JP4327559B2 - Fuel filling method - Google Patents

Description

  The present invention relates to a fuel filling method for filling hydrogen gas into a fuel tank of a hydrogen gas vehicle using hydrogen gas as fuel.

Development of a hydrogen vehicle using hydrogen gas as a fuel is in progress as a next-generation vehicle. Hydrogen automobiles are characterized by low emissions of carbon dioxide, NOx, SOx, and the like.
The hydrogen vehicle travels to a supply base equipped with a fuel filling device (dispenser) for filling hydrogen gas, and replenishes the hydrogen gas with this fuel filling device in the same manner as a normal gasoline vehicle.
As a fuel tank mounted on a hydrogen vehicle, an FRP container is usually used for weight reduction. In the FRP container, the upper limit of the use temperature is defined in consideration of durability.

Unlike general gases, hydrogen gas is a gas that has the property of increasing in temperature due to the Joule-Thompson effect when adiabatically expanded. Therefore, the temperature of hydrogen gas tends to rise when it passes through devices such as valves.
When hydrogen gas is filled into the fuel tank, the temperature rises due to adiabatic compression accompanying filling in addition to the temperature rise due to the Joule-Thompson effect, so the gas temperature tends to increase.
In particular, when a fuel tank made of FRP is used, since there is an upper limit to the operating temperature, strict temperature control is required when charging hydrogen gas.

For this reason, in hydrogen automobiles, a method of filling with a predetermined time (filling time) until the end of filling in order to prevent the hydrogen gas supply flow rate from becoming excessive and to keep the fuel tank temperature below the design temperature. May be taken.
When the fuel tank capacity and the amount of hydrogen gas remaining in the fuel tank are different, the temperature of the fuel tank at the time of filling differs even when the hydrogen gas supply flow rate is constant. The filling time is set according to the size).
In addition, after the pressure in the fuel tank reaches the filling end pressure, the fuel tank temperature is lowered for a predetermined period of time, and a method of refilling with hydrogen gas corresponding to the pressure drop accompanying the temperature drop is taken. There is also.
In addition, as far as the applicant knows, none of the literature known inventions disclosed in patent applications already made by the applicant is related to the application.

However, in the above fuel filling method, it is necessary to set the filling time according to the size of the hydrogen vehicle (the size of the fuel tank), etc., so that the operation becomes complicated and the efficiency of filling work is reduced. . Further, in the method of refilling with hydrogen gas, there is a problem that the filling efficiency is lowered because the operation is complicated.
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method capable of keeping the temperature in the fuel tank low and performing fuel filling efficiently.

To solve this problem,
The invention according to claim 1 is a fuel filling method of filling hydrogen gas into a fuel tank (13) of a hydrogen gas vehicle (12) using hydrogen gas as fuel,
A fuel filling method characterized in that a filling end time (G) which is a total filling time from the start to the end of filling and a filling end pressure (F) of the fuel tank are set and the following steps are included. is there.
(1) Hydrogen gas is supplied to the fuel tank at a preset temporary filling flow rate (A) from a reference time (B) until a predetermined time has elapsed (D), and when a predetermined time has elapsed from the reference time (B) (D) The reference pressure increase rate (H) that is the pressure increase rate until is calculated as follows.
The pressure difference between the hydrogen gas pressure (E) in the fuel tank at the elapse of a predetermined time (D) and the hydrogen gas pressure (C) in the fuel tank at the reference time (B) is referred to from the time (D) at the elapse of the predetermined time. Divide the time by subtracting time (B).
(2) Calculate the necessary pressure increase rate (J) for increasing the pressure in the fuel tank to the filling end pressure (F) from the time (D) until the end of filling (G). .
(3) A required filling flow rate (K) in which the ratio to the required pressure increase rate (J) is equal to the ratio of the temporary charging flow rate (A) to the reference pressure increase rate (H) is calculated.
(4) Fill the fuel tank with hydrogen gas at the required filling flow rate (K) until the hydrogen gas pressure reaches the filling end pressure (F).
The invention according to claim 2 is the fuel filling method according to claim 1, wherein the reference time (B) is a time point after a certain time has elapsed from the start of filling.

