JP5243982B2 - Liquefied gas supply system - Google Patents

Description

  The present invention relates to a liquefied gas supply system, and more particularly to a liquefied gas supply system that can more accurately measure the amount of liquefied gas supplied to a container.

  As a liquefied gas used as a fuel for vehicles such as automobiles, for example, LPG (Liquid Petroleum Gas) mainly composed of butane / propane, DME (diesel fuel having a high oxygen content and no black smoke) Dimethyl ether). Since this type of liquefied gas can be liquefied by compressing gaseous fuel, a liquid phase region and a gas phase region coexist in the tank.

  As the liquefied gas supply system for supplying the liquefied gas, the liquefied gas storage system, which is a storage source of the liquefied gas, and the container to be supplied communicate with each other through two piping paths of a supply line and a pressure equalization line. A method of supplying a liquefied gas well is performed (for example, see Patent Document 1).

  FIG. 1 is a system diagram of a liquefied gas supply system using a conventional supply method. As shown in FIG. 1, the liquefied gas supply system 10 includes a liquefied gas storage tank 20, a liquefied gas supply piping path (supply line) 40, and a gas phase pressure equalizing piping path (pressure equalizing line) 50. . The liquefied gas storage tank 20 is a large tank with a large capacity for storing liquefied gas.

  The liquefied gas supply piping path 40 has one end connected to the liquid phase region of the liquefied gas storage tank 20 and the other end connected to the connection port 32 of the fuel tank (supplied container) 30 to which the liquefied gas is supplied. A coupling 34 is provided. The gas phase equalizing pipe path 50 has a pressure equalizing connection coupling 38 having one end connected to the gas phase region of the liquefied gas storage tank 20 and the other end connected to the gas phase side connection port 36 of the fuel tank 30.

  The liquefied gas supply piping path 40 is connected to the fuel tank 30 via the dispenser 60. A pump 70 serving as a supply means for pressure-feeding the liquefied gas is provided at a portion communicating between the liquefied gas storage tank 20 and the dispenser 60.

  In addition, a separator 62, a positive displacement flow meter 64, a back pressure valve 66, and a first on-off valve V1 (a liquefied gas supply on-off valve) including an electromagnetic valve are provided inside the housing of the dispenser 60. Yes. The separator 62 is a gas-liquid separator that separates bubbles from the liquefied gas supplied by the liquefied gas supply piping path 40.

  The positive displacement flow meter 64 measures the flow rate of the liquefied gas supplied through the liquefied gas supply piping path 40 and outputs a flow rate pulse corresponding to the measured volume flow rate. The positive displacement flow meter 64 is a so-called piston flow meter. For example, as shown in JP-A-8-94408, four pistons reciprocate with a phase difference of 90 °. Rotational force generated by the reciprocating motion of the piston is transmitted to the rotary shaft, and a flow rate pulse generator that generates a flow rate pulse proportional to the volume corresponding to the rotational angle of the rotary shaft (volume of liquefied gas pushed out by the movement of the piston) Have Therefore, the supply amount of the liquefied gas can be calculated by integrating the flow rate pulse proportional to the volume flow rate of the volume discharged by the piston according to the rotation angle of the rotation shaft.

  The supply connection coupling 34 is provided at the tip (the other end) of the supply hose 42 constituting the liquefied gas supply piping path 40 drawn from the dispenser 60. Further, the pressure equalizing connection coupling 38 is provided at the tip (the other end) of the pressure equalizing hose 52 constituting the gas phase pressure equalizing pipe path 50 drawn from the dispenser 60. The vehicle 80 on which the fuel tank 30 is mounted includes a manual on-off valve V2 that opens or closes the connection port 32, and a manual on-off valve V3 that opens or closes the gas-phase side connection port 36. Is provided.

  Here, when the connection structure of the connection ports 32 and 36 connects the connection couplings 34 and 38 to the connection ports 32 and 36, the internal passage is opened. When having a valve structure that closes the passage (opening), the on-off valve V2 and on-off valve V3 are not necessarily required.

  The back pressure valve 66 has a pressure equalized in the gas phase region introduced as a back pressure through a back pressure pipe 68 branched from the gas phase pressure equalizing pipe path 50, and is pumped from the pressure equalized pressure. The valve is configured to open when the hydraulic pressure pressurized by 70 increases.

  That is, the back pressure valve 66 is configured such that the supply pressure pressurized by the pump 70 exceeds the saturated vapor pressure of the liquefied gas so that the liquefied gas supplied by the liquefied gas supply piping path 40 does not vaporize in the positive displacement flow meter 64. It is set to open when the set value is exceeded.

  Here, the flow rate calculation after the supply of the liquefied gas by the liquefied gas supply system 10 configured as described above will be described.

