EP3899240A1

EP3899240A1 - Fuel supply device

Info

Publication number: EP3899240A1
Application number: EP19813337.3A
Authority: EP
Inventors: Gabriel HAMARD; Jean-Pierre Millon
Original assignee: Renault SA; Nissan Motor Co Ltd
Current assignee: Renault SA; Nissan Motor Co Ltd
Priority date: 2018-12-20
Filing date: 2019-12-05
Publication date: 2021-10-27
Anticipated expiration: 2039-12-05
Also published as: WO2020126528A1; EP3899240B1; FR3090752B1; FR3090752A1; CN113260782B; CN113260782A

Abstract

Fuel supply device (10), characterised in that it comprises: · a pump (11) suitable for pressurising a fuel, · a first housing (21) at least partially surrounding the pump (11), · a buffer volume (23) defined between the first housing (21) and the pump (11), · a fuel inlet (33) to the buffer volume (23) intended to be connected upstream to a fuel tank (5), · a first fuel outlet (31) from the buffer volume (23) to the pump (11), · a second fuel outlet (32) from the buffer volume (23) intended to be connected downstream to a fuel tank (5).

Description

Title of the invention: Fuel supply device.

The invention relates to a fuel supply device, in particular of

diesel fuel, the fuel supply device comprising a pump, in particular a high pressure pump. The invention also relates to a powertrain comprising such a fuel supply device. The invention also relates to a motor vehicle comprising such a fuel supply device or such a powertrain.

Combustion engines, in particular diesel engines, generally include

actually a pump, called a "high pressure" pump connected to a fuel injection system. The pump is connected upstream to a fuel tank and is able to put the fuel at high pressure in order to inject it into the combustion chambers of the engine. For this purpose, the pressurized fuel can be led from the pump to a common injection rail, then from this rail to injectors opening into the different combustion chambers.

We know the use of a filtration device, also known as

anglicism "damper", interposed between the fuel tank and the pump. This filtration device includes a buffer tank, an inlet connected to the fuel tank, a first outlet connected to the pump and a second outlet, called a "return" outlet, also connected to the tank. This filtration device makes it possible in particular to regulate the fuel pressure upstream of the pump and thus to lower the sizing requirements of the hydraulic connectors of the pump.

The installation of a filtration device in a powertrain requires a large available volume in the engine compartment, as much for the buffer tank itself as for the connecting pipes between the filtration device and the tank and between the filtration device and the pump. In addition, the paths of these connecting pipes must include little or no bend or curvature in order to avoid pressure losses within the pipes. Finally, the materials chosen for the connection pipes must take account of the interface and sealing constraints with the buffer tank. Thus, when the buffer tank is made of plastic, the connection pipes cannot be metallic. Finally, the filtration device must also have a low sensitivity to thermal radiation and be as light as possible.

The object of the invention is to provide a fuel supply device

overcoming the above drawbacks and improving the devices known from the prior art. In particular, the invention makes it possible to produce a fuel supply device which is compact, easy to install, robust and light. The invention relates to a fuel supply device comprising:

- a pump capable of putting fuel under pressure,

- a first casing at least partially enveloping the pump,

- a buffer volume defined between the first casing and the pump,

- a fuel inlet to the buffer volume and intended to be connected upstream to a fuel tank,

- a first fuel outlet from the buffer volume to the pump,

- a second fuel outlet from the buffer volume and intended to be connected downstream to a fuel tank.

The pump may include a second housing at least partially enveloping the pump, the first housing enveloping the second housing, the buffer volume being defined between the first housing and the second housing.

The first housing and the second housing can form a one-piece assembly, in particular an assembly obtained by molding.

The first housing and / or the second housing can be made of plastic.

The first housing and the second housing can form a one-piece metal assembly obtained by deformation of the sheet and / or by welding.

The second fuel outlet may include a valve, the valve being able to open if the fuel pressure in the buffer volume exceeds a pressure threshold.

The first fuel outlet may include a first hydraulic connection. The second fuel outlet may include a second hydraulic connection. The fuel inlet may include a third hydraulic connection.

The first hydraulic connection can extend from the second casing to

inside the buffer volume. The second hydraulic connection can extend from the first casing towards the outside of the buffer volume. The third hydraulic connection can extend from the first casing towards the outside of the buffer volume.

