| 摘要 |
<p>PURPOSE:To make a high reliability flow rate measurement possible by correcting the temperature dependency of fluid heat loss based on the electric signal according to the supply voltage to a bridge circuit and the electric signal according to the output voltage. CONSTITUTION:A heater 2 with a resistance value having temperature dependency and a temperature measurement body 3 are arranged in an air suction path 1 and a bridge circuit consisting of a standard resistance R2 connected in series to the heater 2 and a standard resistance R3 connected in series to the temperature measurement body 3 is constituted. The voltage impressed to the bridge circuit is V1, the output voltage of the heater 2 side input to a differential amplifier 101 is V2 and the output voltage of the temperature measurement body 3 side is V3. When the bridge is in a thermal equilibeium, if the bridge output V2 is known from the relation, V2=V3, then the resistance of the temperature measurement body 3 is obtained and the fluid temperature is calculated. An ECU7 for fuel control of an internal combustion engine has an A/D converter 8, a memory 9, an arithmetic circuit 10 and an output circuit 11, and outputs to a control means 12. By preparing a correction coefficient corresponding to fluid temperature in advance and receiving the output voltage signals V1 and V2 of the heat sensing flow rate sensor 6, the net flow rate of the suction air can be known.</p> |
