Pump drive cartridge assembly

Abstract

An anti-rotation sleeve for a high-pressure piston compression pump includes a sleeve having a generally cylindrical elongated shape and extending longitudinally along a central axis from a first end to a second end and features that provide orientation and that limit radial movement integrated in an inner diameter of the sleeve. The first end of the sleeve attaches to a base of the pump and the second end slidably engages a lifter body. The lifter body includes corresponding features that provide orientation and that limit radial movement integrated in an outer diameter of the lifter body. By providing an anti-rotation sleeve a relatively simple pump drive cartridge assembly that integrates all pump drive components into a one integral part is enabled. Hence, lower manufacturing and assembly costs, reduced manufacturing and assembly cycle times, and easier packaging conditions are obtained.

Description

TECHNICAL FIELD

The present invention relates to direct injection internal combustion engines; more particularly, to high-pressure mechanical fuel pumps used in high-pressure direct injection fuel systems; and most particularly, to a pump drive cartridge assembly.

BACKGROUND OF THE INVENTION

It has become generally known in the art of internal combustion engine design to use high-pressure mechanical fuel pumps in direct injection fuel systems. In known direct injection fuel systems, a high-pressure fuel injection pump typically disposed in the engine compartment close to the injector fuel rail is arranged to supply fuel from a pumping chamber to associated injectors located downstream of the pumping chamber.

Traditionally, high-pressure mechanical fuel pumps require a camshaft follower, such as a flat foot follower or a roller follower, operated by a dedicated camshaft lobe on a rotating jack shaft, to transmit the rotational motion and lift of the camshaft lobe to a linear motion required to drive a typical piston compression pump. A high-pressure fuel pump may generate fuel system pressure approaching 100 atmospheres or more.

These high fuel pressures generate high loads in the system and require a robust pump and pump drive design. Based on the design of the internal combustion engine and/or the pump placement, the assembly of the pump and lifter assembly becomes cumbersome and costly, especially when roller followers are used, and alignment of the roller follower and a camshaft is required.

Typically, a lifter engages a camshaft lobe via the camshaft follower end, which preferably includes a roller. Unless suitably constrained by an anti-rotation guide, a roller follower lifter may rotate axially in its bore during reciprocation, thereby undesirably misaligning its roller follower from the associated camshaft lobe.

Lifter anti-rotation guides in the prior art are often integrated in the engine block adjacent to the lifter bore. A locating feature in the guide aperture, such as a longitudinal groove or undercut, receives a mating feature in the lifter to prevent the lifter from rotating about its longitudinal axis during reciprocation. Machining of such locating features is cost and labor intensive. Other prior art lifter anti-rotation guides utilize secondary anti-rotation attachments of locator features that are attached to the engine following lifter installation and, therefore, add another step to the assembly process.

What is needed in the art is to simplify the assembly process of a high-pressure direct injection fuel system and to reduce the total number of parts of such system.

It is a principal object of the present invention to provide a cartridge assembly that integrates all pump drive components in one integral part.

It is a further object of the invention to simplify engine block machining by eliminating secondary anti-rotation attachments or locator features.

SUMMARY OF THE INVENTION

The present invention successfully addresses the shortcomings of the prior art by providing in a first aspect of the invention a cartridge pump drive assembly that includes an anti-rotation sleeve and that integrates all pump drive components in one integral part.

The anti-rotation sleeve extends from the base of a high-pressure pump, around a reciprocating plunger and spring assembly, over a push rod assembly (if one is required for driving the pump), and to a lifter body above a lifter engine bore. The inner pump shaft may be extended as needed or a simple lower cost push rod may be used to connect the pump plunger to the lifter body as needed). The anti-rotation sleeve engages an end of the lifter body but is designed to allow the lifter body to slide up and down within the anti-rotation sleeve based on the drive motion created by a camshaft lobe profile thereby transmitting the vertical reciprocating motion to the pump. The sleeve may be made out of a lightweight polymer or drawn from thin sheet steel and may be designed to minimize the reciprocating weight and to reduce engine friction. The anti-rotation sleeve may be designed to allow additional spring packaging to support the lifter body and push rod reciprocating mass.

