JP2010177123A - Fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve a measuring accuracy of a supply volume of oxidant gas to a fuel cell. <P>SOLUTION: The fuel cell is provided with a fuel cell housed in a case, and an oxidant gas supply-exhaust system having a supply passage of oxidant gas to the fuel cell, an exhausting passage of oxidant exhaust gas to be exhausted from the fuel cell, and a bypass passage circulating the oxidant exhaust gas from the exhausting passage to the supply passage as oxidant gas. In the oxidant gas supply-exhaust system, a gas flowmeter is installed in the supply passage at a downstream side further than the jointing position with the bypass passage and still at a part inside the case. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a technique for improving the measurement accuracy of the amount of oxidant gas supplied to a fuel cell.

  In general, for example, a fuel cell generates electricity by causing an electrochemical reaction between air used as an oxidizing gas and hydrogen as a fuel gas. When developing a fuel cell system using this fuel cell, for example, an automobile called a fuel cell vehicle, it is developed based on an automobile using an internal combustion engine (engine) (hereinafter referred to as an “engine vehicle”). It is common to do this.

  In a conventional engine vehicle, an air flow meter (hereinafter also abbreviated as “AFM”) for measuring the supply amount of air used for burning fuel is set in an air cleaner provided near the air intake port. It is common.

  However, in a fuel cell system such as a fuel cell vehicle, air as an oxidizing gas output from an air cleaner is supplied to the fuel cell through the exhaust gas flow from the fuel cell. There may be a bypass flow path for circulation. For this reason, a part of the flow rate of the oxidizing gas output from the air cleaner leaks through the bypass flow path, and the supply amount of the oxidizing gas actually supplied to the fuel cell may be smaller than the flow rate measured by the flow meter. There is sex.

  Therefore, in order to improve the power generation performance in the fuel cell, it is desirable to ensure the necessary and sufficient oxidation gas and fuel gas stoichiometry, so the measured flow rate is larger than the set supply amount, and the actual supply amount to the fuel cell It is required to adjust the compressor so that becomes the set flow rate. As a result, there arises a problem that the fuel utilization efficiency of the fuel cell system is lowered.

JP 2002-110213 A JP 2008-218170 A JP 2002-362164 A JP 2006-216479 A JP 2006-216479 A

  Therefore, an object of the present invention is to provide a technique capable of improving the measurement accuracy of the amount of oxidant gas supplied to the fuel cell in the fuel cell system.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

[Application Example 1]
A fuel cell system,
A fuel cell housed in a case;
The oxidation gas supply flow path connected to the oxidation gas supply port of the fuel cell, the oxidation exhaust gas discharge flow path connected to the oxidation exhaust gas discharge port of the fuel cell, and the oxidation exhaust gas to the oxidation An oxidant gas supply / discharge system having a bypass flow path for refluxing from the discharge flow path to the supply flow path as a gas;
With
The oxidant gas supply / exhaust system is characterized in that a gas flow meter is installed in a part of the supply channel downstream of the merging position of the bypass channel and in the case. Fuel cell system.
In this fuel cell system, since the gas flow meter is installed in the vicinity of the oxidizing gas supply port of the fuel cell, the measurement accuracy of the supply amount of the oxidizing gas supplied to the fuel cell can be improved. In addition, since the flow meter is provided in the case containing the fuel cell, for example, when the fuel cell system is applied to a fuel cell vehicle, in the structure in which the fuel cell is mounted under the vehicle floor, the gas flow rate When the meter is not housed in the case, a gas flow meter with a waterproof function is required, but a gas flow meter without a waterproof function can be used, so there is a cost reduction effect. .

  The present invention can be realized in various forms, for example, in various forms such as a fuel cell system and a fuel cell.

It is a block diagram which shows schematic structure of the part of the supply / exhaust system of the oxidizing gas mainly of the fuel cell system as an Example.

  FIG. 1 is a block diagram showing a schematic configuration of a main part of an oxidizing gas supply / discharge system of a fuel cell system as an embodiment. The fuel cell system 10 includes a fuel cell 100 and an oxidizing gas supply / discharge system 200.

