SOOT DETECTOR FOR ENGINE OIL
First Claim
1. A method for detecting a concentration of soot particles in engine oil comprising the steps of:
- applying a microwave signal having a frequency to one end of a transmission line having a probe tip at a second end of the transmission line and varying the frequency of the microwave signal within a range of frequencies, the probe tip being exposed to the engine oil;
detecting a probe voltage at a stationary detection point along an axial length of the transmission line for selected frequencies within the range of frequencies;
determining a probe frequency of the selected frequencies when the probe voltage is equal to a null voltage of a standing wave within the transmission line;
comparing the probe frequency to a probe reference frequency, wherein the probe reference frequency is a frequency of the microwave signal when the probe voltage is equal to a null voltage for a known concentration of soot particles in the engine oil; and
calculating the concentration of soot particles in the engine oil based upon a result of the comparing step.
1 Assignment
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Accused Products
Abstract
A method and apparatus for detecting the concentration of soot particles in engine oil. A microwave signal having a varying frequency is applied to a transmission line having a probe tip exposed to the engine oil. A voltage is read at a stationary detection point along the length of the transmission line for each applied frequency. The applied frequency when the probe voltage is equal to a null voltage of a standing wave within the transmission line is compared to a reference frequency determined when the probe voltage is equal to a null voltage for a known concentration of soot particles. The concentration is calculated based upon the result of the comparison. Preferably, a reference probe receives the same input signal. A known relationship between the reference probe and the transmission line is then used to eliminate temperature effects on the applied frequency.
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Citations
31 Claims
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1. A method for detecting a concentration of soot particles in engine oil comprising the steps of:
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applying a microwave signal having a frequency to one end of a transmission line having a probe tip at a second end of the transmission line and varying the frequency of the microwave signal within a range of frequencies, the probe tip being exposed to the engine oil;
detecting a probe voltage at a stationary detection point along an axial length of the transmission line for selected frequencies within the range of frequencies;
determining a probe frequency of the selected frequencies when the probe voltage is equal to a null voltage of a standing wave within the transmission line;
comparing the probe frequency to a probe reference frequency, wherein the probe reference frequency is a frequency of the microwave signal when the probe voltage is equal to a null voltage for a known concentration of soot particles in the engine oil; and
calculating the concentration of soot particles in the engine oil based upon a result of the comparing step. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. An apparatus for detecting a concentration of soot particles in engine oil comprising:
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means for applying a microwave signal having a frequency to one end of a transmission line having a probe tip at a second end of the transmission line and for varying the frequency within a range of frequencies, the probe tip being exposed to the engine oil;
means for detecting a probe voltage at a stationary detection point along an axial length of the transmission line for selected frequencies within the range of frequencies;
means for determining a probe frequency of the selected frequencies when the probe voltage is equal to a null voltage of a standing wave within the transmission line;
means for comparing the probe frequency to a probe reference frequency, wherein the probe reference frequency is a frequency of the microwave signal when the probe voltage is equal to a null voltage for a known concentration of soot particles in the engine oil; and
means for calculating the concentration of soot particles in the engine oil based upon a result of the comparing step. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29, 30, 31)
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Specification