Control device for a cooling system

Abstract

The present disclosure provides a cooling system control device capable of monitoring the temperature of a heat medium flowing into a second unit based on the temperature of a heat medium flowing out of a first unit in a cooling system in which a heat medium flows through in the order of the first unit and the second unit. A cooling system control device of a cooling system having a cooling path through which a heat medium flows in the order of a first unit and a second unit, and configured to cool the first unit and the second unit. The control device is configured to perform: a process of repeatedly detecting or estimating the temperature of the heat medium flowing out of the first unit at predetermined intervals; a process of storing a plurality of temperature data detected or estimated in the most recent predetermined period as a data group consisting of a predetermined number of data; and a process of estimating the temperature of the heat medium flowing into the second unit by determining the maximum value from the data group.

Description

TECHNICAL FIELD

[0001] The technology disclosed in this specification relates to a control device of a cooling system. BACKGROUND

[0002] A control device of a cooling system is described in Japanese Patent Application Publication No. 2019-031200. The cooling system has a cooling path through which a heat medium flows in the order of a first unit, a second unit, and a radiator. The control device performs a process of detecting the temperature of the heat medium flowing into the first unit using a temperature sensor, a process of calculating the amount of heat dissipation of the heat medium in the radiator, and a process of estimating the temperature of the heat medium flowing into the radiator based on the detection value of the temperature sensor, the calculated amount of heat dissipation, and the like.

[0003] In the above-described cooling system, the heat medium flowing through the cooling path flows into the second unit after passing through the first unit. Therefore, in the case of monitoring the temperature of the heat medium flowing into the second unit, it is not necessary to provide a temperature sensor at the second unit, and the temperature of the heat medium flowing out of the first unit can be regarded as the temperature of the heat medium flowing into the second unit. However, there is a delay time corresponding to the distance from the first unit to the second unit and the flow rate of the heat medium during the period from when the heat medium flows out of the first unit to when it flows into the second unit. Therefore, the temperature of the heat medium flowing out of the first unit cannot be directly regarded as the temperature of the heat medium flowing into the second unit. That is, even if the detected or estimated temperature of the heat medium flowing out of the first unit is relatively low, a heat medium at a high temperature will actually flow into the second unit at that time. SUMMARY

[0004] The present disclosure provides a control device of a cooling system that can monitor the temperature of a heat medium flowing into a second unit based on the temperature of a heat medium flowing out of a first unit in a cooling system in which the heat medium flows in the order of the first unit and the second unit.

[0005] One aspect of the present disclosure provides a control device of a cooling system that has a cooling path through which a heat medium flows in the order of a first unit and a second unit, and cools the first unit and the second unit. The control device is configured to perform a process of repeatedly detecting or estimating the temperature of the heat medium flowing out of the first unit at predetermined intervals, a process of storing a plurality of temperature data detected or estimated in the most recent predetermined period as a data group composed of a predetermined number of data, and a process of estimating the temperature of the heat medium flowing into the second unit by determining the maximum value from the data group.

[0006] In the above structure, first, the temperature of the heat medium flowing out from the first unit is repeatedly detected or estimated at predetermined intervals. Then, a plurality of temperature data detected or estimated in the recent predetermined period is stored as a data group. The temperature of the heat medium flowing into the second unit is estimated based on a maximum value determined from the data group. That is, the maximum value of the temperature of the heat medium flowing out from the first unit in the recent predetermined period is determined, and the temperature of the heat medium flowing into the second unit is estimated based on the maximum value. According to such a structure, the temperature of the heat medium flowing into the second unit can be estimated from the temperature of the heat medium flowing out from the first unit, taking into account the delay time from when the heat medium flows out from the first unit to when it flows into the second unit. In addition, it is possible to avoid or suppress the actual temperature of the heat medium flowing into the second unit from exceeding the temperature estimated based on the temperature of the heat medium flowing out from the first unit. BRIEF DESCRIPTION OF DRAWINGS

[0007] Features, advantages, and technical and industrial significance of exemplary embodiments of the present application will be described below with reference to the accompanying drawings, wherein the same reference numerals denote the same elements throughout the figures, and wherein:

[0008] Figure 1 is a view showing the main structure of a vehicle 100 equipped with the cooling system 10 of the embodiment.

[0009] Figure 2 is a view for explaining the structure of the cooling system 10 of the embodiment. In addition, the first PCU 112, the second PCU 114, and the control device 116 of the vehicle 100 are also shown. T1 denotes the temperature of the heat medium flowing into the first PCU 112. T2 denotes the temperature of the heat medium flowing out from the first PCU 112. T3 denotes the temperature of the heat medium flowing into the second PCU 114.

[0010] Figure 3 Chart A of FIG. 1 shows the change in the torque target value TT of the first PCU 112 with time. Figure 3 Chart B of FIG. 1 shows the change in the temperature T2 of the heat medium flowing out from the first PCU 112 with time with respect to the change in the torque target value TT with time. Figure 3 Chart C of FIG. 1 likewise shows the change in the temperature T3 of the heat medium flowing into the second PCU 114 with time with respect to the change in the torque target value TT with time. In addition, the delay time DT is also shown.

