Flowmeter failure determination method and hydrogen filling device

Abstract

The method for determining a flowmeter failure includes the following steps: using a flowmeter to measure the filling amount of hydrogen filled into the fuel tank of an automobile (S114); obtaining information on the pressure and temperature of the fuel tank (S102); calculating the filling amount of hydrogen filled into the fuel tank based on the obtained pressure and temperature and the capacity of the fuel tank taking into account the expansion rate of the fuel tank (S104, S112); and determining whether there is a failure in the flowmeter using the error value between the measured filling amount and the calculated filling amount (S118).

Description

Technical Field

[0001] The present invention relates to a technique for determining a failure of a metering machine included in a hydrogen filling device. Background Art

[0002] Conventionally, a method for diagnosing a failure of a flowmeter of a metering machine has been developed. The method includes the following steps: using an error value between a measured filling amount at the end of filling measured by a flowmeter and an arithmetic filling amount at the end of filling calculated using the pressure, temperature, and capacity of a tank, based on a plurality of past actual data stored in a storage device, and an error value between a measured filling amount at the end of filling of hydrogen this time measured by the flowmeter and an arithmetic filling amount at the end of filling calculated using the pressure, temperature, and capacity of the tank, to determine whether there is a failure in the flowmeter and output a result (see Patent Document 1).

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2019-207196 Summary of the Invention

[0006] Problems to be Solved by the Invention

[0007] In addition, the difference between the measured filling amount and the arithmetic filling amount is caused by the expansion of the fuel tank and is usually not zero but has an offset. Therefore, in the above-described failure diagnosis method, when using the difference between the measured filling amount and the arithmetic filling amount as an error value to determine a failure, a tolerance value considering a specified offset is set. However, through further investigation by the inventors of the present application, it has been found that the expansion rate of the fuel tank is not necessarily constant but depends on the filling pressure.

[0008] The present invention has been completed in view of such a situation, and one of its exemplary purposes is to provide a new technique for improving the accuracy of determining a failure of a flowmeter.

[0009] Solutions to the Problems

[0010] A method for determining a failure of a flowmeter according to a certain aspect of the present invention includes the following steps: using a flowmeter to measure the filling amount of hydrogen filled into a fuel tank of an automobile; acquiring information on the pressure and temperature of the fuel tank; calculating the filling amount of hydrogen filled into the fuel tank based on the acquired pressure and temperature and the capacity of the fuel tank considering the expansion rate of the fuel tank; and using an error value between the measured filling amount and the calculated filling amount to determine whether there is a failure in the flowmeter.

[0011] Effects of the Invention

[0012] According to a certain aspect of the present invention, the accuracy of fault determination of a flowmeter can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 FIG. is a diagram showing an example of the structure of a hydrogen filling system of a hydrogen refueling station according to the present embodiment.

[0014] Figure 2 FIG. is a structural diagram showing an example of the internal structure of a control circuit that controls the entire hydrogen filling system according to the present embodiment.

[0015] Figure 3 FIG. is a diagram showing an example of the change in the percentage error of the flowmeter with respect to the number of fillings.

[0016] Figure 4 FIG. is a diagram showing another example of the change in the percentage error of the flowmeter with respect to the number of fillings.

[0017] Figure 5 FIG. is a flowchart showing a part of the process of the hydrogen filling method in the present embodiment.

[0018] Figure 6 FIG. is a flowchart showing the remaining part of the process of the hydrogen filling method in the present embodiment.

[0019] Figure 7 FIG. is a diagram for explaining a hydrogen filling method using a multi-stage accumulator.

[0020] Figure 8 FIG. is a chart showing the relationship between the pressure difference during filling and the filling amount error of each filling data in Table 1. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0021] First, aspects of the present invention are listed. The flowmeter fault determination method according to a certain aspect of the present invention includes the following steps: measuring the filling amount of hydrogen filled into a fuel tank of an automobile using a flowmeter; obtaining information on the pressure and temperature of the fuel tank; calculating the filling amount of hydrogen filled into the fuel tank based on the obtained pressure and temperature and the capacity of the fuel tank taking into account the expansion rate of the fuel tank; and determining whether there is a fault in the flowmeter using the error value between the measured filling amount and the calculated filling amount.

[0022] According to this aspect, when calculating the filling amount, the expansion rate of the fuel tank is taken into account, so the calculation accuracy of the filling amount is improved. In other words, the error value between the measured filling amount and the calculated filling amount becomes smaller, and in addition, since the deviation becomes smaller, the accuracy of fault determination of the flowmeter is improved.

[0023] Alternatively, it may also include a step of outputting the determined result. By outputting the determination result of whether the flowmeter is faulty, it is possible to quickly grasp whether the flowmeter is faulty.

[0024] Alternatively, it may also include the following steps: calculating the first weight of hydrogen in the fuel tank before filling based on the first pressure, first temperature, and first volume of the fuel tank before the start of filling; and calculating the second weight of hydrogen in the fuel tank after filling based on the second pressure, second temperature, and second volume of the fuel tank after the start of filling. Alternatively, the calculated filling amount may be calculated using the first weight and the second weight. By using the first volume before filling and the second volume after filling respectively, the calculation accuracy of the filling amount can be improved.

[0025] Alternatively, the first volume is calculated using the expansion rate and the first pressure, and the second volume is calculated using the expansion rate and the second pressure. By calculating the first volume using the first pressure, the first weight before filling can be calculated with high accuracy. In particular, in the case where the pressure in the fuel tank before filling is low, the first volume taking into account the expansion rate can be calculated with high accuracy. In addition, by calculating the second volume using the second pressure, the second weight after filling can be calculated with high accuracy. In particular, in the case where the pressure in the fuel tank after filling is high, the second volume taking into account the expansion rate can be calculated with high accuracy. Thus, compared with the case where the volume is set to be constant regardless of the pressure in the fuel tank, the calculation accuracy of the filling amount can be improved.

[0026] Alternatively, the first volume is calculated using a non-linear first function for the first pressure, and the second volume is calculated using a linear or non-linear second function for the second pressure. The first function and the second function are represented by mathematical expressions stored in the storage device, for example. The inventors of the present application focused on the following situation: the deviation between the measured filling amount and the calculated filling amount becomes larger in the case of a large filling amount (a large difference between the first pressure and the second pressure). In particular, when the first pressure is small, it will be a situation of a large filling amount. By calculating the first volume using a non-linear first function for the first pressure, the calculation accuracy of the first volume can be improved compared to the case of calculating the first volume using a function proportional to the pressure in the fuel tank.

[0027] Alternatively, it may also include a step of determining the type of the fuel tank. Alternatively, the first function and the second function may be set according to the type of the fuel tank. Thus, when filling hydrogen into the fuel tanks of various vehicle models, it is possible to perform the fault determination of the flowmeter.

[0028] Another aspect of the present invention is a hydrogen filling device. The device includes: a metering machine that uses a flow meter to measure the filling amount of hydrogen filled into a fuel tank of an automobile; an acquisition unit that acquires information on the pressure and temperature of the fuel tank; a filling amount calculation unit that calculates the filling amount of hydrogen filled into the fuel tank from the metering machine based on the acquired pressure and temperature and the capacity of the fuel tank taking into account the expansion rate of the fuel tank; and a determination unit that determines whether there is a failure in the flow meter using the error value between the filling amount measured by the flow meter and the calculated filling amount.

[0029] According to this aspect, when calculating the filling amount, the expansion rate of the fuel tank is taken into account. Therefore, the calculation accuracy of the filling amount is improved. In other words, the error value between the measured filling amount and the calculated filling amount becomes smaller. In addition, since the deviation becomes smaller, the accuracy of the failure determination of the flow meter is improved.

[0030] In addition, any combination of the above structural elements, and aspects obtained by transforming the expressions of the present invention among methods, devices, systems, etc. are also effective as aspects of the present invention. In addition, aspects obtained by appropriately combining the above elements are also included in the scope of the technical solutions claimed in the patent application of this case.

[0031] Hereinafter, based on a preferred embodiment, the present invention will be described with reference to the drawings. The embodiment is for illustration and does not limit the present invention. All features and their combinations described in the embodiment are not necessarily essential features of the present invention. The same or equivalent structural elements, components, and processes shown in the respective drawings are labeled with the same reference numerals, and repeated explanations are appropriately omitted. In addition, the scales and shapes of the respective parts shown in the respective drawings are set conveniently for easy explanation, and are not subject to restrictive interpretation unless otherwise specified. In addition, even for the same component, the scale etc. may sometimes be slightly different between the respective drawings. In addition, when terms such as "first" and "second" are used in this specification or claims, unless otherwise specified, they do not indicate any order or importance, but are used to distinguish one structure from other structures.

