EP4735753A1

EP4735753A1 - A fuel rail assembly

Info

Publication number: EP4735753A1
Application number: EP24740497.3A
Authority: EP
Inventors: Thomas Peter RANDLES; Chunxing LIN; Saifullah Khan
Original assignee: Jcb Research
Current assignee: Jcb Research
Priority date: 2023-06-29
Filing date: 2024-06-26
Publication date: 2026-05-06
Also published as: GB202309838D0; GB2631412A; CN121420131A; WO2025003653A1

Abstract

A fuel rail assembly (118) comprising: a fuel rail (120); an adaptor (126); a fuel supply line (160); and a releasable coupling arrangement (162) for releasably coupling the fuel supply line (160) to the adaptor (126). The fuel rail (120) comprises a fuel supply passage (122) by which fuel is supplied to said at least one fuel injector (124). The adaptor (126) comprises a body (128) including an inlet (130). The adaptor (126) is mounted to the fuel rail (120) such that the inlet (130) is in fluid communication with the fuel supply passage (122). The fuel supply line (160) comprises a fuel orifice (164). The fuel supply line (160) is releasably coupled to the adaptor (126) via the releasable coupling arrangement (162) such that the fuel orifice (164) is in fluid communication with the inlet (130) for supplying fuel from the fuel orifice (164) to the fuel supply passage (122) via the inlet (130).

Description

A FUEL RAIL ASSEMBLY

FIELD

The present teachings relate to a fuel rail assembly for an internal combustion engine, an internal combustion engine, and a method of releasably coupling a fuel supply line to a fuel rail of an internal combustion engine.

BACKGROUND

It is known to filter fuel (whether liquid or gaseous fuel) in internal combustion engines so as to remove contaminants (e.g. dust, dirt, foreign particles) from the fuel in order to maintain performance of the engine. For example, in fuel-injected internal combustion engines in which fuel is injected into a combustion chamber or an inlet tract upstream of a combustion chamber via one or more fuel injectors, filtering the fuel before the fuel is supplied to the one or more fuel injectors helps to maintain the durability and performance of the one or more fuel injectors, which are commonly prone to clogging and/or damage by contaminants in fuel.

To filter fuel, internal combustion engines typically include a fuel filtering unit upstream of the combustion chambers and any fuel injectors. Such fuel filtering units commonly include a fuel filter housed within a dedicated housing.

A problem with such fuel filtering units is that they tend to be relatively bulky, which increases the required space envelope of the engine and makes packaging of the engine more complex. Moreover, connections between the fuel filtering unit and the engine's fuel supply lines increases the number of leakage points in the engine prone to leaking fuel.

The present teachings seek to overcome or at least mitigate one or more problems associated with the prior art.

SUMMARY

According to a first aspect of the present teachings, there is provided a fuel rail assembly for an internal combustion engine, the fuel rail assembly comprising: a fuel rail for supplying fuel to at least one fuel injector; and an adaptor for connecting the fuel rail to an upstream fuel line. The fuel rail comprises a fuel supply passage by which fuel is supplied to said at least one fuel injector. The adaptor comprises a body including an inlet. The inlet is couplable to said upstream fuel line. The adaptor is mounted to the fuel rail such that the inlet is in fluid communication with the fuel supply passage. The adaptor further comprises a fuel filter for filtering fuel flowing from the inlet to the fuel supply passage. The fuel filter is housed at least partially within the body.

At least partially housing the fuel filter within the body allows the fuel rail assembly to be more compact than a fuel filter provided as part of a fuel filtering unit separate to the adaptor. In addition, the number of potential leakage points (i.e. points where different fuel line components are secured together) may be reduced relative to a fuel filter provided as part of such a separate fuel filtering unit. Housing the fuel filter within the adaptor, which is mounted to the fuel rail, advantageously allows the length of piping between the fuel filter and the one or more fuel injectors to be shorter relative to an arrangement where the fuel filter is separate to, and upstream of, the adaptor. A shorter length of piping helps to minimise the amount of contaminants in the fuel reaching the one or more fuel injectors, which are vulnerable to damage by fuel contaminants.

The fuel filter may be mounted to the body.

Advantageously, mounting the fuel filter to the body enables the fuel filter to be preassembled with the adaptor, easing assembly of the fuel rail assembly.

The fuel filter may be releasably mounted to the body.

Advantageously, releasably mounting the fuel filter to the body enables the fuel filter to be released from the body for inspection, maintenance or replacement.

The fuel filter may be releasably mounted to the body via a releasable mounting arrangement including complementary screw threads on the body and the fuel filter.

The body may be configured such that the fuel filter is receivable within the body via the inlet for mounting the fuel filter to the body.

The fuel filter and the body may be configured such that the fuel filter is inhibited from passing through the inlet when mounting the fuel filter to the body.

Advantageously, configuring the fuel filter and the body such that the fuel filter is inhibited from passing through the inlet when mounting the fuel filter to the body helps to inhibit users from removing the fuel filter from the body (e.g. to tamper with it), since a user may be required to conduct an additional process of removing the adaptor from the fuel rail before the fuel filter can be removed from the body.

The fuel filter may be elongate and comprise opposing first and second longitudinal ends. The first longitudinal end may be mounted to the body. Advantageously, such a configuration simplifies assembly of the adaptor.

The second longitudinal end may be a free end.

The body may comprise an outlet arranged such that fuel flows from the inlet to the outlet and then to the fuel supply passage, in use. The fuel filter may be mounted to the outlet.

Advantageously, such a configuration simplifies assembly of the adaptor, and enables the adaptor to be more compact.

Fuel may flow from the inlet to the fuel filter, then to the outlet and then to the fuel supply passage, in use.

The fuel filter may comprise an elongate filtering portion configured to filter fuel flowing from the inlet to the fuel passage, in use.

Advantageously, such a configuration may increase the surface area of the fuel filter exposed to fuel, which may reduce the pressure drop of fuel flowing through the adaptor.

The filtering portion may be substantially cylindrical.

The body may be elongate. A longitudinal axis of the body may be substantially aligned with a longitudinal axis of the filtering portion.

Advantageously, such a configuration helps to reduce the required space envelope of the adaptor, by reducing a thickness/width of the adaptor.

A portion of the fuel filter may be located within the fuel supply passage.

Advantageously, such a configuration helps to reduce the required space envelope of the adaptor, by reducing a length of the adaptor.

The adaptor may comprise a sealing arrangement between the fuel filter and the body configured to inhibit fuel flowing from the inlet to the fuel supply passage bypassing the fuel filter.

Advantageously, the sealing arrangement helps to inhibit unfiltered fuel from flowing to the fuel supply passage.

The sealing arrangement may comprise a seal member, such as an O-ring, and/or a sealant, between the body and the fuel filter.

The fuel filter may be wholly housed within the body. Advantageously, such a configuration improves protection for the fuel filter from external damage prior to assembly of the fuel rail assembly.

The fuel rail assembly may further comprise a releasable mounting arrangement. The body may be releasably mounted to the fuel rail via the releasable mounting arrangement.

Advantageously, such a configuration enables the adaptor to be removed from the fuel rail for inspection or maintenance.

The releasable mounting arrangement may comprise a first engaging portion of the body and a second engaging portion of the fuel rail. Engagement of the first and second engaging portions with each other may releasably mount the body to the fuel rail.

The first and second engaging portions may comprise complementary screw threads.

A profile of the adaptor in a plane normal to a screw axis of the body may have a polygonal shape for engagement with a torque application tool such as a wrench or spanner.

A profile of the body in a plane normal to a screw axis of the body may have a polygonal shape for engagement with a torque application tool such as a wrench or spanner.

The first engaging portion on the body may be a male portion. The second engaging portion on the fuel rail may be a female portion configured to receive the male portion.

Advantageously, such a configuration enables the adaptor to be more compact.

The second engaging portion on the fuel rail may be a male portion. The first engaging portion on the body may be a female portion configured to receive the male portion.

The fuel rail assembly may further comprise a sealing arrangement between the body and the fuel rail configured to inhibit fuel exiting the fuel rail assembly via the releasable mounting arrangement.

The seal arrangement may be configured to inhibit fuel flowing from the inlet to the fuel supply passage contacting the first and second engaging portions.

Advantageously, such a configuration may help to inhibit contaminants from entering the fuel.

The seal arrangement may comprise a seal member, such as an O-ring.

The seal member may be coupled to the body or the fuel rail. The seal member may be received in a circumferential recess in the body or the fuel rail.

The body may be formed as a single monolithic piece of material.

Advantageously, such a configuration helps to reduce the number of components in the fuel rail assembly, simplifying assembly thereof.

The body may be formed from a metal material such as steel, e.g. stainless steel.

