Claims:We Claim

1. A fuel flow system (10) positioned between a leak ports (12,15) of a high pressure fuel pump (13) / fuel injectors (15) and a pressure limiting valve (14) of a high pressure rail (16) and a fuel tank (18), the fuel flow system (10) comprising:
a first fuel flow path (20) positioned between the leak ports (12) of the high pressure fuel pump (13) / fuel injectors (15), and a second fuel flow path (22), the second fuel flow path (22) adapted to house a solenoid valve (24) therein, wherein the solenoid valve (24) is adapted to be electrically actuated;
a third fuel flow path (26) positioned between the second fuel flow path (22) and an outlet (27) of the pressure limiting valve (14) of the high pressure rail (16), the third fuel flow path (26) adapted to deliver pressurized fuel that flows through the first fuel flow path (20) to the outlet (27) of the pressure limiting valve (14); and
a fourth fuel flow path (28) positioned between the third fuel flow path (26) and the fuel tank (18) of a vehicle, the fourth fuel flow path (28) adapted to deliver pressurized fuel from the outlet (27) of the pressure limiting valve (14) to the fuel tank (18) of the vehicle via the third fuel flow path (26).

2. The fuel flow system (10) positioned between the leak ports (12,15) of the high pressure fuel pump (13) / fuel injectors (15), and the pressure limiting valve (14) of the high pressure rail (16) and the fuel tank (18) in accordance with Claim 1, wherein the solenoid valve (24) that is housed within the second fuel flow path (22) is adapted to reciprocate within the second fuel flow path (22) to facilitate controlling a flow of fuel between the leak port (12) of the high pressure fuel pump (13) and the outlet (27) of the pressure limiting valve (14) and to the fuel tank (18) of the vehicle.

3. The fuel flow system (10) positioned between the leak ports (12,15) of the high pressure fuel pump (13) / fuel injectors (17) and the pressure limiting valve (14) of the high pressure rail (16) and the fuel tank (18) in accordance with Claim 1, further comprising an actuator (30) in electronic communication with the solenoid valve (24), the actuator (30) adapted to actuate the solenoid valve (24) to facilitate controlling the flow of fuel from the leak ports (12,15) of the high pressure fuel pump (13) / fuel injectors (17) to the outlet (27) of the pressure limiting valve (14), from the outlet (27) of the pressure limiting valve (14) to the fuel tank (18), and from the leak port (12) of the high pressure fuel pump (13) to the fuel tank (18).

4. The fuel flow system (10) positioned between the leak ports (12,15) of the high pressure fuel pump (13) / fuel injectors (17) and the pressure limiting valve (14) of the high pressure rail (16) and the fuel tank (18) in accordance with Claim 3, further comprising a spring element (32) positioned between the actuator (30) and the solenoid valve (24), the spring element (32) adapted to restore the solenoid valve (30) to its original position when the actuator (30) is deactivated.

5. The fuel flow system (10) positioned between the leak ports (12,15) of the high pressure fuel pump (13) / fuel injectors (17) and the pressure limiting valve (14) of the high pressure rail (16) and the fuel tank (18) in accordance with Claim 4, further comprising an engine control unit (34) in electronic communication with the actuator (30), the engine control unit (34) adapted to activate the actuator (30), wherein the activation of the actuator (30) translates the solenoid valve (24) that is housed within the second fuel flow path (22) to facilitate controlling a flow of pressurized fuel between the leak port (12) of the high pressure fuel pump (13) and the outlet (27) of the pressure limiting valve (14).

6. The fuel flow system (10) positioned between the leak ports (12,15) of the high pressure fuel pump (13) / fuel injectors (17) and the pressure limiting valve (14) of the high pressure rail (16) and the fuel tank (18) in accordance with Claim 5, wherein the engine control unit (34) activates the actuator (30) that translates the solenoid valve (24) towards the actuator (30), the translation of the solenoid valve (24) towards the actuator (30) facilitates opening the third fuel flow path (26)0, thereby channeling pressurized fuel from the leak port (12) of the high pressure fuel pump (13) to the outlet (27) of the pressure limiting valve (14) via the first fuel flow path (20), via the second fuel flow path (22), and via the third fuel flow path (26), and wherein the actuator (30) facilitates closing the fourth fuel flow path (28), thereby preventing the flow of fuel from the leak port (12) of the high pressure fuel pump (13) to flow through the fourth fuel flow path (28).

