Dual-layer to flange welded joint

1. A dual wall exhaust manifold comprising:

a flange;

an inner assembly having a plurality of runners for transporting engine exhaust gases from an inlet to an outlet of the inner assembly, the outlet or the inlet of the inner assembly being connected to the flange;

an outer shell enclosing the inner assembly and spaced apart from the inner assembly, the outer shell having an end portion;

at least one outwardly facing notch in the outer shell, the notch defined by the flange, the inner assembly, and the outer shell end portion; and

a single weld located along the notch to interconnect the flange, the inner assembly and the outer shell.

2. The dual wall exhaust manifold of claim 1 wherein the weld extends along the entire perimeter of the outer shell end portion.

3. The dual wall exhaust manifold of claim 2 wherein the flange includes a bore for receiving the inner assembly.

4. The dual wall exhaust manifold of claim 3 wherein inner assembly is slip fit into the bore, the slip fit allowing for thermal expansion of the inner assembly.

5. The dual wall exhaust manifold of claim 4 wherein the inner assembly is formed from an upper portion and a lower portion.

6. The dual wall exhaust manifold of claim 5 wherein the upper portion and a lower portion are welded together.

7. The dual wall exhaust manifold of claim 4 wherein the outer shell is formed from an upper portion and a lower portion.

8. The dual wall exhaust manifold of claim 1 wherein the notches are equidistantly spaced around the entire perimeter of the outer shell end portion.

9. The dual wall exhaust manifold of claim 8 wherein each notch includes a single weld to interconnect the flange, the inner assembly and the outer shell.