JP2004063205A - Fuel cell vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell vehicle which can correctly calculate out a continuously drivable distance even when a driving state of a fuel cell is changed. <P>SOLUTION: A remaining fuel amount detecting means 201 detects the amount of a remaining fuel on the basis of a temperature from a tank temperature sensor 21 and a pressure from a tank pressure sensor 22. A first predicted fuel consumption rate calculating means 202 calculates out a predicted consumption rate (a first predicted fuel consumption rate) of hydrogen contributing to power generation in a fuel cell stack 3 on the basis of a stack current. A second predicted fuel consumption rate calculating means 203 calculates out a predicted consumption rate (a second predicted fuel consumption rate) of hydrogen not contributing to power generation on the basis of the stack current and a flow rate of hydrogen at a tank outlet detected by a hydrogen flow rate sensor 20 at the tank outlet. A continuously drivable distance calculating means 204 calculates out a continuously drivable distance of a vehicle on the basis of the amount of the remaining fuel, the first predicted fuel consumption rate and the second predicted fuel consumption rate and outputs the distance to a continuously drivable distance-displaying device 19. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a fuel cell vehicle powered by a fuel cell, and more particularly to a technology for displaying a cruising distance of the fuel cell vehicle.
[0002]
[Prior art]
Japanese Patent Application Laid-Open No. 2001-231109 discloses a conventional technology related to the display of the cruising range of a vehicle, which displays a cruising range based on a fuel amount in a vehicle equipped with a heat engine and a motor powered by a fuel cell. Is disclosed.
[0003]
Further, Japanese Patent Application Laid-Open No. 9-98505 discloses that a traveling distance of a vehicle and an amount of remaining energy of the vehicle are detected, a plurality of sets of data are stored, and a least square method is used based on the stored data. An apparatus for calculating and displaying a cruising distance of a vehicle is disclosed.
[0004]
From such a conventional technique, a device that calculates and displays a cruising distance of a vehicle based on a change in a remaining amount of hydrogen or the like serving as fuel of a fuel cell can be considered.
[0005]
[Problems to be solved by the invention]
However, the cause of the change in the fuel consumption rate in the fuel cell is not only the change in the required load according to the vehicle running state, but also the fuel purge performed to prevent flooding (water overflow) according to the operating state of the fuel cell. There is a change in fuel consumption that does not contribute to power generation of the fuel cell, such as fuel consumption or fuel consumed in a combustor or the like for warming up the fuel cell.
[0006]
Such fuel consumption changes according to changes in the operating state of the fuel cell, and changes due to factors different from changes in the running state of the vehicle.
[0007]
Therefore, in the above-described conventional technology, the cruising distance is calculated based on the change in the cruising distance and the remaining fuel amount. Therefore, the cruising distance of a vehicle traveling by an electric motor using a fuel cell as a power source is calculated as the cruising distance of the fuel cell. There is a problem that it cannot be accurately calculated according to the state.
[0008]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention provides a fuel cell vehicle equipped with an electric motor powered by a fuel cell as a driving force source, and a remaining fuel amount detecting means for detecting a remaining amount of fuel in the fuel cell; First predicted fuel consumption rate calculating means for predicting a first predicted fuel consumption rate which is a consumption rate of fuel contributing to power generation, and second predicted fuel consumption being a consumption rate of fuel not contributing to power generation of the fuel cell Second predicted fuel consumption rate calculating means for predicting a rate, and a cruising range for calculating a cruising distance of the vehicle based on the remaining fuel amount, the first predicted fuel consumption rate, and the second predicted fuel consumption rate. The gist of the present invention is to include a possible distance calculation unit and a display unit for displaying the cruising range.
[0009]
【The invention's effect】
According to the present invention, in a vehicle provided with an electric motor driven by a fuel cell as a power source, the remaining fuel amount of the fuel cell is detected, and the consumption rate of the fuel contributing to the power generation of the fuel cell is set to the first value. The predicted fuel consumption rate is predicted, and the consumption rate of the fuel that does not contribute to the power generation of the fuel cell is predicted as the second predicted fuel consumption rate. Then, a cruising distance of the vehicle is calculated and displayed based on the remaining fuel amount, the first expected fuel consumption rate, and the second expected fuel consumption rate.