The first hydraulic connection and the second hydraulic connection can

extend in different directions, including directions perpendicular to each other. The first hydraulic connection and the third hydraulic connection can extend in different directions, in particular directions perpendicular to each other.

The fuel supply device can include:

- a first seal at the interface between the first hy connector

and the second casing, and / or

- a second seal at the interface between the second hydraulic connection and the first casing, and / or

- a third seal at the interface between the third hy- and the first casing.

The second housing can match the shape of the pump, and / or the first housing can have a substantially parallelepiped shape.

The pump may be able to put diesel under a pressure of at least 1000 bars, or even at least 2000 bars.

The pump may include a cam follower piston, the pump being able to be driven in operation by the rotation of a cam in contact with the cam follower piston.

The first casing and / or the second casing may comprise a fixing flange intended to fix the fuel supply device to an engine block.

The invention also relates to a powertrain comprising a

fuel supply device as defined above and a fuel injection system, the fuel supply device being connected downstream to the fuel injection system.

The invention also relates to a motor vehicle comprising a fuel tank, a fuel supply device as defined above and / or a powertrain as defined above, the fuel supply device being connected to the fuel tank through the fuel inlet and through the second fuel outlet.

These objects, characteristics and advantages of the present invention will be explained in detail in the following description of a particular embodiment made without limitation in relation to the attached figures, among which:

[Fig.l]

Figure 1 is an isometric view of a pump and a filtration device according to the state of the art.

[Fig.2]

FIG. 2 is a partial isometric view of the pump and of a filtration device according to the state of the art.

[Fig.3]

Figure 3 is an isometric view of the pump fitted with a protective casing.

[Fig.4]

FIG. 4 is a schematic view of a motor vehicle according to an embodiment of the invention.

[Fig.5]

FIG. 5 is an isometric view of a pump of a fuel supply device according to an embodiment of the invention.

[Fig.6]

Figure 6 is a sectional view of a fuel supply device according to a embodiment of the invention.

In this document, the terms "upstream" and "downstream" refer to the meaning

for the flow of a liquid, in particular a fuel, the liquid flowing from upstream to downstream.

To fully understand the invention we will first describe a

powertrain G according to the state of the art with reference to Figures 1, 2 and 3. The powertrain G comprises a 2 ’engine block on which various equipment is attached. In particular, the powertrain G comprises a 3 ’pump, called a“ high pressure pump ”and a 4’ filtration device. The pump 3 'is capable of putting fuel, in particular diesel, under pressure with a view to its injection into combustion chambers of the powertrain G. The pump 3' comprises a low pressure inlet 5 'and a high pressure outlet 6' . The filtration device 4 ’, sometimes called anglically“ damper ”, in particular makes it possible to regulate the fuel pressure upstream of the pump 3’. To this end, the filtration device comprises a buffer tank 7 ', an inlet 8' connected to a fuel tank, a first outlet 9 'connected to the pump 3' and a second outlet 10 ', called "return", also connected to the fuel tank. The powertrain 1 'therefore comprises a first pipe 1 G connecting the first outlet 9' to the pump 3 ', a second pipe 12' connecting the second outlet 10 'to the fuel tank, a third pipe 13' connecting the inlet 8 'to the fuel tank, and a fourth line 14' connecting the pump 3 'to an injection device such as an injection rail. These pipes have bends or bends in order to orient the ends of the pipes parallel to the inlets and outlets of the pump 3 ’and of the filtration device 4’. In particular, the first outlet 9 'of the filtration device 4' and the low pressure inlet 5 'of the pump 3' are substantially oriented in perpendicular directions. The first pipe 1G includes two 90 ° elbows to connect the first outlet 9 ’to the low pressure inlet 5’.

Furthermore, the pump 3 ’is protected by a protective housing 15’. The protective casing 15 ′ also envelops a downstream part of the first pipe 1 G. The first pipe must therefore run as far as possible along the body of the pump 3 ’in order to limit the size of the protective casing 15’.

