Water injection cooling system

Abstract

To provide a water injection cooling system capable of further increasing a temperature of injection water when the injection water adheres to a heat radiation device, to effectively promote heat radiation from the heat radiation device utilizing evaporative latent heat of injection water.SOLUTION: A water injection cooling system 100 comprises: an injection unit 2 that injects injection water onto an outer surface F20 of a fuel cell radiator F2 that radiates heat; and at least one of an injection water heating unit 3 that heats the injection water before it is injected from the injection unit 2, and an ambient temperature increase unit 4 that supplies high-temperature gas having a temperature higher than an ambient temperature of an injection area 40 to the injection area 40 where the injection water is injected by the injection unit 2, thereby increasing the ambient temperature of the injection area 40.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a water injection cooling system. [Background technology]

[0002] 2. Description of the Related Art Conventionally, a water injection cooling system is known that includes an injection unit that injects water into a heat dissipation device that dissipates heat (see, for example, Patent Document 1).

[0003] The above-mentioned Patent Document 1 discloses a fuel cell system equipped with a spray valve that sprays water onto a radiator (heat dissipation device) that dissipates heat. The above-mentioned fuel cell system is configured so that water produced by the fuel cell is deposited on the outer surface of the radiator by the spray valve. The fuel cell system promotes heat dissipation from the radiator by evaporating the water deposited on the outer surface of the radiator. In other words, the fuel cell system promotes heat dissipation from the radiator by utilizing the latent heat of evaporation of the water deposited on the outer surface of the radiator. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 4839514 Summary of the Invention [Problem to be solved by the invention]

[0005] In the fuel cell system of Patent Document 1, water produced in the fuel cell is supplied as is to the spray valve, and the water is sprayed from the spray valve to the radiator, so the temperature of the water is relatively low when it passes through the air and adheres to the radiator. As a result, the water that adheres to the outer surface of the radiator is relatively difficult to evaporate, and it is not possible to effectively promote heat dissipation from the radiator (heat dissipation device) using the latent heat of evaporation of the sprayed water, so improvement is desired.

[0006] The present invention provides a water injection cooling system that can increase the temperature of the injected water when it adheres to a heat dissipation device, thereby effectively promoting heat dissipation from the heat dissipation device by utilizing the latent heat of evaporation of the injected water. [Means for solving the problem]

[0007] As described above, a water injection cooling system according to one aspect of the present invention includes at least one of an injection unit that injects water onto the outer surface of a heat dissipation device that dissipates heat, a water injection heating unit that heats the water before it is injected from the injection unit, and an ambient temperature raising unit that supplies high-temperature gas having a temperature higher than the ambient temperature of the injection area to the injection area into which the water is injected by the injection unit, thereby raising the ambient temperature of the injection area.

[0008] In the water injection cooling system according to the above aspect, as described above, at least one of an injection water heating section that heats the injection water before it is injected from the injection section and an ambient temperature raising section that supplies high-temperature gas having a temperature higher than the ambient temperature of the injection section to the injection section where the injection water is injected by the injection section to raise the ambient temperature of the injection section is provided. In this way, when the injection water heating section is provided, the injection water can be heated in advance by the injection water heating section before it is injected from the injection section. As a result, compared to the conventional case where the generated injection water is injected from the injection section as it is into the heat dissipation device, the temperature of the injection water when it adheres to the heat dissipation device can be made higher, and heat dissipation from the heat dissipation device utilizing the latent heat of evaporation of the injection water can be effectively promoted.

[0009] In addition, when the ambient temperature increasing section is provided, the ambient temperature of the injection area can be increased by the ambient temperature increasing section, so that the temperature drop of the injection water from when the injection water is injected from the injection section until it passes through the air that is the injection area and adheres to the outer surface of the heat dissipation device can be suppressed, and the temperature of the injection water when it adheres to the outer surface of the heat dissipation device can be increased compared to the case where the ambient temperature is not increased. As a result, the temperature of the injection water when it adheres to the heat dissipation device can be increased, and heat dissipation from the heat dissipation device using the latent heat of evaporation of the injection water can be effectively promoted. Furthermore, the ambient temperature of the injection area where the injection water is injected can be increased by the ambient temperature increasing section, so that the relative humidity of the injection area can be reduced. Therefore, the relative humidity of the injection area can be reduced, and the injection area can be provided with a margin for containing more water vapor. This also effectively promotes heat dissipation from the heat dissipation device using the latent heat of evaporation of the injection water.

[0010] In the water injection cooling system according to the above aspect, preferably, the system includes a water injection heating unit and a water injection supply unit that supplies water to the injection unit, the heat dissipation device is configured to allow high-temperature liquid refrigerant to flow through the water injection heating unit, and the water injection heating unit includes a heat exchanger that is provided in the water injection supply unit and heats the water injection water by exchanging heat between the low-temperature water injection water supplied to the injection unit and the high-temperature liquid refrigerant.