The adaptor may extend from the fuel supply passage such that a longitudinal axis of the adaptor is at a non-zero angle to a longitudinal axis of the fuel supply passage.

The non-zero angle may be in the range of 45 to 90 degrees.

The longitudinal axis of the adaptor may be substantially perpendicular to the longitudinal axis of the fuel supply passage.

The fuel filter may be a gaseous fuel filter.

The fuel filter may be a hydrogen fuel filter.

The adaptor may be elongate and have a length and a maximum width transverse to the length. The length may be in the range of 30mm to 70mm, optionally 40mm to 60mm, for example approximately 47mm. The maximum width may be in the range of 15mm to 35mm, optionally 20mm to 30mm, for example approximately 26mm.

According to a second aspect of the present teachings, there is provided a fuel rail assembly for an internal combustion engine, the fuel rail assembly comprising: a fuel rail for supplying fuel to at least one fuel injector; an adaptor for connecting the fuel rail to an upstream fuel line; a first fuel supply line for supplying fuel to the adaptor; and a releasable coupling arrangement for releasably coupling the first fuel supply line to the adaptor. The fuel rail comprises a fuel supply passage by which fuel is supplied to said at least one fuel injector. The adaptor comprises a body including an inlet. The adaptor is mounted to the fuel rail such that the inlet is in fluid communication with the fuel supply passage. The first fuel supply line comprises a fuel orifice. The first fuel supply line is releasably coupled to the adaptor via the releasable coupling arrangement such that the fuel orifice is in fluid communication with the inlet for supplying fuel from the fuel orifice to the fuel supply passage via the inlet.

Advantageously, the releasable coupling arrangement may enable the first fuel supply line to be rapidly and securely coupled to the adaptor. This is particularly beneficial for when the first fuel supply line is to be coupled to the adaptor for a relatively short amount of time (e.g. during hot testing of an engine).

The releasable coupling arrangement may comprise a first locking member on the adaptor and a second locking member on the first fuel supply line. The first and second locking members may be arranged to engage so as to releasably couple the fuel line to the body.

The first locking member may be fixed relative to the body. The second locking member may be moveable relative to the fuel orifice between unlocked and locked positions. The first locking member may comprise a first engaging surface. The second locking member may comprise a second engaging surface. The first and second engaging surfaces may be engageable so as to releasably couple the fuel line to the body when the second locking member is in the locked position.

Advantageously, such a configuration enables the first fuel supply line to be rapidly and securely coupled to the body.

The first locking member may be a circumferential recess or collar comprising the first engaging surface.

The body may comprise the first locking member.

The second locking member may be biased towards the locked position.

Advantageously, such a configuration helps to maintain a secure coupling between the first fuel supply line and the body.

The second locking member may be pivotable relative to the fuel orifice between the unlocked and locked positions.

The releasable coupling arrangement may comprise a release mechanism configured to selectively move the second locking member between the unlocked and locked positions.

Advantageously, such a configuration enables the first fuel supply line to be rapidly coupled to and uncoupled from the body.

The release mechanism may comprise a release member movable between a first position, in which the second locking member is retained in the locked position, and a second position in which the second locking member is moved to the unlocked position.

The release member may be biased towards and/or selectively retained in the first position. The releasable coupling arrangement may be configured such that, when respective axes of the adaptor and the fuel line are substantially aligned, and the fuel orifice and the inlet are translated together along said respective axes, the second locking member moves over the first locking member such that the first and second engaging surfaces are engageable.

Advantageously, such a configuration enables the first fuel supply line to be rapidly coupled to the body.

The releasable coupling arrangement may comprise a plurality of the first locking members and a corresponding plurality of the second locking members.

Advantageously, such a configuration helps to provide a strong coupling between the first fuel supply line and the body.

The first locking members may be distributed about a longitudinal axis of the body. The second locking members may be distributed about a longitudinal axis of the first fuel supply line.

The fuel rail assembly may further comprise a guide arrangement configured to guide relative movement between the body and the first fuel supply line such that the first and second locking members are engageable so as to releasably couple the fuel line to the body.

The guide arrangement may comprise a recess in the first fuel supply line configured to receive a protrusion of the adaptor. The recess and the protrusion may have complementary profiles.

The fuel rail assembly may further comprise a sealing arrangement between the first fuel supply line and the body configured to inhibit fuel exiting the fuel rail assembly via the releasable coupling arrangement.

The seal arrangement may comprise a seal member, such as an O-ring.

The seal member may be coupled to the fuel line.

The fuel orifice may be received in the inlet. The sealing arrangement may be between an external surface of the first fuel supply line and a first internal surface of the body.

The external surface of the first fuel supply line and the first internal surface of the body may have complementary profiles. The body may comprise a second internal surface for forming a seal between the body and a second fuel supply line for supplying fuel to the fuel rail during normal use of the engine. The second internal surface may be adjacent the first internal surface. The fuel rail assembly may be configured such that the first fuel supply line is inhibited from contacting the second internal surface when the first fuel supply line is coupled to the body.

Advantageously, such a configuration helps to inhibit the first fuel supply line from damaging the second inner surface, which may be a sealing surface for a second fuel supply line for example.

The guide arrangement may be configured to inhibit the first fuel supply line from contacting the second internal surface.

The second internal surface may be axially outboard of the first internal surface.

The second internal surface may be tapered.

The adaptor may comprise a fuel filter at least partially housed within the body. The fuel filter may be configured to filter fuel flowing from the inlet to the fuel supply passage, in use.

According to a third aspect of the present teachings, there is provided an internal combustion engine comprising the fuel rail assembly according to the first or second aspects.

The internal combustion engine may be a gaseous fuel internal combustion engine, e.g. a hydrogen fuel internal combustion engine.

According to a fourth aspect of the present teachings, there is provided a method of releasably coupling a fuel supply line to a fuel rail of an internal combustion engine. The fuel rail is for supplying fuel to at least one fuel injector. The fuel rail comprises a fuel supply passage by which fuel is supplied to said at least one fuel injector. The method comprises the steps of: providing an adaptor for connecting the fuel rail to an upstream fuel line, the adaptor comprising a body including an inlet; mounting the adaptor to the fuel rail such that the inlet is in fluid communication with the fuel passage; providing a fuel supply line for supplying fuel to the adaptor, the fuel supply line comprising a fuel orifice; and releasably coupling the fuel supply line to the adaptor via a releasable coupling arrangement such that the fuel orifice is in fluid communication with the inlet for supplying fuel from the fuel orifice to the fuel supply passage via the inlet.

The releasable coupling arrangement may comprise a first locking member on the adaptor and a second locking member on the fuel line. The first and second locking members may be arranged to engage so as to releasably couple the fuel line to the body.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments are now disclosed by way of example only with reference to the drawings, in which:

Figure 1 is an isometric view of an internal combustion engine according to an embodiment;

Figure 2 is a front isometric view of an intake assembly of the internal combustion engine of Figure 1;

Figure 3 is a rear isometric view of the intake assembly of Figure 2 coupled to a cylinder head of the internal combustion engine of Figure 1;

Figure 4 is a cross-sectional view of a fuel rail assembly of the intake assembly of Figure 2 in an assembled state;

Figure 5 is a cross-sectional view of the fuel rail assembly of Figure 4 in a disassembled state;

Figure 6 is a magnified cross-sectional view of an adaptor of the fuel rail assembly of Figures 4 and 5;

Figure 7 is an isometric view of the adaptor of Figure 6 coupled to a fuel supply line;

Figure 8 is a cross-sectional view along section X-X shown in Figure 7; and

Figure 9 is a cross-sectional view of a fuel rail assembly according to an embodiment.

DETAILED DESCRIPTION OF EMBODIMENT(S)

In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of various embodiments and the inventive concept. However, those skilled in the art will understand that: the present invention may be practiced without these specific details or with known equivalents of these specific details; that the present invention is not limited to the described embodiments; and, that the present invention may be practiced in a variety of alternative embodiments. It will also be appreciated that well known methods, procedures, components, and systems may not have been described in detail.

Figure 1 shows an internal combustion engine 100 according to an embodiment. The engine 100 is a gaseous fuel engine configured to be powered by a gaseous fuel, such as hydrogen, compressed natural gas (CNG), landfill gas or the like. In the illustrated embodiment, the engine 100 is powered by hydrogen. In alternative embodiments, the engine 1 may be configured to be powered by liquid fuels such as petroleum (gasoline) or diesel for example, or by a combination of liquid and gaseous fuels. The engine 100 in this embodiment has four cylinders, but in other embodiments may have more or fewer cylinders, e.g. 2, 3, 6, or 8. In addition in other embodiments the cylinders may be oriented in a "V" or boxer configuration rather than inline as in the disclosed embodiment.

