Gaseous fuel system for vehicle and method therefor

Abstract

A gaseous fuel system comprises a plurality of fuel tanks and a controller. Each fuel tank is configured to store a gaseous fuel comprising a blend of hydrogen and methane and comprises a tank valve, a pressure sensor, and a temperature sensor. The controller is configured to: determine an initiation and a termination of a fuel filling operation; determine, an initial blend of the gaseous fuel prior to the initiation of the fuel filling operation, monitor, during the fuel filling operation, the pressure within each fuel tank using the pressure sensor and the temperature of the gaseous fuel flowing into each fuel tank using the temperature sensor; and determine, based on the pressure and the temperature monitored during the fuel filling operation and the initial blend, a final blend of the gaseous fuel stored in the plurality of fuel tanks subsequent to the termination of the fuel filling operation.

Description

GASEOUS FUEL SYSTEM FOR VEHICLE AND METHOD THEREFORTechnical Field

[0001] The present application relates to a gaseous fuel system for a vehicle and a method for a gaseous fuel system.

[0002] Due to the global movement to reduce carbon emissions, there is a growing interest in the use of hydrogen as a fuel source for vehicles. However, due to limited availability and high associated costs, there has been a reluctance in the transition to hydrogen as the fuel source for vehicles. Renewable natural gas (RNG) is widely available today and is a carbon neutral and cost competitive alternative to diesel.

[0003] Current internal combustion engines are capable of operating on RNG or hydrogen, and may be adapted to operate on different blends of RNG and hydrogen. However, conventional gaseous fuel systems may not be suitable for storing varying blends of RNG and hydrogen, and delivering the blends of RNG and hydrogen to the internal combustion engines.

[0004] An improved gaseous fuel system for a vehicle comprises a plurality of fuel tanks configured to be mounted on the vehicle. Each fuel tank from the plurality of fuel tanks is configured to store a gaseous fuel comprising a blend of hydrogen and methane. Each fuel tank comprises a tank valve configured toselectively allow flow of the gaseous fuel into and out of the fuel tank. Each fuel tank further comprises a pressure sensor configured to sense a pressure within the fuel tank. Each fuel tank further comprises a temperature sensor configured to sense a temperature of the gaseous fuel flowing into the fuel tank. The gaseous fuel system further comprises a fill line in fluid communication with the tank valve of each fuel tank. The gaseous fuel system further comprises a controller in communication with the pressure sensor and the temperature sensor of each fuel tank. The controller is configured to determine an initiation and a termination of a fuel filling operation. The fuel filling operation comprises supplying the gaseous fuel to the plurality of fuel tanks via the fill line. The controller is further configured to determine an initial blend of the gaseous fuel stored in the plurality of fuel tanks prior to the initiation of the fuel filling operation. The controller is further configured to monitor, during the fuel filling operation, the pressure within each fuel tank using the pressure sensor. The controller is further configured to monitor, during the fuel filling operation, the temperature of the gaseous fuel flowing into each fuel tank using the temperature sensor. The controller is further configured to determine, based on the pressure and the temperature monitored during the fuel filling operation and the initial blend, a final blend of the gaseous fuel stored in the plurality of fuel tanks subsequent to the termination of the fuel filling operation.

[0005] Another improved gaseous fuel system for a vehicle comprises a plurality of fuel tanks configured to be mounted on the vehicle. Each fuel tank from the plurality of fuel tanks is configured to store a gaseous fuel comprising a blend of hydrogen and methane. Each fuel tank comprises a tank valve configured to selectively allow flow of the gaseous fuel into and out of the fuel tank. Each fuel tank further comprises a pressure sensor configured to sense a pressure within the fuel tank. The gaseous fuel system further comprises a fill line in fluid communication with the tank valve of each fuel tank. The gaseousfuel system further comprises a weighing device configured to measure a weight of the plurality of fuel tanks. The gaseous fuel system further comprises a controller in communication with the weighing device and the pressure sensor of each fuel tank. The controller is configured to determine an initiation and a termination of a fuel filling operation. The fuel filling operation comprises supplying the gaseous fuel to the plurality of fuel tanks via the fill line. The controller is further configured to determine an initial blend of the gaseous fuel stored in the plurality of fuel tanks prior to the initiation of the fuel filling operation. The controller is further configured to monitor, during the fuel filling operation, the pressure using the pressure sensor. The controller is further configured to monitor, during the fuel filling operation, the weight of the plurality of fuel tanks using the weighing device. The controller is further configured to determine, based on the pressure and the weight monitored during the fuel filling operation and the initial blend, a final blend of the gaseous fuel stored in the plurality of fuel tanks subsequent to the termination of the fuel filling operation.

[0006] An improved method for a gaseous fuel system having a plurality of fuel tanks is provided. Each fuel tank from the plurality of fuel tanks is configured to store a gaseous fuel including a blend of hydrogen and methane. Each fuel tank has a tank valve configured to selectively allow flow of the gaseous fuel into and out of the fuel tank, a pressure sensor configured to sense a pressure within the fuel tank, and a temperature sensor configured to sense a temperature of the gaseous fuel flowing into the fuel tank. The method comprises determining an initiation and a termination of a fuel filling operation. The fuel filling operation comprises supplying the gaseous fuel to the plurality of fuel tanks via a fill line. The method further comprises determining an initial blend of the gaseous fuel stored in the plurality of fuel tanks prior to the initiation of the fuel filling operation. The method further comprises monitoring, during afuel filling operation, the pressure within each fuel tank using the pressure sensor. The method further comprises monitoring, during the fuel filling operation, the temperature of the gaseous fuel flowing into each fuel tank using the temperature sensor. The method further comprises determining, based on the pressure and the temperature monitored during the fuel filling operation and the initial blend, a final blend of the gaseous fuel stored in the plurality of fuel tanks subsequent to the termination of the fuel filling operation.

