JPH09178094A - Gas supply device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten a charging time by compensating pressure shortage of a gas supply tank on an after stage through gas charging from a gas supply tank on a before stage. SOLUTION: This gas supply device 1 is constituted of a pressure generating unit 4, a dispenser unit 5, and a control device 6. A control program as a changeover timing change control means changing changeover timing for changing from a variable pressure gas accumulator 17 to a high pressure gas accumulator 18 according to the pressure of the high pressure gas accumulator 18 is stored in the memory 27 of the control device 6. Hence, when the pressure Pa of the high pressure gas accumulator 18 is low, the changeover timing is delayed by a time in response to the difference (Pa-Po) of the pressure Pa of the high pressure gas accumulator 18 and target charge pressure Po. Hereby, even when the pressure Pa of the high pressure gas accumulator 18 is low, a gas charging time can be prolonged by the variable pressure gas accumulator 17 so as to compensate pressure shortage of the high pressure gas accumulator 18, and as a result, the charging time can be shortened.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas supply device, and more particularly to a gas supply device configured to shorten a gas filling time for a tank to be filled.

[0002]

2. Description of the Related Art For example, as a gas supply device for supplying compressed natural gas (CNG) obtained by compressing natural gas to another tank (filled tank), a device as disclosed in Japanese Utility Model Publication No. 4-64699. There is. The device of this publication adopts a method of rapidly filling compressed gas, and a gas whose pressure is raised to a predetermined pressure or more by a compressor is temporarily stored in a variable pressure gas accumulator or a high pressure gas accumulator as a gas supply tank. The gas that has been stored and then stored in the variable pressure gas accumulator and the high pressure gas accumulator is gradually injected into the fuel tank of the automobile to be filled until the inside of the fuel tank reaches a predetermined pressure.

The amount of gas supplied to the fuel tank of an automobile is measured by a flow meter, and the total flow rate filled in the fuel tank can be known. The pressure filled in the fuel tank outputs a signal according to the pressure. It can be detected by a pressure transmitter. For example, the maximum pressure filled in the fuel tank is 20
If a 0 kgf / cm ^2, variable pressure gas accumulator, and the maximum pressure of the high pressure gas accumulator is set to 250 kgf / cm ^2. Therefore, the compressor compresses the city gas (about 5 to 8 kgf / cm ² ) supplied from the medium pressure line to bring the pressures of the variable pressure gas accumulator and the high pressure gas accumulator to the above set pressures.

An on-off valve consisting of a solenoid valve is provided in each gas supply system for supplying gas from the variable pressure gas accumulator and the high pressure gas accumulator. On the variable pressure gas accumulator side when the on-off valve provided in the gas supply system passage of the accumulator is opened and the fuel tank pressure reaches the specified pressure in the first stage or the flow rate decreases below the specified flow rate. The on-off valve is closed and the on-off valve provided in the gas supply system passage of the high-pressure gas accumulator is opened. By switching the gas accumulator on the supply side in this way, the pressure of the fuel tank of the automobile is raised to the target filling pressure, and when the fuel tank reaches the target filling pressure, the gas supply from the high pressure gas accumulator is stopped.

[0005]

However, in the conventional gas supply device, when the fuel tanks of a plurality of automobiles are continuously filled with gas, the gas compressed by the compressor is the variable pressure gas accumulator and the high pressure gas accumulator. It is necessary to start filling gas into the fuel tank when the pressure of the variable pressure gas accumulator and the high pressure gas accumulator does not reach the specified pressure (250 kgf / cm ² ) because the time for accumulating pressure in the container is not enough. Sometimes.

In this case, when the gas of the variable pressure gas pressure accumulator is supplied to the fuel tank and the pressure of the fuel tank reaches the specified pressure of the first stage, the gas supply source is changed from the variable pressure gas pressure accumulator to the high pressure gas pressure accumulator. Even if switched to, the supply flow rate of the gas supplied from the high-pressure gas accumulator is smaller than usual, so there is a problem that it takes time until the fuel tank pressure reaches the target filling pressure and the filling time must be extended. .

When a large vehicle having a large fuel tank capacity is continuously filled with gas, the pressures of the variable pressure gas accumulator and the high pressure gas accumulator are significantly reduced, and therefore the compressor is compressed. Even if the gas is accumulated in the variable pressure gas accumulator and the high pressure gas accumulator, the gas filling is started in a state where the pressure accumulating work is not in time and the specified pressure is not reached.
Even if the variable pressure gas accumulator is switched to the high pressure gas accumulator, the gas supply flow rate is not secured, and the filling pressure of the fuel tank does not reach the filling target pressure, resulting in insufficient filling.

Therefore, an object of the present invention is to provide a gas supply device which solves the above problems.