  The supply of the liquefied gas is terminated by closing the valve by detecting a predetermined supply amount of the oversupply prevention valve in the fuel tank 30. When the supply is finished, the worker presses a supply stop switch button 96 provided on the dispenser 60 to turn it on. The control circuit 90 stops the pump 70 by the supply stop signal and closes the first on-off valve V1. Next, the control circuit 90 reads the flow rate pulse output from the positive displacement flow meter 64 to calculate the flow rate of the liquefied gas (liquid) supplied to the fuel tank 30 as the supply amount, and stores the supply amount of the calculation result. At the same time, the supply amount is displayed on the flow rate display 92.

  In this liquefied gas supply system 10, since the gas phase region of the liquefied gas storage tank 20 and the gas phase region of the fuel tank 30 are communicated with each other by the gas phase equalizing piping path 50 before the supply is started, the liquefied gas storage tank The pressure difference between the fuel tank 20 and the fuel tank 30 is eliminated, and the pressure for supplying the discharge pressure of the pump 70 can be effectively utilized.

  In addition, liquid supply is performed by the discharge pressure of the pump 70, and vapor in the fuel tank 30 having a volume equal to the supply amount moves to the liquefied gas storage tank 20 via the gas phase equalizing pipe path 50. Therefore, vapor liquefaction in the gas phase region of the fuel tank 30 does not occur, and an increase in internal pressure due to vapor liquefaction latent heat does not occur. Therefore, a decrease in the supply flow rate in the process of supplying the liquefied gas in the liquefied gas storage tank 20 to the fuel tank 30 is prevented.

  The pressure equalizing supply method shown in FIG. 1 is a supply method particularly suitable for supplying a liquefied gas such as propane or DME, which has a large increase in saturated vapor pressure accompanying a temperature increase.

Japanese Patent Application No. 11-99258

  In the liquefied gas supply system of the above equalized pressure supply system, as the liquefied gas is supplied into the fuel tank 30, the upper space (gas phase region) becomes narrower as the liquid level in the fuel tank 30 rises. Vapor (vaporized liquefied gas) existing in the space moves to the liquefied gas storage tank 20 via the gas-phase pressure equalizing pipe path 50, and the supply amount of the liquefied gas actually supplied to the fuel tank 30 is accurately determined. There was a problem that it could not be measured.

  In order to solve the above problem, it is also conceivable to provide a flow meter in the gas phase pressure equalizing pipe path 50 to measure the flow rate of the vapor. However, there is a possibility that the pressure will drop due to the pipe resistance in the gas phase pressure equalizing piping path 50 and the vapor may be liquefied, or the vapor and liquid may be mixed, and the liquefied gas flowing through the flow meter It is not known whether the property is gas, liquid, or a mixed state thereof. For this reason, the problem that it is very difficult to measure the flow volume of the liquefied gas which moves to the liquefied gas storage tank 20 with the said flow meter arises.

  In view of the above circumstances, an object of the present invention is to provide a liquefied gas supply system capable of accurately measuring the supply amount of liquefied gas actually supplied.

In order to solve the above problems, the present invention has the following means.
(1) The present invention of claim 1 is a liquefied gas storage tank in which liquefied gas is stored;
A liquefied gas supply path having one end connected to the liquid phase region of the liquefied gas storage tank and the other end connected to the supply container;
A supply device for sequentially supplying the liquefied gas to the supply container, a flow meter, and a liquefied gas supply on-off valve;
A gas phase equalizing path in which one end is connected to the gas phase region of the liquefied gas storage tank and the other end is connected to the gas phase region of the supplied container;
A pressure equalization path opening / closing valve provided in the gas phase pressure equalization path;
A pressure detector disposed between the pressure equalizing path opening / closing valve and the supply container among the gas phase pressure equalizing path;
A liquefied gas supply system comprising a control circuit,
The control circuit includes:
A supply control unit that performs supply control of the liquefied gas to the supply container by opening and closing the liquefied gas supply opening and closing valve and the pressure equalizing path opening and closing valve;
A supply amount calculation unit that calculates the supply amount of the liquefied gas supplied to the supply container by integrating the flow rate pulses output from the flow meter,
The supply amount calculation unit reads the pressure in the supply container before supplying the liquefied gas to the supply container as the pre-supply pressure from the pressure detector, and the supply after the supply to the supply container is completed. Supply of the liquefied gas to the supplied container calculated from the pre-supply pressure, the post-supply pressure, and the flow rate measured by the flow meter as the post-supply pressure after the pressure in the supplied container is read from the pressure detector The vapor movement amount flowing through the gas phase equalizing pipe path is calculated from the amount, and the liquefied gas supply supplied to the supply container by subtracting the vapor movement amount from the supply amount measured by the flow meter It is characterized by calculating a quantity.
(2) In the present invention of claim 2, the supply amount calculation unit is
A pre-supply pressure reading means for reading a pressure value measured by the pressure detector as a pre-supply pressure in a state where the pressure equalizing path opening / closing valve is closed;
The liquefied gas for calculating the supply amount of the liquefied gas supplied to the supply container by the flow rate pulse output from the flow meter by opening the pressure equalizing path open / close valve and the liquefied gas supply open / close valve. Supply amount calculation means;
When the pressure equalizing path opening / closing valve and the liquefied gas supply opening / closing valve are closed and the supply of the liquefied gas to the supply container is completed, the pressure value measured by the pressure detector is supplied after the supply pressure. After-supply pressure reading means,
A vapor movement amount calculating means for calculating a vapor movement amount based on the pre-supply pressure, the post-supply pressure, and the supply amount;
Liquefied gas supply amount correction means for calculating a liquefied gas supply amount to the supply container by subtracting the vapor movement amount from the supply amount;
It is characterized by having.

