Method and control device for determining the state of a fluid reservoir

Abstract

A method and control device (228) for determining the status of a primary fluid reservoir (127) or one or more secondary fluid reservoirs (129), each of the fluid reservoirs (127, 129) being arranged to contain a fluid or mixture of fluids available in liquefied form and vaporized form and connected to a second pressurized fluid conduit arrangement (226). The control device (228) determines a pressure drop (Δp) associated with fluid flow through the second pressurized fluid conduit arrangement (226). When the pressure drop (Δp) exceeds a threshold value, the control device (228) blocks fluid flow from one (127, 129) of the fluid reservoirs (127, 129) to the second pressurized fluid conduit arrangement (226). Based on a subsequently determined pressure drop (Δp), the control device (228) determines whether the one (127, 129) of the primary fluid reservoir and the secondary fluid reservoirs (127, 129) is devoid of liquefied fluid.

Description

Technical Field

[0001] This disclosure relates to the technical field of determining the condition of a fuel storage tank containing a fluid or mixture of fluids available in liquefied and evaporated forms. Background Technology

[0002] Today, vehicles powered by methane are produced. Generally, fuel supply systems for methane are available with two different alternatives. According to the first alternative, methane is supplied as compressed natural gas (CNG). According to the second alternative, methane is supplied as liquefied natural gas (LNG). LNG has a higher density than CNG and therefore provides a longer driving range for vehicles. Generally, in vehicles, such as trucks or tractors, LNG is stored in one or more cryogenic containers or tanks. Typically, two tanks are provided for LNG, one on each lateral side of the vehicle. Each of the two tanks holds or contains both liquid and vapor phases of LNG and is typically maintained at a pressure of 10 to 16 bar, but the pressure can also be lower than 10 bar or higher than 16 bar. In addition to methane, LNG may also include small amounts of another gas or other gases. Methane can be replaced by some other gas. The vapor phase of LNG, or what may be called the pressure head, is generally used to expel LNG from the tank and supply it to the vehicle's engine. When the tank is filled with LNG, a filling hose is connected to the tank's inlet to supply the liquid phase of LNG. To allow fuel to be pushed into the storage tank, it may be necessary to reduce the pressure before filling. To ventilate the tank, a manually operated valve device can be manually opened by the user or driver to reduce or equalize the tank pressure. A venting hose can be connected to the tank's venting connector, which in turn connects to the manually operated valve device to guide the vapor phase of LNG away from the tank and back to the filling station. When two or more tanks are provided in a vehicle, the tanks can be fluidly connected to the same venting connector via their opened, manually operated valve devices. Summary of the Invention

[0003] When filling two or more storage tanks, such as those in a vehicle, with liquid LNG, manually operated valves are opened by the operator or driver to ventilate the tanks and maintain the pressure at permissible filling levels. Generally, the manually operated valves are connected to a single, identical vent connector to which the vent hose is attached. Therefore, when the manually operated valves are open, the tanks are vapor-connected to each other. The manually operated valves should be closed after the filling process. The inventors of this invention have discovered that the manually operated valves sometimes remain open after the filling process and therefore remain open when the vehicle is driven. The inventors of this invention have also discovered that vapor communication between the tanks makes it difficult to determine the state of the tanks.

[0004] The purpose of this invention is to provide a solution that alleviates or resolves the drawbacks and problems of conventional solutions.

[0005] The above and other objectives are achieved through the subject matter of the independent claims. Further advantageous embodiments of the invention can be found in the dependent claims.

[0006] According to a first aspect of the invention, a method is provided for determining the state of a primary fluid storage tank or one or more secondary fluid storage tanks. Each of the primary fluid storage tank and the secondary fluid storage tanks is arranged to contain a fluid or a mixture of fluids available in liquefied and evaporated forms, wherein...

[0007] The primary fluid storage tank and the secondary fluid storage tank are part of the pressurization section of the fluid system, wherein

[0008] Each of the primary fluid storage tank and the secondary fluid storage tank has a first air inlet line, the first air inlet line having an inlet located inside the fluid storage tank, and the first air inlet line being part of the pressurization section, wherein

[0009] The inlet of the first intake line is arranged to primarily receive the liquid of the fluid, wherein

[0010] The primary fluid storage tank and the secondary fluid storage tank are in vapor communication with each other via a first pressurized fluid conduit device, allowing the vapor of the fluid to travel from one of the primary fluid storage tank and the secondary fluid storage tank to the other. The first pressurized fluid conduit device is part of the pressurization section of the fluid system.

[0011] The first intake line is arranged to be fluidly connected to a second pressurized fluid conduit assembly and is arranged to provide fluid flow from the main fluid tank and the secondary fluid tank to the second pressurized fluid conduit assembly, which is part of the pressurized section of the fluid system, and wherein...

[0012] The fluid system includes one or more sensors for determining one or more pressures of the fluid in the pressurized section. The method includes:

[0013] • By using the sensor, one or more pressure drops associated with the fluid flow through the second pressurized fluid conduit device are determined;

[0014] • When the pressure drop exceeds the threshold, the fluid flow from one of the main fluid tank and the secondary fluid tank to the second pressurized fluid conduit device is blocked, while the fluid flow from the other of the main fluid tank and the secondary fluid tank to the second pressurized fluid conduit device continues;

[0015] • When fluid flow from one of the main fluid tank and the secondary fluid tank to the second pressurized fluid conduit is blocked, while fluid flow from the other of the main fluid tank and the secondary fluid tank to the second pressurized fluid conduit continues, a sensor is used to determine the pressure drop associated with the fluid flow through the second pressurized fluid conduit. The method further includes:

[0016] • When the fluid flow from one of the main fluid tank and the secondary fluid tank to the second pressurized fluid conduit is blocked, if the pressure drop returns to a value below the threshold, it is determined that one of the main fluid tank and the secondary fluid tank has no liquefied fluid, or the method further includes:

[0017] • When the fluid flow from one of the main fluid tank and the secondary fluid tank to the second pressurized fluid conduit is blocked, if the pressure drop remains above the threshold, the fluid flow from the other of the main fluid tank and the secondary fluid tank to the second pressurized fluid conduit is blocked, while the fluid flow from the one of the main fluid tank and the secondary fluid tank with the previously blocked fluid flow to the second pressurized fluid conduit is allowed.

[0018] • When the fluid flow from one of the main fluid tanks and the secondary fluid tanks to the second pressurized fluid conduit is blocked, while the fluid flow from the one of the main fluid tanks and the secondary fluid tanks with the previously blocked fluid flow to the second pressurized fluid conduit is permitted, the pressure drop associated with the fluid flow through the second pressurized fluid conduit is determined by using a sensor.

[0019] • When the fluid flow from the other of the primary fluid tank and the secondary fluid tank to the second pressurized fluid conduit is blocked, if the pressure drop remains above the threshold, it is determined that there is no liquefied fluid in the primary fluid tank and the secondary fluid tank.

[0020] • When the fluid flow from the other of the primary fluid tank and the secondary fluid tank to the second pressurized fluid conduit is blocked, if the pressure drop returns to a value below the threshold, it is determined that the other of the primary fluid tank and the secondary fluid tank has no liquefied fluid.

[0021] The pressure drop exceeding the threshold (e.g., due to a rapid increase in pressure drop in the fluid in the second pressurized fluid conduit) occurs when a fluid tank without liquefied fluid begins to draw in or draw in evaporating fluid through the inlet of the first inlet line, and thus draws in more evaporating fluid from another fluid tank via the first pressurized fluid conduit, which provides vapor communication between the primary and secondary fluid tanks. As a result, the pressure drop can exceed the threshold. In some systems, a rapid increase in pressure drop should be avoided and addressed when it occurs, for example, when it involves a vehicle engine. One response to counteract this rapid increase in pressure drop could be to block the fluid flow from the fluid tank without liquefied fluid, thereby stabilizing the pressure drop or reducing the rate of pressure drop. An advantage of the method according to the first aspect is that blocking the fluid flow from the fluid tank without liquefied fluid is part of the claimed method, and when determined, the fluid flow from the determined empty fluid tank may already be blocked.

[0022] In this specification, determining that any of the storage tanks contains no liquefied fuel includes determining that the tank is at least substantially free of liquefied fuel. That is, the liquid level is at least below a level that would be considered to indicate that the tank is empty.

[0023] An advantage of the method according to the first aspect is that it provides a procedure that accurately determines the state of a fluid storage tank in an efficient manner. The state of the fluid storage tank can be, for example, "no liquefied fluid" or "liquefied fluid present." In some fluid storage tanks, a level sensor is present, which measures the level of the liquefied fluid. However, such a level sensor may not accurately indicate the level of the liquefied fluid in the fluid storage tank, for example, when the vehicle that may carry the fluid storage tank is going downhill or uphill. For example, when the vehicle is traveling downhill, the level sensor may show a relevant amount of liquefied fluid in the fluid storage tank, even though the inlet of the first air intake line is not in contact with the liquefied fluid.

[0024] By employing the method according to the first aspect, the user or operator is not required to close one or more manual valve devices that should be open during the filling procedure after filling the primary and secondary fluid tanks and when, for example, driving a vehicle equipped with primary and secondary fluid tanks, because the innovative method can determine whether the tanks are empty even if the manual valve devices remain open. This simplifies the filling procedure. Since the method according to the first aspect assumes that the manual valve devices remain open, erroneous indications from the level sensors can be ignored, thereby preventing the user or driver from operating the vehicle's control system incorrectly.

