JP5494535B2 - Water storage tank - Google Patents

Description

  The present invention relates to a water storage tank. Specifically, the present invention relates to a water storage tank that can suppress breakage due to volume expansion accompanying freezing of contents during cold weather.

  There are many devices including a container such as a water storage tank for storing water or a liquid mainly composed of water. In these devices, there is a concern that the water storage tank may be damaged due to volume expansion accompanying freezing of the liquid during cold weather such as when used outdoors. Specific examples of such devices include vehicles, water heaters, fuel cells, and the like.

  As countermeasures against freezing of the liquid stored in the water tank as described above, for example, the liquid is discharged from the water tank when the apparatus is stopped (for example, see Patent Document 1 or 2), or the water tank Heating the liquid stored in the interior of the container (for example, see Patent Document 3) has been proposed.

  However, in order to heat the liquid stored in the water storage tank as described above, means for heating the liquid (for example, a heating medium, a heating medium flow passage, a heating medium circulation pump, a heating medium heating means, etc.) This is not always desirable from the viewpoint of reducing the weight of the apparatus and reducing the manufacturing cost.

  Furthermore, depending on the type and use of the apparatus provided with the water storage tank, the liquid stored in the water storage tank may not be completely discharged. For example, in an argon circulation type hydrogen engine, water as a combustion product of hydrogen as a fuel is contained in argon as a working gas, and there is a risk of causing problems such as a reduction in the specific heat ratio of the working gas. Therefore, in such an engine, a condenser is provided in the flow path of burned gas discharged from the combustion chamber to condense moisture (water vapor) in argon, and the condensed water is separated and stored in a water storage tank.

  Even in the above-described configuration, there is a possibility that the condensed water stored inside the water storage tank freezes when it is cold, causing problems such as damage to the storage tank. However, in this case, the water storage tank communicates with a condenser provided in the flow path of burned gas. Therefore, as a countermeasure against freezing of condensed water, if condensed water stored inside the storage tank is completely discharged, argon to be recirculated as a working gas to the combustion chamber passes through the discharge path of the storage tank. Leak to the outside. That is, in order to maintain the sealing of argon as a working gas, the condensed water stored inside the water storage tank is not completely discharged, and a predetermined amount of condensed water is always left inside the water storage tank. It is known to be.

  As described above, in this technical field, effective measures to eliminate inconvenience such as breakage of the water storage tank due to volume expansion accompanying freezing of water stored in the water storage tank or a liquid mainly composed of water. There is an ongoing demand for.

JP 2006-112763 A JP 2009-99355 A JP 2005-1000075 A

  As described above, in this technical field, effective measures to eliminate inconvenience such as breakage of the water storage tank due to volume expansion caused by freezing of water stored in the water storage tank or a liquid mainly composed of water. There is an ongoing demand for.

  The present invention has been made to meet the above demands. More specifically, the present invention eliminates inconvenience such as breakage of a water storage tank due to volume expansion accompanying freezing of water stored in the water storage tank or a liquid containing water as a main component. The purpose is to provide effective measures.

The above object of the present invention is to
A water storage tank for storing water or a liquid mainly composed of water inside,
A water level detecting means for detecting a height of a liquid level of the liquid stored in the water storage tank;
Drainage means for discharging the liquid from the water storage tank; and water level adjustment means for controlling the drainage means to adjust the level of the liquid level detected by the water level detection means;
And in the mechanism having a component serving as a heat source for heating the water tank and the liquid, the water tank is used.
When the component serving as the heat source stops generating heat, the water level adjusting means adjusts the height of the liquid level so that it enters a predetermined first water level range; and the first water level In the portion corresponding to the range, the inner wall surface of the water storage tank has a shape in which the angle at which the wall surface in contact with the liquid and the liquid surface of the liquid intersect is an acute angle,
Characterized by a water tank.

  As described above, according to the present invention, when a heat source (for example, an engine which is a main heat source in a vehicle) having a water storage tank stops generating heat, the level of the liquid stored in the water storage tank is increased. Is adjusted to fall within the first water level range. In a portion corresponding to the first water level range, the angle at which the inner wall surface of the water storage tank in contact with the liquid and the liquid surface of the liquid intersect is an acute angle. Therefore, even if a mechanism (for example, a vehicle) provided with a water storage tank according to the present invention is left outdoors when it is cold, the ambient temperature becomes below the freezing point, and even if the liquid freezes, volume expansion accompanying freezing of the liquid will occur. The resulting stress is relieved and damage to the tank due to volume expansion associated with freezing of the liquid can be prevented.

It is the schematic showing the structure of the system containing the water storage tank which concerns on one embodiment of this invention. It is an enlarged view of the part enclosed with the dashed-dotted line in FIG. It is a flowchart showing the process which performs control which controls the water level of the liquid in a water storage tank performed in the water storage tank which concerns on one embodiment of this invention. It is the schematic showing the structure of the water storage tank which concerns on another embodiment of this invention.

  As described above, the present invention is effective in resolving inconveniences such as breakage of a water storage tank caused by volume expansion accompanying freezing of water stored in the water storage tank or a liquid containing water as a main component. The purpose is to provide appropriate measures.

  As a result of intensive studies to achieve the above object, the present inventor has determined that the inner wall surface of the water storage tank has an acute angle so that the angle between the inner wall surface of the water storage tank in contact with the liquid and the liquid surface of the liquid is an acute angle. It was conceived that the shape caused by the liquid and the height of the liquid surface of the liquid was adjusted to relieve the stress caused by volume expansion associated with the freezing of the liquid and prevent the water tank from being damaged. It is.

That is, the first aspect of the present invention is:
A water storage tank for storing water or a liquid mainly composed of water inside,
A water level detecting means for detecting a height of a liquid level of the liquid stored in the water storage tank;
Drainage means for discharging the liquid from the water storage tank; and water level adjustment means for controlling the drainage means to adjust the level of the liquid level detected by the water level detection means;
And in the mechanism having a component serving as a heat source for heating the water tank and the liquid, the water tank is used.
When the component serving as the heat source stops generating heat, the water level adjusting means adjusts the height of the liquid level so that it enters a predetermined first water level range; and the first water level In the portion corresponding to the range, the inner wall surface of the water storage tank has a shape in which the angle at which the wall surface in contact with the liquid and the liquid surface of the liquid intersect is an acute angle,
This is a water storage tank.

