FR2654777A1 - FUEL SUPPLY DEVICE FOR AN INTERNAL COMBUSTION ENGINE COMPRISING A COVER MADE OF PLASTIC MATERIAL. - Google Patents

Abstract

The device according to the invention essentially comprises a body (1) capable of being fixed to the suction manifold of the engine and in which is hollowed a duct (2) for supplying the mixture, the passage section of which is controlled by a valve. butterfly valve and a cover (3) fixed to the body itself, to which are connected at least an electromagnetically actuated fuel metering and spraying valve (5) and a fuel pressure regulator supplied to the valve itself. According to the invention, the aforementioned cover is made of a thermoformable plastic material and the fuel metering and spraying valve (5) and the pressure regulator (6) are fixed to the cover itself by means of ratchet fastening means.

Description

The present invention relates to a fuel supply device

  for an internal combustion engine, of the type comprising an electromagnetically actuated fuel metering and spraying valve, capable of supplying a predetermined quantity of fuel in a duct

air to form the mixture.

  As is known, devices of this type essentially comprise a body capable of being fixed to the suction manifold of the engine and in which is hollowed out a mixture supply duct, the passage section of which is controlled by a butterfly valve. These 'devices further comprise a cover connected to the aforementioned body and in which is hollowed out an air inlet duct which opens into the mixture supply duct; to this cover are fixed an electromagnetically actuated fuel metering and spraying valve, capable of supplying fuel to the air duct to form the mixture and a pressure regulator making it possible to maintain the pressure of the fuel substantially constant fuel supplied to the metering and spraying valve Normally, this device also includes an air temperature sensor, fixed to the cover itself and comprising a base from which protrudes a temperature-sensitive element and a protection element against sensitive element, U-shaped. The fuel metering and spraying valve is fixed in a first circular seat of an annular support element placed in the center of said air duct and supported by two radial crosspieces The regulator pressure includes many bodies attached to the cover with screws; in particular this regulator comprises a deformable membrane which is fixed in a second seat of the cover by means of a cap and to which a shutter member is connected, making it possible to control the passage of the fuel between an inlet hole and an outlet hole. In the aforementioned cover is dug a first fuel conduit, which connects a fuel inlet connection to said first seat and a second fuel conduit which connects the first seat to the second, these conduits, of circular section, pass through the aforementioned crosspieces and are inclined with respect to the axis

of the first seat.

  Feeding devices of type briefly

  described have many disadvantages.

  Above all, the operations which are necessary for the construction of the regulator cover are numerous and difficult to execute: in fact, this cover, which has a very complex shape, is constructed from a metallic material, normally an alloy of aluminum, using die-casting techniques To obtain the completely finished cover, many operations to remove material are necessary, such as milling, drilling and related operations, necessary to remove burrs and to clean adequately cover surfaces. In addition, long and complex assembly operations are necessary, in particular for fixing the fuel metering and spraying valve, the pressure regulator and the temperature sensor to the cover; indeed, the fuel metering and spraying valve and the temperature sensor are fixed to the cover, using threaded members, while the pressure regulator requires more complicated mounting operations because it is necessary to have some of the organs of which it is constituted, for example the membrane, in suitable seats of the cover and then effecting the fixing, by means of screws, to the cover itself of the other bodies of the regulator. In addition, due to the complexity of the above-mentioned mounting operations, the device cannot be mounted automatically using the modalities normally

followed by these types of mounting.

  Then there is the fact that the methods of forming by pressure molding of the cover very often produce defective parts, because of the porosity which is observed in certain areas of the material. Finally, the device proves to be very costly. high due not only to the length and complexity of the assembly operations, but also to the high cost of the equipment necessary for the construction of the cover by means of the die-casting technology mentioned first: indeed, it is well known that the duration of

  molds used with this technology is rather weak.

  The weight of the device turns out to be rather high because it is constructed solely by the use of metallic materials. The object of the present invention is to provide a fuel supply device of the type briefly described, by means of which the

disadvantages listed.

