JP2010174912A - Method and device for measuring residual pressure in gas container - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To inexpensively execute accurate calculation of residual gas pressure in a gas container without installation of an electric pressure sensor to a container valve, or while maintaining a small size of the container valve and reducing the necessary number of pressure sensors in the whole system. <P>SOLUTION: A storage gas pressure in the gas container (2) in connection to a gas supply passage (6) is stored as an initial cylinder pressure (P<SB>0</SB>). The ratio of pressure reduction (Δp) of secondary pressure (p) of a pressure reducing valve (4) to pressure reduction (ΔP) of primary pressure (P) thereof is stored as pressure reducing characteristic coefficient (α) of the pressure reducing valve (4). A standard initial secondary pressure (p<SB>0S</SB>) set relative to the initial cylinder pressure (P<SB>0</SB>) is stored. The secondary pressure (p) fluctuated by consumption of gas is measured by a secondary pressure measuring means (25), and the residual gas pressure in the gas container (2) having the primary pressure (P) is calculated according to the relational expression of P=P<SB>0</SB>-(p<SB>0S</SB>-p)÷α from this secondary pressure (p), the initial cylinder pressure (P<SB>0</SB>), the standard initial secondary pressure (p<SB>0S</SB>), and the pressure reducing characteristic coefficient (α). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method and an apparatus for measuring a residual pressure in a gas container provided with a container valve having a pressure reducing valve. More specifically, the present invention can accurately calculate the residual gas pressure in the gas container, A method for measuring the residual pressure in a gas container, which can be implemented at low cost by reducing the number of pressure sensors in the entire system, while maintaining a small container valve without the need to install a typical pressure sensor. The present invention relates to a residual pressure measuring device.

  For example, in-vehicle fuel cell systems using hydrogen gas as fuel, there is one that removably connects a hydrogen gas container to a fuel cell that is a gas consuming device. In this case, in order to increase the size and capacity of the hydrogen gas container, it is desired to increase the pressure, for example, 35 MPa, and there is a hydrogen gas container having a pressure reducing valve (see, for example, Patent Document 1). .

  When the stored gas in the gas container is reduced to a predetermined residual gas pressure or lower due to gas consumption, it cannot be used in the gas consuming device, and is therefore replaced with a new gas container filled with fresh gas. For this reason, the above gas container needs to measure the residual gas pressure in the gas container in order to confirm the replacement time, and the measured value is at a position where it can be easily confirmed, such as the driver's seat of a fuel cell vehicle. Is displayed.

  Conventionally, as a residual pressure measurement system in the above gas container, an electrical pressure sensor is attached to a container valve or the like, an output from the pressure sensor is input to an arithmetic device such as a controller, and the calculation result is output to a fuel gauge (For example, refer to Patent Document 2, hereinafter referred to as Prior Art 1).

This prior art 1 has an advantage that the residual gas pressure in the gas container can be measured by the pressure sensor, and the consumption state of the stored gas and the replacement timing of the gas container can be accurately grasped. However, this prior art 1 has the following problems because the pressure sensor is mounted on a container valve or the like.
(1) Since a connector for electrically connecting the pressure sensor and the arithmetic unit and the display device is required, the connector must be attached and detached when replacing the gas container, and the replacement work is complicated.
(2) Since a pressure sensor and a connector connected to the pressure sensor are attached to the container valve, the container valve becomes large and it is not easy to transport the gas container.
(3) Since this connector is attached / detached when the gas container is replaced, there is a possibility that the connector will be damaged when attaching / detaching the gas container, and when the gas container is transported, there is a possibility that the connector or the pressure sensor will be damaged. is there.
(4) The above pressure sensor must be attached not only to gas containers connected to gas consuming equipment, but also to all gas containers including empty gas containers and gas containers in stock. Since a large number of pressure sensors are required, it cannot be implemented inexpensively.

  In order to solve the above problems, for example, the gas consumption is calculated by measuring the amount of gas consumed by the gas consuming device and the gas flow rate through the gas supply path, and this is subtracted from the amount of gas stored in the gas container. Thus, a method of calculating the residual gas amount has been proposed (see, for example, Patent Document 3, hereinafter referred to as Conventional Technology 2).

  However, for example, in an in-vehicle fuel cell system using hydrogen gas as a fuel, a fuel cell system that is a gas consuming device, such as a system that purges moisture with hydrogen gas or a system that collects and circulates unreacted hydrogen gas Therefore, in this conventional technique 2, there are many items to be set for each gas consuming device, these setting operations are complicated, and it is not easy to calculate an accurate residual gas amount from the gas consumption amount. . In addition, when the gas is leaked from the gas container when used for a long period of time, the conventional technique 2 has a problem that the remaining gas in the gas container cannot be measured accurately.

JP 2006-048881 A JP-A-2005-240854 Japanese Patent Laid-Open No. 07-197858

  The technical problem of the present invention is to eliminate the above-mentioned problems, accurately calculate the residual gas pressure in the gas container, and further eliminate the need to attach an electrical pressure sensor to the container valve, and reduce the container valve to a smaller size. Another object of the present invention is to provide a residual pressure measuring method and a residual pressure measuring device in a gas container that can be maintained at a low cost by reducing the required number of pressure sensors in the entire system.

