Investigating the Feasibility of a Composite Under Hood Engine Component

Abstract

During the summer of 1998, I worked at Siemens Automotive in Auburn Hills, :MI. Siemens Automotive is a smaller division of the Siemens Corporation. Siemens Automotive designs and manufactures automobile parts for the automotive industry. The division I worked in was Powertrain / Air Induction. This group is involved primarily with air intake manifolds, air cleaners and throttle bodies. In addition, the emphasis is on the use of composite materials, especially plastic, in the design and production of these components. Plastics, especially Nylons, are being used extensively in the automotive industry because of their light weight, nonconducting characteristics and ease of recycling. Furthermore, plastic parts are, in many instances, cheaper than their metal counter-parts. Plastics are available in many types and can have such things as glass or minerals added to them to change their properties, especially strength. Molding of plastics occurs in several ways. The three primary methods are injection molding, blow molding and extrusion. Furthermore, once parts are molded, many times, they need to be assembled. This is done primarily by snap fitting or vibration welding. Snap fitting involves two or more parts which secure together by some sort of fastener. Vibration welding utilizes machines to rub two plastic pieces together at many times per second. This causes the plastic at the surfaces being rubbed to melt and bond together. Also, when a part is needed which cannot be snap fit or vibrated together, the lost core process is used. With lost core, a metal core of Tin-Bismuth is first molded. Then, the nylon is injected over the metal core. Next, the part is placed in a hot glycol bath which melts out the Tin-Bismuth without affecting the plastic. Finally, the part is washed in water and fitted with whatever brass fittings, rubber seals, etc. are needed. Siemens uses the lost core process to manufacture many of the air intake manifolds. My goal for the summer was to determine if the use of composites in the design of an under hood engine component was possible and practical. The current production materials for the investigated part are cast iron or steel This means the parts are heavy and radiate a significant amount of heat under the hood. A composite part would be lighter in weight and handle heat more efficiently. The following report discusses the physics, procedure, and results of the investigation.