초록 ▼

A fuel injection metering valve has a first fuel outlet for supplying fuel to a first accumulator volume, a second fuel outlet for supplying fuel to a second accumulator volume, valving for controlling fuel flow to the first and second fuel outlets, a first flow path for exposing the valving to fuel

A fuel injection metering valve has a first fuel outlet for supplying fuel to a first accumulator volume, a second fuel outlet for supplying fuel to a second accumulator volume, valving for controlling fuel flow to the first and second fuel outlets, a first flow path for exposing the valving to fuel pressure representative of fuel pressure in the first accumulator volume and a second flow path for exposing the valving to fuel pressure representative of fuel pressure in the second accumulator volume. The valving is responsive to the representative fuel pressures to control the fuel supply from the second fuel outlet to the second accumulator volume as a function of the fuel pressure in the first accumulator volume. The fuel injection metering valve can be used in a dual-fuel fuel injection system to control the flow of one fuel such that it follows the controlled pressure of a different fuel, so that it is not necessary to provide duplication control components in the fuel injection system.

대표청구항 ▼

The invention claimed is: 1. A fuel injection metering valve comprising: a first fuel outlet for supplying fuel to a first accumulator volume, a second fuel outlet for supplying fuel to a second accumulator volume, valving for controlling fuel flow to said first and second fuel outlets, a first flo

The invention claimed is: 1. A fuel injection metering valve comprising: a first fuel outlet for supplying fuel to a first accumulator volume, a second fuel outlet for supplying fuel to a second accumulator volume, valving for controlling fuel flow to said first and second fuel outlets, a first flow path for exposing said valving to a fuel pressure representative of fuel pressure in said first accumulator volume and a second flow path for exposing said valving to fuel pressure representative of fuel pressure in said second accumulator volume, said valving being responsive to said representative fuel pressures to control the fuel supply from said second fuel outlet to said second accumulator volume as a function of the fuel pressure in said first accumulator volume. 2. A fuel injection metering valve as claimed in claim 1, further comprising at least one biasing element acting on said valving such that, in use, there is a fuel pressure difference between said first accumulator volume and said second accumulator volume that is at least in part determined by said at least one biasing element. 3. A fuel injection metering valve as claimed in claim 1, wherein said valving comprises a valve member that is axially slideable in respective opposed directions in response to said representative fuel pressures, said valve member being provided with a projection that is slideably received in a passage defined by a member that is able to move radially with respect to the valve member axis. 4. A fuel injection metering valve as claimed in claim 1, wherein said valving comprises respective pressure receiving portions exposed to said first and second representative fuel pressures, and is provided with at least one projection that is exposed to a different pressure for at least in part determining a pressure difference between said first accumulator volume and said second accumulator volume. 5. A fuel injection metering valve as claimed in claim 1, wherein said valving is provided with a projection that is axially slideable in a passage and arranged to vent one of said first flow path and said second flow path via said passage. 6. A fuel injection metering valve as claimed in claim 5, wherein the projection is biased into engagement with a valve seat. 7. A fuel injection metering valve as claimed in claim 1, wherein said valving comprises respective pressure receiving portions exposed to said first and second representative fuel pressures and arranged such that the fuel pressure in said second accumulator volume is controlled to be substantially equal to the fuel pressure in said first accumulator volume. 8. A fuel injection metering valve as claimed in claim 1, wherein, to reduce the pressure in one of said first or second accumulator volumes, the metering valve acts to decrease the fuel supply from said first or second fuel outlets, respectively; and wherein, to increase the pressure in one of said first or second accumulator volumes, the metering valve acts to increase the fuel supply from said first or second fuel outlets, respectively. 9. A fuel injection metering valve as claimed in claim 1, wherein the first and second accumulator volumes are first and second common rails. 10. A fuel pump having an integral fuel injection metering valve as claimed in claim 1, said pump comprising pumping apparatus for separately pumping and outputting respective fuel flows received from said first and second fuel outlets. 11. A fuel injection system comprising a fuel injection metering valve configured, in use, to supply a first fuel output and a second fuel output to a first accumulator volume and a second accumulator volume, respectively; and having valving in flow communication with respective flow paths that, in use, expose respective pressure receiving portions of the valving to respective fuel pressure flows indicative of the fuel pressures in said first and second accumulator volumes; said valving being responsive to said pressure flows to cause the fuel pressure in said second accumulator volume to follow the fuel pressure in the first accumulator volume. 12. A fuel injection system as claimed in claim 11, wherein said valving is associated with at least one device that causes the fuel pressure in said second accumulator volume to be different to the fuel pressure in said first accumulator volume by a predetermined amount. 13. A fuel injection system as claimed in claim 12, wherein said at least one device comprises at least one of a biasing member acting on said valving, and a member connected to said valving and exposed to a relatively low pressure for modifying the effect of the exposure of said valving to at least one of said pressure flows indicative of the fuel pressure in said first and second accumulator volumes. 14. A fuel injection system as claimed in claim 12, wherein said at least one device comprises a member connected to the valving and exposed to a relatively low pressure, said member projecting from said valving into a passage of a passage defining member and being axially slideable in said passage, said passage defining member being free to move radially with respect to the axis of sliding. 15. A fuel injection system as claimed in claim 11, comprising a venting device for venting pressure from the flow path that exposes the valving to the pressure flow indicative of the fuel pressure in said second accumulator volume. 16. A fuel injection system as claimed in claim 11, comprising at least one valve disposed upstream or downstream of said fuel injection metering valve and operable to receive commands for adjusting the fuel pressure in said flow path. 17. A fuel injection system as claimed in claim 11, comprising a fuel pump for receiving said first and second fuel outputs and selectively pumping said outputs to the respective first and second accumulator volumes. 18. A fuel injection system as claimed in claim 11, further comprising at least a first set of fuel injectors for receiving fuel from said first and said second accumulator volumes. 19. A fuel injection system as claimed in claim 18, which comprises a first set of fuel injectors for receiving fuel from said first accumulator volume and a second set of fuel injectors for receiving fuel from said second accumulator volume. 20. A fuel injection system as claimed in claim 11, wherein the first and second accumulator volumes are first and second common rails. 21. A fuel delivery system comprising a fuel injection system as claimed in claim 11 and respective fuel reservoirs connected with said fuel injection metering valve for supplying the fuels for said first and second fuel outputs. 22. A method of controlling fuel pressure in a fuel injection system, said method comprising: pumping a first fuel from a fuel reservoir into a first accumulator volume, pumping a second fuel from a second fuel reservoir into a second accumulator volume, setting a delivery pressure for said first fuel from said first accumulator volume, exposing a valve member to a source of said first fuel that is at a pressure indicative of said delivery pressure and exposing said valve member to a source of said second fuel at a pressure indicative of a delivery pressure of said second fuel; said valve member being operable to respond to the respective pressures indicative of delivery pressure to cause the delivery pressure of said second fuel to be substantially maintained in fixed relation to the delivery pressure of said first fuel. 23. A method as claimed in claim 22, wherein said valve member is movable in respective opposite directions by exposure to said first and second fuels from said respective sources. 24. A method as claimed in claim 22, wherein said first and second fuels are different fuels.