Fuel rail assembly

Abstract: A fuel rail assembly (50) that possesses a number of novel features relating to joints for connecting metal tubes such as crossover (68),inlet (64), and return (74) tubes, to main plastic fuel tubes (52,54); retainer clips for retaining various fuel handling components in sockets formed in the plastic fuel tubes (52,54), such as retaining a fuel pressure regulator (62) in a plastic cup (60) of a main plastic fuel tube (54); and the construction of various plastic sockets in a main plastic fuel tube, such as the cups (56) for receiving the fuel injectors (58).

Description: Field of the Invention This invention relates to a fuel rail assembly for an internal combustion engine. Background and Summary of the Invention It is known to fabricate a fuel rail assembly for a V-type internal combustion engine from two injection-molded main fuel tubes, one for each bank of cylinders, and to convey fuel from one tube to the other through a formed metal crossover tube. Examples of fuel rails are shown in a number of commonly assigned patents. Various forms of retention clips, brackets, etc. are used to connect the various fuel handling components together in fluid-tight fashion. Typically O-ring seals are used to seal the connections. External packaging constraints impose limitations on engine compartments of automotive vehicles, and they can impact on the fuel rail assembly. For example the available vertical space may be limited, necessitating that the fuel rail assembly be as vertically compact as possible. Cost of fabrication is also a consideration, and it is important that a fuel rail assembly be designed for cost-effective fabrication. According to the present invention, there is provided an internal combustion engine fuel rail assembly comprising: a main fuel tube comprising multiple sockets at spaced apart locations along its length; fuel injectors inserted fluid-tight in certain of said sockets; a first component inserted fluid-tight in a first of said multiple sockets; a second component inserted fluid-tight in a second of said multiple sockets proximate said first socket; said first socket and said second socket each comprising a corresponding wall, and retainer means for retaining said first and second components fluid-tight in their respective sockets by preventing their extraction from their respective sockets; the fuel rail characterised in that: one of said walls contains a corresponding through-opening, and said retainer means comprises a bracket having an intermediate portion and end portions at respective ends of said intermediate portion; one of said bracket end portions passes through said through-opening and into an interference relationship with the particular component inserted into the particular one of said first and second sockets whose wall contains said through-opening so as to prevent withdrawal of said particular component from said particular socket, the other of said bracket end portions assumes an interference relationship with said the other of said first and second components to prevent extraction of said second component from its socket; and fastening means for holding said intermediate portion of said bracket fast on said main fuel tube, said fastening means comprises a hole in said intermediate portion of said bracket and a catch projecting from said main fuel tube through said hole to retentively engage said bracket. The disclosure includes drawings that depict a presently preferred embodiment of the invention according to the best mode contemplated at this time for carrying our the invention. Brief Description of the Drawings Fig. 1 is a top plan view of a fuel rail assembly embodying principles of the invention. Fig. 2 is a front elevational view of Fig. 1. Fig. 3 is a rear elevational view of Fig. 1. Fig. 4 is a top plan view, on an enlarged scale, of one bracket used in the fuel rail assembly of Fig. 1. Fig. 5 is a left side elevational view of Fig. 4. Fig. 6 is a view in the direction of arrows 6-6 in Fig. 4. Fig. 7 is a top plan view, on an enlarged scale, of another bracket used in the fuel rail assembly of Fig. 1. Fig. 8 is a right side view of Fig. 7. Fig. 9 is a rear elevational view of Fig. 7. Fig. 10 is an axial end view, on an enlarged scale, of a plug that is used in the fuel assembly of Fig. 1. Fig. 11 is a cross-sectional view taken in the direction of arrows 14-14 in Fig. 10. Fig. 12 is a top plan view of Fig. 10. Fig. 13 is a cross-sectional view taken in the direction of arrows 16-16 in Fig. 12. Fig. 14 is a top plan view, on an enlarged scale and partly in section, of the other main fuel tube of the assembly of Fig. 1. Fig. 15 is a right side view of Fig. 14. Fig. 16 is a bottom view of Fig. 14. Fig. 17 is a transverse cross-sectional view, on an enlarged scale, taken in the direction of arrows 32-32 in Fig. 16. Fig. 18 is a front elevational view, on an enlarged scale, of a crossover tube of the assembly of Fig. 1. Fig. 19 is an axial end view of one end of the tube of Fig. 18. Fig. 20 is an enlarged fragmentary cross-sectional view taken generally in the direction of arrows 35-35 in Fig. 1. Fig. 21 is a somewhat schematic depiction of a relationship of the crossover tube of Figs. 18 and 19 to a socket into which it is inserted. Description of the Preferred Embodiment Figs. 1-3 