All drive components are self-contained within the anti-rotation sleeve thereby resisting separation during shipping or assembly. A simple press/snap fit or other engagement technique may be used at the pump end and a captive ring, snap fit or other engagement technique may be used at the sliding end. If a roller lifter is used and anti-rotation is required, the sleeve can be pinned or retained to the upper pump body and undercuts can be provided on the top of the lifter body or a sliding pin device can be utilized.

By using the anti-rotation sleeve in accordance with the invention, a relatively simple single piece cartridge assembly is provided utilizing relatively low cost modifications. The pump drive cartridge assembly in accordance with the invention minimizes engine assembly steps, total number of parts, and installation time. Existing manufacturing and assembly techniques can be used to implement the anti-rotation sleeve in accordance with the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

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

FIG. 1 is a cross-sectional view of a pump assembly, in accordance with a first embodiment of the invention;

FIG. 2 is a cross-sectional view taken along line 2-2 in FIG. 1, in accordance with the first embodiment of the invention;

FIG. 3 is a cross-sectional view taken along line 3-3 in FIG. 2, in accordance with the first embodiment of the invention;

FIG. 4 is a cross-sectional view taken along line 4-4 in FIG. 2, in accordance with the first embodiment of the invention; and

FIG. 5 is a cross-sectional view of a pump assembly, in accordance with a second embodiment of the invention.

Corresponding reference characters indicate corresponding parts throughout the several views. The exemplification set out herein illustrates preferred embodiments of the invention, in one form, and such exemplification is not to be construed as limiting the scope of the invention in any manner.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIG. 1, a pump assembly 100 includes a high-pressure pump 110, a camshaft lobe 120, and a pump drive cartridge assembly 130 arranged between pump 110 and lobe 120. The pump drive cartridge assembly 130 includes an anti-rotation sleeve 132 that extends from a base 112 of high-pressure pump 110 to a lifter body 134 above an engine lifter bore 114. Cartridge assembly 130 houses a reciprocating plunger 136 and spring 138 assembly, and extends partially over a push rod 142. Lifter body 134 engages camshaft lobe 120 via a camshaft follower, for example, a roller follower 144 as shown in FIG. 1 that is attached to one end of lifter body 134. Roller follower 144 transmits the rotational motion and lift of camshaft lobe 120 to a linear vertical motion of lifter body 134 required to drive pump 110, which may be a typical high-pressure piston compression pump. Pump assembly 100 is suitable for various engine-mounting applications and may be installed to an engine block 116 through an engine interface, for example, through an oil manifold assembly plate 118 or a suitable bracket.

Lifter body 134 includes a push rod seat 146 that receives push rod 142. Push rod 142 extends between lifter body 134 and plunger 136 to transmit the linear vertical reciprocating motion of lifter body 134 to plunger 136 of pump 110. While push rod 142 is shown to have parallel axial extending walls, it may be possible to use a tapered push rod that includes a larger diameter inserted in lifter body 134 and that includes a smaller diameter at the pump side. It may also be possible to utilize a push rod 142 that is crowned at the end where it contacts plunger 136.

Lifter body 134 has a generally cylindrical elongated shape. Lifter body 134 has roller follower 144 attached at one end and receives push rod 142 through an open opposite end. The open end of lifter body 134 is received by and slidably attached to sleeve 132. Lifter body 134 may include openings 135 as oil passages that enable oil drainage and adequate lubrication of the roller follower 144/camshaft lobe 120 interface. Shown in FIG. 1 is a lifter body 134 that extends longitudinally along axis 140 for a relatively long distance.

Anti-rotation sleeve 132 has a generally cylindrical elongated shape and extends longitudinally along a central axis 140 from a first end 148 to a second end 152. First end 148 is designed to be received by base 112 of pump 110. Sleeve 132 may be attached to base 112 of pump 110 by a typical engagement technique; for example, by a simple press/snap fit or crimp fit mechanism. If roller follower 144 is used as shown in FIG. 1 and anti-rotation is required, sleeve 132 may be pinned or otherwise retained to base 112 of pump 110 to keep roller 144 properly aligned with its mating camshaft lobe. Second end 152 of sleeve 132 is designed to receive and engage lifter body 134 such that lifter body 134 is able to slide up and down within sleeve 132 based on the drive motion created by the profile of camshaft lobe 120. Therefore the inner diameter of sleeve 132 at second end 152 is designed to receive the outer diameter of lifter body 134. When inserted, lifter body 134 and sleeve 132 overlap in axial direction for a distance. Sleeve 132 may be attached to lifter body 134 by an engagement technique, such as a captive ring or a press/snap fit mechanism. In accordance with the invention, it is also possible that the sleeve and body be designed so that an outer diameter of sleeve 132 receives an inner diameter of lifter body 132. If roller follower 144 is used as shown in FIG. 1 and anti-rotation is required, undercuts may be provided on the top of lifter body 134 as illustrated in FIGS. 2-4 or a sliding pin device may be utilized as in traditional valve train roller lifter systems.

