JP2005235614A - Air compression system for fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To decrease temperature of a compressed air, and supply the compressed air of an appropriate humidity to a fuel cell stack. <P>SOLUTION: An air compression system for the fuel cell has a water injection part to inject the water to the compressed air. The water injection part is installed at an air intake passage, and constituted in such a way that a plurality of injectors are arranged in the flow direction and the perpendicular direction to the flow of the compressed air. The air compression system for the fuel cell detects the temperature and the humidity of the compressed air. Furthermore, it controls the amount of water to be supplied from an injector. This control is carried out based on the temperature and the humidity of the compressed air. By this, the air compression system for the fuel cell decreases the temperature of a film of the fuel cell stack and can keep an appropriate humidity so as not to cause flooding or dry-out in the fuel cell stack. That is, by the water supply amount control carried out by the air compression system for the fuel cell, the deterioration of the fuel cell stack can be prevented, and utilization efficiency of the fuel cell stack can be improved. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an air compression system for a fuel cell that supplies compressed air to a fuel cell stack or the like.

  An air compression system that supplies compressed air (hereinafter also referred to as “compressed air”) to a vehicle engine, a fuel cell stack, or the like is known. In an air compression system, air is adiabatically compressed by an air compressor (hereinafter also referred to as a “compressor”) or the like, so that the discharged compressed air becomes high temperature. Therefore, if a component having poor heat resistance is incorporated in the apparatus to which the compressed air is supplied, a problem occurs.

  In general, in a fuel cell air compression system used in a fuel cell stack, a technique is used in which water is injected into the compressed air to reduce the temperature of the air flowing into the fuel cell stack. For example, Patent Document 1 discloses a technique in which water is injected into compressed air discharged from an air compressor that takes in air supplied to a fuel cell stack, and the amount of water to be injected is controlled according to the temperature of the compressed air. Has been described. Patent Document 2 describes a technique in which cooling is performed twice with a heat exchanger and an aftercooler before compressed air from a compressor is supplied to a fuel cell stack. In addition, Patent Literature 3 and Patent Literature 4 describe a technique of cooling by injecting water into compressed air.

  Here, in the fuel cell stack, when the moisture in the vicinity of the membrane becomes excessive, it is known that a phenomenon (so-called “flooding”) in which the output performance of the battery is deteriorated by inhibiting gas diffusion occurs. Yes. In addition, it is known that when water supplied to the membrane is insufficient, a phenomenon (so-called “dry-out”) in which the output performance of the battery is lowered occurs due to a decrease in ionic conductivity. As described above, in order not to reduce the output performance of the fuel cell stack, it is necessary to maintain the fuel cell stack at an appropriate humidity.

  However, in the technique disclosed in the above-mentioned document, although the temperature of the compressed air can be lowered, the control is not performed in consideration of the humidity of the compressed air after water is supplied. Therefore, the output performance of the fuel cell may be deteriorated.

JP 2002-115666 A JP 2000-208159 A JP-A-3-9090 JP-T-2001-502396

  The present invention has been made in order to solve such problems. The object of the present invention is to reduce the temperature of compressed air discharged from the compressor and to compress the fuel cell stack with appropriate humidity. An object of the present invention is to provide an air compression system for a fuel cell capable of supplying air.

In one aspect of the present invention, an air compression system for a fuel cell includes an air compression unit that compresses air to be supplied to a fuel cell stack, a water supply unit that sprays and supplies water to the compressed air,
Water for controlling the amount of water to be supplied based on temperature acquisition means for acquiring the temperature of the compressed air, humidity acquisition means for acquiring the humidity of the compressed air, the acquired temperature, and the acquired humidity And a supply amount control means.