[0011] Figure 4 is a flowchart showing an example of the temperature estimation processing performed by the cooling control device 20 of the embodiment 1.

[0012] Figure 5 Chart A of FIG. 1 shows the change in the torque target value TT of the first PCU 112 with time. Figure 5FIG. 3B shows a change in the temperature T2 of the heat medium flowing out from the first PCU 112 with respect to a change in the torque target value TT with time. Figure 5 FIG. 3C likewise shows a change in the estimated value T3' of the temperature T3 of the heat medium flowing into the second PCU 114 with respect to a change in the torque target value TT with time. Further, the predetermined period PT is also shown.

[0013] Figure 6 FIG. 4 is a graph showing an example of the relationship between the flow rate of the heat medium and the delay time DT.

[0014] Figure 7 FIG. 5 is a flowchart showing an example of the temperature estimation processing performed by the cooling control device 20 of Embodiment 2.

[0015] Figure 8 FIG. 3A shows the torque target value TT of the first PCU 112. Figure 8 FIG. 3B shows a change in the temperature T2 of the heat medium flowing out from the first PCU 112 with respect to a change in the torque target value TT with time. Figure 8 FIG. 3C likewise shows a change in the estimated value T3' of the temperature T3 of the heat medium flowing into the second PCU 114 with respect to a change in the torque target value TT with time. Further, the predetermined period PT is also shown.

[0016] Figure 9 FIG. 5 is a flowchart showing an example of the temperature estimation processing performed by the cooling control device 20 of Embodiment 3.

[0017] Figure 10 FIG. 3A shows the torque target value TT of the first PCU 112. Figure 10 FIG. 3B shows a change in the temperature T2 of the heat medium flowing out from the first PCU 112 with respect to a change in the torque target value TT with time. Figure 10 FIG. 3C likewise shows a change in the temperature T3 of the heat medium flowing into the second PCU 114 with respect to a change in the torque target value TT with time. Further, Figure 10 the curve F2 in FIG. 3B and Figure 10 the curve G1 in FIG. 3C correspond to a flow rate of the heat medium of 2 L / min. Figure 10 the curve F2 in FIG. 3B and Figure 10 the curve G2 in FIG. 3C correspond to a flow rate of the heat medium of 4 L / min. The delay times DT1, DT2 corresponding to each flow rate are also shown.

[0018] Figure 11 FIG. 6 is a graph showing an example of the relationship between the flow rate of the heat medium and the predetermined number of data constituting the data group.

[0019] Figure 12Fig. A of the drawing shows a change in the torque target value TT of the first PCU 112 with respect to time. Figure 12 Fig. B of the drawing shows a change in the temperature T2 of the heat medium flowing out from the first PCU 112 with respect to the change in the torque target value TT with respect to time. Figure 12 Fig. C of the drawing likewise shows a change in the estimated value T3' of the temperature T3 of the heat medium flowing into the second PCU 114 with respect to the change in the torque target value TT with respect to time. Further, Figure 12 The curve J1 in Fig. B of the drawing and Figure 12 The curve K1 in Fig. C of the drawing corresponds to a flow rate of the heat medium of 2 L / min. Figure 12 The curve J2 in Fig. B of the drawing and Figure 10 The curve K2 in Fig. C of the drawing corresponds to a flow rate of the heat medium of 4 L / min. Also shown are the predetermined periods PT1, PT2 corresponding to each flow rate.

[0020] Figure 13 Fig. 6 is a flowchart showing an example of the temperature estimation processing executed by the cooling control device 20 of Embodiment 4. DETAILED DESCRIPTION

[0021] In the above-described configuration, the control device can be configured to delete the oldest temperature data from the data group and store the latest temperature data in the storing processing when the number of the plurality of temperature data included in the data group reaches a predetermined data number. According to such a configuration, since the temperature data included in the data group is sequentially updated, the memory capacity required for the control device can be reduced.

[0022] In the above-described configuration, the control device can be configured to determine a maximum value every predetermined unit time with respect to the temperature repeatedly detected or estimated at predetermined intervals and store the maximum value as the temperature data constituting the data group in the storing processing. According to such a configuration, only one temperature data is stored every unit time, and it is not necessary to store all the temperature data for the recent predetermined period. Thus, the memory capacity required for the control device can be reduced.

[0023] In the above-described configuration, the control device can be configured to change the predetermined unit time in accordance with the flow rate of the heat medium. According to such a configuration, when the flow rate of the heat medium is relatively large, the estimation accuracy of the temperature of the heat medium flowing into the second unit can be improved by shortening the unit time. On the other hand, when the flow rate of the heat medium is relatively small, the number of the temperature data stored as the data group can be reduced by lengthening the unit time, and the memory capacity required for the control device can be reduced.

