Thermal air flow rate measuring apparatus and its flowmeter and internal combustion engine and thermal air flow rate measuring method using it

摘要

A thermal air flow rate measuring apparatus of great precision wherein sensitivity is enhanced by sensors having different output characteristics and an operating device employing a digitized signal. The sensitivity and temperature can be corrected easily depending on the flow direction of fluid. The measuring apparatus includes at least one heating resistor disposed in a gas fluid, temperature detecting resistors formed at an upstream part and a downstream part of the heating resistor in the flow direction of the fluid, a device for outputting at least two signals relating to the flow rate of the fluid, a quantizing device for quantizing the output values, and an operating device for operating the flow rate based on the quantized signals.