JPH04249867A - Housing opening and closing mechanism for liquid fuel cell - Google Patents

Abstract

PURPOSE:To quickly start and stop a fuel cell by stopping air supply concurrently with stopping fuel supply to a cell stack. CONSTITUTION:Fluid pressure is supplied to actuators 9a and 9b for opening and closing a window 10a, taking in air in a fuel cell housing 16, and a window 10b, discharging the air, by branching a part of fuel supplied to a cell stack 4. Adjustment for this purpose is made by the discharge pressure of a flow rate controller 8 and a pump 3.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a housing opening/closing mechanism for starting and stopping a small liquid fuel cell system that can be mounted on an automobile.

0002

BACKGROUND OF THE INVENTION Conventionally, in order to stop a liquid fuel cell, that is, to stop it from an operating state, and to put it into rest, that is, to put it in a non-operating state, it is necessary to cut the air, rather than operating it by cutting the liquid fuel. It has been confirmed that it is easiest to operate and has a better response. As such technology,
There was one described in JP-A-62-10875. The publication states that, in order to prevent the temperature of the electrolyte from rising during the suspension of operation of the fuel cell and to reduce fuel consumption, opening and closing of slits is required to cut off air to the air electrode of the fuel cell. It is shown.

0003

[Problem to be solved by the invention] In the technique of the above publication,
The document discloses manual operation for opening and closing the slit, and suggests that it may be done automatically, but no specific proposal has been made. However, in order to open and close the slit automatically, a power source is required to open and close the slit, but if a power source dedicated to opening and closing is prepared, a space for it will be required.
It is not possible to create an entire fuel cell system that is compact enough to be installed in a car. Furthermore, if electric power generated from a fuel cell is used as the power source, the output of the fuel cell will decrease. Furthermore, in order to open and close automatically, the slit opening and closing mechanism needs to have a simple structure, and it is also necessary to be able to delicately control the opening and closing.

[0004] Therefore, the present invention aims to automatically supply air to the air electrode using a slit in order to avoid excessive temperature rise of the liquid fuel cell and prevent durability deterioration, and to maintain a safe resting state. To provide a housing opening/closing mechanism for a liquid fuel cell that has a simple structure and allows fine control without using a dedicated power source or fuel cell power for opening and closing a slit. moreover,
An object of the present invention is to quickly start and stop a fuel cell by stopping the supply of air to the cell stack at the same time as the supply of fuel.

[0005]

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention provides a fuel circulation circuit having a pump for circulating and supplying liquid fuel to a cell stack and recovering it;
A flow controller provided in the middle of the fuel circulation circuit where liquid fuel goes from the pump to the cell stack, a pressure supply circuit branched from the fuel circulation circuit between the pump and the flow controller, and the pressure supply circuit. The liquid fuel cell housing opening/closing mechanism is comprised of an actuator actuated by pressure-fed liquid fuel and a door that opens and closes according to the stroke of the actuator.

[0006]

[Operation] If there is no large flow resistance in the fuel circulation supply circuit and the discharge pressure of the pump is sufficient, the pressure to the actuator is determined by the flow rate controller in the fuel circulation supply circuit and the discharge flow rate of the pump. That is, when the discharge amount of the pump is small, the throttling effect of the flow controller is not sufficient even if the discharge pressure is kept constant, and the pressure supplied to the actuator is also small. Conversely, when the discharge flow rate of the pump is large and the discharge pressure is kept constant, the throttling effect of the flow rate controller is large and the supply pressure increases as it approaches the discharge pressure. Such a relationship can be easily known in advance. Therefore, in order to control the supply pressure to the actuator to move the piston, it can be controlled by controlling the discharge flow rate of the pump, that is, the pump rotation speed, or by controlling the aperture of the flow controller.

FIG. 3 shows a schematic graph of the relationship between the piston travel of the actuator and the supply pressure of the actuator. The relationship between the actuator supply pressure is plotted on the horizontal axis and the piston travel is plotted on the vertical axis. The solid line part indicates that the piston return spring is a single spring, and the dotted line part indicates that the piston return spring is two springs in the middle of the piston's travel.
The case of a stepped double spring is shown. In the case of a single spring, the rate of increase in piston travel does not change even if the supply pressure to the actuator changes;
In the case of a double spring, due to the second stage spring effect, even if the supply pressure to the actuator increases, the piston travel increases slowly from the middle. Therefore, the door for opening and closing the window for air inflow and outflow, which is opened and closed through the piston, can be gently and finely controlled.