[0011] With this configuration, the heat of the high-temperature liquid refrigerant flowing through the heat dissipation device can be effectively utilized by the heat exchanger to heat the injection water before it is sprayed from the spray unit, without using a heater that requires electricity. Also, the liquid refrigerant can be cooled not only in the heat dissipation device but also in the heat exchanger.

[0012] In this case, the heat dissipation device is preferably a fuel cell radiator that cools the liquid refrigerant of the fuel cell stack, and the spray water supply unit is configured to supply water produced in the fuel cell stack to the heat exchanger as spray water.

[0013] With this configuration, the water produced in the fuel cell stack can be effectively used as the water to be sprayed from the spray unit. Also, the heat of the fuel cell stack, which becomes hot due to the generation of electric power, can be effectively used to heat the water produced in the fuel cell stack (the sprayed water) via the liquid refrigerant.

[0014] In the water injection cooling system according to the above aspect, preferably, an ambient temperature increasing unit is provided, and the ambient temperature increasing unit is configured to supply high-temperature gas heated by waste heat discharged from a specified waste heat source to the injection area to increase the ambient temperature in the injection area.

[0015] With this configuration, the ambient temperature increasing section can effectively utilize the waste heat discharged from the predetermined waste heat source to increase the ambient temperature in the injection area.

[0016] The water injection cooling system may be configured as follows.

[0017] (Additional note 1) In the configuration including the above-mentioned jet water supply unit, the jet water supply unit preferably includes a water channel at one end to which the jet unit is connected and through which the jet water flows, a jet water storage unit provided at the other end of the water channel for storing the jet water, and a water pump provided in the water channel for pumping the jet water from the jet water storage unit and supplying it to the jet unit.

[0018] With this configuration, the water can be easily supplied from the water reservoir to the jet section via the water passage by the water pump.

[0019] (Additional note 2) In the configuration in which the above-mentioned spray water heating section includes a heat exchanger, the heat exchanger is preferably provided in a water passage between the spray section and the water pump, and is configured to perform heat exchange between the low-temperature spray water and the high-temperature liquid refrigerant flowing out from the heat dissipation device.

[0020] With this configuration, the low-temperature jet water pumped out from the water pump can be heated immediately before the jet portion by the high-temperature liquid refrigerant flowing out from the heat dissipation device.

[0021] (Additional note 3) In the above-mentioned configuration in which the ambient temperature raising unit supplies high-temperature gas heated by waste heat discharged from a specific waste heat source to the injection area to raise the ambient temperature, preferably, the configuration includes an injection water heating unit and an ambient temperature raising unit, the fuel cell stack is a power source for driving a fuel cell vehicle having an air conditioning condenser, the injection water supply unit is configured to supply water generated in the fuel cell stack which is the power source of the fuel cell vehicle as injection water to the heat exchanger, and the ambient temperature raising unit is configured to supply high-temperature gas heated by waste heat discharged from the air conditioning condenser to the injection area to raise the ambient temperature of the injection area.

[0022] With this configuration, in a fuel cell vehicle, the water produced in the fuel cell stack and the waste heat of the air condenser can be effectively utilized to effectively promote heat dissipation from a heat dissipation device that utilizes the latent heat of evaporation of the injected water.

[0023] (Additional note 4) In the configuration including the above-mentioned injection unit, the injection unit is preferably positioned relative to the heat dissipation device so as to inject water with the direction in which the center line of the injection area of ​​the injected water extends along the outer surface of the heat dissipation device.

[0024] With this configuration, the injection part can be injected along the outer surface of the heat dissipation device, so that the injection part can be spread over a relatively large area of ​​the outer surface of the heat dissipation device and attached relatively thinly. In other words, the injection part can be attached to the outer surface of the heat dissipation device in a thin film that easily evaporates. [Brief description of the drawings]

[0025] [Figure 1]1 is a diagram showing an overall configuration of a water injection cooling system according to a first embodiment, and a fuel cell radiator that is an object to be cooled by the water injection cooling system; [Diagram 2] FIG. 2 is a perspective view showing a state in which water is injected onto a fuel cell radiator from an injection unit (a plurality of nozzles) of the water injection cooling system according to the first embodiment. [Diagram 3] FIG. 11 is a diagram showing an overall configuration of a water injection cooling system according to a second embodiment, and a schematic diagram of an LT radiator of a motor circuit that is an object to be cooled by the water injection cooling system. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] Hereinafter, an embodiment will be described with reference to the drawings.

[0027] [First embodiment] A water injection cooling system 100 according to a first embodiment will be described with reference to Figs.

[0028] (Water Injection Cooling System Configuration) The water injection cooling system 100 shown in Fig. 1 is mounted on a fuel cell vehicle VE having an air condenser A. The water injection cooling system 100 is configured to promote heat dissipation in a fuel cell radiator F2, which is a device that dissipates heat. The fuel cell radiator F2 is an example of a "heat dissipation device" in the claims.

