A refuelling system

Abstract

A refuelling system for a working machine, the refuelling system comprising: a refuelling circuit configured to be coupled to an external supply of gaseous fuel, wherein the refuelling circuit comprises: a machine storage device configured to store a gaseous fuel under pressure on the working machine; and a gaseous fuel compressor configured to be powered by a machine power source of the working machine; wherein the refuelling circuit is configured to provide gaseous fuel to the machine storage device from the external supply of gaseous fuel; and wherein the refuelling circuit is configured to direct gaseous fuel through the gaseous fuel compressor when it is determined that a flow of gaseous fuel from the external supply of gaseous fuel to the machine storage device is, or would be, below a threshold.

Description

[0001] A Refuelling System

[0002] FIELD

[0003] The present teachings relate to a refuelling system, a working machine, and a method of refuelling a working machine.

[0004] BACKGROUND

[0005] Off-highway vehicles / working machines are typically those used in construction industries (e.g. backhoe loaders, slew excavators, telescopic handlers, forklifts, skid-steer loaders, dump trucks, bulldozers, graders), agricultural industries (e.g. tractors, wheeled loading shovels, telescopic handlers, self-propelled harvesters and sprayers), quarrying (e.g. excavators, wheeled loading shovels, aggregate crushing equipment), and forestry (e.g. timber harvesters, feller bunchers). Many working machines have a primary function of moving material using either a lifting arm (e.g. a pivoting boom) or a working arm (e.g. an excavator arm) and may be referred to as working machines.

[0006] Conventionally, working machines of the type referred to above are generally powered by diesel internal combustion engines. However, there is a general need to reduce vehicle emissions in the face of global warming leading to working machine OEMs considering alternative prime movers. Proposed alternatives include battery, hydrogen fuel cells, hydrogen internal combustion engines and various hybrid options, etc. Many of the proposed alternatives use gaseous fuel to power the working machine.

[0007] It is necessary that gaseous fuel is stored on a working machine under high pressure, in order to provide sufficient energy to power the machine for an extended period between refuelling operations. This makes refuelling processes more complex, especially where such machines are typically operating in remote locations where electrical grid power and centralised refuelling infrastructure may not be readily available. As a result fuel may need to be provided by mobile storage devices -e.g. bowsers. Typically, such refuelling processes are inefficient and require bulky equipment.

[0008] The present teachings seek to overcome or at least mitigate one or more problems associated with the prior art. SUMMARY

[0009] A first aspect of the teachings provides a refuelling system for a working machine, the refuelling system comprising: a refuelling circuit configured to be coupled to an external supply of gaseous fuel, wherein the refuelling circuit comprises: a machine storage device configured to store a gaseous fuel under pressure on the working machine; and a gaseous fuel compressor configured to be powered by a machine power source of the working machine; wherein the refuelling circuit is configured to provide gaseous fuel to the machine storage device from the external supply of gaseous fuel; and wherein the refuelling circuit is configured to direct gaseous fuel through the gaseous fuel compressor when it is determined that a flow of gaseous fuel from the external supply of gaseous fuel to the machine storage device is, or would be, below a threshold.

[0010] Advantageously, the refuelling system increases the utilisation of gaseous fuel during the refuelling process. During refuelling, if the pressure of the external supply of gaseous fuel is greater than the pressure of the machine storage device, gaseous fuel will flow from the external supply of gaseous fuel to the machine storage device to refuel the machine storage device. Once the pressure of the external supply of gaseous fuel is equal to or less than the pressure of the machine storage device, gaseous fuel will no longer flow from the external supply of gaseous fuel to the machine storage device, and the remaining fuel in the external supply of gaseous fuel cannot be utilised by the working machine.

[0011] Providing a gaseous fuel compressor in the refuelling circuit raises the pressure of the gaseous fuel such that the gaseous fuel flows from the external supply of gaseous fuel to the machine storage device, and the efficiency of the refuelling process is increased. Additionally, the gaseous fuel compressor enables low pressure external supply of gaseous fuels to be used for refuelling the working machine. The inclusion of the gaseous fuel compressor on the working machine negates the need for external gaseous fuel compressors on site, which are expensive and bulky. The refuelling circuit may be configured to selectively direct gaseous fuel through the gaseous fuel compressor when it is determined that a flow of gaseous fuel from the external supply of gaseous fuel to the machine storage device is, or would be, below a threshold

[0012] The refuelling system may be configured to automatically direct gaseous fuel through the gaseous fuel compressor when it is determined that a flow of gaseous fuel to the machine storage device is, or would be, below the threshold.

[0013] Advantageously, the automatic directing of the gaseous fuel through the gaseous fuel compressor helps to ensure refuelling takes place, without relying on an input from the operator or operator judgement.

[0014] The refuelling system may be configured to produce an indication to an operator that the flow of gaseous fuel from the external supply of gaseous fuel to the machine storage device is, or would be, below the threshold.

[0015] Advantageously, the operator can direct gaseous fuel through the gaseous fuel compressor based on the indication, thereby manually increasing the efficiency of the refuelling process.

[0016] The refuelling circuit may comprise a first fuel circuit for refuelling under the pressure of the gaseous fuel in the external supply and a second fuel circuit, and the gaseous fuel compressor may be part of the second fuel circuit.

[0017] Advantageously, the provision of first and second fuel circuits enables gaseous fuel to be directed through the gaseous fuel compressor when there is a determined need for an increase in pressure, and through the first circuit when there is no need for an increase in pressure. This increases the efficiency of the refuelling system by only utilising the gaseous fuel compressor when there is a lack of flow of gaseous fuel to the machine storage device.

[0018] The gaseous fuel compressor may be configured to automatically draw gaseous fuel therethrough when the gaseous fuel compressor is powered by the machine power source.

