The development of the fuel saving control strategy for 48 V P0 system: Design and experimental investigation

This paper presents a fuel consumption reduction control strategy for a newly-developed 48 V P0 mild hybrid electric vehicle and evaluates its fuel economy benefit experimentally. The strategy is designed with rule-based methods and utilizes various functions such as start-stop, torque boost, regeneration, load shift, BSG neutral mode and torque interventions with BSG. Fuel consumption comparison tests are performed in the WLTP cycle between the MHEV and the conventional vehicle. The authors evaluate the performance of specific key functions, analyze the energy flow of the 48 V battery, and calculate the fuel saving rate of the MHEV. The SOC of the 48 V battery is balanced in the WLTP cycle. The total energy charged to the 48 V battery is 378 Wh, of which 82% comes from the regeneration pattern. The total energy discharged from the 48 V battery is 355 Wh, of which 85% is consumed by the load shift pattern (BSG neutral state and Discharging state). The fuel consumption of the MHEV is reduced by 7.9% compared with the conventional vehicle in the WLTP cycle. The start-stop, BSG neutral, and torque interventions with BSG save fuel by 3.8%, 0.9%, and 0.5% respectively. The other hybrid functions save fuel by 2.7%.