EcoCAR 3 is a four year hybrid vehicle competition sponsored by General Motors, Argonne National Laboratories, and the Department of Energy. The goal of the competition is to convert a stock 2016 Chevrolet Camaro into a hybrid in order to reduce its environmental impact while maintaining its performance. I joined Georgia Tech's EcoCAR team in the fall of 2015 and have focused on the design, analysis, fabrication, and integration of several components of our custom drivetrain.
The overall layout of the vehicle is a RWD P3 Parallel Plug-in Hybrid Electric Vehicle. That means that the car uses an electric motor in parallel with the internal combustion engine (ICE) to drive the rear wheels. In order to accomplish this, the electric motor is connected to the driveshaft using a transfer case. This allows the ICE and electric motor to either power the wheels individually or together in hybrid mode.
The electric motor (~100 lbs) and transfer case (~65 lbs) were to be securely mounted to the vehicle and capable of withstanding 20g loads in several crash scenarios. I designed all of the mounts, analyzed them using FEA in Siemens NX, and did the majority of the fabrication. In fabricating these mounts I used the following machinery: CNC Mill, Waterjet, and Miter Saw. All mounts were made from a mix of high strength steel and aluminum based on the mount's function and expected forces.
The transfer case and electric motor needed to be coupled in order to transfer power from the motor to the driveshaft. The components' connectors were not compatible and an adapter needed to be designed.
The addition of the transfer case to the driveline required a custom driveshaft. The team had initially modified the stock Camaro driveshaft. That design led to significant vibrations and I was tasked with redesigning the driveshaft.
The final design utilized the driveshaft from a Cadillac CTS and only required minor modifications to work in our vehicle. The CTS driveshaft had connections for both the transmission and the transfer case as well as 2 CV joints. The only modification necessary was to shorten the driveshaft and create a mounting point for the center bearing. The previous design was plagued by additional components to connect to the transmission and transfer case and the misalignment of U-Joints. Eliminating the need for these additional components greatly increased the vehicle's ride quality. Above: The adjustable mounting of the center bearing which was CNC milled to self locate inside of the transmission tunnel.