  The fuel cell air compression system is a system that compresses air with a compressor or the like and supplies the compressed air (ie, compressed air) to the fuel cell stack. The fuel cell air compression system has water supply means for spraying and supplying water (hereinafter also referred to as “injection”) to the compressed air. This water supply means is constituted by, for example, an injector. The air compression system for a fuel cell can detect the temperature of the compressed air and the humidity of the compressed air by means of a temperature acquisition unit configured by sensors and the humidity acquisition unit. The fuel cell air compression system further includes water supply amount control means for controlling the amount of water supplied from the water supply means. The water supply amount control (hereinafter referred to as “water supply amount control”) performed by the fuel cell air compression system is performed based on the temperature and humidity of the compressed air described above. As described above, the fuel cell air compression system can reduce the temperature of the compressed air to a temperature at which the fuel cell stack does not deteriorate, and can keep the fuel cell stack at an appropriate humidity that does not cause flooding or dryout. it can. That is, the water supply amount control performed by the fuel cell air compression system can prevent deterioration of the compressed fuel cell stack and improve the utilization efficiency of the fuel cell stack.

  In one aspect of the fuel cell air compression system, the water supply amount control means controls the amount of water to be supplied so that the acquired humidity becomes a target humidity. The fuel cell air compression system acquires a target humidity from a map indicating the relationship between the humidity and the output power of the fuel cell stack based on the current situation of the fuel cell stack and the like. The fuel cell air compression system controls the amount of water supply so that the humidity of the compressed air becomes the target humidity. This makes it possible to keep the fuel cell stack at an optimum humidity.

  In another aspect of the fuel cell air compression system, the fuel cell air compression system further includes a flow rate acquisition unit configured to acquire a flow rate of the compressed air, and the water supply amount control unit is configured to supply water based on the flow rate of the compressed air. Control the amount. A flow meter or the like can be used as the flow rate acquisition means. By performing the water supply amount control in consideration of the flow rate of the compressed air, the temperature and humidity of the fuel cell stack can be controlled with higher accuracy.

  In another aspect of the fuel cell air compression system described above, the fuel cell stack temperature acquisition means for acquiring the temperature of the fuel cell stack is provided, and the water supply amount control means is configured such that the temperature of the acquired fuel cell stack is When the temperature is equal to or higher than the predetermined temperature, the amount of the supplied water is increased. The predetermined temperature is a temperature at which deterioration of the fuel cell stack occurs. The fuel cell air compression system performs control to immediately increase the water supply amount when the temperature of the fuel cell stack is equal to or higher than a predetermined temperature. That is, the fuel cell air compression system gives priority to the prevention of deterioration of the fuel cell stack at a high temperature rather than finely controlling the amount of water supplied.

  In another aspect of the fuel cell air compression system, a plurality of the water supply means are provided in the compressed air flow direction. The water supply means is provided in the intake passage through which the compressed air passes. By providing a plurality of water supply means in the flow direction of the compressed air, water can be supplied uniformly into the intake passage. Thus, the fuel cell air compression system can uniformly cool and humidify the compressed air. Further, it is possible to prevent the intake passage from deteriorating due to a rapid temperature change when the compressed air is vaporized.

  In the air compression system for a fuel cell, preferably, a plurality of the water supply means are provided in a direction perpendicular to the flow of the compressed air. This also allows the fuel cell air compression system to uniformly cool and humidify the compressed air.

  Further, in the above air compression system for a fuel cell, preferably, the temperature acquisition means and the humidity acquisition means are provided downstream of the water supply means. By obtaining the temperature and humidity of the compressed air after cooling and humidity adjustment for the water supply means, the water supply amount control can be performed with high accuracy.

  Preferred embodiments of the present invention will be described below with reference to the drawings.

[Configuration of fuel cell air compression system]
FIG. 1 is a schematic configuration diagram showing an air compression system for a fuel cell according to one embodiment of the present invention.

  In FIG. 1, a fuel cell air compression system 100 mainly includes a compressor (air compressor) 1, an intake passage 2, a flow meter 3, a water injection unit 4, a dew point temperature sensor 9, a temperature sensor 10, 11 and a control computer 15. The fuel cell air compression system 100 is mounted on a fuel cell vehicle (hereinafter simply referred to as “vehicle”) or the like, and supplies compressed air to the fuel cell stack 13.

