Abstract: A method and a device for detecting a deterioration of vehicle oil are disclosed in which the end point of the oil service life can be detected with higher accuracy, while at the same time detecting the progress of the oil condition in the vicinity of the end point of the oil service life. The acidity or basicity of the vehicle oil is measured using a pH sensor (11) generating an output in responding to the degree of the acidity or basicity. The deterioration of the vehicle oil can be detected based on the fact that with the increase in vehicle mileage, a line approximating the output of the pH sensor (11) with respect to the vehicle mileage has a tendency to change from a first inclination to a second inclination larger than the first inclination and then from the second inclination to a third inclination smaller than the second inclination.

Abstract: An oil condition sensor detects a condition of oil in response to the potential difference between electrodes. The electrodes include at least a first and second electrodes coaxially arranged. The electrodes have projections being arranged to face each other in an opposed manner. Therefore, the projections provide wide surface area that performs as electrodes. It is possible to provide compact oil condition sensor that is easy to install into an oil tank or oil pan.

Abstract: A method and a device for detecting a deterioration of vehicle oil are disclosed in which the end point of the oil service life can be detected with higher accuracy, while at the same time detecting the progress of the oil condition in the vicinity of the end point of the oil service life. The acidity or basicity of the vehicle oil is measured using a pH sensor (11) generating an output in responding to the degree of the acidity or basicity. The deterioration of the vehicle oil can be detected based on the fact that with the increase in vehicle mileage, a line approximating the output of the pH sensor (11) with respect to the vehicle mileage has a tendency to change from a first inclination to a second inclination larger than the first inclination and then from the second inclination to a third inclination smaller than the second inclination.

Abstract: In a pair of electrodes where a potential difference is changed in accordance with acidity or basicity of oil, a reference electrode is made of cobalt or a cobalt alloy, and a sensitive electrode is made of tungsten or a tungsten alloy. The sensitive electrode is used in combination with the reference electrode. Accordingly, it is possible to provide a pair of electrodes for detecting the acidity or the basicity of the oil which use a novel electrode material not hazardous to the environment and at the same time, suited for use in a semiconductor fabrication technique.

Abstract: An oil condition sensor detects a condition of oil in response to the potential difference between electrodes. The electrodes include at least a first and second electrodes coaxially arranged. The electrodes have projections being arranged to face each other in an opposed manner. Therefore, the projections provide wide surface area that performs as electrodes. It is possible to provide compact oil condition sensor that is easy to install into an oil tank or oil pan.

Abstract: In a pair of electrodes where a potential difference is changed in accordance with acidity or basicity of oil, a reference electrode is made of cobalt or a cobalt alloy, and a sensitive electrode is made of tungsten or a tungsten alloy. The sensitive electrode is used in combination with the reference electrode. Accordingly, it is possible to provide a pair of electrodes for detecting the acidity or the basicity of the oil which use a novel electrode material not hazardous to the environment and at the same time, suited for use in a semiconductor fabrication technique.

Abstract: An apparatus for detecting the concentration of particles in a liquid includes a light-emitting portion for emitting examination light which is totally reflected-by a boundary surface contiguous to the liquid to be examined, a photosensor for receiving the totally-reflected light, a reference sensor for directly receiving the examination light, and a judgment portion for finding the reflectance from outputs of the two sensors to compute the particle concentration. In case that the liquid to be examined is lubricating oil of an engine, the concentration of carbon particles is calculated, thereby judging the deterioration of the lubricating oil.

Abstract: An oil deterioration detector comprising a sensitive electrode whose electric potential varies in response to acidity and/or basicity of oil to be measured, and a reference electrode associated with this sensitive electrode. An electrically conductive housing accommodates the sensitive electrode and the reference electrode together with the oil. A potential difference detector detects oil deterioration by measuring a potential difference between the sensitive electrode and the reference electrode. And, an insulating member is interposed between these electrodes and the electrically conductive housing for electrically insulating these electrodes from the electrically conductive housing. The reference electrode is grounded together with the electrically conductive housing. An insulating, hydrophilic porous member would be interposed between the sensitive electrode and the reference electrode.