[0025] Each of the sensors mentioned above and below for determining one or more pressures of the fluid in the pressurized section may be a sensor arranged to determine one or more pressures of the fluid in the second pressurized fluid conduit assembly.

[0026] According to an advantageous embodiment of the method of the first aspect, each of the primary fluid tank and the secondary fluid tank includes a level sensor for determining the height of the liquefied fluid within the fluid tank. A first step of blocking fluid flow from one of the primary and secondary fluid tanks to the second pressurized fluid conduit device when the pressure drop exceeds a threshold includes blocking fluid flow from one of the primary and secondary fluid tanks (relative to the height of the liquefied fluid inside the other primary and secondary fluid tanks, which has the lowest height of the liquefied fluid determined by the level sensor) to the second pressurized fluid conduit device, while fluid flow from the other primary and secondary fluid tanks continues. An advantage of this embodiment is that it further improves the procedure for determining the state of the fluid tanks because, according to this embodiment of the method, it is assumed that the fluid tank showing the lowest height of the liquefied fluid is empty. Alternatively, fluid flow from one of the primary fluid tank and the secondary fluid tank (with respect to the height of the liquefied fluid inside the other primary fluid tank and the secondary fluid tank, which has the highest height of the liquefied fluid determined by the level sensor) to the second pressurized fluid conduit assembly is blocked, while fluid flow from the other primary fluid tank and the secondary fluid tank continues.

[0027] According to another advantageous embodiment of the method of the first aspect, the method includes comparing a determined pressure drop with a threshold. The advantage of this embodiment is that it further improves the procedure for determining the state of a fluid storage tank.

[0028] According to another advantageous embodiment of the method of the first aspect, the sensor includes a pressure sensor for measuring the pressure of the fluid in the pressurized section, wherein the step of determining the pressure drop associated with the fluid flow through the second pressurized fluid conduit assembly includes measuring the pressure drop using the pressure sensor. An advantage of this embodiment is that it further improves the procedure for determining the state of the fluid tank. The sensor may include a pressure sensor for measuring the pressure of the fluid in the second pressurized fluid conduit assembly.

[0029] According to another advantageous embodiment of the method of the first aspect, the threshold is a predetermined threshold. The advantage of this embodiment is that it further improves the procedure for determining the state of a fluid storage tank.

[0030] According to another advantageous embodiment of the method of the first aspect, the fluid comprises fuel. The advantage of this embodiment is that it improves the procedure for determining the state of the fluid storage tank.

[0031] According to an advantageous embodiment of the method of the first aspect, the fluid comprises liquefied natural gas (LNG), such as methane. LNG may be present or available in liquid and / or vapor form. An advantage of this embodiment is that it improves the procedure for determining the condition of LNG storage tanks. In addition to methane, LNG may also include small amounts of another gas or other gases.

[0032] According to a second aspect of the invention, the aforementioned and other objectives are achieved by a computer program comprising instructions that, when executed by a computer, cause the computer to perform the method according to any of the embodiments disclosed above or below. The advantages of the computer program according to the second aspect correspond to the advantages mentioned above or below of the methods according to the first aspect and its embodiments.

[0033] According to a third aspect of the invention, the aforementioned and other objectives are achieved by a computer-readable medium comprising instructions that, when executed by a computer, cause the computer to perform the method according to any of the embodiments disclosed above or below. The advantages of the computer-readable medium according to the third aspect correspond to the advantages mentioned above or below of the methods according to the first aspect and its embodiments.

[0034] According to one aspect of the invention, the computer program and computer-readable medium mentioned above are configured to implement the methods described herein and their embodiments.

[0035] According to a fourth aspect of the invention, the above and other objectives are achieved by a control device for determining the state of a primary fluid tank or one or more secondary fluid tanks, each of the primary fluid tank and the secondary fluid tanks being arranged to contain a fluid or a mixture of fluids available in liquefied and evaporated forms, wherein

[0036] The primary fluid storage tank and the secondary fluid storage tank are part of the pressurization section of the fluid system, wherein

[0037] Each of the primary fluid storage tank and the secondary fluid storage tank has a first air inlet line, the first air inlet line having an inlet located inside the fluid storage tank, and the first air inlet line being part of the pressurization section, wherein

[0038] The inlet of the first intake line is arranged to primarily receive the liquid of the fluid, wherein

[0039] The primary fluid tank and the secondary fluid tank are arranged in vapor communication with a ventilation connector via a first pressurized fluid conduit assembly, allowing vapor of the fluid to travel from one of the primary fluid tank and the secondary fluid tank to the other. The first pressurized fluid conduit assembly is part of the pressurization section of the fluid system. A first inlet line is arranged to be fluidly connected to a second pressurized fluid conduit assembly and is configured to provide fluid flow from the primary fluid tank and the secondary fluid tank to the second pressurized fluid conduit assembly, which is also part of the pressurization section of the fluid system.

[0040] The fluid system includes one or more sensors for determining one or more pressures of the fluid in the pressurized section, wherein the control device is configured to:

[0041] By using sensors to determine one or more pressure drops associated with the fluid flow through the second pressurized fluid conduit assembly,

[0042] When the pressure drop exceeds a threshold, the fluid flow from one of the main fluid tank and the secondary fluid tank to the second pressurized fluid conduit is blocked, while the fluid flow from the other of the main fluid tank and the secondary fluid tank to the second pressurized fluid conduit continues.

[0043] When the fluid flow from one of the primary fluid tank and the secondary fluid tank to the second pressurized fluid conduit is blocked, if the pressure drop returns to a value below a threshold, it is determined that one of the primary fluid tank and the secondary fluid tank is substantially devoid of liquefied fluid.

[0044] When the fluid flow from one of the main fluid tank and the secondary fluid tank to the second pressurized fluid conduit is blocked, if the pressure drop remains above the threshold, the fluid flow from the other of the main fluid tank and the secondary fluid tank to the second pressurized fluid conduit is blocked, while the fluid flow from the one of the main fluid tank and the secondary fluid tank with the previously blocked fluid flow to the second pressurized fluid conduit is permitted.

[0045] When the fluid flow from the primary fluid tank and the other of the secondary fluid tank to the second pressurized fluid conduit is blocked, if the pressure drop remains above the threshold, it is determined that the primary fluid tank and the secondary fluid tank are substantially devoid of liquefied fluid, and

[0046] When the fluid flow from the other of the primary fluid tank and the secondary fluid tank to the second pressurized fluid conduit is blocked, if the pressure drop returns to a value below the threshold, it is determined that the other of the primary fluid tank and the secondary fluid tank is substantially without liquefied fluid.

[0047] The advantages of the control device according to the fourth aspect correspond to the advantages mentioned above or below of the method according to the first aspect and its embodiments.

[0048] According to an advantageous embodiment of the control device of the fourth aspect, the control device is configured to compare a determined voltage drop with a threshold.

[0049] According to a fifth aspect of the invention, the above and other objectives are achieved by a fluid system including a pressurizing section, said pressurizing section comprising...

[0050] A main fluid storage tank, the main fluid storage tank being arranged to contain a fluid or a mixture of fluids available in liquefied and evaporated forms.

[0051] One or more secondary fluid storage tanks are arranged to contain a fluid or a mixture of fluids available in liquefied and evaporated forms, wherein each of the primary fluid storage tank and the secondary fluid storage tanks has a first inlet line having an inlet located inside the fluid storage tank, the first inlet line being part of the pressurization section, wherein the inlet of the first inlet line is arranged to primarily receive liquid from the fluid.

[0052] A first pressurized fluid conduit is arranged to fluidly connect the primary fluid tank and the secondary fluid tank via a ventilated connector, thereby providing vapor communication between the primary and secondary fluid tanks, allowing vapor of the fluid to travel from one of the primary and secondary fluid tanks to the other.

[0053] A second pressurized fluid conduit assembly is arranged to be fluidly connected to the first inlet line, wherein the first inlet line is arranged to provide fluid flow from the main fluid tank and the secondary fluid tank to the second pressurized fluid conduit assembly.

[0054] The fluid system includes one or more sensors for determining one or more pressures of the fluid in the pressurized section, and the fluid system includes a control device according to any of the embodiments mentioned above or below.

[0055] The advantages of the fluid system according to the fifth aspect correspond to the advantages mentioned above or below of the method according to the first aspect and its embodiments.

[0056] According to an advantageous embodiment of the fluid system in the fifth aspect, the pressurization section of the fluid system includes a main valve device, wherein a first inlet line to the main fluid storage tank and a second pressurized fluid conduit device are arranged to be fluidly connected to each other via the main valve device, wherein the main valve device is arranged to block the fluid flow from the main fluid storage tank to the second pressurized fluid conduit device, and wherein a control device is configured to control the fluid from the main fluid storage tank by controlling the main valve device. An advantage of this embodiment is that it further improves the procedure for determining the state of the fluid storage tank.

[0057] According to another advantageous embodiment of the fluid system in the fifth aspect, the pressurization section of the fluid system includes a secondary valve device, wherein a first inlet line to the secondary fluid storage tank and a second pressurized fluid conduit device are arranged to be fluidly connected to each other via the secondary valve device, wherein the secondary valve device is arranged to block the fluid flow from the secondary fluid storage tank to the second pressurized fluid conduit device, and wherein a control device is configured to control the fluid from the secondary fluid storage tank by controlling the secondary valve device. An advantage of this embodiment is that it further improves the procedure for determining the state of the fluid storage tank.

