U.S. patent application number 13/387673 was filed with the patent office on 2012-05-24 for gas filling system and gas filling apparatus.
This patent application is currently assigned to TOYOTA JIDOSHA KABUSHIKI KAISHA. Invention is credited to Shusuke Inagi, Tomoyuki Mori.
Application Number | 20120125480 13/387673 |
Document ID | / |
Family ID | 42359543 |
Filed Date | 2012-05-24 |
United States Patent
Application |
20120125480 |
Kind Code |
A1 |
Inagi; Shusuke ; et
al. |
May 24, 2012 |
GAS FILLING SYSTEM AND GAS FILLING APPARATUS
Abstract
A gas filling apparatus in the gas filling system includes a
precooler for cooling hydrogen gas supplied from the gas supply
source (11) and discharges the hydrogen gas cooled by the precooler
to fill the hydrogen gas into the gas tank. The temperature of the
hydrogen gas cooled by the precooler is detected by a gas
temperature sensor that detects, upstream of the gas tank, a
temperature of the hydrogen gas cooled by the precooler. A flow
rate controller controls a filling flow rate of the hydrogen gas to
be filled into the gas tank, based on the detected temperature of
the hydrogen gas. For example, when the detected temperature of the
hydrogen gas is high, the filling flow rate is reduced as compared
to that when the detected temperature of the hydrogen gas is
lower.
Inventors: |
Inagi; Shusuke;
(Okazaki-shi, JP) ; Mori; Tomoyuki; (Toyota-shi,
JP) |
Assignee: |
TOYOTA JIDOSHA KABUSHIKI
KAISHA
Toyota-shi
JP
|
Family ID: |
42359543 |
Appl. No.: |
13/387673 |
Filed: |
June 17, 2010 |
PCT Filed: |
June 17, 2010 |
PCT NO: |
PCT/IB10/01470 |
371 Date: |
January 27, 2012 |
Current U.S.
Class: |
141/4 ;
141/82 |
Current CPC
Class: |
F17C 2270/0184 20130101;
F17C 2250/0439 20130101; F17C 2221/012 20130101; F17C 2250/043
20130101; F17C 2250/0495 20130101; F17C 2227/0355 20130101; F17C
2250/0636 20130101; F17C 5/06 20130101; F17C 2205/0335 20130101;
F17C 2205/0134 20130101; F17C 2223/036 20130101; Y02P 90/45
20151101; F17C 2227/0341 20130101; F17C 2205/035 20130101; F17C
2260/025 20130101; F17C 2250/075 20130101; Y02E 60/32 20130101;
F17C 2205/0376 20130101; F17C 2225/036 20130101; F17C 2265/065
20130101; F17C 2227/0388 20130101; F17C 2250/0443 20130101; F17C
2201/056 20130101; F17C 2205/0326 20130101; F17C 2250/032 20130101;
F17C 2227/0157 20130101; F17C 2223/0123 20130101; Y02E 60/321
20130101; F17C 2270/0168 20130101; F17C 2225/0123 20130101 |
Class at
Publication: |
141/4 ;
141/82 |
International
Class: |
B65B 57/00 20060101
B65B057/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 30, 2009 |
JP |
2009-177499 |
Claims
1. A gas filling system comprising: a gas tank; a gas filling
apparatus, including a cooling device for cooling gas supplied from
a gas supply source, that discharges the gas cooled by the cooling
device to fill the gas into the gas tank; a gas tank sensor that
acquires information concerning the inside of the gas tank; a gas
temperature sensor that detects, upstream of the gas tank, a
temperature of the gas cooled by the cooling device; and a flow
rate controller that controls a filling flow rate of the gas to be
filled into the gas tank, based on the temperature of the gas
detected by the gas temperature sensor and the information obtained
by the gas tank sensor.
2. The gas filling system according to claim 1, wherein the flow
rate controller controls the filling flow rate so that the filling
flow rate is reduced as the temperature of the gas increases.
3. (canceled)
4. The gas filling system according to claim 1, wherein the gas
tank sensor includes at least one of a gas tank temperature sensor
and a gas tank pressure sensor.