[0010]
Thus, in response to the change in the required load according to the running state of the vehicle, the consumption rate of the fuel contributing to the power generation of the fuel cell is predicted, and in response to the change in the operating state of the fuel cell, Since the consumption rate of fuel that does not contribute to power generation is predicted, the consumption rate can be predicted for each fuel consumption factor. Therefore, the fuel consumption rate can be predicted in accordance with changes in the running state of the vehicle and the operating state of the fuel cell, so that the cruising distance can be calculated with high accuracy.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic configuration diagram illustrating a configuration of a first embodiment of a fuel cell vehicle according to the present invention. In FIG. 1, a fuel cell vehicle includes an ejector 1, a hydrogen circulation channel 2, a fuel cell stack 3, a hydrogen purge valve 4, an exhaust hydrogen combustor 5, a compressor 6, an air supply channel 7, a hydrogen inlet temperature sensor 8, hydrogen Inlet pressure sensor 9, combustor temperature sensor 10, exhaust air flow path 11, air pressure control valve 12, controller 13 for calculating range, hydrogen pressure control valve 14, air inlet pressure sensor 15, air flow sensor 16, current A sensor 17, a voltage sensor 18, a cruising distance display device 19 for displaying a cruising distance, a tank outlet hydrogen flow sensor 20, a tank temperature sensor 21, a tank pressure sensor 22, a hydrogen tank 23, a speed sensor 24 for detecting a vehicle speed, A power converter 25 that converts the power generated by the fuel cell stack 3 into AC power, and drives the vehicle with the AC power of the power converter 25. It is equipped with an electric motor 26,.
[0012]
Hydrogen supplied from the hydrogen tank 23 is supplied to the ejector 1 via the hydrogen pressure control valve 14. The hydrogen is mixed with the hydrogen that has passed through the hydrogen circulation channel 2 in the ejector 1 and is supplied to the fuel cell stack 3. The temperature and pressure of hydrogen at the inlet of the fuel cell stack 3 are measured by a hydrogen inlet temperature sensor 8 and a hydrogen inlet pressure sensor 9, respectively. The control of the hydrogen pressure control valve 14 is performed by the pressure measured by the hydrogen inlet pressure sensor 9. Normally, the hydrogen purge valve 4 is directed to flow hydrogen discharged from the fuel cell stack 3 into the hydrogen circulation channel 2.
[0013]
The hydrogen flow supplied from the hydrogen tank 23 is measured by a tank outlet hydrogen flow sensor 20, and the temperature and pressure in the hydrogen tank 23 are measured by a tank temperature sensor 21 and a tank pressure sensor 22, respectively. The amount of hydrogen in the hydrogen tank 23, that is, the remaining amount of fuel is calculated by the controller 13 from the tank volume, the tank temperature, and the tank pressure as described later.
[0014]
Air serving as an oxidant is supplied by the compressor 6. The air supplied by the compressor 6 is measured by the air flow sensor 16 and then supplied to the fuel cell stack 3. The air pressure at the inlet of the fuel cell stack 3 is measured by an air inlet pressure sensor 15 and controlled by an air pressure control valve 12. The air discharged from the fuel cell stack 3 (hereinafter referred to as discharged air) is discharged into the atmosphere via a discharged hydrogen combustor 5.
[0015]
The output current of the fuel cell stack 3 is measured by a current sensor 17, and the output voltage is measured by a voltage sensor 18.
[0016]
In the present embodiment, the operating pressure of the fuel cell stack 3 is variable. That is, when the output taken out of the fuel cell stack 3 is high, the operating pressure is increased, and when the output is low, the operating pressure is reduced.
[0017]
The hydrogen purge valve 4 is operated when a water overflow (hereinafter, flooding) or the like occurs in the fuel cell stack 3 or when the operating pressure of the fuel cell stack 3 is reduced, so that the hydrogen circulation flow path 2 and the fuel cell stack 3 Is discharged to the exhaust hydrogen combustor 5.