  This object is achieved thanks to a supply device for an internal combustion engine, essentially comprising: a body capable of being fixed to the suction manifold of the engine and in which a supply duct for mixing the hollow is hollowed out, the passage section of which is controlled by a butterfly valve; a cover fixed to said body and in which is hollowed out an air inlet duct which opens into said mixture supply duct and to which are fixed an electromagnetically actuated fuel metering and spraying valve, capable of performing the supply of fuel to said air duct to form said mixture, a pressure regulator for keeping the pressure of the fuel supplied to said valve substantially constant and an air temperature sensor comprising a base from which an element projects temperature sensitive and a protective element of the sensitive element, U-shaped; said valve being fixed in a first circular seat of an annular support element arranged in the center of said air duct and supported by two radial crosspieces; said pressure regulator essentially comprising a cylindrical casing provided with a collar and a bottom wall in which at least one fuel inlet hole is hollowed out and to which a fuel outlet connection is fixed, said pressure regulator comprising a deformable membrane to which is attached a shutter member capable of controlling the passage of fuel between said inlet hole and said outlet connection and being supported by a second circular seat disposed on one side relative to said support element of annular shape; in said cover being hollowed out a first fuel conduit, which connects a fuel inlet connection to said first seat and a second fuel conduit which connects said first seat to said second seat, said two conduits passing through said sleepers and being inclined with respect to to the axis of said first seat; characterized by the fact that: said cover is made of thermoformable plastic: said valve being fixed in said first seat by means of first ratchet mounting means; said pressure regulator being fixed in said second seat by means of second ratchet mounting means and said temperature sensor being fixed on said cover by means of third mounting means

pawl.

  The supply device according to the invention will be

  better understood on reading the following description

  of a particular embodiment of the invention, made without implied limitation and with reference to the appended drawings, in which: FIG. 1 illustrates the fundamental organs of the device, some being shown in section and others in side view and separated from the previous ones; Figure 2 shows a plan view of the device cover; Figures 3 to 5 show a plan view and two perspective views of the mounting means of the metering valve and fuel spray which is provided with the device; Figures 6 and 7 show, respectively in perspective and in section, the mounting means of the pressure regulator; FIG. 8 represents a section of a part of the cover of the device in correspondence of which the temperature sensor is mounted; Figures 9 and 10 show perspective views, partially cut away, of the mounting means

of the temperature sensor.

  The fuel supply device according to the invention essentially comprises a body 1 (FIG. 1), capable of being fixed to the suction manifold of the engine and in which a conduit 2 is hollowed out in which the mixture intended for l 'supply to the manifold itself, along this conduit being inserted a butterfly valve (not shown), capable of controlling the passage section of the conduit itself. The device further comprises a cover 3 fixed to the body, in any suitable manner, and in which is hollowed out an air inlet duct 4 (FIG. 2) which opens into the mixture supply duct 2; to the cover is fixed an electromagnetic actuation fuel metering and spraying valve 5 (FIG. 1), well known per se and capable of supplying fuel to the air duct 4 to form said mixture, as well as a pressure regulator 6, also known per se, making it possible to maintain the pressure of the fuel supplied to the valve substantially constant The valve 5 is arranged in a first circular seat 7 which is hollowed out inside a support element for annular shape 8 which is arranged in the center of the air duct 4 and supported by two radial crosspieces 9 (Figures 1 and 2) Suitably, the pressure regulator 6 is of the type described in the Italian patent application filed by the applicant under number 68054-A / 88; this regulator essentially comprises a cylindrical casing 12 provided with a collar 13 and a bottom wall 14 in which at least one fuel inlet hole 15 is hollowed out and to which a fuel outlet connection 16 is fixed. type well known in itself, comprises a deformable membrane (not shown) to which is fixed a shutter member capable of controlling the passage of fuel between said hole

  inlet 15 and said outlet connection 16.

  The pressure regulator 6 is housed in a second seat 17, also circular, arranged on one side by

  report to said annular support member 8.