5. The gas filling system according to claim 1, wherein: the gas
filling system includes a plurality of the gas tanks; the gas tank
sensor acquires the information for each of the gas tanks; and the
flow rate controller controls the filling flow rate based on the
information on the gas tank, in which a temperature is the highest,
or on the information on the gas tank, in which a pressure is the
lowest, among pieces of the information acquired by the gas tank
sensors.
6. The gas filling system according to claim 1, wherein the gas
temperature sensor detects the temperature of the gas in the
cooling device.
7. The gas filling system according to claim 1, wherein the gas
temperature sensor detects the temperature of the gas after being
discharged from the gas filling apparatus to the gas tank.
8. The gas filling system according to claim 1, further comprising
a connection unit for connecting the gas tank and the gas filling
apparatus at the time of filling, wherein the gas temperature
sensor detects the temperature of the gas at the connection
unit.
9. The gas filling system according to claim 8, wherein: the
connection unit includes a receptacle on the gas tank side and a
filling nozzle on the gas filling apparatus side that is connected
to the receptacle; and the gas temperature sensor detects the
temperature of the gas at the filling nozzle.
10. The gas filling system according to claim 8, wherein: the
connection unit includes a receptacle on the gas tank side and a
filling nozzle on the gas filling apparatus side that is connected
to the receptacle; and the gas temperature sensor detects the
temperature of the gas at the receptacle.
11. The gas filling system according to claim 1, further comprising
a display device that displays an indication that the filling flow
rate is being controlled based on the temperature of the gas
detected by the gas temperature sensor or an indication that the
filling flow rate has been controlled based on the temperature of
the gas detected by the gas temperature sensor.
12. The gas filling system according to claim 11, wherein the
display device is provided in the gas filling apparatus.
13. The gas filling system according to claim 11, wherein the
display device is provided in a mobile body, on which the gas tank
is mounted.
14. A gas filling apparatus, including a cooling device for cooling
gas supplied from a gas supply source, that discharges the gas
cooled by the cooling device to fill the gas into the gas tank, the
gas filling apparatus comprising: a gas tank information
acquisition portion that acquires information concerning the inside
of the gas tank; a gas temperature sensor that detects, upstream of
the gas tank, a temperature of the gas cooled by the cooling
device; and a flow rate controller that controls a filling flow
rate of the gas to be filled into the gas tank, based on the
temperature of the gas detected by the gas temperature sensor and
the information obtained by the gas tank information acquisition
portion.
15. A method for controlling filling of gas supplied from a gas
supply source into a gas tank, comprising: detecting, upstream of
the gas tank, a temperature of the gas cooled by a cooling device;
acquiring information concerning the inside of the gas tank; and
controlling a filling flow rate of the gas to be filled into the
gas tank, based on the detected temperature of the gas and the
information on the inside of the gas tank.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The invention relates to a gas filling system for filling
gas via a gas filling apparatus installed in a hydrogen station,
for example, into a gas tank mounted on a vehicle, for example.
[0003] 2. Description of the Related Art
[0004] At the time of filling fuel gas, a gas-fueled vehicle, on
which a gas tank is mounted, such as a fuel cell vehicle, pulls
into a gas station and the gas tank is filled with the fuel gas
from a filling nozzle of a gas filling apparatus. It is known that
when the fuel gas is hydrogen gas, the temperature increases as the
fuel gas is filled. A hydrogen gas filling apparatus described in
Japanese Patent Application Publication No. 2005-83567
(JP-A-2005-83567) is provided with a cooling means (a so-called
precooler) to precool the hydrogen gas by heat exchange with a
coolant and the cooled hydrogen gas is filled into the gas tank, so
that the time for filling up is reduced. In the hydrogen gas
filling apparatus, in order to prevent the occurrence of
condensation when the hydrogen gas is over-cooled, the supply
pressure of the hydrogen gas is detected and the flow rate and the
temperature of the coolant supplied to the cooling means is
controlled based on the results of detection.
[0005] However, when a plurality of fuel cell vehicles are
consecutively filled up, for example, there is a possibility that
the flow rate etc. of the coolant supplied to the cooling means is
not appropriately controlled and the temperature of the coolant in
the cooling means exceeds a predetermined temperature. When as a
result the hydrogen gas that has not been appropriately cooled is
filled into the gas tank, there is a fear that the temperature in
the gas tank increases and reaches the design temperature
(85.degree. C., for example) before the completion of filling up.