[0009]

In order to solve the above problems, the present invention has the following features. Claim 1
In the invention, the method of filling the filled tank from the gas supply tank of the latter stage after filling the filled tank from the gas supply tank of the former stage among the plurality of gas supply tanks storing the compressed gas In a gas supply device for switching the communication between the plurality of gas supply tanks and the tank to be filled to increase the pressure of the tank to be filled to a target filling pressure stepwise, switching from the gas supply tank in the previous stage to the gas supply tank in the latter stage It is characterized in that a switching timing change control means for changing the switching timing is provided.

Therefore, according to the first aspect, the switching timing for switching from the gas supply tank in the former stage to the gas supply tank in the latter stage can be changed, so that when the pressure in the latter gas supply tank is lower than the specified pressure. According to the pressure, it is possible to extend the gas filling time in the tank to be filled by the gas supply tank in the preceding stage. Therefore, the pressure shortage in the gas supply tank in the latter stage can be compensated by the gas filling from the gas supply tank in the former stage, and the filling time can be shortened.

According to the second aspect of the present invention, when the difference between the pressure of the rear gas supply tank and the target filling pressure is less than a predetermined value, the switching timing changing control means controls the switching to the rear gas supply tank. It is characterized by delaying the time according to the difference. Therefore, according to the second aspect, when the difference between the pressure in the rear gas supply tank and the target charging pressure is less than or equal to a predetermined value, the switching to the rear gas supply tank is delayed by a time corresponding to the pressure difference. When the pressure in the gas supply tank is lower than the permissible range, the switching to the gas supply tank in the subsequent stage can be delayed for a necessary time, and the filling time can be shortened.

Further, in the invention of claim 3, the switching timing changing control means obtains the switching flow rate from the difference between the pressure of the gas supply tank in the subsequent stage and the target filling pressure, and the flow rate from the gas supply tank in the preceding stage is switched. When the flow rate is lower than the flow rate, the gas supply tank is switched to the latter stage gas supply tank.

Therefore, according to the third aspect, when the flow rate from the front gas supply tank becomes equal to or lower than the switching flow rate according to the pressure difference, the gas supply tank is switched to the rear gas supply tank. If the flow rate cannot be secured because it is lower than the specified pressure, the gas filling time to the filled tank by the gas supply tank in the previous stage is extended according to the decrease in the flow rate of the gas filled in the filled tank. Insufficient pressure in the gas supply tank can be compensated by filling the gas from the preceding gas supply tank, and the filling time can be shortened.

According to a fourth aspect of the present invention, the switching timing changing control means controls the gas from the front stage gas supply tank to the rear stage gas on the basis of the pressure difference between the pressure of the front stage gas supply tank and the rear stage gas supply tank. It is characterized in that the switching timing for switching to the supply tank is changed.

Therefore, according to the fourth aspect, the switching timing for switching from the front gas supply tank to the rear gas supply tank based on the pressure difference between the pressure of the front gas supply tank and the pressure of the rear gas supply tank is set. Because of the change, the pressure shortage of the gas supply tank in the latter stage can be compensated by the gas filling from the gas supply tank in the former stage according to the pressure difference between the two tanks, and the filling time can be shortened.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram of a gas supply device according to the present invention. The gas supply device 1 is installed, for example, at a gas supply station that supplies compressed natural gas (CNG) obtained by compressing city gas to a predetermined pressure to a fuel tank (filled tank) 3 of an automobile 2. The compressed natural gas is an example, and the gas handled by the gas supply device 1 is not limited to this, and includes other gases that are compressed and used in a high pressure range from atmospheric pressure to about 200 atm.

The gas supply device 1 generally includes a pressure generating unit 4 for increasing the city gas to a predetermined pressure, a dispenser unit 5 for supplying the gas compressed by the pressure generating unit 4 to the fuel tank 3, and these pressures. The control unit 6 controls each device of the generation unit 4 and the dispenser unit 5.

The pressure generating unit 4 includes a branch line 11 which is branched from a medium pressure line before city gas is branched to a home.
The compressor 12 is disposed in the. The compressor 12 is, for example, a multi-stage type in which a plurality of cylinders for compressing gas are provided, and the gas compressed by the cylinder of the previous stage is pressurized to a higher pressure by the cylinder of the next stage to gradually increase the gas. Compress to.

Further, a check valve 14 for preventing the reverse flow of the gas generated by the compressor 12 is provided in the high pressure line 13 drawn out from the compressor 12.
A variable pressure gas accumulator 17 as a gas supply tank and a high pressure gas accumulator 18 are connected to the ends of the branch pipes 15 and 16 branched from the high pressure pipe 13.
The variable pressure gas accumulator 17 and the high pressure gas accumulator 18 are
Generally, it is also referred to as "gas storage device" in the literature.

