The first priority for General Motors engineers working on the Chevy Volt has been to develop a powertrain that makes economic and environmental sense. As my colleague Chuck Murray has been blogging, there has been some controversy over GM’s interesting approach.
The second priority will be to dramatically reduce the vehicle’s weight in second- and third-generation vehicles. The Volt is built on the Chevy Cruze platform and weighs almost 3,800 pounds. The Cruze weighs 2,832 pounds. The reason: the battery package alone weighs 435 pounds, and there is other new gear associated with the Volt’s new powertrain.
Use of aluminum in the engine block to replace iron would be a logical place to start. The lost foam casting process would allow more complex and detailed features to be cast directly into the engine block. A near net shape part would reduce weight even beyond the difference in the weight of the materials. The foam pattern is formed from expandable beads, usually pentane-blown polystyrene. GM now has more than five years’ experience with the lost foam process on engine blocks used in trucks and sports utility vehicles.
The Volt would also be an ideal place to use the composite underbody that GM has been developing as part of the USCAR project. USCAR has reported significant improvements in the manufacturability and quality of fabric-reinforced sections that would replace stamped steel assemblies.