When the engine is running, the fuel present in the fuel tank passes successively through the third line 12 ', the buffer tank 7' and the first line 10 'before reaching the pump 3' or it is put under pressure. The fuel pressurized by the pump is then directed to the injection system via the fourth line 13 '. In the event of excessively high fuel pressure in the buffer tank, part of the diesel present in the buffer tank is redirected to the fuel tank via the second 1 G line. lines with many bends, fuel pressure losses occur inside the lines 1 G, 12 ', 13', 14 '.

We will now describe a motor vehicle 100 equipped with a powertrain 1 and a fuel supply device 10 according to an embodiment of the invention with reference to Figures 4, 5 and 6.

Figure 4 schematically illustrates the vehicle 100 according to an embodiment of the invention. The vehicle 100 can be of any kind. In particular, it may for example be a private vehicle, a utility vehicle, a truck or a bus. The powertrain 1 comprises a combustion engine 2, a fuel injection system 3 and the fuel supply device 10. Preferably the combustion engine is a diesel engine, that is to say it is able to function thanks to the combustion of diesel fuel. The combustion engine 2 comprises an engine block in which combustion chambers are hollowed out. It further comprises rotating shafts 4, in particular a crankshaft, camshafts, or even balancing shafts. The fuel injection system 3 may include a fuel distribution rail to which are connected injectors opening into the different combustion chambers. The motor vehicle 100 also comprises a fuel tank 5 connected to the powertrain 1.

The fuel supply device 10 is connected downstream to the fuel injection system 3 by a first pipe 6. The fuel supply device 10 is also connected to the tank by a second pipe 7 and by a third pipe 8. The first pipe 6 is a so-called “high pressure” pipe insofar as it is capable of containing fuel under a pressure which can reach 1000 bars, or even 2000 bars, or even 3000 bars. The second line 7 and the third line 8 are so-called “low pressure” lines insofar as they are capable of containing fuel under a pressure of the order of only a few bars.

The fuel supply device 10 comprises a pump 11 capable of pressurizing the fuel, a first casing 21 at least partially enveloping the pump 11, and a buffer volume 23 defined between the first casing 21 and the pump 11 .

The pump 11 is particularly visible in Figure 5. Note, in Figure 5 the first housing 21 is not shown to be able to observe the pump 11. The pump 11 is fixed to the engine block and is suitable for pressurize fuel. According to a preferred embodiment of the invention, the fuel is diesel and the pressure of the diesel at the outlet of the pump 11 can reach 1000 bars, or even 2000 bars, or even 3000 bars. The pump 11 can thus be called “high pressure pump”. The pump 11 may include one or more pistons driven in movement by the combustion engine. For example, the pump may include a pump body 12 and a single cam follower piston 13 movable in translation inside the pump body. The cam follower piston 13 is fitted at one end with a cam follower 14, in particular a cam follower bearing. The cam follower 14 bears against a cam 9 fixed to a rotating shaft 4 of the combustion engine. The positioning of the pump in the powertrain is therefore at least partly imposed by the position of the rotating shafts. The pump 11 is supported on the engine block via a face 15 of the pump 11. The rotation of the rotating shaft 4 causes the displacement of the cam follower piston 13 and the pressurization of the fuel inside the pump 11. The pump is therefore able to be driven in operation by the rotation of the cam 9 in contact with the cam follower piston 13. As a variant, the rotating shaft 4 supporting the cam 9 could be a clean shaft of the pump 11 and not a rotating shaft of the combustion engine. The rotation of the rotating shaft specific to the pump 11 could then be obtained by connecting the pump to the crankshaft, to a camshaft or to a balancing shaft by means of gears, a chain or a belt.

The pump 11 includes a second housing 22 clearly visible in Figure 5. The

second housing 22 follows the shape of the pump 11 and forms a sealed envelope around the body of the pump 12. The volume between the pump body 12 and the second housing 22 may be small or even zero. Advantageously, the second casing 22 protects the pump body while limiting the size of the pump 11.

