A growing dependence on foreign oil, along with a heightened concern over the environmental impact of personal transportation, had led the U. S. government to investigate and sponsor research into advanced transportation concepts. One of these future technologies is the hybrid electric vehicle (HEV), typically featuring both an internal combustion engine and an electric motor, with the goal of producing fewer emissions while obtaining superior fuel economy.
While vehicles such as the Virginia Tech designed and built HEV Lumina have provided a substantial proof of concept for hybrids, there still remains a great deal of research to be done regarding optimization of hybrid vehicle design. This optimization process has been made easier through the use of ADVISOR, a MATLAB simulation program developed by the U. S. Department of Energy's National Renewable Energy Lab. ADVISOR allows one to evaluate different drivetrain and subsystem configurations for both fuel economy and emissions levels.
However, the present version of ADVISOR uses a constant power model for the auxiliary power unit (APU) that, while effective for cursory simulation efforts, does not provide for a truly accurate simulation. This thesis describes modifications made to the ADVISOR code to allow for the use of a load sharing APU scheme based on models developed from vehicle testing. Results for typical driving cycles are presented, demonstrating that the performance predicted by the load sharing simulation more closely follows the results obtained from actual vehicle testing. This new APU model also allows for easy adaptation for future APU technologies, such as fuel cells. Finally, an example is given to illustrate how the ADVISOR code can be used for optimizing vehicle design.
This work was sponsored by the U.S. Department of Energy under contract XCG-6-16668-01 for the National Renewable Energy Laboratory.
