Fuel accumulator having a filter

Abstract

 An apparatus for supplying fuel to a plurality of injectors of a combustion engine or the like, comprises rail means (12) having an inlet (16a, 18a) for the supply of fuel into the rail means and at least one outlet (16b - 16e, 18b-18e) for the delivery of fuel to the injectors. The rail means (12), in the form of a common rail, includes filter means (22; 42) for collecting and/or filtering particles carried in the fuel. The filter means (22; 42) is non-removably disposed within the rail means (12) and arranged so that an opening (26a; 44) thereto aligns with the inlet (16a, 18a) to the rail means (12).

Description

[0001] The present invention is concerned with improvements in or relating to fuel systems and particularly, but not exclusively, to an apparatus for improving the performance of injectors and other components associated with the supply of fuel to an engine such as a vehicle internal combustion engine. The invention finds particular application in so-called common rail fuel injection systems.

[0002] It is known to supply fuel to engines such as vehicle internal combustion engines by means of a so-called "common-rail" injection system. In such systems, one or more injectors are arranged to inject predetermined quantities of fuel into a respective cylinder of the combustion engine. Each injector is supplied with fuel via a single volume known as a common rail. A fuel pump, which is frequently engine-driven, supplies a high pressure stream of fuel to the common rail from where it is distributed, under pressure, to the injectors for injection into the engine.

[0003] One form of common rail, for example described in published US patent no. 6,260,538, comprises a generally spherical or cylindrical container defining a fuel volume into which a plurality of ports open. One of the ports constitutes an inlet port for the supply of high pressure fuel into the container from a high pressure fuel pump. The remaining ports are outlet or delivery ports for the delivery of fuel from the common rail to the injectors of the engine. In some forms of common rail, the inlet port is disposed diametrically opposite one of the outlet ports, whilst in other devices the ports are oriented so that none are diametrically opposed.

[0004] The applicant has discovered that, in common rails having an inlet port which is directed towards, or diametrically opposed to, one of the outlet ports, the injector connected to that outlet port suffers a proportionately higher incidence of failure than other injectors. It was found that this failure was primarily due to particles contained in the fuel itself. Particles having sufficient inertia are carried to the outlet port diametrically opposite the inlet port by the flow of fuel into the common rail. It was identified that such particles tend to follow a generally straight line from the inlet port to the outlet port and are thus fed to the injector, placing an undue load on the injector and potentially leading to malfunction thereof.

[0005] Furthermore, even where the inlet port is not aligned with an outlet port, injector failure can occur due to random particles in the fuel being fed to the injectors.

[0006] If it were possible to reduce the number of particles in the fuel being delivered to the injectors, the incidence of injector failure due to particle contamination should reduce. It is an aim of the present invention to provide an apparatus to address this previously unidentified technical problem and, hence, to improve the performance of such common-rail fuel injection systems.

[0007] According to one aspect of the present invention, therefore, there is provided an apparatus for supplying fuel to a plurality of injectors of a combustion engine or the like, the apparatus comprising rail means having an inlet for the supply of fuel into the rail means and at least one outlet for the delivery of fuel to the injectors, characterised in that the rail means includes a filter means for filtering and/or collecting particles carried in the fuel, the filter means being non-removably disposed within the rail means and arranged so that an opening thereof aligns with the inlet to the rail means.

[0008] The rail means may have a plurality of inlets, with the filter means being provided with a corresponding number of openings, each being in alignment with a respective one of the inlets.

[0009] The apparatus of the invention utilises the characteristic that particles entering the common rail have a predominant flow path and, thus, arranges a filter means appropriately to filter out and/or collect particles from the fuel within the rail means. This prevents particles being conveyed through any of the outlets and, thus, prevents such particles reaching and damaging the injectors. This advantageously reduces the burden on the filter components of the injectors themselves (e.g. injector edge filters).

[0010] As the filter means is non-removably mounted within the rail volume, there is no requirement to change the filter means during rail service life, making the apparatus particularly convenient.

[0011] In a preferred embodiment of the invention, the rail means includes a wall section defining a fuel volume, the filter means being disposed within the fuel volume.

[0012] In one embodiment of the invention, the filter means includes a tube mounted within the fuel volume, the tube having a tube wall provided with an opening aligned with and/or directed towards the inlet port.

