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 having a high measuring accuracy, in which sensitivity is enhanced by an operating means using sensors having different output characteristics and employing a digitized signal, and the sensitivity and temperature can be corrected easily depending on the flowing direction of fluid. The measuring apparatus comprises at least one heating resistor disposed in gas fluid, resistance bulbs formed at an upstream part and a downstream part of the heating resistor in the flow direction of the fluid, means for outputting at least two signals related to the flow rate of the fluid, means for quantizing outputted values, and means for operating the flow rate based on a quantized signal.