  The material and configuration of the water storage tank are not particularly limited as long as they are inert to the liquid to be stored and have properties such as mechanical strength and heat resistance that can withstand the intended use. Those made from various materials generally known in the art can be used.

  As the water level detection means, various water level sensors generally known in the art can be used according to the application as long as the level of the liquid level stored in the water storage tank can be detected. You can choose the right one. As such a water level sensor, for example, a type that detects the water level by contact with a liquid, such as a float switch or a capacitance sensor, or an ultrasonic sensor, etc., that detects the distance from the liquid level without contact with the liquid. And the like. The water level detection means is configured to detect the height (water level) of the liquid stored in the water storage tank and generate a measurement signal (detection signal) indicating the detected water level.

  Therefore, for example, the water level detection means is connected to an electronic control device, and the electronic control device performs adjustment of the height (water level) of the liquid stored in the water storage tank by the water level adjustment means. It can be used for various controls. Incidentally, the electronic control device refers to an electronic device mainly composed of a known microcomputer including a storage device such as a CPU, a ROM, a RAM, and a nonvolatile memory, and an interface. However, the above description regarding the water level detection means and the electronic control device is merely an example, and the configurations of the water level detection means and the electronic control device are not limited to the above description.

  Next, the drainage means may have any configuration as long as the liquid stored in the water storage tank can be discharged from the water storage tank. For example, the drainage means may include an opening provided at the bottom of the water storage tank and a valve body that opens and closes the opening to start or stop the discharge of liquid. it can. Alternatively, the drainage means includes, for example, an end disposed near the bottom of the water storage tank, a conduit connected to the outside of the water storage tank, and a pump connected to the conduit. You can also The pump is not limited to a specific configuration, and various types of pumps generally used as a liquid pump can be used.

  Whatever configuration the drain means takes, the liquid stored in the water storage tank is controlled by the water level adjusting means based on the liquid level (water level) detected by the water level detecting means. It is configured to start and stop the discharge of water. Such control can be performed by, for example, an instruction signal (control signal) sent from the electronic control device described above. In this case, the water level adjustment means receives a measurement signal (detection signal) sent from the water level detection means and indicating the height (water level) of the liquid stored in the water storage tank. Instructions for determining whether to start or stop discharging the liquid stored in the water storage tank based on the derived water level, and for instructing the drainage means to start or stop discharging the liquid based on the determination It is configured to send a signal (control signal) to the drainage means, and can be implemented as a program stored in a storage device included in the electronic control device. However, the above description regarding the water level adjusting means and the electronic control device is merely an example, and the configurations of the water level adjusting means and the electronic control device are not limited to the above description.

  As described above, in the water storage tank according to the first aspect of the present invention, when the heat source in the mechanism including the water storage tank (for example, the engine that is the main heat source in the vehicle) stops generating heat, the water level adjusting means The height of the liquid level stored in the tank is adjusted to fall within a predetermined first water level range. Specifically, as described above, for example, as described above, the water level adjustment means sends out a measurement signal (detection signal) that indicates the height (water level) of the liquid stored in the water storage tank that is sent from the water level detection means. ). And a water level adjustment means judges whether discharge of the liquid stored in the inside of a water storage tank should be started or stopped based on a water level derived from the measurement signal (detection signal). Further, the water level adjusting means sends an instruction signal (control signal) for causing the drainage means to start or stop the discharge of the liquid based on the determination to the drainage means. The drainage means that has received the instruction signal (control signal) starts or stops discharging the liquid in accordance with the instruction signal (control signal). As a result of such a series of processes, the height (water level) of the liquid stored in the water storage tank is adjusted to fall within a predetermined first water level range.

  On the other hand, as described above, the inner wall surface of the water storage tank is an angle at which the wall surface in contact with the liquid stored in the water storage tank and the liquid surface of the liquid intersect at the portion corresponding to the first water level range. Has a shape with an acute angle. The shape of the inner wall surface of the water storage tank at the portion corresponding to the first water level range is, for example, such that the area of the liquid level of the liquid stored in the water storage tank increases as it goes upward in the vertical direction. Refers to a simple shape. More specifically, the shape of the inner wall surface of the water storage tank refers to, for example, a tapered shape that spreads upward in the vertical direction at a portion corresponding to the first water level range.

  Therefore, in other words, the first water level range is set corresponding to the length in the vertical direction of the portion where the inner wall surface of the water storage tank has the above-described shape (for example, a tapered shape). The level (water level) of the liquid stored in the water storage tank. By setting the first water level range in this way, when the liquid level (water level) of the liquid stored inside the water storage tank falls within the first water level range, the liquid stored inside the water storage tank The wall surface of the water storage tank that is in contact with the liquid surface of the liquid stored in the water storage tank intersects at an acute angle.

  Accordingly, the upper limit of the first water level range is the upper limit position in the vertical direction of the portion where the inner wall surface of the water storage tank has the shape as described above (for example, a tapered shape), that is, the portion and the vertical direction of the portion. Is set in correspondence with the boundary with the portion adjacent to the upper side and not having the shape as described above. In consideration of the above-mentioned mechanism (for example, vehicle) inclination, the inclination of the liquid level with respect to the tank, the position where the water level detection means is disposed, etc., which may occur in a situation where the liquid stored in the water storage tank is assumed to be frozen. Then, the upper limit of the first water level range may be set to a position lower (lower in the vertical direction) than the boundary.

  On the other hand, the lower limit of the first water level range is desirably set as low as possible in the vertical direction in order to reduce the expansion of the volume accompanying freezing of the liquid stored in the water storage tank. However, the lower limit of the first water level range may be limited depending on the use of the water tank, the structure of the water tank (for example, a vehicle), and the like. For example, when the water storage tank according to the present invention is used for storing condensed water condensed / separated from the working gas in the working gas circulation engine, as described above, it passes through the discharge path of the water storage tank. The amount of condensed water necessary to prevent the working gas from leaking to the outside needs to be left in the water storage tank.

  As described above, in the water storage tank according to the first aspect of the present invention, when the component serving as the heat source stops generating heat, the water level adjusting means has a high level of the liquid stored in the water storage tank. The height is adjusted so as to fall within a predetermined first water level range. On the other hand, as described above, the inner wall surface of the water storage tank is an angle at which the wall surface in contact with the liquid stored in the water storage tank and the liquid surface of the liquid intersect at the portion corresponding to the first water level range. Has a shape with an acute angle. As a result, in the water storage tank according to the first aspect of the present invention, when the component serving as the heat source stops generating heat, the wall surface in contact with the liquid stored in the water storage tank and the liquid level of the same liquid The angle at which and intersects is an acute angle.

