WO2015183278A1

WO2015183278A1 - High-pressure pump for a fuel injection system of an internal combustion engine

Info

Publication number: WO2015183278A1
Application number: PCT/US2014/039961
Authority: WO
Inventors: Eric A. BENHAM; Kyle BREWER; David M. Rix; Thomas M. YEAGER
Original assignee: Cummins Inc.
Priority date: 2014-05-29
Filing date: 2014-05-29
Publication date: 2015-12-03

Abstract

A high-pressure fuel pump and method of assembling the same is provided. The high-pressure fuel pump includes a high-pressure fuel pump cylinder head having two fluid passage ports. Each of the ports is sized and shaped to individually receive both of a dedicated inlet valve assembly and a dedicated outlet valve assembly. The ports have identical threads configured to individually mate with threads on both the dedicated inlet valve assembly and the dedicated outlet valve assembly.

Description

HIGH-PRESSURE PUMP FOR A FUEL INJECTION SYSTEM OF AN INTERNAL

COMBUSTION ENGINE

FIELD OF THE DISCLOSURE

[0001] The present disclosure is related to high pressure pumps, providing valves thereto, and to methods of creating the same. The present disclosure is more specifically directed to high pressure pumps having interchangeable inlet and outlet locations and to methods of creating the same.

BACKGROUND

[0002] Today's engine designers must meet the challenge of government mandated emissions criteria while striving to improve engine fuel efficiency. In rising to this challenge, designers create fuel systems that operate at higher pressures than systems of the past (over 1,000 bar). To obtain such high fuel pressure, a high-pressure fuel pump is generally provided on the side of an engine in addition to a low-pressure fuel pump provided operatively between the high- pressure pump and the fuel source (such as a tank). In general, the low-pressure fuel pump is driven by, for example, the high-pressure pump, while the high-pressure fuel pump is driven by an engine and it runs as the engine runs.

BRIEF DESCRIPTION OF THE DRAWINGS

[0003] FIG. 1 is a side plan view of a high-pressure cylinder head of a high-pressure fuel pump according to an exemplary embodiment of the present disclosure where certain internal features are shown in phantom;

[0004] FIG. 2 is a cross-sectional view of the exemplary high-pressure cylinder head of

Fig. 1; [0005] FIG. 3 is a cross-sectional view of the cylinder head of Fig. 1 having inlet and outlet assemblies coupled thereto in a side-out configuration;

[0006] FIG. 4 is a cross-sectional view of the cylinder head of Fig. 1 having inlet and outlet assemblies coupled thereto in a top-out configuration; and

[0007] FIG. 5 is a flow-chart showing exemplary operation of an assembly line utilizing the high-pressure pump of Figs. 1-4.

DETAILED DESCRIPTION

[0008] Briefly, in one example, a high-pressure fuel pump is provided. The high- pressure fuel pump includes a high-pressure fuel pump cylinder head having two fluid passage ports. Each of the ports is sized and shaped to individually receive both of a dedicated inlet valve assembly and a dedicated outlet valve assembly. The ports have identical threads configured to individually mate with threads on both the dedicated inlet valve assembly and the dedicated outlet valve assembly.

[0009] In another example, a method of operating a high-pressure fuel pump assembly line is provided including: obtaining a plurality of identical fuel pump cylinder heads, including first and second fuel pump cylinder heads, each having a plurality of fluid ports including a first port and a second port; placing an inlet valve in the first port of a first fuel pump cylinder head, and placing an outlet valve in the second port of the first fuel pump cylinder head, such valve placement creating a top-outlet high pressure fuel pump; and placing an outlet valve in the first port of a second fuel pump cylinder head, and placing an inlet valve in the second port of the second fuel pump cylinder head, such valve placement creating a side-outlet high pressure fuel pump. [0010] In yet another example, a fluid pump is provided including a cylinder head. The cylinder head including two fluid passage ports, each of the ports sized and shaped to individually receive both of a dedicated inlet valve assembly and a dedicated outlet valve assembly.

[0011] In another exemplary embodiment, a set of valve assemblies for a fluid pump is provided including: an inlet valve assembly defining a sealing profile operable to seal the inlet valve assembly to a first port of a cylinder head; and an outlet valve assembly defining a sealing profile operable to seal the outlet valve assembly to the first port of the cylinder head.

