Search Results (4)

The current trend in pure electric heavy-duty commercial vehicles (PEHCVs) is the increasing utilization of automated manual transmission (AMT) to optimize driveline efficiency. However, the existing gear-shift schedule of AMT fails to account for crucial factors such as vehicle load and slope gradient, leading to frequent gear position changes during uphill driving, compromising driving comfort. This study proposes a novel approach incorporating the vehicle’s load and slope gradient to develop an enhanced gear-shift strategy based on fuzzy logic control to address this issue more effectively. Initially, a dynamic gear-shift schedule was formulated for a 6-speed AMT-equipped PEHCV, followed by an analysis of the impact of vehicle load and slope gradient on the gear-shift schedule. Subsequently, an adaptive gear-shift design framework was developed using fuzzy logic control, considering inputs such as acceleration pedal opening, vehicle load, and slope gradient. Simultaneously, the velocity correction factor was designed as an output to adjust the velocity of gear-shift points based on the dynamic gear-shift schedule. Finally, simulations were conducted under various operating scenarios, including different slope gradients, varying vehicle loads, changing pedal openings, and random scenarios to compare and validate the proposed gear-shift schedule against its predecessor—the previous dynamic gear-shift schedule. The results demonstrate that the proposed gear-shift schedule exhibits exceptional adaptability to various driving scenarios. The average acceleration time can be reduced by over 20%, while the gear-shift frequency within 200 s can be decreased by more than 30 times. Full article

With the global energy transition and advancements in electric vehicle technology, the use of pure electric heavy-duty vehicles in logistics is rising. However, current highway grade design standards do not fully consider their performance characteristics, making it urgent to establish appropriate grade limits. This study aims to explore the maximum grade and the critical length suitable for pure electric heavy-duty vehicles on highways. A co-simulation platform for pure electric heavy-duty vehicles was built using TruckSim and MATLAB/Simulink. A comparative analysis was conducted on the climbing characteristics of pure electric heavy-duty vehicles and traditional fuel-powered vehicles. Additionally, the climbing speed decay degree (DV) was introduced to investigate the speed variation characteristics of pure electric heavy-duty vehicles under the joint influence of multiple factors. These findings serve as the basis for determining the maximum grade and the critical length applicable to pure electric heavy-duty vehicles on highways. The research findings indicate that, compared to traditional fuel-powered heavy-duty vehicles, pure electric heavy-duty vehicles exhibit smoother acceleration and deceleration processes, smaller speed fluctuations, higher travel speeds, and greater equilibrium speed values during uphill climbing. The power-to-weight ratio has a greater impact on the climbing speed of pure electric heavy-duty vehicles, while the initial vehicle speed has a relatively minor effect. It was observed that the dynamic performance of pure electric heavy-duty vehicles does not align with the maximum grade stipulated by current regulations in China. These research findings provide important reference points for road longitudinal section design and vehicle management in road freight enterprises. Full article

Because of the rising demand for CO₂ emission limits and the high cost of fuel, the electrification of heavy-duty vehicles has become a hot topic. Manufacturers have tried a variety of designs to entice customers, but the outcomes vary depending on the application and availability of recharging. Without affecting vehicle range, plug-in hybrids provide a potential for the automobile industry to reach its CO₂ reduction objectives. However, the actual CO₂ emission reductions will largely rely on the energy source, user behavior, and vehicle design. This research compares a series plug-in hybrid medium-duty truck against two baselines: nonhybrid and pure electric commercial trucks. As well as evaluating and contrasting the different tools to quantify CO₂ emissions, this manuscript offers fresh information on how to simulate various powertrain components used in electrified vehicles. According to the findings, plug-in hybrids with batteries larger than 50 kWh can reduce emissions by 30%, while still meeting the 2030 well-to-wheel CO₂ regulations. The recommended battery size for plug-in hybrid is 100 kWh, and for electric vehicles it is 320 kWh. The range of a plug-in hybrid is 18% longer than that of nonhybrid, 6% longer than that of a full hybrid, and 76% longer than that of a pure electric powertrain with a fully charged battery. Full article

The exponential growth of electric and hybrid vehicles in the last five years forecasts a waste problem when their batteries achieve end-of-life. Li-ion batteries for vehicles have been assembled using materials from natural resources (as Li, Fe, Al, Cu Co, Mn and P). Among them, LiFePO₄ cathode materials have demonstrated advantages such as charge–discharge cycles, thermal stability, surface area and raw materials availability (against Ni and Co systems). Due to the performance, LFP batteries stand out in heavy duty fleet, achieving 90% of new energy buses in China. To achieve the circular economy, the recycling of LFP batteries may be carried out by pyrometallurgy (thermal processing), hydrometallurgy (aqueous processing) or both in combination. Comparatively, hydrometallurgical processing is more advantageous due to its low energy consumption and CO₂ emissions. In addition, Li may be recovered in a high-pure grade. This work is a literature review of the current alternatives for the recycling of LFP batteries by hydrometallurgy, comparing designed processes in the literature and indicating solutions towards a circular economy. The major recycling steps of hydrometallurgy routes such as pre-treatments, leaching and purification steps will be gathered and discussed in terms of efficiency and environmental impact. Full article