The first casing 21, visible in particular in FIG. 6, is a housing or in other words a casing at least partially enveloping the pump 11. The first casing 21 therefore also envelops the second casing 22 of the pump 11. In other words, the first casing 21 covers or at least partially covers the pump 11. Advantageously the first casing 21 can cover at least one face of the pump 1, preferably at least two faces of the pump 11. According to the embodiment presented, the first casing 21 covers all the faces of the pump 11 with the exception of the face 15 of the pump 11 bearing on the engine block. When the fuel supply device 10 is fixed to the engine block, the pump 11 is therefore not visible and it is completely protected by the first casing 21.

The first housing 21 is fixed to the pump 11. It may have a shape substantially pa parallelepipedal or alternatively any other shape imposed by the environment of the fuel supply device. The buffer volume 23 is defined between the first casing 21 and the second casing 22. It can have any shape. This buffer volume 23 is a volume capable of containing fuel upstream of the pump 11. According to an alternative embodiment, the pump 11 may not include the second casing 22 and the buffer volume 23 would then be defined between the first casing and the body of the pump 12 directly.

Advantageously, the first casing 21 and / or the second casing 22 are made of plastic, in particular in a plastic suitable for contact with a fuel and having a low sensitivity to thermal radiation. The first casing 21 and / or the second casing 22 may both be one-piece parts obtained by plastic injection. Alternatively, the first housing 21 and the second housing 22 could form a one-piece assembly obtained by molding, in particular by rotational molding. The use of plastic makes it possible to design the first housing and the second housing according to a freedom of form. The shape of the first housing 21 can therefore adapt to the environment close to the fuel supply device 10 and the shape of the second housing 22 can therefore adapt to the shape of the pump body 21. According to another variant , the first casing 21 and the second casing 22 could form a one-piece metal assembly obtained by deformation of the sheet, in particular by stamping and / or by welding. Different sheet metal elements could be welded together so as to form a sealed buffer volume.

The first housing 21 and / or the second housing 22 may include a fixing flange intended to fix the fuel supply device 10 to the engine block. As shown in Figure 5, the second housing 22 includes at least one flange 24 provided with a circular opening for attachment to the engine block. Advantageously, the first housing and the second housing each comprise a fixing flange provided with fixing openings. The openings of the first flange then coincide with the openings of the second flange so that the fixing of the fuel supply device to the engine block also makes it possible to secure the first casing 21 to the second casing 22.

The fuel supply device 10 further comprises a first fuel outlet 31 from the buffer volume 23 to the pump 11, a second fuel outlet 32 from the buffer volume 23 to the fuel tank 5, and a fuel inlet 33 from the fuel tank 5 to the buffer volume 23. The fuel therefore enters the buffer volume 23 through the inlet 33 and out of it through the first outlet 31 or through the second outlet 32. Outside the three openings formed by the inlet 33 and the two outlets 31, 32, the buffer volume 23 is sealed. In particular, the first casing is linked to the second casing so as to form a sealed interface. The fuel cannot therefore enter or leave the buffer volume 23 other than through the inlet 33 or through the outlets 31, 32. The second outlet 32 is therefore connected to the fuel tank 5 by the second pipe 7. The inlet 33 is therefore connected to the fuel tank 5 by the third pipe 8. The first outlet allows the fuel contained in the buffer volume to pass directly to the pump 11 without passing through any pipe. The first outlet 31 comprises a first hydraulic connection 41. The second outlet 32 comprises a second hydraulic connection 42. The inlet 33 comprises a third hydraulic connection 43. Each of these three hydraulic connections 41, 42, 43 can be presented in the form of a generally cylindrical tube and or or in the form of a snap-on fitting. As a variant, the first hydraulic connection 41 could be replaced by a simple opening allowing the pump 11 to communicate with the buffer volume 23. However, the invention makes it possible to use a pump 11 already provided with a hydraulic connection without modifying it . The second hydraulic connection 42 and the third hydraulic connection 43 can be provided with means for fixing respectively to the second pipe 7 and to the third pipe 8. These fixing means can for example be a thread or circumferential grooves. Hydraulic fittings can be made of any material suitable for driving diesel. Advantageously, they are chosen from a material compatible with the material forming the pipes to which they are connected.