[0019] The machine storage device may be configured to provide gaseous fuel to power a prime mover, for example a gaseous fuel engine, during operation of the working machine. At least a portion of the machine storage device may be configured to be isolated from the machine power source during refuelling.

[0020] Advantageously, isolating the machine storage device optimises the storage capacity of the machine storage device because the machine storage device can be refuelled without using fuel to power the machine power source.

[0021] The refuelling circuit may comprise a gaseous fuel line connected to the gaseous fuel compressor, and the gaseous fuel line may be configured to bypass the machine storage device and supply gaseous fuel to the machine power source from the external supply of gaseous fuel during refuelling.

[0022] Advantageously, powering the gaseous fuel compressor with the external supply of gaseous fuel helps to optimise the storage capacity of the machine storage device because gaseous fuel from the machine storage device does not need to be used as the fuel source. Additionally, using the external supply of gaseous fuel negates the need for additional components, thereby reducing the complexity of the refuelling system.

[0023] The machine storage device may comprise a plurality of machine storage tanks or vessels.

[0024] Advantageously, the provision of a plurality of machine storage tanks or vessels increases the storage capabilities of refuelling system.

[0025] At least one of the plurality of machine storage tanks or vessels may be isolated from the remainder of the machine storage tanks or vessels during refuelling.

[0026] The at least one of the plurality of machine storage tanks or vessels may be configured to power the machine power source during refuelling.

[0027] Advantageously, this arrangement enables the machine storage device to act as a fuel supply for the gaseous fuel compressor, whilst being refuelled by the external supply of gaseous fuel. Additionally, using the external supply of gaseous fuel negates the need for additional components, thereby reducing the complexity of the refuelling system.

[0028] The refuelling system may be configured to determine a first pressure indicative of the external supply of gaseous fuel, and / or a second pressure indicative of the machine storage device. Advantageously, determining the pressures of the external supply of gaseous fuel and the machine storage device determines whether gaseous fuel is flowing from the external gaseous fuel supply to the machine storage device.

[0029] The refuelling system may be configured to direct gaseous fuel to the machine storage device via the gaseous fuel compressor when the refuelling system determines that the first pressure is less than or equal to the second pressure or when the refuelling system determines that the first pressure is less than or equal to the threshold.

[0030] Advantageously, directing gaseous fuel through the gaseous fuel compressor raises the pressure and enables low pressure external supply of gaseous fuels to be used for refuelling the working machine. Using a threshold may negate the need for a separate pressure reading, particularly if the pressure of the machine storage device is known.

[0031] The refuelling system may be configured to produce an indication to the operator indicative of the first and / or second pressures.

[0032] Advantageously, the operator can use the difference between the first and second pressure to determine whether there is a flow of gaseous fuel to the machine storage device, and direct the gaseous fuel through the gaseous fuel compressor based on the indication of the first and second pressure.

[0033] The refuelling system may comprise a sensor arrangement configured to measure a parameter indicative of the flow of gaseous fuel from the external supply of gaseous fuel to the machine storage device.

[0034] Advantageously, different sensors or combinations of sensors can be used to determine whether gaseous fuel is flowing from the external supply of gaseous fuel to the machine storage device.

[0035] The sensor arrangement may comprise at least one of a flow sensor, a pressure sensor, a temperature sensor, an ultrasonic sensor and / or an optical sensor.

[0036] Advantageously, such sensors are relatively simple and low cost, and can each be used to determine whether gaseous fuel is flowing from the external supply of gaseous fuel to the machine storage device. The refuelling system may comprise a controller configured to determine the flow of gaseous fuel from the external supply of gaseous fuel to the machine storage device.

[0037] Advantageously, the use of a controller may allow for a more refined system.

[0038] The gaseous fuel compressor may be a piston pump or a diaphragm pump configured to be coupled to the machine power source.

[0039] Advantageously, such compressors are suitable for use with gaseous fuels, and have the ability to compress gaseous fuel to the required pressure.

[0040] The rated pressure capacity of the machine storage device may be at least 35MPa.

[0041] Advantageously, such pressure have been found to be optimal to power a working machine.

[0042] A second aspect of the present teachings relates to a working machine comprising: a machine power source configured to provide power to components of the working machine; a refuelling circuit configured to be coupled to an external supply of gaseous fuel, wherein the refuelling circuit comprises: a machine storage device configured to store a gaseous fuel under pressure on the working machine; and a gaseous fuel compressor configured to be powered by the machine power source, wherein the gaseous fuel compressor is located on the working machine; wherein the refuelling circuit is configured to provide gaseous fuel to the machine storage device from the external supply of gaseous fuel; and wherein the refuelling circuit is configured to direct gaseous fuel through the gaseous fuel compressor when it is determined that a flow of gaseous fuel from the external supply of gaseous fuel to the machine storage device is, or would be, below a threshold.

[0043] Advantageously, the refuelling system increases the utilisation of gaseous fuel during the refuelling process. During refuelling, if the pressure of the external supply of gaseous fuel is greater than the pressure of the machine storage device, gaseous fuel will flow from the external supply of gaseous fuel to the machine storage device to refuel the machine storage device. Once the pressure of the external supply of gaseous fuel is equal to or less than the pressure of the machine storage device, gaseous fuel will no longer flow from the external supply of gaseous fuel to the machine storage device, and the remaining fuel in the external supply of gaseous fuel cannot be utilised by the working machine.

[0044] Providing a gaseous fuel compressor in the refuelling circuit raises the pressure of the gaseous fuel such that the gaseous fuel flows from the external supply of gaseous fuel to the machine storage device, and the efficiency of the refuelling process is increased. Additionally, the gaseous fuel compressor enables low pressure external supply of gaseous fuels to be used for refuelling the working machine. The inclusion of the gaseous fuel compressor on the working machine negates the need for external gaseous fuel compressors on site, which are expensive and bulky.

