| 摘要 |
PURPOSE:To prevent erroneous sensing of an ignition time sensor for use in detecting a combustion light optically by a method wherein a filter of which optical transmission factor is decreased in response to an increase in an amount of light is arranged between a light feeding member and a light receiving element. CONSTITUTION:A filter 1 composed of photochromic glass of which the color is made dark and optical transmission factor is decreased as an amount of light is increased, is arranged in front of a light receiving element 4. With this arrangement, a combustion light incident from one end 31 of a light feeding member 3 is projected to the light receiving element 4 through the filter 1. At this time, although the combustion light is weak during a load operation of an engine, its transmission factor is high, so that it may be sufficiently detected with the light receiving element 4. In turn, under a high load operation, the mount of light is increased and at the same time a noise light of the remaining coal which is relatively low is generated. In this case, the transmission factor of the filter 1 is decreased and the noise light does not pass through the filter. Therefore, it is possible to prevent erroneous sending of light generated from the remaining coal. |