[0012] As fuel pressures are increased (sometimes to excess of 2600 bar), part interfaces and seals used in fuel pressurization systems must also be able to withstand and maintain such pressures. Accordingly, parts of such systems are required to have specifically crafted specialized interfaces and tight tolerances in sizing. Each increase in pressure provides increased potential for failure and increased cost to contain and maintain that pressure.

[0013] Current unit barrel technology in inline fuel pumps utilizes either "top-out" or

"side-out" configurations. The use of one or there other is often dictated by the configuration of the engine that the pump is supplying and the location where the pump is to be relative to the engine. Accordingly, pump cylinder heads are created (such as by machining and/or casting) to provide such top-out or side-out functionality. Separate inventories of parts for top-out and side- out pumps need to be created and maintained for use in a manufacturing line to allow each to be produced thereby.

[0014] Cylinder heads have been developed where multiple potential outlet locations are provided such that assembly can choose one or the other to result in a top-out or side -out configuration. In such cylinder heads, the unused outlet location is typically "plugged" or "capped." It should be appreciated that this capping location and cap provide another interface point of potential failure. Such potential failure is exacerbated by the high pressure environment.

[0015] Turning now to the drawings wherein like numerals represent like components,

FIG. 1 is a view of exemplary high pressure cylinder head 20 of high-pressure fuel pump element 10 shown in Fig. 3. High-pressure fuel pump element 10 is illustratively of the type used in a high pressure pump in a high-pressure fuel injection system.

[0016] Such high pressure fuel injection systems typically utilize at least one high pressure pump element that pressurizes the fuel to be injected by fuel injectors (not shown). Fuel systems may utilize a plurality of such pressure pumps corresponding to the number of fuel injectors (and/or cylinders of the engine), each of the pumps providing highly pressurized fuel to a fuel injector. Other fuel systems utilize fewer high pressure pumps in conjunction with a high pressure common rail (not shown). In such implementations, one or more high pressure pumps are connected to the high pressure common rail to thereby provide highly pressurized fuel to the common rail. The common rail then distributes the pressurized fuel to each of the fuel injectors.

[0017] Pump element 10 generally includes cylinder head assembly 12, inlet valve assembly 14, and outlet valve assembly 16. Cylinder head assembly 12 illustratively includes cylinder head 20, piston 22, spring 24, and retractor 26.

[0018] Cylinder head 20, shown in Figs. 1 and 2, includes top threaded valve bore 28, side threaded valve bore 30, piston bore 32, spring seat 34, internal fuel passageways 36, and side bore conduit 37. Top threaded valve bore 28 and side threaded valve bore 30 are illustratively identically dimensioned and have identical threading defined on their inner walls. The identical dimensions provide that the bores 28, 30 have identical sealing profiles. Bores 28, 30 are illustratively fluid passage ports. Top threaded valve bore 28 has a longitudinal axis 38 that is parallel with, and in the exemplary embodiment, co-linear with a longitudinal axis of piston bore 32. A lower end of top threaded valve bore 28 interfaces with piston bore 32 such that fluid can flow therebetween. Different portions of the inner walls of top and side threaded valve bores 28, 30 provide different sealing surfaces, depending upon the particular valve assembly received therein. Such sealing surfaces and their interaction with valve assemblies is discussed further below.

[0019] Side threaded valve bore 30 has a longitudinal axis 40 that is illustratively perpendicular to longitudinal axis 38 of top threaded valve bore 28. A lower end of side threaded valve bore 30 interfaces with side bore conduit 37. Side bore conduit 37 interfaces with piston bore 32 such that fluid can flow side threaded valve bore 30 and piston bore 32.

[0020] Both top threaded valve bore 28 and side threaded valve bore 30 are further able to fluidly communicate with internal fuel passageways 36, Fig. 1. A first internal fuel passageway 36 extends from a fuel input 42a (generally proximate fuel input area 42) to side threaded valve bore 30. Fuel input 42a is generally in communication with a source of fuel, such as via a low power fuel pump (not shown). A second internal fuel passageway 36a links side threaded valve bore 30 and top threaded valve bore 28. Low pressure fuel is there by supplied to and urged through fuel passageways 36 to side threaded valve bore 30 and top threaded valve bore 28. Additional internal passageways 36b extend from fuel input area 42 to piston bore 32. Passageways 36b allow for drainage of fuel. Passageways 36b return left fuel to piston bore 32.

