High-pressure electromagnetic fuel injector

摘要

A high-pressure electromagnetic fuel injector having a dual-function valve directly controlled by an electric solenoid. Fuel pressure in a control volume chamber is controlled by the dual-function valve, and a separate control valve is controlled as a function of fuel pressure in the control volume chamber. A spray tip valve is, in turn, controlled as a function of the pressure of fuel controlled by the control valve to inject fuel through a spray tip orifice. The dual-function valve spills fuel during and after the control valve closes, thus reducing the amount of uncontrolled fuel at the end of an injection. The dual-function valve also provides a drain path through which to vent any fuel that leaks past the control valve.