The invention according to claim 3 is a fuel filling method of filling hydrogen gas into a fuel tank (13) of a hydrogen gas vehicle (12) using hydrogen gas as fuel,
  The filling end time (G), which is the total filling time from the start to the end of filling, and the filling end pressure (F) of the fuel tank are set, and the following steps (4) to ( 6) is a fuel filling method characterized by including one or more times.
(1) Hydrogen gas is supplied to the fuel tank at a preset temporary filling flow rate (A) from a reference time (B) until a predetermined time has elapsed (D), and when a predetermined time has elapsed from the reference time (B) (D) The reference pressure increase rate (H) that is the pressure increase rate until is calculated as follows.
    The pressure difference between the hydrogen gas pressure (E) in the fuel tank at the elapse of a predetermined time (D) and the hydrogen gas pressure (C) in the fuel tank at the reference time (B) is referred to from the time (D) at the elapse of the predetermined time. Divide the time by subtracting time (B).
(2) Calculate the necessary pressure increase rate (J) for increasing the pressure in the fuel tank to the filling end pressure (F) from the time (D) until the end of filling (G). .
(3) A required filling flow rate (K) in which the ratio to the required pressure increase rate (J) is equal to the ratio of the temporary charging flow rate (A) to the reference pressure increase rate (H) is calculated.
(4) Hydrogen gas is supplied to the fuel tank from the second reference time (B ′), which is the same time as when the predetermined time has elapsed (D), until the second predetermined time has elapsed (D ′), at the required filling flow rate (K). Then, the second reference pressure increase rate (H ′), which is the pressure increase rate from the second reference time (B ′) to the second predetermined time (D ′), is calculated as follows.
    The pressure difference between the hydrogen gas pressure (E ′) in the fuel tank at the second predetermined time (D ′) and the hydrogen gas pressure (E) in the fuel tank at the second reference time (B ′) Divide by the time obtained by subtracting the second reference time (B ′) from the time (D ′) when the predetermined time has elapsed.
(5) Second required pressure increase rate (J) for increasing the pressure in the fuel tank to the filling end pressure (F) from the time when the second predetermined time elapses (D ′) to the time when filling ends (G) ') Is calculated.
(6) Second required filling flow rate (K ′) in which the ratio to the second required pressure increase rate (J ′) is equal to the ratio of the required filling flow rate (K) to the second reference pressure increase rate (H ′). Is calculated.
(7) The fuel tank is filled with hydrogen gas at the second required filling flow rate (K ′) until the hydrogen gas pressure reaches the filling end pressure (F).

The invention according to claim 4 is the fuel filling method according to claim 1, characterized in that it includes the following step (8) instead of the step (4).
(8) When the required filling flow rate (K) is equal to or greater than the lower limit value of the preset setting range, the hydrogen gas is changed to the filling end pressure (F) at the necessary filling flow rate (K). Fill the fuel tank until it reaches,
  When the required filling flow rate (K) is less than the lower limit value, hydrogen gas is filled into the fuel tank at a filling flow rate equal to or higher than the lower limit value until the hydrogen gas pressure reaches the filling end pressure (F).
  The invention according to claim 5 is a fuel filling method for filling hydrogen gas into a fuel tank (13) of a hydrogen gas vehicle (12) using hydrogen gas as a fuel, and includes the following steps: This is a fuel filling method.
(1) The pressure difference between the actual fuel tank pressure (Pn) at the reference time (tn) and the virtual fuel tank pressure (Pn ′) calculated on the assumption that there is no temperature change during filling ( ΔPn) is calculated.
(2) The actual pressure (Pn + 1) of the fuel tank at the time (tn + 1) when a predetermined time has elapsed from the reference time (tn), and the virtual pressure of the fuel tank calculated on the assumption that there is no temperature change during filling The pressure difference (ΔPn + 1) from (Pn + 1 ′) is calculated.
(3) When the pressure difference (ΔPn + 1) at the elapse of a predetermined time (tn + 1) is smaller than the pressure difference (ΔPn) at the reference time (tn), the hydrogen gas supply flow rate is maintained or increased,
When the pressure difference (ΔPn + 1) at the elapse of a predetermined time (tn + 1) is equal to or larger than the pressure difference (ΔPn) at the reference time (tn), the hydrogen gas supply flow rate is reduced.

In the fuel filling method of the present invention, the required filling flow rate is calculated based on the pressure increase rate when hydrogen gas is supplied at the temporary filling flow rate, and the filling is performed until the filling is completed at this necessary filling flow rate. The required filling flow rate that is the optimum value according to the filling time can be corrected, and the filling efficiency can be increased.
Moreover, since the supply flow rate can be corrected to a low value when the temporary filling flow rate is too large, the temperature in the fuel tank can be prevented from becoming too high, and the safety can be improved.

By setting the reference time as a time when a certain time has elapsed from the start of filling, the initial filling stage that may be in an unsteady state can be excluded from the measurement target.
Therefore, the hydrogen gas supply flow rate can be optimized with high accuracy.

