Abstract: A double pipe exhaust manifold includes an inner pipe, an outer pipe formed in a cylindrical shape by joining at least one side edge thereof by welding, a space retaining member disposed in an annular space defined between the inner pipe and the outer pipe, a connection pipe connecting to a exhaust gas recirculation valve, and a mesh ring. Opening holes are formed in the inner pipe and the outer pipe so that the opening holes are opposed to each in a radial direction of the pipes. The connection pipe is connected to the opening hole of the outer pipe. The mesh ring is interposed between the inner pipe and the outer pipe in a state that the mesh ring plugs an annular opening part defined between opening edges of the opening holes.

Abstract: Disclosed is a double pipe exhaust manifold having an inner pipe, a mesh spacer member applied to the outer periphery of the inner pipe, and an outer pipe being disposed around the outer periphery of the mesh spacer member in a state that the outer pipe is axially slidable at least to the inner pipe, wherein the outer pipe is divided into two pipe members, and one side end of one of the divided pipe members is put on the corresponding one of the other of the divided pipe members as radially viewed, and the other side end of the divided pipe member is put on the corresponding one of the latter divided pipe member, and the overlapping portions are welded together.

Abstract: A double pipe exhaust manifold includes an inner pipe, an outer pipe formed in a cylindrical shape by joining at least one side edge thereof by welding, a space retaining member disposed in an annular space defined between the inner pipe and the outer pipe, a connection pipe connecting to a exhaust gas recirculation valve, and a mesh ring. Opening holes are formed in the inner pipe and the outer pipe so that the opening holes are opposed to each in a radial direction of the pipes. The connection pipe is connected to the opening hole of the outer pipe. The mesh ring is interposed between the inner pipe and the outer pipe in a state that the mesh ring plugs an annular opening part defined between opening edges of the opening holes.

Abstract: Disclosed is a double pipe exhaust manifold having an inner pipe, a mesh spacer member applied to the outer periphery of the inner pipe, and an outer pipe being disposed around the outer periphery of the mesh spacer member in a state that the outer pipe is axially slidable at least to the inner pipe, wherein the outer pipe is divided into two pipe members, and one side end of one of the divided pipe members is put on the corresponding one of the other of the divided pipe members as radially viewed, and the other side end of the divided pipe member is put on the corresponding one of the latter divided pipe member, and the overlapping portions are welded together.

Abstract: A method of making a catalytic converter for an automotive internal combustion engine comprises a cylindrical honeycomb catalyst carrier made of a ceramic and carrying a catalytic material. The catalyst carrier is encased within a cylindrical container upon being axially supported at its opposite end faces between oppositely disposed annular metal caps through cushioning materials. The metal caps are fixedly secured to the inner peripheral surface of the container by plug welding. In production of the catalytic converter, the plug welding is made in a state in which the metal caps are being biased to the catalyst carrier at a predetermined pressure by a pair of pressing jigs which respectively abut the metal caps.