Energy Savings of a Hybrid Truck Using a Ravigneaux Gear Train

The series-parallel powertrains for high-power vehicles have complex architectures. They generally require multiple planetary gear trains with several clutches. The maintenance and durability of the clutches are nonetheless not relevant for on-board implementation. In this paper, a new architecture with a Ravigneaux gear train without clutches is proposed. The complexity of the architecture is then reduced. The objective of this paper is to illustrate the benefits of such a powertrain in terms of energy savings in comparison to a conventional truck. Due to the mechanical constraints of the gear train, the control scheme of the vehicle is complex to design. A functional description, the Energetic-Macroscopic Representation, is then used to organize the control scheme. Simulation results, with a rules-based energy-management strategy, show a reduction of the fuel consumption from 6% to 19% depending on the driving cycles. To prove the use of a Ravigneaux gear train as a power split device, the basic operating modes are validated in the open-loop control on a test bed.