  The fuel cell stack 13 is formed by laminating battery cells in which electrodes having a structure such as a porous layer capable of diffusing gas are formed on both surfaces of an electrolyte membrane (not shown) with a conductive separator interposed between the layers. The output voltage can be taken out according to the number. In the drawing, for convenience of explanation, only the structure of a battery cell in which a cathode electrode (air electrode) 12a and an anode electrode (fuel electrode) 12b are formed on the electrolyte membrane surface is shown. As shown in the drawing, air (air) 22 is supplied to the cathode electrode 12a, and fuel (hydrogen) 23 is supplied to the anode electrode 12b. Thereby, electric power is generated.

  The fuel cell stack 13 is a power supply for a motor for driving the vehicle, and generates a high DC voltage of about 300V. The generated voltage of the fuel cell stack 13 is output to an inverter (not shown) that supplies a current corresponding to a command torque to the motor. Further, the power generation voltage of the fuel cell stack 13 is stepped down by a DC-DC converter and output to various auxiliary machines mounted on the vehicle and a battery as a secondary battery for supplying power to them. Yes.

  The compressor 1 compresses the intake air 20 to generate compressed air 21. The compressed air 21 immediately after being discharged from the compressor 1 is normally 150 ° C. or higher. As the compressor 1, a piston type compressor, a scroll type compressor, a turbo type compressor, or the like can be used. Thus, the compressor 1 functions as an air compression unit that compresses the air supplied to the fuel cell stack 13.

  The flow meter 3 measures the flow rate of the compressed air 21. As the flow meter 3, a venturi flow meter, a hot wire flow meter, or the like can be used. The flow meter 3 outputs a signal S 1 corresponding to the flow rate of the compressed air 21 to the control computer 15.

  The compressed air 21 is cooled by water jetted from the water jet unit 4. The water injection unit 4 is composed of a plurality of injectors. The injector is disposed on the outer wall surface of the intake passage 2. As illustrated, injectors 5a and 5b are provided in the direction perpendicular to the flow of the compressed air 21, and injectors 6a and 6b are provided in the flow direction. In the fuel cell air compression system 100 according to the present embodiment, there are a plurality (two or more) of injectors in the flow direction of the compressed air, and a plurality (two or more) of injectors in the direction perpendicular to the flow of the compressed air. For convenience of explanation, only the injectors 5a, 5b, 6a, and 6b will be described. Moreover, the specific structural example of the water injection part 4 is mentioned later.

  The injectors constituting the water injection unit 4 (hereinafter, when the reference numerals are omitted are used as meanings including all of the above-described injectors 5a, 5b, 6a, 6b) can inject mist-like water. It is a device that can. That is, the water injection unit 4 functions as a water supply unit that sprays and supplies water to the compressed air 21. Further, the amount of water injected from the injector can be adjusted. The water injected from the injector is vaporized by the heat of the compressed air 21 that passes through the intake passage 2 provided with the injector. As a result, the heat of the compressed air 21 is taken and the compressed air 21 is cooled. The injector injects thin screen-like water in a direction perpendicular to the flow of the compressed air 21. Thereby, the injected water becomes easy to vaporize, and the compressed air 21 can be cooled effectively. The compressed air 22 that has passed through the water injection unit 4 as described above is lowered to about 80 ° C., for example. In addition, the water injected from the injector plays a role of not only cooling the compressed air 21 but also humidifying the compressed air 21. That is, the water injection unit 4 can supply moisture to the membrane of the fuel cell stack 13.

  Injectors 5a, 5b, 6a and 6b are controlled by control signals S7a, S7b, S8a and S8b from control computer 15, respectively. That is, the amount of water injected from the injector is adjusted by a control signal from the control computer 15. Details of this specific control will be described later.