[0024] In the above-described configuration, the control device can be configured to change the predetermined number of data constituting a data group according to the flow rate of the heat medium. According to this configuration, for example, when the flow rate of the heat medium is large, the delay time from the outflow from the first unit to the inflow into the second unit is shortened, and thus it is possible to reduce the predetermined number of data constituting a data group. Thus, it is possible to reduce the memory capacity required for the control device.

[0025] A cooling system 10 of an embodiment and a vehicle 100 equipped with the cooling system 10 will be described with reference to the drawings. The vehicle 100 described herein is a so-called automobile, and is a vehicle that travels on a road surface. As shown in FIG. 1, the vehicle 100 is provided with a vehicle body 102 and a plurality of wheels 104f, 104r. The plurality of wheels 104f, 104r are rotatably attached to the vehicle body 102. Among the plurality of wheels 104f, 104r, a pair of front wheels 104f located at a front portion of the vehicle body 102 and a pair of rear wheels 104r located at a rear portion of the vehicle body 102 are included. The pair of front wheels 104f are coaxially arranged with each other, and the pair of rear wheels 104r are also coaxially arranged with each other. Note that the number of wheels 104f, 104r is not limited to four. In addition, although not particularly limited, the vehicle body 102 is made of a metal such as steel or aluminum alloy. Figure 1

[0026] As shown in FIG. 1, the vehicle 100 is also provided with a front-mounted motor 106 and a rear-mounted motor 108. The front-mounted motor 106 is connected to the pair of front wheels 104f and is capable of driving the pair of front wheels 104f. The rear-mounted motor 108 is connected to the pair of rear wheels 104r and is capable of driving the pair of rear wheels 104r. That is, the vehicle 100 is capable of four-wheel drive. Although not particularly limited, the front-mounted motor 106 and the rear-mounted motor 108 in the present embodiment are each a three-phase motor generator having a U-phase, a V-phase, and a W-phase. Figure 1

[0027] As shown in FIG. 1, the vehicle 100 is also provided with a battery 110. The battery 110 is built-in with a plurality of secondary battery cells and is configured to be repeatedly charged with external power. In addition, although not particularly limited, the battery 110 is a lithium-ion battery, a nickel-hydrogen battery, or the like. Figure 1

[0028] As shown in FIG. 1, the vehicle 100 is also provided with a battery 110. The battery 110 is built-in with a plurality of secondary battery cells and is configured to be repeatedly charged with external power. In addition, although not particularly limited, the battery 110 is a lithium-ion battery, a nickel-hydrogen battery, or the like. Figure 1 ​​​As shown, the vehicle 100 is also provided with two power conversion devices (Power Control Units, hereinafter referred to as "PCUs") 112, 114. The two PCUs 112, 114 are capable of controlling the supply of electric power to the corresponding electric motors 106, 108. The two PCUs 112, 114 include a first PCU 112 (first unit) and a second PCU 114 (second unit). The first PCU 112 is disposed between the battery 110 and the front-mounted electric motor 106. The first PCU 112 is capable of converting direct-current electric power from the battery 110 into alternating-current electric power and supplying it to the front-mounted electric motor 106. In addition, the first PCU 112 is capable of converting alternating-current electric power generated by the front-mounted electric motor 106 into direct-current electric power and supplying it to the battery 110. That is, the vehicle 100 is capable of charging the battery 110 by supplying regenerative electric power generated by the front-mounted electric motor 106 to the battery 110 at the time of braking. Although an example, the first PCU 112 is an inverter. In this case, the first PCU 112 can also have a DC-DC converter.

[0029] The second PCU 114 is disposed between the battery 110 and the rear-mounted electric motor 108. The second PCU 114 is capable of converting direct-current electric power from the battery 110 into alternating-current electric power and supplying it to the rear-mounted electric motor 108. In addition, the second PCU 114 is capable of converting alternating-current electric power generated by the rear-mounted electric motor 108 into direct-current electric power and supplying it to the battery 110. That is, the vehicle 100 is capable of charging the battery 110 by supplying regenerative electric power generated by the rear-mounted electric motor 108 to the battery 110 at the time of braking. Although an example, the second PCU 114 is an inverter. In this case, the second PCU 114 can also have a DC-DC converter.

[0030] As Figure 1As shown, the vehicle 100 is also provided with a control device 116. The control device 116 is a computer device having a processor, a memory, and the like. The control device 116 can be constituted by a single computer device, or can be constituted by a combination of a plurality of computer devices. The control device 116 is communicably connected to the front motor 106, the rear motor 108, the battery 110, the first PCU 112, and the second PCU 114, and can monitor and control the operations thereof. For example, operation information describing a user's operation, vehicle information showing a state of the vehicle 100 are input to the control device 116. The control device 116 controls the operations of the respective parts of the vehicle 100 in accordance with the input operation information and vehicle information. For example, the control device 116 can determine torque target values with respect to the front motor 106 and the rear motor 108 in accordance with the input operation information and vehicle information. Further, the control device 116 can perform feedback control of the operations of the first PCU 112 and the second PCU 114 so that actual torques output from the motors 106 and 108 are equal to the torque target values.

