| 摘要 |
<p>PURPOSE:To obtain a good-response flow meter by employing a bobbin made of zirconia or glass fiber with small heat conductivity. CONSTITUTION:An electronic control fuel injection device for an internal combustion engine measures the flow rate of suction air by a heat generating resistor 1 installed in an air passage. Further, a driving circuit part controls the current of the resistor 1 and leads out the output voltage across the resistor 1 as a signal corresponding to the air flow rate. This resistor 1 uses partial stabilized zirconia as the material of the bobbin 21, and a cut 32 is formed after a platinum film 31 is vapor-deposited on the surface to adjust the resistance value. Then, the resistance body 1 is connected to support conductors 25 by brazing 24 and the whole body is coated with glass 33, which is dried at low temperature. Here, the bobbin 21 is superior in flexibility and absorbs heat stress generated at the time of measuring operation, and the mechanical strength is improved to prevent the flow meter from breaking down. Further, its heat conductivity is small, so the heat conduction to the conductors 25 is reduced and the ratio of the bobbin length and bobbin diameter is increased to improve the response. Further, same effect is obtained even by a bobbin made of glass fiber.</p> |