[0029] Specifically, the water injection cooling system 100 is configured to adhere jet water (described later) to the outer surface F20 of the fuel cell radiator F2, evaporate the jet water, and use the latent heat of evaporation (latent heat of vaporization) of the jet water to cool the fuel cell radiator F2. The water injection cooling system 100 is configured to promote the evaporation of the jet water, thereby promoting heat dissipation in the fuel cell radiator F2.

[0030] The fuel cell vehicle VE is equipped with a fuel cell circuit F in which a liquid coolant (antifreeze) circulates. The fuel cell circuit F includes a fuel cell stack F1, a fuel cell radiator F2, a water pump F3, and a circular coolant path F4 through which the liquid coolant flows.

[0031] The above components are connected in series to the coolant passage F4 in the order of the fuel cell stack F1, the fuel cell radiator F2, and the water pump F3. In addition, a water injection heating section 3 (heat exchanger 30) of the water injection cooling system 100, which will be described later, is provided between the fuel cell radiator F2 and the water pump F3.

[0032] The fuel cell stack F1 is a drive source that drives the fuel cell vehicle VE. As an example, the fuel cell stack F1 includes a hydrogen electrode to which hydrogen is supplied, an oxygen electrode to which oxygen is supplied, and a space for storing an electrolyte provided between the hydrogen electrode and the oxygen electrode, and is configured to generate electric power using hydrogen and oxygen. When generating electricity, water (H2O) is produced in the fuel cell stack F1. The water injection cooling system 100 is configured to promote heat dissipation in the fuel cell radiator F2 by using the water produced in the fuel cell stack F1. Details will be described later.

[0033] The fuel cell radiator F2 is configured to cool the liquid coolant in the fuel cell stack F1. As an example, the fuel cell radiator F2 is a so-called fin-and-tube type heat dissipation device. The fuel cell radiator F2 is provided with a fan F21 for blowing air onto the fuel cell radiator F2. The fan F21 is configured to rotate on the rear side of the fuel cell radiator F2 to draw air toward the fuel cell radiator F2.

[0034] The water jet cooling system 100 includes a jet water supply unit 1, a jet unit 2, a jet water heating unit 3, and an ambient temperature increasing unit 4.

[0035] The jet water supply unit 1 is configured to supply jet water to the jet unit 2. The jet unit 2 is configured to jet the jet water to the fuel cell radiator F2 so as to vaporize the jet water on the outer surface F20 of the fuel cell radiator F2. The jet water heating unit 3 is configured to heat the jet water before it is jetted from the jet unit 2. The ambient temperature raising unit 4 is configured to raise the ambient temperature of a jet region 40 into which the jet water is jetted by the jet unit 2.

[0036] (Configuration of the water jet supply unit) The jet water supply unit 1 includes a water passage 10 , a jet water storage unit 11 , and a water pump 12 .

[0037] (Configuration of the "waterway" of the water injection supply section) The water channel 10 has one end connected to the jet unit 2, and is configured so that the jet water flows toward the jet unit 2. That is, the jet unit 2 is disposed at the most downstream position in the flow direction of the jet water flowing through the water channel 10. As an example, the water channel 10 is formed from a pipe made of resin or metal. The water channel may also be formed from a flexible hose or the like.

[0038] (Configuration of the "jet water storage section" of the jet water supply section) The jet water reservoir 11 is provided at the other end of the water passage 10 and is configured to store the jet water. That is, the jet water reservoir 11 is disposed at the most upstream position in the flow direction of the jet water flowing through the water passage 10. As an example, the jet water reservoir 11 is formed of a tank made of resin or metal.

[0039] The jet water storage unit 11 is configured to supply water (H2O) generated in the fuel cell stack F1, which is the power source of the fuel cell vehicle VE, to the heat exchanger 30 (jet water heating unit 3) as jet water. The fuel cell stack F1 is provided with an outlet for the generated water. A water supply flow path F5 that communicates with the outlet of the fuel cell stack F1 is connected to the jet water storage unit 11. Therefore, water is supplied to the jet water storage unit 11 from the fuel cell stack F1 via the supply flow path F5.

[0040] Here, when the amount of power generation (output) per unit time in the fuel cell stack F1 is large, a relatively large amount of water is supplied from the fuel cell stack F1 to the injection water storage section 11 via the water supply passage F5. Therefore, in the water injection cooling system 100, at the same time that water is supplied to the injection water storage section 11, the water supplied mainly from the fuel cell stack F1 is injected from the injection section 2 as injection water.

[0041] On the other hand, when the amount of power generation (output) per unit time in the fuel cell stack F1 is small, the amount of water supplied from the fuel cell stack F1 to the injection water storage section 11 through the water supply passage F5 is relatively small. For this reason, the water injection cooling system 100 injects, from the injection section 2, mainly the water that has been stored in advance in the injection water storage section 11, at the same time that water is supplied to the injection water storage section 11.

[0042] In short, the jet water reservoir 11 functions as a so-called buffer that enables jet water to be injected from the injector 2 even when the amount of water supplied from the fuel cell stack F1 to the jet water reservoir 11 is relatively small.

