METHOD OF DIAGNOSING A FUEL GAS SUPPLY ARRANGEMENT, CONTROL ARRANGEMENT, COMPUTER PROGRAM, COMPUTER-READABLE MEDIUM, FUEL GAS SUPPLY ARRANGEMENT, AND VEHICLE

Abstract

 A method (100) of diagnosing a fuel gas supply arrangement (1, 1') is disclosed. The fuel gas supply arrangement (1, 1') comprises a pressure tank (3), a fuel pressure reducer (6, 6'), a first conduit assembly (c1) connecting an inlet (9) of the fuel pressure reducer (6, 6') to the pressure tank (3), and a second conduit assembly (c2) connecting an outlet (9') of the fuel pressure reducer (6, 6') to propulsion system (60). The method (100) comprises the steps of obtaining (110) pressure data at multiple consecutive occasions, wherein the pressure data is representative of a pressure in the second conduit assembly (c2) during zero-flow conditions over the fuel pressure reducer (6, 6'), and diagnosing (130) an operational performance of the fuel pressure reducer (6, 6') by analysing the obtained pressure data. The present disclosure further relates to a control arrangement (21), a computer program, a computer-readable medium (200), a fuel gas supply arrangement (1, 1'), and a vehicle (2).

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a method of diagnosing a fuel gas supply arrangement, wherein the fuel gas supply arrangement is configured to supply fuel gas to a propulsion system of a vehicle. The present disclosure further relates to a control arrangement for a fuel gas supply arrangement, a computer program, a computer-readable medium, a fuel gas supply arrangement for a vehicle, and a vehicle comprising a fuel gas supply arrangement.

BACKGROUND

[0002] Fuel gas is any one of a number of fuels that under ordinary ambient temperature and pressure conditions are gaseous. Many fuel gases are composed of hydrocarbons, such as methane, butane, or propane, or mixtures thereof. Some examples of different types of fuel gas are compressed natural gas (CNG), liquified natural gas (LNG), and Hydrogen (H2).

[0003] Natural gas is mainly composed of methane and may be found above oil deposits or may be collected from renewable energy sources where it is known as biogas. Biogas can be produced from raw materials such as agricultural waste, manure, municipal waste, plant material, sewage, green waste, food waste, landfills, or wastewater treatment plants. Compressed natural gas (CNG) is a term used for describing natural gas, biogas, or a mixture thereof, being compressed in pressure tanks. The compressed natural gas may be stored at a pressure of around 180 - 200 bars at fully filled pressure tanks, and may decrease to approximately 15 bar, which is normally considered an empty system for a vehicle propelled by said gas.

[0004] The term liquified natural gas (LNG) is used for describing natural gas, biogas, or a mixture thereof, in liquid form. The natural gas, biogas, or mixture thereof, is usually liquified by being cooled down to liquid form for ease and safety of storage or transport. Liquefied natural gas is normally stored in pressure tanks of a fuel gas supply arrangement of the vehicle at low temperatures, such as at temperatures around -130 degrees Celsius. In this manner, the gas can be stored in liquid form at relatively low pressures which accordingly allows more gas to be accommodated in the pressure tanks at lower pressures. Such pressure tanks can also be referred to as cryogenic tanks because they are configured to store the fuel gas in liquid form at cryogenic temperatures.

[0005] In systems operating with liquified natural gas, the fuel gas is commonly heated by a heat exchanger arranged on or close to the pressure tank so that a propulsion system can be fed with a gaseous fuel not being too cold. That is, a propulsion system, as well as components arranged between the pressure tank and an internal combustion engine, are sensitive to low temperatures.

[0006] Hydrogen (H2) is a zero-emission fuel when burned with oxygen and can be produced from a variety of resources, making it a promising alternative for the future. Hydrogen can also be used to generate electricity in a fuel cell, wherein the electricity is used to provide motive power to a vehicle in one or more electric machines of the vehicle. However, challenges related to production, storage, fuelling infrastructure, and vehicle cost remain to be addressed to facilitate wider adoption. Storing hydrogen in vehicles presents challenges due to its physical properties. Hydrogen has a low energy density by volume, requiring effective storage methods to hold enough fuel for practical vehicle range. One method of storing hydrogen on vehicles is in high-pressure tanks, typically at pressures of 350-700 bar. The tanks are designed to be strong to contain the high-pressure hydrogen safely.

[0007] As indicated above, fuel gas is commonly stored in pressure tanks of a vehicle in a pressure range of approximately 15 - 700 bar. However, fuel systems of propulsion systems, such as injection systems of internal combustion engines and fuel management systems of fuel cells, are normally designed to operate at a pressure of around 5 - 9 bar. Therefore, the pressure of the fuel gas from the pressure tanks must be reduced before the gas reaches the propulsion system of the vehicle. This is commonly achieved using one or more fuel pressure reducers, also known as pressure regulators, or simply regulators.

[0008] Such fuel pressure reducers are used to regulate a higher range of pressures from the pressure tanks to a lower pre-set pressure. A fuel pressure reducer can be said to function as a specialized valve. On one side, it sustains high pressure, known as the upstream side, while the other side accommodates lower pressure, also known as the downstream side. Commonly, a fuel pressure reducer comprises a valve comprising a valve member, a valve seat and a spring connected to the valve member. Moreover, a fuel pressure reducer normally comprises a piston or membrane connected to the valve member and to a chamber connected to the downstream side of the fuel pressure reducer. The valve member moves between an open and a closed position relative to the valve seat depending on the movement of the diaphragm or piston. When the pressure in the downstream chamber drops below the pre-set pressure, the valve member is moved towards the open position by the biasing force of the spring to allow more gas to flow into the downstream side of the fuel pressure reducer. If the downstream pressure reaches above the pre-set pressure, the valve member is moved towards the closed position by the pressure acting on a certain area of the diaphragm or piston.

[0009] As understood from the above, the spring force and the surface area influence the pre-set pressure. When no flow occurs, an equilibrium is achieved among the upstream pressure, downstream pressure, and the force exerted by the spring. When the gas in the downstream volume is consumed or removed, this equilibrium is disrupted, causing the valve to be moved by the upstream pressure, which consequently opens the valve. This action refills the downstream gas volume until the force equilibrium is reestablished. Under steady flow conditions, this means that the valve of the fuel pressure reducer maintains a certain degree of openness, creating an orifice with a certain size.

[0010] If the flow increases or decreases, the force equilibrium is disturbed, and the fuel pressure reducer adjusts the orifice size between the valve member and the valve seat until a balance is regained. In the absence of flow, the fuel pressure reducer closes, pressing the valve piston onto its corresponding seat to prevent any increase in pressure above the pre-set pressure.

[0011] If a leak develops in the valve, the pressure in the downstream volume will increase, and the pushing force on the diaphragm or piston will increase until the leak ceases. A fuel gas supply arrangement normally comprises a pressure relief valve (PRV) designed to automatically release gas if the pressure at a downstream side of the fuel pressure reducer exceeds a pressure limit, thereby protecting the system from potential damage due to over pressurization. The pressure relief valve accomplishes this by opening when an internal force generated by the pressure overcomes the force exerted by a spring, or similar mechanism, holding the valve closed.

[0012] A pressure relief valve may also be referred to as a safety valve, a relief valve, a safety relief valve, a pressure safety valve (PSV), or an overflow valve. Regardless of the terminology used, the primary function remains the same, namely to provide a safety mechanism that mitigates the risk of system failure due to excessive pressures.

[0013] If a substantial leak occurs over a fuel pressure reducer, a pressure relief valve (PRV) may open, releasing gas into the atmosphere. Normally, the fuel pressure reducer is warmed by engine coolant to offset the cold generated by the expanding gas.

[0014] Over the course of the operational life of a fuel pressure reducer, as debris flows past the valve member and valve seat, it may incur minor scratches, indentations, and the like formations on sealing surfaces of the valve member and the valve seat. These irregularities can result in minor leaks past the seat during periods of zero flow, such as when the engine is turned off.

[0015] As these leaks gradually increase, the pressure during shut-off also rises over time, exerting greater forces on the valve member. These amplified forces can deform the sealing surfaces of the valve member, and/or of the valve seat. Moreover, fuel injectors of the fuel injection system of the engine may become inoperable if the supply pressure is too high which leads to a vehicle standstill, also referred to as a vehicle off-road (VOR) situation.

[0016] In the long run, if wear and leakage in the fuel pressure reducer remains unattended, the fuel pressure reducer may start to leak to such an extent that it begins to release gas through the pressure relief valve (PRV). The fuel pressure reducer will absorb the cold from the expanding gas due to the Joule-Thomson effect. However, if this occurs when the engine is off, and thus not being warmed by the coolant, this cooling effect could cause O-rings to drop below their design temperature. This can impair the functionality of the fuel pressure reducer, leading to free-flowing gas. This can either permanently damage downstream components or the fuel pressure reducer itself, potentially causing them to burst in the worst-case scenario, or gradually deplete the fuel gas in the piping through the safety relief valve over time. Both scenarios may lead to a vehicle standstill.

