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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.

General Motors Powertrain Division has developed a new V-8 engine for Cadillac vehicles in the 1990s. The Northstar engine incorporates the use of aluminum for both the cylinder block and head and other lightweight materials throughout. The valve train incorporates direct acting hydraulic lifters actuating the four valves per cylinder through dual overhead camshafts. The primary focus of the project has been to produce an engine of unquestioned reliability and exceptional value which is pleasing to the customer throughout the range of loads and speeds. The engine was designed with a light weight valve train, low valve overlap and moderate lift, resulting in a very pleasing combination of smooth idle and a broad range of power. The use of analytical methods early in the design stage enabled systems to be engineered to optimize reliability, pleaseability and value by reducing frictional losses, noise, and potential leak paths, while increasing efficiency and ease of manufacture.