[0018]
The exhaust hydrogen combustor 5 performs a process of reacting the discharged hydrogen (hereinafter, exhaust hydrogen) with the exhaust air to generate harmless steam. The temperature of the exhaust hydrogen combustor 5 at that time is measured by the combustor temperature sensor 10.
[0019]
The cruising distance display device 19 displays the value of the cruising distance calculated by the controller 13 on, for example, an instrument panel of the vehicle to notify the driver.
[0020]
The outputs of all these sensors and the drive signals for the actuators such as the hydrogen purge valve 4 are connected to the controller 13.
[0021]
The operating pressure control controls the hydrogen pressure in accordance with a target value, and the air pressure controls the hydrogen pressure at that time as a target value.
[0022]
FIG. 2 is a functional block diagram illustrating a configuration of the controller 13 according to the first embodiment. The controller 13 is composed of, for example, a microprocessor having a CPU, a memory, and a peripheral interface.
[0023]
The controller 13 includes a remaining fuel amount detecting unit 201 that detects a remaining amount of fuel in the fuel cell, and a first predicted fuel that predicts a first predicted fuel consumption rate that is a consumption rate of fuel that contributes to power generation of the fuel cell. Consumption rate calculating means 202, second predicted fuel consumption rate calculating means 203 for predicting a second predicted fuel consumption rate which is a consumption rate of fuel not contributing to power generation of the fuel cell, remaining fuel amount and first prediction A cruising distance calculating means for calculating a cruising distance of the vehicle based on the fuel consumption rate and the second expected fuel consumption rate.
[0024]
The remaining fuel amount detecting means 201 calculates the amount of hydrogen in the hydrogen tank based on the known capacity of the hydrogen tank 23, the hydrogen tank temperature detected by the tank temperature sensor 21, and the hydrogen tank pressure detected by the tank pressure sensor 22. That is, the remaining fuel amount is detected and output to the cruising distance calculating means 204.
[0025]
The first expected fuel consumption rate calculating means 202 calculates an expected hydrogen consumption rate (first expected fuel consumption rate) of hydrogen contributing to power generation in the fuel cell stack 3 based on the stack current detected by the current sensor 17. Is output to the cruising distance calculation means 204.
[0026]
The second expected fuel consumption rate calculating means 203 does not contribute to the power generation in the fuel cell stack 3 based on the stack current detected by the current sensor 17 and the tank outlet hydrogen flow rate detected by the tank outlet hydrogen flow rate sensor 20. An expected hydrogen consumption rate (second expected fuel consumption rate) is calculated and output to the cruising range calculating means 204.
[0027]
Then, the cruising distance calculating means 204 calculates the cruising distance of the vehicle based on the remaining fuel amount, the first expected fuel consumption rate, and the second expected fuel consumption rate, and sends the calculated cruising distance to the cruising distance display device 19. Output.
[0028]
FIG. 3 is a flowchart illustrating a method of calculating a cruising distance in the first embodiment, and is executed by the controller 13 at regular intervals ΔT (for example, ΔT = 0.01 [sec]).
[0029]
First, in step (hereinafter, step is abbreviated as S) 301, the running distance Trip of the vehicle is integrated based on equation (1).
[0030]
(Equation 1)
Trip = Trip (previous value) + VSP × ΔT (1)
Here, VSP is the vehicle speed [m / sec] detected by the speed sensor 24.
[0031]
In S302, the first fuel (hydrogen) consumption C1 [g] that contributes to the power generation of the stack is integrated based on the equation (2).
[0032]
(Equation 2)
C1 = C1 (previous value) + (2.016 × Nst × i) / (2F) × ΔT (2)
Here, 2.016 is the atomic weight of hydrogen molecules, Nst is the number of series cells constituting the stack, i is the power generation current [A] of the fuel cell stack 3 detected by the current sensor 17, and F is the Faraday constant (hydrogen ion (1 mol total charge). Equation (2) is based on the idea that the number of hydrogen ions corresponding to the time integrated value of the current taken out of the fuel cell is obtained, and the result is multiplied by Nst to be converted into hydrogen weight.
