WO2012066206A1

WO2012066206A1 - Pressure regulator and fuel supply device comprising such a regulator

Info

Publication number: WO2012066206A1
Application number: PCT/FR2011/052460
Authority: WO
Inventors: Marc Alain Daumas
Original assignee: Peugeot Citroen Automobiles Sa
Priority date: 2010-11-19
Filing date: 2011-10-20
Publication date: 2012-05-24
Also published as: FR2967794A1; EP2640959A1; FR2967794B1

Abstract

The invention relates to a pressure regulator (6) for a liquid, comprising an inlet passage (22) and means for closing off the passage, and characterized in that it comprises a plunger (34), separate from the closing-off means, first retaining means which via the plunger (34) apply to the closing-off means a first retaining force (Fm1), a solenoid (30), and second retaining means which apply to the closing-off means a second retaining force (Fm2), the retaining means acting in parallel on the closing-off means and allowing the liquid to enter when the force of the pressure is greater than the sum of the retaining forces when the solenoid (30) is not energized and preventing the liquid from entering when the pressure force on the closing-off means is lower than the second retaining force (Fm2) when the solenoid (30) is energized. Fuel supply device comprising such a regulator.

Description

Pressure regulator and fuel supply device comprising such a regulator

The present invention claims the priority of French application 059507 filed November 19, 2010 whose content (text, drawings and claims) is here incorporated by reference.

Technical field of the invention

The present invention relates to a liquid pressure regulator. The invention also relates to a high-pressure fuel supply device of an internal combustion engine comprising such a regulator.

Technological background

The fuel supply circuits usually encountered in internal combustion engines of a motor vehicle comprise a high pressure pump, a common injection rail, more generally called "Common Rail" which is supplied with fuel via the pump high pressure and in which the fuel is accumulated under high pressure. This ramp still communicates with the fuel injectors via supply ducts.

Sudden deceleration during a full load phase up to a low speed (typically on the motorway when exiting to a rest area or arriving at a toll) results in a build-up of fuel pressure during deceleration and, because of this excessive fuel pressure, jolts and / or noise during the re-acceleration thus a deterioration of the flexibility of engine recovery. The common rail pressure should be adjusted rapidly between full load and low speed.

Document US5727525 discloses a fuel supply device comprising a high-pressure pump, a common injection rail supplied with fuel via the high-pressure pump and a pressure regulator screwed onto the common rail. The pressure regulator of document US5727525 comprises a pusher also acting as a means of closing a fuel inlet passage in the regulator. This pusher is likely to be moved during the activation of an electromagnet, that is to say a solenoid surrounding a magnetic core. The pusher cooperates with a guide rod to form a hydraulic pressure chamber and is pressed to seal by a pressure spring against a seat so as to be able to blocking the flow of fuel between a fuel passage communicating with the interior of the ramp and a fuel drain passage formed in the body of the pressure regulator. The drain passage allows the return of fuel to a reservoir or a low pressure branch of the fuel supply circuit.

Activation of the electromagnet creates a magnetic force that attracts the pusher and overcomes the holding force of the pressure spring. Thus the pusher can move and allow the flow of fuel between the communicating fuel passage with the interior of the ramp and the drain passage.

Thus, when the electromagnet is not activated, the pusher is pressed on its seat by the force of the spring and the force of the hydraulic pressure chamber, the fuel accumulates in the common rail under a high determined pressure. Beyond a threshold of maximum fuel pressure in the common rail, the fuel pressure force acting on the pusher is greater than the holding force of the pressure spring and the hydraulic pressure force in the chamber, which has the effect of opening the communication between the communicating fuel passage with the interior of the ramp and the fuel drain passage. Moreover, when the electromagnet is activated, below a threshold of minimum pressure, the holding force of the pressure spring is greater than the resultant of the attraction force of the electromagnet and of the hydraulic pressure force in the chamber, which has the effect of closing the communication between the fuel passage communicating with the inside of the ramp and the drain passage.