[0032] First, an example of a hydrogen filling system to which the present invention can be applied will be described. Figure 1 is a diagram showing an example of the structure of a hydrogen filling system of a hydrogen refueling station according to the present embodiment. In Figure 1 it, a hydrogen filling system 500 is disposed in a hydrogen refueling station 102. The hydrogen filling system (hydrogen filling device) 500 includes a multi-stage accumulator 101, a dispenser (metering machine) 30, a compressor 40, and a control circuit 100. The multi-stage accumulator 101 is composed of a plurality of accumulators 10, 12, 14 having different lower limit pressures.

[0033] In Figure 1In the example, a multi-stage accumulator 101 is composed of three accumulators 10, 12, and 14. For example, the accumulator 10 functions as the first accumulator (Japanese: 1st bank) with a low lower limit pressure, the accumulator 12 functions as the second accumulator (Japanese: 2nd bank) with a medium lower limit pressure, and the accumulator 14 functions as the third accumulator (Japanese: 3rd bank) with a high lower limit pressure. However, it is not limited to this. Each accumulator used as the first to third accumulators can be replaced as needed. In addition, a cartridge (Japanese: カードル), an intermediate accumulator, or a hydrogen production device (not shown) is also arranged in the hydrogen refueling station 102. A hydrogen trailer (not shown) for delivering the filled hydrogen comes to the hydrogen refueling station 102.

[0034] In Figure 1 , the suction side of the compressor 40 is connected to the above-mentioned cartridge, intermediate accumulator, filling tank of the hydrogen trailer, or hydrogen production device through a pipe.

[0035] The discharge side of the compressor 40 is connected to the accumulator 10 through a pipe via the valve 21. Similarly, the discharge side of the compressor 40 is connected to the accumulator 12 through a pipe via the valve 23. Similarly, the discharge side of the compressor 40 is connected to the accumulator 14 through a pipe via the valve 25.

[0036] The accumulator 10 is connected to the dispenser 30 through a pipe via the valve 22. The accumulator 12 is connected to the dispenser 30 through a pipe via the valve 24. The accumulator 14 is connected to the dispenser 30 through a pipe via the valve 26. In this way, the accumulators 10, 12, and 14 constituting the multi-stage accumulator 101 are commonly connected to the dispenser 30.

[0037] In Figure 1 , a stop valve 36, a flow regulating valve 33, a flow meter 37, a cooler 32 (pre-cooler), a stop valve 38, an emergency disconnect coupler 41, and a control circuit 43 are arranged in the dispenser 30. A nozzle 44 extending outside the dispenser 30 is arranged in the dispenser 30. The dispenser 30 delivers the hydrogen (hydrogen fuel) supplied from the multi-stage accumulator 101 to the cooler 32 via the stop valve 36, the flow regulating valve 33, and the flow meter 37. At this time, the flow rate of the hydrogen supplied from the multi-stage accumulator 101 per unit time is controlled by the flow regulating valve 33.

[0038] The dispenser 30 measures the filling amount of hydrogen gas filled from the multi-stage accumulator 101 into the fuel tank 202 of the FCV (Fuel Cell Vehicle) 200. Specifically, the mass flow rate of the hydrogen gas filled into the fuel tank 202 is measured by the flow meter 37. In this embodiment, as the flow meter 37, for example, a Coriolis mass flow meter is used. The control circuit 43 accumulates the mass flow rate measured by the flow meter 37 to measure the filling amount. The filling amount measured using the flow meter 37 is also referred to as the "metered filling amount". In addition, the filled hydrogen gas is cooled to, for example, -40 °C by the cooler 32. The cooled hydrogen gas is filled into the fuel tank 202 through the stop valve 38, the emergency disconnect coupler 41, and the nozzle 44 by using the pressure difference.

[0039] The control circuit 43 is configured to be able to communicate with the in-vehicle device 204 in the FCV 200. The control circuit 43 can wirelessly communicate with the in-vehicle device 204 using, for example, infrared rays. The control circuit 43 is connected to the control circuit 100 for controlling the entire hydrogen filling system 500. A display panel 39 is arranged on the outer surface of the dispenser 30. Alarm lights 34 and 35 are arranged inside the display panel 39.

[0040] In Figure 1 In the hydrogen filling system 500, a plurality of pressure gauges are arranged at different positions between the multi-stage accumulator 101 and the outlet of the dispenser 30 in the flow path of the hydrogen fuel. Specifically, the pressure in the accumulator 10 is measured by the pressure gauge 11. The pressure in the accumulator 12 is measured by the pressure gauge 13. The pressure in the accumulator 14 is measured by the pressure gauge 15. The pressure near the inlet in the dispenser 30 is measured by the pressure gauge 27. The pressure near the outlet in the dispenser 30 is measured by the pressure gauge 28.

[0041] In Figure 1 In the example of, the pressure gauge 27 measures the pressure on the upstream side (primary side) of the stop valve 36 located on the primary side of the cooler 32. The pressure gauge 28 measures the pressure near the emergency disconnect coupler 41 on the secondary side of the cooler 32. The pressure data measured by each pressure gauge is output to the control circuit 100 always or at a specified sampling period (for example, 10 msec to several seconds). In other words, the control circuit 100 monitors the pressure measured by each pressure gauge always or at a specified sampling period.

[0042] The pressure of the fuel tank 202 is measured by the pressure gauge 206 mounted on the FCV 200. As will be described later, during the period when communication is established between the in-vehicle device 204 and the control circuit 43, the pressure of the fuel tank 202 is monitored always or at a specified sampling interval (for example, 10 msec to several seconds).

[0043] The temperature of hydrogen near the outlet in the dispenser 30 is measured by the thermometer 29. The thermometer 29 measures the temperature on the secondary side of the cooler 32, i.e., near the emergency disconnect coupler 41, for example. In addition, the outside air temperature near the dispenser 30 is measured by the thermometer 31. The temperature data measured by each thermometer is always or output to the control circuit 100 at a specified sampling period (e.g., 10 msec to several tens of seconds). In other words, the control circuit 100 always or monitors the temperature measured by each thermometer at a specified sampling period.

[0044] The temperature of the fuel tank 202 is measured by the thermometer 207 mounted on the FCV 200. As will be described later, during the period when communication is established between the vehicle-mounted device 204 and the control circuit 43, the temperature of the fuel tank 202 is always or monitored at a specified sampling interval (e.g., 10 msec to several seconds).

[0045] The hydrogen pressurized in the canister, the intermediate accumulator, or the tank of the hydrogen trailer is supplied to the suction side of the compressor 40 in a state where it is decompressed to a low pressure (e.g., 0.6 MPa) by respective regulators (not shown) controlled by the control circuit 100. Similarly, the hydrogen produced by the hydrogen production device is supplied to the suction side of the compressor 40 in a low-pressure state (e.g., 0.6 MPa). The compressor 40 compresses the hydrogen supplied at low pressure under the control of the control circuit 100 and supplies the compressed hydrogen to the respective accumulators 10, 12, 14 of the multi-stage accumulator 101. The compressor 40 compresses the hydrogen until a specified high pressure (e.g., 82 MPa) is reached in each of the accumulators 10, 12, 14. In other words, the compressor 40 compresses the hydrogen until the secondary side pressure P OUT reaches a specified high pressure (e.g., 82 MPa).

[0046] The control circuit 100 determines any one of the canister, the intermediate accumulator, the hydrogen trailer, and the hydrogen production device as the supply source for supplying hydrogen to the suction side of the compressor 40. Similarly, the control circuit 100 determines which of the accumulators 10, 12, 14 to supply hydrogen from the compressor 40 by opening and closing the control valves 21, 23, 25. The control circuit 100 can also be controlled to supply hydrogen from the compressor 40 to two or more accumulators simultaneously.

[0047] In addition, in the above example, it is shown that the pressure P IN of the hydrogen supplied to the suction side of the compressor 40 is decompression-controlled to a specified low pressure (e.g., 0.6 MPa), but this is not limited thereto. For example, when supplying the hydrogen pressurized in the canister, the intermediate accumulator, or the hydrogen trailer to the suction side of the compressor 40, the hydrogen may not be decompressed, or may be decompressed to a pressure higher than the specified low pressure (e.g., 0.6 MPa).

[0048] The hydrogen gas pressurized in the multi-stage accumulator 101 is cooled by the cooler 32 in the dispenser 30 and supplied from the dispenser 30 to the FCV 200.