[0007] FIG. 1 is a schematic diagram of a gaseous fuel system for a vehicle, according to an embodiment of the present disclosure;

[0008] FIG. 2 is a schematic perspective view of a plurality of fuel tanks of the gaseous fuel system, according to an embodiment of the present disclosure;

[0009] FIG. 3 is a schematic side view diagram of a vehicle with the gaseous fuel system, according to an embodiment of the present disclosure;

[0010] FIG. 4 is an exemplary graph depicting a variation of temperature of gaseous fuels having different blends of hydrogen and methane supplied to a fuel tank at various different pressures with respect to time; and

[0011] FIG. 5 is a flowchart illustrating a method for a gaseous fuel system, according to an embodiment of the present disclosure.Detailed Description

[0012] Referring to FIG. 1, there is shown a schematic diagram of a gaseous fuel system 100 for a vehicle 10 (shown in FIG. 3), according to an embodiment of the present disclosure. The vehicle 10 may be of any suitable type, including,but not limited to, cars, trucks, buses, recreational vehicles, etc. The vehicle 10 comprises an internal combustion engine 20. The internal combustion engine 20 may operate on a gaseous fuel comprising methane, hydrogen, or a blend thereof.

[0013] The gaseous fuel system 100 comprises a plurality of fuel tanks 102 configured to be mounted on the vehicle 10. The plurality of fuel tanks 102 may form a tank assembly 101. The tank assembly 101 may be mounted on the vehicle 10 using any suitable mounting arrangement.

[0014] The tank assembly 101 is also schematically shown in FIG. 2. As shown in FIG. 2, the gaseous fuel system 100 may further comprise a frame 140. The plurality of fuel tanks 102 may be mounted to the frame 140 in a stacked configuration 142. In the stacked configuration 142, the plurality of fuel tanks 102 may be positioned on top of each other. The frame 140 may be configured to support the plurality of fuel tanks 102 in the stacked configuration 142. In some embodiments, the plurality of fuel tanks 102 may be mounted on the vehicle 10 in the stacked configuration 142.

[0015] Each fuel tank 102 from the plurality of fuel tanks 102 is configured to store a gaseous fuel comprising a blend of hydrogen and methane. As used herein, the term “hydrogen” refers to hydrogen gas. The term “methane” refers to a methane-based gas, such as compressed natural gas (CNG) and renewable natural gas (RNG). As used herein, the term “blend” refers to a mixture of hydrogen and methane. For example, the gaseous fuel may comprise a blend of 0% hydrogen and 100% methane, by moles; a blend of 100% hydrogen and 0% methane, by moles; a blend of 50% hydrogen and 50% methane, by moles; a blend of 33% hydrogen and 67% methane, by moles, and so forth. Accordingly, each fuel tank 102 may be a high pressure fuel tank suitable for storing the gaseous fuel. In some examples, each fuel tank 102 may withstand a pressure of 700 bars or more.

[0016] Each fuel tank 102 comprises a tank valve 104 configured to selectively allow flow of the gaseous fuel into and out of the fuel tank 102. Specifically, the tank valve 104 may comprise a shut-off valve 105 to selectively allow the flow of the gaseous fuel into and out of the fuel tank 102. The shutoff valve 105 of each fuel tank 102 may be electronically and independently operable, for example, by a controller. In some embodiments, the shut-off valve 105 may be a solenoid shut-off valve.

[0017] In some embodiments, the tank valve 104 may further comprise one or more pressure relief devices 130. The one or more pressure relief devices 130 may mitigate emergency situations in which the pressure within the fuel tank 102 increases above a threshold pressure level. In some embodiments, the one or more pressure relief devices 130 may be temperature-triggered pressure relief devices.

[0018] Each fuel tank 102 further comprises a pressure sensor 106 configured to sense a pressure within the fuel tank 102. In other words, the pressure sensor 106 may sense the pressure exerted by the gaseous fuel stored within the fuel tank 102. In some embodiments, the pressure sensor 106 may be integrated into the tank valve 104 of each fuel tank 102. That is, in some embodiments, the tank valve 104 of each fuel tank 102 may comprise the pressure sensor 106.

[0019] Each fuel tank 102 further comprises a temperature sensor 108 configured to sense a temperature of the gaseous fuel flowing into the fuel tank 102. For example, the temperature sensor 108 may sense the temperature of the gaseous fuel while the gaseous fuel is being filled into or supplied to the fuel tank 102. In some embodiments, the temperature sensor 108 may be integrated into the tank valve 104 of each fuel tank 102. That is, in some embodiments, the tank valve 104 of each fuel tank 102 may comprise the temperature sensor 108. In some embodiments, the pressure sensor 106 and the temperature sensor 108may be integrated into the tank valve 104 of each fuel tank 102. That is, in some embodiments, the tank valve 104 of each fuel tank 102 may comprise the pressure sensor 106 and the temperature sensor 108.

[0020] The gaseous fuel system 100 further comprises a fill line 110 in fluid communication with the tank valve 104 of each fuel tank 102. Specifically, the fill line 110 may be in fluid communication with the shut-off valve 105. In some examples, the gaseous fuel system 100 may further comprise one or more fill ports 112 in fluid communication with the fill line 110. The one or more fill ports 112 may provide access to the fill line 110.

[0021] The gaseous fuel may be supplied to the plurality of fuel tanks 102 via the fill line 110 during a fuel filling operation (also referred to as a “refueling event”). The fuel filling operation comprises supplying the gaseous fuel to the plurality of fuel tanks 102 via the fill line 110.

[0022] As discussed above, the gaseous fuel comprises a blend of hydrogen and methane. Prior to an initiation of the fuel filling operation, the plurality of fuel tanks 102 may store an initial blend of the gaseous fuel. The initial blend of the gaseous fuel may refer to the blend (or composition) of hydrogen and methane in the gaseous fuel that is stored in the plurality of fuel tanks 102 before the initiation of the fuel filling operation. Furthermore, upon a termination of the fuel filling operation, the plurality of fuel tanks 102 may store a final blend of the gaseous fuel. The final blend of the gaseous fuel may refer to the blend (or composition) of hydrogen and methane stored in the plurality of fuel tanks 102 subsequent to the termination of the fuel filling operation.

