Current Issue : April-June Volume : 2024 Issue Number : 2 Articles : 5 Articles
Faced with the charging difficulties of free-floating shared electric vehicles and the high cost of single-demand mobile charging, this paper proposes a cooperative charging planning method based on the complementary advantages of fixed charging stations and mobile charging vehicles, which can charge shared electric vehicles more efficiently and reduce the charging cost at the same time. A bi-level programming model for fixed and mobile cooperative charging is constructed. The upper level of the model is the system charging total cost minimization model, which searches for the optimal charging scheme and number of mobile charging vehicles. The lower level model is a fixed and mobile cooperative charging path planning model, which calculates the optimal routes for the mobile charging vehicles and the shared electric vehicles that need to be transferred to the fixed charging station. The example results show that the cost of the proposed fixed-mobile cooperative charging scheme is reduced by 12.6% when compared to the fixed-only charging scheme, and by 14.9% when compared to the mobile-only charging scheme....
Solar energy is recognized as an alternative to combustion engines to reduce the environmental impact and increase the endurance of unmanned aerial vehicles (UAVs). This work aims to present a project for a solar UAV to contribute to the mission of the Air Force Academy Research Center and test the energy system on the ground. To achieve this study’s objectives, a literature review on photovoltaic cells (PVCs), batteries, and maximum power point tracking algorithms was conducted. The most appropriate airframe and wing designs for this particular type of flight are then investigated. Following that, the project requirements and mission profile were defined, and the copper indium gallium selenide eFilm cells, a solar power management system (SPMS), avionics, and payload required for the mission were chosen based on them. A methodology for ground testing of solar systems was created and used, achieving an endurance of 7 h and 34 min on an April day. The SPMS achieved an efficiency of around 96%, while PVCs ranged from 11.3 to 14.1%....
Climate change and air pollution are two significant challenges facing our society and represent a major driver for new developments in the transport sector. As a consequence, automotive manufacturers have focused on the electrification of vehicle propulsion systems and offer a wide range of hybrid and full-electric vehicles in different classes. However, in the world’s most densely populated metropolitan areas, small and lightweight vehicles are key for the mobility of millions. Traditionally these vehicles have provided cost-effective transportation which is difficult to preserve with vehicle electrification. Many of these light vehicles, such as scooters and all-terrain vehicles, use internal combustion engines in combination with a continuously variable rubber belt transmission which provides a simple, comfortable and cost-effective transmission technology but with poor efficiency and high maintenance costs. In this contribution, a novel full hybrid powertrain concept is proposed that offers a similar driving experience to conventional continuously variable transmissions while providing significantly improved performance and fuel economy combined with low system complexity. In its basic configuration, the hybrid powertrain can operate without active actuators and even with mechanical throttle control of the internal combustion engine. This minimalist approach reduces system costs and helps to create a competitive solution for price-sensitive markets. The hybrid system is based on a planetary gear set that combines the internal combustion engine and an electric motor. It is complemented by a centrifugal clutch and one-way clutch, resulting in different operating modes for low and high speeds as well as for electric driving. This paper describes the mechanical design and control approach of the proposed hybrid powertrain layout. In order to evaluate the basic functionalities, a prototype vehicle was built and tested. This contribution shows the integration of the hybrid powertrain concept in a prototype vehicle and proves the fulfilment of all required full hybrid functionalities....
This article investigates the impact of loading on the hybrid powertrain of the FCAT- 30 model, equipped with a proton-exchange-membrane fuel cell (PEMFC) and a nickel–metal hydride (NiMH) battery. This study involves analyzing structural component performance based on voltage and current measurements of the fuel cell, battery, and powertrain. Tests conducted under different load conditions reveal significant differences in battery current and fuel-cell voltage, highlighting the crucial role of the battery in the powertrain. External loading induces cyclic operation of the fuel cell, generating peak power. The energy balance analysis demonstrates that, under no-load conditions, the vehicle consumes 37.3% of its energy from the fuel cell, with a total energy consumption of 3597 J. Under load, the energy from the battery is significantly utilized, resulting in a constant fuel-cell share of approximately 19%, regardless of the vehicle’s load. This study concludes that the battery predominantly drives the powertrain, with the fuel cell acting as a secondary energy source. These findings provide valuable insights into the power distribution and energy balance in the hybrid powertrain. Using a load driving profile reduced the fuel-cell-stack energy contribution by 6.85% relative to driving without an external load....
Due to the rapid increase in the use of electric vehicles and instability in energy supply, the application of vehicle-to-grid (V2G) technology has gained attention in the freight transportation sector. V2G has the potential to increase the efficiency of power grid and make additional profits by utilizing surplus power from electric vehicle batteries. This paper proposes an optimization model for electric trucks (ETs) to provide operational decision-making support for the freight transportation sector. The objective of the model is to minimize the total net cost, which includes charging cost, discharging reward, and time penalties, while considering changes in ET charging cost and the system marginal price. Furthermore, we conduct sensitivity analysis in the vehicle routing problem with soft time windows using ETs in the V2G system....
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