  According to the present invention, the pressure of the liquefied gas supplied to the supply container flows from the pre-supply pressure, the post-supply pressure, and the supply amount of the liquefied gas calculated from the flow rate measured by the flow meter. By calculating the amount of vapor movement, the amount of vapor (vaporized liquefied gas) moving from the supplied container to the liquefied gas storage tank when supplying the liquefied gas to the supplied container can be obtained and measured by a flow meter. By subtracting the amount of vapor movement from the supplied amount and calculating the supply amount of the liquefied gas supplied to the supplied container, it is supplied to the supplied container without providing a vapor flow meter for the vapor pressure equalization piping path. It is possible to accurately determine the liquid supply amount.

It is a systematic diagram of the liquefied gas supply system using the conventional supply system. It is a systematic diagram which shows one Example of the liquefied gas supply system by this invention. 4 is a main flowchart for explaining a liquefied gas supply control process 1 executed by a control circuit 90 of the dispenser 60; 3 is a flowchart for explaining a liquefied gas supply amount calculation process executed by a control circuit 90; 6 is a flowchart for explaining supply amount correction calculation processing executed by a control circuit 90; It is a systematic diagram which shows the modification of the liquefied gas supply system by this invention. It is a main flowchart for demonstrating the liquefied gas supply control process 2 which the control circuit 90 of a modification performs.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

  FIG. 2 is a system diagram showing an embodiment of the liquefied gas supply system according to the present invention. In FIG. 2, the same parts as those shown in FIG. As shown in FIG. 2, the liquefied gas supply system 100 is a temperature detector that detects the temperature T1 of the liquefied gas flowing into the positive displacement flow meter 64 in the liquefied gas supply piping path 40 disposed in the dispenser 60. 110 and a third on-off valve V5 (for liquefied gas supply) comprising an electromagnetic valve disposed in a bypass line 44 that bypasses the upstream and downstream sides of the first on-off valve V1 (liquefied gas supply on-off valve). Open / close valve). Further, the gas-phase-portion pressure equalizing pipe path 50 includes a second on-off valve V4 made of an electromagnetic valve, a backflow prevention valve 120 disposed between the liquefied gas storage tank 20 and the second on-off valve V4, A pressure detector 130 disposed between the two on-off valves V4 and the fuel tank (supplied container) 30 is provided.

  The backflow prevention valve 120 is opened when the vapor generated in the fuel tank 30 is moved to the liquefied gas storage tank 20 when the pressure of the fuel tank 30 is higher than that of the liquefied gas storage tank 20. When the pressure of the storage tank 20 is higher than that of the fuel tank 30, the valve is closed due to the pressure difference to prevent vapor backflow.

  The first on-off valve V1 and the third on-off valve V5 are connected in parallel to the liquefied gas supply piping path 40, and are controlled to open or close individually with a time difference. Further, since the flow path (port diameter) of the third on-off valve V5 is smaller than that of the first on-off valve V1, the supplyable flow rate Q5 is smaller than the flow rate Q1 of the first on-off valve V1 (Q5 < Q1).

  Therefore, when the supply of liquefied gas to the fuel tank 30 is started, only the third on-off valve V5 is opened and supplied at a small flow rate Q5, and the flow rate is increased when the first on-off valve V1 is opened after a predetermined time has elapsed. The supply is increased to (Q5 + Q1), and the supply at the maximum flow rate is performed. When the supply is stopped, the first on-off valve V1 is closed first, the supply flow rate is reduced from the maximum flow rate (Q5 + Q1) to the small flow rate Q5, and the third on-off valve V5 is closed after a predetermined time has elapsed. As a result, the supply flow rate becomes zero. Therefore, the flow rate control similar to that of the two-stage on-off valve that gradually increases or decreases the supply flow rate by shifting the opening and closing timings of the first on-off valve V1 and the third on-off valve V5 by a predetermined time. Is done.

  The control circuit 90 controls the fuel tank 30 by opening and closing the first on-off valve V1, the third on-off valve V5 as the liquefied gas supply on-off valve, and the second on-off valve V4 as the pressure equalizing path on-off valve. The supply control unit 140 that controls the supply of liquefied gas to the fuel, and the supply amount calculation unit 150 that calculates the supply amount of the liquefied gas supplied to the fuel tank 30 by integrating the flow rate pulses output from the positive displacement flow meter 64. And have.