In the fuel filling method of the present invention, the pressure difference between the actual pressure and the virtual pressure at the reference time is compared with the pressure difference at the predetermined time, and the pressure difference at the predetermined time is smaller than the pressure difference at the reference time. In this case, since the hydrogen gas supply flow rate is maintained or increased, the charging efficiency can be increased.
In addition, when the pressure difference when the predetermined time elapses is equal to or larger than the pressure difference at the reference time, the hydrogen gas supply flow rate is reduced, so that an excessive temperature rise can be prevented.
Therefore, filling efficiency can be increased without sacrificing safety.
Further, when the effect of the temperature rise factor is large, this can be suppressed and the temperature of the fuel tank can be kept low.
Therefore, the pressure drop of the fuel tank due to the temperature drop after the completion of filling can be minimized, and refilling can be made unnecessary. For this reason, filling work can be facilitated and filling efficiency can be increased.

FIG. 2 shows a fuel filling apparatus capable of implementing the first example of the fuel filling method of the present invention.
The fuel filling device 1 shown here includes a supply path 3 for supplying hydrogen gas from a hydrogen gas storage tank 2, an integrated flow meter F1 for detecting and integrating the flow rate of hydrogen gas, and a flow rate adjustment for adjusting the flow rate of hydrogen gas. The valve V1, the control means 5 which controls the supply amount of hydrogen gas, the cutoff valve V2 provided in the supply path 3, and the heat exchanger 4 which cools hydrogen gas are provided.
The supply path 3 includes a first and a second temperature for detecting a hydrogen gas temperature on the primary side (upstream side in the hydrogen gas flow direction) and the secondary side (downstream side in the hydrogen gas flow direction), respectively. A total of 6 and 7 are provided.
In the supply path 3, on the secondary side of the heat exchanger 4, a filling gas thermometer 8 (temperature detection means) for detecting the temperature of the hydrogen gas to be filled, and a pressure gauge for detecting the pressure of the hydrogen gas to be filled 9 (pressure detection means).

The heat exchanger 4 includes a hydrogen gas circulation pipe 4a that circulates hydrogen gas, and the hydrogen gas in the hydrogen gas circulation pipe 4a can be cooled by a refrigerant.
The control means 5 can control the hydrogen gas supply flow rate by adjusting the opening degree of the flow rate adjusting valve V1 based on the detected value of the flow meter F1.

One end of a connecting pipe 11 such as a flexible hose for supplying hydrogen gas to the hydrogen automobile 12 is connected to the end of the supply path 3.
The other end of the communication pipe 11 can be connected to the supply path 14 of the hydrogen automobile 12 via a coupler (not shown).
Reference sign V3 is a check valve provided in the supply path 14 of the hydrogen automobile 12, and prevents the fuel in the fuel tank 13 from leaking outside.

Hereinafter, a first example of the fuel filling method of the present invention will be described.
As shown in FIG. 2, after connecting the connecting pipe 11 to the hydrogen vehicle 12 that has visited the fuel filling device 1 for fuel filling, the shutoff valve V <b> 2 is opened and hydrogen gas from the storage tank 2 is introduced into the supply path 3. To do. The supply flow rate of hydrogen gas can be adjusted to an appropriate value by the flow rate adjustment valve V1.
The hydrogen gas passes through the heat exchanger 4 and is filled into the fuel tank 13 through the communication pipe 11 and the supply path 14.

Hereinafter, an example of the operation of filling the fuel tank 13 with hydrogen gas will be described in detail.
In this fuel filling method, prior to the operation shown below, a filling end time G (min), which is a total filling time from the filling start to the end, and a fuel tank filling end pressure F (MPa) are set. In this example, the filling end pressure F = 35 (MPa), and the filling end pressure G = 10 (min).
In the operation described below, the opening degree of the flow rate adjusting valve V1 is adjusted by the control means 5 based on the hydrogen gas pressure in the fuel tank 13 detected by the pressure gauge 9 and the hydrogen gas flow rate detected by the flow meter F1. As a result, the flow rate of the hydrogen gas is controlled. As a control method, it is preferable to employ PID control.

(1) Calculation of reference pressure increase rate As shown in FIG. 1, by adjusting the opening degree of the flow rate adjusting valve V1 based on the detected value of the flow meter F1, hydrogen gas is preliminarily charged with a preliminarily charged flow rate A ( g / min) to the fuel tank. In this example, A = 450 (g / min).
Next, in the control means 5, a reference pressure increase rate H (MPa) which is a pressure increase rate from a reference time B (when B seconds have elapsed from the start of filling) to a time D (when D seconds have elapsed from the start of filling) has elapsed. / Min).
In the initial stage of filling, the measurement value may be disturbed due to a disturbance due to disturbance, so it is preferable to remove this initial stage from the measurement target. For this reason, it is preferable that the reference time B (sec) is a time when a certain time (for example, 1 second or more) has elapsed since the start of filling.