[0017] Moreover, the release of fuel gas into the surroundings can result in adverse effects on the environment. Many gaseous fuels comprise potent greenhouse gases. As an example, methane is a potent greenhouse gas and is an even more potent greenhouse gas than carbon dioxide due to the greater global-warming potential of methane. The lifetime of atmospheric methane is relatively short when compared to carbon dioxide, with a half-life of about 7 years. However, it is more efficient at trapping heat in the atmosphere. Therefore, a given quantity of methane has approximately 84 times the global-warming potential of carbon dioxide over a 20-year period and approximately 28 times over a 100-year period.

[0018] Moreover, the release of fuel gas into the surroundings can cause safety concerns because of the flammability thereof.

SUMMARY

[0019] It is an object of the present invention to overcome, or at least alleviate, at least some of the above-mentioned problems and drawbacks.

[0020] According to a first aspect of the invention, the object is achieved by a method of diagnosing a fuel gas supply arrangement, wherein the fuel gas supply arrangement is configured to supply fuel gas to a propulsion system of a vehicle. The fuel gas supply arrangement comprises a pressure tank configured to store the fuel gas, a fuel pressure reducer, a first conduit assembly connecting an inlet of the fuel pressure reducer to the pressure tank, and a second conduit assembly connecting an outlet of the fuel pressure reducer to the propulsion system. The method comprises the steps of:

• obtaining pressure data at multiple consecutive occasions, wherein the pressure data is representative of a pressure in the second conduit assembly during zero-flow conditions over the fuel pressure reducer, and
• diagnosing an operational performance of the fuel pressure reducer by analysing the obtained pressure data.

[0021] Thereby, a method is provided capable of providing a reliable diagnosis of the operational performance of the fuel pressure reducer in a simple and efficient manner. This is because the step of obtaining pressure data being representative of a pressure in the second conduit assembly during zero-flow conditions over the fuel pressure reducer at multiple consecutive occasions can indicate if the pressure in the second conduit assembly is developing over time during zero-flow conditions over the fuel pressure reducer.

[0022] Such development of the pressure in the second conduit assembly can give a clear indication of the operational performance of the fuel pressure reducer and if a valve member or a valve seat of the fuel pressure reducer has been subjected to wear and tear. Moreover, by diagnosing the operational performance of the fuel pressure reducer by analysing the obtained pressure data, the diagnosis can indicate how the pressure in the second conduit assembly is likely to develop to form the basis of an accurate recommendation when to schedule a workshop visit for servicing or replacing the fuel pressure reducer.

[0023] Moreover, the pressure data can be obtained in a simple and efficient manner for example by using input from a pressure sensor configured to obtain a current pressure in the second conduit assembly. Thereby, the method is capable of providing the reliable diagnosis of the operational performance of the fuel pressure reducer in a simple and efficient manner as explained above.

[0024] In addition, a method is provided having conditions for avoiding leaks of fuel gas from the fuel gas supply arrangement, for example via a pressure relief valve thereof. As a further result, a method is provided having conditions for reducing the environmental impact of a vehicle comprising the fuel gas supply arrangement as well as conditions for improving the operational safety of the vehicle.

[0025] Furthermore, a method is provided having conditions for avoiding vehicle standstills caused by a malfunctioning fuel pressure reducer.

[0026] Accordingly, a method is provided overcoming, or at least alleviating, at least some of the above-mentioned problems and drawbacks. As a result, the above-mentioned object is achieved.

[0027] Optionally, the step of obtaining the pressure data comprises:

• obtaining the pressure data at multiple consecutive occasions such that at least a number of the multiple consecutive occasions occur at different operational instances of the vehicle.

[0028] Thereby, reliable diagnoses of the operational performance of the fuel pressure reducer can be further ensured. This is because pressure data obtained at different operational instances of the vehicle can give clear indications of how the pressure in the second conduit assembly develops. As a further result, the diagnoses can in a more reliable manner indicate how the pressure in the second conduit assembly is likely to develop to thereby form the basis of more accurate recommendations when to schedule a workshop visit for servicing or replacing the fuel pressure reducer.

[0029] Optionally, the step of obtaining the pressure data comprises:

• obtaining the pressure data at multiple consecutive occasions such that at least a number of the multiple consecutive occasions occur during a respective time period between an activation of the vehicle and activation of the propulsion system.

[0030] Thereby, reliable diagnoses of the operational performance of the fuel pressure reducer can be further ensured. This is because pressure data obtained during a respective time period between an activation of the vehicle and activation of the propulsion system can ensure that the obtaining pressure data is accurate and is representative of a current operational state of the fuel pressure reducer without any disturbances from flow transients. Moreover, the pressure data obtained during a time period between an activation of the vehicle and activation of the propulsion system may indicate even slower leakages occurring over time than what can be monitored for example immediately after shutting down the propulsion system. In addition, due to these features, the pressure data can be obtained in a consistent manner where the obtained pressure data is collected at similar instances which provides conditions for reliable diagnoses of the operational performance of the fuel pressure reducer.

[0031] The activation of the propulsion system, as referred to herein, may correspond to a point in time in which a fuel consumption phase of the propulsion system is initiated. In embodiments in which the propulsion system comprises an internal combustion engine, the activation of the propulsion system, as referred to herein, may encompass cranking of the internal combustion engine. In embodiments in which the propulsion system comprises a fuel cell, the activation of the propulsion system, as referred to herein, may encompass an initiation of a fuel supply phase to the fuel cell.

[0032] Optionally, the step of diagnosing the operational performance of the fuel pressure reducer comprises:

• estimating a remaining operational lifespan of the fuel pressure reducer based on the obtained pressure data.

[0033] Thereby, even more accurate recommendations can be provided of when to schedule a workshop visit for servicing or replacing the fuel pressure reducer.

[0034] Optionally, the step of estimating the remaining operational lifespan comprises:

• estimating at least one of a remaining time, a remaining travel distance, a remaining number of operational instances, and a remaining amount of fuel supplied to the propulsion system before a predetermined pressure is reached in the second conduit assembly.

[0035] Thereby, even more accurate recommendations can be provided of when to schedule a workshop visit for servicing or replacing the fuel pressure reducer. This is because the analysis of the obtained pressure data can indicate how the pressure in the second conduit assembly is likely to develop and thereby also at least one of a remaining time, a remaining travel distance, a remaining number of operational instances, and a remaining amount of fuel supplied to the propulsion system before the predetermined pressure is reached in the second conduit assembly.

[0036] According to some embodiments, at least one of the remaining time, the remaining travel distance, the remaining number of operational instances, and the remaining amount of fuel supplied to the propulsion system may be included in an output of a recommendation of when to schedule a workshop visit for servicing or replacing the fuel pressure reducer. Thus, according to such embodiments, the user of the vehicle can in a simpler and more convenient manner plan for such a workshop visit.

[0037] Optionally, the fuel gas supply arrangement comprises a pressure relief valve configured to vent gas from the second conduit assembly when the pressure in the second conduit assembly exceeds a pressure limit, wherein the pressure limit is higher than the predetermined pressure. Thereby, it can be further ensured that a recommendation of when to schedule a workshop visit for servicing or replacing the fuel pressure reducer is performed prior to a situation in which the operational performance of the fuel pressure reducer has been deteriorated to a point at which the pressure relief valve vents gas from the second conduit assembly. Accordingly, in this manner, a method is provided having improved conditions for avoiding leaks of fuel gas from the fuel gas supply arrangement. As a further result, a method is provided having improved conditions for reducing the environmental impact of a vehicle comprising the fuel gas supply arrangement as well as improved conditions for improving the operational safety of the vehicle.

[0038] Optionally, the method comprises:

• scheduling a workshop visit based on the estimated remaining operational lifespan of the fuel pressure reducer.

[0039] Thereby, a method is provided capable of providing accurate recommendations of when to visit a workshop for servicing or replacing the fuel pressure reducer. As a further result, a method is provided having conditions for reducing the environmental impact of a vehicle comprising the fuel gas supply arrangement as well as conditions for improving the operational safety of the vehicle.

[0040] Optionally, the fuel gas supply arrangement comprises a pressure relief valve configured to vent gas from the second conduit assembly when the pressure in the second conduit assembly exceeds a pressure limit, and wherein the method comprises:

• setting a fault indicator for the pressure relief valve if the data indicates that the pressure in the second conduit assembly is within a predetermined pressure range, below the pressure limit, at a number of consecutive occasions without any further increase in pressure.

[0041] Thereby, the fault indicator can be set in a reliable manner to indicate that service or replacement of the pressure relief valve is needed. This is because the pressure relief valve can be determined to open at a too low pressure if the data indicates that the pressure in the second conduit assembly is within the predetermined pressure range at a number of consecutive occasions without any further increase in pressure. As a further result of these features, leakages of fuel gas from the fuel gas supply arrangement can be further avoided. Accordingly, a method is provided having improved conditions for reducing the environmental impact of a vehicle comprising the fuel gas supply arrangement as well as improved conditions for improving the operational safety of the vehicle.

