Vehicle structure

Abstract

To provide a vehicle structure which enables a plurality of heat exchange circuits to be easily arranged in a vehicle.SOLUTION: A vehicle structure includes a plurality of heat exchange circuits in which a heat medium circulates. The plurality of heat exchange circuits include a main circuit and a sub circuit. Further, the vehicle structure includes: a reserve tank connected in series or parallel with the main circuit; and one connection pipe connecting the sub circuit with the reserve tank.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a vehicle structure having a plurality of heat exchange circuits through which a heat medium is circulated. [Background technology]

[0002] Patent Document 1 discloses a cooling system for cooling a heat-generating object mounted on a vehicle. The cooling system disclosed in Patent Document 1 is a heat exchange circuit in which a power control unit (hereinafter referred to as PCU), a radiator, and an electric water pump are connected by hoses. The PCU is a heat-generating object. By circulating a heat medium through the heat exchange circuit using the water pump, the heat medium cooled in the radiator cools the PCU. A reserve tank is connected in series to this cooling system. The reserve tank has the function of separating air bubbles that have entered the heat exchange circuit. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-9338 Summary of the Invention [Problem to be solved by the invention]

[0004] An automobile with an internal combustion engine typically has one heat exchange circuit for cooling the engine. On the other hand, an electric vehicle (EV) such as a hybrid electric vehicle (HEV) or a battery electric vehicle (BEV) has multiple heat exchange circuits. For example, a BEV has a heat exchange circuit for maintaining the temperature of a heater core for heating within a predetermined range, a heat exchange circuit for cooling a PCU, and a heat exchange circuit for maintaining the temperature of a battery within a predetermined range.

[0005] The multiple heat exchange circuits are independent and each has a reserve tank. In this case, the layout of the heat exchange circuits in the vehicle tends to be complicated, which tends to reduce the productivity of the vehicle. Furthermore, in small vehicles, the layout space in the vehicle is limited, so it may be difficult to appropriately position the reserve tank for each heat exchange circuit.

[0006] One object of the present invention is to provide a vehicle structure that makes it easy to arrange a plurality of heat exchange circuits in a vehicle. [Means for solving the problem]

[0007] <1> A vehicle structure according to one aspect of the present invention includes: A vehicle structure including a plurality of heat exchange circuits through which a heat medium is circulated, The plurality of heat exchange circuits include a main circuit and a sub-circuit, a reserve tank connected in series or parallel to the main circuit; A single connecting pipe is provided to connect the sub-circuit and the reserve tank.

[0008] <2> the above <1> In the vehicle structure described in The sub-circuit may include a valve for replenishing the heat medium, the valve being provided in a pipe that forms part of the sub-circuit. [Effects of the Invention]

[0009] the above <1> In the vehicle structure described in the above, the reserve tank is shared by the main circuit and the sub-circuit. The reduced number of reserve tanks makes it easier to arrange the main circuit and the sub-circuit in the limited space in the vehicle. The ease of arranging the main circuit and the sub-circuit improves the productivity of the vehicle. Furthermore, the reduced number of reserve tanks reduces the weight of the vehicle and also reduces the cost of the vehicle.

[0010] the above <1> In the vehicle structure described in [2], the sub-circuit is connected to the reserve tank by a single connecting pipe. Therefore, as shown in the embodiment described below, bubbles generated in the sub-circuit tend to move to the reserve tank, but the heat medium in the sub-circuit does not tend to move to the reserve tank. Therefore, the heat medium in the main circuit and the heat medium in the sub-circuit do not mix uniformly. Even if the required heat medium temperatures in the main circuit and the sub-circuit are different, the main circuit and the sub-circuit can share the reserve tank.

[0011] the above <2> The heat transfer medium replenishment valve provided in the vehicle structure described in is used when replenishing the heat transfer medium from the reserve tank to the heat exchange circuit. When replenishing the heat transfer medium, a hose is added that connects the heat transfer medium replenishment valve to the reserve tank, and the heat transfer medium is circulated in the sub-circuit, so that air bubbles that have become mixed in the sub-circuit can be sent to the reserve tank. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a schematic diagram of a vehicle structure according to an embodiment. [Figure 2] FIG. 2 is a schematic diagram of the vicinity of the reserve tank in the vehicle structure shown in FIG. [Figure 3] FIG. 3 is an explanatory diagram illustrating a procedure for replenishing the heat medium in the vehicle structure shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0013] An example of an embodiment of a vehicle structure according to the present invention will now be described with reference to the drawings. The dimensions of components shown in the drawings are for the purpose of clarity of explanation and do not necessarily represent actual dimensions. The present invention is not limited to the following examples, but is defined by the claims, and includes all modifications within the meaning and scope of the claims.