  The supply amount calculation unit 150 reads the pressure value measured by the pressure detector 130 with the second opening / closing valve V4 closed as the pre-supply pressure (pre-supply pressure reading means), and the second open / close Procedure for calculating the supply amount of the liquefied gas supplied to the fuel tank 30 by opening the valve V4 and the first and third on-off valves V1 and V5 from the flow rate pulse output from the positive displacement flow meter 64 ( Liquefied gas supply amount calculation means).

  Further, the supply amount calculation unit 150 is configured to detect the pressure detector when the second on-off valve V4 and the first and third on-off valves V1, V5 are closed and the supply of the liquefied gas to the fuel tank 30 is completed. The procedure of reading the pressure value measured by 130 as the post-supply pressure (post-supply pressure reading means), and the procedure of calculating the vapor movement amount based on the pre-supply pressure, the post-supply pressure, and the supply amount (vapor movement amount calculation means) And a procedure (liquefied gas supply amount correcting means) for calculating the liquefied gas supply amount to the supply container by subtracting the vapor movement amount from the supply amount, and each procedure is executed.

  The control circuit 90 is connected to a storage unit 180 having storage means such as a magnetic disk device or an IC memory, for example, and reads each control program and each data and parameter stored in the storage unit 180 to perform arithmetic processing. To do.

  In addition, the storage unit 180 includes an integrated flow rate storage unit 182 that integrates and stores the flow rate pulses input from the positive displacement flow meter 64, and a constant temperature (in this embodiment, a reference temperature of 15) based on the temperature when the liquefied gas is supplied. A temperature integrated flow rate storage unit 184, a pressure-gas density table 186, and a correction coefficient table 188 are provided for the flow rate integrated value whose temperature is corrected to the volume of ° C).

  The fuel tank 30 is provided with a liquid level sensor 190. The liquid level detection signal measured by the liquid level sensor 190 is transmitted to the control circuit 90 via a cable or a connector, or transmitted to the control circuit 90 via a wireless device capable of wireless transmission, for example. And input to the control circuit 90.

  Here, in the liquefied gas supply system 100, an operation procedure and control processing when the liquefied gas is supplied to the fuel tank 30 will be described.

  As operations for supplying the liquefied gas to the vehicle 80, first, an operator connects the supply connection coupling 34 to the connection port 32 of the fuel tank 30, and further connects the pressure equalization connection coupling 38 to the fuel tank 30. Connect to the gas phase side connection port 36. Then, the worker opens the on-off valves V2 and V3. This completes the preparatory work before starting the supply of liquefied gas, confirms that there is no abnormality, and turns on the supply start switch button 94 of the dispenser 60.

  Next, the liquefied gas supply control process 1 executed by the control circuit 90 of the dispenser 60 will be described. FIG. 3 is a main flowchart for explaining a main control process executed by the control circuit 90 of the dispenser 60.

  As shown in FIG. 3, the control circuit 90 checks whether or not the supply start switch button 94 has been turned on by pressing the supply start switch button 94 in S11, and when the supply start switch button 94 is turned on, Proceed to S12. In S12, the detection value P11 before the start of supply detected by the pressure detector 130 is read and stored in the storage unit 180 (pre-supply pressure reading means). Subsequently, in the next S13, the read detection value P11 is stabilized. Check whether the sex is confirmed. In S13, the process waits until the detection value P11 before the supply is stabilized within a certain range. For example, it is monitored whether the fluctuation range of the detection value P11 is equal to or less than a predetermined value, or the fluctuation range of the detection value P11. It is monitored whether time has elapsed until the value becomes equal to or less than a predetermined value. In S13, if a pressure change occurs, the process returns to S12, the changed pressure is stored in the storage unit 180, and the detection value P11 is updated. By repeating the processes of S11 and S12 each time a pressure fluctuation is detected, a stable pre-supply pressure can be stored in the storage unit 180. As a result, the pressure value P11 stored in the storage unit 180 in S12 can be set as the pressure in the fuel tank 30 before the start of the supply of the liquefied gas.

  If it is confirmed in S13 that the detected value P11 is stable at a constant value, the process proceeds to S14. In S14, the 2nd on-off valve V4 provided in the gaseous-phase part pressure equalization piping path | route 50 is opened.

  As a result, the gas phase region of the liquefied gas storage tank 20 and the gas phase region of the fuel tank 30 communicate with each other, and the high pressure side vapor moves to the low pressure side. The vapor pressure is related to the temperature. For example, when the vehicle 80 receives high-temperature radiant heat from the road as in summer, the saturated vapor pressure of the fuel tank 30 becomes higher than the pressure of the liquefied gas storage tank 20. Yes. Therefore, when the second on-off valve V4 is opened, the vapor of the fuel tank 30 moves to the liquefied gas storage tank 20, and pressure equalization between the fuel tank 30 and the liquefied gas storage tank 20 is performed.

