Cyber-Physical Testing System for Automotive Hybrid Powertrains Featuring Component-in-the-Loop Architecture With Virtual Transmission

The article presents a concept and a verification study of a Component-in-the-Loop (CiL) system intended for laboratory testing of automotive hybrid powertrains. The proposed approach employs a modular system architecture featuring unified interactions between the physical and the virtual domains, and between the software models. The virtual part of the CiL system is based on a model of the transmission whose type is defined by the topology of the studied powertrain. The virtual transmission is interfaced with dynamometers to interact with the physical powertrain components by coordinating their loading regimes in accordance with the simulated operating modes of the powertrain and the vehicle. These principles allow designing scalable CiL architectures for powertrains with multiple driving units. The validity of the concept was evaluated through numerical experiments using a mathematical model of a CiL setup that embodies the Toyota Hybrid System powertrain, which has a power-split continuously variable transmission as its core element. The simulation results confirm that the CiL system correctly replicates operation of the hybrid powertrain in specified driving conditions, while functioning of its control loops remains stable and properly coordinates loading regimes of the driving units.