Machine fluid sensor

• US 20060218996A1
• Filed: 05/12/2006
• Published: 10/05/2006
• Est. Priority Date: 10/18/2002
• Status: Active Grant

• Current Assignee: Meas France
• Original Assignee: Symyx Technologies Incorporated (Dassault Systemes SA)
• Inventors: Padowitz, Dave, Bennett, James, Spitkovsky, Mikhail, Pinkas, Daniel M., Varni, John F., Dales, G. Cameron, Matsiev, Leonid, Kolosov, Oleg, Guan, Shenheng, Low, Eric, Gammer, Vladimir, Uhrich, Mark, Walker, Blake
• Granted Patent: US 7,254,990 B2
• Time in Patent Office: Days
• US Class Current: 73/64.530
• CPC Class Codes: F02D 2200/0611 Fuel type, fuel composition or fuel quality
• CPC Class Codes: F02D 2250/11 Oil dilution, i.e. prevention thereof or special controls according thereto
• CPC Class Codes: F02D 41/021 Introducing corrections for particular conditions exterior to the engine conjoint control of vehicle sub-units for propelling the vehicle B60W30/18
• CPC Class Codes: G01F 23/2966 making use of acoustical resonance or standing waves
• CPC Class Codes: G01N 11/16 by measuring damping effect upon oscillatory body
• CPC Class Codes: G01N 2291/014 Resonance or resonant frequency
• CPC Class Codes: G01N 2291/0226 Oils, e.g. engine oils
• CPC Class Codes: G01N 2291/02416 Solids in liquids
• CPC Class Codes: G01N 2291/02818 Density, viscosity
• CPC Class Codes: G01N 2291/02836 Flow rate, liquid level
• CPC Class Codes: G01N 2291/0422 Shear waves, transverse waves, horizontally polarised waves
• CPC Class Codes: G01N 2291/0423 Surface waves, e.g. Rayleigh waves, Love waves
• CPC Class Codes: G01N 2291/0426 Bulk waves, e.g. quartz crystal microbalance, torsional waves
• CPC Class Codes: G01N 2291/0427 Flexural waves, plate waves, e.g. Lamb waves, tuning fork, cantilever
• CPC Class Codes: G01N 29/022 Fluid sensors based on microsensors, e.g. quartz crystal-microbalance [QCM], surface acoustic wave [SAW] devices, tuning forks, cantilevers, flexural plate wave [FPW] devices microdevices per se B81B
• CPC Class Codes: G01N 29/036 by measuring frequency or resonance of acoustic waves
• CPC Class Codes: G01N 29/30 Arrangements for calibrating or comparing, e.g. with standard objects
• CPC Class Codes: G01N 29/348 with frequency characteristics, e.g. single frequency signals, chirp signals measuring frequency of mechanical vibrations or acoustic waves in general G01H1/06, G01H3/04; measuring frequency or analysing frequency spectra G01R23/00
• CPC Class Codes: G01N 9/002 using variation of the resonant frequency of an element vibrating in contact with the material submitted to analysis G01N9/34 takes precedence

Abstract

A sensor for sensing one or more properties of a vehicle fluid has a tuning fork resonator adapted to contact the fluid. The tuning fork resonator comprises two tines and is operable to oscillate so that the two tines move in opposite phase at a frequency of less than 1 MHz while contacting the fluid to generate a resonator response indicative of one or more properties of the fluid. In another aspect, a sensor includes a substrate and a flexural resonator on the substrate and adapted to contact the fluid. Circuitry for operation of the resonator is on the substrate. The resonator is adapted to receive an input signal and to oscillate while contacting the fluid to generate a resonator response indicative of one or more properties of the fluid. One suitable application for the invention is monitoring the condition of a vehicle engine oil.

Claims

1. A fluid sensor for sensing one or more properties of a fluid in a vehicle, said sensor comprising:

a tuning fork resonator adapted to contact said fluid when the sensor is mounted on the vehicle,

said tuning fork resonator comprising two tines and being operable when mounted on said vehicle to receive an input signal and to oscillate so that the two tines move in opposite phase at a frequency of less than 1 MHz while in contact with said fluid to generate a resonator response indicative of said one or more properties of said fluid.

2. The fluid sensor of claim 1 wherein the tuning fork resonator comprises a base and tines of a piezoelectric or crystalline material.

3. The fluid sensor of claim 2 further comprising a plurality of electrodes, each of the tines having at least one electrode attached thereto.

4. The fluid sensor of claim 3 wherein the two tines each comprise four faces, each of the faces having an electrode attached thereto.

5. The fluid sensor of claim 1 wherein the tuning fork resonator is coated over at least a portion of its surface.

6. The fluid sensor of claim 5 wherein said vehicle fluid is engine oil, and wherein the tuning fork resonator is coated with a material resistant to corrosion from the engine oil or to the build-up of contaminants present in the engine oil.

7. The fluid sensor of claim 5 wherein the tuning fork resonator is coated with a hydrophobic material.

8. The fluid sensor of claim 1 further comprising at least one connector for connecting the tuning fork resonator with a source of said input signal on board said vehicle.

9. The fluid sensor of claim 8 wherein said at least one connector is configured for connecting said tuning fork resonator to a processor on board said vehicle for processing said response of the tuning fork resonator to measure said one or more properties of said fluid.

10. The fluid sensor of claim 1 further comprising a holder for holding said tuning fork resonator in a position for contact with said vehicle fluid, said holder being configured for attachment to said vehicle.

11. The fluid sensor of claim 1 further comprising a housing for housing said tuning fork resonator, said housing being configured for attachment to said vehicle and having one or more openings for allowing said vehicle fluid to pass therethrough.

12. The fluid sensor of claim 1 wherein said tuning fork resonator is mounted on a surface mountable substrate, and wherein said sensor further comprises circuitry on said substrate.

13. The fluid sensor of claim 11 wherein said surface mountable substrate is a computer chip.

14. The fluid sensor of claim 1 wherein said one or more fluid properties includes at least the density of the fluid and the viscosity of the fluid independent of the density.

15. The fluid sensor of claim 1 wherein the tuning fork resonator comprises one or more layers deposited on a wafer shaped to form said tuning fork resonator.

16. The fluid sensor of claim 1 wherein the tuning fork resonator is mounted on said vehicle.

17. A fluid sensor for sensing one or more properties of a fluid in a vehicle, said sensor comprising:

a substrate,

a flexural resonator on the substrate adapted to contact said fluid when the substrate and sensor are mounted on the vehicle, and

circuitry on the substrate for operation of the resonator,

said resonator being adapted to receive an input signal and to oscillate while in contact with said fluid to generate a resonator response indicative of said one or more properties of said fluid.

18. The fluid sensor of claim 17 wherein the flexural resonator is a tuning fork resonator.

19. The fluid sensor of claim 18 wherein the tuning fork resonator comprises a base and tines of a piezoelectric or crystalline material.

20. The fluid sensor of claim 17 wherein the flexural resonator is coated over at least a portion of its surface.

21. The fluid sensor of claim 20 wherein said vehicle fluid is engine oil, and wherein the flexural resonator is coated with a material resistant to corrosion from the engine oil or to the build-up of contaminants present in the engine oil.

22. The fluid sensor of claim 17 further comprising at least one connector for connecting the flexural resonator with a source of said input signal on board said vehicle.

23. The fluid sensor of claim 17 wherein said substrate is a computer chip.

24. The fluid sensor of claim 17 wherein said one or more fluid properties includes at least the density of the fluid and the viscosity of the fluid independent of the density.

25. The fluid sensor of claim 21 wherein the substrate is mounted on said vehicle.