DCT双离合器联合起步模式建模与仿真

对双离合器式自动变速器(DCT)的结构特点进行分析,建立起步过程的动力学模型.归纳车辆起步时离合器传递转矩和节气门开度的变化规律,实现发动机恒转速起步.制定1挡单离合器及双离合器同时接合的起步控制策略,并针对大油门急起步情况制定了2挡单离合器和双离合器起步控制策略.针对车辆爬行起步时容易造成摩擦片温度过高的缺点,制定双离合器交替滑磨的爬行起步控制策略,并应用积分分离PID算法仿真实现对目标车速的跟随.仿真结果表明,双离合器同时接合的起步控制策略使两个离合器共同分担总体滑磨功,有利于提高离合器寿命.     

纯电动汽车坡道自适应起步控制策略

以一款三相交流异步电机为动力源的纯电动汽车为研究对象,搭建了三相交流异步电机动力传动系统试验台,研究了三相交流异步电机在转速控制模式下的堵转特性,得到了不同转速偏差下的电机转矩响应规律。建立了纯电动汽车坡道识别模型和起步过程中各控制量的计算模型,提出了一种基于电机堵转特性的纯电动汽车坡道自适应起步控制策略,通过Matlab/Simulink软件建立了仿真模型,对不同坡道的上坡起步和下坡起步进行了仿真研究,结果表明,提出的起步控制策略能够较好地适应纯电动汽车的坡道起步。     

纯电动汽车加速过程中的驱动转矩优化控制策略

以纯电动汽车在加速过程中的驱动转矩为研究对象,提出了以加速踏板开度和电动机转速确定纯电动汽车基准转矩的方法.根据纯电动汽车在不同车速加速时对驱动转矩的需求不同,建立了以车速和加速踏板开度及其变化率为输入变量,转矩补偿增量为输出变量的模糊控制器,并对基准转矩进行转矩优化.针对纯电动车加速时,不同车速对转矩补偿增量的影响程度,设计了不同驱动转矩控制策略在相同加速踏板动作下的加速对比试验.结果表明:考虑加速时车速因素的转矩优化控制策略提高了纯电动汽车在中低车速时的加速动力性和高速时的加速操稳性.     

纯电动汽车驱动控制器研究与开发

 驱动控制器是电动汽车的核心部件,其性能的优劣直接关系着纯电动汽车的整车性能和传输效率。本文针对大中型纯电动汽车,研究开发了一款基于Freescale S12单片机的纯电动汽车驱动控制器。根据纯电动汽车的特殊要求和运行环境,给出驱动控制器总体设计方案,其中硬件电路包括电源模块电路、主控制器最小系统电路、信号调理模块电路、PWM输出电路、数据通信模块电路和IGBT驱动模块电路等;控制策略采用模糊自整定PID控制策略。对安装该驱动控制器的纯电动汽车进行道路试验,试验表明,该驱动控制器能够满足车辆复杂的行驶工况,纯电动汽车具有较好的加速性能和良好的速度跟随性,满足相关国家法规要求,控制器适用于各类大中型纯电动汽车。     

轮毂电动机驱动车辆电动机的失效安全性

针对四轮独立驱动轮毂电动机式电动汽车电动机失效后车辆存在的安全性问题,提出了一种新型电动机失效控制策略.首先,失效控制器检测每台电动机的失效因子,判断失效类型;其次,根据油门踏板开度和转向盘转角决定失效控制目标,迅速协调正常工作电动机的输出转矩,以满足车辆期望纵向力矩和横摆力矩的需求,保证车辆行驶的动力性和稳定性.利用Simulink软件搭建了7自由度轮毂电动机驱动车辆动力学模型,对提出的控制策略进行了仿真研究.结果表明:该算法能在油门踏板开度大且转向盘转角小时保证汽车的动力性需求;在油门踏板开度较小或转向盘转角过大时进行稳定性协调控制,改善了电动机失效后车辆的行驶稳定性.     

联式混合动力驱动系统的模糊控制与仿真

在分析了动力分配机构工作原理的基础上,研究了混联式HEV的能量管理与控制策略,建立了混合动力电动汽车的驾驶员、发动机及整车控制模型。用MATLAB软件SIMULINK仿真中的“Fuzzy”模糊控制工具箱对模型在起步加速工况进行了仿真,并与纯电动汽车进行了对比。结果表明,基于此控制模型的混合动力电动汽车的加速性和最高车速远大于同档次的纯电动汽车。     

电动汽车用异步电机弱磁控制综述

为满足纯电动汽车对宽调速范围的要求,文章分析研究了纯电动汽车用异步电机弱磁控制策略的研究现状,详细阐述了不同坐标系下异步电机的数学模型及矢量控制策略,并对宽调速范围区间进行了分类,综合比较了异步电机传统和新型弱磁控制策略的性能优点及存在的问题,研究结果表明,传统1/ωr弱磁策略适用于性能要求不高的异步电机驱动领域,而变期望电压弱磁控制策略在电动汽车上有较好的应用优势。     

回流式无级变速传动系统起步控制特性分析

在充分阐述回流式无级自动变速传动系统起步工作机理和各关键部件工作特性的基础上,建立了该传动系统的动力学仿真模型,制定出离合器自动接合的恒转速起步控制策略,并通过系统仿真分析对所制定的控制策略加以检验.结果表明:起步离合器从动盘存在转速快速提升的特性,在同等起步时间条件下,离合器起步滑摩功低于3 kJ,仅相当于传统车辆起步时产生的滑摩功的1/3.     

车用电液助力转向系统异步电机转差频率控制建模及仿真

本文针对纯电动汽车EHPS系统对助力电机的助力特性,研究电控单元在低速、中速及高速时的控制要求,提出了基于稳态模型的助力异步电机转速闭环转差频率控制策略,在Matlab/Simulink环境下,建立了系统仿真模型,仿真实验结果表明了所提控制策略的有效性.     

越野车辆AMT消除意外换挡及频繁换挡策略研究

提出了油门钝化方法,用于解决装备AMT变速器的越野车辆经常出现车辆意外换挡及频繁换挡的问题.讨论了油门钝化控制策略对解决意外换挡及频繁换挡问题的可行性及其影响因素,通过采用步进的方式对油门信号进行处理,可以有效屏蔽短时间内油门剧烈变换对车辆换挡的影响.设计了油门钝化控制策略及控制软件.实车试验结果表明,采用油门钝化控制策略的越野车辆意外换挡及频繁换挡的现象得到了有效控制.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that