JP2007173170A - Fuel cell system - Google Patents

Abstract

To improve detection accuracy by optimizing the arrangement of a pressure detector and a temperature detector.
In a fuel cell system for generating power by supplying air and fuel to a fuel cell body, two or more pressure sensors 22 and 23 and a temperature are respectively provided in a gas flow path (pipe 1) through which air and / or fuel flows. Sensors 24 and 25 are provided. The pressure sensors 22 and 23 are arranged side by side in a direction A substantially parallel to the gas flow direction, and the temperature sensors 24 and 25 are arranged in the same cross section substantially orthogonal to the gas flow direction. A heater 26 is provided in the vicinity of the pressure sensors 22 and 23, and temperature sensors 24 and 25 are provided in the vicinity of the heater, and an abnormality of the heater 26 is detected from temperature information of two or more sensors.
[Selection] Figure 1

Description

  The present invention relates to a fuel cell system that generates air by supplying air and fuel to a fuel cell body, and more particularly to a fuel cell system that is applied for in-vehicle use.

For example, as described in Patent Document 1 and Patent Document 2, conventional fuel cell systems maintain the optimum state by detecting the state of air, fuel, exhaust gas, or the like supplied to the fuel cell body with a sensor. It is controlled to do.
JP 2000-243418 A JP-A-2005-93110

  However, in Patent Documents 1 and 2, although it is recognized that information on pressure and temperature is important in operating the fuel cell system, its mounting and arrangement are not clarified. The liquid water unique to the fuel cell system may adversely affect pressure detection and temperature detection.

  Specifically, when the environmental temperature is low, moisture in the system may condense and flow in the system in a mixed phase of gas phase and liquid phase, which may cause an error in pressure detection in particular. . In addition, when the ambient temperature drops below zero and the condensed liquid water freezes, the detection error may be further increased.

  Accordingly, the present invention has two or more pressure and temperature detectors and optimizes the arrangement of the pressure detector and the temperature detector to improve detection accuracy and enable stable operation. The purpose is to provide a system.

  The fuel cell system of the present invention includes at least two pressure detectors and temperature detectors for detecting the pressure and temperature of the gas to be measured in the gas flow path through which air and / or fuel flows.

  In this fuel cell system, the pressure detector is arranged in the gas flow path in a direction substantially parallel to the direction in which the gas to be measured flows, while the temperature detector is disposed in the gas flow path in the gas to be measured. Are arranged side by side in the same cross section substantially perpendicular to the flowing direction.

  According to the present invention, the state of the gas (air and fuel) flowing through the system, that is, the pressure and temperature of the gas are more accurately determined by two or more pressure detectors and temperature detectors, respectively. Can be detected.

  Hereinafter, specific embodiments to which the present invention is applied will be described in detail with reference to the drawings.

  1A is a longitudinal sectional view showing the main part of the present embodiment, FIG. 1B is a cross-sectional view taken along the arrow Ib-Ib of FIG. 1A, and FIG. 2 is an external perspective view of the main part of the present embodiment. FIG. 3 is a system configuration diagram showing an outline of the present embodiment.

  First, the basic configuration of the fuel cell system will be described with reference to FIG. The fuel cell main body 10 which is the main body of the system has catalyst electrode layers 12a and 13a in which a catalyst and a gas diffusion electrode are formed on both surfaces of an electrolyte membrane 11 in close contact, one of which is an oxidizing gas electrode 12 and the other is a fuel. The electrode 13 is an electrode, and by supplying air 20 as an oxidant gas and hydrogen 30 as a fuel gas to the respective electrode sides of the fuel cell main body 10, electricity generated between the two electrodes can be converted into external electricity. The power is taken out to the load 40 as electric power.

  Here, humidifiers 21 and 31 are attached to a line 1 (gas flow path) for supplying air 20 and a line (gas flow path) for supplying hydrogen 30, respectively, and the electrolyte membrane 11 in the fuel cell body 10 is attached. A wet state can be secured.