However, the pressure regulator described in the document US5727525 has several disadvantages: firstly the electromagnetic forces to be generated to attract the pusher in the configuration presented by US5727525 requires the use of a powerful electromagnet and the other hand the realization of the hydraulic balancing chamber requires expensive precision machining to provide guidance.

The invention aims to solve one or more of these disadvantages by proposing a pressure regulator offering similar services, simpler and more robust design. The invention thus relates to a pressure regulator of a liquid comprising an inlet passage of the pressurized liquid in said regulator, means for closing the inlet passage, characterized in that it comprises a separate magnetizable pusher shutter means, first holding means arranged to apply to the closure means, via the pusher, a first holding force to close the inlet passage, the regulator further comprising a solenoid capable of applying to the pusher a magnetic force opposing the first holding force when said solenoid is electrically activated, second holding means arranged to apply to the closure means a second holding force to close the passage input, the first and second holding means acting in parallel on the closure means and being configured in such a way that they are the inlet of the pressurized liquid into the regulator when the force of the liquid pressure in the inlet passage on the sealing means is greater than the sum of the first and second holding forces when the solenoid is not activated and prohibit the entry of pressurized liquid into the regulator when the force of the liquid pressure in the inlet passage on the sealing means is less than the second holding force when the solenoid is activated.

Thus, the fact that the pusher and the shutter means are separate and act in parallel allows a simpler decoupled control and therefore allows a simplified design of the regulator.

In a variant, the second holding means are arranged so as to directly apply to the closure means the second holding force, which further simplifies the design by eliminating the intermediate piece.

In another variant, the second holding means surrounds the pusher, which makes the design even more compact. In another variant, the solenoid has a central recess in which the pusher can move in translation, which further improves the compactness of the assembly, since the pusher is disposed inside the solenoid.

Preferably, the regulator of the invention comprises a socket disposed in the central recess, between the pusher and the solenoid. This socket serves to guide the pusher in translation and to isolate the solenoid from the contact of the liquid. Advantageously, the sleeve comprises a flange bearing on the solenoid, to seal and serving as mounting stopper of the sleeve in the recess.

For the sake of simplicity and robustness, according to one variant, the first holding means comprise a first pressure spring.

Still for the sake of simplicity and robustness, the second holding means comprise a second pressure spring.

In another variant, the sealing means consist of a ball.

The invention also relates to a common rail high pressure fuel supply device characterized in that it comprises a pressure regulator of the invention disposed on the common rail, the common rail having a channel communicating with the passage of regulator inlet to allow the circulation of the fuel present in the common rail to the regulator.

Alternatively, the pressure regulator is disposed in the extension of the common rail. Brief description of the drawings

Other features and advantages will appear on reading the description below of a particular embodiment, not limiting of the invention, with reference to the figures in which: - Figure 1 is a schematic representation of a fuel injection circuit comprising a pressure regulator of the invention.

- Figure 2 is a sectional view of an embodiment of the pressure regulator of the invention. detailed description

Figure 1 shows a common rail fuel supply device for internal combustion engines of a motor vehicle. The common rail fuel supply device generally includes a low pressure pump 1, a high pressure pump 2, an electronic control unit 3, a pressure sensor 4, a common rail 5, a regulator 6 of the fuel pressure . The portion of the fuel supply device located upstream of the high pressure pump 2 constitutes the so-called "low pressure" branch of the fuel supply device while the portion of the fuel supply device located downstream of the pump high pressure 2 constitutes the so-called "high pressure" branch of the fuel supply device.

The low pressure pump 1 has the function of bringing the fuel from a fuel tank (not shown) to the high pressure pump 2. The high pressure pump 2 raises the fuel pressure to a required pressure threshold and feeds the common rail 5.

The common rail 5 still communicates with fuel injectors, not shown, via supply ducts 7. Generally, a common rail has an elongated shape and for the sake of simplicity of design and construction, the pressure regulator 6 is advantageously arranged, as illustrated in FIG. 1, in the extension of the common rail 5. It is in fact furthermore provided that the common rail 5 has a channel 9 allowing the flow of fuel between the common rail 5 and the pressure regulator 6.

