JP2010255809A - Liquefied gas filling system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce impact through a water hammer phenomenon when finishing filling of liquefied gas. <P>SOLUTION: The filling control unit 140 of a control circuit 90 has a valve opening control means 141, a liquid level position discriminating means 142 and a valve closing control means 143. The valve opening control means 141 starts the filling of the liquified gas to a fuel tank 30 by opening a first opening-closing valve V1, a third opening-closing valve V5 and a second opening-closing valve V4 through a filling starting signal. The liquid level position discriminating means 142 discriminates whether or not the liquid level of the fuel tank 30, based on liquid level detecting data, reaches a predetermined position lower than the excessive filling preventive position, by receiving the liquid level detecting data detected by a liquid level detecting means 190. The valve closing control means 143 reduces a filling flow rate to the fuel tank 30 by the throttling valve opening of the first opening-closing valve V1 or the second opening-closing valve V4 to the valve closing side or closing the valve, when discriminating that the liquid level of the fuel tank reaches the predetermined position. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a liquefied gas filling system, and more particularly to a liquefied gas filling system that efficiently fills a fuel tank with liquefied gas.

  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 filling system for filling the liquefied gas, the liquefied gas storage tank, which is the storage source of the liquefied gas, and the filled container communicate with each other through two piping paths of a filling line and a pressure equalizing line. A method of filling liquefied gas well is performed (see, for example, Patent Document 1).

  FIG. 1 is a system diagram of a liquefied gas filling system using a conventional filling method. The pressure equalization filling method shown in FIG. 1 is a filling method particularly suitable for filling liquefied gas such as propane or DME, which has a large increase in saturated vapor pressure accompanying a temperature rise.

  As shown in FIG. 1, the liquefied gas filling system 10 includes a liquefied gas storage tank 20, a liquefied gas filling pipe path (filling line) 40, and a gas phase region pressure equalizing pipe 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 filling pipe 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 liquid phase side connection port 32 of the fuel tank 30 filled with the liquefied gas. 34. The gas phase region 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 filling piping path 40 is connected to the fuel tank 30 via the dispenser 60. A pump 70 serving as a pressurizing unit that pumps the liquefied gas is provided at a portion that communicates between the liquefied gas storage tank 20 and the dispenser 60. In the liquefied gas filling system of the pressure equalization method using the liquefied gas filling piping path 40 and the gas phase region pressure equalizing piping path 50, the liquefied gas is filled into the fuel tank 30 from the liquefied gas filling piping path 40, and By filling the vapor in the upper space (gas phase region) in the fuel tank 30 into the gas phase region of the liquefied gas storage tank 20 from the gas phase region equalizing piping path 50, it becomes possible to fill the liquefied gas at a large flow rate. Become.

  Further, the fuel tank 30 is provided with an overfill prevention valve 31 comprising a float valve that closes when the liquid level reaches a predetermined height position in order to prevent overfilling due to the rise in the liquid level. This overfill prevention valve 31 is connected to the tip of the liquefied gas filling pipe path 40 and is closed when the liquid level of the fuel tank 30 reaches a predetermined height position (overfill prevention position) at which the fuel tank 30 is fully filled. To do.

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

  The positive displacement flow meter 64 measures the flow rate of the liquefied gas filled by the liquefied gas filling pipe 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, it is possible to calculate the filling amount of the liquefied gas 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 rotating shaft.

  The filling connection coupling 34 is provided at the tip end (the other end) of the filling hose 42 constituting the liquefied gas filling 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 region pressure equalizing pipe path 50 drawn from the dispenser 60. The vehicle 80 on which the fuel tank 30 is mounted has a manual on-off valve V2 that opens or closes the liquid-phase side connection port 32 and a manual opening and closing that opens or closes the gas-phase side connection port 36. A valve V3 is provided.

  Here, the connection ports 32 and 36 open the internal passage when the connection couplings 34 and 38 are connected to the connection ports 32 and 36, while the internal passages when the connection couplings 34 and 38 are disconnected. It has a valve mechanism that closes (opening).

  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 region pressure equalizing piping 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 so that the filling pressure pressurized by the pump 70 exceeds the saturated vapor pressure of the liquefied gas so that the liquefied gas filled by the liquefied gas filling pipe path 40 is not vaporized in the positive displacement flow meter 64. It is set to open when the set value is exceeded.