[0031] Next, the cooling system 10 of the embodiment will be described. The cooling system 10 of the embodiment cools the first PCU 112 and the second PCU 114. As shown in FIG. 1, the cooling system 10 is provided with a cooling path 12, a radiator 14, and a pump 16. Figure 2 The cooling path 12 is a path through which a heat medium flows. The heat medium can be, for example, cooling water. The radiator 14 performs heat exchange between the heat medium and outside air, and can release heat from the heat medium. The pump 16 is provided in the cooling path 12, and can adjust the flow rate of the heat medium flowing in the cooling path 12. The cooling path 12 is connected to the radiator 14, the first PCU 112, and the second PCU 114. By causing the heat medium to flow in the order of the first PCU 112 and the second PCU 114, heat is recovered from the first PCU 112 and the second PCU 114, respectively. Therefore, the temperature of the heat medium increases each time it passes through each of the first PCU 112 and the second PCU 114. Further, the temperature of the heat medium is decreased by releasing heat from the heat medium by the radiator 14.

[0032] As shown in FIG. 1, the cooling system 10 is provided with a cooling path 12, a radiator 14, and a pump 16. Figure 2As shown, the cooling system 10 also includes a temperature sensor 18. The temperature sensor 18 detects the temperature T1 of the heat medium flowing into the first PCU 112. Although this is just one example, the temperature sensor 18 is located within the first PCU 112. Furthermore, as in other embodiments, the temperature sensor 18 may also be located at a temperature that is substantially equal to the temperature T1 of the heat medium flowing into the first PCU 112. For example, as in this embodiment, when the temperature of the heat medium is considered to remain unchanged from the moment it passes through the heat sink 14 until it flows into the first PCU 112, the temperature sensor 18 may also be located at any point between the heat sink 14 and the first PCU 112.

[0033] like Figure 2 As shown, the cooling system 10 also includes a cooling control device 20. The cooling control device 20 is a computer device with a processor, memory, etc., that controls and monitors the operation of the cooling system 10. The cooling control device 20 can be a single computer device or a combination of multiple computer devices. The cooling control device 20 is communicatively connected to the temperature sensor 18 and can obtain the temperature detected by the temperature sensor 18. As described above, the detected temperature of the temperature sensor 18 indicates the temperature T1 of the heat medium flowing into the first PCU 112. The cooling control device 20 can adjust the flow rate of the heat medium, for example, by controlling the operation of the pump 16 based on the detected temperature of the temperature sensor 18. Alternatively, when the detected temperature of the temperature sensor 18 exceeds an allowable range, the cooling control device 20 sends a predetermined abnormal signal to the control device 116. Upon receiving this abnormal signal from the cooling control device 20, the control device 116 can prevent the first PCU 112 from overheating, for example, by limiting the operation of the first PCU 112.

[0034] In addition, the cooling control device 20 can estimate the temperature T2 of the heat medium flowing out of the first PCU112 by adding the temperature rise of the heat medium in the first PCU112 to the detected temperature of the temperature sensor 18. The heat medium flowing out of the first PCU112 then flows into the second PCU114. Therefore, by estimating the temperature T2 of the heat medium flowing out of the first PCU112, the temperature T3 of the heat medium flowing into the second PCU114 can be monitored without installing a temperature sensor in the second PCU114. Thus, similarly to the first PCU112, the cooling control device 20 can control the operation of the pump 16 based on the temperature T3 of the heat medium flowing into the second PCU114, or limit the operation of the second PCU114 by the control device 116. Here, the temperature rise of the heat medium in the first PCU112 can be appropriately calculated based on indicators related to the heat generation of the first PCU112, such as the torque target value TT of the first PCU112, and indicators related to the cooling of the first PCU112, such as the temperature and flow rate of the heat medium. In addition, as another implementation, instead of estimating the temperature of the heat medium flowing out of the first PCU112, the cooling system 10 may also include a temperature sensor that directly measures the temperature.

[0035] However, during the period from when the heat medium flows out of the first PCU112 to when it flows into the second PCU114, there exists a delay time DT corresponding to the distance from the first PCU112 to the second PCU114 and the flow rate of the heat medium. For example, as Figure 3 As shown in Figure A, the target torque value TT of the first PCU112 is set to its maximum value from time t0 to time t1. In this case, the first PCU112 generates significant heat from time t0 to time t1. The result is as follows: Figure 3 As shown in Figure B, the temperature T2 of the heat medium flowing out of the first PCU112 temporarily rises from the timing point t0. In contrast, as... Figure 3 As shown in Figure C, the temperature T3 of the heat medium flowing into the second PCU114 will temporarily rise after a delay of the aforementioned delay time DT, starting from the timing of t2. Therefore, the temperature T2 of the heat medium flowing out of the first PCU112 cannot be directly regarded as the temperature T3 of the heat medium flowing into the second PCU114.

