JP2008235051A - Gas-liquid separator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gas-liquid separator capable of carrying out drainage appropriately without detecting a water level in a tank, and controlling timing to carry out discharge of formed water by only one sensor. <P>SOLUTION: This is the gas-liquid separator A to separate water mixed in an anode off gas from a fuel cell stack 10 from the anode off gas, and equipped with a tank to separate water from the anode off gas, a drain valve 26 to discharge water from the tank 25, a piping P7 to connect the tank 25 and the drain valve 26, a water detection sensor 29 which is installed at the piping P7 on the upstream side of the drain valve 26 and detects with or without of water, and ECU 51 to control a discharge amount of water in the drain valve 26 based on a detecting signal from the water detection sensor 29. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a gas-liquid separator used in a fuel cell system.

  A gas-liquid separation device used in a fuel cell system separates water (product water) by-produced when the fuel cell generates an electromotive force by an electrochemical reaction between hydrogen and oxygen. This generated water is discharged from the fuel cell together with the offgas. Since this generated water may obstruct the flow of fuel gas (oxygen and hydrogen) in the fuel cell system, it is separated from off-gas by a predetermined gas-liquid separator.

Conventionally, as a gas-liquid separation device, one provided in a pipe for circulating off-gas from a fuel cell is known. A tank for storing separated generated water, a pipe for draining the generated water from the tank, What is provided with the drain valve provided in piping is known (for example, refer patent document 1). The gas-liquid separation device includes water level detection sensors above and below the tank. The upper water level detection sensor is disposed at a position for detecting the upper limit water level of the tank, and the lower water level detection sensor is The tank is disposed at a position where the lower limit water level is detected.
In such a gas-liquid separator, the upper water level detection sensor is used as a sensor for determining the timing for starting drainage from the tank, and the lower water level detection sensor is used for determining the timing for ending drainage from the tank. in use.
JP 2005-50554 A

  However, in the conventional gas-liquid separator (see, for example, Patent Document 1), the timing for starting drainage from the storage tank and the timing for ending the drainage are determined by detecting the water level in the tank. Such a problem may occur.

  First, when this gas-liquid separator is used in a fuel cell system mounted on a vehicle or the like, the water level in the storage tank fluctuates when the vehicle or the like tilts or when the vehicle or the like accelerates or decelerates. As a result, this gas-liquid separator has a problem that the drainage and the timing of its termination may not be accurately determined, and its reliability is not sufficient.

  Also, in the conventional gas-liquid separator, the timing to start draining from the tank is determined by the water detected by the upper water level detection sensor. Water may have accumulated. On the other hand, when the amount of power generated by the fuel cell increases rapidly, the amount of by-produced water also increases abruptly. When the generated water is stored up to the upper limit in the tank, if the amount of generated water increases rapidly, the waste water from the tank may not catch up and the generated water may overflow from the storage tank. That is, this gas-liquid separation device may cause overflow of produced water, resulting in a problem that the water replenishment capability is reduced.

  In addition, in the conventional gas-liquid separator, the timing for ending drainage from the tank is determined by detecting water by the lower water level detection sensor, so that the generated water in the tank is close to the lower limit even in steady state. It may be less. On the other hand, as described above, since the water level fluctuates in a vehicle or the like, drainage may continue even if the water level in the tank is lower than the lower limit water level. As a result, in this gas-liquid separator, off-gas such as hydrogen may be discharged out of the fuel system through the tank following drainage, especially in a fuel system that circulates and uses unreacted hydrogen in the off-gas. There is a problem that the utilization efficiency of fuel gas is lowered.

  Further, in the conventional gas-liquid separator, it is conceivable to enlarge the tank in order to prevent the overflow of the generated water and the off-gas such as hydrogen being discharged out of the fuel system. However, this leads to an increase in size and weight of the gas-liquid separator.