[0045] The machine power source may be at least one of a gaseous fuel engine, a battery or a hydrogen fuel cell.

[0046] Advantageously, the refuelling system uses existing components of the working machine to power the gaseous fuel compressor. This reduces the need for bulky and expensive external power sources.

[0047] The working machine may comprise a prime mover, for example a gaseous fuel engine, and the machine storage device may be configured to provide gaseous fuel to power the prime move during operation of the working machine.

[0048] The working machine may be an excavator, a wheeled loader, a telehandler, a backhoe loader, a tractor or a mobile electric generator.

[0049] A third aspect of the present teachings relate to a method of refuelling a working machine comprising a machine power source and a refuelling system, wherein the refuelling system comprises a refuelling circuit, a machine storage device configured to store a gaseous fuel under pressure on the working machine, the method comprising the steps of: coupling an external supply of gaseous fuel to the refuelling circuit; running the machine power source; providing gaseous fuel from the external supply of gaseous fuel to the machine storage device; determining that a flow of gaseous fuel from the external supply of gaseous fuel to the machine storage is, or would be, below a threshold; and powering the gaseous fuel compressor using the machine power source and directing gaseous fuel through the gaseous fuel compressor.

[0050] BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Embodiments will now be described with reference to the accompanying drawings, in which:

[0052] Figure 1 is a side view of a working machine according to an embodiment of the present teachings;

[0053] Figure 2 is schematic view of the working machine of Figure 1 during refuelling;

[0054] Figure 3 is a schematic view of a refuelling system according to the present teachings for refuelling the working machine of Figure 1;

[0055] Figure 4 is a schematic view of an alternative refuelling system according to the present teachings for refuelling the working machine of Figure 1; and

[0056] Figure 5 is an exemplary embodiment of the control logic followed by the refuelling system of Figure 3.

[0057] DETAILED DESCRIPTION OF EMBODIMENT(S)

[0058] Referring firstly to Figure 1, there is shown a working machine 10. The working machine 10 of the described embodiment is a working machine 10 in the form of a telehandler. However, it shall be appreciated that the present disclosure may be applicable to other working machines which comprise a prime mover 11 which is operable using a gaseous fuel, such as a hydrogen powered internal combustion engine 11 or hydrogen fuel cell. By way of example, the working machine 10 may be an excavator, a wheeled loader, a backhoe loader or a tractor. Alternatively, the present disclosure may be applicable to mobile electric generators and the like with gaseous powered prime movers.

[0059] The working machine 10 includes a body 12, an operator cab 13, a working arm (lifting arm in this embodiment) 14 pivotably mounted proximate a first end to the body 12 for pivoting movement about a first generally horizontal axis, and an engine housing, in which a prime mover 11 (shown schematically) is located. The body 12 is located on a ground engaging structure 17 which is in the form of axle mounted front 17 and rear wheels 17. The machine 10 is generally elongate having a principal longitudinal axis. The operator cab 13 is aligned with the longitudinal axis and defines the principal forward facing direction of travel of the working machine 10.

[0060] The lifting arm 14 is configured to carry a load handling implement 15, such as a shovel 15 or forks, at a second end and is configured to allow the load handling implement 15 to pivot relative to the lifting arm 14 about a second generally horizontal axis so that a load may be kept in a constant horizontal or other desired orientation as the lifting arm 14 pivots up and down, as is well known in the art.

[0061] In this embodiment, the prime mover 11 functions as a machine power source 20 configured to provide power to components of the working machine 10 and a refuelling system 22 configured to be coupled with an external supply of gaseous fuel 26, as illustrated in Figure 2. It shall be appreciated that the machine power source 20 may be the prime mover 11, or an alternative machine power source, as will be described in more detail below.

[0062] The prime mover 11 may be in the form of a gaseous fuel engine 11 which is configured to run on a gaseous fuel. The prime mover 11 may be configured to provide motive power to the ground engaging structure 17 and / or at least one hydraulic pump 19. The hydraulic pump 19 may be used to drive hydraulic actuators (not shown) required for the operation of the lifting arm 14 or some other hydraulic service. The hydraulic pump 19 supplies hydraulic fluid via a hydraulic fluid circuit 25.

[0063] The gaseous fuel may be any suitable fuel such as compressed natural gas, hydrogen, biogas, for example, all of which are known in the art. The gas may be one type of gas in isolation (e.g. pure hydrogen) or a blend of two or more gases. The gaseous fuel engine 11 may be an internal combustion engine 11. In preferred embodiments, the engine will be either a port fuel injected or direct injected hydrogen internal combustion engine 11.

[0064] In other embodiments, the powertrain of the working vehicle may comprise a hydrogen fuel cell (not shown) or some other form of gas powered energy conversion device which generates electricity to power one or more electric motors (not shown). The prime mover may be dual fuel (i.e. switchable between different fuel types) in some embodiments, and the machine 10 may be a hybrid machine providing motive power from stored electrical energy and gaseous fuel energy sources. The gaseous fuel engine 11 may be powered exclusively by hydrogen.

[0065] As illustrated schematically in the embodiment of Figure 1, the working machine 10 includes a machine storage device 18. In this embodiment the machine storage device 18 is defined by a plurality of individual tanks or vessels 18a-c in which the gaseous fuel is received and stored for use by the gaseous fuel engine 11. The machine storage tanks 18a-c are high pressure storage tanks, however any suitable device may be used. The machine storage device 18 is mounted to the working machine 10 in any suitable location on the working machine 10, as illustrated schematically in Figure 1. There are three individual tanks 18a-c defining the machine storage device 18 in the embodiment of Figure 1, but there may be more or fewer than this in other embodiments and they may be split between different locations.

