Design of Electrical Driving Circuits for a High-pressure Fuel Injector and Control of Fuel Injection Quantities by using the Polynomial Curve Fitting Method

Abstract

Various electric driving circuits for the high-pressure (H.P.) GDI injector are required to be designed to be capable of rapid response and precise air-fuel ratio control for GDI engines. In this study, power transistors, IGBTs and power MOSFETs components are adopted respectively to design the electrical driving circuits for the H.P. GDI injector. The designed injector driving circuits are tested to verify its feasibility. The experiments for the GDI injection quantities are conducted under 60-100 bar fuel pressures, 1200~2000μs injecting pulse durations and DC 65V executing supply voltages. Also, the experimental fuel injection quantities of the high-pressure injector fed by the three-stage MOSFETs driving circuits can be modeled by using the polynomial curve fitting method. The polynomial mfuel(tp) equation of degree n fits the data of fuel injection quantities at different engine operating conditions. The fuel injection curve equations can be derived and implemented in developing the ECU to demonstrate its ability to control the fuel injection quantities and injection timing rapidly and precisely.