| 摘要 |
<p>PROBLEM TO BE SOLVED: To obtain a method and an apparatus in which the pulsation of an air current can be measured without delay and precisely by a method wherein, on the basis of a flow-rate detection signal whose response delay is restored, a threshold value is detected and the direction of the flow of the air is estimated on the basis of the crossing of the threshold value with the flow-rate detection signal whose response delay is restored. SOLUTION: A microcomputer 40 compensates the response delay of a flow-rate detection signal which is obtained from a heat-ray probe 11 and which contains a response delay. It sets a threshold value on the basis of the maximum value and the minimum value of the detection signal whose response delay is compensated, and it judges a reverse-flow section. According to the judged reverse-flow section, the detection signal is compensated, and an air flow rate is measured precisely. That is to say, in order to reduce a measuring error at the pulsation of the air flow rate, the response delay of the flow-rate detection signal obtained from the heat-ray probe 11 is restored. A threshold value is computed on the basis of the detection signal whose response delay is restored. The direction of the flow of the air is estimated on the basis of the crossing of the threshold value with the detection signal whose response delay id restored. Thereby, a following-flow section is discriminated from the reverse-flow section without delay. A correction processing operation can be performed, and the measuring accuracy of an average air flow rate can be increased when a reverse flow is generated.</p> |
