Direct injection fuel pump for internal combustion engine

Abstract

A fuel pump comprises a pump body (2) and a valve (1). The valve (1) comprises: a sleeve (11) of substantially tubular shape extending along an actuation axis (A) so as to define a housing for a coil (12); a tubular body (10) having the same axis as the sleeve (11) and being partially housed within the bore (20) of the pump body (2). An electromagnetic coil (12) of annular shape is housed in the sleeve (11) and surrounds the tubular body (10) centered on said actuation axis (A), and a coil support (13) holds the coil (12) and is inserted in a first end (111) of the sleeve (11). According to the invention, the valve comprises a first sealing device (3) comprising an annular first seal (31) between the coil support (13) and the sleeve (11), which is supported on one side on a sleeve seat (32) provided by the sleeve (11) at the first end (111) and on the other side on a carrier seat (33) provided by the coil support (13).

Description

Technical Field

[0001] The present invention relates to a direct injection fuel pump for an internal combustion engine and more particularly to a valve in such a pump. Background Art

[0002] Fuel systems in modern gasoline-powered internal combustion engines, particularly those in the automotive market, use gasoline direct injection, where fuel injectors are used to inject fuel directly into the combustion chambers of the engine. In such direct injection systems, fuel from a fuel tank is provided by a low-pressure fuel pump integrated into the fuel tank. This low-pressure pump is typically electric and provides power to a high-pressure pump, which typically includes a pump piston that is movable in a pump body. The pump piston is actuated by the crankshaft of the internal combustion engine in order to raise the pressure of the fuel in the pumping chamber of the pump body. The high-pressure fuel is then distributed to the injectors, which control the injection of the fuel directly into the combustion chambers of the engine.

[0003] An intake valve assembly arranged between a fuel inlet from a low-pressure pump and a pumping chamber is also provided. The intake valve assembly comprises in particular a solenoid actuator which makes it possible to control the opening or closing of the fuel inlet.

[0004] Document EP3715619 shows such a high-pressure pump equipped with a solenoid actuator. The solenoid actuator comprises: a tubular body in which the bobbin is mounted in a movable manner in the direction of the actuator; a pole piece, which is fixedly accommodated in the tubular body; a coil, which is centered outside the tubular body to generate a magnetic field in the pole piece and attract the bobbin against the spring; and a coil ring, which is also placed around the tubular body to direct the magnetic field towards the pole piece. The actuator is accommodated in a sleeve of generally tubular shape and fixed to the body of the pump by welding.

[0005] The coil and the coil ring are integrated into a coil support made of synthetic material and an electrical connector is integrated to power the coil. The assembly is mounted by forced insertion into the sleeve, the tightening being ensured by screwing between the ring and the sleeve. The axial position is determined by the shoulder of the sleeve against which the support abuts during forced insertion. The sleeve has a notch for the passage of the connector.

[0006] It can be seen that this installation has drawbacks in terms of corrosion resistance. In fact, water can enter through the passage between the ring and the sleeve and there is a risk of damaging the tubular body in particular, making it necessary to provide it with protection against corrosion. Water can also enter through the joint between the sleeve and the body of the pump when the weld is not waterproofed. Summary of the invention

[0007] The object of the present invention is to solve the problems of the prior art, in particular to improve the ease of installation while suppressing the risk of corrosion.

[0008] In view of these objects, the present invention relates to a fuel pump according to claim 1 .

[0009] The fuel pump includes a pump body and a valve, the valve including: a sleeve of generally tubular shape, the sleeve being fixed to the pump body and extending along the actuation axis so as to define a housing for the coil; a tubular body having the same axis as the sleeve, the tubular body being partially accommodated in the hole of the pump body; an annular electromagnetic coil, the electromagnetic coil being accommodated in the sleeve and surrounding the tubular body centered on the actuation axis; a coil support, the coil support holding the coil and being inserted into the first end of the sleeve, characterized in that the valve includes a first sealing device, the first sealing device including an annular first seal between the coil support and the sleeve bearing, the first sealing device being located on the one hand on a sleeve seat held by the sleeve at the first end, and on the other hand on a support seat held by the coil support.