[0013] The tube may be provided with at least one baffle to define a partition between an upper volume of the tube and a quiescent chamber of the tube. The baffle may be provided with a plurality of slots to define a baffle grid.

[0014] In another preferred embodiment, first and second baffles may be provided to define first and second distinct chambers within the tube, the first chamber defining a quiescent chamber for collecting particles therein. Preferably, the second chamber includes a vent or orifice to permit filtered fuel to exit the tube and to return to the main flow path to the at least one outlet. Conveniently, the vent takes the form of a cruciform section, or the like.

[0015] In another embodiment, the filter means may comprise a wall defining a channel having an opening at one end thereof for the passage of fuel therein. The wall may be convoluted such that the channel comprises three channel regions arranged substantially in a U-shape or a C-shape. In this embodiment, the wall of the filter means may be integrally formed with the wall section, or may be a separate structure fixedly mounted thereto.

[0016] A first one of the channel regions may have the opening disposed at one end thereof and may be tapered or funnelled towards the other end thereof. The opening in the first channel region may be adjacent to and/or directed towards the inlet port.

[0017] A second one of the channel regions may be oriented generally perpendicularly to the first channel region. The second one of the channel regions may include a selective barrier means disposed in the wall defining the channel. The selective barrier means may comprise a cribriform section, or the like.

[0018] Advantageously, the selective barrier means may be arranged to permit fuel to pass through, from the channel into the fuel volume, but to prevent the passage of particles above a predetermined size. For example, the minimum particle size to be filtered may be 10 p,m in some systems, or as small as 5 µm in others. Particles that arise as burrs or debris from the high pressure common rail pump, or due to pressure pulsation and engine/chassis vibration, typically have sizes in excess of 5 or 10 µm. It is particles of this nature, in particular, which the invention is intended to filter out of the flow to the injectors.

[0019] A third one of the channel regions may be oriented generally perpendicularly to the second channel region and substantially parallel to the first channel region. The third channel region may be closed at one end to define a quiescent chamber within the channel. The quiescent chamber may be arranged to collect and retain the particles of predetermined size therein.

[0020] The selective barrier means is oriented and configured so as to dissipate energy/momentum from particles above the predetermined size, returning them to the flow into the quiescent chamber, and allowing 'filtered' fuel to pass therethrough into the remainder of the fuel volume.

[0021] The filter means may include restrictor means disposed within the channel for reducing or damping pressure waves within the fuel. The restrictor means may consist of a narrowed region of the channel.

[0022] According to a second aspect of the invention, there is provided an apparatus for supplying fuel to a plurality of injectors of a combustion engine or the like, the apparatus comprising a rail volume including a region of part-spherical form, the rail volume having at least one inlet for the supply of fuel into the rail volume and at least one outlet for the delivery of fuel at an injectable pressure level to the injectors, wherein the rail volume includes a filter means for filtering and/or collecting particles carried in the fuel, the filter means including a tubular member having a tube wall provided with an opening which is aligned with the inlet port.

[0023] Preferably, the tubular filter means is non-removably mounted within the rail volume so that there is no requirement to change the filter means during rail service life.

[0024] Preferred and/or optional features of the first aspect of the invention, may be incorporated within the second aspect of the invention also.

[0025] For example, the tube may be provided with at least one baffle to define a partition between an upper volume of the tube and a quiescent chamber of the tube. The baffle may be provided with a plurality of slots to define a baffle grid.

[0026] Alternatively, first and second baffles may be provided to define first and second distinct chambers within the tube, the first chamber defining a quiescent chamber for collecting particles therein. The second chamber may include a vent or orifice to permit filtered fuel to exit the tube and to return to the main flow path to the at least one outlet. Conveniently, the vent takes the form of a cruciform section.