[0049] Figure 2 FIG. is a structural diagram showing an example of the internal structure of a control circuit that controls the entire hydrogen filling system according to the present embodiment. In Figure 2 the communication control circuit 50, the memory 51, the receiving unit 52, the target pressure / temperature calculation unit 54, the system control unit 58, the recovery pressure control unit 61, the supply control unit 63, the accumulator pressure receiving unit 66, the dispenser information receiving unit 67, the output unit 74, the gas weight calculation unit 85, the determination unit 86, the filling amount calculation unit 87, the filling amount error calculation unit 89, the determination unit 90, the determination unit 91, the recording / calculation unit 92, the average error calculation unit 93, the error difference calculation unit 94, the determination unit 95, the setting unit 96, the monitor 76, and storage devices such as the disk devices 80, 84, and 88 are arranged in the control circuit 100. The recovery pressure control unit 61 includes a valve control unit 60 and a compressor control unit 62. The supply control unit 63 includes a dispenser control unit 64 and a valve control unit 65.

[0050] Each unit such as the receiving unit 52, the target pressure / temperature calculation unit 54, the system control unit 58, the recovery pressure control unit 61 (the valve control unit 60 and the compressor control unit 62), the supply control unit 63 (the dispenser control unit 64 and the valve control unit 65), the accumulator pressure receiving unit 66, the dispenser information receiving unit 67, the output unit 74, the gas weight calculation unit 85, the determination unit 86, the filling amount calculation unit 87, the filling amount error calculation unit 89, the determination unit 90, the determination unit 91, the recording / calculation unit 92, the average error calculation unit 93, the error difference calculation unit 94, the determination unit 95, and the setting unit 96 includes a processing circuit, and the processing circuit includes a circuit, a computer, a processor, a circuit board, or a semiconductor device, etc. For example, as the processing circuit, a CPU (Central Processing Unit), an FPGA (Field-Programmable Gate Array), or an ASIC (Application Specific Integrated Circuit) can also be used.

[0051] The above-mentioned each unit may also use a shared processing circuit (the same processing circuit). Or different processing circuits (separate processing circuits) may be used. The input data required by the above-mentioned each unit or the results calculated by the above-mentioned each unit are stored in the memory 51 each time.

[0052] The storage device 80 stores FCV information such as the pressure P, temperature T, and capacity V of the fuel tank 202 received from the FCV 200. In addition, a conversion table 81 is stored in the storage device 80, and the conversion table 81 represents the correlation between the weight N of hydrogen in the fuel tank 202 corresponding to the FCV information and filling information such as the target pressure Pg and target temperature Tg of the hydrogen to be filled into the fuel tank 202. Also, a correction table 82 is stored in the storage device 80, and the correction table 82 is used to correct the result obtained from the conversion table 81.

[0053] The accumulator pressure receiving unit 66 always or at a prescribed sampling period receives the pressures measured by the pressure gauges 11, 13, 15 in the accumulator 10, and stores them together with the reception time in the storage device 84. The dispenser information receiving unit 67 always or at a prescribed sampling period receives the pressures measured by the pressure gauges 27, 28 in the dispenser 30, and stores them together with the reception time in the storage device 84. The dispenser information receiving unit 67 always or at a prescribed sampling period receives the temperature measured by the thermometer 29 in the dispenser 30, and stores it together with the reception time in the storage device 84.

[0054] As described above, the flowmeter 37 measures the filling amount (mass flow rate) of hydrogen filled into the fuel tank 202. The flowmeter 37 measures the instantaneous mass flow rate of filling, and generates pulses for example for every 1 g as a minute flow unit. The pulse signal is output to the control circuit 43. The control circuit 43 counts the number of pulses generated since the start of filling to accumulate the mass flow rate, thereby measuring the measured filling amount Mm.

[0055] During filling, the value of the measured filling amount Mm at the current time changes with time and is displayed on the display panel 39 arranged on the outer surface of the dispenser 30, and is output to the control circuit 100. The measured filling amount Mm is the original data for the cost paid by the consumer. In other words, the cost paid by the consumer (user) is the amount obtained by multiplying the displayed measured filling amount Mm by the price of hydrogen per unit filling amount. Therefore, the measurement accuracy of the flowmeter 37 is important.

[0056] As described above, the FCV 200 outputs FCV information such as the pressure P, temperature T, and capacity V of the fuel tank 202. The display panel 39 can also display these values. Specifically, the values of the pressure Pt and temperature Tt of the fuel tank 202 at the current time t can also be displayed on the display panel 39 while changing with time.

[0057] The control circuit 100 calculates the density ρ(P, T) of hydrogen gas in the fuel tank 202 by using the pressure P and temperature T of the fuel tank 202 and the compressibility inherent to hydrogen. The control circuit 100 calculates the weight N of the hydrogen gas in the fuel tank 202 by multiplying the density ρ(P, T) by the volume V of the fuel tank 202, i.e., N = ρ(P, T) × V. As the weight N, the control circuit 100 calculates a first weight N1 before the start of filling and a second weight N2 after the start of filling. The first weight N1 is calculated by multiplying the density ρ(P1, T1) calculated based on the first pressure (initial pressure) P1 and the first temperature (initial temperature) T1 of the fuel tank 202 before the start of filling by the volume V (i.e., N1 = ρ(P1, T1) × V). The second weight N2 is calculated by multiplying the density ρ(P2, T2) calculated based on the second pressure P2 and the second temperature T2 after the start of filling by the volume V (i.e., N2 = ρ(P2, T2) × V). Here, "after the start of filling" includes the timing at any time t during filling and the timing at the end of filling when filling is completed.

[0058] The control circuit 100 calculates the filling amount Mc of hydrogen gas by subtracting the first weight N1 from the second weight N2 (i.e., Mc = N2 - N1). The filling amount calculated based on the first weight N1 and the second weight N2 is also referred to as the "calculated filling amount". The calculated filling amount Mc is a value calculated by using the pressure P and temperature T of the fuel tank 202 and the compressibility inherent to hydrogen, and is a value calculated by the PVT method (volume method). The calculated filling amount Mc corresponds to the weight of the hydrogen gas filled into the fuel tank 202 after the start of filling.

[0059] The calculated filling amount Mc can be used to evaluate the appropriateness of the measured filling amount Mm measured by the flow meter 37. Therefore, the percentage error of the flow meter 37 is evaluated by dividing the filling amount error ΔM obtained by subtracting the calculated filling amount Mc from the measured filling amount Mm by the calculated filling amount Mc and then multiplying by 100.

[0060] Figure 3 is a diagram showing an example of the change in the percentage error of the flow meter 37 with respect to the number of fillings. In Figure 3 's example, an example of a case where no abnormality occurs in the flow meter 37 during the verification period is shown. In Figure 3 the vertical axis shows the percentage error of the flow meter 37, and the horizontal axis shows the number of fillings. As Figure 3 shown, by using a large number of filling results to verify the magnitude of the percentage error based on the timing of the number of fillings, it is possible to continuously confirm the change over time of the flow meter 37. According to Figure 3From the results, it can be seen that the percentage error of the flowmeter 37 converges stably within the amplitude Δ2. In addition, the reason why the percentage error of the flowmeter 37 is not zero and shifts by Δ1 to the positive side is that the fuel tank 202 expands due to filling, so there is a deviation caused by expansion in the calculation result of the PVT method.

[0061] Figure 4 FIG. is another example showing the change in the percentage error of the flowmeter with respect to the number of fillings. In Figure 4 the example, an example is shown in which an abnormality occurred in the flowmeter 37 during the verification period. In Figure 4 it, the percentage error of the flowmeter 37 is shown on the vertical axis, and the number of fillings is shown on the horizontal axis. In Figure 4 the example, it can be seen that as the number of fillings increases, the deviation of the percentage error of the flowmeter 37 becomes larger, and at the two times of the A-th and B-th fillings, the value changes significantly (shifts) in a step-like manner. The way of shifting of the value is also, in Figure 4 the example, the positive-side shift shifts to the negative side. In this way, the large change in the percentage error of the flowmeter 37 in a short period indicates that a large abnormality (fault) other than the change over time has occurred in the flowmeter 37.

[0062] First, for the deviation of the percentage error of the flowmeter 37, it can be discriminated only through the continuous verification based on a large number of fillings in this embodiment. On the other hand, in the conventional gravimetric method, usually only about 4 measurements are made. Therefore, in the conventional gravimetric method, it is difficult to determine whether the deviation has become larger. In addition, for the sudden large change (shift) in the percentage error of the flowmeter 37, through the continuous verification of this embodiment, the time point at which the percentage error of the flowmeter 37 changes significantly (shifts) can be determined, so that the abnormality of the flowmeter 37 can be detected.