7. The fuel flow system (10) positioned between the leak ports (12,15) of the high pressure fuel pump (13) / fuel injectors (17) and the pressure limiting valve (14) of the high pressure rail (16) and the fuel tank (18) in accordance with Claim 6, wherein the engine control unit (34) deactivates the actuator (30), the deactivation of the actuator (30) causes the spring element (32) that is positioned between the actuator (30) and the solenoid valve (24) to translate the solenoid valve (24) away from the actuator (30), the translation of the solenoid valve (24) away from the actuator (30) closes the third fuel flow path (26) and prevents the pressurized fuel from the third fuel flow path (26) from flowing out of the third fuel flow path (26), and wherein the actuator (30) facilitates opening the fourth fuel flow path (28), thereby allowing the flow of pressurized fuel from the leak port (12) of the high pressure fuel pump (13) to flow through the fourth fuel flow path (28) to the fuel tank (18).

8. The fuel flow system (10) positioned between the leak ports (12,15) of the high pressure fuel pump (13) / fuel injectors (17) and the pressure limiting valve (14) of the high pressure rail (16) and the fuel tank (18) in accordance with Claim 7, wherein the engine control unit (34) activates the actuator (30) partially, the partial activation of the actuator (30) causes the actuator (30) to partially translate the solenoid valve (24) towards the actuator (30), the partial translation of the solenoid valve (24) towards the actuator (30) opens the third fuel flow path (26) partially and allows the pressurized fuel from the third fuel flow path (26) to flow through the fourth fuel flow path (28) to the fuel tank (18), and wherein the actuator (30) facilitates opening the fourth fuel flow path (28) partially, thereby allowing the flow of pressurized fuel from the leak port (12) of the high pressure fuel pump (13) to flow through the fourth fuel flow path (28) to the fuel tank (18).

9. The fuel flow system (10) positioned between the leak ports (12,15) of the high pressure fuel pump (13) / fuel injectors (17) and the pressure limiting valve (14) of the high pressure rail (16) and the fuel tank (18) in accordance with Claim 7, wherein the engine control unit (34) activates the actuator (30) partially by supplying a partial supply of power to the actuator (30), thereby opening the third fuel flow path (26) and the fourth fuel flow path (28) partially, and allowing the flow of pressurized fuel from the leak port (12) and the flow of pressurized fuel from the outlet (27) of the pressure limiting valve (14) to flow through the fourth fuel flow path (28) to the fuel tank (18).
, Description:Complete Specification:

The following specification describes and ascertains the nature of this invention and the manner in which it is to be performed.
Field of the invention
[0001] This invention relates to a solenoid valve, and more specifically to the solenoid valve for controlling a flow of pressurized fuel to a pressure limiting valve of a high pressure rail.

Background of the invention
[0002] GB 2571284 A1 describes a pressure limiting valve, a common rail assembly and methods of tuning the common rail assembly. The pressure limiting valve comprises a body provided with a bore with a seat member at an end, surrounding a spill orifice. An adjustable valve assembly comprising a valve member, a spring, and a plug are arranged in the cavity. The position of the retainer can be adjusted and may compress the spring against the valve member. The seat may be integral with the body or a separate part. The disclosed fuel reservoir assembly is tuned by pre-assembling the pressure relieving valve, fixing it in the common rail and then tuning the pressure limiting valve to a target safety pressure threshold. The valve may be tuned by tightening or loosening the plug. The pressure limiting valve and common rail arrangement overcomes weakness issues encountered by valves that are crimped or use shims.

Brief description of the accompanying drawing
[0003] Figure 1 illustrates a fuel injection system illustrating a solenoid valve that channels pressurized fuel from leak ports of a high pressure fuel pump / fuel injectors to a pressure limiting valve of a high pressure rail and to a fuel tank.
[0004] Figure 2 illustrates a solenoid valve for controlling a flow of pressurized fuel from a leak ports of a high pressure fuel pump / fuel injectors to a pressure limiting valve of a high pressure rail and to a fuel tank.

