Fuel injection system with accumulator fill valve assembly

A unit fuel injector comprising:

• a pump including a plunger in a pumping chamber;
• a nozzle that can be opened and closed by a control valve, wherein an injection event will occur when the control valve is actuated and will not occur when the control valve is not actuated;
• an accumulator fluidly connected between the pump and the nozzle to store
• pressurize fuel at high pressure for injection events independent of the pump;
• a fuel supply for supplying fuel to the pump and to the nozzle by way of the accumulator;
• and
• an accumulator fill valve assembly mounted between the pump and the nozzle in high pressure fluid communication with the accumulator and operable between an open condition and a closed condition, wherein the accumulator fill valve assembly has an inlet conduit in fluid communication with the pumping chamber and a restriction in the inlet conduit to establish a self enhanced pressure amplifier across the accumulator valve.

A fuel injection system comprising:

• a pump system including a plunger in a pumping chamber;
• an injector having a nozzle that can be opened and closed by a control valve, wherein an injection event will occur when the control valve is actuated and will not occur when the control valve is not actuated;
• an accumulator fluidly connected between the pump system and the injector to store pressurized fuel at high pressure for injection events independent of the pump system;
• and
• a fuel supply for supplying fuel to the pump system and to the injector by way of the accumulator;
• characterized by:
• an accumulator fill valve assembly mounted between the pump system and the injector in high pressure fluid communication with the accumulator and operable between an open condition and a closed condition, wherein the accumulator fill valve assembly comprises a spool, one portion of which is in fluid communication with the fuel supply, and another portion of which is in fluid communication with the accumulator, and the accumulator fill valve assembly has an inlet conduit in fluid communication with the pumping chamber and a restriction in the inlet conduit to establish a self enhanced pressure amplifier across the accumulator valve, whereby in the open condition, the accumulator is in fluid communication with the pumping chamber and in the closed condition, the accumulator is not in fluid communication with the pumping chamber and when pressure in the accumulator exceeds a set point the spool will be moved against pressure in the fuel supply to the closed condition.

A fuel injection system comprising:

• a pump system including a plunger in a pumping chamber;
• an injector having a nozzle that can be opened and closed by a control valve, wherein an injection event will occur when the control valve is actuated and will not occur when the control valve is not actuated;
• an accumulator fluidly connected between the pump system and the injector to store pressurized fuel at high pressure for injection events independent of the pump system;
• and
• a fuel supply for supplying fuel to the pump system and to the injector by way of the accumulator;
• characterized by:
• an accumulator fill valve assembly mounted between the pump system and the injector in high pressure fluid communication with the accumulator and operable between an open condition and a closed condition, wherein the accumulator fill valve assembly comprises a spool, one portion of which is in fluid communication with the fuel supply, and another portion of which is in fluid communication with the accumulator, whereby in the open condition, the accumulator is in fluid communication with the pumping chamber and in the closed condition, the accumulator is not in fluid communication with the pumping chamber.

A fuel injection system comprising:

• a pump system including a plunger in a pumping chamber;
• an injector having a nozzle that can be opened and closed by a control valve, wherein an injection event will occur when the control valve is actuated and will not occur when the control valve is not actuated;
• an accumulator fluidly connected between the pump system and the injector to store pressurized fuel at high pressure for injection events independent of the pump system;
• and
• a fuel supply for supplying fuel to the pump system and to the injector by way of the accumulator;
• characterized by:
• an accumulator fill valve assembly mounted between the pump system and the injector in high pressure fluid communication with the accumulator and operable between an open condition and a closed condition, wherein the accumulator fill valve assembly comprises a spool, one portion of which is in fluid communication with the fuel supply, and another portion of which is in fluid communication with the accumulator, and further comprising a conduit extending between the accumulator fill valve assembly and the top of the nozzle, whereby in the open condition, the accumulator is in fluid communication with the pumping chamber and in the closed condition, the accumulator is not in fluid communication with the pumping chamber.