In addition, since the conventional gas-liquid separation device includes two water level detection sensors provided in the tank, there is a problem that the control of these sensors becomes complicated and the manufacturing cost of the gas-liquid separation device itself increases. is there.
As described above, in the conventional gas-liquid separator, the water can be drained accurately without detecting the water level in the tank, and the timing at which the generated water is discharged can be controlled by only one sensor. A liquid separator was desired.

  Accordingly, an object of the present invention is to provide a gas-liquid separation device that can accurately drain water without detecting the water level in the tank, and can control the timing of discharging generated water with only one sensor. There is to do.

The invention for solving the above-mentioned problems is a gas-liquid separation device for separating a liquid mixed in a gas from a fuel cell from the gas, the tank separating the liquid from the gas, and the liquid from the tank. A drain mechanism for discharging, a discharge pipe portion connecting the tank and the drain mechanism, and a liquid detection means provided on the discharge pipe portion on the upstream side of the drain mechanism to detect the presence or absence of the liquid; Control means for controlling the discharge amount of the liquid in the drain mechanism based on a detection signal from the liquid detection means.
In this gas-liquid separator, unlike the conventional gas-liquid separator (see, for example, Patent Document 1), the detection of water is not based on the water level in the tank, but on the basis of whether water is present in the discharge pipe or not. Since the timing and the timing of the end of drainage are determined, it is not necessary to detect the water level in the tank. As a result, the gas-liquid separation device of the present invention can perform drainage accurately even if the water level fluctuates due to the inclination of the gas-liquid separation device.
Further, in this gas-liquid separator, the timing of drainage and the timing of termination of the drainage are determined depending on whether or not water is present in the discharge pipe portion, so the timing is controlled by one liquid detection means. be able to.

  In such a gas-liquid separator, the drain mechanism is a drain valve, and the control means opens the drain valve when it is determined by the detection signal that the liquid is present. It may be configured to be controlled.

  Further, in such a gas-liquid separation device, the drain mechanism is a drain valve, and the control means closes the drain valve when it is determined by the detection signal that the liquid is not present. It may be configured to control so as to.

  In such a gas-liquid separator, the capacity of the discharge pipe section from the liquid detection means to the drain mechanism is determined after the liquid detection means detects that the liquid is not present. It is desirable that the volume in which the gas in the discharge pipe portion does not reach the drain mechanism in response time until the mechanism operates.

  In such a gas-liquid separation device, the capacity of the discharge pipe section from the liquid detection means to the drain mechanism is such that the flow rate of the gas from the fuel cell is maximized. When it is detected that the liquid does not exist continuously until the time when the presence / absence of the liquid is determined is passed, the gas in the discharge pipe portion reaches the drain mechanism at the time. It is desirable that the volume is not set.

  Further, in such a gas-liquid separator, the capacity of the discharge pipe part from the connection part between the tank and the discharge pipe part to the liquid detection means is such that the flow rate of the gas from the fuel cell is maximum. When it is detected that the liquid is continuously present until the time until the presence or absence of the liquid is determined by the liquid detection means elapses. It is desirable that the volume of the liquid flowing into the discharge pipe portion from the inside does not reach the connection portion.

  Further, in such a gas-liquid separator, the drain mechanism is a drain valve, and the control means until the time when the presence or absence of the liquid is determined by the liquid detection means has elapsed. The drain valve can be prohibited from being opened.

  According to the gas-liquid separator of the present invention, water can be drained accurately without detecting the water level in the tank, and the timing at which the generated water is discharged can be controlled with only one sensor.

  Hereinafter, an embodiment of the gas-liquid separator of the present invention will be described in detail with reference to the drawings as appropriate. In the drawings to be referred to, FIG. 1 is an overall configuration diagram of a fuel cell system using the gas-liquid separation device of the present embodiment. FIG. 2 is a schematic diagram for explaining the configuration of the gas-liquid separation device of the present embodiment. Here, after first describing the fuel cell system using the gas-liquid separator of the present embodiment, the gas-liquid separator will be described.

  As shown in FIG. 1, the fuel cell system 1 according to this embodiment includes a fuel cell stack 10, an anode system 20, a cathode system 30, a dilution system 40, a control system 50, and the like.