[0036] Regarding the above situation, the cooling control device 20 is configured to execute... Figure 4 The temperature estimation process shown here estimates the temperature T3 of the heat medium flowing into the second PCU114 based on the temperature T2 of the heat medium flowing out of the first PCU112. Hereinafter, according to... Figure 4 The flowchart shown illustrates the temperature estimation process performed by the cooling control device 20.

[0037] In step S10, the cooling control device 20 repeatedly estimates the temperature T2 of the heat medium flowing out of the first PCU112 at predetermined intervals. As described above, the cooling control device 20 can estimate the temperature T2 of the heat medium flowing out of the first PCU112 based on the temperature detected by the temperature sensor 18. However, in other embodiments, instead of estimating the temperature T2 of the heat medium flowing out of the first PCU112, the temperature T2 of the heat medium flowing out of the first PCU112 can be directly measured. Furthermore, the predetermined interval is, for example, 0.1 seconds. In addition, the predetermined interval can be appropriately changed according to the object being cooled, etc.

[0038] The cooling control device 20 executes the processing after step S12 repeatedly in parallel with step S10. In step S12, the cooling control device 20 will [perform the process] within the nearest predetermined period PT (refer to [the specified time]). Figure 5 Multiple estimated temperature data points are stored as a data set consisting of a predetermined number of data points. The predetermined period PT mentioned here is set based on the aforementioned delay time DT. Furthermore, the delay time DT from the flow out of the first PCU112 to the flow into the second PCU114 varies according to the flow rate of the heat medium, reaching its maximum value when the flow rate of the heat medium is set to a lower limit. Although this is just one example, in the cooling system 10 of this embodiment, as... Figure 6 As shown, the configuration allows for adjusting the flow rate of the heat transfer medium within a range of 2 L / min to 10 L / min. When the flow rate of the heat transfer medium is set to 2 L / min, the delay time DT is 30 seconds. Therefore, in this embodiment, the predetermined period PT for storing multiple temperature data is set to the maximum value of the delay time DT, i.e., 30 seconds. However, as in other embodiments, the predetermined period PT is not limited to the maximum value of the delay time DT and may be set to a value larger than that maximum value.

[0039] The predetermined amount of data stored in the cooling control device 20 is determined based on the predetermined interval and predetermined period PT. For example, if the predetermined period PT is 30 seconds, then the estimated temperature data of the heat medium every 0.1 seconds in step S10 is stored up to 300. That is, a data group consisting of 300 temperature data points is formed in the cooling control device 20. Furthermore, when the number of temperature data points contained in the data group reaches the predetermined number of data points (300 in this case), the oldest temperature data is deleted from the data group, and the latest temperature data is re-stored. Thus, at any given time, only the temperature data that has been traced back to the predetermined period PT (30 seconds in this case) from that time is stored in the cooling control device 20. According to this structure, since the temperature data contained in the data group is updated sequentially, the memory capacity required by the cooling control device 20 can be reduced.

[0040] In step S14, the cooling control device 20 determines the temperature data that takes the maximum value from among the data sets stored in step S12. The temperature data determined here is the maximum value of the temperature data estimated in step S10 during the latest predetermined period PT, and is the maximum value of the temperature T2 of the heat medium flowing out from the first PCU 112. As described above, the predetermined period PT is based on the maximum value of the delay time DT of the period from when the heat medium flows out from the first PCU 112 to when it flows into the second PCU 114. Therefore, the heat medium flowing out from the first PCU 112 is most likely to flow into the second PCU 114 with a delay of the predetermined period PT. Therefore, the maximum value of the temperature data determined in this step S14 can be regarded as the maximum value that can be taken by the temperature T3 of the heat medium flowing into the second PCU 114 at that time.

[0041] In step S16, the cooling control device 20 estimates the temperature T3 of the heat medium flowing into the second PCU 114 based on the maximum value determined in step S14. In the present embodiment, the maximum value determined in step S14 is regarded as the estimated value T3' of the temperature T3 of the heat medium flowing into the second PCU 114. However, in other embodiments, the cooling control device 20 can also determine the estimated value T3' of the temperature T3 of the heat medium flowing into the second PCU 114 from the maximum value determined in step S14 using a predetermined relationship or the like.

