Novel design of compound coupled hydro-mechanical transmission on heavy-duty vehicle for energy recycling

Abstract

How to efficiently transmit power and reuse/recover energy has been the subjects of heated discussion in the high-power transmission field. Regarding heavy-duty vehicles, they used to be equipped with a gearbox as a typical type of high-power transmission to deliver power to the wheel. However, a gearbox transmission has quite complex mechanical structure for realizing a large speed-regulating range, and it has an inevitable drawback of weighing too much. In addition, it cannot reuse/recover energy. In this study, a novel design of a compound coupled hydro-mechanical transmission (CCHMT) is proposed to realize energy reuse/recovery on heavy-duty vehicles. The CCHMT has an optimal structure coupled with hydraulic and mechanical components, which makes its speed change continuously and keep the engine running with a high fuel economy. Moreover, compared with both hybrid and battery electric vehicles, vehicle with CCHMT has higher power density. To validate the transmission's feasibility and operational efficiency, simulation modeling and experiments are conducted. The CCHMT can transform unstable energy under a wide speed-regulation range, reuse/recover a vehicle's excess energy at an efficiency of 82.30%/62.94%, and provide a stable driving torque with a high efficiency of 76%, which shows a good energy management performance on heavy-duty vehicle's hydraulic system.