The engine 100 may be suitable for use as the prime mover in a working machine (not shown), such as a telescopic handler, a forklift truck, a backhoe loader, a wheeled loading shovel, a dumper, an excavator or a tractor, for example. Such working machines are suitable for use in off-highway industries such as agriculture and construction. In these industries they are generally configured to perform tasks such as excavation, load handling, harvesting or planting crops. The engine 100 may also be utilised in a genset - a self-contained unit to provide electrical power at off-grid locations. As such the engine 100 is typically required to have certain characteristics such as a high torque output over a wide engine speed band, with peak torque occurring at a relatively low engine speed, which differ from light passenger vehicles, for example. In off-highway applications, this provides "torque backup" that enables working machines to continue to carry out working operations when encountering increased loads, or resistance to a working operation - e.g. an excavator encountering a particularly solid piece of earth to be excavated.

In the present embodiment, the engine 100 has a total displacement of 4.4 litres (i.e. 1.1 litres per cylinder). In engines used in off-highway applications each cylinder may typically have a displacement of between 0.75 and 1.25 litres. Such a displacement is relatively high by comparison with passenger vehicle engines, but is suited to providing the operating characteristics described above.

The engine 100 includes an intake assembly 102, a cylinder head 104, and a cylinder block 106. The cylinder head 104 is mounted to the cylinder block 106. The intake assembly 102 is mounted to the cylinder head 3. The engine 100 is configured such that the intake assembly 102 supplies a mixture of air and fuel to a plurality of intake ports of the cylinder head 104. The air-fuel mixture is then supplied from the intake ports to corresponding cylinders of the cylinder block 106 in a known manner. As such, the engine 100 is a port fuel injection engine (i.e. fuel is provided to the cylinders 5 via port fuel injection). In alternative embodiments (not shown), the engine 100 may be a direct injection engine, or may employ a combination of port fuel injection and direct injection.

With further reference to Figures 2 and 3, the intake assembly 102 includes an intake manifold 110. The intake manifold 110 includes a plenum 112 (U-shaped in the illustrated embodiment), and a plurality of intake runners 114. The intake runners 114 are configured to be couplable to the cylinder head 104 for supplying an air-fuel mixture to the intake ports. The intake manifold 110 includes an air supply inlet 116. The intake manifold 110 is configured such that, in use, air is supplied from the air supply inlet 116 to the intake runners 114 via the plenum 112.

The intake assembly 102 includes a fuel rail assembly 118. The fuel rail assembly 118 includes a fuel rail 120 for supplying fuel to a plurality of fuel injectors 124. The fuel rail 120 is couplable to the fuel injectors 124. The fuel rail 120 includes a fuel supply passage 122 by which fuel is supplied to the fuel injectors 124. In the illustrated embodiment, the fuel rail 120 supplies fuel to four fuel injectors 124 corresponding to the four cylinders in the cylinder block 106. In alternative embodiments (not shown), the fuel rail 120 may supply fuel to less than or more than four fuel injectors 124, e.g. one or more fuel injectors 124.

The fuel injectors 124 are configured to selectively inject a fuel into one of the intake runners 114 with appropriate timing for the combustion cycle in the corresponding cylinder of the cylinder block 106.

In the illustrated embodiment, the fuel rail 120 supplies hydrogen to the fuel injectors 124. Each fuel injector 124 is configured to inject hydrogen into the respective intake runner 114.

In alternative embodiments (not shown), the fuel rail 120 supplies any gaseous fuel, or a liquid fuel, such as gasoline (petroleum) or diesel, to the fuel injectors 124, and the fuel injectors 124 may be configured to inject said gaseous or liquid fuel into the respective intake runner 114.

With further reference to Figures 4, 5 and 6, the fuel rail assembly 118 includes an adaptor 126 for connecting the fuel rail 120 to an upstream fuel line 160 (see Figures 7 and 8). The adaptor 126 includes a body 128. The body 128 includes an inlet 130 configured to be couplable to the upstream fuel line 160, which in some embodiments may be in fluid communication with a fuel tank for storing fuel. The adaptor 126 is mounted to the fuel rail 120 such that the inlet 130 is in fluid communication (e.g. sealed fluid communication) with the fuel supply passage 122. As such, the adaptor 126 enables fuel to be supplied to the fuel rail 120 for supply to the fuel injectors 124 via the upstream fuel line 160 coupled to the inlet 130 of the adaptor 126.

The adaptor 126 includes a fuel filter 132 for filtering fuel flowing from the inlet 130 to the fuel supply passage 122. The fuel filter 132 is housed at least partially within the body 128.

By 'housed at least partially within the body 128', it is intended to mean that at least a portion of the fuel filter 132 is located within the body 128 and is surrounded by the body 128, e.g. so that the body 128 offers some protection to the fuel filter 132.

In the illustrated embodiment, the fuel filter 132 is wholly housed within the body 128; i.e. all of the fuel filter 132 is located within the body 128 and is surrounded by the body 128. Such a configuration helps to inhibit users from tampering with (and thus potentially damaging) the fuel filter 132 during normal use.

In alternative embodiments (not shown), a portion of the fuel filter 132 may not be housed within the body 128. For example, said portion may protrude from the body 128.

The fuel filter 132 is configured to filter fuel flowing from the inlet 130 to the fuel supply passage 122, in use. Put another way, the fuel filter 132 is configured to remove contaminants such as dirt, sediment, dust, or foreign (e.g. metal) particles (e.g. generated from moving parts of the engine 100 that the fuel contacts, and/or that are present in the fuel before introduction into the engine 100), from fuel flowing from the inlet 130 to the fuel supply passage 122, in use.

At least partially housing the fuel filter 132 within the body 128, allows the fuel rail assembly 118, and thus the engine 100, to be more compact relative to an arrangement where the fuel filter is provided as part of a fuel filtering unit separate to the adaptor 126. In such an arrangement, an adaptor between the fuel rail and an upstream fuel line would still be required. Moreover, the number of leakage points (i.e. located where different fuel line components are secured together) may be reduced relative to if the fuel filter was provided as part of such a separate fuel filtering unit. Further, by housing the fuel filter 132 within the adaptor 126 mounted to the fuel rail 120, the length of piping between the fuel filter 132 and the fuel injectors 124 is shorter relative to if the fuel filter 132 was separate from and upstream of the adaptor 126. This helps to minimise the amount of contaminants in the fuel reaching the fuel injectors 124.

In the illustrated embodiment, the fuel filter 132 is a hydrogen fuel filter. In alternative embodiments, the fuel filter 132 may be any gaseous or liquid fuel filter. In the illustrated embodiment, the fuel filter 132 includes a fine metallic mesh configured to filter fuel passing through the mesh. In exemplary embodiments, the mesh may have a mesh size in the range of 2 to 30 microns, for example approximately 10 microns.

In alternative embodiments, the fuel filter 132 may include any suitable filter, such as a fuel filter formed from paper, cellulose, and/or a suitable synthetic material, for example.

The adaptor 126 is mounted to the fuel rail 120 such that the adaptor 126 extends from the fuel supply passage 122. By 'mounted', it is intended to mean that the adaptor 126 is connected to and supported by the fuel rail 120.

The adaptor 126 extends from the fuel supply passage 122 such that a longitudinal axis Al of the adaptor 126 is at a non-zero angle to a longitudinal axis of the fuel supply passage 122. In the illustrated embodiment, the longitudinal axis Al of the adaptor 126 is substantially perpendicular to the longitudinal axis of the fuel supply passage 122. In alternative embodiments, the non-zero angle may be in the range of 45 to 90 degrees.

The fuel rail 120 includes a connector 133 mounted to the fuel supply passage 122. In the illustrated embodiment, the connector is in the form of a boss extending from the fuel supply passage 122. The adaptor 126 is mounted to the fuel rail 120 via the connector 133. The connector 133 is configured such that the longitudinal axis Al of the adaptor 126 is substantially perpendicular to the longitudinal axis of the fuel supply passage 122. In alternative embodiments (not shown), the adaptor 126 may be mounted to the fuel rail 120 via any suitable means, e.g. the adaptor 126 may be mounted directly to the fuel supply passage 122.

The fuel rail assembly 118 includes a releasable mounting arrangement 142. The body 128 is releasably mounted to the fuel rail 120 via the releasable mounting arrangement 142. By 'releasably mounted' it is intended to mean that, once mounted, the body 128 can be released from the fuel rail 120 by hand or using one or more tools (e.g. a spanner, a wrench, a screwdriver, and/or a specialised tool) without damaging either the body 128 or the fuel rail 120.

In alternative embodiments (not shown), the body 128 may be mounted to the fuel rail 120 so as not to be releasable therefrom by hand or using tools without damaging either the body 128 or the fuel rail 120. For example, the body 128 may be bonded or welded to the fuel rail 120.