  As is well known, the fuel cell stack 10 includes an electrolyte membrane 11 made of a solid polymer sandwiched between an anode 12 containing a catalyst and a cathode 13 containing a catalyst, and further sandwiched between a pair of conductive separators 14 and 15. Although it has the comprised single cell, although not shown in figure, it is comprised by laminating | stacking multiple this single cell in the thickness direction. In the fuel cell stack 10, as will be described later, an electromotive force is generated by an electrochemical reaction between hydrogen (hydrogen) supplied to the anode 12 side and air (oxygen: oxidant) supplied to the cathode 13 side. At the same time, the electric power is supplied to the load. Incidentally, if it is a vehicle, the load is a traveling motor, a power storage device (for example, a capacitor or a battery), an auxiliary machine such as an air compressor 31, and the like.

  The anode system 20 is a system that supplies hydrogen to the anode 12 of the fuel cell stack 10 and discharges hydrogen from the anode 12, and includes a hydrogen tank 21, a hydrogen cutoff valve 22, a regulator 23, an ejector 24, and a purge valve 27, In addition, a gas-liquid separator A described later is provided.

  The hydrogen shut-off valve 22 is, for example, an electromagnetically operated type, and is provided at the outlet of the hydrogen tank 21. The hydrogen shut-off valve 22 is connected to the hydrogen tank 21 through a predetermined pipe. The hydrogen shut-off valve 22 may be an in-tank type configured integrally with the hydrogen tank 21.

  The regulator 23 is provided on the downstream side of the hydrogen shut-off valve 22 and has a function of reducing the pressure of the high-pressure hydrogen gas supplied from the hydrogen tank 21 to a pressure suitable for supplying the fuel cell stack 10. The regulator 23 is connected to the hydrogen cutoff valve 22 by a predetermined pipe.

  The ejector 24 is a kind of vacuum pump for recirculating unreacted hydrogen discharged from the anode 12 side to the anode 12 of the fuel cell stack 10. In addition, the ejector 24 is connected to the regulator 23 through a predetermined pipe and is connected to the inlet on the anode 12 side of the fuel cell stack 10.

  The purge valve 27 is provided in the middle of the pipe P4 branched from the pipe P3 that forms the hydrogen circulation path C, and has a function of opening the valve as appropriate to discharge impurities accumulated in the anode system 20. Incidentally, the hydrogen circulation path C includes a pipe P1 connecting the ejector 24 and the inlet of the fuel cell stack 10 on the anode 12 side, an outlet of the fuel cell stack 10 on the anode 12 side, and a tank 25 of the gas-liquid separator A described later. And a pipe P3 connecting the tank 25 and the ejector 24 to each other.

  The cathode system 30 is a system that supplies air (oxygen) to the cathode 13 of the fuel cell stack 10 and exhausts air and the like from the cathode 13, and includes an air compressor 31 and a humidifier 32.

  The air compressor 31 is composed of a supercharger or the like driven by a motor, and has a function of taking air outside the vehicle (outside air), compressing it, and supplying it to the cathode 13.

  The humidifier 32 includes, for example, a hollow fiber membrane module in which a plurality of water permeable membranes are bundled and accommodated in a case, and air from the air compressor 31 is circulated on one side of the inside and outside of the hollow fiber membrane, The other side has a function of humidifying the air from the air compressor 31 by circulating the exhaust off-gas (wet air, generated water) discharged from the cathode 13 of the fuel cell stack 10.

  The dilution system 40 has a function of diluting hydrogen discharged from the fuel cell stack 10 and includes a dilution device 41. The dilution device 41 is connected to the humidifier 32 by a pipe P5 and has a retention chamber (not shown) that retains the air discharged from the cathode 13 of the fuel cell stack 10. The dilution device 41 is connected to a drain valve 26 of a gas-liquid separation device A, which will be described later, by a pipe P6, and is connected to the purge valve 27 by a pipe P4. As a result, the hydrogen discharged from the purge valve 27 is diluted to the specified hydrogen concentration by the air staying in the dilution device 41 and then discharged outside the system (outside the vehicle).