[0010] By providing the first sealing means, water is prevented from penetrating between the first end of the sleeve and the coil support. This prevents the tubular body from being exposed to corrosion risks. Since the seal and the seat have an annular shape, the orientation of the coil support relative to the sleeve is irrelevant. Thus, the installation is simplified because it does not require a precise orientation of the coil support relative to the sleeve which no longer comprises a recess.

[0011] According to one embodiment, the support seat is held by a skirt integrated into the coil support, the skirt having an annular shape and covering the first end of the sleeve, the sleeve seat being held on the outer diameter of the sleeve. The contact of the seal on the skirt is therefore radial. The compression of the seal on the seat does not cause any resultant force for the placement of the coil support, but only internal forces, which tend to expand the skirt and tend to compress the sleeve. In addition, the seat of the sleeve moves away from the passage of the ring during the forced insertion of the sleeve. This avoids the risk of damaging the seat during this operation of inserting the ring.

[0012] According to another embodiment, the sleeve seat is located at the end of the sleeve and the support seat is held by the shoulder of the coil support. The seats are thus facing each other and clamp the seal in the axial direction. The manufacture of these seats is simple. The compression force of the seal is provided during the forced insertion of the ring into the sleeve.

[0013] According to one improvement, the valve comprises an axial stop to limit the travel of the coil support in the actuation direction. Thus, during forced insertion of the support, the stop determines the position at which the insertion stops. The compression of the seal is determined by the geometry of the piece, in particular by the axial position of the seat relative to the stop.

[0014] According to one improvement, the sleeve seat is located in an internal notch at the first end of the sleeve. Thus, the notch leaves a collar at the first end of the sleeve, which surrounds the seal and protects the seal from physical impact.

[0015] According to one refinement, the coil support comprises a step-down covering the first end of the sleeve. This forms a barrier between the step-down and the first end of the sleeve, which protects the first seal, in particular from physical impacts.

[0016] According to one constructional arrangement, the first seal is in the form of an O-ring. This type of seal is widely available and provides an excellent seal in static use as here.

[0017] According to one constructional arrangement, the coil support has a bearing surface opposite the coil and substantially perpendicular to the actuation axis.

[0018] According to a variant, the pump is characterized in that it comprises a second sealing device comprising a second seal housed in a groove surrounding the tubular body and bearing both against the pump body and against the sleeve at the outlet of the orifice. This prevents a second potential passage of water towards the tubular body at the junction of the sleeve on the body of the pump. The second seal forms a junction and a barrier between the sleeve and the body of the pump.

[0019] According to one construction arrangement, the second seal has a four-lobed cross section. This increases the contact line between the seal and the component, which increases the barrier against the passage of water.

[0020] According to one constructional arrangement, the groove is formed at a second end of the sleeve opposite to the first end.

[0021] According to an improvement, the sleeve is fixed to the pump body by welding. The addition of the seal does not require consideration of the assembly technology between the pump body and the sleeve. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present invention will be better understood and other features and advantages will appear when reading the following description with reference to the accompanying drawings, in which:

[0023] Figure 1 is a partial cross-sectional view of a pump according to a first embodiment of the present invention;

[0024] Figure 2 is a perspective view of a coil support for a pump according to a first embodiment;

[0025] Figure 3 is a pump according to the second embodiment similar to Figure 1 's view;

[0026] Figure 4 is a pump according to the third embodiment similar to Figure 1 of the view. DETAILED DESCRIPTION

[0027] A fuel pump according to a first embodiment of the present invention is Figure 1 and Figure 2 The pump comprises a valve 1 fixed to a pump body 2. The active part of the valve is not yet shown and is intended to be inserted into a tubular body 10, which is partially shown. The tubular body 10 extends along the actuation axis A in a hole 20 of the pump body 2 and protrudes from the pump body 2. It comprises a closed end 101 located outside the pump body 2.

