Kavlico Corporation

Sensata Technologies, Inc.

Custom Sensors & Technologies, Inc.

Marcos A Nassar

Kyong M Park

Nhan Nguyen

Mark L Urban

Gary L Casey

William Dale Cornwell

Scott McDaniel

Phuoc Vinh Le

Ernest W Cordan

Cliff C Sun

William D Cornwell

A differential capacitive pressure sensor of an embodiment of the present invention has first and second diaphragms positioned on opposing sides of a single substrate. Each diaphragm of the pressure transducer is configured to be exposed to a transient fluid, with the first and second pressure transducers being arranged with their respective deflection surfaces directed outwardly from each other. The differential capacitive pressure sensor may be configured to output representations of differential and common mode pressure of the transient fluids, where a representation of a common mode is cancelled in generating the representation of the differential pressure. The transient fluids may be the same fluid at different locations within a flow path. The diaphragms may be constructed from a ceramic material to be able to withstand exposure to corrosive or caustic fluids.

Differential pressure sensor with dual output using a double-sided capacitive sensing element

A capacitive pressure transducer of an embodiment of the present invention capacitively couples two electrodes on a substrate with a diaphragm electrode to form a transducing circuit without the need for a physical connection between the electrodes. Embodiments of the present invention have a substrate with a coupling electrode and a sensing electrode and an attached diaphragm with a diaphragm electrode. A spacer positioned between the substrate and the diaphragm provides for a cavity that defines a gap between the sensing electrode and the diaphragm electrode. A dielectric spacer may be positioned over the coupling electrode to increase the capacitance between the coupling electrode and the diaphragm electrode. The capacitive pressure transducer has similar electrical characteristics as existing capacitive pressure transducers, is easier to manufacture, and has long-term reliability and durability improvements brought about by the elimination of mechanical interconnects and additional conductive materials.

Pressure transducer with capacitively coupled source electrode

Described herein is the sense element assembly for a capacitive pressure sensor and method for creating same that has increased sensitivity without additional size. The sense element assembly and method includes fabricating an off-centered elliptically shaped center electrode, at least one elliptical annular-like electrode around the center electrode, a ground electrode and a method for fusing the layers together to optimize sensitivity.

Sensor element assembly and method

A preformed sensor housing including a conduit having an inside; a plug disposed within the conduit; and a deposit covering a portion of the plug and a portion of the conduit. A method is also disclosed for creating a thin film diaphragm on a housing including the step of inserting a sacrificial element into the housing; depositing a diaphragm material onto the sacrificial element and the housing; and removing the sacrificial element.

Preformed sensor housings and methods to produce thin metal diaphragms

A corrosion proof pressure transducer for measuring exhaust gas pressure includes a chip with a semiconductive diaphragm, electronics, and conductive pads thereon; with leads sonically bonded to the pads. To preclude degradation of the transducer by internal combustion engine exhaust gases, the chip may have (1) a thin glass passivation layer, (2) a vacuum deposited polymeric coating and (3) a layer of gel, thereon.

Corrosion-proof pressure transducer

A combined oil quality and fuel contamination sensing system includes a capacitive dielectric sensor and pressure sensing arrangements for measuring the dielectric constant of the oil and the pressure of the oil, respectively, with the oil pressure being indicative of oil viscosity and contamination. The sensors take measurements as oil flows through an internal combustion engine and provide an indication of the cause of a problem with oil in an engine. The system may also include a microcomputer and circuitry for generating an indication of dielectric constant and circuitry for generating an indication of the presence of contaminants within the engine. The system may also include an additional sensor measuring the temperature of oil within the system to adjust oil dielectric constant and viscosity indications. The capacitive dielectric sensor constitute the principal restriction in the flow path between an input high pressure sensing port and an outlet low pressure port.

Combined oil quality and viscosity sensing system

A combined mechanical linkage and force-measuring assembly includes a central capacitive force sensor, in which force applied to the sensor causes the flexing of a diaphragm toward and away from a substrate, and a change in the capacitance between two conductive surfaces on the diaphragm and the substrate is sensed and processed to indicate the direction and magnitude of the force applied to the linkage. The linkage may have two parts coupled together by a flange which flexes under applied forces, to change the spacing of the conductive surfaces.

