Tang, M., Zhang, J., Zhu, X., Yeakle, K. et al., "Comparison of Direct-Injection Spray Development of E10 Gasoline to a Single and Multi-Component E10 Gasoline Surrogate," SAE Int. J. Fuels Lubr. 10(2):2017, doi:10.4271/2017-01-0833.
Optical and laser diagnostics enable in-depth spray characterization in regards to macroscopic spray characteristics and in-situ fuel mixture quality information, which are needed in understanding the spray injection process and for spray model development, validation and calibration. Use of fuel surrogates in spray researches is beneficial in controlling fuel parameters, developing spray and combustion kinetic models, and performing laser diagnostics with known fluorescence characteristics. This study quantifies and evaluates the macroscopic spray characteristics of a single and multi-component surrogate in comparison to a gasoline with 10% ethanol under gasoline direct injection (GDI) engine conditions. In addition, the effect of fuel tracers on spray evolution and vaporization is also investigated. Both diethyl-methyl-amine/fluorobenzene as a laser-induced exciplex (LIEF) fluorescence tracer pair and 3-pentanone as a laser-induced fluorescence (LIF) tracer are examined. The spray is issued from a seven-hole production GDI injector and investigated in an optically-accessible spray and combustion vessel. Optical diagnostics include shadowgraph and Mie scattering, and the images are analyzed to reveal the characteristic spray penetration curves and the vaporization process of different fuels. Results reveal the ability of fuel surrogates in representing the target fuel and the effect of the tracer’s addition to the surrogate. While many past spray characterization works using laser diagnostics in which fuel surrogates and tracers were used assumed the spray characteristics of the surrogate/tracer mixture were similar to those of the real fuel, the assumption is fully addressed in this work, which is part of a study in which in-situ characterization of the local equivalence ratio is performed based upon the results from this work.