[0042] According to a second aspect of the invention, the object is achieved by a control arrangement for a fuel gas supply arrangement, wherein the fuel gas supply arrangement is configured to supply fuel gas to a propulsion system of a vehicle, the fuel gas supply arrangement comprising a pressure tank configured to store the fuel gas, a fuel pressure reducer, a first conduit assembly connecting an inlet of the fuel pressure reducer to the pressure tank, a second conduit assembly connecting an outlet of the fuel pressure reducer to the propulsion system, and a control arrangement, wherein the control arrangement is configured to:

• obtain pressure data at multiple consecutive occasions, wherein the pressure data is representative of a pressure in the second conduit assembly during zero-flow conditions over the fuel pressure reducer, and
• diagnose an operational performance of the fuel pressure reducer by analysing the obtained pressure data.

[0043] Thereby, a control arrangement is provided capable of providing a reliable diagnosis of the operational performance of the fuel pressure reducer in a simple and efficient manner. This is because the obtained pressure data being representative of a pressure in the second conduit assembly during zero-flow conditions over the fuel pressure reducer at multiple consecutive occasions can indicate if the pressure in the second conduit assembly is developing over time during zero-flow conditions over the fuel pressure reducer.

[0044] Such development of the pressure in the second conduit assembly can give a clear indication of the operational performance of the fuel pressure reducer and if a valve member or a valve seat of the fuel pressure reducer has been subjected to wear and tear. Moreover, by diagnosing the operational performance of the fuel pressure reducer by analysing the obtained pressure data, the diagnosis can indicate how the pressure in the second conduit assembly is likely to develop to form the basis of an accurate recommendation when to schedule a workshop visit for servicing or replacing the fuel pressure reducer.

[0045] Moreover, the pressure data can be obtained in a simple and efficient manner for example by using input from a pressure sensor configured to obtain a current pressure in the second conduit assembly. Thereby, the control arrangement is capable of providing the reliable diagnosis of the operational performance of the fuel pressure reducer in a simple and efficient manner as explained above.

[0046] In addition, a control arrangement is provided having conditions for avoiding leaks of fuel gas from the fuel gas supply arrangement, for example via a pressure relief valve thereof. As a further result, a control arrangement is provided having conditions for reducing the environmental impact of a vehicle comprising the fuel gas supply arrangement as well as conditions for improving the operational safety of the vehicle.

[0047] Furthermore, a control arrangement is provided having conditions for avoiding vehicle standstills caused by a malfunctioning fuel pressure reducer.

[0048] Accordingly, a control arrangement is provided overcoming, or at least alleviating, at least some of the above-mentioned problems and drawbacks. As a result, the above-mentioned object is achieved.

[0049] It will be appreciated that the various embodiments described for the method are all combinable with the control arrangement as described herein. That is, the control arrangement according to the second aspect of the present disclosure may be configured to perform any one of the method steps of the method according to the first aspect of the present disclosure.

[0050] According to a third aspect of the invention, the object is achieved by a computer program comprising instructions to cause the control arrangement according to the second aspect of the invention execute the steps of the method according to the first aspect of the invention. Thereby, a computer program is provided which provides conditions for overcoming, or at least alleviating, at least some of the above-mentioned drawbacks. As a result, the above-mentioned object is achieved.

[0051] According to a fourth aspect of the invention, the object is achieved by a computer-readable medium having stored thereon the computer program according to the third aspect of the invention. Thereby, a computer-readable medium is provided which provides conditions for overcoming, or at least alleviating, at least some of the above-mentioned drawbacks. As a result, the above-mentioned object is achieved.

[0052] According to a fifth aspect of the invention, the object is achieved by a fuel gas supply arrangement for a vehicle, wherein the fuel gas supply arrangement is configured to supply fuel gas to a propulsion system of the vehicle. The fuel gas supply arrangement comprises a pressure tank configured to store the fuel gas, a fuel pressure reducer, a first conduit assembly connecting an inlet of the fuel pressure reducer to the pressure tank, a second conduit assembly connecting an outlet of the fuel pressure reducer to the propulsion system, and a control arrangement configured to:

• obtain pressure data at multiple consecutive occasions, wherein the pressure data is representative of a pressure in the second conduit assembly during zero-flow conditions over the fuel pressure reducer, and
• diagnose an operational performance of the fuel pressure reducer by analysing the obtained pressure data.

[0053] Thereby, a fuel gas supply arrangement is provided capable of providing a reliable diagnosis of the operational performance of the fuel pressure reducer in a simple and efficient manner. This is because the obtained pressure data being representative of a pressure in the second conduit assembly during zero-flow conditions over the fuel pressure reducer at multiple consecutive occasions can indicate if the pressure in the second conduit assembly is developing over time during zero-flow conditions over the fuel pressure reducer.

[0054] Moreover, a fuel gas supply arrangement is provided having conditions for avoiding leaks of fuel gas from the fuel gas supply arrangement, for example via a pressure relief valve thereof. As a further result, a fuel gas supply arrangement is provided having conditions for reducing the environmental impact of a vehicle comprising the fuel gas supply arrangement as well as conditions for improving the operational safety of the vehicle.

[0055] Furthermore, a fuel gas supply arrangement is provided having conditions for avoiding vehicle standstills caused by a malfunctioning fuel pressure reducer.

[0056] Accordingly, a fuel gas supply arrangement is provided overcoming, or at least alleviating, at least some of the above-mentioned problems and drawbacks. As a result, the above-mentioned object is achieved.

[0057] According to a sixth aspect of the invention, the object is achieved by a vehicle comprising a propulsion system, wherein the vehicle comprises a fuel gas supply arrangement according to the fifth aspect of the invention, and wherein the fuel gas supply arrangement is configured to supply fuel gas to the propulsion system of the vehicle.

[0058] Since the vehicle comprises a fuel gas supply arrangement according to the fifth aspect of the invention, a vehicle is provided overcoming, or at least alleviating, at least some of the above-mentioned problems and drawbacks. As a result, the above-mentioned object is achieved.

[0059] Optionally, the vehicle is a heavy road vehicle, such as a truck or a bus. Thereby, a heavy road vehicle is provided having at least some of the above-mentioned advantages.

[0060] Further features of, and advantages with, the present invention will become apparent when studying the appended claims and the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Various aspects of the invention, including its particular features and advantages, will be readily understood from the example embodiments discussed in the following detailed description and the accompanying drawings, in which:

Fig. 1 schematically illustrates a vehicle according to some embodiments,

Fig. 2 schematically illustrates a propulsion system and a fuel gas supply arrangement of the vehicle illustrated in Fig. 1,

Fig. 3 schematically illustrates the propulsion system of the vehicle illustrated in Fig. 1, and a fuel gas supply arrangement according to some further embodiments,

Fig. 4 schematically illustrates a method of diagnosing a fuel gas supply arrangement of a vehicle, and

Fig. 5 illustrates a computer-readable medium according to some embodiments.

DETAILED DESCRIPTION

[0062] Aspects of the present invention will now be described more fully. Like reference signs refer to like elements throughout. Well-known functions or constructions will not necessarily be described in detail for brevity and/or clarity.

[0063] Fig. 1 schematically illustrates a vehicle 2 according to some embodiments. According to the illustrated embodiments, the vehicle 2 is a truck, i.e., a type of heavy road vehicle as well as a type of heavy commercial vehicle. According to further embodiments, the vehicle 2, as referred to herein, may be another type of heavy or lighter type of manned or unmanned vehicle for land- or water-based propulsion such as a lorry, a bus, a construction vehicle, a tractor, a car, a boat, a ship, or the like.

[0064] The vehicle 2 comprises a propulsion system 60. According to the illustrated embodiments, the propulsion system 60 of the vehicle 2 comprises an internal combustion engine 5. As an alternative, or in addition, the propulsion system 60 may comprise one or more electric propulsion motors. The propulsion system 60 is configured to provide motive power to the vehicle 2 via wheels 47 of the vehicle 2.

[0065] The vehicle 2 comprises a fuel gas supply arrangement 1 configured to supply fuel gas to the propulsion system 60 of the vehicle 2, as is further explained herein. The fuel gas supply arrangement 1 comprises a pressure tank 3 configured to accommodate pressurized fuel gas. The pressure tank 3 may be configured to store fuel gas at a pressure within the range of 15 - 700 bar. The pressure tank 3 may also be referred to as a pressure vessel, a pressure container, a pressurized storage tank, or the like. In Fig. 1, the fuel gas supply arrangement 1 of the vehicle 2 is illustrated as comprising one pressure tank 3. However, the fuel gas supply arrangement 1 of the vehicle 2 may comprise more than one pressure tank 3.

[0066] Fig. 2 schematically illustrates the propulsion system 60 and the fuel gas supply arrangement 1 of the vehicle 2 illustrated in Fig. 1. Below, simultaneous reference is made to Fig. 1 and Fig. 2, if not indicated otherwise.

