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

An electronically-controlled unit fluid pump injector comprising:

• a housing portion defining a fluid control passage and a fluid storage chamber;
• a first pressure control valve selectively movable between a first position opening fluid communication between the storage chamber and the control passage and a second position blocking fluid communication between the storage chamber and the control passage;
• a nozzle portion defining a pressure control chamber and at least one fluid injection orifice;
• a fluid pressurization member selectively movable between a first position and a second position, when the first valve is at its first position said member operable during movement from its first to second positions for displacing fluid from the storage chamber to the control passage, when the first valve is at its second position said member operable during movement from its first to second positions for displacing fluid in the storage chamber thereby pressurizing such fluid to a selected pressure;
• a direct-operated check selectively movable between a first position blocking fluid communication between the storage chamber and the fluid injection orifice and a second position opening fluid communication between the storage chamber and the fluid injection orifice, said check having a first end portion and a second end portion, said first end portion defining a first effective area arranged in fluid communication with the storage chamber when the check is at its second position, said second end portion defining a second effective area arranged in fluid communication with the pressure control chamber;
• and
• a second pressure control valve selectively movable between a first position and a second position, said second valve at its first position blocking fluid communication between the pressure control chamber and the control passage and opening fluid communication between the pressure control chamber and the storage chamber, said second valve at its second position opening fluid communication between the pressure control chamber and the control passage and blocking fluid communication between the pressure control chamber and the storage chamber, when the check is at its first position and the second valve is at its second position said first and second effective areas are operable for hydraulically moving the check towards its second position, when the check is at its second position and the second valve is at its first position said first and second effective areas are operable for balancing opposing hydraulic forces acting on such effective areas.

An electronically-controlled unit fuel pump injector comprising:

• a housing portion defining a fuel control passage and an integral fixed-volume fuel storage chamber;
• an electronically-controlled first pressure control valve positioned in the storage chamber, said first valve selectively movable between a de-energizeable first position opening fluid communication between the storage chamber and the control passage and an energizeable second position blocking fluid communication between the storage chamber and the control passage;
• a nozzle portion defining a bore, an injection chamber arranged in continuous fluid communication with the storage chamber, a separate pressure control chamber separate from the injection chamber, a tip seat, and at least one fuel injection orifice;
• a reciprocal fuel pressurization plunger positioned in the storage chamber, said plunger selectively movable between a first position and a second position, when the first valve is at its first position said plunger operable during movement from its first to second positions for displacing fuel from the storage chamber to the control passage, when the first valve is at its second position said plunger operable during movement from its first to second positions for displacing fuel in the storage chamber thereby pressurizing such fuel to a selected variable pressure;
• a direct-operated check positioned in the bore of the nozzle portion and selectively movable between a first position blocking fluid communication between the storage chamber and the fuel injection orifice and a second position opening fluid communication between the storage chamber and the fuel injection orifice, said check having a first end portion and a second end portion, said first end portion defining a first effective area arranged in partial fluid communication with the injection chamber when the check is at its first position, said first effective area arranged in complete fluid communication with the injection chamber when the check is at its second position, said second end portion defining a second effective area arranged in fluid communication with the pressure control chamber;
• a first spring operable for biasing the check towards its first position;
• an electronically-controlled second pressure control valve selectively movable between a de-energizeable first position and an energizeable second position, said second valve at its first position blocking fluid communication between the pressure control chamber and the control passage and opening fluid communication between the pressure control chamber and the injection chamber, said second valve at its second position opening fluid communication between the pressure control chamber and the control passage and blocking fluid communication between the pressure control chamber and the injection chamber, when the check is at its first position and the second valve is at its second position said first and second effective areas are operable for hydraulically moving the check towards its second position, when the check is at its second position and the second valve is at its first position said first and second effective areas are operable for balancing opposing hydraulic forces acting on such effective areas thereby allowing the first spring to move the check towards its first position;
• and
• a second spring operable for biasing both the first and second pressure control valves towards their respective first positions.

