In-situ oil analyzer and methods of using same, particularly for continuous on-board analysis of diesel engine lubrication systems

An apparatus for monitoring the condition of flowing lubrication oil, the apparatus comprising:

• enclosure means for confining a volume of test subject lubricating oil;
• conduit means for supplying said enclosure means with a flow stream of lubricating oil;
• a sensor having at least two electrically conductive elements exposed to said oil at a boundary area respective to said enclosure means, said oil separating said conductive elements as an insulating dielectric medium therebetween to form a capacitor, said sensor being located within said enclosure means at a position for selective flushing of accumulated contaminants from said conductive elements by said oil flow stream;
• and
• monitor means for monitoring the capacitance of said sensor at discrete intervals so as to determine the condition of the subject lubricating oil based upon the change in sensor capacitance over said discrete time intervals.

An internal combustion engine having an engine oil circulation system, an electronic engine controller, and an engine oil analyzing system in communication with the engine controller, the engine oil analyzing system comprising:

• a housing attached to the engine and having a measurement chamber in fluid communication with the engine oil circulation system;
• a capacitive sensor disposed within said housing, said sensor characterized by at least two conductive elements having a space therebetween for accommodating engine oil which functions as a dielectric;
• control logic including memory in communication with said sensor for providing power to said sensor, measuring frequency response of said sensor, and analyzing changes in the frequency response of said sensor over time;
• and
• an electromagnet proximate said sensor for selectively creating a magnetic field within the measurement chamber, said electromagnet being controlled by said control logic.

An engine oil analyzing system for use with an internal combustion engine having an electronic engine controller, the engine including an engine oil circulation system having a port adapted to receive an engine oil filter, the engine oil analyzing system comprising:

• a generally cylindrical housing adapted to engage the port and establish fluid communication with the engine oil circulation system;
• a perforated annular sleeve disposed within said housing and concentric thereto;
• an annular filter element disposed about said annular sleeve within said housing;
• a generally annular baffle member disposed concentrically about said filter element within said housing so as to divert engine oil radially outward into an annular measurement chamber;
• and
• at least one capacitive sensor exposed to at least a portion of the annular measurement chamber, each of the at least one sensor including at least two conductive elements having a space therebetween for accommodating engine oil which functions as a dielectric.

An internal combustion engine having an engine oil circulation system, an electronic engine controller, and an engine oil analyzing system in communication with the engine controller, the engine oil analyzing system comprising:

• a housing attached to the engine and having a measurement chamber in fluid communication with the engine oil circulation system;
• a capacitive sensor disposed within said housing, said sensor characterized by at least two conductive elements having a space therebetween for accommodating engine oil which functions as a dielectric;
• and
• control logic including memory in communication with said sensor for providing power to said sensor, measuring frequency response of said sensor, and analyzing changes in the frequency response of said sensor over time.