  In said cover 3 is hollowed out a first fuel conduit 18, which connects a fuel inlet connection 19 (FIG. 2) to the first seat 7 of the valve 5, as well as a second fuel conduit 20 which connects the seat 7 at seat 17 of the pressure regulator 6; these two conduits, of circular section, cross the crosspieces 9 and are inclined relative to the axis of the seat

  7 of valve 5, as can be seen in FIG. 1.

  One end of the conduit 18 is capable of being closed off

by a plug 19 a.

  According to the invention, the cover 1 is made of thermoformable plastic material and preferably using the injection molding technique. Consequently, the cover can be obtained completely finished, in a single molding operation and there is no need to no subsequent mechanical operation to remove material or other treatments to make it directly usable for

mounting on the device.

  Furthermore, according to the invention, the fuel metering and spraying valve 5 is fixed in the corresponding seat 7 by means of first ratchet mounting means, designated as a whole by 24 and visible in FIGS. 1,3 4 and 5; the pressure regulator 6 is mounted in the respective seat 17 by means of second ratchet mounting means, designated as a whole

  by 25 and shown in Figures 1, 6 and 7.

  Also forming an appropriate part of the device according to the invention, an air temperature sensor 26 makes it possible to measure, in a known manner, the temperature of the air supplying the suction duct 4. This sensor essentially comprises a flat base 27 from which protrude a temperature sensitive element 28 and a protective element 29, capable of protecting the sensitive element 28, made substantially in

  U shape, as seen in Figures 9 and 10.

  Also according to the invention, the air temperature sensor 26 is fixed to the cover 3 by means of

  ratchet assembly, designated as a whole by 30.

  On the seat 7 of the support element 8 (FIG. 1) is hollowed out a connection zone 34 making it possible to facilitate the passage of the fuel from the seat 7 to the second fuel conduit 20. This connection zone is also formed during the molding of the cover 3: for this purpose, the distance between the axis of the duct 20 and the upper edge 35 of the support element 8, the distance which has been designated by the letter a in FIG. 1, is at least equal to the diameter of the duct even If these geometrical conditions are satisfied, it is obvious that the connection zone 34 can be generated by the end surface of a core forming part of the mold for forming the cover 3 which, during the opening of the mold, moves substantially in the direction of the axis of the conduit; it is obvious to those skilled in the art of molding that if the geometrical condition mentioned first is satisfied, the aforementioned core can have a substantially large cross section to resist the stresses to which it

  is exposed during lid molding operations.

  According to the invention, the cover 3 comprises a projection of tubular shape 36 (FIG. 1), starting from the upper surface 37 (FIG. 2) of the cover itself, a wall 38 which delimits the projection 36 in the lower part and a second projection 39 of tubular shape, starting from the wall 38; the projection 36 and the wall 38 defining the seat 17, while the projection 39 is capable of accommodating said outlet connection 16 of the regulator

pressure.

  An annular packing element 40 is interposed between the exterior surface of said casing 12 of the pressure regulator 6 and the seat and an additional lining element 41 is interposed between the exterior surface of the outlet connection 16 and the surface.

interior of said projection 39.

  The ratchet mounting means 24, making it possible to fix the valve 5 on the cover 1, comprise two teeth 45 projecting radially from the external surface of the support element 8 and a spring 46 having substantially an annular shape and comprising two sections central 47 (Figures 1, 3 4 and 5) from which start two end sections 48, U-shaped, each of them being perpendicular to the central sections and arranged so as to hang on a corresponding tooth 45 . The ratchet mounting means 25 of the pressure regulator 6 comprise two teeth 49 (FIG. 7), projecting radially from the external surface of the projection 36 of tubular shape, and a ring 50 (FIG. 6) capable of bearing on the collar 13 of the regulator casing, the ring 50 being provided with two hook-shaped fins 51 and capable of bearing on the teeth 49, as seen on the

Figures 6 and 7.

  The ring 50 and the fins 51 are constructed of a

  single piece from a metal strip.

