车用热膜式空气流量计分析与设计

摘要

针对目前国内车用热膜式空气流量计设计较少的现状,以某款模拟电路样机为研究对象,在分析样机加热控制电路、检测电路及传感探头结构的基础上,对样机进行了实验.结果表明,样机能检测不同流量的气体,并具有一定的温度补偿功能.样机正确反映了热膜式空气流量计的检测原理,直观显示了探头部分结构.同时,通过实验分析了模拟控制方法、检测电阻线性度等因素对样机热区性能的影响.最后,针对模拟控制电路存在的缺陷,基于汽车芯片提出一种数字化解决方案.研究为热膜式空气流量计的设计提供了参考,具有一定的工程意义和实用价值.%Aiming at less original design for automotive hot-film AFM (airflow meter)in china, with a prototype based on analog circuit as a study object,experiments of the prototype are performed afier analyzing the heating control circuit,detection circuit and sensor probe structure.The results show that the prototype can detect air with different flow with certain temperature compensation.The prototype has reflected correctly the detection theory of AFM and has revealed intuitively the structure of sensor probe as well Meanwhile ,some influence factors on the performance of the hot zone are also studied through experiments, such as analog control method,linearity of detection resistances and etcAt last,α digital solution based on automotive chips is proposed to settle faults existed in the analog cire uit.The study provides some references for the design and maintenance of AFM with certain engineering significance and practical value.