The variable pressure gas accumulator 17 and the high pressure gas accumulator 18 store the high pressure gas compressed by the compressor 12, that is, the gas compressed to 250 kgf / cm ² in this embodiment. Further, the branch pipes 15 and 16 are provided with first and second opening / closing valves 19 and 20, which are electromagnetic valves, pressure transmitters 21 and 22, and manual opening / closing valves 23 and 24. .

The pressure transmitters 21 and 22 are respectively installed in the gas accumulator 1 through branch pipes 15 and 16.
A pressure sensor for detecting the pressures of 7 and 18 is provided, and a detection signal corresponding to the pressure of the gas accumulators 17 and 18 is output to the control device 6. In addition, the upstream side of the gas supply line 28 that communicates with the branch lines 15 and 16 is a third valve including a solenoid valve.
An on-off valve 26 is provided. This third on-off valve 26
Is closed when the gas compressed by the compressor 12 is supplied to the gas pressure accumulators 17 and 18, and prevents the gas from flowing out to the dispenser unit 5. The valve is opened when the tank 3 is filled.

The manual on-off valves 23 and 24 are normally in the open state, and for example, when the on-off valves 19 and 20 fail, or when the on-off valves 19 and 20 are inspected, the valve closing operation is performed. To be done. Therefore, in the process in which the gas compressed by the compressor 12 is supplied to the gas pressure accumulators 17 and 18, the first and second opening / closing valves 19 and 20 are opened and the third opening / closing valve 26 is closed. It When the pressure inside the gas pressure accumulators 17 and 18 reaches a predetermined pressure, the first and second on-off valves 19 and 20 are closed, and the pressure generating unit 4 is ready for a filling operation.

Since the amount of gas filling the fuel tank 3 from the gas pressure accumulators 17 and 18 varies depending on the remaining amount of the fuel tank 3, as will be described later, the variable pressure gas accumulator 17 at the preceding stage is used. When the fuel tank 3 reaches the target filling pressure by the gas supply of, the pressure of the fuel tank 3 is increased to the specified pressure of the first stage by the variable pressure gas accumulator 17 of the former stage, and then the high pressure gas accumulator 18 of the latter stage is There is a case where the pressure of the fuel tank 3 is increased to the target filling pressure by switching to the.

In the memory 27 of the control device 6, as will be described later, the switching timing change for changing the switching timing for switching from the variable pressure gas pressure accumulator 17 to the high pressure gas pressure accumulator 18 according to the pressure of the high pressure gas pressure accumulator 18 is changed. A control program as control means is stored.

The pressure generating unit 4 and the dispenser unit 5 are connected to each other via a gas supply pipe line 28. The gas supply pipe 28 extending into the dispenser unit 5 has an opening / closing valve 29 made of an electromagnetic valve.
A primary pressure transmitter 30 that detects the pressure of the gas supplied from the pressure generation unit 4, a flow meter 31 that measures the flow rate of the gas flowing through the gas supply pipe 28, and the pressure that is fed downstream. Control valve 3 for controlling the flow rate to a predetermined value
2, a secondary pressure transmitter 33 that detects the secondary pressure supplied to the downstream of the control valve 32, and an emergency disconnection coupler 34 that separates when pulled by a force greater than a predetermined value.

The on-off valve 29 functions as a main valve of the pressure generating unit 4, and opens or closes in response to a command from the control device 6. The primary pressure transmitter 30 and the secondary pressure transmitter 33 detect pressure changes from the start of gas filling of the fuel tank 3 to the end of gas filling.

As the flow meter 31, a Coriolis mass flow meter capable of accurately measuring the flow rate of the high pressure gas is adopted, and the flow rate measurement signal is transmitted to the control device 6. Therefore, the control device 6 integrates the flow rate measured by the flow meter 31, and controls the opening / closing of the opening / closing valve 29 and the valve opening degree of the control valve 32.

The valve opening of the control valve 32 is controlled by the controller 6 by a constant pressure increase control for filling the gas at a constant pressure increase or a constant flow rate control for filling the gas at a constant flow rate. Reference numeral 36 is an indicator, which is the filling amount and filling pressure (secondary pressure) of the gas filled in the fuel tank 3.
Is displayed.

Further, one end of a high pressure gas supply tube 37 capable of withstanding high pressure gas is connected to the emergency disconnecting coupler 34, and the other end of the high pressure gas supply tube 37 is connected to an inflow port a of a three-way valve 38. Further, a flexible supply hose 39 is connected to the filling port b of the three-way valve 38. A detachable coupler 40 is provided at the end of the supply hose 39.

