This application is a national stage application under 35 USC 371 of PCT Application No. PCT/EP2015/056388 having an international filing date of Mar. 25, 2015, which is designated in the United States and which claimed the benefit of GB Patent Application No. 1408060.0 filed on May 7, 2014 the entire disclosures of each are hereby incorporated by reference in their entirety.
The present invention relates to an electrical connector assembly for a fuel injector and also to the fuel injector equipped with such connector.
A fuel injector is provided with an actuator arranged in its body and which electrical wires upwardly extend in an axial bore of the injector body. The bore is a blind hole and the wires protrude through a seal arranged in the wall of the body to be electrically connected into an electrical connector. Said connector has a plastic body and metallic electrical terminals which are at one end connected to the wires of the actuator and, at the other end, adapted to receive a complementary connector. The fuel injector is also provided with a back leak flow channel wherein fuel, at low pressure, flows from a control valve toward a low pressure reservoir. The injector is provided with an outlet pipe radially protruding from the injector body. In certain injectors the axial bore of the injector, wherein are the wires, is part to said back leak channel and, in use, fuel wets said wires.
The manufacturing and assembly of the injector raises numerous difficulties such as manufacturing of the blind bore, of the outlet pipe, the fixation of the connector onto the injector body or the electrical connection of the wires on the terminals.
Accordingly, it is an object of the present invention to provide a connector assembly and a complete injector solving at least partially the above problems.
In carrying out the above object and other objects, features, and advantages, the present invention provides an electrical connector assembly of a fuel injector extending along a first axis. The connector has a body with external walls defining an internal volume and an internal wall dividing the connector in a first part adapted to be fixed in a complementary engagement with the body of the injector and, in a second part adapted to receive another electrical connector. The electrical connector assembly further comprises at least one electrical terminal extending through the internal wall, along a second axis, from an inner extremity protruding in the inner volume of the first part of the body to an outer extremity protruding in the outer volume of the second part of the body. The outer extremity is shaped to receive in a complementary engagement an electrical terminal of said another electrical connector.
The connector assembly is adapted to be in fluid communication with the back leak return conduit of the injector so that, in use, fuel may enter the inner volume of the first part of the body and wet the electrical terminal.
The inner volume of the first part of the body is substantially cylindrical extending along the first axis from a lower extremity and it is adapted to engage the body of the injector to an opposite upper extremity. The cylindrical volume opens at both extremities, the connector assembly further comprising a sealing cover adapted to seal the upper extremity.
The connector assembly may further be provided with an outlet pipe integral to the connector body and adapted to be in fluid connection with the internal back leak channel of the injector. Alternatively, the outlet pipe may be integral to the sealing cover.
The central portion of the terminal that extends through the internal wall is cylindrical or conical.
The connector assembly further comprises sealing means arranged between the central portion of the terminal and the internal wall so that the inner and outer volumes, of the first and of the second parts are sealed from each other.
The inner extremity of the terminal is integral to the central portion and is made in a first conductive material and, the outer extremity is non-integral and is fixed to the central portion, the outer extremity being made in a second conductive material.
In another alternative, the inner and the outer extremities of the terminal are both integral to the central portion and are all made in a first conductive material.
The first material is free of Cu and of Zn or, alternatively, the first material is externally coated with a coating free of Cu and of Zn.
The connector assembly may further comprise locking means adapted to maintain in position the terminal relative to the connector body.
The locking means comprise first locking means for locking the terminal in rotation about the second axis and also, second locking means for locking the terminal in translation along said second axis.
The locking means may be a complementary engagement of a portion of the terminal, such as a groove, and of part of the sealing cover, such as a fork-like feature or a notch.
The locking means may comprise a sub-assembly of the terminal complementary engaged in a holding part, said sub-assembly being over-molded in the connector body.
The connector may further comprise connector locking means adapted to fix the connector assembly on the injector body.