illustrate a fuel rail assembly 50 that is designed for use with a six-cylinder, V-type internal combustion engine. Fuel rail assembly 50 comprises a first main fuel tube 52 for serving a bank of three cylinders on one side of the engine and a second main fuel tube 54 for serving a bank of a like number of cylinders on the opposite side of the engine. (In Figs. 1-3, these two fuel tubes are tipped slightly about their long dimensions from other drawings Figs. that show each one by itself.) Each main fuel tube 52, 54 is a plastic part that has been injection molded from a suitable material for use in handling pressurised liquid fuels such as gasoline, methanol, etc. Each main fuel tube further comprises a number of sockets for various purposes, including three integral sockets, or cups, 56 into each of which the top of a corresponding top-feed, solenoid-operated fuel injector 58 is inserted and retained in a secure, sealed manner. Main fuel tube 54 further comprises an integral socket, or cup, 60 into which a conventional fuel pressure regulator 62 is inserted and retained in a secure, sealed manner. Fuel delivered from a remote pump (not shown) to fuel rail assembly 50 enters through a fuel inlet tube 64 having one end inserted and retained in a secure, sealed manner in a socket 66 at one end of main fuel tube 52. Tube 52 comprises a main internal fuel passageway (reference 52a in Fig. 17) that serves liquid fuel to all three of its fuel injectors 58. The liquid fuel is delivered to the other main fuel tube 54 through a crossover fuel tube 68 that has one end inserted and retained in a secure, sealed manner in a socket 70 proximate the end of main fuel tube 52 that is opposite the end having socket 66. Tube 68 has another end inserted and retained in a secure, sealed manner in a socket 72 of tube 54. Socket 72 is generally across from socket 70, although it can be readily seen in Fig. 1 that tube 54 is slightly offset in the lengthwise direction relative to tube 52. In this regard, crossover tube 68 contains a suitable bend to provide for this offset. Tube 54 comprises a main fuel passage that serves its three fuel injectors 58 and ends at fuel pressure regulator 62. Excess fuel that is relieved by pressure regulator 62 returns to tank (not shown) via a return tube 74 that is shown only schematically in Fig. 1 but has a connection with a socket 76 at the end of tube 54 proximate cup 60 by means of the same type of connection that connects tube 64 to socket 66. In the operative system, when the pump is delivering fuel to fuel rail assembly 50, pressure regulator 62 regulates the pressure of the fuel delivered to fuel injectors 58 so that a substantially constant pressure differential is maintained between the fuel in the fuel rail assembly and the vacuum in the engine induction system where the nozzle ends of the fuel injectors are disposed. Having described the general organisation and arrangement of fuel rail assembly 50, we may now direct attention to the specific details relating to the various inventive features. A first inventive feature relates to the joints for connecting the ends of crossover tube 68 to the respective main fuel tubes 52, 54. Crossover tube 68 is shown in Figs. 18 and 19 to comprise a length of cylindrical walled tubing that is formed to the desired shape including the formation of circular flanges 78 and 80 proximate each end. A further feature is that each terminal end portion 81, 83 is formed to a non-circular shape that is circular except for a flat 82, 84 respectively, that subtends an acute angle about the axis of the tube. The tube is formed with a symmetrical shape so that either terminal end portion can be inserted into either main fuel tube. Fig. 20 shows detail of socket 70 that is also representative of detail of socket 72, although such detail of the latter socket is not expressly shown by a similar Fig. Socket 70 comprises a stepped bore 86 that is transverse to the length of tube 52, being exactly perpendicular in this instance. At the entrance of stepped bore 86, the wall of socket 70 has a somewhat rectangular shape as viewed in Fig. 15. It also has sufficient thickness in the axial direction of bore 86 to provide for the incorporation of a vertical through-slot 88 that perpendicularly intersects the bore, passing through opposite top and bottom portions of the socket wall. The intermediate adjacent end of tube 52 comprises a circular socket 90. The marginal rim of socket 90 has a sufficient axial dimension to provide for the incorporation of a vertical through-slot 92 that passes through diametrically opposite top and bottom portions of the socket wall. Socket 90 is closed in fluid-tight fashion by means of a closure plug 94, details of which appear in Figs. 10-13. Plug 94 is inserted into socket 90 to an extent sufficient for the plug to present no interference in the direction of through-slot 92. Socket 70 is sufficiently deep to allow an end (83, for instance) of crossover tube 68 to be inserted far enough to assure that the proximate flange 80 is disposed interiorly of the socket relative to through-slot 88. It is this condition that is portrayed in Fig. 20. Plug 94 and crossover tube 68 are retained in this relationship by means of a formed metal bracket 96 that is shown by itself in detail in Figs. 7-9. Bracket 