  The control system 50 includes an ECU 51 (Electronic Control Unit). The ECU 51 is configured to collectively control the fuel cell system 1, and in particular, based on a detection signal from a water detection sensor 29 of the gas-liquid separator A described below, the gas-liquid separator The drain valve 26 of A is configured to be controlled according to the procedure described later. The ECU 51 corresponds to “control means” in the claims, and includes a CPU (Central Processing Unit), a memory, a program, and the like. Further, as will be described later, the ECU 51 counts a predetermined time for determining the presence / absence of water based on a detection signal from the water detection sensor 29 (hereinafter, also simply referred to as “determination time”). A timer is provided. Incidentally, when the detection signal for detecting the presence of water is input until the determination time has elapsed, the ECU 51 determines that water is present, and inputs the detection signal for not detecting the presence of water until the determination time has elapsed. Confirm that there is no water. The “detection signal that does not detect the presence of water” here includes a case where a detection signal that detects the presence of water is not input (no signal). Such a fixed time is set to about 500 milliseconds in the present embodiment.

Next, the gas-liquid separation device A of the present embodiment will be described.
As shown in FIG. 1, the gas-liquid separator A separates water (product water) by-produced when the fuel cell stack 10 generates an electromotive force as described above. This water corresponds to the “liquid” in the claims. Incidentally, this water is by-produced on the cathode 13 side, and is mainly discharged from the fuel cell stack 10 together with the cathode offgas (air) via the pipe P5 connected to the cathode 13 side. Then, the cathode off-gas containing water is discharged out of the system (outside the vehicle) through the diluting device 41.

On the other hand, the water that has permeated the electrolyte membrane 11 from the cathode 13 side and moved (leaked) to the anode 12 side together with the anode offgas (hydrogen) through the pipe P2 connected to the outlet on the anode 12 side is the fuel cell stack. 10 is discharged.
In the present embodiment, a gas-liquid separator A for separating water mixed in the anode off gas from the anode off gas will be described. The anode off gas corresponds to “gas” in the claims.

  The gas-liquid separator A includes a tank 25, a drain valve 26, a pipe P7 connecting the tank 25 and the drain valve 26, a water detection sensor 29 provided in the pipe P7 on the upstream side of the drain valve 26, The ECU 51 is mainly configured. The drain valve 26 corresponds to a “drain mechanism” in the claims, the pipe P7 corresponds to a “discharge pipe part”, and the water detection sensor 29 corresponds to a “liquid detection unit”.

As shown in FIG. 2, the tank 25 separates water from the anode off-gas (hydrogen) introduced from the anode 12 side of the fuel cell stack 10 via the pipe P2. And this tank 25 returns the anode off gas after separating water to the anode 12 via the piping P3 and the piping P1. 2, illustration of the ejector 24 (refer FIG. 1) arrange | positioned between the piping P3 and the piping P1 is abbreviate | omitted.
The tank 25 discharges water separated from the anode off gas to the diluting device 41 through the pipe P7, the drain valve 26, and the pipe P6.

  The drain valve 26 is disposed between the pipe P7 and the pipe P6, and is configured by an open command signal output from the ECU 51 and an open / close valve such as an electromagnetic valve that opens and closes in response to the close command signal, as will be described later. Has been.

  The water detection sensor 29 detects the presence or absence of water (produced water) in the pipe P7 and outputs a detection signal to the ECU 51 (see FIG. 1). The water detection sensor 29 is not particularly limited as long as it detects water, and examples thereof include a capacitance sensor and an ultrasonic sensor. The sensitivity of the water detection sensor 29 is adjusted so as to detect water flowing so as to fill the inside of the pipe P7 without detecting water droplets or a water film adhering to the inner wall surface of the pipe P7.

  In the pipe P7 in the present embodiment, the capacity V1 from the water detection sensor 29 to the drain valve 26 and the capacity V2 from the connecting portion between the tank 25 and the pipe P7 to the drain valve 26 are set as follows.