[0043] (Configuration of the "water pump" of the water injection supply unit) The water pump 12 is provided in the water passage 10 between the injection unit 2 and the injection water storage unit 11, and is configured to pump up the injection water from the injection water storage unit 11 and supply it to the injection unit 2. Thus, the water pump 12 is configured to supply water that is produced in the fuel cell stack F1 and stored in the injection water storage unit 11 to the injection water heating unit 3 (heat exchanger 30) as injection water. As an example, the water pump 12 is an electric pump having a motor and an impeller rotated by the motor.

[0044] (Configuration of the injection part) The injection section 2 includes a plurality of nozzles 20 arranged at predetermined positions relative to the fuel cell stack F1.

[0045] As an example, the number of nozzles 20 is four (see FIG. 2). The fuel cell stack F1 is formed in an elongated shape extending in the left-right direction. The four nozzles 20 are provided, two on each end in the left-right direction, which is the longitudinal direction of the front side of the fuel cell stack F1. Therefore, in the front-rear direction of the fuel cell stack F1, the four nozzles 20 are arranged on the opposite side of the fuel cell stack F1 to the rear side fan F21 described above.

[0046] The nozzle 20 (injection unit 2) is fixed in position relative to the fuel cell radiator F2. The nozzle 20 is disposed relative to the fuel cell radiator F2 so as to inject water with the extension direction of a center line 40a (see FIG. 2) of an injection area 40 of the injection water oriented along the outer surface F20 (front surface) of the fuel cell radiator F2. Specifically, the nozzle 20 is configured to inject water in a direction parallel to the outer surface F20 of the fuel cell radiator F2 and in the longitudinal direction of the fuel cell radiator F2.

[0047] The water injection cooling system 100 is configured such that when water is injected from the nozzle 20 (injection section 2), the water injected from the nozzle 20 is drawn toward the fuel cell radiator F2 by rotating a fan F21 arranged on the rear side of the fuel cell radiator F2.

[0048] Therefore, the water injection cooling system 100 is configured to be able to apply the injected water to a relatively large area of ​​the outer surface F20 extending in the longitudinal direction of the fuel cell radiator F2, and to apply the injected water to the outer surface F20 in a relatively thin state (relatively thin film thickness). As a result, the term "film thickness L [m] of the injected water applied to the outer surface F20" in Equation 1 described later can be reduced, and the evaporation rate V of the injected water applied to the outer surface F20 can be increased.

[0049] (Configuration of the water jet heating section) The jet water heating section 3 is configured to heat the jet water before it is jetted from the jet section 2. The jet water heating section 3 includes a heat exchanger 30. The heat exchanger 30 is provided in the jet water supply section 1.

[0050] Specifically, in the water injection cooling system 100, the heat exchanger 30 is provided in the water passage 10 of the injection water supply unit 1 between the injection unit 2 and the water pump 12 of the injection water supply unit 1. In the fuel cell circuit F, the heat exchanger 30 is provided in the annular coolant passage F4 between the fuel cell radiator F2 and the water pump F3.

[0051] The fuel cell radiator F2 is configured to allow a high-temperature liquid refrigerant to flow therethrough. The heat exchanger 30 is configured to heat the jet water by exchanging heat between the low-temperature jet water supplied to the jet unit 2 and the high-temperature liquid refrigerant. In other words, the heat exchanger 30 is a liquid-liquid heat exchanger. The above-mentioned "high-temperature liquid refrigerant" refers to the high-temperature liquid refrigerant that flows out of the fuel cell radiator F2.

[0052] Specific examples of the temperatures of the liquid refrigerant and the sprayed water before and after heat exchange will be described below. As an example, the temperature of the liquid refrigerant before heat exchange that flows out of the fuel cell radiator F2 and flows into the heat exchanger 30 is about 85°C. The temperature of the sprayed water before heat exchange that flows from the water pump 12 into the heat exchanger 30 is about 25°C. The temperature of the liquid refrigerant after heat exchange that flows out of the heat exchanger 30 is about 80°C. The temperature of the sprayed water after heat exchange that flows out of the heat exchanger 30 is about 60°C. The temperature of the liquid refrigerant that flows out of the fuel cell stack F1 and flows into the fuel cell radiator F2 is about 95°C.

[0053] As an example, the heat exchanger 30 is a heat exchanger having a double-tube structure, but the heat exchanger may be a heat exchanger of other types, such as a so-called shell-and-tube type or a so-called plate type.

[0054] (Configuration of the ambient temperature rising part) The ambient temperature increasing section 4 is configured to supply high-temperature gas heated by waste heat discharged from a predetermined waste heat source A1 to the injection region 40, thereby increasing the ambient temperature of the injection region 40 (the temperature around the fuel cell radiator F2). The predetermined waste heat source A1 is an air condenser A mounted on the fuel cell vehicle VE. The ambient temperature increasing section 4 is configured to supply high-temperature gas heated by waste heat discharged from the air condenser A to the injection region 40, thereby increasing the ambient temperature of the injection region 40. The injection region 40 is at least the region where the fuel cell radiator F2 is disposed, and is also the region on the outer surface F20 side where the injected water adheres to the fuel cell radiator F2.

