Injection system of an internal combustion engine and automotive vehicle including such an injection system

Patent metadata

Field	Value
Publication number	US-10550808-B2
Application number	US-201415531450-A
Country	US
Kind code	B2
Filing date	Dec 19, 2014
Priority date	Dec 19, 2014
Publication date	Feb 4, 2020
Grant date	Feb 4, 2020

Abstract

A fuel injection system of an internal combustion engine includes: an injector having a hydraulic control chamber controlling the delivery of fuel through the injector, an actively controlled first valve system controlling the pressure relief from the control chamber, movable between: a first position in which the first valve system closes the injector by deterring the pressure from being relieved from the control chamber through the first relief circuit, and a second position in which the first valve system opens the injector by allowing the pressure to be relieved from the control chamber through the first relief circuit. A second relief circuit allows the pressure to be relieved from the control chamber through the second relief circuit. The second relief circuit includes a second valve system passively controlled by the fuel pressure and movable between two positions deterring or allowing the pressure to be relieved from the control chamber through the second relief circuit.

First claim

The invention claimed is:

1. A fuel injection system of an internal combustion engine, comprising:
an injector having a first hydraulic control chamber with a first pressure controlling the delivery of fuel through the injector;
an actively controlled first valve system controlling pressure relief from the first control chamber, the first valve system being movable between
a first position in which the first valve system closes the injector by deterring the first pressure from being relieved from the first control chamber through the first relief circuit, and
a second position in which the first valve system opens the injector by allowing the first pressure to be relieved from the first control chamber through a first relief circuit;
a second relief circuit allowing the first pressure to be relieved from the first control chamber;
a needle, wherein the first pressure in the first control chamber controls the position of the needle and the delivery of fuel through a nozzle;
wherein the second relief circuit comprises a second valve system controlled by a second pressure in a second control chamber independently of the position of the needle, the second valve system having a control port passively controlled by the first pressure and movable between
a first position in which the second valve system deters the pressure from being relieved from the first control chamber through the second relief circuit and
a second position in which the second valve system allows the pressure to be relieved from the first control chamber through the second relief circuit.

2. Fuel injection system according to claim 1 , wherein the first valve system includes a first directional control valve having a first port designed to be connected to a high pressure fuel source.

3. Fuel injection system according to claim 1 , wherein the first relief circuit includes a first relief line having a first flow resistance for controlling a flow rate of the fuel relieved from the first control chamber.

4. Fuel injection system according to claim 3 , wherein during a first injection phase in which the first pressure is relieved from the first control chamber through the first relief circuit and in which the second valve system deters the first pressure from being relieved from the first control chamber through the second relief circuit, a first speed of increase of an injection rate is determined by the first flow resistance.

5. Fuel injection system according to claim 1 , wherein the second relief circuit includes a second relief line having a second flow resistance for controlling a flow rate of the fuel relieved from the first control chamber.

6. Fuel injection system according to claim 1 , wherein in a second injection phase in which pressure is relieved from the first control chamber through the second relief circuit, a second speed of increase of the injection rate is determined.

7. Fuel injection system according to claim 4 , wherein in a second injection phase in which pressure is relieved from the first control chamber through the second relief circuit, a second speed of increase of the injection rate is determined, and wherein the second speed of increase is higher than the first speed of increase.

8. Fuel injection system according to claim 4 wherein in a second injection phase in which pressure is relieved from the first control chamber through the second relief circuit, a second speed of increase of the injection rate is determined, wherein the control port of the second valve system is connected to
an opening control line having a flow resistance, for adjusting a timing between the first injection phase and the second injection phase, and
a closing control line having a smaller flow resistance than the opening control line and equipped with a check valve preventing flow of fuel from the control port of the second valve system.

9. Fuel injection system according to claim 1 , wherein the first valve system includes a first directional control valve electromagnetically controlled by an electronic control unit.

10. Fuel injection system according to claim 1 , wherein the first valve system includes a mechanical return device for returning the first valve system to the first position.

11. Fuel injection system according to claim 1 , wherein the second valve system includes mechanical return means for returning the second valve system to the first position.

12. Fuel injection system according to claim 1 , wherein the injection system includes a third flow resistance for adjusting the closing speed of the injector.

13. Fuel injection system according to claim 1 , wherein the injection system includes
a pressure feed line for feeding the first control chamber with pressurized fuel, the pressure feed line being equipped with a first check valve preventing flow of fuel from the first control chamber, and
a first relief line in parallel with the pressure feed line and having a first flow resistance, for relieving fuel from the first control chamber though the first valve system.

14. Fuel injection system according to claim 13 , wherein the injection system includes a third flow resistance for adjusting a closing speed of the injector, and wherein the third flow resistance for adjusting the closing speed of the injector is located in the pressure feed line.

15. Fuel injection system according to claim 1 , wherein when the pressure in the first control chamber is above a pressure threshold, the needle closes the nozzle and wherein, when the pressure in the first control chamber is below the pressure threshold, the needle opens the nozzle.

16. Fuel injection system according to claim 1 , wherein the injector system includes a mechanical return device applying a closing force to the needle for maintaining the needle in a closed position.

17. Fuel injection system according to claim 1 , wherein the first valve system and the second valve system are integrated in a common body part and wherein the needle is disposed in a pressure chamber having the nozzle for fuel delivery, the pressure chamber being located inside the body part.

18. Fuel injection system according to claim 1 , wherein the needle is movable in a pressure chamber by means of a difference in pressure between the first control chamber and the pressure chamber.

19. Fuel injection system according to claim 1 , wherein, in the first position of the first valve system the first pressure is delivered to the first control chamber through the first valve system.

20. An automotive vehicle comprising the fuel injection system according to claim 1 .

Assignees

• Volvo Truck Corp

Inventors

• Millet Guillaume

Classifications

• F02M47/022

  Mechanically actuated valves draining the chamber to release the closing pressure · CPC title

• F02M55/008

  Arrangement of fuel passages inside of injectors · CPC title

• F02M63/0035

  Poppet valves, i.e. having a mushroom-shaped valve member that moves perpendicularly to the plane of the valve seat · CPC title

• F02M63/0017

  using electromagnetic operating means · CPC title

• F02M2200/28

  Details of throttles in fuel-injection apparatus · CPC title