The releasable mounting arrangement 142 includes a first engaging portion 144 of the body 128, and a second engaging portion 146 of the connector 133. The releasable mounting arrangement 142 is configured such that engagement of the first and second engaging portions 144, 146 with each other releasably mounts the body 128 to the fuel rail 120. In alternative embodiments (not shown), the releasable mounting arrangement 142 may have any suitable configuration.

In the illustrated embodiment, the first and second engaging portions 144, 146 include complementary screw threads, i.e. configured for engagement with each other. In alternative embodiments (not shown), the first and second engaging portions 144, 146 may have any suitable configuration, e.g. such as complementary parts of a bayonet-type fitting.

In the illustrated embodiment, the first engaging portion 144 is a male portion, and the second engaging portion 146 is a female portion configured to receive the male portion. As such, the body 128 is partially within the fuel rail 120, which helps to enhance the compactness of the fuel rail assembly 118.

The body 128 includes a stop 147 configured to abut against the connector 133 of the fuel rail 120 when a predetermined length of the body 128 is received in the connector 133. In the illustrated embodiment, the stop 147 is a flange extending radially outward relative to the first engaging portion 144. The stop 147 is adjacent the first engaging portion 144.

To mount the body 128 to the fuel rail 120 in the illustrated embodiment, body 128 is rotated about the longitudinal axis Al, which corresponds to a screw axis of the body 128 in the illustrated embodiment, such that the threads of the first and second engaging portions 144, 146 engage with each other until the stop 147 contacts the connector 133. To aid this, the stop 147 has a profile in a plane normal to the screw axis Al having a polygonal shape (e.g. rectangular, hexagonal, octagonal) for engaging a torque application tool such as a wrench or spanner. In alternative embodiments (not shown), any suitable portion of the body 128 or the adaptor 126 may have said polygonal shaped profile.

With further reference to Figure 5, the fuel rail assembly 118 includes a sealing arrangement 148 between the body 128 and the fuel rail 120 configured to inhibit fuel exiting the fuel rail assembly 118 via the releasable mounting arrangement 142. The sealing arrangement 148 includes a seal member 150, which in the illustrated embodiment is an O-ring. The seal member 150 is arranged to form a seal between the body 128 and the fuel rail 120 when the first and second engaging portions 144, 146 are engaged with each other and the stop 147 contacts the fuel rail 120.

In alternative embodiments, the sealing arrangement 148 may include any suitable seal member and/or a sealant (e.g. a silicone-based sealant) between the body 128 and the fuel rail 120. Additionally or alternatively, the sealing arrangement 148 may include a cone sealing arrangement between the body 128 and the fuel rail 120.

The seal member 150 is coupled to the body 128, which helps to simplify assembly of the fuel rail assembly 118. In the illustrated embodiment, the seal member 150 is received in a circumferential recess in the body 128, such that the seal member 150 is coupled to the body 128. The circumferential recess is adjacent the stop 147. In alternative embodiments (not shown), the seal member 150 may be coupled to the body 128 via any suitable means. Alternatively, the seal member 150 may be coupled to the fuel rail 120, e.g. the connector 133.

In the illustrated embodiment, the fuel filter 132 is wholly located outside of the fuel supply passage 122. In alternative embodiments (not shown), at least a portion of the fuel filter 132 may be located within the fuel supply passage 122. For example, the stop 147 and the connector 133 may be configured such that when the first and second engaging portions 144, 146 are engaged with each other and the stop 147 contacts the connector 133, portions of the body 128 and the fuel filter 132 protrude into the fuel supply passage 122. Advantageously, the length of the adaptor 126 may be reduced if at least a portion of the fuel filter 132 is located within the fuel supply passage 122, enhancing the compactness of the fuel rail assembly 118.

With further reference to Figure 6, the fuel filter 132 is releasably mounted to the body 128 via a releasable mounting arrangement 134. By 'releasably mounted' it is intended to mean that, once mounted, the fuel filter 132 can be released from the body 128 by hand or using one or more tools without damaging either the body 128 or the fuel filter 132. In the illustrated embodiment, the releasable mounting arrangement 134 includes complementary screw threads on the body 128 and the fuel filter 132 configured such that engagement of the screw threads with each other releasably mounts the fuel filter 132 to the body 128.

In alternative embodiments (not shown), the releasable mounting arrangement 134 may have any suitable configuration. For example, the fuel filter 132 may be releasably mounted to the body 128 via an interference fit. Alternatively, in some embodiments, the fuel filter 132 may be mounted to the body 128 so as not to be releasable therefrom by hand or using tools without damaging either the body 128 or the fuel filter 132. For example, the fuel filter 132 may be bonded or welded to the body 128. Alternatively, the fuel filter 132 may not be mounted to the body 128. The fuel filter 132 is elongate and includes opposing first and second longitudinal ends 132a, 132b. The first end 132a is mounted to the body 128. In the illustrated embodiment, the second longitudinal end 132b is a free end.

The fuel filter 132 may include a recess arrangement at the first end 132a and/or the second end 132b configured to receive a head of a tool (e.g. a screwdriver or Allen key) for mounting the fuel filter 132 to, and releasing the fuel filter 132 from, the body 128.

The body 128 includes an outlet 136 arranged such that fuel flows in from the inlet 130 to the outlet 136 and then to the fuel supply passage 122, in use. The first end 132a of the fuel filter 132 is mounted to the outlet 136. In the illustrated embodiment, the adaptor 126 is configured such that fuel flows from the inlet 130 to the fuel filter 132, then to the outlet 136 and then to the fuel supply passage 122, in use.

In alternative embodiments (not shown), the second end 132b of the fuel filter 132 may alternatively or additionally be mounted to the body 128.

The fuel filter 132 and the body 128 are configured such that the fuel filter 132 is inhibited from passing through the outlet 136 when mounting the fuel filter 132 to the body 128. By 'inhibited from passing through the outlet 136', it is intended to mean that at least a portion of the fuel filter 132 is inhibited from passing through the outlet 136. As such, the fuel filter 132 is passed through the inlet 130 when mounting the fuel filter 132 to the body 128. In the illustrated embodiment, the fuel filter 132 is inhibited from passing through the outlet 136 when releasing the fuel filter 132 from the body 128. The fuel filter 132 includes a first abutment surface 137, and the body 128 includes a second abutment surface 139. The first and second abutment surfaces 137, 137 are arranged to abut against each other to inhibit the fuel filter 132 passing through the outlet 136 when mounting the fuel filter 132 to, and releasing the fuel filter 132 from, the body 128. In the illustrated embodiment, the first abutment surface 137 is a surface of a collar of the fuel filter 132. The second abutment surface 139 is a surface of a rim of the body 128.

In alternative embodiments (not shown), the fuel filter 132 and the body 128 may be configured such that the fuel filter 132 is inhibited from passing through the inlet 130 when mounting the fuel filter 132 to the body. As such, the fuel filter 132 is passed through the outlet 136 when mounting the fuel filter 132 to the body 128. In such embodiments, the fuel filter 132 may be inhibited from passing through the inlet 130 when releasing the fuel filter 132 from the body 128. The first and second abutment surfaces 137, 139 may be configured so as to abut against each other to inhibit the fuel filter 132 passing through the inlet 130 when mounting the fuel filter 132 to, and releasing the fuel filter 132 from, the body 128. Advantageously, configuring the fuel filter 132 and the body 128 as such helps to inhibit users from removing the fuel filter 132 from the body 128 and tampering with the fuel filter 132, since a user is required to conduct an additional process of removing the adaptor 126 from the fuel rail 120 before the fuel filter 132 can be removed from the body 128.

The adaptor 126 includes a sealing arrangement 138 between the fuel filter 132 and the body 128 configured to inhibit fuel flowing from the inlet 130 to the fuel supply passage 122 bypassing the fuel filter 132. In the illustrated embodiment, the sealing arrangement 138 includes a sealant, such as thread seal tape, between the complementary screw threads on the body 128 and the fuel filter 132. In alternative embodiments (not shown), the sealing arrangement 138 may include any suitable sealant and/or a seal member, such as an O-ring, between the body 128 and the fuel filter 132.

The fuel filter 132 includes an elongate filtering portion 140 configured to filter fuel flowing from the inlet 130 to the fuel supply passage 122, in use. In the illustrated embodiment, the filtering portion 140 is a substantially cylindrical wall. In alternative embodiments, the filtering portion 140 may have any suitable shape.

The body 128 of this embodiment is elongate. As shown in Figure 6, a longitudinal axis of the body 128 is substantially aligned with a longitudinal axis of the filtering portion 140.

In the illustrated embodiment, the body 128 is formed as a single monolithic piece of material. For example, the body 128 may be formed from a single monolithic piece of material via a suitable casting process, a suitable forging process, a suitable plastic moulding process and/or a suitable machining process. In alternative embodiments (not shown), the body 128 may be formed from a plurality of connected components, and/or may be formed via any suitable process.

