Direct-injection fuel pump for internal combustion engines

Abstract

A fuel pump comprises a pump body (2) and a valve (1). The valve (1) comprises a sleeve (11) of substantially tubular shape and extends along an axis of actuation (A) so as to define a housing for a coil (12), a tubular body (10) having the same axis as the sleeve (11) being partially housed inside a bore (20) of the pump body (2). An electromagnetic coil (12) of annular shape is housed in the sleeve (11) and centred on said axis of actuation (A) around the tubular body (10), a coil support (13) holds the coil (12) and is inserted into a first end (111) of the sleeve (11). The valve comprises first sealing means (3) comprising an annular first seal (31) between the coil support (13) and the sleeve (11) bearing, on the one hand, on a sleeve seat (32) presented by the sleeve (11) at the first end (111) and, on the other hand, on a support seat (33) presented by the coil support (13).

Description

[0001] P -DELPHI-369 / WO

[0002] Fuel pump for direct fuel injection for internal combustion engines

[0003] Technical field

[0004] The invention relates to a fuel pump for direct fuel injection for internal combustion engines. More particularly, it relates to a valve in such a pump.

[0005] Prior art

[0006] Fuel systems in modern gasoline-powered internal combustion engines, particularly those for the automotive market, utilize direct gasoline injection in which fuel injectors are used to inject fuel directly into the engine's combustion chambers. In such direct injection systems, fuel from the tank is supplied by a low-pressure fuel pump integrated into the tank. This low-pressure pump is usually electric and powers a high-pressure pump that typically includes a movable pump piston within a pump housing. The pump piston is actuated by a camshaft of the internal combustion engine to raise the fuel pressure in a pump chamber of the pump housing. The high-pressure fuel is then delivered to the injectors, which control the injection of fuel directly into the engine's combustion chamber.

[0007] An inlet valve assembly is also provided between a fuel inlet from the low pressure pump and the pumping chamber. The inlet valve assembly includes in particular a solenoid actuator which is used to control the opening or closing of the fuel inlet.

[0008] Document EP 3 715 619 shows such a high pressure pump equipped with a solenoid actuator. The solenoid actuator comprises a tubular body in which a slide is mounted movable in an actuator direction, a pole piece fixedly housed in the tubular body, a coil centered on the tubular body outside it to create a magnetic field in the pole piece and attract the slide against a spring, and a coil ring also placed around the tubular body to orient the magnetic field towards the pole piece. The actuator is housed in a sleeve of substantially tubular shape and fixed by welding to a body of the pump.

[0009] The coil and coil ring are integrated into a synthetic coil holder incorporating an electrical connector to power the coil. This assembly is force-fitted into the sleeve, with the fixing being ensured by the clamping between the ring and the sleeve. The axial position is determined by a shoulder on the sleeve against which the holder abuts during force-fitting. The sleeve has a notch for the connector to pass through.

[0010] It is noted that this assembly has defects with regard to corrosion resistance. Indeed, water can enter through a passage between the ring and the sleeve and risks damaging the tubular body in particular, requiring it to be provided with protection against corrosion. Water can also enter through the junction between the sleeve and the pump body when the weld is not made to be watertight.

[0011] Statement of the invention

[0012] The invention aims to remedy the problems of the prior art, and in particular to contain the risks of corrosion, while improving ease of assembly.

[0013] With these objectives in view, the invention provides a fuel pump according to claim 1.

[0014] The fuel pump comprises a pump body and a valve, which comprises a sleeve of substantially tubular shape, fixed on the pump body, and extending along an actuation axis so as to define a coil housing, a tubular body of the same axis as the sleeve partially housed in a bore of the pump body, an electromagnetic coil of annular shape housed in the sleeve and centered on said actuation axis around the tubular body, a coil support carrying the coil and inserted at a first end of the sleeve, characterized in that the valve comprises first sealing means comprising a first annular seal between the coil support and the sleeve bearing on the one hand on a sleeve seat carried by the sleeve at the first end and on the other hand on a support seat carried by the coil support.

[0015] By providing the first sealing means, water penetration is prevented between the first end of the sleeve and the coil support. This prevents the tubular body from being exposed to the risk of corrosion. As the seal and the seats are annular, the orientation of the coil support relative to the sleeve is irrelevant. Assembly is therefore simplified because it does not require precise orientation of the coil support relative to the sleeve, which no longer has a notch.

[0016] According to one embodiment, the support seat is carried by a skirt integrated into the coil support, of annular shape and covering the first end of the sleeve, the sleeve seat being carried on an outside diameter of the sleeve. The contact of the seal on the skirt is therefore radial. The compression of the seal on the seats does not induce any resultant force on the placement of the coil support, but only internal forces, those tending to the expansion of the skirt and those tending to the compression of the sleeve. In addition, the sleeve seat is distant from the passage of the ring during its forceful insertion into the sleeve. This avoids the risk of damaging the seat during this ring insertion operation.