The pressure regulator 6 communicates with the so-called "low pressure" branch of fuel supply, that is to say the downstream portion of the high-pressure pump 2, via a fuel return line 8 .

The pressure sensor 4 is connected to the electronic control unit 3. The pressure sensor 4 measures the effective pressure of the fuel in the common rail 5 and provides pressure information to the electronic control unit 3. The regulator 6 pressure device operates in response to a control signal delivered by the electronic control unit 3. When the effective pressure of the fuel in the common rail 5 is greater than a predetermined set pressure, this set pressure being predetermined according to parameters operating the engine such that, by way of example, the speed, the engine load, the electronic control unit 3 provides a signal to the fuel pressure regulator 6 to activate it electrically to reduce the effective pressure fuel at the predetermined set pressure. Figure 2 shows in section the internal structure of the fuel pressure regulator 6 of the invention according to a preferred embodiment. In addition, Figure 2 shows the pressure regulator 6 at its rest state which is still in our embodiment a state commonly referred to as "normally closed".

In this embodiment, the pressure regulator 6 has a main body 1 1 surmounted by an outer casing 10. The main body 1 1 and the casing 10 may be cylindrical, extending along a central axis Z.

The pressure regulator 6 further comprises a solenoid 30, ie a coil of a wound electrical wire. In this embodiment, the solenoid 30 has a cylindrical central recess 31. A cylindrical sleeve 32 is disposed in the central recess 31.

The sleeve 32 is formed of a hollow cylinder 32a, closed at one end by a bottom 32b and having at the other end a flange 32c bearing on the solenoid 30 on one of its faces and resting on the main body 1 1 on the other of its faces. In the sleeve 32 is placed a first pressure spring 33 and a cylindrical pusher 34. The pusher 34 is slidably mounted in the sleeve 32, along the central axis Z, that is to say the pusher can move in translation in the central recess 31, the sleeve being disposed in the recess 31 central between the pusher 34 and the solenoid 30. The pusher 34 must be of a magnetizable material so that, when the solenoid 30 is activated, it applies to the pusher 34 a magnetic force so as to move it in translation along the central axis Z. , the hollow cylinder 32a of the sleeve acts as guide means of the pusher 34. The sleeve 32 also serves to isolate the solenoid of the fuel contact. Advantageously, the sleeve 32 is in a non-magnetizable material but which offers good circulation of the magnetic fields. A socket 32 made of aluminum or non-magnetizable stainless steel is suitable.

The first pressure spring 33 is disposed between the bottom 32b of the sleeve 32 and the pusher 34. The first pressure spring 33 is firstly in contact by one of its ends at the bottom 32b of the sleeve 32 and other part in contact with the other of its ends with the pusher 34. In this embodiment, the pressure regulator 6 has an inlet male connector having an external thread. This connection 20 is intended to screw together the regulator 6 at the common ramp 5 (FIG. 1), the common ramp 5 comprising at its end the complementary female connector, not shown, at the male connector of the pressure regulator 6.

The male inlet 20 has a fuel inlet passage 22 opening on a conical portion forming a seat 23 for a ball 24 shutter. The sealing ball 24 is disposed between the seat 23 and the pusher 34. The regulator 6 further comprises a second pressure spring 25 for pressing the sealing ball 24 against the seat 23. The second pressure spring 25 is disposed between the flange 32c of the sleeve 32 and the ball 24 shutter. The second pressure spring 25 is firstly in contact by one of its ends with the flange 32c and secondly in direct contact with the other of its ends with the ball 24 closing. The ball 24 is non-magnetic so as not to be under the influence of the magnetic field of the solenoid 30 when it is activated. The ball 24 may be non-magnetic metal or hard plastic. An example of a suitable metal may be aluminum or a non-magnetizable stainless steel. As further shown in FIG. 2, in this embodiment, the pusher 34 passes into the second pressure spring 25, ie the second spring 25 surrounds the pusher 34, which forms a compact assembly, substantially of the diameter of the ball. 24. The pressure regulator 6 further comprises at least one internal fuel discharge port 35 connected to a fuel drain channel 36. The emptying channel 36 is arranged in the main body January 1 and opens on the outside of the pressure regulator 6 by an external outlet orifice 37. An outlet connector 38 may be provided to facilitate the connection and assembly of the drain channel 36 to a venting circuit such as the fuel return conduit of the feeder illustrated in FIG.