The exhaust port c of the three-way valve 38 is connected to a low pressure pipe 41 for releasing residual gas in the detachable coupler 40 to the outside so that the detachable coupler 40 can be detached after the gas supply is completed. There is. The low-pressure pipe line 41 is connected to a gas recovery path that opens the atmosphere or recovers the residual gas in the detachable coupler 40.

The three-way valve 38 is constructed so that it can be switched by manual operation. Before and after gas filling, the filling port b and the exhaust port c are in communication with each other and the inflow port a is blocked. Further, at the time of gas filling, switching operation is performed so that the inflow port a and the filling port b communicate with each other and the exhaust port c is shut off.

The emergency disconnection coupler 34 is provided inside the emergency disconnection coupler 34 in case the automobile 2 is departed while the disconnection coupler 40 is still connected to the removal coupler 42 on the fuel tank 3 side. A check valve (not shown) provided closes to prevent gas leakage.

In the automobile 2 filled with high-pressure gas, a detachable coupler 42 to which the detachable coupler 40 is connected from the upstream side to a pipeline 44 connected to the fuel tank 3,
A manual opening / closing valve 45 that is opened by a manual operation when filling the gas and a check valve 46 that prevents the gas filled in the fuel tank 3 from flowing backward are provided.

Next, before explaining the processing executed by the control device 6, the gas filling work in the gas supply device 1 having the above-mentioned configuration will be explained. Fuel tank 3 of the car 2
When filling the gas with the gas, the worker first attaches the detachable coupler 40 of the dispenser unit 5 to the detachable coupler 42 of the automobile 2.
To be combined. Then, the operator opens the manual opening / closing valve 46 of the automobile 2 and performs a switching operation so that the inflow port a and the filling port b of the three-way valve 38 communicate with each other.

Next, when the start button (not shown) for starting the filling is turned on, the control device 6 causes the variable pressure gas accumulator 1 to operate.
The opening / closing valve 19 of No. 7 is opened, and the gas supply opening / closing valve 29 is opened. Thereby, the variable pressure gas accumulator 17
The high pressure gas stored in the fuel tank 3 is filled in the fuel tank 3 through the gas supply pipe line 28, the gas filling hose 37, the detachable couplers 40 and 42, and the pipe line 44.

When the pressure with which the fuel tank 3 is filled rises to the specified pressure in the first stage and the pressure in the variable pressure gas accumulator 17 decreases, the difference between the primary pressure and the secondary pressure becomes small. The on-off valve 19 of the variable pressure gas accumulator 17 is closed, and the on-off valve 20 of the high pressure gas accumulator 18 is opened to fill the gas.

When the fuel tank 3 becomes full, the open / close valve 20 of the high-pressure gas accumulator 18 is closed and
The gas supply opening / closing valve 29 is closed. The gas filling flow rate that has passed through the gas supply line 28 is measured by a flow meter 31,
A flow rate pulse corresponding to the gas filling flow rate is output to the control device 6.

As a result, the control device 6 calculates the amount of gas filled in the fuel tank 3 based on the supply pressure detected by the secondary pressure transmitter 33 and the number of flow rate pulses from the flow meter 31. Is displayed on the display 36. When the gas filling into the fuel tank 3 is completed, the worker closes the manual opening / closing valve 45 on the side of the automobile 2 and then connects the three-way valve 38 to the filling port b and the exhaust port c and shuts off the inflow port a. Switching operation is performed. That is, the three-way valve 38 allows the gas remaining in the detachable couplers 40 and 42 and the filling hose 39 to escape to the outside through the low pressure pipe 41 to reduce the pressure, and enables the detaching operation of the detachable coupler 40.

After that, the worker operates the dispenser unit 5
The detachable coupler 40 is separated from the detachable coupler 42 of the automobile 2. This completes a series of gas filling operations. Here, a process executed by the control device 6 of the gas supply device 1 having the above configuration will be described. Note that FIG. 2 is a main flowchart executed by the control device 6 during the gas filling work.

As described above, the worker is required to operate the gas supply line 2
The detachable coupler 40 provided at the tip of 8 is connected to the detachable coupler 42 of the fuel tank 3, and then the inflow port a and the filling port b of the three-way valve 38 are made to communicate with each other, and the manual on-off valve 46 is opened. To do. Then, the operator turns on the start button.

When the start button is turned on in step S1 (hereinafter "step" is omitted), the control device 6 proceeds to step S2 and determines whether the fuel tank 3 is full. That is, it is checked whether the pressure P detected by the secondary pressure transmitter 33 is equal to or higher than the filling target pressure (full tank pressure) Po, and in this embodiment, the pressure of the fuel tank 3 is set to 200 kgf / cm ² . If it has reached, it is judged as "full".

Therefore, in S2, the secondary pressure transmitter 3
The pressure detected by 3 is the target pressure Po (200 kgf / cm
² ), the fuel tank 3 is full, so
After shifting to S12, all valves are closed and the fuel tank 3
The gas filling control for is ended.

