Lightweight Piston Design for Increased Reliability and Productivity Requirements

This paper describes the process through which a new approach has been developed for the design and manufacture of cast aluminum pistons, termed the mono-core piston. The result is a piston with improved quality, reliability, durability, and productivity, while maintaining or improving all functional requirements. This result comes from the careful analysis of the design requirements and potential failure modes, value-added analysis of the production process, and careful attention to the process failure mode effects analysis. Design data is presented comparing the traditional, five-piece core design technique to the mono-core design of a production validated piston. The example presented is for an 82mm diameter piston intended for use in a single cylinder, two, three, or four cylinder, 4-stroke engine application. The design is applicable to either air or water cooled engines, single or multi-cylinder configurations, 2- or 4-stroke engines with bores as small as 58mm diameter. It is a lower mass alternative to more conventional gravity-cast pistons and becomes even more advantageous in high piston speed engines.