<p>Hydrostatic and hydro-mechanical transmissions (HST and HMT respectively), typical in agricultural and off-road equipment, benefit from offering continuously variable vehicle ground speeds. These transmission architectures, however, may suffer from low efficiencies at low speeds and limited speed ranges. Electric variable transmissions (EVTs), in contrast, offer complementary strengths via higher efficiencies at low forward and reverse speeds, full torque from zero to full power, and increased control capabilities. While HST, HMT, and EVT powertrain architectures are not novel, the authors are not aware of work integrating these technologies into hydro-electro-mechanical (HEM) transmission architectures. Thus, this research aimed to develop a physical modeling methodology to explore different power-split transmission technologies using hydraulic, electrical, and mechanical pathways to understand how the complementary nature of the technologies could be used for overall power transmission performance. Modeling was performed using the Modelica® (Modelica Association) modeling language in the Dymola (Dassault Systems®) integrated development environment. Efficiency and power flow vs. torque and speed operating ranges are presented for HST, HMT, EVT, and HEM input- and output-coupled architectures that include regenerative energy considerations. Furthermore, modeling approaches taken, including roadblocks and resolutions, are included. This research extends the&nbsp;state-of-the-art of off-road powertrain technologies by offering the&nbsp;literature an exemplar modeling of HEM-CVT coupling techniques, system integration, and power flow architectures in Modelica®&nbsp;modeling language.</p>

Modeling Hybrid Hydro-Electro-Mechanical Power-Split Propulsion Systems

Paper Proceedings: https://asmedigitalcollection.asme.org/FPST/FPMC2021/volume/85239

2021 ASME/BATH Symposium on Fluid Power and Motion Control (FPMC2021)

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