【作者】 刘磊；

【导师】 马南琦；

【作者基本信息】 武汉理工大学 ， 轮机工程， 2008， 硕士

【摘要】 柴油机气缸排气温度的高低,是柴油机运行时必须监测的一个重要参数。船舶柴油机排气温度过高的原因是燃油在气缸中未能完全燃烧而造成其在排气管中二次燃烧。船舶柴油机排气温度过高影响柴油机的正常工作,如造成气阀烧蚀,增压器部件故障等:排气温度过高还会引起发动机活塞与气缸的气蚀磨损,使增压器的转速下降,而造成充气系数下降,不能正常工作等。本论文将传统的热电偶测温技术、遗传算法技术与单片机技术结合起来,设计了读数直观、准确并能进行自动和手动校准的数字式智能测温仪表。该仪表采用单片机芯片AT89C52作为微处理器,采用热电偶作为温度传感器,能够准确测量并显示柴油机12缸的排气温度,并能够实现温度超限报警。论文主要由热电偶数学模型的建立、智能测温仪表的硬件设计和智能测温仪表的软件设计三个部分组成。第一部分分析了热电偶和遗传算法的基本知识,设计了热电偶的信号调理电路,采用AD590解决了热电偶的冷端补偿问题。同时,建立了基于遗传算法的数学模型,解决了K型热电偶(镍铬-镍硅)的非线性问题。第二部分设计了智能测温仪表的硬件,设计了智能测温仪表的电路,该智能测温仪表由五个主要部分组成:测温电路、模数转换、电源、键盘输入及数码管显示,介绍了各组成部分的主要芯片,设计了其接口电路。第三部分设计了智能测温仪表的软件,采用模块化的程序设计方法,编写了适用于单片机的热电偶测温程序,解决了热电偶热电势与温度之间的非线性问题,减小了热电偶的氧化带来的测温误差,使得该智能测温仪表能够实现所需要的功能。更多还原

【Abstract】 The diesel engine air cylinder discharge temperature is a key parameter which must be monitored during the operation of diesel engine. The reason of ship diesel engine’s hyperpyrexia is the fuel’s second combustion in the exhaust pipe caused by its imperfect combustion in the air cylinder. The hyperpyrexia of ships diesel engine affects its normal work, such as distorting and breaking the exhaust pipe to leak air and becoming a hidden fire danger, simultaneously it also pollutes the engine room and influences staff’s normal work; The hyperpyrexia also causes the cavitations damage between engine piston and air cylinder and drops the rev of supercharger, then drops the charging coefficient, making it not in gear.Combining the traditional thermo-element temperature measurement technology, the genetic algorithm technology and the monolithic integrated circuit technology, this paper designs a digital intelligent temperature measurement device which can calibrate automatically and the manually and can be read directly and accurately. Adopting monolithic integrated circuit chip AT89C52 as the microprocessor, and thermoelement as the temperature sensor, this device can measure and demonstrate the 12 diesel engine cylinder’s exhaust temperatures correctly, and alarm the ultra temperature.This thesis is composed by three parts: the establishment of the thermoelement mathematical model, the hardware design of the intelligent temperature measurement device and the software design of the intelligent temperature measurement device. The first part analyzes the elementary knowledge of thermoelement and the genetic algorithm, designs the thermoelement signal recuperation electric circuit, and uses AD590 to solve the thermo-element cold end compensation problem. At the same time, it establishes a mathematical model based on the genetic algorithm, and solves the non-linear problem of the K thermoelement (nichrome - nickel silicon). The second part of the thesis designs the hardware and the electric circuit of the intelligent temperature measurement device. This intelligent temperature measurement device is composed of five main parts: The temperature measurement electric circuit, a/d conversion, the power source, the keyboard entry and the nixietube demonstration. It also introduces each part’s main chip, and designs its interface circuit.The third part designs the software of the intelligent temperature measurement device, introduces procedure compilation tool KeilC51, and takes modular the programming method, compiles suitable thermo-element temperature measurement procedure for monolithic integrated circuit, solves the non-linear problem between the thermoelement thermoelectric force and the temperature, reduces the temperature measurement error brought by the thermo-element oxidation, and accomplishes all the functions this intelligent temperature measurement device needed.更多还原