The first hydraulic connection 41 extends from the second casing 22 towards

inside the buffer volume 23. In particular, the first hydraulic connection can extend perpendicular to the face 15 of the pump 11 along which the supply device 10 is fixed to the engine block. The direction in which the first hydraulic connection 41 extends can also be parallel to the direction in which the cam follower piston 13 is movable. The second hydraulic connection 42 and the third hydraulic connection 43 both extend from the first housing 21 towards the outside of the buffer volume 23. In other words, the two hydraulic connections 42, 43 project from the first housing 21 towards the exterior of the fuel supply device 10. The first hydraulic connection 41 and the second hydraulic connection 42 extend in directions perpendicular to one another. Likewise, the first hydraulic connection 41 and the third hydraulic connection 43 extend in directions perpendicular to one another. In particular, the two hydraulic connections extend parallel to face 15 and in opposite directions. Alternatively, the hydraulic connections could be oriented differently to facilitate the installation of lines 7 and 8 while limiting the pressure losses in these lines.

The fuel supply device 10 further comprises a first seal 51 at the interface between the first hydraulic connection 41 and the second casing 22, a second seal 52 at the interface between the second hydraulic connection 42 and the first housing 21, and a third seal 53 at the interface between the third hydraulic connection 43 and the first housing 21.

The second outlet 32 includes a valve 34, called "pressure relief valve". The valve 34 is capable of opening if the fuel pressure in the buffer volume 23 exceeds one given pressure threshold. Advantageously, the valve 34 can be a completely mechanical and autonomous device. It can for example include a spring or a membrane. As a variant, the fuel supply device could not include a valve, the mere presence of the buffer volume sufficient to regulate the fuel pressure upstream of the pump 11.

For the manufacture of the fuel supply device 10, it is possible to take a pump 11 as supplied by a pump manufacturer and add the first casing 21 equipped with the second outlet 32 and the inlet 33 to this pump. When fixing the first housing 21 to the pump, it can be ensured that the interface between the first housing 21 and the second housing 22 is sealed. For mounting the fuel supply device 10 within the powertrain 1, the fuel supply device 10 can be fixed by means of the fixing flange (s) 24. The supply device is connected in fuel 10 to the fuel injection system 3 with the first line 6 and the fuel supply device 10 is connected to the fuel tank 5 with the second line 7 and with the third line 8. Compared to the powertrain G according to l 'state of the art, this saves the mounting and use of the connection line 1 G. Assembly is therefore facilitated and pressure losses occurring inside the 1G connection pipe are avoided. It also avoids fuel leakage problems that can occur at the interface between the 1 G connection line and the 4 ’filtration device or at the interface between the 1 G connection line and the 3’ pump. We also limit the number of hydraulic connections which are all sensitive points in the event of a vehicle accident 100.

When the powertrain 1 is running, the fuel flows from the

fuel tank 5 to the fuel supply device 10 via the third line 8. It enters the buffer volume 23 via the inlet 33. The fuel passes from the buffer volume 23 to the pump 11 via the first outlet 31. Within the buffer volume 23, the fuel flow is directed from a direction parallel to the inlet 33 to a direction parallel to the first outlet 31. This thus manages to modify the orientation of the flow of the fuel without using an elbow in a line. The fuel is pressurized by the pump 11 and is then directed to the fuel injection system 3 via the first line 6. It is then injected into the combustion chambers. If the pressure within the buffer volume 23 reaches a predefined threshold, for example due to leaks from the pump 11 towards the low pressure circuit, the valve 34 opens and lets the fuel return to the tank. This ensures a stable pressure upstream of the pump 11. The buffer volume 23 provides fine regulation of the pressure upstream of the pump but also makes it possible to limit fuel overpressures. Such a buffer volume 23 allows also to reduce the acoustic impact linked to pressure variations. The buffer volume 23, directly attached to the pump 11, contributes to acoustically isolating the pump 11.

Finally, the first casing 21 combines the protection functions of the pump 11, forms a wall of the buffer volume 23 and allows the device to be fixed

fuel supply to the engine block if it includes a mounting flange. In other words, the filtration device is directly integrated under the first casing 21 protecting the pump 11. This thus achieves a compact powertrain, easy to install, robust and light.

