Electronically-controlled fluid injector system having pre-injection pressurizable fluid storage chamber and direct-operated check

A directly controlled unit injector, comprising:

• a first valve for controlling pressurization of fuel;
• a second valve for controlling injection of pressurized fuel;
• and
• a single actuator for controlling the first and second valves.

A unit fuel injector adapted to receive fuel from a fuel supply at relatively low pressure and inject fuel at relatively high pressure into a combustion chamber of an internal combustion engine over a series of injector cycles comprising:

• (a) an injector body containing an internal bore and an injector valve means;
• (b) a plunger mounted for reciprocating movement at varying velocity within said internal bore;
• (c) a high pressure storage volume into which fuel is received at low pressure from the fuel supply and from which fuel is discharged periodically at relatively high pressure through said injector valve means into the combustion chamber;
• and
• (d) injection control means for causing an amount of fuel to be injected at a selected time through the injector valve at a pressure which is independent of:
• (1) the pressure of fuel received from the fuel supply;
• (2) changes in the velocity of the reciprocating movement of said plunger;
• (3) the amount of fuel delivered through the injector valve means;
• and (4) the quantity, injection pressure, or timing of previous injection cycles.