96 is shaped with a generally planar intermediate portion 98 that is between end portions 100, 102. Intermediate portion 98, in plan, has an angled shape corresponding to the angle of the crossover tube to the main fuel tube, 90° in this instance. End portion 100 depends vertically from one end of intermediate portion 98 while end portion 102 depends vertically from the opposite end of intermediate portion 98. End portion 100 has the shape of an elongated rectangular tongue while end portion 102 comprises a slot 104 that endows its distal end with a fork shape. Intermediate portion 98 is also provided with a small rectangular-shaped through-hole 106. Fig. 20 shows bracket 96 having been assembled to fuel rail assembly 50 to retain crossover tube 68 and plug 94 in place. Assembly of the bracket is accomplished by disposing it over tube 52 with the respective end portions 100, 102 aligned with the respective through-slots 92, 88, and then bodily displacing the bracket downwardly so that the two end portions enter their respective through-slots. Tube 52 is provided with an integral upstanding catch 108 that has an inclined surface 110 designed to be engaged by an edge of hole 106 as bracket 96 approaches the fully installed position shown by Fig. 20. Upon such engagement, the continued downward forceful displacement of bracket 96 causes catch 108 to be flexed out of the way allowing the bracket to continue its downward displacement toward its final position. The fit of the bracket's end portions 100, 102 in the respective through-slots 92, 98 constrains the bracket against any substantial displacement except in the vertical direction. Accordingly, when the bracket has been displaced downwardly sufficiently to cause the edge of hole 106 to move off surface 110, catch 108 snaps back to the position illustrated in Fig. 20 to present an interference with the marginal edge of hole 106 that prevents the bracket from being moved vertically upwardly. This completes the installation process. It can be further seen in Fig. 20 that flange 80 has been captured by the forked distal end of end portion 102 while end portion 100 presents an obstruction that prevents removal of plug 94. An O-ring seal 112 that was disposed over the end of the crossover tube before its insertion into socket 70 is captured between flange 80 and an internal shoulder of bore 86. The shape of both crossover tube 68 and bore 86 is circular in this region where O-ring seal 112 is disposed. More interiorly, the non-circular terminal end portion of the crossover tube is received in a non-circular portion of bore 86 which has a shape generally corresponding to that of the terminal end portion of the crossover tube containing flat 84 but allowing a limited amount of relative circumferential positioning of the crossover tube within the socket, for example about 20°. Moreover, the relative axial dimensions are such that the captured crossover tube can move a limited axial amount relative to socket 70 while retaining the constraint on the amount of limited circumferential positioning between the two. This type of joint between crossover and main tubes is especially advantageous for the purpose of facilitating installation of fuel rail assembly 50 on an engine. Fig. 21 schematically presents the construction that allows the limited circumferential positioning of the tube within the socket, the non-circular portion of the socket being designated 86a. It is to be observed that the axial dimension of socket 90 is relatively small because of externally imposed packaging constraints. This can give rise to difficulty in the inserting of closure plug 94. The particular design of plug 94 is intended to avoid this difficulty. Plug 94 comprises a shoulder 114 onto which is disposed an O-ring seal 115. When the plug is inserted into socket 90, it is confined by shoulder 114 to provide a fluid-tight seal with the wall of the fuel tube. Toward its exterior face, plug 94 is provided with two axially extending, radially projecting ribs 116, 117 on opposite diametrical sides. As can be seen in Fig. 20, the marginal rim of socket 90 is provided with respective slots 118, 120 for receiving the respective ribs 116, 117 when the plug is closing the socket. The leading edge has a chamfer 122 to facilitate the insertion process and when the plug has been inserted to the appropriate depth, a large vertical slot 124 that is present in the exterior face of the plug provides a clearance that allows end portion 100 of the bracket 96 to pass completely through as seen in Fig. 20. A similar type of joint connects the other end of crossover tube 68 to fuel tube 54. While the general principles of the joint are the same, the bracket that is used for this particular joint has a slightly different shape, and it is portrayed by itself in Figs. 4-6 where its various features are identified by primed versions of the corresponding reference numerals used for bracket 96. Other corresponding parts of fuel tube 54 and its end closure plug are also identified by primed versions of the corresponding reference numerals used for the same parts of fuel tube 52 and for closure plug 94. While a presently preferred embodiment of the invention has been illustrated and described, it should be appreciated that principles are applicable to other embodiments.