[0063] From the above results, it can also be seen that it is useful to verify by comparing the calculated filling amount Mc and the measured filling amount Mm. Therefore, in this embodiment, the error value between the calculated filling amount Mc and the measured filling amount Mm is used for the fault diagnosis of the flowmeter 37. In addition, in Figure 3 and Figure 4 the example, the percentage error is used for explanation, but the error value that can be verified is not limited to this. Next, the case where the filling amount error ΔM = Mm - Mc, which is the difference between the calculated filling amount Mc and the measured filling amount Mm, is used as the error value will be described.

[0064] Figure 5 FIG. is a flowchart showing a part of the process of the hydrogen filling method in this embodiment.

[0065] Figure 6It is a flowchart showing the remaining part of the process of the hydrogen filling method in this embodiment.

[0066] In Figure 5 and Figure 6 in this embodiment, the hydrogen filling method in this embodiment implements a determination process (S100), an FCV information reception process (S102), a gas weight calculation process (S104), a determination process (S106), an initial weight setting process (S108), a filling process (S110), a filling amount calculation process (S112), a filling amount measurement process (S114), a filling amount error calculation process (S116), a determination process (S118), an alarm output process (S120), a determination process (S126), a filling stop processing process (S128), a recording / calculation process (S130), an average error calculation process (S132), a difference calculation process (S134), a determination process (S136), and an alarm output process (S138).

[0067] When the FCV 200 arrives at the hydrogen refueling station 102, the operator of the hydrogen refueling station 102 or the user of the FCV 200 connects (fits) and fixes the nozzle 44 of the dispenser 30 to the receiving port (socket) of the fuel tank 202 of the FCV 200. Then, the operator or the user presses the start filling button (not shown) in the display panel 39 of the dispenser 30.

[0068] As the determination process (S100), the control circuit 43 determines whether the operator or the user has pressed the start filling button. When the start filling button is pressed (S100: "Yes"), it proceeds to the FCV information reception process (S102). If the start button is not pressed (S100: "No"), it does not proceed to the next process. When the start filling button is pressed, communication is established between the in-vehicle unit 204 and the control circuit 43 (repeater).

[0069] As the FCV information reception process (S102), the reception unit 52 receives FCV information such as the temperature Tt, pressure Pt, and capacity V of the fuel tank 202 of the FCV 200 at the current time (time t) from the FCV 200. Specifically, it operates as follows. When communication is established between the in-vehicle unit 204 and the control circuit 43 (repeater), the FCV information (tank information) is output (sent) from the in-vehicle unit 204 in real time.

[0070] The FCV information is relayed by the control circuit 43 provided in the dispenser 30 and then transmitted to the control circuit 100 that controls the entire hydrogen filling system 500. Inside the control circuit 100, the receiving unit 52 receives the FCV information via the communication control circuit 50. During the period when communication is established between the vehicle-mounted device 204 and the control circuit 43, the FCV information is monitored constantly or at a prescribed sampling interval (e.g., 10 milliseconds to several seconds). The received FCV information is stored in the storage device 80 together with the information at the reception time.

[0071] As the gas weight calculation process (S104), the gas weight calculation unit 85 calculates the weight Nt of the hydrogen gas filled in the fuel tank 202 at the current time point (time t) using the PVT method. Specifically, the gas weight calculation unit 85 calculates the density ρ(Pt, Tt) of the hydrogen gas using the pressure Pt and temperature Tt of the fuel tank 202 at the current time point, and the compressibility factor inherent to hydrogen. The gas weight calculation unit 85 calculates the weight Nt of the hydrogen gas in the fuel tank 202 at the current time point as Nt = ρ(Pt, Tt) × V by multiplying the density ρ(Pt, Tt) by the volume V of the fuel tank 202.

[0072] As the determination process (S106), the determination unit 86 determines whether the determination process is the first determination process since the start of filling. If it is the first determination process (S106: "Yes"), it proceeds to the initial weight setting process (S108). If it is not the first determination process, that is, if it is the second and subsequent determination processes since the start of the current filling (S106: "No"), it continues with the filling process (S110) described later and proceeds to the filling amount calculation process (S112).

[0073] As the initial weight setting process (S108), if in the determination process (S106) it is the first determination process, that is, if it is before the start of filling, the setting unit 96 sets the calculated weight Nt of the hydrogen gas as the first weight N1. The first weight N1 can be calculated as N1 = ρ(P1, T1) × V using the FCV information (the first temperature T1 and the first pressure P1) before the start of filling.

[0074] As the filling process (S110), first, the target pressure / temperature calculation unit 54 reads out the conversion table 81 from the storage device 80, and calculates the target pressure Pg and the target temperature Tg corresponding to the first pressure P1, the first temperature T1, and the capacity V of the fuel tank 202, and the outside air temperature T'. In addition, the target pressure / temperature calculation unit 54 reads out the correction table 82 from the storage device 80 to correct the values obtained through the conversion table 81. The correction table 82 is used to correct the values obtained through the conversion table 81 by the correction values set based on the results obtained by experiments or simulations, etc., in the case where the error is large in the results obtained only by the data of the conversion table 81. The calculated target pressure Pg and target temperature Tg are output to the system control unit 58.

[0075] Next, hydrogen is filled into the fuel tank 202 from the multi-stage accumulator 101 via the distributor 30.

[0076] Figure 7 It is a diagram for explaining a method of filling hydrogen using a multi-stage accumulator. In Figure 7 the vertical axis shows the pressure and the horizontal axis shows the time. In the case where the FCV 200 performs pressure difference filling of hydrogen, usually, each accumulator 10, 12, 14 of the multi-stage accumulator 101 is pre-pressurized to the same pressure P0 (for example, 82 MPa). On the other hand, the fuel tank 202 becomes the first pressure P1 at the time t0 when the filling starts. The case of filling hydrogen into the fuel tank 202 starting from this state is described.

[0077] First, hydrogen filling into the fuel tank 202 starts from the first pressure accumulation body (for example, the accumulator 10). Specifically, the operation is as follows. The supply control unit 63 controls the supply unit 106 under the control of the system control unit 58 to supply hydrogen from the accumulator 10 to the fuel tank 202 of the FCV 200. Specifically, the system control unit 58 controls the distributor control unit 64 and the valve control unit 65. The distributor control unit 64 communicates with the control circuit 43 of the distributor 30 via the communication control circuit 50 to control the operation of the distributor 30.

[0078] Specifically, first, the control circuit 43 adjusts the opening degree of the flow rate adjustment valve in the distributor 30 to open the shut-off valves 36 and 38 in the distributor 30. Moreover, the valve control unit 65 outputs control signals to the valves 22, 24, and 26 via the communication control circuit 50 to control the opening and closing of each valve. Specifically, the valve 22 is opened, and the valves 24 and 26 are maintained closed. Thus, hydrogen is supplied from the accumulator 10 to the fuel tank 202. Due to the pressure difference between the accumulator 10 and the fuel tank 202, the hydrogen pressurized in the accumulator 10 moves toward the fuel tank 202 side at the filling speed adjusted by the flow rate adjustment valve, and the pressure of the fuel tank 202 gradually rises as shown by the dashed line Pt. Along with this, the pressure of the accumulator 10 (the curve indicated by "First") gradually decreases. Then, at the time point of time t1 after passing the lower limit pressure for use of the first pressurized body, the used accumulator is switched from the accumulator 10 to the second pressurized body (for example, the accumulator 12).

[0079] When switching to the accumulator 12, the valve control unit 65 outputs control signals to the valves 22, 24, and 26 via the communication control circuit 50 to control the opening and closing of each valve. Specifically, the valve 24 is opened, the valve 22 is closed, and the valve 26 is maintained closed. Thus, the pressure difference between the accumulator 12 and the fuel tank 202 becomes larger, so that a state with a fast filling speed can be maintained.

[0080] Then, due to the pressure difference between the second pressurized body (for example, the accumulator 12) and the fuel tank 202, the hydrogen pressurized in the accumulator 12 moves toward the fuel tank 202 side, and the pressure of the fuel tank 202 further gradually rises as shown by the dashed line Pt. Along with this, the pressure of the accumulator 12 (the curve indicated by "Second") gradually decreases. Then, at the time point of time t2 after passing the lower limit pressure for use of the second pressurized body, the used accumulator is switched from the accumulator 12 to the third pressurized body (for example, the accumulator 14).