  As described above, in the water storage tank according to the first aspect of the present invention, when the component serving as the heat source stops generating heat, the liquid stored in the water storage tank is widely downward in the vertical direction. Will have a narrow, generally inverted cone shape. When the liquid freezes, the volume expands with a change from the liquid phase to the solid phase, and stress is applied to the wall surface of the water storage tank as the volume expands. However, as described above, in the water storage tank according to the first aspect of the present invention, the liquid remaining in the water storage tank when the component serving as the heat source stops generating heat has a substantially inverted conical shape. Therefore, when the volume expands due to freezing, slip occurs between the wall surface of the water storage tank and the volume expansion can escape upward in the vertical direction. The stress exerted on the wall surface is relaxed.

  As described above, according to the present invention, when the component serving as the heat source stops generating heat, the liquid level of the liquid stored in the water storage tank is adjusted to fall within the first water level range. The In a portion corresponding to the first water level range, the angle at which the inner wall surface of the water storage tank in contact with the liquid and the liquid surface of the liquid intersect is an acute angle. Therefore, even if the mechanism (for example, a vehicle) provided with the water storage tank according to the first aspect of the present invention is left outdoors when it is cold, the ambient temperature becomes below the freezing point and the liquid freezes. The stress caused by the accompanying volume expansion is relieved, and damage to the tank caused by the volume expansion accompanying freezing of the liquid can be prevented.

  In addition, in the site | part corresponding to a 1st water level range, the shape where the angle which the wall surface in contact with the liquid stored in the inside of a water storage tank and the liquid level of the liquid cross | intersect is an acute angle in the wall surface inside a water storage tank When the volume does not have, when the volume expands due to freezing, slippage hardly occurs between the wall surface of the water storage tank and the volume expansion cannot escape. As a result, the stress exerted on the wall surface of the water storage tank as the volume expands is not relieved, and inconveniences such as damage to the tank cannot be avoided.

  By the way, in a water storage tank, if the mechanism including the water storage tank is shaken or vibrated for some reason (for example, in the case of a water storage tank provided in a vehicle, the vibration or vibration associated with the running of the vehicle, engine operation) The liquid stored in the tank wraps around the inner wall of the tank or the liquid level is disturbed and splashes due to these vibrations and vibrations. There is a risk that the liquid may fly and enter into an unexpected passage or the like. Therefore, in order to avoid such a situation, a wave-dissipating means including a wave-dissipating plate or the like may be provided inside the water storage tank. The wave-dissipating means is, for example, disposed at a position where the wave of the liquid is touched by floating on the liquid surface of the liquid, and causing the liquid wave to interfere with the wave-dissipating plate or allowing the liquid to pass through the wave-dissipating plate. At this time, the kinetic energy accompanying the wave of the liquid is attenuated, and the increase in the amplitude and speed of the wave is suppressed. Therefore, the wave-absorbing means generally has a complicated shape such as having a plurality of fins. The material constituting the wave-dissipating means can be appropriately selected from various materials known in the technical field, and is inactive with respect to the liquid stored in the water storage tank. It is not particularly limited as long as it has the mechanical strength necessary to exhibit the wave action and the heat resistance that can withstand the use environment.

  However, as described above, the wave-dissipating means touches the wave of the liquid by floating the wave-dissipating means on the liquid surface (for example, a part of the wave-dissipating means sinks in the liquid and the other part is liquid If the liquid freezes in the state of being disposed at a position (exposed on the surface), the stress caused by the expansion of the volume accompanying the freezing of the liquid acts on the wave-absorbing means, and the wave-dissipating means is damaged or deformed. There is a risk of causing problems.

  Therefore, in a water storage tank having the above-described wave-dissipating means, in order to avoid problems such as breakage and deformation of the wave-dissipating means due to expansion of the volume due to freezing of the liquid, when the liquid freezes It is desirable to prevent the wave-dissipating means from touching the liquid.

That is, the second aspect of the present invention is
The water storage tank according to the first aspect of the present invention,
Further comprising a wave-dissipating means for attenuating kinetic energy associated with the wave of the liquid, and the wave-dissipating means being disposed at a position higher than the upper limit of the first water level range;
This is a water storage tank.

  As described above, in the water storage tank according to the present invention, the water level adjusting means enters the predetermined first water level range when the component serving as the heat source in the mechanism including the water storage tank stops generating heat. And adjusting the height of the liquid surface. In addition, in the water storage tank according to the second aspect of the present invention, as described above, the wave-dissipating means is disposed at a position higher (upper in the vertical direction) than the upper limit of the first water level range. As a result, in the water storage tank according to the second aspect of the present invention, in a situation where the liquid stored in the water storage tank is assumed to be frozen, it is higher than the liquid level of the liquid (upper in the vertical direction). The wave-dissipating means is disposed at the position. Therefore, when the liquid freezes, the wave-dissipating means is not in contact with the wave-dissipating means, and therefore the wave-dissipating means is damaged or deformed due to the stress caused by the volume expansion accompanying the freezing of the liquid. The problem is reduced. In addition, the inclination of the mechanism (for example, vehicle) including the water storage tank, the inclination of the liquid surface with respect to the tank, the shape and structure of the wave-dissipating means, which may occur in a situation where the liquid stored in the water storage tank is assumed to be frozen. For example, an appropriate margin may be provided between the upper limit of the first water level range and the position where the wave-dissipating means is disposed.

  By the way, as a mechanism having a component that serves as a heat source for heating the water storage tank and its contents in which the water storage tank according to the present invention is used, for example, a vehicle such as a vehicle equipped with an internal combustion engine (engine), power generation, etc. Machine. For example, assuming that the mechanism is a vehicle, when the vehicle is in operation (in this case, even if the vehicle is not running, it is assumed that the vehicle is in operation if the drive source is operating). Generally, the vehicle is warmed up by the heat generated by the operation of the engine, motor, dynamo, etc., and the liquid in the water storage tank is also maintained at a temperature higher than the freezing point. On the other hand, when these components serving as heat sources stop operating, heat generation also stops, and the temperature of the vehicle and the water storage tank eventually becomes equal to the ambient temperature. Therefore, if the vehicle is left outside when the vehicle is cold or the ambient temperature falls below the freezing point, the liquid in the water storage tank may freeze. As described above, the heat source that has a great influence on whether or not the water stored in the water storage tank or the liquid containing water as a main component is frozen includes an engine, a motor, a dynamo, and the like. However, the engine is the biggest heat source.