  In next S15, the detection value P11 before the start of supply after pressure equalization detected by the pressure detector 130 is read to confirm the stability of the detection value P11. That is, it is checked whether or not the pressure change ΔP1 per unit time of the detected value P1 is equal to or less than a preset set value ΔPs. The set value ΔPs can be changed to an arbitrary value.

  In S15, when the pressure change ΔP1 is equal to or smaller than the set value ΔPs (ΔP1 <ΔPs), it is determined that the detected value P11 is stable, and the process proceeds to S16 to start the pump 70. Subsequently, in S17, the third on-off valve V5 of the liquefied gas supply piping path 40 is opened (first stage valve opening). Thereby, supply of the liquefied gas in the liquefied gas storage tank 20 is started via the liquefied gas supply piping path 40 and the bypass piping 44. As described above, when the supply of the liquefied gas to the fuel tank 30 is started, the control circuit 90 performs the supply control of the fuel tank 30 by the supply control unit 140 and the supply amount of the liquefied gas by the supply amount calculation unit 150 described later. Perform arithmetic processing.

  Further, the back pressure valve 66 is opened when the supply pressure of the liquefied gas pressurized by the pump 70 as the supply means becomes higher than the pressure in the gas-phase part equalizing pipe path 50 (pressure in the fuel tank 30). To do. As a result, the liquefied gas in the liquefied gas storage tank 20 is pumped by the pump 70 and started to be supplied to the fuel tank 30 via the liquefied gas supply pipe path 40 and the bypass pipe 44 and is proportional to the flow rate from the positive displacement flow meter 64. The flow rate pulse Fn is output. Thereafter, supply control processing is performed by opening and closing each valve, and calculation processing of flow rate measurement values is performed in parallel processing.

  In next S18, it is checked whether or not a predetermined time N1 (for example, 1 to 2 seconds) set in advance has elapsed. In S18, when the predetermined time N1 elapses, the process proceeds to S19, where the first on-off valve V1 is opened (second stage valve opening). Thereby, the liquefied gas in the liquefied gas storage tank 20 pressurized by the pump 70 is supplied to the fuel tank 30 at the maximum flow rate (Q5 + Q1) via the liquefied gas supply piping path 40 and the bypass piping 44. In this embodiment, after the third on-off valve V5 is opened, the first on-off valve V1 is opened after a lapse of a predetermined time, whereby the supply pressure to the fuel tank 30 is increased stepwise. Thus, the burden on the piping system due to a sudden pressure rise can be reduced.

  In this embodiment, a pump is used as the supply means. However, the pressure in the gas phase section itself is increased or supplied, or a moving partition is provided in the gas phase section, and the liquefied gas storage tank 20 is partitioned by the moving partition. Alternatively, a high-pressure gas may be supplied to supply the liquefied gas in the liquefied gas storage tank 20 through the moving partition.

  In the next S20, it is checked whether or not a liquid level detection signal L with a supply rate of 75% is input from the liquid level sensor 190 of the fuel tank 30. In S20, when the liquid level detection signal L with the supply rate of 75% of the liquid level sensor 190 is input, the process proceeds to S21, and the first on-off valve V1 is closed (first stage valve closing). Thereby, the supply amount of the liquefied gas supplied to the fuel tank 30 is reduced to the small flow rate Q5 supplied via the bypass conduit 44.

  In the next S22, it is checked whether or not a liquid level detection signal H (first condition for stopping supply) having a supply rate of 85% is input from the liquid level sensor 190 of the fuel tank 30. In S22, the process of S22 is repeated until the liquid level detection signal H with a supply rate of 85% of the liquid level sensor 190 is input, and when the liquid level detection signal H is input, the process proceeds to the process of S23 described later. The supply of liquefied gas to the fuel tank 30 is stopped.

  In the present embodiment, the supply of liquefied gas is detected when it is detected that a liquid level detection signal H (first condition for stopping supply) having a supply rate of 85% is input from the liquid level sensor 190 of the fuel tank 30. However, it is not limited to this.

  For example, when the supply rate to the fuel tank 30 reaches near 85% and is provided in the fuel tank 30 and the fuel tank 30 is filled with a predetermined amount, the liquefied gas into the fuel tank 30 is supplied. The supply of liquefied gas to the fuel tank 30 becomes impossible by the operation of a valve (oversupply prevention valve or shutoff valve) that blocks supply. As a result, when it is detected that the flow rate output from the positive displacement flow meter 64 has become zero, it may be detected that the supply of the liquefied gas to the fuel tank 30 has ended. More specifically, when it is empirically known in advance that the cycle of the flow rate pulse output from the positive displacement flow meter 64 when supplying the liquefied gas to the fuel tank 30 is 1 second or less. By setting the predetermined time N2 to 1 second or longer, it is possible to detect when the supply is completed even if the liquid level detection signal H is not input from the liquid level sensor 190.

  In S22, when a liquid level detection signal having a supply rate of 85% from the liquid level sensor 190 is input, the fuel tank 30 is filled with liquefied gas (as a result of being supplied into the fuel tank 20, the fuel tank 20 And the process proceeds to S23 to close the third on-off valve V5 (second stage valve closing). As a result, the supply of the liquefied gas to the fuel tank 30 is stopped.

