Micro-machined diesel injector nozzles have been designed, fabricated and used with commercially produced diesel injection systems in the study of spray dynamics. Such a system, properly designed, may improve spray behavior in DI diesel engines due to improved atomization and fuel-air mixing.
In this work, fourteen micro-planar orifice nozzles were fabricated using the MEMS (Micro-Electro-Mechanical-Systems) technique. Circular orifice diameters were varied from 40 to 260 microns and the number of orifices was varied from one to 169. Three plates with non-circular orifices were also fabricated to examine the effect of orifice shape on spray characteristics. These nozzles were then attached to commercial injectors and the associated injection systems were used for the spray experiments.
Given these novel injection systems, jet spray characteristics of micro-planar orifice nozzles were investigated experimentally using optical diagnostic techniques in a pressurized constant volume cylindrical chamber. Local drop sizes were measured by the laser diffraction technique, and average drop sizes of the whole sprays were measured by the light extinction