共查询到20条相似文献,搜索用时 437 毫秒
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Z. Zhang C. Zuo W. Hao Y. Zuo X. L. Zhao M. Zhang 《International Journal of Automotive Technology》2013,14(5):773-778
This paper discusses the necessity of using a transmission system to improve the energy efficiency of purely electric vehicles (EVs). The energy efficiency of an electric motor varies at different operating points to meet the output power demand. The three gear ratios of a transmission system can maintain the motor speed within a stable region with relatively high energy efficiency, while various vehicle speeds are needed. This work is based on a light EV prototype. The optimized gear ratios of this transmission result in a considerably reduced energy consumption of 9.3% compared with conventional EVs with single-speed reducers under the condition of the Urban Dynamometer Driving Schedule driving cycle. Thus, the transmission system is necessary to improve the energy efficiency of EVs. 相似文献
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Most hybrid vehicles employ the continuously variable transmission (CVT or eCVT) currently as their choice of the transmissions. Recently, an automated geared transmission (AGT) or dual clutch transmission (DCT) is being tried for some hybrid vehicles for the better fuel economy than the CVT hybrid. However, this AGT or DCT is using automated clutches which require the hydraulic power in addition to the slippage in the clutch plate invoking some energy loss as well as wear. Also, they require a motor with significant power to match to the engine power. The clutchless geared smart transmission (CGST) has no clutch and the clutch function is performed by a planetary gear system controlled by a motor-generator. The hybrid vehicles proposed here using CGST may have some merits in durability, fuel efficiency, and cost since they do not have clutches. The motor used for the clutch function can be also working for power merge with the engine in propelling the vehicle. The proposed hybrid system can be either mild hybrid or full hybrid by adopting a different capacity of battery with much smaller motor-generator due to the planetary gear system compared to the other type hybrid vehicles. In this study, the prospects of newly proposed CGST hybrid system are examined in practical aspects compared with AGT hybrid or DCT hybrid systems. 相似文献
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Meng Li Michael Khonsari Ruzhou Yang 《International Journal of Automotive Technology》2018,19(3):473-488
The torsional vibration generated during clutch engagement directly affects the shifting quality of automatic transmissions, where the noise source stems from both the clutch and the gear set. To predict the dynamical response and driveline oscillation, a comprehensive mathematical model of the vehicle powertrain equipped with automatic transmission is developed with consideration of nonlinearities in the clutch and the planetary gear set. For the clutch, the dynamics of stickslip is described for the transition between the slipping to locked states. The gear backlash model is used to analyze the rattle noise of the planetary gear set. Based on extensive powertrain simulations for the clutch engagement process, the magnitude of vibration propagation in the driveline are predicted to identify the primary factors of noise generation. 相似文献
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H. Yang B. Kim Y. Park W. Lim S. Cha 《International Journal of Automotive Technology》2009,10(3):381-390
In recent studies, various types of multi-mode electric variable transmissions for hybrid electric vehicles have been proposed.
