液化天然气商用车与柴油商用车生命周期能耗差异评价

从生命周期视角,研究了液化天然气（liquefied natural gas,LNG）商用车与柴油商用车在材料制备、零部件加工制造、整车装配、使用、回收利用等整个生命周期各阶段的能源消耗差异,建立了LNG商用车与柴油商用车能耗差异评价模型,并利用该模型对某LNG搅拌车和柴油搅拌车的直接能耗差异和生命周期总能耗差异进行了实证研究。结果表明,LNG搅拌车具有节能优势。     

浅析LNG重型商用车的市场前景

在简要介绍了液化天然气(LNG)重型商用车相关知识的基础上,对我国液化天然气行业情况和目前国内外开发、使用情况进行了阐述,通过对其社会、经济效益的分析,总结了该类车型在节能环保、安全经济等方面的突出优势,预测必将有更为广阔的发展前景和市场需求.同时,对加快发展LNG重型商用车提出建议.     

重型商用车筒式减振器能量回收潜力研究

为了验证重型商用车减振器具有较高的能量回收潜力,对商用车筒式减振器进行了动力学建模与实车路试。通过建立汽车悬架的车身-车轮双质量模型,分析了悬架的动速度、动位移和能量回收效率,并通过实车路试验证了仿真模型的正确性。同时,分析了刚度比、阻尼比、质量比等整车参数对能量回收效率以及动力学性能的影响。结果显示重型商用车具有较高的能量回收潜力,最高瞬时能量值达到1310.6W。这为重型商用车设计液电式馈能悬架提供了参考意义。     

我国重型商用车燃料消耗量Ⅲ阶段法规浅析

在全球汽车油耗标准持续加严的背景下,我国重型商用车油耗标准也逐步加严,以接近国际先进水平。为了提前准备应对重型商用车第Ⅲ阶段油耗国标要求,对标准进行了分析,包括评价方法以及限值加严情况,并简述了重型商用车第Ⅲ阶段油耗限值标准的达标策略。     

重型商用车选换档性能影响因素探讨

重型商用车选换档操纵的舒适性是人们对整车质量的评价标准之一,详细分析了变速器、软轴和操纵器中与选换档性能有关的内部结构及设计参数对重型商用车选换档性能的影响,可为开发新车型和改进车型等提升操纵性能提供依据和方向。     

重型柴油车新排放标准7月1日实施

正2013年5月22日,CCTV新闻频道的朝闻天下栏目播报新闻,称"重型柴油车新排放标准7月1日实施",也就是说重型柴油车国四排放标准7月1日正式实施。重型柴油车包括使用柴油的大型载客汽车和重型载货汽车,排放标准升级以后,重型柴油车可减少5%～7%的油耗,     

重型商用车柴油机欧Ⅵ技术研讨会在杭州举行

为贯彻落实国家节能减排战略,尽快提升我国内燃机排放控制技术水平,更好地规划重型商用车柴油机欧Ⅵ技术路线,引导行业技术发展,履行社会责任,     

重型商用车后悬抗侧倾能力的设计计算

重型商用车由于其结构特点决定了其整车质心位置较高,这就要求其有足够的侧倾角刚度来满足车辆在转弯时的安全性要求。本文根据出口俄罗斯产品认证过程中发现的问题,分析原因,制定优化措施,根据改进后车辆后悬的结构参数,分别计算出钢板弹簧及横向稳定杆的侧倾角刚度,并分析出整车侧倾能力是否满足法规中对搅拌车的性能要求。     

C-WTVC循环下冷热机启动的重型商用车冷却液损失研究

基于AVL实验台架,对一台符合国Ⅵ排放标准的商用重型车开展冷热机启动条件下的瞬态能量流测试,研究该车用发动机在C-WTVC（中国重型商用车瞬态循环）循环工况下冷却液损失变化规律及其对应的影响因素。研究结果表明：冷启动状态下发动机冷却系统调节能力滞后,导致产生更大的冷却液损失;城市循环工况中连续的加减速会造成不必要的冷却液损失;在实际道路循环中,相对于进水温度,出水温度对冷却液损失的影响权重更大;高速循环工况下,冷却液损失占比波动幅度小且在后期稳定在20%附近。以上规律可对重型商用车在瞬态工况下有效降低冷却液损失提供依据。     

