JP2003308865A - Vehicle fuel gas supply device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicle fuel gas supply device allowing more reliable diagnosis of shut-off valves arranged at the outlet of a fuel tank. <P>SOLUTION: The vehicle fuel gas supply device comprises fuel gas consumption estimating means 11 for estimating the amount of fuel gas consumed by a fuel cell 1, shut-off valve control means 10 for determining the opened/closed condition of the shut-off valves, fuel gas supply estimating means 12 for estimating the amount of the fuel gas supplied from a fuel supply source from the pressure change rate of the fuel gas, the temperature of the fuel gas, the volume of a gas supply passage and the volume of the fuel supply source being instructed to be opened, and shut-off valve condition determining means 13 for comparing two fuel gas consumption estimated values with each other and determining whether the shut-off valves 3A, 3B are normal or not. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle fuel gas supply apparatus suitable for determining a failure state of a shutoff valve arranged at a fuel tank outlet.

[0002]

2. Description of the Related Art Conventionally, there has been known one in which a failure state of a shut-off valve is determined by opening / closing the shut-off valve to determine a failure state of the shut-off valve from a change in gas pressure in the downstream side.
There are those disclosed in Japanese Patent No. 74311, Japanese Patent Laid-Open No. 2000-303909, Japanese Patent Laid-Open No. 9-22711, and the like.

Among the above-mentioned conventional techniques, for example, Japanese Patent Laid-Open No. 2000-2000
In Japanese Patent Publication No. 274311, a shutoff valve and a pressure sensor are arranged in this order in a pipe that supplies gas fuel to a gas engine, and the shutoff valve is closed based on a failure diagnosis signal while the vehicle is stopped or in operation. Thereafter, the pressure decrease rate is calculated based on the pressure information and the elapsed time taken from the pressure sensor, and when the calculated pressure decrease rate is smaller than a predetermined pressure decrease rate threshold value, the shutoff valve operates. It is determined to be in a failure state. In this case, it can be determined whether the shutoff valve remains open and cannot be closed, or the shutoff valve is locked on the open side and sufficient shutoff cannot be obtained.

[0004]

By the way, when the conventional technique is applied to a fuel cell vehicle using hydrogen gas as a fuel,
The fuel gas flows into the pipe through the cutoff valve and flows out from the pipe in response to the consumption by the fuel cell.

However, in the above prior art,
Since only the pressure change rate of the pipe is measured, fuel gas consumption by the fuel cell is not taken into consideration. Therefore,
It is difficult to determine whether the cause of the pressure change is the failure of the shutoff valve or the consumption of the fuel cell. That is, the failure of the shutoff valve cannot be accurately determined.

Therefore, the present invention has been made in view of the above problems, and an object thereof is to provide a fuel gas supply system for a vehicle, which enables more reliable diagnosis of a shutoff valve arranged at the outlet of a fuel tank. To do.

[0007]

A first aspect of the present invention is a fuel gas supply for a vehicle in which a shutoff valve, a pressure sensor and a temperature sensor are arranged in a gas supply path for supplying a fuel gas from a fuel gas supply source to a fuel cell. In the apparatus, a fuel gas consumption estimating means for estimating the amount of fuel gas consumed by the fuel cell, a shutoff valve control means for determining the open / closed state of the shutoff valve, a fuel gas pressure change amount, a fuel gas temperature, and a gas supply. Fuel gas supply amount estimating means for estimating the amount of fuel gas supplied from the fuel supply source from the path volume and the volume of the fuel supply source for which the open command is issued, the fuel gas supply amount estimated value, and the fuel gas consumption And a shutoff valve state determination means for determining whether the shutoff valve is normal or defective by comparing the quantity estimated values. The fuel gas consumption estimation means may measure the amount of fuel gas flowing into the fuel cell with a flow meter or the like, or may measure the output current or generated power of the fuel cell to estimate the amount of fuel gas. Good.

In a second aspect based on the first aspect, the fuel gas supply source comprises a plurality of fuel gas tanks,
The gas supply path comprises a shutoff valve installed at a supply port of each of the fuel gas tanks, and a gas feed pipe that joins the downstream of each shutoff valve and communicates with a fuel cell. .

A third invention is characterized in that, in the second invention, the plurality of fuel gas tanks are constituted by fuel gas tanks having different volumes.

In a fourth aspect based on the first to third aspects, the fuel gas consumption estimating means has a fuel cell operating state detecting means for detecting an operating state of the fuel cell, and based on the detection result. It is characterized by estimating the fuel gas consumption.

A fifth invention is characterized in that, in the fourth invention, the fuel cell operating state detecting means is a fuel cell output current detecting means for detecting an output current of the fuel cell.

[0012]

Therefore, in the first aspect of the invention, the fuel gas consumption estimating means for estimating the amount of fuel gas consumed in the fuel cell main body, the fuel gas pressure change amount, the fuel gas temperature, the gas supply path volume, and the opening amount are set. The shutoff valve is normal by comparing the estimated fuel gas amount with the fuel gas supply amount estimation means that estimates the amount of fuel gas supplied from the fuel supply source from the volume of the fuel supply source for which the command has been issued. In order to determine whether or not there is a failure, the open / closed state of the shutoff valve can be accurately detected, and by comparing with the command of the shutoff valve control means, a more reliable diagnosis of the shutoff valve failure state becomes possible.

In the second invention, in addition to the effect of the first invention, the fuel gas supply amount estimating means is located downstream of the shutoff valve and has a fuel gas pressure change amount, a fuel gas temperature, a gas supply path volume, and an opening command. In order to estimate the amount of fuel gas supplied from the fuel supply source from the volume of the fuel supply source that is being output, even if a plurality of fuel tanks are arranged, without adding sensors etc. The shutoff valve can be reliably diagnosed.

In the third invention, in addition to the effect of the second invention, since the plurality of fuel gas tanks are composed of fuel gas tanks having different volumes, a plurality of shutoff valves are provided, but the shutoff valves are opened and closed a small number of times. It is possible to diagnose by.

In the fourth invention, in addition to the effects of the first to third inventions, the fuel gas consumption estimating means has a fuel cell operating state detecting means for detecting the operating state of the fuel cell,
Since the fuel gas consumption is estimated based on the detection result, the present diagnosis can be applied as long as it has a sensor for detecting the state of the fuel cell.

