FR2741396A1 - DEVICE FOR FASTENING A FUEL INJECTOR TO A CELL OF AN INTERNAL COMBUSTION ENGINE - Google Patents

Abstract

The present invention relates to a device for fixing a fuel injector to a cylinder head of an internal combustion engine. The device is characterized in that a recess (6), preferably formed by a peripheral groove, opens onto the periphery of a cylindrical portion (4) of the injector (1) and receives an intermediate part (7), preferably an elastic metal ring, projecting partially from the recess (6) and the flange (3) is supported by a circular support base (3a) on an emerging part of the intermediate part (7). The invention finds application in the automotive field.

Description

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  The present invention relates to a device for fixing a fuel injector on a cylinder head.

internal combustion engine.

  Such fastening devices are known in which a lower end portion of the injector is held in abutment, by means of a non-elastic sealing washer, generally made of copper, on an internal face of the breech perpendicular to the longitudinal axis of the injector by a flange having two opposing bosses respectively bearing on two flats

machined body of the injector.

  However, these known devices are not at all suitable for compact injectors of small diameter, for example 17 mm, on which it is almost impossible.

  to machine the two flats of support of the flange.

  Another fastening device is known according to which the injector is clamped in the cylinder head by a central nut resting on a ring integral with the body of the injector. This known device has the disadvantage that there is a risk of loosening of the central nut due to different thermal expansions of the injector and the cylinder head and the central nut does not allow elastic recovery efforts between the injector and the cylinder head during such dilations. Thus, it is necessary to tighten the central nut to a very high torque, but such clamping may crush the sealing washer between the injector and the cylinder head so that the latter may not be over.

  ensure its sealing function.

  The present invention aims to eliminate the above disadvantages of known devices by providing a device for fixing a fuel injector on a cylinder head of an internal combustion engine, of the type in which the injector is kept partially engaged. in a cylindrical housing opening from the cylinder head on a face thereof perpendicular to the injector by means of a flange spaced from this face and fixed to the cylinder head by two screws perpendicularly crossing this face, two bosses

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  opposing the flange, turned towards this face, being applied to two bearing zones at least diametrically opposite of the injector and which is characterized in that the bearing zones are formed in a recess opening on the periphery of a cylindrical portion of the injector and receiving an intermediate piece emerging partially from the recess and in that each boss of the flange, external to the cylindrical portion of the injector, is

  applied on an emergent part of the intermediate part.

  According to one embodiment of the invention, the recess is a peripheral groove and the two bearing zones are interconnected to form a bearing zone.

  circular for the intermediate piece.

  Preferably, the intermediate piece is constituted

an elastic metal ring.

  According to an alternative embodiment, the two bosses of the flange are interconnected by forming a circular support base of the flange on the two support zones of the injector. Advantageously, a ring is interposed between the ring

and the bridle.

  The base of the flange includes a chamfer

cooperating with the rush.

  According to an alternative embodiment, the ring comprises a

chamfer cooperating with the rush.

  According to another embodiment, each bearing zone is formed in a radial recess consisting of a blind hole receiving a bearing pin of a corresponding boss.

of the bridle.

  The invention will be better understood, and other purposes, features, details and advantages thereof

  will become clearer during the description

  explanatory text which will follow with reference to the accompanying schematic drawings given solely by way of example illustrating several embodiments of the invention and in which:

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  - Figure 1 is a longitudinal sectional view of the device of the invention for fixing a fuel injector on a cylinder head of an internal combustion engine; - Figure 2 is a partial sectional view along the line II-II of Figure 1; - Figure 3 is a partial perspective view along the arrow III of Figure 2; FIG. 4 is a perspective view of an injector provided with a fixing device according to a second embodiment of the invention; and - Figure 5 is a perspective view of an injector provided with a fixing device according to a third embodiment. Referring to FIGS. 1 to 3, reference numeral 1 denotes a fuel injector fixed on a cylinder head 2 of a

internal combustion engine.

  More specifically, the injector 1 has its lower end portion held in abutment, by a flange 3, on an inner face 2a of the yoke 2 perpendicular to the longitudinal axis of the injector 1 and constituting the bottom of a cylindrical housing 2b of the yoke 2 for receiving a cylindrical portion 4 of the body of the injector 1. A non-elastic copper sealing ring R is interposed between the end portion 1a and the inner face 2a of the yoke 2 The flange 3 is fixed to the cylinder head by two fixing screws 5 crossing perpendicularly the face 2c of the cylinder head 2, perpendicular to the longitudinal axis of the injector 1, and on which the housing opens

  cylindrical 2b. The flange 3 is spaced from the face 2c

above it.

