DefinePK

Abstract

The fuel injection characteristics according to the injector driving pattern of a GDI (gasoline direct injection) injector were calculated by a computer simulation. The injector needle lift, fuel injection rate, and cumulative injected fuel mass were simulated by the computer. Five injector driving current patterns were used. The five injector current driving patterns combine peak & hold current waves. The fuel injection duration was increased in steps of 0.5 ms from 0.5 ms to 3.0 ms. The fuel injection durations for the computer simulation were greatly shorted to 0.25 ms. The fuel injection pressures for the simulation were 50 bar, 100 bar and 150 bar. As the fuel injection duration was shortened, the effects of the injector drive current pattern on the injector needle lift, fuel injection rate, and cumulative injected fuel mass became stronger. Specifically, the fuel injection characteristics of the GDI injector varied considerably with the variation of the driving current pattern at the fuel injection duration of 0.25 ms. The dynamic flow range (DFR) characteristics of the GDI injector were determined using the simulated results of the cumulative injected fuel mass. The DFR curve showed linear characteristics for all injector driving current patterns and fuel injection pressures in the fuel injection duration range of 0.5 ms - 3.0 ms.