[0066] In order for gaseous fuels, such as hydrogen, to provide a useful amount of energy to power the gaseous fuel engine 11, the gaseous fuel is stored under high pressure in the machine storage device 18. This enables a larger amount of hydrogen to be stored in a smaller machine storage device 18, which is useful as a fuel source for working machines 10 where space is limited. The rated pressure capacity of the machine storage device 18 is typically greater than 35MPa.

[0067] The refuelling system 22 includes a coupling device 33 configured to receive a corresponding coupling device 35 of the external supply of gaseous fuel 26. The coupling device 33 of the refuelling circuit 22 may be a high pressure filling nozzle configured to receive a corresponding nozzle 35 of the external supply of gaseous fuel 26, as is known in the art. The coupling device 33 may be located upstream of the machine storage device 18.

[0068] The external supply of gaseous fuel 26 may include one or more storage tanks or vessels 26a-c, or any alternative device may be used. It shall be appreciated that there may be any suitable number of storage tanks 26a-c, for example three storage tanks 26a-c provided. The storage tanks 26a-c typically have a rated pressure of at least 50MPa, sometimes 75MPa. However, the tanks may become depleted through refuelling operations and may contain fuel at less than 30MPa, or less than 20MPa. In other embodiments, the external hydrogen storage may have a maximum rated pressure of less than 30MPa, or less than 20MPa, since such storage may be more readily available in certain locations and / or may be subject to less onerous regulations for transportation or use. The refuelling system 22 according to a first embodiment is illustrated in Figures 2 and 3. The refuelling system 22 includes a refuelling circuit 24 configured to be coupled to the external supply of gaseous fuel 26 such that the external supply of gaseous fuel 26 provides gaseous fuel to the working machine 10 during refuelling, as illustrated in simplified form in Figure 2. The refuelling circuit 24 is configured to provide gaseous fuel to the machine storage device 18 from the external supply of gaseous fuel 26.

[0069] The refuelling system 22 includes the machine storage device 18 configured to store gaseous fuel under pressure on the working machine 10, and a gaseous fuel compressor 28 configured to be powered by the machine power source 20. The refuelling system 22 may further include any one of, or any combination of, a first fuel circuit 30, a second fuel circuit 32, a sensor arrangement 34a, 34b an indicator 37 and / or a controller 23. The refuelling circuit 24 is configured to direct gaseous fuel through the gaseous fuel compressor 28 when it is determined that a flow of gaseous fuel from the external supply of gaseous fuel 26 to the machine storage device 18 is, or would be, below a threshold.

[0070] The gaseous fuel compressor 28 may be a suitable piston pump (as depicted in Figure 3), diaphragm pump or any other suitable pump, as is known in the art.

[0071] During refuelling, if the pressure of the external supply of gaseous fuel 26 is greater than the pressure of the machine storage device 18, gaseous fuel will flow from the external supply of gaseous fuel 26 to the machine storage device 18 to refuel the machine storage device 18 without requiring compression. Once the pressure of the external supply of gaseous fuel 26 is equal to or less than the pressure of the machine storage device 18, gaseous fuel will no longer flow from the external supply of gaseous fuel 26 to the machine storage device 18, and the remaining fuel in the external supply of gaseous fuel 26 cannot be utilised by the working machine 10. This reduces the efficiency of the refuelling system 22.

[0072] The first fuel circuit, illustrated in Figure 3, is for refuelling under the pressure of the gaseous fuel in the external supply of gaseous fuel 26. The first fuel circuit 30 is used to transfer gaseous fuel from the external supply of gaseous fuel 26 to the machine storage device 18 when the pressure of the external supply of gaseous fuel 26 is greater than the pressure of the machine storage device 18.

[0073] When the pressure of the external supply of gaseous fuel 26 approaches the pressure of the machine storage device 18, the flow rate of gaseous fuel through the refuelling circuit 24 may reduce to an inefficient level for refuelling. It may therefore be advantageous to set the threshold such that gaseous fuel flows through the gaseous fuel compressor 28 when the pressure of the external supply of gaseous fuel decreases to a pressure greater than the pressure of the machine storage device 18.

[0074] The first fuel circuit 30 includes a valve 38, for example a check valve 38. The valve 38 is included in the refuelling circuit 24 to prevent the backflow of gaseous fuel from the machine storage device 18 to the external supply of gaseous fuel 26 when the pressure of the machine storage device 18 is greater than or equal to the pressure of the external supply of gaseous fuel 26.

[0075] The second fuel circuit 32 is used to transfer gaseous fuel from the external supply of gaseous fuel 26 to the machine storage device 18 when the pressure of the external supply of gaseous fuel 26 is less than, or approaches, the pressure of the machine storage device 18. The second fuel circuit 32 is at least partially separate to the first fuel circuit 30, however the first and second fuel circuits 30, 32 may include common sections, for example when the first and second fuel circuits 30, 32 re-join. The gaseous fuel compressor 28 is connected to the second fuel circuit 32. The refuelling system 22 is configured to direct the gaseous fuel through the second circuit 32 when it is determined that the flow of gaseous fuel from the external supply of gaseous fuel 26 to the machine storage device 18 is, or would be, below the threshold.

