Drive Cycle Fuel Consumption Variability of Plug-In Hybrid Electric Vehicles Due to Aggressive Driving 2009-01-1335

Previous studies and on-road driving by consumers have shown that Hybrid Electric Vehicle fuel economy is very dependent on driver demand in both vehicle speed and vehicle acceleration [1]. The emerging technology of Plug-In Hybrid Vehicles (PHEV) may prove to also be more sensitivity to aggressive driver demand as compared to conventional internal combustion engine vehicles. This is due to the exceptional ability of the PHEV to minimize fuel consumption at mid to low power levels by the significant use of electric propulsion which enables engine downsizing. As vehicle speed and acceleration increase so does the power demand on the powertrain. The fuel consumption is directly affected by this increase in power demand level.

To examine the fuel consumption impact of changing driver characteristics on PHEV’s, testing is conducted on two vehicles (parallel PHEV and power-split PHEV) on a four wheel chassis dynamometer at Argonne’s Advanced Powertrain Research Facility. Testing is conducted in charge depletion and charge sustaining operation on several drive cycles including the UDDS with cycle scaling of x1.0, x1.1, x1.2, x1.3, x1.4. The drive trace vehicle speed is multiplied by the scaling factor whereas the drive trace time is divided by the scaling factor resulting in equal driving distance for all the cycles but the acceleration and speed are increased. Fuel consumption, electrical consumption, and several vehicle parameters are analyzed to investigate the impact changing driver characteristics on the operation of Plug-In Hybrid Electric Vehicles.