[0067] As mentioned above, according to the illustrated embodiments, the propulsion system 60 comprises an internal combustion engine 5. For reasons of brevity and clarity, the internal combustion engine 5 is in some places herein referred to as "the engine 5".

[0068] The engine 5 is configured to operate on fuel gas from the pressure tank 3. The wording fuel gas, as used herein, may encompass any type of fuel that under ordinary ambient temperature and pressure conditions are gaseous and which can be stored at pressure in the pressure tank 3 and can be combusted in an internal combustion engine 5 to produce useful work. Examples of such gaseous fuels are compressed natural gas (CNG), liquified natural gas (LNG), Liquefied Petroleum Gas (LPG), Hydrogen (H2), Biogas, and Syngas.

[0069] According to the illustrated embodiments, the internal combustion engine 5 is a four-stroke internal combustion engine. The engine 5 may be a so called Otto engine, also referred to as a spark-ignition engine, comprising an ignition device, such as a spark plug, configured to ignite an air fuel mixture in combustion chambers of the engine 5. The fuel gas may be mixed with air by a number of fuel injectors of a fuel injection system 4 of the engine before the air enters the combustion chambers of the engine 5.

[0070] According to further embodiments, the engine 5 may operate with compression ignition. In other words, the engine 5 may be a type of compression ignition engine. According to such embodiments, a small amount of a liquid fuel, such as diesel or a diesel-like fuel, may be used as a pilot for initiating combustion whereas the majority of the released energy comes from combustion of fuel gas supplied to the engine 5 via the fuel gas supply arrangement 1. These types of engines can also be referred to as Bi-fuel engines, dual fuel engines, and the like.

[0071] The engine 5 further comprises a cooling system 32. The cooling system 32 comprises coolant channels, a coolant pump configured to pump coolant, such as a water/glycol mixture through the cooling system 32, and a radiator 34 configured to radiate heat from the cooling system 32 to the surroundings.

[0072] According to further embodiments, the propulsion system 60 of the vehicle 2 may comprise a fuel cell, wherein the fuel cell is configured to generate electricity using oxygen and hydrogen stored in the pressure tank 3, and wherein the electricity is used to provide motive power to the vehicle 2 using one or more electric propulsion motors of the vehicle 2.

[0073] The fuel gas supply arrangement 1 comprises a fuel pressure reducer 6. As is further explained below, the fuel pressure reducer 6 is configured to reduce the pressure of the fuel gas supplied from the pressure tank 3 before the fuel gas is supplied to the propulsion system 60 of the vehicle 2. In embodiments in which the propulsion system 60 of the vehicle 2 comprises an engine 5, the fuel pressure reducer 6 is configured to reduce the pressure of the fuel gas supplied from the pressure tank 3 before the fuel gas is supplied to the fuel injection system 4 of the engine 5. In embodiments in which the propulsion system 60 of the vehicle 2 comprises a fuel cell, the fuel pressure reducer 6 may be configured to reduce the pressure of the fuel gas supplied from the pressure tank 3 before the fuel gas is supplied to a fuel management system of the fuel cell. The fuel pressure reducer 6 may also be referred to as a pressure regulator, fuel gas pressure regulator, or simply a regulator.

[0074] The fuel pressure reducer 6 comprises an inlet 9 and a first conduit assembly c1, wherein the inlet 9 of the fuel pressure reducer 6 is connected to the pressure tank 3 via the first conduit assembly c1. In other words, the first conduit assembly c1 connects the inlet 9 of the fuel pressure reducer 6 to the pressure tank 3.

[0075] The fuel gas supply arrangement 1 further comprises a valve v1 arranged on, at, or in a region of, the pressure tank 3. The valve v1 is controllable to an open state in which a fluid connection is open between the pressure tank 3 and the inlet 9 of the fuel pressure reducer 6. Moreover, the valve v1 is controllable to a closed state in which the valve v1 closes the connection between the pressure tank 3 and the inlet 9 of the fuel pressure reducer 6.

[0076] The fuel pressure reducer 6 further comprises an outlet 9' and a second conduit assembly c2. According to the illustrated embodiments, the outlet 9' of the fuel pressure reducer 6 is connected to the fuel injection system 4 of the engine 5. In other words, according to the illustrated embodiments, the second conduit assembly c2 connects the outlet 9' of the fuel pressure reducer 6 to the fuel injection system 4 of the engine 5. In embodiments in which the propulsion system 60 of the vehicle 2 comprises a fuel cell, the outlet 9' of the fuel pressure reducer 6 may be connected to a fuel management system of the fuel cell.

[0077] According to the illustrated embodiments, the fuel pressure reducer 6 comprises a valve member 11 and a valve seat 12. The valve member 11 is movably arranged relative to the valve seat 12 to control the flow of fuel gas from the inlet 9 to the outlet 9' of the fuel pressure reducer 6 as is explained in greater detail in the following.

[0078] The valve member 11 and the valve seat 12 separate the fuel pressure reducer 6 into an upstream part 26, connected to the inlet 9 of the fuel pressure reducer 6, and a downstream part 26', connected to outlet 9' of the fuel pressure reducer 6. According to the illustrated embodiments, the fuel pressure reducer 6 comprises a control volume 14 connected to the downstream part 26' of the fuel pressure reducer 6 and a diaphragm 13 comprising a surface forming a delimiting surface of the control volume 14. The diaphragm 13 may also be referred to as a membrane.

[0079] Moreover, the fuel pressure reducer 6 further comprises a spring member 15. The spring member 15 is operably connected to the diaphragm 13 and to the valve member 11. The spring member 15 is configured to bias the valve member 11 towards an open position relative to the valve seat 12. Such a biasing direction corresponds to a direction downwards in the schematic illustration of Fig. 2. A fluid connection between the upstream part 26 and the downstream part 26' of the fuel pressure reducer 6 is open via an orifice formed between the valve member 11 and the valve seat 12 when the valve member 11 is in the open position relative to the valve seat 12.

[0080] When a vehicle 2 comprising the engine 5 and the fuel gas supply arrangement 1 is activated for operation, the valve v1 may be controlled to the open state. In this manner, pressurized fuel gas can flow from the pressure tank 3 into the inlet 9 of the fuel pressure reducer 6 via the first conduit assembly c1 and from the upstream part 26 of the fuel pressure reducer 6 through the orifice formed between the valve member 11 and the valve seat 12 into the downstream part 26' of the fuel pressure reducer 6, and therefrom into the second conduit assembly c2 via the outlet 9' of the fuel pressure reducer 6. If the propulsion system 60 is deactivated, such as when the engine 5 is at standstill, no fuel gas is consumed by the propulsion system 60 of the vehicle 2, and therefore, the pressure in the downstream part 26' of the fuel pressure reducer 6 and the second conduit assembly c2 is increased.

[0081] The increased pressure is transferred to the control volume 14 which forces the diaphragm 13 to move in a direction which compresses the spring member 15 and moves the valve member 11 towards a closed state. In the schematic illustration of Fig. 2, such a direction corresponds to an upward direction. In the closed state, the valve member 11 abuts against the valve seat 12 which closes the fluid connection between the upstream part 26 and the downstream part 26' of the fuel pressure reducer 6 and thereby also between the inlet 9 and the outlet 9' of the fuel pressure reducer 6. In Fig. 2, the valve member 11 is illustrated in the closed position relative to the valve member 11.

[0082] According to the embodiments illustrated in Fig. 2, the fuel pressure reducer 6 is a so called balanced fuel pressure reducer 6 which means that the fuel pressure reducer 6 comprises a second control volume 16 fluidly connected to the downstream part 26' of the fuel pressure reducer 6. A portion of the valve member 11 is arranged in a cylindrical part of the second control volume 16 such that the portion of the valve member 11 is subjected to a current pressure in the downstream part 26' of the fuel pressure reducer 6. A pressure acting on the portion of the valve member 11 biases the valve member 11 towards the closed position. However, a surface area of the portion of the valve member 11 is smaller than the surface area of the diaphragm 13. Therefore, in total, the valve member 11 is moved towards the closed position when the pressure in the downstream part 26' of the fuel pressure reducer 6 increases above a set pressure and the spring member 15 becomes compressed.

[0083] As understood from the above described, the surface area of the diaphragm 13, the surface area of the portion of the valve member 11, and the stiffness/spring constant of the spring member 15 determines the set pressure of the fuel pressure reducer 6. The set pressure of the fuel pressure reducer 6 thus corresponds to a pressure level at the downstream part 26' of the fuel pressure reducer 6 at which the valve member 11 is moved to the closed position. Purely as an example, the set pressure of the fuel pressure reducer 6 may be within the range of 5 - 9 bar.

[0084] According to further embodiments, the fuel pressure reducer 6 may comprise a piston instead of the membrane 13, wherein the piston is operably connected to the valve member 11 and the control volume 14 to obtain the above described functionality.