On the other hand, when the filling is stopped because of the
insufficient cooling, there is a fear of making the driver
wait.
SUMMARY OF THE INVENTION
[0006] The invention provides a gas filling system and a gas
filling apparatus capable of optimizing the filling of a gas tank
with gas via a gas filling apparatus equipped with a cooling
device.
[0007] A gas filling system according to the invention includes: a
gas tank; a gas filling apparatus, including a cooling device for
cooling gas supplied from a gas supply source, that discharges the
gas cooled by the cooling device to fill the gas into the gas tank;
a gas temperature sensor that detects, upstream of the gas tank, a
temperature of the gas cooled by the cooling device; and a flow
rate controller that controls a filling flow rate of the gas to be
filled into the gas tank, based on the temperature of the gas
detected by the gas temperature sensor.
[0008] A gas filling apparatus according to the invention includes
a cooling device for cooling gas supplied from a gas supply source
and discharges the gas cooled by the cooling device to fill the gas
into the gas tank. The gas filling apparatus is characterized by
further including: a gas temperature sensor that detects, upstream
of the gas tank, a temperature of the gas cooled by the cooling
device; and a flow rate controller that controls a filling flow
rate of the gas to be filled into the gas tank, based on the
temperature of the gas detected by the gas temperature sensor.
[0009] According to the invention, the filling flow rate is varied
based on the temperature of the gas cooled by the cooling device,
so that it is possible to perform optimum filling according to the
cooling power of the cooling device. Thus, it is possible to fill a
predetermined filling amount of gas (both in the case of the
filling amount for a full tank and in the case of the filling
amount for a specified filling level) into the gas tank in a
minimum period of time while maintaining the inside of the gas tank
stable.
[0010] The flow rate controller may control the filling flow rate
so that the filling flow rate is reduced as the temperature of the
gas increases. Thus, it is made possible to complete filling a
predetermined filling amount of gas in a short period of time while
preventing the temperature in the gas tank from reaching the design
temperature when the temperature of the gas is high because of the
consecutive filling, for example. On the other hand, when the
temperature of the gas is low, it is possible to complete filling a
predetermined amount of gas in a shorter period of time than in the
case of a higher gas temperature.
[0011] The gas filling system may further include a gas tank sensor
that acquires information concerning the inside of the gas tank and
the flow rate controller may control the filling flow rate based
also on the information acquired by the gas tank sensor. With this
configuration, it is possible to perform filling according to the
state in the gas tank that is the subject to be filled. In
addition, because the information in the gas tank is acquired, it
is possible to perform control of the filling flow rate with higher
accuracy as compared to the case where such information is
estimated.
[0012] The gas tank sensor may include at least one of a gas tank
temperature sensor and a gas tank pressure sensor. With this
configuration, when it is detected that the temperature in the gas
tank is high, for example, it is possible to suppress further
increase in the temperature in the gas tank by reducing the filling
flow rate.
[0013] The gas filling system may include a plurality of the gas
tanks, the gas tank sensor may acquire the information for each of
the gas tanks, and the flow rate controller may control the filling
flow rate based on the information on the gas tank, in which a
temperature is the highest, or on the information on the gas tank,
in which a pressure is the lowest, among pieces of the information
acquired by the gas tank sensors. With this configuration, it is
possible to complete filling a predetermined filling amount of gas
in a short period of time while preventing the temperature of all
the gas tanks from reaching the design temperature.
[0014] The gas temperature sensor may detect the temperature of the
gas in the cooling device. With this configuration, it is possible
to optimize the filling based on the temperature of the gas in the
cooling device.
[0015] The gas temperature sensor may detect the temperature of the
gas after being discharged from the gas filling apparatus into the
gas tank. With this configuration, it becomes unnecessary to take
account of the influence of the disturbance in the gas filling
apparatus with regard to the detected value of the temperature of
the gas that has been cooled. In other words, it is possible to
detect the temperature of the gas immediately before being filled
that most affects the state in the gas tank and therefore, it is
possible to control the filling flow rate with high accuracy.