  Further, two pressure sensors (pressure detectors) 22 and 23 and two temperature sensors (temperature detectors) 24 and 25 are provided on the line for supplying the air 20. Similarly, two pressure sensors (pressure detectors) 32 and 33 and two temperature sensors (temperature detectors) 34 and 35 are provided on the line for supplying hydrogen 30.

  1 and 2 show examples of mounting and arrangement of pressure sensors 22 and 23 and temperature sensors 24 and 25 in a line for supplying air 20, for example. The same applies to the hydrogen side line, but only the air side line will be described here as a representative. Note that the illustrated example is exaggerated for easy understanding of the configuration and operation, and does not necessarily represent an actual dimensional relationship.

  1 and 2, reference numeral 1 indicates a pipe (gas flow path) constituting an air line, and 1a indicates a pipe inner wall. One of the pipes 1 communicates with an air compressor (not shown), and the other communicates with an oxidizing gas electrode 12 in the fuel cell main body 10. Therefore, the air sent from the compressor passes through the pipe 1 and is supplied to the fuel cell main body 10.

  Here, two pressure sensors 22 and 23 are parallel to the flow direction A of the gas (air to be measured) on the pipe wall (flow path wall) of the straight portion arranged in the substantially horizontal direction of the pipe 1. The port portions 22a and 23a of both pressure sensors 22 and 23 open in the same manner to the pipe inner wall 1a. In other words, the two pressure sensors 22 and 23 are arranged adjacent to a straight portion of the pipe 1 arranged in the horizontal direction so as to approach each other along the air flow direction A. , 23 are provided so that the port portions 22a, 23a face the gas flow path.

  Further, in the vicinity of the pressure sensor 22, two temperature sensors 24, 25 are substantially orthogonal to the flow direction A of the gas (measured gas) (substantially perpendicular to the pipe wall (flow path wall) of the pipe 1. Are arranged side by side in the same cross section. In other words, the two temperature sensors 24 and 25 are arranged side by side on an arbitrary cross section of the pipe 1 orthogonal to the gas flow direction A.

  In this case, the pressure sensor 22 located on the upstream side in the gas flow direction and the two temperature sensors 24 and 25 are arranged in the same cross section. That is, if the horizontal center line intersecting with each other at the center of the pipe 1 is an X-ray and the vertical center line is a Y-line, the two temperature sensors 24 are included in the same cross section (Xb-Ib cross section) including the X-ray and the Y-line 25 and one pressure sensor 22 are arranged.

  One of the two pressure sensors 22 and 23 is set for system control, and the other is set for sensor diagnosis.

  In this case, since the diagnosis is based on the premise that the pressure is the same, the two pressure sensors 22 and 23 are always at positions where the pressure is the same (in a wide range from a small flow to a large flow even during steady operation). It is necessary to arrange. If the pressure medium is a gas phase, there is little problem even if the arrangement of the two pressure sensors 22 and 23 is not particularly concerned, but in the case of a gas-liquid mixed phase flow, the two pressure sensors 22 and 23 It is necessary to increase the identity of the 23 arrangements.

  Therefore, the two pressure sensors 22 and 23 are arranged side by side in a direction parallel to the gas flow direction. Moreover, the two pressure sensors 22 and 23 are attached above the horizontal center line X passing through the center of the pipe 1. This mounting position is preferably set in a range of an angle θ = 45 ° to 135 ° with respect to the horizontal center line X as shown in FIG. This is in consideration of the posture when mounted on a vehicle.

  On the other hand, the first temperature sensor 24 is provided on the horizontal center line X in the vicinity of the upstream pressure sensor 22, and the second temperature sensor 24 is located below the first temperature sensor 24. It is provided on the vertical center line Y of the pipe 1 passing through the center. That is, the two temperature sensors 24 and 25 are disposed in a positional relationship orthogonal to each other as an angle forming 90 degrees.

  In the present embodiment, a heater 26 is provided at a position adjacent to the upstream pressure sensor 22. The heater 26 is provided for preventing the pressure sensors 22 and 23 from freezing or for thawing after freezing. Since the pressure sensors 22 and 23 may cause a detection error when freezing occurs in the detection unit, the heater 26 is operated under an environment of zero.