Therefore, the third aspect of the present invention is
The water storage tank according to any one of the first aspect and the second aspect of the present invention, wherein the component serving as the heat source is an engine. The engine is not limited to a specific type, and the fuel and its combustion mode are not particularly limited (more details will be described later).

  By the way, there are various types of engines in the technical field, and an engine called a working gas circulation engine is also known among them. This working gas circulation type engine supplies fuel, oxygen, and working gas to the combustion chamber to burn the fuel, and circulates the burned gas discharged from the combustion chamber through the circulation path (circulation passage) to the combustion chamber. It is an engine to be resupplied (re-supplied). In the engine, moisture contained in burned gas (circulation gas) flowing into the condensing means interposed in the circulation passage is separated as condensed water by the condensing means, stored in a water storage tank, and discharged out of the system. The The burned gas from which moisture has been removed is discharged from the outlet of the condensing means to the circulation passage and is resupplied (circulated) to the combustion chamber.

  Naturally, even in a water storage tank that stores condensed water that is condensed and separated from burned gas in the working gas circulation engine, there is a concern that the condensed water may freeze during cold weather. Therefore, the working gas circulation type engine is intended to reduce the damage of the water storage tank due to the stress caused by the expansion of the volume due to the freezing of the water stored in the water storage tank or the liquid mainly composed of water. It is clear that it is desirable as a target to apply.

That is, the third aspect of the present invention is
A water storage tank according to the third aspect of the present invention,
The engine is a working gas circulation engine having a condensing means for condensing moisture contained in the working gas discharged from the engine as condensed water and separating it from the working gas, and the liquid is the condensed water about,
This is a water storage tank.

  As described above, the working gas circulation engine supplies fuel, oxygen, and working gas to the combustion chamber to burn the fuel, and burns the exhausted gas discharged from the combustion chamber to the combustion chamber (circulation). The engine is circulated (re-supplied) through the passage portion. In the engine, moisture contained in burned gas (circulation gas) flowing into the condensing means interposed in the circulation passage is separated as condensed water by the condensing means, stored in a water storage tank, and discharged out of the system. The The burned gas from which moisture has been removed is discharged from the outlet of the condensing means to the circulation passage and is resupplied (circulated) to the combustion chamber.

  The condensing means may have any configuration as long as it can separate and remove moisture contained in the burned gas. For example, the condensing means condenses the moisture contained in the burned gas by exchanging heat with the atmosphere of the burned gas (circulated gas) flowing from the circulation passage section to form the condensed water. The condenser which isolate | separates the water | moisture content which became condensed water by heat exchange may be sufficient. This condenser may be a water-cooled condenser using cooling water as a refrigerant or an air-cooled condenser.

In addition, as the fuel used in the engine, various fuels such as gasoline, light oil, natural gas, propane, and hydrogen can be used. However, as described above, in the present embodiment, as described above, the present invention is applied to a water storage tank that stores condensed water that is condensed and separated from burned gas in a working gas circulation engine. It is intended to reduce the damage of the water storage tank due to the stress caused by the expansion of the volume accompanying the freezing of the condensed water. Accordingly, the fuel is assumed to produce water (H ₂ O) as a combustion product.

  The fuel can be stored in a fuel storage unit (for example, a tank, a cylinder, etc.) having a configuration corresponding to the phase of the fuel (for example, liquid phase, gas phase, etc.) in the operating state of the engine. In addition, the fuel is injected into the working gas from the fuel storage unit, for example, by direct injection into the combustion chamber of the engine (so-called “in-cylinder injection”) or by injection into the intake port of the engine. You may mix beforehand.

  The injection means for performing such fuel injection is, for example, opening and closing the injection port by a valve body in response to the instruction signal from the electronic control device described above, and when the injection port is opened by the valve body, It may be an injection valve that injects fuel by the pressure of the supplied fuel. Furthermore, the pressure used for fuel injection may be based on, for example, the pressure of the fuel gas in the fuel tank as the fuel storage when the fuel is in the gas phase, for example, increasing the pressure of the fuel May be based on the fuel pressure raised by the compressor (eg, compressor, pump, etc.). Furthermore, the pressure used for fuel injection is regulated so as not to exceed a predetermined set pressure by a fuel injection pressure adjusting means (for example, a pressure regulator) interposed between the fuel storage section and the injection means. It may be.

  Moreover, as an oxidizing agent used for burning the fuel, for example, oxygen can be used. Oxygen can be stored, for example, in an oxygen storage section such as a cylinder, for example, directly injected into the combustion chamber of the engine or before being supplied into the combustion chamber of the engine. It may be premixed with the working gas.

  Furthermore, the fuel combustion mode can be appropriately selected according to the properties of the fuel used, engine specifications, and the like. More specifically, for example, fuel is directly injected into the combustion chamber (so-called “high pressure injection”) at a predetermined time within a high compression state in which a gas containing at least oxygen and working gas is compressed in the combustion chamber. ") And the fuel may be subjected to diffusion combustion. Further, as described above, the fuel previously mixed with the working gas may be ignited by the spark generated from the ignition means provided in the combustion chamber, and the spark ignition combustion may be performed.

  For example, various gases such as air and nitrogen can be used as the working gas. From the viewpoint of increasing the thermal efficiency of the engine, for example, an inert gas having a large specific heat ratio such as argon, neon, and helium is used. It is desirable to use it. When a gas having such a large specific heat ratio is used as the working gas, the engine can be operated with higher thermal efficiency than when a gas having a relatively small specific heat ratio (for example, air, nitrogen, etc.) is used as the working gas. it can.

  In the working gas circulation engine, as described above, the water storage tank for storing the condensed water communicates with the condenser provided in the flow path of the burned gas. Therefore, if the condensed water stored inside the water storage tank is completely discharged as a countermeasure against freezing of the condensed water, the working gas to be recirculated to the combustion chamber is discharged to the outside via the discharge path of the water storage tank. Leaks. That is, in order to keep the working gas sealed, the condensate stored in the water storage tank should not be completely discharged, and a predetermined amount of condensate should always be left in the water storage tank. Therefore, in this embodiment, it is necessary to set the lower limit of the first water level range with this point in mind.

