Use of optical spectrometry to evaluate the condition of used motor oil
US5194910A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 31, 1990 |
| Grant date | Mar 16, 1993 |
| Priority date | — |
| Expiry date | Jul 31, 2010 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N21/3151
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Methods and apparatus employing optical spectrometry techniques to measure metallic wear debris contamination in used motor oil, even in the presence of carbon particulates. Measurement results based on optical spectrometry as disclosed herein correlate closely with results of laboratory analysis based on atomic spectrometry. Variation in transmittance of a sample of oil as a function of wavelength within the approximate range of 300 nm (violet) to 1300 nm (near-infrared) is measured as an indicator of metallic wear debris contamination. Conveniently, measurements may be taken at just two wavelengths within the range, for example 565 nm (green) and 660 nm (red). The ratio of transmittance at the shorter of the two wavelengths to transmittance at the longer of the two wavelengths is determined as an indication of the amount of metallic wear debris contamination, decreases in the ratio from a ratio of unity indicating increasing levels of contamination. Oil degradation not necessarily accompanied by metallic wear debris contamination may also be measured.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.