Cooling system

Abstract

To suppress heating quantity from moving between a first system and a second system in a cooling system including two systems of coolant flow paths and a reserve tank.SOLUTION: A cooling system includes a first-system flow path, a second-system flow path, and a reserve tank. The reserve tank includes: a first chamber; a second chamber disposed at a same height as the first chamber or at a lower height than the first chamber; a third chamber and a fourth chamber that are disposed at a lower position than the first chamber; and an intermediate chamber. The first chamber opens to a first inlet; the second chamber opens to a first outlet; the third chamber opens to a second inlet; and the fourth chamber opens to a second outlet. The first chamber communicates with the second chamber; the third chamber communicates with the fourth chamber; and the first chamber communicates with the third chamber via the intermediate chamber. The first-system flow path is connected to the first inlet and first outlet; and the second-system flow path is connected to the second inlet and the second outlet.SELECTED DRAWING: Figure 3

Description

Technical Field

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[0005]

[0001] The technology disclosed in this specification relates to a cooling system having a first system flow path for cooling a first heating element and a second system flow path for cooling a second heating element.

Background Art

[0002] A cooling device using a liquid refrigerant includes a reserve tank. In the reserve tank disclosed in Patent Document 1, the refrigerant flows in from the outside. After staying in the reserve tank, the refrigerant flows out of the reserve tank. While the refrigerant is staying in the reserve tank, air bubbles are removed from the refrigerant.

[0003] The cooling systems disclosed in Patent Documents 2 and 3 have two systems of refrigerant flow paths, and the two systems of refrigerant flow paths share one reserve tank. In Patent Document 2, a reserve tank that suppresses heat transfer between the first system and the second system has been proposed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0005] This specification provides a technique for suppressing heat transfer between a first system flow path and a second system flow path in a cooling system including two systems of refrigerant flow paths and a reserve tank common to them, more than the technique of Patent Document 2.

Means for Solving the Problems

[0006] The cooling system disclosed herein comprises a first channel, a second channel, and a reserve tank. The first channel cools a first heat-generating element. The second channel cools a second heat-generating element that is at a lower temperature than the first heat-generating element.

[0007] The reserve tank comprises a first chamber, a second chamber, a third chamber, and a fourth chamber, all facing the outer wall of the reserve tank. The second chamber is located at the same height as the first chamber or lower. The third and fourth chambers are located lower than the first chamber. The reserve tank further comprises at least one intermediate chamber and a first inlet, a first outlet, a second inlet, and a second outlet, all located on the outer wall of the reserve tank. The first inlet opens into the first chamber, and the first outlet opens into the second chamber. The second inlet opens into the third chamber, and the second outlet opens into the fourth chamber. The first and second chambers are in communication with each other, and the third and fourth chambers are in communication with each other. The first chamber is in communication with the third chamber via the intermediate chamber.

[0008] The first system flow path is connected to the first inlet and first outlet, and the second system flow path is connected to the second inlet and second outlet. The refrigerant flowing through the first system flow path cools the first heat-generating element, which is at a higher temperature, so its temperature is higher than the refrigerant flowing through the second system flow path. The higher-temperature refrigerant flows into the first chamber, and the lower-temperature refrigerant flows into the third chamber. The first chamber is located at a higher position than the third chamber, and the first and third chambers are connected by at least one intermediate chamber. Therefore, the refrigerant in the first chamber (higher temperature refrigerant) has difficulty moving to the third chamber, and the refrigerant in the third chamber (lower temperature refrigerant) has difficulty moving to the first chamber. In other words, the transfer of heat between the first and second systems is suppressed.

[0009] The first system flow path may include a first upper flow path connected to a first outlet and a first lower flow path connected to a first inlet. The second system flow path may include a second upper flow path connected to a second outlet and a second lower flow path connected to a second inlet. The cooling system may further include a first pump for supplying refrigerant from a reserve tank to the first upper flow path, a second pump for supplying refrigerant from the reserve tank to the second upper flow path, and a switching valve. The switching valve can switch between a first state in which the first upper flow path is connected to the first lower flow path and the second upper flow path is connected to the second lower flow path, and a second state in which the first upper flow path is connected to the second lower flow path and the first lower flow path and the second upper flow path are closed. In the first state, there is little heat transfer between the first system flow path and the second system flow path, and in the second state, the first system flow path and the second system flow path are combined and can be used as a third system flow path.