  The temperature sensor 9 is attached to the intake passage 2 downstream of the water injection unit 4. Therefore, the temperature sensor 9 detects the temperature of the compressed air 22 after passing through the water injection unit 4. The temperature sensor 9 outputs a signal S2 corresponding to the temperature to the control computer 15.

  The dew point temperature sensor 10 is also attached to the intake passage 2 downstream of the water injection unit 4. The dew point temperature sensor 10 detects a temperature at which moisture in the compressed air 22 is saturated and condensed. The dew point temperature sensor 10 outputs a signal S3 corresponding to the dew point temperature to the control computer 15.

  The temperature sensor 11 is attached on the fuel cell stack 13. That is, the temperature sensor 11 detects the temperature (film temperature) of the fuel cell stack 13. Then, the temperature sensor 11 outputs a signal S4 corresponding to the detected temperature to the control computer 15.

  The control computer 15 includes a CPU, a ROM, a RAM, an A / D converter, an input / output interface, and the like (not shown). The control computer 15 controls the injector in the water injection unit 4 based on the input from the various sensors described above. That is, the control computer 15 controls the injector based on the flow rate of compressed air (signal S1), the temperature of compressed air (signal S2), the humidity of compressed air, and the temperature of the fuel cell stack 13 (signal S4). Control the amount of water supplied to the compressed air. Specifically, the control signals S7a, S7b, S8a, S8b are supplied to the corresponding injectors. As described above, the control computer 15 functions as water supply amount control means for controlling the amount of water supplied to the compressed air 21. In the case where the fuel cell air compression system 100 is mounted on a vehicle or the like, the control computer 15 can have an ECU (Engine Control Unit) in the vehicle play the role.

[Water supply control processing]
Below, the water supply amount control process which the control computer 15 performs is demonstrated using FIGS. This process is performed to cool the compressed air 21 and to set the compressed air 21 to an appropriate humidity for the fuel cell stack 13. For this purpose, the control computer 15 controls the amount of water (hereinafter also referred to as “injection amount”) supplied from the injector to the compressed air 21. The water supply amount control process is repeatedly executed at a predetermined cycle while the fuel cell stack 13 is in use.

  FIG. 2 is a flowchart showing a water supply amount control process performed by the control computer 15.

  First, in step S <b> 11, the control computer 15 acquires the temperature of the fuel cell stack 13. That is, the control computer 15 acquires the signal S4 from the temperature sensor 11. Then, the process proceeds to step S12.

  In step S12, the control computer 15 determines whether or not the temperature of the fuel cell stack 13 is equal to or higher than a predetermined temperature. The predetermined temperature is a temperature at which the fuel cell stack 13 may be deteriorated, and is set to 100 ° C., for example. In step S12, the control computer 15 determines whether or not priority should be given to prevention of deterioration of the fuel cell stack 13 at a high temperature rather than finely controlling the injection amount of water.

  When the temperature of the fuel cell stack 13 is equal to or higher than the predetermined temperature (step S12; Yes), the process proceeds to step S13. In step S13, the control computer 15 determines that the water injection amount of the injector should be increased. That is, the control computer 15 determines the increase in the injection amount while allowing the inside of the membrane to be humidified in order to prevent the fuel cell stack 13 from deteriorating. Then, the process proceeds to step S18. Note that the control computer 15 can also acquire the amount of vaporized water out of the injected water, and accurately calculate the increase value of the injection amount of the injector based on the temperature of the compressed air and the amount of vaporized water. .

  In step S18, the control computer 15 controls the injector so that the increased amount of water is injected. For example, when the temperature of the fuel cell stack 13 greatly exceeds a predetermined temperature, control is performed so that each injector injects the maximum injection amount with respect to all the injectors constituting the water injection unit 4. When the process of step S13 ends, the process exits the flow.