  Generally, the pressure reducing valve includes a type in which the secondary pressure increases when the primary pressure decreases and a type in which the secondary pressure decreases. However, in any type of pressure reducing valve, the primary pressure corresponding to a specific secondary pressure varies due to processing errors and assembly errors of each component, and is not constant. However, the present inventors have measured and observed the pressure reducing characteristics of various pressure reducing valves, and the fluctuation range of the secondary pressure with respect to the reduction range of the primary pressure is substantially constant according to the structure and type of the pressure reducing valve. The present invention was completed focusing on this fact.

In order to solve the above problems, the present invention is configured as follows, for example, based on FIGS. 1 to 5 showing an embodiment of the present invention.
That is, the present invention 1 relates to a method for measuring a residual pressure in a gas container. A gas valve (3) having a pressure reducing valve (4) is attached to the gas container (2), and a gas outlet ( 5) is a residual pressure measuring method for measuring the residual gas pressure in the gas container (2), which is detachably connected to the gas supply path (6) of the gas consuming device (1), and includes the above gas The stored gas pressure in the gas container (2) at the time of connection to the supply path (6) is stored as the initial container pressure (P ₀ ), and the pressure of the primary pressure (P) of the pressure reducing valve (4) The ratio of the pressure drop (Δp) of the secondary pressure (p) to the drop (ΔP) is stored as the pressure reduction characteristic coefficient (α) of the pressure reducing valve (4), and the ratio to the initial container pressure (P ₀ ) is stored. The set standard initial secondary pressure (p _0S ) is stored, the secondary pressure (p) fluctuated due to gas consumption is measured, the measured secondary pressure (p), and the initial pressure vessel pressure (P ₀₎ and standard Year secondary pressure because (p _0S) and decompression characteristic coefficient (alpha), the following equation (i)
P = P ₀ − (p _0S −p) ÷ α (i)
Thus, the residual gas pressure in the gas container (2), which is the primary pressure (P), is calculated.

Further, the present invention 2 relates to a device for measuring the residual pressure in a gas container. The gas container (2) is provided with a container valve (3) having a pressure reducing valve (4), and a gas outlet ( 5) is a residual pressure measuring device, which is detachably connected to the gas supply path (6) of the gas consuming device (1) and measures the residual gas pressure in the gas container (2). Secondary pressure measuring means (25) attached to the supply passage (6) for measuring the secondary pressure (p) reduced by the pressure reducing valve (4), and output from the secondary pressure measuring means (25) Calculation means (29) for calculating the residual gas pressure in the gas container (2) based on the above, and residual pressure display means (30) for displaying the calculation result by the calculation means (29). The means (29) includes a calculation unit (31) and a storage unit (32), and the storage unit (32) is provided in the gas container (2) when connected to the gas supply path (6). initial vessel pressure is stored gas pressure (P ₀₎ , Two for the initial container pressure (P ₀₎ said pressure reducing valve set for a (4) standard initial secondary pressure by (p _0S), pressure drop in the primary pressure (P) ([Delta] P) The pressure reduction characteristic coefficient (α), which is the ratio of the pressure drop (Δp) of the secondary pressure (p), is stored, and the calculation unit (31) calculates the second pressure measured by the secondary pressure measuring means (25). From the secondary pressure (p), the initial vessel pressure (P ₀ ), the standard initial secondary pressure (p _0S ) and the pressure reduction characteristic coefficient (α), the following equation (i)
P = P ₀ − (p _0S −p) ÷ α (i)
Thus, the residual gas pressure in the gas container (2), which is the primary pressure (P), is calculated.

The initial container pressure (P ₀ ) is a set gas pressure when the gas container is fully filled with fresh gas, and is constant according to the gas container. In addition, the pressure reducing valve provided in the container valve attached to the gas container has a standard initial secondary pressure (p _0S ) with respect to the initial container pressure (P ₀ ) as the pressure reducing characteristic. For this pressure reducing valve, the pressure reducing characteristic coefficient (α) which is the ratio of the pressure drop (Δp) of the secondary pressure (p) to the pressure drop (ΔP) of the primary pressure (P) (ie, α = Δp ÷ ΔP Is also found to be substantially constant. As a result, the initial vessel pressure (P ₀ ), the standard initial secondary pressure (p _0S ), and the pressure reduction characteristic coefficient (α) are treated as constants, and the secondary pressure (p) measured at an arbitrary time point is expressed as these. By substituting it into the above equation (i) together with the constant, the primary pressure (P) at that time is calculated.

In this case, the pressure reducing characteristic of the pressure reducing valve is the ratio of the standard initial secondary pressure (p _0S ) to the initial vessel pressure (P ₀ ) instead of the standard initial secondary pressure (p _0S ). _May be set as the standard pressure reduction ratio (r _S ) of this pressure reducing valve (ie, r _S = p _0S ÷ P ₀ ). In this case, the standard pressure reduction ratio (r _S ) is stored, and the product of the standard pressure reduction ratio (r _S ) and the initial vessel pressure (P ₀ ) is the standard of the above formula (i). The residual gas pressure in the gas container can be calculated by substituting the initial initial secondary pressure (p _0S ).