  The capacity V1 is a response time from when the water detection sensor 29 detects that no water is present in the pipe P7 until the drain valve 26 operates, in other words, until the drain valve 26 is closed. The volume is set such that the anode off gas in the pipe P7 does not reach the drain valve 26. That is, the capacity V1 is set to a capacity at which the anode off gas is not discharged more reliably from the drain valve 26.

The capacity V1 is a state in which the flow rate of the anode off gas flowing into the tank 25 (see FIG. 2) from the anode 12 (see FIG. 2) side of the fuel cell stack 10 is maximized, in other words, the tank 25 (see FIG. 2). When the amount of water separated in (1) becomes the maximum, the anode off-gas is not discharged from the drain valve 26, and the capacity is set such that water can be efficiently discharged.
Although the details will be described later, the capacity V1, as shown in FIG. 3 (c), when it is not water W is present in the pipe P7 continues until after the settling time t ₁ described above is detected the anode off-gas G in the pipe P7 is set to a volume that does not reach the drain valve 26 at its settling time t _1.

The capacity V2 is a state in which the flow rate of the anode off gas flowing from the anode 12 (see FIG. 2) side of the fuel cell stack 10 into the tank 25 (see FIG. 2) is maximized, in other words, in the tank 25 (see FIG. 2). When the amount of water to be separated becomes the maximum, the capacity is set such that the water does not overflow from the pipe P7 to the tank 25 side.
The details will be described later, but as shown in FIG. 3 (f), the volume V2, while the drain valve 26 is closed, the water W in the piping P7 continues until after the settling time t ₁ described above is when it is present is detected, the water in the settling time t ₁ flows from the tank 25 side to the pipe P7 is set to a volume that does not reach the junction between the tank 25 and the pipe P7.

  Next, the operation of the gas-liquid separator A will be described. FIGS. 3A to 3F referred to here are schematic diagrams showing the behavior of water and anode off-gas flowing through the pipe P7 (discharge pipe portion) in relation to the operation of the drain valve 26 (drain mechanism). Yes, FIG. 3 (g) shows the opening / closing timing of the drain valve 26 (the timing of the operation of the drain mechanism) in correspondence with the behavior of water and anode off-gas shown in FIGS. 3 (a) to 3 (f). It is a time chart. FIG. 4 is a flowchart showing an operation procedure of the ECU 51 (control means).

  First, when the fuel cell system 1 (see FIG. 1) is activated to start power generation, as described above, the anode off gas containing water is sent into the tank 25 through the pipe P2 shown in FIG. The tank 25 shown in FIG. 2 separates water from the anode off gas, and then returns the anode off gas to the anode 12 side through the pipe P3 and feeds water into the pipe P7.

In this gas-liquid separator A, for example, as shown in FIG. 3A, it is assumed that the water W and the anode off gas G are fed into the pipe P7. More specifically, in the state shown in FIG. 3A (hereinafter referred to as “(a) state”), the water W fed into the pipe P <b> 7 is discharged from the drain valve 26. In other words, the water detection sensor 29 outputs a detection signal for detecting the presence of the water W to the ECU 51 (see FIG. 1), and the ECU 51 continues to input the detection signal even after the fixed time t ₁ has passed. It is in a state where its existence is confirmed. Therefore, in this (a) state, as shown in FIG. 3 (g), the drain valve 26 is open. The anode off gas G sent to the pipe P <b> 7 following this water W is located on the upstream side of the water detection sensor 29, and its presence is not detected by the water detection sensor 29.

Next, as shown in FIG. 3 (b), when the water W is discharged from the drain valve 26 and the anode off gas G reaches the position of the water detection sensor 29, the water detection sensor 29 detects the presence of water. A detection signal that is not detected is output to the ECU 51 (see FIG. 1). By the way, ECU51 is, until the settling time _{t 1} has elapsed, not to confirm its existence. That is, the ECU 51 in the state shown in FIG. 3B (hereinafter referred to as “(b) state”) is in a state in which the drain valve 26 is opened as shown in FIG.