[0081] When switching to the accumulator 14, the valve control unit 65 outputs control signals to the valves 22, 24, and 26 via the communication control circuit 50 to control the opening and closing of each valve. Specifically, the valve 26 is opened, the valve 24 is closed, and the valve 22 is maintained closed. Thus, the pressure difference between the accumulator 14 and the fuel tank 202 becomes larger, so that a state with a fast filling speed can be maintained.

[0082] Then, due to the pressure difference between the third pressurized body (for example, the accumulator 14) and the fuel tank 202, the hydrogen pressurized in the accumulator 14 moves toward the fuel tank 202 side, and the pressure of the fuel tank 202 further gradually rises as shown by the dashed line Pt. Along with this, the pressure of the accumulator 14 (the curve indicated by "Third") gradually decreases. Then, the hydrogen is filled by the third pressurized body until the pressure of the fuel tank 202 reaches the target pressure Pg (for example, 65 to 81 MPa).

[0083] As described above, hydrogen is filled into the fuel tank 202 in sequence starting from the first accumulator. In addition, when filling hydrogen into the fuel tank 202 of the FCV 200 through the dispenser 30, the filling amount of hydrogen during the filling period is measured.

[0084] During this filling period, as the filling amount calculation process (S112), the filling amount calculation unit 87 calculates the calculated filling amount Mc obtained by subtracting the first weight N1 from the current time weight Nt of hydrogen in the fuel tank 202. At the filling start time point, Nt = N1, so the calculated filling amount Mc is 0. In addition, after the filling starts, Nt = N2, so the calculated filling amount Mc after the filling starts is the value obtained by subtracting the first weight N1 from the second weight N2 (that is, Mc = N2 - N1).

[0085] Similarly, during the filling period, as the filling amount measurement process (S114), the dispenser 30 measures the measured filling amount Mm of hydrogen using the Coriolis flowmeter 37. Specifically, the flowmeter 37 measures the mass flow rate at the instant of filling and generates pulses, for example, every 1 g as a minute flow unit. The pulse signal is output to the control circuit 43.

[0086] The control circuit 43 counts the pulses input from the start of filling to accumulate the mass flow rate, thereby calculating the measured filling amount Mm. The measured filling amount Mm is output to the control circuit 100, received by the dispenser information receiving unit 67, and stored in the storage device 84 together with the measurement time t. The measured filling amount Mm at the filling start time point is 0.

[0087] Similarly, during the filling period, as the filling amount error calculation process (S116), the filling amount error calculation unit 89 calculates the filling amount error ΔM = Mm - Mc obtained by subtracting the calculated filling amount Mc from the measured filling amount Mm measured at the same timing (time t) when the calculated filling amount Mc is calculated. At the start of filling, both the measured filling amount Mm and the calculated filling amount Mc are zero, so the filling amount error ΔM is also zero.

[0088] Similarly, during the filling period, as the determination process (S118), the determination unit 90 uses the filling amount error ΔM to determine whether there is a failure in the flowmeter 37. Specifically, the determination unit 90 determines whether the filling amount error ΔM is within the range of not less than the lower limit allowable value α1 and not more than the upper limit allowable value α2. If the filling amount error ΔM is not within the range of not less than the lower limit allowable value α1 and not more than the upper limit allowable value α2 (S118: "No"), it proceeds to the alarm output process (S120). If the filling amount error ΔM is within the range of not less than the lower limit allowable value α1 and not more than the upper limit allowable value α2 (S118: "Yes"), it proceeds to the determination process (S126).

[0089] As an alarm output process (S120), when it is determined that the flowmeter 37 has failed, during the hydrogen filling period, the output unit 74 outputs an alarm indicating the failure of the flowmeter 37 to the dispenser 30. As an example of the alarm, an alarm lamp 34 indicating the failure of the flowmeter 37 lights up in the dispenser 30.

[0090] Similarly, during the filling period, as a determination process (S126), the determination unit 91 determines whether the pressure of the fuel tank 202 has reached the target pressure Pg. When the pressure of the fuel tank 202 reaches the target pressure Pg (S126: "Yes"), it enters the filling stop process (S128). When the pressure of the fuel tank 202 does not reach the target pressure Pg (S126: "No"), the filling continues, and it returns to the FCV information reception process (S102). During the filling period, the processes from the FCV information reception process (S102) to the determination process (S118) are repeated until the pressure of the fuel tank 202 reaches the target pressure Pg.

[0091] In summary, the dispenser 30 repeatedly measures the metered filling amount Mm of hydrogen during the filling period by using the flowmeter 37. At the same time, the filling amount calculation unit 87 repeatedly calculates the calculated filling amount Mc of hydrogen from the dispenser 30 to the fuel tank 202 by using the information of the pressure Pt, temperature Tt, and volume V of the fuel tank 202 during the filling period. The filling amount error calculation unit 89 repeatedly calculates the filling amount error ΔM obtained by subtracting the calculated filling amount Mc from the metered filling amount Mm at the same timing when the calculated filling amount Mc is calculated.

[0092] Then, during the filling period, the determination unit 90 compares the calculated filling amount Mc with the metered filling amount Mm to repeatedly determine whether the flowmeter 37 has failed. That is, the determination unit 90 determines whether the filling amount error ΔM obtained by subtracting the calculated filling amount Mc from the metered filling amount Mm is within the range of not less than the lower limit allowable value α1 and not more than the upper limit allowable value α2. Then, the dispenser 30 outputs an alarm such as lighting up the alarm lamp 34 when a failure of the flowmeter 37 occurs. In addition, during such a short period as the filling period, it may be difficult for the filling amount error ΔM to generate a large deviation. However, the control circuit 100 can detect a sudden large change (shift) in the filling amount error ΔM.

[0093] As the filling stop process (S128), when the pressure in the fuel tank 202 reaches the target pressure Pg, the filling of hydrogen is stopped and the filling process ends. Specifically, when the pressure measured by the pressure gauge 28 near the outlet of the dispenser 30 reaches the target pressure Pg, the dispenser control unit 64 determines that the pressure in the fuel tank 202 has reached the target pressure Pg, and closes the stop valves 36 and 38 in the dispenser 30. In addition, the valve control unit 65 outputs control signals to the valves 22, 24, and 26 via the communication control circuit 50 to control each valve to be closed.

[0094] Next, as the recording / arithmetic process (S130), the recording / arithmetic unit 92 calculates the final measured filling amount Mmf at the end of filling and the final calculated filling amount Mcf at the end of filling measured by the flow meter 37, and stores them in the storage device 88 as actual performance data in association with the data of the filling date and time. The final measured filling amount Mmf is the measured filling amount Mm at the end of filling, which is the mass flow rate accumulated from the start to the end of filling. The final calculated filling amount Mcf is the calculated filling amount Mc at the end of filling, which is calculated by subtracting the first weight N1 from the second weight N2 at the end of filling. In addition, the recording / arithmetic unit 92 calculates the final filling amount error ΔMf (=Mmf - Mcf) at the end of filling, and also stores it in the storage device 88 as actual performance data in association with the data of the filling date and time.

[0095] Thus, by repeatedly filling hydrogen into a large number (Japanese: unspecified majority) of unspecified FCVs 200, a plurality of actual performance data are accumulated in the storage device 88. As a result, the storage device 88 stores a plurality of past actual performance data obtained by corresponding the final measured filling amount Mmf, the final calculated filling amount Mcf, and the final filling amount error ΔMf. Here, the case of storing the final filling amount error ΔMf as a plurality of error values is shown.

[0096] As the average error calculation process (S132), the average error calculation unit 93 reads the final filling amount error ΔMf of each past hydrogen filling accumulated in the storage device 88, and calculates the average filling amount error ΔMave = ΣΔMf / number of fillings.

[0097] As the difference calculation process (S134), the error difference calculation unit 94 calculates the difference Mx between the statistical value of a plurality of error values based on a plurality of past actual performance data and the error value of the current hydrogen filling, that is, the error difference Mx. Specifically, the error difference calculation unit 94 calculates the error difference Mx by subtracting the current final filling amount error ΔMf from the average filling amount error ΔMave.

[0098] As a determination process (S136), the determination unit 95 compares the statistical value of multiple error values based on multiple past actual data stored in the storage device 88 with the error value at the end of the filling of hydrogen this time, determines whether there is a failure in the flowmeter 37, and outputs the result.

