【作者】 叶香美；

【导师】 樊啟洲；

【作者基本信息】 华中农业大学 ， 农业机械化工程， 2005， 硕士

【摘要】 随着能源日益紧张,人们对驾驶柴油机时的舒适性日益重视,有关发动机冷却水温的研究得到了越来越多科研机构的重视。因为冷却水温与发动机的许多工作性能有着直接或间接的联系,如果冷却水温保持在最佳的温度范围内,不仅可以提高柴油机的动力性、减少废气的产生、还可以减少燃料消耗量、增强发动机工作平稳性。所谓最佳温度范围指冷却水温保持在此温度范围内,柴油机工作的整体经济性最好。而确定此最佳冷却水温范围,只有经过大量的检测实验和数据分析才能得出。检测冷却水温对柴油机零件磨损、功率、工作噪声、排气质量、润滑油质量、使用寿命、工作粗暴性等的具体影响,然后通过比较分析得出最佳温度范围。进行这些发动机性能测试实验的必备条件是有一个能检测并控制冷却水温在设定范围内的控制装置,研究并试制这样一个自动控制装置就是本课题的研究目的。 本课题所研制的控制器是以AT89S52单片机为检测控制中心的自动控制系统,通过向水箱加入冷水的方式,达到降低冷却水温的目的。通过控制器正面的5个按键可以进行温度范围的设定,4位数码管显示温度值,控制器背面有一个串行接口,用于控制器与计算机的通信。随着大规模集成电路技术的发展,特别是单片微处理器性能的提高,而价格又不断下降,使得设计这样一个控制装置成为可能。如何将单片机应用到柴油发动机的自动控制领域,也是当前柴油机自动化的焦点所在,本课题顺应了这种发展趋势,为柴油发动机冷却水温控制系统进一步深入研究创造条件。 本论文介绍了基于AT89S52单片机的水温控制器,它分为两大部分,硬件电路的设计和基于smith预估器补偿的PID控制软件的设计。文中分别介绍了温度测量电路、A/D转换电路、单片机及扩展口电路、键盘及显示、串行通信等硬件电路的设计方法和工作原理,详细介绍了控制算法选取依据、PID控制原理和控制软件的设计方法。通过仿真实验和模拟实验,得出所研制的控制器测量准确,反应灵敏,控制精度高,达到了预期的效果。更多还原

【Abstract】 Along with energy crisis, and people think more of comfort when driving car of diesel engine, more and more scientific research organization attach importance to it. Cooling water temperature is every important to diesel engine. If cooling water temperature can keep in the first-rank range of cooling water temperature, diesel engine’s power can be improved, and less exhaust gas produced, reduce fuel wastage, and engine work more calmly. So-called the first-rank temperature rank is diesel engine work best and cost least. In order to get this temperature rank we must do much experimentation and data analysis. First of all we should know the cooling water temperature affect piece part’s wear and tear, yawp, exhaust quality, lubricating oil, engine’s life etc, than we should deal with data that we got from experimentation, finally we can get the first-rank range of cooling water temperature. A necessary condition to do forenamed experimentations is a control who can make cooling water temperature in certain rang, and we can exchange rang. Design the control is my aim.Diesel engine’s cooling water temperature control based on 89S52 single chip microcomputer, in order to make cooling water temperature re fall down by putting cool water into water tank, and letting out hot water from water tank. We can change the temperature range by using the 5 keys on control, and the temperature displayed on the control. This control can send data to PC via serial communication.With the highly speedy development of Large Scale Integration Technology, especially with the enhanced performance and reduced price of single chip microprocessor, which make it possible to design such a control. How to apply the single chip microcomputer to diesel engine automation control realm, it becomes the one of questions for discussion in diesel engine automation. This work of this monograph adapts to the development tendency. It provides a necessary condition for more study on diesel engine.This paper introduces that the construction of hardware circuit and the design of PID control software of the system based on 89S52 single chip microcomputer. The principle and method of measurement circuit, precision and plifier circuit, A/D circuit, single and expand circuit, keyboard and show circuit, serial communication circuit is discussed. The principle and procedure of software design are described.更多还原