Note that the ratio of the actual secondary pressure (p) to the initial vessel pressure (P ₀ ) of the pressure reducing valve varies due to the processing error, the assembly error, etc., and therefore the standard initial secondary pressure (p _The primary pressure calculated using _0S ) or the standard pressure reduction ratio (r _S ) may cause an error. However, even if the error occurs, the magnitude is constant regardless of the fluctuation of the primary pressure. Therefore, the error generated in the calculated primary pressure can be sufficiently reduced by increasing the machining accuracy and sufficiently reducing the variation.

On the other hand, instead of calculating the residual gas pressure by the above equation (i) using the initial secondary pressure (p _0S ), when connecting the gas container and the gas supply path, The secondary pressure (p) taken out from the pressure reducing valve is stored as the initial secondary pressure (p ₀ ), and the measured secondary pressure (p), the initial container pressure (P ₀ ), and the initial secondary pressure are stored. From the pressure (p ₀ ) and the pressure reduction characteristic coefficient (α), the following equation (ii)
P = P ₀ − (p ₀ −p) ÷ α (ii)
When the residual gas pressure in the gas container, which is the primary pressure (P), is calculated by the above, the error generated in the calculated primary pressure is greatly reduced even if there is a processing error or an assembly error. And the primary pressure can be calculated more accurately.

Even when this equation (ii) is used, instead of the initial secondary pressure (p ₀ ), the ratio of the initial secondary pressure (p ₀ ) to the initial container pressure (P ₀ ) stored as vacuum ratio of the pressure reducing valve (r) (i.e., _{r = p 0 ÷ P 0.} ), the reduced pressure ratio (r) of the initial container pressure (P ₀₎ product of the above (ii The residual gas pressure in the gas container can be calculated by substituting into the initial secondary pressure (p ₀ ) in the equation ( ₁ ).

  The pressure reducing valve may be of a type in which the secondary pressure increases when the primary pressure decreases, i.e., the pressure reducing characteristic coefficient is smaller than 0, or the secondary pressure decreases when the primary pressure decreases. In other words, the pressure reducing valve may have a pressure reducing characteristic coefficient larger than zero. However, in a pressure reducing valve having a pressure reducing characteristic coefficient smaller than 0, when the primary pressure becomes a low pressure near the use limit pressure, the secondary pressure is reversed from rising to falling. Therefore, after the secondary pressure is reversed, the above equations (i) and (ii) cannot be used, and when the stored gas in the gas container is consumed to a lower pressure, for example, In some cases, it is necessary to determine the replacement timing of the gas container based on the reduced pressure value after the next pressure has started to decrease.

  On the other hand, when a pressure reducing valve having a pressure reducing characteristic coefficient larger than 0 is used, the secondary pressure always corresponds to a specific primary pressure even when the primary pressure becomes low. The residual gas pressure in the gas container, which is the primary pressure (P), can be calculated from the secondary pressure, which is preferable.

Since the initial container pressure (P ₀ ) is set by the gas container, it can be stored in advance in the storage unit. However, when the gas container is provided with a pressure gauge, the calculation means is provided with an input means, and the initial container pressure (P ₀ ) read from the pressure gauge by the input means is stored in the storage unit. You may comprise so that it may input.
Further, the input means stores the pressure reduction characteristic coefficient (α), the standard initial secondary pressure (p _0S ), the standard pressure reduction ratio (r _S ), etc. according to the type of the pressure reducing valve. It is also possible to input to.

  Since the present invention is configured and operates as described above, the following effects can be obtained.

(1) Since the initial vessel pressure (P ₀ ), standard initial secondary pressure (p _0S ), standard pressure reduction ratio (r _S ), and pressure reduction characteristic coefficient (α) are all treated as constants, The residual gas pressure in the gas container can be calculated simply by measuring the next pressure (p). For this reason, the secondary pressure measuring means such as an electric pressure sensor may be attached to the gas consuming device side such as a vehicle equipped with a fuel cell system, and does not need to be attached to the container valve or the gas container side.

(2) Since there is no need to attach secondary pressure measuring means to the container valve or gas container side, it is not necessary to attach or detach the electrical connector of the secondary pressure measuring means when replacing the gas container, thus simplifying the replacement work. can do.
(3) Since the secondary pressure measuring means and the connector connected thereto are not attached to the container valve, the container valve can be kept small and the gas container can be easily transported.
(4) Since it is not necessary to attach or detach the electrical connector of the secondary pressure measuring means when replacing the gas container, the risk of damage to the connector due to this attachment and detachment can be reduced. Further, since the secondary pressure measuring means and the connector are not attached to the gas container or the container valve, there is no possibility of damaging them during transportation.
(5) The above secondary pressure measuring means only needs to be attached to the gas consuming device side, and it is not necessary to attach it to all gas containers. The required number can be reduced, and it can be implemented at low cost.