  By the way, as described above, various gases such as air and nitrogen can be used as the working gas. For example, the thermal efficiency of the engine can be increased and, for example, nitrogen oxide (NOx) can be used. In order to reduce pollutants that are required to suppress emissions from the viewpoint of environmental protection, it is desirable to use, for example, a monoatomic inert gas. Examples of the monoatomic inert gas include helium, neon, and argon, which belong to rare gases. Among them, argon is widely used as the working gas for internal combustion engines.

Moreover, as above-mentioned fuel, various fuels, such as gasoline, light oil, natural gas, propane, hydrogen, can be used as mentioned above. However, when petroleum fuel such as gasoline is used, carbon dioxide (CO ₂ ) is also generated as a combustion product, so that it is necessary to separate and remove carbon dioxide from the circulating gas. Also, carbon dioxide emission is not desirable from the viewpoint of global warming, which has been regarded as a problem recently. Furthermore, these petroleum fuels may generate harmful substances such as sulfur oxides (SOx) as combustion products. As an environmentally friendly fuel without such concerns, it is particularly desirable to use hydrogen that produces only water (H ₂ O) as a combustion product.

Accordingly, the fifth aspect of the present invention provides
A water storage tank according to the fourth aspect of the present invention,
The working gas is argon, and the fuel in the engine is hydrogen,
This is a water storage tank.

As described above, in the fifth aspect of the present invention, hydrogen having a high specific heat ratio and using inert argon as a working gas and producing only water (H ₂ O) as a combustion product is used as a fuel. In the working gas circulation engine to be used, the water storage tank according to the present invention is used. As a result, in this embodiment, a mechanism (equipped with a working gas circulation engine that can suppress the discharge of environmental pollutants such as carbon dioxide, nitrogen oxides, sulfur oxides, etc. while operating with high thermal efficiency ( For example, in a vehicle), even if the condensed water in the water storage tank freezes, the stress caused by the volume expansion accompanying the freezing of the condensed water is relieved, and the water tank is damaged due to the volume expansion accompanying the freezing of the condensed water. Can be prevented.

  As described above, according to the present invention, even when a mechanism (for example, a vehicle) provided with a water storage tank is left outdoors during cold weather, the ambient temperature becomes below the freezing point and the liquid in the water storage tank is frozen. Since the angle between the inner wall surface of the water storage tank in contact with the liquid and the liquid surface of the liquid is an acute angle, the stress caused by volume expansion associated with the freezing of the liquid is relieved, and the freezing of the liquid Damage to the tank due to volume expansion can be prevented.

  Hereinafter, water storage tanks according to some embodiments of the present invention will be described with reference to the accompanying drawings. However, the following description is for illustrative purposes only, and the scope of the present invention should not be construed as being limited to the following description.

1) Configuration of a system including a water storage tank As described above, FIG. 1 is a schematic diagram showing a configuration of a system including a water storage tank according to one embodiment of the present invention. The system includes a main body portion 110 of a working gas circulation engine, a fuel supply portion 130, an oxygen supply portion 140, a circulation passage portion (working gas circulation passage portion) 150, and a condensing means 160. This engine supplies oxygen and working gas (for example, argon gas) to the combustion chamber, and compresses the gas to inject fuel (for example, hydrogen gas) into the gas that has become high temperature and pressure. It is a type of engine that performs diffusion combustion. 1 shows only a cross section of a specific cylinder of the engine main body 110, but in the case of an engine including a plurality of cylinders, the other cylinders have the same configuration.

  The engine main body 110 is not limited to a specific configuration, but in this embodiment, the cylinder head 111, the cylinder 112 formed by the cylinder block, the piston 113 reciprocating in the cylinder, and the crankshaft 114, a piston reciprocating motion comprising a connecting rod 115 for connecting the piston 113 and the crankshaft 114 to convert the reciprocating motion of the piston 113 into a rotational motion of the crankshaft 114, and an oil pan 116 connected to the cylinder block. Type engine.

  In this case, a piston ring is disposed on the side surface of the piston 113 (not shown), and a space formed by the cylinder head 111, the cylinder 112, and the oil pan 116 is formed by the piston 113 into a combustion chamber on the top surface side of the piston. 117 and a crankcase 118 for accommodating the crankshaft.

  The cylinder head 111 is formed with an intake port communicating with the combustion chamber 117 and an exhaust port communicating with the combustion chamber 117 (none is shown). An intake valve 121 that opens and closes the intake port is disposed in the intake port, and an exhaust valve 122 that opens and closes the exhaust port is disposed in the exhaust port (both not shown). Further, the cylinder head is provided with a fuel injection valve 123 that directly injects fuel (for example, hydrogen gas) into the combustion chamber 117.

  The fuel supply unit 130 includes a fuel tank 131 (for example, a hydrogen gas tank), a fuel gas passage 132, a fuel gas pressure regulator (not shown), a fuel gas flow meter (not shown), a surge tank (not shown), and the like. Can be provided. The oxygen supply unit 140 includes an oxygen tank 141 (oxygen gas tank), an oxygen gas passage 142, an oxygen gas pressure regulator (not shown), an oxygen gas flow meter (not shown), and an oxygen gas mixer (not shown). Can be provided.

  Note that the specific configurations and operations of the engine main body 110, the fuel supply unit 130, and the oxygen supply unit 140 are well known in the art with respect to, for example, a working gas circulation hydrogen engine. Detailed explanation is omitted.

  The circulation passage portion 150 includes first and second passage portions (first and second flow path forming pipes) 151 and 152, and an inlet portion and an outlet portion are provided between the first passage portion 151 and the second passage portion 152. The condensing means 160 which has a part is interposed. The circulation passage 150 constitutes a “circulation path of burned gas (circulation gas)” that connects the exhaust port and the intake port outside the combustion chamber 117.

  The first passage portion 151 connects the exhaust port and the inlet portion of the condensing means 160. The second passage portion 152 connects the outlet portion of the condensing means 160 and the intake port, and the oxygen supply portion 140 joins in the middle through an oxygen gas mixer or the like (not shown).

  As described above, the condensing unit 160 includes an inlet portion and an outlet portion of burned gas (circulated gas). Further, the condensing means 160 includes a cooling water inlet 161, a cooling water outlet 162, and a condensed water outlet 163, and a cooling water circulation section connecting the cooling water inlet and the cooling water outlet is provided with a cooling water. A heat radiator (radiator) 164 used for cooling is interposed.