In the illustrated embodiment, the body 128 is formed from stainless steel. Advantageously, stainless steel is less susceptible to hydrogen embrittlement relative to some other metals. In alternative embodiments, the body 128 may be formed from any suitable material, such as a metal other than stainless steel (e.g. aluminium or copper), or plastic, for example.

The adaptor 126 is elongate and has a length L and a maximum width W transverse to the length L. The length L may be in the range of 30mm to 70mm, optionally 40mm to 60mm, for example approximately 47mm. The maximum width W may be in the range of 15mm to 35mm, optionally 20mm to 30mm, for example approximately 26mm.

In the illustrated embodiment, an external surface 141 of the body 128 adjacent the inlet 130 includes male screw threads for engaging female screw threads of an upstream fuel line (not shown), to enable the inlet 130 to be coupled to said fuel line. In alternative embodiments (not shown), the inlet 130 may be couplable to the upstream fuel line by any suitable means.

Figures 7 and 8 show a fuel supply line 160 for supplying fuel to the adaptor 126. The fuel supply line 160 may form part of the fuel rail assembly 118. The fuel supply line 160 includes a fuel orifice 164. The fuel rail assembly 118 includes a releasable coupling arrangement 162 for releasably coupling the fuel supply line 160 to the adaptor 126. The fuel supply line 160 is releasably coupled to the adaptor 126 via the releasable coupling arrangement 162 such that the fuel orifice 164 is in fluid communication (e.g. sealed fluid communication) with the inlet 130 for supplying fuel from the fuel orifice 164 to the fuel supply passage 122 via the inlet 130.

The releasable coupling arrangement 162 includes a plurality of first locking members 166 on the adaptor 126, and a plurality of corresponding second locking members 168 on the fuel supply line 160. Each corresponding pair of first and second locking members 166, 168 are arranged to engage so as to releasably couple the fuel supply line 160 to the adaptor 126.

In alternative embodiments (not shown), the releasable coupling arrangement 162 may include a single first locking member 166 on the adaptor 126, and a single second locking member 168 on the fuel supply line 160.

The releasable coupling arrangement 162 enables the fuel supply line 160 to be rapidly and securely coupled to the adaptor 126. This is particularly beneficial for when the fuel supply line 160 is to be coupled to the adaptor 126 for a relatively short amount of time (e.g. during hot testing of the engine 100).

Each first locking member 166 is fixed relative to the body 128. Each second locking member 168 is moveable relative to the fuel orifice 164 between unlocked (shown in phantom in Figure 8) and locked positions (shown in solid line in Figure 8). Each first locking member 166 includes a first engaging surface 170, and each second locking member 168 includes a second engaging surface 172. The first and second engaging surfaces 170, 172 are engageable so as to releasably couple the fuel supply line 160 to the body 128 when the second locking member 168 is in the locked position, as shown in Figures 7 and 8. Such a configuration of the second locking member 168 enhances the durability of the releasable coupling arrangement 162, enabling the fuel supply 160 to be coupled to and uncoupled from the adaptor 126 many times before components of the releasable coupling arrangement 162 need to be replaced. In contrast, if corresponding screw threads were used to releasably couple the fuel supply line 160 to the adaptor, the screw threads would wear to the point of needing to be replaced after a relatively small number of coupling-uncoupling cycles.

In the illustrated embodiment, the first locking members 166 are joined to form a circumferential collar, which includes the first engaging surfaces 170. In alternative embodiments (not shown), the first locking members 166 may have any suitable configuration. For example, the first locking members 166 may be joined to form a circumferential recess, which includes the first engaging surfaces 170, or may be provided separately from each other.

In the illustrated embodiment, the body 128 includes the first locking members 166. In alternative embodiments (not shown), each first locking member 166 may be provided as a different component to the body 128.

Each second locking member 168 is pivotable relative to the fuel orifice 164 between the unlocked and locked positions. In particular, each second locking member 168 is pivotable about a respective pivot point 174 connected to the fuel supply line 160. In alternative embodiments (not shown), each second locking member 168 may additionally or alternatively be translationally movable relative to the fuel orifice 164 between the unlocked and locked positions. For example, each second locking member 168 may be translated radially outwards and inwards between unlocked and locked positions respectively.

Each second locking member 168 is biased towards the locked position. In the illustrated embodiment, each second locking member 168 is biased towards the locked position via a biasing member such as torsional springs (not shown). In alternative embodiments, each second locking member 168 may be biased towards the locked position via any suitable means. Alternatively, each second locking member 168 may not be biased towards the locked position.

The releasable coupling arrangement 162 includes a release mechanism 176 configured to selectively move the second locking member 168 between the unlocked and locked positions. In the illustrated embodiment, the release mechanism 176 includes a release member 178 movable between a first position (shown in solid line in Figure 8), in which each second locking member 168 is retained in the locked position, and a second position (shown in phantom in Figure 8) in which each second locking member 168 is moved to the unlocked position. In the illustrated embodiment, the release member 178 is in the form of a cuff surrounding the fuel supply line 160. In alternative embodiments, the release member 178 may have any suitable configuration.

The release member 178 is biased towards the first position. Advantageously, this helps to maintain the coupling between the body 128 and the fuel supply line 160. In the illustrated embodiment, the releasable coupling arrangement 162 includes a biasing member such as a compression spring arranged to bias the release member 178 towards the first position. In alternative embodiments, the release member 178 may biased towards the first position via any suitable means, or may not be biased towards the first position. Additionally or alternatively, in some embodiments, the release member 178 may be selectively retained in the first position by a suitable retainer means.

The releasable coupling arrangement 162 is configured such that, when the longitudinal axis Al of the adaptor 126 and a longitudinal axis A2 of the fuel supply line 160 are substantially aligned, as shown in Figure 8, and the fuel orifice 164 and the inlet 130 are translated together along said respective axes Al, A2, each second locking member 168 moves over the corresponding first locking member 166 such that the first and second engaging surfaces 170, 172 are engageable. Advantageously, this enables rapid coupling of the fuel supply line 160 to the adaptor 126. This is particularly beneficial for hot testing of the engine 100, where an upstream fuel line needs only to be coupled to the engine 100 for a relatively short amount of time.

In the illustrated embodiment, each first locking member 166 includes a first tapered surface 180, and each corresponding second locking member 168 includes a complementary second tapered surface 182. The tapered surfaces 180, 182 are configured such that when the longitudinal axes Al, A2 are substantially aligned, and the fuel orifice 164 and the inlet 130 are translated together along said respective axes Al, A2, abutment of, and relative sliding between, the tapered surfaces 180, 182 causes each second locking member 168 to move over the corresponding first locking member 166 such that the first and second engaging surfaces 170, 172 are engageable.

The first locking members 166 are distributed about the longitudinal axis Al of the body 128. In the illustrated embodiment, the first locking members 166 are connected so as to form a collar. The second locking members 168 are distributed about the longitudinal axis A2 of the fuel supply line 160. In alternative embodiments (not shown), the first and second locking members 166, 168 may have any suitable arrangement.

The fuel rail assembly 118 includes a sealing arrangement 184 between the fuel supply line 160 and the body 128 configured to inhibit fuel exiting the fuel rail assembly 118 via the releasable coupling arrangement 162. In the illustrated embodiment, the seal arrangement 184 includes a seal member 186 in the form of an O-ring between the fuel supply line 160 and the body 128. In alternative embodiments (not shown), the sealing arrangement 184 may include any suitable seal member 186 and/or have any suitable configuration.

In the illustrated embodiment, the seal member 186 is coupled to the fuel supply line 160. The seal member 186 is received in a recess in an external surface of the fuel supply line 160 such that the seal member 186 is coupled to the fuel supply line 160. In alternative embodiments (not shown), the seal member 186 may be coupled to the fuel supply line 160 via any suitable means. Alternatively, the seal member 186 may be coupled to the body 128, or may not be coupled to either the fuel supply line 160 or the body 128.

The fuel orifice 164 is received in the inlet 130. The sealing arrangement 184 is between an external surface 188 of the fuel supply line 160 and a first inner surface 190 of the body 128. In the illustrated embodiment, the external surface 188 and the first internal surface 190 have complementary profiles in planes substantially normal to their respective longitudinal axes Al, A2.

The body 128 includes a second internal surface 192 adjacent the first internal surface 190. The fuel rail assembly 118 is configured such that the fuel supply line 160 is inhibited from contacting the second internal surface 192 when the fuel supply line 160 is coupled to the body 128.

