Vehicle System Design Process for a Series-Parallel Plug-in Hybrid Electric Vehicle 2012-01-1774

The Hybrid Electric Vehicle Team of Virginia Tech is one of 15 schools across the United States and Canada currently competing in EcoCAR 2: Plugging In to the Future. EcoCAR 2 is a three year competition that mimics GM's Vehicle Development Process (VDP): design, build, then refine. The first step in the design process is the selection of a powertrain architecture. In the architecture selection process, HEVT considered three options: a Battery Electric Vehicle (BEV), a Series Plug-in Hybrid Electric Vehicle (PHEV), and a Series-Parallel PHEV. The team chose the Series-Parallel PHEV based on powertrain modeling and simulation and CAD packaging analysis. Next, the team looked at a variety of component combinations and selected the one that offered the best capacity to meet competition and team goals. These components are then packaged in the CAD model to plan for component integration. As this integration was happening, a control system was also being developed. A Hybrid Vehicle Supervisory Controller (HVSC) will be added to the vehicle along with the other hybrid components. This controller handles high level tasks and communicates with production component control modules to effectively, efficiently, and safely control the vehicle. The algorithm implemented on the HVSC simultaneously compares all possible powertrain operating and selects the most efficient mode of operation. In addition to component packaging and control system development, one more task completed during year 1 is the design of the Energy Storage System (ESS). This system houses the High Voltage (HV) battery pack and is responsible for distribution of HV power to electric components in the vehicle. This work includes thermal modeling and analysis of the battery pack and any wiring needed for power as well as structural analysis of the enclosure. Overall, HEVT has nearly completed design of a Series-Parallel PHEV that meets or exceeds all of the EcoCAR 2 competition requirements. Years 2 and 3 will be spent integrating this design into a working prototype.