GB2570644A

GB2570644A - Integrated outlet and relief valve for fuel pump

Info

Publication number: GB2570644A
Application number: GB1801098.3A
Authority: GB
Inventors: Leblay Arnaud; Aye Andreas
Original assignee: Delphi Automotive Systems Luxembourg SA
Current assignee: BorgWarner Luxembourg Automotive Systems SA
Priority date: 2018-01-23
Filing date: 2018-01-23
Publication date: 2019-08-07
Also published as: WO2019145219A1; GB201801098D0

Abstract

An integrated valves assembly 10 adapted to be arranged between a first high pressure zone Z1 (such as a common rail of a fuel injection system) and a second high pressure zone Z2 (such as a pumping chamber of a high pressure fuel pump). The assembly comprising a body 12 defining separate first 18 and second 20 fluid conduits, the first fluid conduit being controlled by a first valve 14 which may be a combined outlet check valve (OCV) and, the second fluid conduit being controlled by a second valve 16 which may be a pressure relief valve (PRV), this double-valve assembly forming an integrated cartridge. The combined OCV and PRV assembly is contained within a single housing assembly positioned between a high pressure fuel pump compression chamber and a common rail of a fuel injection system and allows a controlled flow in either direction. A high pressure fuel pump is also claimed.

Description

TECHNICAL FIELD

The present invention relates to a fuel pump wherein an outlet valve and a pressure relief valve are combined in a single cartridge.

BACKGROUND OF THE INVENTION

In a fuel injection equipment a high pressure (HP) pump delivers fuel pressurized in a pumping chamber to a high pressure reservoir, known as a common rail. The pump outlet comprises an Outlet Check Valve, hereafter OCV, and a Pressure Relief Valve, hereafter PRV. The OCV closes the pump outlet while the fuel is being pressurized in the pumping chamber and opens when the pressure surpasses a threshold and, the PRV opens during hot-soak or during testing of the fuel pump without injections to ensure that the common rail cannot be over-pressurized. The PRV and OCV are separated elements arranged within the pump body between the pumping chamber and the common rail.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to resolve the above mentioned problems in providing an integrated valves assembly adapted to be arranged in a fluid system between a first high pressure (HP) zone and a second high pressure (HP) zone. Said assembly comprises a body defining distinct first and second fluid conduits, the first fluid conduit being controlled by a first valve and, the second fluid conduit being controlled by a second valve, said doublevalve assembly forming an integrated cartridge.

Said first valve may be arranged to prevent fluid to flow from the first HP zone to the second HP zone and, said second valve is arranged to prevent fluid to flow from the second HP zone to the first HP zone.

The second valve may be arranged to enable the fluid to flow from the first HP zone to the second HP zone when the pressure in the first HP zone exceeds a first predetermined threshold and, the first valve is arranged to enable fluid to flow from second the HP zone to the first HP zone when the pressure in the second HP zone exceeds a distinct second predetermined threshold.

The first fluid conduit and the second fluid conduit may be concentric about a main axis X.

Said body may be cylindrical extending along said main axis between a first transverse end face and a second transverse end face and wherein, the body is provided with a cylindrical second recess dug in said second face and axially extending toward a bottom face proximal said first end face, the body further defining a peripheral wall surrounding said second recess.

Said second recess bottom face may define a second valve seating face surrounding the opening of the second fluid conduit, said second conduit axially extending between said opening and the first transverse face.

The body may further define a first recess centrally dug in the first transverse end face, the second fluid conduit opening in the bottom of said first recess.

The body may be further provided with at least one drilling extending between the first face and said second recess, said at least one drilling extending parallel and offset to the main axis and being arranged in the peripheral area of the body, said at least one drilling defining the first fluid conduit.

Said at least one drilling may further extends in said peripheral wall of the second recess.

Said at least one drilling may have an arcuate shape defining outer and inner faces parallel to the outer face of the body, the inner face opening in the second recess.

The body may be provided with a plurality of said drillings jointly defining said first fluid conduit.

The first valve may comprise a resilient sheet fixed to the first face, said resilient sheet being in a closed position CP against the first end face closing said first conduit when the pressure in the second HP zone is lower than said second predetermined threshold and, deflecting to an open position OP opening the first conduit when the pressure in the second HP zone exceeds said second predetermined threshold, the first end face defining a first valve seating face.

Said resilient sheet may define a peripheral annular area adapted to close said first conduit, a central area fixed to the first transverse end face and, at least one flexible arm joining the central area to the peripheral annular area.

Said flexible arm may be arcuate.

Said resilient sheet may comprise a plurality of flexible arms.

