【作者】 毕乾坤；

【导师】 程秀生；

【作者基本信息】 吉林大学 ， 车辆工程， 2004， 硕士

【摘要】 汽车的自动变速技术一直是人们追求的目标，是改善和完善车辆传动系统的一个重要方面。车辆自动变速器通常分为液力机械式自动变速器（Automatic Transmission，简称AT）、电控机械式自动变速器（Automatic Mechanical Transmisson，简称AMT）和机械式无级自动变速器（Continuously Variable Transmisson，简称CVT）。 电控机械式自动变速器具有结构简单，传动效率高、成本低、易制造的优点，特别适合我国车辆产业的现状，它的研究、开发和产品化被列为国家“九·五”科技攻关项目。 本文结合以往的研究成果，作了如下工作： 1 根据以往的评价方法，提出了换档规律的动态评价方法。换挡规律是指某两个排档之间自动换档时刻随控制参数变化的规律。在自动变速的车辆中，换档规律决定了自动换档汽车是否在最佳换挡点进行换挡，决定了汽车性能的发挥程度。换档规律对车辆的性能有着很大的影响，不同换档规律对车辆性能的影响也不同，因此希望通过对不同换档规律进行比较和评价，寻找更加有利于发挥汽车性能的换档规律，故对换档规律的评价就显的更为重要。该方法的基本原理如下： 1)动力性评价方法。设车辆在一定的行驶工况下加速到某一预定车速v所要花费的时间为t，而此车辆在此行驶工况下按发动机最佳动力性工作线行驶到预定车速v花费的时间为t₀，它们的比值t／t₀就反映了发动机动力性的利用情况，而对于不同的换档规律，t／t₀值越小也就表示其动力性要强于另一换档规律下的动力性，越接近1，也就表示其发动机动力性利用得越充分。 2)经济性评价方法。设车辆在某一行驶工况下行驶某一预定距离s所消耗的燃油量为Q_s,而按照车辆在行驶时输出功率Pe相等的原则求出按发动机最佳经济性工作线工作时行驶到预定距离s所消耗的燃油量为Q_s0，比值Q_s／Q_s0也就反应了发动机经济性能的利用情况，也能评价不同换档规律下的燃油经济性，其值越小就表示其经济性要好于另一换档规律下的经济性，越接近1也就表示发动机经济性能利用得越充分。吉林大学硕士学位论文 2换档重叠和换档循环分析 换档重叠和换档循环和车辆的换档特性密切相关，换档特性是指相邻两档在换挡过程中、各油门开度下，加速度与车速的关系、牵引力与车速的关系、以及油耗与车速的关系。也可称为车辆在换档前后轮胎上的驱动扭矩、加速度、油耗随油门开度和车速变化的特性。换档重叠值大小的确定主要是为了保证车辆不致因油门抖动或车速的微小下降而导致不正确的频繁换档，本文对换档时的车速下降和油门抖动作了初步研究。 3模拟仿真系统的建立 模拟仿真系统的编制采用了Microsoft VisualC十+进行了开发，路景的建模利用了MultiGen建模软件和openGvS软件实时生成，具有的主要功能如下: l)能够显示不同的工况的路景; 2)能够实现车辆行驶过程中的自动换档; 3)能够实时显示车辆行驶过程中的行驶参数如行驶距离、时间、车速、 加速度、档位、油耗等，并且这些数据都保存到文件当中，便于事后 进行处理分析。 4)能够针对不同的车辆进行模拟仿真驾驶，只需要在程序的开始录入汽 车的各种参数，包括发动机试验数据，车辆动力传动系参数等。 4 AMT仿真系统换档规律评价方法的验证 为了验证换档规律动态评价方法的可行性和相应的评价模拟系统的的准确性，本文以装有机械式自动变速器的桑塔纳2000型轿车的试验数据为基础不同换档规律在该模拟系统下进行不同换档规律的模拟评价与分析，同时通过己有的数据进行了相关的试验验证，证明其是可行的。 5换档循环的模拟仿真试验 在此模拟仿真系统下对装有机械式自动变速器的桑塔纳2000型轿车进行了换档循环试验，得出在经常行驶工况下基本上能达到驾驶员的要求，在比较恶劣的工况下换档循环发生的频率显著增加。 经过以上深入的研究和试验验证表明所提出的换档规律动态评价方法是可行的，换档规律动态评价模拟系统可以就换档规律对汽车燃油经济性和动力性进行动态评价，所得出的结论与实际相符。 尽管本文所提出的换档规律动态评价方法和建立的换档规律动态评价模拟系统是以机械式自动变速器的两参数换档规律为基本规律，但本文的研究对摘要于分析和评价其它型式的自动变速器的不同类型换档规律对汽车燃料经济性和动力性的影响都有一定的参考价值。更多还原