[0042] By the above processing, the cooling control device 20 can estimate the temperature T3 of the heat medium flowing into the second PCU 114 from the temperature T2 of the heat medium flowing out from the first PCU 112, taking into account the delay time DT of the period from when the heat medium flows out from the first PCU 112 to when it flows into the second PCU 114. For example, as shown in chart A of FIG. 10, from time t0 to time t1, the torque target value TT of the first PCU 112 is set to the maximum value. In this case, as shown in chart B of FIG. 10, the temperature T2 of the heat medium flowing out from the first PCU 112 temporarily rises from the timing of time t0, and becomes the maximum value at time t1. In contrast, in the cooling control device 20, the maximum value of the temperature T2 of the heat medium flowing out from the first PCU 112 is determined for the latest predetermined period PT. Then, the temperature T3 of the heat medium flowing into the second PCU 114 is estimated based on this maximum value. Therefore, as shown in chart C of FIG. 10, the estimated value T3' of this temperature T3 rises from time t0 to time t1, and is maintained at the maximum value of the temperature T2 at time t1 (or a value based on this maximum value) during the period from time t1 to time t3, which is delayed by the predetermined period PT. As a result, it is possible to avoid the temperature T3 of the heat medium actually flowing into the second PCU 114 from exceeding the estimated value T3' based on the cooling control device 20. Figure 5 Figure 5 Figure 5 ​​​

[0043] In addition, in the cooling control device 20 of this embodiment, during the processing in step S14, when the number of multiple temperature data contained in the data group reaches a predetermined number of data, the oldest temperature data is deleted from the data group, and the latest temperature data is stored. Based on this structure, since the temperature data contained in the data group is updated sequentially, the memory capacity required by the cooling control device 20 can be reduced.

[0044] (Example 2)

[0045] Reference Figure 7 , 8 The cooling system of Example 2 will be described below. Compared to the cooling system 10 of Example 1, the cooling system of this example differs in that the temperature estimation process performed by the cooling control device 20 is modified. Specifically, the cooling control device 20 of this example is configured to perform… Figure 7 The temperature estimation process is shown. In this temperature estimation process, the following will be performed: Figure 4 The temperature estimation process step S12 of Example 1 shown is modified into steps S12A and S12B. In the description of this embodiment, the same reference numerals are used for structures shared with Example 1, thus, repeated descriptions are omitted.

[0046] exist Figure 7 In the temperature estimation process shown, the cooling control device 20 repeatedly executes the processes after step S12A in parallel with the process of step S10. In step S12A, the cooling control device 20 determines a maximum value every predetermined unit time for the temperature repeatedly estimated at predetermined intervals. The predetermined unit time mentioned here is, for example, 3 seconds. That is, for the temperature T2 of the heat medium repeatedly estimated (or detected) every 0.1 seconds in step S10, the maximum value is determined every 3 seconds in step S12A. Here, the predetermined unit time for determining the maximum value is not limited to a specific time, but can be set to a time shorter than the minimum value of the delay time DT. In the case of this embodiment, as... Figure 6 As shown, the minimum delay time DT is 6 seconds. Therefore, the time required for a series of temperature estimation processes is also considered as a predetermined unit of time and set to 3 seconds, which is significantly shorter than 6 seconds.

[0047] Next, in step S12B, the cooling control device 20 stores the plurality of maximum values determined in step S12A for the latest predetermined period PT as a data group composed of a predetermined number of data. As in Embodiment 1, the predetermined period PT is set to match the maximum value of the delay time DT from the time when the heat medium flows out of the first PCU 112 to the time when it flows into the second PCU 114. For example, in the case where the predetermined period PT is 30 seconds and the predetermined unit time is 3 seconds, in the cooling control device 20, the temperature data of the maximum values determined in step S12A are stored for 10. At this point, in the cooling control device 20 of the present embodiment, the memory capacity required for storing the data group can be reduced.

[0048] The process after step S14 of Embodiment 2 is the same as that after step S14 of Embodiment 1. However, as described above, in the cooling control device 20 of the present embodiment, the maximum value determined every predetermined unit time is stored. Therefore, the maximum value determined in step S14 of the present embodiment changes in stages compared to the maximum value determined in step S14 of Embodiment 1.

[0049] By the above process, in the cooling control device 20 of the present embodiment, too, the temperature T3 of the heat medium flowing into the second PCU 114 can be estimated from the temperature T2 of the heat medium flowing out of the first PCU 112, taking into account the delay time DT of the period from the time when the heat medium flows out of the first PCU 112 to the time when it flows into the second PCU 114. For example, as shown in chart A of FIG. 10, from time to to time tl, the torque target value TT of the first PCU 112 is set to the maximum value. In this case, as shown in chart B of FIG. 10, the temperature T2 of the heat medium flowing out of the first PCU 112 temporarily rises from the timing of time to and becomes the maximum value at time tl. In contrast, in the cooling control device 20, the maximum values (TM1, TM2,...) of the temperature T2 of the heat medium flowing out of the first PCU 112 are determined every predetermined unit time (for example, 3 seconds). Then, the maximum value for the latest predetermined period PT is determined from among the maximum values (TM1, TM2,...) determined every predetermined unit time. Then, the temperature T3 of the heat medium flowing into the second PCU 114 is estimated based on this maximum value. Therefore, as shown in chart C of FIG. 10, the temperature T3 of the heat medium flowing into the second PCU 114 is estimated to be lower than the temperature T2 of the heat medium flowing out of the first PCU 112. Figure 8 Figure 8 Figure 8 ​​The estimated value T3' of the temperature T3 is phasedly raised from the time t0 to the time tl as shown in the graph C. Among the maximum values (TM1, TM2,...) determined every predetermined unit time, the maximum value (or a value based on the maximum value) of the temperature T2 at the time of the maximum value (TM3) is maintained during a period from the time of attaining the maximum value (TM3) to the time delayed by the predetermined period PT. As a result, it is possible to avoid or suppress the temperature T3 of the heat medium actually flowing into the second PCU 114 from exceeding the estimated value T3' based on the cooling control device 20.