[0027] The present invention will now be described, by way of example only, with reference to the accompanying drawings in which:

Figure 1 illustrates a known form of apparatus for supplying fuel to the injectors of a combustion engine or the like;

Figure 2 is a cross-section through the apparatus of Figure 1;

Figure 3 is a transverse section through an apparatus embodying a first form of the invention;

Figure 4 is a longitudinal section through an apparatus embodying a second form of the invention;

Figure 5 is a transverse section through the apparatus of Figure 4;

Figure 6 is a longitudinal section through an apparatus embodying a third form of the invention;

Figure 7 is a transverse section through the apparatus of Figure 6;

Figure 8 is a longitudinal section through an apparatus embodying a fourth form of the invention;

Figure 9 is a transverse section through the apparatus of Figure 8;

Figure 10 is a longitudinal section through an apparatus embodying a fifth form of the invention;

Figure 11 is a transverse section through the apparatus of Figure 10;

Figure 12 is a longitudinal section through an apparatus embodying a sixth form of the invention; and

Figure 13 is a transverse section through the apparatus of Figure 12.

[0028] Referring firstly to Figures 1 and 2, a known form of apparatus for supplying fuel to the injectors of a combustion engine or the like is shown generally at 10. The apparatus 10 comprises rail means in the form of a generally cylindrical hub 12 known conventionally as a "common rail". The rail 12 has a wall section 14, formed from a rigid material such as steel, which defines an enclosed fuel volume 15. In the illustrated embodiment, the wall section 14 is formed as a single piece but, in practice, it may be formed from two or more pieces mated or bonded together. At its upper end, the rail volume 15 is of part-spherical form with the main body of the volume 15 being of substantially cylindrical form. Due to the presence of the upper, part-spherical volume a rail of the type shown in Figures 1 and 2 is often referred to in the art as a 'spherical rail'.

[0029] The rail 12 is provided with a plurality of pipes or conduits 16a - 16e which open into the fuel volume 15 via respective apertures 18a - 18e disposed in the wall section 14. In the illustrated embodiment, the rail 12 includes five apertures 18a - 18e, each spaced about the surface of the wall section 14. Each pipe 16a - 16e is seated in its respective aperture 18a - 18e, sealingly bonded to, or formed integrally with, the wall section 14, and extends radially outwardly from the rail 12.

[0030] A first one of the pipes 16a defines an inlet or rail entry passage to the rail 12. One end of the pipe 16a is connected to, and in fluid communication with, a high pressure fuel pump (not shown) for the supply of high pressure fuel, at an injectable pressure level, into the fuel volume 15. The remaining pipes 16b - 16e represent outlets or delivery passages from the rail 12, being connected to, and in fluid communication with, an inlet of a respective injector of the engine (not shown) for the supply of fuel from the fuel volume 15 to the injectors.

[0031] In the illustrated embodiment, the rail 12 has four delivery passages 16b - 16e, indicating that the engine to which the apparatus 10 is connected is a four-cylinder engine having four injectors. It will be understood, however, that where the apparatus 10 is used with an engine having a different number of engine cylinders, be it more or less than four cylinders, then a corresponding different number of delivery ports would be provided in the wall section 14 for communication with a corresponding number if delivery passages.

[0032] In use, fuel at high pressure is supplied from the fuel pump to the fuel volume 15 via the inlet passage 16a and the inlet port 18a defined thereby. From the fuel volume 15, the fuel is delivered, still at a high pressure, to the injectors of the engine via the delivery passages 16b - 16e and outlet ports 18b - 18e defined thereby. Thus, there is a stream of fuel entering the fuel volume 15 through the inlet passage 16a, and flowing out of the fuel volume through the delivery passages 16b - 16e.

[0033] The apparatus of Figure 1 is well known and commonly used in fuel supply systems. During routine testing activity of this type of apparatus, the present applicant made the surprising discovery that failure of the injectors of the engine to which the apparatus is connected is not always a random occurrence, as previously assumed. Instead, the applicant found that injector failure is more common in injectors connected to the rail 12 via a delivery port, which is substantially diametrically opposed to the inlet port 18a of the rail 12.

[0034] The applicants deduced that this failure may be due to the presence of impurities or particles within the fuel. It was found that particles having sufficient mass, and hence inertia, enter the fuel volume 15 from the inlet port 18a and are carried to the delivery port diametrically opposite (delivery port 18d in Figure 1) in a generally straight line, in a regular stream as illustrated. These particles are then carried to the corresponding injector causing it to fail.

[0035] The applicants subsequently determined that it may be possible to intercept such a regular stream of particles entering the fuel volume 15 through the inlet port 18a and convey them to a "safe zone", thus preventing their being carried into the delivery ports and, from there, to the injectors. By intercepting the particles the burden on the injector edge filters is reduced, improving reliability of the injectors.