  In next S24, the pressure value P12 after the supply stop is read from the pressure detector 130 and stored in the storage unit 180 (post-supply pressure reading means), and then the process proceeds to S25 and the supply stop read from the pressure detector 130 is performed. It is confirmed whether or not the subsequent pressure value P12 is stabilized at a constant value. In S25, as in S13, the process waits until the detection value P12 before the start of supply stabilizes within a certain range. For example, it is monitored whether the fluctuation range of the detection value P12 has become a predetermined value or less. Alternatively, it is monitored whether the time until the fluctuation range of the detection value P12 becomes equal to or less than a predetermined value has elapsed. In S25, if a pressure change occurs, the process returns to S24, the changed pressure is stored in the storage unit 180, and the detection value P12 is updated. A stable post-supply pressure can be stored in the storage unit 180 by repeating the processes of S24 and S25 each time a pressure fluctuation is detected. As a result, the pressure value P12 stored in the storage unit 180 in S24 can be the pressure in the fuel tank 30 after the supply of the liquefied gas is completed.

  If it is confirmed in S25 that the detected value P12 is stable at a constant value, the process proceeds to S26. In S26, a supply completion process is performed. That is, in S26, the value of the calculation result obtained by subtracting the amount of vapor moved from the gas phase of the fuel tank 30 to the liquefied gas storage tank 20 from the supply amount to the fuel tank 30 measured by the positive displacement flow meter 64 is stored in the fuel tank 30. The supply amount of the supplied liquefied gas is read from the storage unit 180, and the read value of the supply amount is displayed on the flow rate display 92.

  Next, the liquefied gas supply amount calculation process executed by the control circuit 90 will be described with reference to FIG. Note that the liquefied gas supply amount calculation process shown in FIG. 4 is executed by outputting a flow rate pulse from the positive displacement flow meter 64 when the supply of the liquefied gas to the fuel tank 30 is started, and the positive displacement type when the liquefied gas supply is stopped. When a flow rate pulse is not output from the flow meter 64, a standby state is entered.

  In S31 of FIG. 4, it is checked whether or not the flow rate pulse Fn is input from the positive displacement flow meter 64. The flow rate pulse Fn of the positive displacement flow meter 64 indicates the flow rate of the liquefied gas corresponding to the volume pushed out by the reciprocating motion of the piston as described above. When the configuration of the positive displacement flow meter 64 is, for example, four pistons reciprocate with a phase difference of 90 °, a flow rate pulse corresponding to the flow rate (volume) obtained by adding the volumes according to the movement amounts of the pistons is output. .

  In S31, when the flow rate pulse Fn is input from the positive displacement flow meter 64, the process proceeds to S32, and the integrated flow rate (ΣFn) obtained by adding the flow rate pulse is stored in the integrated flow rate storage unit 182 provided in the storage unit 180 ( Liquefied gas supply amount calculation means).

  In the next S33, the liquid temperature (Tn) of the liquefied gas flowing through the liquefied gas supply piping path 40 measured by the temperature detector 110 is read.

  Subsequently, the process proceeds to S 34, and the volume conversion coefficient (αn) corresponding to the liquid temperature (Tn) of the liquefied gas supplied to the fuel tank 30 is read from the storage unit 180. In step S35, the flow rate pulse Fn is multiplied by a volume conversion coefficient (αn) to calculate a temperature corrected flow rate (Fn × αn).

  In the next S36, the temperature correction integrated flow rate (Σ (Fn × αn)) obtained by adding the temperature correction flow rate (Fn × αn) is stored in the temperature correction integrated flow rate storage unit 184 provided in the storage unit 180. . After this, the process returns to S31 again.

  As described above, when the flow rate pulse from the positive displacement flow meter 64 is input, the control circuit 90 executes the processing of S31 to S36 and sequentially updates the temperature correction integrated flow rate (Σ (Fn × αn)).

  Next, the supply amount correction calculation process executed by the control circuit 90 will be described with reference to FIG. Note that the supply amount correction calculation process shown in FIG. 5 is performed after the completion of supply in which the integrated flow rate of the liquefied gas is measured by the positive displacement flow meter 64 shown in FIG.

  In S41 shown in FIG. 5, the gas density ρ1 corresponding to the pressure P11 of the fuel tank 30 before supply is read from the pressure-gas density table (stores pressure-gas density data) 186 stored in the storage unit 180. Alternatively, an arithmetic expression stored in the storage unit 180 may be read, and the gas density ρ1 may be calculated by substituting the pressure P11 of the fuel tank 30 before supply into the arithmetic expression.

  In next S 42, the gas density ρ 2 corresponding to the pressure P 12 of the supplied fuel tank 30 is read from the pressure-gas density table (stores pressure-gas density data) 186 stored in the storage unit 180. Alternatively, an arithmetic expression stored in the storage unit 180 may be read, and the gas density ρ2 may be calculated by substituting the pressure P12 of the fuel tank 30 before supply into the arithmetic expression.

