基于全可变气门汽油机进气量测量和控制问题研究

基于全可变气门运动机构的气门参数控制燃烧技术是改善传统SI汽油机燃油经济性,提高动力性和降低排放的最为有效的途径之。但是这也对发动机进气量的测量和控制提出了更高的要求。本文通过仿真和试验相结合的方法,对基于全可变气门机构汽油机进气量测量和控制问题进行了探讨和研究。     

手机触摸屏抗跌落仿真分析

跌落试验是手机产品可靠性试验的一个重要测试项目,一般在产品开发后期进行.采用有限元仿真分析可以大大降低开发成本,缩短开发周期,提高产品开发速度.利用Abaqus对处于开发阶段的手机触摸屏抗跌落性能进行数值仿真分析,研究跌落过程中触摸屏的受力情况,为造型设计师和结构工程师提供相应的设计参考.     

产品开发过程支持系统的设计与实现

提出一种产品开发过程支持系统的体系结构,不仅支持过程的建模和执行,也实现了对过程的度量、分析、改进和异常处理的支持。研究了过程度量、过程仿真、过程改进和异常处理技术,设计和开发了相应的子系统。整个系统可以用于分布式异构环境中,可以很好地支持产品开发过程的管理与改进,同时能与其他系统进行集成。     

针栓式变推力火箭发动机内流场数值仿真研究

发动机推力室的工作过程直接影响到发动机的性能,在设计过程中,从理论上分析推力室内的燃烧流动过程具有非常重要.通过数值仿真,可以大大缩短发动机的研制和改进设计周期,减少研制经费.针对自燃推进剂针栓式变推力液体火箭发动机燃烧与流动的特点,借助CFD计算软件FLUENT,采用标准k-ε湍流模型及有限速率化学反应模型,对采用针栓式喷注器的变推力液体火箭发动机的推力室喷雾燃烧过程进行了数值仿真.计算结果得到了压强分布,温度分布,牛成物的摩尔分数分布,粒子轨迹分布、流强、混合比分布以及流动码赫数分布等,并对流场结构和影响发动机性能的喷注器参数进行了分析.数值计算结果可为变推力发动机喷注器和推力室的设计和优化提供参考.     

基于系列化配置原理的产品设计技术研究

在分析零件事物特性表的基础上,提出了基于系列化配置原理的产品设计技术.分析了使用该技术的产品开发的一般流程.研究了将产品配置和工艺配置在同一配置表中的存储技术;从三维CAD产品模型中进行特征提取的算法;零件工序简图的自动生成技术等关键技术和算法.以发动机气门产品为研究对象,使用UML的包图设计了发动机气门产品设计系统的组件模型,基于该组件模型和SolidWorks 三维CAD平台,使用Visual C 6.0实现了原型系统.     

H∞回路成形方法在航空发动机控制中应用及验证

引入了基于频域理论的H∞回路成形方法对航空发动机进行控制器设计,有效地克服了类似于LQG的传统时域方法设计过程不透明的缺陷;为了提高控制器设计效率和准确性,在设计过程中,设计了一种能自动搜寻满足要求的权函数参数的方法,同时对传统的控制结构进行了改形,改善了控制器性能;为更充分对控制器性能进行验证,在设计的航空发动机数控系统快速原型化实时仿真平台上进行了仿真,证实了所设计的改型后的H∞回路成形控制器在航空发动机控制上所具有的良好的性能。     

面向飞行仿真的涡扇发动机转速工程模型研究

通过对涡扇发动机总体性能参数的相互影响机理进行分析,建立了标准大气条件下涡扇发动机转速与飞机的飞行高度、飞行速度、油门杆位置的模型。应用相似性理论建立了适应不同大气条件下的发动机转速模型,并进行仿真分析。通过仿真数据与实际的发动机性能数据比较,结果表明基于总体性能建模方法设计的发动机转速模型的仿真结果与实际数据的误差在0.5%以内,上述方法对仿真精度的提高具有重要参考意义,同时可推广应用于发动机推力、油耗等模型的设计。     

基于Simulink的航空发动机控制律设计与仿真

在航空发动机数控系统设计过程中,计算机仿真技术得到了广泛应用。基于计算机仿真技术,利用Matlab/simulink软件开发数字仿真平台,在某型涡桨航空发动机数控系统方案设计过程中,进行了模型的响应分析,设计了控制规律并进行仿真验证;根据仿真结果,改进设计了前馈补偿环节,并进行了仿真验证;搭建了该型发动机的全数字仿真环境,对控制规律进行仿真验证。通过数字仿真验证了控制规律的可行性,指导了数控系统方案设计。     