In the fifth invention, in addition to the effect of the fourth invention, the fuel cell operating state detecting means is the fuel cell output current detecting means for detecting the output current of the fuel cell, and therefore is attached to the fuel cell. The present invention can be easily applied by an ammeter.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an embodiment for realizing a vehicle fuel gas supply system according to the present invention will be described in claims 1, 2,
A description will be given based on the first embodiment corresponding to Nos. 4 and 5.

(First Embodiment) FIGS. 1 to 3 show a first embodiment of the present invention. FIG. 1 is a system configuration diagram of a fuel gas supply system for a vehicle, and FIGS. FIG. 3 is a time chart showing the operating state of the shutoff valve in the failure diagnosis.

In FIG. 1, the vehicle fuel gas supply device is a system mounted on a moving body such as a fuel cell vehicle, and includes fuel tanks 2A and 2B and fuel tanks 2A and 2B.
From the fuel cell 1 that receives the supply of the fuel gas and the oxidant gas from the fuel cell 1 to generate electricity by the electrochemical reaction, and the controller 7 that performs the control for the purpose of safely and efficiently operating the fuel cell 1. It is configured. The fuel tank 2
A and 2B store hydrogen as a fuel gas. The two fuel tanks 2A and 2B having the same volume are connected to the high-pressure pipe 4 via cut-off valves 3A and 3B having a backflow prevention function, respectively, and the fuel cell 1 is connected via the cut-off valves 3A and 3B and the high-pressure pipe 4. It is possible to supply fuel gas to.

A pressure sensor 5 for measuring the pressure of the fuel gas in the high-pressure pipe 4 and a temperature sensor 6 for measuring the temperature of the fuel gas in the high-pressure pipe 4 are arranged in the high-pressure pipe 4.

The controller 7 includes a shutoff valve control means 10
And a fuel gas consumption estimation means 11, a fuel gas supply amount estimation means 12, and a shutoff valve state determination means 13.

The shutoff valve control means 10 includes shutoff valves 3A and 3B.
The open / close command is output to.

The fuel gas consumption estimating means 11 estimates the amount of fuel gas consumed in the fuel cell 1.

The fuel gas supply amount estimating means 12 includes the fuel gas pressure measured by the pressure sensor 5, the fuel gas temperature measured by the temperature sensor 6, the volume of the high pressure pipe 4 measured in advance, and the shutoff valve. The amount of fuel gas supplied is estimated from the volume of the fuel tank 2A or 2B for which the control unit 10 has issued an open command.

The shutoff valve state determination means 13 compares the fuel consumption amount in the fuel cell 1 estimated by the fuel gas consumption amount estimation means 11 with the fuel supply amount estimated by the fuel gas supply amount estimation means 12, and calculates in advance. According to the determined logic, it is determined whether the cutoff valves 3A and 3B are in a normal state or a failure state.

Next, the detailed procedure of this diagnosis will be described with reference to the flowchart of FIG. In the flowchart, the operation of the fuel gas consumption amount estimating means 11 is step 17
0 to 240 and steps 400 to 450, the operation of the fuel gas supply amount estimating means 12 is performed at steps 130 to 150 and steps 370 to 390, and the shutoff valve state determining means 1 is performed.
The operation of 3 is performed in steps 250 to 290 and step 330.
360 and steps 460-510 respectively apply. Further, the shut-off valves 3A and 3B may fail while remaining closed or may fail while remaining open. Two shutoff valves 3
A, 3B and the fuel tanks 2A, 2B are provided, so that the fuel gas supplied to the fuel cell 1 does not depend on which shutoff valve 3
When A and 3B are also closed and only the fuel gas in the high-pressure pipe 4 is used, either one (the other) shutoff valve 3A or 3B is opened and the other (one) is closed and the one (the other) fuel tank 2 is closed.
In the case of A or 2B and the fuel gas in the high-pressure pipe 4, both shutoff valves 3A, 3B are opened and both fuel tanks 2A,
2B and the fuel gas in the high-pressure pipe 4 in some cases.

First, at step 100, it is judged whether or not a start signal is issued to the fuel cell 1. If the activation signal is not issued, wait until the activation signal is issued. When the activation signal is issued, the process proceeds to step 110.

In step 110, the shutoff valve control means 10
Outputs an opening command to the shutoff valve 3A.

In step 120, it is determined whether or not a predetermined time has elapsed since the "open" command was issued to the shutoff valve 3A. The predetermined time here is
The time from when the shutoff valve 3A is opened until the pressure in the high-pressure pipe 4 becomes substantially equal to the pressure in the fuel tank 2A is measured,
Set a value that is approximately equal to or greater than that time. After the elapse of the predetermined time, the process proceeds to step 130.

In step 130, the fuel gas pressure in the high pressure pipe 4 is measured by the pressure sensor 5, and the value is set to P1.

In step 140, the temperature of the fuel gas is measured by the temperature sensor 6, and the value is set as T1.

In step 150, when the shutoff valve 3A is normally opened and the shutoff valve 3B is closed, the estimated hydrogen supply amount when the pressure in the high-pressure pipe 4 is consumed by the fuel cell 1 and decreases by ΔP. M1 is calculated using the following equation of state: n1 = (P1 (V1 + Vpipe)) / R · T n2 = (P2 (V1 + Vpipe)) / R · T M1 = n1-n2 However, P2 = P1−ΔP, T is T
1 is an absolute temperature, R is a gas constant, V1 is the volume of the fuel tank, and Vpipe is the volume of the high-pressure pipe.

In step 160, the fuel cell 1 is actually started and the consumption of fuel from the high pressure pipe 4 is started.

In step 170, the estimated hydrogen consumption M2
The initial value of is set to zero.

In step 190, the output current I of the fuel cell 1 is measured by a current sensor (not shown).

In step 210, from the output current I, the Faraday constant F, the control cycle Ts, and the cell stack number n, it is assumed that the state of the fuel cell 1 does not change during one control cycle. Therefore, δM = (I · Ts) · n / (2 · F) 1 The amount of hydrogen δM consumed in the fuel cell 1 during one control cycle
(Mol) is calculated.

In step 220, the hydrogen amount δM calculated in step 210 is added to the estimated hydrogen consumption amount M2 as shown in the following formula, and M2 = M2 + δM The total hydrogen consumption amount M from the start of operation of the fuel cell 1 is calculated.
Set to 2.