[0058] According to another advantageous embodiment of the fluid system of the fifth aspect, each of the main fluid tank and the secondary fluid tank has a vent outlet arranged to be fluidly connected to the first pressurized fluid conduit device, wherein when the main fluid tank is installed, the inlet of the first air inlet line of the main fluid tank is located at a level below the vent outlet of the main fluid tank, and wherein when the secondary fluid tank is installed, the inlet of the first air inlet line of each secondary fluid tank is located at a level below the vent outlet of the secondary fluid tank.

[0059] According to another advantageous embodiment of the fluid system in the fifth aspect, the first pressurized fluid conduit device includes a main valve device and a secondary valve device, each of the main valve device and the secondary valve device being arranged to be manually operated, and wherein the vent outlet of the main fluid tank is fluidly connected to the vent outlet of the secondary fluid tank via the main valve device and the secondary valve device.

[0060] According to another advantageous embodiment of the fluid system of the fifth aspect, each of the main fluid tank and the secondary fluid tank has a second inlet line having an inlet located within the fluid tank, the second inlet line being part of the pressurization section, wherein the inlet of the second inlet line is arranged to receive vapor of the fluid, wherein the second inlet line is arranged to provide an evaporating fluid flow from the main fluid tank and the secondary fluid tank to the second pressurized fluid conduit device, wherein when the main fluid tank is installed, the inlet of the first inlet line of the main fluid tank is located at a horizontal level below the inlet of the second inlet line of the main fluid tank, and wherein when the secondary fluid tank is installed, the inlet of the first inlet line of the secondary fluid tank is located at a horizontal level below the inlet of the second inlet line of the secondary fluid tank.

[0061] According to an advantageous embodiment of the fluid system in the fifth aspect, the second inlet line of the main fluid tank and the second pressurized fluid conduit device are fluidly connected to each other via the main valve device, wherein the main valve device is arranged to block the fluid flow from the first inlet line and / or the second inlet line of the main fluid tank to the second pressurized fluid conduit device.

[0062] According to another advantageous embodiment of the fluid system in the fifth aspect, each of the primary fluid tank and the secondary fluid tank includes a level sensor for determining the height of the liquefied fluid within the fluid tank, wherein when the pressure drop exceeds a threshold, the control device is arranged to block the fluid flow from one of the primary fluid tank and the secondary fluid tank (relative to the height of the liquefied fluid inside the other primary fluid tank and the secondary fluid tank, which has the lowest height of the liquefied fluid determined by the level sensor) to the second pressurized fluid conduit assembly, while the fluid flow from the other primary fluid tank and the secondary fluid tank continues.

[0063] According to another advantageous embodiment of the fluid system in the fifth aspect, the sensor includes a pressure sensor for measuring the pressure of the fluid in the pressurized section, wherein the control device is configured to determine the pressure drop associated with the fluid flow through the second pressurized fluid conduit assembly by measuring the pressure drop using the pressure sensor. An advantage of this embodiment is that it further improves the procedure for determining the state of the fluid tank. The sensor may include a pressure sensor for measuring the pressure of the fluid in the second pressurized fluid conduit assembly.

[0064] According to another advantageous embodiment of the fluid system in the fifth aspect, each of the primary fluid tank and the secondary fluid tank is arranged to contain fluid in the form of fuel.

[0065] According to another advantageous embodiment of the fluid system in the fifth aspect, each of the primary fluid tank and the secondary fluid tank is arranged to contain a fluid in the form of liquefied natural gas (LNG), such as methane.

[0066] It should be understood that all embodiments described with respect to the method aspect of the present invention are also applicable to at least one of the control device aspect and the fluid system aspect of the present invention. Therefore, all embodiments described with respect to the method aspect of the present invention can be performed by a control device or a fluid system, the control device including a control unit or a controller. As mentioned above, the advantages of the control device and its embodiments, as well as the fluid system and its embodiments, correspond to the advantages mentioned above with respect to the method and its embodiments.

[0067] According to a sixth aspect of the invention, the above and other objectives are achieved by a vehicle comprising a fluid system according to any of the embodiments mentioned above or below. The vehicle may include a combustion engine, wherein a second pressurized fluid conduit is arranged fluidly connected to the combustion engine.

[0068] The aforementioned features and embodiments of the methods, computer programs, computer-readable media, control devices, fluid systems, and vehicles can be combined in various possible ways to provide further advantageous embodiments.

[0069] Further advantageous embodiments of the methods, computer programs, computer-readable media, control devices, fluid systems, and vehicles according to the invention, as well as further advantages of the embodiments of the invention, will become apparent from the dependent claims and the detailed description of the embodiments. Attached Figure Description

[0070] For illustrative purposes, embodiments of the invention will now be described in more detail by way of examples and with reference to the accompanying drawings, wherein similar reference numerals are used for similar parts, wherein:

[0071] Figure 1 This is a schematic diagram of a vehicle according to the sixth aspect of the present invention, in which embodiments of the invention may be implemented;

[0072] Figure 2 This is a schematic diagram illustrating an embodiment of a fluid system according to a fifth aspect of the present invention;

[0073] Figure 3 This is a flowchart illustrating an embodiment of the method according to the first aspect of the present invention;

[0074] Figure 4 This is a schematic diagram illustrating a voltage drop exceeding a threshold; and

[0075] Figure 5 This is a schematic diagram illustrating a control device according to a fourth aspect of the present invention. Detailed Implementation

[0076] refer to Figure 1 The diagram schematically illustrates a vehicle 100. The vehicle 100 may be referred to as a motor vehicle 100. The vehicle 100 may be a tractor or a truck, such as a heavy-duty truck, which may have a trailer. The vehicle 100 includes a powertrain 102 comprising a combustion engine 104, such as an internal combustion engine or other combustion engine, which is conventionally connected to a gearbox 108 via a first output shaft 106 and typically via a flywheel and a clutch 110. Generally, the combustion engine 104 includes cylinders. In addition to the powertrain 102 comprising the combustion engine 104, the vehicle 100 may also include one or more electric motors for driving the drive wheels 114, 116, 118, 120 of the vehicle 100, and thus may be, for example, a so-called hybrid vehicle.

[0077] The combustion engine 104 can be controlled by the engine's control system via control device 112. Similarly, the clutch 110 and transmission 108 can be controlled by the engine's control system via one or more control devices (not shown). The engine's control system and control device 112 and / or another control device can therefore be configured to control the combustion engine 104, clutch 110, transmission 108, and / or any other unit / device / entity of the vehicle 100. However, in Figure 1 The image shows only some of the units / devices / entities of vehicle 100.

[0078] Naturally, the powertrain 102 of vehicle 100 can be of different types, such as those with conventional automatic or manual transmissions, or those with hybrid powertrains. As mentioned above, the powertrain 102 can, for example, include one or more electric motors for driving the drive wheels 114, 116, 118, and 120 of vehicle 100, achieving so-called hybrid drive. Vehicle 100 may include four wheels 114, 116, 118, and 120 or more. As those skilled in the art will understand, the aforementioned motors can be arranged virtually anywhere, such as adjacent to one or more wheels 114, 116, 118, and 120, as long as torque is provided to one or more wheels 114, 116, 118, and 120. Vehicle 100 may include a propeller shaft 122 from transmission 108, which drives two wheels 114 and 116 via a central gear 124 (e.g., a conventional differential) and two drive shafts 126 and 128 of vehicle 100. Two drive shafts 126 and 128 are connected to a central gear 124. The vehicle 100 may include more than two drive wheels 114 and 116.

[0079] Vehicle 100 includes a primary fluid storage tank 127 and one or more secondary fluid storage tanks 129. In the illustrated embodiment, vehicle 100 includes one secondary fluid storage tank 129. However, vehicle 100 may include multiple, i.e., two or more secondary fluid storage tanks. The primary fluid storage tank 127 may be mounted on one lateral side of vehicle 100, while the secondary fluid storage tanks 129 may be mounted on another lateral side of vehicle 100. However, it should be understood that fluid storage tanks 127, 129 may be located at several other possible locations. The primary fluid storage tank 127 and secondary fluid storage tanks 129 may, for example, switch positions with each other. Furthermore, fluid storage tanks 127, 129 may, for example, be located on the same lateral side of the vehicle, for example, positioned front and rear in the longitudinal direction of vehicle 100, or at other locations. Each storage tank 127, 129 is arranged to contain or hold a fluid or a mixture of fluids. Each storage tank 127, 129 is arranged to contain or hold a fluid in liquefied and / or evaporated form. Therefore, it should be understood that the fluid may be a liquid or a vapor (gas) or a mixture thereof.

[0080] In the illustrated embodiment, the primary fluid storage tank 127 is a primary fuel storage tank 127, and each secondary fluid storage tank 129 is a secondary fuel storage tank 129. Therefore, each of the primary fluid storage tank 127 and the secondary fluid storage tanks 129 is arranged to contain a fluid in the form of fuel. Each fluid storage tank 127, 129 may be arranged to contain or hold a fluid in the form of liquefied natural gas (LNG), such as methane. Each fluid storage tank 127, 129 may be a cryogenic fluid storage tank and is arranged to store liquefied LNG at approximately -120°C or lower (e.g., approximately -160°C) inside the fluid storage tank 127, 129. When the liquefied LNG absorbs heat from the surrounding environment, the liquefied LNG evaporates, and the pressure of the LNG fluid increases. Preferably, the LNG is kept in liquid form in the fluid storage tanks 127, 129. Therefore, the fluid storage tanks 127, 129 are preferably thermally insulated. Each fluid storage tank 127, 129 may define a compartment for holding the fluid. Each fluid storage tank 127, 129 may include an inner container having the compartment and an outer container that closes or surrounds the inner container, wherein thermal insulation, such as a vacuum, may be provided between the inner container and the outer container. In addition to methane, LNG may also include small amounts of another gas or other gases. Other gases may be used instead of methane.

