Device and method for detecting oil deterioration
First Claim
1. A method of detecting a deterioration of vehicle oil, said method comprising steps of:
- measuring an acidity or basicity of the vehicle oil using a pH sensor generating an output in response to the degree of the acidity or basicity of the vehicle oil;
monitoring a change in a change rate of the output from said pH sensor with one of an increasing driving mileage or driving time of a vehicle;
detecting the fact that the output from said pH sensor, after changing from a changing at a first change rate to a changing at a second change rate greater than said first change rate, changes from the changing at said second change rate to a changing at a third change rate smaller than said second change rate; and
judging that the service life of the vehicle oil has expired when the output from said pH sensor changes at said third change rate to detect the deterioration of the vehicle oil.
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Accused Products
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.
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Citations
16 Claims
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1. A method of detecting a deterioration of vehicle oil, said method comprising steps of:
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measuring an acidity or basicity of the vehicle oil using a pH sensor generating an output in response to the degree of the acidity or basicity of the vehicle oil;
monitoring a change in a change rate of the output from said pH sensor with one of an increasing driving mileage or driving time of a vehicle;
detecting the fact that the output from said pH sensor, after changing from a changing at a first change rate to a changing at a second change rate greater than said first change rate, changes from the changing at said second change rate to a changing at a third change rate smaller than said second change rate; and
judging that the service life of the vehicle oil has expired when the output from said pH sensor changes at said third change rate to detect the deterioration of the vehicle oil. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 10)
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9. A method of detecting a deterioration of vehicle oil, said method comprising steps of:
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measuring an acidity or basicity of the vehicle oil using a pH sensor generating an output in response to the degree of the acidity or basicity of the vehicle oil;
defining a plane with one of a driving mileage or driving time of the vehicle as one axis and the output from said pH sensor as the other axis perpendicular to said one axis;
using a vector on said plane starting from a point on a coordinate having a driving mileage or driving time x0 and a corresponding output V0 from said pH sensor and ending at a point on a coordinate having a driving mileage or driving time x1 greater than x0 and a corresponding output V1 from said pH sensor;
monitoring a change in a change rate of the output from said pH sensor; and
judging the deterioration of the vehicle oil, based on the fact that the inclination of said vector changes with the increasing driving mileage or driving time.
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11. A device for detecting a deterioration of a vehicle oil, said device comprising:
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a pH sensor mounted on an oil pan of said vehicle for generating an output in response to the degree of the acidity or basicity of the vehicle oil; and
means connected to said pH sensor for judging the deterioration of the vehicle oil, based on a driving mileage input to said pH sensor and the corresponding output from said pH sensor;
wherein said judging means detects the fact that the output from said pH sensor, after changing from a changing at a first change rate to a changing at a second change rate greater than said first change rate, changes from the changing at said second change rate to a changing at a third change rate smaller than said second change rate, and judges that the service life of the vehicle oil has expired when the output from said pH sensor comes to change at said third change rate. - View Dependent Claims (12, 13, 14, 15, 16)
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Specification