[0010] Details of the technology disclosed herein and further improvements are described in the following "Modes for Carrying Out the Invention". [Brief explanation of the drawing]

[0011] [Figure 1] This is a block diagram of the cooling system of the embodiment (first state). [Figure 2] This is a block diagram of the cooling system of the embodiment (second state). [Figure 3] This is a cross-sectional view of the reserve tank of the cooling system in the embodiment. [Figure 4] This is a side view of a modified reserve tank. [Figure 5] This is a top view of the modified reserve tank. [Figure 6] This is a cross-sectional view along the line VI-VI in Figure 5. [Figure 7] This is a cross-sectional view along line VII-VII in Figure 4. [Figure 8] This is a cross-sectional view along the line VIII-VIII in Figure 5. [Figure 9] This is a cross-sectional view along the line IX-IX in Figure 4. [Modes for carrying out the invention]

[0012] The cooling system 2 of the embodiment will be described with reference to the drawings. Figure 1 shows a block diagram of the cooling system 2. The cooling system 2 comprises a first channel 10, a second channel 20, a switching valve 30, and a reserve tank 100. The first channel 10 passes through the first heat-generating element 91. The refrigerant flowing through the first channel 10 cools the first heat-generating element 91. The second channel 20 passes through the second heat-generating element 92. The refrigerant flowing through the second channel 20 cools the second heat-generating element 92. The refrigerant is a liquid, typically water.

[0013] The cooling system 2 is installed in an electric vehicle, and the first heat-generating element 91 is a motor for driving or a power converter that generates AC power to drive the motor. The second heat-generating element 92 is a battery. The amount of heat generated by the first heat-generating element 91 is greater than the amount of heat generated by the second heat-generating element 92. Therefore, the temperature of the refrigerant that has passed through the first system flow path 10 is higher than the temperature of the refrigerant that has passed through the second system flow path 20.

[0014] The first system flow path 10 includes a first upper flow path 11 and a first lower flow path 12. One end (upstream end) of the first upper flow path 11 is connected to the first outlet 102 of the reserve tank 100, and the other end (downstream end) is connected to the switching valve 30. One end (upstream end) of the first lower flow path 12 is connected to the switching valve 30, and the other end (downstream end) is connected to the first inlet 101 of the reserve tank 100. The first system flow path 10 is equipped with a first pump 13. The first pump 13 draws refrigerant from the reserve tank 100 and flows it into the first upper flow path 11. The drawn-up refrigerant passes through the first heating element 91, the switching valve 30, and the first lower flow path 12 and returns to the reserve tank 100.

[0015] The second system flow path 20 includes a second upstream path 21 and a second downstream path 22. One end (upstream end) of the second upstream path 21 is connected to the second outlet 104 of the reserve tank 100, and the other end (downstream end) is connected to the switching valve 30. One end (upstream end) of the second downstream path 22 is connected to the switching valve 30, and the other end (downstream end) is connected to the second inlet 103 of the reserve tank 100. The second system flow path 20 is provided with a second pump 23. The second pump 23 sucks up the refrigerant from the reserve tank 100 and flows it into the second upstream path 21. The sucked-up refrigerant passes through the second heating element 92, the switching valve 30, and the second downstream path 22 and returns to the reserve tank 100.

[0016] Note that the first system flow path 10 and the second system flow path 20 are provided with devices such as a radiator, but their illustration and description are omitted.

[0017] The switching valve 30 can switch between a first state and a second state. FIG. 1 shows the first state. In the first state, the switching valve 30 connects the first upstream path 11 to the first downstream path 12 and connects the second upstream path 21 to the second downstream path 22. In the first state, the first system flow path 10 and the second system flow path 20 share the reserve tank 100, but each becomes an independent cooling circuit.

[0018] FIG. 2 shows the flow path when the switching valve 30 is in the second state. In the second state, the switching valve 30 connects the first upstream path 11 to the second downstream path 22 and closes the first downstream path 12 and the second upstream path 21. When the first pump 13 is driven when the switching valve 30 is in the second state, the refrigerant passes through the reserve tank 100, the first upstream path 11, the switching valve 30, and the second downstream path 22 and returns to the reserve tank 100. In the second state, the first system flow path 10 and the second system flow path 20 merge to form a third system flow path. The third system flow path is utilized under specific conditions.