面向虚拟数字样车开发的整车模态分析

一、引言 将ＣＡＥ这样的数字样机技术用于汽车新产品的开发，是现代汽车产品开发的重要手段之一，它能在新产品的设计阶段评估出它的性能，并指导设计工程师进行产品的优化设计，产品开发的一次成功率。汽车车身的性能是整个汽车产品的重要组成部分，汽车车身的性能决定于其结构的动态特性，模态分析是车身结构动态特性分析的基础，车身结构的自然频率能够用来评价车身与汽车行驶中各种振源（如发动机，路面不平度引起的随机激励）之间的动态干扰，避免共振的发生，车身模态振型可以用来确定对结构的改进措施，也可以应用到试验中去，在模…     

车辆仿真设计多属性开发平台LMS Virtual．Lab

LMS Virtual．Lab第七版不仅在各分析模块中增加了新功能,也对原有产品的技术效率和精度给予提升,进一步提升产品开发中对真实性能仿真及预测的效率及可靠性,为车辆仿真设计提供了一个强大的多属性开发平台。     

A comparative study on subjective feeling of engine acceleration sound by automobile types

To achieve marketing success, automobile companies are constantly striving to develop design elements that can create effective experiences for customers and establish their brand identity. Among the various design elements, engine sound is an important feature, which has been widely studied to understand the subjective feeling of the sound quality. This study aims to identify the representative affective variables of engine acceleration sound based on different vehicle types, and analyze their relation with psychoacoustic parameters. Affective adjectives were collected from previous researches and used to evaluate the engine acceleration sounds of different vehicle types, including 14 sedan cars and 10 sports cars, which were selected for the experiment. The third gear wide open throttle sounds of each automobile were recorded and evaluated by 36 adults. To quantify the representative affective variables, four psychoacoustic parameters namely loudness, sharpness, roughness, and tonality were utilized. The results showed there are two representative affective variables namely “comfort” and “sportiness”, which are significantly different across the vehicle types. The regression models for the affective variables showed distinct differences in the vehicle types. Furthermore, the results showed that the subjective feelings for engine acceleration sound depends on the vehicle type. The results of this research can be used to develop engine acceleration sounds that optimize subjective feelings for various vehicle types.     

混合动力电动汽车发动机转速智能控制系统设计

发动机是混合动力电动汽车动力设备的心脏,为了保证混合动力电动汽车可以快速稳定地运行,需要对其转速智能控制系统进行设计;使用当前控制系统智能控制混合动力电动汽车发动机转速时,无法快速检测到发动机转速,难以达到最佳的智能控制结果;为此,基于软切换提出Bang Bang-神经网络PID的混合动力电动汽车发动机转速智能控制系统设计方法;混合动力电动汽车发动机转速智能控制系统以Mcs-51系列8751单片机为核心系统,检测混合动力电动汽车发动机转速的数字信号,同时控制D/A模拟信号的输出,并在LED显示器上显示发动机转速数字信号,以PWM调制器放大混合动力电动汽车启动时发动机产生的PWM波,将放大后的PWM波供给电力发动机,再以分频填充脉冲装置测量混合动力电动汽车发动机转速,通过Bang Bang-神经网络PID算法计算出混合动力电动汽车发动机转速误差,达到实时控制混合动力电动汽车发动机转速的效果;实验仿真证明,所提设计方法保证了发动机转速的快速性和平稳性。     

基于MSC Adams/Engine的发动机悬置系统优化设计通用模块

为有效降低发动机产生的振动向整车传递,运用MSCAdams／Engine的参数化建模和二次开发功能建立发动机悬置系统优化设计通用模块．该方法能针对不同类型发动机快速进行参数化建模、悬置系统优化及优化结果评价,有利于缩短产品开发周期、降低产品开发成本．     

Speed planning and energymanagement strategy of hybrid electric vehicles in a car-following scenario

The development of intelligent connected technology has brought opportunities and challenges to the design of energy management strategies for hybrid electric vehicles. First, to achieve car-following in a connected environment while reducing vehicle fuel consumption, a power split hybrid electric vehicle was used as the research object, and a mathematical model including engine, motor, generator, battery and vehicle longitudinal dynamics is established. Second, with the goal of vehicle energy saving, a layered optimization framework for hybrid electric vehicles in a networked environment is proposed. The speed planning problem is established in the upper-level controller, and the optimized speed of the vehicle is obtained and input to the lower-level controller. Furthermore, after the lower-level controller reaches the optimized speed, it distributes the torque among the energy sources of the hybrid electric vehicle based on the equivalent consumption minimum strategy. The simulation results show that the proposed layered control framework can achieve good car-following performance and obtain good fuel economy.     