[0050] In addition to this, in the cooling control device 20 of Embodiment 2, the maximum value is determined every predetermined unit time with respect to the temperature repeatedly detected or estimated at predetermined intervals in step S10 (step S12A), and the maximum value is stored as temperature data constituting a data group (step S12B). According to such a structure, only one temperature data is stored every unit time during the recent predetermined period PT, and it is not necessary to store all the temperature data during the recent predetermined period PT. Thus, it is possible to reduce the memory capacity required for the cooling control device 20.

[0051] In the above-described embodiments, the cooling control device 20 can also change the predetermined unit time for determining the maximum value in accordance with the flow rate of the heat medium. According to such a structure, when the flow rate of the heat medium is relatively large, it is possible to improve the estimation accuracy of the temperature T3 of the heat medium flowing into the second PCU 114 by shortening the unit time. On the other hand, when the flow rate of the heat medium is relatively small, it is possible to reduce the number of temperature data stored as a data group by lengthening the unit time, and it is possible to reduce the memory capacity required for the cooling control device 20.

[0052] (Embodiment 3)

[0053] Reference Figures 9-12 A cooling system of Embodiment 3 will be described. The cooling system of this embodiment is different from the cooling systems of Embodiments 1 and 2 in that the temperature estimation processing performed by the cooling control device 20 is changed. Specifically, the cooling control device 20 of this embodiment is configured to perform the temperature estimation processing shown in FIG. 9. In this temperature estimation processing, the temperature of the heat medium flowing into the second PCU 114 is estimated based on the temperature of the heat medium flowing into the first PCU 112. Figure 9 Figure 4 The processing of steps S6 and S8 is added before the processing of step S10 in the temperature estimation processing of Embodiment 1 shown in FIG. 6. In the description of this embodiment, the same reference numerals are attached to the structures common to Embodiment 1, and thus the repeated description is omitted.

[0054] ​In step S6, the cooling control device 20 obtains the flow rate of the heat medium. As described above, in this embodiment, the pump 16 is configured to adjust the flow rate of the heat medium according to the operation command sent from the cooling control device 20. Therefore, the cooling control device 20 can determine the flow rate of the heat medium based on a self-set operation command value for the pump 16. However, as another embodiment, the cooling control device 20 may also use a sensor or the like to obtain the actual flow rate of the heat medium.

[0055] In step S8, the cooling control device 20 sets a predetermined amount of data to be stored as a data set based on the flow rate of the heat medium obtained in step S6. As described above, the delay time DT from the exit of the first PCU112 to the flow into the second PCU114 changes with the change in the flow rate of the heat medium (refer to...). Figure 6 For example, such as Figure 10 As shown in Figure A, from time t0 to time t1, the target torque value TT of the first PCU112 is set to its maximum value. In this case, as... Figure 10 As shown in Figure B, the temperature T2 of the heat medium flowing out of the first PCU112 temporarily rises from the timing point t0. At this time, the smaller the flow rate of the heat medium, the more heat the heat medium can recover from the first PCU112. Therefore, the smaller the flow rate of the heat medium, the larger the maximum temperature of the heat medium (i.e., curve F1 > curve F2). In this case, as... Figure 10 As shown in Figure C, the temperature T3 of the heat medium flowing into the second PCU114 temporarily increases due to delays DT1 and DT2 corresponding to the flow rate of the heat medium. Figure 6 As shown, for example, when the flow rate of the heat medium is 2L / min, the delay time DT1 is 30 seconds, and when the flow rate of the heat medium is 4L / min, the delay time DT2 is 15 seconds.

[0056] Based on the above, in step S8, the predetermined number of data stored by the cooling control device 20 in step S12 is set to the number of temperature data estimated in step S10 within the most recent predetermined periods PT1 and PT2. The predetermined periods PT1 and PT2 are set based on delay times DT1 and DT2 corresponding to the flow rate of the heat medium. For example, when the flow rate of the heat medium is 2 L / min, the predetermined period PT1 is set to the delay time DT1 (i.e., 30 seconds) corresponding to the flow rate of the heat medium. Since the number of temperature data points of the heat medium estimated every 0.1 seconds in step S10 is 300, the predetermined number of data points stored as a data set in step S8 is set to 300 (see reference). Figure 11). Likewise, when the flow rate of the heat medium is 4 L / min, the predetermined period PT2 is set to the corresponding delay time DT2 (i.e., 15 seconds), and the predetermined number of data stored as the data group is set to 150 in step S8 (refer to Figure 11 At this point, in the cooling control device 20 of the present embodiment, it is possible to reduce the memory capacity required to store the data group composed of the predetermined number of data.