[0019] FIG. 3 shows a cross-sectional view of the reserve tank 100. In the coordinate system of FIG. 3, the +Z direction corresponds to vertically upward.

[0020] The internal space of the reserve tank 100 is divided into a first chamber 111, a second chamber 112, a third chamber 113, and a fourth chamber 114, which face (are adjacent to) the outer wall 199, and several intermediate chambers 131-139. Adjacent chambers are separated by partition walls, but some of the partition walls are provided with communication holes 140. The second chamber 112 is located at the same height as the first chamber 111. The third chamber 113 and the fourth chamber 114 are located at a lower position than the first chamber 111.

[0021] The liquid level 40a of the refrigerant 40 is located in the intermediate chambers 132, 133, and 134. Above the liquid level 40a is an air layer, and the bubbles contained in the refrigerant 40 move into the air layer and are separated from the refrigerant 40. In other words, the reserve tank 100 has the role of separating the bubbles contained in the refrigerant 40 from the refrigerant 40.

[0022] The outer wall 199 is provided with a first inlet 101, a first outlet 102, a second inlet 103, and a second outlet 104. The first inlet 101 opens into the first chamber 111. The first outlet 102 opens into the second chamber 112. The second inlet 103 opens into the third chamber 113. The second outlet 104 opens into the fourth chamber 114. As previously mentioned, the first inlet 101 is connected to the first downstream channel 12, and the first outlet 102 is connected to the first upstream channel 11. The second inlet 103 is connected to the second downstream channel 22, and the second outlet 104 is connected to the second upstream channel 21.

[0023] Furthermore, the first chamber 111 is connected to the adjacent intermediate chamber 135, and the intermediate chamber 135 is connected to the adjacent second chamber 112. In other words, there is horizontal communication from the first inlet 101 to the first outlet 102. As mentioned earlier, when the switching valve 30 is in the first state, the refrigerant that exits from the first outlet 102 of the reserve tank 100 passes through the first system flow path 10, through the first inlet 101, and returns to the reserve tank 100. The thick arrow A in Figure 3 shows the flow of refrigerant from the first inlet 101 to the first outlet 102. The thick arrow A shows the flow of refrigerant within the reserve tank 100 flowing through the first system flow path 10.

[0024] Meanwhile, the third chamber 113 is in communication with the adjacent fourth chamber 114. When the switching valve 30 is in the first state, the refrigerant that exits from the second outlet 104 of the reserve tank 100 passes through the second system flow path 20 and returns to the reserve tank 100 via the second inlet 103. The thick arrow line B in Figure 3 shows the flow of refrigerant from the second inlet 103 to the second outlet 104. The thick arrow line B also shows the flow of refrigerant within the reserve tank 100 through the second system flow path 20.

[0025] The first chamber 111 and the third chamber 113 are not directly connected, but are connected via intermediate chambers 135 and 137 and the fourth chamber 114. Moreover, the first chamber 111 and the second chamber 112 are located at a higher position than the third chamber 113 and the fourth chamber 114. In other words, the first inlet 101 and the first outlet 102 are located at a higher position than the second inlet 103 and the second outlet 104.

[0026] As mentioned earlier, the first heat-generating element 91, cooled by the refrigerant passing through the first system flow path 10, has a greater heat output than the second heat-generating element 92, cooled by the refrigerant passing through the second system flow path 20. Therefore, the temperature of the refrigerant returning to the first chamber 111 after passing through the first system flow path 10 is higher than the temperature of the refrigerant returning to the third chamber 113 after passing through the second system flow path 20. Refrigerant at a higher temperature has a lower specific gravity than refrigerant at a lower temperature. Therefore, the refrigerant in the first chamber 111, which is located at a higher position (higher temperature refrigerant), has difficulty flowing to the third chamber 113, which is located at a lower position, and the refrigerant in the third chamber 113, which is difficult to flow to the first chamber 111. Heat transfer between the first and second systems is suppressed.

[0027] The fact that the first room 111 and the third room 113 are not directly connected, but are connected via intermediate rooms 135 and 137, also contributes to suppressing the transfer of heat between the first and second systems.