[0016] The gas filling system may further include a connection unit
for connecting the gas tank and the gas filling apparatus at the
time of filling and the gas temperature sensor may detect the
temperature of the gas at the connection unit. With this
configuration, similarly to the above case, it is possible to
minimize the influence of the disturbance on the detected value of
the temperature of the gas that has been cooled. In addition, it is
possible to increase the applicability, that is, for example, it is
possible to utilize the connection unit to install the gas
temperature sensor.
[0017] The connection unit may include a receptacle on the gas tank
side and a filling nozzle on the gas filling apparatus side that is
connected to the receptacle, and the gas temperature sensor may
detect the temperature of the gas at the filling nozzle or at the
receptacle.
[0018] The gas filling system of the invention may further include
a display device that displays an indication that the filling flow
rate is being controlled based on the temperature of the gas
detected by the gas temperature sensor or an indication that the
filling flow rate has been controlled based on the temperature of
the gas detected by the gas temperature sensor. In this case, the
display device may be provided in the gas filling apparatus or in a
mobile body, on which the gas tank is mounted. With this
configuration, it is possible to visually confirm that optimum
filling according to the cooling power of the cooling device is
being performed or has been performed in the gas filling apparatus
or in the mobile body.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] The foregoing and further objects, features and advantages
of the invention will become apparent from the following
description of example embodiments with reference to the
accompanying drawings, wherein like numerals are used to represent
like elements and wherein:
[0020] FIG. 1 is a schematic diagram of a gas filling system
according to an embodiment;
[0021] FIG. 2 is a configuration diagram of the gas filling system
according to the embodiment;
[0022] FIG. 3 is a flow chart showing a flow of a filling operation
in the gas filling system according to the embodiment; and
[0023] FIG. 4 is a diagram showing an example of a filling flow
rate map used in the filling operation according to the
embodiment.
DETAILED DESCRIPTION OF EMBODIMENTS
[0024] A gas filling system according to an example embodiment of
the invention will be described below with reference to the
attached drawings. An example of the gas filling system will be
herein described, in which hydrogen gas is filled, via a gas
filling apparatus, into a gas tank of a fuel cell vehicle equipped
with a fuel cell system. As generally known, the fuel cell system
includes a fuel cell that generates electricity through
electrochemical reaction between fuel gas (hydrogen gas, for
example) and oxidant gas (air, for example).
[0025] As shown in FIG. 1, the gas filling system 1 includes the
gas filling apparatus 2 that is provided in a hydrogen station, for
example, and a vehicle 3 supplied with the hydrogen gas from the
gas filling apparatus 2.
[0026] As shown in FIG. 2, the gas filling apparatus 2 has
clustered cylinders (gas supply source) 11 that store hydrogen gas,
a filling nozzle 12 that discharges hydrogen gas into an on-board
gas tank 30, and a gas line 13 that connects the clustered
cylinders 11 and the filling nozzle 12. The filling nozzle 12,
which is a part also referred to as a filling coupling, is
connected to a receptacle 32 of the vehicle 3 when the hydrogen gas
is filled. The filling nozzle 12 and the receptacle 32 constitute a
connection unit that connects the gas filling apparatus 2 and the
gas tank 30.
[0027] The gas line 13 is provided with: a compressor 14 that
pressurizes and discharges the hydrogen gas supplied from the
clustered cylinders 11; an accumulator 15 that stores the hydrogen
gas that has been pressurized to a predetermined pressure by the
compressor 14; a flow rate control valve 16 that controls the flow
rate of the hydrogen gas supplied from the accumulator 15; a flow
meter 17 that measures the flow rate of the hydrogen gas; a
precooler 18 that precools the hydrogen gas flowing through the gas
line 13; and a temperature sensor T that detects the temperature of
the hydrogen gas downstream of the precooler 18, in this order from
the clustered cylinders 11 side. The gas filling apparatus 2
includes a communication device 21, a display device 22, an ambient
temperature sensor 23, and a controller 24. Various devices are
electrically connected to the controller 24. Although not
illustrated, a cutoff valve that opens the gas line 13 during
filling is provided in or downstream of the accumulator 15.