[0085] During use, sealing surfaces of the valve member 11 and the valve seat 12 may be subjected to wear and tear, which may cause leakages of fuel gas past the valve member 11 and the valve seat 12 even though the valve member 11 is moved to the closed position relative to the valve seat 12. Such leakages will increase the pressure in the downstream part 26' of the fuel pressure reducer 6 and in the first conduit assembly c1 connected to the outlet 9' of the fuel pressure reducer 6. The increased pressure increases the contact force between the valve member 11 and the valve seat 12 due to the increased pressure acting on the diaphragm 13. Therefore, the fluid connection between the upstream part 26 and the downstream part 26' of the fuel pressure reducer 6 may become closed but at a higher pressure at the downstream part 26' of the fuel pressure reducer 6. The increased contact force obtained between the valve member 11 and the valve seat 12 may damage the valve member 11 and/or the valve seat 12.

[0086] The fuel gas supply arrangement 1 further comprises a pressure relief valve 7. The pressure relief valve 7 is configured to vent gas from the second conduit assembly c2 when the pressure in the second conduit assembly c2 exceeds a pressure limit. Purely as an example, the pressure limit may be around 12 bars. The pressure limit is set to a higher pressure than the set pressure of the fuel pressure reducer 6 and thus also higher than a normal operation pressure of the propulsion system 60 of the vehicle 2. The pressure relief valve 7 may also be referred to as a safety valve, a relief valve, a safety relief valve, a pressure safety valve (PSV), and an overflow valve.

[0087] The fuel gas supply arrangement 1 according to the illustrated embodiments further comprises a first pressure sensor s1 configured to provide pressure data representative of a current pressure in the first conduit assembly c1 and a second pressure sensor s2 provide pressure data representative of a current pressure in the second conduit assembly c2.

[0088] Moreover, according to the embodiments illustrated in Fig. 2, the fuel gas supply arrangement 1 comprises a low pressure valve 8. The low pressure valve 8 is controllable to a closed state, in which the low pressure valve 8 blocks flow of fuel gas between the outlet 9' of the fuel pressure reducer 6 and the propulsion system 60 of the vehicle 2, and an open state, in which the low pressure valve 8 allows flow of fuel gas between the outlet 9' of the fuel pressure reducer 6 and the propulsion system 60 of the vehicle 2 of the engine 5. The low pressure valve 8 may be controlled to the closed state upon deactivation of the propulsion system 60, of the engine 5 of the propulsion system 60, or the vehicle 2 comprising the propulsion system 60, and may be controlled to the open state upon activation of the propulsion system 60, the engine 5 of the propulsion system 60, or the vehicle 2 comprising the propulsion system 60.

[0089] According to the embodiments illustrated in Fig. 2, each of the first pressure sensor s1, the fuel pressure reducer 6, the pressure relief valve 7, the second pressure sensor s2, and the low pressure valve 8 is arranged in a so called gas panel 10. According to further embodiments, at least the fuel pressure reducer 6, and possibly also the pressure relief valve 7, may be arranged in the gas panel 10. The gas panel 10 comprises coolant channels 36' arranged in thermal contact with the fuel pressure reducer 6 and the pressure relief valve 7.

[0090] As explained above, the fuel pressure reducer 6 is configured to reduce the pressure supplied from the pressure tank 3 to the set pressure being lower that the pressure supplied from the pressure tank 3. The fuel pressure reducer 6 becomes cold due to the expansion of fuel gas inside the fuel pressure reducer 6. Therefore, coolant from the engine 5 is pumped through the coolant channels 36' via a conduit assembly 36 so as to heat the fuel pressure reducer 6 during operation thereof.

[0091] As illustrated in Fig. 2, the fuel gas supply arrangement 1 comprises a control arrangement 21. The control arrangement 21 is operably connected to the second pressure sensor s2. Moreover, according to the illustrated embodiments, the control arrangement 21 is also operably connected to the first pressure sensor s1, the valve v1, and the low pressure valve 8. However, according to further embodiments, the control arrangement 21, as referred to herein, may be operably connected to the second pressure sensor s2 only.

[0092] According to embodiments herein, the control arrangement 21 is configured to obtain pressure data at multiple consecutive occasions, wherein the pressure data is representative of a pressure in the second conduit assembly c2 during zero-flow conditions over the fuel pressure reducer 6. Moreover, the control arrangement 21 is configured to diagnose the operational performance of the fuel pressure reducer 6 by analysing the obtained pressure data. Thereby, a control arrangement 21 is provided capable of performing a reliable diagnosis of the operational performance of the fuel pressure reducer in a simple and efficient manner. This is because the obtained pressure data, being representative of a pressure in the second conduit assembly during zero-flow conditions over the fuel pressure reducer 6 at the multiple consecutive occasions, can indicate if the pressure in the second conduit assembly c2 is developing over time during zero-flow conditions over the fuel pressure reducer 6. Such development of the pressure in the second conduit assembly c2 can give a clear indication of the operational performance of the fuel pressure reducer 6 and if the valve member 11 or the valve seat 12 of the fuel pressure reducer 6 has been subjected to wear and tear.

[0093] Moreover, by diagnosing the operational performance of the fuel pressure reducer 6 by analysing the obtained pressure data, the diagnosis can indicate how the pressure in the second conduit assembly c2 is likely to develop to form the basis of an accurate recommendation when to schedule a workshop visit for servicing or replacing the fuel pressure reducer 6, as is explained in greater detail below.

[0094] According to the illustrated embodiments, the control arrangement 21 is configured to obtain the pressure data by inputting data from the second pressure sensor s2 at the multiple consecutive occasions. The multiple consecutive occasions, as referred to herein, may comprise at least two occasions, or at least five occasions. Moreover, the multiple consecutive occasions may comprise consecutive occasions occurring at different operational instances of the vehicle 2. In other words, the control arrangement 21 may be configured to obtain the pressure data at multiple consecutive occasions such that at least a number of the multiple consecutive occasions occur at different operational instances of the vehicle 2.

[0095] One operational instance of the vehicle 2 may comprise one or more of an activation of the vehicle 2, the propulsion system 60, an engine 5 of the propulsion system 60, the fuel gas supply arrangement 1, a cranking of an engine 5 of the propulsion system 60, an operation phase of an engine 5 of the propulsion system 60, a shutting down of an engine 5 of the propulsion system 60, and a deactivation of one or more of the vehicle 2, the propulsion system 60, the engine 5, and the fuel gas supply arrangement 1.

[0096] The wording zero-flow condition, as used herein, means that there is no flow of fuel gas, or at least substantially no flow of fuel gas, past the valve member 11 and the valve seat 12 of the fuel pressure reducer 6.

[0097] Moreover, the multiple consecutive occasions may comprise consecutive occasions occurring during a respective time period between an activation of the vehicle 2 and activation of the propulsion system 60. In other words, the control arrangement 21 may be configured to obtain the pressure data at multiple consecutive occasions such that at least a number of the multiple consecutive occasions occur during a respective time period between an activation of the vehicle 2 and activation of the propulsion system 60.

[0098] According to these embodiments, the control arrangement 21 may be configured to control the valve v1 to the open state upon activation of the vehicle 2. As explained above, when the valve v1 is controlled to the open state, pressurized fuel gas can flow from the pressure tank 3 into the inlet 9 of the fuel pressure reducer 6 via the first conduit assembly c1 and from the upstream part 26 of the fuel pressure reducer 6 through the orifice formed between the valve member 11 and the valve seat 12 into the downstream part 26' of the fuel pressure reducer 6, and therefrom into the second conduit assembly c2 via the outlet 9' of the fuel pressure reducer 6. If the engine 5 is at standstill, no fuel gas is consumed by the propulsion system 60 of the vehicle 2, and therefore, the pressure in the downstream part 26' of the fuel pressure reducer 6 and the second conduit assembly c2 is increased.

[0099] When the pressure in the downstream part 26' of the fuel pressure reducer 6 and the second conduit assembly c2 reaches the set pressure, the valve member 11 is moved to the closed position relative to the valve seat 12, as explained above, and a zero-flow condition is obtained over the fuel pressure reducer 6 when the pressure in the downstream part 26' of the fuel pressure reducer 6 and the second conduit assembly c2 reaches the set pressure.

[0100] Thus, according to these embodiments, the control arrangement 21 may be configured to obtain the pressure data shortly after the valve v1 has been controlled to the open state. As indicated in Fig. 2, according to the illustrated embodiments, the control arrangement 21 is configured to control the valve v1 between the open and closed states.

[0101] By obtaining pressure data at multiple consecutive occasions during these types of instances, the operational performance of the fuel pressure reducer 6 can be diagnosed in a simple, efficient, and reliable manner. The obtained pressure data obtained at the multiple consecutive occasions may be saved into a memory, such as a memory comprised in the control arrangement 21. The pressure data may be represented by a list of pressure values obtained at the multiple consecutive occasions.

[0102] According to some embodiments, the control arrangement 21 may be configured to estimate a remaining operational lifespan of the fuel pressure reducer 6 based on the obtained pressure data. The estimation may be performed by comparing the pressure data obtained at the multiple consecutive occasions to identify whether the pressure in the second conduit assembly c2 is developing over time as well as analysing the rate of change of the pressure in the second conduit assembly c2 between the multiple consecutive occasions.