[0033]
In S303, the integration of the second fuel (hydrogen) consumption C2 [g] that does not contribute to the power generation of the fuel cell stack 3 is performed based on Expression (3).
[0034]
[Equation 3]
C2 = C2 (previous value) + {FH- (2.016 × Nst × i) / (2F)} × ΔT (3)
Here, FH is a hydrogen flow rate [g / sec] detected by the tank outlet hydrogen flow rate sensor 20. Equation (3) is based on the idea that a value obtained by subtracting the amount of hydrogen that has contributed to power generation in Equation (2) from the total amount of hydrogen consumed is the amount of hydrogen that does not contribute to power generation.
[0035]
In S304, it is determined whether or not a predetermined time (for example, 600 [sec]) has elapsed since the start of the integration calculation in S301 to S303. If the predetermined time has elapsed, the process proceeds to S305, and if the predetermined time has not elapsed, It proceeds to S307.
[0036]
In S305, the first and second predicted fuel consumption rates E1 and E2 are updated based on equations (4) and (5).
[0037]
(Equation 4)
E1 = C1 / Trip (4)
E2 = C2 / Trip (5)
Here, E1 is a first predicted fuel (hydrogen) consumption rate [g / m] that contributes to power generation, and E2 is a second predicted fuel (hydrogen) consumption rate [g / m] that does not contribute to power generation. .
[0038]
In S306, each integrated value is reset. That is, the values of Trip, C1, and C2 are set to 0.
[0039]
In S307, the calculation of the remaining fuel (hydrogen) amount QH [g] is performed based on the equation (6).
[0040]
(Equation 5)
QH = (2.016 × PT × VT) / (R × TT) (6)
Here, PT is the pressure [Pa] in the hydrogen tank 23 detected by the tank pressure sensor 22, TT is the temperature [K] in the hydrogen tank 23 detected by the tank temperature sensor 21, and VT is the hydrogen tank 23. a volume ^{[m 3],} R is the gas constant.
[0041]
In S308, the cruising range D [km] is calculated from the first and second predicted fuel consumption rates E1 and E2 and the remaining fuel amount QH based on the equation (7).
[0042]
(Equation 6)
D = QH / (E1 + E2) × 1/1000 (7)
In the calculation of the predicted fuel consumption rate in S305, when the second predicted fuel consumption rate E2 is increased or decreased in accordance with the increase or decrease in the number of purges of the fuel cell, the second predicted fuel consumption rate E2 that does not contribute to power generation. Is calculated based on equation (8).
[0043]
(Equation 7)
E2 = k × C2 / Trip
Here, the calculation of the correction coefficient k is performed using the table data having the characteristics as shown in FIG. 4 based on the frequency of the purge. Note that the frequency of the purge may be calculated from the number of times the purge is performed during the elapse of the predetermined time. By calculating the correction coefficient k in this manner, the second expected fuel consumption rate E2 can be increased as the number of purges increases.
[0044]
On the other hand, in the state where the number of purges is expected to increase in accordance with the operating state of the fuel cell, the second predicted fuel consumption rate E2 is corrected to increase, and in the state where the number of purges is expected to decrease, When the correction is made so as to decrease the expected fuel consumption rate E2 of FIG. 2, the correction coefficient k is calculated using the table data having the characteristics as shown in FIGS.
[0045]
In FIG. 5, the stack temperature is detected by a hydrogen inlet temperature sensor 8. As described above, when the number of purges is expected to increase based on the stack temperature, the second predicted fuel consumption rate E2 can be increased.
[0046]
In FIG. 6, the stoichiometric ratio uses the stoichiometric ratio of hydrogen or the stoichiometric ratio of air calculated as a parameter of the hydrogen flow rate control or the air flow rate control in the controller 13. Here, the stoichiometric ratio is the ratio of the amount of hydrogen or the amount of air actually supplied to the amount of hydrogen corresponding to the amount of power generation required for the fuel cell or the amount of air containing oxygen.