[0028] Furthermore, the shortest path connecting the first inlet 101 to the first outlet 102 (i.e., thick arrow line A) passes at a lower position than the shortest path connecting the second inlet 103 to the second outlet 104 (i.e., thick arrow line B). This also contributes to reducing the amount of heat transferred between the first and second systems.

[0029] When the switching valve 30 is in the second state, the refrigerant in the reserve tank 100 returns to the reserve tank 100 via the first outlet 102, the first upper flow path 11, the second lower flow path 22, and the second inlet 103. The dashed arrow line C in Figure 3 shows the flow of refrigerant in the reserve tank 100 at this time.

[0030] (Modified Version) The structure of the modified reserve tank 200 will be explained with reference to Figures 4-9. Figure 4 is a side view of the reserve tank 200, and Figure 5 is a top view of the reserve tank 200. In Figures 4-9, the +Z direction corresponds to the vertically upward direction.

[0031] The outer wall 299 of the reserve tank 200 is provided with a first inlet 201, a first outlet 202, a second inlet 203, and a second outlet 204. Although the second inlet 203 is not visible in Figures 4 and 5, it is located at the same height as the second outlet 204. The first outlet 202, second inlet 203, and second outlet 204 are located at a lower position than the first inlet 201.

[0032] Figure 6 shows a cross-section along the line VI-VI in Figure 5, and Figure 7 shows a cross-section along the line VII-VII in Figure 4. As shown in Figure 6, the inside of the reserve tank 200 has a three-layer structure, with the second chamber 212, third chamber 213, and fourth chamber 214 located in the lower layer. Note that the third chamber 213 also serves as the fourth chamber 214.

[0033] Intermediate chambers 232, 233, and 234 are located on the upper level, and the first chamber 211 and intermediate chamber 231 are located on the middle level. The first inlet 201 opens into the first chamber 211, and the first outlet 202 opens into the second chamber 212. The second inlet 203 opens into the third chamber 213, and the second outlet 204 opens into the fourth chamber 214.

[0034] Of the first inlet 201, first outlet 202, second inlet 203, and second outlet 204, only the first inlet 201 is positioned higher than the other outlets (first outlet 202, second inlet 203, and second outlet 204). The first outlet 202, second inlet 203, and second outlet 204 are positioned at the same height (lower level).

[0035] The liquid level 40a of the refrigerant 40 is located in the upper layer, i.e., in the intermediate chambers 232, 233, and 234. Bubbles in the refrigerant 40 are released into the intermediate chambers 232, 233, and 234.

[0036] The second inlet 203 is connected to the second lower channel 22 of the second system flow path 20, and the second outlet 204 is connected to the second upper channel 21. When the second pump 23 (see Figure 1) is driven, refrigerant is drawn up from the reserve tank 200 to the second upper channel 21. The refrigerant returns to the reserve tank 200 from the second upper channel 21 through the switching valve 30 and the second lower channel 22. The refrigerant that enters from the second inlet 203 passes through the third chamber 213 (i.e., the fourth chamber 214) and exits from the second outlet 204. The thick arrow line B in Figures 6 and 7 shows the flow of refrigerant from the second inlet 203 to the second outlet 204. The thick arrow line B shows the flow of refrigerant in the second system flow path 20 within the reserve tank 200. The refrigerant in the second system flow path 20 flows in the lowest layer within the reserve tank 200.

[0037] Figure 8 shows a cross-section along line VIII-VIII in Figure 5, and Figure 9 shows a cross-section along line IX-IX in Figure 4. The first inlet 201 opens into the first chamber 211, and the intermediate chamber 231 is adjacent to the first chamber 211. A communication hole 240 is provided in the partition wall between the first chamber 211 and the intermediate chamber 231, and the first chamber 211 and the intermediate chamber 231 are in communication. The second chamber 212 is located below the intermediate chamber 231, and a communication hole 240 is also provided in the partition wall between the intermediate chamber 231 and the second chamber 212. The first chamber 211 is in communication with the second chamber 212 via the intermediate chamber 231. The first outlet 202 opens into the second chamber 212.