Anti-rotation sleeve 132 may be formed from a relatively light weight polymer material or steel and may be designed with several holes 154 as oil passages incorporated that allow splash lubrication into and out of pump drive cartridge assembly 130 to minimize the reciprocating weight of assembly 130 while enabling adequate lubrication of the interfaces of pump assembly 100. The axial length of sleeve 132 can be adjusted to various engine mounting requirements.

All pump drive components, such as plunger 136 and spring 138 assembly, push rod 142, lifter body 134, and camshaft follower, for example, a roller follower 144 as shown in FIG. 1, are self contained within anti-rotation sleeve 132, such that these parts cannot become separated during shipping or during assembly. Sleeve 132 may be attached to pump 110 prior to shipping and/or prior to assembly into engine lifter bore 114, such that pump assembly 100 is shipped and/or installed as a single integral part.

Referring to FIGS. 2 through 4, cross-sectional views are taken in various directions where lifter body 134 and anti-rotation sleeve 132 overlap. In this overlapping area, several features that provide orientation and that prevent radial movement of lifter body 134 relative to anti-rotation sleeve 132 may be included. As illustrated in FIGS. 2 and 3, both lifter body 134 and anti-rotation sleeve 132 may have corresponding flat surfaces 156 and 158, respectively, incorporated. Flat surface 156 and 158 are positioned where anti-rotation sleeve 132 engages lifter body 134 and prevent axial rotation of lifter body 134 relative to anti-rotation sleeve 132. Flat surface 156 and 158 are also orientation guides that simplify the assembly process of pump assembly 100. Tolerances between the two flat surfaces 156 and 158 and length of the two flat surfaces 156 and 158 are dimensioned to allow axial movement of lifter body 134 within anti-rotation sleeve 132. As shown in FIG. 2, a pair of flat surfaces 156 positioned across from each other and a pair of flat surfaces 158 may be formed in lifter body 134 and anti-rotation sleeve 132, respectively. To further limit the axial position possibilities of the body relative to the sleeve, it may also be possible to form only one flat surface 156 and only one corresponding flat surface 158 in lifter body 134 and anti-rotation sleeve 132, respectively. Flat surface 156 of lifter body 134 may be formed as an undercut as illustrated in FIG. 3.

Referring to FIG. 4, in addition to flat surfaces 156 and 158, a pair of sliding pin features 160 may be included as anti-rotation feature in pump drive cartridge assembly 130. Sliding pin features 160 are positioned perpendicular to flat surfaces 156 and 158. It may be possible to include only one sliding pin feature 160 to prevent axial rotation of lifter body 134 relative to sleeve 132. It may further be possible to include only sliding pin features 160 and not flat surfaces 156 and 158.

Sliding pin feature 160 may include a projection 162, such as a pin, formed to extend from the inner diameter of sleeve 132 and a groove 164 formed in the outer diameter of lifter body 134 receiving the projection 162. Projection 162 and groove 164 are dimensioned such that projection 162 is able to slide axially up and down within groove 164 based on the drive motion created by the profile of camshaft lobe 120 shown in FIG. 1. Groove 164 limits the radial movement of projection 162, and therefore the radial movement of the body relative to the sleeve. Furthermore, projection 162 and groove 164 are designed such that lifter body 134 can be connected with sleeve 132 by a press/snap fit technique.

