| 摘要 |
PURPOSE:To improve the reliability of a needle valve lift amount detector by a method wherein a photoconductive means is provided in the fuel injection valve and light, reflected from a direction different from the moving direction of a moving member, is projected into the light receiving end face thereof. CONSTITUTION:A needle valve 3 moves upwardly against a spring 8 when it receives fuel oil pressure in an oil reservoir 10 and moves downwardly to close the valve when the supply of high-pressure oil is stopped. In this case, a rod 15 moves together with and by the same amount of the movement of the needle valve 3 and a relative motion is caused between the bundle 18 of optical fibers and the tip end of the rod 15 in accordancd with the lifting motion of the needle valve 3. The bundle 18 of the optical fibers project parallel beams from a light source from the sidewise direction against the tip end of the rod 15 through the bundle 22 of optical fibers, receives the light of reflection, having a strength in accordance with the amount of lift of the needle valve from the end facd 20 to introduce it into a photoelectric converter through the bundle 21 of optical fibers and outputs the amount of lift as an electric signal. According to this method, the resistance to vibration of the valve may be improved, the length of gap between the moving member and the light receiving end of the photoconduction means may be adjusted easily and the reliability of the valve may be improved. |