  In S43, the density ratio r = ρ2 / ρ1 between the gas density ρ1 and the gas density ρ2 obtained in S41 and S42 is calculated.

  Subsequently, the process proceeds to S44, and the correction coefficient f1 corresponding to the density ratio r is read from the correction coefficient table 188 of the storage unit 180.

In the next S45, the vapor movement amount ΔVG1 moved through the liquefied gas supply piping path 40 is calculated using the following equation (1). The vapor movement amount ΔVG1 is the amount of vapor moved from the gas phase region of the fuel tank 30 to the liquefied gas storage tank 20 via the liquefied gas supply piping path 40 (vapor moving amount calculating means).
ΔVG1 = f1 × ΣFn × ρ1 (1)
In S46, the vapor movement amount ΔVG1 is divided by the density γ of the reference temperature (15 ° C.) of the liquefied gas to be converted into a liquid amount ΔVL1 at the reference temperature (15 ° C.).

  Subsequently, the process proceeds to S47, in which the temperature-corrected integrated flow rate (Σ (Fn × αn)) stored in the temperature-corrected integrated flow rate storage unit 184 is read, and the liquid amount ΔVL1 is calculated from the temperature-corrected integrated flow rate (Σ (Fn × αn)). The actual supply amount V01 at the reference temperature (15 ° C.) supplied to the fuel tank 30 after subtraction is calculated (liquefied gas supply amount correcting means).

  As described above, ΔVL1 obtained by converting the amount of vapor moved from the gas phase region of the fuel tank 30 to the liquefied gas storage tank 20 into the liquid amount is subtracted from the supply amount (Σ (Fn × αn)) measured by the positive displacement flow meter 64. This V01 becomes the actual supply amount of the liquefied gas supplied to the fuel tank 30. Accordingly, in this embodiment, the vapor moved from the gas phase region of the fuel tank 30 to the liquefied gas storage tank 20 by performing the arithmetic processing of S41 to S47 without providing a flow meter in the liquefied gas supply piping path 40. The amount of vapor moved from the gas phase region of the fuel tank 30 to the liquefied gas storage tank 20 from the integrated flow rate (Σ (Fn × αn)) of the flow rate pulse measured by the positive displacement flow meter 64 can be calculated. By subtracting ΔVL1 converted into the liquid amount, the actual supply amount V01 supplied to the fuel tank 30 can be accurately obtained.

  Here, a modified example will be described.

  FIG. 6 is a system diagram showing a modification of the liquefied gas supply system according to the present invention. In FIG. 6, the same parts as those in FIG.

  As shown in FIG. 6, the liquefied gas supply system 200 according to the modified example has the bypass pipe 44, the third on-off valve V <b> 5, and the liquid level sensor 190 of the vehicle 80 deleted from the embodiment shown in FIG. 2. Yes. Further, the liquefied gas supply system 200 is provided with a supply stop switch button 96 for the operator to judge that the supply of the liquefied gas from the fuel tank 30 is completed and to stop the supply.

  Further, the fuel tank 30 is provided with a liquid level gauge 210 indicating the liquid level height (liquid level) of the supplied liquefied gas. When the operator performing the gas supply operation can confirm that the liquid level has reached the target supply position by the liquid level gauge 210 after starting the supply, the operator stops the supply of the liquefied gas by turning on the supply stop switch button 96. Stop supplying.

  FIG. 7 is a main flowchart for explaining the liquefied gas supply control process 2 executed by the control circuit 90 of the modification. In FIG. 7, the processing of S51 to S56 is the same as S11 to S16 of FIG. Hereinafter, processing different from that of the above embodiment will be described.

  In this modification, in S57, supply of the liquefied gas to the fuel tank 30 is started by opening the first on-off valve V1. The operator looks at whether or not the pointer of the level gauge 210 provided in the fuel tank 30 has reached the target supply position. When the pointer of the level gauge 210 reaches the target supply position, the supply stop switch The button 96 is turned on.

  In the next S58, it is checked whether or not the supply stop switch button 96 is turned on. When the supply stop switch button 96 is turned on in S58, the process proceeds to S59, and the first on-off valve V1 is closed. The subsequent processing of S60 to S62 is the same processing as the processing of S21 and S25 to S27 of FIG.

  Also in this modification, the liquefied gas supply amount calculation process shown in FIG. 4 and the supply amount correction calculation process shown in FIG. 5 are executed in the same manner. Therefore, in the present invention, the bypass pipe 44, the third on-off valve V5, and the liquid level sensor 190 of the vehicle 80 shown in FIG. 2 are not essential, and at least as shown in FIG. The first open / close valve V 1, the second open / close valve V 4, the positive displacement flow meter 64, the temperature detector 110, and the pressure detector 130 may be disposed in the gas phase equalizing pipe path 50.

