| 摘要 |
PURPOSE:To prevent an abnormal ignition caused by supplying fuel as well as air to a combustion part through an oil feeding device by a method wherein a light emitting of a light emitting element is detected by a light receiving element when a fuel level in an auxiliary tank is descended lower than a desired position of a liquid level gauge. CONSTITUTION:In case that a fuel level in an auxiliary tank 1 is raised higher than a position of a liquid level gauge to which a light emitting element 6 emits light and radiates, a emitted light A from the light emitting element 6 passes through the liquid level gauge 2 and runs directly in the fuel as shown by B, so that the light receiving element 7 does not receive any emitted light from the light emitting element 6. In case that the fuel level in the auxiliary tank 1 is descended lower than the position of the liquid level gauge 2 to which the light emitting element 6 emits light and radiates, the emitted light A from the light emitting element 6 is refracted as shown by C by the first prism surface 13 in the liquid level gauge 2, further refracted as shown by D by the second prism surface 14 and then the light is received by the light receiving element 7. |