[0028] The valve 1 comprises a sleeve 11 having a generally tubular shape and extending along the actuation axis A so as to define a housing for the coil. The sleeve 11 comprises an inner ring 110 , the inner diameter of which is adjusted to the outer diameter of the protruding portion of the tubular body 10 .

[0029] The valve 1 further comprises: an annular electromagnetic coil 12 which is housed in the sleeve 11 and surrounds the tubular body 10 centered on the actuation axis A; and a coil support 13 which holds the coil 12 and is inserted into the first end 111 of the sleeve 11 and abuts against the ring 110. The coil support 13 is Figure 2 12 and 13. The coil support 13 includes a metal ring 14 attached to the coil 12 and used to guide the magnetic flux generated by the coil 12. The ring 14 is also arranged to be force-fitted in the sleeve 11 in the housing for the coil, and thus the coil support 13 is kept in place. The sleeve has a chamfer 112 for entering the housing of the coil at the first end 111. The coil support 13 also includes an electrical connector 130 with at least two plugs 131, which are electrically connected to the coil 12 by conductors not shown. The coil support 13 is made by molding thermoplastic material in a mold with the ring 14, the plug 131, the conductor and the coil 12 in place. These parts are then at least partially embedded in the hardened thermoplastic material after cooling in the mold.

[0030] The coil support 13 has a bearing surface 132 opposite the coil 12 and substantially perpendicular to the actuation axis A. In this embodiment, the bearing surface 132 has radial ribs 133 , making it possible to limit the amount of material of the bearing surface 132 .

[0031] The sleeve 11 is fixed to the pump body 2 by a continuous or intermittent weld S at the outer periphery of the second end of the sleeve 11 .

[0032] The valve 1 comprises a first sealing means 3 comprising a first O-ring, thus an annular seal 31 between the coil support 13 and the sleeve 11, bearing, on the one hand, on a sleeve seat 32 held by the sleeve 11 at the first end 111, and, on the other hand, on a support seat 33 held by the coil support 13. The support seat 33 is held by a skirt 134 integrated into the coil support 13, having an annular shape and covering the first end 111 of the sleeve 11. More specifically, the support seat 33 is held on the inner cylindrical surface of the skirt 134. The sleeve seat 32 is held on the outer diameter of the sleeve 11, at the first end 111, in an outer notch.

[0033] The pump also comprises a second sealing device 4 comprising a second seal 42 housed in a groove 41 retained by the sleeve 11 at a second end of the sleeve 11 opposite to the first end 111 and surrounding the tubular body 10 and bearing both against the pump body 2 and against the ring 110 of the sleeve 11 at the outlet of the orifice 20. The second seal 42 has a four-lobed cross section.

[0034] The production of the pump will now be described in conjunction with the valve 1 .

[0035] The tubular body 10 containing the elements of the valve 1 is inserted into the hole 20 of the pump body 2. The second seal 42 is inserted onto the tubular body 10 and pushed against the pump body 2, and the sleeve 11 is inserted onto the tubular body 10 while being centered by the ring 110. The second seal 42 abuts both against the pump body 2 and against the ring 110 of the sleeve 11, which is welded to the outer corner where it joins the pump body 2.

[0036] Then, the first seal 31 is placed inside the skirt 134 or on the first end 111 of the sleeve 11, the coil support 13 is introduced into the sleeve 11 and a significant force is applied to the bearing surface 132 of the support in the direction of the actuation axis A until the support comes into contact with the ring 110 of the sleeve 11. The ring 14 is then forced into the sleeve 11, which is facilitated by the chamfer 112, and the coil support 13 is fixed to the sleeve 11. The first seal 31 is located between the support seat 33 and the sleeve seat 32 and provides a seal between the two parts 11, 13, being in substantially radial contact with the seats 32, 33.

