Electrospray for Fuel Injection

Automotive fuel injectors have been adapted with electrodes that enable negative electric charge to be inserted into the fuel flowing through the injector. Because the fuel is electrically very insulating and flowing rapidly, a significant amount of charge is retained in the fuel as it issues from the injector. Once exposed to the atmosphere, the charge laden fuel both atomizes and spatially disperses due to electrostatic forces. By varying the amount of inserted charge, the spray pattern can be varied significantly. This added variability allows the possibility of changing the fuel presentation when fuel is injected into the intake port of a typical spark ignited engine. A variable presentation may be useful for optimizing fuel evaporation within the port, with a corresponding reduction of exhaust emissions, during the cold start period of the engine when those parameters affecting evaporation are changing both temporally and spatially. The present work describes the modification to the injectors with radially oriented electrodes, the electrical characteristics of the charge insertion (several μa at 2-4 kV), and the resulting spray patterns.