Exhaust gas system

1. An exhaust gas system ( 1 ) for an internal combustion piston engine, comprising:

a manifold ( 2 ) with

several manifold pipes (Z 1 -Z 4 ) and

an exhaust gas fitting ( 2 . 1 ), as well as

an exhaust gas guide element ( 3 ) with an exhaust gas pipe fitting ( 3 . 1 ), which can be connected via the exhaust gas pipe fitting ( 3 . 1 ) to the exhaust gas fitting ( 2 . 1 ),

wherein i) the manifold ( 2 ) and ii) at least the exhaust gas pipe fitting ( 3 . 1 ) of the exhaust gas guide element ( 3 ) each have a partition wall ( 2 . 2 , 3 . 2 ), the partition walls ( 2 . 2 , 3 . 2 ) forming two separate exhaust gas channels (A 2 a , A 2 b , A 3 a , A 3 b ) each with a flow axis (S 2 , S 3 ), and the exhaust gas fitting ( 2 . 1 ) having an end face ( 2 . 2 s ) running transverse to the flow axis (S 2 ), the exhaust gas pipe fitting ( 3 . 1 ) having an end face ( 3 . 2 s ) running transversely to the flow axis (S 2 ),

wherein the exhaust gas fitting end face ( 2 . 2 s ) of the manifold ( 2 ) or at least a first edge segment (R 1 ), a second edge segment (R 2 ) and/or a core segment (K) of the exhaust gas fitting end face ( 2 . 2 s ) at least partially contact the exhaust gas pipe fitting ( 3 . 1 ) in the axial direction at least when the internal combustion piston engine is in a warm state, and

wherein the end face ( 3 . 2 s ) of the exhaust gas pipe fitting ( 3 . 1 ) has a groove ( 3 . 3 ) serving as connection element, of a length ( 13 ), with a groove base ( 3 . 3 G) into which the exhaust gas fitting end face ( 2 . 2 s ) of the partition wall ( 2 . 2 ) of the manifold ( 2 ) can be inserted to join the partition walls ( 2 . 2 , 3 . 2 ), wherein the length ( 13 ) corresponds to an internal diameter (di 3 ) of the exhaust gas pipe fitting ( 3 . 1 ).

2. The exhaust gas system ( 1 ) according to claim 1 , wherein the core segment (K) makes contact with the partition wall ( 3 . 2 ) and/or the first and/or second edge segment (R 1 , R 2 ) makes contact with a bearing surface ( 3 . 1 a ) of the end face of the pipe fitting ( 3 . 1 ).

3. The exhaust gas system ( 1 ) according to claim 1 , wherein the end face ( 2 . 2 s , 3 . 2 s ) has a curved or corrugated profile running in the direction of the flow axis (S 2 , S 3 ) or a geometrical axis (G) with one to ten or more recesses (A 1 , A 2 ), or at least is profiled in configuration.

4. The exhaust gas system ( 1 ) according to claim 1 , wherein the first and second edge segments (R 1 , R 2 ) of the partition wall ( 22 ) lie on the outside in the radial direction in the area of the end face ( 2 . 2 s ), and the core segment K is bounded by the first and second edge segments (R 1 , R 2 ), while the at least one recess (A 1 , A 2 ) is provided between the core segment (K) and the first and second edge segment (R 1 , R 2 ).

5. The exhaust gas system ( 1 ) according to claim 1 , wherein the first and second edge segments (R 1 , R 2 ) have a spacing (aR) and the spacing (aR) corresponds to an internal diameter (di 2 ) of the exhaust gas fitting ( 2 . 1 ).

6. The exhaust gas system ( 1 ) according to claim 1 , wherein the partition wall ( 3 . 2 ) has a width (b 2 ) between 1 mm and 7 mm, at least in the area of the groove ( 3 . 3 ).

7. The exhaust gas system ( 1 ) according to claim 1 , wherein the exhaust gas pipe fitting ( 3 . 1 ) has a housing wall ( 3 . 4 ) with an inner circumference (Ui 3 ) and in one end face of the housing wall ( 3 . 4 ) an indentation ( 3 . 5 ) with a width (b 3 ) is provided, forming a bearing surface ( 3 . 1 a ) and extending in the direction of the flow axis (S 2 , S 3 ) across the inner circumference (Ui 3 ).

8. The exhaust gas system ( 1 ) according to claim 1 , wherein the groove base ( 3 . 3 G) is provided in relation to the flow axis (S 2 , S 3 ) at least partly at the height of the end surface ( 3 . 1 s ) or the bearing surface ( 3 . 1 a ).

9. The exhaust gas system ( 8 ) according to claim 8 , wherein the first and/or second edge segment (R 1 , R 2 ) and/or the partition wall ( 2 . 2 ) and/or the particular half shell ( 2 a , 2 b ) of the exhaust gas fitting ( 2 . 1 ) bears tightly against the bearing surface ( 3 . 1 a ) of the exhaust gas pipe fitting ( 3 . 1 ) in a cold state at the end face inside the indentation ( 3 . 5 ) of the exhaust gas pipe fitting ( 3 . 1 ) in the direction of the flow axis (S 2 , S 3 ).

10. The exhaust gas system ( 1 ) according to claim 1 , wherein the partition wall ( 2 . 2 ) is fashioned thicker than a width (b) of the groove ( 3 . 3 ), while the partition wall ( 2 . 2 ) in the area of the end surface ( 2 . 2 s , 3 . 2 s ) has a flattening ( 2 . 3 ) with a thickness (d), and the thickness (d) is either equal to the width b of the groove ( 3 . 3 ) or smaller than the width b of the groove ( 3 . 3 ).

11. The exhaust gas system ( 1 ) according to claim 10 , wherein the flattening ( 2 . 3 ) has a height (hA) in the direction of the flow axis (S 2 , S 3 ), while the partition wall ( 2 . 2 ) is inserted into the groove ( 3 . 3 ) by 5% to 70% of the height (hA).

12. The exhaust gas system ( 1 ) according to claim 1 , wherein the groove base ( 3 . 3 G) is profiled in the direction of the flow axis (S 2 , S 3 ) or a geometrical axis (G) and/or its profiling matches the profile of the end surface ( 2 . 2 s ).

13. The exhaust gas system ( 1 ) according to claim 1 , wherein there is provided a spacing a between the groove base ( 3 . 3 G) and the end surface ( 2 . 2 s ) of at least 0.1 mm to 0.3 mm in the radial direction to the flow axis (S 2 , S 3 ).

14. The exhaust gas system according to claim 12 , wherein the flattening ( 2 . 3 ) has a height (hA) in the direction of the flow axis (S 2 , S 3 ), while the partition wall ( 2 . 2 ) is inserted into the groove ( 3 . 3 ) by 10% to 50% of the height (hA).

15. The exhaust gas system according to claim 11 , wherein the flattening ( 2 . 3 ) has a height (hA) in the direction of the flow axis (S 2 , S 3 ), while the partition wall ( 2 . 2 ) is inserted into the groove ( 3 . 3 ) by 30% of the height (hA).