[0028] The flow rate control valve 16 is an electrically driven
valve and includes a stepping motor, for example, as the driving
power source. The degree of opening of the flow rate control valve
16 is changed by the stepping motor according to the command from
the controller 24, so that the flow rate of the hydrogen gas is
controlled. In this way, the filling flow rate, at which the
hydrogen gas is filled into the gas tank 30, is controlled. The
thus-controlled filling flow rate is measured by the flow meter 17
and the controller 24 receives the measurement result and
feedback-controls the flow rate control valve 16 so as to achieve a
desired filling flow rate. It is also possible to use another flow
rate controller than the flow rate control valve 16.
[0029] The precooler 18 cools the hydrogen gas that is supplied
from the accumulator 15 at approximately room temperature, to a
predetermined low temperature (-20.degree. C., for example) by heat
exchange. The type of the heat exchange in the precooler 18 may be
any of the indirect type, the intermediate medium type, and the
regenerative type and one of the publicly known structures may be
used. For example, the precooler 18 has a pipeline portion, through
which the hydrogen gas flows, and in the precooler 18, the pipeline
portion is housed in a container, in which coolant flows, so that
heat is exchanged between the hydrogen gas and the coolant. In this
case, the cooling temperature of the hydrogen gas may be controlled
by controlling the amount and the temperature of the coolant
supplied to the container. In this way, the temperature of the
hydrogen gas cooled by the precooler 18 is detected by the
temperature sensor T and the signal indicative of the detection
result is supplied to the controller 24.
[0030] The communication device 21 has a communication interface
for performing wireless communication, such as infrared data
communication, for example. The display device 22 displays various
pieces of information, such as information on the filling flow rate
during filling, on a screen. The display device 22 may be equipped
with an operation panel for selecting or specifying the desired
filling amount on the display screen.
[0031] The controller 24 is made up of a microcomputer including a
central processing unit (CPU), a read only memory (ROM), and a
random access memory (RAM) therein. The CPU performs desired
calculations according to the control program to perform various
processes and control operations. The ROM stores the control
program executed by the CPU and control data. The RAM is mainly
used as various workspaces for performing control processes. The
controller 24 is electrically connected to the clustered cylinders
11, the compressor 14, the accumulator 15, and the precooler 18, in
addition to the communication device 21 etc. that are connected to
the controller 24 via control lines expressed by chain lines in
FIG. 2 and controls the whole of the gas filling apparatus 2. In
addition, the controller 24 transmits the information obtainable in
the gas filling apparatus 2 to the vehicle 3 via the communication
device 21.
[0032] The vehicle 3 includes the gas tank 30 and the receptacle
32. The gas tank 30 is a fuel gas supply source for supplying fuel
to the fuel cell. The gas tank 30 is a high-pressure tank capable
of storing hydrogen gas at 35 MPa or 70 MPa, for example. The
hydrogen gas in the gas tank 30 is supplied to the fuel cell via
the supply pipeline (not shown). The supply of hydrogen gas to the
gas tank 30 is performed by the gas filling apparatus 2 via the
receptacle 32 and a filling pipeline 34. The filling pipeline 34 is
provided with a check valve 36 for preventing the hydrogen gas from
flowing backward, for example. A temperature sensor 40 and a
pressure sensor 42 detect the temperature and the pressure,
respectively, of the hydrogen gas in the gas tank 30 and are
provided in the supply pipeline or the filling pipeline 34.
[0033] The vehicle 3 includes: a communication device 44 that
transmits and receives various pieces of information to and from
the communication device 21 of the gas filling apparatus 2; a
controller 46 made up of a microcomputer similarly to the
controller 24 of the gas filling apparatus 2; and a display device
48 that displays various pieces of information on a screen. The
communication device 44 is compatible with the communication device
21 and the communication device 44 has a communication interface
for performing wireless communication, such as infrared data
communication, for example. The communication device 44 is
incorporated into the receptacle 32 or is fixed in a lid box of the
vehicle 3 so that it is possible to establish communication between
the communication devices 44 and 21 in a state where the filling
nozzle 12 is connected to the receptacle 32. The controller 46
receives the results of detection from various sensors including
the temperature sensor 40 and the pressure sensor 42 and controls
the vehicle 3. The controller 46 transmits the information
obtainable in the vehicle 3 to the gas filling apparatus 2 via the
communication device 44. The display device 48 can be used as part
of the car navigation system, for example.
