| 摘要 |
<p>PURPOSE:To detect reverse flowing in the operating region of an engine in a low rotary-output zone, by arranging two heating resistors so as to face each other along a flow, and detecting the reverse flow based on the magnitude of an electric signal corresponding to the flow rate. CONSTITUTION:A first heating resistor 1 is a heat sensitive element obtained by forming a platinum thin film on a cylindrical ceramic bobbin. A second heating resistor 2 has the same characteristics and the same configuration. The resistors 1 and 2 are both arranged approximately vertically with respect to the direction of a flow 5. Temperature compensating resistors 3 and 4 are further provided. The calorific values of the two heating resistors 1 and 2 are compared 10 and the forward or reverse direction of the flow 5 is judged. The heating resistors having the same configuration and the same characteristics are used and controlled at the same heating temperature by amplifiers 7 and transistors 6. The calorific value in the first heating resistor 1 or the second heating resistor 2 is measured and the flow rate is obtained. By comparing the calorific values of both resistors, the flowing direction can be detected at the same time.</p> |
