The present invention relates to engine management systems and components of internal combustion engines; more particularly, to fuel injection systems; and most particularly, to apparatus and method for connecting a fuel injector to a fuel rail.
Fuel rails that are used to deliver fuel to individual fuel injectors of internal combustion engines are well known. A fuel rail assembly, also referred to herein simply as a fuel rail, is essentially an elongated tubular fuel manifold connected at an inlet end to a fuel supply system and having a plurality of ports for mating in any of various arrangements with a plurality of fuel injectors to be supplied. In what is referred to as a return-less system, a fuel return line does not fluidly connect the fuel rail back to the fuel supply system at a rail outlet end. In a “return” system, a fuel line fluidly connects the end of the fuel rail opposite the inlet end back to the fuel supply system. Typically, a fuel rail assembly includes a plurality of fuel injector sockets in communication with a manifold supply tube, the injectors being inserted into the sockets. Fuel rails are typically used on internal combustion engines with multi-point fuel injection systems.
Typically, a fuel injector is connected to a fuel rail using two different methods. In a first prior art method, a clip, such as a c-clip, is used to hold the injector to the fuel injector socket of the fuel rail. The clip also prevents the injector from rotating within the socket. In a second prior art method, a lower and an upper cushion hold the injector between the fuel injector socket and the intake manifold or the cylinder head. In this case the fuel injector socket typically includes a finger that prevents rotation of the injector within the socket. Both prior art methods utilize separate parts, such as the clip or the cushions, which creates extra costs and requires cycle time for installation. Therefore, it is desirable to reduce the number of parts required in the assembly of a fuel injection system.
Efforts to eliminate separate parts for the injector to fuel rail installation have been undertaken in more recent prior art with limited success. Features integrated within the fuel injector socket, the injector, or both, often required relatively tight tolerances, which may result in increased machining time and higher production costs.
U.S. Pat. No. 5,301,647, for example, teaches a fastening clip for integral formation with a portion of the body of a fuel injector and that provides attachment and retention. Modifications to the injector are needed to integrate a cylindrical wall including a plurality of apertures and catches.
U.S. Patent Application No. 2006/0065244, for example, discloses an integral device that provides rotational orientation while allowing axial sliding engagement of the fuel injector relative to the socket after assembly. Retention tabs integrated within the socket engage with corresponding grooves integrated within the injector.
What is needed in the art is a fuel injector to fuel rail connection that does not require separate parts or expensive machining operations.
What is further needed in the art is a relatively simple connection of a fuel injector to a fuel injector socket of a fuel rail that enables efficient assembly as well as disassembly if needed.
It is a principal object of the present invention to provide a method for connecting a fuel injector to a fuel rail that reduces manufacturing cycle time and provides easier package for shipping compared to current methods.
Briefly described, a fuel injector to fuel rail connection, in accordance with the invention, includes corresponding attachment features integrated into a fuel injector socket of a fuel rail and a fuel injector. The corresponding attachment features not only connect the fuel injector securely to the fuel injector socket of a fuel rail, but also provide a force to prevent injector rotation relative to the socket that is higher than the force provided by known prior art attachment features. By introducing corresponding attachment features in accordance with the invention, separate prior art parts such as clips or cushions can be eliminated simplifying the fuel injector installation process and reducing assembly costs. Furthermore, the corresponding attachment features not only enable simple connection and disconnection of a fuel injector to a fuel injector socket of a fuel rail, but can also be integrated into existing injector to fuel rail assembly processes and are applicable in any fuel injection system. Still further, the corresponding attachment features in accordance with the invention may be used with metal fabricated fuel rail assemblies as well as for fuel rail assemblies where the manifold supply tube and the fuel injector sockets are overmolded with a plastic material.
In accordance with the present invention, the fuel injector socket includes a slot that receives a projection included in the fuel injector. An anti-rotation feature integrated into the slot prevents radial movement of the fuel injector relative to the socket. Fuel pressure prevents axial movement of the fuel injector relative to the socket during operation.
In further accordance with the present invention, the fuel injector socket includes a tab having an anti-rotation feature and securing the socket to a projection integrated in the fuel injector. The injector to socket assembly may be designed either such that the tab is flexible or that the projection includes a locking feature.