In step 230, the fuel gas pressure in the high-pressure pipe 4 is measured again by the pressure sensor 5, and the value is P2.
And

In step 240, the fuel gas pressures P1 and P
The difference from 2 is calculated, and it is determined whether the pressure in the high-pressure pipe 4 has decreased by a predetermined differential pressure ΔP due to fuel consumption of the fuel cell 1. If not, step 190
Returning to, the hydrogen amount δM consumed in the next control cycle is calculated to obtain the estimated hydrogen consumption amount M2. If the pressure difference ΔP has decreased, the process proceeds to step 250.

At step 250, the estimated hydrogen supply amount Ml calculated from the equation of state at step 150 and the estimated hydrogen consumption amount M2 obtained from the output current I of the fuel cell 1 at step 220 are compared, and the difference is found. It is checked whether the value is equal to or less than a predetermined value ΔM. The predetermined value ΔM is set in advance in consideration of the measurement error of the current sensor, the temperature sensor 6, the pressure sensor 5 and the like, and may be regarded as substantially the same value. If the difference is less than or equal to the predetermined value ΔM, that is, if it is determined that the values are substantially equal, the process proceeds to step 300. If the difference is larger than the predetermined value ΔM and it is judged that they cannot be considered equal, the process proceeds to step 260.

In step 260, the estimated hydrogen supply amount M1
Which is larger than the estimated hydrogen consumption M2 is determined.
If the estimated hydrogen supply amount M1 is larger, step 270
If the estimated hydrogen consumption M2 is larger, go to step 29.
Go to 0.

In step 270, the estimated hydrogen supply amount M1
Is larger, that is, it is determined that the hydrogen consumption amount M2 actually consumed in the fuel cell 1 is smaller than the hydrogen consumption amount M1 when the cutoff valve 3A is operating normally. Since the valve 3A was not opened and the fuel was supplied only by the hydrogen in the high-pressure pipe 4, it was considered that the pressure change ΔP occurred with less hydrogen consumption than expected, and it was determined that the shut-off valve 3A was closed and malfunctioned. Then, the fault flag is set and the like, and the process proceeds to the fault handling routine of step 280. The hydrogen consumption at this time should be as follows: n1 = P1 · Vpipe / R · T n2 = P2 · Vpipe / R · TM2 = n1 + n2 (shut-off valve 3A in Fig. 3 does not open) Reference numeral 270).

In step 290, the estimated hydrogen consumption M2
Is larger, that is, it is determined that the hydrogen consumption amount M2 actually consumed in the fuel cell 1 is larger than the hydrogen supply amount M1 when the shutoff valve 3A is operating normally.
Since the hydrogen in the high-pressure pipe 4 and the fuel gas were supplied from the two fuel tanks 2A and 2B with the shutoff valve 3B kept open, it is considered that the pressure change ΔP occurred due to the hydrogen consumption larger than expected, and the shutoff valve 3B was considered. Is opened, it is determined that there is a failure, and the failure flag is set, and the procedure proceeds to the failure processing routine of step 280. The hydrogen supply amount at this time should be n1 = (P1 (V1 + V1 + Vpipe)) / R · T n2 = (P2 (V1 + V1 + Vpipe)) / R · T M2 = n1 + n2 as shown in the following formula (FIG. 3). (See reference numeral 290, which does not close the shutoff valve 3B).

In step 300, the shutoff valve 3A is opened according to the command value, or is kept open from the beginning, or
Since it is found that either one of the shutoff valves 3A and 3B is open, first, an open command is issued to the shutoff valve 3B in order to proceed to the next stage of diagnosis.

At step 310, the shutoff valve 3 is continuously operated.
Issue a close command to A.

In step 320, as in step 120, it is determined whether or not a predetermined amount of time has elapsed since the "close" command was issued to the shutoff valve 3A. When the predetermined time has elapsed, the process proceeds to step 330.

In step 330, the fuel gas pressure in the high pressure pipe 4 is measured by the pressure sensor 5, and the value is set to P3. This fuel gas pressure P3 is maintained at the fuel gas pressure P2 which is consumed by the fuel cell 1 and lowered by closing the shutoff valve 3A by opening the shutoff valve 3B to communicate the new fuel tank 2B with the high-pressure pipe 4. The existing fuel tank 2A is shut off. Therefore, the fuel gas pressure should be P3> P2.

In step 340, it is determined whether the difference between P3 and P2 is substantially equal to ΔP. Since the volume of the fuel tank 2B is sufficiently larger than that of the high pressure pipe 4, the shutoff valve 3
If A and 3B are operating normally, fuel gas pressure P3 = P
It should be 2 + ΔP.

In step 350, the fact that it is not equal to ΔP means that the shutoff valve 3B was not opened or the shutoff valves 3A, 3
It is determined that one of the B's is in the open state and the other is in the open state, and the failure flag is set. Then, the process proceeds to the failure processing routine of step 360 (the shutoff valve 3B in FIG. 3). (See reference numeral 350, which remains closed).

In step 370, the fuel gas pressure in the high-pressure pipe 4 is measured again by the pressure sensor 5, and the value is P3.
Then, the temperature of the fuel gas is measured by the temperature sensor 6, and the value is set as T1.

In step 390, the estimated hydrogen supply amount M3 by the fuel gas supply amount determination means 12 when the pressure in the high-pressure pipe 4 decreases by ΔP when the shutoff valve 3A is normally closed and the shutoff valve 3B is open. Is calculated using the following state equation n3 = (P3 (V1 + Vpipe)) / R · T n4 = (P4 (V1 + Vpipe)) / R · T M3 = n3-n4. However, here, P4 = P3-Δ
P and T are T1 expressed in absolute temperature, R is a gas constant, V1 is a fuel tank volume, and Vpipe is a high-pressure pipe 4.
Is the volume of.

In step 400, the estimated hydrogen consumption M4
The initial value of is set to zero.

In step 410, the output current I of the fuel cell 1 is measured by a current sensor (not shown).

In step 420, from the output current I, the Faraday constant F, the control period Ts, and the number of stacked layers n, 1
Assuming that the state of the fuel cell 1 does not change during the control cycle, the amount of hydrogen consumed by the fuel cell 1 during one control cycle δM (mol) δM = I · T · n Calculate / 2 · F.