[0055] The ambient temperature increasing section 4 has a fan F21 that sends high-temperature gas heated by waste heat discharged from the air condenser A to the injection region 40. The ambient temperature increasing section 4 also has a high-temperature gas flow path 41 that flows the high-temperature gas sent to the injection region 40 by the fan F21. The high-temperature gas flow path 41 connects the region where the air condenser A is disposed and the injection region 40.

[0056] As an example, the temperature of the injection area 40 before the ambient temperature increasing section 4 supplies high-temperature gas to the injection area 40 is approximately 40°C, and the temperature of the injection area 40 after the high-temperature gas is supplied is approximately 50°C.

[0057] (Evaporation rate of injected water) The relationship between the water injection cooling system 100 and the evaporation rate V of the injected water will be described. That is, the evaporation rate V of the injected water attached to the outer surface F20 of the fuel cell radiator F2 will be described. Note that "the evaporation rate V of the injected water is high" means that the fuel cell radiator F2 is efficiently cooled by utilizing the latent heat of evaporation of the injected water. In short, the higher the evaporation rate V of the injected water, the higher the cooling efficiency of the fuel cell radiator F2 by the water injection cooling system 100.

[0058] The evaporation rate V of the jet water is calculated based on the following formula 1.

[0059]

number

[0060] The above Sh is the Sherwood number, a dimensionless term. The above D is the water vapor diffusion coefficient, with units of [m 2 / s]. The above C1 is the amount of saturated steam near the injected water attached to the outer surface F20 of the fuel cell radiator F2, and its unit is [kg / m 3 ]. The above C2 is the amount of vapor in the air, and its unit is [kg / m 3 The above L is the film thickness of the sprayed water attached to the outer surface F20, and its unit is [m].

[0061] The water vapor diffusion coefficient D of the above formula 1 is calculated based on the following formula 2.

[0062]

number

[0063] The above t is the temperature of the sprayed water attached to the outer surface F20, and its unit is [℃]. The above po is the standard atmospheric pressure, and its unit is [hpa]. The above p is the atmospheric pressure, and its unit is [hpa].

[0064] The Sherwood number Sh in the above formula 1 is calculated based on the following formula 3.

number

[0065] The above Re is the Reynolds number, a dimensionless term. The above Sc is the Schmidt number, a dimensionless term. The above ρ is the density of air, with units of [kg / m 3 The above u is the wind speed generated by the fan F21, and its unit is [m / s]. The above μ is the viscosity coefficient of air, and its unit is [Pa s].

[0066] Here, from the above formulas 1 and 2, it can be seen that the higher the temperature t of the jet water adhering to the outer surface F20 of the fuel cell radiator F2, the larger the water vapor diffusion coefficient D. Therefore, it can be seen that the higher the temperature t of the jet water adhering to the outer surface F20 of the fuel cell radiator F2, the larger the evaporation speed V of the jet water adhering to the outer surface F20 of the fuel cell radiator F2.

[0067] Therefore, as described above, the water injection cooling system 100 of the first embodiment is configured to increase the temperature t of the injection water attached to the outer surface F20 of the fuel cell radiator F2 by heating the injection water with the injection water heating section 3 (heat exchanger 30) before the injection water is injected from the injection section 2. In other words, the water injection cooling system 100 heats the injection water in the injection water heating section 3 (heat exchanger 30) to create a condition in which the injection water is easily evaporated on the outer surface F20 of the fuel cell radiator F2.

[0068] In the above formula 2, the temperature t of the jet water is set to a power of 1.75. Therefore, it can be seen that the temperature t of the jet water attached to the outer surface F20 of the fuel cell radiator F2 is a term that contributes particularly greatly to increasing the evaporation rate V of the jet water.

[0069] Furthermore, even if the injected water is heated in the injected water heating section 3 (heat exchanger 30) before being injected from the injection section 2, the temperature of the injected water will decrease in the air (injection area 40 where the injected water is injected by the injection section 2) between immediately after being injected from the injection section 2 (nozzle 20) and before it adheres to the outer surface F20 of the fuel cell radiator F2.

[0070] Therefore, as described above, the water injection cooling system 100 of the first embodiment is configured so that the ambient temperature increasing section 4 supplies high-temperature gas having a temperature higher than the ambient temperature of the injection area 40 to the injection area 40 where the injection water is injected from the injection section 2, thereby increasing the ambient temperature of the injection area 40. In other words, the water injection cooling system 100 suppresses a decrease in temperature of the injection water in the air (the injection area 40 where the injection water is injected by the injection section 2), and creates a condition in which the injection water can be easily evaporated on the outer surface F20 of the fuel cell radiator F2.