Then, as shown in FIG. 3C, the anode off gas G flows into the downstream side of the water detection sensor 29 after the fixed time t ₁ has elapsed. And, ECU51 is, to confirm that the settling time _{t 1} is water W does not exist by that elapses. That is, as shown in FIG. 3G, the drain valve 26 is closed in the state shown in FIG. 3C (hereinafter referred to as “(c) state”).
At this time, as described above, the capacity V1 of the pipe P7 is set so that the anode off-gas G does not reach the drain valve 26, so that the anode off-gas G is prevented from being discharged from the drain valve 26. . Incidentally, the water W flows into the pipe P7 from the tank 25 side following the anode off gas G.

  Next, as shown in FIG. 3D, the drain valve 26 is closed, so that the water W that has entered the pipe P <b> 7 following the anode off gas G flows toward the drain valve 26. In the state shown in FIG. 3D (hereinafter referred to as “(d) state”), the closed state continues as shown in FIG. Incidentally, the water W flows into the pipe P7 from the tank 25 side in a state where the drain valve 26 is closed.

Then, as shown in FIG. 3 (e), when the water W that has flowed into the pipe P <b> 7 is filled on the drain valve 26 side and the water W reaches the position of the water detection sensor 29, the water detection sensor 29. Outputs a detection signal for detecting the presence of water to the ECU 51 (see FIG. 1). By the way, ECU51 is, until the settling time _{t 1} has elapsed, not to confirm its existence. That is, the ECU 51 in the state shown in FIG. 3E (hereinafter referred to as “(e) state”) is in a state of closing the drain valve 26 as shown in FIG.

Next, as shown in FIG. 3 (f), in a state in which drain valve 26 is closed, at the time it reaches the settling time t _1, still, ECU 51 does not determine the presence of water. That is, as shown in FIG. 3G, the drain valve 26 is closed in the state shown in FIG. 3F (hereinafter referred to as “(f) state”).
At this time, as described above, the capacity V2 of the pipe P7 is set to a volume at which the water W does not reach the joint between the tank 25 and the pipe P7. Therefore, even if the amount of the water W separated in this state increases rapidly, the water W is prevented from overflowing into the tank 25.

Then, when the determination time t ₁ has elapsed from the state (f) described above, the ECU 51 determines the presence of the water W. As a result, as shown in FIG. 3G, the ECU 51 returns to the state (a) described above, opens the drain valve 26, and discharges the water W from the pipe P7.

Next, the operation procedure of the ECU 51 will be described mainly with reference to FIG.
As shown in FIG. 4, the ECU 51 (see FIG. 1) inputs a detection signal for detecting the presence or absence of water in the pipe P7 (see FIG. 1) from the water detection sensor 29 (see FIG. 1) (step S1). . Then, the ECU 51 determines whether this detection signal is the detection of the presence of water or the detection of the absence of water, in other words, whether the detection signal is a signal for detecting the presence of water ( Step S2).

  Next, when the detection signal is a signal for detecting the presence of water (Yes in step S2), the ECU 51 counts the input time of the detection signal with the timer, so that the input time is determined as described above. It is determined whether or not it has elapsed (step S3). At this time, if the fixed time has not elapsed (No in step S3), the process returns to step S1. That is, the opening of the drain valve 26 at this time is prohibited. And when fixed time has passed (Yes of Step S3), it is determined that water exists in the piping P7, and an open command is output to the drain valve 26 (Step S4). The subroutine ends. As a result, as described above, the drain valve 26 is opened, and water is discharged from the pipe P7 toward the diluting device 41.

  On the other hand, in step S2, the ECU 51 counts the input time of the detection signal by the timer when the detection signal is a signal that does not detect the presence of water (No in step S2). It is determined whether or not the determined time has elapsed (step S5). At this time, if the fixed time has not elapsed (No in step S5), the process returns to step S1. That is, the opening of the drain valve 26 at this time is prohibited.