However, when the pressure P detected by the secondary pressure transmitter 33 in S2 is less than the target pressure Po, it is judged that the fuel tank 3 is not full and gas filling is possible, and the routine proceeds to S3. In S3, the opening / closing valve 19 of the variable pressure gas accumulator 17 is opened, and the gas supply opening / closing valve 29 of the dispenser unit 5 is opened. As a result, gas filling of the fuel tank 3 is started.

After that, the process proceeds to S4 and the variable pressure gas pressure accumulator 1
The gas filling control by 7 is performed. That is, in S4, the valve opening degree of the control valve 32 is controlled so as to fill the gas at the optimum flow rate according to the capacity of the fuel tank 3. In the next S5, it is determined again whether the fuel tank 3 is full. Therefore, when the pressure P detected by the secondary pressure transmitter 33 after the start of the gas filling control by the variable pressure gas accumulator 17 is the target pressure Po (P ≧ Po), the fuel tank 3 is full, The gas filling control is ended without executing the subsequent processing. That is, when the fuel tank 3 is full, S1
After shifting to 2, the on-off valve 19 of the variable pressure gas accumulator 17 is closed and the gas supply on-off valve 29 is closed. This completes the gas filling control for the fuel tank 3.

However, in S5, the secondary pressure transmitter 3
When the pressure P detected by 3 is less than the target pressure Po (P <Po), the fuel tank 3 is not yet full, so the process proceeds to S6. In S6, it is determined whether to continue the gas filling control by the variable pressure gas accumulator 17 or switch to the gas filling control from the high pressure gas accumulator 18.

That is, in S6, as will be described later, the flow rate Q supplied to the fuel tank 3 is the high pressure gas accumulator 18
The flow rate Q measured by the flow meter 31 is equal to or higher than the switching flow rate Qa, and if the flow rate Q measured by the flow meter 31 is equal to or higher than the switching flow rate Qa, the process returns to S3 and the variable pressure gas accumulator is returned. The gas filling control by 17 is continued.

However, in S6, the flow meter 31
When the flow rate Q measured by is less than the switching flow rate Qa, the gas filling control by the variable pressure gas accumulator 17 is switched to the gas filling control by the high pressure gas accumulator 18. In that case, the process proceeds from S6 to S7, and the open / close valve 20 of the high pressure gas pressure accumulator 18 is opened.

In the next S8, a predetermined time (in this embodiment,
1 second) is determined. Then, after a lapse of a predetermined time, it is determined that the pressure of the high-pressure gas accumulator 18 has started to be filled in the fuel tank 3 via the gas supply conduit 28, and the process proceeds to S9. Therefore, in the next S9, the opening / closing valve 21 of the variable pressure gas pressure accumulator 17 is closed at the time when the gas in the high pressure gas pressure accumulator 18 is started to be filled in the fuel tank 3. After that, gas filling control by the high-pressure gas accumulator 18 is performed (S10).

When the gas filling by the variable pressure gas pressure accumulator 17 is completed, when the gas supply from the variable pressure gas pressure accumulator 17 is stopped and then the gas supply from the high pressure gas pressure accumulator 18 is started, the pressure accumulation is started. Pressure fluctuations occur when switching between
As in the present embodiment, by stopping the gas supply by the variable pressure gas accumulator 17 after starting the gas supply by the high pressure gas accumulator 18, it is possible to suppress the pressure fluctuation at the time of switching the accumulator.

Then, in S11, it is determined whether or not the fuel tank 3 is full, and the fuel tank 3 is filled with gas until the pressure detected by the secondary pressure transmitter 33 reaches the filling target pressure Po. Control is performed. Further, in S11, when the pressure filled in the fuel tank 3 by the gas supply from the high pressure gas accumulator 16 reaches the filling target pressure Po in this way, it is determined that the fuel tank 3 is full.
Therefore, when the fuel tank 3 is full, the routine proceeds to S12, where the on-off valve 20 of the high pressure gas accumulator 18 is closed and the gas supply on-off valve 29 is closed. This completes the gas filling control for the fuel tank 3.

FIG. 3 is a flow chart of an interrupt process executed by the control device 6 every predetermined time. The control device 6 is
The switching flow rate Q which becomes a threshold value when switching the gas supply source from the variable pressure gas pressure accumulator 17 to the high pressure gas pressure accumulator 18 in S21.
a is calculated from the following equation.

Qa = k × (Pa−Po) (1) That is, the pressure Pa of the high pressure gas accumulator 18 in the subsequent stage is read from the pressure transmitter 22 and the target filling pressure (full tank pressure) is obtained.
The difference k between Po and the pressure Pa of the high pressure gas accumulator 18 is multiplied by a coefficient k to calculate the switching flow rate Qa. By performing this calculation, the switching flow rate Qa at that time is set.

