Patent ID: 6427440
Filing Date: 2002-08-06
Classification: F01N

Abstract:
An airgap-insulated exhaust manifold of an exhaust system of a motor vehicle, comprising:at least two exhaust pipes each having an inlet flange attached to one end and to be fastened to a cylinder head of an internal combustion engine of the motor vehicle, the exhaust pipes comprising a pipe bend and at least one branched pipe piece connected to the pipe bend; at least one exhaust pipe having an inner pipe and an outer pipe, with airgap insulation provided between the inner pipe and outer pipe, the inner pipe and outer pipe formed from rectilinear double pipe by fluid at high pressure so that a gap is formed between the inner pipe and outer pipe, the gap being continuous without obstruction between distal ends of the inner pipe and the outer pipe; and at least one exhaust pipe without an air insulation gap, the outer pipe and the inner pipe of the airgap-insulated exhaust pipe bearing against one another at an end which is plugged together with and welded to the associated inlet flange, at least the exhaust pipe without an air insulation gap being welded at one end to an individual inlet flange, and the exhaust pipe without an air insulation gap, at an end facing away from the inlet flange, being plugged together with and welded to the outer pipe of an airgap-insulated exhaust pipe.