[0103] Moreover, according to some embodiments, the control arrangement 21 may be configured to estimate at least one of a remaining time, a remaining travel distance, a remaining number of operational instances, and a remaining amount of fuel supplied to the propulsion system 60 of the vehicle 2 before a predetermined pressure is reached in the second conduit assembly c2. Such an estimation may be based on saved historic travel data of the vehicle 2 and saved historic fuel consumption of the vehicle 2.

[0104] The predetermined pressure may be set to a level below the pressure limit of the pressure relief valve 7 and above the set pressure of the fuel pressure reducer 6. In other words, according to such embodiments, the pressure limit of the pressure relief valve 7 is higher than the predetermined pressure.

[0105] The control arrangement 21 may be configured to set a fault indicator based on the diagnosis of the operational performance of the fuel pressure reducer 6. In more detail, the fault indicator may be indicative of at least one of a remaining time, a remaining travel distance, a remaining number of operational instances, and a remaining amount of fuel supplied to the propulsion system 60 of the vehicle 2 before the predetermined pressure is reached in the second conduit assembly c2. The fault indicator may be outputted in a driver environment 55 of a vehicle 2 comprising the fuel gas supply arrangement 1, for example on a display arranged in the driver environment 55. As an alternative, the fault indicator may be outputted to an external device, such as to an external diagnostics tool, or the like. A driver environment 55 of the vehicle 2 is schematically indicated in Fig. 1.

[0106] According to some embodiments, the control arrangement 21 is configured to schedule a workshop visit based on the estimated remaining operational lifespan of the fuel pressure reducer 6. According to such embodiments, the scheduled workshop visit may be outputted in a driver environment 55 of a vehicle 2 comprising the fuel gas supply arrangement 1, for example on a display arranged in the driver environment 55. As an alternative, the scheduled workshop visit may be outputted to an external device, such as to an external diagnostics tool, or the like.

[0107] Moreover, according to some embodiments, the control arrangement 21 is configured to set a fault indicator for the pressure relief valve 7 if the data indicates that the pressure in the second conduit assembly c2 is within a predetermined pressure range, below the pressure limit, at a number of consecutive occasions without any further increase in pressure. This is because in such situations, i.e., situations in which the data indicates that the pressure in the second conduit assembly c2 is within the predetermined pressure range at a number of consecutive occasions without any further increase in pressure, can indicate that the pressure relief valve 7 is malfunctioning and opens at too low pressures in the second conduit assembly c2, i.e., at pressures below the set pressure limit of the pressure relief valve 7.

[0108] The fault indicator for the pressure relief valve 7 may be outputted in a driver environment 55 of a vehicle 2 comprising the fuel gas supply arrangement 1, for example on a display arranged in the driver environment 55. As an alternative, the fault indicator for the pressure relief valve 7 may be outputted to an external device, such as to an external diagnostics tool, or the like.

[0109] According to the embodiments illustrated in Fig. 2, the second pressure sensor s2 is positioned between the outlet 9' of the fuel pressure reducer 6 and the low pressure valve 8. However, according to further embodiments, the second pressure sensor s2 may be arranged downstream of the low pressure valve 8, i.e., between the low pressure valve 8 and the propulsion system 60 of the vehicle 2. According to such embodiments, the control arrangement 21 may be configured to control the low pressure valve 8 to the open state before obtaining pressure data at the multiple consecutive occasions.

[0110] Fig. 3 schematically illustrates the propulsion system 60 of the vehicle 2 illustrated in Fig. 1, and a fuel gas supply arrangement 1' according to some further embodiments. The fuel gas supply arrangement 1' according to the embodiments illustrated in Fig. 3 comprises the same features, functions, and advantages, as the fuel gas supply arrangement 1 explained with reference to Fig. 2, with some differences pointed out below. The like features, functions, and advantages are not further explained herein. As indicated in Fig. 1, the vehicle 2 may comprise a fuel gas supply arrangement 1' according to the embodiments illustrated in Fig. 3.

[0111] According to the embodiments illustrated in Fig. 3, the fuel gas supply arrangement 1' comprises a so called "non-balanced" fuel pressure reducer 6'. Also in these embodiments, the fuel pressure reducer 6' may be referred to as a pressure regulator, fuel gas pressure regulator, or simply a regulator.

[0112] The fuel pressure reducer 6' of the fuel gas supply arrangement 1' according to the embodiments illustrated in Fig. 3 lacks the second control volume and a portion of the valve member 11' instead faces the upstream part 26 of the fuel pressure reducer 6'. Apart from this, the fuel pressure reducer 6' according to the embodiments illustrated in Fig. 3 operates in the same manner as the fuel pressure reducer 6 explained with reference to Fig. 2.

[0113] However, since the fuel pressure reducer 6' according to the embodiments illustrated in Fig. 3 lacks the second control volume and the portion of the valve member 11' instead faces the upstream part 26 of the fuel pressure reducer 6', the outlet pressure, i.e., the pressure in the downstream part 26' of the fuel pressure reducer 6', and consequently also the pressure in the second conduit assembly c2, is influenced by changes in the inlet pressure, i.e., is influenced by the pressure in the upstream part 26 of the fuel pressure reducer 6'.

[0114] Therefore, according to these embodiments, the control arrangement 21 is configured to obtain pressure data at the multiple consecutive occasions being representative of a pressure in the first conduit assembly c1 during zero-flow conditions over the fuel pressure reducer 6', and is configured to diagnose the operational performance of the fuel pressure reducer 6' by analysing this pressure data together with the pressure data representative of the pressure in the second conduit assembly c2. According to these embodiments, the control arrangement 21 may be configured to compare the pressure data of the second conduit assembly c2 with the pressure data of the first conduit assembly c1 and may adjust the diagnosis based on a difference between the pressure data of the first conduit assembly c1 and the pressure data of the second conduit assembly c2.

[0115] Also in the embodiments illustrated in Fig. 2, the control arrangement 21 may be configured to obtain pressure data at the multiple consecutive occasions being representative of a pressure in the first conduit assembly c1 during zero-flow conditions over the fuel pressure reducer 6. In these embodiments, the obtained pressure data of the first conduit assembly c1 may be used for statistics and/or for adapting or adjusting the diagnosis of the fuel pressure reducer 6.

[0116] According to the embodiments illustrated in Fig. 2 and Fig. 3, the fuel gas supply arrangement 1, 1' comprises one fuel pressure reducer 6, 6' only. However, according to further embodiments, the fuel gas supply arrangement 1, 1' may comprise two fuel pressure reducers arranged in series, i.e., in which an outlet of a first fuel pressure reducer is connected to an inlet of a second fuel pressure reducer. Such arrangements of two fuel pressure reducers can be advantageous when the pressure tank 3 of the fuel gas supply arrangement 1, 1' is configured to accommodate fuel gas at high pressures, such as in hydrogen systems where the pressure in the pressure tank 3 can be around 700 bar. By arranging two fuel pressure reducers in series, the pressure can be reduced in two steps which reduces the pressure difference between an upstream part and a downstream part of each fuel pressure reducer.

[0117] In embodiments in which the fuel gas supply arrangement 1, 1' comprises two fuel pressure reducers arranged in series, one of the fuel pressure reducers may be a balanced fuel pressure reducer, such as the fuel pressure reducer 6 explained with reference to Fig. 2, and the other of the fuel pressure reducers may be an unbalanced fuel pressure reducer, such as the fuel pressure reducer 6' explained with reference to Fig. 3. Typically, the first fuel pressure reducer according to the above is a balanced fuel pressure reducer 6 and the second fuel pressure reducer is an unbalanced fuel pressure reducer 6'.

[0118] In embodiments in which the fuel gas supply arrangement 1, 1' comprises a first and a second fuel pressure reducer arranged in series, the control arrangement 21 may be configured to obtain pressure data at multiple consecutive occasions, wherein the pressure data is representative of a pressure downstream the first fuel pressure reducer and upstream of the second fuel pressure reducer during zero-flow conditions over the fuel pressure reducers. The control arrangement 21 may be configured to diagnose the operational performance of the first fuel pressure reducer by analysing this pressure data. Moreover, the control arrangement 21 may be configured to obtain pressure data upstream of the first fuel pressure reducer and may adjust or adapt the diagnosis based on this pressure data.

[0119] Moreover, in embodiments in which the fuel gas supply arrangement 1, 1' comprises a first and a second fuel pressure reducer arranged in series, the control arrangement 21 may be configured to obtain pressure data at multiple consecutive occasions, wherein the pressure data is representative of a pressure downstream the second fuel pressure reducer during zero-flow conditions over the fuel pressure reducers. The control arrangement 21 may be configured to diagnose the operational performance of the second fuel pressure reducer by analysing this pressure data. Also in these embodiments, the control arrangement 21 may be configured to obtain pressure data upstream of the second fuel pressure reducer and may adjust or adapt the diagnosis based on this pressure data.

