An investigation of hydraulic hybrid transmission based on power split concept

Hydrostatic transmissions are extensively used in heavy duty vehicles due to their high power density characteristics. Hydraulic hybrid transmissions are promising options for energy saving transmission systems in automotive applications. The task of this research is to investigate hydraulic hybrid transmission based on power split principle for energy saving potential by developing, modeling and analyzing hybrid Output Coupled Power Split Drive (OCPSD) configurations and comparative assessment with full series hybrid transmission. The sizing of two OCPSD-Hybrid configurations and a full series hybrid configuration are illustrated for class-6 delivery truck application. Energy recovery system is designed to capture braking energy by using hydraulic accumulators. Models of OCPSD-Hybrid and full series hybrid configurations are developed using PSDD software tool. A comparative assessment of both the concepts for sample local delivery and highway cycle shows a good fuel saving potentials by OCPSD-Hybrid transmission. Also, there is a scope for reducing the fuel consumption by applying optimal engine management. A test set-up with Hardware-in-the-loop (HiL) principle to verify the energy consumption and validation of various advanced control strategies of OCPSD hybrid transmission is proposed. The components of HiL test set-up and operational details are demonstrated