[0081] LNG can exist in liquid and / or vapor form. When liquid LNG is present in fluid storage tanks 127 and 129, a certain amount of evaporated LNG will also be present. The evaporated LNG, or gaseous or vaporous LNG, in fluid storage tanks 127 and 129 can be referred to as pressure head. Pressure head enables the liquid LNG to be pushed or forced from fluid storage tanks 127 and 129 to combustion engine 104. Therefore, combustion engine 104 can be supplied with fuel from the primary fluid storage tank 127 and the secondary fluid storage tank 129 connected to combustion engine 104. LNG is known to those skilled in the art and therefore will not be discussed in further detail.

[0082] refer to Figure 1 The vehicle 100 includes a fluid system 202, for example, in the form of a fuel system, which includes a pressurization section 204, wherein the pressurization section 204 includes a primary fluid storage tank 127 and a secondary fluid storage tank 129.

[0083] Vehicle 100 may include an exhaust aftertreatment system 130 for treating / purifying exhaust gases / emissions generated by combustion in the combustion chamber of combustion engine 104, which may also be referred to as an exhaust purification system. The exhaust aftertreatment system 130 may be controlled by an exhaust aftertreatment control device 132, which may communicate with a control device 112 or another device of the engine's control system.

[0084] refer to Figure 2An embodiment of a fluid system 202 according to a fifth aspect of the invention is schematically illustrated. The fluid system 202 can be applied to or installed in a vehicle 100. The fluid system 202 includes a pressurization section 204. The pressurization section 204 includes a primary fluid reservoir 127 arranged to contain a fluid available or present in liquefied and evaporated forms, or a mixture of fluids available in liquefied and evaporated forms. The pressurization section 204 includes one or more secondary fluid reservoirs 129 arranged to contain fluids available in liquefied and evaporated forms, or a mixture of fluids available in liquefied and evaporated forms. In the illustrated embodiment, only one secondary fluid reservoir 129 is provided, but the fluid system 202 may include multiple secondary fluid reservoirs 129, i.e., two or more secondary fluid reservoirs 129. In the illustrated embodiment, each of the primary fluid reservoir 127 and the secondary fluid reservoirs 129 may be arranged to contain fluid in the form of fuel. Advantageously, each of the primary fluid storage tank 127 and the secondary fluid storage tank 129 is arranged to contain a fluid, such as methane, in the form of liquefied natural gas (LNG). In the illustrated embodiment, each of the primary fluid storage tank 127 and the secondary fluid storage tank 129 is arranged to contain LNG, such as methane, in both liquefied and evaporated forms. The primary fluid storage tank 129 may be referred to as the first fluid storage tank 127, and the secondary fluid storage tank 129 may be referred to as the second fluid storage tank 129. Each fluid storage tank 127, 129 may be, for example, a container.

[0085] Each of the primary fluid storage tank 127 and the secondary fluid storage tank 129 has a first inlet line 206, 208. Each first inlet line 206, 208 has an inlet 210, 212 located inside the fluid storage tanks 127, 129. Each first inlet line 206, 208 is part of a pressurization section 204. The inlets 210, 212 of the first inlet lines 206, 208 are arranged to primarily receive, draw in, or extract liquid (e.g., liquefied LNG in the illustrated embodiment). Each of the first inlet lines 206, 208 may be a conduit. Each of the first inlet lines 206, 208 is arranged to transport the fluid.

[0086] The pressurization section 204 includes a first pressurized fluid conduit 214, which is arranged to fluidly connect a primary fluid tank 127 and a secondary fluid tank 129 via a vent connector 224, thereby providing vapor communication between the primary and secondary fluid tanks 127 and 129, allowing fluid vapor to travel from one of the primary and secondary fluid tanks 127 to the other, for example, between the primary and secondary fluid tanks 129. The first pressurized fluid conduit 214 is arranged to transport fluid.

[0087] The fact that two entities are fluidly connected to each other in the context of this disclosure means that the existence of a fluid connection between the two entities allows fluid to travel between them.

[0088] Each of the primary fluid storage tank 127 and the secondary fluid storage tank 129 may have vents 216, 218 arranged to be fluidly connected to the first pressurized fluid conduit assembly 214. When the primary fluid storage tank 127 is installed, the inlet 210 of the first air inlet line 206 of the primary fluid storage tank 127 is located horizontally below the vents 216 of the primary fluid storage tank 127. When the secondary fluid storage tanks 129 are installed, the inlet 212 of the first air inlet line 208 of each secondary fluid storage tank 129 is located horizontally below the vents 218 of the secondary fluid storage tank 129.

[0089] The first pressurized fluid conduit assembly 214 may include a main valve assembly 220 and a secondary valve assembly 222. Each of the main valve assembly 220 and the secondary valve assembly 222 may be arranged for manual operation. Since both the main fluid tank 127 and the secondary fluid tank 129 are fluidly connected to the vent connector 224, the vent outlet 216 of the main fluid tank 127 is fluidly connected to the vent outlet 218 of the secondary fluid tank 129 via the main valve assembly 220 and the secondary valve assembly 222. The first pressurized fluid conduit assembly 214 may include the vent connector 224 as mentioned above. The vent connector 224 may include a valve. The vent connector 224 may be fluidly connected to the main valve assembly 220 and the secondary valve assembly 222.

[0090] As mentioned above, when the primary fluid storage tank 127 and the secondary fluid storage tank 129 are installed in vehicle 100 to supply fluids such as fuel (e.g., LNG) to, for example, the engine 104 of vehicle 100, and when the primary fluid storage tank 127 and the secondary fluid storage tank 129 are filled with liquefied LNG at a filling station, the user or operator can manually open the main valve device 220 and the secondary valve device 222 to ventilate the primary fluid storage tank 127 and the secondary fluid storage tank 129 via the ventilation connector 224, and maintain the pressure of the primary fluid storage tank 127 and the secondary fluid storage tank 129 at a level that allows for filling of the primary fluid storage tank 127 and the secondary fluid storage tank 129 with liquefied fluid or LNG. Typically, the main valve device 220 and the secondary valve device 222 are manually opened before starting to fill the primary fluid storage tank 127 and the secondary fluid storage tank 129 with liquefied fluid or LNG.

[0091] Typically, during the filling process, manually operated main valve 220 and secondary valve 222, connected to the same vent connector 224, are opened, and vent hoses can be connected to vent connector 224 to guide the evaporated LNG leaving the primary fluid tank 127 and secondary fluid tank 129 back to the filling station. This reduces or balances the pressure of the fluid in the primary fluid tank 127 and secondary fluid tank 129, and / or maintains the pressure of the fluid in the primary fluid tank 127 and secondary fluid tank 129 at a sufficiently low level to facilitate filling the primary fluid tank 127 and secondary fluid tank 129 with liquefied fluid or LNG. Otherwise, the evaporated LNG in the secondary fluid tanks 127, 129 could prevent the filling of the primary fluid tank 127 and secondary fluid tank 129. When the main valve device 220 and the secondary valve device 222 are opened manually, the main fluid storage tank 127 and the secondary fluid storage tank 129 are in vapor communication with each other, that is, vapor can travel from one of the main fluid storage tank 127 and the secondary fluid storage tank 129 to the other of the main fluid storage tank 127 and the secondary fluid storage tank 129, for example, traveling between the main fluid storage tank 127 and the secondary fluid storage tank 129.

[0092] Typically, and according to user instructions, the manually operated main valve device 220 and secondary valve device 222, or at least one of them, should preferably be closed after the filling procedure. If both the manually operated main valve device 220 and secondary valve device 222 are instead kept open after filling and during the driving of vehicle 100, LNG in evaporative form can travel from one of the main fluid storage tank 127 and secondary fluid storage tank 129 to the other, for example, between the main fluid storage tank 127 and secondary fluid storage tank 129. Therefore, when the liquid level of one of the primary fluid storage tank 127 and the secondary fluid storage tank 129 becomes low enough that the inlets 210 and 212 of the relevant first air inlet lines 206 and 208 cannot absorb or receive liquefied fluid—that is, when the primary fluid storage tank 127 and the secondary fluid storage tank 129 are installed, the inlets 210 and 212 of the relevant first air inlet lines 206 and 208 are higher than the level of the liquefied fluid—the inlets 210 and 212 of the relevant first air inlet lines 206 and 208 will draw in or receive fluid in the form of evaporation, and more evaporated fluid will be drawn from the other 127 and 129 of the primary fluid storage tank 127 and the secondary fluid storage tank 129 into the substantially empty fluid storage tanks 127 and 129. This results in a rapid increase in pressure reduction of the fluid in the pressurization section 204 of the fluid system 202. This increased pressure reduction is undesirable because a certain pressure is required in the pressurization section 204. The pressurization section 204 of the fluid system should supply fluid at a sufficient pressure level, for example, to the engine 104 of the vehicle 100. A response to such a rapid increase in pressure drop in the fluid within the pressurization section 204 could be to shut off or block the fluid flow from the substantially empty fluid tanks 127, 129, namely the primary fluid tank 127 and the secondary fluid tank 129. Level sensors 248, 250, used to determine the height of the liquefied fluid inside the fluid tanks 127, 129, can indicate which of the primary and secondary fluid tanks 127, 129 is substantially empty. However, for several reasons (one of which is disclosed later), such level sensors 248, 250 may not accurately provide the level of the liquefied fluid in the primary and secondary fluid tanks 127 and 129. Furthermore, level sensors 248, 250 may not be adequately calibrated and are therefore unreliable.