The reference pressure increase rate H (MPa / min) can be calculated according to the following equation.
H = (E−C) / ((D−B) / 60)
In this equation, the reference pressure C (MPa) is the hydrogen gas pressure in the fuel tank 13 at the reference time B (sec). The adjustment pressure E (MPa) is the hydrogen gas pressure in the fuel tank 13 at a predetermined time D (sec).
The reference pressure C and the adjustment pressure E can be detected by the pressure gauge 9.
In this example, reference time B = 10 (sec), elapse of a predetermined time D = 40 (sec), reference pressure C = 5 (MPa), and adjustment pressure E = 6.3 (MPa). The reference pressure increase rate H is 2.6 (MPa / min).

(2) Calculation of required pressure increase rate The hydrogen gas pressure in the fuel tank 13 is increased to the filling end pressure F (MPa) between the time D (sec) when the predetermined time has elapsed and the time G (min) at the end of filling. A required pressure increase rate J (MPa / min), which is a hydrogen gas pressure increase rate, is calculated as follows.
First, a required pressure increase width I (MPa) from an adjustment pressure E (MPa) to a filling end pressure F (MPa) at a predetermined time D (sec) is obtained.
I = FE
Next, a required pressure increase rate J (MPa / min), which is a pressure increase rate necessary to obtain the required pressure increase width I (MPa) at the end of filling G (min), is calculated according to the following equation.
J = I / (G × 60−D) / 60
In this example, the required pressure increase rate J = 3.1 (MPa / min).

(3) Calculation of required filling flow rate In this step, the required filling flow rate K (g / min), which is the supply flow rate of hydrogen gas necessary for obtaining the required pressure increase rate J (MPa / min), is expressed as follows. Calculate using the formula.
H: A = J: K
This relational expression means that the ratio between the reference pressure increase rate H and the temporary filling flow rate A is equal to the ratio between the required pressure increase rate J and the required filling flow rate K.
Based on the assumption that this relational expression holds, the required filling flow rate K (g / min) is calculated according to the following formula.
K = A × J / H
The required filling flow rate K is a value in which the ratio to the required pressure increase rate J is equal to the ratio of the temporary filling flow rate A to the reference pressure increase rate H. In this example, the required filling flow rate K = 532.2 (g / min).

(4) Charging at the required filling flow rate Hydrogen gas is filled into the fuel tank 13 at the required filling flow rate K (g / min) until the hydrogen gas pressure reaches the filling end pressure F (MPa).

In this fuel filling method, the necessary filling flow rate K is calculated based on the pressure increase rate H when hydrogen gas is supplied at the temporary filling flow rate A, and filling is performed until the filling is completed at this necessary filling flow rate K (g / min). .
In this method, since the hydrogen gas supply flow rate can be corrected to the required filling flow rate K (g / min) that is an optimum value according to the filling time, the filling efficiency can be increased.
Moreover, since the supply flow rate can be corrected to a low value when the temporary filling flow rate A is too large, it is possible to prevent the temperature in the fuel tank 13 from becoming too high and improve safety.

In addition, by setting the reference time B as a time when a certain time has elapsed from the start of filling, the initial filling stage that may be in an unsteady state can be excluded from the measurement target.
Therefore, the hydrogen gas supply flow rate can be optimized with high accuracy.

Next, a second example of the fuel filling method of the present invention will be described with reference to FIG.
In this method , the following steps (4) to (7) are performed after the step (3).
( 4 ) Hydrogen gas is supplied to the fuel tank 13 at the required filling flow rate K, and a second reference pressure increase rate H ′ that is a pressure increase rate from the second reference time B ′ to the time D ′ when the second predetermined time has elapsed is obtained. calculate.
The second reference pressure increase rate H ′ can be calculated in the same manner as in the above step (1).
In the example shown in FIG. 3, the time D when the predetermined time elapses in the example shown in FIG. 1 is set as the second reference time B ′.

( 5 ) The second increase rate of the hydrogen gas required to increase the hydrogen gas pressure in the fuel tank to the filling end pressure F between the second predetermined time D 'and the filling end time G. The required pressure increase rate J ′ is calculated.
The second necessary pressure increase rate J ′ can be calculated in the same manner as in the above step (2).

( 6 ) The second required filling flow rate K ′ is calculated such that the ratio to the second required pressure increase rate J ′ is equal to the ratio of the required filling flow rate K to the second reference pressure increase rate H ′.
The second necessary filling flow rate K ′ can be calculated in the same manner as in the step (3).

Subsequent to the step ( 6 ), as the step (7), an operation of filling the fuel tank 13 with the hydrogen gas at the second necessary filling flow rate K ′ until the hydrogen gas pressure reaches the filling end pressure F (MPa). Do.
In the method of this example, steps (4) to (6) can be performed twice or more.