In step 430, the hydrogen amount δM calculated in step 420 is added to the estimated hydrogen consumption amount M4, and M4 = M4 + δM is set as the hydrogen consumption amount M4 after the fuel cell 1 starts measurement (step 400).

In step 440, the fuel gas pressure in the high-pressure pipe 4 is measured again by the pressure sensor 5, and the value is P
Set to 4.

In step 450, the fuel gas pressures P3 and P
4 is calculated, and it is determined whether the pressure in the high-pressure pipe 4 has decreased by a predetermined differential pressure ΔP due to fuel consumption of the fuel cell 1. If not, step 410
Returning to, the hydrogen amount δM consumed in the next control cycle is calculated, and the estimated hydrogen consumption amount M4 is obtained. If it has fallen, go to step 460.

In step 460, the estimated hydrogen supply amount M3 calculated from the state equation of step 390 is compared with the estimated hydrogen consumption amount M4 obtained from the output current I of the fuel cell 1 of step 430, and the difference is a predetermined value. Check if it is less than or equal to ΔM. In consideration of measurement errors of the current sensor, the temperature sensor 6, the pressure sensor 5, etc., ΔM may be regarded as substantially the same value, and a difference value may be set in advance.

If the difference is less than or equal to the predetermined value ΔM, that is, if it is determined that the values are substantially equal, step 510.
Go to. If the difference is larger than the predetermined value ΔM and it is judged that they cannot be considered equal, the process proceeds to step 480.

In step 480, it is determined that the amount M4 of hydrogen actually consumed in the fuel cell 1 is larger than the amount M3 of hydrogen supply when the shutoff valves 3A and 3B were operating normally. Since the hydrogen in the high-pressure pipe 4 and the two fuel tanks 2A and 2B were supplied with the fuel while the shutoff valve 3A was open, it was considered that the pressure change ΔP occurred due to the consumption of hydrogen larger than expected, and the shutoff valve 3A It is determined that there is a failure while it is open, and a procedure such as setting a failure flag is performed, and the procedure proceeds to the failure processing routine of step 500. The hydrogen consumption amount M4 at this time should be as in the following formula n3 = (P1 (V1 + V1 + Vpipe)) / R.Tn4 = (P2 (V1 + V1 + Vpipe)) / R.T M4 = n3-n4 (Fig. (See reference numeral 480 with the shutoff valve 3A of No. 3 kept open).

At step 510, since it was found that the shutoff valve 3B was opened as instructed and the shutoff valve 3A was closed as instructed, it is determined that both shutoff valves 3A, 3B are operating normally.

At step 520, the present diagnosis processing is exited.

It should be noted that it is more effective if the pressure difference ΔP is set to a small value within a range in which the pressure sensor 5 can be sufficiently discriminated, because the time required for diagnosis is reduced.

In the description of the above embodiment, the pressure in the high-pressure pipe 4 is measured in steps 300 to 330, and the pressure P3 is measured.
If the difference between P2 and P2 is close to ΔP, step 350
Although the failure of the shut-off valve 3B with closed is determined by, instead of this, although not shown, a step of performing the same determination as step 260 is inserted between step 460 and step 480, You may determine the failure state of the shutoff valve 3A, 3B.

Further, the fuel gas consumption estimating means 11 described above determines the amount of fuel gas consumed in the main body of the fuel cell 1 while the pressure decreases by ΔP as the operating state of the fuel cell 1, that is, the fuel cell 1. Although it was estimated by detecting the output current I, the fuel supply amount detecting means or the fuel flow rate detecting means 2 for detecting the amount of fuel supplied to the main body of the fuel cell 1 is detected.
As shown in FIG. 1, 0 may be provided at the fuel inlet of the fuel cell 1 to directly detect the fuel flow rate passing through while the pressure decreases by ΔP. In this way, the passage flow rate is directly obtained, so that the accuracy of the failure determination of the shutoff valves 3A, 3B can be further improved.

In this embodiment, the effects described below can be obtained. That is, the fuel gas consumption amount estimating means 11 for estimating the amount of fuel gas consumed in the main body of the fuel cell 1, the fuel gas pressure change amount, the fuel gas temperature, the gas supply path 4 volume, and the fuel supply for which the opening command is issued. The fuel gas supply amount estimating means 12 for estimating the amount of fuel gas supplied from the fuel supply source is compared with the fuel gas amount estimated value from the volume of the fuel tank 2A or 2B as the source, and the shutoff valves 3A, 3
In order to determine whether B is normal or defective, the open / closed states of the shutoff valves 3A, 3B can be detected with high accuracy, and the shutoff valve 3 can be more reliably compared with the command of the shutoff valve control means 10.
It is possible to diagnose the failure states of A and 3B.

The fuel gas supply amount estimating means 12 includes the shutoff valve 3
Fuel gas pressure change amount, fuel gas temperature, volume of gas supply path 4 and the volume of fuel tank 2A or 2B to which the opening command is issued, from the volume of fuel tank 2A or 2
In order to estimate the amount of fuel gas supplied from B, even if a plurality of fuel tanks 2A and 2B are arranged, the respective shutoff valves 3A and 3B can be provided without adding a sensor or the like.
It is possible to surely diagnose.

Since the fuel gas consumption estimating means 11 has a fuel cell operating state detecting means for detecting the operating state of the fuel cell 1 and is configured to estimate the fuel gas consumption based on the detection result, the fuel cell 1 This diagnosis can be applied as long as it has a sensor for detecting the state of.

Since the fuel cell operating state detecting means is the fuel cell output current detecting means for detecting the output current I of the fuel cell 1, the present invention can be easily applied by the ammeter attached to the fuel cell 1. .

(Second Embodiment) An embodiment for realizing a vehicle fuel gas supply device according to the present invention is described in claims 1, 3
5 to 5 will be described based on the second embodiment.
4 and 5 show a vehicle fuel gas supply device according to a second embodiment, FIG. 4 is a system configuration diagram of the fuel gas supply device of the fuel cell 1, and FIG. The control flowchart of the failure diagnosis performed is shown. The difference between this embodiment and the previous embodiment is that the fuel tanks 2A, 2B are
The point is that different volumes are used.

