摘要 |
A thermal type air flow meter includes a device for measuring an intake air flow rate by heating and controlling a heating resistor, and an analog-to-digital converter for digitizing an air flow rate signal of the air flow rate measurement device. The air flow rate measurement device inputs a reference voltage to the analog-to-digital converter so that the reference voltage can be converted from an analog signal to a digital signal, and the air flow rate signal can be corrected in accordance with the value of the reference voltage. A/D conversion of the air flow rate signal can be executed accurately even when the voltage of the reference voltage source of the A/D converter in an electrical control unit is fluctuating.
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