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

  Upon completion of filling, the worker presses a filling stop switch button 96 provided on the dispenser 60 to turn it on. The control circuit 90 stops the pump 70 by the filling 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) filled in the fuel tank 30 as the filling amount, and stores the filling amount as the calculation result. At the same time, the filling amount is displayed on the flow rate display 92.

  In this liquefied gas filling 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 by the gas phase region equalizing piping path 50 before the start of filling, the liquefied gas storage tank The pressure difference between the fuel tank 20 and the fuel tank 30 is eliminated, and the pressure for filling the discharge pressure of the pump 70 can be effectively utilized.

  Further, liquid filling is performed by the discharge pressure of the pump 70, and vapor in the fuel tank 30 having a volume equal to the filling amount moves to the liquefied gas storage tank 20 via the gas phase region 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 filling flow rate in the process of filling the fuel tank 30 with the liquefied gas in the liquefied gas storage tank 20 is prevented.

  The filling of the liquefied gas is completed by closing the valve by detecting the predetermined filling amount of the overfilling prevention valve 31 provided in the fuel tank 30.

JP 2000-291889 A

  However, in the above-described conventional liquefied gas filling system, when the overfilling prevention valve 31 of the fuel tank 30 is closed due to rising of the liquid level due to filling of the liquefied gas, an impact due to a so-called water hammer phenomenon occurs. As a result, there is a risk of causing a failure of each device that performs the filling control arranged in the liquefied gas filling piping path 40.

  As a method for mitigating the impact caused by the so-called water hammer phenomenon, for example, it is conceivable to reduce the filling flow rate of the liquefied gas before the overfilling prevention valve 31 is closed. Since it is not known how the liquid surface position changes from the relationship between the remaining amount and the filling flow rate, it is unclear at what timing the filling flow rate of the liquefied gas should be reduced. For example, if the timing for reducing the filling flow rate is delayed, it is impossible to eliminate the impact caused by the so-called water hammer phenomenon, and if the timing for reducing the filling flow rate is too fast, the filling time for the small flow rate becomes longer and the fuel tank There is a problem that the completion of filling 30 is delayed.

  Then, in view of the said situation, this invention aims at providing the liquefied gas filling system which solved the said subject.

In order to solve the above problems, the present invention has the following means.
(1) The present invention includes a fuel tank filled with liquefied gas, an overfill prevention valve that closes when the liquid level of the fuel tank reaches an overfill prevention position, and a liquid level of the fuel tank. A vehicle having a liquid level detection means for detecting the position and a transmission means for transmitting the liquid level detection data detected by the liquid level detection means, a liquefied gas storage tank in which liquefied gas is stored, and one end of the liquefied gas A liquefied gas filling path connected to the liquid phase region of the gas storage tank, the other end connected to the liquid phase region of the fuel tank, one end connected to the gas phase region of the liquefied gas storage tank, and the other end A gas phase region equalizing path connected to the gas phase region, and pressurization for supplying the liquefied gas in the liquefied gas storage tank to the fuel tank via the liquefied gas filling channel by pressurizing the liquefied gas Means and a charge disposed in the liquefied gas filling path On-off valve, a pressure equalizing on-off valve arranged in the gas-phase region equalizing path, a receiving means for receiving liquid level detection data transmitted by the transmitting means, and a liquefied gas in the liquefied gas storage tank A filling start operation unit operated when starting filling the fuel tank, and a control means for controlling a filling amount of the liquefied gas filled in the fuel tank,
The control means includes
A valve opening control means for opening the filling on-off valve and the pressure equalizing on-off valve in response to a filling start signal from the filling start operating section to start filling the fuel tank with liquefied gas; and the liquid level detecting means. Liquid level position determination means for receiving the detected liquid level detection data and determining whether or not the liquid level of the fuel tank based on the liquid level detection data has reached a predetermined position lower than the overfilling prevention position; When the liquid level position determining means determines that the liquid level of the fuel tank has reached the predetermined position, at least one of the filling on-off valve and the pressure equalizing on-off valve is opened. And a valve closing control means for restricting the degree to the valve closing side and reducing the filling flow rate into the fuel tank.
(2) The valve closing control means closes the pressure equalizing on / off valve when a fuel tank filling amount based on the liquid level detection data becomes less than a predetermined value.

  According to the present invention, the liquid level detection data detected by the liquid level detection means is received, and it is determined that the liquid level of the fuel tank based on the liquid level detection data has reached a predetermined position lower than the overfill prevention position. In this case, the overfill prevention valve of the fuel tank is closed to reduce the filling flow rate to the fuel tank by reducing the opening of at least one of the filling on-off valve and the pressure equalizing on-off valve to the valve closing side. It is possible to reduce the impact due to the impact received by each device that performs filling control by reducing the impact due to the so-called water hammer phenomenon caused by the valve operation.