[0057] The process after step S10 of Embodiment 3 is the same as that after step S10 of Embodiment 1.

[0058] By the above process, in the cooling control device 20 of the present embodiment, it is also possible to take into account the delay times DT1, DT2 of the period from the outflow of the heat medium from the first PCU 112 to the inflow of the heat medium into the second PCU 114, and to estimate the temperature T3 of the heat medium flowing into the second PCU 114 from the temperature T2 of the heat medium flowing out of the first PCU 112. For example, as shown in chart A of Figure 12 from time t0 to time tl, the torque target value TT of the first PCU 112 is set to the maximum value. In this case, as shown in chart B of Figure 12 from time t0 to time tl, the torque target value TT of the first PCU 112 is set to the maximum value. In this case, as shown in chart B of Figure 12 from time t0 to time tl, the torque target value TT of the first PCU 112 is set to the maximum value. In this case, as shown in chart B of

[0059] In addition to this, the cooling control device 20 of Embodiment 3 is able to change the predetermined number of data stored as the data group in accordance with the flow rate of the heat medium. According to such a structure, for example, when the flow rate of the heat medium is relatively large, the delay times DT1, DT2 of the period from the outflow of the heat medium from the first PCU 112 to the inflow of the heat medium into the second PCU 114 become shorter, and thus it is possible to reduce the predetermined number of data constituting the data group. Thereby, it is possible to reduce the memory capacity required for the cooling control device 20.

[0060] (Embodiment 4)

[0061] Refer to Figure 13The cooling system of Example 4 will be described. In the cooling system of this example, the temperature estimation processing performed by the cooling control device 20 is changed compared to the cooling systems of Examples 1 to 3. Specifically, the cooling control device 20 of this example is configured to perform the temperature estimation processing shown in FIG. 8. In this temperature estimation processing, the processing of steps S6 and S8 described in Example 3 is added to the temperature estimation processing of Example 2. Figure 13 Figure 7 The cooling control device 20 of this example is equivalent to the cooling control device 20 of Example 2 changed in a manner that the predetermined number of data stored as data groups is changed in accordance with the flow rate of the heat medium.

[0062] As is clear from the description thus far, in the cooling control device 20 of this example, the temperature T3 of the heat medium flowing into the second PCU 114 can also be estimated in accordance with the temperature T2 of the heat medium flowing out of the first PCU 112, taking into account the delay time during the period from the outflow of the heat medium from the first PCU 112 to the inflow of the heat medium into the second PCU 114.

[0063] Furthermore, the two cooling targets of the cooling system 10 of Examples 1 to 4 are not necessarily the first PCU 112 and the second PCU 114. As other embodiments, the cooling system 10 can take either of the PCUs 112, 114 and another heat source (for example, an engine) as a cooling target. As still another embodiment, two other heat sources can be taken as cooling targets.

[0064] The above detailed some specific examples, but these are merely illustrative and do not limit the claims. The technology recited in the claims includes solutions obtained by various modifications and changes to the above-described specific examples. The technical elements described in the specification or the drawings can be used singly or in combination to exhibit technical usefulness.​

Claims

1. A control device of a cooling system that has a cooling path through which a heating medium flows in the order of a first unit and a second unit, and that cools the first unit and the second unit, characterized by comprising: a process of repeatedly detecting or estimating a temperature of the heating medium flowing out of the first unit at predetermined intervals; a process of storing a plurality of temperature data detected or estimated in a predetermined period as a data group composed of a predetermined number of data; and a process of estimating a temperature of the heating medium flowing into the second unit by determining a maximum value from the data group, wherein the predetermined period is set in accordance with a delay time from when the heating medium flows out of the first unit to when the heating medium flows into the second unit, and wherein the control device is further configured to change the predetermined number of data stored as the data group in accordance with a flow rate of the heating medium.

2. The control device of the cooling system according to claim 1, wherein the control device is configured to delete an oldest temperature data from the data group when a number of the plurality of temperature data included in the data group reaches the predetermined number of data in the process of storing, and to store a latest temperature data.

3. The control device of the cooling system according to claim 1 or 2, wherein the control device is configured to determine a maximum value every predetermined unit time for the temperature repeatedly detected or estimated at predetermined intervals in the process of storing, and to store the maximum value as a temperature data constituting the data group.

4. The control device of the cooling system according to claim 3, wherein the control device is configured to change the predetermined unit time in accordance with a flow rate of the heating medium. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

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