In open position of the first valve, the peripheral annular area may lift off the first transverse face and remains parallel to the central area.

The central area may be provided with a central opening defining an inner annulus surrounding the opening of the first recess.

The resilient sheet may be sandwiched in a gap defined between the first end face and a disc-like first stop member, said stop member having a disc base and a tubular turret defining a through hole. The turret protrudes from an inner face of the disc base and being engaged through said central opening of the resilient sheet and being inserted and fixed in the first recess so that the second conduit extends through the tubular turret and through the disc base, the disc base being parallel to the first end face and defining said gap G with the first end face.

In open position of the first conduit, the peripheral annular area of the resilient sheet may lie in contact against said inner face of the stop member.

The second valve may be arranged in the second recess and it comprises a spring compressed between a valve member and an adjusting plug fixed to the body, the valve member being biased against said second valve seating face closing the second conduit and, lifting from said second valve seating face in an open position OP and opening said second conduit when the pressure in said second conduit exceeds the first predetermined threshold.

The valve member may be a ball arranged in a spring seat member against which said spring exerts a closing force and wherein, the adjusting plug is screwed in the second recess and is provided with a tool engagement feature enabling complementary engagement of a tool.

Said tool engagement feature may be a female hexagon and wherein said adjusting plug is further provided with an through opening.

The compression of the spring may be predetermined by adjusting the position of the adjusting plug.

Said assembly may be arranged in a fuel injection equipment of an internal combustion engine between said first HP zone that is a common rail and said second HP zone that is the compression chamber of a fuel pump, the first valve being the outlet check valve of said pump and, the second valve being a pressure relief valve of said common rail.

Said fuel pump may define a compression chamber wherein fuel entering via a controlled inlet is pressurised by a piston reciprocating in a bore prior to be expelled, via an outlet controlled by an outlet check valve, and delivered to a common rail. Said pump further integrates a pressure relief valve enabling a return flow from the common rail to the compression chamber, said outlet valve and pressure regulating valve being arranged in an integrated valves assembly as claimed in any one of the preceding claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is now described by way of example with reference to the accompanying drawings in which:

Figure 1 is a 3D view in section of an integrated valves assembly as per the invention.

Figure 2 is a 3D view of the first end of the assembly of figure 1.

Figure 3 is a 3D view of the second end of the assembly of figure 1.

Figures 4 and 5 are detailed views of the first end of the assembly of figure 1.

Figures 6, 7 and 8 are axial sections of the assembly of figure 1 illustrating the operation of said assembly.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In reference to the figures is described an integrated valves assembly 10 comprising within a body 12 a first valve 14 and a second valve 16.

Although it has initially been developed for being arranged in a gasoline fuel direct injection (GDI) equipment of an internal combustion engine (ICE), between the compression chamber of a high pressure pump 8 and a high pressure reservoir, well known as a common rail, the invention can be utilized in many other fluid system between a first high pressure zone Z1 and a second high pressure zone Z2, the first valve 14 controlling a first fluid conduit 18 and, the second valve 16 controlling a second fluid conduit 20, said double-valve assembly forming an integrated cartridge.

In the example of a GDI equipment the first high pressure zone Z1 is the common rail and the second high pressure zone Z2 is the compression chamber. In the compression chamber the fuel is pressurized by a piston reciprocating in a bore between BDC and TDC, the first valve 14 being the outlet check valve (OCV) of the pump 8, normally closed and opening the first conduit 18 (outlet of the pump) to expel the HP fuel toward the common rail when the piston reaches TDC and, preventing fuel to return via the first conduit 18 from the common rail (first HP zone Zl) toward the compression chamber (second HP zone Z2). The second valve 16 is the pressure relief valve (PRV) normally closed and opening the second conduit 20 (return channel) to enable fluid to return via the second conduit 20 from the common rail (first HP zone Zl) to the compression chamber (second HP zone Z2) during hot-soak or during testing of the fuel pump 8 without injections to ensure that the common rail cannot be over-pressurized.

The body 12 of the example embodiment shown on the figures has a cylindrical outer face 23 extending along a main axis X between a first transverse end face 22 and a second transverse end face 24. The body 12 is provided with a first recess 26 centrally dug in the first end face 22 and also with a coaxial second recess 28 dug in the second end face 24. The first recess 26 is relatively small, having a narrow section compared to the body section and, a small depth compared to the axial length of the body. Said first recess 26 defines a cylindrical lateral face and a first bottom face. Compared to the body and to the first recess, the second recess 24 is large and deep, the body 12 defining a second bottom face 30 and a peripheral wall 32 surrounding said second recess. The second fluid conduit 20 is axially drilled between said first and second 30 bottom faces and, its opening in the second bottom face 32 is surrounded by a female conical second seating face 34.