  The fuel cell 100 is an electric power between a fuel gas (hydrogen) as an anode gas supplied to an anode (not shown) and an oxidizing gas (air, more specifically, oxygen contained in air) as a cathode gas supplied to a cathode. Electricity is generated by chemical reaction. As this fuel cell 100, various fuel cells such as a polymer electrolyte fuel cell can be used. In general, the fuel cell 100 has a stack structure in which a plurality of fuel cells are stacked.

  The oxidizing gas supply / discharge system 200 includes an oxidizing gas supply pipe 210 serving as an oxidizing gas supply channel connected to the oxidizing gas supply port 102 of the fuel cell 100 and an oxidizing gas connected to the oxidizing exhaust gas discharge port 104 of the fuel cell 100. An oxidation exhaust gas discharge pipe 220 as an exhaust gas discharge flow path, and a bypass pipe 230 as a bypass flow path for returning the oxidation exhaust gas as an oxidation gas from the oxidation exhaust gas discharge pipe 220 to the oxidation gas supply pipe 210 are provided.

  The oxidizing gas supply pipe 210 is provided with an air cleaner 212 and an air compressor (ACP) 214 in a portion from the intake port to the joining position G1 with the bypass pipe 230. Further, an air flow meter (AFM) 216 is provided in the vicinity of the oxidizing gas supply port 102 downstream of the merging position G1.

  The oxidation exhaust gas discharge pipe 220 is provided with a muffler 222 in a portion from the joining position G1 with the bypass pipe 230 to the exhaust port. Further, a discharge valve 224 for controlling the discharge of the oxidation exhaust gas is provided in the vicinity of the oxidation exhaust gas discharge port 104 upstream of the joining position G2. Oxidation exhaust gas and generated water are discharged by opening and closing the discharge valve 224. As the discharge valve 224, for example, an electromagnetic valve is used.

  The bypass pipe 230 is provided with a circulation control valve 232 that controls the circulation of the oxidizing exhaust gas. The circulation of the oxidation exhaust gas is turned on / off by opening / closing the circulation control valve 232. As the circulation control valve 232, for example, an electromagnetic valve is used.

  As described above, by providing the air flow meter 216 in the vicinity of the oxidizing gas supply port 102 of the fuel cell 100, the measurement accuracy of the oxidizing gas supplied to the fuel cell 100 can be improved.

  Further, for example, assuming that the fuel cell 100 is mounted on a fuel cell vehicle, the fuel cell 100 is highly likely to be installed under the floor of the vehicle. For this reason, it is preferable to waterproof to prevent getting wet. Therefore, the fuel cell 100 of the present embodiment is stored in a storage case 300 having a waterproof function. Similarly, an air flow meter 216 provided in the vicinity of the oxidizing gas supply port 102 of the fuel cell 100 is also stored in the storage case 300. Thereby, as a component used as the air flow meter 216, a standard component having no waterproof function can be used, which is advantageous for cost reduction.

  In addition, in order to improve waterproofness of various valves, such as the discharge valve 224, it is good also as a structure accommodated in the storage case 300. FIG.

  In addition, elements other than the elements claimed in the independent claims among the constituent elements in each of the above embodiments are additional elements and can be omitted as appropriate. The present invention is not limited to the above-described examples and embodiments, and can be implemented in various modes without departing from the scope of the invention.

DESCRIPTION OF SYMBOLS 10 ... Fuel cell system 30 ... Storage case 100 ... Fuel cell 102 ... Oxidation gas supply port 104 ... Oxidation exhaust gas discharge port 200 ... Oxidation gas supply / discharge system 210 ... Oxidation gas supply piping 212 ... Air cleaner 216 ... Air flow meter 220 ... Oxidation exhaust gas discharge Piping 222 ... Muffler 224 ... Discharge valve 230 ... Bypass piping 232 ... Circulation control valve 300 ... Storage case G1 ... Junction position G2 ... Junction position

Claims (1)

A fuel cell system,
A fuel cell housed in a case;
A supply flow path for oxidizing gas to the fuel cell, a discharge flow path for oxidizing exhaust gas discharged from the fuel cell, and a bypass flow for returning the oxidizing exhaust gas as the oxidizing gas from the discharge flow path to the supply flow path An oxidizing gas supply / exhaust system having a path;
With
The oxidant gas supply / exhaust system is characterized in that a gas flow meter is installed in a part of the supply channel downstream of the merging position of the bypass channel and in the case. Fuel cell system.

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