Detailed description of the embodiments
[0005] A fuel flow system 10 positioned between a leak port 12 of a high pressure fuel pump 13 and a pressure limiting valve 14 of a high pressure rail 16 and a fuel tank 18 is described. The fuel flow system 10 comprises a first fuel flow path 20 positioned between the leak port 12 of the high pressure fuel pump 13 and a second fuel flow path 22. The second fuel flow path 22 is adapted to house a solenoid valve 24 therein, wherein the solenoid valve 24 is adapted to be electrically actuated. A third fuel flow path 26 is positioned between the second fuel flow path 22 and an outlet 27 of the pressure limiting valve 14 of the high pressure rail 16. The third fuel flow path 26 is adapted to deliver pressurized fuel that flows through the first fuel flow path 20 to the outlet 27 of the pressure limiting valve 14. A fourth fuel flow path 28 is positioned between the third fuel flow path 26 and the fuel tank 18 of a vehicle. The fourth fuel flow path 28 is adapted to deliver pressurized fuel from the outlet 27 of the pressure limiting valve 14 to the fuel tank 18 of the vehicle via the third fuel flow path 26.

[0006] Figure 1 illustrates a solenoid valve 24 for controlling a flow of pressurized fuel from leak ports (12,15) of a high pressure fuel pump 13 / fuel injectors 17 to a pressure limiting valve 14 of a high pressure rail 16. A fuel flow system 10 is positioned between a leak port 12 of a high pressure fuel pump 13 and a leak port 15 of a fuel injectors 17, and a pressure limiting valve 14 of a high pressure rail 16. In addition, the fuel flow system 10 is also positioned between the leak port 12 of the high pressure fuel pump 13 and the leak port 15 of the fuel injectors 17, and a fuel tank 18. The fuel flow system 10 comprises a first fuel flow path 20 that is positioned between the leak port 12 of the high pressure fuel pump 13 and a second fuel flow path 25. More specifically, the first fuel flow path 20 is a horizontally shaped fuel flow path that channels pressurized fuel from the leak port 12 of the high pressure fuel pump 13 to the second fuel flow path 25. The second fuel flow path 25 is orthogonally positioned with reference to the first fuel flow path 20, and is adapted to house a solenoid valve 24 therein. In the exemplary embodiment, the solenoid valve 24 is adapted to be electrically actuated to facilitate translating the solenoid valve 24 within the second fuel flow path 25, thereby facilitating pressurized fuel to be channeled from the leak ports (12,15) of the high pressure fuel pump 13 / fuel injectors 17 to the pressure limiting valve 14 of the high pressure rail 16.

[0007] In an exemplary embodiment, the second fuel flow path 25 is adapted to house a solenoid valve 24 therein. The solenoid valve 24 is adapted to be electrically actuated by means of an actuator 30 that is in electronic communication with the solenoid valve 24. A third fuel flow path 26 is positioned between the second fuel flow path 25 and an outlet 27 of a pressure limiting valve 14 of the high pressure rail 16. More specifically, the function of the third fuel flow path 26 is to deliver pressurized fuel that flows through the first fuel flow path 20 to the outlet 27 of the pressure limiting valve 14. More specifically, when the solenoid valve 24 is actuated, pressurized fuel is channeled from the first fuel flow path 20 to the outlet 27 of the pressure limiting valve 14 via the second fuel flow path 25 and via the third fuel flow path 26 respectively as will be explained in more detail below. In the exemplary embodiment, a fourth fuel flow path 28 is positioned between the third fuel flow path 26 and a fuel tank 18 of the vehicle. The function of the fourth fuel flow path 28 is to deliver pressurized fuel from the outlet 27 of the pressure limiting valve 14 to the fuel tank 18 of the vehicle via the third fuel flow path 26 as will be explained in more detail below.

