Development and Application of Enhanced Compacted Graphite Iron for the Bedplate of the New Chrysler 4.7 Liter V-8 Engine

For the new 4.7 L, V-8 engine, which was introduced in the all new 1999 Jeep Grand Cherokee, Chrysler product engineers found they needed a bedplate material that was significantly stronger and stiffer than gray iron to help meet engine weight requirements. The material also had to provide good NVH characteristics, be cost effective, and machinable. Intermet Corporation, the casting supplier, wanted a material that was significantly tougher than gray iron, would cast sound in complex sections, and which could be reliably produced on a cost effective basis. This paper presents an overview of the development, properties, casting practices, and engine validation of enhanced compacted graphite iron, a material specifically developed and tailored for the bedplate of the new 4.7 liter engine.