Metodologias para análise e caracterização dos sprays de um injetor de injeção direta de gasolina

Abstract

The actual increasing demand for developing gasoline internal combustion engines with better efficiency and less CO2 concentration into the exhaust gases causes special attention to the direct injection engines. Some of the factors with significant influence on the performance of such engines are the spray characteristics directly injected into the combustion chamber. An effective atomization gives rises to a better advantage in the use of the fuel. Within its context, this study has the main purpose of settling strategies to examine critically theimportant parameters related to the sprays produced by a direct injection injector using water, gasoline and ethanol as tested fluids. The basis to the data acquisition for this study consisted of images related to the atomization process and the velocity fields obtained by Particle ImageVelocimetry. A mathematical strategy was settled to identify the sprays boundaries through a function and an appropriate reference system. The spray cone angle, the breakup length, the penetration, the rate of penetration, the droplet diameter, the linear velocity profiles and thevelocity profiles related to arcs centered on the orifice were important parameters of this work. The results showed high curvature related to the external spray boundaries, breakup length equals to 0,62 cm for water, 0,67 cm for ethanol and 0,78 cm for gasoline, penetration rates coherent with velocity fields got from PIV technique and good reproductibility of thetaken strategies of studying, suggesting an effective validation.