[0021] Piston bore 32 is sized to receive piston 22 therein. Piston 22 and piston bore are generally sized to minimize liquid that can pass therebetween while not providing such a snug fit that excessive heat is produced from the relative motion of piston 22 and piston bore 32. [0022] Spring seat 34 is proximate a lower end of cylinder head 20 and is sized to receive and provide a support surface against which spring 24 can exert force. Spring seat 34 is a shoulder formed at the transition point of different diameters of cylinder head 20. Spring 24 is a coil spring that sits on spring seat 34 such that the lower portion 46 of cylinder head 20 is received within the center of the spring. Lower portion 46 further provides a centering function that prevents substantial radial travel of spring 24 relative to cylinder head 20.

[0023] A lower end of piston 22 is coupled to retractor 26. Retractor 26 includes spring seat 48 and piston receiver 50. Similar to spring seat 34, spring seat 48 is sized to receive and provide a support surface against which spring 24 can exert force. Spring seat 48 is a shoulder formed at a lower end of retractor 26. Retractor 26 further includes a lower surface 52 upon which force is exerted by another element. Piston receiver 50 securely couples retractor 26 to piston 22 such that vertical motion (along axis 38) of piston 22 and of retractor 26 are linked.

[0024] In assembly, spring 24 is positioned between spring seat 34 and spring seat 48 to resist upward forces exerted on retractor 26 (such as those, indirectly, from a cam). Accordingly, upward forces exerted on retractor 26 that are able to overcome the force exerted by spring 24 cause upward movement of retractor 26 and piston 22 that compress spring 24. When such upward forces are removed or reduced, energy stored in compressed spring 24 then urges retractor 26 and piston 22 downward to de-compress spring 24. In such fashion, a cyclic force applied to retractor 26 results in a reciprocating movement of piston 22.

[0025] Inlet valve assembly 14 is illustratively a dedicated inlet valve assembly in that it can only function as an inlet valve rather than a reversible valve. Inlet valve assembly 14 illustratively includes seat 54 and threaded plug 62. Seat 54 includes plunger 56, retainer 58, spring 60, and seat body 70. Seat body 70 includes plunger bore 64, fuel passage(s) 66, seat seals 68. Plunger 56 is received in plunger bore 64. Plunger 56 is retained in seat body 70 by retainer 58. Plunger 56 is further biased towards a closed (retracted) position by spring 60 that urges retainer 58 away from seat body 70. Seat seals 68 are portions of seat body 70 that are sized, shaped, and positioned to abut portions of a valve bore (28, 30) to create a seal therewith to prevent (or at least severely minimize) passage of fluid between seat 54 and valve bore (28, 30). Seat seals 68 contribute to a sealing profile between inlet valve assembly and a valve bore 28, 30 that receives it. Fuel passages 66 provide conduit for fuel provided to valve bore (28, 30) at a location outside of seat 54 to be directed to plunger bore 64 "behind" a head of plunger 56. Accordingly, if fuel is provided to valve bore (28, 30) at such a pressure that overcomes forces of spring 60 and any opposing forces within piston bore 32 (or with the aid of forces within piston bore 32), such pressures will cause movement of plunger 56 and allow fuel to pass through seat 54 into piston bore 32.

[0026] Threaded plug 62 includes an inner bore 72 sized, shaped, and positioned to receive and provide clearance for plunger 56, retainer 58, and spring 60. Threaded plug 62 further includes a threaded outer circumference including seal 74. In the present example, inlet valve assembly 14 is disclosed as having separable seat body 70 and threaded plug 62. However, it should be appreciated that embodiments of inlet valve assembly 14 (and outlet valve assembly) having a single body that contains the parts described herein (or variations thereof) are envisioned. In the present example, the outer surface of threaded plug 62 includes areas of differing diameters that are matched by areas within valve bores 28, 30.

[0027] In assembly, seat 54 (with plunger 56, retainer 58, and spring 60) is placed within valve bore (28, 30) such that seat seals 68 abut walls of valve bore (28, 30). Such placement results in plunger 56 being aligned along the longitudinal axis (38, 40) of the valve bore (28, 30) in which it is received. Then, threaded plug 62 is threadably engaged to valve bore (28, 30). Such engagement causes a lower surface of threaded plug 62 to abut seat 54. Further advancement of threaded plug 62 after abutment with seat 54 serves to further press seat 54 (and seat seals 68) into abutment with valve bore (28, 30). In such a manner, inlet valve assembly 14 is secured within valve bore (28, 30) so as to properly seal therebetween to sustain and contain high pressures. It should be appreciated that due to the fact that both valve bores (28, 30) are identically sized and shaped, inlet valve assembly 14 is readily received in either valve bore (28, 30) as desired.