Referring now to FIG. 5, a pump assembly 200 includes a high-pressure pump 210, a camshaft lobe 220, and a pump drive cartridge assembly 230 arranged between pump 210 and lobe 220. The pump drive cartridge assembly 230 includes an anti-rotation sleeve 232 that extends from a base 212 of high-pressure pump 210 to a lifter body 234 above an engine lifter bore 214, and houses a reciprocating plunger 236 and spring 238 assembly. Contrary to pump assembly 100 shown in FIG. 1, pump assembly 200 does not include a push rod, such as push rod 142, and plunger 236 directly contacts roller follower 244. Lifter body 234 engages camshaft lobe 220 via a camshaft follower, for example, a roller follower 244 as shown in FIG. 5 that is attached to one end of lifter body 234. Roller follower 244 transmits the rotational motion and lift of a camshaft lobe to a linear motion of lifter body 234 required to drive pump 210, which may be a typical high-pressure piston pump. Pump assembly 200 is suitable for various engine-mounting applications and may be installed to an engine block 216 through an engine interface, for example, through an oil manifold assembly plate 218 or a suitable bracket.

Lifter body 234 has a generally cylindrical elongated shape. Lifter body 234 has roller follower 244 attached at one end and receives plunger 236 through an opposite open end. The open end of lifter body 234 is received by and slidably attached to sleeve 232. Lifter body 234 may include openings 235 that enable oil drainage. A c-clip 266 or other attachment feature attaches lifter body 234 to plunger 236. The attachment feature can be used to transmit the vertical reciprocating motion of lifter body 234 to pump 210. Shown in FIG. 5 is a lifter body 234 that extends longitudinally along axis 240 for a relatively long distance.

Anti-rotation sleeve 232 may be designed similar to anti-rotation sleeve 132 shown in FIG. 1 and may connect pump 210 and lifter body 234. Anti-rotation sleeve 232 may engage lifter body 234 including features providing orientation and anti-rotation similar to anti-rotation sleeve 132 as shown in FIGS. 2-4.

The axial length of anti-rotation sleeves 132 and 232 shown in FIGS. 1 and 2, respectively, may be adapted according to the industry and customer needs. The axial length of lifter bodies 134 and 234 shown in FIGS. 1 and 2, respectively, may also be adapted according to the industry and customer needs. Accordingly, a design of pump assembly 200 is possible, where sleeve 232 has a larger diameter and a shorter axial length than illustrated in FIG. 5 to accommodate a spring 238 that is wider and shorter. Such sleeve 232 may engage a lifter body 234 that has a shorter axial length than shown in FIG. 5.

By providing an anti-rotation sleeve, such as sleeves 132 and 232 shown in FIGS. 1 and 5, respectively, a relatively simple pump drive cartridge assembly, such as assemblies 130 and 230 shown in FIGS. 1 and 5, respectively, that integrates all pump drive components into a one integral part is enabled. Hence, lower manufacturing and assembly costs, reduced manufacturing and assembly cycle times, and easier packaging conditions are obtained.

While the invention has been described by reference to various specific embodiments, it should be understood that numerous changes may be made within the spirit and scope of the inventive concepts described. Accordingly, it is intended that the invention not be limited to the described embodiments, but will have full scope defined by the language of the following claims.

Claims

1. An anti-rotation sleeve for a fuel pump, comprising:

a sleeve having a generally cylindrical elongated shape and extending longitudinally along a central axis from a first end to a second end; and

at least one feature that provides orientation and that limits radial movement integrated in said sleeve;

wherein said first end of the sleeve attaches to a base of said fuel pump;

wherein said second end of the sleeve slidably engages a lifter body; and

wherein said lifter body includes at least one feature that mates with said at least one sleeve feature to provide orientation and to limit radial movement of said lifter body relative to said sleeve.

2. The anti-rotation sleeve of claim 1, wherein said at least one sleeve feature includes one of a flat surface or a projection; and wherein said at least one lifter body feature includes the other of said flat surface or said projection, thereby limiting radial movement of said lifter body relative to said sleeve.

3. The anti-rotation sleeve of claim 1, wherein said sleeve houses a reciprocating plunger and spring assembly of said pump.

4. The anti-rotation sleeve of claim 1, wherein said first end is retained to said base of said pump such that radial movement of said sleeve relative to said base is prevented.