1 is a schematic circuit diagram of an in-vehicle fuel cell system including a gas container residual pressure measuring device according to a first embodiment of the present invention. It is a comparison table | surface of the primary pressure and secondary pressure which show the pressure reduction characteristic of the pressure reducing valve with which a container valve of 1st Embodiment is provided. It is a contrast graph which shows the pressure reduction characteristic of the pressure-reduction valve of 1st Embodiment. It is a comparison table of the primary pressure and the secondary pressure showing the pressure reduction characteristics of the pressure reducing valve provided in the container valve of the second embodiment. It is a contrast graph which shows the pressure-reduction characteristic of this type pressure reducing valve of 2nd Embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 to 3 show a first embodiment of the present invention. FIG. 1 is a schematic circuit diagram of an in-vehicle fuel cell system equipped with a gas container residual pressure measuring device, and FIG. 2 is attached to the gas container. A comparison table of primary pressure and secondary pressure showing the pressure reduction characteristics of the pressure reducing valve provided in the container valve, and FIG. 3 is a comparison graph showing the pressure reduction characteristics.

  As shown in FIG. 1, an in-vehicle fuel cell system (1), which is a gas consuming device, includes a plurality of gas containers (2 ...) filled with high-pressure hydrogen gas, and container valves attached to the gas containers (2). (3) and a gas supply path (6) having one end connected to a gas outlet (5) of a pressure reducing valve (4) provided in the container valve (3), and an intermediate portion of the gas supply path (6). A solenoid valve manifold (7) and a fuel cell (8) connected to the other end of the gas supply path (6).

The container valve (3) has a container connection port (10) and the gas outlet (5) formed on the outer surface of the housing (9), and the container connection port (10) and the gas outlet (5). A gas extraction path (11) is formed between the two. The gas extraction passage (11) is provided with an overflow prevention valve (12), a container base valve (13), and the pressure reducing valve (4). A pressure gauge (14) is provided in the middle of the gas outlet (11) between the container main valve (13) and the pressure reducing valve (4), and the gas filling provided on the outer surface of the housing (9). A filling passage (17) having a check valve (16) is formed between the opening (15). The housing (9) is provided with a container safety valve (18) communicating with the internal space of the gas container (2), and a gas extraction path (downstream of the pressure reducing valve (4) ( 11) is connected to a gas escape path (20) equipped with a secondary safety valve (19).
The gas outlet (5) is detachably connected to the gas supply path (6) by, for example, a quick joint (21).

The solenoid valve manifold (7) is provided with the gas supply path (6) in a state of passing through the interior, and a check valve (22) and a solenoid valve (23 are provided in the gas supply path (6). ) And a secondary pressure reducing valve (24) are provided in order from the upstream side. In addition, each gas supply path (6) connected to each gas container (2) is merged on the downstream side of the electromagnetic valve (23) in the electromagnetic valve manifold (7).
A first pressure sensor (25) is attached as a secondary pressure measuring means to the gas supply path (6) on the upstream side of the electromagnetic valve (23). Further, a second pressure sensor (26) and a safety valve (27) are attached to the gas supply path (6) joined to one downstream side of the secondary pressure reducing valve (24).

  A residual pressure measuring device (28) for measuring the residual gas pressure in the gas container (2) is attached to the vehicle side on which the fuel cell (8) is mounted. The residual pressure measuring device (28) includes the first pressure sensor (25), an arithmetic device (29) electrically connected to the first pressure sensor (25), and the arithmetic device (29). A residual pressure display device (30) for displaying the output of

The first pressure sensor (25) measures the secondary pressure (p) reduced by the pressure reducing valve (4), and outputs the measurement result to the arithmetic unit (29). The calculation device (29) includes a calculation unit (31) and a storage unit (32). In this storage unit (32), the stored gas pressure in the gas container (2) when connected to the gas supply path (6), that is, the set filling of the gas container (2) filled up The pressure reduction characteristic coefficient which is the ratio of the pressure drop (Δp) of the secondary pressure (p) to the pressure drop (ΔP) of the primary pressure (P) of the pressure reducing valve (4) and the initial container pressure (P ₀ ) (α) is stored.

The first pressure sensor (25) is connected to the pressure reducing valve (4) when the gas container (2) is mounted and the gas outlet (5) is connected to the gas supply path (6). The reduced initial secondary pressure (p ₀ ) is measured and output to the arithmetic unit (29). The storage unit (32) also stores the initial secondary pressure (p ₀ ).

The calculation unit (31) includes the measurement result of the secondary pressure (p) sent from the first pressure sensor (25), the initial container pressure (P ₀ ), and the initial secondary pressure (p ₀ ) and the decompression characteristic coefficient (α), the following equation (ii)
P = P ₀ − (p ₀ −p) ÷ α (ii)
Thus, the residual gas pressure in the gas container (2), which is the primary pressure (P), is calculated. The calculation result is output to the residual pressure display device (30) and displayed on the residual pressure display device (30).

  The remaining amount display device (30) may directly display the residual gas pressure in the gas container (2), but instead of this, for example, the full tank state of the gas container (2) is set to 1. The state where the residual pressure is the use limit pressure may be set to 0, and the interval between them may be displayed as a bar graph. Alternatively, when the residual pressure reaches the use limit pressure, the replacement time of the gas container (2) approaches. You may display so that it may warn.

Next, the operation of the on-vehicle fuel cell system and the residual pressure measuring device will be described.
First, a gas container (2) filled with hydrogen gas is mounted on the above-described on-vehicle fuel cell system (1). The gas container (2) is filled with hydrogen gas, for example, at a set filling pressure of 35 MPa, and the storage unit (32) stores this 35 MPa in advance as a constant initial container pressure (P ₀ ). is there.

