Patent ID: 8641134

Claim:
A method of making an air duct for an automotive vehicle, comprising the steps of: providing an elongated, hollow structural member for a portion of a body of the vehicle, wherein the structural member has an inner wall defining an elongated cavity communicating with first and second access holes at respective longitudinal positions along the structural member; inserting a parison into the internal cavity, wherein the parison is comprised of a thermally insulating material and has a bladder portion and a mouth portion; connecting a source of inflation gas to the mouth portion; heating and inflating the parison within the internal cavity to an expanded shape constrained by the inner wall to form the air duct disposed against the inner wall and spanning the first and second access holes, wherein the expanded shape is retained upon cooling; configuring the air duct at one of the access holes as an air inlet; and configuring the air duct at the other one of the access holes as an air outlet.