According to this method, since steps (5) to (7) are included, the hydrogen gas supply flow rate is corrected a plurality of times in the hydrogen gas supply process.
For this reason, even when the required filling flow rate K becomes excessively low or excessive due to an unexpected factor such as a change in the outside air temperature, it can be corrected to the second required charging flow rate K ′ which is an optimum value.
Accordingly, the hydrogen gas supply flow rate can be accurately set to an optimal value, the charging efficiency can be increased, the temperature in the fuel tank 13 can be reliably prevented from becoming too high, and safety can be improved.

Next, a third example of the fuel filling method of the present invention will be described.
In the above method, the necessary filling flow rate K is set on the assumption that the internal pressure of the fuel tank 13 reaches the filling end pressure F at the end of filling G.
For this reason, when the adjustment pressure E at a predetermined time D is a high value, the required pressure increase width I becomes small, and the required filling flow rate K is a very low value, that is, a value that is safer than necessary. May be. In such a case, the filling flow rate can be set to a value higher than the necessary filling flow rate K.
That is, in this invention, it can replace with process (4) and can perform the following process (8).
(8) When the required filling flow rate K is equal to or higher than the lower limit value of the preset setting range, the fuel tank 13 is filled with hydrogen gas until the filling end pressure F is reached at the necessary filling flow rate K.
When the necessary filling flow rate K is less than the lower limit value, hydrogen gas is filled into the fuel tank 13 until the filling end pressure F is reached at a filling flow rate equal to or higher than the lower limit value.
When the required filling flow rate K is less than the lower limit value, the filling flow rate is preferably set to be equal to or higher than the temporary filling flow rate A.

Hereinafter, a specific example is shown with reference to FIG. 1 and FIG.
As shown in FIG. 1, when the required filling flow rate K is in the range of the temporary filling flow rate A or more, hydrogen gas is filled in the fuel tank 13 until the filling end pressure F is reached at the necessary filling flow rate K.
As shown in FIG. 4, when the required filling flow rate K is less than the temporary filling flow rate A, hydrogen gas is filled into the fuel tank 13 until the filling end pressure F is reached at the temporary filling flow rate A.
According to this method, when the necessary filling flow rate K is less than the temporary filling flow rate A, it is possible to prevent the filling efficiency from being lowered.

In this method, in order to prevent the hydrogen gas temperature from becoming excessively high, it is preferable to set an upper limit value in the setting range.
That is, when the required filling flow rate K exceeds the upper limit value, hydrogen gas can be filled in the fuel tank 13 up to the filling end pressure F at a filling flow rate equal to or lower than the upper limit value.
According to this method, it is possible to prevent the temperature in the fuel tank 13 from rising excessively and to improve safety.

Next, a fourth example of the fuel filling method of the present invention will be described.
As shown in FIG. 5, using the fuel filling apparatus 1, the pressure P in the fuel tank 13 is filled with hydrogen gas to reach the adjustment when the pressure P _A to the fuel tank 13 (step S1).
The pressure P _A is preferably set to a value close to the filling completion pressure. For example, when the filling completion pressure is 35MPa, the adjustment time of the pressure _{P A} may be 30 MPa.
Although the pressure P in the fuel tank 13 cannot be measured directly because of the check valve V3, the hydrogen gas supply flow rate detected by the integrated flow meter F1 at the beginning of the hydrogen gas supply start and the hydrogen gas detected by the pressure meter 9 It can be calculated based on the gas pressure.
Hereinafter, the actual pressure in the fuel tank 13 obtained from the value detected by the pressure gauge 9 may be referred to as an actual pressure.

(1) the difference between the actual pressure and the virtual pressure as shown in the calculation diagram 5 and FIGS. 6 (a) at the reference time, the actual pressure P is adjusted at the pressure P _{A (e.g.} 30 MPa) reached the time t (filling start the elapsed time) from the t _n is the time reference, to the actual pressure P at this time the actual pressure P _n (step S2).
At this time, the opening degree of the flow rate adjusting valve V1 is set to 0% by the control means 5 (step S3).
The opening of the flow rate adjusting valve V1 is 100% when it is the maximum, and 0% when it is closed.