[0014] <Embodiment 1> FIG. 1 shows an example of a vehicle structure 1 including a plurality of heat exchange circuits 11, 12 through which a heat medium 6 is circulated. The heat exchange circuits 11, 12 include a heat source, a heat exchanger, and a pump that circulates the heat medium. FIG. 1 shows only the heat exchange circuits 11, 12, and does not show other components of the vehicle. The vehicle in this example is an EV. EVs include HEVs, BEVs, and FCEVs. HEVs also include plug-in hybrid vehicles and series hybrid vehicles. FCEVs are hydrogen vehicles equipped with fuel cells that generate electricity from hydrogen.

[0015] In this example, the heat exchange circuit 11 is a main circuit 2 that maintains the temperature of the electric unit 20 of the EV within a predetermined range. On the other hand, the heat exchange circuit 12 is a sub-circuit 3 that maintains the temperature of the heater core 31 of the air conditioner within a predetermined range. There may be multiple sub-circuits 3. In addition to the electric unit 20, HEVs and BEVs are provided with a heat exchange circuit that maintains the temperature of a battery (not shown) within a predetermined range. The heat exchange circuit related to the battery can be either the main circuit 2 or the sub-circuit 3.

[0016] The main circuit 2 is a heat exchange circuit with a larger thermal load than the sub-circuit 3. In other words, the sub-circuit 3 is a heat exchange circuit with a smaller thermal load than the main circuit 2. The thermal load is the amount of heat exchanged per unit time in the heat exchangers provided in the heat exchange circuits 11 and 12. In the main circuit 2, it is the amount of heat radiated per unit time in the radiator 21, which is a heat exchanger, and in the sub-circuit 3, it is the amount of heat radiated per unit time in the heater core 31, which is a heat exchanger.

[0017] A heat exchange circuit with a large thermal load has a large flow rate of the heat medium 6. The flow rate of the heat medium 6 is the amount of heat medium 6 discharged from a pump that circulates the heat medium 6. In other words, which of the heat exchange circuits 11 and 12 is the main circuit 2 can be determined by the magnitude of the flow rate of the heat medium 6 flowing through the heat exchange circuits 11 and 12.

[0018] The vehicle structure 1 of this example includes the above-mentioned main circuit 2 and sub-circuit 3, and further includes a reserve tank 4 and a connecting pipe 5. Each component of the vehicle structure 1 of this example will be described in detail below.

[0019] <Main circuit> The main circuit 2 of this example maintains the temperature of the electric unit 20 of the EV within a predetermined range by the heat transfer medium 6. The heat transfer medium 6 in the main circuit 2 of this example is liquid. The heat transfer medium 6 is, for example, water or antifreeze. In the main circuit 2 of this example, the heat transfer medium 6 functions as a refrigerant.

[0020] The main circuit 2 of this example includes an electric unit 20, a radiator 21, a first pump 22, and pipes 25, 26, and 27. The pipe 25 connects the electric unit 20, which is a heat source, to the radiator 21, which is a heat exchanger. The pipe 26 connects the radiator 21 and the first pump 22. The pipe 27 connects the first pump 22 and the electric unit 20. In FIG. 1 , the flow direction of the heat medium 6 in the main circuit 2 is indicated by a counterclockwise white arrow.

[0021] The electric unit 20 is a general term for drivetrain members that drive the vehicle. The electric unit 20 includes a motor that drives the vehicle, an inverter that supplies power from a battery (not shown) to the motor, and the like. The electric unit 20 is a heat source and is cooled by a heat medium 6. The temperature of the heat medium 6 introduced into the electric unit 20 to cool it, i.e., the temperature of the heat medium 6 in the pipe 27, is, for example, 65°C or lower.

[0022] The radiator 21 is a heat exchanger that cools the heat medium 6 by radiating heat from the heat medium 6 to the outside of the vehicle. The radiator 21 has a known configuration. For example, the radiator 21 includes a main body 21B having a plurality of fins, an upper tank 21U disposed on top of the main body 21B, and a lower tank 21L disposed on the bottom of the main body 21B. Although not shown, the radiator 21 may further include a fan that blows air into the main body 21B. A pipe 25 is connected to the upper tank 21U. Therefore, the heat medium 6 that has received heat from the electric unit 20 flows into the upper tank 21U. The heat of the heat medium 6 is radiated in the main body 21B. The heat medium 6 cooled in the main body 21B flows into the lower tank 21L and is sent to the first pump 22 through a pipe 26.