[0093] For example, if at least one of the main valve device 220 and the secondary valve device 222, or the main valve device 220 and the secondary valve device 222, is changed to be closed when the vehicle 100 is driven, then the fluid reservoirs 127 and 129, which would initially be substantially empty, will not draw evaporating fluid from the other 127 and 129 of the main fluid reservoir 127 and the secondary fluid reservoir 129, and therefore the rapid increase in pressure drop of the fluid in the pressurization section 204 will not occur, and the pressure drop of the fluid in the pressurization section 204 will be maintained at an acceptable level or rate for delivering pressurized fluid to the engine 104 of the vehicle 100. However, due to embodiments of the invention, the user or driver can keep the manually operated main valve device 220 and the secondary valve device 222 open during driving, as disclosed in more detail below.

[0094] In the context of this disclosure, "substantially no liquefied fluid," such as "substantially no liquefied LNG," means that fluid storage tanks 127 and 129 are substantially empty, but a small amount of liquefied fluid / LNG may be present at the bottom of fluid storage tanks 127 and 129 that are not accessible from the inlets 210 and 212 of the first inlet lines 206 and 208; that is, an irrelevant amount of liquefied fluid / LNG may be present in fluid storage tanks 127 and 129. "No liquefied fluid / LNG" can be expressed as no liquid fluid / LNG or no relevant amount of liquefied fluid. Even in fluid storage tanks 127 and 129 where there is substantially no liquefied fluid / LNG, fluid / LNG in evaporated form may still be present.

[0095] Furthermore, the pressurization section 204 includes a second pressurized fluid conduit 226, which is arranged to be fluidly connected to the first intake lines 206, 208. The first intake lines 206, 208 are arranged to provide a fluid flow (primarily a liquefied fluid flow) from the primary fluid tank 127 and the secondary fluid tank 129 to the second pressurized fluid conduit 226. In the illustrated embodiment, when the fluid system 202 is associated with a vehicle 100 including a combustion engine 104, the second pressurized fluid conduit 226 is arranged to be fluidly connected to the combustion engine 104 to provide fuel in the form of LNG to the combustion engine 104. The second pressurized fluid conduit 226 is arranged to transport fluid.

[0096] Fluid system 202 includes a control device 228 for determining the state of primary fluid tank 127 or one or more secondary fluid tanks 129. The state of each tank 127, 129 can be "no liquefied fluid" or "liquefied fluid present". Control device 228 may be arranged to communicate with control device 112 or another device of the engine's control system. Control device 228 is disclosed in more detail below.

[0097] Fluid system 202 includes one or more sensors, such as a sensor 230, for determining one or more pressures p of the fluid in pressurized section 204. Each of the sensor 230 or multiple sensors 230 mentioned above and below for determining one or more pressures of the fluid in pressurized section 204 may be a sensor arranged to determine one or more pressures of the fluid in second pressurized fluid conduit assembly 226. Sensor 230 may include a pressure sensor for measuring the pressure p of the fluid in pressurized section 204. Sensor 230 may include a pressure sensor for measuring the pressure p of the fluid in second pressurized fluid conduit assembly 226. Control device 228 is configured to determine one or more pressure drops Δp associated with the fluid flow through second pressurized fluid conduit assembly 226 by using sensor 230. Pressure drop Δp may be a pressure reduction rate, for example, in bar per second. Sensor 230 may be located in pressurized section 204, for example in second pressurized fluid conduit assembly 226.

[0098] Control device 228 can be configured to determine the pressure drop Δp associated with the fluid flow through the second pressurized fluid conduit 226 by measuring the pressure drop Δp using a pressure sensor. The reason for determining the pressure drop Δp is disclosed below. Alternatively, another value of a pressure-related variable associated with the pressure of the fluid in the pressurized section 204 or the second pressurized fluid conduit 226 can be determined or measured, and the pressure of the fluid in the second pressurized fluid conduit 226 or the pressurized section 204 can be determined based on it. Sensor 230 can be part of regulator unit 231, which includes sensor 230 and regulator 233. Regulator 233 can disconnect pressurized section 204 from low-pressure fuel system 235, which is then fluidly connected or can be connected to engine 104 of vehicle 100. However, sensor 230 can be a separate unit separate from regulator unit 231.

[0099] The pressurization section 204 of the fluid system 202 includes a main valve assembly 232. A first inlet line 206 and a second pressurized fluid conduit assembly 226 of the main fluid reservoir 127 may be arranged to be fluidly connected to each other via the main valve assembly 232. The main valve assembly 232 may include an economizer. Economizers are known to those skilled in the art and are therefore not disclosed in further detail. The main valve assembly 232 may be arranged to block fluid flow from the main fluid reservoir 127 to the second pressurized fluid conduit assembly 226. The main valve assembly 232 may also be arranged to allow fluid flow from the main fluid reservoir 127 to the second pressurized fluid conduit assembly 226. A control device 228 may be configured to control the fluid from the main fluid reservoir 127 by controlling the main valve assembly 232.

[0100] Furthermore, the pressurization section 204 of the fluid system 202 may include a main automatic shut-off valve 234. The main automatic shut-off valve 234 may be included in the main valve assembly 232. Therefore, the main valve assembly 232 may include the main automatic shut-off valve 234. The first air inlet line 206 and the second pressurized fluid conduit assembly 226 of the main fluid reservoir 127 may be arranged to be fluidly connected to each other via the main automatic shut-off valve 234. The control device 228 may be configured to close the main automatic shut-off valve 234 when the vehicle 100 is shut down or de-energized, or when the vehicle 100 experiences an accident. The automatic shut-off valve 234 for the vehicle 100 is known to those skilled in the art and therefore will not be disclosed in further detail. The control device 228 may be configured to control the fluid from the main fluid reservoir 127 by controlling the main automatic shut-off valve 234.

[0101] The pressurization section 204 of the fluid system 202 includes a secondary valve device 236. A first inlet line 208 and a second pressurized fluid conduit device 226 of the secondary fluid reservoir 129 may be arranged to be fluidly connected to each other via the secondary valve device 236. The secondary valve device 236 may include an economizer. The secondary valve device 236 may be arranged to block fluid flow from the secondary fluid reservoir 129 to the second pressurized fluid conduit device 226. Alternatively, the secondary valve device 236 may be arranged to allow fluid flow from the secondary fluid reservoir 129 to the second pressurized fluid conduit device 226. A control device 228 may be configured to control the fluid from the secondary fluid reservoir 129 by controlling the secondary valve device 236.

[0102] Furthermore, the pressurization section 204 of the fluid system 202 may include a secondary automatic shut-off valve 238. The secondary automatic shut-off valve 238 may be included in the secondary valve assembly 236. Therefore, the secondary valve assembly 236 may include the secondary automatic shut-off valve 238. The first air inlet line 206 and the second pressurized fluid conduit assembly 226 of the secondary fluid storage tank 129 may be arranged to be fluidly connected to each other via the secondary automatic shut-off valve 238. The control device 228 may be arranged to close the secondary automatic shut-off valve 238 when the vehicle 100 is shut down or de-energized, or when the vehicle 100 experiences an accident. The control device 228 may be configured to control the fluid from the secondary fluid storage tank 129 by controlling the secondary automatic shut-off valve 238.

[0103] Each of the main valve device 232 and the secondary valve device 236 can be arranged to control the supply of liquefied fluid to the second pressurized fluid conduit device 226 when the pressure of the fluid in the pressurized section 204 is below a certain level (e.g., 10 bar). Each of the main valve device 232 and the secondary valve device 236 can be arranged to control the supply of evaporated fluid to the second pressurized fluid conduit device 226 when the pressure of the fluid in the pressurized section 204 is above a certain level (e.g., 10 bar). This ensures that the pressure of the fluid in the main fluid tank 127 and the secondary fluid tank 129 does not drop too rapidly. Instead of the 10 bar level, another suitable level can be selected. How the valve devices can achieve this type of switching between the supply of liquefied fluid and evaporated fluid, for example by means of springs, is known to those skilled in the art and therefore will not be discussed further in detail.

[0104] Each of the primary fluid storage tank 127 and the secondary fluid storage tank 129 has a second inlet line 240, 242. Each of the second inlet lines 240, 242 has an inlet 244, 246 located inside the fluid storage tanks 127, 129. Each of the second inlet lines 240, 242 may be a conduit. Each of the second inlet lines 240, 242 is arranged to transport fluid. The second inlet lines 240, 242 are part of the pressurization section 204 of the fluid system 202. The inlets 244, 246 of the second inlet lines 240, 242 are arranged to receive or draw in vapor from the fluid. The second inlet lines 240, 242 are arranged to provide an evaporating fluid flow from the primary fluid storage tank 127 and the secondary fluid storage tank 129 to the second pressurized fluid conduit assembly 226. When the main fluid storage tank 127 is installed, the inlet 210 of the first air inlet line 206 of the main fluid storage tank 127 is located horizontally below the inlet 244 of the second air inlet line 240 of the main fluid storage tank 127. When the secondary fluid storage tank 129 is installed, the inlet 212 of the first air inlet line 208 of the secondary fluid storage tank 129 is located horizontally below the inlet 246 of the second air inlet line 242 of the secondary fluid storage tank 129.