  In this embodiment, the liquefied gas supply system for supplying the liquefied gas to the fuel tank of the vehicle has been described. However, the present invention is not limited to this, and is used in other devices (for example, a generator that uses the liquefied gas as fuel). Of course, the present invention is also applied to the case where the fuel tank is supplied.

  Moreover, in the said Example, although the case where the supply amount of liquefied gas was measured using a piston type flow meter was mentioned as an example, positive displacement flow meters (for example, a pair of elliptical gears are used as a rotor). A flow meter configured to be engaged, or a flow meter configured to combine a pair of eyebrows rotors) may be used.

  Of course, the flow rate of the liquefied gas can also be measured by a flow meter other than the positive displacement flow meter (for example, a turbine flow meter or a Coriolis mass flow meter). In addition, when using a Coriolis type | mold mass flowmeter for a flowmeter, what is necessary is just to consider that the flow volume measured with the said flowmeter is a mass flow volume which does not require temperature correction. That is, the vapor movement amount ΔVG1 flowing out from the fuel tank 20 is calculated from the integrated mass flow rate supplied to the fuel tank 20 in the vapor movement amount calculation process in S45 described above in consideration of the gas density in the fuel tank 20, and S46. The vapor movement amount ΔVG1 is used as the liquid amount ΔVL1 in S47, and the processes in S33 to S35 may be omitted. In this case, the mass flow rate stored in the integrated flow rate storage unit 182 and the temperature-corrected integrated flow rate storage unit 184 naturally has the same value. In this case, only the integrated flow rate storage unit 182 suffices. The part 184 can be omitted.

30 Fuel tank 40 Liquefied gas supply pipe path 44 Bypass pipe 50 Gas phase pressure equalizing pipe path 60 Dispenser 64 Volumetric flow meter 90 Control circuit 94 Supply start switch button 96 Supply stop switch button 100, 200 Liquefied gas supply system 110 Temperature Detector 120 Backflow prevention valve 130 Pressure detector 140 Supply control unit 150 Supply amount calculation unit 180 Storage unit 182 Integrated flow rate storage unit 184 Temperature correction integrated flow rate storage unit 186 Pressure-gas density table 188 Correction coefficient table 190 Liquid level sensor 210 Liquid Surface meter V1 First on-off valve V4 Second on-off valve V5 Third on-off valve

Claims (2)

A liquefied gas storage tank in which liquefied gas is stored;
A liquefied gas supply path having one end connected to the liquid phase region of the liquefied gas storage tank and the other end connected to the supply container;
A supply device for sequentially supplying the liquefied gas to the supply container, a flow meter, and a liquefied gas supply on-off valve;
A gas phase equalizing path in which one end is connected to the gas phase region of the liquefied gas storage tank and the other end is connected to the gas phase region of the supplied container;
A pressure equalization path opening / closing valve provided in the gas phase pressure equalization path;
A pressure detector disposed between the pressure equalizing path opening / closing valve and the supply container among the gas phase pressure equalizing path;
A liquefied gas supply system comprising a control circuit,
The control circuit includes:
A supply control unit that performs supply control of the liquefied gas to the supply container by opening and closing the liquefied gas supply opening and closing valve and the pressure equalizing path opening and closing valve;
A supply amount calculation unit that calculates the supply amount of the liquefied gas supplied to the supply container by integrating the flow rate pulses output from the flow meter,
The supply amount calculation unit reads the pressure in the supply container before supplying the liquefied gas to the supply container as the pre-supply pressure from the pressure detector, and the supply after the supply to the supply container is completed. Supply of the liquefied gas to the supplied container calculated from the pre-supply pressure, the post-supply pressure, and the flow rate measured by the flow meter as the post-supply pressure after the pressure in the supplied container is read from the pressure detector The vapor movement amount flowing through the gas phase equalizing pipe path is calculated from the amount, and the liquefied gas supply supplied to the supply container by subtracting the vapor movement amount from the supply amount measured by the flow meter A liquefied gas supply system characterized by calculating an amount. The supply amount calculation unit includes:
A pre-supply pressure reading means for reading a pressure value measured by the pressure detector as a pre-supply pressure in a state where the pressure equalizing path opening / closing valve is closed;
The liquefied gas for calculating the supply amount of the liquefied gas supplied to the supply container by the flow rate pulse output from the flow meter by opening the pressure equalizing path open / close valve and the liquefied gas supply open / close valve. Supply amount calculation means;
When the pressure equalizing path opening / closing valve and the liquefied gas supply opening / closing valve are closed and the supply of the liquefied gas to the supply container is completed, the pressure value measured by the pressure detector is supplied after the supply pressure. After-supply pressure reading means,
A vapor movement amount calculating means for calculating a vapor movement amount based on the pre-supply pressure, the post-supply pressure, and the supply amount;
Liquefied gas supply amount correction means for calculating a liquefied gas supply amount to the supply container by subtracting the vapor movement amount from the supply amount;
The liquefied gas supply system according to claim 1, comprising:

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