| 摘要 |
PURPOSE:To maintain detecting accuracy, and also to detect detecting impossibility by correcting the result of detection of a smoke density based on the result of detection of the smoke density in case when supply of fuel to an engine has been stopped. CONSTITUTION:The light emitted by a light emitting element 38 of a projecting part 37 transmits through the inside of an exhaust passage 23a, is made incident on a photodetector 41, and a detecting signal VA corresponding to a smoke density in the course of exhaust is outputted from a detecting circuit 50. Compressed air from an air pump 44 is led into hollow tubes 39, 42, and adhesion of smoke to the light emitting element 38 and the photodetector 41 is prevented. On the other hand, a discriminating circuit 52 outputs a discriminating signal SB when a supply stop signal SA is inputted continuously for a prescribed time from a fuel supply stop detecting circuit 51, and an output holding circuit 53 holds the detecting signal VA. Also, a calibrating circuit 54 detects a variation quantity with respect to an initial value of a reference signal VB, calibrates the detecting signal VA in accordance with the result of this calculation, and outputs it as a smoke detecting signal VC. |