Claims: An internal combustion engine fuel rail assembly (50) comprising: a main fuel tube (52) comprising multiple sockets (56, 70, 90) at spaced apart locations along its length; fuel injectors (58) inserted fluid-tight in certain of said sockets (56); a first component (94) inserted fluid-tight in a first (90) of said multiple sockets; a second component (68) inserted fluid-tight in a second (70) of said multiple sockets proximate said first socket; said first socket and said second socket each comprising a corresponding wall, and retainer means (96) for retaining said first and second components (94, 68) fluid-tight in their respective sockets (90, 70) by preventing their extraction from their respective sockets; the fuel rail characterised in that: one of said walls contains a corresponding through-opening (92), and said retainer means comprises a bracket (96) having an intermediate portion (98) and end portions (100, 102) at respective ends of said intermediate portion; one of said bracket end portions (100) passes through said through-opening (92) and into an interference relationship with the particular component (94) inserted into the particular one of said first and second sockets whose wall contains said through-opening (92) so as to prevent withdrawal of said particular component from said particular socket, the other of said bracket end portions (102) assumes an interference relationship with the other (68) of said first and second components to prevent extraction of said second component (68) from its socket (70); and fastening means (106, 108, 110) for holding said intermediate portion (98) of said bracket fast on said main fuel tube (52), said fastening means comprises a hole (106) in said intermediate portion of said bracket and a catch (108) projecting from said main fuel tube through said hole to retentively engage said bracket. An internal combustion engine fuel rail assembly as set forth in Claim 1, characterised further in that said intermediate portion (98) of said bracket is substantially planar, and said bracket end portions (100, 102) depend from said substantially planar intermediate portion of said bracket. An internal combustion engine fuel rail assembly as set forth in Claim 1 characterised further in that said first component that is inserted fluid-tight into said first of said multiple sockets is a plug (94) that closes an otherwise open end of said main fuel tube, and said second component (68) that is inserted fluid-tight into said second of said multiple sockets is an end (83) of a further tube that is in fluid communication with said main fuel tube. An internal combustion engine fuel rail assembly as set forth in Claim 3 characterised further in that the bracket end portion (100) that prevents extraction of said plug (94) from said first socket is a flat blade, and the bracket end portion (102) that prevents extraction of said further tube from said second socket is a flat forked blade (104). An internal combustion engine fuel rail assembly as set forth in Claim 1 characterised further in that the other of said walls contains a respective through-opening (88), and said other (102) of said bracket end portions passes through said through-opening of said other of said walls to assume the interference relationship with said other (68) of said first and second components.

Inventors: HORNBY MICHAEL J, VATTELANA GARY D, HORNBY, MICHAEL J., VATTELANA, GARY D.
Applicants: SIEMENS AUTOMOTIVE CORP LP, SIEMENS AUTOMOTIVE CORPORATION
Application year: 1995
Main classification: F02M69
IPC codes: F02M69, F02M55, F02M51