  When the gas container (2) is mounted, the gas outlet (5) of the pressure reducing valve (4) is connected to the gas supply path (6). In this first embodiment, the pressure reducing valve (4) is of a type in which the secondary pressure decreases when the primary pressure decreases. The specific pressure reducing characteristics of the pressure reducing valve (4) are, for example, the relationship between the primary pressure and the secondary pressure shown in the comparison table of FIG. When this decompression characteristic is graphed, it is a straight line inclined upward as shown in FIG.

  According to the comparison table shown in FIG. 2, for example, when the primary pressure (P) is reduced from 35 MPa to 5 MPa, the secondary pressure (p) is reduced from 0.897 MPa to 0.075 MPa. Therefore, the ratio of the pressure drop (Δp) of the secondary pressure (p) to the pressure drop (ΔP) of the primary pressure (P), that is, the pressure reducing characteristic coefficient (α) of the pressure reducing valve (4) is 0.075 ÷ 5 = 0.015. The storage unit (32) previously stores 0.015 as a constant decompression characteristic coefficient (α).

In this embodiment, in order to calculate the pressure reduction characteristic coefficient (α), the ratio of the pressure drop of the secondary pressure (p) when the primary pressure (P) is reduced by 5 MPa from the initial vessel pressure (P ₀ ) is calculated. Calculated. However, in the present invention, the ratio may be calculated in other ranges, for example, the ratio of the pressure drop of the secondary pressure (p) when the primary pressure (P) is reduced by 30 MPa from the initial vessel pressure (P ₀ ).

Next, the container main valve (13) of the container valve (2) is opened, and the stored gas in the gas container (2) is depressurized by the pressure reducing valve (4) and flows into the gas supply path (6). To do. The first pressure sensor (25) measures the secondary pressure (p) that first flows out into the gas supply path (6), and uses this as the initial secondary pressure (p ₀ ) to calculate the arithmetic unit (29 ) And the storage unit (32) stores the initial secondary pressure (p ₀ ) as a constant.

  Next, when the fuel cell system (1) is operated, the electromagnetic valve (23) is opened, and the hydrogen gas flowing out to the gas supply path (6) is then converted into the secondary decompression pressure. The pressure is further reduced by the valve (24) and sent to the fuel cell (8), and this hydrogen gas is consumed for power generation. Due to this gas consumption, the stored gas in the gas container (2) decreases, and the residual gas pressure gradually decreases. At the same time, the secondary pressure (p) reduced by the pressure reducing valve (4) also gradually decreases. The first pressure sensor (25) measures the secondary pressure (p) as needed, and the measurement result is output to the arithmetic unit (29).

When the measurement result is output to the arithmetic unit (29), the arithmetic unit (31) outputs the secondary pressure (p), the initial container pressure (P ₀ ), and the initial secondary pressure (p ₀ ) and the decompression characteristic coefficient (α), the following equation (ii)
P = P ₀ − (p ₀ −p) ÷ α (ii)
Thus, the residual gas pressure in the gas container (2), which is the primary pressure (P), is calculated.
Specifically, for example, when the secondary pressure (p) is 0.5 MPa, the primary pressure (P) is P = 35− (0.897−0.5) ÷ 0.015≈8. 53
Thus, it can be seen from the comparison graph shown in FIG. 3 that this value is substantially correct. Then, the calculation result is output to the residual pressure display device (30) and displayed.

  The secondary pressure (p) in the gas supply path (6) is not stable while the solenoid valve (23) is open and the fuel cell (8) is operating. Therefore, the secondary pressure (p) is measured when the operation of the fuel cell (8) is stopped. On the other hand, while the fuel cell (8) is in operation, the container residual pressure calculated immediately before may be continuously displayed. Alternatively, the residual gas pressure may be estimated and displayed by calculating the consumption amount of hydrogen gas from the operating time or the like and subtracting this from the remaining gas amount measured immediately before. In this case, the displayed residual gas pressure is accurately calculated and updated by measuring the secondary pressure (p) when the operation of the fuel cell (8) is stopped next time.

When the gas consumption progresses and the residual gas pressure in the gas container (2) decreases to a predetermined limit pressure, the residual pressure display device (30) displays this and it is time to replace the container. Is notified. As a result, the gas container (2) is removed from the on-vehicle fuel cell system (1), and a new gas container (2) filled with hydrogen gas is installed in the fuel cell system (1). . The new gas container (2) and the pressure reducing valve (4) of the container valve (3) attached thereto are of the same type as the removed gas container (2) and pressure reducing valve (4). The same value is used as a constant for the initial vessel pressure (P ₀ ) and the pressure reduction characteristic coefficient (α). In addition, when the new gas container (2) is installed, the initial secondary pressure (p ₀ ) is measured and stored in the storage unit (32) as described above, and thereafter used in the same manner as the gas container. Is done.