  Further, according to the present invention, when the amount that can be charged into the fuel tank becomes less than a predetermined amount, the pressure equalizing on / off valve is closed, so that the pressure in the gas phase region gradually increases with liquid filling, The filling flow rate is gradually reduced without controlling the valve opening as compared with the case of stopping the filling, so that the impact caused by the so-called water hammer phenomenon can be reduced and the valve control can be simplified. .

It is a systematic diagram of the liquefied gas filling system using the conventional filling system. It is a systematic diagram which shows one Example of the liquefied gas filling system by this invention. It is a flowchart for demonstrating the control processing which a control circuit 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 filling 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 filling 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 filling piping path 40 disposed inside the dispenser 60. 110, and a third on-off valve V5 (filling on-off valve) comprising an electromagnetic valve arranged in a bypass pipe 44 that bypasses the upstream side and the downstream side of the first on-off valve V1 (filling on-off valve). Have

  Further, the first on-off valve V1 and the third on-off valve V5 are connected in parallel to the liquefied gas filling 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 chargeable flow rate Q5 is smaller than the flow rate Q1 of the first on-off valve V1 (Q5 < Q1).

  Therefore, at the start of filling of the liquefied gas into the fuel tank 30, only the third on-off valve V5 is opened and filled with 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. It increases to (Q5 + Q1), and filling is performed with the maximum flow rate. When the filling is stopped, the first opening / closing valve V1 is closed first, the filling flow rate is reduced from the maximum flow rate (Q5 + Q1) to the small flow rate Q5, and the third opening / closing valve V5 is closed after a predetermined time has elapsed. As a result, the filling 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 filling 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.

  Further, the fuel tank 30 of the vehicle 80 is provided with a liquid level detecting means 190 including a liquid level sensor. The liquid level detection data measured by the liquid level detection unit 190 is transmitted as a radio signal by the radio apparatus (transmission unit) 200, for example. In this embodiment, the maximum filling amount is a filling rate of 85% with respect to the entire volume of the fuel tank 30. Therefore, the liquid level detection means 190 outputs the liquid level detection signal L when the filling rate reaches 75%, and outputs the liquid level detection signal H when the filling rate reaches 85%. That is, the liquid level detection means 190 outputs the liquid level detection signal L when the liquid level of the fuel tank 30 reaches a predetermined position (filling rate 75%) lower than the overfill prevention position, and the liquid level detection signal L is output. When the surface reaches the overfilling prevention position (filling rate 85%), the liquid level detection signal H is output.

  The control circuit 90 receives the liquid level detection data of the fuel tank 30 transmitted from the radio device 200 of the vehicle 80 by the radio device (reception means) 210 provided on the upper part of the dispenser 60, and converts the received liquid level detection data into the received liquid level detection data. Based on this, the opening degree of each of the on-off valves V1, V4, V5 is adjusted, and a control signal is output to control to open or close the valves.

  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, reads each control program, each data and parameter stored in the storage unit 180, and performs arithmetic processing. .

  Further, the control circuit 90 controls the opening and closing of the first on-off valve V1, the third on-off valve V5 as the filling on-off valve, and the second on-off valve V4 as the pressure equalizing on-off valve, thereby controlling the fuel tank 30. A filling control unit 140 that performs filling control of the liquefied gas, and a filling amount calculation unit 150 that calculates the filling amount of the liquefied gas filled in the fuel tank 30 by integrating the flow rate pulses output from the positive displacement flow meter 64. Have.

  Further, the filling control unit 140 includes a valve opening control unit 141, a liquid level position determination unit 142, and a valve closing control unit 143. The valve opening control means 141 is operated by the first on-off valve V1, the third on-off valve V5 (filling on-off valve), and the second on-off valve V4 in response to a filling start signal from the filling start switch button 94 (filling start operation unit). The pressure equalizing on / off valve is opened stepwise to start filling the fuel tank 30 with liquefied gas, and the gas filling flow rate is switched from a small flow rate to a large flow rate. The liquid level position determination unit 142 receives the liquid level detection data detected by the liquid level detection unit 190, and the liquid level of the fuel tank 30 based on the liquid level detection data is lower than the overfilling prevention position (a predetermined position). It is determined whether or not the filling rate has reached 75%.