  On the other hand, when the temperature of the fuel cell stack 13 is lower than the predetermined temperature (step S12; No), the process proceeds to step S14. In step S <b> 14, the control computer 15 acquires the temperature of the compressed air 22 and the dew point temperature of the compressed air 22 described above. That is, the control computer 15 acquires the signal S <b> 2 from the temperature sensor 9 and acquires the signal S <b> 3 from the dew point temperature sensor 10. When the above process ends, the process proceeds to step S15.

  In step S15, the control computer 15 calculates the humidity of the compressed air 22 based on the temperature of the compressed air 22 and the dew point temperature acquired in step S14. Then, the process proceeds to step S16. When a humidity sensor or the like in which the temperature sensor and the dew point temperature sensor are integrated is used in the fuel cell air compression system 100, the control computer 15 can directly acquire a signal corresponding to the humidity.

  In step S <b> 16, the control computer 15 acquires the flow rate of the compressed air 21. That is, the control computer 15 acquires the signal S1 from the flow meter 3. Then, the process proceeds to step S17.

  In step S <b> 17, the control computer 15 calculates a value to increase or decrease a water injection amount. In step S <b> 17, the control computer 15 determines the increase / decrease value of the water to be injected into the compressed air 21 based on the acquired temperature of the compressed air 22, the humidity of the compressed air 22, and the flow rate of the compressed air 21. calculate. The reason why the increase / decrease value of the injection amount is calculated based on such parameters is to cool the compressed air 21 and to set it to an appropriate humidity according to the situation in the fuel cell stack 13. A specific calculation method will be described later. When the above process ends, the process proceeds to step S18.

  In step S18, the control computer 15 causes each injector to inject an injection amount after adding the increase value / decrease value calculated in step S17 (hereinafter, this injection amount is referred to as "actual injection amount"). Control. The control computer 15 can individually control the injection amount for each of a plurality of injectors based on the actual injection amount and the like. Moreover, only what was selected from the several injector can also be made to inject water. In such a case, the total value of the injection amounts injected from all the injectors is the actual injection amount. Furthermore, it is possible to inject the same injection amount from all of a plurality of injectors. In this case, an amount obtained by dividing the actual injection amount by the number of injectors is injected from one injector.

  When the process of step S18 is completed, the flow is exited. Then, the control computer 15 repeatedly executes the flow.

  As described above, by controlling the water supply amount based on the temperature, humidity, and flow rate of the compressed air, the compressed air is effectively cooled, and the fuel cell stack 13 is adjusted according to the state of the membrane. Appropriate humidity can be maintained. Thereby, deterioration of the fuel cell stack 13 can be prevented, and flooding and dryout of the fuel cell stack 13 can be prevented. Therefore, the utilization efficiency (power generation efficiency) of the fuel cell stack 13 can be improved.

  Next, the process in step S17 of the flowchart shown in FIG. 2, that is, the process of calculating the increase / decrease value of the water injection amount will be described in detail with reference to the flowchart shown in FIG. The process described below is also performed mainly by the control computer 15.

  First, in step S <b> 21, the control computer 15 calls a map indicating the relationship between the compressed air humidity and the output power of the fuel cell stack 13. Then, the process proceeds to step S22, and the control computer 15 determines the humidity (hereinafter referred to as “target humidity”) at which the compressed air is to be set based on this map.

  A specific example of the above map and a method for determining the target humidity will be described with reference to FIG. In the diagram shown in FIG. 4, the horizontal axis represents the current value of the fuel cell stack 13, and the vertical axis represents the relative humidity (% AH) and the voltage value. A curve X1 is a characteristic curve showing a general voltage-current relationship for the fuel cell stack 13. A curve X2 is an example of a characteristic curve showing the relationship between the relative humidity and the current value to be set in the fuel cell in order to maintain the output characteristic shown by the curve X1. This characteristic curve X2 is obtained by experiment and is stored in advance in a memory in the control computer 15 or the like.

