Eaton Corporation

Victor E Shtaida

Lian Q Zou

James E Hansen

Richard Walter Hirthe

Sher Schachameyer

Birger Pahl

Peter J McGinnis

Edward Francis Buck

Charles J Koehler

Anne Matthews Brunson

A tubular probe having annularly spaced electrodes is immersed in ATF and sequentially excited with an alternating voltage at a relatively high and low frequency. The current is measured at both frequencies and the difference in impedance computed; and, the differential impedance is corrected for temperature and the corresponding value of one of TAN per ASTM D-669, Delta Oxidation per ASTME-168 (&#x394;OX) and HPDSC induction time per ASTM D-5483 (MIN) determined from a lookup table of values of TAN, &#x394;OX and MIN versus impedance differential for known fluid conditions. The remaining useful life (RUL) may then be computed from determined present value of TAN, &#x394;OX or MIN. When the temperature corrected impedance difference &#x394;Zreaches 6.5&#xd7;10Ohms, the ATF is considered to have reached the end of its useful life.

Monitoring automatic transmission fluid condition in real time

A probe having a pair of electrodes is excited with a low A.C. voltage at a relatively high and relatively low frequency and the difference in current measured. The difference dZ between bulk fluid and interfacial impedance is computed from the current difference. The rate of change &#x394;dZ of the impedance difference is determined over a time interval and a physiochemical parameter (X) determined when &#x394;dZ is positive from lubricant with known amounts of constituents selected from the group consisting of (a) Phosphorus, Oxygen and Carbon (P&#x2014;O&#x2014;C); (b) Phosphorous and double bond Sulphur (P&#x2550;S); (c) Zincdialkyldithiophosphate (ZDDP); and (d) the Total Base Number TBN by measuring CaCO(CO3), from a table of the selected parameter X versus dZ in a first region of the table and determining RUL from a table of RUL versus parameter X (X). The value of the selected parameter X when &#x394;dz is negative is determined from a second region of the table of X versus dZ. The rate of change &#x3a8; of X over a time interval is determined and RUL determined from a known value of Xfor the end of the lubricant life.

Method of determining the fluid condition of diesel engine lubricant during real time operation

A probe assembly for use in monitoring fluid conditions in real time in a transducer utilizing impedance spectroscopy and having two closely spaced tubular concentric electrodes. The electrodes have a surface area of about 8.1 to 10.8 cm spaced in the range of about 0.1 to 0.55 mm. In one embodiment a concentric outer tubular Faraday shield is employed for monitoring fluid in a non-metallic vessel. The probe assembly is particularly suitable for monitoring hydraulic fluid including automatic transmission fluid and mineral based engine oil for diesel and gasoline engines.

Probe assembly for a fluid condition monitor and method of making same

A combination fluid condition monitor and fluid level sensor having an excitation electrode divided into two segments disposed closely spaced and parallel to current sensing electrode. For the fluid condition monitoring mode function both segments of the excitation electrode are commonly excited sequentially at high and low frequencies and the currents sensed in the sensing electrode employed to compute the difference in impedance for determining the fluid condition. For the level sensing mode function a mode switching circuit grounds one of the excitation electrode segments and excites the other then grounds the other segment and excites the one segment and the resultant currents ratioed to determine the amount of electrode immersed in fluid and hence the fluid level.

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Franklin, WI, United States of America

Victor E Shtaida