Single solenoid unit injector

A method of electronically operating a fuel injector disposed in operative relationship to a combustion chamber of an internal combustion engine, said injector including a body having an axially extending bore, a primary pumping plunger and a secondary plunger positioned therewithin for axial movement, a nozzle situated at one end of the body remote from the primary pumping plunger, a timing chamber defined in said body between said plungers, a metering chamber defined in said body between said secondary plunger and said nozzle, passages in said body for introducing fuel into said chambers, and electronically operated control valve means situated proximate said passages and said timing chamber, said method comprising the steps of:

• introducing fuel at supply pressure into said passages and said chambers;
• applying force to the primary pumping plunger to move same axially;
• supplying an electrical signal to the control valve means to seal the timing chamber and form a hydraulic link between the primary and secondary plungers and moving said plungers in concert;
• discharging the fuel in the metering chamber through the nozzle while maintaining the electrical signal;
• and
• terminating the electrical signal to the control valve means to open the timing chamber and break the hydraulic link between the plungers and moving said primary pumping plunger independently of said second plunger.

A fuel injector adapted to be disposed in operative relationship to the combustion chamber of an internal combustion engine, said injector comprising:

• a body having an axially extending central bore;
• a primary pumping plunger and a secondary plunger positioned within said body for axial movement;
• a nozzle situated at the end of the said central bore remote from said primary pumping plunger;
• a timing chamber defined in said body between said primary pumping plunger and said secondary plunger;
• a metering chamber defined in said body between said secondary plunger and said nozzle;
• passages in said body adapted to receive and transmit fuel to said timing chamber and said metering chamber;
• electronically operated control valve means for controlling the flow of fuel to and from said timing chamber, said control valve means operable in one position to prevent fuel from flowing out of said timing chamber thereby hydraulically coupling said primary plunger to said secondary plunger and operable in another position to allow fuel to flow out of said timing chamber thereby hydraulically uncoupling said primary and secondary plungers whereby when said valve is in said one position axial movement of said primary plunger towards said secondary plunger causes movement of said secondary plunger and hence fuel flow from said metering chamber and out of said nozzle.

A method of electronically operating a fuel injector disposed in operative relationship to a combustion cylinder of an internal combustion engine, said injector including a body having an axially extending bore, a primary pumping plunger positioned therewithin for axial movement, a nozzle situated at one end of the body from the primary pumping plunger, a metering chamber adjacent said nozzle, means separating said chamber from said plunger, passages in said body for flowing fuel in said injector, electronically operated control valve means controlling said passages, and an electronic control unit, said method comprising the steps of:

• introducing fuel at supply pressure into the passages and chamber.
• applying force to the primary pumping plunger to move the plunger axially;
• supplying an electrical signal to the control valve means;
• discharging the fuel through the nozzle and metering fuel for a subsequent discharge of fuel in response to the electrical signal;
• the start of said electrical signal initiating said discharge and the termination of said signal terminating metering;
• and said signal being maintained between said start and said termination.

A fuel injector for an internal combustion engine comprising;

• a body having an axially extending central bore;
• a primary pumping plunger and a secondary element positioned within said body for at least partial axial movement therein;
• a nozzle situated at the end of said central bore remote from said primary pumping plunger;
• a timing chamber defined in said body between said primary pumping plunger and said secondary element;
• a metering chamber defined in said body between said secondary element and said nozzle;
• passages in said injector for receiving pressurized fuel and transmitting said fuel into said timing chamber and said metering chamber;
• and
• an electromagnetic control element for controlling (1) the timing of the discharge of fuel from the metering chamber through the nozzle and (2) the quantity of fuel stored in said metering chamber subsequent to said discharge of fuel.