In still further accordance with the present invention, the fuel injector includes a groove that includes the anti-rotation feature and receives the socket that includes a tab having an inward pointing lip. During installation, the fuel injector is simply pushed axially into the socket to engage the tab of the socket with the groove of the injector. For disassembly, the fuel injector can be pushed up, rotated, and finally pulled out from the socket.
The present invention will now be described, by way of example, with reference to the accompanying drawings, in which:
Corresponding reference characters indicate corresponding parts throughout the several views. The exemplification set out herein illustrates one preferred embodiment of the invention, in one form, and such exemplification is not to be construed as limiting the scope of the invention in any manner.
Referring to
Fuel injector socket 20 has a generally cylindrical elongated shape and extends longitudinally along central axis 12 from a first end 22 to a second end 24. The first end 22 is in fluid communication with the fuel supply tube. The second end 24 is open and receives fuel injector 30. Socket 20 includes a primary slot 26 positioned proximate to second end 24. Slot 26 includes a first segment 262, a second segment 264, and a third segment 266, all in fluid communication with each other. First segment 262 extends upwards in axial direction from second end 24 of socket 20 and, therefore is open at end 272. First segment 262 serves as an inlet. Second segment 264 extends radially from end 274 of first segment 262 and connects first segment 262 with third segment 266. Third segment 266 extends downwards from end 276 of second segment 264 in axial direction towards second end 24. Third segment 266 of slot 26 does not extend all the way to second end 24 and, consequently, is closed at bottom 268. Third segment 266 forms an orientation stopper 28 that prevents rotational movement. Fuel injector socket 20 may be manufactured by machining, forming or molding.
Fuel injector 30 includes a primary projection 34 that corresponds with primary slot 26. Projection 34 may have, but is not limited to, a rectangular shape and extends outwards from the outer surface 32 of injector 30. Projection 34 is positioned axially below and at a distance from an o-ring 36 of injector 30 such that projection 34 does not interfere with the sealing process during installation of injector 30 in socket 20. The dimensions of projection 34 are chosen such that projection 34 is able to travel easily within slot 26 of socket 20. The depth of projection 34 is chosen such that projection 34 preferably extends outward beyond the outer surface 202 of socket 20. The width of projection 34 is chosen such that projection 34 fits into third section 266 of slot 26. The height of projection 34 is chosen such that projection 34 can be moved up and down in axial direction within second segment 264 of slot 26.
During installation of injector 30 in socket 20, injector 30 is moved in an axial direction towards the second end 24 of socket 20. The projection 34 of injector 30 is in line with the first section 262 of slot 26 of socket 20. During upward movement of injector 30, the projection 34 enters and travels within first segment 262 of slot 26. By turning injector 30 clockwise (looking upward along central axis 12 in
Optionally, as a second method of installation of injector 30 in socket 20, projection 34 may be aligned with third section 266. Then, during upward movement of injector 30, the projection 34 contacts second end 24 and flexes closed bottom 268 away from central axis 12 allowing projection 34 to snap into segment 266. In this position, projection 34 rests at the bottom 268 of third segment 266 of slot 26.
During operation, fuel pressure of fuel supplied by the fuel supply tube (not shown) will press injector 30 down in an axial direction away from socket 20. As a result, projection 34 is held down at the bottom 268 of third segment 266 of slot 26 in a locked position. In this locked position, radial movement of injector 30 relative to socket 20 is prevented clockwise and counter-clockwise by orientation stopper 28 and the wall 270 of third segment 266 of slot 26 opposite from orientation stopper 28, respectively.
During dis-assembly of injector 30 from socket 20, injector 30 is pushed up in an axial direction towards first end 22 of socket 20, is turned counter-clockwise in radial direction (looking upward along central axis 12 in
While socket 20 is shown in
Referring to
Slot 16 only includes a first section 162 and a second section 164 that are comparable to first section 262 and second section 264 of slot 26, respectively. By omitting a third segment comparable to segment 266 of slot 26, no orientation stopper 28 is formed. Thus, slot 16 simplifies correct installation of injector 30 in socket 20 and provides additional support for injector 30 in axial direction when installed, but does not provide an anti-rotation structure, such as orientation stopper 28. Slot 16 has generally the same dimensions as slot 26 to ensure effortless installation of injector 30 in socket 20. More than one slot 16 may be included in socket 20 and more than one corresponding projection 18 may be included in injector 30.
