As an important parameter of the engine fuel injection and ignition time,the air mass flow affect the air-fuel ratio of engine directly.So,the air mass flow must be measured accurately.An automotive air-flow meter,which was based on MKE02Z32VLC2 microcontroller with 32-bit ARM Cortex M0+core,was developed.This paper made full use of its hardware re-sources such as FLASH,ADC,FTM and so on to design an air-flow meter for engine air intake by using the characteristics of di-rect measurement of air-flow meter.Aiming at the problem that the defect of the traditional air-flow meter of cars neglected the self-heating of the ambient temperature compensation resistance,a kind of modified circuit was proposed.An improved filtering al-gorithm was raised for the accuracy of signal acquisition.In order to solve the weak point of single signal output of traditional air-flow meter,the function of pulse output and analog output were designed.Experimental results demonstrate that the accuracy of modified air-flow meter meets the requirements of the engine.%空气流量作为发动机喷油量和点火时间的重要参数直接影响着发动机的空燃比,因此,空气质量流量必须准确测量.利用热式空气流量计直接测量空气流量的特点,提出以32位ARM Cortex M0+内核的MKE02Z32VLC2单片机为控制核心,充分利用其内部的FLASH、ADC、FTM等硬件资源设计了一款发动机进气空气流量计.针对传统车用流量计忽略环境温度补偿电阻自热效应的缺陷进行改进;为提高信号采集的精确性,提出改进型的滤波算法;设计的流量计输出模拟和数字信号解决传统流量计只输出单一信号而无法通用的缺点.实验测试表明,流量计精度满足发动机的要求.
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