In this fuel filling method, the control means 5 does not consider the temperature change in the fuel tank 13, and based on only the integrated value of the hydrogen gas flow rate calculated by the integrated flow meter F 1 and the capacity of the fuel tank 13, the time t _A virtual pressure P _n ′ that is the pressure of the fuel tank 13 at _n is calculated. The capacity of the fuel tank 13 can be determined based on the hydrogen gas supply flow rate and the pressure change in the fuel tank 13. For example, as shown in the above first example, it can be determined based on the temporary filling flow rate A, the reference pressure C, and the adjustment pressure E.
The virtual pressure P _n ′ is calculated based only on the integrated value of the hydrogen gas flow rate (actually filled hydrogen gas amount) and the tank capacity, and is therefore a value proportional to the filled hydrogen gas amount. .
This virtual pressure P _n ′ corresponds to a pressure when it is assumed that there is no temperature change during filling, and is usually a value lower than the actual pressure P _n .
On the other hand, the actual pressure P does not normally have a value proportional to the amount of hydrogen gas charged because of the pressure increase associated with gas filling and the temperature rise due to the Joule-Thompson effect.
Based on the following equation, a pressure difference ΔP (ΔP _n ) that is a difference between the actual pressure P _n and the virtual pressure P _n ′ is calculated.
ΔP _n = P _n −P _n ′
This pressure difference ΔP _n becomes larger as the temperature rise during filling is larger.

(2) calculating a difference between the actual pressure and the virtual pressure when a predetermined time has elapsed then measured the actual pressure P at time t _{n + 1} is the time at which a predetermined time has elapsed from the time t _n (for example, one minute), this actual The pressure is set to P _{n + 1} (step S4).
The virtual pressure at this time is defined as P _{n + 1} ′.
Next, a pressure difference ΔP (ΔP _{n + 1} ), which is a difference between the actual pressure P _{n + 1} and the virtual pressure P _{n + 1} ′, is calculated based on the following equation (step S5).
ΔP _{n + 1} = P _{n + 1} −P _{n + 1} ′

(3) Comparing the pressure difference between the reference time and the lapse of a predetermined time In this fuel filling method, the pressure difference ΔP _n is compared with the pressure difference ΔP _{n + 1,} and if the following equation (a) is satisfied, the flow rate The opening degree of the regulating valve V1 is increased (steps S6 and S7).
ΔP _n > ΔP _{n + 1} (a)
When increasing the degree of opening of the flow regulating valve V1, compared opening of flow control valve V1 at time t _n, take the way to the opening of flow control valve V1 larger predetermined value (e.g. 1%) it can.
By increasing the opening degree of the flow rate adjusting valve V1, the hydrogen gas supply flow rate is increased and the charging efficiency is increased.

In the fuel tank 13, pressure increase due to filling, the Joule-Thompson effect, and the like act as temperature rise factors, while heat radiation to the outside air acts as a temperature fall factor.
The establishment of the expression (a) means that the actual pressure P has approached the virtual pressure because the action of the temperature lowering factor exceeds the action of the temperature increasing factor at the time t _{n to} t _{n + 1} .
When equation (a) is satisfied, the effect of the temperature rise factor is small, and therefore, even if the opening degree of the flow rate adjustment valve V1 is increased, an excessive temperature rise is unlikely to occur.

Next, as shown in FIG. 5 and FIG. 6B, the above-described operation is repeated with the time point t _{n + 1} when the opening degree of the flow rate adjustment valve V1 is increased as a reference time.
That is, a pressure difference ΔP between the actual pressure when a predetermined time (for example, 1 minute) has elapsed from the reference time and the virtual pressure at this time is calculated and compared with ΔP at the reference time. When the pressure difference ΔP when the predetermined time has elapsed is smaller than the reference pressure difference ΔP, the opening degree of the flow rate adjustment valve V1 is increased.
When the pressure difference ΔP when the predetermined time elapses is smaller than the reference pressure difference ΔP, the opening degree of the flow regulating valve V1 can be kept constant without being changed.

On the other hand, as shown in FIGS. 5 and 6C, when the formula (a) is not satisfied, that is, when the pressure difference ΔP _{n + 1} when the predetermined time elapses is equal to or larger than the pressure difference ΔP _n at the reference time It is considered that the action of the temperature increase factor is equal to or exceeds the action of the temperature decrease factor at the time t _{n to} t _{n + 1} .
For this reason, when Formula (a) is not materialized, the opening degree of the flow regulating valve V1 is made small. In the illustrated example, the opening degree of the flow rate adjustment valve V1 is set to 0% (step S3).
When reducing the opening degree of the flow rate adjustment valve V1, a method of reducing the opening degree of the flow rate adjustment valve V1 by a predetermined value (for example, 1%) compared to the opening degree of the flow rate adjustment valve V1 at time t _n (reference time). You can also take In this case, as shown by a broken line in FIG. 5, when formula (a) is not satisfied, a method of returning to step S4 can be taken.