Opposite to said second bottom face 32, the portion of the second recess 28 proximal the second end face 24 is threaded 36 to a fine pitch.

Moreover, the body 12 is provided with four drillings 18A-D defining together said first fluid conduit 18, said drilling being provided in the peripheral area of the body and extending from the first end face 22 to the second end face 24. As shown on the figures, said drillings 18A-D have a kidney shape arcuate concentric to the main axis X having a main external face parallel to the outer face of the body. In the first end face 22 of the body, said drillings 18A-D open at the bottom of an annular groove 38, said first end face 22 defining a first seating face 39 divided by the annular groove 38 in a thin external annulus 40 surrounding said groove 38 and a larger internal annulus 42 at the centre of which opens the first recess 26. Between the first end face 22 and the second end face 24, the drillings 18A-D extend in the peripheral wall 32 where they open in the second recess 28 which section consequently comprises circular portions of the recess itself alternating with larger circular portions from said drillings 18A-D, the thread 36 being provided on the circular portions of the recess only.

The example presented has four drillings 18A-D but an embodiment with more or less drillings is also possible. Similarly, the kidney shape is not mandatory and other sections are possible.

The first valve 14 (OCV) comprises a first valve member that is a resilient sheet 44, preferably metallic, covering the first end face 22 and defining a peripheral annular area 46 adapted to close said groove 38 in which opens the first conduit 18, a central area 48 fixed to the first transverse end face 22 and, two flexible arms 50 joining the central area 48 to the peripheral annular area 46.

Said arms 50 are symmetrically arranged and, in the example presented, have an arcuate U-shape extending between the central area 48 and the peripheral annular area 46. This arcuate U-shape lengthen said arms increasing their flexibility. Other number of arms and other shapes are of course possible.

The central area 48 is a disc provided with a central opening 52 and defining an inner annulus 54 surrounding the opening of the first recess 26.

A stop member 56 comprising a disc base 58 having an outer face visible on figure 2 and, an inner face 60 facing the body 12 wherefrom centrally extends a tubular turret 62 defining an inner axial through hole extending through the turret and through the disc base and opening in the outer face. In the example shown the disc base is provided with four arcuate openings limiting said disc base to a wheel-shape with radial legs connecting an internal annulus to an external annulus. Other number of openings, including none, and other shapes of openings are possible.

The stop member 56 is fixed to the body 12 as the turret 62 is engaged through the central opening 52 of the resilient member and is inserted and fixed in the first recess 26 so that the second conduit 20 extends through the tubular turret 62 and through the base. As shown the disc base is arranged parallel to the first end face 22 and, a gap G is defined between the inner face 60 of the disc base and the first end face 22, the resilient sheet 44 being sandwiched and trapped in said gap G.

The resilient sheet 44 may be fixed by known means such as welding to the body or, the stop member may be provided with a shoulder enlarging and surrounding the junction of the turret to the base, the inner annulus 54 of the resilient sheet being compressed between said shoulder and the first end face 22.

In use, the resilient sheet 44 rests in a closed position CP 14 against the first end face 22, its peripheral annular area 46 closing the annular groove 38 and the first conduit. When the pressure in the compression chamber (second HP zone Z2) sufficiently rises, it generates an opening force that flexes the arms 50 and lifts said annular area 46 off the first transverse face in an open position OP 14 wherein the annular area 46 remains parallel to the central area 48 and to the first end face. When fully open the peripheral annular area 46 is against the inner face 60 of the stop member.

The second valve 16 (PRV) is arranged in the second recess 28 and it comprises a ball 64 partially housed in a hollow of a spring seat member 66, an adjusting plug 68 complementary threaded and tightened in the threaded 36 portion of the second recess and, a spring 70 compressed between said seat member 66 and said plug 68. The ball 64 is biased against the second seating face 34 defined at the bottom of the second recess. As visible on figure 3, the adjusting plug 68 is tightened in the second recess, the four drillings 18A-D extending around the plug. Said plug is further provided with a through hole 72 joining the second HP zone Z2 to the second recess and also with a hexagonal hollow 74 defining a tool engagement feature enabling to tightened the plug and adjust the compression of the spring 70. The thread preferably has a fine pitch enabling easier tuning of said compression.

Alternatively to a female hexagon 74, the adjusting plug 68 may be provided with any feature enabling complementary engagement of a tool. This can be a slot, a cross, a male hexagon, octagon...

Said integrated valves assembly 10 defining a cartridge can easily be arranged in a single hollow provided in the body of the pump 8.