Linkage with capacitive force sensor assembly

A sensor assembly for measuring characteristics of motor oil in a vehicle includes a housing adapted to be mechanically coupled to a vehicle for receiving motor oil of the vehicle and at least one capacitive sensor including sensing electrodes positioned relative to the housing to measure characteristics of motor oil between the sensing electrodes. The sensing electrodes are coated with a soot build-up inhibiting coating which, in a preferred embodiment, is a silicone coating. The at least one capacitive sensor include an oil level sensor and an oil deterioration sensor in a preferred embodiment.

Capacitive sensor assembly with soot build-up inhibiting coating

A sensor assembly includes a tilt sensor, an oil level sensor, an oil temperature sensor and an oil deterioration sensor, as well as associated output signal conditioning electronics integrated within a common assembly. The sensor assembly is configured to receive a volume of motor oil proportional to a total volume of oil in an engine. The oil level sensor, oil temperature sensor and oil deterioration sensors include electrodes which are completely or partially immersed in the volume of motor oil depending upon the total volume of oil in the engine. The tilt sensor includes only two electrodes both of which are at least partially immersed within a controlled volume of dielectric fluid which is physically and electrically isolated from the volume of motor oil. One of the electrodes of the tilt sensor is completely immersed in the controlled volume of dielectric fluid independent of an angle of the tilt sensor relative to a vector representing forces such as gravity applied to the tilt sensor.

Capacitive sensor assembly

An oil deterioration and contamination sensor includes a housing, a substrate with a first capacitive plate mounted within the housing, a second capacitive plate mounted to the housing close to the first capacitive plate, and a total reference capacitor which includes an external fixed reference capacitor. The second capacitive plate is mounted to the housing such that at least one fluid including oil freely circulates within a gap between the first and second capacitive plates thereby defining an oil deterioration and contamination sensor capacitor. The respective capacitances of the oil deterioration and contamination capacitor and the total reference capacitor provide an indication of a dielectric constant of the at least one fluid including oil within the gap. The sensor also includes circuitry for generating the indication of a dielectric constant and oil contamination detection circuitry adapted to receive and process the indication of a dielectric constant and to generate an indication of oil contamination when a dielectric constant of the at least one fluid including oil exceeds a predetermined value or exceeds a predetermined value at a rate of dielectric constant change in excess of a maximum ordinary rate of oil dielectric constant change.

Capacitive oil deterioration and contamination sensor

An oil deterioration sensor includes a housing, a substrate with a first capacitive plate mounted within the housing, a second capacitive plate mounted to the housing close to the first capacitive plate, and a total reference capacitor which includes an external fixed reference capacitor. The second capacitive plate is mounted to the housing such that oil freely circulates within a gap between the first and second capacitive plates thereby defining an oil deterioration sensor capacitor. The respective capacitances of the oil deterioration capacitor and the total reference capacitor provide an engine oil deterioration indication for the oil within the gap. The first capacitive plate is divided into a major sensing area, and a minor sensing area covering a relatively small portion of the total area of the first capacitive plate. The major sensing area and the second capacitive plate form the oil deterioration sensor capacitor. The total reference capacitor further includes an oil deterioration reference capacitor defined by the minor reference area and the second capacitive plate. The oil deterioration sensor further includes a temperature sensitive resistive element thermally connected to the substrate for providing a temperature adjustment to the engine oil deterioration indication, and circuitry utilizing the respective capacitances of the oil deterioration sensor capacitor and the total reference capacitor to generate the engine oil deterioration indication.

Oil deterioration sensor

An optical fiber position sensor utilizes a passive gray code encoded sensor head gray code for improved reliability. Optical energy is propagated to the sensor head over a plurality of optical fibers. At the sensor head, the optical energy is either reflected back along the same fiber or absorbed by the sensor head. The presence or absence of reflected optical energy on each fiber determine each bit state for a digital word. The sensor head is attached to a device to be monitored. Movement of the device causes translatory displacement of the sensor head relative to the fibers, thereby changing at least one bit state.

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Los Angeles, CA, United States of America

Marcos A Nassar