The Hybrid Electric Vehicle Team of Virginia Tech (HEVT) is participating in the 2009 - 2011 EcoCAR: The NeXt Challenge Advanced Vehicle Technology Competition series organized by Argonne National Lab (ANL), and sponsored by General Motors Corporation (GM), and the U.S. Department of Energy (DOE). Following GM's Vehicle Development Process (VDP), HEVT established team goals that meet or exceed the competition requirements for EcoCAR in the design of a plug-in extended range hybrid electric vehicle. The competition requires participating teams to re-engineer a stock crossover utility vehicle donated by GM. The result of this design process is an Extended Range Electric Vehicle (EREV) that uses grid electric energy and E85 fuel for propulsion. The vehicle design has achieved an SAE J1711 utility factor corrected fuel consumption of 2.9 L(ge)/100 km (82 mpgge) with an all-electric range of 87 km (54 miles) [1]. Using E85 fuel (corn-based in North America for the 2015 timeframe), the well-to-wheels petroleum energy use and greenhouse gas emissions are reduced by 91% and 18% respectively when compared to the stock 4-cylinder gasoline-fueled vehicle.
In year 2 of EcoCAR, HEVT focused on the integration of components, while year 3 was focused on refinements. The integration and refinements of years 2 and 3 were focused on meeting the Vehicle Technical Specifications (VTS) established at the beginning of the design process in year 1. This paper will detail the refinements made to the VTREX, explain why the changes were made, and describe the improvements or tradeoffs that had to be made for the vehicle to run reliably. Vehicle test data will be presented from year 2 competition, year 3 competition, dynamometer testing and on-road testing around the Virginia Tech campus. These test results will illustrate how the changes in powertrain components, mechanical integration and controls logic helped the vehicle to meet its target specifications. The test results will also show how accurately the simulations and models that were used to form the VTS matched real world performance.