[0120] Fig. 4 schematically illustrates a method 100 of diagnosing a fuel gas supply arrangement of a vehicle. The fuel gas supply arrangement may be a fuel gas supply arrangement 1 according to the embodiments illustrated in Fig. 2, or a fuel gas supply arrangement 1' according to the embodiments illustrated in Fig. 3, and the vehicle may be a vehicle 2 according to the embodiments illustrated in Fig. 1. Therefore, below, simultaneous reference is made to Fig. 1 - Fig. 4, if not indicated otherwise.

[0121] The method is a method 100 of diagnosing a fuel gas supply arrangement 1, 1', wherein the fuel gas supply arrangement 1, 1' is configured to supply fuel gas to a propulsion system 60 of the vehicle 2. The fuel gas supply arrangement 1, 1' comprises a pressure tank 3 configured to store the fuel gas, a fuel pressure reducer 6, 6', a first conduit assembly c1 connecting an inlet 9 of the fuel pressure reducer 6, 6' to the pressure tank 3, and a second conduit assembly c2 connecting an outlet 9' of the fuel pressure reducer 6, 6' to the propulsion system 60. The method 100 comprises the steps of:

• obtaining 110 pressure data at multiple consecutive occasions, wherein the pressure data is representative of a pressure in the second conduit assembly c2 during zero-flow conditions over the fuel pressure reducer 6, 6', and
• diagnosing 130 an operational performance of the fuel pressure reducer 6, 6' by analysing the obtained pressure data.

[0122] The step of obtaining 110 the pressure data at the multiple consecutive occasions may be performed using input from a pressure sensor s2 configured to sense a current pressure in the second conduit assembly c2.

[0123] Moreover, as indicated in Fig. 4, the method 100 may comprise the step of:

• saving 120 the pressure data obtained at the multiple consecutive occasions into a memory.

[0124] The step of diagnosing 130 the operational performance of the fuel pressure reducer 6, 6' may thus be performed by analysing the data stored on the memory. The memory may be a memory of the control arrangement 21 or of an external device or system.

[0125] Moreover, as indicated in Fig. 4, the method 100 may comprise the step of:

• outputting 141 data representative of the diagnosis of the operational performance of the fuel pressure reducer 6, 6' in a driver environment 55 of a vehicle 2 comprising the fuel gas supply arrangement 1, 1', and/or to an external device, such as to an external diagnostics tool.

[0126] The data representative of the diagnosis of the operational performance of the fuel pressure reducer 6, 6' may be outputted in the form of a fault indicator for the fuel pressure reducer 6, 6'.

[0127] As indicated in Fig. 4, the step of obtaining 110 the pressure data may comprise:

• obtaining 112 the pressure data at multiple consecutive occasions such that at least a number of the multiple consecutive occasions occur at different operational instances of the vehicle 2.

[0128] According to some embodiments, the step of obtaining 112 the pressure data may be performed such that each of the multiple consecutive occasions occur at an individual operational instance of the vehicle 2.

[0129] Moreover, as indicated in Fig. 4, the step of obtaining 110 the pressure data may comprise:

• obtaining 114 the pressure data at multiple consecutive occasions such that at least a number of the multiple consecutive occasions occur during a respective time period between an activation of the vehicle 2 and activation of the propulsion system 60.

[0130] According to some embodiments, the step of obtaining 114 the pressure data may be performed such that each of the multiple consecutive occasions occur during a time period between an activation of the vehicle 2 and activation of the propulsion system 60.

[0131] Furthermore, as indicated in Fig. 4, the step of diagnosing 130 the operational performance of the fuel pressure reducer 6, 6' may comprise:

• estimating 131 a remaining operational lifespan of the fuel pressure reducer 6, 6' based on the obtained pressure data.

[0132] Moreover, as indicated in Fig. 4, the method 100 may comprise the step of:

• outputting 143 data representative of the remaining operational lifespan of the fuel pressure reducer 6, 6' in a driver environment 55 of a vehicle 2 comprising the fuel gas supply arrangement 1, 1', and/or to an external device, such as to an external diagnostics tool.

[0133] As indicated in Fig. 4, the step of estimating 131 the remaining operational lifespan may comprise:

• estimating 132 at least one of a remaining time, a remaining travel distance, a remaining number of operational instances, and a remaining amount of fuel supplied to the propulsion system 60 of the vehicle 2 before a predetermined pressure is reached in the second conduit assembly c2.

[0134] Moreover, as indicated in Fig. 4, the method 100 may comprise the step of:

• outputting 145 data representative of the at least one of the remaining time, the remaining travel distance, the remaining number of operational instances, and the remaining amount of fuel supplied to the propulsion system 60 of the vehicle 2 in a driver environment 55 of a vehicle 2 comprising the fuel gas supply arrangement 1, 1', and/or to an external device, such as to an external diagnostics tool.

[0135] According to some embodiments, the fuel gas supply arrangement 1, 1' comprises a pressure relief valve 7 configured to vent gas from the second conduit assembly c2 when the pressure in the second conduit assembly c2 exceeds a pressure limit. According to such embodiments, the pressure limit may be higher than the predetermined pressure.

[0136] According to the embodiments illustrated in Fig. 4, the method 100 comprises:

• scheduling 135 a workshop visit based on the estimated remaining operational lifespan of the fuel pressure reducer 6, 6'.

[0137] Moreover, as indicated in Fig. 4, the method 100 may comprise the step of:

• outputting 147 data representative of the scheduled workshop visit of the fuel pressure reducer 6, 6' in a driver environment 55 of a vehicle 2 comprising the fuel gas supply arrangement 1, 1', and/or to an external device, such as to an external diagnostics tool.

[0138] According to some embodiments, the fuel gas supply arrangement 1, 1' comprises a pressure relief valve 7 configured to vent gas from the second conduit assembly c2 when the pressure in the second conduit assembly c2 exceeds a pressure limit, and wherein the method 100 comprises:

• setting 137 a fault indicator for the pressure relief valve 7 if the data indicates that the pressure in the second conduit assembly c2 is within a predetermined pressure range, below the pressure limit, at a number of consecutive occasions without any further increase in pressure.

[0139] Moreover, as indicated in Fig. 4, the method 100 may comprise the step of:

• outputting 149 data representative of the fault indicator for the pressure relief valve 7 in a driver environment 55 of a vehicle 2 comprising the fuel gas supply arrangement 1, 1', and/or to an external device, such as to an external diagnostics tool.

[0140] Any of the herein described fault indicators may be represented by a specific fault code. The fault indicator/ fault indicators may be saved into a memory, and/or may be outputted to, and/or on, another device such as an external diagnostics tool, and/or may be outputted in a driver environment 55 of a vehicle 2.

[0141] It will be appreciated that the various embodiments described for the method 100 are all combinable with the control arrangement 21 as described herein. That is, the control arrangement 21 may be configured to perform any one of the method steps 110, 112, 114, 120, 130, 131, 132, 135, 137, 141, 143, 145, 147, and 149 of the method 100.

[0142] Fig. 5 illustrates a computer-readable medium 200 comprising instructions which, when executed by a computer, cause the computer to carry out the method 100 according to some embodiments of the present disclosure. According to some embodiments, the computer-readable medium 200 comprises a computer program comprising instructions which, when the program is executed by a computer, cause the computer to carry out the method 100 according to some embodiments. The computer may be comprised in the control arrangement 21.

[0143] One skilled in the art will appreciate that the method 100 of diagnosing a fuel gas supply arrangement 1, 1' of a vehicle 2 may be implemented by programmed instructions. These programmed instructions are typically constituted by a computer program, which, when it is executed in the control arrangement 21, ensures that the control arrangement 21 carries out the desired control, such as the method steps 110, 112, 114, 120, 130, 131, 132, 135, 137, 141, 143, 145, 147, and 149 described herein. The computer program is usually part of a computer program product which comprises a suitable digital storage medium on which the computer program is stored, such as the computer-readable medium 200 illustrated in Fig. 5. In other words, the computer program product may be a computer readable medium 200 and the computer program may be stored in the computer readable medium 200.

[0144] The control arrangement 21 may comprise a computer which may take the form of substantially any suitable type of hardware or hardware/firmware device implemented using processing circuity such as, but not limited to, a processor, Central Processing Unit (CPU), a controller, an arithmetic logic unit (ALU), a digital signal processor, an Application Specific Integrated Circuit (ASIC), a circuit for digital signal processing (digital signal processor, DSP), a microcomputer, a field programmable gate array (FPGA), a System-on-Chip (SoC), a programmable logic unit, a microprocessor, an application-specific integrated circuit, or any other device capable of electronically performing operations in a defined manner, or other processing logic that may interpret and execute instructions. The herein utilised expression "computer" may represent a processing circuitry comprising a plurality of processing circuits, such as, e.g., any, some or all of the ones mentioned above.