  When the determined time has elapsed (Yes in step S5), the ECU 51 determines that water does not exist in the pipe P7, and outputs a close command to the drain valve 26 (step S6). ), This subroutine ends. As a result, the drain valve 26 is closed and the anode off gas is prevented from being discharged from the pipe P7.

The gas-liquid separator A as described above can achieve the following operational effects.
Unlike the conventional gas-liquid separator (see, for example, Patent Document 1), this gas-liquid separator A is configured to detect water based not on the water level in the tank 25 but on whether or not water is present in the pipe P7. And the timing of the end of the drainage are determined, and the following effects are produced.
In the gas-liquid separator A, unlike the conventional gas-liquid separator (see, for example, Patent Document 1), the accurate determination of the timing described above is hindered by the fluctuation of the water level due to the inclination of the gas-liquid separator A or the like. Therefore, the gas-liquid separator A can improve the reliability.

  Further, in this gas-liquid separator A, unlike the conventional gas-liquid separator (see, for example, Patent Document 1), water can be guided only into the pipe P7 and the tank 25 can be emptied. Even if the amount of generated water increases rapidly, the overflow of water from the tank 25 is prevented. As a result, this gas-liquid separator is prevented from overflowing water and can improve the water replenishment capability.

  Moreover, in this gas-liquid separator A, since the above-mentioned timing is determined depending on whether water is present in the pipe P7, this gas-liquid separator A is a conventional gas-liquid separator (for example, patent document). 1), the anode off-gas can be prevented from being discharged out of the fuel system regardless of the presence or absence of water in the tank 25. As a result, this gas-liquid separator A can reduce the loss of unreacted hydrogen in the anode off-gas, so that the fuel gas utilization efficiency can be improved.

  Moreover, in this gas-liquid separator A, unlike conventional gas-liquid separators (see, for example, Patent Document 1), in order to prevent overflow of water and loss of unreacted hydrogen in the anode off-gas. Since the enlargement of the tank 25 is avoided, the gas-liquid separator A can be reduced in size and weight.

  Further, in this gas-liquid separator A, the timing can be controlled by one water detection sensor 29 provided in the pipe P7. Therefore, this gas-liquid separator A is a conventional gas-liquid separator that requires two sensors. Unlike the separation device (for example, see Patent Document 1), the control of the water detection sensor 29 can be simplified, and the manufacturing cost of the gas-liquid separation device A itself can be reduced.

  Further, in this gas-liquid separator A, the drain valve 26 operates after the capacity V1 of the pipe P7 from the water detection sensor 29 to the drain valve 26 is detected by the water detection sensor 29 that no water is present. The response time until the anode off-gas of the pipe P7 is set to a volume that does not reach the drain valve 26. As a result, the gas-liquid separator A can more reliably prevent the anode off gas from being discharged from the drain valve 26.

  Further, in this gas-liquid separator A, the capacity V1 of the pipe P7 from the water detection sensor 29 to the drain valve 26 is such that the state in which the flow rate of the anode off-gas from the fuel cell stack 10 is maximized has elapsed. When it is determined that water is not continuously present, the volume is set such that the anode off-gas in the pipe P7 does not reach the drain valve 26 in this determined time. As a result, the gas-liquid separator A can more reliably prevent the anode off gas from being discharged from the drain valve 26.

  Further, in this gas-liquid separator A, the capacity V2 of the pipe P7 from the connection portion between the tank 25 and the pipe P7 to the water detection sensor 29 is such that the flow rate of the anode off gas from the fuel cell stack 10 is maximized. When it is determined that water is continuously present until the fixed time elapses, the volume is set such that the water flowing into the pipe P7 from the tank 25 side at the fixed time does not reach the connecting portion. As a result, this gas-liquid separator A is prevented from overflowing water from the pipe P7 side to the tank 25 side.

  Further, in this gas-liquid separator A, the ECU 51 prohibits the opening of the drain valve 26 until the fixed time elapses, so that the gas-liquid separator A discharges the anode off-gas from the drain valve 26. Can be prevented more reliably.