  When the liquid level position determining unit 142 determines that the liquid level of the fuel tank 30 has reached a predetermined position (filling rate 75%) lower than the overfill preventing position, the valve closing control unit 143 A control signal for restricting the valve opening degree of the on-off valve V1 or the second on-off valve V4 to the valve closing side or for closing the valve is output, and the filling flow rate to the fuel tank 30 is decreased. In this way, by reducing the filling flow rate to the fuel tank 30, the overfilling prevention valve 31 is closed when the liquid level of the fuel tank 30 reaches the overfilling prevention position (filling rate 85%). The impact due to the so-called water hammer phenomenon can be reduced.

  Further, the valve closing control means 143 closes the pressure equalizing second on-off valve V4 when the fillable amount into the fuel tank 30 based on the liquid level detection data becomes less than a predetermined value (filling rate 75%). A control signal for outputting is output. As described above, when the second on-off valve V4 is closed at the filling rate of 75% of the fuel tank 30, vapor in the gas phase region of the fuel tank 30 is not discharged. For this reason, in the fuel tank 30 thereafter, the pressure in the gas phase region gradually increases as the liquid level in the liquid phase region rises due to the filling of the liquefied gas. The pressure difference from the filling pressure gradually decreases. Therefore, since the filling flow rate of the liquefied gas gradually decreases, the impact caused by the so-called water hammer phenomenon caused by the closing operation of the overfilling prevention valve 31 can be reduced.

  Here, in the liquefied gas filling system 100, an operation procedure and control processing when the fuel tank 30 is filled with liquefied gas will be described.

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

  Next, the liquefied gas filling control process executed by the control circuit 90 of the dispenser 60 will be described. FIG. 3 is a flowchart for explaining the liquefied gas filling control process executed by the control circuit 90 of the dispenser 60. In the control circuit 90, reception processing of the liquid level detection data detected by the liquid level detection means 190 of the vehicle 80 is also performed in parallel, but the description thereof is omitted.

  As shown in FIG. 3, when the charging start switch button 94 of the dispenser 60 is turned on in S11, the control circuit 90 proceeds to S12 and opens the second on-off valve V4 (pressure equalizing on-off valve). Valve (opening control means). Then, it progresses to S13, and while starting the pump 70, the liquefied gas of the liquefied gas storage tank 20 is pressurized, and the liquefied gas filling piping path | route 40 can be filled with the liquefied gas.

  Further, in S14, the third on-off valve V5 as the filling sub on-off valve is opened (valve opening control means). Since the flow path of the third on-off valve V5 is small, filling of the liquefied gas at a small flow rate into the fuel tank 30 is started by opening the third on-off valve V5.

  In next S15, it is checked whether or not the elapsed time from the start of filling has reached a predetermined time set in advance. In S15, when the elapsed time from the start of filling does not reach the predetermined time set in advance, the process proceeds to S16, and the filling rate detected by the liquid level detecting means 190 of the vehicle 80 is 75% (relative to the volume of the fuel tank 30). It is checked whether or not the liquid level detection signal L of the ratio of the filling amount is input via the wireless devices 200 and 210 (liquid level position determining means). In S16, when the liquid level detection signal L with a filling rate of 75% is not input by the liquid level detection means 190, the process returns to S15 and the processes of S15 and S16 are repeated.

  In S15, when the elapsed time from the start of filling reaches a predetermined time set in advance, the process proceeds to S17, and the first on-off valve V1 as the main on-off valve for filling is opened (valve opening control means). ). Thereby, the filling flow rate to the fuel tank 30 is increased, and the liquefied gas is filled with a large flow rate.

  Subsequently, in S18, it is checked whether or not a liquid level detection signal L with a filling rate of 75% detected by the liquid level detection means 190 of the vehicle 80 is input via the wireless devices 200 and 210 (liquid level position determination). means). In S18, the liquefied gas is filled with a large flow rate until the liquid level detection signal L with a filling rate of 75% is input, and the processes in S17 and S18 are repeated.

  In S18, when the liquid level detection signal L having a filling rate of 75% is input, the process proceeds to S19, where the second pressure equalizing second on-off valve V4 is closed (valve closing control means). Since the vapor in the gas phase region of the fuel tank 30 is not discharged by closing the second on-off valve V4 with the filling rate of 75% in the fuel tank 30 in this way, the liquefaction in the fuel tank 30 thereafter As the liquid level in the liquid phase region rises due to gas filling, the pressure in the gas phase region gradually increases. Therefore, the pressure difference from the filling pressure of the liquefied gas gradually decreases due to the pressure increase in the fuel tank 30, and the filling flow rate of the liquefied gas is gradually reduced. Therefore, the filling flow rate of the liquefied gas automatically decreases as the filling rate increases. In S19, the valve opening degree of the second on-off valve V4 may be switched to the valve closing side (for example, the valve opening degree is changed from 100% to 20% to 5%).

