Machine Fluid Sensor

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.

1 . In combination with an engine control unit for controlling operation of an engine in a vehicle, 
 a fluid sensor for sensing one or more properties of a fluid in the vehicle,    said sensor comprising a tuning fork resonator for contacting said fluid when the sensor is mounted on the vehicle, said tuning fork resonator comprising two tines and being operable when mounted on the vehicle to receive an input signal and to oscillate so the two tines move in opposite phase at a frequency of less than about 1 MHz while in contact with said fluid to generate a resonator response indicative of said one or more properties of said fluid, and    wherein the engine control unit is operable to alter operation of the engine in response to said resonator response.    
   
   
       2 . The combination set forth in  claim 1 , wherein the fluid is engine oil and/or fuel.  
   
   
       3 . The combination set forth in  claim 1 , wherein said one or more properties of said fluid include at least the density of the fluid and the viscosity of the fluid independent of the density.  
   
   
       4 . The combination set forth in  claim 3 , wherein said one or more properties of said fluid further comprise an electrical property of said fluid.  
   
   
       5 . The combination set forth in  claim 1 , wherein the engine control unit is operable to alter at least one of air intake and timing of the engine in response to said resonator response.  
   
   
       6 . The combination set forth in  claim 1 , further comprising an environment conditioner operable to at least one of monitor and control the temperature of the environment proximate to the sensor.  
   
   
       7 . A method of controlling operation of an engine in a vehicle, the method comprising 
 contacting a fluid in the vehicle with a tuning fork resonator comprising two tines,    using an input signal to oscillate the tines so they move in opposite phase at a frequency of less than about 1 MHz while the tines contact the fluid to generate a resonator response indicative of one or more properties of said fluid, and    using an engine control unit to alter operation of the engine in response to said resonator response.    
   
   
       8 . A method as set forth in  claim 7 , wherein the contacting of said fluid with the tuning fork resonator comprising contacting fuel and/or oil.  
   
   
       9 . A method as set forth in  claim 7 , further comprising using the resonator response to determine at least the density of said fluid and the viscosity of said fluid independent of the density.  
   
   
       10 . A method as set forth in  claim 9 , further comprising using the resonator response to determine an electrical property of said fluid.  
   
   
       11 . A method as set forth in  claim 10 , wherein using said engine control unit to alter operation of the engine comprises using the engine control unit to alter at least one of air intake and timing of the engine.  
   
   
       12 . A method as set forth in  claim 11 , further comprising at least one of monitoring and controlling an environment proximate to the tuning fork resonator to a predetermined condition.  
   
   
       13 . A fluid sensor for sensing one or more properties of a fluid in a vehicle, said sensor comprising: 
 a housing;    a tuning fork resonator in the housing for contacting 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 the two tines move in opposite phase at a frequency of less than about 1 MHz while in contact with the fluid to generate a resonator response indicative of said one or more properties of said fluid; and    one or more additional sensing elements in the housing,    said housing having one or more openings to allow passage of said fluid through the housing.    
   
   
       14 . A fluid sensor for sensing one or more properties of a fluid in a vehicle, said sensor comprising: 
 a tuning fork resonator for contacting 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 the two tines move in opposite phase at a frequency of less than about 1 MHz while in contact with the fluid to generate a resonator response indicative of said one or more properties of said fluid; and    an environment conditioner operable to at least one of monitor and control the temperature of the environment proximate to the sensor.    
   
   
       15 . A fluid sensor as set forth in  claim 14  wherein the environment conditioner comprises a fluid temperature sensor for monitoring a temperature of said fluid proximate the tuning fork resonator.  
   
   
       16 . A fluid sensor as set forth in  claim 14  wherein the environment conditioner is operable to control the environment proximate the tuning fork to a predetermined condition.  
   
   
       17 . A fluid sensor as set forth in  claim 15  wherein the predetermined condition is a predetermined temperature range.  
   
   
       18 . A fluid sensor for sensing one or more properties of a fluid in a machine, said sensor comprising: 
 a tuning fork resonator for contacting said fluid when the sensor is mounted on the machine, said tuning fork resonator comprising two tines and being operable when mounted on said machine to receive an input signal and to oscillate so the two tines move in opposite phase at a frequency of less than about 1 MHz while in contact with the fluid to generate a resonator response indicative of said one or more properties of said fluid.    
   
   
       19 . A fluid sensor for sensing one or more properties of a fluid in a vehicle, said sensor comprising: 
 a tuning fork resonator for contacting said fluid when the sensor is mounted on the vehicle; and    a holder for holding the tuning fork resonator, the holder being configured for attaching the sensor to a surface of the vehicle such that the tuning fork resonator is exposed to fluid in a passage of 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 the two tines move in opposite phase at a frequency of less than about 1 MHz while in contact with the fluid to generate a resonator response indicative of said one or more properties of said fluid.