Thermal management system

Abstract

To perform efficient heating.SOLUTION: A thermal management system includes: a first state in which a flow passage 1 for FC cooling is connected to a heater flow passage 2 to thereby allow cooling water to flow into the heater flow passage 2 and inflow of cooling water into a first heat exchanger 18 is blocked; a second state in which the cooling water is allowed to flow into the first heat exchanger 18 and cooling water is allowed to flow into the heater flow passage 2; and a third state in which cooling water is allowed to flow into the first heat exchanger 18 and cooling water is circulated in the heater flow passage 2. When a heating load on a heater core 20 is low, the system is brought into the first state. When a heating load on the heater core 20 is middle, the system is brought into the second state, when the heating load on the heater core 20 is high, the system is brought into the third state.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a thermal management system including a cooling water for a fuel cell and a heat medium for air conditioning. [Background technology]

[0002] A vehicle equipped with a fuel cell has both a cooling system that circulates coolant to cool the fuel cell, and an air conditioning system that circulates a heat medium to a heat pump to cool and heat the vehicle interior. In Patent Document 1, the fuel cell cooling system and the air conditioning system are installed independently, and the two systems are used in either a non-linked state or a linked state. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-181505 Summary of the Invention [Problem to be solved by the invention]

[0004] There is a demand for efficient use of heat from the fuel cell cooling system in the air conditioning system. [Means for solving the problem]

[0005] The thermal management system according to the present disclosure includes: an FC cooling flow path through which coolant for cooling a fuel cell flows; a heater flow path including a water heater connected to the FC cooling flow path and heating the coolant; a heater core that heats air in a vehicle cabin using the coolant as a heat source; and a water temperature sensor that measures the temperature of the coolant flowing into the heater core; a first heat exchanger that performs heat exchange between the coolant from the FC cooling flow path and a heat medium; a compressor that compresses and discharges the heat medium that flows from the first heat exchanger; and a second heat exchanger that exchanges heat between the heat medium that flows out of the compressor and the coolant in the heater flow path. and a switching unit provided on the FC cooling flow path between the fuel cell and the first heat exchanger, the switching unit being switchable between a first state connecting the FC cooling flow path and the heater flow path and allowing the coolant to flow into the heater flow path and blocking the coolant from flowing into the first heat exchanger, a second state allowing the coolant to flow into the first heat exchanger and allowing the coolant to flow into the heater flow path, and a third state allowing the coolant to flow into the first heat exchanger and circulating the coolant in the heater flow path.

[0006] The first state is set when the heating load on the heater core is low, the second state is set when the heating load on the heater core is medium, and the third state is set when the heating load on the heater core is high. [Effects of the Invention]

[0007] By switching between the first, second and third states, efficient heating can be achieved by the heater core using the fuel cell as a heat source. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a block diagram showing the configuration of a thermal management system 100 according to an embodiment, illustrating the flows of coolant and heat medium in a first state. [Figure 2] FIG. 10 is a diagram showing the flows of the coolant and the heat medium in a second state. [Figure 3]FIG. 10 is a diagram showing the flows of the coolant and the heat medium in a third state. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that the following embodiments do not limit the present disclosure, and configurations formed by selectively combining multiple examples are also included in the present disclosure.

[0010] "Overall system configuration" 1 is a block diagram showing the configuration of a thermal management system 100 according to an embodiment, illustrating the flow of a first state. The thermal management system 100 includes an FC cooling flow path 1 that supplies coolant to a fuel cell (FC) 10, a heater flow path 2 that supplies coolant to a heater core 20 that heats the vehicle interior, and a heat exchange flow path 3 that supplies a heat medium to an evaporator 40 that cools the vehicle interior. Note that it is also possible to use liquids or gases other than water as the coolant flowing through the FC cooling flow path. Furthermore, various refrigerants used in air conditioners and the like can be used as the heat medium.

[0011] The FC cooling flow path 1 is a cooling water circulation path that includes a pump (WP) 12, a fuel cell 10, a three-way valve 16 as a switching unit, a first heat exchanger 18, and a radiator 14. Also, a bypass path 1a that bypasses the radiator 14 is provided (a bypass control valve and the like are not shown).

[0012] The heater flow path 2 includes a path that branches off from the three-way valve 16 and connects to the FC cooling flow path 1 upstream of the radiator 14 via a second heat exchanger 22, a water heater 24, and a heater core 20, and a circulation path that connects the outlet side of the heater core 20 to the inlet side of the second heat exchanger 22 via a pump 26 and an adjustment valve 28. A water temperature sensor 30 that measures the temperature of the coolant is installed at the inlet of the heater core 20. The water temperature sensor 30 may be installed at the outlet side of the heater core 20 or inside it.