[0034] In the above-described gas filling system 1, when hydrogen
gas is filled into the gas tank 30 of the vehicle 3, first, the
filling nozzle 12 is connected to the receptacle 32. Then, the gas
filling apparatus 2 is activated. Upon the activation, the hydrogen
gas stored in the accumulator 15 is cooled by the precooler 18 and
then, the hydrogen gas is discharged from the filling nozzle 12 to
the gas tank 30, whereby the hydrogen gas is filled into the gas
tank 30. The gas filling system 1 of the present embodiment
controls the filling flow rate according to the temperature of the
cooled hydrogen gas.
[0035] Next, with reference to the flow chart of FIG. 3, the
control of the filling flow rate in the gas filling system 1 will
be described.
[0036] First, the filling operator connects the filling nozzle 12
to the receptacle 32 and when the filling starting operation is
performed, by which the discharge of hydrogen gas from the gas
filling apparatus 2 into the gas tank 30 is allowed, filling is
started (step S1). Thus, the hydrogen gas stored in the accumulator
15 is cooled in the precooler 18 and then discharged into the gas
tank 30.
[0037] Immediately after starting filling, the tank pressure, the
tank temperature, and the precooler temperature are read in. The
tank pressure is the pressure of the hydrogen gas in the gas tank
30 and is detected by the pressure sensor 42. The tank temperature
is the temperature of the hydrogen gas in the gas tank 30 and is
detected by the temperature sensor 40. The signals indicative of
the results of detection of the tank pressure and the tank
temperature are supplied to the controller 46. The controller 46
transmits the detected values of the tank pressure and the tank
temperature to the gas filling apparatus 2 with the use of the
communication device 44. The controller 24 of the gas filling
apparatus 2 thus obtains the tank pressure and the tank temperature
immediately after starting filling. The precooler temperature is
the temperature of the hydrogen gas in the precooler 18 and is
detected by the temperature sensor T. The controller 24 that
directly receives the signal indicative of the result of detection
of the precooler temperature obtains the precooler temperature
immediately after starting filling.
[0038] After receiving these three pieces of information, the
controller 24 determines the filling flow rate based on a filling
flow rate map stored in the ROM or the like (step S2). The filling
flow rate map Ma, examples of which are shown in FIG. 4, is a map,
in which the vertical axis indicates the tank pressure and the
horizontal axis indicates the tank temperature. The filling flow
rate map Ma is set for each of a plurality of precooler
temperatures (T.sub.1, T.sub.2, T.sub.3, which satisfy the
relation, T.sub.1<T.sub.2<T.sub.3, for example). When the
detected precooler temperature is T.sub.1, the tank pressure is 40
MPa, and the tank temperature is 0.degree. C., for example, the
controller 24 selects D4 (m.sup.3/min) as the filling flow rate,
for example.
[0039] The filling flow rate in the filling flow rate map Ma is a
flow rate that enables the hydrogen gas to be filled into the gas
tank 30 smoothly at a high speed under given conditions of the tank
pressure, the tank temperature, and the precooler temperature. More
specifically, each of the filling flow rates in the filling flow
rate map Ma is the flow rate that enables a maximum amount of
hydrogen gas (the filling amount for a full tank, for example) to
be filled in a minimum period of time while the temperature in the
gas tank 30 is prevented from reaching a predetermined upper limit
value (85.degree. C., for example). In the filling flow rate map
Ma, the tank pressure is set at intervals of 10 MPa and the tank
temperature is set at intervals of 10.degree. C. However, these
intervals may be arbitrarily set. Also the precooler temperature
may be arbitrarily set at intervals of 2 to 3.degree. C., 5.degree.
C., or 10.degree. C., for example.
[0040] Two points concerning the order of the values of the filling
flow rate in the filling flow rate map Ma will now be described.
First, when the conditions of the tank pressure and the tank
temperature are the same, the higher the precooler temperature is,
the lower the value of the filling flow rate is. When the tank
pressure is 40 MPa and the tank temperature is 0.degree. C., for
example, the filling flow rate at the precooler temperature T.sub.2
is lower than the filling flow rate D4 at the precooler temperature
T.sub.1. When such a reduced filling flow rate is used, it is
possible to complete filling in a minimum period of time while the
temperature in the gas tank 30 is prevented from reaching an upper
limit value even when the precooler temperature is increasing
because of the consecutive filling.