In an embodiment, the connector body is plastic molded and the locking means comprise at least one metal insert fixed the body and axially protruding from said plastic body at the periphery of the lower extremity.
The at least one metal inserts may be over molded in the connector body, or may be glued on the outer periphery of the connector body or may be crimped on the periphery of the connector body by a circling collar.
The invention further extends to a fuel injector having a body extending along a first axis, an actuator arranged in said body and a connector assembly arranged on said body, the injector body having an internal bore in which at least one electrical lead extends from the actuator to the connector assembly wherein it is electrically connected to an electrical terminal, the internal bore being part of a back leak return channel in witch, in use, low pressure fuel may flow toward an outlet. The connector assembly is as set in the preceding lines and, the inner volume of the first part of the connector assembly is in fluid communication with the internal bore of the injector body so that, in use, fuel may enter the inner volume of the connector and wet the electrical terminal.
More specifically, in an embodiment, the outlet is arranged integral to the connector assembly. In another embodiment, the outlet is arranged integral to a sealing cover adapted to seal the connector body.
The electrical wires may be laser welded on the inner extremity of the terminal.
The injector body has a male cylindrical portion that engages in a complementary female lower extremity of the connector body and, the injector body is provided with an annular groove in which are bent the protruding part of the metal insert so that, the connector assembly is fixed in position on the injector body.
The injector body has a male cylindrical portion that engages in a complementary female lower extremity of the connector body and, the injector body is provided with an annular disc face transversal to the first axis, the protruding part of the metal insert being welded on said disc-face so that, the connector assembly is fixed in position on the injector body.
The injector body has a male cylindrical portion that engages in a complementary female lower extremity of the connector body, both the connector body and the injector body being provided with complementary aligned radial holes, and in which is inserted a pin so that, the connector assembly is fixed in position on the injector body.
The invention further extends to a method for assembling a fuel injector as set in the preceding lines. The method comprises the following steps:
The present invention is now described by way of example with reference to the accompanying drawings in which:
To ease and clarify the following description the top-down orientation of the figures is arbitrarily chosen and, words and expressions such as “above, under, over, below . . . ” may be utilized without any intention to limit the invention.
In reference to
As well known, the fuel injector 10 is also provided with a control valve, a nozzle and high pressure fuel channels in which in use, fuel flows from an inlet to the nozzle. This will not be discussed further as not being part of the core of the invention.
Above the actuator 14, the body 12 is provided with a bore 22 that upwardly axially extends and opens in the top end face 24 of the body 12. The axial bore 22 is part of a back leak channel enabling low pressure fuel to flow out of the injector 10, via an outlet pipe 26, and then return to a low pressure reservoir. A L-shape outlet pipe 26 is represented in
On the upper end 20 of the injector 10 is arranged the connector assembly 18 more detailed in the following figures. The connector 18 comprises a plastic body 28 having external envelop 30 and an internal wall 32 that separates the connector 18 in a first part 34, complementary arranged on the upper end 20 of the injector body 12 and, in a second part 36 adapted to receive another connector, so that the actuator 14 can be electrically connected to the control unit.
The first part 34 is substantially cylindrical extending on the top of the injector body 12 along the longitudinal axis A1 and defining a cylindrical inner volume 38.
The second part 36 extending along a second axis A2 perpendicular to the longitudinal axis A1 and defines an outer volume 40 shaped to receive the complementary connector, not represented. Alternative constructions where the two axes A1, A2, are not perpendicular are also possible.
The interface between the first part 34 of the connector body 28 and the injector body 12 is a male-female cylindrical engagement along the longitudinal axis A1 where the lower extremity 42 of said first part 32 engages over the upper end 20 of the injector body 12. More in details, the injector body 12 has, from its top end face 24, a male cylindrical face 44 downwardly extending until joining a transversal a radial disc-face 46 and, the first part 34 of the connector body 28 is provided with a complementary lower recess 48 having a female cylindrical wall 50 and a transversal ceiling wall 52 centrally holed.
