Fuel Efficiency Analysis and Control of a Series Electric Hybrid Compact Wheel Loader

The escalating demand for more efficient and sustainable working machines has pushed manufacturers toward adopting electric hybrid technology. Electric powertrains promise significant fuel savings, which are highly dependent on the nature of the duty cycle of the machine. In this study, experimental data measured from a wheel loader in a short-loading Y-cycle is used to exercise a developed mathematical model of a series electric hybrid wheel loader. The efficiency and energy consumption of the studied architecture are analyzed and compared to the consumption of the measured conventional machine that uses a diesel engine and a hydrostatic transmission. The results show at least 30% reduction in fuel consumption by using the proposed series electric hybrid powertrain, the diesel engine rotational speed is steady, and the transient loads are mitigated by the electric powertrain. The model also shows that 20% of drive energy could be regenerated through braking using the drive electric motors. Opportunities for engine downsizing are established and the losses are analyzed and compared for both machines. The results show 42% savings in the overall system losses especially the diesel engine and drivetrain.