[0071] In addition, the water injection cooling system 100 of the first embodiment supplies high-temperature gas to the injection area 40 by the ambient temperature increasing unit 4 to increase the ambient temperature of the injection area 40, thereby increasing the amount of saturated steam C1 [kg / m] near the injection water attached to the outer surface F20 of the fuel cell radiator F2 in the above formula 1. 3 As a result, the water injection cooling system 100 reduces the relative humidity in the injection area 40, allowing the injection area 40 (around the fuel cell radiator F2) to accommodate more water vapor. In this way, the water injection cooling system 100 creates conditions that make it easier for the injected water to evaporate on the outer surface F20 of the fuel cell radiator F2.

[0072] (Effects of the first embodiment) In the first embodiment, the following effects can be obtained.

[0073] In the first embodiment, as described above, at least one of the jet water heating section 3 that heats the jet water before it is jetted from the jet section 2 and the ambient temperature raising section 4 that supplies high-temperature gas having a temperature higher than the ambient temperature of the jet area 40 to the jet area 40 into which the jet water is jetted by the jet section 2 to raise the ambient temperature of the jet area 40 is provided. In this way, when the jet water heating section 3 is provided, the jet water can be heated in advance by the jet water heating section 3 before it is jetted from the jet section 2. As a result, compared to the conventional case in which the jet water generated is jetted directly from the jet section to the heat dissipation device, the temperature of the jet water when it adheres to the fuel cell radiator F2 can be made higher, and heat dissipation from the fuel cell radiator F2 utilizing the latent heat of evaporation of the jet water can be effectively promoted.

[0074] In addition, when the ambient temperature raising section 4 is provided, the ambient temperature of the injection area 40 can be raised by the ambient temperature raising section 4, so that the temperature drop of the injection water from when the injection water is injected from the injection section 2 until it passes through the air of the injection area 40 and adheres to the fuel cell radiator F2 can be suppressed, and the temperature of the injection water when it adheres to the outer surface F20 of the fuel cell radiator F2 can be raised compared to the case where the ambient temperature is not raised. As a result, the temperature of the injection water when it adheres to the fuel cell radiator F2 can be made higher, and heat dissipation from the fuel cell radiator F2 using the latent heat of evaporation of the injection water can be effectively promoted. Furthermore, the ambient temperature raising section 4 can raise the ambient temperature of the injection area 40 where the injection water is injected, so that the relative humidity of the injection area 40 can be reduced. Therefore, the relative humidity of the injection area 40 can be reduced, and the injection area 40 can have a margin for containing more water vapor. This also effectively promotes heat dissipation from the fuel cell radiator F2 using the latent heat of evaporation of the injection water.

[0075] Moreover, in the first embodiment, as described above, the fuel cell radiator F2 includes the jet water heating unit 3 and the jet water supply unit 1 that supplies the jet water to the jet unit 2, the fuel cell radiator F2 is configured to flow with a high-temperature liquid refrigerant, and the jet water heating unit 3 includes a heat exchanger 30 that is provided in the jet water supply unit 1 and heats the jet water by exchanging heat between the low-temperature jet water and the high-temperature liquid refrigerant supplied to the jet unit 2. This makes it possible to heat the jet water before it is sprayed from the jet unit 2 by the heat exchanger 30 by effectively utilizing the heat of the high-temperature liquid refrigerant flowing through the fuel cell radiator F2 without using a heater that requires electricity. Also, the liquid refrigerant can be cooled not only by the fuel cell radiator F2 but also by the heat exchanger 30.

[0076] Furthermore, in the first embodiment, as described above, the heat dissipation device is the fuel cell radiator F2 that cools the liquid refrigerant in the fuel cell stack F1, and the injection water supply unit 1 is configured to supply water produced in the fuel cell stack F1 to the heat exchanger 30 as injection water. This allows the water produced in the fuel cell stack F1 to be effectively used as injection water to be injected from the injection unit 2. Also, the heat of the fuel cell stack F1, which becomes hot as a result of generating electric power, can be effectively used to heat the water produced in the fuel cell stack F1 (injection water) via the liquid refrigerant.

[0077] As described above, the first embodiment includes the ambient temperature increasing section 4, which is configured to supply high-temperature gas heated by waste heat discharged from the specified waste heat source A1 to the injection region 40 to increase the ambient temperature of the injection region 40. This allows the ambient temperature increasing section 4 to effectively utilize the waste heat discharged from the specified waste heat source A1 to increase the ambient temperature of the injection region 40.

[0078] Also, in the first embodiment, as described above, the jet water supply unit 1 includes a water passage 10 having one end connected to the jet unit 2 and through which the jet water flows, a jet water storage unit 11 provided at the other end of the water passage 10 for storing the jet water, and a water pump 12 provided in the water passage 10 for pumping up the jet water from the jet water storage unit 11 and supplying it to the jet unit 2. This allows the jet water to be easily supplied from the jet water storage unit 11 to the jet unit 2 via the water passage 10 by the water pump 12.

[0079] In the first embodiment, as described above, the heat exchanger 30 is provided in the water passage 10 between the injection unit 2 and the water pump 12, and is configured to exchange heat between the low-temperature injection water and the high-temperature liquid refrigerant flowing out from the fuel cell radiator F2. This allows the low-temperature injection water delivered from the water pump 12 to be heated before the injection unit 2 by the high-temperature liquid refrigerant flowing out from the fuel cell radiator F2.

