基于ARM的热式空气流量计的设计

Design of Thermal Air Flowmeter Based on ARM

针对传统空气流量计在测量汽车发动机进气量时存在精度低、响应慢等缺点,设计了一种基于ARM的热式空气流量计。系统基于恒温差的测量方法,当空气流经加热电阻时,利用加热电路维持加热电阻与环境温度的恒定温差,通过加热电阻上电流变化引起的电压变化来计算得到空气流量信号。实验结果表明,该流量计具有响应速度快、测量范围大、测量精度高等优点,综合测量误差小于1%,流量计的精度满足发动机的要求。

Aiming at the shortcomings of traditional air flowmeters such as low accuracy and slow response when measuring the intake air volume of automobile engines,a thermal air flowmeter based on ARM was designed.The system was based on a thermostatic differential measurement method.When the air flowed through the heating resistor,the heating circuit was used to maintain a constant temperature difference between the heating resistor and the ambient temperature,and the air flow signal was calculated by the voltage change caused by the change in the current on the heating resistor.The experimental results show that the flowmeter has the advantages of fast response,large measuring range and high measurement accuracy.The integrated measurement error is less than 1%.The accuracy of the flowmeter meets the requirements of the engine.