Weight Reduction through the Design and Manufacturing of Composite Half-Shafts for the EcoCAR 3

EcoCAR 3 is a university based competition with the goal of hybridizing a 2016 Chevrolet Camaro to increase fuel economy, decrease environmental impact, and maintain user acceptability. To achieve this goal, university teams across North America must design, test, and implement automotive systems. The Colorado State University (CSU) team has designed a parallel pretransmission plug in hybrid electric design. This design will add torque from the engine and motor onto a single shaft to drive the vehicle. Since both the torque generating devices are pre-transmission the torque will be multiplied by both the transmission and final drive. To handle the large amount of torque generated by the entire powertrain system the vehicle's rear half-shafts require a more robust design. Taking advantage of this, the CSU team has decided to pursue the use of composites to increase the shaft's robustness while decreasing component weight. The project is meant to explore composites manufacturing techniques and their use in the automotive industry. This paper will discuss the design and manufacturing of a composite half-shaft and the integration of a constant velocity joint (CVJ) for application in a hybrid electric Chevrolet Camaro. It will focus on the design process, particularly on design for composites manufacturing and the CVJ-shaft interface, where metal, carbon fiber composites, and lubricant will meet. The paper will detail the design for composites manufacturing to reduce manufacturing time and cost as well as validate the design through analysis techniques. Finally it will discuss the feasibility of implementing carbon fiber half shafts in high performance consumer vehicles, such as the Chevrolet Camaro.