In FIG. 4, the fuel tank 2A has a volume of V
1 and the fuel tank 2B has a volume V2 larger than 2A.
have.

The details of the failure diagnosis executed by the controller 7 will be described below with reference to the flowchart of FIG. In the flowchart, the operation of the fuel gas consumption amount estimating means 11 is performed in steps 1200 to 1250 and steps 1370 to 1420, and the fuel gas supply amount estimating means 12 is used.
Steps 1130 to 1180, and the shutoff valve state determination means 13 operates in Steps 1260, 1280 to 1330 and Steps 1430 to 1450, 1470 to 1520.
However, each is applicable.

In step 1100, it is determined whether or not a start signal has been issued to the fuel cell 1. If the activation signal has not been issued, wait until the activation signal comes. If the activation signal is issued, the process proceeds to step 1110.

At step 1110, the shutoff valve control means 1
From 0, an open command is output to the shutoff valves 3A and 3B.

At step 1120, the shutoff valves 3A, 3B are
It is determined whether or not a predetermined amount of time has elapsed since the "open" command was issued. When the predetermined time has elapsed, the process proceeds to step 1130.

In step 1130, the fuel gas pressure in the high-pressure pipe 4 is measured by the pressure sensor 5, and the value is set to Pl.

In step 1140, the temperature of the fuel gas is measured by the temperature sensor 6, and the value is set as T1.

In step 1150, the estimated hydrogen supply amount Ml when the pressure in the high-pressure pipe 4 when the shutoff valve 3A is closed and the shutoff valve 3B is closed is reduced to ΔP by being supplied to the fuel cell 1 is as follows. N1 = (P1 · Vpipe) / R · T n2 = (P2 · Vpipe) / R · T M1 = n1−n2. However, here, P2 =
P1-ΔP, T is the absolute temperature of T1, R
Is the gas constant and Vpipe is the volume of the high-pressure pipe.

In step 1160, the estimated hydrogen supply amount M2 when the pressure in the high-pressure pipe 4 when the shutoff valve 3A is opened and the shutoff valve 3B is closed is supplied to the fuel cell 1 and decreases by ΔP is as follows. N1 = (P1 (V1 + Vpipe) / R * Tn2 = (P2 (V1 + Vpipe) / R * TM2 = n1-n2) where V1 is the volume of the fuel tank 3A. .

In step 1170, when the shutoff valve 3A is closed and the shutoff valve 3B is open, the pressure in the high-pressure pipe 4 is supplied to the fuel cell 1 and decreases by ΔP. N1 = (P1 (V2 + Vpipe) / R * Tn2 = (P2 (V2 + Vpipe) / R * TM3 = n1-n2) where V2 is the volume of the fuel tank 3B. .

In step 1180, the estimated hydrogen supply amount M4 when the pressure in the high-pressure pipe 4 when the shutoff valve 3A is open and the shutoff valve 3B is also open is reduced to ΔP by being supplied to the fuel cell 1 is as follows. N1 = (P1 (V1 + V2 + Vpipe)) / R · T n2 = (P2 (V1 + V2 + Vpipe)) / R · T M4 = n1-n2 Calculated using the equation of state.

In step 1190, the fuel cell 1 is actually started and the fuel consumption from the high pressure pipe 4 is started.

In step 1200, the estimated hydrogen consumption M
The initial value of 5 is set to zero.

In step 1210, the output current I of the fuel cell 1 is measured by a current sensor (not shown).

At step 1220, assuming that the output current 1, the Faraday constant F, and the control cycle Ts do not change the state of the fuel cell 1 during one control cycle, the following equation is used to obtain δM = IT / 2. -Amount of hydrogen δM consumed in the fuel cell 1 during the F 1 control cycle
(Mol) is calculated.

In step 1230, step 1220
The estimated hydrogen consumption amount M5 is added to the hydrogen amount δM calculated in step S1 by the following equation, and M5 = M5 + δM The hydrogen consumption amount M5 after the fuel cell 1 starts measurement (in this case, operation).

In step 1240, the fuel gas pressure in the high pressure pipe is measured again by the pressure sensor 5, and the measured value is P5.
And

In step 1250, the difference between the fuel gas pressures P1 and P5 is calculated, and it is determined whether the pressure in the high pressure pipe 4 has decreased by a predetermined differential pressure ΔP due to the fuel consumption of the fuel cell 1. . If it has not decreased, the process returns to step 1210, and the hydrogen amount δM consumed in the next control cycle is increased.
Is calculated, and the estimated hydrogen consumption amount M5 is obtained again. If the pressure difference ΔP has decreased, the process proceeds to step 1260.

In step 1260, step 1230
It is determined whether the estimated hydrogen consumption amount M5 in step 1180 is equal to the estimated hydrogen supply amount M4 in step 1180. If it is determined that they are substantially equal, the process proceeds to step 1270, and if they are not equal, the process proceeds to step 1280.

At step 1270, it is judged that the estimated hydrogen consumption amount M5 consumed by the fuel cell 1 is opened as commanded by both the shutoff valves 3A and 3B and the fuel gas is supplied from both the fuel tanks 2A and 2B. Processing such as setting, resetting, etc., and proceeds to step 1340.

In step 1280, the estimated hydrogen consumption M
5 and the estimated hydrogen supply amount M3 in step 1170 are equal to each other. If it is determined that they are substantially equal, the process proceeds to step 1290, and if it is determined that they are not equal, the process proceeds to step 1300.

At step 1290, it is determined that the estimated hydrogen consumption amount M5 consumed by the fuel cell 1 is such that the shutoff valve 3A does not open according to the command, 3B does not open according to the command, and fuel is supplied only from the fuel tank 2B. However, assuming that the shut-off valve 3A is in the closed state, the flag is set and reset, and the processing proceeds to the failure processing routine of step 1330.

In step 1300, the estimated hydrogen consumption M
5 and the estimated hydrogen supply amount M2 in step 1160 are equal to each other. If it is judged that they are almost equal, step 1
Proceed to step 310, and if it is determined that they are not equal, step 1
Proceed to 320.

In step 1310, the hydrogen consumption amount M5 consumed in the fuel cell 1 causes the shutoff valve 3A to open according to the command, the shutoff valve 3B does not open according to the command, and the fuel tank 2A
It is determined that the fuel has been supplied only from the above, it is determined that the shutoff valve 3B is in a closed state, and the flag is set, reset, and the like are performed, and the process proceeds to the fault handling routine of step 1330.

