Oil deterioration detector method and apparatus
First Claim
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1. An apparatus for detecting the degree of deterioration of lubricating oil used in an internal combustion engine, comprising:
- (a) an AC voltage source for generating an AC voltage of a predetermined frequency ranging from about 50 KHz to about 500 KHz;
(b) a sensor including a pair of spaced apart electrodes dipped into the lubricating oil while the oil is in the internal combustion engine, the electrodes and the oil between them forming a sensor capacitor having a capacity that varies as a function of the lubricating oil dielectric constant, circuit means for connecting said sensor capacitor to said AC voltage source and for generating an output having a value corresponding to the lubricating oil dielectric constant; and
(c) an indicator connected to be responsive to said output for indicating oil deterioration degree corresponding to the output of said sensor, said indicator being arranged to indicate that the oil deterioration degree is relatively low and high in response to the impedance between the electrodes being respectively relatively high and low, whereby the indicator response is independent of temperature of the oil for oil temperatures above a predetermined level corresponding with operation of the internal combustion engine.
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Abstract
The degree of deterioration of lubricating oil used in an internal combustion engine is detected by measuring the lubricating oil dielectric constant with a pair of spaced sensor capacitor electrodes in the lubricating oil. The sensor capacitor is connected to a fixed capacitor to form a voltage divider connected across a constant frequency AC voltage source so that a developed voltage across the sensor capacitor corresponds to the lubricating oil dielectric constant. The frequency of the AC voltage is set at a value ranging from 50 KHz to 500 KHz.
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Citations
13 Claims
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1. An apparatus for detecting the degree of deterioration of lubricating oil used in an internal combustion engine, comprising:
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(a) an AC voltage source for generating an AC voltage of a predetermined frequency ranging from about 50 KHz to about 500 KHz; (b) a sensor including a pair of spaced apart electrodes dipped into the lubricating oil while the oil is in the internal combustion engine, the electrodes and the oil between them forming a sensor capacitor having a capacity that varies as a function of the lubricating oil dielectric constant, circuit means for connecting said sensor capacitor to said AC voltage source and for generating an output having a value corresponding to the lubricating oil dielectric constant; and (c) an indicator connected to be responsive to said output for indicating oil deterioration degree corresponding to the output of said sensor, said indicator being arranged to indicate that the oil deterioration degree is relatively low and high in response to the impedance between the electrodes being respectively relatively high and low, whereby the indicator response is independent of temperature of the oil for oil temperatures above a predetermined level corresponding with operation of the internal combustion engine. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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- 8. A method of determining the degree of deterioration of lubricating oil in an operating internal combustion engine comprising the steps of measuring the capacitance of the oil by applying AC electric energy having a frequency of at least 50 KHz across a pair of electrodes in the oil while the engine is operating, and indicating that the measured oil has relatively low and high deterioration degrees in response to the measured capacitance being respectively relatively low and high, whereby the indication of the deterioration degree of the oil is independent of the oil temperature for oil temperatures above a predetermined level corresponding with operation of the internal combustion engine.
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12. A method of determining the degree of deterioration of lubricating oil in an operating internal combustion engine comprising the steps of measuring the impedance between a pair of capacitor electrodes in the oil while the engine is operating, indicating that the measured oil has relatively low and high deterioration degrees in response to the measured impedance being respectively relatively high and low, and inhibiting the indicating step while the oil temperature is less than 80°
- C. whereby the indication of the deterioration degree of the oil is independent of the oil temperature.
- View Dependent Claims (13)
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