  When the liquid level detection signal L having a filling rate of 75% is input in S16 described above, the liquid level is filled at a predetermined filling position (filling rate of 75%) by filling with a small flow rate only by the third on-off valve V5. Since the liquid level position has been reached, the processes of S17 and S18 are omitted, and the process of S19 is performed. That is, when the liquid level position of the liquefied gas remaining in the fuel tank 30 is close to a predetermined filling position (liquid level position with a filling rate of 75%), the filling rate is 75% even when only the third on-off valve V5 is filled. The liquid level detection signal L is detected by the liquid level detection means 190. Also in this case, as in the case of S18 described above, the vapor in the gas phase region of the fuel tank 30 is not discharged by closing the second on-off valve V4. Therefore, in the fuel tank 30, as the liquid level in the liquid phase region rises due to the filling of the liquefied gas, the pressure in the gas phase region gradually increases and the pressure difference from the filling pressure of the liquefied gas gradually decreases. Thus, the filling flow rate of the liquefied gas is gradually reduced. Therefore, as the filling rate increases, the filling flow rate of the liquefied gas automatically decreases.

  In the next S20, the refillable amount of the fuel tank 30 is set to the remaining filling rate of 10% with respect to the total volume of the fuel tank 30 (the remaining refillable amount when the maximum filling rate of the fuel tank 30 is 85%). Since it has decreased, the first on-off valve V1 is closed (valve closing control means). As a result, only the third on-off valve V5 is filled with a small flow rate from a filling rate of 75% to a full filling rate of 85%.

  Thus, since the filling flow rate is reduced to a small flow rate, for example, even if the overfill prevention valve 31 is closed during filling with the small flow rate of only the third on-off valve V5, so-called water hammer (water hammer). Impact from the phenomenon is alleviated. In S20, the valve opening degree of the first on-off valve V1 may be switched to the valve closing side (for example, the valve opening degree is changed from 100% to 20% to 5%).

  Subsequently, in S21, a liquid level detection signal H having a filling rate of 85% (full filling amount with respect to the volume of the fuel tank 30) detected by the liquid level detecting means 190 of the vehicle 80 is input via the radio devices 200 and 210. Check whether or not. In S21, the liquefied gas is charged until the liquid level detection signal H with the filling rate of 85% detected by the liquid level detecting means 190 is input. The fuel tank 30 is provided with an overfill prevention valve 31. The liquid level height reaches a liquid level with a filling rate of 85%, and the overfill prevention valve 31 is closed. In this case, since the filling flow rate to the fuel tank 30 has already been reduced, the impact caused by the so-called water hammer phenomenon caused by the closing operation of the overfill prevention valve 31 is mitigated.

  In S21, when the liquid level detection signal H having a filling rate of 85% is input, the filling rate of the fuel tank 30 has reached the maximum value. The valve V5 is closed to complete filling with a small flow rate (valve closing control means). When the overfill prevention valve 31 is not yet closed, the third on-off valve V5 is closed before the overfill prevention valve 31. Even in this case, since the filling flow rate to the fuel tank 30 has already been reduced, the impact caused by the so-called water hammer phenomenon caused by the closing operation of the third on-off valve V5 is alleviated.

  As described above, when the liquid level of the fuel tank 30 reaches the overfilling prevention position with the filling rate of 85% and the overfilling prevention valve 31 or the third on-off valve V5 is closed, the pressure equalizing second on-off valve is already provided. Since V4 is closed and the filling flow rate is gradually reduced, the impact caused by the so-called water hammer phenomenon when the overfill prevention valve 31 or the third on-off valve V5 is closed is suppressed. Thus, it is possible to reduce the influence of the impact received by each device that performs filling control.

  In the above embodiment, the filling method in which the liquefied gas is pressurized by the pump and filled into the fuel tank has been described as an example. However, the present invention is not limited to this. For example, pressurizing means other than the pump (for example, the liquefied gas storage tank 20 Of course, a method of using the potential energy by installing at a high place, a filling method in which the liquefied gas storage tank 20 is heated to increase the pressure in the gas phase region and filled by a pressure difference, or the like may be used.