[0008] In an exemplary embodiment, the solenoid valve 24 that is housed within the second fuel flow path 25 is adapted to reciprocate within the second fuel flow path 25. The reciprocating motion of the solenoid valve 24 that is housed within the second fuel flow path 25 facilitates controlling a flow of pressurized fuel between the leak ports (12,15) of the high pressure fuel pump 13 / fuel injectors 17 and the outlet 27 of the pressure limiting valve 14. In addition, the reciprocating motion of the solenoid valve 24 that is housed within the second fuel flow path 25 facilitates controlling a flow of pressurized fuel between the leak ports (12,15) of the high pressure fuel pump 13 / fuel injectors 17 and the fuel tank 18 of the vehicle. Furthermore, the reciprocating motion of the solenoid valve 24 that is housed within the second fuel flow path 25 facilitates controlling a flow of fuel between the leak ports (12,15) of the high pressure fuel pump 13 / fuel injectors 17 and the fuel tank 18 of the vehicle.

[0009] An actuator 30 is in electronic communication with the solenoid valve 24. More specifically, when the actuator 30 is activated, the actuator 30 is adapted to translate the solenoid valve 24 in the same direction of the actuator 30 within the second fuel flow path 25. When the solenoid valve 24 translates in the same direction of the actuator 30 due to the actuation of the solenoid valve 24, the third fuel flow path 26 is opened such that the third fuel flow path 26 is in flow communication with the second fuel flow path 28 and the first fuel flow path 20. Therefore, due to the opening of the third fuel flow path 26, pressurized fuel is adapted to flow from the leak ports (12,15) of the high pressure fuel pump 13 / fuel injectors 17 to the outlet 27 of the pressure limiting valve 14 via the first fuel flow path 20, via the second fuel flow path 25, and via the third fuel flow path 26 respectively. In the exemplary embodiment, a spring element 32 is positioned between the actuator 30 and the solenoid valve 24. The spring element 32 is adapted to be compressed when the actuator 30 is electronically activated, and the solenoid valve 24 is translated in the direction of the actuator 30, thereby opening the third fuel flow path 26 to the second fuel flow path 25 and the first fuel flow path 20 that is in flow communication with the leak ports (12,15) of the high pressure fuel pump 13 / fuel injectors 17. When the actuator 30 is deactivated, the energy stored in the compressed spring element 32 is released, thereby restoring the solenoid valve 24 back to its original position, thereby closing the third fuel flow path 26 from the second fuel flow path 25 and the first fuel flow path 20 that is in flow communication with the leak ports (12,15) of the high pressure fuel pump 13 / fuel injectors 17.

[0010] In an exemplary embodiment, an engine control unit 34 is in electronic communication with the actuator 30. The engine control unit 34 is adapted to activate the actuator 30. When the engine control unit 34 activates the actuator 30, the activation of the actuator 30 translates the solenoid valve 24 that is housed within the second fuel flow path 25 in the direction of the actuation of the actuator 30. The translation of the solenoid valve 24 that is housed within the second fuel flow path 25 in the direction of the actuator 30 facilitates controlling a flow of fuel between the leak ports (12,15) of the high pressure fuel pump 13 / fuel injectors 17 and the outlet 27 of the pressure limiting valve 14 via the first fuel flow path 20, the second fuel flow path 25, and via the third fuel flow path 26.

[0011] In an exemplary embodiment, the engine control unit 34 activates the actuator 30 that translates the solenoid valve 24 in the direction of the actuator 30. The translation of the solenoid valve 24 in the direction of the actuator 30 facilitates opening the third fuel flow path 26. The opening of the third fuel flow path 26 facilitates channeling pressurized fuel from the leak ports (12,15) of the high pressure fuel pump 13 / fuel injectors 17 to the outlet 27 of the pressure limiting valve 14 via the first fuel flow path 20, via the second fuel flow path 25, and via the third fuel flow path 26. When the solenoid valve 24 is translated in the direction of the actuator 30 thereby opening the third fuel flow path 26 to the leak ports (12,15) of the high pressure fuel pump 13 / fuel injectors 17, the fourth fuel flow path 28 is completely closed by the actuator 24. The closure of the fourth fuel flow path 28 by the actuator 24 prevents the flow of fuel from the leak ports (12,15) of the high pressure fuel pump 13 / fuel injectors 17 to the fuel tank 18 via the fourth fuel flow path 28. Instead, pressurized fuel is unilaterally channeled from the leak ports (12,15) of the high pressure fuel pump 13 / fuel injectors 17 to the outlet 27 of the pressure limiting valve 14 via the third fuel flow path 26.