  By reducing the opening degree of the flow rate adjusting valve V1, the hydrogen gas supply flow rate can be reduced, the effects of temperature rise factors (pressure rise due to filling and Joule-Thompson effect) can be suppressed, and excessive temperature rise can be prevented.

Next, the above-described operation is repeated with time t _{n + 1} when the opening of the flow rate adjustment valve V1 is reduced as a reference time. That is, the pressure difference ΔP between the actual pressure when a predetermined time (for example, 1 minute) has elapsed from the reference time and the virtual pressure at this time is calculated and compared with the pressure difference ΔP at the reference time.

In this fuel filling process, the reference time _t actual pressure in the _{n P n} and the pressure difference [Delta] P _n of the virtual pressure _{P n} ', compared with the pressure difference [Delta] P _{n + 1} in the predetermined time when _{t n + 1,} the pressure difference [Delta] P _{n + 1} since the hydrogen gas supply flow rate maintained or increased if smaller than the pressure difference [Delta] P _n, it is possible to increase the charging efficiency.
Further, when the pressure difference ΔP _{n + 1} is equal to or larger than the pressure difference ΔP _n , the hydrogen gas supply flow rate is reduced, so that excessive temperature rise can be prevented.
Therefore, filling efficiency can be increased without sacrificing safety.
Further, when the effect of the temperature rise factor is large, this can be suppressed and the temperature of the fuel tank 13 can be kept low.
For this reason, the pressure drop of the fuel tank 13 resulting from the temperature drop after completion | finish of filling can be suppressed to the minimum, and refilling can be made unnecessary. Therefore, the filling operation can be facilitated and the filling efficiency can be increased.

In the present invention, when the pressure difference ΔP when the predetermined time has elapsed is equal to the pressure difference ΔP at the reference time, the opening degree of the flow regulating valve V1 can be kept constant without being changed.
In this case, when the pressure difference ΔP when the predetermined time elapses is smaller than the pressure difference ΔP at the reference time, the hydrogen gas supply flow rate is increased, and the pressure difference when the predetermined time elapses becomes the pressure difference at the reference time. When the comparison is larger, a method of reducing the hydrogen gas supply flow rate can be taken.

It is a figure explaining the 1st example of the fuel filling method of this invention. It is a schematic block diagram which shows an example of the fuel filling apparatus which can implement the fuel filling method of this invention. It is a figure explaining the 2nd example of the fuel filling method of this invention. It is a figure explaining the 3rd example of the fuel filling method of this invention. It is a flowchart explaining the 4th example of the fuel filling method of this invention. It is a figure explaining the 4th example of the fuel filling method of this invention.

Explanation of symbols

1 ... Fuel filling device,
5 ... Control means,
9 ... Pressure gauge,
12 ... Hydrogen car,
13 ... Fuel tank,
V1 ... Flow control valve,
F1 ... Integral flow meter,
G: At the end of filling,
F: Filling end pressure,
A: Temporary filling flow rate,
B ... Reference time,
D: When a predetermined time has elapsed,
K: Necessary filling flow rate,
B ′ ・ ・ ・ Second reference time,
D ′ ・ ・ ・ When the second predetermined time has elapsed,
K ′ ・ ・ ・ Second required filling flow rate,
t _n ... reference time,
t _{n + 1} ... when a predetermined time has elapsed,
_Pn : actual pressure at the reference time,
P _n '・ ・ ・ virtual pressure at reference time,
ΔP _n : Pressure difference between the actual pressure and the virtual pressure at the reference time,
P _{n + 1} ... the actual pressure when a predetermined time has elapsed,
P _{n + 1} '・ ・ ・ virtual pressure when a predetermined time has elapsed,
ΔP _{n + 1} ... Pressure difference between actual pressure and virtual pressure when a predetermined time has elapsed

Claims (5)