  The temperature sensor 26 is fixed to the cover 3 in correspondence with the buttonhole 52 (FIG. 2); the upper surface 53 of the base 27 bears substantially against the lower surface of the cover, as can be seen in FIGS. 8 and 9, while the sensitive element 28 and the protective element 29 pass through the buttonhole 52, projecting from the upper surface 37 of the cover 3 The means for mounting the temperature sensor 26 on the cover essentially comprise, according to the embodiment of FIG. 9, two pins 54, each of which passes through a corresponding hole in the cover (FIG. 8 ); on the upper end of each spike is hollowed out a head made elastically deformable by a notch 56; the size of the head is greater than that of the pin, so that it can pass through the corresponding hole while being elastically deformed and can snap onto the upper edge of this hole so as to block the base 27 on the cover , as seen in Figure 9. According to an alternative embodiment of these mounting means, shown in Figure 10, the protective element 29 is separated substantially into two elastically deformable arms by means of a notch 57; in addition, in correspondence with the root zone of each of these arms is hollowed out a cavity 58 susceptible of mating

  with a corresponding projection 59 of the cover 3.

  The procedure for mounting the supply device according to the invention is as follows: The spring 46 is housed in the seat 60 of the valve and the latter is inserted into the corresponding seat 7, so that the end section 48 of the spring 46 presses on the teeth 45 and that, as a result of the exercise of an adequate force on the spring itself, these end sections are elastically deformed under the action of the teeth 45, until the very sections snap below the teeth; in this position, it is impossible for the valve 5 to leave the seat 7

  as seen in Figures 3, 4 and 5.

  The pressure regulator 6 is mounted by inserting its outlet connection 16 inside the hole 61 of the projection 39 and part of the casing 12 inside the seat 17, until the collar 13 it bears against the upper surface of the projection 36, as

  it can be seen in FIG. 7 The ring 50 is moved over

  above the collar itself and the fins 51 are elastically deformed, making them snap under the teeth 49, as shown in FIGS. 6 and 7. Finally, the temperature sensor 26 is mounted by inserting the sensitive element 28 and the protective element 29 inside the buttonhole 52; by exerting an appropriate force on the base 27, an elastic deformation is caused either of the heads 55 of the pins 54 (FIG. 9), or of the two arms of the protective element 29 (FIG. 10), until they click into place heads or arms respectively above surface 37 or

against projections 59.

  Suitably, an elastically deformable element, for example a spring 62 can be arranged

  between the base 27 and the cover 3 (Figure 9).

  All the assembly operations described above can be carried out automatically, using appropriate machines and devices. The group thus obtained by mounting the valve 5, the pressure regulator 6 and the temperature sensor 26 is then

mounted on the body 1 (Figure 1).

  It is obvious that the operations necessary for the construction of the device according to the invention are few

  many and very simple: indeed, as described above

  above, the cover 3 is obtained completely finished by means of a hot forming operation Consequently, no subsequent mechanical machining operation with removal of material is necessary, no treatment for cleaning certain parts or eliminating the

machining burrs.

  In addition, the material of the cover 3 is-

  practically homogeneous, unlike that which is the case with covers constructed of metallic materials which, very often, must be discarded by the presence of porosity inside the same material Furthermore, the cover 3 can be produced at a significantly low cost due to the high lifetime of the molds used in the forming process and the reduced molding times which are necessary for the forming of these parts; even the weight of the device thus obtained is greatly reduced, the specific weight of the material being very low Finally, the operations described above for mounting the valve 5, the pressure regulator 6 and the temperature sensor 26 which are described below - above can be carried out in very short times and by means of the use of machines and devices of automatic assembly. Of course, the present invention is not limited to the embodiments described and shown, but the various parts of the supply device according to the invention are susceptible of numerous variants of shape and arrangement without that one being

  departs from the spirit of the invention.