In the above embodiment, the primary pressure (P) is calculated by the above equation (ii) using the initial secondary pressure (p ₀ ) measured by the first pressure sensor (25). However, in the present invention, instead of this, the ratio of the initial secondary pressure (p ₀ ) to the initial vessel pressure (P ₀ ) is stored in the storage unit (32) as the pressure reducing ratio (r) of the pressure reducing valve (4). Using this reduced pressure ratio (r), the following formula (iii)
P = P ₀ − (P ₀ × r−p) ÷ α (iii)
The primary pressure (P) may be calculated by That is, r = p ₀ ÷ P ₀ , and this formula (iii) is obtained by adding the initial secondary pressure (p ₀ ) of the above formula (ii) to the initial vessel pressure (P ₀ ) and the pressure reduction ratio (r ) And the product.

In the present invention, the standard initial secondary pressure (p _0S ) with respect to the initial container pressure (P ₀ ) is stored in the storage unit (32), and the standard initial secondary pressure (p _0S ) is used to Formula (i)
P = P ₀ − (p _0S −p) ÷ α (i)
The primary pressure may be calculated by

Furthermore, in the present invention, instead of the standard initial secondary pressure (p _0S ), the ratio of the standard initial secondary pressure (p _0S ) to the initial vessel pressure (P ₀ ) is changed to the pressure reducing valve (4 standard vacuum ratio) (r _S) as the storage unit stores (32), the following equation using the standard vacuum ratio (r _S) (iv)
P = P ₀ − (P ₀ × r _S −p) ÷ α (iv)
The primary pressure (P) may be calculated by That is, r _S = p _0S ÷ P ₀ , and this equation (iv) is obtained by _adding the above-mentioned initial vessel pressure (P ₀ ) and standard to the standard initial secondary pressure (p _0S ) in the above equation (i). This is a product obtained by substituting the product with the static pressure reduction ratio (r _S ).

The product of the standard initial secondary pressure (p _0S ) in the above formula (i) and the initial vessel pressure (P ₀ ) in the formula (iv) and the standard pressure reduction ratio (r _S ) If there is an assembly error etc. in 4), the actual initial secondary pressure (p ₀ ) and variation will occur. However, when the assembly error is sufficiently small, the variation is small, and even if the standard initial secondary pressure (p _0S ) is used, the primary pressure (P) in the gas container (2) The residual pressure is calculated almost accurately.

  4 and 5 show a second embodiment of the present invention, FIG. 4 is a comparison table of primary pressure and secondary pressure showing the pressure reducing characteristics of the pressure reducing valve, and FIG. 5 shows the pressure reducing characteristics of this type of pressure reducing valve. It is a contrast graph of the primary pressure and secondary pressure which shows the variation of this.

In the second embodiment, a fuel cell system (1) similar to that in the first embodiment is used, and a new gas container (2) is mounted and a gas outlet (5) of the pressure reducing valve (4) is provided. Connected to the gas supply path (6). The gas supply passage (6) is provided with a solenoid valve manifold (7), and a residual pressure measuring device (28) in the gas container (2) is provided as in the first embodiment.
However, in the second embodiment, unlike the first embodiment, a pressure reducing valve (4) in which the secondary pressure (p) increases when the primary pressure (P) decreases is used. The specific pressure reducing characteristics of the pressure reducing valve (4) are, for example, the relationship between the primary pressure (P) and the secondary pressure (p) shown in the comparison table of FIG. When the pressure-reducing characteristics of a plurality of pressure-reducing valves (4) of this type are graphed, as shown in FIG. 5, all of them are linearly inclined to the lower right, and their inclination angles are substantially equal.

From FIG. 5 above, in this type of pressure reducing valve (4), for example, when the average value is standard, the standard initial secondary pressure (p _0S ) is 0 with respect to 35 MPa which is the initial vessel pressure (P ₀ ). It is set to .48 MPa. The average value when the primary pressure (P) is 30 MPa is 0.535 MPa. Therefore, when the primary pressure (P) is reduced from 35 MPa to 5 MPa, the secondary pressure (p) is increased by 0.055 MPa, and the pressure drop of the secondary pressure (p) with respect to the pressure drop (ΔP) of the primary pressure (P). The pressure reduction characteristic coefficient (α) which is the ratio of (Δp) is −0.011. The storage unit (32) stores the decompression characteristic coefficient (α), the initial container pressure (P ₀ ), and the standard initial secondary pressure (p _0S ) in advance as constants.

Here, when the gas container (2) having the pressure reducing valve (4) having the pressure reducing characteristic shown in FIG. 4 is mounted on the fuel cell system (1), for example, the first pressure sensor (25) described above. When measuring the secondary pressure (p) of 0.6 MPa, the above calculation unit (31) is expressed by the following equation (i):
P = 35− (0.48−0.6) ÷ (−0.011) ≈24.1 (MPa)
Is calculated. On the other hand, when calculated from the comparison table shown in FIG. 4, according to the pressure reducing characteristic of the pressure reducing valve (4), when the secondary pressure (p) is 0.6 MPa, the primary pressure (P) is about 23.3 MPa. Therefore, a slight error of 0.8 MPa is generated.

Next, instead of the standard initial secondary pressure (p _0S ), the actual initial secondary pressure (p ₀ ) when the gas container (2) is mounted is measured, and this is stored in the storage unit (32). A case where the primary pressure is stored in accordance with the above equation (ii) will be described. Since the initial secondary pressure (p ₀ ) is 0.47 MPa from FIG. 4, for example, when the secondary pressure (p) is 0.6 MPa, the calculation unit (31) is expressed by the following equation (ii):
P = 35− (0.47−0.6) ÷ (−0.011) ≈23.2 (MPa)
Is calculated. As described above, according to the pressure reducing characteristic of the pressure reducing valve (4), when the secondary pressure (p) is 0.6 MPa, the primary pressure (P) is about 23.3 MPa. In this case, the error falls within a very slight error of about 0.1 MPa, and the primary pressure (P) is calculated more accurately than the calculation by the above equation (i).