  The condensing means 160 introduces moisture (water vapor) contained in burned gas (circulated gas) introduced from the inlet and discharged from the outlet from the cooling water inlet 161 and passes through the inside of the condenser 160. After that, it is cooled by the cooling water discharged from the cooling water discharge port 162 and condensed. The condensed water once accumulates at the bottom of the condensing means 160 and is discharged out of the system through the condensed water discharge port 163 when a valve body (not shown) for opening and closing the condensed water discharge port 163 is opened. That is, in this embodiment, the bottom part of the condensing means 160 (the part surrounded by the one-dot chain line in FIG. 1) functions as a water storage tank according to the present invention, and the condensed water discharge port 163 and the above valve The body constitutes the drainage means. In addition, a water level sensor that constitutes a water level detecting means is disposed at the bottom of the condensing means 160 as a water storage tank according to the present invention (not shown). On the other hand, the gas from which moisture has been removed (separated) is discharged from the outlet of the condensing means 160 to the circulation passage 150 (second passage 152).

  As described above, in the present embodiment, the bottom of the condensing unit 160 functions as a water storage tank according to the present invention, but is connected to the bottom of the condensing unit 160 via a conduit or the like, for example. A separate water storage tank may be provided. In this embodiment, the condensing unit 160 uses a water-cooled condenser that uses cooling water as a refrigerant. However, the condensing unit 160 may use a refrigerant other than water, and air ( An air-cooled condensing unit that condenses the moisture of the gas passing through the inside by air blowing) may be provided.

  As described above, various gases such as air and nitrogen can be used as the working gas. For example, it is desirable to use an inert gas having a large specific heat ratio such as argon, neon, or helium. . When a gas having such a large specific heat ratio is used as the working gas, the engine can be operated with higher thermal efficiency than when a gas having a relatively small specific heat ratio (for example, air, nitrogen, etc.) is used as the working gas. it can. In addition to the above, it is desirable to use an inert gas from the viewpoint of contributing to environmental protection by reducing discharge of pollutants such as nitrogen oxides. Among these inert gases, argon is widely used as a working gas for internal combustion engines.

Further, as described above, various fuels such as gasoline, light oil, natural gas, propane, and hydrogen can be used as the fuel. However, the present embodiment is a water storage tank that stores condensed water produced as a combustion product of fuel of a working gas circulation engine and obtained by condensing and separating moisture (water vapor) contained in burned gas by the condensing means 160. However, it is intended to reduce the damage of the water storage tank caused by the expansion of the volume accompanying the freezing of the condensed water during cold weather. Therefore, the fuel is assumed to produce water (H ₂ O) as a combustion product, and in particular, from the viewpoint of contributing to prevention of global warming without discharging carbon dioxide (CO ₂ ). It is desirable to use hydrogen as a fuel.

2) Configuration of water storage tank As described above, in the present embodiment, the bottom of the condensing means 160 functions as a water storage tank according to the present invention. Therefore, the bottom of the condensing means 160 corresponding to the water storage tank according to the present invention will now be described with reference to FIG. Note that FIG. 2 is an enlarged view of a portion surrounded by a one-dot chain line in FIG. 1 as described above.

As shown in FIG. 2, the bottom of the condensing unit 160 corresponding to the water storage tank according to the present invention has a side surface 201 of the condensing unit 160 having a substantially cylindrical shape (for example, a substantially cylindrical shape) and a substantially inverted conical shape ( For example, the bottom surface 202 of the condensing means 160 having a substantially inverted conical shape is a horizontal cross section at the boundary surface having the same cross section (in FIG. 2, the upper limit 221 (= the upper limit water level H _U ) of the first water level range 220). In combination). In FIG. 2, the level of the condensed water stored at the bottom of the condensing means 160 corresponding to the water storage tank according to the present invention is at the height of the water surface 211 indicated by a broken line, and this water level is indicated by a first dashed line. It is located between the upper limit 221 (= upper limit water level H _U ) of the water level range 220 and the lower limit 222 (= lower limit water level H _L ) of the first water level range 220 (that is, it is in the first water level range 220). As a result, the angle (θ) 212 formed by the water surface 211 of the condensed water and the bottom surface 202 of the condensing means 160 having a tapered shape spreading upward in the vertical direction becomes an acute angle.

  As described above, in the situation shown in FIG. 2, the water level of the condensed water stored in the bottom (water storage tank) of the condensing means 160 is in the first water level range 220. Therefore, when the condensed water freezes while keeping the water level as it is, slipping easily occurs between the bottom surface 202 of the water storage tank when the volume expands as the condensed water freezes. As a result, the volume expansion due to the condensation water freezing can escape upward in the vertical direction, and the stress on the inner wall surface (bottom surface 202 of the condensing means 160) of the water storage tank is relieved with the volume expansion. Inconvenience such as breakage of the water storage tank can be avoided.

In this embodiment, the upper limit 221 (= the upper limit water level H _U ) of the first water level range 220 is set to the side surface 201 of the condensing unit 160 having a substantially cylindrical shape and the condensing unit having a substantially inverted conical shape. The height of the boundary surface with the bottom surface 202 of 160 was set. However, the upper limit 221 (= the upper limit water level H _U ) of the first water level range 220 is the same as that of the water storage tank that may occur in a situation where the liquid stored in the water storage tank is assumed to be frozen as described above. In consideration of the inclination of the mechanism (for example, the vehicle), the inclination of the liquid level with respect to the tank, the position where the water level detecting means is disposed, etc., the position may be set lower than the boundary surface.

On the other hand, regarding the lower limit 222 (= the upper limit water level H _L ) of the first water level range 220, in this embodiment, it is assumed that the water storage tank according to the present invention is applied to a working gas circulation engine. Thus, it is necessary to set so that the amount of condensed water required for maintaining the hermetic sealing of the working gas remains in the water storage tank.

  On the other hand, in a situation where the water level of the condensed water stored in the bottom (water storage tank) of the condensing means 160 exceeds the upper limit 221 of the first water level range 220, the water surface 211 intersects the side surface 201 of the condensing means 160. Sliding between the condensing means 160 and the inner wall surface is unlikely to occur, and the volume expansion due to freezing of the condensed water cannot escape. As a result, as the volume expands, the stress on the inner wall surface of the water storage tank (the side surface 201 and the bottom surface 202 of the condensing means 160 is not relieved, and there remains a high possibility of causing inconveniences such as breakage of the water storage tank.

