Abstract: An internal reinforcement structure of a plastic fuel tank resists deformation of opposing walls of the fuel tank and provides an integral, and directionally sensitive, stress relief feature when pre-determined forces are exceeded. The stress relief feature is contained within a fuel chamber of the fuel tank defined by the opposing walls. Each wall has an inward projecting indentation of the structure which engage one-another at their distal ends or bottom portions, preferably, via a welded plastic engagement area. The indentations have a consistent wall thickness which has a higher cross-sectional area than the stress relief feature causing the stress relief feature to tear as opposed to the tank walls thereby assuring fuel tank integrity.

Abstract: A fuel container with a wall of at least two wall shells which are separated at least partially from each other by an air gap between them. The dual shell wall structure helps to substantially improve the mechanical properties of the fuel container. Preferably, each wall shell consists of a plurality of layers of different polymeric or plastic materials. In a preferred embodiment of the invention a four layer co-extruded structure is provided; each shell comprises a layer of high density polyethylene (HDPE), a layer of filler material of treated, recycled plastics material referred to as “re-grind” and a vapor barrier layer of a plastic material substantially impermeable by hydrocarbons. The HDPE-layer may, be one surface layer of each wall shell and the vapor barrier layer is preferably the other surface layer of each wall shell. Depending on the material properties of the vapor barrier layer, an additional adhesive layer may also be necessary for connection with the adjacent layer.

Abstract: A fuel tank has a plurality of fuel system components therein and is formed by incorporating the fuel system components into the fuel tank as it is being formed. The fuel system components may be mounted on a carrier and then disposed with the carrier within a parison subsequently molded to form the fuel tank around the components and carrier. Desirably, all electrical, fuel and vapor lines may extend out of a single opening of the fuel tank to reduce openings in the formed fuel tank.

Abstract: A method of forming multi-walled plastic containers in a single blow mold. In general, the method comprises disposing at least two separate parisons simultaneously into a blow mold and forming them to shape one after another by means of a special blow mandrel or pin. A substantially hollow, cylindrical first parison may be disposed around or outside of a substantially balloon or tube shaped second parison in an initially open blow mold. After closing the blow mold, the first or outer parison is expanded outwardly so that its outer surface engages the inner surface of the blow mold to assume the shape thereof, and thereafter, the second or inner parison is blown or outwardly expanded to an extent such that its outer surface at least partially engages the inner surface of the first or outer parison. The outer and inner parisons may be formed of different materials which may desirably impart different properties such as mechanical stability and resistance to permeation of fuel vapor from the container.

Abstract: A device for mounting a plastic fuel tank on the body of a motor vehicle with a carrier which is shaped to fit at least partially to the outer contour of the tank and at least one coupling disposed between the carrier and the tank. The coupling is releasably connected with a snap fit to the carrier and preferably is made of a thermoplastic material that is heat welded to the plastic tank.

Abstract: A cover element and clamping ring are mountable on and sealable to close a tubular portion surrounding an access opening in a wall portion of a container of a fuel tank assembly for a motor vehicle. The tubular portion is contiguous with and projects outward from the wall portion, defines the opening in the wall portion, and has a contoured bead which projects radially outward from the projected end of the tubular portion. The cover element is demountably situated on the projected end of the tubular portion and is thereby removably situated over the opening in the container. A sealing ring is removably disposed between the cover element and the tubular portion of the container. The clamping ring is removably snapped onto the contoured bead of the tubular portion of the container.