[0080] Also, in the first embodiment, as described above, the fuel cell stack F1 is provided with the jet water heating section 3 and the ambient temperature raising section 4, and is a power source for driving the fuel cell vehicle VE having an air condenser A, the jet water supply section 1 is configured to supply water generated in the fuel cell stack F1, which is the power source for the fuel cell vehicle VE, to the heat exchanger 30 as jet water, and the ambient temperature raising section 4 is configured to supply high-temperature gas heated by waste heat discharged from the air condenser A to the jet region 40 to raise the ambient temperature of the jet region 40. In this way, in the fuel cell vehicle VE, the water generated in the fuel cell stack F1 and the waste heat of the air condenser A can be effectively utilized to effectively promote heat dissipation from the fuel cell radiator F2 that utilizes the latent heat of evaporation of the jet water.

[0081] In the first embodiment, as described above, the injection part 2 is disposed relative to the fuel cell radiator F2 so as to inject the water with the center line 40a of the injection area 40 of the injection water extending in a direction along the outer surface F20 of the fuel cell radiator F2. This allows the injection part 2 to inject the water along the outer surface F20 of the fuel cell radiator F2, so that the injection part 2 can be spread over a relatively large range of the outer surface F20 of the fuel cell radiator F2 and adhere relatively thinly. In other words, the injection part 2 can be adhered to the outer surface F20 of the fuel cell radiator F2 in a thin film that easily evaporates.

[0082] [Second embodiment] Next, a water injection cooling system 200 according to a second embodiment will be described with reference to Fig. 3. Unlike the first embodiment in which the water injection cooling system 100 promotes cooling of the fuel cell radiator F2 that dissipates heat, the second embodiment will describe an example in which the water injection cooling system 200 promotes cooling of a LT (Low Temperature) radiator F202 that dissipates heat and is provided in a motor F201a and an inverter F201b. Note that in the figure, the same reference numerals as in the first embodiment are used to denote configurations similar to those in the first embodiment. Note that the LT radiator F202 is an example of a "heat dissipation device" in the claims.

[0083] (Water Injection Cooling System Configuration) The water injection cooling system 200 of the second embodiment shown in FIG. 3 is configured to promote heat dissipation in an LT radiator F202, which is a device that dissipates heat.

[0084] The fuel cell vehicle VE is equipped with a motor circuit 200F in which a liquid coolant (antifreeze) circulates. The motor circuit 200F includes a motor F201a, an inverter F201b, an LT radiator F202, a water pump F3, and a circular coolant passage F4 through which the liquid coolant flows. The motor F201a is a predetermined drive motor included in the fuel cell vehicle VE. As an example, the motor F201a is a motor that rotates the wheels.

[0085] The motor F201a is provided with an output sensor 201 that detects the rotation speed, which is the output of the motor F201a. The water injection cooling system 200 is configured to adjust the rotation speed of the water pump 12 based on the output of the motor F201a.

[0086] Specifically, in the water injection cooling system 200, when the rotation speed of the motor F201a increases, the temperature of the liquid coolant flowing through the motor F201a and the LT radiator F202 rises, and the need to cool the LT radiator F202 increases, so the water injection cooling system 200 increases the rotation speed of the water pump 12. In other words, the injection amount (injection speed) of the water injected from the injection unit 2 per unit time is increased.

[0087] On the other hand, when the rotation speed of the motor F201a is reduced, the temperature of the liquid coolant flowing through the motor F201a and the LT radiator F202 is lowered, and the need to cool the LT radiator F202 is reduced, so the water injection cooling system 200 reduces the rotation speed of the water pump 12. In other words, the injection amount (injection speed) of the water injected from the injection unit 2 per unit time is reduced. Note that the adjustment of the rotation speed of the water pump by the water injection cooling system may be performed via the control unit.

[0088] The water injection cooling system 200 of the second embodiment includes an injection water storage section 211. The injection water storage section 211 is supplied with and stores drain water discharged from an air conditioner mounted on the fuel cell vehicle VE.

[0089] The jet water supply section 1 is configured to supply drain water discharged from an air conditioner to the heat exchanger 30 (jet water heating section 3) and the jet section 2 as jet water.

[0090] The jet water heating section 3 is configured to heat the jet water before it is jetted from the jet section 2. The ambient temperature raising section 4 is configured to supply high-temperature gas having a temperature higher than the ambient temperature of the jet area 40 to the jet area 40 into which the jet water is jetted by the jet section 2, thereby raising the ambient temperature of the jet area.

[0091] The other configurations of the second embodiment are similar to those of the first embodiment.

[0092] (Effects of the second embodiment) In the second embodiment, the following effects can be obtained.