[0017] According to another embodiment, the sleeve seat is at the end of the sleeve and the support seat is carried by a shoulder of the coil support. The seats are therefore opposite each other and pinch the seal in an axial direction. The production of these seats is simple. The compressive forces of the seal are provided when the ring is force-fitted into the sleeve.

[0018] According to an improvement, the valve comprises an axial stop to limit the travel of the coil holder in the actuation direction. Thus, when the holder is forcefully inserted, the stop determines the position at which the insertion is stopped. The compression of the seal is determined by the geometry of the parts, and in particular by the axial positions of the seats relative to the stop.

[0019] According to an improvement, the sleeve seat is in an internal rebate at the first end of the sleeve. Thus, the rebate leaves a collar at the first end of the sleeve, which surrounds the seal and protects it against physical attacks.

[0020] According to an improvement, the coil support has a drop covering the first end of the sleeve. This creates a baffle between the drop and the first end of the sleeve which protects the first joint, particularly against physical attacks.

[0021] According to a constructive arrangement, the first seal is an O-ring. This type of seal is widely available and allows for excellent sealing in static use as here.

[0022] According to a constructive arrangement, the coil support has a bearing face opposite the coil and substantially perpendicular to the actuation axis.

[0023] According to variants, the pump is characterized in that it comprises second sealing means comprising a second seal housed in a groove around the tubular body and bearing both against the pump body at an outlet of the bore and against the sleeve. This prevents a second potential passage of water towards the tubular body at the junction of the sleeve on the pump body. The second seal forms the junction between the sleeve and the pump body and provides a barrier.

[0024] According to a constructive arrangement, the second seal has a quadrilobe section. This multiplies the contact lines between the seal and the parts, which increases the barriers against the passage of water.

[0025] According to a constructive arrangement, the groove is made at a second end of the sleeve opposite the first end. According to an improvement, the sleeve is fixed to the pump body by welding. The addition of the seal does not compromise the assembly technique between the pump body and the sleeve.

[0026] Brief description of the figures

[0027] The invention will be better understood and other features and advantages will appear on reading the description which follows, the description making reference to the appended drawings among which:

[0028] • Figure 1 is a partial sectional view of a pump according to a first embodiment of the invention;

[0029] • Figure 2 is a perspective view of a coil support for the pump according to the first embodiment;

[0030] • figure 3 is a view similar to figure 1 of a pump according to a second embodiment;

[0031] • Figure 4 is a view similar to Figure 1 of a pump according to a third embodiment.

[0032] Detailed description

[0033] A fuel pump according to a first embodiment of the invention is partially shown in Figures 1 and 2. The pump comprises a valve 1 fixed to a pump body 2. The active part of the valve has not been shown and is intended to be inserted into a tubular body 10 shown partially. The tubular body 10 extends along an actuation axis A in a bore 20 of the pump body 2 and projects from the pump body 2. It has a closed end 101 outside the pump body 2.

[0034] The valve 1 comprises a sleeve 11 of substantially tubular shape and extending along the actuation axis A so as to define a coil housing. The sleeve 11 comprises an inner ring 110 whose inner diameter is adjusted to the outer diameter of the projecting part of the tubular body 10.

[0035] The valve 1 further comprises an annular electromagnetic coil 12 housed in the sleeve 11 and centered on the actuation axis A around the tubular body 10, and a coil support 13 carrying the coil 12 and inserted at a first end 111 of the sleeve 11 in abutment against the ring 110. The coil support 13 is shown alone in FIG. 2. The coil support 13 comprises a metal ring 14 attached to the coil 12 and serving to channel the magnetic flux generated by the coil 12. The ring 14 is further designed to be force-fitted inside the sleeve 11 in the coil housing and thus hold the coil support 13 in place. The sleeve comprises a chamfer 112 for entry into the coil housing at the first end 111. The coil support 13 further comprises an electrical connector 130 with at least two plugs 131 electrically connected to the coil 12 by conductors, not shown.The coil holder 13 is made by molding a thermoplastic material in a mold with the ring 14, the plugs 131, the conductors and the coil 12 in place. These are then at least partially embedded in the hardened thermoplastic material after cooling in the mold.

[0036] The coil support 13 has a bearing face 132 opposite the coil 12 and substantially perpendicular to the actuation axis A. The bearing face 132 has, in this embodiment, radial ribs 133 making it possible to limit the quantity of material used to produce the bearing face 132.

[0037] 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.

[0038] The valve 1 comprises first sealing means 3 comprising a first O-ring seal 31, therefore annular, between the coil support 13 and the sleeve 11 bearing on the one hand on a sleeve seat 32 carried by the sleeve 11 at the first end 111 and on the other hand on a support seat 33 carried by the coil support 13. The support seat 33 is carried by a skirt 134 integrated into the coil support 13, of annular shape and covering the first end 111 of the sleeve 11. More particularly, the support seat 33 is carried on the inner cylindrical surface of the skirt 134. The sleeve seat 32 is carried on an outer diameter of the sleeve 11, in an outer rebate at the first end 111.