  The detection values of the temperature sensors 24 and 25 after the heater 26 is turned on rise with a delay time according to the distance from the heater 26. That is, after the heater 26 is turned on, the heat of the heater 26 is transferred through the pipe 1 and firstly increases the detection value of the temperature sensor 24 located near the heater 26. Next, the detection value of the temperature sensor 25 located far from the heater 26 is increased with a slight delay.

  It can be determined that such a time lag in the rise in the detection values of the two temperature sensors 24, 25 is due to the heating of the heater 26. Therefore, conversely, it is possible to make a determination as to whether or not the heater 26 is operating normally by utilizing such a phenomenon of time deviation of the detection values of the temperature sensors 24 and 25.

  That is, when the fuel cell system is activated, the detection values of the temperature sensors 24 and 25 are increased due to the influence of elements other than the heater 26. There is almost no. On the other hand, in the case of the influence of heating by the heater 26, a time lag within the predicted range appears.

  Therefore, it is possible to determine whether or not the influence is due to the heater 26 by monitoring the time difference. That is, after the heater 26 is turned on, if the detection values of the temperature sensors 24 and 25 rise with a certain time lag, it can be determined that the heater 26 is functioning normally. It is.

  According to the present embodiment, the state of the gas (air and fuel) flowing through the system, that is, the pressure and temperature of the gas are determined by the two pressure sensors 22 and 23 and the temperature sensors 24 and 25, respectively. Can be detected.

  For example, for the detection of pressure that is easily affected by the gas flow, since two or more pressure sensors 22 and 23 are arranged in a position where the influence of the flow is the same from a small flow rate to a large flow rate, information on them is provided. By making the determination based on the detection error, the detection error can be reduced as much as possible. Moreover, since one is used for control and the other is used for diagnosis, the reliability of the detected value can be improved.

  If the two pressure sensors 22 and 23 are arranged apart from each other in the same cross section orthogonal to the gas flow direction like the temperature sensors 24 and 25, the detection error is caused by the influence of the gas flow. Will occur. This is due to non-uniformity in the cross section of the gas flow. In particular, in a low temperature environment, the gas phase and the liquid phase become a mixed phase flow, and the liquid phase component increases and the influence of gravity becomes stronger as the temperature decreases. In such a case, if they are formed in the same cross section, the ground mounting angle will inevitably differ, and the pressure detection difference due to the non-uniform flow field will increase.

  In addition, regarding temperature detection, there is a condition that a temperature difference tends to occur in the gas flow direction. However, since two temperature sensors 24 and 25 are arranged in the same cross section orthogonal to the gas flow direction, By making the determination based on the above information, the detection error can be reduced as much as possible without being affected by the temperature difference generated in the gas flow direction.

If the temperature sensors 24 and 25 are arranged in a direction parallel to the gas flow direction in the same manner as the pressure sensors 22 and 23, the detection error is affected by the temperature difference generated in the gas flow direction. Will occur. This is because a temperature gradient occurs in the flow direction.

  Further, since the two temperature sensors 24 and 25 are arranged in the same cross section as the arbitrary pressure sensor 22, the pressure and temperature on the same cross section of the gas flow can be known. The gas supply state of the fuel cell 10 can be correctly grasped on the same flow cross section, and as a result, the fuel cell main body 10 is mainly in a transitional state (for example, a transitional state is, for example, from low load operation such as idle to full accelerator opening. Changing suddenly or slowly during high-load operation is also called transient, because the present invention is more effective at sudden changes, because pressure and temperature changes can be accurately detected. The operation controllability (especially the temperature detection delay is small) can be improved. Further, the reliability of the fuel cell system can be improved by optimizing the arrangement of the pressure sensors 22 and 23 and the temperature sensors 24 and 25 in this way.