  The control computer 15 acquires the current value required for the fuel cell stack 13, and determines the target humidity of the compressed air with reference to the map from the current value. For example, when the required current value is I1, the relative humidity h1 is the target humidity, and when the required current value is I2, the relative humidity h2 is the target humidity. The target humidity of compressed air is determined as described above. Then, the process proceeds to step S23.

  In step S23, the control computer 15 determines the temperature (target temperature) at which the compressed air is to be set based on the target humidity determined in step S22. The control computer 15 determines a target temperature corresponding to the target humidity with reference to a humidity conversion table indicating the relationship between temperature and humidity related to air (air). This humidity conversion table is also stored in the memory in the control computer 15. When the above process ends, the process proceeds to step S24.

  In step S24, the control computer 15 calculates an increase value or a decrease value of the injection amount based on the acquired data. Specifically, the control computer 15 calculates an increase value or a decrease value of the injection amount based on the following arithmetic expression (1).

Δm = M × Cv × ΔT / CL Formula (1)
Δm is an increase value or decrease value of the injection amount to be calculated, M is a flow rate of the compressed air (including air and water), Cv is a heat capacity of the compressed air (including air and water), ΔT is the difference between the current temperature of the compressed air and the target temperature, and CL indicates the specific heat of water (liquid).

  When the above process ends, the process exits the flow. Then, the process proceeds to step S18 in the flowchart shown in FIG. 2, and the control computer 15 performs the process described above. Repeating the process shown in FIG. 2 (including the process shown in FIG. 3) repeatedly corrects the humidity of the compressed air determined last time. Therefore, the humidity of the compressed air converges to a target humidity appropriate for the situation of the fuel cell stack 13.

[Configuration of Water Injection Unit 4]
Below, the Example which concerns on this invention regarding the structure of the water injection part 4 mentioned above is described using FIGS.

(First embodiment)
First, the configuration of the water injection unit 4 according to the first embodiment will be described. FIG. 5 is a diagram schematically illustrating a schematic configuration of the water injection unit 4 provided in the intake passage 2. As illustrated, injectors 5, 6, and 7 are provided on the outer wall surface of the intake passage 2 along the flow direction of the compressed air 21. The injectors 5, 6, and 7 inject thin screen-like water as indicated by reference numeral 40. Note that the fuel cell air compression system 100 according to the present embodiment uses an injector (hereinafter referred to as a meaning including all of the injectors 5, 6, and 7) when the compressed air 21 flows. Although there are a plurality (two or more) in the direction, only the injectors 5, 6 and 7 will be described here for convenience of description.

  A sectional view of the injectors 5, 6, 7 is shown in FIG. FIG. 6A is a view of the intake passage 2 and the injector 5 cut along the cutting line A1-A1 'in FIG. 6B is a view of the intake passage 2 and the injector 6 cut along the cutting line A2-A2 ′ in FIG. 5, and FIG. 6C is a view of the intake passage 2 and the injector 7 cut in FIG. It is the figure cut | disconnected along line A3-A3 '. As shown, the cross section of the intake passage 2 is substantially circular. The injectors 5, 6, and 7 are provided such that their center lines pass through the center point of the cross section of the intake passage 2. 6 (a) and 6 (b), the injector 5 and the injector 6 are provided on the circumference of the intake passage 2 at a position where the central angle is shifted by 120 °. Further, from FIG. 6B and FIG. 6C, the injector 6 and the injector 7 are provided on the circumference of the intake passage 2 at a position where the central angle is shifted by 120 °. In other words, the position of the injector on the circumference of the intake passage 2 is shifted according to the position in the flow direction provided (in the case of FIG. 6, the central angle is 120 °). Thus, adjacent injectors are not provided with overlapping circumferential positions of the intake passage 2.

