| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a thermal air flowmeter capable of performing a highly accurate flow rate measurement with a low-cost configuration even when a pulsating flow accompanied with a backflow occurs.SOLUTION: The thermal air flowmeter constitutes a bridge circuit including a heating resistor 6, and includes a bridge circuit 1 for supplying current to the heating resistor 6 so that the temperature of the heating resistor 6 is always set higher than the temperature of an intake air detected by an intake air temperature detection resistor 9 by a predetermined temperature and further includes: a differential amplifying part 2 for amplifying voltage depending on a temperature difference between an upstream heating resistor 61 and a downstream heating resistor 62; and a subtraction processing part 3 for subtracting a constant multiple of an output voltage Vd1 of the differential amplifying part 2 from an output signal Vm and for outputting a correction output signal Vout in a thermal air-flow sensor for outputting the output signal Vm corresponding to an intake air-flow on the basis of a value of the current supplied to the heating resistor 6.</p> |