[0012] When the third fuel flow path 26 is completely filled with fuel between the second fuel flow path 25 and the outlet 27 of the pressure limiting valve 14, the engine control unit 34 deactivates the actuator 30. The deactivation of the actuator 30 causes the spring element 30 that is positioned between the actuator 30 and the solenoid valve 24 to release its stored potential energy by applying a tensile force on the solenoid valve 24. The tensile force that is applied on the solenoid valve 24 causes the solenoid valve 24 to translate away from the actuator 30. The translation of the solenoid valve 24 away from the actuator 30 closes the third fuel flow path 26. The closure of the third fuel flow path 26 by the solenoid valve 24 retains the pressurized fuel within the third fuel flow path 26, and prevents the pressurized fuel from the third fuel flow path 26 from flowing out of the third fuel flow path 26 and into the fuel tank 18. Therefore, the outlet 27 of the pressure limiting valve 14 is lubricated sufficiently by the fuel that flows through the third fuel flow path 26 to the pressure limiting valve 14.

[0013] When the solenoid valve 24 closes the third fuel flow path 26, the actuator 30 facilitates opening the fourth fuel flow path 22. As the fourth fuel flow path 22 is opened, the pressurized fuel from the leak ports (12,15) of the high pressure fuel pump 13 / fuel injectors 17 flows through the first fuel flow path 20, via the second fuel flow path 25, and via the fourth fuel flow path 28 to the fuel tank 18. This constitutes the normal operation of the system, where pressurized fuel is delivered from the leak ports (12,15) of the high pressure fuel pump 13 / fuel injectors 17 to the fuel tank 18 via the first fuel flow path 20 and via the fourth fuel flow path 28 respectively.

[0014] When the pressure within the high pressure common rail 16 exceeds a critical threshold pressure, the pressure limiting valve 14 is opened. The opening of the pressure limiting valve 14 due to the fuel in high pressure common rail 16 exceeding the critical threshold pressure is sensed by a rail pressure sensor and transmitted to the engine control unit 34. When the pressure of the fuel in the high pressure common rail 16 increases above the critical threshold pressure, the engine control unit 34 activates the actuator 24 partially. The partial activation of the actuator 24 causes the actuator 24 to partially translate the solenoid valve 24 towards the actuator 30, thereby opening the third fuel flow path 26 partially. The partial opening of the third fuel flow path 26 allows the pressurized fuel that flows from the outlet of the pressure limiting valve 14 to flow through the third fuel flow path 26 and into the second fuel flow path 25. Pressurized fuel from the second fuel flow path 25 is channeled into the fourth fuel flow path 28 and finally discharged to the fuel tank 18. More specifically, as the third fuel flow path 26 is partially opened, the fourth fuel flow path 28 is partially opened as well. As the fourth fuel flow path 28 is partially opened, a first stream of pressurized fuel that exits from the high pressure rail 16 through the pressure limiting valve 14 flows into the fuel tank 18 via the third fuel flow path 28, via the second fuel flow path 25, and fourth fuel flow path 28 respectively. In addition, a second stream of pressurized fuel that exits from the leak ports (12,15) of the high pressure fuel pump 13 / fuel injectors 17 to flow through the fourth fuel flow path 28 to the fuel tank 18 via the first fuel flow path 20, and via the second fuel flow path 25.

[0015] In an exemplary embodiment, the engine control unit 34 activates the actuator 30 partially by supplying a partial quantity of power to the actuator 30 as compared to the maximum power that is required to fully actuate the actuator 30 to facilitate channeling pressurized fuel from the leak ports (12,15) of the high pressure fuel pump 13 / fuel injectors 17 to the third fuel flow path 26. Due to the partial actuation of the actuator 24, both the third fuel flow path 26 and the fourth fuel flow path 28 are opened partially, thereby allowing the pressurized fuel to flow from the leak ports (12,15) of the high pressure fuel pump 13 / fuel injectors 17 and the pressurized fuel to flow from the outlet 27 of the pressure limiting valve 14 to flow through the fourth fuel flow path 28 to the fuel tank 18.

[0016] It must be understood that the embodiments explained above are only illustrative and do not limit the scope of the disclosure. Many modifications in the embodiments with regard to dimensions of various components are envisaged and form a part of this invention. The scope of the invention is only limited by the scope of the claims.