[0099] In the present embodiment, it is determined whether there is a failure in the flowmeter 37 according to whether the error difference Mx is within the allowable range. Specifically, the determination unit 95 determines whether the error difference Mx is within the range of not less than the lower limit allowable value β1 and not more than the upper limit allowable value β2. When the error difference Mx is not within the range of not less than the lower limit allowable value β1 and not more than the upper limit allowable value β2 (S136: "No"), the process proceeds to the alarm output process (S138). If the error difference Mx is within the range of not less than the lower limit allowable value β1 and not more than the upper limit allowable value β2 (S136: "Yes"), this process ends.

[0100] As an alarm output process (S138), when it is determined that there is a failure in the flowmeter 37, the output unit 74 outputs an alarm indicating the failure of the flowmeter 37 to the dispenser 30 during the filling of hydrogen. As an example of the alarm, an alarm lamp 34 indicating the failure of the flowmeter 37 lights up in the dispenser 30.

[0101] In addition, in the above example, as the statistical value of multiple error values based on multiple past actual data, the average filling amount error ΔMave is used, but it is not limited thereto. It may be, for example, the median instead of the average value.

[0102] In addition, each value of the lower limit allowable values α1, β1 and the upper limit allowable values α2, β2 may be set appropriately. Since the calculated filling amount obtained by the PVT method has the above-mentioned deviation caused by the expansion of the fuel tank 202, the difference between the measured filling amount and the calculated filling amount obtained by the PVT method is usually not zero, but there is a specified offset amount. Each value of the lower limit allowable values α1, β1 and the upper limit allowable values α2, β2 may be set in consideration of this point.

[0103] In addition, it may be as Figure 5 shown, instead of the above-mentioned determination process (S118) and alarm output process (S120), the determination process (S119), alarm output process (S121), determination process (S122) and alarm output process (S123) are implemented as a modification. Similarly, it may be as Figure 6 shown, instead of the above-mentioned determination process (S136) and alarm output process (S138), the determination process (S140), alarm output process (S141), determination process (S142) and alarm output process (S143) are implemented as a modification.

[0104] As the determination step (S119), the determination unit 90 determines whether the filling amount error ΔM at the current time point is equal to or greater than the lower limit allowable value α1. When the filling amount error ΔM is equal to or greater than the lower limit allowable value α1 (S119: "Yes"), it proceeds to the determination step (S122). When the filling amount error ΔM is not equal to or greater than the lower limit allowable value α1 (S119: "No"), it proceeds to the alarm output step (S121).

[0105] As the alarm output step (S121), when the filling amount error ΔM is not equal to or greater than the lower limit allowable value α1, during the hydrogen filling period, the output unit 74 outputs an alarm 1 indicating a failure of the flowmeter 37 to the dispenser 30. As an example of the alarm, an alarm lamp 34 indicating a failure of the flowmeter 37 lights up in the dispenser 30.

[0106] As the determination step (S122), the determination unit 90 determines whether the filling amount error ΔM is equal to or less than the upper limit allowable value α2. When the filling amount error ΔM is equal to or less than the upper limit allowable value α2 (S122: "Yes"), it proceeds to the determination step (S126). When the filling amount error ΔM is not equal to or less than the upper limit allowable value α2 (S122: "No"), it proceeds to the alarm output step (S123).

[0107] As the alarm output step (S123), when the filling amount error ΔM is not equal to or less than the upper limit allowable value α2, during the hydrogen filling period, the output unit 74 outputs an alarm 2 indicating a failure of the flowmeter 37 to the dispenser 30. As an example of the alarm, an alarm lamp 35 indicating a failure of the flowmeter 37 lights up in the dispenser 30.

[0108] As described above, in the determination process during the filling period, when the filling amount error ΔM is not equal to or less than the upper limit allowable value α2, as a cause, either or both of a failure of the flowmeter 37 and a leak in the pipe from the flowmeter 37 to the fuel tank 202 can be considered. On the other hand, when the filling amount error ΔM is not equal to or greater than the lower limit allowable value α1, it can be determined that the flowmeter 37 has failed. Therefore, by dividing the determination process with the upper and lower limits and separating the contents of the alarms, the failure location can be easily determined.

[0109] Similarly, as Figure 6 shown, as the determination step (S140), the determination unit 95 determines whether the calculated error difference Mx is equal to or greater than the lower limit allowable value β1. If the error difference Mx is equal to or greater than the lower limit allowable value β1 (S140: "Yes"), it proceeds to the determination step (S142). When the error difference Mx is not equal to or greater than the lower limit allowable value β1 (S140: "No"), it proceeds to the alarm output step (S141).

[0110] As an alarm output process (S141), when the error difference Mx is not equal to or greater than the lower limit allowable value β1, during the hydrogen filling period, the output unit 74 outputs an alarm 1 indicating a failure of the flowmeter 37 to the dispenser 30. As an example of the alarm, an alarm lamp 34 indicating a failure of the flowmeter 37 lights up in the dispenser 30.

[0111] As a determination process (S142), the determination unit 95 determines whether the calculated error difference Mx is equal to or less than the upper limit allowable value β2. If the error difference Mx is equal to or less than the upper limit allowable value β2 (S142: "Yes"), the process ends. When the error difference Mx is not equal to or less than the upper limit allowable value β2 (S142: "No"), the process proceeds to the alarm output process (S143).

[0112] As an alarm output process (S143), when the error difference Mx is not equal to or less than the upper limit allowable value β2, during the hydrogen filling period, the output unit 74 outputs an alarm 2 indicating a failure of the flowmeter 37 to the dispenser 30. As an example of the alarm, an alarm lamp 35 indicating a failure of the flowmeter 37 lights up in the dispenser 30.

[0113] As described above, in the determination process at the end of filling, when the error difference Mx is not equal to or less than the upper limit allowable value β2, as a cause, either or both of a failure of the flowmeter 37 and a leak in the pipe from the flowmeter 37 to the fuel tank 202 can be considered. On the other hand, when the error difference Mx is not equal to or greater than the lower limit allowable value β1, it can be determined that the flowmeter 37 has failed. Therefore, by dividing the determination process with the upper and lower limits and separating the contents of the alarm, the failure location can be easily determined.

[0114] In addition, due to the above-described filling operation, the hydrogen filling amounts of the accumulators 10, 12, and 14 decrease. Therefore, next, the pressure recovery mechanism 104 restores the pressure of the accumulators 10, 12, and 14. The pressure recovery mechanism 104 includes a compressor 40 and valves 21, 23, 25, etc. First, the system control unit 58 selects a hydrogen supply source connected to the suction side of the compressor 40 from a magazine, an intermediate accumulator, a hydrogen trailer, or a hydrogen production device (all not shown). Then, under the control of the system control unit 58, the pressure recovery control unit 61 controls the pressure recovery mechanism 104 to restore the pressure of the accumulators 10, 12, and 14.

[0115] Specifically, the operation is performed as follows. The pressure accumulators of the respective pressure accumulators for filling the fuel tank 202 may also perform pressure recovery during filling. However, since the time to recover to the specified pressure is insufficient, pressure recovery must also be performed after filling. The switching is performed in the order of the first pressure accumulator, the second pressure accumulator, and the third pressure accumulator. Therefore, first, the pressure of the pressure accumulator 10 as the first pressure accumulator is recovered. The valve control unit 60 opens the valve 21 from the state where the valves 21, 23, and 25 are closed.

[0116] Then, the compressor control unit 62 drives the compressor 40, compresses the hydrogen at a low pressure (e.g., 0.6 MPa) from the hydrogen supply source and sends it out, and fills the hydrogen until the pressure of the pressure accumulator 10 reaches the specified pressure P0 (e.g., 82 MPa), thereby recovering the pressure of the pressure accumulator 10.

[0117] Next, the valve control unit 60 closes the valve 21 and instead opens the valve 23. Then, the compressor control unit 62 drives the compressor 40, compresses the hydrogen at a low pressure (e.g., 0.6 MPa) and sends it out, and fills the hydrogen until the pressure of the pressure accumulator 12 reaches the specified pressure P0 (e.g., 82 MPa), thereby recovering the pressure of the pressure accumulator 12.

[0118] Next, the valve control unit 60 closes the valve 23 and instead opens the valve 25. Then, the compressor control unit 62 drives the compressor 40, compresses the hydrogen at a low pressure (e.g., 0.6 MPa) and sends it out, and fills the hydrogen until the pressure of the pressure accumulator 14 reaches the specified pressure P0 (e.g., 82 MPa), thereby recovering the pressure of the pressure accumulator 14.