Then, in S22, the flow rate Q currently filled in the fuel tank 3 and the switching flow rate Q obtained in S21.
It is compared with a and it is determined whether the control valve 32 is fully opened. In S22, the current flow rate Q is smaller than the switching flow rate Qa, and the valve opening degree of the control valve 32 is 10
When it is 0% or more, the process proceeds to S23 and the gas supply source is switched from the variable pressure gas pressure accumulator 17 to the high pressure gas pressure accumulator 18.

However, in S22, when the current flow rate Q is larger than the switching flow rate Qa or the valve opening degree of the control valve 32 is less than 100%, the process proceeds to S24 and the gas from the variable pressure gas pressure accumulator 17 is transferred. Continue filling. This completes the interrupt processing. In this way, the switching flow rate Qa is determined by the difference (Pa-Po) between the pressure Pa of the high-pressure gas accumulator 18 and the filling target pressure Po, so the high-pressure gas accumulator 1
When the pressure Pa of 8 is the normal filling pressure (250 kgf / cm ² ), the gas supply source is switched from the variable pressure gas pressure accumulator 17 to the high pressure gas pressure accumulator 18 at the same switching timing as in the conventional case.

However, when the pressure Pa of the high pressure gas accumulator 18 is lower than the normal filling pressure (250 kgf / cm ² ), the pressure Pa of the high pressure gas accumulator 18 and the filling target pressure P
Since the difference (Pa-Po) from o becomes small, the switching flow rate Qa as a threshold for determining the switching timing is set to a small value.

Therefore, the pressure Pa of the high pressure gas accumulator 18 is
Is small, the switching timing is delayed by a time corresponding to the difference (Pa-Po) between the pressure Pa of the high-pressure gas accumulator 18 and the target filling pressure Po. Therefore, the variable pressure gas accumulator 1
The gas filling control by 7 is extended by the delay of the switching timing.

As a result, the pressure Pa of the high pressure gas accumulator 18 is increased by continuously filling the gas or filling a large vehicle.
Even when the pressure is low, the pressure Pa of the high pressure gas accumulator 18 in the subsequent stage is
Since the switching timing for switching from the variable pressure gas pressure accumulator 17 in the preceding stage to the high pressure gas pressure accumulator 18 can be changed based on the above, the gas filling time by the variable pressure gas pressure accumulator 17 is changed according to the pressure Pa of the high pressure gas pressure accumulator 18. Can be extended to compensate for the lack of pressure in the high-pressure gas accumulator 18, and as a result, the filling time (the time from the start of filling until the tank is full) can be shortened.

FIG. 4 is a graph of experimental results showing the relationship between the filling time and the difference in the switching timing for switching from the variable pressure gas pressure accumulator 17 to the high pressure gas pressure accumulator 18 when the pressure of the high pressure gas pressure accumulator 18 is low. . This graph is a result of comparison between the conventional switching timing Ta and the switching timing Tb of the present invention. From this graph, comparing the filling time Tc according to the switching timing Tb of the present invention in which the switching timing is changed according to the pressure Pa of the high pressure gas accumulator 18 as described above and the filling time Td according to the conventional switching timing Ta, Tc < It becomes Td, and it is understood that the filling time is shortened by delaying the switching timing and extending the filling control by the variable pressure gas pressure accumulator 17.

FIG. 5 shows a fuel tank for a large vehicle (capacity 50
It is the result of measuring the filling time due to the difference in pressure between the variable pressure gas pressure accumulator 17 and the high pressure gas pressure accumulator 18 when the gas is charged to 0 liters). Further, in FIG. 5, the pressure of the variable pressure gas accumulator 17 and the high pressure gas accumulator 18 is set to 21 MPa,
The conventional switching timing Ta and the switching timing Tb of the present invention are compared with each other by taking Cases 1 to 23 at 22 MPa and 24 MPa as an example.

In case 1, the variable pressure gas accumulator 17
Since the pressure of the high pressure gas accumulator 18 is 24 MPa, which is a sufficient pressure, the switching flow rate is set to 12 kg / min in both the conventional case and the present invention. Therefore, in both the conventional case and the present invention, it takes 300 seconds to raise the pressure of the fuel tank 3 to 20 MPa, and the normal filling is performed.

In case 2, variable pressure gas accumulator 17
Since the pressure of the high-pressure gas accumulator 18 is 22 MPa, which is rather low, the switching flow rate is 12 kg / min in the conventional case and the present invention is 7 kg / min.
Is set to In this case, the switching timing of the present invention is delayed as compared with the conventional switching timing, and as a result, it takes 500 seconds to raise the pressure of the fuel tank 3 to 20 MPa, whereas 400 seconds in the present invention. Therefore, the filling time can be shortened by 100 seconds.