  As described above, in the fuel cell system according to the present embodiment, the fuel cell system 10 generates electricity by supplying air and fuel to the fuel cell main body 10, and the gas flow path (pipe 1) through which air and / or fuel flows is provided. The pressure sensors 22, 23, 32, 33 and the temperature sensors 24, 25, 34, 35 for detecting their pressure and temperature are provided at least two, respectively. The pipes 1 are arranged side by side in a direction substantially parallel to the direction A of the gas to be measured, and the temperature sensors 24, 25, 34, and 35 are identical to the pipe 1 and substantially perpendicular to the direction of the gas to be measured. Since they are arranged side by side in the cross section, the detection error can be reduced as much as possible, and the reliability of the fuel cell system can be improved.

  Further, according to the fuel cell system of the present embodiment, the temperature sensors 24, 25, 34, and 35 are arranged in the same cross section as the arbitrary pressure sensors 22 and 32, so that the gas supply state is correctly set on the same flow cross section. I can grasp it.

  Further, according to the fuel cell system of the present embodiment, since the two pressure sensors 22 and 23 are arranged on the same side and at the same angle with respect to the gas flow, detection errors detected by the pressure sensors 22 and 23 are detected. Can be further reduced.

  Further, according to the fuel cell system of the present embodiment, the heater 26 is provided in the vicinity of the pressure sensors 22, 23, 32, 33, and at least two temperature sensors 24, 25, 34, 35, and the abnormality of the heater 26 is detected from two or more temperature information obtained from the two or more temperature sensors 24, 25, 34, 35, thereby further improving the reliability of the system. Can do.

  Further, according to the fuel cell system of the present embodiment, the pressure sensors 22, 23, 32, 33 and the temperature sensors 24, 25, 34, 35 are arranged in a flow of the straight pipe 1 arranged in a substantially horizontal direction. Since the pressure sensors 22, 23, 32, and 33 are provided on the road wall and are disposed above the center line (horizontal center line X) of the pipe 1, the pressure detection accuracy can be increased. In particular, in the case of a gas-liquid mixed phase flow, pressure fluctuation due to the ingress of liquid water can be reduced.

  Although specific embodiments to which the present invention is applied have been described above, the above-described embodiments are examples of the present invention and are not limited to these embodiments.

  In the above embodiment, two pressure sensors 22, 23, 32, and 33 and two temperature sensors 24, 25, 34, and 35 are provided. However, three or more of these may be provided. .

Fig.1 (a) is a longitudinal cross-sectional view which shows the principal part of this embodiment, FIG.1 (b) is Ib-Ib arrow sectional drawing of (a). It is an external appearance perspective view of the principal part of this embodiment. It is a system configuration figure showing the outline of this embodiment.

Explanation of symbols

1 ... Piping (gas flow path)
10 ... Fuel cell body 22, 23 ... Pressure sensor (pressure detector)
24, 25 ... Temperature sensor (temperature detector)
26… Heater

Claims (5)

In a fuel cell system for generating electricity by supplying air and fuel to the fuel cell body,
At least two or more pressure detectors and temperature detectors for detecting the pressure and temperature of the gas to be measured are provided in the gas flow path through which the air and / or fuel flows,
The pressure detector is arranged in the gas flow path in a direction substantially parallel to the direction in which the measurement gas flows,
The temperature detector is arranged in the gas flow path side by side in the same cross section substantially perpendicular to the flow direction of the gas to be measured. The fuel cell system according to claim 1,
Two or more temperature detectors are arranged in the same cross section as at least one of the pressure detectors. A fuel cell system. The fuel cell system according to claim 1 or 2, wherein
Two or more pressure detectors are arranged on the same side and at the same angle with respect to the flow of the gas to be measured. A fuel cell system. A fuel cell system according to any one of claims 1 to 3,
With a heater in the vicinity of the pressure detector,
Comprising at least two or more temperature detectors in the vicinity of the heater;
An abnormality of the heater is detected from two or more pieces of temperature information obtained from the two or more temperature detectors. A fuel cell system according to any one of claims 1 to 4, comprising:
The pressure detector and the temperature detector are mounted on a straight flow path wall of the gas flow path disposed in a substantially horizontal direction, and the pressure detector is disposed above the center line of the gas flow path. A fuel cell system characterized by that.

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