Abstract: The present invention relates to methods and systems or apparatuses for analyzing fluids. More particularly the present invention relates to apparatuses and methods that employ impedance spectroscopy (IS) for analyzing fuels. Fuels of interest include biofuel, particularly biodiesel. Hand-held and “in-line” IS apparatuses are disclosed.

Abstract: The present invention relates to methods and systems or apparatuses for analyzing fluids. More particularly the present invention relates to apparatuses and methods that employ impedance spectroscopy (IS) for analyzing fuels. Fuels of interest include biofuel, particularly biodiesel. Hand-held and “in-line” IS apparatuses are disclosed.

Abstract: A system and method for monitoring and controlling the properties of fluids is disclosed. The inventive concept employs impedance spectroscopy (IS) measurements, and is suitable for real-time, in situ, monitoring and quality control operations, such as quality control during the manufacture of blended lubricants. IS data are obtained for three or more frequencies, where the lowest frequency is less than 1 Hz and the highest frequency is greater than 1 Hz. These data may be interpreted according to statistical techniques such as Principal Component Regression, analytical techniques such as equivalent circuit modeling, or by a combination thereof. The data analysis provides characteristics, or IS signatures, relating to the properties of the fluid. IS signatures for a test fluid are compared to IS signatures for calibration fluids to determine whether the properties of the test fluid fall within specified limits.

Abstract: Impedance spectroscopy is used to determine values associated with properties of a substance such as a fluid. In some embodiments, the present invention is applied to engine lubricants. A spectral matrix is constructed that comprises data taken from spectral plots. Also constructed is a result matrix comprising known quantities of a plurality of fluid constituents. A known analytic technique is performed on the spectral matrix to identify at least one principal component having significant influence on the spectral matrix. A reduced spectral matrix, wherein each column in the reduced spectral matrix is associated with a principal component having significant influence on the spectral matrix, is next created. A statistical technique uses the reduced spectral matrix and the result matrix to create at least one prediction equation. The prediction equation is used to predict at least one property in a second substance in situ.

Abstract: An impedance spectroscopy technique and system for detecting in real time engine coolant contamination in lubricant. A probe is disposed in the lubricant and the probe excited with an a.c. voltage frequency sweep over a selected frequency range. The current and current phase angle are measured at selected frequency intervals and the reactance and resistance computed and plotted at each frequency internal as Nyquist plots. The Nyquist minimum is determined at various lubricant temperatures and a database compiled. The probe is then excited in-situ and current measurements taken for a selected frequency lower than the Nyquist minimum to insure measurement of electrode surfaces characteristics. The reactance and resistance are then computed and the angle ? of change (slope) of reactance with respect to resistance computed. The value of ? is then compared with values of contamination concentration ? versus ? in a database, and the value of ? determined by interpolation.

Abstract: A system and method for monitoring and controlling the properties of fluids is disclosed. The inventive concept employs impedance spectroscopy (IS) measurements, and is suitable for real-time, in situ, monitoring and quality control operations, such as quality control during the manufacture of blended lubricants. IS data are obtained for three or more frequencies, where the lowest frequency is less than 1 Hz and the highest frequency is greater than 1 Hz. These data may be interpreted according to statistical techniques such as Principal Component Regression, analytical techniques such as equivalent circuit modeling, or by a combination thereof. The data analysis provides characteristics, or IS signatures, relating to the properties of the fluid. IS signatures for a test fluid are compared to IS signatures for calibration fluids to determine whether the properties of the test fluid fall within specified limits.

Abstract: Impedance spectroscopy is used to determine values associated with properties of a substance such as a fluid. In some embodiments, the present invention is applied to engine lubricants. A spectral matrix is constructed that comprises data taken from spectral plots. Also constructed is a result matrix comprising known quantities of a plurality of fluid constituents. A known analytic technique is performed on the spectral matrix to identify at least one principal component having significant influence on the spectral matrix. A reduced spectral matrix, wherein each column in the reduced spectral matrix is associated with a principal component having significant influence on the spectral matrix, is next created. A statistical technique uses the reduced spectral matrix and the result matrix to create at least one prediction equation. The prediction equation is used to predict at least one property in a second substance in situ.

Abstract: A probe having a pair of closely spaced electrodes is immersed in the lubricant and one electrode is excited with a relatively low voltage AC current. The frequency is swept over a range of about 1-10,000 Hertz and the current and phase angle measured at selected frequency intervals. The reactive (Z?) and resistive (Z?) impedances are computed for each current measurement and values of Z? plotted as a function of Z? as a Nyquist plot. The center of curvature of the plot between the origin and the minimum value of Z? is located; and, the angle of depression of a line from the origin through the center of curvature ? is determined from the plot. Samples of lubricant having known concentration of soot are measured and the angle ? determined for each sample. The angle is then plotted as a function of soot concentration and a smooth curve fitted to the data plots. The curve may be programmed into a microcomputer to be used with the sensor for real time determination of soot concentration.