  As described above, according to this gas-liquid separation device A, water can be drained accurately without detecting the water level in the tank 25, and water can be discharged by only one water detection sensor 29.

As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment.
In the above embodiment, the gas-liquid separator A that separates the anode offgas and water has been described. However, the present invention may be a gas-liquid separator that separates the cathode offgas and water. This gas-liquid separator can be provided in the pipe P5 (see FIG. 1).

  In the above embodiment, only the tank 25 for separating the anode off gas and water is provided, but a tank for storing water may be provided separately in the pipe P7 between the tank 25 and the water detection sensor 29.

  In the above embodiment, the drain valve 26 is constituted by an on-off valve, but the present invention may use a flow rate adjusting valve.

  In the said embodiment, although the piping P7 is formed with the straight pipe | tube, unless this invention inhibits achievement of the subject, the piping P7 may be formed with the curved pipe.

  The gas-liquid separator A as described above can be applied to the fuel cell system 1 mounted on a movable body such as a vehicle, a ship, or an aircraft.

1 is an overall configuration diagram of a fuel cell system using a gas-liquid separator according to an embodiment. It is a schematic diagram for demonstrating the structure of the gas-liquid separation apparatus of this embodiment. (A) to (f) is a schematic diagram showing the behavior of water flowing through the discharge pipe and the anode off-gas in relation to the operation of the drain mechanism, and (g) is the water shown in (a) to (f). 6 is a time chart showing the timing of the operation of the drain mechanism in correspondence with the behavior of the anode off gas. It is a flowchart which shows the operation | movement procedure of a control means.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel cell system 10 Fuel cell stack 25 Tank 29 Water detection sensor (liquid detection means)
51 ECU (control means)
P7 Piping (discharge pipe part)
t1 Determination time A Gas-liquid separator W Water (liquid)
G Anode off gas (gas)

Claims (7)

A gas-liquid separation device for separating a liquid mixed in a gas from a fuel cell from the gas,
A tank for separating the liquid from the gas;
A drain mechanism for discharging the liquid from the tank;
A discharge pipe portion connecting the tank and the drain mechanism;
A liquid detection means provided on the discharge pipe portion upstream of the drain mechanism to detect the presence or absence of the liquid;
Control means for controlling a discharge amount of the liquid in the drain mechanism based on a detection signal from the liquid detection means;
A gas-liquid separation device comprising:   The drain mechanism is a drain valve, and the control means controls to open the drain valve when it is determined by the detection signal that the liquid is present. The gas-liquid separation device according to 1.   The drain mechanism is a drain valve, and when the control means determines that the liquid is not present based on the detection signal, the drain mechanism controls the drain valve to be closed. The gas-liquid separation device according to 1.   The capacity of the discharge pipe section from the liquid detection means to the drain mechanism is a response time from the detection of the absence of the liquid by the liquid detection means to the operation of the drain mechanism. The gas-liquid separation device according to any one of claims 1 to 3, wherein the gas in the pipe section is set to a volume that does not reach the drain mechanism.   The capacity of the discharge pipe section from the liquid detection means to the drain mechanism is the time when the presence of the liquid is determined by the liquid detection means when the flow rate of the gas from the fuel cell is maximized. The volume is set so that the gas in the discharge pipe portion does not reach the drain mechanism at the time when it is detected that the liquid does not exist continuously until the time elapses. The gas-liquid separator according to any one of claims 1 to 3.   The capacity of the discharge pipe section from the connection between the tank and the discharge pipe section to the liquid detection means is such that the liquid flow rate of the gas from the fuel cell is maximized by the liquid detection means. When it is detected that the liquid is continuously present until a time until the presence / absence of the liquid is determined, the liquid flowing into the discharge pipe portion from the tank side at the time is detected as the connection. The gas-liquid separator according to any one of claims 1 to 5, wherein the volume is set so as not to reach the portion.   The drain mechanism is a drain valve, and the control unit prohibits the opening of the drain valve until a time until the presence or absence of the liquid is determined by the liquid detection unit elapses. The gas-liquid separator according to claim 1.

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