The ceiling wall 52 divides the inner volume 38 into said lower recess 48, below the ceiling 52, and an upper recess 54, above the ceiling wall 52. The connector body 28 is further provided with at least one over-molded metal insert 56 downwardly protruding out of the plastic envelop 30 and being, as shown on
Alternatively, the metal insert 56 could be bent inwardly or could be not bent at all, provided they enable fixation of the connector. Alternative means of fixation will be further described.
The assembly of the connector onto the injector body 12 is sealed by an O-ring 58 arranged between the cylindrical face 44 and the female cylindrical wall 50 or between the top end face 24 and the ceiling wall 52. A specific groove may be provided to accommodate the O-ring or by any other sealing means such as sealing paste, gasket . . . .
Opposite to the lower extremity 42 is the open upper extremity 60 of the first part of the connector body 28. Said upper extremity 60 defines the upper recess 54 mentioned above.
On the top of the upper extremity 60 is arranged a sealing cover 62 that closes the upper opening of the connector body 28. The cover 62 comprises a circular main face 64 transversal to the longitudinal axis A1, from which extends a cylindrical centering wall 66 that complementary engages in the connector body 28. When in place the sealing cover 60 may be laser welded to ensure sealing of the interface.
The connector assembly 18 also comprises a plurality of electrical terminals 68. Only one is represented on
More in detail and, in reference to
In place in the connector body 28, the vertical connection portion 78 of the terminal lies against the outer face of the internal wall 32 where it engages a small recess 82 complementary shaped to the connection portion 78, said engagements creates rotation locking means 84 preventing the terminal to rotate about the second axis A2.
As visible on the figures, said cylindrical portion 80 comprises a first groove, that is a sealing groove 86, wherein is arranged another O-ring 88 sealing across the bore 70 of the internal wall 32. Other sealing means such as paste, gasket or tight press fit are also possible alternatives.
The cylindrical portion 80 is further provided with a second groove, that is a locking groove 90, in which engages a notch 92 provided in the centering wall 66 of the cover 62. In
In use as represented on the figure, the inner extremity 74 of the terminal is substantially in the center of the upper recess 54 where end the electrical leads 16 of the actuator 14 and, connection such as laser welding is made.
On the embodiment represented on
Other alternatives of shapes of terminals can easily be chosen without departing from the present invention.
In use, the back leak fuel flows in the bore 22 and is able to enter the inner volume 38 of the connector body 28. Consequently, as represented on
One of the major interests of the present invention is to enable to manufacture a through bore 22 in the injector body 12 opening in the top face 24. As fuel is now allowed to enter the connector body 28, another potential advantage is to arrange a plastic molded outlet pipe 26 integral to the connector body 12 or to the sealing cover 62, and remove from the injector body 12 the original outlet pipe as shown on
First fixation means has been described in relation to
In reference to
On
Another fixation alternative is represented on
The invention here above described further extends to the process of manufacturing and assembly of the injector 10.
Alternatives have been presented for positioning the outlet pipe 26, or for fixing the connector onto the injector body and anyone of these alternatives can be used in the process below. Also, the order of certain steps can be reversed without any issue.
In reference to the embodiment of
Alternative constructions are possible where instead of notches provided in the cover 62, the translation of the terminals along the second axis A2 can be prevented via a complementary shape of the internal wall 32.
In a yet further alternative, the terminal 68 could be over-molded in the internal wall 32 either alone, or as part of a sub-assembly 108 as sketched on
The following references have been used in this description:
Number | Date | Country | Kind |
---|---|---|---|
1408060.0 | May 2014 | GB | national |
Filing Document | Filing Date | Country | Kind |
---|---|---|---|
PCT/EP2015/056388 | 3/25/2015 | WO | 00 |
Publishing Document | Publishing Date | Country | Kind |
---|---|---|---|
WO2015/169500 | 11/12/2015 | WO | A |
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Number | Date | Country | |
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20170067428 A1 | Mar 2017 | US |