In case 3, the variable pressure gas accumulator 17 is used.
Since the pressure of the high pressure gas accumulator 18 is as low as 21 MPa, the switching flow rate is conventionally 12 kg / min, and the present invention is set to 5 kg / min. In this case, the switching timing of the present invention is delayed as compared with the conventional switching timing. As a result, it takes 500 seconds for the present invention to increase the pressure of the fuel tank 3 to 20 MPa, whereas in the conventional case,
Since it takes 500 seconds to raise the pressure of 19 to 19 MPa, the filling pressure becomes insufficient at the conventional switching timing.

As described above, it can be seen from the experimental results that the filling time into the fuel tank 3 can be shortened by changing the switching timing according to the pressure of the high pressure gas accumulator 18. Further, it can be seen that when the pressure of the high pressure gas accumulator 18 is low, the filling pressure can be made higher even if the filling time is the same.

FIG. 6 is a flow chart of a gas accumulator switching timing interrupt process as a modification of the present invention. The interrupt process is repeatedly executed every 10 msec, and the gas accumulator switching timing changes every moment. The control device 6 obtains the switching pressure P, which is a threshold value when switching the gas supply source from the variable pressure gas pressure accumulator 17 to the high pressure gas pressure accumulator 18 in S31, from the following equation.

P = Pb−k × (Pa−Pb) (2) That is, the pressure Pb of the variable pressure gas pressure accumulator 17 in the front stage is read from the pressure transmitter 21, and the high pressure gas pressure accumulator 18 in the rear stage is read.
Pressure Pa of the high pressure gas pressure accumulator 18 and pressure Pb of the variable pressure gas pressure accumulator 17 are read from the pressure transmitter 22.
The value obtained by multiplying the pressure difference between
Is subtracted from the pressure Pb. By performing this calculation,
The switching pressure P corresponding to the pressures of the variable pressure gas pressure accumulator 17 and the high pressure gas pressure accumulator 18 is obtained and set.

Then, in S32, the secondary pressure transmitter 33
The pressure Pc (pressure in the fuel tank 3) detected by the above is read, the secondary pressure value and the switching pressure P calculated in S31.
Compare with At S32, the fuel tank 3 is filled with the gas of the variable pressure gas pressure accumulator 17 and the pressure of the variable pressure gas pressure accumulator 17 is decreased to decrease the current secondary pressure transmitter 33.
The secondary pressure detected by is smaller than the switching pressure P (P
When <Pc), the process proceeds to S33 and the gas supply source is switched from the variable pressure gas pressure accumulator 17 to the high pressure gas pressure accumulator 18.

However, in S32, when the secondary pressure detected by the current secondary pressure transmitter 33 is larger than the switching pressure P (P> Pc), the process proceeds to S34 and the variable pressure gas pressure accumulator 17 is operated. Continue gas filling. This completes the interrupt processing of the gas pressure accumulator switching timing.

When the interruption processing of the gas accumulator switching timing is executed, the coefficient k is assumed to be 1.0, the initial high pressure gas accumulator pressure Pa and the variable pressure gas accumulator pressure Pb are 24.
If MPa, the switching pressure is P = 24 from the above equation (2).
MPa. Further, when the high pressure gas accumulator pressure Pa decreases when the fuel tank 3 is started to be filled with gas, the switching pressure P also decreases according to the above formula (2). Then, for example, when the variable pressure gas pressure accumulator pressure Pb becomes 20 MPa, the switching pressure becomes P = 20− (24−20) = 16 MPa.

However, when the initial values of the high pressure gas pressure accumulator pressure Pa and the variable pressure gas pressure accumulator pressure Pb are 22 MPa,
When the variable pressure gas accumulator pressure Pb becomes 20 MPa, the switching pressure becomes P = 20− (22−20) = 18 MPa.
As the switching pressure P increases, the switching timing for switching from the variable pressure gas pressure accumulator 17 to the high pressure gas pressure accumulator 18 becomes slower, so that the same effect as in the case of the embodiment of FIG. 3 described above can be obtained.

In the above embodiment, the case where compressed natural gas (CNG) obtained by compressing city gas is supplied as an example. However, the present invention is not limited to this. For example, gas such as butane and propane may be supplied. Of course, it can be applied. Also,
In the above embodiment, the case where the fuel tank 3 of the automobile 2 is filled with the compressed gas has been described as an example, but the present invention is not limited to this, and can be applied to a device that supplies the compressed gas to another container, Alternatively, it is needless to say that the present invention can also be applied to an apparatus having a configuration in which a compressed gas is simply installed in the middle of a pipeline for feeding it to another place.