A ring 39 having a plurality of through passages 40 may be provided and, since they can not all face the emptying channel 36, the ring 39 further has an outer peripheral groove 41 allowing the fuel having passed through any of the passages 40 join channel 36 emptying. Thus the pressurized fuel from the common rail 5 through the inlet passage 22 can, when the flow of fuel is allowed, start through the drain channel 36 to the return line 8 of fuel. The operation of the pressure regulator 6 in the fuel supply device, the channel 9 communicating with the inlet passage 22, is as follows:

When the solenoid 30 is not electrically activated, in other words when the pressure regulator 6 is in the non-controlled state, the first pressure spring 33 acting as the first holding means, applies to the ball 24 shutter by means of the pusher 34, a first holding force Fm1, for closing the input gate 22 and the second pressing spring 25, acting as second holding means, applies to the ball 24 closing a second holding force Fm2 to close the input gate 22. The first and second springs act on the ball 24 shutter in parallel. As shown again in FIG. 2, in such a configuration of springs connected in parallel, the forces in application accumulate, the resultant of the forces of maintenance, Ftot, on the ball is therefore the sum of the first and second holding forces. Fm1 and Fm2 (the force of gravity of the pusher 34 on the ball 24 shutter is here considered negligible). The regulator 6 remains closed, and ensures the increase in pressure of the fuel in the common rail 5 as the fuel pressure in the ramp has not reached a maximum pressure threshold determined P _H.

In the case of a gasoline direct injection engine, this maximum fuel pressure threshold P _H may be between 240 and 280 bar.

The person skilled in the art knows perfectly how to express a pressure in force as a function of the surface of application of the fuel pressure in the inlet passage 22 on the ball 24. Knowing the maximum threshold of pressure and the minimum threshold of pressure required it can therefore determine the corresponding first and second holding forces Fm1 and Fm2 and configure the first and second springs according to their stiffness and elongation to obtain the holding forces Fm1 and Fm2 in question.

Beyond the determined maximum pressure threshold P _H , the fuel pressure force in the inlet passage 22 on the ball 24 is greater than the sum of the first and second holding forces Fm1, Fm2: the first and second springs pressure are no longer sufficient to maintain the ball 24 in contact with its conical seat 23, the ball 24 rises from its seat 23 and allows the fuel entering the regulator 6 through the inlet passage 22 to flow to the drain channel 36 and then to the return line 8 of fuel. When the solenoid 30 is electrically activated, for example by an on-off command delivered by the electronic control unit 3, in other words when the pressure regulator 6 is in the controlled state in order to regulate the fuel pressure at a set pressure, the solenoid 30 applies to the pusher 34 a magnetic force Fmag which opposes the first holding force Fm1. The pusher 34 moves along the central axis Z so as to compress the first compression spring 33. In doing so, the ball 24 no longer in contact with the pusher 34 is released from the mechanical stress imposed by the first spring 33 and the pusher 34, but still remains under the mechanical stress of the second pressure spring 25. The second holding force Fm2 prohibits the entry of pressurized fuel into the regulator as long as the pressure force of the fuel in the passage of input 22 on the ball 24 shutter is less than this second holding force Fm2. Thus, the regulator 6 remains closed, and guarantees a minimum pressure threshold P _L of fuel in the common rail 5 as long as the fuel pressure in the ramp has not reached this minimum pressure threshold P _L. In the case of the application of a gasoline direct injection engine, this minimum pressure threshold P _L may be between 40 to 50 bar.

