OIL MIST DETECTOR

摘要

An oil mist detector is provided to judge that the transparent window is contaminated based on the comparison result so that the contamination of the transparent window is detected accurately by comparing a contamination error value with a detection signal value generated from a light receiving device. An oil mist detector(1) comprises a casing(6) having an oil mist introduction chamber arranged in a crankcase of an internal combustion engine. A light emitting device and a light receiving device so arranged as to face an outer side of a transparent window provided in the oil mist introduction chamber. The light emitting device emits light to a predetermined detection region in the oil mist introduction chamber through the transparent window, and the light receiving device receives through the transparent window scattering light generated from the irradiated light hitting oil mist present in the detection region, thereby achieving oil mist detection. A zero point shifting structure is provided which makes a given amount of background scattering light from the casing incident on the light receiving device under absence of oil mist in the oil mist introduction chamber. A control device(12) receives a detection signal from the light emitting device. The control device has a contamination error judging part for comparing a contamination error value with a detection signal value, and judges that the transparent window is contaminated when the detection signal value exceeds the contamination error value.