| 摘要 |
PURPOSE:To obtain a mixing ratio sensor which does not require any temperature sensor for detecting environmental temperature by compensating the quantity of light emission of an LED and the critical angle by one photodiode for temperature compensation owing to temperature variation. CONSTITUTION:An internal space 22 which cover the outer peripheral surface 41 of a light-transmitting body 4 is a passage for the mixed liquid of petroleum fuel (gasoline) and alcohol. A light emission part 3 formed by fitting the LED 35 and a photodiode 36 for temperature compensation to a light emission part case 33 is provided at one end side of the light-transmitting body 4, and a light reception part 5 for measurement formed by fitting a photodiode 55 for measurement to a light reception part case 53 is provided at the other end side. Then, the quantity of light emission of the LED 35 is controlled by a light emission quantity compensating circuit so that the output of the diode 36 is constant and thus the output of the photodiode 55 is held constant, thereby compensating the critical angle depending upon temperature variation of the mixed liquid by a light reception quantity compensating circuit by varying the quantity of electric feeding to the LED 35. Consequently, the output voltage of a mixing ratio sensor 1 varies with the mixing ratio of the mixed liquid and never varies with temperature.
|