In step 1320, the hydrogen consumption amount M5 consumed in the fuel cell 1 does not open the shut-off valve 3A according to the command and 3B does not open according to the command, and the fuel tanks 2A, 2
Fuel was not supplied from B, and it was judged that only the fuel gas remaining in the high-pressure pipe 4 in the previous run was supplied, and the shutoff valve 3
Assuming that both A and 3B are in the closed state, the process of setting and resetting the flag is performed, and step 133
The process proceeds to the failure processing routine of 0.

At step 1340, the shutoff valve control means 1
From 0, a closing command is output to the shutoff valves 3A and 3B.

In step 1350, the fuel gas pressure in the high pressure pipe 4 is measured by the pressure sensor 5, and the value is set to P1.

In step 1360, the fuel gas temperature T1 is measured by the temperature sensor 6, and the value is set as T1.

At step 1370, the estimated hydrogen consumption M
The initial value of 5 is set to zero.

At step 1380, the output current I of the fuel cell 1 is measured by a current sensor (not shown).

At step 1390, from the output current I, the Faraday constant F, the control period Ts, and the number of stacked layers n,
Assuming that the state of the fuel cell 1 does not change during one control cycle, the hydrogen amount δM (mol) consumed in the fuel cell 1 during one control cycle is calculated.

In step 1400, step 1390
Add the hydrogen amount δM calculated in step 5 to the estimated hydrogen consumption amount M5 (M
5 = M5 + δM), and the fuel cell 1 starts the measurement (step 1370) and sets the hydrogen consumption amount M5.

In step 1410, the fuel gas pressure in the high-pressure pipe 4 is measured again by the pressure sensor 5, and the value is P
Set to 5.

In step 1420, the difference between the fuel gas pressures Pl and P5 is calculated, and it is determined whether or not the pressure in the high pressure pipe 4 has decreased by a predetermined differential pressure ΔP due to the fuel consumption of the fuel cell 1. . If it has not decreased, the process returns to step 1380, and the amount of hydrogen consumed in the next control cycle δM
Is calculated, and the estimated hydrogen consumption amount M5 is obtained again. If the pressure difference ΔP has decreased, the process proceeds to step 1430.

At step 1430, the estimated hydrogen consumption M
5 and the estimated hydrogen supply amount M1 in step 1150 are equal or not. If it is determined that they are substantially equal, the process proceeds to step 1440, and if it is determined that they are not equal, the process proceeds to step 1470.

In step 1440, the hydrogen consumption amount M5 consumed in the fuel cell 1 is closed as instructed by both the shutoff valves 3A and 3B, fuel is not supplied from either of the fuel tanks 2A and 2B, and the high pressure pipes are not supplied. It is judged that the operation was performed only with the residual hydrogen of No. 4.

At step 1450, the shutoff valves 3A and 3B are connected.
It is determined that both can be normally opened and closed, and processing such as flag setting and resetting is performed, and the flow advances to step 1460 to exit the failure diagnosis processing.

At step 1470, the estimated hydrogen consumption amount M
5 and the estimated hydrogen supply amount M2 in step 1160 are equal to each other. If it is determined that they are substantially equal, the process proceeds to step 1480, and if it is determined that they are not equal, the process proceeds to step 1490.

In step 1480, it is determined that the hydrogen consumption amount M5 consumed in the fuel cell 1 is such that the shutoff valve 3A does not close according to the command, 3B does not close according to the command, and the fuel gas is supplied from the fuel tank 2A. It is assumed that the shut-off valve 3A is in the open state, and processing such as flag setting and reset is performed, and the flow proceeds to the failure processing routine of step 1520.

At step 1490, the estimated hydrogen consumption M
5 and the estimated hydrogen supply amount M3 in step 1170 are equal to each other. If it is determined that they are substantially equal, the process proceeds to step 1500, and if it is determined that they are not equal, the process proceeds to step 1510.

In step 1500, the hydrogen consumption amount M5 consumed in the fuel cell 1 causes the shutoff valve 3A to close according to the command, the shutoff valve 3B does not close according to the command, and the fuel tank 2B is closed.
It is determined that the fuel gas has been supplied from the above, it is determined that the shutoff valve 3B is in the open state, and the flag is set, resetting, and the like are performed, and the process proceeds to the fault handling routine of step 1520.

In step 1510, the hydrogen consumption amount M5 consumed in the fuel cell 1 does not cause the shutoff valve 3A to close according to the command and the shutoff valve 3B also does not close according to the command.
It is judged that fuel has been supplied from A and 2B, and the shutoff valve 3A,
It is assumed that both 3B are in the open state, and processing such as flag setting and resetting is performed, and the flow proceeds to the failure processing routine of step 1520.

In the above example, the fuel tanks 2A, 2B are
When the volumes are different, the opening / closing of the shutoff valves 3A and 3B is instructed at the same time, but it is also possible to issue the commands in order as in the previous embodiment to make the determination.

In this embodiment, in addition to the effects of the first embodiment, a plurality of fuel tanks 2A, 2B are provided.
Is composed of fuel tanks having different volumes, the plurality of shutoff valves 3A and 3B are provided.
Diagnosis can be made by opening and closing B a few times.

(Third Embodiment) An embodiment for realizing a vehicle fuel gas supply system according to the present invention is described in claim 1.
A description will be given based on the third embodiment corresponding to Nos. 2, 4, and 5.

FIG. 6 is a system configuration diagram of a fuel gas supply device for a fuel cell according to a third embodiment of the present invention, FIG.
Is a control flowchart of failure diagnosis executed by the controller, and FIG. 8 is a time chart showing the operating state of the shutoff valve in the failure diagnosis. The difference between this embodiment and the previous embodiment is that the fuel tanks 2A, 2B are 3A1, respectively.
That is, two shutoff valves 3A2, 3B1 and 3B2 are provided in series. Such a form is often used especially when applied to a vehicle.

Details of the failure diagnosis executed by the controller 7 will be described below with reference to the flowchart of FIG. In the flowchart, the operations of the fuel gas consumption amount estimating means 11 and the fuel gas supply amount estimating means 12 are set as steps 2120, 2180, 2230, 2290.
The operation of the shutoff valve state determination means 13 is performed in steps 2130 to 2160, 2190 to 2210, and 224.
0 to 2280 and 2300 to 2330 correspond respectively.