A fuel filling method for filling a fuel tank (13) of a hydrogen gas vehicle (12) using hydrogen gas as a fuel, with hydrogen gas,
A fuel filling method characterized in that a filling end time (G) which is a total filling time from the start to the end of filling and a filling end pressure (F) of a fuel tank are set, and the following steps are included.
(1) Hydrogen gas is supplied to the fuel tank at a preset temporary filling flow rate (A) from a reference time (B) until a predetermined time has elapsed (D), and when a predetermined time has elapsed from the reference time (B) (D) The reference pressure increase rate (H) that is the pressure increase rate until is calculated as follows.
The pressure difference between the hydrogen gas pressure (E) in the fuel tank at the elapse of a predetermined time (D) and the hydrogen gas pressure (C) in the fuel tank at the reference time (B) is referred to from the time (D) at the elapse of the predetermined time. Divide the time by subtracting time (B).
(2) Calculate the necessary pressure increase rate (J) for increasing the pressure in the fuel tank to the filling end pressure (F) from the time (D) until the end of filling (G). .
(3) A required filling flow rate (K) in which the ratio to the required pressure increase rate (J) is equal to the ratio of the temporary charging flow rate (A) to the reference pressure increase rate (H) is calculated.
(4) Fill the fuel tank with hydrogen gas at the required filling flow rate (K) until the hydrogen gas pressure reaches the filling end pressure (F).   2. The fuel filling method according to claim 1, wherein the reference time (B) is a time point after a predetermined time has elapsed since the start of filling. A fuel filling method for filling a fuel tank (13) of a hydrogen gas vehicle (12) using hydrogen gas as a fuel, with hydrogen gas,
  A fuel filling method characterized in that a filling end time (G) which is a total filling time from the start to the end of filling and a filling end pressure (F) of a fuel tank are set, and the following steps are included.
(1) Hydrogen gas is supplied to the fuel tank at a preset temporary filling flow rate (A) from a reference time (B) until a predetermined time has elapsed (D), and when a predetermined time has elapsed from the reference time (B) (D) The reference pressure increase rate (H) that is the pressure increase rate until is calculated as follows.
    The pressure difference between the hydrogen gas pressure (E) in the fuel tank at the elapse of a predetermined time (D) and the hydrogen gas pressure (C) in the fuel tank at the reference time (B) is referred to from the time (D) at the elapse of the predetermined time. Divide the time by subtracting time (B).
(2) Calculate the necessary pressure increase rate (J) for increasing the pressure in the fuel tank to the filling end pressure (F) from the time (D) until the end of filling (G). .
(3) A required filling flow rate (K) in which the ratio to the required pressure increase rate (J) is equal to the ratio of the temporary charging flow rate (A) to the reference pressure increase rate (H) is calculated.
(4) Hydrogen gas is supplied to the fuel tank from the second reference time (B ′), which is the same time as when the predetermined time has elapsed (D), until the second predetermined time has elapsed (D ′), at the required filling flow rate (K). Then, the second reference pressure increase rate (H ′), which is the pressure increase rate from the second reference time (B ′) to the second predetermined time (D ′), is calculated as follows.
    The pressure difference between the hydrogen gas pressure (E ′) in the fuel tank at the second predetermined time (D ′) and the hydrogen gas pressure (E) in the fuel tank at the second reference time (B ′) Divide by the time obtained by subtracting the second reference time (B ′) from the time (D ′) when the predetermined time has elapsed.
(5) Second required pressure increase rate (J) for increasing the pressure in the fuel tank to the filling end pressure (F) from the time when the second predetermined time elapses (D ′) to the time when filling ends (G) ') Is calculated.
(6) Second required filling flow rate (K ′) in which the ratio to the second required pressure increase rate (J ′) is equal to the ratio of the required filling flow rate (K) to the second reference pressure increase rate (H ′). Is calculated.
(7) The fuel tank is filled with hydrogen gas at the second required filling flow rate (K ′) until the hydrogen gas pressure reaches the filling end pressure (F). 2. The fuel filling method according to claim 1, further comprising the following step (8) instead of the step (4).
(8) When the required filling flow rate (K) is equal to or greater than the lower limit value of the preset setting range, the hydrogen gas is changed to the filling end pressure (F) at the necessary filling flow rate (K). Fill the fuel tank until it reaches,
  When the required filling flow rate (K) is less than the lower limit value, hydrogen gas is filled into the fuel tank at a filling flow rate equal to or higher than the lower limit value until the hydrogen gas pressure reaches the filling end pressure (F). A fuel filling method for filling hydrogen gas into a fuel tank (13) of a hydrogen gas vehicle (12) using hydrogen gas as a fuel, the method including the following steps.
(1) The pressure difference between the actual fuel tank pressure (Pn) at the reference time (tn) and the virtual fuel tank pressure (Pn ′) calculated on the assumption that there is no temperature change during filling ( ΔPn) is calculated.
(2) The actual pressure (Pn + 1) of the fuel tank at the time (tn + 1) after a predetermined time has elapsed from the reference time (tn) and the virtual pressure of the fuel tank calculated on the assumption that there is no temperature change during filling The pressure difference (ΔPn + 1) from (Pn + 1 ′) is calculated.
(3) When the pressure difference (ΔPn + 1) at the elapse of a predetermined time (tn + 1) is smaller than the pressure difference (ΔPn) at the reference time (tn), the hydrogen gas supply flow rate is maintained or increased,
When the pressure difference (ΔPn + 1) at the elapse of a predetermined time (tn + 1) is equal to or larger than the pressure difference (ΔPn) at the reference time (tn), the hydrogen gas supply flow rate is reduced.

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