Current Issue : October - December Volume : 2018 Issue Number : 4 Articles : 5 Articles
As the market for electric vehicles grows at a remarkable rate, various models of electric\nvehicles are currently in development, in parallel to the commercialization of components for diverse\ntypes of power supply. Cabin heating and heat management components are essential to electric\nvehicles. Any design for such components must consider the requirements for heating capacity\nand power density, which need to reflect both the power source and weight reduction demand\nof any electric vehicle. In particular, design developments in electric heaters have predominantly\nfocused on experimental values because of structural characteristics of the heater and the variability\nof heat sources, requiring considerable cost and duration. To meet the ever-changing demands of the\nmarket, an improved design process for more efficient models is essential. To improve the efficacy\nof the design process for electric heaters, this study conducted a Computational Fluid Dynamics\n(CFD) analysis of an electric heater with specific dimensions by changing design parameters and\noperating conditions of key components. The CFD analysis modeled heat characteristics through the\napplication of user-defined functions (UDFs) to reflect temperature properties of Positive Temperature\nCoefficient (PTC) elements, which heat an electric heater. Three analysis models, which included\nfin as well as PTC elements and applied different spaces between the heat rods, were compared\nin terms of heating performance. In addition, the heat performance and heat output density of\neach analysis model was analyzed according to the variation of air flow at the inlet of the radiation\nsection of an electric heater. Model B was selected, and a prototype was fabricated based on the\nmodel. The performance of the prototype was evaluated, and the correlation between the analysis\nresults and the experimental ones was identified. The error rate between performance change\nrates was approximately 4%, which indicated that the reliability between the design model and the\nprototype was attained. Consequently, the design range of effective performance and the guideline for\nlightweight design could be presented based on the simulation of electric heaters for various electric\nvehicles. The fabrication of prototypes and minimum comparison demonstrated opportunities to\nreduce both development cost and duration....
To meet the requirements of strict fuel consumption and emission limits, continuously increasing the thermal efficiency of\nan internal combustion engine and decreasing its exhaust emissions are the main challenges to its sustainable development\nwithin the automotive industry. Considering the competition with other zero-emission powertrain systems, such as vehicle\nbatteries and fuel cells, the development of the internal combustion engine needs to focus on producing higher efficiency and\nzero emissions to meet the request of CO2 reduction. This paper introduces two novel concepts for an internal combustion\nengine featuring high efficiency and zero emissions. Referred to as the argon power cycle engine fueled with either hydrogen\nor natural gas within an oxygenââ?¬â??argon mixture, its fundamentals and characteristics are expounded. This includes a method\nnecessary to absorb carbon dioxide when natural gas is used as fuel instead of hydrogen....
The feasibility of monitoring the dipped rail\njoint defects has been theoretically investigated by simulating\na locomotive-mounted acceleration system negotiating\nseveral types of dipped rail defects. Initially, a\ncomprehensive locomotive-track model was developed\nusing the multi-body dynamics approach. In this model, the\nlocomotive car-body, bogie frames, wheelsets and driving\nmotors are considered as rigid bodies; track modelling was\nalso taken into account. A quantitative relationship\nbetween the characteristics (peakââ?¬â??peak values) of the axle\nbox accelerations and the rail defects was determined\nthrough simulations. Therefore, the proposed approach,\nwhich combines defect analysis and comparisons with\ntheoretical results, will enhance the ability for long-term\nmonitoring and assessment of track systems and provides\nmore informed preventative track maintenance strategies....
Plug-in electric vehicles are the currently favoured option to decarbonize the passenger\ncar sector. However, a decarbonisation is only possible with electricity from renewable energies and\nplug-in electric vehicles might cause peak loads if they started to charge at the same time. Both of\nthese issues could be solved with coordinated load shifting (demand response). Previous studies\nanalysed this research question by focusing on private vehicles with domestic and work charging\ninfrastructure. This study additionally includes the important early adopter group of commercial fleet\nvehicles and reflects the impact of domestic, commercial, work, and public charging. For this purpose,\ntwo models are combined that capture the market diffusion of electric vehicles and their charging\nbehaviour (ALADIN), as well as the load shifting potential of several new energy technologies\n(eLOAD). In a comparison of three different scenarios, we find that the charging of commercial\nvehicles does not inflict evening load peaks in the same magnitude as purely domestic charging of\nprivate cars does. Also, for private cars, charging at work occurs during the day and may reduce the\nnecessity of load shifting while public charging plays a less important role in total charging demand\nas well as load shifting potential. Nonetheless, demand response reduces the system load by about\n2.2 GW or 2.8% when domestic and work charging are considered when compared to a scenario with\nonly domestic charging where a new peak might be created in the winter hours due to load shifting\ninto the night....
This work presents a detailed breakdown of the energy conversion chains from intermittent\nelectricity to a vehicle, considering battery electric vehicles (BEVs) and fuel cell electric vehicles\n(FCEVs). The traditional well-to-wheel analysis is adapted to a grid to mobility approach by\nintroducing the intermediate steps of useful electricity, energy carrier and on-board storage.\nSpecific attention is given to an effective coupling with renewable electricity sources and associated\nstorage needs. Actual market data show that, compared to FCEVs, BEVs and their infrastructure\nare twice as efficient in the conversion of renewable electricity to a mobility service. A much larger\ndifference between BEVs and FCEVs is usually reported in the literature. Focusing on recharging\nevents, this work additionally shows that the infrastructure efficiencies of both electric vehicle (EV)\ntypes are very close, with 57% from grid to on-board storage for hydrogen refilling stations and 66%\nfor fast chargers coupled with battery storage. The transfer from the energy carrier at the station\nto on-board storage in the vehicle accounts for 9% and 12% of the total energy losses of these two\nmodes, respectively. Slow charging modes can achieve a charging infrastructure efficiency of 78%\nwith residential energy storage systems coupled with AC chargers....
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