【作者】 马康康；

【导师】 韩宗奇；

【作者基本信息】 燕山大学 ， 车辆工程， 2011， 硕士

【摘要】 发动机负荷率的大小是影响汽车燃油经济性的重要因素。汽油机负荷特性表明,负荷率低时,燃油消耗率高;负荷率高时,燃油消耗率低。一般发动机的排量是按照汽车的最大负荷设计的,因此在多数行驶工况下发动机的负荷率都比较低。本文采用“循环”、“交替”、“均匀”的停止喷油器工作的方法改变发动机的工作排量。使得大负荷时用大工作排量,小负荷时用小工作排量,这样既可以满足动力性要求,又可以提高燃油经济性。首先,本文简要介绍了发动机循环变排量的基本原理和实现方法,然后分析了模糊推理与控制理论及其在变排量中的应用,同时给出了循环变排量的几种工作模式,并对小排量的工作模式进行了改进;其次,着重研究了循环变排量的控制策略,给出了输入参数的模糊化级别以及汽车行驶工况的判断方法。设计出了不同行驶工况下循环变排量的控制策略。同时用MATLAB建立了多输入单输出模型,模糊识别了发动机工作排量。最后,设计制作了基于PIC16F886单片机的循环变排量控制器,编写了包含控制策略的程序,使得控制器可以自动选择发动机排量。然后,进行实车道路试验。试验结果表明,安装控制器之后的捷达轿车可以根据行驶工况自动选择发动机工作排量,并能够起到节省燃油和减少排放的效果。更多还原

【Abstract】 The engine load rate is an important factor of vehicle fuel economy. The load Characteristics of petrol engine indicate that when the load rate is lower, the fuel consumption rate is higher; on the contray, when the load rate is higher, the fuel consumption is lower. In generally, the engine power is desigened by the maximum load of vehicle, so the engine load rate is lower at most conditions.In this paper, the engine’s work displacement is changed by stopping the injector’s work alternately, circulated and regularly. This makes that using high displacement when the load is big, low displacement when the load is small,so it can not only guarantees the power requirement, but also improves fuel economy.Firstly, this paper introduces the basic theory and method of variable power displacement in circuitation(VPDC), analyzes fuzzy reasoning and control theory and its application on the VPDC. Also, it gives several work modes of VPDC and improves some small displacement’s work modes. Secondly, it puts emphasis on control stategy of VPDC, gives the fuzzy levels of input parameters, and designs the control strategies of VPDC under all kinds of driving conditions. In the meanwhile, the model of more inputs and one output has been given, also the engine power has been indentified fuzzily. Finally, the controller of VPDC based on PIC16F886 has been desigened, and the program which included control strategies has been writed. What’s more, the road tests have been done. The results prove that the controller which is fixed on the Jetta vehicle can choose the engine power according to the driving conditions automatically. Also the fuel consumption and discharge can be reduced.更多还原