The Influence of Fuel Boiling Temperature on Common Rail Spray Penetration and Mixture Formation for Ethanol and Propylene-Glycol

An intricate experimental investigation of Common-Rail-Sprays were done using a High Pressure Chamber, a Common-Rail-Injection-System as well as three optical measurement techniques. Ethanol and Propylene-Glycol (of purity for spectroscopic applications >99.9%) were used as fuels. The experimental boundary conditions of the high pressure chamber were up to 5 MPa and 800K. In detail an optical shadowgraph imaging and Mie-scattering technique were used. Liquid and gas phase spray penetration are investigated for fuels with low and high volatility respectively boiling temperature (propylene glycol, ethanol) for a variation of ambient gas phase temperature and density. Spatial information of the mixing process of both fuels is obtained by the 1D spontaneous Raman scattering (1D-RS) technique. That technique provides quantitative mass fraction respectively fuel-air ratio data [1] over a wide temperature and pressure range without the need of a tracer as for many techniques that are based on fluorescence (LIF). A briefly discussion as well as a comparison of these results of the two investigated fuels will be done.