[0023] The gaseous fuel system 100 may further comprise a supply line 126 in fluid communication with the tank valve 104 of each fuel tank 102. Specifically, the supply line 126 may be in fluid communication with the shut-off valve 105. The supply line 126 may be configured to deliver the final blend of the gaseous fuel to the internal combustion engine 20 of the vehicle 10 (shown in FIG. 3). The gaseous fuel system 100 may further comprise one or more filters 132 in fluid communication with the supply line 126. The one or more filters 132 may be configured to filter impurities in the final blend of the gaseous fuel before the final blend of the gaseous fuel is delivered to the internal combustion engine 20.

[0024] In some embodiments, the gaseous fuel system 100 may further comprise a pressure regulator 128 in fluid communication with the supply line 126. The pressure regulator 128 may be configured to regulate a pressure of the final blend of the gaseous fuel delivered to the internal combustion engine 20. The pressure regulator 128 may be configured according to the specification of the internal combustion engine 20. In some examples, the gaseous fuel system 100 may further comprise a vent line 136 and coolant lines 138 in fluid communication with the pressure regulator 128. The vent line 136 and the coolant lines 138 may promote safe operation of the pressure regulator 128.

[0025] In some embodiments, the gaseous fuel system 100 may further comprise a regulator pressure sensor 134 and a regulator temperature sensor 135 disposed downstream of the pressure regulator 128. The regulator pressure sensor 134 and the regulator temperature sensor 135 may be configured to sense the pressure and the temperature, respectively, of the gaseous fuel supplied to the internal combustion engine 20 via the pressure regulator 128.

[0026] The gaseous fuel system 100 may further comprise a plurality of tank lines 120 corresponding to the plurality of fuel tanks 102. Each tank line 120 may be in fluid communication with the tank valve 104 of a corresponding fuel tank 102. The gaseous fuel system 100 may further comprise a connecting line 122 in fluid communication with each of the plurality of tank lines 120. Thegaseous fuel system 100 may further comprise an intermediary line 124 in fluid communication with the connecting line 122 and the fill line 110. The supply line 126 may be in fluid communication with the intermediary line 124 and the internal combustion engine 20 of the vehicle. In some embodiments, the fill line 110 and the intermediary line 124 may be integral with each other.

[0027] The gaseous fuel system 100 may further comprise a weighing device 116. The weighing device 116 is schematically depicted by a block in FIG. 1. The weighing device 116 is configured to measure a weight of the plurality of fuel tanks 102. The weighing device 116 may have any suitable configuration, such that a total weight of the plurality of fuel tanks 102 may be determined using the weighing device 116.

[0028] In some embodiments, the weighing device 116 may individually measure a weight of each fuel tank 102. Specifically, in some embodiments, the weighing device 116 may comprise a plurality of load cells 118 (schematically depicted by a block in FIG. 1) corresponding to the plurality of fuel tanks 102. Each load cell 118 from the plurality of load cells 118 may be configured to measure a weight of a corresponding fuel tank 102 from the plurality of fuel tanks 102. The total weight of the plurality of fuel tanks 102 may be determined by adding the corresponding weights of the plurality of fuel tanks 102. In some embodiments, the plurality of load cells 118 may be integrated into the frame 140 (shown in FIG. 2).

[0029] FIG. 3 illustrates a schematic side view diagram of the vehicle 10 with the gaseous fuel system 100, according to an embodiment of the present disclosure.

[0030] As discussed above, the vehicle 10 comprises the internal combustion engine 20. The internal combustion engine 20 may operate on the gaseous fuel stored in the plurality of fuel tanks 102.

[0031] The vehicle 10 further comprises an engine control unit (ECU) 30 associated with the internal combustion engine 20. The engine control unit 30 may be configured to control operation of the internal combustion engine 20. For example, the engine control unit 30 may be configured to select an engine operating mode on the basis of the blend of the gaseous fuel. The internal combustion engine 20 and the engine control unit 30 are schematically depicted by blocks in FIG. 3. While the vehicle 10 is depicted as a heavy vehicle in FIG.3, it may be noted that the vehicle 10 may be of any suitable type.

[0032] Referring to FIGS. 1 and 3, the gaseous fuel system 100 further comprises a controller 114 (schematically depicted by a block in FIG. 3). The controller 114 may be an electronic controller, comprising one or more processors and memories, including a permanent memory, such as FLASH or EEPROM, and a temporary memory, such as SRAM or DRAM, for storing and executing a program. It may be noted that the controller 114 may be different from the engine control unit 30.

[0033] The controller 114 is in communication with the pressure sensor 106 and the temperature sensor 108 of each fuel tank 102. The controller 114 may be in wired or wireless communication with the pressure sensor 106 and the temperature sensor 108 of each fuel tank 102. In some embodiments, the controller 114 may be in communication with the shut-off valve 105 of each tank valve 104.

[0034] The controller 114 is configured to determine the initiation and the termination of the fuel filling operation. As discussed above, the fuel fillingoperation comprises supplying the gaseous fuel to the plurality of fuel tanks 102 via the fill line 110. Specifically, the fuel filling operation may comprise supplying the gaseous fuel to the plurality of fuel tanks 102 via the fill line 110 from an external fuel source.

[0035] The initiation of the fuel filling operation may correspond to the time instance at which the gaseous fuel starts to flow into the plurality of fuel tanks 102 from the external fuel source. The termination of the fuel filling operation may correspond to the time instance at which the flow of the gaseous fuel into the plurality of fuel tanks 102 stops.

[0036] The fuel filling operation may be performed when desired. As an example, the fuel filling operation may be performed when the gaseous fuel within the plurality of fuel tanks 102 decreases below a threshold level. In some cases, the fuel filling operation may be performed when the pressure of the gaseous fuel within the plurality of fuel tanks 102 decreases below a threshold pressure level. The threshold pressure level may vary depending upon the specification of the internal combustion engine 20.

[0037] The controller 114 is further configured to determine the initial blend of the gaseous fuel stored in the plurality of fuel tanks 102 prior to the initiation of the fuel filling operation. In some embodiments, the initial blend of the gaseous fuel may be determined based on an immediately previous fuel filling operation. It may be noted that the initial blend of the gaseous fuel may be the blend of the gaseous fuel in the plurality of fuel tanks 102 subsequent to the termination of the immediately previous fuel filling operation. The controller 114 may be configured to store information regarding the initial blend of the gaseous fuel on the memory thereof subsequent to the termination of the immediately previous fuel filling operation.