[0145] The control arrangement 21 may further comprise a memory unit, wherein the computer may be connected to the memory unit, which may provide the computer with, for example, stored program code and/or stored data which the computer may need to enable it to do calculations. The computer may also be adapted to store partial or final results of calculations in the memory unit. The memory unit may comprise a physical device utilised to store data or programs, i.e., sequences of instructions, on a temporary or permanent basis. According to some embodiments, the memory unit may comprise integrated circuits comprising silicon-based transistors. The memory unit may comprise e.g. a memory card, a flash memory, a USB memory, a hard disc, or another similar volatile or non-volatile storage unit for storing data such as e.g. ROM (Read-Only Memory), PROM (Programmable Read-Only Memory), EPROM (Erasable PROM), EEPROM (Electrically Erasable PROM), etc. in different embodiments.

[0146] The control arrangement 21 is connected to components of the vehicle 2, and/or the fuel gas supply arrangement 1, 1', for receiving and/or sending input and output signals. These input and output signals may comprise waveforms, pulses, or other attributes which the input signal receiving devices can detect as information and which can be converted to signals processable by the control arrangement 21. These signals may then be supplied to the computer. One or more output signal sending devices may be arranged to convert calculation results from the computer to output signals for conveying to other parts of the vehicle's control system and/or the component or components for which the signals are intended. Each of the connections to the respective components of the vehicle 2, and/or the fuel gas supply arrangement 1, 1', for receiving and sending input and output signals may take the form of one or more from among a cable, a data bus, e.g. a CAN (controller area network) bus, a MOST (media orientated systems transport) bus or some other bus configuration, or a wireless connection.

[0147] In the embodiments illustrated, the fuel gas supply arrangement 1, 1' of the vehicle 2 comprises a control arrangement 21 but might alternatively be implemented wholly or partly in two or more control arrangements, two or more control arrangements, or two or more control units.

[0148] Control systems in modern vehicles generally comprise a communication bus system consisting of one or more communication buses for connecting a number of electronic control units (ECUs), or controllers, to various components on board the vehicle. Such a control system may comprise a large number of control units and taking care of a specific function may be shared between two or more of them. Vehicles and engines of the type here concerned are therefore often provided with significantly more control arrangements than depicted in Fig. 2 and Fig. 3, as one skilled in the art will surely appreciate.

[0149] The computer-readable medium 200 may be provided for instance in the form of a data carrier carrying computer program code for performing at least some of the method steps 110, 112, 114, 120, 130, 131, 132, 135, 137, 141, 143, 145, 147, and 149 according to some embodiments of the method 100 when being loaded into one or more computers of the control arrangement 21. The data carrier may be, e.g. a CD ROM disc, as is illustrated in Fig. 5, or a ROM (read-only memory), a PROM (programable read-only memory), an EPROM (erasable PROM), a flash memory, an EEPROM (electrically erasable PROM), a hard disc, a memory stick, an optical storage device, a magnetic storage device or any other appropriate medium such as a disk or tape that may hold machine readable data in a non-transitory manner. Accordingly, in some embodiments, the computer-readable medium 200 may be a non-transitory computer-readable medium, such as a tangible electronic, magnetic, optical, infrared, electromagnetic, and/or semiconductor system, apparatus, and/or device. The computer-readable medium 200 may furthermore be provided as computer program code on a server and may be downloaded to the control arrangement 21 remotely, e.g., over an Internet or an intranet connection, or via other wired or wireless communication systems.

[0150] It is to be understood that the foregoing is illustrative of various example embodiments and that the invention is defined only by the appended independent claims. A person skilled in the art will realize that the example embodiments may be modified, and that different features of the example embodiments may be combined to create embodiments other than those described herein, without departing from the scope of the present invention, as defined by the appended independent claims.

[0151] As used herein, the term "comprising" or "comprises" is open-ended, and includes one or more stated features, elements, steps, components, or functions but does not preclude the presence or addition of one or more other features, elements, steps, components, functions, or groups thereof.

Claims

1. A method (100) of diagnosing a fuel gas supply arrangement (1, 1'), wherein the fuel gas supply arrangement (1, 1') is configured to supply fuel gas to a propulsion system (60) of a vehicle (2), the fuel gas supply arrangement (1, 1') comprising:

- a pressure tank (3) configured to store the fuel gas,

- a fuel pressure reducer (6, 6'),

- a first conduit assembly (c1) connecting an inlet (9) of the fuel pressure reducer (6, 6') to the pressure tank (3), and

- a second conduit assembly (c2) connecting an outlet (9') of the fuel pressure reducer (6, 6') to the propulsion system (60),

and wherein the method (100) comprises the steps of:

- obtaining (110) pressure data at multiple consecutive occasions, wherein the pressure data is representative of a pressure in the second conduit assembly (c2) during zero-flow conditions over the fuel pressure reducer (6, 6'), and

- diagnosing (130) an operational performance of the fuel pressure reducer (6, 6') by analysing the obtained pressure data.

2. The method (100) according to claim 1, wherein the step of obtaining (110) the pressure data comprises:

- obtaining (112) the pressure data at multiple consecutive occasions such that at least a number of the multiple consecutive occasions occur at different operational instances of the vehicle (2).

3. The method (100) according to claim 1 or 2, wherein the step of obtaining (110) the pressure data comprises:

- obtaining (114) the pressure data at multiple consecutive occasions such that at least a number of the multiple consecutive occasions occur during a respective time period between an activation of the vehicle (2) and activation of the propulsion system (60).

4. The method (100) according to any one of the preceding claims, wherein the step of diagnosing (130) the operational performance of the fuel pressure reducer (6, 6') comprises:

- estimating (131) a remaining operational lifespan of the fuel pressure reducer (6, 6') based on the obtained pressure data.

5. The method (100) according to claim 4, wherein the step of estimating (131) the remaining operational lifespan comprises:

- estimating (132) at least one of a remaining time, a remaining travel distance, a remaining number of operational instances, and a remaining amount of fuel supplied to the propulsion system (60) before a predetermined pressure is reached in the second conduit assembly (c2).

6. The method (100) according to claim 5, wherein the fuel gas supply arrangement (1, 1') comprises a pressure relief valve (7) configured to vent gas from the second conduit assembly (c2) when the pressure in the second conduit assembly (c2) exceeds a pressure limit, wherein the pressure limit is higher than the predetermined pressure.

7. The method (100) according to any one of the claims 4 - 6, wherein the method (100) comprises:

- scheduling (135) a workshop visit based on the estimated remaining operational lifespan of the fuel pressure reducer (6, 6').

8. The method (100) according to any one of the preceding claims, wherein the fuel gas supply arrangement (1, 1') comprises a pressure relief valve (7) configured to vent gas from the second conduit assembly (c2) when the pressure in the second conduit assembly (c2) exceeds a pressure limit, and wherein the method (100) comprises:

- setting (137) a fault indicator for the pressure relief valve (7) if the data indicates that the pressure in the second conduit assembly (c2) is within a predetermined pressure range, below the pressure limit, at a number of consecutive occasions without any further increase in pressure.

9. A control arrangement (21) for a fuel gas supply arrangement (1, 1'), wherein the fuel gas supply arrangement (1, 1') is configured to supply fuel gas to a propulsion system (60) of a vehicle (2), the fuel gas supply arrangement (1, 1') comprising:

- a pressure tank (3) configured to store the fuel gas,

- a fuel pressure reducer (6, 6'),

- a first conduit assembly (c1) connecting an inlet (9) of the fuel pressure reducer (6, 6') to the pressure tank (3),

- a second conduit assembly (c2) connecting an outlet (9') of the fuel pressure reducer (6, 6') to the propulsion system (60), and

- a control arrangement (21),

wherein the control arrangement (21) is configured to:

- obtain pressure data at multiple consecutive occasions, wherein the pressure data is representative of a pressure in the second conduit assembly (c2) during zero-flow conditions over the fuel pressure reducer (6, 6'), and

- diagnose an operational performance of the fuel pressure reducer (6, 6') by analysing the obtained pressure data.

10. A computer program comprising instructions to cause the control arrangement (21) according to claim 9 to execute the steps of the method (100) according to any one of the claims 1-8.

11. A computer-readable medium (200) having stored thereon the computer program of claim 10.

12. A fuel gas supply arrangement (1, 1') for a vehicle (2), wherein the fuel gas supply arrangement (1, 1') is configured to supply fuel gas to a propulsion system (60) of the vehicle (2), the fuel gas supply arrangement (1, 1') comprises:

- a pressure tank (3) configured to store the fuel gas,

- a fuel pressure reducer (6, 6'),

- a first conduit assembly (c1) connecting an inlet (9) of the fuel pressure reducer (6, 6') to the pressure tank (3),

- a second conduit assembly (c2) connecting an outlet (9') of the fuel pressure reducer (6, 6') to the propulsion system (60), and

- a control arrangement (21) according to claim 9.

13. A vehicle (2) comprising a propulsion system (60), wherein the vehicle (2) comprises a fuel gas supply arrangement (1, 1') according to claim 12, and wherein the fuel gas supply arrangement (1, 1') is configured to supply fuel gas to the propulsion system (60) of the vehicle (2).

14. The vehicle (2) according to claim 13, wherein the vehicle (2) is a heavy road vehicle, such as a truck or a bus.

Drawing