[0076] Providing a gaseous fuel compressor 28 in the refuelling circuit 24 raises the pressure of the gaseous fuel such that the gaseous fuel flows from the external supply of gaseous fuel 26 to the machine storage device 18 even when the pressure of the external supply of gaseous fuel 26 is less than or equal to the pressure of the machine storage device 18. This helps to improve the efficiency of the refuelling process. Additionally, the gaseous fuel compressor 28 enables low pressure external supply of gaseous fuels to be used for refuelling the working machine 10. The inclusion of the gaseous fuel compressor 28 on the working machine 10 negates the need for external gaseous fuel compressors on a worksite with their own power source, which are expensive and bulky. The gaseous fuel compressor 28 may be configured to raise the pressure of the gaseous fuel to a pressure greater than the pressure of the machine storage device 18. The gaseous fuel compressor 28 is associated with the working machine 10. The gaseous fuel compressor 28 may be located on, or mounted to, the working machine 10

[0077] In the embodiment of Figure 3, the gaseous fuel compressor 28 is driven by a hydraulic motor 21, and the gaseous fuel compressor 28 is a hydrogen compressor 28. In this embodiment, the gaseous fuel compressor 28 and the hydraulic motor 21 may be permanently connected to the hydraulic fluid circuit 25 of the working machine 10. Put another way, the gaseous fuel compressor 28 and hydraulic motor 21 may be integral components of the working machine 10 which are installed at the time of the working machine's manufacture, or are subsequently retrofitted to the working machine 10.

[0078] The hydraulic motor 21 is supplied with hydraulic fluid from an existing hydraulic fluid circuit 25 of the working machine 10. The hydraulic fluid circuit 25 may additionally be used for supplying hydraulic fluid for other machine functions such as hydraulic actuators for the lifting arm, machine steering etc.

[0079] The hydraulic fluid circuit 25 is powered by the hydraulic pump 19. The hydraulic fluid circuit 25 powered by the hydraulic pump 19 is connected to the gaseous fuel compressor 28 to supply hydraulic fluid to the gaseous fuel compressor 28. The hydraulic fluid circuit 25 includes a valve 31, for example a solenoid controlled spool valve, to selectively isolate the gaseous fuel compressor 28 from the hydraulic fluid circuit 25 when the gaseous fuel compressor 28 is not being used to increase the pressure of gaseous fuel in the refuelling circuit 24. As such, hydraulic fluid is not supplied to the gaseous fuel compressor 28 and gaseous fuel is not drawn into the gaseous fuel compressor 28 when not required.

[0080] The hydraulic pump 19 is in turn powered by the gaseous fuel engine 11, for example the hydrogen internal combustion engine 11 illustrated in Figure 3. As such, the hydrogen internal combustion engine 11 of the working machine 10 acts as the machine power source 20 and powers the gaseous fuel compressor 28. This arrangement has the advantage of utilising the existing hydraulic systems of the working machine 10, such as the hydraulic fluid circuit 25 and the hydraulic pump 19, to provide power to the hydraulic motor 21 driving the gaseous fuel compressor 28 from the machine power source 20.

[0081] In order to provide the gaseous fuel to the machine power source 20 to power the gaseous fuel compressor 28, a supply of gaseous fuel from the machine storage device 18 may be used, as illustrated in Figure 3. The use of the machine storage device 18 as the gaseous fuel supply reduces the complexity of the refuelling system 22.

[0082] In embodiments where the machine storage device 18 is used to fuel the gaseous fuel compressor 28, at least one of the machine storage tanks 18a-c is used for refuelling whilst the remainder of the machine storage tanks 18a-c are refuelled. By way of example, the machine storage device 18a may be used to provide power to operate the gaseous fuel compressor 28 (via the gaseous fuel engine 11 and hydraulic fluid circuit 25), and the machine storage devices 18b, 18c may be refuelled. It shall be appreciated that in alternative embodiments with alternative numbers of machine storage tanks 18a-c, any suitable number of machine storage tanks 18a-c may be used for refuelling / providing fuel to operate the gaseous fuel compressor 28.

[0083] In certain jurisdictions regulations and / or safety standards stipulate that during refuelling, a storage tank 18a-c may not be simultaneously used as a fuel source, whilst at the same time being refuelled. The refuelling system 22 therefore includes an isolation function in this embodiment to comply with such regulations / standards. The isolation function is configured to at least partially isolate the machine storage tank 18a from the remainder of the machine storage tanks 18b, 18c. This enables the machine storage device 18a to act as a gaseous fuel supply for the gaseous fuel compressor 28, whilst the remainder of the machine storage tanks 18b, 18c are being refuelled by the external supply of gaseous fuel 26 at the same time.

[0084] The refuelling circuit 24 includes at least one valve 36, 39, for example an isolation valve or a shut-off valve, to at least partially isolate the machine storage tank 18a from the remainder of the machine storage tanks 18b, 18c. The first isolation valve 36 is configured to isolate the machine storage tank 18a from the external supply of gaseous fuel 26. The second isolation valve 39 is configured to isolate the machine storage tanks 18b, 18c from the gaseous fuel engine 11. Accordingly, the machine storage tank 18a is in fluid communication with the gaseous fuel engine 11 and not with the external supply of gaseous fuel 26, and the machine storage tanks 18b, 18c are in fluid communication with the external supply of gaseous fuel 26 and not with the gaseous fuel engine 11. This arrangement therefore isolates the machine storage tank 18a from the remaining machine storage tank 18b, 18c.

[0085] It shall be appreciated that in the embodiment of Figure 3, there is a first isolation valve 36 associated with each of the machine storage tanks 18a-c upstream of the tanks, and a second isolation valve 39 associated with each of the machine storage tanks 18a-c downstream of the tanks, so that each tank can be individually isolated from one or both the external supply of gaseous fuel 26 and gaseous fuel engine 11. In alternative embodiments, any suitable arrangement of valves and / or isolation devices may be used to at least partially isolate the machine storage tanks 18a-c.

[0086] In an alternative embodiment, in order to provide gaseous fuel to the machine power source 20, for example the prime mover 11 such as the hydrogen internal combustion engine 11, the external supply of gaseous fuel 26 may be used. In this embodiment, an additional gaseous fuel line compared to the embodiment of Figure 3 may be used to bypass the machine storage device 18 and supply gaseous fuel from the external supply of gaseous fuel 26 to the machine power source 20.

