数字输出型热膜式空气流量计的设计与实现  

Design and Implementation of Digital Thermal Air flow Meter

作　　者：杨文涛[1] 王婷旺 冯则坤[1] 刘长华 戴建飞 

机构地区：[1]华中科技大学光学与电子信息学院,湖北武汉430074 [2]南昌工控电装有限公司,江西南昌330001

出　　处：《仪表技术与传感器》2015年第3期33-35,59,共4页Instrument Technique and Sensor

摘　　要：针对目前国内数字输出型热膜式空气流量计设计较少的现状,设计了一种基于硅MEMS新型热膜式AFS07空气流量传感器和PIC16F1786微控制器的数字输出型车用空气流量计。详细分析了该空气流量计的工作原理和检测电路、恒温差控制电路的设计,通过PIC16F1786微控制器产生了ECU所需频率范围为1.8~11 k Hz、占空比50%的方波流量信号和频率为19 Hz、占空比可变的矩形波温度信号。在此基础上对样机进行了实验。实验结果表明：该样机实现了对不同流量气体和进气温度的检测,且具有良好的温度补偿功能;同时得出该空气流量计输出信号的周期与其对应信号的输出电压之间呈线性关系。Aiming at the problems that digital thermal air flow meters were decreasing,an automotive digital air-flow meter which was based on a new type of silicon MEMS sensor and PIC16F1786 microcontroller was developed. The working mechanism of air-flow meter,sensing circuit and constant temperature difference controlling circuit were analyzed in detail. A flow mass square wave signal with 50% duty ration,the frequency varying from 1. 8 k Hz to 11 k Hz,together with a 19 Hz-frequency varying-duty-ratio ambient temperature signal,which electronic control unit（ ECU） needs were generated. Experiments were done on prototypes,and the results show that air-flow meter successfully detects the varying air mass flow and the ambient temperature with temperature well compensated. What＇s more,the output cycle of signals generated by the air flow meter are linear with the output voltage of the sensor.

关 键 词：数字输出型 AFS07热膜式空气流量传感器 PIC16F1786 线性关系 

分 类 号：TH715[机械工程—测试计量技术及仪器]