[0013] A heat exchange flow path 3 through which a heat medium circulates is connected to the first heat exchanger 18 and the second heat exchanger 22. The first heat exchanger 18 exchanges heat between the cooling water in the FC cooling flow path 1 and the heat medium in the heat exchange flow path 3, and the second heat exchanger 22 exchanges heat between the cooling water in the heater flow path 2 and the heat medium in the heat exchange flow path 3.

[0014] The heat medium outlet of the first heat exchanger 18 is connected to the heat medium inlet of the first heat exchanger 18 via the compressor 42, the second heat exchanger 22, and the pressure reducing valve 50. Therefore, heat can be exchanged between the cooling water of the first heat exchanger 18 and the cooling water of the second heat exchanger 22 using the heat medium circulated by the compressor 42. In other words, the first heat exchanger 18, the compressor 42, and the second heat exchanger 22 form a heat pump.

[0015] The outlet of the compressor 42 is connected to the inlet of the compressor 42 via an air-cooled condenser 48, a control valve 56, a pressure-reducing valve 44, the evaporator 40, and a pressure control valve 46. A control valve 52 is disposed in the path between the compressor 42 and the first heat exchanger 18, a control valve 54 is disposed on the outlet side of the second heat exchanger 22, and a control valve 56 is disposed on the outlet side of the air-cooled condenser 48. Therefore, the heat medium can be circulated through the air-cooled condenser 48, the pressure-reducing valve 44, the evaporator 40, and the pressure control valve 46, with heat being dissipated by the air-cooled condenser 48 and absorbed by the evaporator 40 from the air in the vehicle cabin, thereby cooling the vehicle cabin.

[0016] The control unit 60 controls various devices within the system to manage the temperature of the fuel cell 10 and also controls heating and cooling within the vehicle cabin. The control unit 60 is made up of a computer, receives various signals, and outputs control signals.

[0017] "Heating control" Next, we will explain the control state according to the heating load, which is the amount of heat required to heat the vehicle interior. In this state, the vehicle interior is heated, and cooling by the radiator 14 and air conditioning by the evaporator 40 are not required. Therefore, for the radiator 14, the coolant is diverted to the bypass path 1a, and in the heat exchange flow path 3, the heat medium does not need to circulate through the air-cooled condenser 48, the evaporator 40, and the compressor 42.

[0018] "Low heating load (first state)" 1 shows the flow of the coolant and heat medium in the first state, i.e., during heating, a low-load state in which the heating demand is relatively small. The three-way valve 16 supplies the coolant from the fuel cell 10 side to the second heat exchanger side and does not allow the coolant to flow to the first heat exchanger 18 side. Therefore, the coolant from the pump 12 circulates through the fuel cell 10, the three-way valve 16, the second heat exchanger 22, the water heater 24, and the heater core 20. As a result, the coolant, which has received heat from the fuel cell 10 and whose temperature has risen, dissipates heat in the heater core 20.

[0019] In this way, in the first state with a low heating load, heat obtained by cooling the fuel cell 10 is used for room heating by the heater core 20, thereby performing thermal cooperation.

[0020] "Medium heating load (state 2)" FIG. 2 shows the flow of the cooling water and the heat transfer medium in the second state, that is, during heating and in a medium load state where the heating demand is medium.

[0021] The three-way valve 16 allows the coolant to flow not only to the second heat exchanger 22 side (heater flow path 2) but also to the first heat exchanger 18 side. In addition, the compressor 42 is driven to circulate the heat medium through the heat exchange flow paths of the first heat exchanger 18 and the second heat exchanger 22. The heat medium recovers heat from the coolant in the first heat exchanger 18, and heats the coolant in the heater flow path 2 in the second heat exchanger 22. In other words, heat can be transferred in the heat exchange flow path 3 by the heat pump.

[0022] Therefore, the heat generated by the fuel cell 10 can be sufficiently recovered and used for heating without using the radiator 14.

[0023] "Heating high load (state 3)" 3 shows the flow of the coolant and heat medium in the third state, i.e., during heating, a high-load state in which the heating demand is relatively large. The three-way valve 16 does not allow the coolant to flow to the second heat exchanger 22 side (heater flow path 2), but only to the first heat exchanger 18 side. The coolant from the fuel cell 10 passes through the first heat exchanger 18 and then circulates to the fuel cell 10.

[0024] Furthermore, by driving the compressor 42 of the heat exchange passage 3, the cooling water of the heater passage 2 flowing through the second heat exchanger 22 is heated by the heat recovered by the first heat exchanger 18.

[0025] Then, by driving the pump 26 and opening the adjustment valve 28, the coolant is circulated through the second heat exchanger 22, the water heater 24, and the heater core 20. This allows the amount of heat dissipation in the heater core 20 to be sufficiently large. In addition, the water heater 24 is controlled so that the coolant temperature at the outlet of the heater core 20 measured by the water temperature sensor 30 becomes a set value.