[0041] Second, when the precooler temperature is the same, the
filling flow rate may be increased as the tank pressure increases.
In this case, the filling flow rate may be increased as the tank
temperature decreases. For example, when the precooler temperature
is T.sub.1, among the filling flow rates A1 to H8 in the filling
flow rate map Ma, the filling flow rate H1 (tank pressure: 80 MPa
and tank temperature: -30.degree. C.) is the highest and the
filling flow rate A8 (tank pressure: 10 MPa and tank temperature:
40.degree. C.) is the lowest. When a reduced filling flow rate is
used in the case of a low tank pressure or a high tank temperature
in this way, it is possible to complete filling in a minimum period
of time while the temperature in the gas tank 30 is prevented from
reaching an upper limit value.
[0042] In step S3, the controller 24 controls the gas filling
apparatus 2 so that the filling flow rate is brought to the value
that is determined in step S2. Specifically, while monitoring the
result of measurement by the flow meter 17, the controller 24
controls the degree of opening of the flow rate control valve 16 so
that the filling flow rate is brought to the determined value. In
this way, hydrogen gas is filled into the gas tank 30 at a filling
flow rate according to the given conditions of the tank pressure,
the tank temperature, and the precooler temperature.
[0043] During the filling, at least one of the display device 22 of
the gas filling apparatus 2 and the display device 48 of the
vehicle 3 indicates that the filling is being performed at the
filling flow rate determined in step S2. In other words, the
filling operator can confirm that the filling flow rate is being
controlled based on the conditions including the precooler
temperature, by the indication on at least one of the display
devices 22 and 48 of the gas filling system 1.
[0044] Thereafter, when a predetermined filling amount of gas (the
amount of gas to be filled that is specified by the filling
operator or the filling amount for a full tank) has been filled
into the gas tank 30, the supply of hydrogen gas from the gas
filling apparatus 2 is stopped and the filling is ended (step S4).
Also after the completion of the filling or only after the
completion of the filling, the indication similar to the above
indication, that is, the indication that the filling flow rate has
been controlled based on the conditions including the precooler
temperature, for example, may be given on at least one of the
display devices 22 and 48.
[0045] According to the gas filling system 1 according to this
embodiment described above, it is possible to fill hydrogen gas
into the gas tank 30 at a flow rate according to the tank pressure,
the tank temperature, and the precooler temperature. In particular,
although there is a case where the hydrogen gas temperature after
cooling varies depending on the power of the precooler, according
to this embodiment, it is possible to detect the precooler
temperature and control the filling flow rate according to the
detected precooler temperature. Thus, it is made possible to
perform optimum filling according to the cooling power of the
precooler 18 and it is therefore possible to fill a predetermined
filling amount of gas into the gas tank 30 in a minimum period of
time while maintaining the inside of the gas tank 30 stable.
[0046] As described above, for example, when control is performed
so that the filling flow rate is reduced as the precooler
temperature increases, it is possible to ensure a smooth,
high-speed filling while the temperature of the inside of the gas
tank 30 is prevented from exceeding an upper limit temperature. In
other words, this effect can be said as follows: even when the
cooling to a certain level is not performed by the precooler 18
yet, there is no need to interrupt or stop the filling operation
and there is no need to make the filling operator or the driver
wait. In addition, it is possible to fill up a plurality of
vehicles 3 consecutively. On the other hand, when the precooler
temperature is relatively low, by setting the filling flow rate
relatively higher, it is possible to perform a smooth filling in a
shorter period of time while the temperature of the inside of the
gas tank 30 is prevented from exceeding an upper limit
temperature.
[0047] In addition, because the information concerning the inside
of the gas tank 30, that is, the tank pressure and the tank
temperature, is actually acquired in order to determine the filling
flow rate, it is possible to determine the more optimal filling
flow rate as compared to the case where these values are estimated.
In an alternative embodiment, control may be performed after
determining the filling flow rate according to the precooler
temperature without taking one of or both of the tank pressure and
the tank temperature into consideration.
<Modifications>
[0048] Next, some modifications of the gas filling system 1 of the
embodiment will be described. Each modification can be applied to
the embodiment either alone or in combination with another
modification.
