SR Technology Innovations (SRTI) has been working with CNH Industrial in Basildon on the build of the ElecTra hybrid tractor transmission.
The project, developed over the last three years, has brought together CNH Industrial, Advanced Electric Machines (AEM), the University of Bath, and SRTI. The project was part-funded by Innovate UK, whose support was invaluable, particularly during the challenges of the COVID pandemic.
Tractors are already highly complex machines, and hybridisation is particularly challenging, requiring the integration of many additional components. The new transmission is controlled by SRTI’s Vehicle Control Unit (VCU), developed as part of the ElecTra project. The VCU interfaces with the tractor’s existing systems via multiple CANbus networks and directly manages the inverters, motors, multi-gear transmission, and supporting systems in the hybrid powertrain.
The VCU software, also developed by SRTI, uses libraries built in MATLAB and Simulink, enabling auto-coding of control algorithms. This model-based design approach has made it easier for engineers from different disciplines to collaborate and has helped speed up the development of control software for the transmission.
With the system now built and integrated, initial functional testing is about to get underway. This will be followed early in the new year by powertrain testing at the IAAPS facility near Bristol, where the hybrid transmission’s performance will be evaluated in one of their new powertrain test cells.