【Abstract】 The automatic transmission technology of automobile is always the target that people pursue. It is a important aspect to reform and perfect the vehicle powertrain. The automatic transmission of automobile is divided into AutomaticTransmission(AT),AutomaticMechanicalTransmisson(AMT),Conti nuously Variable Transmisson(CVT).Automatic Mechanical Transmisson have the advantages such as simple machinery.high efficiency ,low cost and easy manufacture.The research and production of it has been listed into national "9.5" tackle key item of science and technology.This text combines the former research, make the following work:1 According to the former evaluation method, put forward the dynamic evaluation method of shift schedule. Shift schedule is the regulation that the time of automatically shifting between two shift changes with the control parameter’s variety. As to the automatic transmission automobile, shift schedule decides whether the automobile shifts on the best shifting point, decides the exerting extent of the vehicle performance. Shift schedule has great influence on the performance of the vehicle, and different shift schedule has different influence, therefore we hope to look for the shift schedule which is of more benefit to develop the automoblie’s functions by comparing and evaluating the different shift schedules, so, the evaluation of shift schedule comes to more important. The basic principle of that method is as follows:1) The evaluate method of dynamical performance: Suppose the time which the we cost to accelerate the vehicle to certain pre-arranged speed v on some driving load is t, moreover according to the best engine dynamical curve the time that it takes to drive the vehicle to the pre-arranged speed v on the driving load is to.The ratio t/to reflects the utilizing condition of the engine dynamical performance. Otherwise to different shift schedule, it is reflected that the t/to value is less, the dynamical performance is better than one in other shift schedules, it is more approach 1,it shows that the utilization of the engine dynamical performance is better.IV2)The evaluate method of economy: Suppose the fuel quantity which the vehicle cost to run some distance s on certain driving load is Qs, moreover the fuel quantity which the vehicle cost to run to pre-arranged distance s in the best engine economical curve is Qso and we get by the principle that the vehicle output power Pe is equal. The ratio Qs/Qso reflects the utilizing condition of the engine economical performance. It can be used to evaluate the fuel economy in different shift schedules. The value is less, the economical performance is better than one in other shift schedules, it is more approach 1it shows that the utilization of the engine economical performance is better.2 the analyse of shift superpose and shift circle:Shift superpose and shift circle are connected close with shift schedule. Shift characteristic is the relation of acceleration and speed, traction and speed, fuel consume and speed in the course of shifting on each throttle opening. It is also the characteristic that the driving torque on the wheel, acceleration and fuel consume change with the throttle opening and vehicle speed before and after shift. The purpose of confirm the value of shift superpose is to ensure the vehicle couldn’t incorrect continual shift on the basis of the throttle wobble and the small fall of vehicle speed. This text makes pilot study to the fall of vehicle speed and accelerograph wobble in the course of shift.3 the setting of the simulation system.The simulation system is programmed by Microsoft Visual C++, MultiGen and OpenGVS are utilized in the building of the modeling of road vision. the main function it have is as follows:1) It can show the road vision on the different load.2) It can shift automatically during the vehicle running.3) It can show the parameter such as running distance, time, acceleration shift and fuel consume etc. on real time, and these data are saved into files in order to analyse la更多还原