| 摘要 |
PURPOSE:To improve reliability without being influenced by a secular change by dipping an optical fiber whose tip is bent nearly in a U shape in the fluid contained in an oil receiving pan, and judging the kind of the contained liquid by a control circuit from the large/small difference in the amount of photodetection of a photodetecting element. CONSTITUTION:A light emitting diode 19 in an optical controller 21 emits light under the control of a main controller 22 at the beginning of heating and during the heating and projects the light upon one end part of the optical fiber 15 in a protection cable 14. This light is guided through the optical fiber 15 to reach a phototransistor 20 according to the kind of the liquid contained in the oil pan 5. The optical fiber 15 has a bent part 15a, so the light is refracted according to the kind of the liquid contacting it. The phototransistor 20 detects the amount of photodetection in the form of a voltage value and sends its signal to the main controller 22. |