[0047]
As described above, when the number of purges is expected to increase based on the stoichiometric ratio, the second predicted fuel consumption rate E2 can be increased.
[0048]
In FIG. 7, the stack operating pressure is detected by the hydrogen inlet pressure sensor 9. As described above, when the number of purges is expected to increase based on the stack operating pressure, the second predicted fuel consumption rate E2 can be increased.
[0049]
In FIG. 8, the stack output change cycle is calculated by the sum of the number of times the stack output exceeds a predetermined output value and the number of times the stack output falls below a predetermined output value in a predetermined time. In this way, if it is expected that the number of purges when the output is reduced is expected to increase based on the stack output change cycle, the second predicted fuel consumption rate E2 can be increased.
[0050]
According to the first embodiment described above, the first predicted fuel consumption rate, which is the consumption rate of the fuel contributing to the power generation of the fuel cell, is predicted in response to the change in the stack power generation current, and the fuel cell Since the second predicted fuel consumption rate, which is the consumption rate of the fuel that does not contribute to the power generation of the fuel cell, is predicted in response to the change in the operating state, the fuel consumption rate can be predicted for each fuel consumption factor. Become like
[0051]
Therefore, the fuel consumption rate can be predicted in accordance with changes in the running state of the vehicle and the operating state of the fuel cell, so that the cruising distance can be calculated with high accuracy.
[0052]
Further, since the second predicted fuel consumption rate is calculated based on a change in a value obtained by subtracting the past fuel consumption rate that has contributed to the power generation of the fuel cell from the past total fuel consumption rate of the fuel cell, The second expected fuel consumption rate can be calculated with a relatively simple configuration.
[0053]
Further, based on the change in the number of purges of the fuel cell, the correction is performed so as to increase or decrease the second expected fuel consumption rate in accordance with the increase or decrease in the number of purges. It can be carried out.
[0054]
Next, a second embodiment of the fuel cell vehicle according to the present invention will be described. This embodiment is an embodiment in which the second predicted fuel consumption rate, which is the consumption rate of the fuel that does not contribute to the power generation of the fuel cell, is not updated while the fuel cell is being warmed up. Note that the configuration of the present embodiment is the same as the configuration of the first embodiment shown in FIGS.
[0055]
FIG. 9 is a flowchart illustrating a method of calculating a cruising distance in the second embodiment. This flowchart is executed at regular intervals ΔT (for example, ΔT = 0.01 [sec]).
[0056]
First, in S900, it is determined whether or not the stack is being warmed up. If the stack is being warmed up, the process proceeds to S907, where the running distance and the fuel consumption are not integrated, and the fuel consumption rate is not updated.
[0057]
On the other hand, if it is not warmed up in S900, the process proceeds to S901. The processing in S901 to S908 is the same as the processing in S301 to S308, respectively. The determination that the engine is warming up depends on the condition that the exhaust hydrogen combustor 5 is operating for warming up and the measured value of the hydrogen inlet temperature sensor 8 or the temperature sensor that measures the temperature of the stack itself. If one or both of the conditions that the temperature of the stack detected based on the temperature is equal to or lower than the predetermined value is satisfied, it is determined that the stack is being warmed up.
[0058]
According to the second embodiment described above, the short-term change in the fuel consumption rate during the warm-up operation of the fuel cell is not reflected in the second predicted fuel consumption rate, so that the cruising distance fluctuates in the short-term. In addition, it is possible to prevent the driver from feeling uneasy.
[0059]
In addition, it is possible to detect the operation / non-operation of the warming-up combustor, and to determine that the fuel cell is in the warming-up operation by detecting the temperature of the fuel cell. It is possible to detect that the battery is being warmed up.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing a configuration of an embodiment of a fuel cell vehicle according to the present invention.
FIG. 2 is a block diagram illustrating a configuration of a controller according to the embodiment of the present invention.
FIG. 3 is a flowchart showing a method for calculating a cruising distance in the first embodiment.
