Electroformed Multilayer Orifice Plate for Improved Fuel Injection Characteristics 971070
A new orifice plate (OP) for advanced fuel injection characteristics is presented. The OP is designed to optimize the air-fuel mixture generation and transportation within individually shaped manifold geometries of spark-ignition engines. To generate the suitable spray characteristics, the basic OP design and its flow characteristics have some features originating from the well known turbulence nozzle principle:
Turbulence generating flow deflections within the OP are achieved by superimposing layers containing flow cavities, which are displaced from one another. The flow deflections effect atomization and define the spatial spray beam orientation.
A great variety and a high volume of precisely structured, low cost OPs can be produced daily by micromachining the layers in electroformed nickel. The flow cavities and outer dimensions of each layer are shaped by photo-resist structures.
This paper describes the new OP's design development achieved through engine tests, flow simulations and experimental spray tests. A suitable OP manufacturing method is illustrated. For a wide range of flow rates, the new OP produces multiform spray shapes containing finely atomized, homogeneously distributed droplets. These characteristics are suitable for improving spray propagation and air-fuel mixture preparation.