A multi-mode electric variable transmission consists of two or more different types of a planetary gear hybrid powertrain
system (PGHP), which can change power flow type using clutches to improve transmission efficiency. Input split systems are
generally used for the single-mode powertrain because of their overall superiority, but other power split systems such as
output split and compound split systems can be used in the dual-mode powertrain. In this study, we analyze the power transmission
characteristics of output split systems, and evaluate their fuel economies in the FTP72 cycle, acceleration performance, and
constant vehicle speeds. These results enable the selection of appropriate systems for a dual-mode powertrain. 相似文献
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为解决传统电控机械式自动变速器(AMT)换挡过程中的动力中断问题,同时提高整车动力性与经济性,提出一种将行星机构安装在AMT输入端构成的新型自动变速器(N-AMT),并对N-AMT基本结构进行详细介绍,同时就驻车、起步和换挡过程中行星机构工作模式进行详细分析。首先根据最大、最小传动比、挡位数和相邻速比的设计要求对N-AMT进行速比初步设计,然后结合AMT换挡和双离合(DCT)换挡各自特点,以动力性为约束,NEDC工况最佳燃油经济性为目标进行遗传算法速比优化设计。利用速比优化设计方法进行不同挡位N-AMT方案设计,并根据动力学关系建立整车模型,对N-AMT进行动力性与经济性分析。综合考虑不同挡位数方案的分析结果和变速器结构成本等因素,确定8挡N-AMT为最终设计方案。最后对8挡N-AMT进行台架、起步和顺序换挡试验。研究结果表明:8挡N-AMT的NEDC循环工况油耗为6.38 L·(100 km)-1,较5挡AMT原型车工况油耗6.95 L·(100 km)-1减少了8.86%;N-AMT可以有效消除部分挡位间动力中断的问题,在30%加速踏板开度下,8挡N-AMT的起步时间为1.55 s,较5挡AMT起步时间1.61 s减少了3.7%,整车动力性得到提高;N-AMT换挡时间保持在1.05 s以内,且换挡平顺性较好。 相似文献
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液压传动柔性特征适用于起步工况,机液传动高效无级调速特征适用于作业工况,机械传动高效变速特征适用于转场工况。分析集液压传动、机液传动和机械传动为一体的多模式机液复合传动装置的设计思路在汽车工程上具有理论研究意义和实际应用价值。研究了机液复合传动的功率流传递机理,分析了换挡机构处于功率分流机构、复合传动机构、功率汇流机构和后置换挡机构一处或多处时,分段式机液传动装置各自的性能特征。研究结果表明:功率分流传动方式多适用于中小功率车辆,且马达转矩与传动装置输出转矩比值保持不变;功率汇流传动方式多适用于大功率车辆,使小功率液压件传递大功率成为可能,并能够在输出端起到减速增矩的效果;功率分流和功率汇流互换的传动方式可通过控制行星齿轮双接口及后置换挡机构,保证机液复合传动在不同速度分段中的高效运行;当换挡机构在行星齿轮之间时,可在2个不同区段改变行星齿轮机构的特性参数,使得在整个工作区范围内保持合理的功率配额;当采用多段式行星齿轮功率汇流传动方式时,后置换挡机构扩大了传动装置转速和转矩的覆盖范围。根据上述5类机液传动设计思路,提出对应的多模式机液复合传动装置设计方案。以一款用于扫地车的机液复合传动装置为研究对象,进行运动学和动力学分析,确定相关参数,绘制调速曲线和效率特性曲线,并对其挡位切换优化问题做了简要介绍。该方案充分利用液压传动的无级调速性能和机械传动的高效变速性能,较好地满足了车辆起步、作业和转场工况的要求。 相似文献
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汽车齿轮齿条式转向器变速比传动的研究 总被引:3,自引:0,他引:3
对汽车转向系杆系的力学特性进行了分析,指出了齿轮齿条式转向器采用定速比传动的缺点及采用变速比传动的必要性。讨论了手动及动力转向器变速比曲线的选择原则及方法。剖析了国外为夏利轿车转向器设计的速比曲线,给出了其解析表达式。 相似文献
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杠杆法使得对行星机构的分析变得简单直观,该方法还可用于行星变速器传动方案可能性的分析.文章对行星机构与等效杠杆之间的关系进行了分析,得出行星机构可以用等效杠杆进行分析的结论,推导出了用等效杠杆法分析行星变速器时各档位传动比的计算公式. 相似文献
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杠杆法使得对行星机构的分析变得简单直观,该方法还可用于行星变速器传动方案可能性的分析。文章对行星机构与等效杠杆之间的关系进行了分析,得出行星机构可以用等效杠杆进行分析的结论,推导出了用等效杠杆法分析行星变速器时各档位传动比的计算公式。 相似文献
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工程机械传动机构行星轮系的建模与仿真 总被引:1,自引:1,他引:1
进行工程机械车辆传动机构中行星轮系基于结构与机构设计以及运动仿真的研究。运用Pro/Engineer的实体建模、虚拟装配和机构仿真功能,对齿轮进行了参数化设计,与相关零件虚拟装配形成了行星轮系;并对轮系进行了运动仿真,有效提高了产品的设计、开发速度,可降低研制费用,为工程机械车辆零部件的CAD、各种技术分析和无纸自动化制造奠定基础。 相似文献