[0023] The first pump 22 has a known configuration. For example, the first pump 22 may be a centrifugal pump or an impeller pump. The first pump 22 pumps the heat medium 6 cooled by the radiator 21 toward the electric unit 20.

[0024] The electric unit 20 generates a large amount of heat. Therefore, the thermal load in the main circuit 2 required to maintain the temperature of the electric unit 20 within a predetermined range, i.e., the amount of heat dissipated by the heat transfer medium 6 in the radiator 21, is large. In such a main circuit 2, the flow rate of the heat transfer medium 6 is increased to ensure the amount of heat dissipated in the radiator 21. When the flow rate of the main circuit 2 increases, a pressure difference is likely to occur within the main circuit 2, which can easily cause cavitation, in which air bubbles are generated in the heat transfer medium 6.

[0025] <Sub-circuit> The subcircuit 3 of this example maintains the temperature of the heater core 31 for heating the EV within a predetermined range. The heat transfer medium 6 in the subcircuit 3 of this example is the same as the heat transfer medium 6 in the main circuit 2 because it is shared with the main circuit 2. The heat transfer medium 6 in the subcircuit 3 of this example functions as a heat transfer medium. In FIG. 1, the flow direction of the heat transfer medium 6 in the subcircuit 3 is indicated by a clockwise white arrow.

[0026] In this example, the subcircuit 3 includes a high-voltage heater 30, a heater core 31, a second pump 32, and pipes 35, 36, 37, and 38. Pipe 35 connects the high-voltage heater 30, which is a heat source, to the heater core 31, which is a heat exchanger. In this example, pipe 35 is provided with a valve 33 (hereinafter simply referred to as valve 33) for replenishing the heat medium. The purpose of valve 33 will be described later. Pipes 36 and 37 connect the heater core 31 and the second pump 32. In this example, pipes 36 and 37 are connected by a branch pipe 50. This branch pipe 50 is also connected to a connecting pipe 5, which will be described later. Pipe 38 connects the second pump 32 and the high-voltage heater 30.

[0027] The high-voltage heater 30 is a heat source that increases the temperature of the heat medium 6. The high-voltage heater 30 has a known configuration. For example, a pipe (not shown) through which the heat medium 6 flows is arranged inside the high-voltage heater 30, and the temperature of the heat medium 6 in the pipe increases when the pipe is heated to a high temperature by electricity.

[0028] The heater core 31 is configured to heat the air introduced into the vehicle compartment using the heat medium 6. In other words, the heater core 31 is a heat exchanger that dissipates heat from the heat medium 6 to the air. The heater core 31 has a known configuration. For example, a pipe (not shown) through which the heat medium 6 flows is arranged inside the heater core 31. The heater core 31 is maintained at a predetermined temperature range by the heat medium 6. The air introduced into the vehicle compartment is heated by passing through the heater core 31. As a result, the temperature of the vehicle compartment rises. The temperature of the heat medium 6 introduced into the heater core 31, i.e., the temperature of the heat medium 6 in the pipe 37, is, for example, 80°C or less.

[0029] The second pump 32 has a known configuration. For example, the second pump 32 may be a centrifugal pump or an impeller pump. The second pump 32 pumps the heat medium 6 from the high-voltage heater 30 through a pipe 35 toward the heater core 31. The output of the second pump 32 is smaller than the output of the first pump 22.

[0030] The sub-circuit 3 is designed to maintain the temperature of the heater core 31 within a predetermined range. Therefore, the thermal load of the sub-circuit 3, i.e., the amount of heat of the heat transfer medium 6 radiated by the heater core 31, is smaller than the amount of heat of the heat transfer medium 6 radiated by the radiator 21 of the main circuit 2. In this sub-circuit 3, the flow rate of the heat transfer medium 6 required to maintain the temperature of the heater core 31 may be small. As long as the temperature of the heater core 31 is maintained within the predetermined range, heating by the high-voltage heater 30 may be stopped, and the circulation of the heat transfer medium 6 may be stopped. Cavitation is less likely to occur in the sub-circuit 3, where the flow rate of the heat transfer medium 6 is small. In other words, bubbles are less likely to occur in the sub-circuit 3.

[0031] <Reserve Tank> The reserve tank 4 is shared by the main circuit 2 and the sub-circuit 3. In other words, there is only one reserve tank 4 provided for the main circuit 2 and the sub-circuit 3. The reserve tank 4 is used when refilling the main circuit 2 and the sub-circuit 3 with the heat medium 6. The reserve tank 4 also has the function of separating air bubbles mixed into the heat medium 6. A liquid phase and a gas phase are formed inside the reserve tank 4. The reserve tank 4 is equipped with a pressure regulating valve 40 connected to the gas phase. The pressure regulating valve 40 is configured to release the gas phase air to the outside of the reserve tank 4 when the pressure of the gas phase reaches or exceeds a certain level.