Whereas the fuel supply line 160, which may be referred to as the "first fuel supply line 160", may be used to temporarily supply fuel to the fuel rail 120 (e.g. for hot testing of the engine 100), the second internal surface 192 may be used as a sealing surface for forming a seal between the body 128 and a second upstream fuel supply line used to supply fuel to the fuel rail 120 (e.g. permanently) during normal use of the engine 100. Advantageously, inhibiting the first fuel supply line 160 from contacting the second internal surface 192 when the first fuel supply line 160 is coupled to the body 128, helps to inhibit damage to the second internal surface 192, and thus may help to maintain the efficacy of the second internal surface 192 as a sealing surface.

In the illustrated embodiment, the complementary profiles of the external surface 188 and the first internal surface 190 inhibit relative rotation between the first fuel supply line 160 and the body 128, so as to inhibit the first fuel supply line 160 from contacting the second internal surface 192. In alternative embodiments (not shown), the first fuel supply line 160 may be inhibited from contacting the second internal surface 192 when the first fuel supply line 160 is coupled to the body 128 via any suitable means. In the illustrated embodiment, the second internal surface 192 is axially outboard of the first internal surface 190. In alternative embodiments (not shown), the second internal surface 192 may be axially inboard of the first internal surface 190.

In the illustrated embodiment, the second internal surface 192 is tapered, but in alternative embodiments, may not be.

The fuel rail assembly 118 includes a guide arrangement 194 configured to guide relative movement between the body 128 and the first fuel supply line 160 such that the first and second locking members 166, 168 are engageable so as to releasably couple the first fuel supply line 160 to the body 128.

In the illustrated embodiment, the guide arrangement 194 includes a recess 196 in the first fuel supply line 160 configured to receive a protrusion 198 of the adaptor 126. The recess 196 and the protrusion 198 have complementary profiles.

In the illustrated embodiment, a portion of the body 128 including the inlet 130 forms the protrusion 198. The first fuel supply line 160 includes a peripheral wall 200 surrounding the fuel orifice 164. The recess 196 is defined between the peripheral wall 200 and a wall defining the fuel orifice 164. In alternative embodiments (not shown), the guide arrangement 194 may have any suitable configuration.

As well as guiding relative movement between the body 128 and the first fuel supply line 160, the guide arrangement 194 may also help to inhibit the first fuel supply line 160 from contacting the second internal surface 192 when the first fuel supply line 160 is coupled to the body 128, by inhibiting relative rotation between the first fuel supply line 160 and the body 128.

In alternative embodiments (not shown), the inlet 130 may be received in the fuel orifice 164.

Figure 9 shows an alternative embodiment of a fuel rail assembly 118'. Features shared with the fuel rail assembly 118 are denoted with common reference numerals, and a discussion of which shall not be repeated for brevity. The fuel rail assembly 118' may share any of the features discussed in relation to the fuel rail assembly 118 unless stated otherwise.

In the releasable mounting arrangement 142' of the fuel rail assembly 118', the second engaging portion 146' on the connector 133' of the fuel rail 120' is a male portion, and the first engaging portion 144' on the body 128' is a female portion configured to receive the male portion. The seal arrangement 184' of the fuel rail assembly 118' is configured to inhibit fuel that is flowing from the inlet 130 to the fuel supply passage 122 from contacting the first and second engaging portions 144', 146'. In the illustrated embodiment, the seal arrangement 184' includes a seal member 186' between, and in sealing contact with, the fuel rail 120' and the body 128'. The seal member 186' is arranged to inhibit fuel that is flowing from the inlet 130 to the fuel supply passage 122 from contacting the first and second engaging portions 144', 146'. In the illustrated embodiment, the seal member 186' is an O-ring.

The first and/or second engaging portions 144', 146' may be more likely to introduce contaminants into fuel flowing over them relative to other portions of the adaptor 126'. For example, in embodiments in which the first and second engaging portions 144', 146' include complementary screw threads, said screw threads may introduce burrs into fuel flowing over them. Therefore, inhibiting fuel that is flowing from the inlet 130 to the fuel supply passage 122 from contacting the first and second engaging portions 144', 146', may help to inhibit contaminants entering the fuel.

In the illustrated embodiment, the first engaging portion 144' is a portion of the body 128'. In alternative embodiments (not shown), the first engaging portion 144' may be a portion of a different component of the adaptor 126'. For example, the first engaging portion 144' may be a portion of a fastener, such as a nut, including female screw threads, and the second engaging portion 146' may include male screw threads. The fastener may be configured to clamp the body 128' to the connector 133' when the fastener is tightened to the connector 133'.

In the illustrated embodiment, the fuel filter 132 is mounted to the body 128'. In alternative embodiments (not shown), the fuel filter 132 may additionally or alternatively be clamped between the body 128 and the connector 133' when the body 128 is mounted to the connector 133'.

CLAUSES

Clause 1. A fuel rail assembly for an internal combustion engine, the fuel rail assembly comprising: a fuel rail for supplying fuel to at least one fuel injector; an adaptor for connecting the fuel rail to an upstream fuel line; a first fuel supply line for supplying fuel to the adaptor; and a releasable coupling arrangement for releasably coupling the first fuel supply line to the adaptor; wherein the fuel rail comprises a fuel supply passage by which fuel is supplied to said at least one fuel injector; wherein the adaptor comprises a body including an inlet; wherein the adaptor is mounted to the fuel rail such that the inlet is in fluid communication with the fuel supply passage; wherein the first fuel supply line comprises a fuel orifice; wherein the first fuel supply line is releasably coupled to the adaptor via the releasable coupling arrangement such that the fuel orifice is in fluid communication with the inlet for supplying fuel from the fuel orifice to the fuel supply passage via the inlet.

Clause 2. The fuel rail assembly of clause 1, wherein the releasable coupling arrangement comprises a first locking member on the adaptor and a second locking member on the first fuel supply line, and wherein the first and second locking members are arranged to engage so as to releasably couple the first fuel supply line to the body.

Clause 3. The fuel rail assembly of clause 2, wherein the first locking member is fixed relative to the body, wherein the second locking member is moveable relative to the fuel orifice between unlocked and locked positions, wherein the first locking member comprises a first engaging surface, wherein the second locking member comprises a second engaging surface, and wherein the first and second engaging surfaces are engageable so as to releasably couple the fuel line to the body when the second locking member is in the locked position.

Clause 4. The fuel rail assembly of clause 3, wherein the second locking member is pivotable relative to the fuel orifice between the unlocked and locked positions.

Clause 5. The fuel rail assembly of clauses 3 or 4, wherein the releasable coupling arrangement comprises a release mechanism configured to selectively move the second locking member between the unlocked and locked positions.

Clause 6. The fuel rail assembly of clause 5, wherein the release mechanism comprises a release member movable between a first position, in which the second locking member is retained in the locked position, and a second position in which the second locking member is moved to the unlocked position.

Clause 7. The fuel rail assembly of clause 6, wherein the release member is biased towards and/or selectively retained in the first position. Clause 8. The fuel rail assembly of any one of clauses 3 to 7, wherein the releasable coupling arrangement is configured such that, when respective axes of the adaptor and the fuel line are substantially aligned, and the fuel orifice and the inlet are translated together along said respective axes, the second locking member moves over the first locking member such that the first and second engaging surfaces are engageable.

Clause 9. The fuel rail assembly of any one of clauses 2 to 8, wherein the releasable coupling arrangement comprises a plurality of the first locking members and a corresponding plurality of the second locking members.

Clause 10. The fuel rail assembly of clause 9, wherein the first locking members are distributed about a longitudinal axis of the body, and wherein the second locking members are distributed about a longitudinal axis of the first fuel supply line.

Clause 11. The fuel rail assembly of any one of clauses 2 to 10, further comprising a guide arrangement configured to guide relative movement between the body and the first fuel supply line such that the first and second locking members are engageable so as to releasably couple the fuel line to the body

Clause 12. The fuel rail assembly of clause 11, wherein the guide arrangement comprises a recess in the first fuel supply line configured to receive a protrusion of the adaptor, the recess and the protrusion having complementary profiles.

Clause 13. The fuel rail assembly of any one of clauses 1 to 12, further comprising a sealing arrangement between the first fuel supply line and the body configured to inhibit fuel exiting the fuel rail assembly via the releasable coupling arrangement.

Clause 14. The fuel rail assembly of clause 13, wherein the seal arrangement comprises a seal member, such as an O-ring.

Clause 15. The fuel rail assembly of clause 14, wherein the seal member is coupled to the fuel line.

Clause 16. The fuel rail assembly of any one of clauses 13 to 15, wherein the fuel orifice is received in the inlet, and the sealing arrangement is between an external surface of the first fuel supply line and a first internal surface of the body. Clause 17. The fuel rail assembly of clause 16, wherein the body comprises a second internal surface for forming a seal between the body and a second fuel supply line for supplying fuel to the fuel rail during normal use of the engine, wherein the second internal surface is adjacent the first internal surface, and wherein the fuel rail assembly is configured such that the first fuel supply line is inhibited from contacting the second internal surface when the first fuel supply line is coupled to the body.