[0105] The second air inlet line 240 and the second pressurized fluid conduit 226 of the main fluid storage tank 127 can be fluidly connected to each other via the main valve device 232. Therefore, according to this embodiment, the main valve device 232 and / or the main automatic shut-off valve 234 are arranged to block fluid flow from the first air inlet line 206 and / or the second air inlet line 240 of the main fluid storage tank 127 to the second pressurized fluid conduit 226. The main valve device 232 and / or the main automatic shut-off valve 234 can also be arranged to allow fluid flow from the first air inlet line 206 and / or the second air inlet line 240 of the main fluid storage tank 127 to the second pressurized fluid conduit 226.

[0106] The second inlet line 242 and the second pressurized fluid conduit 226 of the secondary fluid storage tank 129 can be fluidly connected to each other via a secondary valve device 236. Therefore, according to this embodiment, the secondary valve device 236 and / or the secondary automatic shut-off valve 238 are arranged to block fluid flow from the first inlet line 208 and / or the second inlet line 242 of the secondary fluid storage tank 129 to the second pressurized fluid conduit 226. The secondary valve device 236 and / or the secondary automatic shut-off valve 238 can also be arranged to allow fluid flow from the first inlet line 208 and / or the second inlet line 242 of the secondary fluid storage tank 129 to the second pressurized fluid conduit 226.

[0107] As mentioned above, the fluid system 202 includes a control device 228 for determining the state of the primary fluid tank 127 or one or more secondary fluid tanks 129. For the illustrated embodiment, where the fluid may correspond to LNG (e.g., methane), the control device 228 is configured to:

[0108] By using sensor 230, one or more pressure drops Δp associated with the fluid flow through the second pressurized fluid conduit assembly 226 are determined.

[0109] When the pressure drop Δp exceeds a threshold, the fluid flow from one of the main fluid storage tank 127 and the secondary fluid storage tank 129 to the second pressurized fluid conduit 226 is blocked, for example, through the main valve device 232, the main automatic shut-off valve 234, the secondary valve device 236, or the secondary automatic shut-off valve 238, while the fluid flow from the other of the main fluid storage tank 127 and the secondary fluid storage tank 129 to the second pressurized fluid conduit 226 continues.

[0110] When the fluid flow from one of the primary fluid storage tanks 127 and 129 to the second pressurized fluid conduit assembly 226 is blocked, if the pressure drop Δp returns to a value below a threshold, it is determined that there is essentially no liquefied fluid in one of the primary fluid storage tanks 127 and 129.

[0111] When the fluid flow from one of the main fluid tanks 127 and 129 to the second pressurized fluid conduit 226 is blocked, if the pressure drop Δp remains above a threshold, the fluid flow from the other of the main fluid tanks 127 and 129 to the second pressurized fluid conduit 226 is blocked, for example, by the main valve device 232, the main automatic shut-off valve 234, the secondary valve device 236, or the secondary automatic shut-off valve 238, while allowing the fluid flow from the one of the main fluid tanks 127 and 129 with the previously blocked fluid flow to the second pressurized fluid conduit 226.

[0112] When the fluid flow from one of the primary fluid storage tanks 127 and 129 to the second pressurized fluid conduit assembly 226 is blocked, if the pressure drop Δp remains above a threshold, it is determined that both the primary fluid storage tank 127 and the secondary fluid storage tank 129 are substantially devoid of liquefied fluid.

[0113] When the fluid flow from one of the primary fluid storage tanks 127 and 129 to the second pressurized fluid conduit assembly 226 is blocked, if the pressure drop Δp returns to a value below the threshold, it is determined that there is essentially no liquefied fluid in the other of the primary fluid storage tanks 127 and 129.

[0114] The threshold may be a predetermined threshold. The control device 228 may be configured to compare a determined voltage drop Δp with the threshold.

[0115] Each of the primary fluid storage tank 127 and the secondary fluid storage tank 129 may include level sensors 248 and 250 for determining the level of liquefied fluid inside the fluid storage tanks 127 and 129. However, such level sensors 248 and 250 may not accurately indicate the level of liquefied fluid in the primary fluid storage tank 127 and the secondary fluid storage tank 129, for example, when the vehicle 100 that may carry the primary fluid storage tank 127 and the secondary fluid storage tank 129 is going downhill or uphill. For example, when the vehicle 100 is traveling downhill, level sensors 248 and 250 may indicate the presence of a relevant amount of liquefied fluid in the primary fluid storage tank 127 or the secondary fluid storage tank 129, even though the inlets 210 and 212 of the first air intake lines 206 and 208 are not in contact with the liquefied fluid. When the pressure drop Δp exceeds a threshold, the control device 228 can be configured to block the fluid flow from one of the primary fluid tank 127 and the secondary fluid tank 129 (relative to the height of the liquefied fluid inside the other 127 and the secondary fluid tank 129, which has the lowest height of the liquefied fluid determined by the level sensors 248 and 250) to the second pressurized fluid conduit device 226, while the fluid flow from the other 127 and the secondary fluid tank 129 continues.

[0116] refer to Figure 2The control device 228 may include a pressure drop determination unit 260 for determining the pressure drop Δp based on input from sensor 230. The control device 228 may include a valve control unit 262 for controlling the main valve device 232, the main automatic shut-off valve 234, the secondary valve device 236, and the secondary automatic shut-off valve 238, i.e., by opening or closing these valves. The control device 228 may include a tank status determination unit 264 for determining the status of the main fluid tank 127 or the secondary fluid tank 129.

[0117] refer to Figure 3 The illustration shows an embodiment of a method according to a first aspect of the invention for determining the state of a primary fluid storage tank 127 or one or more secondary fluid storage tanks 129, each of which is arranged to contain a fluid or mixture of fluids available or present in liquefied and evaporated forms. For example, the state of the primary fluid storage tank 127 or the secondary fluid storage tank 129 may be substantially without liquefied fluid / LNG or with liquefied fluid / LNG. As disclosed above, the primary fluid storage tank 127 and the secondary fluid storage tank 129 may be included in a fluid system 202.

[0118] The method according to the illustrated embodiment includes the following steps:

[0119] • One or more pressure drops Δp are determined using sensors, relating to the fluid flow through the second pressurized fluid conduit. The pressure drop Δp can be given as a pressure reduction rate. The pressure drop Δp can be related to fuel consumption rate, for example, in units of kg / h or kg / 100km;

[0120] • Compare the determined voltage drop Δp with a threshold 302, which can substantially correspond to Figure 4 The inflection point shown in the graph illustrates the pressure of the fluid in the second pressurized fluid conduit assembly 226 over time. The threshold value can be a predetermined value. Figure 4 In this context, pressure is placed on the y-axis and time on the x-axis. Figure 4 In the diagram, to the left of the vertical dashed line, most of the fluid is in liquefied form, and to the right of the vertical dashed line, the fluid is increasingly evaporating. Line a can illustrate the result of the method performed according to the first aspect of the invention. Line b can illustrate when the fluid flow from the empty fluid storage tank is not blocked;

[0121] • When the pressure drop Δp exceeds the threshold, block 303 the fluid flow from one of the main fluid tank and the secondary fluid tank to the second pressurized fluid conduit device, while the fluid flow from the other of the main fluid tank and the secondary fluid tank to the second pressurized fluid conduit device continues;

[0122] • When the fluid flow from one of the main fluid tank and the secondary fluid tank to the second pressurized fluid conduit is blocked, while the fluid flow from the other of the main fluid tank and the secondary fluid tank to the second pressurized fluid conduit continues, the pressure drop Δp associated with the fluid flow through the second pressurized fluid conduit is determined by using a sensor 304.

[0123] • When the fluid flow from one of the main fluid tank and the secondary fluid tank to the second pressurized fluid conduit is blocked, and when the fluid flow from the other of the main fluid tank and the secondary fluid tank to the second pressurized fluid conduit continues, if the pressure drop Δp returns to a value below a threshold, then it is determined that one of the main fluid tank and the secondary fluid tank, i.e., the fluid tank with the currently blocked fluid flow to the second pressurized fluid conduit, is substantially devoid of liquefied fluid.

[0124] • When the fluid flow from one of the main fluid tanks and the secondary fluid tanks to the second pressurized fluid conduit is blocked and when the fluid flow from the other of the main fluid tanks and the secondary fluid tanks to the second pressurized fluid conduit continues, if the pressure drop Δp remains above a threshold, then block 306 the fluid flow from the other of the main fluid tanks and the secondary fluid tanks to the second pressurized fluid conduit, while allowing the fluid flow from the one of the main fluid tanks and the secondary fluid tanks with the previously blocked fluid flow to the second pressurized fluid conduit;

[0125] • When the fluid flow from one of the main fluid tanks and the secondary fluid tanks to the second pressurized fluid conduit is blocked, while the fluid flow from the one of the main fluid tanks and the secondary fluid tanks with the previously blocked fluid flow to the second pressurized fluid conduit is permitted, the pressure drop Δp associated with the fluid flow through the second pressurized fluid conduit is determined by using a sensor 307.

[0126] • When the fluid flow from one of the main fluid tanks and the secondary fluid tanks to the second pressurized fluid conduit is blocked and when the fluid flow from the one of the main fluid tanks and the secondary fluid tanks with the previously blocked fluid flow to the second pressurized fluid conduit is permitted, if the pressure drop Δp remains above a threshold, it is determined that neither the main fluid tank nor the secondary fluid tank has substantially any liquefied fluid.

[0127] • When the fluid flow from one of the main fluid tanks and the secondary fluid tanks to the second pressurized fluid conduit is blocked, and when the fluid flow from the one of the main fluid tanks and the secondary fluid tanks with the previously blocked fluid flow to the second pressurized fluid conduit is permitted, if the pressure drop Δp returns to a value below a threshold, then it is determined that the other of the main fluid tanks and the secondary fluid tanks, i.e., the fluid tank with the currently blocked fluid flow to the second pressurized fluid conduit, is substantially without liquefied fluid.