As long as the set pressure, between the minimum pressure threshold P _L and the maximum pressure threshold P _H , is not reached, the fuel passes through the pressure regulator 6 and joins the low pressure part of the supply device fuel. Once the set pressure is reached and confirmed by the pressure sensor 4, the electronic control unit 3 then releases the electrical control and the pusher 34 returns to bear on the ball 24. In the case where the solenoid 30 remains accidentally activated or the pusher 34 does not come to rest on the ball 24, the second compression spring 25 naturally closes the high pressure circuit by repositioning the ball 24 on its seat 23 when the fuel pressure in the common rail 5 reaches the minimum threshold of pressure P _L , that is, when the pressure force of the fuel on the ball 24 shutter is less than the second holding force, Fm2. This avoids a fuel pressure drop in the common ramp 5 too large which will affect the proper operation of the engine. The parallel assembly of the first and the second spring 33, 25 has the advantage of reducing the power of the solenoid 30 to just necessary to overcome the effort of the first spring 33 alone and therefore its size and the electrical energy consumed when it is activated.

The pressure regulator of the invention is not limited to the embodiment described in this specification. Indeed, the pressure springs acting as holding means can be replaced one or the other for example by spring washers. In this case the spring washer acting as second holding means may surround the pusher 34, the latter passing through a central hole of the washer.

Similarly, the closure means may take a shape other than a ball and be for example in the form of a valve or a closure cone.

Thus, we have a simple pressure regulator because it does not require reliable precision machining since the holding means used are robust and compact and make it possible to control the rapid adjustment of the fuel pressure in a common rail. This pressure regulator is particularly suitable for the regulation of fuel pressure during the transition phase between a full load regime and a low speed. In addition, the pressure regulator of the invention is not sensitive to fluctuations in fuel pressure.

Claims

claims

1. Regulator of pressure (6) of a liquid having an inlet passage (22) of the liquid under pressure in said regulator (6), means for closing the inlet passage, characterized in that it comprises a magnetizable pusher (34) separate from the sealing means, first holding means arranged to apply to the closure means, via the pusher (34), a first holding force (Fm1) for closing the inlet passage (22), the regulator (6) further comprising a solenoid (30) capable of applying to the pusher (34) a magnetic force (Fmag) opposing the first holding force (Fm1) when said solenoid (30) is electrically activated, second holding means arranged to apply on the closure means a second holding force (Fm2) for closing the inlet passage (22), the first and second holding means maintaining acting in parallel on the closure means and configured in such a way that they allow the entry of the pressurized liquid into the regulator (6) when the force of the liquid pressure in the inlet passage (22) on the closure means is greater than the sum of the first and second holding forces when the solenoid (30) is not activated and they prohibit the entry of the pressurized liquid into the regulator (6) when the force of the liquid pressure in the flow passage input to the shutter means is less than the second holding force (Fm2) when the solenoid (30) is activated.

2. Regulator according to claim 1, characterized in that the second holding means are arranged to apply directly to the closure means the second holding force (Fm2).

3. Regulator according to claim 1 or claim 2, characterized in that the second holding means surrounds the pusher (34).

4. Regulator according to any one of the preceding claims, characterized in that the solenoid (30) has a recess (31) in which the central pusher (34) can move in translation.

5. Regulator according to claim 4, characterized in that it comprises a sleeve (32) disposed in the recess (31) central between the pusher (34) and the solenoid (30).

6. Regulator according to claim 5, characterized in that the sleeve (32) comprises a flange (32c) bearing on the solenoid (30).

7. Regulator according to any one of the preceding claims, characterized in that the first holding means comprise a first pressure spring (33).

8. Regulator according to any one of the preceding claims, characterized in that the second holding means comprise a second pressure spring (25).

9. Regulator according to any one of the preceding claims, characterized in that the sealing means consist of a ball (24).

10. Device for supplying high pressure common rail fuel (5) characterized in that it comprises a pressure regulator (6) according to any preceding claim disposed on the common rail (5), the common rail (5) having a channel (9) communicating with the inlet passage (22) of the regulator (6) to allow the circulation of the fuel present in the common rail (5) to the regulator (6).

Fuel supply device according to Claim 10, characterized in that the pressure regulator (6) is arranged in the extension of the common rail.

(5).