重型商用车发动机冷却系统的设计

重型商用车发动机冷却系统的运行性能,对车辆的整体性能及其运转可靠性、车辆使用寿命等,都有着十分重要的作用和影响。本文将结合重型商用车发动机的冷却系统特点,对其设计进行研究,以供参考。     

重型商用车动力性和经济性计算仿真软件的开发研究

现代重型商用车的设计和改进中,需对整车的动力性与经济性进行较精确的模拟计算。故在建立数学模型的基础上,开发了基于MATLAB平台的重型商用车动力性与燃油经济性的仿真软件,并结合实例,进行了仿真计算,将其道路实验和计算仿真结果进行分析比较,验证了理论分析和软件开发的正确性。     

Performance development target setting of passenger car diesel engine

Setting engine emission targets to meet diesel car requirements is particularly important in engine performance development phase. Many researches are focused on associating vehicle performance with engine targets, but most work is done by testing, which is time and cost consuming, furthermore, the relationship of vehicle and engine will change when either engine or vehicle changes. A GT-Drive model to simulate New European Driving Cycle (NEDC) for passenger car is developed and calibrated by testing data, model precision is controlled within 5%. Time distribution of engine operating conditions when car running NEDC cycle has been analyzed, 10 critical major engine operating points are summarized according to running time proportion. Emission of NOx and smoke control regions containing these 10 points for target engine are set. Vehicle emissions are simulated and evaluated during engine development after engine performance test data are got, and engine combustion system layout and calibration are adjusted until vehicle targets are met. Vehicle is tested in chassis dynamometer finally, the testing results show a good agreement with the simulated results with an error of less than 5%, which proves that the emission value exchange of vehicle and engine is reliable. Performance target decomposition method for passenger car diesel presented can greatly shorten the development cycle and save costs.     

重型运输车柴油发动机电控系统研究与展望

介绍了重型运输车辆用大功率柴油机电控系统的研究现状、核心关键技术,如电子调速系统、高压共轨燃油喷射系统、废气再循环系统、冷却系统功率匹配和电子油门控制系统等,指出了重型运输车辆柴油机电控系统的发展趋势。     

Global energy consumption due to friction in trucks and buses

In this paper, we report the global fuel energy consumption in heavy-duty road vehicles due to friction in engines, transmissions, tires, auxiliary equipment, and brakes. Four categories of vehicle, representing an average of the global fleet of heavy vehicles, were studied: single-unit trucks, truck and trailer combinations, city buses, and coaches. Friction losses in tribocontacts were estimated by drawing upon the literature on prevailing contact mechanics and lubrication mechanisms. Coefficients of friction in the tribocontacts were estimated based on available information in the literature for four cases: (1) the average vehicle in use today, (2) a vehicle with today׳s best commercial tribological technology, (3) a vehicle with today׳s most advanced technology based upon recent research and development, and (4) a vehicle with the best futuristic technology forecasted in the next 12 years. The following conclusions were reached:

• •In heavy duty vehicles, 33% of the fuel energy is used to overcome friction in the engine, transmission, tires, auxiliary equipment, and brakes. The parasitic frictional losses, with braking friction excluded, are 26% of the fuel energy. In total, 34% of the fuel energy is used to move the vehicle.
• •Worldwide, 180,000 million liters of fuel was used in 2012 to overcome friction in heavy duty vehicles. This equals 6.5 million TJ/a; hence, reduction in frictional losses can provide significant benefits in fuel economy. A reduction in friction results in a 2.5 times improvement in fuel economy, as exhaust and cooling losses are reduced as well.
• •Globally a single-unit truck uses on average 1500 l of diesel fuel per year to overcome friction losses; a truck and trailer combination, 12,500 l; a city bus, 12,700 l; and a coach, 7100 l.
• •By taking advantage of new technology for friction reduction in heavy duty vehicles, friction losses could be reduced by 14% in the short term (4 to 8 years) and by 37% in the long term (8 to 12 years). In the short term, this would annually equal worldwide savings of 105,000 million euros, 75,000 million liters of diesel fuel, and a CO₂ emission reduction of 200 million tones. In the long term, the annual benefit would be 280,000 million euros, 200,000 million liters of fuel, and a CO₂ emission reduction of 530 million tonnes.
• •Hybridization and electrification are expected to penetrate only certain niches of the heavy-duty vehicle sector. In the case of city buses and delivery trucks, hybridization can cut fuel consumption by 25% to 30%, but there is little to gain in the case of coaches and long-haul trucks. Downsizing the internal combustion engine and using recuperative braking energy can also reduce friction losses.
• •Electrification is best suited for city buses and delivery trucks. The energy used to overcome friction in electric vehicles is estimated to be less than half of that of conventional diesel vehicles.

Potential new remedies to reduce friction in heavy duty vehicles include the use of advanced low-friction coatings and surface texturing technology on sliding, rolling, and reciprocating engine and transmission components, new low-viscosity and low-shear lubricants and additives, and new tire designs that reduce rolling friction.     

Work and speed based engine operation condition analysis for new European driving cycle (NEDC)

In order to evaluate fuel consumption and tailpipe emission of a vehicle, standard driving cycles are used to prescribe vehicle driving condition such as speed, gear shift, fluid temperature and so on. New european driving cycle (NEDC) has prevailed as the only driving cycle for emission and fuel consumption while Federal Test Procedure 75(FTP-75) mode is used in the United States. In South Korea, NEDC is applied for emission certification and FTP-75 mode is used for fuel consumption of a vehicle powered by diesel engine. Because these driving cycles are mixed of static phase (cruising and idle) and transient phase (acceleration and deceleration), they need to be transformed to static engine operation condition so that optimization is possible using engine dynamometer for each representative engine operation condition. This study set up two models to convert vehicle driving conditions to engine operation condition based on work which the engine should produce to follow the driving cycle and based on representative vehicle speed of NEDC. Accuracy of each model was compared with actual vehicle test result on a chassis dynamometer and the characteristics of each model were analyzed.     

电容器型混合动力货运车的开发

开发了一种采用电容型器的混合动力的中型货运车,该车装备了一新型高蓄能的电容,可以实现更高的效率和更低的废气排放。该种新开发的电容器能够提供比一般的商业用的强电容多一倍的能量。货运车系统包括新电容、电机、传统的柴油发动机和机械式自动变速装置。燃油经济性比传统的柴油机高1.5倍。此外,废气排放也达到了的TLEV标准。     

发动机飞轮螺栓的三维有限元计算分析

结合大功率柴油机性能强化的数值计算，针对螺纹连接几何形状和载荷条件的复杂性，建立了装配实体模型；在考虑柔性曲轴附加转矩的情况下，采用接触分析法对发动机的飞轮螺栓进行了三维有限元计算；得出了螺栓工作状态下最危险点发生的位置，考核了螺栓的疲劳强度安全系数，分析结果表明，螺纹连接是一种弹塑性模型。提出了发动机性能强化后螺栓连接的三种优化设计方案。     

Multidimensional engine modeling: NO and soot emissions in a diesel engine with Exhaust Gas Recirculation

The effects of EGR (Exhaust Gas Recirculation) on heavy-duty diesel engine performance, NO and soot emissions were numerically investigated using the modified KIVA-3V code. For the fuel spray, the atomization model based on the linear stability analysis and spray wall impingement model were developed for the KIVA-3V code. The Zeldovich mechanism for the formation of nitric oxide and the soot model suggested by Hiroyasu et al. were used to predict the diesel emissions. In this paper, the computational results of fuel spray, cylinder pressure, and emissions were compared with experimental data, and the optimum EGR rates were sought from the NO and soot emissions trade-off. The results showed that the EGR is effective in suppressing NO but the soot emission was increased considerably by EGR. Using cooled EGR, soot emission could be enhanced without worsening of NO.