[0036] Referring next to Figure 3, this illustrates a cross-section through an apparatus embodying a first form of the invention. In the Figures, as far as possible, like reference numerals indicate like parts.

[0037] In the illustrated embodiment, shown generally at 20, the invention consists of a modification to the apparatus of Figures 1 and 2. The apparatus 20 thus comprises rail means in the form of a so-called spherical rail having a common rail or hub 12 with a wall section 14 defining an enclosed fuel volume 15. A plurality of pipes 16a - 16e open into the fuel volume 15 via respective apertures or ports 18a - 18e disposed in the wall section 14. A first one of the pipes 16a represents an inlet or rail entry passage and is connected to, and in fluid communication with, a high pressure fuel pump (not shown) for the supply of high pressure fuel into the fuel volume 15. The remaining pipes 16b - 16e represent outlet or delivery passages, being connected to, and in fluid communication with, an inlet of a respective injector of the engine (not shown) for the supply of fuel from the fuel volume 15 to the injectors. The delivery passages open into the fuel volume at ports 18b-18e, respectively.

[0038] The rail 12 is provided with a filter means in the form of a collector device or receptor 22 disposed within the fuel volume 15. The receptor consists of a convoluted wall 24 defining, together with the wall section 14 of the hub, a U-shaped or C-shaped passage or channel 26 within the fuel volume 15. The channel 26 is open at one end and closed at the other end, as described below.

[0039] The channel 26 includes three regions: a first, inlet region 26a, a second, intermediate region 26b and a third, end region 26c. The first, inlet region 26a includes, at one end thereof, the open end of the channel and is oriented within the fuel volume 15 so that the open end is adjacent to, and directed towards, the inlet port 18a at the end of the inlet passage 16a. For the purpose of this specification, the open end of the channel will also be referred to as being 'aligned with' the inlet port 18a. The first inlet region 26a is funnelled such that it narrows as it extends away from the inlet port 16a. An outer part 24a of the wall 24 bounding the inlet region 26a has a thickness which is greater than that of the inner part of the wall 24b. The bluffed or rounded end of the wall 24a has the beneficial effect of 'smoothing' the flow of fuel into the fuel volume 15.

[0040] The second, intermediate region 26b of the channel 26 is oriented generally at right angles to the first, inlet region 26a and represents the "base" of the U- or C-shape. The outer wall 24c of the intermediate region 26b is provided with a selective barrier means in the form of a sieve or cribriform section 30. The pores or holes within the cribriform section 30 are sized in order to permit fuel to flow out of the channel 26 through the cribriform section 30, but to prevent particles within a predetermined size range from passing therethrough. In particular, the pores are selected so that the cribriform section 30 serves as a barrier to those particles which could cause failure of injectors if permitted to enter the delivery passages 16b - 16e. The orientation and sizing of the cruciform section 30 is such that it does not become 'choked' with particles which it blocks, but serves to dissipate the momentum of impacting particles, thereby preventing their passage therethrough into the rail volume 15 and allowing them to continue through the channel 26 with fuel flow into the quiescent chamber 26c.

[0041] The third, end region 26c is oriented substantially perpendicularly to the second, intermediate region 26b and generally parallel to the first, inlet region 26a. The end region is closed at its end distal to the intermediate region 26b and defines a so-called quiescent chamber 26c within the channel 26, the purpose of which is described below.

[0042] The receptor 22 includes a flow restrictor 32, in the form of a relatively abrupt, narrowed region of the channel 26 disposed at or adjacent to the apex between the inlet region 26a and the intermediate region 26b. In the illustrated embodiment, the narrowed region is formed by two corner pieces 32a, 32b attached to, or formed integrally with, the inner and outer parts 24a, 24b of the wall 24.

[0043] The purpose of the flow restrictor 32 is twofold: firstly, the speed of the fuel flow into the receptor 22 increases temporarily at the narrowed region 32 making it more difficult for particles entering the intermediate region 26b to return into the inlet region 26a past the restrictor 32. Secondly, the restrictor 32 reduces or eliminates resonance or turbulence within the receptor 22 by effectively damping pressure waves generated within the fuel. This reduction or elimination of resonance or turbulence within the receptor improves fuel flow and minimises any adverse impact on the performance of the apparatus due to the presence of the receptor 22 in the fuel volume 15.