Referring to
During installation of injector 30 in socket 40, injector 30 is moved in axial direction towards the second end 24 of socket 40. The projection 34 of injector 30 is not in line with tab 42. Once injector 30 is pushed into socket 40, injector 30 is turned counter-clockwise (looking upward along central axis 12 in
Optionally, as a second method of installation of injector 30 in socket 40, projection 34 may be aligned with groove 44. Then, during upward movement of injector 30, the projection 34 contacts the bottom of tab 42 and flexes tab 42 away from central axis 12 allowing projection 34 to snap into opening 46 above groove 44. In this position, projection 34 rests in groove 44.
During operation, fuel pressure of fuel supplied by the fuel supply tube (not shown) will press injector 30 down in axial direction away from socket 40. As a result, projection 34 is held in groove 44 in a locking position.
During dis-assembly of injector 30 from socket 40, injector 30 is pushed up in axial direction towards first end 22 of socket 40, moving projection 34 out of the locked position, is turned clockwise in radial direction (looking upward along central axis 12 in
Referring to
Referring to
During installation, the fuel injector 30 is moved in an axial direction towards the second end 24 of socket 60. The projections 34 of injector 30 are preferably in line with corresponding tabs 62. During the axial upward movement, projections 34 will slide underneath ramps 622 of corresponding tabs 62 flexing tabs 62 at end 624 outward and away from axis 12 until the voids 64 are reached. When projections 34 enter corresponding voids 64, tabs 62 will flex back towards axis 12 into resting position thereby locking projections 34 in place. Tabs 62 including voids 64 limit axial movement and prevent radial movement of injector 30 relative to socket 60 when installed during operation. For dis-assembly, tabs 62 are flexed outwards away from axis 12 and injector 30 is pulled downward in axial direction out of socket 60.
Referring to
During installation of injector 30 in socket 60 (shown in
Referring to
Tab 72 does not extend beyond second end 24 of socket 70. Tab 72 is designed to be flexible allowing tab 72 to be flexed outward away from axis 12. Tab 72 includes an inward oriented lip 74 positioned proximate to the second end 24. In a preferred embodiment, socket 70 includes at least two tabs 72 that are positioned radially equal-spaced from each other.
Injector 80 includes a notch 82. Notch 82 may be integrated in the body of injector 80 and may be located within a section 84 below o-ring 36. Notch 82 is designed to receive lip 74 of socket 70. Section 84 of injector 80 includes a flat sidewall 86 that is, in the example shown having two tabs, at a 90-degree angle to notch 82. In a preferred embodiment, injector 80 includes at least two notches 82 that are positioned opposite from each other and at least two flat sidewalls 86. One sidewall 86 is always positioned between two notches 82. Injector 80 further includes an annular groove 88 positioned just below notches 82.
During installation of injector 80 in socket 70, notches 82 are lined up with corresponding tabs 72. Injector 80 is pushed upward in axial direction towards socket 70. During the upward movement, tabs 74 are flexed outward. When lips 74 meet corresponding notches 82, lips 74 engage with notches 82.
To dis-assemble injector 80 from the socket, injector 80 is pushed upward such that lips 74 of tabs 72 disengage from notches 82 and slide into annular groove 88. Injector 80 is then rotated, either clock-wise or counter-clockwise, until lips 74 are lined up with flat sidewalls 86. Now, injector 80 is pulled out from socket 70 by moving injector 80 downward in axial direction away from socket 70. During this movement, lips 74 slide over flat sidewalls 86 releasing injector 80.
As compared to the prior art, fuel injection system 10, in accordance with the invention, beneficially provides corresponding attachment features integrated in fuel injector sockets 20, 40, 60 and 70 and integrated in fuel injectors 30 and 80 that not only connect the fuel injector 30 securely to the fuel injector sockets 20, 40, and 60 and the injector 80 to socket 70, but also provide a higher force to prevent injector rotation relative to the socket. Stronger anti-rotation structures, for example orientation stopper 28 and 48, tab 62 and void 64, or tab 72 and notch 82, are provided, while the connection of injector to socket is simplified. 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.
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