[0128] It should be understood that all steps in determining the voltage drop Δp can be followed by a step of comparing the voltage drop Δp with a threshold. The threshold can be a predetermined threshold. (As described above...)

[0129] Figure 2 The fluids mentioned can include fuels. Fluids can include liquefied natural gas (LNG), such as methane.

[0130] When each of the primary fluid tank 127 and the secondary fluid tank 129 includes a level sensor 248, 250 for determining the height of the liquefied fluid within the fluid tanks 127, 129, the first step of blocking the fluid flow from one of the primary fluid tanks and the secondary fluid tank to the second pressurized fluid conduit assembly when the pressure drop Δp exceeds a threshold may include blocking the fluid flow from one of the primary fluid tanks and the secondary fluid tank 129 (relative to the height of the liquefied fluid inside the other of the primary fluid tanks 127 and the secondary fluid tank 129, which has the lowest height of the liquefied fluid determined by the level sensor 248, 250) to the second pressurized fluid conduit assembly 226, while the fluid flow from the other 127, 129 continues. However, alternatively, the first blocking may be performed by blocking the fluid flow from either of the primary fluid tanks 127 and the secondary fluid tank 129.

[0131] When sensor 230 includes a pressure sensor for measuring the pressure of fluid in pressurized section 204 or the second pressurized fluid conduit assembly, the step of determining the pressure drop Δp associated with the fluid flow through the second pressurized fluid conduit assembly 226 may include measuring the pressure drop Δp using the pressure sensor.

[0132] Unless otherwise stated, it should be noted that Figure 3 The method steps shown and described herein do not necessarily have to be in the form of Figure 3 The order shown in the diagram is executed.

[0133] Figure 5A schematic diagram of a control device 228 is shown, which may include a control unit 400, which may correspond to or include one or more of the aforementioned units 260, 262, and 264 of the control device 228. The control unit 400 may include a computing unit 401, which may be composed of substantially any suitable type of processor or microcomputer, such as circuitry for digital signal processing (Digital Signal Processor, DSP), or circuitry with a predetermined specific function (Application-Specific Integrated Circuit, ASIC). The computing unit 401 is connected to a storage unit 402 arranged within the control unit 400. The storage unit 402 provides the computing unit 401 with, for example, stored program code and / or stored data, which the computing unit 401 requires to perform calculations. The computing unit 401 may also be arranged to store portions or final results of calculations in the storage unit 402.

[0134] Additionally, the control unit 400 may be provided with means 411, 412, 413, and 414 for receiving and transmitting input and output signals. These input and output signals may contain waveforms, pulses, or other attributes, which can be detected as information by the means 411 and 413 for receiving input signals and can be converted into signals that can be processed by the computing unit 401. These signals are then made available to the computing unit 401. The means 412 and 414 for transmitting output signals are arranged to convert the signals received from the computing unit 401 to generate an output signal, for example, by modulating the signal, which can be transmitted to other parts and / or systems in the vehicle 100.

[0135] Each connection of a device used to receive and transmit input and output signals may consist of one or more cables, data buses such as CAN bus (Controller Area Network bus), MOST bus (Media-Oriented System Transport Bus), or some other bus configuration; or may be formed via a wireless connection.

[0136] Control systems in modern vehicles typically include a communication bus system, which comprises one or more communication buses or controllers for linking multiple electronic control units (ECUs) and various components located within the vehicle. Such control systems can include a large number of control devices and / or control units, and can divide the responsibility for specific functions among more than one control unit. Therefore, vehicles of the type shown typically include more than […]. Figure 2 and Figure 5 The invention includes a wide variety of control units, as is well known to those skilled in the art. Alternatively or additionally, embodiments of the invention may be implemented, in whole or in part, in one or more other control units already present in the vehicle.

[0137] In this document and throughout the present invention, a unit is generally described as a step for performing a method according to an embodiment of the invention. This also includes the unit being designed and / or arranged to perform those method steps.

[0138] Units 260, 262, and 264 of control device 228 are in Figure 2 The units 260, 262, and 264 are shown as separate units. However, these units 260, 262, and 264 may be logically separate but physically implemented in the same unit, or they may be arranged together logically and physically. These units 260, 262, and 264 may, for example, correspond to sets of instructions, which may be in the form of program code, and are input to and utilized by the processor / computing unit 401 when the unit is active and / or used to perform its method steps.

[0139] According to embodiments of the invention, a control device 228, which may include one or more control units 400 (e.g., a device or controller), may be configured to perform all the method steps mentioned above, in the claims, and in connection with the embodiments described herein. The control device 228 is associated with the aforementioned advantages of each respective embodiment.

[0140] According to a second aspect of the invention, a computer program 403 including instructions is provided (see...). Figure 5 When the program is executed by a computer, the instructions cause the computer to perform a method according to one or more embodiments disclosed above.

[0141] According to a third aspect of the invention, a computer-readable medium comprising instructions, which, when executed by a computer, cause the computer to perform one or more methods according to the embodiments disclosed above.

[0142] Those skilled in the art will understand that the embodiments of the method described herein according to the first aspect can be implemented in computer program 403, which, when executed in a computer, instructs the computer to perform the method. The computer program typically comprises a computer program product stored on a non-transitory / non-volatile digital storage medium, wherein the computer program is incorporated into a computer-readable medium of the computer program product. Computer-readable media include suitable memories, such as, for example: ROM (Read-Only Memory), PROM (Programmable Read-Only Memory), EPROM (Erasable PROM), flash memory, EEPROM (Electrically Erasable PROM), hard disk units, etc.

[0143] This invention is not limited to the embodiments described above. Rather, this invention relates to and covers all different embodiments included within the scope of the independent claims.

Claims

1. A method for determining the state of a primary fluid storage tank (127) or one or more secondary fluid storage tanks (129), each of the primary fluid storage tank and the secondary fluid storage tanks (127, 129) being arranged to contain a fluid or a mixture of fluids available in liquefied and evaporated forms, wherein The primary fluid storage tank and the secondary fluid storage tanks (127, 129) are part of the pressurized section (204) of the fluid system (202), wherein Each of the primary fluid storage tank and the secondary fluid storage tanks (127, 129) has a first air inlet line (206, 208) having an inlet (210, 212) located inside the primary fluid storage tank and the secondary fluid storage tank (127, 129), and the first air inlet line (206, 208) is part of the pressurization section (204), wherein The inlets (210, 212) of the first intake lines (206, 208) are arranged to primarily receive the liquid of the fluid, wherein The primary fluid tank and the secondary fluid tanks (127, 129) are vapor-connected to each other via a first pressurized fluid conduit device (214), allowing the vapor of the fluid to travel from one of the primary fluid tank (127) and the secondary fluid tank (129) to the other, wherein the first pressurized fluid conduit device (214) is part of the pressurized section (204) of the fluid system (202). The first intake lines (206, 208) are arranged to be fluidly connected to the second pressurized fluid conduit assembly (226) and to provide fluid flow from the main fluid tank and the secondary fluid tanks (127, 129) to the second pressurized fluid conduit assembly (226), which is part of the pressurized section (204) of the fluid system (202), wherein... The fluid system (202) includes one or more sensors (230) for determining one or more pressures of the fluid in the pressurized section (204), wherein the method includes: • By using the sensor, determine (301) one or more pressure drops associated with the fluid flow through the second pressurized fluid conduit device. (Δp) ; • When the pressure drop (Δp) When the threshold is exceeded, the fluid flow from one of the main fluid tank and the secondary fluid tank to the second pressurized fluid conduit device is blocked (303), while the fluid flow from the other of the main fluid tank and the secondary fluid tank to the second pressurized fluid conduit device continues; as well as • When the fluid flow from one of the main fluid tank and the secondary fluid tank to the second pressurized fluid conduit is blocked, while the fluid flow from the other of the main fluid tank and the secondary fluid tank to the second pressurized fluid conduit continues, the pressure drop associated with the fluid flow through the second pressurized fluid conduit is determined (304) by using the sensor. (Δp) The method further includes: • When the fluid flow from one of the main fluid tank and the secondary fluid tank to the second pressurized fluid conduit is blocked, if the pressure drop (Δp) If the value returns to a value below the threshold, it is determined (305) that one of the primary fluid storage tank and the secondary fluid storage tank has no liquefied fluid, or the method further includes: • When the fluid flow from one of the main fluid tank and the secondary fluid tank to the second pressurized fluid conduit is blocked, if the pressure drop (Δp) If the flow remains above the threshold, the fluid flow from the other of the primary fluid tank and the secondary fluid tank to the second pressurized fluid conduit device is blocked (306), while the fluid flow from the one of the primary fluid tank and the secondary fluid tank with the previously blocked fluid flow to the second pressurized fluid conduit device is allowed. • When the fluid flow from one of the main fluid tanks and the secondary fluid tanks to the second pressurized fluid conduit is blocked, while the fluid flow from the one of the main fluid tanks and the secondary fluid tanks with the previously blocked fluid flow to the second pressurized fluid conduit is permitted, the pressure drop associated with the fluid flow through the second pressurized fluid conduit is determined (307) by using the sensor. (Δp) ; • When the fluid flow from the primary fluid tank and the other of the secondary fluid tank to the second pressurized fluid conduit is blocked, if the pressure drop (Δp) If the value remains above the threshold, it is determined (308) that there is no liquefied fluid in the primary fluid storage tank and the secondary fluid storage tank; • When the fluid flow from the primary fluid tank and the other of the secondary fluid tank to the second pressurized fluid conduit is blocked, if the pressure drop (Δp) If the value returns to a value below the threshold, it is determined (309) that there is no liquefied fluid in the other of the primary fluid tank and the secondary fluid tank.