Clause 18. The fuel rail assembly of clauses 11 or 12, and clause 17, wherein the guide arrangement is configured to inhibit the first fuel supply line from contacting the second internal surface.

Clause 19. The fuel rail assembly of clauses 17 or 18, wherein the second internal surface is axially outboard of the first internal surface and/or is tapered.

Clause 20. A fuel rail assembly for an internal combustion engine, the fuel rail assembly comprising: a fuel rail for supplying fuel to at least one fuel injector; and an adaptor for connecting the fuel rail to an upstream fuel line; wherein the fuel rail comprises a fuel supply passage by which fuel is supplied to said at least one fuel injector; wherein the adaptor comprises a body including an inlet, wherein the inlet is couplable to said upstream fuel line; wherein the adaptor is mounted to the fuel rail such that the inlet is in fluid communication with the fuel supply passage; wherein the adaptor further comprises a fuel filter for filtering fuel flowing from the inlet to the fuel supply passage; and wherein the fuel filter is housed at least partially within the body.

Clause 21. The fuel rail assembly of clause 20, wherein the fuel filter is mounted to the body.

Clause 22. The fuel rail assembly of clause 21, where the fuel filter is releasably mounted to the body.

Clause 23. The fuel rail assembly of clause 22, wherein the fuel filter is releasably mounted to the body via a releasable mounting arrangement including complementary screw threads on the body and the fuel filter. Clause 24. The fuel rail assembly of any one of clauses 21 to 23, wherein the body is configured such that the fuel filter is receivable within the body via the inlet for mounting the fuel filter to the body.

Clause 25. The fuel rail assembly of any one of clauses 21 to 24, wherein the fuel filter is elongate and comprises opposing first and second longitudinal ends, and wherein the first longitudinal end is mounted to the body.

Clause 26. The fuel rail assembly of clause 25, wherein the second longitudinal end is a free end.

Clause 27. The fuel rail assembly of any one of clauses 21 to 26, wherein the body comprises an outlet arranged such that fuel flows from the inlet to the outlet and then to the fuel supply passage, in use, and wherein the fuel filter is mounted to the outlet.

Clause 28. The fuel rail assembly of clause 27 , wherein fuel flows from the inlet to the fuel filter, then to the outlet and then to the fuel supply passage, in use.

Clause 29. The fuel rail assembly of any one of clauses 20 to 28, wherein the fuel filter comprises an elongate filtering portion configured to filter fuel flowing from the inlet to the fuel passage, in use.

Clause 30. The fuel rail assembly of clause 29, wherein the body is elongate, and wherein a longitudinal axis of the body is substantially aligned with a longitudinal axis of the filtering portion.

Clause 31. The fuel rail assembly of any one of clauses 20 to 30, wherein a portion of the fuel filter is located within the fuel supply passage.

Clause 32. The fuel rail assembly of any one of clauses 20 to 31, wherein the adaptor comprises a sealing arrangement between the fuel filter and the body configured to inhibit fuel flowing from the inlet to the fuel supply passage bypassing the fuel filter.

Clause 33. The fuel rail assembly of clause 32, wherein the sealing arrangement comprises a seal member, such as an O-ring, and/or a sealant, between the body and the fuel filter. Clause 34. The fuel rail assembly of any one of clauses 20 to 33, wherein the fuel filter is wholly housed within the body.

Clause 35. The fuel rail assembly of any one of clauses 20 to 34, further comprising a releasable mounting arrangement, wherein the body is releasably mounted to the fuel rail via the releasable mounting arrangement.

Clause 36. The fuel rail assembly of clause 35, wherein the fuel rail assembly further comprises a sealing arrangement between the body and the fuel rail configured to inhibit fuel exiting the fuel rail assembly via the releasable mounting arrangement.

Clause 37. The fuel rail assembly of clauses 35 or 36, wherein the releasable mounting arrangement comprises a first engaging portion of the body and a second engaging portion of the fuel rail, and wherein engagement of the first and second engaging portions with each other releasably mounts the body to the fuel rail.

Clause 38. The fuel rail assembly of clause 37, wherein the first and second engaging portions comprise complementary screw threads.

Clause 39. The fuel rail assembly of clause 38, wherein a profile of the adaptor in a plane normal to a screw axis of the body has a polygonal shape for engagement with a torque application tool such as a wrench or spanner.

Clause 40. The fuel rail assembly of clause 39, wherein the body comprises said profile.

Clause 41. The fuel rail assembly of any one of clauses 37 to 40, wherein the first engaging portion on the body is a male portion, and the second engaging portion on the fuel rail is a female portion configured to receive the male portion, or wherein the second engaging portion on the fuel rail is a male portion, and the first engaging portion on the body is a female portion configured to receive the male portion.

Clause 42. The fuel rail assembly of any one of clauses 20 to 41, wherein the body is formed as a single monolithic piece of material.

Clause 43. The fuel rail assembly of clause 42, wherein the body is formed from a metal material such as steel, e.g. stainless steel. Clause 44. The fuel rail assembly of any one of clauses 20 to 43, wherein the adaptor extends from the fuel supply passage such that a longitudinal axis of the adaptor is at a non-zero angle to a longitudinal axis of the fuel supply passage.

Clause 45. The fuel rail assembly of clause 44, wherein the non-zero angle is in the range of 45 to 90 degrees.

Clause 46. The fuel rail assembly of clause 45, wherein the longitudinal axis of the adaptor is substantially perpendicular to the longitudinal axis of the fuel supply passage.

Clause 47. The fuel rail assembly of any one of clauses 20 to 46, wherein the fuel filter is a gaseous fuel filter.

Clause 48 The fuel rail assembly of clause 47, wherein the fuel filter is a hydrogen fuel filter.

Clause 49. The fuel rail assembly of any one of clauses 20 to 48, wherein the adaptor is elongate and has a length and a maximum width transverse to the length, wherein the length is in the range of 30mm to 70mm.

Clause 50. The fuel rail assembly of clause 49, wherein the length is in the range of 40mm to 60mm.

Clause 51. The fuel rail assembly of clause 50, wherein the length is approximately 47mm.

Clause 52. The fuel rail assembly of any one of clauses 49 to 51, wherein the maximum width is in the range of 15mm to 35mm.

Clause 53. The fuel rail assembly of clause 52, wherein the maximum width is in the range of 20mm to 30mm.

Clause 54. The fuel rail assembly of clause 53, wherein the maximum width is approximately 26mm.

Clause 55. An internal combustion engine comprising the fuel rail assembly of any one of clauses 1 to 54. Clause 56. The internal combustion engine of clause 55, wherein the internal combustion engine is a gaseous fuel internal combustion engine, e.g. a hydrogen fuel internal combustion engine.

Clause 57. A method of releasably coupling a fuel supply line to a fuel rail of an internal combustion engine, wherein the fuel rail is for supplying fuel to at least one fuel injector, and wherein the fuel rail comprises a fuel supply passage by which fuel is supplied to said at least one fuel injector, wherein the method comprises the steps of: providing an adaptor for connecting the fuel rail to an upstream fuel line, the adaptor comprising a body including an inlet; mounting the adaptor to the fuel rail such that the inlet is in fluid communication with the fuel passage; providing a fuel supply line for supplying fuel to the adaptor, the fuel supply line comprising a fuel orifice; and releasably coupling the fuel supply line to the adaptor via a releasable coupling arrangement such that the fuel orifice is in fluid communication with the inlet for supplying fuel from the fuel orifice to the fuel supply passage via the inlet.

Clause 58. The method of clause 57, wherein the releasable coupling arrangement comprises a first locking member on the adaptor and a second locking member on the fuel line, the first and second locking members arranged to engage so as to releasably couple the fuel line to the body.

Claims

1. A fuel rail assembly for an internal combustion engine, the fuel rail assembly comprising: a fuel rail for supplying fuel to at least one fuel injector; an adaptor for connecting the fuel rail to an upstream fuel line; a first fuel supply line for supplying fuel to the adaptor; and a releasable coupling arrangement for releasably coupling the first fuel supply line to the adaptor; wherein the fuel rail comprises a fuel supply passage by which fuel is supplied to said at least one fuel injector; wherein the adaptor comprises a body including an inlet; wherein the adaptor is mounted to the fuel rail such that the inlet is in fluid communication with the fuel supply passage; wherein the first fuel supply line comprises a fuel orifice; wherein the first fuel supply line is releasably coupled to the adaptor via the releasable coupling arrangement such that the fuel orifice is in fluid communication with the inlet for supplying fuel from the fuel orifice to the fuel supply passage via the inlet.

