Experimental investigation of the possibility of automotive gasoline spray manipulation through electrostatic fields

An experimental evaluation of the possibility of using ‘electrospray’ in automotive technology. To this extent, a commercially available Gasoline Direct Injection (GDI) injector was modified in order to induce electrostatic charge in the non-conducting fuel spray. Spray morphology was characterised with visualisation experiments and spray structure was probed with Particle Image Velocimetry (PIV) and Fraunhofer light diffraction droplet size measurements. PIV data showed that electrostatically charged sprays presented pockets that were sparsely populated by droplets and areas of increased vortical motion at an injection pressure where the non-charged sprays were much more coherent. In this sense, electrostatic charging at relatively low pressures aided in the generation of flow patterns that are exhibited at higher pressures for non-charged sprays. Measurements of droplet diameter using a Fraunhofer light diffraction technique provided indications of increased resistance to droplet coalescence and a much smaller cyclic variation of droplet size for the electrostatically charged sprays.