| 摘要 |
<p>PURPOSE: To provide a heat generating resistance type f1ow rate measuring apparatus by which the forward direction and the reverse direction of the flow of a fluid becoming a pulsating flow from a steady flow and becoming a pulsating flow provided with a backward flow are discriminated, which outputs a signal corresponding to the flow rate and whose accuracy is high. CONSTITUTION: At least two thermally sensitive resistors 2 which are installed so as to be adjacent on the upstream side and the downstream side are installed inside a first flow passage 302, and a subpassage 3 is constituted in such a way that it is composed of a second flow passage 304 in which the greater part of the flow rate of a fluid flowing into the first flow passage 302 from the forward direction flows and of a third flow passage 309 which guides a flow in the reverse direction to the thermally sensitive resistors 2. In addition, the entrance of the first flow passage 302 is formed to be of a saucer shape, and the exit of the second flow passage 304 is made parallel to a main flow so as to be of a shape in which an eaves-shaped protrusion has been formed on its upstream side. Thereby, a negative error due to the results of the measurement of the intake air flow rate of an internal combustion engine and due to a pulsating flow is eliminated almost completely, and a positive error due to a backward flow is reduced to about 1/10.</p> |
