Method for manufacturing an exhaust gas treatment device
A method for manufacturing an exhaust gas treatment device for an internal combustion engine comprises axially inserting an exhaust gas treatment cartridge into a casing, wherein the casing has an initial inside cross-section that is larger than an outside cross-section of the exhaust gas treatment cartridge. A funnel is axially inserted into an end region of the casing, wherein an outside cross-section of the funnel is smaller than the initial inside cross-section of the casing. The cross-section of the casing is subsequently reduced such that the casing ultimately has a first ultimate inside cross-section that is equal to the outside cross-section of the exhaust gas treatment cartridge in a region, in which the at least one exhaust gas treatment cartridge is arranged, and a second ultimate inside cross-section that is equal to the outside cross-section of the funnel in the respective end region, in which the respective funnel is arranged.
1. A method for manufacturing an exhaust gas treatment device for an internal combustion engine of a motor vehicle, comprising the steps of:
axially inserting at least one exhaust gas treatment cartridge into a cylindrical casing that is open on at least one side, wherein the casing has an initial inside cross-section larger than an outside cross-section of the exhaust gas treatment cartridge;
axially inserting at least one funnel into an axial end region of the casing, the at least one funnel comprising a first end region of a first outside cross-section and a second end region having a tapered outside cross-section, the first end region of the at least one funnel being proximal to the at least one exhaust gas treatment cartridge, and wherein the first outside cross-section of the first end region of the funnel is smaller than the initial inside cross-section of the casing; and,
reducing the cross-section of the casing such that the casing subsequently has a first ultimate inside cross-section equal to the outside cross-section of the exhaust gas treatment cartridge in a first region of the casing in which the at least one exhaust gas treatment cartridge is arranged, and a second ultimate inside cross-section equal to the first outside cross-section of the first end region of the funnel in a second end region of the casing in which the funnel is arranged, wherein both of the outside cross-section of the at least one exhaust gas treatment cartridge and the first outside cross-section of the first end region of the at least one funnel are reduced during the reducing step.
2. The method according to claim 1 , wherein the at least one exhaust gas treatment cartridge comprises at least one of a catalytic converter element and a particle filter element.
3. The method according to claim 2 , wherein the catalytic converter element or the particle filter element comprises a ceramic monolith.
4. The method according to claim 3 , wherein at least one of the casing and the at least one funnel comprises sheet metal.
5. The method according to claim 1 , wherein:
the first outside cross-section of the first end region of the funnel is smaller or larger than the outside cross-section of the at least one exhaust gas treatment cartridge before said reducing; and
the first outside cross-section of the first end region of the funnel is equal to or smaller or larger than the outside cross-section of the at least one exhaust gas treatment cartridge after the reduction in cross-section.
6. The method according to claim 1 , wherein the second ultimate inside cross-section of the casing is smaller or larger than the first ultimate inside cross-section of the casing in the second region of the casing after the reducing.
7. The method according to claim 1 , further comprising the step of: radially clamping at least one of the at least one exhaust gas treatment cartridge and at least one funnel in position during the reducing.
8. The method according to claim 1 , wherein the at least one exhaust gas treatment cartridge comprises a cartridge body and a supporting mat that is circumferentially wrapped around the cartridge body, wherein the supporting mat is radially compressed during the reducing.
9. The method according to claim 1 , further comprising the step of at least one of welding and soldering the first end region of the at least one funnel to the casing after the reducing.
10. The method according to claim 1 , wherein the reducing in cross-section comprises rolling the casing about its longitudinal axis under a radial compressive load.
11. The method according to claim 1 , wherein the reducing in cross-section comprises radially compressing the casing using circumferentially distributed pressure segments.
12. The method of claim 1 , further comprising the step of maintaining an axial separation between the at least one exhaust gas treatment cartridge and the first end region of the at least one funnel.
13. The method of claim 1 , wherein the second end region is connected to the first end region, and wherein at least a portion of the tapered outside cross-section of the second end region extends out of the casing.
14. The method of claim 1 , wherein the tapered outside cross-section of the second end region has a progressively decreasing outside cross-section in the direction extending outward from the casing.