[0032] The reserve tank 4 is positioned to separate air bubbles mixed in the heat transfer medium 6, making it easy to separate air bubbles in the main circuit 2, where cavitation is likely to occur. Paradoxically, the heat exchange circuit 11 to which the reserve tank 4 is connected, forming a circulation path for the heat transfer medium 6 including the reserve tank 4, can be considered the main circuit 2. In this example, the reserve tank 4 is connected in parallel to the main circuit 2 by pipes 28 and 29. In this example, the pipe 28 connects the upper tank 21U of the radiator 21 to the reserve tank 4. A portion of the heat transfer medium 6 that flows from the pipe 25 into the upper tank 21U is introduced into the reserve tank 4, as indicated by the left-pointing white arrow. Meanwhile, in this example, the pipe 29 connects the reserve tank 4 to the pipe 26. Therefore, a portion of the heat transfer medium 6 stored in the reserve tank 4 is returned to the main circuit 2 through the pipe 29, as indicated by the downward-pointing white arrow.

[0033] As described above, by sharing the reserve tank 4 between the main circuit 2 and the sub-circuit 3, it is easy to arrange the main circuit 2 and the sub-circuit 3 in the limited space in the vehicle. The ease of arranging the main circuit 2 and the sub-circuit 3 improves the productivity of the vehicle. Furthermore, the reduction in the reserve tank 4 reduces the weight of the vehicle and also reduces the cost of the vehicle.

[0034] Unlike this example, the reserve tank 4 may be connected in series to the main circuit 2. In that case, the reserve tank 4 may be disposed, for example, in the middle of the pipe 25, in the middle of the pipe 26, or in the middle of the pipe 27.

[0035] <Communication Pipe> The vehicle structure 1 of this example includes a single connecting pipe 5. The connecting pipe 5 connects the sub-circuit 3 and the reserve tank 4. As shown in FIG. 2, the connecting pipe 5 of this example is connected to a branch pipe 50 disposed between the pipe 36 and the pipe 37 of the sub-circuit 3. The branch pipe 50 of this example is T-shaped and includes a horizontal portion 50A and a vertical portion 50B extending vertically downward from the middle of the horizontal portion 50A. The pipe 36 extending from the heater core 31 (FIG. 1) is connected to one end of the horizontal portion 50A, and the connecting pipe 5 is connected to the other end of the horizontal portion 50A. The pipe 37 extending to the second pump 32 is connected to the end of the vertical portion 50B.

[0036] The heat transfer medium 6 that flows from the pipe 36 into the horizontal section 50A of the branch pipe 50 tends to flow into the pipe 37 due to the influence of gravity, but does not easily flow into the connecting pipe 5. Furthermore, because the branch pipe 50 is located below the reserve tank 4, the heat transfer medium 6 in the connecting pipe 5 does not easily flow into the reserve tank 4. This prevents the heat transfer medium 6 in the main circuit 2 and the heat transfer medium 6 in the sub-circuit 3 from being mixed uniformly. Therefore, even if the temperatures of the heat transfer medium 6 required for the main circuit 2 and the sub-circuit 3 are different, the main circuit 2 and the sub-circuit 3 can share the reserve tank 4. On the other hand, air bubbles contained in the liquid heat transfer medium 6 tend to move upward, and as shown by the two-dot chain line, they tend to move through the connecting pipe 5 to the reserve tank 4.

[0037] The end of the connecting pipe 5 that connects to the reserve tank 4 is arranged parallel to the end of the piping 29 that connects to the reserve tank 4. In other words, the orientation of the opening 5a of the connecting pipe 5 in the reserve tank 4 is the same as the orientation of the opening 29a of the piping 29. Here, in this example, the piping 28 extending from the main circuit 2 (FIG. 1) is connected to the side of the reserve tank 4, and the piping 29 extending from the reserve tank 4 to the main circuit 2 is connected to the bottom surface of the reserve tank 4. Furthermore, the opening 29a of the piping 29 is arranged closer to the piping 28 than the opening 5a of the connecting pipe 5. Therefore, the heat medium 6 that flows into the reserve tank 4 through the piping 28 easily flows toward the opening 29a of the piping 29, as indicated by the white arrow. Because the flow direction of the heat medium 6 at the opening 5a of the connecting pipe 5 is upward, the heat medium 6 that flows from the connecting pipe 5 into the reserve tank 4 is unlikely to be caught in the flow of the heat medium 6 indicated by the white arrow. If the opening 5a of the connecting pipe 5 were facing right in the drawing, the heat transfer medium 6 flowing from the connecting pipe 5 into the reserve tank 4 would be caught up in the flow of the heat transfer medium 6 indicated by the white arrow, and the heat transfer medium 6 would be sucked out of the connecting pipe 5. In that case, the heat transfer medium 6 in the sub-circuit 3 would actively flow into the main circuit 2, and the temperature of the heat transfer medium 6 in the main circuit 2 would fall outside the desired temperature range.