[0038] The controller 114 is further configured to monitor, during the fuel filling operation, the pressure within each fuel tank 102 using the pressure sensor 106. The controller 114 may be configured to receive pressure information representative of the pressure within each fuel tank 102 from the corresponding pressure sensor 106 during the fuel filling operation. The controller 114 may be configured to process the received pressure information from the pressure sensor 106 to determine and monitor the pressure within each fuel tank 102 during the fuel filling operation.

[0039] In some embodiments, the controller 114 may be further configured to monitor, during the fuel filling operation, the temperature of the gaseous fuel flowing into each fuel tank 102 using the temperature sensor 108. The controller 114 may be configured to receive temperature information representative of the temperature of the gaseous fuel flowing into each fuel tank 102 from the corresponding temperature sensor 108 during the fuel filling operation. The controller 114 may be configured to process the received temperature information from the temperature sensor 108 to determine and monitor the temperature of the gaseous fuel flowing into each fuel tank 102 during the fuel filling operation.

[0040] As discussed above, in some embodiments, the gaseous fuel system 100 may comprise the weighing device 116. The weighing device 116 may be in communication with the controller 114. In some embodiments, the controller 114 may be further configured to monitor, during the fuel filling operation, the weight of the plurality of fuel tanks 102 using the weighing device 116.

[0041] In some embodiments, the controller 114 may be further configured to determine, based on the pressure and the temperature monitored during the fuel filling operation and the initial blend, a final blend of the gaseous fuel stored in the plurality of fuel tanks 102 subsequent to the termination of the fuel fillingoperation. The final blend of the gaseous fuel may refer to the blend (or composition) of hydrogen and methane in the gaseous fuel that is stored in the plurality of fuel tanks 102 upon the termination of the fuel filling operation. In such embodiments, the controller 114 may determine the final blend of the gaseous fuel on the basis of the initial blend, and the pressure and the temperature monitored during the fuel filling operation.

[0042] In some embodiments, the controller 114 may be further configured to determine, based on the pressure and the temperature monitored during the fuel filling operation, a current blend of the gaseous fuel supplied to the plurality of fuel tanks 102 via the fill line 110 during the fuel filling operation. The current blend of the gaseous fuel may refer to the blend (or composition) of hydrogen and methane in the gaseous fuel that is supplied to the plurality of fuel tanks 102 during the fuel filling operation. In such embodiments, the current blend may be determined based on a comparison of the pressure and the temperature monitored during the fuel filling operation with predetermined data. In other words, the controller 114 may determine the current blend of the gaseous fuel by comparing the pressure and the temperature monitored during the fuel filling operation with the predetermined data. The predetermined data may be obtained through experimentation. The predetermined data may comprise, for example, a look-up table. The final blend of the gaseous fuel may be an aggregate of the initial blend and the current blend of the gaseous fuel.

[0043] During the fuel filling operation, the gaseous fuel may undergo rapid expansion as it flows into the plurality of fuel tanks 102. During rapid expansion, hydrogen heats up, while methane cools down. The gaseous fuel may exhibit unique temperature characteristics depending upon the blend of hydrogen and methane of the gaseous fuel and the pressure at which the gaseous fuel is supplied to the plurality of fuel tanks 102 during the fuel filling operation. Insome embodiments, the predetermined data may represent the unique temperature characteristics at different pressures.

[0044] The temperature of the gaseous fuel may vary with respect to time as the gaseous fuel flows into each fuel tank 102 during the fuel filling operation. The controller 114 may monitor, using the temperature sensor 108, the change in the temperature of the gaseous fuel flowing into each fuel tank 102 with respect to time, and combine the variation of the temperature with the variation in pressure (monitored using the pressure sensor 106) within each fuel tank 102 during the fuel filling operation to determine the current blend of the gaseous fuel supplied to the plurality of fuel tanks 102 during the fuel filling operation. The controller 114 may utilize the predetermined data to determine the current blend of the gaseous fuel supplied to the plurality of fuel tanks 102 during the fuel filling operation, and subsequently determine the final blend of the gaseous fuel based on the initial blend and the current blend. The temperature characteristics of the gaseous fuel comprising different blends of hydrogen and methane will be discussed below with reference to FIG. 4.

[0045] Furthermore, in some embodiments, the controller 114 may be further configured to determine the final blend of the gaseous fuel further based on the weight monitored during the fuel filling operation. At the same pressure, hydrogen and methane have different weights. The controller 114 may further utilize the weight of the plurality of fuel tanks 102 monitored during the fuel filling operation to improve the accuracy of the determined current blend and / or the determined final blend of the gaseous fuel.

[0046] In some alternate embodiments, the controller 114 may be configured to determine, based on the pressure and the weight monitored during the fuel filling operation and the initial blend, the final blend of the gaseous fuel stored in the plurality of fuel tanks 102 subsequent to the termination of the fuel fillingoperation. In such embodiments, the controller 114 may determine the final blend of the gaseous fuel on the basis of the initial blend, and the pressure and the weight monitored during the fuel filling operation.

[0047] In some embodiments, the controller 114 may be further configured to determine, based on the pressure and the weight monitored during the fuel filling operation, the current blend of the gaseous fuel supplied to the plurality of fuel tanks 102 via the fill line 110 during the fuel filling operation. In such embodiments, the current blend may be determined based on a comparison of the pressure and the weight monitored during the fuel filling operation with the predetermined data. In other words, the controller 114 may determine the current blend of the gaseous fuel by comparing the pressure and the weight monitored during the fuel filling operation with the predetermined data. As discussed above, the final blend of the gaseous fuel may be an aggregate of the initial blend and the current blend of the gaseous fuel.

[0048] As discussed above, at the same pressure, hydrogen and methane have different weights. During the fuel filling operation, the weight of the plurality of fuel tanks 102 may increase proportionately to the blend of the gaseous fuel supplied to the plurality of fuel tanks 102 at a given pressure. Specifically, the gaseous fuel may exhibit unique weight characteristics depending upon the blend of hydrogen and methane of the gaseous fuel and the pressure at which the gaseous fuel is supplied to the plurality of fuel tanks 102 during the fuel filling operation. The predetermined data may represent the unique weight characteristics at different pressures.