  Water is injected from the tip of the injector at an injection angle θ. The water injected from the injector collides with the inner peripheral wall of the intake passage 2 and is reflected and diffused throughout the entire cross section of the intake passage 2. For example, water injected from the injector has a substantially hexagonal cross-sectional shape as indicated by reference numeral 40. Further, it is preferable that the injection angle θ is large. This is because the larger the injection angle θ, the wider the cross section of the intake passage 2 can be covered with water injected from the injector.

  In the configuration of the water injection unit 4 according to the first embodiment, since only one injector is provided in the direction perpendicular to the flow of the compressed air 21, a region indicated by reference numeral 40 (hereinafter referred to as “water injection”). In the area 40), the water density varies depending on the location. However, since a plurality of injectors are provided in the flow direction of the compressed air 21, and the circumferential position of the intake passage 2 where the injectors are provided is shifted, the compressed air 21 is injected into the water of the first injector. Even when the water density in the region 40 passes through a sparse part, the water jet region 40 of the next injector can pass through a dense part. Therefore, the compressed air 21 can come into contact with the uniformly diffused water in the entire water injection unit 4. Therefore, the water injection unit 4 can uniformly cool and adjust the humidity with respect to the compressed air 21.

  Furthermore, since the compressed air 21 is cooled by a plurality of injectors provided along the flow direction of the compressed air 21, no sudden temperature change occurs when the compressed air 21 is vaporized. This can prevent the intake passage 2 from deteriorating.

(Second embodiment)
Next, the configuration of the water injection unit 4 according to the second embodiment will be described. FIG. 7 is a diagram schematically illustrating a schematic configuration of the water injection unit 4 provided in the intake passage 2. Fig.7 (a) shows the side view of the water injection part 4 and the intake passage 2, and FIG.7 (b) shows the sectional drawing.

  7A, a plurality of injectors are provided in the direction perpendicular to the flow of the compressed air 21 (a plurality of injectors provided in the vertical direction are set as one set). A plurality of sets are also provided in the flow direction of the compressed air 21. Specifically, the injector 5a, the injector 5b, and the injector 5c are provided in a direction perpendicular to the flow of the compressed air 21. Next to this set, a set comprising an injector 6a, an injector 6b and an injector 6c is provided, and next to this set, a set comprising an injector 7a, an injector 7b and an injector 7c is provided. In the air compression system 100 for a fuel cell according to the present embodiment, a plurality of (two or more) injectors are provided in the flow direction of the compressed air 21, but for convenience of explanation, only the above three sets are provided. Give an explanation.

  FIG. 7B is a view of the injectors 5a, 5b, and 5c cut along the cutting line B1-B1 '. The views of the injectors 6a, 6b, 6c cut along the cutting line B2-B2 'and the views of the injectors 7a, 7b, 7c cut along the cutting line B3-B3' are those of the injectors 5a, 5b, 5c. Since they are the same as those shown in FIG. As illustrated, the injectors 5a, 5b, and 5c, the injectors 6a, 6b, and 6c, and the injectors 7a, 7b, and 7c are provided on the outer peripheral wall of the intake passage 2 at equal intervals of a central angle of 120 °. Then, water is injected at an injection angle θ.

  In the configuration of the water injection unit 4 according to the first example, only one is provided in the direction perpendicular to the flow of the compressed air 21, and therefore, in the water injection region 40, the water density varies depending on the location. However, in the configuration of the injector according to the second embodiment, since a plurality of injectors are provided in the direction perpendicular to the flow of the compressed air 21, the injected water diffuses almost evenly in the surface of the water injection region 40. become. Therefore, the cooling effect of the compressed air 21 by the water injected from the injector and the accuracy of humidity adjustment for the compressed air 21 can be increased. In addition, since three injectors are provided in the direction perpendicular to the flow of the compressed air 21, detailed control regarding the water injection amount and the like can be performed.

(Third embodiment)
Next, the configuration of the water injection unit 4 according to the third embodiment will be described. In the third embodiment, as in the second embodiment, a plurality of injectors are provided in the direction perpendicular to the flow of the compressed air 21 (this is one set), and a plurality of sets are also provided in the flow direction. It has been. However, in the third embodiment, the circumferential position of the intake passage 2 where the injector set is provided is shifted according to the flow direction of the compressed air 21.