3) Control of the water level in the water storage tank As described above, in the water storage tank according to the present invention (in this embodiment, the bottom of the condensing means 160), the water storage tank and its contents are contained in a mechanism including the water storage tank. When the component that is a heat source for heating a certain liquid (the working gas circulation engine 110 in this embodiment) stops generating heat, the liquid level adjusting means enters the predetermined first water level range 220 so as to enter the liquid level. The height of the liquid surface (the water surface 211 of condensed water in this embodiment) is adjusted. Such a series of processes will now be described with reference to FIG. FIG. 3 is a flowchart showing the process for controlling the water level of the liquid in the water tank, which is executed in the water tank according to one embodiment of the present invention as described above. The series of processes shown in the flowchart can be repeatedly executed at a sufficiently fast cycle, for example, using a clock built in an electronic control device (not shown).

As shown in FIG. 3, in this embodiment, first, in step S301, the water level (H _W ) of the condensed water in the water storage tank is acquired by a water level detection means (not shown). Next, in step S302, it is determined whether or not the heat source (engine in this embodiment) of the mechanism (vehicle in this embodiment) including the water storage tank is stopped. The details of this determination are well known to those skilled in the art, and a description thereof will be omitted.

When it is determined that the heat source is stopped (step S302: Yes), the condensate water level (H _W ) acquired in step S301 is the upper limit 221 (= the upper limit water level H _U ) of the first water level range 220. It is determined whether or not (step S303). When it is determined that the acquired water level H _W exceeds the upper limit water level H _U (that is, H _W > H _U ) (step S303: Yes), the condensed water discharge port 163 is opened to start draining the condensed water. (Step S305). On the other hand, when it is determined in step S303 that the water level H _W of the condensed water does not exceed the upper limit water level H _U (that is, H _W ≦ H _U ) (step S303: No), the condensed water discharge port 163 is opened. Close and stop drainage of condensed water (step S306). In order to avoid the above process from being repeatedly executed indefinitely when the engine that is the heat source is stopped, for example, the execution of the above process is stopped based on the elapsed time since the engine stopped. You may comprise.

  Incidentally, in the present embodiment, the amount of condensed water in the water storage tank gradually increases as long as the engine is operated. Therefore, if the condensed water is left to accumulate in the water storage tank, the inside of the condensing means 160 will eventually be filled with the condensed water, and it will not be possible to remove moisture from the burned gas. Condensed water may be mixed in and cause serious damage to the engine. Therefore, the water level of the condensed water in the water storage tank during engine operation is managed not for the purpose of avoiding the inconvenience due to the freezing of the condensed water as in the present invention but for the purpose of eliminating such concerns. This is widely done in working gas circulation engines.

That is, when it is determined in step S302 that the heat source is not stopped (that is, in operation) (step S302: No), the water level (H _W ) of the condensed water obtained in step S301 is the above-described level. In consideration of such a concern, it is determined whether or not a predetermined upper limit water level during operation (H _R ) is exceeded (step S304). Obtained the water level _{H W} exceeds the operation time limit level _{H R (i.e., H} W> H _R) if it is determined (step S304: Yes), the drainage of condensed water by opening the condensed water outlet 163 Start (step S307). On the other hand, in step S304, when the water level _{H W} of the condensed water does not exceed the operating time limit level _{H R} (i.e., _{H W} ≦ _{H R)} is determined (step S304: No), the condensed water discharge port 163 is closed and drainage of the condensed water is stopped (step S308).

As described above, the series of processing represented by the flowchart shown in FIG. 3 is repeatedly executed at a sufficiently fast cycle, for example, using a clock incorporated in an electronic control device (not shown). Therefore, when the engine that is the heat source is stopped, whether or not the water level H _W of the condensed water exceeds the upper limit 221 (= the upper limit water level H _U ) of the first water level range 220 is determined in a predetermined period. The process is repeatedly performed, and based on the determination result, the water level of the condensed water is controlled to fall within the first water level range 220.

  As a result, a state in which the liquid surface (the water surface 211 of the condensed water in the present embodiment) intersects the inner wall surface of the water storage tank (the bottom surface 202 of the condensing means 160 in the present embodiment) at an acute angle is achieved. The Therefore, as described above, even if a mechanism (for example, a vehicle) provided with a water storage tank is left outside in cold weather, the ambient temperature becomes below the freezing point and the condensed water is frozen. The volume expansion due to water freezing can be released upward in the vertical direction. As a result, the stress exerted on the inner wall surface of the water tank (the bottom surface 202 of the condensing means 160) as the volume expands is alleviated, and inconveniences such as breakage of the water tank can be avoided.

1) Configuration of Water Storage Tank Having Wave-Dissipating Means Next, a water storage tank according to another embodiment of the present invention will be described with reference to FIG. As described above, FIG. 4 is a schematic diagram illustrating the configuration of a water storage tank according to another embodiment of the present invention. In the water storage tank shown in FIG. 4, wave-absorbing means for attenuating kinetic energy associated with the wave of the condensate is added to the water storage tank shown in FIG. 2.

That is, in this embodiment, the wave-dissipating means 310 for attenuating the kinetic energy associated with the condensate wave is provided at the bottom of the condensing means 160 as a water storage tank. The wave-dissipating means 310 in the present embodiment is a structure including a plurality of wave-dissipating plates 311, and attenuates kinetic energy associated with the condensate wave caused by vibrations or vibrations received by the water storage tank. This suppresses an increase in the amplitude and speed. As shown in FIG. 4, the wave-absorbing means 310 is disposed at a position higher than the upper limit 221 (= the upper limit water level H _U ) of the first water level range 220.

2) Control of the water level in the water storage tank In the water storage tank according to this embodiment , the water level of the condensed water can be controlled by a series of processes represented by the flowchart shown in FIG. it can. That is, when the heat source (for example, the engine that is the main heat source in the vehicle) in the mechanism including the water storage tank is stopped, the water level is adjusted by the water level adjusting means so that the water level of the condensed water falls within the first water level range 220. .