[0044] In use, fuel supplied to the rail 12 from the fuel pump enters the fuel volume 15 through the inlet passage 16a and the inlet port 18a. Owing to the reduction in pressure in the fuel as the inlet port 18a opens out into the fuel volume 15, much of the fuel changes direction as it flows through the inlet port 18a and into the fuel volume 15. However, particles present in the fuel which have sufficient mass, and hence inertia, are carried in a generally straight line from the inlet port 18a, through the opening of the receptor 22 and into the inlet region 26a.

[0045] The flow of fuel into the receptor 22 carries the particles through the inlet region, past the restrictor 32 and into the intermediate region 26b. Within the intermediate region 26b, the fuel is able to pass through the pores in the cribriform section 30 and return into the main part of the fuel volume 15 within the rail 12 for delivery to the injectors. Particles in the selected size range, however, are unable to pass through the pores in the cribriform section 30 and are thus trapped and retained within the receptor 22.

[0046] The continuous flow of fuel into the receptor 22 causes these filtered particles to be conveyed past the apex between the intermediate region 26b and the end region and into the quiescent chamber 26c. Since the particles are unable either to pass through the pores in the cribriform section 30, or to return past the restrictor 32, they cannot re-enter the main part of the fuel volume within the rail 12 and thus cannot be conveyed to the injectors. In fact, in the illustrated embodiment, the particles collected by the receptor 22 and deposited in the quiescent chamber 26c are permitted to remain within the receptor for the life of the apparatus.

[0047] The applicants have found that the inclusion of a receptor 22, for example of the type described in the embodiment of Figure 3, within the rail 12 has advantageous effects in terms of common rail performance and injector reliability. Nevertheless, it will be appreciated by those skilled in the art that the embodiment of Figure 3 represents merely one example of a suitable receptor and that various modifications may be made thereto, whilst maintaining the aforementioned advantages.

[0048] For example, the receptor 22 may be integrally formed, for example by casting, into the body or the wall section 14 of the rail 12. Alternatively, the receptor 22 may be formed as a separate element and rigidly connected to the wall section 14 of the rail 12 by means of an arm or the like. The receptor 22 may be non-removable from the rail 12 and arranged to remain within the fuel volume 15 for the life of the rail 12. This is possible since the shape and arrangement of the receptor 22 prevents particles from returning into the fuel volume proper, while the volume of the quiescent chamber may be such that the receptor 22 is unlikely to become saturated with particles during the life of the rail 12.

[0049] The cribriform section 30 may be a separate element located in the wall 24c of the receptor 22 which can be removed for cleaning, if necessary, or may be integrally formed with the wall.

[0050] Figures 4 and 13 illustrate, either in longitudinal or transverse section, a number of alternative embodiments to the invention. Considering firstly Figures 4 and 5, an embodiment is shown in which the receptor comprises a generally cylindrical tubular member, or tube 42, located within the fuel volume 15. A compressed washer 43 locates at the bottom of the volume 15, and this serves to secure the tube 42 in place between the washer 43 and a part of the internal wall 14 at an upper end of the volume 15 (in the orientation shown). The tube 42 is closed at its ends and a tapered aperture or opening 44 extends through the wall of the tube 42 into a fuel volume 46 defined by the tube 42. The aperture 44 is substantially in alignment with the inlet port 18a. With reference to Figure 5, x indicates the diameter of the aperture 44 and y indicates the clearance between the internal wall of the rail 12 and the outer wall of the tube 42.

[0051] As described previously for the embodiment of Figure 3, particles suspended in the fuel entering the common rail 12 are, by their inertia, carried through the aperture 44 and into the volume 46. The weight of the particles causes them to be deposited at the bottom of the volume 46. The positive pressure at the aperture 44 caused by the in-flow of fuel hinders the particles from passing back through the aperture and into the fuel volume 15 from where they may be delivered to the injectors.

[0052] Fuel carrying no, or fewer, particles is delivered to the injectors via the outlet ports 18b - 18e. Any particles remaining in the fuel are delivered through the outlet ports generally randomly, thereby not placing any undue burden on a particular injector.