5. The anti-rotation sleeve of claim 1, further comprising a plurality of holes incorporated in said sleeve, wherein said holes enable oil passage into and out of said sleeve.

6. The anti-rotation sleeve of claim 1, wherein an inner diameter of said sleeve at said second end receives an outer diameter of said lifter body.

7. The anti-rotation sleeve of claim 1, wherein an outer diameter of said sleeve at said second end receives an inner diameter of said lifter body.

8. The anti-rotation sleeve of claim 1, wherein an axial length of said sleeve is adjustable to an engine-mounting requirement.

9. The anti-rotation sleeve of claim 1, wherein said at least one sleeve feature includes one of a longitudinal groove or a projection; and wherein said at least one lifter body feature includes the other of said longitudinal groove or said projection, thereby limiting radial movement of said lifter body relative to said sleeve.

10. The anti-rotation sleeve of claim 1, wherein a push rod extends between said lifter body and a plunger of said pump to transmit a linear vertical reciprocating motion of said lifter body to said plunger of said pump.

11. The anti-rotation sleeve of claim 1, wherein a plunger of said pump is in contact with said lifter body to transmit a linear vertical reciprocating motion of said lifter body to said pump.

12. The anti-rotation sleeve of claim 1, wherein said sleeve integrates all pump drive components of said pump into a single integral part.

13. A pump drive cartridge assembly of a fuel pump, comprising:

a lifter body including a camshaft follower;

an anti-rotation sleeve connecting said lifter body to a base of said pump, said sleeve slidably receiving said lifter body and said sleeve housing a reciprocation plunger and spring assembly of said pump; and

at least one feature disposed in one of said lifter body or said anti-rotation sleeve that provides orientation and that prevents radial movement of said lifter body relative to said sleeve;

wherein said camshaft follower transmits a rotational motion and lift provided by a camshaft lobe to a linear vertical reciprocating motion of said lifter body, said linear vertical reciprocating motion driving said pump.

14. The pump drive cartridge assembly of claim 13, wherein said plunger is in contact with said lifter body transmitting said linear vertical reciprocating motion.

15. The pump drive cartridge assembly of claim 13, further including a push rod that extends between said lifter body and said plunger of said pump to transmit a linear vertical reciprocating motion of said lifter body to said plunger.

16. The pump drive cartridge assembly of claim 13, wherein said camshaft follower is a roller follower.

17. The pump drive cartridge assembly of claim 13, wherein said lifter body axially slides within said sleeve.

18. The pump drive cartridge assembly of claim 13, wherein said at least one feature disposed in one of said lifter body or said anti-rotation sleeve includes a pair of flat surfaces positioned radially across from each other for providing orientation and preventing radial movement of said lifter body relative to said sleeve.

19. The pump drive cartridge assembly of claim 13, wherein said at least one feature disposed in one of said lifter body or said anti-rotation sleeve includes a projection extending from one of said lifter body or said anti-rotation sleeve and a mating groove formed in the other of said lifter body or said anti-rotation sleeve, wherein said projection axially moves in said groove for providing orientation and preventing radial movement of said lifter body relative to said sleeve.

20. A pump assembly of a direct injection fuel system, comprising:

a pump including a reciprocating plunger and spring assembly extending a base of said pump;

a camshaft lobe; and

a pump drive cartridge assembly arranged between said pump and said camshaft lobe to transmit the rotational motion and lift of said camshaft lobe to a linear vertical reciprocating motion required to drive said pump;

wherein said pump drive cartridge assembly defines features that provide orientation and that prevent radial movement of said pump relative to said camshaft lobe.

21. The pump assembly of claim 20, wherein said pump drive cartridge assembly includes:

a lifter body including a roller follower; and

an anti-rotation sleeve connecting said lifter body to said base of said pump, said sleeve slidably receiving said lifter body opposite from said roller follower and said sleeve housing said reciprocation plunger and spring assembly of said pump;

wherein said features that provide orientation and that prevent radial movement of said pump relative to said camshaft lobe are integrated in said lifter body and said anti-rotation sleeve.

22. The pump assembly of claim 20, wherein said pump drive cartridge assembly includes oil passages that minimize the reciprocating weight of said pump drive cartridge and enable adequate lubrication of interfaces between said pump drive cartridge assembly and said camshaft lobe.