A Diagnostic for Simultaneous Liquid and Vapor Distributions in Sprays using Filtered Rayleigh and Mie Scattering

The understanding of how fuel evaporates and mixes when injected into an engine cylinder is of key importance for the design of cleaner, more efficient vehicles. To meet the Department of Energy & apos;s goals of improving fuel efficiency in gasoline engines by 25 percent and diesel engines by 40 percent, advanced tools for research on fuel injection dynamics are needed. Existing techniques for investigating pre- combustion spray and vaporization dynamics in an engine cylinder do not allow both liquid and fuel vapor to be imaged simultaneously, yet this is a critical need. The proposed effort by MetroLaser and the Ohio State University (OSU) involves combining filtered Rayleigh scattering (FRS) with Mie scattering to allow imaging of both liquid and vaporized fuel simultaneously. A sheet of laser light will illuminate the region of interest in the spray, and two cameras will view the laser sheet, one employing FRS that blocks scattering from droplets to measure only fuel vapor, and the other measuring only Mie-scattered light from the droplets. A strong absorption line of iodine is employed as a narrowband notch filter on the FRS camera to block the Mie-scattered light. In this proposed effort, we will explore the feasibility of the FRS/Mie technique for application to engines and engine simulator facilities to advance the state of the art in fuel injector research. The Phase I will involve establishing the quantitative aspects of the technique with modeling studies using single component fuels, followed by canonical experiments to demonstrate the validity of the modeling. Experiments will also be conducted to demonstrate the technique on a gasoline spray from a fuel injector, which should reveal the strengths and weaknesses of the approach and will provide information needed for adapting the technique to an engine in future studies. Commercial Applications and Other Benefits: The proposed diagnostic technique should help bring about significant improvements in energy efficiency and emissions reduction in vehicles by providing engine designers with a tool to better quantify fuel injector performance. Boosting the efficiency of internal combustion engines is one of the most promising and cost-effective approaches to increasing vehicle fuel economy. The Department of Energy estimates that the United States can cut its transportation fuel use 20 to 40 percent through commercialization of advanced engines.1 The technology development effort proposed here would provide a critically important capability to help achieve these potentials.