  FIG. 8 is a view of the injector according to the third embodiment cut along the cutting line in FIG. FIG. 8A is a view of the injectors 5a, 5b, and 5c cut along the cutting line B1-B1 'in FIG. 7A. 8B is a view of the injectors 6a, 6b, and 6c cut along the cutting line B2-B2 ′ in FIG. 7A, and FIG. 8C is a view of the injectors 7a, 7b, and 7c. It is the figure cut | disconnected along cut line B3-B3 'in 7 (a). FIG. 8 shows that the positions on the circumference of the intake passage 2 where the injectors are provided do not overlap in adjacent sets.

  By disposing the injector as described above, the water injection region 40 is also displaced along with the displacement of the arrangement position of the injector in the flow direction. Therefore, even when the compressed air 21 does not pass through the water injection region 40 by the first injector set, it can pass through the water injection region 40 by the next injector set. Thereby, the cooling effect of the compressed air 21 by the water injection unit 4 and the accuracy of humidity adjustment for the compressed air 21 can be further increased.

  In the second and third embodiments, three injectors are provided in the direction perpendicular to the flow of the compressed air 21, but the number is not limited. Two injectors may be provided, or four or more injectors may be provided.

It is a block diagram which shows schematic structure of the air compression system for fuel cells which concerns on embodiment of this invention. It is a flowchart which shows the water supply amount control process which concerns on embodiment of this invention. It is a flowchart which shows the injection amount calculation process of step S17 of FIG. It is a figure which shows the relationship between the relative humidity of a fuel cell stack, and an output. It is a figure which shows schematic structure of the water injection part which concerns on 1st Example of this invention. Sectional drawing, such as an injector along the cutting line of FIG. 5, is shown. It is a figure which shows schematic structure of the water injection part which concerns on 2nd Example of this invention, and sectional drawings, such as an injector. It is a figure which shows sectional drawing, such as an injector which concerns on 3rd Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Compressor 2 Intake passage 3 Flowmeter 9,11 Temperature sensor 10 Dew point temperature sensor 4 Water injection part 5a, 5b, 6b, 6c Injector 12a Cathode pole 12b Anode pole 13 Fuel cell stack 15 Control computer 100 Fuel cell air compression system

Claims (7)

Air compression means for compressing air supplied to the fuel cell stack;
Water supply means for supplying the compressed air by spraying water;
Temperature acquisition means for acquiring the temperature of the compressed air;
Humidity acquisition means for acquiring the humidity of the compressed air;
An air compression system for a fuel cell, comprising: a water supply amount control unit configured to control the amount of water to be supplied based on the acquired temperature and the acquired humidity. 2. The fuel cell air compression system according to claim 1, wherein the water supply amount control unit controls the amount of water to be supplied so that the acquired humidity becomes a target humidity. 3. A flow rate acquisition means for acquiring the flow rate of the compressed air;
3. The fuel cell air compression system according to claim 1, wherein the water supply amount control means controls the amount of water to be supplied based on a flow rate of the compressed air. A fuel cell stack temperature acquisition means for acquiring the temperature of the fuel cell stack;
The water supply amount control means increases the amount of water to be supplied when the temperature of the acquired fuel cell stack is equal to or higher than a predetermined temperature. An air compression system for a fuel cell as described in 1. 5. The fuel cell air compression system according to claim 1, wherein a plurality of the water supply units are provided in a flow direction of the compressed air. 6. The air compression system for a fuel cell according to any one of claims 1 to 5, wherein a plurality of the water supply means are provided in a direction perpendicular to the flow of the compressed air. The fuel cell air compression system according to any one of claims 1 to 6, wherein the temperature acquisition unit and the humidity acquisition unit are provided downstream of the water supply unit.

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