FIG. 4 is a diagram showing an example of table data for calculating a coefficient k for correcting a second expected fuel consumption rate based on a purge frequency.
FIG. 5 is a diagram showing an example of table data for calculating a coefficient k for correcting a second expected fuel consumption rate based on a stack temperature.
FIG. 6 is a diagram showing an example of table data for calculating a coefficient k for correcting a second expected fuel consumption rate based on a stoichiometric ratio.
FIG. 7 is a diagram showing an example of table data for calculating a coefficient k for correcting a second predicted fuel consumption rate based on a stack operating pressure.
FIG. 8 is a diagram showing an example of table data for calculating a coefficient k for correcting a second predicted fuel consumption rate based on a stack output change cycle.
FIG. 9 is a flowchart illustrating a method of calculating a cruising distance in the second embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Ejector 2 Hydrogen circulation channel 3 Fuel cell stack 4 Hydrogen purge valve 5 Exhaust hydrogen combustor 6 Compressor 7 Air supply channel 8 Hydrogen inlet temperature sensor 9 Hydrogen inlet pressure sensor 10 Combustor temperature sensor 11 Exhaust air channel 12 Air pressure Control valve 13 Controller 14 Hydrogen pressure control valve 15 Air inlet pressure sensor 16 Air flow sensor 17 Current sensor 18 Voltage sensor 19 Range sensor 20 Tank outlet hydrogen flow sensor 21 Tank temperature sensor 22 Tank pressure sensor 23 Hydrogen tank 24 Speed sensor 25 Power converter 26 Electric motor

Claims (7)

In a fuel cell vehicle equipped with an electric motor powered by a fuel cell as a driving force source,
Remaining fuel amount detection means for detecting the remaining amount of fuel in the fuel cell;
First predicted fuel consumption rate calculating means for predicting a first predicted fuel consumption rate that is a consumption rate of fuel contributing to power generation of the fuel cell;
Second predicted fuel consumption rate calculating means for predicting a second predicted fuel consumption rate that is a consumption rate of fuel not contributing to power generation of the fuel cell;
Cruising distance calculating means for calculating a cruising distance of the vehicle based on the remaining fuel amount, the first expected fuel consumption rate, and the second expected fuel consumption rate;
A cruising distance display device that displays the cruising distance,
A fuel cell vehicle comprising: The first expected fuel consumption rate calculating means is:
2. The fuel cell vehicle according to claim 1, wherein said means is for calculating a first expected fuel consumption rate based on a change in a past fuel consumption rate that has contributed to power generation of the fuel cell. The second expected fuel consumption rate calculating means is:
Means for calculating a second predicted fuel consumption rate based on a change in a value obtained by subtracting a past fuel consumption rate that has contributed to power generation of the fuel cell from a past total fuel consumption rate of the fuel cell. The fuel cell vehicle according to claim 1. The second expected fuel consumption rate calculating means is:
2. The fuel cell system according to claim 1, further comprising a correction unit configured to perform a correction based on a change in the number of purges of the fuel cell so as to increase or decrease the second predicted fuel consumption rate in accordance with the increase or decrease in the number of purges. 3. The fuel cell vehicle according to 3. The second expected fuel consumption rate calculating means is:
According to the operating state of the fuel cell, the correction is performed so as to increase the second predicted fuel consumption rate in a state where the number of purges is expected to increase, and the second correction is performed in a state where the number of purges is expected to decrease. 5. The fuel cell according to claim 1, further comprising a correction unit configured to correct the second predicted fuel consumption rate so as to reduce the predicted fuel consumption rate. vehicle. The second expected fuel consumption rate calculating means is:
6. The fuel cell according to claim 1, wherein the value of the second predicted fuel consumption rate is not updated when the fuel cell is being warmed up. 7. Fuel cell vehicle. The second expected fuel consumption rate calculating means is:
When the combustor for warming up the fuel cell is operated, and / or when the temperature of the fuel cell is equal to or lower than a predetermined value, the value of the second predicted fuel consumption rate is not updated. The fuel cell vehicle according to claim 1 or any one of claims 3 to 6.

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