An electronically-controlled fuel injection system adapted for an engine comprising:

• a housing defining a fuel control passage and a fuel storage chamber;
• a first pressure control valve operable to selectively open and close fluid communication between the storage chamber and the control passage;
• a fuel pressurization member selectively movable between a first position and a second position, when the first valve is opened said member operable during movement from its first to second positions for displacing fuel from the storage chamber to the control passage, when the first valve is closed said member operable during movement from its first to second positions for displacing fuel in the storage chamber thereby pressurizing such fuel to a selected pressure;
• an actuation device operable for selectively actuating the member for movement between its first and second positions;
• an electronically-controlled injector including a nozzle portion and a movable direct-operated check, said nozzle portion defining a pressure control chamber and at least one fuel injection orifice, said check operable to selectively close and open fluid communication between the storage chamber and the fuel injection orifice, said check having a first end portion and a second end portion, said first end portion defining a first effective area arranged in partial fluid communication with the storage chamber when the check is closed, said first effective area arranged in complete fluid communication with the storage chamber when the check is opened, said second end portion defining a second effective area arranged in fluid communication with the pressure control chamber;
• and
• a second pressure control valve selectively movable between a first position and a second position, said second valve at its first position closing fluid communication between the pressure control chamber and the control passage and opening fluid communication between the pressure control chamber and the storage chamber, said second valve at its second position opening fluid communication between the pressure control chamber and the control passage and closing fluid communication between the pressure control chamber and the storage chamber, when the check is closed and the second valve is at its second position said first and second effective areas are operable for hydraulically opening the check, when the check is opened and the second valve is at its first position said first and second effective areas are operable for balancing opposing hydraulic forces acting on such effective areas.

A method of operating an electronically-controlled unit fuel pump injector comprising the steps of:

• opening fluid communication between a fixed-volume fuel storage chamber and a control passage;
• closing fluid communication between the storage chamber and at least one fuel injection orifice;
• displacing a variably-selected volume of fuel from the storage chamber to the control passage;
• closing fluid communication between the storage chamber and the control passage;
• displacing another variably-selected volume of fuel in the storage chamber and thereby pressurizing the fuel to a selected pressure;
• opening fluid communication between the storage chamber and the fuel injection orifice to begin fuel injection;
• and
• closing fluid communication between the storage chamber and the fuel injection orifice to end fuel injection.

A method of operating an electronically-controlled unit fuel pump injector comprising the steps of:

• opening fluid communication between a fixed-volume fuel storage chamber and a control passage;
• closing a check to block fluid communication between the storage chamber and at least one fuel injection orifice;
• displacing a variably-selected volume of fuel from the storage chamber to the control passage;
• closing fluid communication between the storage chamber and the control passage;
• displacing another variably-selected volume of fuel in the storage chamber and thereby pressurizing the fuel to a selected pressure;
• biasing the check towards a closed position blocking fluid communication between the storage chamber and the fuel injection orifice;
• hydraulically-unbalancing the check for movement towards an opened position opening fluid communication between the storage chamber and the fuel injection orifice;
• and
• hydraulically-balancing the check and allowing the biased check to move to the closed position.

A method of injecting fuel into a combustion chamber of an internal combustion engine using a fuel injector having an injector body, a check disposed in the injector body and movable between injecting and non-injecting positions, a spring urging the check into the non-injecting position and means coupled to the check ends for selectively coupling either high or low fluid pressures thereto, comprising the steps of:

• (a.) controlling the coupling means to cause the high fluid pressure to be applied to the first and second check ends;
• (b.) thereafter controlling the coupling means to cause the low fluid pressure to be applied to the first check end while the high fluid pressure is being applied to the second check end so that the check is moved to the injecting position against the urging of the spring;
• and
• (c.) thereafter controlling the coupling means to cause the high fluid pressure to be applied to the first and second check ends so that the check is moved to the non-injecting position in response to the urging of the spring.

A method of injecting fuel into a combustion chamber of an internal combustion engine using a unit injector having an injector body, a high pressure storage volume disposed in the injector body, a plunger extending into the high pressure storage volume and movable to pressurize fuel therein, a check disposed in the injector body having first and second check ends of substantially equal effective cross-sectional dimensions and movable between injecting and non-injecting positions, a pressure control valve in fluid communication with the high pressure storage volume and a poppet valve in fluid communication between the check ends and the high pressure storage volume and a source of low fluid pressure, comprising the steps of:

• (a.) providing a solenoid in the injector body having a first armature coupled to the pressure control valve, a second armature coupled to the poppet valve and a winding energizable to cause the armatures to be displaced relative to one another;
• (b.) energizing the winding as the plunger is moving into the high pressure storage volume to cause the pressure control valve to close the high pressure storage volume and pressurize fuel therein;
• (c.) deenergizing the winding to place the first and second check ends in fluid communication with the high pressure storage volume;
• and
• (d.) energizing the winding again to place the first check end in fluid communication with the source of low fluid pressure and the second check end in fluid communication with the high pressure storage volume so that a pressure differential across the check moves the check to the injecting position and initiates fuel injection.