[0087] In embodiments where the external supply of gaseous fuel 26 is used to power the gaseous fuel compressor 28, the machine storage device 18 is configured to be isolated from the machine power source 20 during refuelling. In this embodiment, the valves 39 may be used to isolate the machine storage device 18 from the machine power source 20. This helps the machine storage device 18 to be compliant with such regulations / standards by providing gaseous fuel to the machine power source 20 whilst being refuelled. In this embodiment, all of the machine storage tanks 18a-c may be isolated from the machine power source 20, for example via the three isolation valves 39. Alternatively, a single valve 39 may be provided to isolate the machine storage tank 18a-c from the machine power source 20.

[0088] Using the external supply of gaseous fuel 26 to provide gaseous fuel to the machine power source 20 may help to speed up refuelling because gaseous fuel from the machine storage device 18 device does not need to be used as the fuel source.

[0089] As shown in Figure 3 the refuelling system 22 further comprises the controller 23 (e.g., a suitable microprocessor or logic circuit) in communication with a first pressure sensor 34a of the sensor arrangement 34a, 34b which measures or derives the pressure of the external supply of gaseous fuel 26 and a second pressure sensor 34b of the sensor arrangement 34a, 34b which measures or derives the pressure of the machine storage device 18. The controller 23 is configured to determine the flow of gaseous fuel from the external supply of gaseous fuel 26 to the machine storage device 18. In this embodiment, the first and second pressure sensors 34a, 34b measure or derive the pressure in each tank 26a-c of the external supply 26 and machine storage device. Based on the control logic described below, the controller 23 is further able to output control signals to operate the hydraulic valve 31 and / or provide an output to an indicator 37. The indicator 37 may be a visual indicator 37, such as a display or a dial 37, and / or an audio indicator 37, such as an alarm. The controller 23 is also configured in this embodiment to control operation of the isolation valves 36, 39 and to be able to start and stop the prime mover 11.

[0090] The communication between the controller 23, sensors 34a, 34b, hydraulic valve 31, indicator 37 and isolation valves 36, 39 may be wired, wireless or a combination of both (e.g. using a suitable communication protocol such as the CAN protocol).

[0091] Figure 5 illustrates an embodiment of the control logic followed by the refuelling system 22 to refuel the working machine 10.

[0092] In this embodiment, the refuelling system 22 is configured to automatically draw gaseous fuel through the gaseous fuel compressor 28 when it is determined that a flow of gaseous fuel to the machine storage device 18 is, or would be, below the threshold. When the gaseous fuel compressor 28 is powered by the machine power source 20, for example the hydrogen internal combustion engine 11, the gaseous fuel compressor 28 automatically draws gaseous fuel therethrough. The gaseous fuel drawn through the gaseous fuel compressor 28 outputs gas at a pressure greater than that of the machine storage device 18, and will therefore be drawn into the machine storage device 18.

[0093] At step 40, prior to refuelling commencing, the controller 23 determines whether the external supply of gaseous fuel 26 is coupled to the refuelling system utilising a suitable sensor (not shown).

[0094] At step 42, the controller 23 determines whether a flow of gaseous fuel from the external supply of gaseous fuel 26 to the machine storage device 18 is, or would be, below the threshold. In this embodiment the threshold is a pressure threshold - the point at which the pressure of the external supply of gaseous fuel 26 is equal to the pressure of the machine storage device 18. Alternatively, the threshold may be any point at which it is determined that the pressure differential is insufficient for adequate refuelling speed. This threshold (of flow or pressure) may be different at different times of the day or adjusted based on different usage scenarios. For example, a lower threshold may be acceptable overnight when slow refuelling is less problematic. The gaseous fuel from the external supply of gaseous fuel 26 may be drawn through the gaseous fuel compressor 28 when the controller 23 determines that the pressure of the external supply of gaseous fuel 26 has decreased, i.e. the pressure "would" fall below the threshold if refuelling continued through the first fuel circuit 30.

[0095] If flow is above the threshold, then gaseous fuel from the external supply of gaseous fuel 26 to the machine storage device 18 is through the first fuel circuit 30, as illustrated at step 44. At step 46, if refuelling is complete, e.g. as determined by a certain pressure being achieved in the machine storage device, the refuelling operation ends.

[0096] If refuelling is not complete, then the determination at step 42 is repeated periodically.

[0097] If flow from the external supply of gaseous fuel 26 to the machine storage device 18 is, or would be, below the threshold, then at step 48 the controller 23 determines whether the isolation function has taken place to isolate one tank 18a-c from the refuelling circuit 24, so as to be able to provide fuel to power the hydrogen IC engine 11, and at step 50 signals the opening and closing of the appropriate isolation valves 36, 39. The machine storage tank 18a-c to be isolated may be selected as the tank with the highest pressure as this has the least need for refuelling, and the greatest amount of fuel energy to support the refuelling of the remaining machine storage tanks.

[0098] The controller 23 then signals the starting of the hydrogen IC engine 11 if it is not already operating and opening of hydraulic valve 31 such that the gaseous fuel compressor 28 is powered by the machine power source 20 at step 52 and gaseous fuel is drawn through the second fuel circuit 32 at step 54.

[0099] At step 56, if refuelling is complete, the refuelling operation ends, and if refuelling is not complete, then gaseous fuel continues to be drawn through the second fuel circuit 32.

[0100] Whilst in this embodiment, pressure sensors 34a, 34b are used to determine the resultant flow without the intervention of the compressor 28, in other embodiments other parameters of the gaseous fuel may be used.

[0101] The sensor arrangement 34a, 34b is configured to measure a parameter indicative of the flow of gaseous fuel from the external supply of gaseous fuel 26 to the machine storage device 18. For example a sensor arrangement may include any one of, or any combination of a flow sensor, a pressure sensor, and / or a temperature sensor.