  The residual pressure measuring method and residual pressure measuring device in the gas container described in the above embodiment are illustrated in order to embody the technical idea of the present invention, and the structure and arrangement of each member, the operating procedure, etc. However, the present invention is not limited to this embodiment, and various modifications can be made within the scope of the claims of the present invention.

  For example, in the above embodiment, the case where two gas containers are attached to the fuel cell system has been described. However, in the present invention, one gas container may be provided, or three or more gas containers may be provided. Moreover, when using a some gas container, taking out the gas from each gas container may be used one by one in order, and you may take out and use gas from a some gas container simultaneously. In this case, the first pressure sensor is disposed in each gas supply path connected to each gas container, and the secondary pressure of the gas supplied by reducing the pressure from each gas container is measured. The residual gas pressure inside is calculated. Further, in the above-described embodiment, the case where the pressure reducing valve is provided in the housing of the container valve has been described. However, in the present invention, this pressure reducing valve may be formed separately from the container valve and connected to the downstream side of the gas extraction path of the container valve, for example.

In each of the above embodiments, the initial container pressure is stored in advance in the storage unit. However, in the present invention, for example, as shown by the phantom line shown in FIG. 1, when the input device (33) is provided in the arithmetic unit (29) and the gas container (2) is attached, the stored gas in the gas container (2) is stored. The pressure may be input to the storage unit (32) as the initial container pressure (P ₀ ). The input means (33) can also input the pressure reducing characteristic coefficient (α) of the pressure reducing valve (4).

  In the above-described embodiment, the case where the gas consuming device is an in-vehicle fuel cell system has been described. However, the residual pressure measuring method and the residual pressure measuring device of the present invention are other gases to which a gas container is detachably attached. Needless to say, the present invention can be applied to consumer devices, and the gas stored in the gas container is not limited to hydrogen gas.

  The residual pressure measuring method and residual pressure measuring device in the gas container of the present invention can accurately calculate the residual gas pressure in the gas container, and it is not necessary to attach an electrical pressure sensor to the container valve. It can be kept small and can be implemented at low cost by reducing the required number of pressure sensors in the entire system, so it is particularly suitable for in-vehicle fuel cell systems, but gas containers can be attached and detached, including stationary fuel cell systems. It is also suitable for other gas consuming equipment to be mounted on.

1. Gas consumption equipment (fuel cell system)
2 ... Gas container 3 ... Container valve 4 ... Pressure reducing valve 5 ... Gas outlet 6 ... Gas supply path
25 ... Secondary pressure measuring means (first pressure sensor)
28 ... Residual pressure measuring device
29 ... Calculation means (arithmetic unit)
30. Residual pressure display means (residual pressure display device)
31 ... Calculation unit
32… Memory unit
33 ... Input means P ... Primary pressure P ₀ ... Initial vessel pressure ΔP ... Pressure drop of primary pressure (P) p ... Secondary pressure p ₀ ... Initial secondary pressure p _0S ... Standard initial secondary pressure Δp ... Secondary pressure pressure drop r ... decompression ratio r S _... standard vacuum ratio alpha ... decompression characteristic coefficient of (p)

Claims (11)