[0049] The controller 114 may monitor, using the weighing device 116, the change in the weight of the plurality of fuel tanks 102 with respect to time, and combine the variation of the weight with the variation in pressure (monitored using the pressure sensor 106) within each fuel tank 102 during the fuel fillingoperation to determine the current blend of the gaseous fuel supplied to the plurality of fuel tanks 102 during the fuel filling operation. The controller 114 may utilize the predetermined data to determine the current blend of the gaseous fuel supplied to the plurality of fuel tanks 102 during the fuel filling operation, and subsequently determine the final blend of the gaseous fuel based on the initial blend and the current blend.

[0050] In some embodiments, the controller 114 may be further configured to determine the final blend of the gaseous fuel further based on the temperature monitored during the fuel filling operation. As discussed above, the gaseous fuel may exhibit unique temperature characteristics depending upon the blend of hydrogen and methane of the gaseous fuel and the pressure at which the gaseous fuel is supplied to the plurality of fuel tanks 102 during the fuel filling operation. The controller 114 may further utilize the temperature monitored during the fuel filling operation to improve the accuracy of the determined current blend and / or the determined final blend of the gaseous fuel.

[0051] The gaseous fuel system 100 may allow using the gaseous fuel having different blends of hydrogen and methane to operate the internal combustion engine 20. Furthermore, the gaseous fuel system 100 may facilitate adapting the internal combustion engine 20 to operate on the gaseous fuel having the different blends of hydrogen and methane.

[0052] The gaseous fuel system 100 may determine the final blend of the gaseous fuel stored in the plurality of fuel tanks 102 after each fuel filling operation. The gaseous fuel system 100 may actively monitor the gaseous fuel supplied to the plurality of fuel tanks 102 during the fuel filling operation to determine the current blend of the gaseous fuel. Furthermore, the gaseous fuel system 100 may account for the initial blend of the gaseous fuel stored in the plurality of fuel tanks 102 while determining the final blend of the gaseous fuel.The gaseous fuel system 100 may also enable calculation of carbon dioxide equivalent (CChe) savings that the vehicle 10 provides while operating on the gaseous fuel as compared to other fuels, such as diesel.

[0053] In some embodiments, the controller 114 may be further configured to determine, based on the pressure, the temperature, and the weight monitored during the fuel filling operation, the current blend of the gaseous fuel supplied to the plurality of fuel tanks 102 via the fill line 110 during the fuel filling operation. Determining the current blend of the gaseous fuel on the basis of the pressure, the temperature, and the weight monitored during the fuel filling operation may further improve the accuracy of the current blend of the gaseous fuel determined by the controller 114, and consequently, the final blend of the gaseous fuel determined by the controller 114.

[0054] The controller 114 may be in further communication with the engine control unit 30. The controller 114 may be configured to receive engine fuel demand signals from the engine control unit 30, and control the tank valve 104, or more specifically, the shut-off valve 105, of each fuel tank 102 as per the engine fuel demand signals. In some embodiments, the controller 114 may be configured to communicate the final blend of the gaseous fuel to the engine control unit 30 associated with the internal combustion engine 20. The engine control unit 30 may calibrate the operation of the internal combustion engine 20 depending upon the final blend of the gaseous fuel to meet power and emission requirements. For example, the engine control unit 30 may control engine timing parameters (e.g., fuel injection timing and ignition timing) of the internal combustion engine 20 based on the final blend of the gaseous fuel. In this way, the controller 114 and the engine control unit 30 may operate together to optimize operation of the internal combustion engine 20. In some embodiments, the final blend of the gaseous fuel may be communicated to the engine controlunit 30 prior to a start of the internal combustion engine 20. As a result, the internal combustion engine 20 may operate optimally throughout its operation.

[0055] FIG. 4 shows an exemplary graph 150 depicting a variation of temperature of gaseous fuels having different blends of hydrogen and methane supplied to a fuel tank at various different pressures with respect to time. Time is expressed in seconds in the abscissa (X-axis). Temperature is expressed in Kelvin (K) in the ordinate (Y-axis).

[0056] As a gaseous fuel is supplied to the fuel tank, the gaseous fuel mixes with a gas initially present in the fuel tank, thereby compressing it. This is referred to herein as “the compression effect.”

[0057] The graph 150 comprises a first curve 152 depicting a variation of the temperature of pure methane supplied to the fuel tank at 35 Megapascals (MPa) with respect to time. The graph 150 further comprises a second curve 154 depicting a variation of the temperature of the pure methane supplied to the fuel tank at 70 MPa with respect to time.

[0058] As depicted by the first curve 152 and the second curve 154, the temperature of the pure methane initially decreases, attributed to the Joule-Thomson (J-T) effect, which takes place during the isenthalpic expansion at a tank valve of the fuel tank. The cooling effect of the J-T effect diminishes with the increase in pressure within the fuel tank, and the gas temperature within the fuel tank begins to rise, as depicted by the first curve 152 (pure methane supplied at 35 MPa). As depicted by the second curve 154 (pure methane supplied at 70 MPa), the increase in temperature related to the increase in pressure within the fuel tank (or the compression effect) counteracts the J-T effect.

[0059] The graph 150 further comprises a third curve 156 depicting a variation of the temperature of pure hydrogen gas supplied to the fuel tank at 35 MPa with respect to time. The graph 150 further comprises a fourth curve 158 depicting a variation of the temperature of the pure hydrogen gas supplied to the fuel tank at 70 MPa with respect to time. As depicted by the third curve 156 and the fourth curve 158, the temperature of the pure hydrogen gas increases rapidly as the hydrogen gas expands within the fuel tank. Hydrogen has a negative J-T coefficient. Therefore, the initial expansion process causes an increase in temperature, which is then enhanced by the compression effect within the fuel tank.

[0060] The graph 150 further comprises curves 161, 162 depicting variations of the temperature of a first gas blend supplied to the fuel tank at 35 MPa and 70 MPa, respectively, with respect to time. The first gas blend comprises 95% methane and 5% hydrogen, by moles.

[0061] The graph 150 further comprises curves 163, 164 depicting variations of the temperature of a second gas blend supplied to the fuel tank at 35 MPa and 70 MPa, respectively, with respect to time. The second gas blend comprises 77% methane and 23% hydrogen, by moles.