[0053] By adjusting the values of x and y, that is to say by increasing or decreasing the diameter of the aperture 44 and the clearance between the internal wall of the rail 12 and the outer wall of the tube 42, particles of differing sizes can be filtered or separated from the fuel and collected in the tube.

[0054] Figures 6 and 7 illustrate a modification to the embodiment of Figures 4 and 5. In this embodiment, the tube 42 is provided with an inwardly directed plate or baffle 48 extending from the wall of the tube. The baffle 48 effectively defines a partition between an upper volume 46 of the tube 42 and a quiescent chamber 47 within the tube 42. The quiescent chamber 47 is disposed at the bottom of the tube, the weight of the particles causing them to be deposited in the quiescent chamber.

[0055] Particles entering the upper volume 46 via the aperture 44 are carried past the edge clearance 49 between the end of the baffle 48 and the wall of the tube 42 and into the quiescent chamber 47 where they are trapped by the baffle 48. Again, in-flow of fuel past the edge clearance prevents the particles from passing back out of the quiescent chamber 47.The baffle 48 may be integrally formed with the tube.

[0056] Figures 8 and 9 illustrate a modification to the embodiment of Figures 6 and 7. In this case the receptor is provided with two baffles 48a, 48b which together define a convoluted passage within the tube. The baffles 48a, 48b provide ramps along which the particles are guided and are shaped to minimise the occurrence of collected particles being carried out of the quiescent chamber 47. Again, the edge clearance 49 (the width of the gap between the free ends of the baffles and the wall of the tube 42) may be selected in dependence upon the size of the particles it is desired to collect.

[0057] In Figures 10 and 11, a single baffle 48 is inclined downwardly, thereby acting as a ramp down which collected particles are guided. In this embodiment, however, the baffle 48 is provided with a plurality of slots 50, which extend axially along the length of the baffle 48 between upper and lower ends thereof. The slots 50 define a grid in the baffle 48 and both the width of the slots 50 and the edge clearance 49 determine the size of particles that are collected by the tube 42.

[0058] Finally, in Figures 12 and 13 two baffles 48a, 48b define a guide for inflowing particles and two distinct compartments or chambers 54, 56 joined by a passageway 58. The lower chamber 56 defines a quiescent chamber within which the collected particles are deposited, whilst the upper chamber 54 is provided with a vent or orifice 52, which may be a cribriform section, to allow fuel entering the tube 42, minus any filtered particles it carried initially, to return to the main flow towards the common rail outlet.

[0059] In this embodiment, the length of the tube 42 is significantly reduced, the washer 43 is removed and the tube 42 forms an interference fit within the rail 12.

[0060] The width of the passageway between the upper and lower compartments is defined by the edge clearance and can be selected in dependence on the particle size to be collected.

[0061] It will be appreciated that the present invention provides a relatively simple and inexpensive solution to the problem of injector failure through particle contamination. The provision of a filter means, or receptor, within the common rail itself, being arranged to collect and filter out particles carried within the fuel, ensures that these particles are not carried to the injectors, reducing the burden on the injector edge filters and therefore improving injector reliability.

[0062] In another modification, the rail means 12 may have a plurality of inlets through which high pressure fuel is supplied to the rail volume 15, with the filter means being provided with a corresponding number of openings 26a, 44, each of which is in alignment, that is adjacent to and directed towards, a respective one of the inlets.

[0063] Although the foregoing description has referred to the common rail as being a 'spherical' rail, it will be appreciated that the invention is equally application to other types of accumulator fuel systems where the fuel accumulator volume has a different shape, for example a linear rail volume.

Claims

1. An apparatus for supplying fuel to a plurality of injectors of a combustion engine or the like, the apparatus comprising rail means (12) having an inlet (16a, 18a) for the supply of fuel into the rail means and at least one outlet (16b - 16e, 18b - 18e) for the delivery of fuel to the injectors, wherein the rail means (12) includes filter means (22; 42) for collecting and/or filtering particles carried in the fuel, the filter means (22; 42) being non-removably disposed within the rail means (12) and arranged so that an opening (26a; 44) thereof aligns with the inlet (16a, 18a) to the rail means (12).

2. An apparatus as claimed in claim 1, wherein the rail means (12) includes a wall section (14) defining a fuel volume (15), the filter means (22) being disposed within the fuel volume (15).