Further, in the above-mentioned embodiment, the city gas or the like is compressed from the medium pressure pipeline 10 before it is branched to the home. However, the present invention is not limited to this, and it is branched from the medium pressure pipeline 10, for example. The gas may be taken out from the household pipeline.

[0072]

As described above, according to the first aspect, the switching timing for switching from the gas supply tank at the front stage to the gas supply tank at the rear stage can be changed based on the pressure of the gas supply tank at the rear stage. When the pressure of the gas supply tank in the latter stage is lower than the specified pressure, the gas filling time of the tank to be filled by the gas supply tank in the former stage can be extended according to the pressure. Therefore, the pressure shortage in the gas supply tank in the latter stage can be compensated by the gas filling from the gas supply tank in the former stage, and the filling time can be shortened.

Further, according to the second aspect, when the difference between the pressure detected by the pressure detecting means and the target filling pressure is less than or equal to a predetermined value, the switching to the gas supply tank in the subsequent stage is delayed by a time corresponding to the pressure difference. Therefore, when the pressure of the gas supply tank in the subsequent stage exceeds the allowable range and is low, the switching to the gas supply tank in the subsequent stage can be delayed by the time required.
The filling time can be shortened.

Further, according to the third aspect, when the flow rate from the gas supply tank in the front stage becomes equal to or lower than the switching flow rate according to the pressure difference, the gas supply tank in the rear stage is switched to, so that the pressure in the gas supply tank in the rear stage is If the flow rate cannot be secured because it is lower than the specified pressure, the gas filling time to the filled tank by the gas supply tank in the previous stage is extended according to the decrease in the flow rate of the gas filled in the filled tank. Insufficient pressure in the gas supply tank can be compensated by filling the gas from the preceding gas supply tank, and the filling time can be shortened.

Further, according to the fourth aspect, the switching timing for switching from the gas supply tank at the front stage to the gas supply tank at the rear stage is set based on the pressure difference between the pressure of the gas supply tank at the front stage and the pressure of the gas supply tank at the rear stage. Because of the change, the pressure shortage of the gas supply tank in the latter stage can be compensated by the gas filling from the gas supply tank in the former stage according to the pressure difference between the two tanks, and the filling time can be shortened.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an embodiment of a gas supply device according to the present invention.

FIG. 2 is a main flowchart for explaining a process executed by a control device during a gas filling operation.

FIG. 3 is a flowchart of an interrupt process executed by the control device at predetermined time intervals.

FIG. 4 is a graph of experimental results showing the relationship between the switching timing difference and the filling time when the pressure of the high-pressure gas accumulator is low.

FIG. 5 is a diagram showing a result of measuring a filling time due to a difference in pressure of a gas pressure accumulator when a gas is filled in a fuel tank (capacity: 500 liters) for a large vehicle.

FIG. 6 is a flowchart of interrupt processing for explaining a modified example of the present invention.

[Explanation of symbols]

 1 Gas Supply Device 3 Fuel Tank 4 Pressure Generation Unit 5 Dispenser Unit 6 Control Device 12 Compressor 17 Variable Pressure Gas Accumulator 18 High Pressure Gas Accumulator 19,20 Open / close Valve 21,22 Pressure Transmitter 28 Gas Supply Pipeline 29 Gas Supply Open / Close Valve 30 Primary pressure transmitter 31 Flow meter 32 Control valve 33 Secondary pressure transmitter

Claims (4)

[Claims] 1. A method for filling a filled tank from a gas supply tank in a first stage among a plurality of gas supply tanks for storing compressed gas and then filling a filled tank from a gas supply tank in a second stage In a gas supply device for switching the communication between the plurality of gas supply tanks and the tank to be filled to increase the pressure of the tank to be filled to a target filling pressure stepwise, from the gas supply tank in the first stage to the gas supply tank in the second stage. A gas supply device characterized in that a switching timing change control means for changing the switching timing for switching is provided. 2. When the difference between the pressure of the rear gas supply tank and the target filling pressure is less than or equal to a predetermined value, the switching timing change control means switches to the rear gas supply tank for a time corresponding to the pressure difference. Delaying, characterized in that
Gas supply device. 3. The switching timing change control means obtains a switching flow rate from the difference between the pressure of the gas supply tank in the subsequent stage and the target filling pressure, and when the flow rate from the gas supply tank in the previous stage is equal to or less than the switching flow rate, The gas supply apparatus according to claim 1, wherein the gas supply tank is switched to a latter stage. 4. The switching timing for switching from the gas supply tank in the front stage to the gas supply tank in the rear stage based on the pressure difference between the pressure in the gas supply tank in the front stage and the pressure in the gas supply tank in the rear stage. The gas supply device according to claim 1, wherein