Patent attributes
Fuel injectors and methods of fuel injection allowing direct control of the flow of fuel at an intensified pressure to the needle. A valve, typically a spool valve, is placed in the fuel passage between the intensifier actuation piston and the needle, and controlled by a control valve which may be independent of the control valve controlling the coupling of actuation fluid and a vent to the intensifier actuation piston. This allows achievement of intensification before initiating injection, and control of multiple injections in a single injection event while maintaining fuel intensification throughout the duration of the injection event. Various embodiments are disclosed, including embodiments having multiple intensifiers, having control of pressure over the needle, having two stage control valve systems for control of intensifier actuation fluid, and combining control of one of the intensifiers and the valve controlling flow of intensified fuel to the needle for injection.
