Double walled exhaust duct for motor vehicle, has internal tube partly insulated from body by insulation unit, and orifice for permitting passage of nozzle of fuel diffusion unit e.g. injector, for thermally insulating diffusion unit

摘要

The duct (10) has a body (12), which is cast in a single piece, where the body comprises an internal tube (20) for passage of gas received in the body. The internal tube is partly insulated from the body by an insulation unit (22), which is constituted of an insulation material e.g. aggregate of fibers or microporous element. An orifice (21) permits passage of a diffusion end i.e. nozzle (18), of a fuel diffusion unit (16) e.g. injector, for thermally insulating the diffusion unit. The body is molded from a single block around two tubes (20A, 20B), which are made of thin steel sheet. An independent claim is also included for a method for manufacturing a double walled exhaust duct.