[0093] As described above, the second embodiment is provided with at least one of the jet water heating section 3 that heats the jet water before it is jetted from the jet unit 2, and the ambient temperature raising section 4 that supplies high-temperature gas having a temperature higher than the ambient temperature of the jet area 40 to the jet area 40 into which the jet water is jetted by the jet unit 2, thereby raising the ambient temperature of the jet area 40. As a result, as in the first embodiment, the temperature of the jet water when it adheres to the LT radiator F202 can be increased, effectively promoting heat dissipation from the LT radiator F202 that utilizes the latent heat of evaporation of the jet water.

[0094] Furthermore, in the second embodiment, as described above, the rotation speed of the water pump 12 that supplies the injection water to the injection unit 2 is adjusted in accordance with the output of the motor F201a detected by the output sensor 201. This makes it possible to inject an appropriate amount of injection water from the injection unit 2 in accordance with the temperature rise of the LT radiator F202 that dissipates heat.

[0095] The other effects of the second embodiment are similar to those of the first embodiment.

[0096] [Variations] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is indicated by the claims, not by the description of the embodiments above, and further includes all modifications (variations) within the meaning and scope of the claims.

[0097] For example, in the above first and second embodiments, the water injection cooling systems 100 and 200 are provided with both the injection water heating unit 3 and the ambient temperature raising unit 4, but the present invention is not limited to this. In the present invention, the water injection cooling system may be provided with only one of the injection water heating unit and the ambient temperature raising unit.

[0098] In the above first embodiment, the water generated by the fuel cell is used as the jet water, and in the above second embodiment, the drain water discharged from the air conditioner is used as the jet water, but the present invention is not limited to this. For example, in the present invention, water refilled into the jet water reservoir by a user may be used as the jet water.

[0099] In the above first and second embodiments, an example was shown in which the ejection unit 2 has four nozzles 20, but the present invention is not limited to this. In the present invention, the ejection unit may have a number of nozzles other than four.

[0100] In the above first and second embodiments, the direction of the water jetted from the nozzle 20 of the jet unit 2 is along the outer surface of the radiator, but the present invention is not limited to this. In the present invention, the direction of the water jetted from the nozzle of the jet unit may be a direction intersecting or perpendicular to the outer surface of the radiator.

[0101] In the above first and second embodiments, the waste heat of the air condenser A is used to increase the ambient temperature of the injection region 40, but the present invention is not limited to this. In the present invention, the ambient temperature of the injection region may be increased by using waste heat from the LT radiator of the motor, etc.

[0102] In the first embodiment, the heat dissipation device of the present invention is configured as a fuel cell radiator, and in the second embodiment, the heat dissipation device of the present invention is configured as an LT radiator, but the present invention is not limited to this. In the present invention, the heat dissipation device may be configured as an air condenser, etc.

[0103] In the above first and second embodiments, an example is shown in which the heat exchanger 30 is configured to exchange heat between the liquid refrigerant and the sprayed water (an example in which the heat exchanger is a liquid-liquid type heat exchanger), but the present invention is not limited to this. In the present invention, the heat exchanger may be a gas-liquid type heat exchanger. In this case, for example, heat exchange can be performed between the exhaust gas discharged from the fuel cell stack and the sprayed water.

[0104] In the above first and second embodiments, the jet water heating section of the present invention is configured by a heat exchanger, but the present invention is not limited to this. In the present invention, the jet water heating section may be configured by a heating section that directly heats the water passage to heat the jet water without using heat exchange. [Explanation of symbols]

[0105] 1 Injection water supply section 2 Injection part 3 Injection water heating section 4 Ambient temperature rise section 30 heat exchanger 40 injection area 100, 200 Water injection cooling system A1 Waste heat source F1 fuel cell stack F2 Fuel cell radiator (heat dissipation device) F20 (Fuel cell radiator) outer surface F202 LT radiator (heat dissipation device) VE Fuel Cell Vehicle

Claims

1. an injection unit that injects water onto an outer surface of the heat dissipation device that dissipates heat; A water injection cooling system comprising at least one of a water injection heating unit that heats the injection water before it is injected from the injection unit, and an ambient temperature raising unit that supplies high-temperature gas having a temperature higher than the ambient temperature of an injection region into which the injection water is injected by the injection unit, thereby raising the ambient temperature of the injection region.

2. The jet water heating unit; a water jet supply unit that supplies the water jet to the jet unit; The heat dissipation device is configured to allow a high-temperature liquid refrigerant to flow therethrough; The water injection cooling system according to claim 1, wherein the injection water heating section includes a heat exchanger provided in the injection water supply section and configured to heat the injection water by exchanging heat between the low-temperature injection water supplied to the injection section and the high-temperature liquid refrigerant.

3. the heat dissipation device is a fuel cell radiator that cools the liquid coolant in the fuel cell stack, The water injection cooling system according to claim 2 , wherein the injection water supply unit is configured to supply water produced in the fuel cell stack to the heat exchanger as the injection water.

4. The atmospheric temperature increasing unit is provided, 2. The water injection cooling system according to claim 1, wherein the ambient temperature increasing unit is configured to supply the high-temperature gas heated by waste heat discharged from a predetermined waste heat source to the injection area to increase the ambient temperature of the injection area.

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