In step 2100, it is determined whether or not a start signal has been issued to the fuel cell 1. If the activation signal has not been issued, wait until the activation signal comes. If the activation signal is issued, the process proceeds to step 2110.

At step 2110, the shutoff valve control means 1
From 0, an open command is output to the shutoff valves 3A1, 3A2, 3B1.

In step 2120, step 1 in FIG.
Similar to 20 to 240, the fuel gas pressure and temperature of the high-pressure pipe 4 are measured after a lapse of a predetermined time, and the estimated hydrogen supply amount M1 at which the fuel gas pressure decreases by ΔP is calculated, while the fuel cell 1 is activated and estimated. The estimated hydrogen consumption amount M2 is calculated by integrating the hydrogen consumption amount δM in the control cycle corresponding to the output current I of the fuel cell 1 until the initial value of the hydrogen consumption amount M2 is zero and the pressure drop of the fuel gas pressure reaches ΔP. To do.

In step 2130, the estimated hydrogen supply amount M
1 and the estimated hydrogen consumption M2 are compared, and the difference is a predetermined value Δ
Check whether it is less than or equal to M. If the difference is less than or equal to the predetermined value, the process proceeds to step 2170, and if it is greater than the predetermined value, the process proceeds to step 2140.

At step 2140, the estimated hydrogen supply amount M
It is determined which of 1 and the estimated hydrogen consumption M2 is larger. Step 21 if the estimated hydrogen supply amount M1 is larger
If the estimated hydrogen consumption amount M2 is greater than 50, the process proceeds to step 2160.

At step 2150, the estimated hydrogen supply amount M
1 is larger, that is, the fuel is supplied only by hydrogen in the high-pressure pipe 4, and it is determined that one or both of the shutoff valves 3A1 and 3A2 is "failed while closed", and a failure flag is set. Step 21
Proceed to the failure processing routine 65. This shutoff valve open / closed state is indicated by reference numeral 2150 in FIG. 8.

At step 2160, it is determined that the hydrogen consumption amount M2 actually consumed in the fuel cell 1 is larger, and the hydrogen gas in the high-pressure pipe 4 and the fuel gas are supplied to the two fuel tanks, and the fuel gas is shut off. It is determined that the valve 3B2 is "failed while the valve remains open", and a measure such as setting a failure flag is taken, and the procedure goes to the failure processing routine of step 2165. This shutoff valve open / closed state is indicated by reference numeral 2160 in FIG. 8.

At step 2170, the shutoff valve control means 1
When 0, a “close” command is output to the shutoff valve 3B1 and an “open” command is output to the shutoff valve 3B2.

In step 2180, step 1 in FIG.
Similarly to 20 to 240, the fuel gas pressure and the temperature of the high-pressure pipe 4 are measured after a lapse of a predetermined time, and the estimated hydrogen supply amount M1 at which the fuel gas pressure decreases by ΔP is calculated, while the fuel cell is started to estimate the hydrogen. The hydrogen consumption amount δM in the control cycle corresponding to the output current I of the fuel cell 1 is integrated to calculate the estimated hydrogen consumption amount M2 until the initial value of the consumption amount M2 is set to zero and the pressure drop of the fuel gas pressure reaches ΔP. .

At step 2190, the estimated hydrogen supply amount M
1 and the estimated hydrogen consumption M2 are compared, and the difference is a predetermined value Δ
Check whether it is less than or equal to M. If the difference is less than or equal to the predetermined value, the process proceeds to step 2220, and if it is greater than the predetermined value, the process proceeds to step 2200.

In step 2200, it is determined that the hydrogen consumption amount M2 actually consumed in the fuel cell 1 is larger, and the hydrogen gas in the high pressure pipe 4 and the fuel gas are supplied to the two fuel tanks 2A and 2B. Yes, it is determined that the shutoff valve 3B1 is "failed while the valve remains open", and a procedure such as setting a failure flag is performed, and the process proceeds to the failure processing routine of step 2210. This shutoff valve open / close state is indicated by reference numeral 220 in FIG.
It is indicated by 0.

At step 2220, the shutoff valve control means 1
0 outputs a “close” command to the shutoff valve 3A2 and an “open” command to the shutoff valve 3B1.

In step 2230, step 1 in FIG.
Similar to 20 to 240, the fuel gas pressure and temperature of the high-pressure pipe 4 are measured after a lapse of a predetermined time, and the estimated hydrogen supply amount M1 at which the fuel gas pressure decreases by ΔP is calculated, while the fuel cell 1 is activated and estimated. The estimated hydrogen consumption amount M2 is calculated by integrating the hydrogen consumption amount δM in the control cycle corresponding to the output current I of the fuel cell 1 until the initial value of the hydrogen consumption amount M2 is zero and the pressure drop of the fuel gas pressure reaches ΔP. To do.

At step 2240, the estimated hydrogen supply amount M
1 and the estimated hydrogen consumption M2 are compared, and the difference is a predetermined value Δ
Check whether it is less than or equal to M. If the difference is less than or equal to the predetermined value, the process proceeds to step 2280, and if it is greater than the predetermined value, the process proceeds to step 2250.

At step 2250, the estimated hydrogen supply amount M
It is determined which of 1 and the estimated hydrogen consumption M2 is larger. Step 22 if the estimated hydrogen supply amount M1 is larger
60, the process proceeds to step 2270 if the estimated hydrogen consumption amount M2 is larger.

At step 2260, the estimated hydrogen supply amount M
1 is larger, that is, the fuel is supplied only by the hydrogen in the high-pressure pipe 4, and it is determined that one or both of the shutoff valves 3B1 and 3B2 are “closed and failed”, and the failure flag is set. Step 22
Proceed to the failure processing routine of 75. This shutoff valve open / closed state is indicated by reference numeral 2260 in FIG. 8.

In step 2270, it is determined that the hydrogen consumption amount M2 actually consumed in the fuel cell 1 is larger, and the hydrogen in the high pressure pipe 4 and the fuel gas are supplied to the two fuel tanks 2A and 2B. Yes, the shut-off valve 3A2 is determined to be "failed while the valve remains open", and a procedure such as setting a failure flag is performed, and the process proceeds to the failure processing routine of step 2275. This shutoff valve open / close state is indicated by reference numeral 227 in FIG.
It is indicated by 0.