Claims

[Claim 1] Fuel supply device (10), characterized in that it comprises:

• a pump (11) capable of putting fuel under pressure,

A first casing (21) at least partially enveloping the pump (11),

• a buffer volume (23) defined between the first casing (21) and the pump (11),

A fuel inlet (33) to the buffer volume (23) and intended to be connected upstream to a fuel tank (5),

A first fuel outlet (31) from the buffer volume (23) to the pump (11),

• a second fuel outlet (32) from the volume

buffer (23) and intended to be connected downstream to a fuel tank (5).

[Claim 2] Fuel supply device (10) according to claim

previous, characterized in that the pump (11) comprises a second housing (22) at least partially enveloping the pump (11), the first housing (21) enveloping the second housing (22), the buffer volume (23) being defined between the first housing (21) and the second housing (22).

[Claim 3] Fuel supply device (10) according to claim

previous, characterized in that the first casing (21) and the second casing (22) form a one-piece assembly, in particular an assembly obtained by molding.

[Claim 4] Fuel supply device (10) according to one of the reven

dications previous, characterized in that the first housing (21) and / or the second housing (22) are made of plastic.

[Claim 5] Fuel supply device (10) according to claim 2, ca characterized in that the first casing (21) and the second casing (22) form a one-piece, metallic assembly, obtained by deformation of sheet metal and / or by welding.

[Claim 6] Fuel supply device (10) according to one of the reven

dications preceding, characterized in that the second fuel outlet (32) comprises a valve (34), the valve (34) being able to open if the fuel pressure in the buffer volume (23) exceeds a pressure threshold.

[Claim 7] Fuel supply device (10) according to one of the reven

previous indications, characterized in that:

The first fuel outlet (31) comprises a first hydraulic connection (41), and / or

The second fuel outlet (32) comprises a second hydraulic connection (42), and / or

• the fuel inlet (33) includes a third hydraulic connection (43).

[Claim 8] Fuel supply device (10) according to claim

previous, characterized in that:

• the first hydraulic connection (41) extends from the

second casing (22) towards the inside of the buffer volume (23), and / or

• the second hydraulic connection (42) extends from the

first casing (21) towards the outside of the buffer volume (23), and / or

• the third hydraulic connection extends from the first casing (21) to the outside of the buffer volume (23).

[Claim 9] Fuel supply device (10) according to one of the reven

dications 7 or 8, characterized in that:

• the first hydraulic connection (41) and the second hydraulic connection (42) extend in different directions, in particular directions perpendicular to each other, and / or

• the first hydraulic connection (41) and the third hydraulic connection (43) extend in different directions, in particular directions perpendicular to each other.

[Claim 10] Fuel supply device (10) according to one of the reven

dications 7 to 9, characterized in that it includes:

a first seal (51) at the interface between the first hydraulic connection (41) and the second housing (22), and / or a second seal (52) at the interface between the second hydraulic connection (42) and the first housing (21), and / or

a third seal (53) at the interface between the third hydraulic connection (43) and the first casing (21).

[Claim 11] Fuel supply device (10) according to one of the reven

dications previous, characterized in that the second housing (22) follows the shape of the pump (11), and / or in that the first housing (21) has a substantially parallelepiped shape.

[Claim 12] Fuel supply device (10) according to one of the reven

dications preceding, characterized in that the pump (11) is able to put diesel under a pressure of at least 1000 bars, or even at least 2000 bars.

[Claim 13] Fuel supply device (10) according to one of the reven

above, characterized in that the pump (11) comprises a cam follower piston (13), the pump (11) being able to be driven in operation by the rotation of a cam (9) in contact with the follower piston cam (13).

[Claim 14] Fuel supply device (10) according to one of the reven

dications preceding, characterized in that the first housing (21) and / or the second housing (22) comprises a fixing flange (24) intended to fix the fuel supply device (10) to an engine block.

[Claim 15] Powertrain (1), characterized in that it comprises a

fuel supply device (10) according to one of the preceding claims and a fuel injection system (3), the fuel supply device (10) being connected downstream to the fuel injection system (3).

[Claim 16] Motor vehicle (100), characterized in that it comprises a

fuel tank (5), a fuel supply device (10) according to one of claims 1 to 14, and / or a powertrain (1) according to the preceding claim, the fuel supply device (10 ) being connected to the fuel tank (5) by the fuel inlet (33) and by the second fuel outlet (32).