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51.
在能源危机和环境污染问题的压力下,寻找替代石油的新能源车成了必然的选择。世界各大汽车公司以及国内各大科研机构和高等院校纷纷致力于开发清洁节能汽车,新能源汽车获得了长足发展。在我国发展新能源汽车对整个中国汽车业的发展意义重大。文章介绍了目前世界上5种新能源汽车和国内外新能源汽车的发展现状和前景,指出我国发展新能源汽车所面临的问题,建议政府应大力扶持,加大研发力度;加强行业和国际间合作,使新能源技术发展走向多元化。 相似文献
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The rapid development of China’s high-speed rail (HSR) has caused great concern worldwide, and its various environmental impacts is also a main topic. As such, a comprehensive assessment of these environmental impacts is significant for future HSR construction. In this study, a hybrid input-output life cycle method is applied to evaluate multi-footprints of Beijing-Tianjin intercity HSR, namely, carbon, water, land, and material footprints. Results show that the total carbon, water, land, and material footprints of the entire Beijing-Tianjin HSR construction are 3669.0 kt CO2, 54954.7 kt fresh water, 45830.6 ha land, and 8474.2 kt original materials. In the construction stage, bridge and rail systems have the largest environmental impacts, totally contributing above 74% of the four footprints. The indirect footprints from upstream material production have the dominant effects, accounting over 89% in the four footprints. Metal smelting and rolling, transportation equipment manufacturing, and non-metallic mineral products are high-water-consuming and high-emission sectors in raw material production. Improving industrial production efficiency, optimizing line layout, optimizing production distribution and construction process management are key mitigation ways for multi-footprints. 相似文献
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M. Sofian Basrah Efstathios Siampis Efstathios Velenis Dongpu Cao Stefano Longo 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2017,55(11):1665-1685
Modern hybrid electric vehicles employ electric braking to recuperate energy during deceleration. However, currently anti-lock braking system (ABS) functionality is delivered solely by friction brakes. Hence regenerative braking is typically deactivated at a low deceleration threshold in case high slip develops at the wheels and ABS activation is required. If blending of friction and electric braking can be achieved during ABS events, there would be no need to impose conservative thresholds for deactivation of regenerative braking and the recuperation capacity of the vehicle would increase significantly. In addition, electric actuators are typically significantly faster responding and would deliver better control of wheel slip than friction brakes. In this work we present a control strategy for ABS on a fully electric vehicle with each wheel independently driven by an electric machine and friction brake independently applied at each wheel. In particular we develop linear and nonlinear model predictive control strategies for optimal performance and enforcement of critical control and state constraints. The capability for real-time implementation of these controllers is assessed and their performance is validated in high fidelity simulation. 相似文献
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A new local search method with hybrid neighborhood for Job shop scheduling problem is developed. The proposed hybrid neighborhood is not only efficient in local search, but also can help overcome entrapments while search procedure get trapped at local optima and carry the search to areas of the feasible set with better prospect. New strategies used for breaking out of entrapments are presented and they are helpful for the procedure to improve local optima. A performance comparison of the proposed method with some best-performing algorithms on all 10-job, 10-machine benchmark problems and the other two problems generated by Fisher and Thompson ( ie. , FT6 and FT20) is made. The experiment results show the better optimal performance of the proposed algorithm. 相似文献
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This paper presents a cost-benefit analysis (CBA) of hybrid and electric city buses in fleet operation. The analysis is founded on an energy consumption analysis, which is carried out on the basis of extensive simulations in different bus routes. A conventional diesel city bus is used as a reference for the CBA. Five different full size hybrid and electric city bus configurations were considered in this study; two parallel and two series hybrid buses, and one electric city bus. Overall, the simulation results indicate that plug-in hybrid and electric city buses have the best potential to reduce energy consumption and emissions. The capital and energy storage system costs of city buses are the most critical factors for improving the cost-efficiency of these alternative city bus configurations. Furthermore, the operation schedule and route planning are important to take into account when selecting hybrid and electric city buses for fleet operation. 相似文献
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Due to frequent stop-and-go operation and long idling periods when driving in congested urban areas, the electrification of commercial delivery trucks has become an interesting topic nationwide. In this study, environmental impacts of various alternative delivery trucks including battery electric, diesel, diesel-electric hybrid, and compressed natural gas trucks are analyzed. A novel life cycle assessment method, an environmentally-extended multi-region input-output analysis, is utilized to calculate energy and carbon footprints throughout the supply chain of alternative delivery trucks. The uncertainties due to fuel consumption or other key parameter variations in real life, data ranges are taken into consideration using a Monte Carlo simulation. Furthermore, variations in regional electricity mix greenhouse gas emission are also considered to present a region-specific assessment for each vehicle type. According to the analysis results, although the battery electric delivery trucks have zero tailpipe emission, electric trucks are not expected to have lower environmental impacts compared to other alternatives. On average, the electric trucks have slightly more greenhouse emissions and energy consumption than those of other trucks. The regional analysis also indicates that the percentage of cleaner power sources in the electricity mix plays an important role in the life cycle greenhouse gas emission impacts of electric trucks. 相似文献
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《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2012,50(10):1489-1501
Fault detection is considered to be one way to improve system reliability and dependability for railway vehicles. The secondary lateral and anti-yaw dampers are the most critical parts in railway suspension systems. So far, the dampers have been modelled as linear components in the fault detection and isolation observer design. In this work, a Hybrid Extended Kalman filter is used to capture the nonlinear characteristics of the dampers. In order to detect and isolate faults, a nonlinear residual generator is developed, which can distinguish clearly between different types of faults. A lateral half train model serves as an example for the proposed technique. The results show that failures in the nonlinear suspension system can be detected and isolated accurately. 相似文献
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