The Effect of Driving Intensity and Incomplete Charging on the Fuel Economy of a Hymotion Prius PHEV

On-road testing was conducted on a Hymotion Prius plug-in hybrid electric vehicle (PHEV) at the Electric Transportation Engineering Corporation in Phoenix, Arizona. The tests were comprised of on-road urban and highway driving during charge-depleting and charge-sustaining operation. Determining real-world effectiveness of PHEVs at reducing petroleum consumption in real world driving was the main focus of the study. Throughout testing, several factors that affect fuel consumption of PHEVs were identified. This report discusses two of these factors: driving intensity (i.e., driving aggressiveness) and battery charging completeness. These two factors are unrelated, yet both significantly impact the vehicle’s fuel economy. Driving intensity was shown to decrease fuel economy by up to half. Charging completeness, which was affected by human factors and ambient temperature conditions, also showed to have great impact on fuel economy for the Hymotion Prius. These tests were performed for the U.S. Department of Energy’s Advanced Vehicle Testing Activity. The Advanced Vehicle Testing Activity, part of the U.S. Department of Energy’s Vehicle Technology Program, is conducted by the Idaho National Laboratory and the Electric Transportation Engineering Corporation.