[0062] The graph 150 indicates a decrease in the temperature of pure methane in the fuel tank, whereas, for pure hydrogen, the temperature rises rapidly at the onset of a fuel filling operation. Furthermore, blends of methane and hydrogen demonstrate unique temperature characteristics. A comprehensive dataset may be obtained with experimentation and used according to the present disclosure.

[0063] FIG. 5 illustrates a flowchart of a method 200 for a gaseous fuel system (e.g., the gaseous fuel system 100 of FIG. 1), according to an embodiment of the present disclosure. Specifically, the method 200 is for a gaseous fuelsystem having a plurality of fuel tanks. Each fuel tank from the plurality of fuel tanks is configured to store a gaseous fuel including a blend of hydrogen and methane. Each fuel tank has a tank valve configured to selectively allow flow of the gaseous fuel into and out of the fuel tank, a pressure sensor configured to sense a pressure within the fuel tank, and a temperature sensor configured to sense a temperature of the gaseous fuel flowing into the fuel tank. The method 200 may be performed by any suitable controller (e.g., the controller 114 shown in FIG. 3). The method 200 will be discussed with further reference to FIGS. 1 and 3. The method 200 comprises the following steps:

[0064] At step 202, the method 200 comprises determining an initiation and a termination of a fuel filling operation. The fuel filling operation comprises supplying the gaseous fuel to the plurality of fuel tanks via a fill line. Referring to FIG. 1, for example, the method 200 may comprise determining the initiation and the termination of the fuel filling operation comprising supplying the gaseous fuel to the plurality of fuel tanks 102 via the fill line 110.

[0065] At step 204, the method 200 further comprises determining an initial blend of the gaseous fuel stored in the plurality of fuel tanks prior to the initiation of the fuel filling operation. Referring to FIG. 1, for example, the method 200 may comprise determining the initial blend of the gaseous fuel stored in the plurality of fuel tanks 102 prior to the initiation of the fuel filling operation.

[0066] In some embodiments, the initial blend of the gaseous fuel may be determined based on an immediately previous fuel filling operation.

[0067] At step 206, the method 200 further comprises monitoring, during a fuel filling operation, the pressure within each fuel tank using the pressure sensor. Referring to FIG. 1, for example, the method 200 may comprisemonitoring the pressure within each fuel tank 102 using the pressure sensor 106 during the fuel filling operation.

[0068] At step 208, the method 200 further comprises monitoring, during the fuel filling operation, the temperature of the gaseous fuel flowing into each fuel tank using the temperature sensor. Referring to FIG. 1, for example, the method 200 may comprise monitoring the temperature of the gaseous fuel flowing into each fuel tank 102 using the temperature sensor 108 during the fuel filling operation.

[0069] At step 210, the method 200 further comprises determining, based on the pressure and the temperature monitored during the fuel filling operation and the initial blend, a final blend of the gaseous fuel stored in the plurality of fuel tanks subsequent to the termination of the fuel filling operation. Referring to FIG. 1, for example, the method 200 may further comprise determining the final blend of the gaseous fuel stored in the plurality of fuel tanks 102 subsequent to the termination of the fuel filling operation based on the pressure and the temperature monitored during the fuel filling operation and the initial blend.

[0070] In some embodiments, the method 200 may further comprise determining, based on the pressure and the temperature monitored during the fuel filling operation, a current blend of the gaseous fuel supplied to the plurality of fuel tanks via the fill line during the fuel filling operation. Referring to FIG.1 , for example, the method 200 may comprise determining the current blend of the gaseous fuel supplied to the plurality of fuel tanks 102 via the fill line 110 during the fuel filling operation based on the pressure and the temperature monitored during the fuel filling operation.

[0071] In some embodiments, the current blend may be determined based on a comparison of the pressure and the temperature monitored during the fuelfilling operation with predetermined data. The predetermined data may be obtained through experimentation. The predetermined data may comprise, for example, a look-up table. The final blend of the gaseous fuel may be an aggregate of the initial blend and the current blend of the gaseous fuel.

[0072] Using the method 200, the gaseous fuel system may allow using the gaseous fuel having different blends of hydrogen and methane to operate an internal combustion engine of a vehicle. Furthermore, the method 200 may facilitate adapting the internal combustion engine to operate on the gaseous fuel having the different blends of hydrogen and methane.

[0073] The method 200 may allow determining the final blend of the gaseous fuel stored in the plurality of fuel tanks after each fuel filling operation. The method 200 may comprise actively monitoring the gaseous fuel supplied to the plurality of fuel tanks during the fuel filling operation to determine the current blend of the gaseous fuel. Furthermore, the method 200 may account for the initial blend of the gaseous fuel while determining the final blend of the gaseous fuel. The method 200 may also enable calculation of carbon dioxide equivalent (CChe) savings that the vehicle provides while operating on the gaseous fuel as compared to other fuels, such as diesel.

[0074] In some embodiments, the method 200 may further comprise monitoring, during the fuel filling operation, a weight of the plurality of fuel tanks using a weighing device. The method 200 may further comprise determining the final blend of the gaseous fuel further based on the weight monitored during the fuel filling operation. Referring to FIG. 1, for example, the method 200 may comprise monitoring the weight of the plurality of fuel tanks 102 using the weighing device 116 during the fuel filling operation, and determining the final blend of the gaseous fuel further based on the weight monitored during the fuel filling operation.

[0075] In some embodiments, the method 200 may further comprise determining, based on the pressure, the temperature, and the weight monitored during the fuel filling operation, the current blend of the gaseous fuel supplied to the plurality of fuel tanks via the fill line during the fuel filling operation. Referring to FIG. 1, for example, the method 200 may comprise determining the current blend of the gaseous fuel supplied to the plurality of fuel tanks 102 via the fill line 110 during the fuel filling operation based on the pressure, the temperature, and the weight monitored during the fuel filling operation.

[0076] In some embodiments, the method 200 may further comprise communicating the final blend of the gaseous fuel to an engine control unit associated with an internal combustion engine of a vehicle. Referring to FIG. 3, for example, the method 200 may comprise communicating the final blend of the gaseous fuel to the engine control unit 30 associated with the internal combustion engine 20 of the vehicle 10.