Claims (5)

  1 Fuel supply device for an internal combustion engine, essentially comprising: a body (1) capable of being fixed to the intake manifold of the engine and in which a conduit (2) for supplying mixture to the manifold is hollowed out , the passage section of which is controlled by a butterfly valve; a cover (3) fixed to said body and in which an air intake duct (4) is hollowed to open into said mixture supply duct (2) and to which are fixed a fuel metering and spraying valve electromagnetically actuated (5) capable of supplying fuel to said air duct (4) to form said mixture, a pressure regulator (6) making it possible to maintain the pressure of the fuel supplied to said valve substantially constant and an air temperature sensor (26) comprising a base (27) from which protrudes a temperature-sensitive element (28) and a protection element (29) of the sensitive element, U-shaped; said valve being fixed in a first circular seat (7) of a support element (8) of annular shape disposed in the center of said air duct (2) and supported by two radial crosspieces (9); said pressure regulator (6) essentially comprising a cylindrical casing (12) provided with a collar (13) and a bottom wall (14) in which is hollowed out at least one fuel inlet hole (15) and to which is fixed a fuel outlet connection (16), said pressure regulator (6) comprising a deformable membrane to which is fixed a shutter member capable of controlling the passage of fuel between said inlet hole (15) and said connection outlet (16) and being supported by a second circular seat (17) disposed on one side with respect to said annular support member (8); on said cover being hollowed out a first fuel conduit (18) which connects a fuel inlet connection (19) to said first seat (7) and a second fuel conduit (20) which connects said first seat (7) to said second seat (17), said two conduits passing through said crosspieces (9) and being inclined relative to the axis of said first seat (7); characterized by the fact that: said cover (3) is made of thermoformable plastic: said valve (6) being fixed in said first seat (7) by means of first ratchet mounting means (24);   said pressure regulator (6) being fixed in said second seat (17) by means of second ratchet mounting means (25) and said temperature sensor (26) being fixed on said cover by means of third ratchet mounting means . 2 supply device according to claim 1, characterized in that the distance between the axis of said second conduit (20) and the upper edge (35) of said first seat (7) is at least equal to the diameter of the conduit itself.  3 supply device according to claim 1 or 2, characterized in that said cover (3) comprises a first projection (36) of tubular shape extending from the upper surface (37) of the body itself, a bottom wall (38 ) which delimits at the bottom said annular projection, and a second projection (39) starting from said bottom wall (38), said first projection and said bottom wall defining said second seat (17) and said second projection (39) being capable of accommodating said outlet connection (16) of said pressure regulator.   4 supply device according to claim 3, characterized in that it comprises a first annular lining element (40) interposed between the outer surface of said envelope (12) and the inner surface of said first projection (36) and a second annular packing element (41), interposed between the outer surface of said outlet connection (16) and the   inner surface of said second projection (39).   Feeding device according to any one   of the preceding claims, characterized in that   that said first ratchet mounting means (24) comprise at least one tooth (45) projecting radially from the external surface of said support element (8) and a spring (46) comprising at least one first section (47) capable of bear on a surface (60) of said valve and a second section (48) capable of hooking by snap-fastening with one of said teeth.   6 Feeding device according to claim, characterized in that it includes two of said teeth (45) and said spring (46) having an annular shape and comprising two central sections (47) from which two sections of end (48) U-shaped. each of them being perpendicular to said central sections and arranged so as to hang on a corresponding tooth. 7 Feeding device according to any moon   of the preceding claims, characterized in that   that said second ratchet mounting means (25) comprise two teeth (49) projecting radially from the external surface of said first projection (36) of tubular shape, a ring (50) capable of bearing on said collar (13) of said pressure regulator casing, said ring being provided with two hook-shaped fins (51) capable of build on said teeth.   8 Feeding device according to any one   of the preceding claims, characterized in that   that said third ratchet mounting means (30) comprise at least two spikes (54) elastically deformable and projecting from said base (27); each of said pins being provided with at least one tooth (55) capable of bearing on a projection of said cover. 9 Feeding device according to claim 8, characterized in that each of said pins (54) has a head (55) provided with a slot (56)   likely to produce a pair of teeth.   Feeding device according to claim 8, characterized in that each of said pins (54) is produced by means of a section of said protective element (29) of the temperature sensor, made deformable by means of a notch (57) of the element of protection itself.