基于动态模拟技术的混动车辆发动机电控单元检测系统设计

电控单元是混动车辆发动机中的重要组成部分,对于发动机以及混动车辆的行驶性能产生直接影响,为保证电控单元的运行正常,利用动态模拟技术,优化设计了混动车辆发动机电控单元检测系统。改装温度、转速等传感器设备以及信号处理器设备,调整系统电路的连接方式,实现硬件系统的优化。利用动态模拟技术模拟混动车辆发动机电控过程,结合不同故障类型下电控单元的运行特征,设置系统的检测标准。采集电控单元输出信号,从时域和频域两个方面提取信号特征,最终通过特征匹配确定电控单元状态、故障类型以及故障位置,实现系统的电控单元检测功能。综合混动车辆发动机的三种运行场景,通过系统测试实验得出结论：与传统检测系统相比,优化设计系统的漏检率和误检率分别降低了2.59%和2.05%,由此证明优化设计系统具有良好的检测功能。     

Wheel slip control for antispin acceleration via dynamic spark advance

One of the problems that might occur during acceleration is wheel spin. While the wheels are spinning, the driving force on the tires reduces considerably and the vehicle cannot speed up as desired. It may even become very difficult to control the vehicle under these conditions. The acceleration characteristics of a vehicle can be improved without changing its physical capabilities with a suitable engine control algorithm that has no additional sensor inputs. This paper presents several control strategies for the wheel slip control problem. The torque output of an engine is modulated to prevent the wheel spin caused by rapid increases in the throttle input. The spark time is varied dynamically to adjust the engine torque and therefore the problem is often referred to as dynamic spark advance (DSA). Variable structure control theory is used for the controller design purposes and simulation results are provided.     

汽车下护板对发动机舱散热性能的影响

为提高汽车发动机舱的散热性能,通过计算流体力学数值仿真研究汽车下护板对整车散热性能的影响。研究表明：在高速工况下,增加下护板后格栅和冷却模块进气量增加;在高负荷工况下,下护板可改善发动机舱的空气温度分布形态。下护板开口可增加冷却模块进气量,不开口时舱内温度较低,所以在整车设计时应综合考虑散热量和热害。下护板能明显减少风阻,但开口会减弱其效果,因此设计时应多方面考虑。     

Automotive engine FDI by application of an automated model-based and data-driven design methodology

Fault detection and isolation (FDI) in automotive diesel engines is important in order to achieve and guarantee low exhaust emissions, high vehicle uptime, and efficient repair and maintenance. This paper illustrates how a set of general methods for model-based sequential residual generation and data-driven statistical residual evaluation can be combined into an automated design methodology. The automated design methodology is then utilized to create a complete FDI-system for an automotive diesel engine. The performance of the obtained FDI-system is evaluated using measurements from road drives and engine test-bed experiments. The overall performance of the FDI-system is good in relation to the required design effort. In particular no specific tuning of the FDI-system, or any adaption of the design methodology, was needed. It is illustrated how estimations of the statistical powers of the fault detection tests in the FDI-system can be used to further increase the performance, specifically in terms of fault isolability.     

Spatial to kinematically determined structural transformations

To understand the building design process and to help designers involved, the idea of a research engine has been developed: In this engine cyclic transformations take place between spatial and structural building designs. With this engine, a design process can be studied closely and subjected to improvement, and designers can be supported. To develop the engine, in this paper a part of it is studied, namely the transformation from spatial to structural design, which can be divided into four sub transformations: (1) from spatial design to structural topology; (2) from structural topology to mechanical model; (3) from mechanical model to finite element model; (4) from finite element model to design recommendations. For the first sub transformation, two different techniques are presented: Spatial–Structural Transformation Rules and Element Selection. For the second sub transformation, also two techniques are presented: Element Approach and System Approach. Where possible, data models in EXPRESS and process models in IDEF0 are used. For the third and fourth sub transformation, new procedures have been developed using data models in EXPRESS. To test the data and process models for all four sub transformations, a simplified two-storey building, derived from a real six-storey apartment building, is used as case study. It can be concluded that the developed sub transformations function well, related to their application in the research engine, and that their development raises new research questions that have to be solved in the near future.     

汽油Mn杂质对氧传感器特性的影响

氧传感器是闭环控制的汽车发动机电系统的核心部件之一。利用氧传感器检测汽车尾气成分,调节空燃比,可以获得较高的汽油燃烧效率和较好的三元催化系统的净化效率。使用过程中,汽油中的杂质会影响氧传感器的性能。试验研究了汽油中Mn杂质对氧传感器性能的影响。结果表明：Mn杂质严重影响氧传感器的性能。Mn杂质沉积在传感器表面,与铂电极发生反应,导致传感器失效,从而导致排放尾气的净化率降低。