[0102] Whilst in this embodiment, the refuelling system 22 is configured to determine the first and second pressure, in alternative embodiments the refuelling system 22 may determine one of the first and second pressure.

[0103] In another embodiment, the sensor arrangement is configured to use one or more flow sensors, for example flow meters, to determine flow of gaseous fuel from the external supply of gaseous fuel 26 to the machine storage device 18. The flow sensor may be located at any suitable location on the refuelling circuit 24, for example near the coupling device 33 of the machine storage device 18. In this embodiment, the threshold is therefore a flow threshold, for example, a minimum allowable flow to the machine storage device 18. The one or more flow sensors may issue a signal to the controller 23.

[0104] In alternative embodiments, alternative sensor arrangements including ultrasonic sensors, optical sensors and / or temperature sensors may be used to measure or derive flow.

[0105] A further embodiment in which the hydrogen internal combustion engine 11 is used to power the gaseous fuel compressor 28' is illustrated in Figure 4, in which those parts that differ to the embodiment of Figure 3 are labelled with the suffix '. In this embodiment, the gaseous fuel compressor 28' may be a portable gaseous fuel compressor 28'. This arrangement has the advantage that the same gaseous fuel compressor 28' can be used to refuel a variety of different working machines 10. The gaseous fuel compressor 28' may be removably coupled to the refuelling circuit 24', for example using a coupling device 33b', 35b' and / or a coupling line. Any suitable coupling 33a', 35a' may be used to connect the gaseous fuel compressor 28' to the external supply of gaseous fuel, for example releasable couplings.

[0106] In order to power the gaseous fuel compressor 28', the gaseous fuel compressor 28' is connected to an auxiliary hydraulic circuit 27' of the hydraulic fluid circuit 25.

[0107] Flow of hydraulic fluid to the auxiliary hydraulic circuit 27' is controlled by a valve - e.g. a solenoid operated spool valve 31'. The hydraulic motor 21' of the gaseous fuel compressor 28' is thereby connected to the auxiliary hydraulic fluid circuit 27' by a coupling device 29', such as a known quick release coupling. The auxiliary hydraulic fluid circuit 27' is used to provide hydraulic fluid to the hydraulic motor 21' from the hydraulic fluid circuit 25. The auxiliary hydraulic fluid circuit 27' may be an auxiliary hydraulic fluid circuit ordinarily used for connecting to a load handling implement 15 and operating additional functions of the load handling implement - e.g. a hydraulically powered grab function.

[0108] In other respects operation of the refuelling system 22' of Figure 4 follows that of the first embodiment, i.e. as described in conjunction with the flowchart of Figure 5.

[0109] In a further alternative embodiment of portable fuel compressor (not shown), the hydraulic motor 21' powering the compressor 28' may be mechanically driven by the internal combustion engine 11. This embodiment may be particularly applicable to gaseous fuelled tractors which are typically provided with a power take off (PTO) shaft for the connection of mechanically powered implements at the rear and / or front thereof.

[0110] In a yet further alternative embodiment (not shown), the working machine 10 may include a machine power source 20 in the form of a hydrogen fuel cell 20. The hydrogen fuel cell may be configured to power the working machine 10 as a prime mover, or may be auxiliary to the prime mover. The hydrogen fuel cell 20 produces electrical power, and, in this embodiment, the gaseous fuel compressor 28' may be driven by an electric rather than hydraulic motor. It shall be appreciated that the electrically powered gaseous fuel compressor 28' may be portable, or alternatively may be integrated with the working machine 10.

[0111] In another embodiment, the machine power source 20 may be a battery (not shown). For example if the machine is a hybrid machine comprising an IC engine and a hybrid battery, the hybrid battery may be utilised to provide electrical power to operate the compressor.

[0112] It shall be further appreciated that the features described in relation to the embodiment of Figure 3, for example the isolation function, are also applicable to the embodiment of Figure 4, and the embodiment wherein the machine power source 20 is the hydrogen fuel cell 20. Furthermore, it shall be appreciated that the machine power source of Figures 3 and 4 may be a hydrogen fuel engine, or an alternative gaseous fuel engine. Whilst the embodiments described above utilise a controller 23 to automate operation of the refuelling system 22, 22' in other embodiments, the refuelling may be manually controlled by an operator. The refuelling system 22 may be configured to produce an indication to the operator that the flow of gaseous fuel to the machine storage device 18 is, or would be, below the threshold, for example via the indicator 37. The operator may then engage drive to the motor 21, 21' to operate the compressor 28, 28' until a desired pressure in the machine storage device 18 is achieved.

[0113] Alternatively or additionally, the first and second pressure sensors 34a, 34b may display the pressure reading on the indicator 37. Separate indicators 37 may be used to display the first and second pressures, or the same indicator 37 may be used. The operator may then draw gaseous fuel through the gaseous fuel compressor 28 by comparing the pressures displayed on or communicated by the indicators 37.

[0114] Where the machine storage device 18 and / or external supply of gaseous fuel 26 comprise more than one tank or vessel 26a-c, the control logic may be adjusted so that refuelling may be achieved with minimal use of the compressor 28 - e.g. by first refuelling the lower pressure tanks 18a-c from the lowest pressure external tanks 26a-c and then utilising progressively higher pressure external tanks 26a-c for refuelling until a situation is reached where no external tanks 26a-c remain at a suitable pressure and use of the compressor 28 is required.

[0115] Although the teachings have been described above with reference to one or more preferred embodiments, it will be appreciated that various changes or modifications may be made without departing from the scope as defined in the appended claims.

