperture 36 which is arranged on the upper side of the rear housing 9 the cleaned exhaust gases are conducted through an exhaust gas outlet 37.