[0008]

Embodiment 1 FIG. 1 is a circuit diagram for explaining a hanging opening/closing mechanism of a liquid fuel cell showing an embodiment of the present invention. The hanging opening/closing mechanism of the liquid fuel cell of the present invention will be explained based on FIG. Reference numeral 1 denotes a fuel circulation circuit for supplying liquid fuel to a cell stack 4 in which a plurality of unit cells of liquid fuel cells are stacked, and for recovering exhaust fuel discharged from the cell stack 4. Liquid fuel is stored in a reservoir 2, and a pump 3 for pumping out the liquid fuel from the reservoir 2 is connected to a suction port of the pump 3 through piping. A discharge port of the pump 3 is connected to a fuel chamber of the cell stack 4 to supply liquid fuel to the cell stack 4. A flow rate controller 8 consisting of an orifice 5 and a flow rate control solenoid 6 for controlling the flow rate of liquid fuel is arranged in the middle of the fuel circulation circuit 1 that connects the pump 3 and the cell stack 4.

On the other hand, the fuel circulation circuit 1 connecting the pump 3 and the flow rate controller is branched in the middle to form a pressure supply circuit 7 for transmitting fluid pressure to two actuators 9a and 9b. Two actuators 9a, 9b
is a piston-cylinder mechanism, and the pistons 15a and 15b of the piston-cylinder mechanism are connected to the cylinder chamber 13 by piston return springs 12a and 12b.
A and 13b are activated to become smaller and smaller.

16 is a housing for a liquid fuel cell;
The cell stack 4 is housed therein. The housing 1
A window 10a for taking in air from the outside and a window 10b for discharging air are opened in two opposing side walls of 6, respectively. The actuators 9a, 9b
Piston rod 1 connected to pistons 15a and 15b of
4a and 14b open the windows 10a and 10b by their reciprocating motion.
Doors 11a and 11b provided at the front door are opened and closed. That is, when the pistons 15a and 15b receive fluid pressure, the door 11a
, 11b open the windows 10a, 10b, and when the fluid pressure decreases, the doors 11a, 11b close the windows 10a, 10b. The actuator 9a is installed at a position to open and close the window 10a for taking in air, and the actuator 9b is installed at a position to open and close the window 10b for discharging air.

Next, the operation of the liquid fuel cell housing opening/closing mechanism of the present invention will be explained. During startup of the liquid fuel cell, the pump 3 sucks regulated fuel from the reservoir 2, discharges it into the fuel circulation circuit 1, and supplies it to the cell stack 4 of the liquid fuel cell. In addition, due to the supply pressure of the pump 3, the partially consumed fuel in the cell stack 4 and undigested fuel are circulated through the fuel circulation circuit 1 to the reservoir 2.

At this time, when the flow rate control solenoid 6 is slightly throttled, pressure is generated in the pressure supply circuit 7, and the pressure is supplied to the two actuators 9a and 9b. Therefore, the pistons 15a and 15b are connected to the piston return spring 1.
2a, 12b to move the piston rods 14a, 14b, opening the window 10a for taking in air and the window 10b for discharging air into the housing 16 of the liquid fuel cell. . Furthermore, at this time, if the circulation flow rate of liquid fuel to the cell stack 4 is decreasing, the power of the pump 3 may be further increased.

When the liquid fuel cell is stopped, the three pumps are stopped, the flow rate controller solenoid is opened, and the liquid fuel flows from the cylinder chambers 13a and 13b of the two actuators 9a and 9b to the piston return spring 1.
It is discharged by activation of 2a and 12b. Therefore, the piston rods 14a, 14b move to close the window 10a for introducing air into the housing 16 of the liquid fuel cell and the window 10b for discharging air.

Furthermore, when adjusting the output of the fuel cell other than when it is stopped, the flow rate controller 8 and/or the discharge pressure of the pump 3 can be adjusted appropriately to control the appropriate amount of fuel and the amount of air to be supplied. Can be done.