A method of operating a fuel injector disposed in operative relationship to a combustion chamber of an internal combustion engine, said injector including a body having an axially extending bore, a primary pumping plunger and a secondary element positioned therewithin for axial movement, a nozzle situated at one end of the body remote from the primary pumping plunger, a timing chamber defined in said body between said plunger and said element, a metering chamber defined in said body between said secondary element and said nozzle, passages for introducing fuel into said chambers, and control valve means situated proximate said passages and said timing chamber, said method comprising the steps of:

• introducing fuel at supply pressure into said passages and said chambers;
• applying force to the primary pumping plunger to move said plunger;
• operating the control valve to seal the timing chamber and form a hydraulic link between the primary plunger and secondary element and moving said plunger and element in concert;
• discharing the fuel in the metering chamber through the nozzle in response to the operation of the valve means;
• and
• terminating the operation of the control valve means to open the timing chamber and break the hydraulic link between the plunger and element and moving said primary plunger independently of said secondary element.

A fuel injector adapted to be disposed in operative relationship to the combustion chamber of an internal combustion engine, said injector comprising:

• a body having an axially extending central bore;
• a primary pumping plunger and a secondary element positioned within said body for at least partial axial movement;
• a nozzle situated at the end of the said central bore remote from said primary pumping plunger;
• a timing chamber defined in said body between said primary pumping plunger and said secondary element;
• a metering chamber defined in said body between said secondary element and said nozzle;
• passages in said body adapted to receive and transmit fuel to said timing chamber and said metering chamber;
• an electromagnetic control valve for controlling the flow of fuel to and from said timing chamber, and in turn to and from said metering chamber, said control valve means operable in one position to prevent fuel from flowing out of said timing chamber thereby hydraulically coupling said primary plunger to said secondary element and operable in another position to allow fuel to flow out of said timing chamber thereby hydraulically uncoupling said primary plunger and secondary element whereby when said valve is in said one position axial movement of said primary plunger in a direction towards said secondary element causes movement of at least a portion of said secondary element and hence fuel flow from said metering chamber and out of said nozzle, and axial movement in a direction away from said secondary element causes fuel flow into said metering chamber.

A fuel injector for controlling the flow of fuel to an internal combustion engine with a control valve comprising:

• a body having an axially extending central bore;
• a primary pump plunger and a secondary element positioned within said body for at least partial axial movement therein;
• a nozzle situated at the end of said central bore remote from said primary pumping plunger;
• a timing chamber defined in said body between said primary pumping plunger and said secondary element;
• a metering chamber defined in said body between said secondary element and said nozzle;
• passages in said body of said injector for receiving pressurized fuel and transmitting said fuel into said timing chamber and said metering chamber;
• and
• means for receiving the control valve for controlling (1) the timing of the discharge of fuel from the metering chamber through the nozzle and (2) the quantity of fuel stored in said metering chamber subsequent to said discharge of fuel, the control valve controlling both said timing and the quantity of fuel stored in said metering chamber.

A fuel injector adapted to be disposed in operative relationship to the combustion chamber of an internal combustion engine, the fuel injector being controlled by a control valve, said injector comprising:

• a body having a bore;
• a primary pumping plunger and a secondary element positioned for movement within said bore;
• a nozzle situated at the end of the said bore remote from said primary pumping plunger;
• a timing chamber defined in said body between said primary pumping plunger and said secondary element;
• a metering chamber defined in said body between said secondary element and said nozzle;
• passages in said body adapted to receive and transmit fuel to said timing chamber and said metering chamber;
• means formed to receive the control valve for controlling the flow of fuel to and from said timing chamber, the control valve means operable in one position to prevent fuel from flowing out of said timing chamber thereby hydraulically coupling said primary plunger to said secondary element and operable in another position to allow fuel to flow out of said timing chamber thereby hydraulically uncoupling said primary plunger and secondary element whereby when said valve is in said one position axial movement of said primary plunger in a direction towards said secondary element causes movement of at least a portion of said secondary element and hence fuel flow from said metering chamber and out of said nozzle, and axial movement in a direction away from said secondary element causes fuel flow into said metering chamber.