[0039] The pump further comprises second sealing means 4 comprising a second seal 42 housed in a groove 41 carried by the sleeve 11 at a second end of the sleeve 11 opposite the first end 111 around the tubular body 10 and bearing both against the pump body 2 at an outlet of the bore 20 and against the ring 110 of the sleeve 11. The second seal 42 has a quadrilobe section.

[0040] The construction of the pump, in connection with valve 1, is now described.

[0041] The tubular body 10 containing the elements of the valve 1 is inserted into the bore 20 of the pump body 2. The second seal 42 is inserted onto the tubular body 10 and pushed into abutment 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 is pressed against both the pump body 2 and the ring 110 of the sleeve 11 and the sleeve 11 is welded to the outer corner of connection with the pump body 2.

[0042] 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 face 132 of the support in the direction of the actuation axis A until the support is in abutment against the ring 110 of the sleeve 11. The ring 14 then enters by force into the sleeve 11, which is facilitated by the chamfer 112, and fixes the coil support 13 in the sleeve 11. The first seal 31 is taken between the support seat 33 and the sleeve seat 32 and provides sealing between the two parts 11, 13 with substantially radial contact with the seats 32, 33.

[0043] In a second embodiment, as shown in Figure 3, the valve 1' differs from that of the first embodiment in that the sleeve seat 32' is at the end of the sleeve 11' and the support seat 33' is carried by a shoulder 135 of the coil support 13'. The contact between the first seal 31' and the seats 32', 33' is substantially axial. The assembly order is substantially 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 reached by the coil support 13' in abutment against the ring 110 of the sleeve 11'.

[0044] In a variant, the coil support 13' comprises a drop 136 covering the first end 111' of the sleeve 11', as shown in dotted lines in FIG. 3. No contact is provided between the drop 136 and the sleeve 11'.

[0045] In a third embodiment, as shown in Figure 4, the valve 1" differs from that of the first embodiment in that the sleeve seat 32" is in an inner rebate 34 at the first end 111" of the sleeve 11". The contact between the first seal 31" and the seats 32", 33" is substantially axial. The assembly order is substantially 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 reached by the coil support 13" in abutment against the ring 110 of the sleeve 11". In a variant, the coil support 13" has a drop 136" covering the first end 111" of the sleeve 11", as shown in dotted lines in Figure 4. No contact is provided between the drop 136" and the sleeve 11".

Claims

Claims Fuel pump comprising a pump body (2) and a valve (1), the valve (I) comprising a sleeve (11) of substantially tubular shape, fixed on the pump body (2) and extending along an actuation axis (A) so as to define a coil housing (12), a tubular body (10) of the same axis as the sleeve (II) partially housed in a bore (20) of the pump body (2), an annular electromagnetic coil (12) housed in the sleeve (11) and centered on said actuating axis (A) around the tubular body (10), a coil support (13) carrying the coil (12) and inserted at a first end (111) of the sleeve (11), characterized in that the valve comprises first sealing means (3) comprising a first annular sealing gasket (31) between the coil support (13) and the sleeve (11) bearing on the one hand on a sleeve seat (32) carried by the sleeve (11) at the first end (111) and on the other hand on a support seat (33) carried by the coil support (13).Pump according to claim 1, in which the support seat (33) is carried by a skirt (134) integrated into the coil support (13), of annular shape and covering the first end (111) of the sleeve (11), the sleeve seat (32) being carried on an outside diameter of the sleeve (11). Pump according to claim 1, in which the sleeve seat (32) is at the end of the sleeve (11) and the support seat (33) is carried by a shoulder of the coil support (13). Pump according to claim 3, in which the sleeve seat (32) is in an inner rebate at the first end (111) of the sleeve (11). Pump according to claim 3 or 4, characterized in that it comprises an axial stop to limit the travel of the coil support (13) in the direction of the actuation axis (A). Pump according to claim 3 to 5, in which the coil support (13) comprises a drop (136) covering the first end (111) of the sleeve (11).Pump according to one of the preceding claims, in which the first seal (31) is toric. Pump according to one of the preceding claims, in which the coil support (13) has a bearing face (132) opposite the coil (12) and substantially perpendicular to the actuation axis (A).

9. Pump according to one of the preceding claims, characterized in that it comprises second sealing means (4) comprising a second seal (42) housed in a groove (41) around the tubular body (10) and bearing both against the pump body (2) at an outlet of the bore (20) and against the sleeve (H).

10. Pump according to claim 9, in which the second seal (42) has a quadrilobe section.

11. Pump according to claim 9 to 10, in which the groove is made at a second end of the sleeve (11) opposite the first end (111).

12. Pump according to one of the preceding claims, in which the sleeve (11) is fixed to the pump body (2) by welding (S).

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