Key steps of operation are presented in figures 6, 7 and 8.

Figure 6 illustrates a rest position where the pressure in the first HP zone Zl, the common rail, is not sufficient to open the second valve 16 and, the pressure in the second HP zone Z2, the compression chamber, is not sufficient to open the first valve 14. Both valves 14, 16 are in closed position CP14, CP16. The resilient sheet 44 is against the first end face and it closes the groove 38 wherein open the drillings 18A-D defining the first conduit 18. The pressure in the first HP zone Zl pushes (arrows on figure 7) and maintains the resilient sheet 44 in said closed position. The ball 64 is urged against the second seating face closing the second conduit 20.

Figure 7 illustrates an open position of the first valve 14 OP14. The pressure in the compression chamber is raised to a level where the peripheral area 46 of the resilient sheet 44 lifts off the first end face and opens the first conduit 18 wherefrom fuel can exit toward the first HP zone Zl, as shown by the arrows of figure 7.. In said figure the second valve 16 remains in closed position CP16.

Figure 8 illustrates an open position OP 16 of the second valve 16 and a closed position CP14 of the first valve 14. The pressure in the common rail rises above a threshold and it generates on the ball 64 an opening force that push said ball and opens the second conduit 20. This situation happens during hot-soak when the ICE is stopped or during testing of the fuel pump without injections to ensure that the common rail cannot be over-pressurized.

LIST OF REFERENCES

Zl	first HP zone - common rail
Z2	second HP zone - compression chamber
BDC	bottom dead centre
TDC	top dead centre
X	main axis
G	gap
CP14	closed position of first valve
OP14	open position of the first valve

CP 16 closed position of second valve

OP 16 open position of the second valve pump integrated valves assembly body first valve - OCV second valve - PRV first fluid conduit

18A-D drillings second fluid conduit first transverse end face outer face of the body second transverse end face first recess second recess second bottom face peripheral wall second seating face thread annular groove first seating face external annulus internal annulus first valve member - resilient sheet peripheral annular area central area flexible arm central opening in the resilient sheet inner annulus stop member disc base inner face turret ball - valve member seat member adjusting plug spring hole hexagonal hollow - tool engagement feature

Claims

CLAIMS:

1. Integrated valves assembly (10) adapted to be arranged in a fluid system between a first high pressure zone (Zl) and a second high pressure zone (Z2), said assembly comprising a body (12) defining distinct first (18) and second (20) fluid conduits, the first fluid conduit being controlled by a first valve (14) and, the second fluid conduit being controlled by a second valve (20), said double-valve assembly forming an integrated cartridge.

2. Integrated valves assembly (10) as claimed in the preceding claim wherein said first valve (14) is arranged to prevent the fluid to flow from the first HP zone (Zl) to the second HP zone (Z2) and, said second valve (20) is arranged to prevent fluid to flow from the second HP zone to the first HP zone.

3. Integrated valves assembly (10) as claimed in claim 2 wherein, the second valve (20) is arranged to enable the fluid to flow from the first HP zone to the second HP zone when the pressure in the first HP zone exceeds a first predetermined threshold and, the first valve is arranged to enable fluid to flow from second the HP zone to the first HP zone when the pressure in the second HP zone exceeds a distinct second predetermined threshold.

4. Integrated valves assembly (10) as claimed in claim 3 wherein, the first fluid conduit (18) and the second fluid conduit (20) are concentric about a main axis (X).

5. Integrated valves assembly (10) as claimed in claim 4 wherein said body (12) is cylindrical extending along said main axis (X) between a first transverse end face (22) and a second transverse end face (24) and wherein, the body is provided with a cylindrical second recess (28) dug in said second face (24) and axially extending toward a bottom face (30) proximal said first end face, the body further defining a peripheral wall (32) surrounding said second recess (28).

6. Integrated valves assembly (10) as claimed in claim 5 wherein said second recess bottom face (30) defines a second valve seating face (34) surrounding the opening of the second fluid conduit (20), said second conduit axially extending between said opening and the first transverse face.

7. Integrated valves assembly (10) as claimed in claim 6 wherein the body further defines a first recess (26) centrally dug in the first transverse end face, the second fluid conduit opening in the bottom of said first recess.

8. Integrated valves assembly (10) as claimed in any one of the claims 5 to

7 wherein the body is further provided with at least one drilling (18A-D) extending between the first face and said second recess, said at least one drilling extending parallel and offset to the main axis and being arranged in the peripheral area of the body, said at least one drilling defining the first fluid conduit (18).

9. Integrated valves assembly (10) as claimed in claim 8 wherein said at least one drilling further extends in said peripheral wall (32) of the second recess.