2. The fuel rail assembly of claim 1, wherein the releasable coupling arrangement comprises a first locking member on the adaptor and a second locking member on the first fuel supply line, and wherein the first and second locking members are arranged to engage so as to releasably couple the first fuel supply line to the body.

3. The fuel rail assembly of claim 2, wherein the first locking member is fixed relative to the body, wherein the second locking member is moveable relative to the fuel orifice between unlocked and locked positions, wherein the first locking member comprises a first engaging surface, wherein the second locking member comprises a second engaging surface, and wherein the first and second engaging surfaces are engageable so as to releasably couple the fuel line to the body when the second locking member is in the locked position; optionally, wherein the second locking member is pivotable relative to the fuel orifice between the unlocked and locked positions.

4. The fuel rail assembly of claim 3, wherein the releasable coupling arrangement comprises a release mechanism configured to selectively move the second locking member between the unlocked and locked positions; optionally, wherein the release mechanism comprises a release member movable between a first position, in which the second locking member is retained in the locked position, and a second position in which the second locking member is moved to the unlocked position; optionally, wherein the release member is biased towards and/or selectively retained in the first position.

5. The fuel rail assembly of claims 3 or 4, wherein the releasable coupling arrangement is configured such that, when respective axes of the adaptor and the fuel line are substantially aligned, and the fuel orifice and the inlet are translated together along said respective axes, the second locking member moves over the first locking member such that the first and second engaging surfaces are engageable.

6. The fuel rail assembly of any one of claims 2 to 5, wherein the releasable coupling arrangement comprises a plurality of the first locking members and a corresponding plurality of the second locking members; optionally, wherein the first locking members are distributed about a longitudinal axis of the body, and wherein the second locking members are distributed about a longitudinal axis of the first fuel supply line.

7. The fuel rail assembly of any one of claims 2 to 6, further comprising a guide arrangement configured to guide relative movement between the body and the first fuel supply line such that the first and second locking members are engageable so as to releasably couple the fuel line to the body; optionally, wherein the guide arrangement comprises a recess in the first fuel supply line configured to receive a protrusion of the adaptor, the recess and the protrusion having complementary profiles.

8. The fuel rail assembly of any preceding claim, further comprising a sealing arrangement between the first fuel supply line and the body configured to inhibit fuel exiting the fuel rail assembly via the releasable coupling arrangement; optionally, wherein the seal arrangement comprises a seal member, such as an O-ring; optionally, wherein the seal member is coupled to the fuel line.

9. The fuel rail assembly of claim 8, wherein the fuel orifice is received in the inlet, and the sealing arrangement is between an external surface of the first fuel supply line and a first internal surface of the body.

10. The fuel rail assembly of claim 9, wherein the body comprises a second internal surface for forming a seal between the body and a second fuel supply line for supplying fuel to the fuel rail during normal use of the engine, wherein the second internal surface is adjacent the first internal surface, and wherein the fuel rail assembly is configured such that the first fuel supply line is inhibited from contacting the second internal surface when the first fuel supply line is coupled to the body.

11. The fuel rail assembly of claims 7 and 10, wherein the guide arrangement is configured to inhibit the first fuel supply line from contacting the second internal surface.

12. The fuel rail assembly of claims 10 or 11, wherein the second internal surface is axially outboard of the first internal surface and/or is tapered.

13. A fuel rail assembly for an internal combustion engine, the fuel rail assembly comprising: a fuel rail for supplying fuel to at least one fuel injector; and an adaptor for connecting the fuel rail to an upstream fuel line; wherein the fuel rail comprises a fuel supply passage by which fuel is supplied to said at least one fuel injector; wherein the adaptor comprises a body including an inlet, wherein the inlet is couplable to said upstream fuel line; wherein the adaptor is mounted to the fuel rail such that the inlet is in fluid communication with the fuel supply passage; wherein the adaptor further comprises a fuel filter for filtering fuel flowing from the inlet to the fuel supply passage; and wherein the fuel filter is housed at least partially within the body.

14. The fuel rail assembly of claim 13, wherein the fuel filter is mounted to the body; optionally, where the fuel filter is releasably mounted to the body.

15. The fuel rail assembly of claim 14, wherein the fuel filter is elongate and comprises opposing first and second longitudinal ends, and wherein the first longitudinal end is mounted to the body; optionally, wherein the second longitudinal end is a free end.

16. The fuel rail assembly of claims 14 or 15, wherein the body comprises an outlet arranged such that fuel flows from the inlet to the outlet and then to the fuel supply passage, in use, and wherein the fuel filter is mounted to the outlet; optionally, wherein fuel flows from the inlet to the fuel filter, then to the outlet and then to the fuel supply passage, in use.

17. The fuel rail assembly of any one of claims 13 to 16, wherein the fuel filter comprises an elongate filtering portion configured to filter fuel flowing from the inlet to the fuel passage, in use; optionally, wherein the body is elongate, and wherein a longitudinal axis of the body is substantially aligned with a longitudinal axis of the filtering portion.

18. The fuel rail assembly of any one of claims 13 to 17, wherein a portion of the fuel filter is located within the fuel supply passage.

19. The fuel rail assembly of any one of claims 13 to 18, wherein the adaptor comprises a sealing arrangement between the fuel filter and the body configured to inhibit fuel flowing from the inlet to the fuel supply passage bypassing the fuel filter; optionally, wherein the sealing arrangement comprises a seal member, such as an O-ring, and/or a sealant, between the body and the fuel filter.

20. The fuel rail assembly of any one of claims 13 to 19, wherein the fuel filter is wholly housed within the body.

21. The fuel rail assembly of any one of claims 13 to 20, further comprising a releasable mounting arrangement, wherein the body is releasably mounted to the fuel rail via the releasable mounting arrangement; optionally, wherein the fuel rail assembly further comprises a sealing arrangement between the body and the fuel rail configured to inhibit fuel exiting the fuel rail assembly via the releasable mounting arrangement.

22. The fuel rail assembly of claim 21, wherein the releasable mounting arrangement comprises a first engaging portion of the body and a second engaging portion of the fuel rail, and wherein engagement of the first and second engaging portions with each other releasably mounts the body to the fuel rail; optionally, wherein the first and second engaging portions comprise complementary screw threads; optionally, wherein a profile of the adaptor in a plane normal to a screw axis of the body has a polygonal shape for engagement with a torque application tool such as a wrench or spanner; optionally, wherein the body comprises said profile.

23. The fuel rail assembly of claim 22, wherein the first engaging portion on the body is a male portion, and the second engaging portion on the fuel rail is a female portion configured to receive the male portion, or wherein the second engaging portion on the fuel rail is a male portion, and the first engaging portion on the body is a female portion configured to receive the male portion.

24. The fuel rail assembly of any one of claims 13 to 23, wherein the body is formed as a single monolithic piece of material; optionally, wherein the body is formed from a metal material such as steel, e.g. stainless steel.

25. The fuel rail assembly of any one of claims 13 to 24, wherein the adaptor extends from the fuel supply passage such that a longitudinal axis of the adaptor is at a non-zero angle to a longitudinal axis of the fuel supply passage; optionally, wherein the non-zero angle is in the range of 45 to 90 degrees, for example, wherein the longitudinal axis of the adaptor is substantially perpendicular to the longitudinal axis of the fuel supply passage.

26. The fuel rail assembly of any one of claims 13 to 25, wherein the fuel filter is a gaseous fuel filter; optionally, wherein the fuel filter is a hydrogen fuel filter.

27. The fuel rail assembly of any one of claims 13 to 26, wherein the adaptor is elongate and has a length and a maximum width transverse to the length, wherein the length is in the range of 30mm to 70mm, optionally 40mm to 60mm, for example approximately 47mm, and/or wherein the maximum width is in the range of 15mm to 35mm, optionally 20mm to 30mm, for example approximately 26mm.

28. An internal combustion engine comprising the fuel rail assembly of any preceding claim; optionally, wherein the internal combustion engine is a gaseous fuel internal combustion engine, e.g. a hydrogen fuel internal combustion engine.

29. A method of releasably coupling a fuel supply line to a fuel rail of an internal combustion engine, wherein the fuel rail is for supplying fuel to at least one fuel injector, and wherein the fuel rail comprises a fuel supply passage by which fuel is supplied to said at least one fuel injector, wherein the method comprises the steps of: providing an adaptor for connecting the fuel rail to an upstream fuel line, the adaptor comprising a body including an inlet; mounting the adaptor to the fuel rail such that the inlet is in fluid communication with the fuel passage; providing a fuel supply line for supplying fuel to the adaptor, the fuel supply line comprising a fuel orifice; and releasably coupling the fuel supply line to the adaptor via a releasable coupling arrangement such that the fuel orifice is in fluid communication with the inlet for supplying fuel from the fuel orifice to the fuel supply passage via the inlet.