A container valve (3) having a pressure reducing valve (4) is attached to the gas container (2), and a gas outlet (5) of the pressure reducing valve (4) is connected to a gas supply path (6) of the gas consuming device (1). ) Is detachably connected, and a residual pressure measuring method for measuring the residual gas pressure in the gas container (2),
The stored gas pressure in the gas container (2) when connected to the gas supply path (6) is stored as an initial container pressure (P ₀ ),
The ratio of the pressure drop (Δp) of the secondary pressure (p) to the pressure drop (ΔP) of the primary pressure (P) of the pressure reducing valve (4) is stored as the pressure reducing characteristic coefficient (α) of the pressure reducing valve (4). And
Store the standard initial secondary pressure (p _0S ) set for the initial vessel pressure (P ₀ ) above,
The secondary pressure (p) fluctuated due to gas consumption is measured, the measured secondary pressure (p), the initial vessel pressure (P ₀ ), and the standard initial secondary pressure (p _0S ) From the pressure reduction characteristic coefficient (α), the following equation (i)
P = P ₀ − (p _0S −p) ÷ α (i)
The residual pressure in the gas container is calculated by calculating the residual gas pressure in the gas container (2), which is the primary pressure (P). Instead of the standard initial secondary pressure (p _0S ), the ratio of the standard initial secondary pressure (p _0S ) to the initial vessel pressure (P ₀ ) is defined as the standard of the pressure reducing valve (4). Stored as a typical pressure reduction ratio (r _S ),
The product of the standard pressure reduction ratio (r _S ) and the initial container pressure (P ₀ ) is substituted into the standard initial secondary pressure (p _0S ) of the above equation (i), and the gas container ( The method for measuring a residual pressure in a gas container according to claim 1, wherein the residual gas pressure in 2) is calculated. Instead of calculating the residual gas pressure by the above equation (i) using the above standard secondary pressure (p _0S ),
When the gas container (2) and the gas supply path (6) are connected, the secondary pressure (p) taken out from the pressure reducing valve (4) is stored as the initial secondary pressure (p ₀ ). ,
From the measured secondary pressure (p), the initial vessel pressure (P ₀ ), the initial secondary pressure (p ₀ ), and the pressure reduction characteristic coefficient (α), the following equation (ii)
P = P ₀ − (p ₀ −p) ÷ α (ii)
The residual pressure measurement method in the gas container according to claim 1, wherein the residual gas pressure in the gas container (2), which is the primary pressure (P), is calculated by: Instead of the initial secondary pressure (p ₀ ), the ratio of the initial secondary pressure (p ₀ ) to the initial container pressure (P ₀ ) is defined as the pressure reduction ratio (r) of the pressure reducing valve (4). Remember as
Substituting the product of the pressure reduction ratio (r) and the initial vessel pressure (P ₀ ) into the initial secondary pressure (p ₀ ) in the above equation (ii), the residual in the gas vessel (2) The method for measuring a residual pressure in a gas container according to claim 3, wherein the gas pressure is calculated.   The method for measuring a residual pressure in a gas container according to any one of claims 1 to 4, wherein the pressure reducing characteristic coefficient (α) of the pressure reducing valve (4) is set to be larger than zero. A container valve (3) having a pressure reducing valve (4) is attached to the gas container (2), and a gas outlet (5) of the pressure reducing valve (4) is connected to a gas supply path (6) of the gas consuming device (1). ) And is detachably connected to the residual pressure measuring device for measuring the residual gas pressure in the gas container (2),
A secondary pressure measuring means (25) attached to the gas supply path (6) for measuring the secondary pressure (p) decompressed by the pressure reducing valve (4), and the secondary pressure measuring means (25) A calculation means (29) for calculating the residual gas pressure in the gas container (2) based on the output from the above, and a residual pressure display means (30) for displaying the calculation result by the calculation means (29),
The calculation means (29) includes a calculation unit (31) and a storage unit (32),
The storage unit (32) includes an initial container pressure (P ₀ ) that is a stored gas pressure in the gas container (2) when connected to the gas supply path (6), and an initial container pressure ( The standard initial secondary pressure (p _0S ) by the pressure reducing valve (4) set for P ₀ ) and the secondary pressure (p) relative to the pressure drop (ΔP) of this primary pressure (P) The pressure reduction characteristic coefficient (α) that is the ratio of the pressure drop (Δp) is stored,
The calculation unit (31) includes the secondary pressure (p) measured by the secondary pressure measuring means (25), the initial container pressure (P ₀ ), and the standard initial secondary pressure (p _0S ) And decompression characteristic coefficient (α), the following equation (i)
P = P ₀ − (p _0S −p) ÷ α (i)
The residual pressure in the gas container is calculated by calculating the residual gas pressure in the gas container (2), which is the primary pressure (P). The storage unit (32) replaces the standard initial secondary pressure (p _0S ) with the ratio of the standard initial secondary pressure (p _0S ) to the initial vessel pressure (P ₀ ). Stored as the standard pressure reduction ratio (r _S ) of the pressure reducing valve (4) above,
The calculation unit (31) calculates the product of the standard pressure reduction ratio (r _S ) and the initial vessel pressure (P ₀ ) as the standard initial secondary pressure (p _0S ) in the above equation (i). The residual pressure measuring device in a gas container according to claim 6, wherein the residual gas pressure in the gas container (2) is calculated by substitution. The secondary pressure measuring means (25) measures the initial secondary pressure (p ₀ ) when the gas container (2) and the gas supply path (6) are connected,
It said storage unit (32), instead of the standard initial secondary pressure of the (p _0S) stores the initial secondary pressure (p _0),
The calculation unit (31) calculates the following equation (ii) from the secondary pressure (p), the initial container pressure (P ₀ ), the initial secondary pressure (p ₀ ), and the pressure reduction characteristic coefficient (α). )
P = P ₀ − (p ₀ −p) ÷ α (ii)
The residual pressure measuring device in the gas container according to claim 6, wherein the residual gas pressure in the gas container (2), which is the primary pressure (P), is calculated by the following. The storage unit (32) replaces the initial secondary pressure (p ₀ ) with the ratio of the initial secondary pressure (p ₀ ) to the initial container pressure (P ₀ ). Memorize it as decompression ratio
The calculation unit (31) substitutes the product of the pressure reduction ratio (r) and the initial container pressure (P ₀ ) for the initial secondary pressure (p ₀ ) in the above equation (ii), and The residual pressure measuring device in a gas container according to claim 8, wherein the residual gas pressure in the gas container (2) is calculated.   The residual pressure measuring device in a gas container according to any one of claims 6 to 9, wherein the pressure reducing characteristic coefficient (α) of the pressure reducing valve (4) is set to be larger than zero. Said computing means (29) comprises at least the initial container pressure (P ₀₎ input means for inputting the storage section (32) (33), according to any one of claims 6 10 For measuring the residual pressure in the gas container.

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