10. Integrated valves assembly (10) as claimed in any one of the claims 8 or

9 wherein said at least one drilling has an arcuate shape defining outer and inner faces parallel to the outer face (23) of the body, the inner face opening in the second recess.

11. Integrated valves assembly (10) as claimed in any one of the claims 8 to

10 wherein the body is provided with a plurality of said drillings jointly defining said first fluid conduit (18).

12. Integrated valves assembly (10) as claimed in any one of the claims 3 to

11 wherein the first valve comprises a resilient sheet (44) fixed to the first face, said resilient sheet being in a closed position (CP 14) against the first end face closing said first conduit (18) when the pressure in the second HP zone is lower than said second predetermined threshold and, deflecting to an open position (OP 14) opening the first conduit when the pressure in the second HP zone exceeds said second predetermined threshold, the first end face defining a first valve seating face (39).

13. Integrated valves assembly (10) as claimed in claim 12 wherein said resilient sheet defines a peripheral annular area (46) adapted to close said first conduit, a central area (48) fixed to the first transverse end face and, at least one flexible arm (50) joining the central area to the peripheral annular area.

14. Integrated valves assembly (10) as claimed in claim 14 wherein said flexible arm is arcuate.

15. Integrated valves assembly (10) as claimed in any one of the claims 13 or

14 wherein said resilient sheet comprises a plurality of flexible arms.

16. Integrated valves assembly (10) as claimed in any one of the claims 13 to

15 wherein in open position (OP 14) of the first valve, the peripheral annular area (46) lifts off the first transverse face and remains parallel to the central area (48).

17. Integrated valves assembly (10) as claimed in any one of the claims 13 to

16 taken in combination with claim 7 wherein the central area (48) is provided with a central opening (52) defining an inner annulus (54) surrounding the opening of the first recess (26).

18. Integrated valves assembly (10) as claimed in claim 17 wherein the resilient sheet is sandwiched in a gap (G) defined between the first end face and a disc-like first stop member (56), said stop member having a disc base (58) and a tubular turret (62) defining a through hole, the turret protruding from an inner face (60) of the disc base, said turret being engaged through said central opening (52) of the resilient sheet and being inserted and fixed in the first recess (26) so that the second conduit (20) extends through the tubular turret and through the disc base, the disc base being parallel to the first end face and defining said gap (G) with the first end face.

19. Integrated valves assembly (10) as claimed in claim 18 wherein, in open position (OP 14) of the first conduit, the peripheral annular area (46) of the resilient sheet lies in contact against said inner face (60) of the stop member.

20. Integrated valves assembly (10) as claimed in claim 6 wherein, the second valve (16) is arranged in the second recess (28) and it comprises a spring (70) compressed between a valve member (64) and an adjusting plug (68) fixed to the body, the valve member (64) being biased against said second valve seating face (34) closing the second conduit (20) and, lifting from said second valve seating face in an open position (OP 16) and opening said second conduit when the pressure in said second conduit exceeds the first predetermined threshold.

21. Integrated valves assembly (10) as claimed in claim 20 wherein, the valve member (64) is a ball arranged in a spring seat member (66) against which said spring (70) exerts a closing force and wherein, the adjusting plug (68) is screwed in the second recess (28) and is provided with a tool engagement feature (4) enabling complementary engagement of a tool.

22. Integrated valves assembly (10) as claimed in claim 21 wherein said tool engagement feature (74) is a female hexagon and wherein said adjusting plug (68) is further provided with an through opening.

23. Integrated valves assembly (10) as claimed in any one of the claims 21 or 22 wherein the compression of the spring is predetermined by adjusting the position of the adjusting plug (68).

24. Integrated valves assembly (10) as claimed in any one of the preceding claims wherein said assembly is arranged in a fuel injection equipment of an internal combustion engine between said first HP zone (Zl) that is a common rail and said second HP zone (Z2) that is the compression chamber of a fuel pump (8), the first valve (14) being the outlet check valve (OCV) of said pump (8) and, the second valve (16) being a pressure relief valve (PRV) of said common rail.

25. High pressure fuel pump (8) of a fuel injection equipment of an internal combustion engine, said fuel pump defining a compression chamber (Z2) wherein fuel, entering via a controlled inlet, is pressurised by a piston reciprocating in a bore prior to be expelled, via an outlet controlled by an outlet check valve, and

5 delivered to a common rail, said pump further integrating a pressure relief valve enabling a return flow from the common rail to the compression chamber, said outlet valve and pressure regulating valve being arranged in an integrated valves assembly (10) as claimed in any one of the preceding claims.