  According to the invention, the cylindrical portion of the cylindrical portion 4 of the body of the injector 1 located above the face 2c of the yoke 2 and outside thereof, comprises a recess 6 opening on the periphery of this cylindrical portion and constituted by a peripheral groove forming a circular bearing zone for an intermediate piece 7

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  consisting of a split ring or elastic metal ring mounted in the peripheral groove 6 partially projecting

of it.

  The flange 3 comprises at its lower part a circular base 3a turned towards the face 2c and bearing on the projecting portion of the ring 7. This base 3a support may comprise a chamfer 3b coming into contact with the part

corresponding projection of the ring 7.

  The flange 3 may be made of cast iron with inside the through hole 3c of the cylindrical portion 4, the injector 1 and the two symmetrical wings 3d are traversed respectively by the two fixing screws 5 of

the flange 3.

  The assembly of the injector 1 in the breech 2 spring

  already partly from the foregoing description and is going to be

now briefly explained.

  The flange 3 is first mounted on the injector and positioned above the groove 6 of the cylindrical portion 4. Then, the rod 7 is slid over the cylindrical portion 4 of the body of the injector 1 until it engage in the receiving groove 6. Finally, the flange 3 is lowered with the injector until it bears on the protruding portion of the rod 7 and is fixed to the yoke 2 by the fixing screws 5 so as to maintain the injector 1 in partial commitment in the

  cylindrical housing 2b of the cylinder head 2.

  According to the embodiment shown in FIG. 4, the support base 3a of the flange 3 is formed by two bosses which, instead of being bearing respectively directly on the two corresponding projecting parts of the rod 7, are in contact with each other. on two diametrically opposed zones of a ring 8 interposed between the rod 7 and the flange 3. Of course, the two bosses 3a could alternatively be directly bearing on the rod 7. In addition, the ring 8 may comprise a circular chamfer internal (not shown) contacting the

  corresponding circular part of the ring 7.

  According to the embodiment shown in FIG. 5, the two opposite bosses 3a of the flange 3 are applied

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  respectively on two diametrically opposed bearing zones of the injector 1 each made in a radial recess consisting of a blind hole (not shown) receiving a pin

  9 serving as support for the corresponding boss 3a.

  The fastening device according to the invention reconciles a small footprint and a good elastic recovery of the forces resulting from different thermal expansions of the injector and the cylinder head, in particular thanks to the use of the two relatively long screws for fastening the flange, thus ensuring a good hold with moderate tightening of the injector and an excellent sealing since the sealing washer R is not likely to be crushed during the

  tightening of the injector by the flange 3.

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Claims (9)

  1. Device for fixing a fuel injector (1) on a cylinder head (2) of an internal combustion engine and of the type in which the injector (1) is held partially engaged in a cylindrical housing (2b) emerging from the yoke (2) on one face (2c) thereof perpendicular to the injector by means of a flange (3) spaced from the face (2c) and fixed to the yoke (2) by two screws (5) traversing perpendicularly this face (2c), two opposite bosses (3a) of the flange, turned towards the face (2c), being applied to two bearing zones at least diametrically opposite (6) of the injector (1), characterized in that that the bearing zones are formed in a recess (6) opening on the periphery of a cylindrical portion (4) of the injector (1) and receiving an intermediate piece (7) partially emerging from the recess (6) and in that each boss (3a) of the flange (3), external to the cylindrical portion (4) of the injector (1), is applied on a   emergent part of the intermediate piece (7).   2. Device according to claim 1, characterized in that the aforementioned recess is a peripheral groove (6) and the two bearing zones are interconnected to form   a circular support zone for the intermediate piece (7).   3. Device according to claim 2, characterized in that the intermediate piece consists of a rod in elastic metal (7).   4. Device according to one of the claims   preceding, characterized in that the two aforesaid bosses (3a) are interconnected by forming a circular support base (3a) of the flange (3) on the two support zones of the injector (1).   5. Device according to claim 3 or 4, characterized in that a ring (8) is interposed between the ring (7) and the flange (3). 7 2741396   6. Device according to claim 4, characterized in that the support base (3a) of the flange (3) comprises a   chamfer (3b) cooperating with the ring (7).   7. Device according to claim 5, characterized in that the ring (8) comprises a chamfer cooperating with the ring (7).   8. Device according to claim 1, characterized in that each bearing zone is formed in a radial recess consisting of a blind hole receiving a pin (9).   supporting a corresponding boss (3a) of the flange (3).   9. Device according to one of the claims   previous, characterized in that the injector (1) is held at its lower part (la) supported, by the flange (3), on an inner face of the yoke (2) by   via a sealing washer (R).