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毕业设计（论文）说明书题目名称：空气流量信号处理系统设计院系名称：机电学院班级：车辆091班学号：200900374102学生姓名：赵蕊指导教师：姜春英2013年05月空气流量信号处理系统设计Thedesignofairflowratesignalprocessingsystem院系名称：机电学院班级：车辆091班学号：200900374102学生姓名：赵蕊指导教师：姜春英2013年05月论文编号：200900374102I摘要空气流量计是发动机中的一个重要部分，，是测量发动机吸入空气量多少的传感器，空气流量计能够把空气流量的大小转变为电信号，空气流量计将吸入的空气量转换成的电信号送至发动机ECU（电控单元），进气量的电信号被用来计算基本喷油持续时间和基本点火提前角。本课题的任务是为汽车发动机空气流量计设计出一套简明的信号采集系统，使人们能够清楚的认识到空气流量计工作过程。本设计介绍了空气流量计的工作原理，工作方式。以及根据空气流量计的原理和硬件结构，使用相应的软件进行系统编程,并加以模拟。软件编程主要分为两部分：A/D转换，SCI通信。除此之外，还要编写一个用labview软件做出来的界面。通过A/D转换将空气流量计的电压信号转换为可识别的数字信号，用SCI通信将数据传递给电脑。然后用labview编译的界面将数据的变化显示出来。通过模拟实验给单片机一个模拟的变化的电压信号使空气流量计中的电压变化在界面上显示出来。关键词：空气流量计A/D转换SCI通信IIABSTRACTAirflowmeter，whichisanimportantpartoftheengine,isameasureofhowmuchtheengineintakeairquantitysensor.Airflowmetertakesthesizeoftheairflowintoanelectricalsignal,andsendsittotheengineECU(electroniccontrolunit).Electricsignalofintakeairusedtocalculatethebasicfuelinjectiondurationandbasicignitionadvanceangle.ThetaskoftheprojectistodesignaconcisesignalacquisitionsystemforautomotiveengineairflowmetersothatpeoplecanclearlybeacquaintedwithAirflowmeterworkingprocess.Thisdesigndescribestheairflowmeterworksandwork.Andinaccordancewiththeprinciplesofairflowmeterandhardwarearchitecture,usetheappropriatesoftwaretodosystemprogramming,andmakesimulations.Softwareprogrammingisdividedintotwoparts:A/Dconverter,SCIcommunication.Inaddition,wealsoneedwriteainterfacewithlabviewsoftware.TheA/Dconversionoftheairflowconvertavoltagesignalintoadigitalidentificationsignal,andtheSCIcommunicationpassdatatothecomputer.Thentheinterfacecompiledwithlabviewwilldisplaythechangeofthedata.ViaSimulationexperiment,givingSCMavaryingvoltagesignaltomakethechangofairflowmeterinthevoltagedisplayedintheinterface.Keywords:airflowmeterA/DconversionSCIcommunication1目录摘要.................................................................................................................................IABSTRACT.........................................................................................................................II1绪论................................................................................................................................11.1前言............................................................................................................................................11.2空气流量计系统介绍.............................................................................................................11.3空气流量计国内外的现状和趋势.........................................................................................22硬件设计........................................................................................................................42.1空气流量计的基本组成...........................................................................................................42.1.1、质量型空气流量计：..................................................................................................42.1.2体积型空气流量计.........................................................................................................62.2MC9S12XS128内部结构、主要特性....................................................................................72.3MAX232...................................................................................................................................83软件设计......................................................................................................................113.1CodeWarrior软件简介.........................................................................................................113.1.1项目调试场景..............................................................................................................113.1.2CodeWarrior中项目的基本管理和设定....................................................................123.2系统流程.................................................................................................................................143.3A／Ｄ转换模块设计............................................................................................................163.4SCI模块设计............................................................................................................................233.5labview软件设计....................................................................................................................273.5.1labview软件简介.........................................................................................................273.5.2labview应用程序构成.................................................................................................273.5.3前面板..........................................................................................................................273.5.4流程图..........................................................................................................................273.5.5图标连接器................................................................................................................284调试过程...........................................................................................