[0037] In a second embodiment, if Figure 3As shown, the valve 1 ' differs from the first embodiment in that the sleeve seat 32' is located at the end of the sleeve 11' and the support seat 33' is retained by the shoulder 135 of the coil support 13'. The contact between the first seal 31 ' and the seat 32', 33' is essentially axial. The installation sequence is essentially the same as in the first embodiment, except that the first seal 31 ' is initially placed against the shoulder 135 of the support 13'. The compression of the first seal 31 ' is determined by the position that the coil support 13' can reach against the ring 110 of the sleeve 11 '.

[0038] In a variant, the coil support 13' has a step 136 covering the first end 111' of the sleeve 11'. Figure 3 As shown by the dotted line in FIG. 136 , there is no contact between the step 136 and the sleeve 11 ′.

[0039] In a third embodiment, if Figure 4 As shown, the valve 1 differs from the first embodiment in that the sleeve seat 32" is in an internal groove 34 at the first end 111" of the sleeve 11". The contact between the first seal 31" and the seat 32", 33" is essentially axial. The installation sequence is essentially the same as in the first embodiment, except that the first seal 31' is initially placed against the shoulder of the coil support 13". The compression of the first seal 31" is determined by the position that the coil support 13" can reach against the ring 110 of the sleeve 11". In a variant, the coil support 13" includes a step 136" covering the first end 111" of the sleeve 11", as shown Figure 4 As shown by the dotted line in FIG. 136 , there is no contact between the step 136 ″ and the sleeve 11 ″.

Claims

1. A fuel pump, comprising a pump body (2) and a valve (1), wherein the valve (1) comprises: A sleeve (11) of generally tubular shape, the sleeve (11) being fixed to the pump body (2) and extending along the actuation axis (A) so as to define a housing for a coil (12); a tubular body (10) having the same axis as the sleeve (11) and being partially received in a hole (20) of the pump body (2); an electromagnetic coil (12) of annular shape, the electromagnetic coil being received in the sleeve (11) and being centered around the tubular body (10) with the actuation axis (A); a coil support (13) The invention relates to a valve having a first sealing device (3), wherein the first sealing device (3) comprises an annular first sealing member (31) between the coil support member (13) and the sleeve (11), the annular first sealing member (31) being supported on one hand on a sleeve seat (32) held by the sleeve (11) at the first end (111) and on the other hand on a support seat (33) held by the coil support member (13).

2. The pump according to claim 1, wherein The support seat (33) is held by a skirt (134) integrated into the coil support (13), the skirt (134) having an annular shape and covering the first end (111) of the sleeve (11), and the sleeve seat (32) is held on the outer diameter of the sleeve (11).

3. The pump according to claim 1, wherein The sleeve seat (32) is located at the end of the sleeve (11), and the support seat (33) is held by the shoulder of the coil support (13).

4. The pump according to claim 3, wherein: The sleeve seat (32) is located in an internal notch at the first end (111) of the sleeve (11).

5. The pump according to claim 3 or 4, characterized in that The pump comprises an axial stop to limit the travel of the coil support (13) in the direction of the actuation axis (A).

6. A pump according to claims 3 to 5, wherein The coil support (13) includes a step (136) covering the first end (111) of the sleeve (11).

7. A pump according to any one of the preceding claims, wherein The first sealing member (31) is in the shape of an O-ring.

8. A pump according to any one of the preceding claims, wherein The coil support (13) has a bearing surface (132) opposite to the coil (12) and substantially perpendicular to the actuation axis (A).

9. A pump according to any one of the preceding claims, characterised in that The pump comprises a second sealing device (4) comprising a second seal (42) housed in a groove (41) surrounding the tubular body (10) and bearing both against the pump body (2) and against the sleeve (11) at the outlet of the orifice (20).

10. The pump according to claim 9, wherein The second seal (42) has a four-lobed cross-section.

11. A pump according to claims 9 to 10, wherein The groove is formed at a second end of the sleeve (11) opposite to the first end (111).

12. A pump according to any one of the preceding claims, wherein The sleeve (11) is fixed to the pump body (2) via a welding portion (S).

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