Simulation-Based Comparative Assessment of a Multi-Speed Transmission for an E-Retrofitted Heavy-Duty Truck

Abstract

Electric retrofitting (e-retrofitting) is a viable option for accelerating the renewal of heavy-duty vehicle fleets to reduce the related emissions. We introduce a simulation-based assessment of e-retrofitting strategies for heavy-duty vehicles. Our simulation tool, an electric vehicle fleet simulation toolbox, comprises three modules, namely driving cycles, vehicle dynamics, and vehicle profiles. The first allows for the creation of realistic driving cycles based on GPS data from real routes. The vehicle dynamics and vehicle profiles incorporate, e.g., the modelling of the powertrain and driving conditions. Ten realistic driving cycles were created and used for investigating and comparing three different powertrain alternatives, including the original diesel powertrain, electric with a single-speed transmission and electric with a multi-speed transmission. The vehicles were simulated in two different heavy-load scenarios. First, driving with a cargo load represented by the maximum vehicle weight and second, driving with snow ploughing. We found that the multi-speed transmission in an electric heavy-duty truck significantly improved its traction performance and gradeability. On the other hand, the effect on the electric powertrain efficiency, and thereby on the energy consumption, remained rather minor. Considering the given workload scenarios, our results advocate employing rather than omitting the gearbox in the e-retrofit truck process.

A Review of Big Data in Road Freight Transport Modeling–Gaps and Potentials

“…The digital twin approach replicating a real road transport network operation through data and simulation also opens a new perspective toward fleets' decarbonization planning and forecasting costs. Such an approach can alleviate the risks of costly mistakes in planning and initial piloting during a fleet transitioning phase and further operational optimization and infrastructure planning (Vehviläinen et al 2022). VTT Smart eFleet toolbox recreates the transport network by utilizing validated vehicle models and reconstruction of the road infrastructure.…”

Development of Shift Map for Electric Commercial Vehicle and Comparison Verification of Pneumatic 4-Speed AMT and 4-Speed Transmission with Synchronizer in Simulation

“…However, the unique characteristics of commercial vehicles, which require high torque at low speeds, pose challenges when using a combination of a motor and a single-speed reducer [12,13]. Increasing the reduction ratio for high torque results in reduced efficiency and torque at high speeds, while increasing the size of the motor to enhance torque leads to decreased efficiency and the disadvantages of increased weight and cost [14,15]. For these reasons, research on multi-speed transmissions for commercial electric vehicles, including optimization of gear ratios, modeling, validation of transmission and simulation, is also underway [16][17][18].…”