Using Design of Experiments to Size and Calibrate the Powertrain of Range-Extended Electric Vehicle 2020-01-0849
A Range-Extended Electric Vehicle (REEV) usually has an additional power source which includes a range extender that can provide additional range when the main Rechargeable Energy Storage System (RESS) runs out. The range extender can be a fuel cell, a gas turbine, or an Internal Combustion Engine bolted to a generator. Sizing the powertrain for a REEV is primarily to investigate the relationship between the capacity of the main RESS and the power rating of the range extender. Worldwide harmonized Light vehicles Test Procedures (WLTP) introduced a Utility Factor (UF) which is a curve that calculates the weighted test results for the Off-Vehicle Charging-Hybrid Electric Vehicles (OVH-HEVs) depending upon the measured Charge Depleting mode range result and Charge Sustaining mode Fuel Consumption (FC). Therefore, the RESS capacity, the range extender power rating, the control strategy, and the UF are the key factors affecting the weighted FC of a REEV on the test cycle. The aim of this study is to demonstrate a fast approach to develop REEV powertrain. It can size the capacity of the RESS (assumed battery for this paper) and the power rating of the range extender and meanwhile consider the control strategy and the UF for a REEV, using simulation and Design of Experiments (DoE) tools. For the selected REEV powertrain, a DoE test matrix of the battery capacity, range extender power rating, and control strategy was created. The test matrix was then imported into the simulation environment to perform the driving cycle simulations. After that, the simulation results along with the UF were used to calculate the weighted FC. Finally, a REEV weighted FC emulator model was created and interrogated using model visualisation and optimisation methods. Furthermore, the weighted FC calculated by using different regional Utility Factors was compared and discussed.
Ran Bao, James Baxter, Pascal Revereault