[0077] By communicating the final blend of the gaseous fuel to the engine control unit, the engine control unit may calibrate the operation of the internal combustion engine depending upon the final blend of the gaseous fuel to meet power and emission requirements. For example, the engine control unit may control engine timing parameters (e.g., fuel injection timing and ignition timing) of the internal combustion engine based on the final blend of the gaseous fuel. In this way, the method 200 may allow operating the internal combustion engine in an optimized manner.

[0078] In some embodiments, the final blend of the gaseous fuel may be communicated to the engine control unit prior to a start of the internal combustion engine. Referring to FIG. 3, for example, the final blend of the gaseous fuel may be communicated to the engine control unit 30 prior to the start of the internal combustion engine 20.

[0079] While particular elements, embodiments, and applications of the present invention have been shown and described, it will be understood that the invention is not limited thereto since modifications can be made by those skilled in the art without departing from the scope of the present disclosure, particularly in light of the foregoing teachings.

Claims

What is claimed is:

1. A gaseous fuel system for a vehicle, the gaseous fuel system comprising:a plurality of fuel tanks configured to be mounted on the vehicle, wherein each fuel tank from the plurality of fuel tanks is configured to store a gaseous fuel comprising a blend of hydrogen and methane, wherein each fuel tank comprises:a tank valve configured to selectively allow flow of the gaseous fuel into and out of the fuel tank;a pressure sensor configured to sense a pressure within the fuel tank; anda temperature sensor configured to sense a temperature of the gaseous fuel flowing into the fuel tank;a fill line in fluid communication with the tank valve of each fuel tank; anda controller in communication with the pressure sensor and the temperature sensor of each fuel tank, wherein the controller is configured to:determine an initiation and a termination of a fuel filling operation, the fuel filling operation comprising supplying the gaseous fuel to the plurality of fuel tanks via the fill line;determine an initial blend of the gaseous fuel stored in the plurality of fuel tanks prior to the initiation of the fuel filling operation;monitor, during the fuel filling operation, the pressure within each fuel tank using the pressure sensor;monitor, during the fuel filling operation, the temperature of the gaseous fuel flowing into each fuel tank using the temperature sensor; anddetermine, based on the pressure and the temperature monitored during the fuel filling operation and the initial blend, a final blend of the gaseous fuel stored in the plurality of fuel tanks subsequent to the termination of the fuel filling operation.

2. The gaseous fuel system of claim 1, wherein the initial blend of the gaseous fuel is determined based on an immediately previous fuel filling operation.

3. The gaseous fuel system of claim 1, wherein the controller is further configured to determine, based on the pressure and the temperature monitored during the fuel filling operation, a current blend of the gaseous fuel supplied to the plurality of fuel tanks via the fill line during the fuel filling operation.

4. The gaseous fuel system of claim 3, wherein the current blend is determined based on a comparison of the pressure and the temperature monitored during the fuel filling operation with predetermined data.

5. The gaseous fuel system of claim 3, wherein the final blend of the gaseous fuel is an aggregate of the initial blend and the current blend of the gaseous fuel.

6. The gaseous fuel system of claim 1, further comprising a weighing device configured to measure a weight of the plurality of fuel tanks, wherein the weighing device is in communication with the controller, and wherein the controller is further configured to:monitor, during the fuel filling operation, the weight of the plurality of fuel tanks using the weighing device; anddetermine the final blend of the gaseous fuel further based on the weight monitored during the fuel filling operation.

7. The gaseous fuel system of claim 6, wherein the controller is further configured to determine, based on the pressure, the temperature, and the weight monitored during the fuel filling operation, a current blend of the gaseous fuel supplied to the plurality of fuel tanks via the fill line during the fuel filling operation.

8. The gaseous fuel system of claim 6, wherein the weighing device comprises a plurality of load cells corresponding to the plurality of fuel tanks, wherein each load cell from the plurality of load cells is configured to measure a weight of a corresponding fuel tank from the plurality of fuel tanks.

9. The gaseous fuel system of claim 1, further comprising a frame, wherein the plurality of fuel tanks is mounted to the frame in a stacked configuration.

10. The gaseous fuel system of claim 1, wherein the pressure sensor and the temperature sensor are integrated into the tank valve of each fuel tank.

11. The gaseous fuel system of claim 1, further comprising a supply line in fluid communication with the tank valve of each fuel tank, wherein the supply line is configured to deliver the final blend of the gaseous fuel to an internal combustion engine of the vehicle.

12. The gaseous fuel system of claim 11, further comprising a pressure regulator in fluid communication with the supply line, wherein thepressure regulator is configured to regulate a pressure of the final blend of the gaseous fuel delivered to the internal combustion engine.

13. The gaseous fuel system of claim 11, wherein the controller is configured to communicate the final blend of the gaseous fuel to an engine control unit associated with the internal combustion engine.

14. The gaseous fuel system of claim 13, wherein the final blend of the gaseous fuel is communicated to the engine control unit prior to a start of the internal combustion engine.

15. The gaseous fuel system of claim 11, further comprising:a plurality of tank lines corresponding to the plurality of fuel tanks, wherein each tank line is in fluid communication with the tank valve of a corresponding fuel tank;a connecting line in fluid communication with each of the plurality of tank lines; andan intermediary line in fluid communication with the connecting line and the fill line;wherein the supply line is in fluid communication with the intermediary line and the internal combustion engine of the vehicle.

16. A gaseous fuel system for a vehicle, the gaseous fuel system comprising:a plurality of fuel tanks configured to be mounted on the vehicle, wherein each fuel tank from the plurality of fuel tanks is configured to store a gaseous fuel comprising a blend of hydrogen and methane, wherein each fuel tank comprises:a tank valve configured to selectively allow flow of the gaseous fuel into and out of the fuel tank; anda pressure sensor configured to sense a pressure within the fuel tank; anda fill line in fluid communication with the tank valve of each fuel tank;a weighing device configured to measure a weight of the plurality of fuel tanks; anda controller in communication with the weighing device and the pressure sensor of each fuel tank, wherein the controller is configured to:determine an initiation and a termination of a fuel filling operation, the fuel filling operation comprising supplying the gaseous fuel to the plurality of fuel tanks via the fill line; determine an initial blend of the gaseous fuel stored in the plurality of fuel tanks prior to the initiation of the fuel filling operation;monitor, during the fuel filling operation, the pressure using the pressure sensor;monitor, during the fuel filling operation, the weight of the plurality of fuel tanks using the weighing device; and determine, based on the pressure and the weight monitored during the fuel filling operation and the initial blend, a final blend of the gaseous fuel stored in the plurality of fuel tanks subsequent to the termination of the fuel filling operation.