[0028] Outlet valve assembly 16 is illustratively a dedicated outlet valve assembly in that it can only function as an outlet valve rather than a reversible valve. Outlet valve assembly 16 illustratively includes outlet threaded body 75, outlet seat body 76, plunger 78, and spring 82. Outlet threaded body 75 includes threaded outer surface 84 and internal fluid passage 86. Outlet valve assembly 16 is illustratively shown as a multi-part body (outlet threaded body 75 and outlet seat body 76). It should be appreciated that embodiments are envisioned where the body is constructed from a single part. Outer surface 84 includes a portion sized and shaped to be received within valve bores (28, 30). Internal fluid passage 86 includes spring retainer portion 80. Spring retainer portion 80 receives and provides a support surface for spring 82.

[0029] Outlet seat body 76 includes sealing surfaces 88 sized, shaped, and positioned to abut portions of valve bore (28, 30) to create a seal therewith to prevent (or at least severely minimize) passage of fluid between outlet seat body 76 and valve bore (28, 30). Sealing surfaces 88 contribute to a sealing profile between outlet valve assembly 16 and a valve bore 28, 30 that receives it. Similar to the operation of inlet valve assembly 14, once sealing surfaces 88 abut valve bore (28, 30) further advancement of outlet threaded body 75 (via tightening against threads of valve bore 28, 30) serves to press sealing surfaces 88 into sealing engagement with valve bore (28, 30). Overall, outlet valve assembly 16 provides a different contour and sealing profile than that provided by inlet valve assembly 14. However, valve bores (28, 30) are sized and shaped such that threaded engagement of either of inlet or outlet assemblies 14, 16 provide for sealing the assemblies 14, 16 to valve bores (28, 30).

[0030] Plunger 78 and spring 82 are at least partially disposed within fluid passage 86 and cooperate to provide a one-way (outlet) valve. Outlet seat body 76 includes fluid passage 90. Plunger 78 is able to move within fluid passages 90, 86. Spring 82 presses against retainer portion 80 and urges plunger 78 away from threaded body 75. With spring 82 extended, plunger 78 seats against a portion of fluid passage 86 such that fluid flow therein is arrested. When the pressure within piston bore 32 is greater than the force exerted by spring 82 (and any pressure in internal fluid passage 86), plunger 78 is moved such that fluid flow is permitted within fluid passage.

[0031] In that valve bores 28, 30 are identically sized, and in that inlet and outlet valve assemblies 14, 16 are sized and shaped to threadably engage and seal to valve bores 28, 30, the present disclosure provides a system by which a fuel supply high pressure pump element 10 is readily interchangeable as a top-out or side-out pump. This functionality is further provided without extraneous ports that need to be plugged by a non-valve plug. Placement of inlet valve assembly 14 and outlet valve assembly 16 in cylinder head 20 results in filling all ports capable of receiving an inlet or outlet valve assembly 14, 16. Furthermore, there is nothing in valve bores 28, 30 that makes or requires that bore to be either of an inlet or outlet bore. Rather, the bore's function as an inlet or an outlet is fully controlled by the valve assembly received therein. [0032] For assembly, an assembly line can be provided with a plurality of cylinder heads

20, a plurality of inlet valve assemblies 14 and a plurality of outlet valve assemblies 16. With these three types of components, the line is prepared to assemble a top-out pump followed by a side -out pump without any difference in the components used for each pump. As an exemplary illustration, an assembly line is stocked via obtaining a plurality of identical fuel pump cylinder heads 20 each having a plurality of fluid ports including a first port 30 and a second port 28 (block 500). Assembly of a first pump element 10 is performed by placing inlet valve assembly 14 in the first port 30 of a first fuel pump cylinder head 20, and placing outlet valve assembly 16 in the second port 28 of the first fuel pump cylinder head 20, such valve placement creating a top-outlet high pressure fuel pump (Fig. 4), block 520. Assembly of a second pump element 10 is performed by placing outlet valve assembly 16 in the first port 30 of a second fuel pump cylinder head 20, and placing an inlet valve assembly 14 in the second port 28 of the second fuel pump cylinder head 20 to create a side-outlet high pressure fuel pump, Fig. 3, block 540.

[0033] Once assembled, pump element 10 operates in a traditional manner as the reciprocating motion of piston 22 causes the intake and outflow of fuel through pump element 10 to provide a high-pressure fuel flow.