2. The method of claim 1, wherein each of the primary fluid storage tank and the secondary fluid storage tanks (127, 129) includes a level sensor (248, 250), the level sensor being arranged to determine the height of the liquefied fluid within the primary fluid storage tank and the secondary fluid storage tanks (127, 129), wherein when the pressure drop... (Δp) When the threshold is exceeded, the first step of blocking (303) the fluid flow from one of the main fluid tank and the secondary fluid tank (127, 129) to the second pressurized fluid conduit device (226) includes blocking (303) the fluid flow from one of the main fluid tank and the secondary fluid tank (127, 129) to the second pressurized fluid conduit device (226), while the fluid flow from the other of the main fluid tank and the secondary fluid tank (127, 129) continues relative to the height of the liquefied fluid in the other of the main fluid tank and the secondary fluid tank (127, 129), which has the lowest height of the liquefied fluid determined by the level sensor (248, 250).

3. The method according to claim 1 or 2, wherein the method includes determining the pressure drop. (Δp) Compare with the threshold (302).

4. The method according to any one of the preceding claims, wherein the sensor (230) comprises a pressure sensor for measuring the pressure of the fluid in the pressurizing section (204), and wherein the pressure drop associated with the fluid flow through the second pressurized fluid conduit device (226) is determined (301, 304, 307). (Δp) The steps include measuring the pressure drop using the pressure sensor. (Δp) .

5. The method according to any one of the preceding claims, wherein the fluid comprises fuel.

6. The method according to any one of the preceding claims, wherein the fluid comprises liquefied natural gas (LNG).

7. A computer program product comprising instructions that, when executed by a computer, cause the computer to perform the method according to any one of claims 1 to 6.

8. A computer-readable medium comprising instructions that, when executed by a computer, cause the computer to perform the method according to any one of claims 1 to 6.

9. A control device (228) for determining the state of a primary fluid storage tank (127) or one or more secondary fluid storage tanks (129), each of the primary fluid storage tank and the secondary fluid storage tanks (127, 129) being arranged to contain a fluid or a mixture of fluids available in liquefied and evaporated forms, wherein The primary fluid storage tank and the secondary fluid storage tanks (127, 129) are part of the pressurized section (204) of the fluid system (202), wherein Each of the primary fluid storage tank and the secondary fluid storage tanks (127, 129) has a first air inlet line (206, 208) having an inlet (210, 212) located inside the primary fluid storage tank and the secondary fluid storage tank (127, 129), and the first air inlet line (206, 208) is part of the pressurization section (204), wherein The inlets (210, 212) of the first intake lines (206, 208) are arranged to primarily receive the liquid of the fluid, wherein The primary fluid tank and the secondary fluid tanks (127, 129) are arranged in vapor communication with a ventilator connector (224) via a first pressurized fluid conduit (214), allowing vapor of the fluid to travel from one of the primary fluid tank (127) and the secondary fluid tank (129) to the other, wherein the first pressurized fluid conduit (214) is part of the pressurized section (204) of the fluid system (202). The first intake lines (206, 208) are arranged to be fluidly connected to the second pressurized fluid conduit assembly (226) and to provide fluid flow from the main fluid tank and the secondary fluid tanks (127, 129) to the second pressurized fluid conduit assembly (226), which is part of the pressurized section (204) of the fluid system (202), wherein... The fluid system (202) includes one or more sensors (230) for determining one or more pressures of the fluid in the pressurization section (204), wherein the control device (228) is configured to: By using the sensor (230), one or more pressure drops associated with the fluid flow through the second pressurized fluid conduit device (226) are determined. Δp ), When the pressure drop ( Δp When the threshold is exceeded, the fluid flow from one of the main fluid tank and the secondary fluid tank (127, 129) to the second pressurized fluid conduit device (226) is blocked, while the fluid flow from the other of the main fluid tank and the secondary fluid tank (127, 129) to the second pressurized fluid conduit device (226) continues. When the fluid flow from one of the main fluid storage tank and the secondary fluid storage tank (127, 129) to the second pressurized fluid conduit device (226) is blocked, if the pressure drop ( Δp If the value returns to a value below the threshold, it is determined that one of the primary fluid storage tank and the secondary fluid storage tank (127, 129) contains no liquefied fluid. When the fluid flow from one of the main fluid storage tank and the secondary fluid storage tank (127, 129) to the second pressurized fluid conduit device (226) is blocked, if the pressure drop ( Δp If the flow rate remains above the threshold, the fluid flow from one of the main fluid tanks (127, 129) to the second pressurized fluid conduit (226) is blocked, while the fluid flow from one of the main fluid tanks (127, 129) with the previously blocked fluid flow to the second pressurized fluid conduit (226) is permitted. When the fluid flow from the other of the primary fluid storage tank and the secondary fluid storage tank (127, 129) to the second pressurized fluid conduit device (226) is blocked, if the pressure drop ( Δp If the fluid level remains above the threshold, it is determined that there is no liquefied fluid in the primary fluid storage tank and the secondary fluid storage tanks (127, 129), and When the fluid flow from the other of the primary fluid storage tank and the secondary fluid storage tank (127, 129) to the second pressurized fluid conduit device (226) is blocked, if the pressure drop ( Δp If the value returns to a value below the threshold, it is determined that the other of the primary fluid tank and the secondary fluid tank (127, 129) has no liquefied fluid.

10. A fluid system (202) comprising a pressurization section (204), said pressurization section (204) including A main fluid storage tank (127) is arranged to contain a fluid or a mixture of fluids available in liquefied and evaporated forms. One or more secondary fluid storage tanks (129) are arranged to contain a fluid or a mixture of fluids available in liquefied and evaporated forms, wherein each of the primary fluid storage tank and the secondary fluid storage tanks (127, 129) has a first inlet line (206, 208) having an inlet (210, 212) located inside the primary fluid storage tank and the secondary fluid storage tanks (127, 129), the first inlet line (206, 208) being part of the pressurization section (204), wherein the inlet (210, 212) of the first inlet line (206, 208) is arranged to primarily receive the liquid of the fluid. A first pressurized fluid conduit (214) is arranged to fluidly connect the primary fluid tank and the secondary fluid tanks (127, 129) via a vent connector (224) of the first pressurized fluid conduit (214), thereby providing vapor communication between the primary fluid tank and the secondary fluid tanks (127, 129), allowing vapor of the fluid to travel from one of the primary fluid tank (127) and the secondary fluid tank (129) to the other of the primary fluid tank (127) and the secondary fluid tank (129). A second pressurized fluid conduit device (226) is arranged to be fluidly connected to the first inlet lines (206, 208), wherein the first inlet lines (206, 208) are arranged to provide fluid flow from the main fluid tank and the secondary fluid tanks (127, 129) to the second pressurized fluid conduit device (226), wherein The fluid system (202) includes one or more sensors (230) for determining one or more pressures of the fluid in the pressurization section (204), and wherein the fluid system (202) includes the control device (228) according to claim 9.

11. The fluid system (202) of claim 10, wherein each of the primary fluid tank and the secondary fluid tank (127) has a vent (216, 218) arranged to be fluidly connected to the first pressurized fluid conduit (214), wherein when the primary fluid tank (127) is installed, the inlet (210) of the first air inlet line (206) of the primary fluid tank (127) is located at a level below the vent (216) of the primary fluid tank (127), and wherein when the secondary fluid tank (129) is installed, the inlet (212) of the first air inlet line (208) of each secondary fluid tank (129) is located at a level below the vent (218) of the secondary fluid tank (129).

12. The fluid system (202) of claim 11, wherein the first pressurized fluid conduit device (214) comprises a main valve device (220) and a secondary valve device (222), each of the main valve device and the secondary valve devices (220, 222) being arranged to be manually operated, and wherein the vent outlet (216) of the main fluid tank (127) is fluidly connected via the main valve device and the secondary valve devices (220, 222) to the vent outlet (218) of the secondary fluid tank (129).

13. The fluid system (202) according to any one of claims 10 to 12, wherein each of the primary fluid tank and the secondary fluid tank (127, 129) has a second inlet line (240, 242), the second inlet line having an inlet (244, 246) located within the primary fluid tank and the secondary fluid tank (127, 129), the second inlet line (240, 242) being part of the pressurization section (204), wherein the inlet (244, 246) of the second inlet line (240, 242) is arranged to receive vapor of the fluid, wherein the second inlet line (240, 242) is arranged to provide from the primary fluid tank The evaporation fluid flow from the secondary fluid storage tanks (127, 129) to the second pressurized fluid conduit device (226), wherein when the main fluid storage tank (127) is installed, the inlet (210) of the first air inlet line (206) of the main fluid storage tank (127) is located at a horizontal level below the inlet (244) of the second air inlet line (240) of the main fluid storage tank (127), and wherein when the secondary fluid storage tank (129) is installed, the inlet (212) of the first air inlet line (208) of the secondary fluid storage tank (129) is located at a horizontal level below the inlet (246) of the second air inlet line (242) of the secondary fluid storage tank (129).

14. The fluid system (202) according to any one of claims 10 to 13, wherein each of the primary fluid tank and the secondary fluid tanks (127, 129) is arranged to contain a fluid in the form of liquefied natural gas (LNG).

15. A vehicle (100) comprising a fluid system (202) according to any one of claims 10 to 14.

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