  In the above embodiment, the liquid level detection means 190 outputs the liquid level detection signal L when the filling rate reaches 75%, and outputs the liquid level detection signal H when the filling rate reaches 85%. When the liquid level detection signal L is input from the liquid level detection means 190, the control circuit 90 fills the fuel tank 30 by controlling the valve openings of the on-off valves V1, V4, V5. Although the flow rate is reduced, the liquid level detection means 190 of the present invention is replaced with one that outputs a liquid level detection signal corresponding to the filling rate, and the liquid level input from the liquid level detection means 190 in the control circuit 90 The filling rate is determined from the detection signal, and when it is determined that the filling rate has reached 75% and 85%, the opening of each of the on-off valves V1, V4, V5 is controlled to thereby fill the fuel tank 30 with a filling flow rate. You may make it squeeze.

  In the above embodiment, when the filling rate detected by the liquid level detecting means 190 reaches 75%, the pressure equalizing second on-off valve V4 and the first on-off valve V1 are closed or opened. The filling flow rate into the fuel tank 30 is reduced by reducing the valve, but either the second on-off valve V4 or the first on-off valve V1 may be closed or the valve opening may be reduced. good.

  Further, in the above embodiment, when the filling rate detected by the liquid level detecting means 190 reaches 75%, the pressure equalizing second on-off valve V4 and the first on-off valve V1 are closed or opened. The filling flow rate into the fuel tank 30 is reduced by narrowing down, but for example, the filling flow rate into the fuel tank 30 may be reduced when the filling rate reaches 65%. 30 when the gas filling into the gas tank 30 is completed (when the liquid level of the fuel tank 30 reaches the overfilling prevention position where the filling rate is 85% and the overfilling prevention valve 31 or the third on-off valve V5 is closed). May be adjusted so that the pressure equalizing second on-off valve V4 and the first on-off valve V1 are closed or the valve opening is reduced.

30 Fuel tank 32 Liquid phase side connection port 36 Gas phase side connection port 40 Liquefied gas filling piping route 44 Bypass piping 50 Gas phase region equalization piping route 60 Dispenser 64 Positive displacement flow meter 66 Back pressure valve 70 Pump 80 Vehicle 90 Control circuit 94 Fill start switch button 100 Liquefied gas filling system 180 Storage unit 190 Liquid level detection means 200 Wireless device (transmission means)
210 Wireless device (receiving means)
141 Valve opening control unit 142 Liquid level position determining unit 143 Valve closing control unit 140 Filling control unit 150 Filling amount calculation unit

Claims (2)

A fuel tank filled with liquefied gas; an overfill prevention valve that closes when the liquid level of the fuel tank reaches an overfill prevention position; and a liquid level that detects a liquid level height position of the fuel tank A vehicle having detection means and transmission means for transmitting the liquid level detection data detected by the liquid level detection means;
A liquefied gas storage tank in which liquefied gas is stored;
A liquefied gas filling path having one end connected to the liquid phase region of the liquefied gas storage tank and the other end connected to the liquid phase region of the fuel tank;
A gas phase region 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 fuel tank;
Pressurizing means for supplying the liquefied gas in the liquefied gas storage tank to the fuel tank by pressurizing the liquefied gas;
An on-off valve for filling disposed in the liquefied gas filling path;
A pressure equalizing on-off valve arranged in the gas phase region equalizing path;
Receiving means for receiving the liquid level detection data transmitted by the transmitting means;
A filling start operation unit operated when starting to fill the fuel tank with the liquefied gas in the liquefied gas storage tank;
Control means for controlling the filling amount of the liquefied gas filled in the fuel tank,
The control means includes
A valve opening control means for opening the filling on-off valve and the pressure equalizing on-off valve in accordance with a filling start signal from the filling start operation section to start filling the fuel tank with liquefied gas;
The liquid level detection data detected by the liquid level detection means is received, and it is determined whether or not the liquid level of the fuel tank based on the liquid level detection data has reached a predetermined position lower than the overfill prevention position. Liquid level position determining means;
When the liquid level position determining means determines that the liquid level of the fuel tank has reached the predetermined position, at least one of the filling on-off valve and the pressure equalizing on-off valve is opened. A valve closing control means for restricting to a valve closing side and reducing a filling flow rate to the fuel tank;
A liquefied gas filling system comprising:   2. The valve closing control means closes the pressure equalizing on / off valve when a fuel tank filling amount based on the liquid level detection data becomes less than a predetermined value. Liquefied gas filling system.

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