The laser-induced fluorescence fiber-optic measurement of fuel in oil technology enables a user to measure the accumulation of fuel in engine oil, which can occur as fuel-efficient engines are operated in advanced modes to meet increasingly lower emissions regulations. Fuel found in oil is also associated with the use of biodiesel and fuel injection system control for modern diesel particulate filters. The fuel thins the oil, lowers its lubricating ability, and can lead to higher engine wear, increased oil consumption and, in extreme cases, engine failure.

The technology uses a laser and fuel tagged with a fluorescent dye to detect the fuel that has mixed with the oil. When the laser illuminates the diluted oil, it excites the dye and, as the dye returns to its unexcited state, it fluoresces. The emitted light is transmitted to an instrument that determines and records the amount of fuel in the oil. Conventional techniques require sending a sample of the oil to an analytical laboratory, resulting in up to two days’ delay for results. This new technology can take measurements at many different points in an engine system with a small fiber-optic probe; the technique is portable and provides real-time in situ feedback.

The technology was developed under a Cooperative Research and Development Agreement (CRADA) project with Cummins, Inc., which raised the need to measure the fuel dilution of oil. Commercialization of the technology began with a patent license agreement between UT-Battelle, LLC (the management and operations contractor for ORNL) and DaVinci Emissions Services, Ltd.

The benefit of the technology transfer effort is that a small niche market is now able to operate with significantly improved technology—faster, less expensive, and capable of detecting fuel contamination in lower amounts than other methods. As a result, monitoring oil dilution in an engine can be done in situ, which will enable faster improvements to engine efficiency and reduce emissions while reducing product development costs.