Claims

Claims1. A refuelling system for a working machine, the refuelling system comprising: a refuelling circuit configured to be coupled to an external supply of gaseous fuel, wherein the refuelling circuit comprises: a machine storage device configured to store a gaseous fuel under pressure on the working machine; and a gaseous fuel compressor configured to be powered by a machine power source of the working machine; wherein the refuelling circuit is configured to provide gaseous fuel to the machine storage device from the external supply of gaseous fuel; and wherein the refuelling circuit is configured to direct gaseous fuel through the gaseous fuel compressor when it is determined that a flow of gaseous fuel from the external supply of gaseous fuel to the machine storage device is, or would be, below a threshold.

2. The refuelling system according to claim 1, wherein the refuelling system is configured to automatically direct gaseous fuel through the gaseous fuel compressor when it is determined that a flow of gaseous fuel to the machine storage device is, or would be, below the threshold.

3. The refuelling system according to claim 1 or claim 2, wherein the refuelling system is configured to produce an indication to an operator that the flow of gaseous fuel from the external supply of gaseous fuel to the machine storage device is, or would be, below the threshold.

4. The refuelling system according to any preceding claim, wherein the refuelling circuit comprises a first fuel circuit for refuelling under the pressure of the gaseous fuel in the external supply and a second fuel circuit, and wherein the gaseous fuel compressor is part of the second fuel circuit.

5. The refuelling system according to any preceding claim, wherein the gaseous fuel compressor is configured to automatically draw gaseous fuel therethrough when the gaseous fuel compressor is powered by the machine power source.

6. The refuelling system according to any preceding claim, wherein the machine storage device is configured to provide gaseous fuel to power a prime mover, for example a gaseous fuel engine, during operation of the working machine.

7. The refuelling system according to any preceding claim, wherein at least a portion of the machine storage device is configured to be isolated from the machine power source during refuelling.

8. The refuelling system according to claim 7, wherein the refuelling circuit comprises a gaseous fuel line connected to the gaseous fuel compressor, and wherein the gaseous fuel line is configured to bypass the machine storage device and supply gaseous fuel to the machine power source from the external supply of gaseous fuel during refuelling.

9. The refuelling system according to any preceding claim, wherein the machine storage device comprises a plurality of machine storage tanks or vessels.

10. The refuelling system according to claim 9, wherein at least one of the plurality of machine storage tanks or vessels is isolated from the remainder of the machine storage tanks or vessels during refuelling.

11. The refuelling system according to claim 10, wherein the at least one of the plurality of machine storage tanks or vessels is configured to power the machine power source during refuelling.

12. The refuelling system of any preceding claim, wherein the refuelling system is configured to determine a first pressure indicative of the external supply of gaseous fuel, and / or a second pressure indicative of the machine storage device.

13. The refuelling system of claim 12, wherein the refuelling system is configured to direct gaseous fuel to the machine storage device via the gaseous fuel compressor when the refuelling system determines that the first pressure is less than or equal to the second pressure or when therefuelling system determines that the first pressure is less than or equal to the threshold.

14. The refuelling system of claim 12 or claim 13 when dependent on claim 3, wherein the refuelling system is configured to produce an indication to the operator indicative of the first and / or second pressures.

15. The refuelling system according to any preceding claim, wherein the refuelling system comprises a sensor arrangement configured to measure a parameter indicative of the flow of gaseous fuel from the external supply of gaseous fuel to the machine storage device.

16. The refuelling system according to claim 15, wherein the sensor arrangement comprises at least one of a flow sensor, a pressure sensor, a temperature sensor, an ultrasonic sensor and / or an optical sensor.

17. The refuelling system according to any preceding claim, wherein the refuelling system comprises a controller configured to determine the flow of gaseous fuel from the external supply of gaseous fuel to the machine storage device.

18. The refuelling system according to any preceding claim, wherein the gaseous fuel compressor is piston pump or a diaphragm pump configured to be coupled to the machine power source.

19. The refuelling system according to any preceding claim, wherein the rated pressure capacity of the machine storage device is at least 35MPa.

20. A working machine comprising: a machine power source configured to provide power to components of the working machine; a refuelling circuit configured to be coupled to an external supply of gaseous fuel, wherein the refuelling circuit comprises: a machine storage device configured to store a gaseous fuel under pressure on the working machine; anda gaseous fuel compressor configured to be powered by the machine power source, wherein the gaseous fuel compressor is located on the working machine; wherein the refuelling circuit is configured to provide gaseous fuel to the machine storage device from the external supply of gaseous fuel; and wherein the refuelling circuit is configured to direct gaseous fuel through the gaseous fuel compressor when it is determined that a flow of gaseous fuel from the external supply of gaseous fuel to the machine storage device is, or would be, below a threshold.

21. The working machine according to claim 20, wherein the machine power source is at least one of a gaseous fuel engine, a battery or a hydrogen fuel cell.

22. The working machine according to claim 20 or claim 21, wherein the working machine comprises a prime mover, for example a gaseous fuel engine, and wherein the machine storage device is configured to provide gaseous fuel to power the prime move during operation of the working machine.

23. The working machine according to any one of claim 20 to claim 22, wherein the working machine is an excavator, a wheeled loader, a telehandler, a backhoe loader, a tractor or a mobile electric generator.

24. A method of refuelling a working machine comprising a machine power source and a refuelling system, wherein the refuelling system comprises a refuelling circuit, a machine storage device configured to store a gaseous fuel under pressure on the working machine, the method comprising the steps of: coupling an external supply of gaseous fuel to the refuelling circuit; running the machine power source; providing gaseous fuel from the external supply of gaseous fuel to the machine storage device; determining that a flow of gaseous fuel from the external supply of gaseous fuel to the machine storage is, or would be, below a threshold; and powering the gaseous fuel compressor using the machine power source and directing gaseous fuel through the gaseous fuel compressor.

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