In the water storage tank according to the present embodiment, as described above, the wave-dissipating means 310 is disposed at a position higher than the upper limit 221 (= upper limit water level H _U ) of the first water level range 220 (upward in the vertical direction). Has been. As a result, in the water storage tank according to the present embodiment, the condensed water in the water storage tank can be assumed to be frozen. The wave-absorbing means 310 is present at the upper position in FIG. Therefore, when the condensed water freezes, since the condensed water is not in contact with the wave-absorbing means 310, the wave-absorbing means 310 is damaged or deformed due to the stress caused by the expansion of the volume accompanying the freezing of the condensed water. Problems are reduced.

As described above, the inclination assumed in the mechanism including the water storage tank, the inclination of the condensed water with respect to the water storage tank (in the present embodiment, the bottom of the condensing means 160), the shape and structure of the wave-absorbing means 310, and the like are taken into consideration. Thus, an appropriate margin may be provided between the upper limit 221 (= the upper limit water level H _U ) of the first water level range 220 and the disposition position of the wave-dissipating means 310.

On the other hand, according to the series of processes represented by the flowchart shown in FIG. 3, when the heat source (for example, the engine that is the main heat source in the vehicle) in the mechanism including the water storage tank is not stopped, the water level of the condensed water is the above-described level. It is adjusted by the water level adjusting means so as not to exceed the operating upper limit water level (H _R ). That is, in the water storage tank according to this embodiment, while the heat source (for example, the engine that is the main heat source in the vehicle) in the mechanism including the water storage tank is operating, the water level of the condensed water is the above-described upper limit water level during operation ( H _R ) in the vicinity (water surface 312 indicated by a two-dot chain line in FIG. 4).

As is clear from FIG. 4, in the situation where the water level of the condensed water is maintained in the vicinity of the operating upper limit water level (H _R ), a part of the wave-absorbing means 310 is more than the water surface 211 of the condensed water. It sinks in the lower water, and the remaining part is exposed above the water surface 211 of the condensed water. That is, when a heat source (for example, an engine that is a main heat source in a vehicle) in a mechanism including a water storage tank is operating, the wave-dissipating means 310 touches the wave of condensed water, and the kinetic energy associated with the wave of condensed water is reduced. The water level of the condensate is maintained at a desired height to attenuate and suppress increases in wave amplitude and velocity.

  As described above, in the water storage tank according to this embodiment including the wave-dissipating unit 310, when the heat source (for example, the engine that is the main heat source in the vehicle) in the mechanism including the water-storage tank is operating, the wave-dissipating unit The water level of the condensed water is maintained at such a height that 310 can exert a wave-dissipating effect. On the other hand, when the engine which is a heat source is stopped, the water level of the condensed water is maintained at a height lower than the wave-absorbing means 310. Therefore, since the wave-absorbing means 310 is not touching the condensed water, the possibility that the wave-absorbing means 310 is damaged or deformed due to the stress caused by the expansion of the condensed water is eliminated even if the condensed water is frozen. In addition, at this water level, the water surface 211 of the condensed water and the bottom surface 202 of the condensing means 160 intersect at an acute angle. Therefore, even if the condensed water is frozen, the volume of the condensed water is reduced. Along with the expansion, the stress on the inner wall surface of the water tank (the bottom surface 202 of the condensing means 160) is relieved, and inconveniences such as breakage of the water tank can be avoided.

  In the foregoing, for the purpose of illustrating the present invention, several embodiments having specific configurations and combinations of execution procedures have been described, but the scope of the present invention is limited to these exemplary embodiments. Instead, modifications can be appropriately made within the scope of the matters described in the claims and the specification.

DESCRIPTION OF SYMBOLS 110 ... Engine main part, 111 ... Cylinder head, 112 ... Cylinder, 113 ... Piston, 114 ... Crankshaft, 115 ... Connecting rod, 116 ... Oil pan, 117 ... Combustion chamber, 118 ... Crankcase, 121 ... Intake valve, 122 DESCRIPTION OF SYMBOLS ... Exhaust valve, 123 ... Fuel injection valve, 130 ... Fuel supply part, 131 ... Fuel tank, 132 ... Fuel gas passage, 140 ... Oxygen supply part, 141 ... Oxygen tank, 142 ... Oxygen gas passage, 150 ... Circulation passage part, 151 ... 1st channel | path part (1st flow path formation pipe), 152 ... 2nd channel | path part (2nd flow path formation pipe), 160 ... Condensing means, 161 ... Cooling water inlet, 162 ... Cooling water discharge port, 163 DESCRIPTION OF SYMBOLS ... Condensate discharge port, 164 ... Radiator, 201 ... Side surface of condensing means, 202 ... Bottom surface of condensing means, 211 ... Water surface of condensed water when stopped, 21 ... bottom 202 and the angle of the water surface 211 and the condensing means of the condensed water (theta), 220 ... first level range, 221 Te n first upper limit of the level range of 220 (= upper limit water level _H U), 222 ... first level Lower limit 222 (= lower limit water level H _L ) of range 220, 310 ... wave-dissipating means, 311 ... wave-dissipating plate, and 312 ... water level of condensed water during operation

Claims (5)

A water storage tank for storing water or a liquid mainly composed of water inside,
A water level detecting means for detecting a height of a liquid level of the liquid stored in the water storage tank;
Drainage means for discharging the liquid from the water storage tank; and water level adjustment means for controlling the drainage means to adjust the level of the liquid level detected by the water level detection means;
And in the mechanism having a component serving as a heat source for heating the water tank and the liquid, the water tank is used.
When the component serving as the heat source stops generating heat, the water level adjusting means adjusts the height of the liquid level so that it enters a predetermined first water level range; and the first water level In the portion corresponding to the range, the inner wall surface of the water storage tank has a shape in which the angle at which the wall surface in contact with the liquid and the liquid surface of the liquid intersect is an acute angle,
Features a water storage tank. The water storage tank according to claim 1,
Further comprising a wave-dissipating means for attenuating kinetic energy associated with the wave of the liquid, and the wave-dissipating means being disposed at a position higher than the upper limit of the first water level range;
Features a water storage tank.   The water storage tank according to claim 1 or 2, wherein the heat source component is an engine. The water storage tank according to claim 3,
The engine is a working gas circulation engine having a condensing means for condensing moisture contained in the working gas discharged from the engine as condensed water and separating it from the working gas, and the liquid is the condensed water about,
Features a water storage tank. The water storage tank according to claim 4,
The working gas is argon, and the fuel in the engine is hydrogen,
Features a water storage tank.

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