[0038] <Refilling the reserve tank with heat transfer medium> The procedure for replenishing the heat medium 6 to the main circuit 2 and the sub-circuit 3 in the vehicle structure 1 of this example will be described with reference to Fig. 3. Fig. 3 mainly illustrates the sub-circuit 3 and the reserve tank 4.

[0039] When refilling the reserve tank 4 with the heating medium 6, the lid of the reserve tank 4 is opened and the heating medium 6 is poured into the reserve tank 4. At this time, air bubbles are mixed into the heating medium 6 in the reserve tank 4. If these air bubbles remain in the main circuit 2 and the sub-circuit 3, they will hinder the cooling of the electric unit 20 and the heat retention of the heater core 31. Because the reserve tank 4 is connected in parallel to the main circuit 2 shown in FIG. 1, simply operating the first pump 22 and circulating the heating medium 6 through the main circuit 2 can expel the air bubbles in the main circuit 2 into the reserve tank 4. On the other hand, because the sub-circuit 3 is connected to the reserve tank 4 only by the connecting pipe 5, it takes time to remove the air bubbles from the sub-circuit 3.

[0040] The vehicle structure 1 of this example includes a valve 33 provided in the pipe 35 as a component for efficiently removing air bubbles from the sub-circuit 3. To remove air bubbles from the sub-circuit 3, the valve 33 in the pipe 35 is opened, and the valve 33 is connected to the reserve tank 4 by a hose 7. In this state, the second pump 32 is operated to circulate the heat medium 6 in the sub-circuit 3. At the same time, the heat medium 6 is also circulated in the main circuit 2. The thin arrows in FIG. 3 indicate the flow of the heat medium 6 in the sub-circuit 3. The hose 7 forms a flow path that actively flows the heat medium 6 from the sub-circuit 3 to the reserve tank 4, so that air bubbles that have entered the sub-circuit 3 are sent to the reserve tank 4. The air bubbles are separated from the heat medium 6 in the reserve tank 4. When the air bubbles are removed, the water level of the heat medium 6 in the reserve tank 4 drops, so additional heat medium 6 is added to circulate the heat medium 6 again. The addition of the heat transfer medium 6 and the circulation of the heat transfer medium 6 are repeated until the water level in the reserve tank 4 stops dropping, thereby completing the replenishment of the heat transfer medium 6.

[0041] The end of the hose 7 that is placed in the reserve tank 4 is preferably placed in the heat medium 6. By placing the end of the hose 7 in the heat medium 6, air bubbles are less likely to be generated when the heat medium 6 flows from the hose 7 into the reserve tank 4. [Explanation of symbols]

[0042] 1 Vehicle structure 11,12 Heat exchange circuit 2 Main Circuit 20 Electric unit 21 Radiator, 21B Body, 21L Lower Tank, 21U Upper Tank 22 First Pump 25,26,27,28,29 Piping, 29a opening 3 Subcircuits 30 high voltage heater, 31 heater core, 32 second pump 33 Heat transfer medium replenishment valve 35, 36, 37, 38 Piping 4 reserve tank 40 Pressure Regulating Valve 5. Connecting pipe 5a aperture 50 branch pipe, 50A horizontal section, 50B vertical section 6 Heat medium 7 Hose

Claims

[Claim 1] A vehicle structure including a plurality of heat exchange circuits through which a heat medium is circulated, The plurality of heat exchange circuits include a main circuit and a sub-circuit, a reserve tank connected in series or parallel to the main circuit; a single connecting pipe connecting the sub-circuit and the reserve tank; a first pipe that introduces a portion of the heat medium in the main circuit into the reserve tank; a second pipe that returns a portion of the heat medium in the reserve tank to the main circuit, an opening of the connecting pipe in the reserve tank and an opening of the second pipe are disposed in a lower portion of the reserve tank and face upward; the opening of the second pipe is disposed at a position closer to the opening of the first pipe in the reserve tank than the opening of the connecting pipe, the sub-circuit includes a valve provided in a pipe that forms part of the sub-circuit; The valve is configured to be connectable to a hose that allows the heat medium to flow from the valve to the reserve tank. Vehicle structure.

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