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Oil deterioration detector method and apparatus

  • US 4,646,070 A
  • Filed: 11/12/1982
  • Issued: 02/24/1987
  • Est. Priority Date: 11/17/1981
  • Status: Expired due to Fees
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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