[0038] When the first pump 13 (see Figure 1) is driven, refrigerant is drawn up from the reserve tank 200 to the first upper flow path 11. The refrigerant returns to the reserve tank 200 from the first upper flow path 11 through the switching valve 30 and the first lower flow path 12. The refrigerant that enters from the first inlet 201 passes through the first chamber 211, the intermediate chamber 231, and the second chamber 212, and exits from the first outlet 202. The thick arrow line A in Figures 8 and 9 shows the flow of refrigerant from the first inlet 201 to the first outlet 202. The thick arrow line A shows the flow of refrigerant in the reserve tank 200 as it flows through the first system flow path 10. The refrigerant in the first system flow path 10 moves from the intermediate layer to the bottom layer in the reserve tank 200.

[0039] The first chamber 211 is located above the third chamber 213, and there are no connecting holes in the partition wall separating the first chamber 211 and the third chamber 213. Connecting holes 240 are also provided in the partition wall between the second chamber 212 and the third chamber 213. The first chamber 211 and the third chamber 213 are connected via the intermediate chamber 231 and the second chamber 212. In the modified reserve tank 200, as in the reserve tank 100, the transfer of heat between the first and second systems is suppressed.

[0040] The following points should be noted regarding the technology described in the examples. The second chamber may be located at the same height as the first chamber or at a lower position than the first chamber. The third and fourth chambers are located at a lower position than the first chamber. The first and second chambers are in communication. The first and second chambers may be adjacent to each other or may be connected via at least one intermediate chamber. The third and fourth chambers are in communication. The third and fourth chambers may be adjacent to each other or may be connected via at least one intermediate chamber. The first and second chambers are always connected via at least one intermediate chamber.

[0041] Although specific examples of the present invention have been described in detail above, these are merely illustrative and do not limit the scope of the claims. The technologies described in the claims include various modifications and changes to the specific examples illustrated above. The technical elements described in this specification or drawings exhibit technical usefulness individually or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Furthermore, the technologies illustrated in this specification or drawings can achieve multiple objectives simultaneously, and achieving even one of these objectives itself constitutes technical usefulness. [Explanation of Symbols]

[0042] 2: Cooling system 10: First system flow path 11: First upper flow path 12: First lower flow path 13: First pump 20: Second system flow path 21: Second upper flow path 22: Second lower flow path 23: Second pump 30: Switching valve 40: Refrigerant 40a: Liquid level 91: First heating element 92: Second heating element 100, 200: Reserve tank 101, 201: First inlet 102, 202: First outlet 103, 203: Second inlet 104, 204: Second outlet 111, 211: First chamber 112, 212: Second chamber 113, 213: Third chamber 114, 214: Fourth chamber 131-139, 231-234: Intermediate chamber 140, 240: Communication holes 199, 299: Exterior walls

Claims

1. A first system flow path for cooling the first heat-generating element, A second cooling channel for a second heating element having a lower temperature than the first heating element, Reserve tank and A refrigerant system equipped with, The aforementioned reserve tank is The first chamber facing the outer wall of the aforementioned reserve tank, A second room facing the aforementioned exterior wall and positioned at the same height as or lower than the first room, A third room facing the aforementioned exterior wall and positioned lower than the first room, A fourth room facing the aforementioned exterior wall and positioned lower than the first room, At least one intermediate chamber, A first inlet is provided in the outer wall and opens into the first chamber, A first outlet is provided in the outer wall and opens into the second chamber, A second inlet is provided in the outer wall and opens into the third chamber, A second outlet is provided in the outer wall and opens into the fourth chamber, It is equipped with, The first and second rooms are connected, The third and fourth rooms are connected, The first chamber is connected to the third chamber via the intermediate chamber. The first system flow path is connected to the first inlet and the first outlet, The second system flow path is connected to the second inlet and the second outlet. Cooling system.

2. The first system flow path is, The first upper channel connected to the first outlet, The first downstream channel connected to the first inlet, It includes, The second channel is, The second upper channel connected to the second outlet, The second downstream channel connected to the second inlet, It includes, The cooling system further includes, A first pump that flows refrigerant from the reserve tank to the first upper flow path, A second pump that flows refrigerant from the reserve tank to the second upper flow path, A switching valve that switches between a first state in which the first upper passage is connected to the first lower passage and the second upper passage is connected to the second lower passage, and a second state in which the first upper passage is connected to the second lower passage and the first lower passage and the second upper passage are closed, The cooling system according to claim 1, comprising:

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