[0119] Through the above, when the next FCV 200 comes to the hydrogen refueling station 102, the supply of hydrogen can also be performed in the same manner.

[0120] As described above, according to the present embodiment, the accuracy of the flowmeter 37 can be continuously verified. Therefore, it is possible to avoid performing the filling operation in a state where the malfunctioning flowmeter 37 is used.

[0121] Next, another example of calculating the calculated filling amount Mc in the above-described filling amount error calculation step (S116) will be described. In the above-described filling amount error calculation step (S116), the capacity V of the fuel tank 202 used for calculating the calculated filling amount Mc is a specified value inherent to the FCV 200, and the expansion rate of the fuel tank 202 is not particularly considered. Therefore, the calculated filling amount obtained by the PVT method deviates due to the expansion of the fuel tank 202 as described above. Therefore, the difference between the measured filling amount and the calculated filling amount obtained by the PVT method is usually not zero, and there is a specified offset amount.

[0122] The inventors of the present application conducted in-depth research and learned that the deviation caused by the expansion of the fuel tank 202 is not always the same, and the offset varies according to the difference between the first pressure P1 at the start of filling and the second pressure P2 at the end of filling. Table 1 shows the filling data obtained during multiple hydrogen fillings at the hydrogen refueling station 102.

[0123] [Table 1]

[0124]

[0125] As the filling data, the metered filling amount Mm, the first pressure P1, the second pressure P2, the first temperature T1, and the second temperature T2 are shown. The second pressure P2 and the second temperature T2 are the data at the end of filling. Additionally, in the control circuit 100, the calculated filling amount Mc is calculated, and the filling amount error ΔM is calculated by subtracting the calculated filling amount Mc from the metered filling amount Mm. The percentage error shown in Table 1 is the value of 100×(filling amount error ΔM / metered filling amount Mm).

[0126] Figure 8 is a graph showing the relationship between the filling pressure difference and the filling amount error for each filling data in Table 1. Figure 8 The horizontal axis of the graph shown is the filling pressure difference [MPa], which is obtained by subtracting the first pressure P1 from the standard pressure Ps of the fuel tank 202 at the end of filling. As the standard pressure Ps, the average value of the second pressure P2 at the end of filling included in a plurality of filling data obtained in the past can be used. Additionally, the filling amount error with respect to the filling pressure difference calculated by assuming the average value of the second pressure P2 at the end of filling as the standard pressure Ps can be plotted as shown in Figure 8 shown, and then the standard pressure Ps can be corrected so that the coefficient of determination R of the approximate formula y 2 is close to 1. For the correction of the standard pressure Ps, a known fitting method or the like can be used. Since the standard pressure Ps may vary depending on the outside air temperature, the standard pressure Ps can also be statistically calculated by season according to different outside air temperatures. In the fuel tank in one example, the specific value of the standard pressure Ps is 78 [MPa]. Figure 8 The vertical axis of the graph shown is the filling amount error ΔM [kg].

[0127] As Figure 8 shown, the larger the filling pressure difference during filling, the larger the filling amount error ΔM becomes, and the relationship shown by the formula y is obtained, and there is a high correlation between the filling pressure difference and the filling amount error. Additionally, the formula y and the standard pressure Ps are values suitable for a certain type of fuel tank. If the formula y is statistically calculated according to the type of fuel tank or by vehicle model, it is possible to handle multiple FCVs 200 that come to the hydrogen refueling station 102.

[0128] Therefore, based on Figure 8 The result shown is that the calculation filling amount Mc is calculated using a value that takes into account the expansion rate of the tank as the capacity of the tank used in the PVT method. Specifically, when the standard capacity inherent to the tank is set to Vs and the expansion rate is set to Ex, the first function representing the first capacity V1 of the fuel tank 202 in the filling amount calculation before the start of filling is V1 = Vs + (Vs × Ex) × (P1 / Ps) 3 In the first function, the correction amount of the tank capacity corresponding to the expansion rate Ex is proportional to the cube of the first pressure P1. In addition, the second function representing the second capacity V2 of the fuel tank 202 in the filling amount calculation after the start of filling is V2 = Vs + (Vs × Ex) × (P2 / Ps) 3 In the second function, the correction amount of the tank capacity corresponding to the expansion rate Ex is proportional to the cube of the second pressure P2. In addition, the expansion rate Ex and the standard capacity Vs are, for example, as described above. Figure 8 The results shown are for reference and are set according to the type of the fuel tank 202, and are stored in advance in the storage device 80. In addition, instead of setting the first function and the second function as numerical expressions, they may be stored in advance in the storage device 80 as a table corresponding to parameters such as the first pressure P1 and the second pressure P2 of the fuel tank. In addition, the second function may be V2 = Vs + (Vs × Ex) × (P2 / Ps) 1 In other words, in the second function, the correction amount of the tank capacity corresponding to the expansion rate Ex may be proportional to the second pressure P2.

[0129] Next, a flow meter failure determination method using the first volume V1 and the second volume V2 in consideration of the expansion rate of the fuel tank 202 is described. In addition, the outline of the hydrogen filling method including the determination method is the same as that described above. Figure 5 , Figure 6 The flowcharts shown are substantially the same, but the difference is that the first capacity V1 and the second capacity V2 in consideration of the expansion rate of the fuel tank 202 are used in the process of calculating the filling amount Mc used in the filling amount error calculation step ( S116 ).

[0130] Specifically, the flowmeter failure determination method according to this embodiment includes the following steps: using the flowmeter 37 to measure the filling amount of hydrogen filled into the fuel tank 202 (measured filling amount Mm) (S114); obtaining information on the pressure P and temperature T of the fuel tank 202 (S102); based on the obtained pressure P and temperature T and the capacity V of the fuel tank 202 considering the expansion rate Ex of the fuel tank 202, calculating the filling amount of hydrogen filled into the fuel tank 202 (calculated filling amount Mc) (S112); and using the error value (filling amount error ΔM) between the measured filling amount (measured filling amount Mm) and the calculated filling amount (calculated filling amount Mc) to determine whether there is a failure in the flowmeter 37 (S118).

[0131] Thus, in the step of calculating the filling amount (S112), when calculating the calculated filling amount Mc based on the information on the pressure P, temperature T, and capacity V of the fuel tank 202, the expansion rate Ex of the tank is considered, so the accuracy of the calculated filling amount Mc is improved. In other words, the filling amount error ΔM between the measured filling amount Mm and the calculated filling amount Mc becomes smaller, and in addition, the deviation becomes smaller, so the accuracy of the failure determination of the flowmeter 37 is improved. The filling amount error ΔM can also be calculated at any time after the filling starts. The filling amount error ΔM can also be calculated at the end of filling, and the appropriateness of the filling amount error ΔM can be evaluated at the end of filling. By evaluating the appropriateness of the filling amount error ΔM at the end of filling, it is possible to determine whether the filling amount of hydrogen is correctly measured each time. In addition, the filling amount error ΔM can also be calculated during the filling process before the end of filling, and the appropriateness of the filling amount error ΔM during the filling process can be evaluated. By evaluating the appropriateness of the filling amount error ΔM during the filling process, it is possible to detect defects occurring during the filling process as early as possible.

[0132] The flowmeter failure determination method according to this embodiment includes an alarm output step (S120, S121, S123) for outputting the determined result. In the above example, the alarm lamp is lit, but the type of alarm is not limited to this. In the alarm output step, a signal for causing the notification unit (display panel, sound output, alarm lamp, etc.) of the dispenser 30 equipped with the flowmeter 37 to operate can also be output. In the alarm output step, a signal for notifying a monitor or a monitoring device monitoring at a remote location via a network can also be output.

[0133] The operation filling amount Mc is calculated by Mc = N2 - N1, where the first weight N1 = ρ(P1, T1) × V1 is calculated based on the first pressure P1, the first temperature T1, and the first capacity V1 of the fuel tank 202 before the start of filling, and the second weight N2 = ρ(P2, T2) × V2 is calculated based on the second pressure P2, the second temperature T2, and the second capacity V2 of the fuel tank 202 after the start of filling (S112). As described above, the first capacity V1 and the second capacity V2 of the fuel tank 202 can be calculated using the first function and the second function represented by the mathematical formula stored in the storage device 80. Thus, the failure determination can be performed by a simple operation based on the information from the pressure gauge 206 and the thermometer 207 of the fuel tank 202.