At step 2280, the shutoff valve control means 1
When 0, a “close” command is output to the shutoff valve 3A1 and an “open” command is output to the shutoff valve 3A2.

In step 2290, step 1 in FIG.
Similar to 20 to 240, the fuel gas pressure and temperature of the high-pressure pipe 4 are measured after a lapse of a predetermined time, and the estimated hydrogen supply amount M1 at which the fuel gas pressure decreases by ΔP is calculated, while the fuel cell 1 is activated and estimated. The estimated hydrogen consumption amount M2 is calculated by integrating the hydrogen consumption amount δM in the control cycle corresponding to the output current I of the fuel cell 1 until the initial value of the hydrogen consumption amount M2 is zero and the pressure drop of the fuel gas pressure reaches ΔP. To do.

At step 2300, the estimated hydrogen supply amount M
1 and the estimated hydrogen consumption M2 are compared, and the difference is a predetermined value Δ
Check whether it is less than or equal to M. If the difference is equal to or smaller than the predetermined value, the process proceeds to step 2330, and if it is larger than the predetermined value, the process proceeds to step 2310.

In step 2310, it is determined that the hydrogen consumption amount M2 actually consumed in the fuel cell 1 is larger, and the hydrogen in the high-pressure pipe 4 and the fuel gas are supplied to the two fuel tanks 2A and 2B. Yes, the shut-off valve 3A1 is determined to be "failed while the valve is open", and a procedure such as setting a failure flag is performed, and the process proceeds to the failure processing routine of step 2320. This shutoff valve open / close state is indicated by reference numeral 231 in FIG.
It is indicated by 0.

At step 2330, the shutoff valves 3A1 and 3A3
It is determined that both A2, 3B1 and 3B2 can be opened and closed normally, and processing such as flag setting and reset is performed, and step 2
The process proceeds to 340 and exits from the failure diagnosis process.

In addition to the effects of the first embodiment, the present embodiment has the shut-off valves 3A1, 3A2, 3B1 and 3B2 arranged in series for each fuel tank 2A and 2B, so that they are connected in series. Shut off valves 3A1, 3A2, or
It is extremely unlikely that both 3B1 and 3B2 will fail due to "opening", and the risk that fuel gas will be discharged from the fuel tanks 2A and 2B can be extremely reduced. Moreover, there is an effect that the failure diagnosis of the shutoff valve can be efficiently performed.

[Brief description of drawings]

FIG. 1 is a system configuration diagram of a vehicle fuel gas supply device showing an embodiment of the present invention.

FIG. 2A is a first flow chart of failure diagnosis by the controller.

[FIG. 2B] FIG. 2A also shows a fault diagnosis by the controller.
Flowchart following.

[Fig. 2C] Fig. 2B also shows a fault diagnosis by the controller.
Flowchart following.

FIG. 3 is a time chart showing an operating state of a shutoff valve.

FIG. 4 is a system configuration diagram of a vehicle fuel gas supply device showing a second embodiment of the present invention.

FIG. 5A is a first flow chart of failure diagnosis by the controller as well.

[Fig. 5B] Fig. 5A also shows a fault diagnosis by the controller.
Flowchart following.

[Fig. 5C] Fig. 5B also shows a fault diagnosis by the controller.
Flowchart following.

[Fig. 5D] Fig. 5C also shows a fault diagnosis by the controller.
Flowchart following.

FIG. 6 is a system configuration diagram of a vehicle fuel gas supply device showing a third embodiment of the present invention.

FIG. 7A is a first flow chart of failure diagnosis by the controller.

[FIG. 7B] FIG. 7A is also a diagram of failure diagnosis by the controller.
Flowchart following.

FIG. 8 is a time chart showing the operating state of the shutoff valve.

[Explanation of symbols]

1 fuel cell 2A, 2B Fuel tank 3A, 3B, 3A1, 3A2, 3B1, 3B2 Shut-off valve 4 high pressure piping 5 Pressure sensor 6 Temperature sensor 7 controller 10 Shut-off valve control means 11 Fuel gas consumption estimation means 12 Fuel gas supply amount estimation means 13 Shutoff valve state determination means

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Takashi Ino             Nissan, Takaracho, Kanagawa-ku, Yokohama-shi, Kanagawa Nissan             Inside the automobile corporation F-term (reference) 5H027 BA13 KK05 KK44 KK56 MM09

Claims (5)

[Claims] 1. A fuel gas supply device for a vehicle, comprising a shutoff valve, a pressure sensor and a temperature sensor in a gas supply path for supplying a fuel gas from a fuel gas supply source to a fuel cell. Fuel gas consumption estimation means for estimating the amount of gas, shut-off valve control means for determining the open / closed state of the shut-off valve, fuel gas pressure change amount, fuel gas temperature, gas supply path volume, and open command are issued. A fuel gas supply amount estimation means for estimating the amount of fuel gas supplied from the fuel supply source from the volume of the fuel supply source, and a shutoff valve comparing the fuel gas supply amount estimated value and the fuel gas consumption amount estimated value. A fuel gas supply device for a vehicle, comprising: a shutoff valve state determination means for determining whether the engine is normal or has a failure. 2. The fuel gas supply source is composed of a plurality of fuel gas tanks, and the gas supply path includes a shutoff valve installed at a supply port of each fuel gas tank and a downstream of each shutoff valve. The fuel gas supply device for a vehicle according to claim 1, wherein the fuel gas supply device for a vehicle comprises a gas supply pipe that is connected to the fuel cell and communicates with the fuel cell. 3. The fuel gas supply device for a vehicle according to claim 2, wherein the plurality of fuel gas tanks are formed of fuel gas tanks having different volumes. 4. The fuel gas consumption estimating means has a fuel cell operating state detecting means for detecting an operating state of the fuel cell, and estimates the fuel gas consumption based on the detection result. The vehicle fuel gas supply device according to any one of claims 1 to 3. 5. The fuel gas supply system for a vehicle according to claim 4, wherein the fuel cell operating state detecting means is a fuel cell output current detecting means for detecting an output current of the fuel cell.