[0026] In this way, the amount of heat dissipated in the heater core 20 can be controlled to a predetermined value by using the heat from the fuel cell 10 recovered by the first heat exchanger 18 and the heating by the water heater 24. The amount of coolant circulated to the heater core 20 can be increased by driving the pump 26, and the amount of heating by the water heater 24 can be increased, thereby increasing the heating capacity of the heater core 20.

[0027] In the third state, the three-way valve 16 allows all of the cooling water from the fuel cell 10 to be supplied to the first heat exchanger. Therefore, more heat can be recovered by the first heat exchanger 18 than in the second state, the temperature of the cooling water flowing out of the second heat exchanger 22 is less likely to drop than in the second state, and an increase in power consumption by the water heater 24 can be suppressed.

[0028] The amount of water circulated by the pump 26 can be controlled by the control unit 60 to an appropriate amount depending on the amount of heat received by the second heat exchanger 22, the amount of heat generated by the water heater 24, etc. Furthermore, the flow rate sent by the pump 12 returns via the first heat exchanger 18, and a valve may be provided between the suction side of the pump 26 and the flow path connecting the first heat exchanger 18 and the radiator 14.

[0029] "About switching control" The control unit 60 switches between the first, second and third states using a switching unit including the three-way valve 16 .

[0030] For example, whether the heating load is low or not is determined based on whether the water temperature measured by the water temperature sensor 30 is equal to or lower than a first threshold, and if this determination is YES, the system is placed in state 1. If the water temperature is not equal to or lower than the first threshold, the system is determined to be medium or not, and if this determination is YES, the system is placed in state 2. If the heating load is not medium, the heating load is determined to be high, and the system is placed in state 3.

[0031] Here, the control unit 60 determines the heating load based on the outside air temperature, the vehicle interior air temperature, the heater core inlet and outlet coolant temperatures, and the target temperature set by the user, and controls the heating in the heater core 20.

[0032] That is, the heating load of the heater core 20 is determined according to various factors, the inlet coolant temperature of the heater core 20 is determined according to the heating load, and the heating of the coolant is controlled so that the water temperature at the inlet of the heater core 20 measured by the water temperature sensor 30 becomes a set value. Therefore, the higher the heating load, the higher the inlet water temperature of the heater core 20. Therefore, control according to the heating load can be performed by setting the first state when the water temperature measured by the water temperature sensor 30 is equal to or lower than a first threshold, switching from the first state to the second state when the water temperature is equal to or higher than the first threshold, and switching from the second state to the third state when the water temperature is equal to or higher than a second threshold that is higher than the first threshold.

[0033] The heating load can also be determined based on the difference between the vehicle interior temperature and the user-set temperature. That is, the greater the difference between the outside temperature and the vehicle interior temperature, the higher the heating load can be determined. The greater the difference between the heater core outlet coolant temperature and the vehicle interior temperature, the greater the airflow volume can be.

[0034] "Effects of the embodiment" In this embodiment, the heat recovered by the heat exchange passage 3 for cooling in the first heat exchanger 18 can be used for heating, allowing for efficient heat management and reducing the power consumption of the water heater 24. [Explanation of symbols]

[0035] 1 FC cooling flow path, 1a bypass path, 2 heater flow path, 3 heat exchange flow path, 10 fuel cell, 12, 26 pump, 14 radiator, 16 three-way valve, 18 first heat exchanger, 20 heater core, 22 second heat exchanger, 24 water heater, 28 adjustment valve, 30 water temperature sensor, 40 evaporator, 42 compressor, 44, 50 pressure reducing valve, 46 pressure control valve, 48 air-cooled condenser, 52, 54, 56 control valve, 60 control unit, 100 thermal management system.

Claims

[Claim 1] a FC cooling flow path through which cooling water for cooling the fuel cell flows; connected to the FC cooling flow path, a water heater for heating the cooling water; a heater core that heats the air in the vehicle cabin using the cooling water as a heat source; a water temperature sensor that measures the temperature of the cooling water flowing through the heater core; a heater flow path including: a first heat exchanger for exchanging heat between the cooling water from the FC cooling flow path and a heat medium; a compressor that compresses the heat medium flowing from the first heat exchanger and outputs the compressed heat medium; a second heat exchanger that exchanges heat between the heat medium flowing out of the compressor and the cooling water in the heater flow path; a heat exchange flow path including: provided on the FC cooling flow path between the fuel cell and the first heat exchanger, a first state in which the FC cooling flow path and the heater flow path are connected to allow the cooling water to flow into the heater flow path and block the cooling water from flowing into the first heat exchanger; a second state in which the cooling water is allowed to flow into the first heat exchanger and into the heater flow path; a third state in which the cooling water is allowed to flow into the first heat exchanger and the cooling water is circulated in the heater flow path; a switching unit that can be switched to Including, The first state is set when the heating load on the heater core is low, the second state is set when the heating load on the heater core is medium, and the third state is set when the heating load on the heater core is high. Thermal management system.

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