[0049] In a first modification, the tank pressure and the tank
temperature may be estimated when the filling flow rate is
determined. In this case, the tank pressure and the tank
temperature can be estimated with the use of the device(s) on the
gas filling apparatus 2 side. For example, with regard to the tank
pressure, a pressure sensor may be provided in the gas line 13 of
the gas filling apparatus 2 and the tank pressure may be estimated
based on the result of detection by the pressure sensor immediately
after starting filling. On the other hand, the tank temperature may
be estimated based on the result of detection by the ambient
temperature sensor 23 immediately after starting filling. Such a
method using the estimation is useful in the case where neither the
gas filling apparatus 2 nor the vehicle 3 is provided with the
communication means (the communication devices 21 and 44 described
above).
[0050] In a second modification, the position of the temperature
sensor T that detects the precooler temperature may be changed. In
order to optimize the filing flow rate according to the temperature
of the hydrogen gas after being cooled by passing through the
precooler 18, it suffices that the temperature sensor T detects the
temperature of the hydrogen gas between the precooler 18 and a
point upstream the gas tank 30. Thus, the temperature sensor T may
be provided in the receptacle 32 or the filling pipeline 34 on the
vehicle 3 side. Alternatively, the temperature sensor T may detect
the temperature of the hydrogen gas after being discharged from the
gas filling apparatus 2 toward the gas tank 30. In another
embodiment, the temperature sensor T may be provided in the filling
nozzle 12 and may detect the temperature of the hydrogen gas at the
filling nozzle 12.
[0051] When the detection by the temperature sensor T is performed
at such a position, there is no need to consider the influence of
the disturbance within the gas filling apparatus 2 on the detection
value of the temperature of the cooled hydrogen gas. In other
words, when the distance between the precooler 18 and the filling
nozzle 12 is large, at the filling nozzle 12, the temperature of
the hydrogen gas that has been cooled in the precooler 18 can
exceed the temperature immediately downstream of the precooler 18
because of reception of heat in the piping of the gas line 13.
However, when the hydrogen gas temperature is detected at a
position downstream of the filling nozzle 12, such an influence can
be avoided and it is possible to detect the temperature of the
hydrogen gas immediately before being filled that influences the
state of the inside of the gas tank 30 most. Thus, it is possible
to control the filling flow rate more accurately.
[0052] In a third modification, the number of gas tanks 30 may be
plural. When a plurality of gas tanks are mounted on the vehicle 3,
the heat radiation varies depending on the mounting position and
the amount of discharge from individual gas tanks varies depending
on the manner in which the gas is supplied to the fuel cell. Thus,
when there are a plurality of gas tanks 30, the filling flow rate
may be determined from the filling flow rate map Ma based on the
precooler temperature and the information (tank temperature and
tank pressure) on the gas tank whose temperature is the highest or
the gas tank whose pressure is the lowest among the plurality of
gas tanks. In this way, it is possible to complete filling a
predetermined filling amount of gas in a short period of time while
preventing the temperature from reaching the upper limit
temperature for every gas tank.
[0053] In the case of the third modification, the tank temperature
and the tank pressure of each of the gas tanks may be acquired by
providing each of the gas tanks with the temperature sensor 40 and
the pressure sensor 42 or may be acquired with the use of one
temperature sensor 40 and one pressure sensor 42 in total for all
of the gas tanks. Alternatively, as described in connection with
the second modification, the tank temperature and the tank pressure
may be acquired by estimation for each of the gas tanks.
[0054] The gas filling system 1 according to the invention may be
used not only in the case of hydrogen gas but also in the case of a
gas whose temperature increases during filling. In addition, the
gas filling system 1 can be applied not only to the vehicle 3, but
also to a mobile body, such as an air plane, a ship, or a robot, on
which a gas tank to be filled with gas supplied from the outside is
mounted.
[0055] The invention has been described with reference to example
embodiments for illustrative purposes only. It should be understood
that the description is not intended to be exhaustive or to limit
form of the invention and that the invention may be adapted for use
in other systems and applications. The scope of the invention
embraces various modifications and equivalent arrangements that may
be conceived by one skilled in the art.
* * * * *