[0015]

Embodiment 2 FIG. 2 is a circuit diagram for explaining a hanging opening/closing mechanism for a liquid fuel cell showing another embodiment of the present invention. FIG. 2 is a circuit diagram for explaining the hanging opening/closing mechanism of the liquid fuel cell in FIG.
, 9b, the piston return springs 22a, 2
All other configurations are the same except for 2b. In this embodiment, the piston return spring 22a
, 22b are arranged in two stages in parallel, and the springs act in stages.

When the pistons 15a and 15b move back due to fluid pressure and the first stage spring contracts by about half, the second
The springs in the second stage contact the pistons 15a and 15b and contract. Therefore, when the first stage spring contracts, the piston travel is large relative to the supply pressure of the actuators 9a, 9b, but when the second stage spring works, the piston travel is small relative to the supply pressure of the actuators 9a, 9b. . That is, initially piston rod 1
4a and 14b move back greatly, so the door 11a
, 11b are opened and closed, but the piston rods 14a and 14b move back slowly because the second-stage spring works from the middle, and the doors 11a and 11b are opened and closed slowly. Therefore, the windows 10a, 1 of the housing 16
The opening and closing of the doors 11a and 11b provided at 0b can be smoothly adjusted to half-open.

Here, P is the fluid supply pressure, A is the cylinder area of the actuator, k1 is the spring constant of the first stage spring, k2 is the spring constant of the second stage spring, l1
When is the amount of deflection of the first stage spring and l2 is the amount of deflection of the second stage spring, the following formula holds true. When there are only one stage of piston return springs 22a and 22b, the following equation is obtained.

[0018]

[Math 1]

Piston return springs 22a, 22
When b is two stages, the following equation is obtained.

[0020]

[Math 2]

[0021]

Effects of the Invention The present invention provides a fuel circulation circuit having a pump for circulating, supplying and recovering liquid fuel to a cell stack, and a fuel circulation circuit in which the liquid fuel is directed from the pump to the cell stack. a flow rate controller provided midway; a pressure supply circuit branched from the fuel circulation circuit between the pump and the flow rate controller; an actuator operated by liquid fuel pumped by the pressure supply circuit; and a stroke of the actuator. This is a liquid fuel cell housing opening/closing mechanism consisting of a door that opens and closes with a door, and has the following effects (1) to (4). (1) The power for opening and closing the housing window uses only the circulating supply pressure of fuel, and no external energy is required for opening and closing, so there is little loss of energy. (2) Since the opening and closing of the window door of the housing can be controlled by the discharge flow rate of the pump, the structure of the opening and closing mechanism is simple. (3) By gradually increasing or decreasing the discharge flow rate of the pump, opening and closing are performed gradually, and
It is also possible to fix it in a half-open position. Furthermore, gentle starting and stopping becomes possible. Therefore, to prevent the fuel leaking into the electrolyte while the fuel cell is inactive from rapidly catalytically burning and overheating at the air electrode as soon as the door is opened, the flow rate of the pump is gradually increased and the door is slowly opened. This can be prevented by opening and closing. (4) Air supply can be started and stopped at the same time as fuel supply is started and stopped, and a special sensor for this purpose is not required.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram for explaining a hanging opening/closing mechanism of a liquid fuel cell according to an embodiment of the present invention.

FIG. 2 is a circuit diagram for explaining a hanging opening/closing mechanism of a liquid fuel cell showing another embodiment of the present invention.

FIG. 3 is a diagram schematically illustrating the relationship between the piston travel of the actuator and the supply pressure of the actuator.

[Drawing code]

1 Fuel circulation circuit 2
Reservoir 3 Pump 4 Cell stack 5
Orifice 6
Flow control solenoid 7
Pressure supply circuit 8 Flow rate controllers 9a, 9b Actuators 10a, 10b Windows 11a, 11b Doors 12a, 12b Piston return spring 14a
, 14b piston rod 15a, 15b piston

Claims (1)

[Claims] 1. A fuel cell opening/closing mechanism comprising the following (1) to (5). (1) A fuel circulation circuit having a pump for circulating and supplying liquid fuel to the cell stack and recovering it; (2) A fuel circulation circuit provided in the middle of the fuel circulation circuit where the liquid fuel goes from the pump to the cell stack. (3) a pressure supply circuit branched from the fuel circulation circuit between the pump and the flow controller; (4) an actuator operated by liquid fuel pumped by the pressure supply circuit; 5) A door that opens and closes according to the stroke of the actuator.