[0034] The above detailed description and the examples described therein have been presented for the purposes of illustration and description only and not for limitation. For example, the operations described may be done in any suitable manner. The method steps may be done in any suitable order still providing the described operation and results. It is therefore contemplated that the present embodiments cover any and all modifications, variations or equivalents that fall within the spirit and scope of the basic underlying principles disclosed above and claimed herein.

Claims

WHAT IS CLAIMED IS:

1. A high-pressure fuel pump including:

a high-pressure fuel pump cylinder head, the cylinder head including two fluid passage ports, each of the ports sized and shaped to individually receive both of a dedicated inlet valve assembly and a dedicated outlet valve assembly, the ports having identical threads defined therein and configured to individually mate with threads on both the dedicated inlet valve assembly and the dedicated outlet valve assembly.

2. The pump of claim 1, wherein both ports have identical seal profiles configured to mate with housings of both the dedicated inlet valve assembly and the dedicated outlet valve assembly.

3. The pump of claim 1, wherein both ports are configured to operate as inlets when the dedicated inlet valve assembly is received therein.

4. The pump of claim 1, wherein both ports are configured to operate as outlets when the dedicated outlet valve assembly is received therein.

5. The pump of claim 1, wherein the two fluid passage ports each have a central axis, the central axes being perpendicular to each other.

6. The pump of claim 1, further including an inlet valve assembly defining a sealing profile operable to seal the inlet valve assembly to a first port of the cylinder head; and an outlet valve assembly defining a sealing profile operable to seal the outlet valve assembly to the first port of the cylinder head.

7. A method of operating a high-pressure fuel pump assembly line including:

obtaining a plurality of identical fuel pump cylinder heads, including first and second fuel pump cylinder heads, each having a plurality of fluid ports including a first port and a second port;

placing an inlet valve in the first port of a first fuel pump cylinder head, and placing an outlet valve in the second port of the first fuel pump cylinder head, such valve placement creating a top-outlet high pressure fuel pump; and placing an outlet valve in the first port of a second fuel pump cylinder head, and placing an inlet valve in the second port of the second fuel pump cylinder head, such valve placement creating a side -outlet high pressure fuel pump.

8. The method of claim 7, wherein placement of the inlet valve and outlet valve in the first fuel pump cylinder head results in filling all ports sized to receive an outlet valve.

9. The method of claim 7, wherein the first and second ports are the only ports in the first cylinder head are the only ports in the first cylinder head sized and threaded to receive an outlet valve.

10. A fluid pump including:

a cylinder head, the cylinder head including two fluid passage ports, each of the ports sized and shaped to individually receive both of a dedicated inlet valve assembly and a dedicated outlet valve assembly.

11. The pump of claim 10, wherein the pump is a fuel pump.

12. The pump of claim 10, wherein both ports have identical threads configured to mate with threads on both the dedicated inlet valve assembly and the dedicated outlet valve assembly.

13. The pump of claim 10, wherein both ports have identical seal profiles configured to mate with housings of both the dedicated inlet valve assembly and the dedicated outlet valve assembly.

14. The pump of claim 10, wherein both ports are configured to operate as inlets when the dedicated inlet valve assembly is received therein.

15. The pump of claim 10, wherein both ports are configured to operate as outlets when the dedicated outlet valve assembly is received therein.

16. The pump of claim 10, wherein the two fluid passage ports each have a central axis, the central axes being perpendicular to each other.

17. The pump of claim 10, wherein the inlet valve assembly and outlet valve assembly define different sealing profiles for sealing the valve assemblies to the cylinder head.

18. The pump of claim 10, further including an inlet valve assembly defining a sealing

profile operable to seal the inlet valve assembly to a first port of the cylinder head; and an outlet valve assembly defining a sealing profile operable to seal the outlet valve assembly to the first port of the cylinder head.

19. A set of valve assemblies for a fluid pump including:

an inlet valve assembly defining a sealing profile operable to seal the inlet valve assembly to a first port of a cylinder head; and

an outlet valve assembly defining a sealing profile operable to seal the outlet valve assembly to the first port of the cylinder head.

20. The set of valve assemblies of claim 19, wherein the sealing profile of the inlet valve assembly is different than the sealing profile of the outlet valve assembly.

21. The set of valve assemblies of claim 19, wherein the fluid pump is a high pressure pump.

22. The set of valve assemblies of claim 19, wherein both valve assemblies have identical threads configured to mate with threads on a plurality of ports in a cylinder head.

23. The set of valve assemblies of claim 19, wherein coupling the inlet valve assembly to a port in a cylinder head makes the port an inlet port.