17. The gaseous fuel system of claim 16, wherein the initial blend is determined based on an immediately previous fuel filling operation.

18. The gaseous fuel system of claim 16, wherein the controller is further configured to determine, based on the pressure and the weight monitored during the fuel filling operation, a current blend of the gaseous fuelsupplied to the plurality of fuel tanks via the fill line during the fuel filling operation.

19. The gaseous fuel system of claim 18, wherein the current blend is determined based on a comparison of the pressure and the weight monitored during the fuel filling operation with predetermined data.

20. The gaseous fuel system of claim 18, wherein the final blend of the gaseous fuel is an aggregate of the initial blend and the current blend of the gaseous fuel.

21. The gaseous fuel system of claim 16, wherein each fuel tank further comprises a temperature sensor configured to sense a temperature of the gaseous fuel flowing into the fuel tank, wherein the temperature sensor of each fuel tank is in communication with the controller, and wherein the controller is further configured to:monitor, during the fuel filling operation, the temperature of the gaseous fuel flowing into each fuel tank using the temperature sensor; and determine the final blend of the gaseous fuel further based on the temperature monitored during the fuel filling operation.

22. The gaseous fuel system of claim 21, wherein the controller is further configured to determine, based on the pressure, the temperature, and the weight monitored during the fuel filling operation, a current blend of the gaseous fuel supplied to the plurality of fuel tanks via the fill line during the fuel filling operation.

23. The gaseous fuel system of claim 21, wherein the pressure sensor and the temperature sensor are integrated into the tank valve of each fuel tank.

24. The gaseous fuel system of claim 16, further comprising a frame, wherein the plurality of fuel tanks is mounted to the frame in a stacked configuration.

25. The gaseous fuel system of claim 16, wherein the weighing device comprises a plurality of load cells corresponding to the plurality of fuel tanks, wherein each load cell from the plurality of load cells is configured to measure a weight of a corresponding fuel tank from the plurality of fuel tanks.

26. The gaseous fuel system of claim 16, further comprising a supply line in fluid communication with the tank valve of each fuel tank, wherein the supply line is configured to deliver the final blend of the gaseous fuel to an internal combustion engine of the vehicle.

27. The gaseous fuel system of claim 26, further comprising a pressure regulator in fluid communication with the supply line, wherein the pressure regulator is configured to regulate a pressure of the final blend of the gaseous fuel delivered to the internal combustion engine.

28. The gaseous fuel system of claim 26, wherein the controller is configured to communicate the final blend of the gaseous fuel to an engine control unit associated with the internal combustion engine.

29. The gaseous fuel system of claim 28, wherein the final blend of the gaseous fuel is communicated to the engine control unit prior to a start of the internal combustion engine.

30. The gaseous fuel system of claim 26, further comprising:a plurality of tank lines corresponding to the plurality of fuel tanks, wherein each tank line is in fluid communication with the tank valve of a corresponding fuel tank;a connecting line in fluid communication with each of the plurality of tank lines; andan intermediary line in fluid communication with the connecting line and the fill line;wherein the supply line is in fluid communication with the intermediary line and the internal combustion engine of the vehicle.

31. A method for a gaseous fuel system having a plurality of fuel tanks, each fuel tank from the plurality of fuel tanks being configured to store a gaseous fuel including a blend of hydrogen and methane, each fuel tank having a tank valve configured to selectively allow flow of the gaseous fuel into and out of the fuel tank, a pressure sensor configured to sense a pressure within the fuel tank, and a temperature sensor configured to sense a temperature of the gaseous fuel flowing into the fuel tank, the method comprising:determining an initiation and a termination of a fuel filling operation, the fuel filling operation comprising supplying the gaseous fuel to the plurality of fuel tanks via a fill line;determining an initial blend of the gaseous fuel stored in the plurality of fuel tanks prior to the initiation of the fuel filling operation;monitoring, during a fuel filling operation, the pressure within each fuel tank using the pressure sensor;monitoring, during the fuel filling operation, the temperature of the gaseous fuel flowing into each fuel tank using the temperature sensor; anddetermining, based on the pressure and the temperature monitored during the fuel filling operation and the initial blend, a final blend of the gaseous fuel stored in the plurality of fuel tanks subsequent to the termination of the fuel filling operation.

32. The method of claim 31, wherein the initial blend of the gaseous fuel is determined based on an immediately previous fuel filling operation.

33. The method of claim 31, further comprising determining, based on the pressure and the temperature monitored during the fuel filling operation, a current blend of the gaseous fuel supplied to the plurality of fuel tanks via the fill line during the fuel filling operation.

34. The method of claim 33, wherein the current blend is determined based on a comparison of the pressure and the temperature monitored during the fuel filling operation with predetermined data.

35. The method of claim 33, wherein the final blend of the gaseous fuel is an aggregate of the initial blend and the current blend of the gaseous fuel.

36. The method of claim 31, further comprising:monitoring, during the fuel filling operation, a weight of the plurality of fuel tanks using a weighing device; anddetermining the final blend of the gaseous fuel further based on the weight monitored during the fuel filling operation.

37. The method of claim 36, further comprising determining, based on the pressure, the temperature, and the weight monitored during the fuel fillingoperation, a current blend of the gaseous fuel supplied to the plurality of fuel tanks via the fill line during the fuel filling operation.

38. The method of claim 31, further comprising communicating the final blend of the gaseous fuel to an engine control unit associated with an internal combustion engine of a vehicle.

39. The method of claim 38, wherein the final blend of the gaseous fuel is communicated to the engine control unit prior to a start of the internal combustion engine.

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