Claims
- 1. A sensor useful for measuring methanol content within a mixture, comprising:
a capacitor having a first, generally cylindrical electrode and a second electrode at least partially surrounding the first electrode, the electrodes being spaced apart such that the mixture flows between the electrodes; a first oscillator that causes the capacitor to operate in a first mode to provide an indication of the capacitance of the capacitor when the mixture is between the electrodes; a second oscillator that causes the capacitor to operate in a second mode to provide an indication of the conductance of the capacitor when the mixture is between the electrodes; and a controller that switches between the first and second oscillators to obtain the respective indications.
- 2. The sensor of claim 1, including a single mechanical connection between the first and second oscillators and the capacitor, the controller selectively electrically operating the respective oscillators with the capacitor to obtain a desired one of the indications.
- 3. The sensor of claim 2, including electronic switches associated with each of the oscillators that are responsive to the controller to electrically operate the selected oscillator with the capacitor.
- 4. The sensor of claim 1, including a temperature sensor supported within the second electrode, the sensor providing an indication of the mixture temperature.
- 5. The sensor of claim 4, wherein the controller uses the temperature information, the capacitance indication and the conductance indication to determine the contents of the mixture.
- 6. The sensor of claim 5, including a memory portion having a plurality of predetermined values indicative of mixture content and wherein the controller determines the content from among the predetermined values based upon the temperature information, the capacitance indication and the conductance indication.
- 7. The sensor of claim 4, wherein the second electrode is hollow and including a spacer that supports the temperature sensor in a chosen position within the second electrode.
- 8. The sensor of claim 4, including a thermally conductive grease in a spacing between an inner surface of the second electrode and the temperature sensor and wherein the thermally conductive grease contacts the second electrode and the temperature sensor.
- 9. The sensor of claim 1, wherein the sensor provides an output wave form that has a period corresponding to the capacitance indication and timing information corresponding to the conductance indication.
- 10. The sensor of claim 9, wherein the timing information comprises a pulse width.
- 11. The sensor of claim 9, wherein the timing information comprises a duty cycle.
- 12. The sensor of claim 9, wherein the sensor output includes second timing information corresponding to a temperature indication obtained by a temperature sensor included in the sensor.
- 13. The sensor of claim 12, wherein the timing information corresponding to the conductance indication and the second timing information corresponding to the temperature indication are provided in alternating cycles of the wave form output.
- 14. The sensor of claim 1, wherein the first electrode comprises a hollow, generally cylindrical body with open ends and the second electrode comprises a generally cylindrical body having at least one end that is closed and including a sealing arrangement near one end of the electrodes for fluidly sealing a space between the first and second electrodes.
- 15. The sensor of claim 14, wherein the first electrode includes at least one opening in a sidewall of the electrode to allow fluid flow through one of the open ends of the first electrode, between the two electrodes and out of the sidewall opening.
- 16. The sensor of claim 1, including a sensor support portion that houses the controller and the oscillators such that the controller and the oscillators are fluidly isolated from the mixture that flows between the electrodes.
- 17. A method of determining a methanol content of a mixture, comprising the steps of:
providing a single capacitor having two electrodes between which the mixture flows; using the capacitor in a first mode to obtain an indication of the conductance of the capacitor with the mixture between the electrodes; using the capacitor in a second mode to obtain an indication of the capacitance of the capacitor with the mixture between the electrodes.
- 18. The method of claim 17, including electrically operating a first oscillator having a first frequency associated with the capacitor in the first mode and electrically operating a second oscillator having a second frequency associated with the capacitor in the second mode.
- 19. The method of claim 17, including determining a temperature of the mixture and using the determined temperature, the capacitance indication and the conductance indication to determine the methanol content of the mixture.
- 20. The method of claim 19, including providing a wave form sensor output that has a period corresponding to the capacitance indication, a first pulse width corresponding to the determined temperature and a second pulse width corresponding to the conductance indication.
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. Provisional Application Nos. 60/341,025 and 60/341,042, which were filed on Oct. 30, 2001. This application is a continuation-in-part of U.S. Ser. No. 10/150,903, which was filed on May 16, 2002, which claims priority to U.S. Provisional Application Nos. 60/291,781, which was filed on May 17, 2001; 60/325,369, which was filed on Sep. 27, 2001; and 60/341,042, which was filed on Oct. 30, 2001.
Provisional Applications (5)
|
Number |
Date |
Country |
|
60341025 |
Oct 2001 |
US |
|
60341022 |
Oct 2001 |
US |
|
60291781 |
May 2001 |
US |
|
60325369 |
Sep 2001 |
US |
|
60341022 |
Oct 2001 |
US |
Continuation in Parts (1)
|
Number |
Date |
Country |
Parent |
10150903 |
May 2002 |
US |
Child |
10284433 |
Oct 2002 |
US |