3. An apparatus as claimed in claim 2, wherein the filter means includes a tube (42) mounted within the fuel volume (15), the tube (42) having a tube wall provided with the opening (44) which is aligned with the inlet (16a, 18a).

4. An apparatus as claimed in claim 3, wherein the tube (42) is provided with at least one baffle (48; 48a, 48b) to define a partition between an upper volume (46) of the tube (42) and a quiescent chamber (47) of the tube (42).

5. An apparatus as claimed in claim 4, wherein the baffle (48) is provided with a plurality of slots (50) to define a baffle grid.

6. An apparatus as claimed in claim 5, comprising first and second baffles (48a, 48b) to define first and second distinct chambers (54, 56), the first chamber defining the quiescent chamber for collecting particles therein.

7. An apparatus as claimed in claim 6, wherein the second chamber includes a vent (52) to allow fuel to flow out of the tube (42).

8. An apparatus as claimed in claim 7, wherein the vent (52) takes the form of a cruciform section.

9. An apparatus as claimed in claim 2, wherein the filter means (22) comprises a wall (24) defining a channel (26) having an opening at one end thereof for the passage of fuel therein.

10. An apparatus as claimed in claim 9, wherein the filter means (22) is integrally formed with the wall section (14).

11. An apparatus as claimed in claim 10, wherein the channel (26) comprises three channel regions (26a, 26b, 26c) arranged substantially in a U-shape or a C-shape.

12. An apparatus as claimed in claim 11, wherein a first one (26a) of the channel regions has the opening (26a) at one end thereof and tapers towards the other end thereof.

13. An apparatus as claimed in claim 12, wherein a second one of the channel regions (26b) is oriented generally perpendicularly to the first channel region (26a).

14. An apparatus as claimed in claim 13, wherein the second one (26b) of the channel regions includes selective barrier means (30) disposed in the wall (24) for permitting fuel to flow from the channel (26) into the fuel volume (15) but to prevent particles of a predetermined size from passing therethrough.

15. An apparatus as claimed in claim 14, wherein the selective barrier means comprise a cribriform section (30).

16. An apparatus as claimed in any one of claims 11 to 15, wherein a third one (26c) of the channel regions is oriented generally perpendicularly to the second channel region (26b) and substantially parallel to the first channel region (26a), the third channel region (26c) being closed at one end and defining a quiescent chamber within the channel (26).

17. An apparatus as claimed in claim 16, wherein the quiescent chamber (26c) is arranged to collect and retain said particles therein.

18. An apparatus as claimed in any one of claims 9 to 17 wherein the filter means (22) includes restrictor means (32a, 32b) disposed within the channel (26) for reducing or damping pressure waves within the fuel.

19. An apparatus as claimed in claim 18, wherein the restrictor means consists of a narrowed region of the channel (26).

20. An apparatus for supplying fuel to a plurality of injectors of a combustion engine or the like, the apparatus comprising a rail volume (15) including a region of part-spherical form, the rail volume (15) having at least one inlet (16a, 18a) for the supply of fuel into the rail volume (15) and at least one outlet (16b-16e, 18b-18e) for the delivery of fuel at an injectable pressure level to the injectors, wherein the rail volume (15) includes a filter means (42) for filtering and/or collecting particles carried in the fuel, the filter means including a tubular member (42) having a tube wall provided with an opening (44) in alignment with the inlet (16a, 18a).

Amended claims

Amended claims in accordance with Rule 86(2) EPC.

16. An apparatus as claimed in any one of claims 11 to 15, wherein a third one (26c) of the channel regions is oriented generally perpendicularly to the second channel region (26b) and substantially parallel to the first channel region (26a), the third channel region (26c) being closed at one end and defining a quiescent chamber within the channel (26).

17. An apparatus as claimed in claim 16, wherein the quiescent chamber (26c) is arranged to collect and retain said particles therein.

18. An apparatus as claimed in any one of claims 9 to 17 wherein the filter means (22) includes restrictor means (32a, 32b) disposed within the channel (26) for reducing or damping pressure waves within the fuel.

19. An apparatus as claimed in claim 18, wherein the restrictor means consists of a narrowed region of the channel (26).

Drawing