[0134] Here, the first function is different from the second function. In a situation where the pressure in the fuel tank 202 is relatively low before the start of filling, the capacity considering the expansion rate of the fuel tank 202 can be calculated with high precision using the first function. On the other hand, in a situation where the pressure in the fuel tank 202 is relatively high after the start of filling, the capacity considering the expansion rate of the fuel tank 202 can be calculated with high precision using the second function. That is, in the first function, the tank capacity corresponding to the expansion rate is corrected based on the first pressure P1, and in the second function, the tank capacity corresponding to the expansion rate is corrected based on the second pressure P2. Therefore, compared with the case where the correction amount corresponding to the expansion rate is assumed to be constant regardless of the pressure in the tank, the capacity of the fuel tank 202 can be calculated with high precision. In addition, by substituting the correction function considering the expansion rate into the calculation formula for the operation filling amount Mc, the filling amount error ΔM can be calculated more appropriately for each filling, so that the failure determination of the flowmeter 37 can be simply performed in a short time. In other words, even without accumulating a plurality of past actual data required for the calculation of the average filling amount error ΔMave, the failure determination of the flowmeter 37 can be performed with high precision.

[0135] For the first pressure P1, a non-linear first function (V1 = V + (V × Ex) × (P1 / Ps) 3) Calculate the first capacity V1 before the start of filling. As a reason for such a preferred function, the inventors of the present application focused on the following situation: in a situation where the filling amount of the fuel tank 202 is large (a situation where the difference between the first pressure P1 and the second pressure P2 is large), the deviation between the metered filling amount Mm and the calculated filling amount Mc (that is, the filling amount error ΔM) is large. The first pressure P1 of the fuel tank 202 depends on the consumption amount of hydrogen corresponding to the driving distance of the FCV 200 that comes to the hydrogen refueling station 102, so the deviation corresponding to the situation is large. On the other hand, the deviation corresponding to the situation of the second pressure P2 of the fuel tank 202 is small. Therefore, the situation where the filling amount of the fuel tank 202 is large can be said to be a situation where the first pressure P1 of the fuel tank 202 is small. As a first function considering the first pressure P1, by using a non-linear function for the information on the pressure in the tank (first pressure P1) obtained, compared with the case where the expansion rate is assumed to increase in proportion to the pressure in the tank, the capacity of the fuel tank 202 can be calculated with high precision. In particular, it is effective in the case where the first pressure P1 is small and the filling amount is large.

[0136] On the other hand, as the second function considering the second pressure P2, either a non-linear function or a linear function can be used for the pressure in the tank (second pressure P2) obtained. Compared with the first pressure P1, the deviation corresponding to the situation of the second pressure P2 at the end of filling is small. Therefore, whether the value of (P2 / Ps) is cubed for correction or the value of (P2 / Ps) is corrected to the first power, the filling amount error ΔM2 can be calculated with high precision. Among them, if evaluated using actual data, the following result is obtained: it is more preferable to correct to the first power with the second function considering the second pressure P2 at the end of filling. In addition, compared with the end of filling, the deviation corresponding to the situation of the second pressure P2 during filling is large. Therefore, when calculating the second weight N2 during filling, it may be desirable to use a non-linear function that corrects the value of (P2 / Ps) to the third power.

[0137] The control circuit 100 (specifically, the receiving unit 52) can also obtain information related to the type of the fuel tank 202 from the FCV 200. The control circuit 100 can also obtain information related to the vehicle model from the FCV 200 to determine the type of the fuel tank 202 corresponding to the vehicle model. A table corresponding the vehicle model and the type of the fuel tank may be stored in the storage device 80 in advance. The first function and the second function related to the first capacity V1 or the second capacity V2 can also be set according to the type of the fuel tank 202. Thereby, when filling hydrogen into the fuel tanks of various vehicle models, the failure determination of the flow meter 37 can be performed.

[0138] In this way, according to the fault determination method according to the present embodiment, it is possible to verify the accuracy of the dispenser 30 in the hydrogen refueling station 102, more specifically, the flowmeter 37. In addition, without shutting down the hydrogen refueling station 102, it is possible to continuously verify the accuracy of the flowmeter 37 every time hydrogen is filled into the FCV 200.

[0139] In addition, the hydrogen filling device 500 according to the present embodiment includes: a metering machine (dispenser 30) that uses a flowmeter 37 to measure the filling amount (metered filling amount Mm) of hydrogen filled into the fuel tank 202 of the vehicle; an acquisition unit (reception unit 52) that acquires information on the pressure P and temperature T of the fuel tank 202; a filling amount calculation unit 87 that calculates, based on the acquired pressure P and temperature T and the capacity V of the fuel tank 202 taking into account the expansion rate Ex of the fuel tank 202, the filling amount (calculated filling amount Mc) of hydrogen filled into the fuel tank 202 from the metering machine (dispenser 30); and a determination unit 90 that determines whether there is a fault in the flowmeter 37 using the error value (filling amount error ΔM) between the filling amount (metered filling amount Mm) measured by the flowmeter 37 and the calculated filling amount (calculated filling amount Mc).

[0140] As described above, the present invention has been described with reference to the above embodiments. However, the present invention is not limited to the above embodiments, and embodiments obtained by appropriately combining and replacing the structures of the embodiments are also included in the present invention. In addition, based on the knowledge of those skilled in the art, it is possible to appropriately reorganize the combinations and processing sequences in the embodiments, make various design changes to the embodiments, etc. Embodiments to which such changes are applied can also be included in the scope of the present invention.

[0141] Industrial Applicability

[0142] The present invention relates to a technique for determining a fault in a metering machine included in a hydrogen filling device.

[0143] Description of Reference Numerals

[0144] 10, 12, 14: Accumulators; 30: Distributor; 34, 35: Alarm lights; 37: Flowmeter; 39: Display panel; 40: Compressor; 43: Control circuit; 50: Communication control circuit; 51: Memory; 52: Receiver; 54: Target pressure / temperature calculation unit; 58: System control unit; 64: Distributor control unit; 67: Distributor information receiver; 74: Output unit; 76: Monitor; 80: Storage device; 84: Storage device; 85: Gas weight calculation unit; 86: Judgment unit; 87: Filling amount calculation unit; 88: Storage device; 89: Filling amount error calculation unit; 90, 91: Judgment units; 92: Recording / calculation unit; 94: Error difference calculation unit; 95: Judgment unit; 96: Setting unit; 100: Control circuit; 101: Multi-stage accumulator; 102: Hydrogen refueling station; 200: FCV; 202: Fuel tank; 204: On-vehicle unit; 206: Pressure gauge; 207: Thermometer; 500: Hydrogen filling system.

Claims

1. A method for determining a flowmeter fault, characterized in that, Comprising the following steps: Using a flowmeter to measure the filling amount of hydrogen filled into the fuel tank of an automobile; Obtaining information on the pressure and temperature of the fuel tank; Based on the obtained pressure and temperature and the capacity of the fuel tank taking into account the expansion rate of the fuel tank, calculating the filling amount of hydrogen filled into the fuel tank; And Using the error value between the measured filling amount and the calculated filling amount to determine whether there is a fault in the flowmeter.

2. The flowmeter fault determination method according to claim 1, characterized in that Further comprising the following steps: Based on the first pressure, first temperature and first capacity of the fuel tank before the start of filling, calculating the first weight of hydrogen in the fuel tank before the start of filling; And Based on the second pressure, second temperature and second capacity of the fuel tank after the start of filling, calculating the second weight of hydrogen in the fuel tank after the start of filling, wherein the calculated filling amount is calculated using the first weight and the second weight.

3. The flowmeter fault determination method according to claim 2, characterized in that the first capacity is calculated using the expansion rate and the first pressure, and the second capacity is calculated using the expansion rate and the second pressure.

4. The flowmeter fault determination method according to claim 2 or 3, characterized in that the first capacity is calculated using a non-linear first function for the first pressure, the second capacity is calculated using a linear or non-linear second function for the second pressure.

5. The flowmeter fault determination method according to claim 4, characterized in that further comprising a step of determining the type of the fuel tank, wherein the first function and the second function are set according to the type of the fuel tank.

6. A hydrogen filling device, characterized in that, Comprising: A meter, which uses a flowmeter to measure the filling amount of hydrogen filled into the fuel tank of an automobile; An acquisition unit, which acquires information on the pressure and temperature of the fuel tank; A filling amount calculation unit, which calculates the filling amount of hydrogen filled into the fuel tank from the meter based on the obtained pressure and temperature and the capacity of the fuel tank taking into account the expansion rate of the fuel tank; And A determination unit, which uses the error value between the filling amount measured by the flowmeter and the calculated filling amount to determine whether there is a fault in the flowmeter.

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