Grille shutter control device

Abstract

To provide a control device for a grille shutter capable of further reducing energy consumption of an entire vehicle.SOLUTION: An on-vehicle air conditioning system 10 includes a compressor 24 compressing a first refrigerant, a main radiator 54 located behind a grille opening 92, and a grille shutter 94 opening / closing the grille opening 92. A control device 90 of the grille shutter 94 opens / closes the grille shutter 94 based on a pressure P of the first refrigerant at an outlet of the compressor 24, an outside temperature T, and a vehicle speed V.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present specification discloses a control device for controlling the opening and closing of a grill shutter. [Background technology]

[0002] Typically, an in-vehicle air conditioning system has a main radiator, which exchanges heat between the refrigerant and outside air. A grille opening is formed in front of the main radiator. A large amount of outside air flows toward the main radiator through the grille opening, improving the heat exchange efficiency of the refrigerant and, ultimately, the air conditioning efficiency.

[0003] On the other hand, if the grille opening is open, aerodynamic resistance increases and the energy consumption required for running the vehicle increases. Therefore, some have proposed providing a grille shutter that opens and closes the grille opening.

[0004] For example, Patent Document 1 discloses a technology in which a grille shutter is provided on a vehicle and the grille shutter is closed when the vehicle speed is above a predetermined speed (for example, 60 km / h). By adopting such a configuration, the energy consumption required for running the vehicle can be reduced to some extent. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2021-133725 Summary of the Invention [Problem to be solved by the invention]

[0006] However, when the grille shutter is closed, the energy required for driving decreases, but the energy required for air conditioning may increase. In Patent Document 1, the grille shutter is closed according to the vehicle speed without considering the increase or decrease in the energy required for air conditioning. As a result, with the conventional technology such as Patent Document 1, there is a risk that the energy consumption of the entire vehicle may increase.

[0007] Therefore, this specification discloses a grille shutter control device that can further reduce the energy consumption of the entire vehicle. [Means for solving the problem]

[0008] The grill shutter control device disclosed in this specification is a control device that controls the opening and closing of a grill shutter incorporated in an automotive air conditioning system, the automotive air conditioning system comprising: a compressor that compresses a first refrigerant; a main radiator arranged behind a grill opening and that exchanges heat between the first refrigerant or a second refrigerant that exchanges heat with the first refrigerant and outside air; and the grill shutter that opens and closes the grill opening, the control device opening and closing the grill shutter based on a first parameter that represents the load of the compressor, a second parameter that represents the temperature of the ambient environment of the air conditioning system or the temperature of the object to be temperature-controlled, and vehicle speed, the first parameter being the pressure of the first refrigerant or the temperature of the first refrigerant at the outlet of the compressor, and the second parameter being the outside air temperature, or the indoor temperature, or the temperature of the evaporator during cooling operation, or the temperature of the heater core during heating operation.

[0009] With this configuration, by taking into consideration the vehicle speed, the first parameter, and the second parameter, it is possible to take into account not only the energy required for driving but also the energy required for air conditioning. By opening and closing the grille shutters based on these three parameters, it is possible to further reduce the energy consumption of the entire vehicle.

[0010] In this case, the control device may identify the vehicle speed value at which the grill shutter should be opened or closed as a switching vehicle speed threshold based on the value of the second parameter, close the grill shutter when the actual vehicle speed value exceeds the switching vehicle speed threshold, open the grill shutter when the actual vehicle speed value is equal to or less than the switching vehicle speed threshold, and further open the grill shutter regardless of the vehicle speed value when the value of the first parameter exceeds a predetermined standard load.

[0011] With this configuration, it is possible to prevent the compressor from being overloaded and reduce the energy consumption of the entire vehicle.

[0012] In addition, the control device may identify the value of the first parameter at which the grill shutter should be switched between open and closed based on the vehicle speed and the second parameter as a switching load threshold, and open and close the grill shutter depending on the comparison result between the actual value of the first parameter and the switching load threshold.

[0013] With this configuration, it is possible to more appropriately determine whether the grille shutter should be opened or closed, and it is possible to more reliably reduce the energy consumption of the entire vehicle.

[0014] In this case, the switching load threshold is the value of the first parameter when the aerodynamic energy increase amount and the air conditioning energy increase amount are balanced, the aerodynamic energy increase amount is the increase in energy consumption caused by the increase in aerodynamic resistance when the grill shutter is opened compared to when it is closed, and the air conditioning energy increase amount may be the increase in energy consumption caused by the increase in air conditioning load when the grill shutter is closed compared to when it is opened.

[0015] With this configuration, it is possible to more appropriately determine whether the grille shutter should be opened or closed, and it is possible to more reliably reduce the energy consumption of the entire vehicle.

[0016] The switching load threshold may also include an opening threshold and a closing threshold lower than the opening threshold, and the control device may open the grill shutter when the actual measured value of the first parameter crosses the opening threshold in an increasing direction, and close the grill shutter when the actual measured value of the first parameter crosses the closing threshold in a decreasing direction.

[0017] This configuration can prevent the grille shutter from being frequently switched between open and closed states within a short period of time.

[0018] The air conditioning system may further include a sub-radiator that is provided at a position that is not affected by opening and closing of the grill shutter and that exchanges heat between the first refrigerant or the second refrigerant and outside air.

[0019] By providing a sub-radiator, the efficiency of heat exchange between the outside air and the refrigerant can be maintained to a certain extent even when the grille shutter is closed, thereby reducing the energy consumption of the vehicle as a whole. [Effects of the Invention]

[0020] According to the technology disclosed in this specification, the energy consumption of the entire vehicle can be further reduced. [Brief explanation of the drawings]

[0021] [Figure 1] FIG. 2 is a diagram illustrating the configuration of an air conditioning system and a control device during cooling operation. [Figure 2] FIG. 2 is a diagram illustrating the configuration of an air conditioning system and a control device during heating operation. [Figure 3] 10 is a graph showing the relationship between energy consumption for air conditioning and vehicle speed. [Figure 4] 10 is a graph showing an increase in aerodynamic energy and an increase in air conditioning energy. [Figure 5] 4 is a flowchart showing a flow of opening and closing control of the grille shutter. [Figure 6] FIG. 10 is a diagram illustrating an example of a reference temperature. [Figure 7]10 is a graph showing an increase in aerodynamic energy and an increase in air conditioning energy. [Figure 8] FIG. 10 is a diagram illustrating an example of a switching first threshold value table. [Figure 9] 10 is a flowchart showing another example of the opening and closing control of the grille shutter. DETAILED DESCRIPTION OF THE INVENTION

[0022] The control device 90 for the grill shutter 94 will be described below with reference to the drawings. First, the air conditioning system 10 into which the grill shutter 94 is incorporated will be described. FIGS. 1 and 2 are diagrams showing the configurations of the air conditioning system 10 and the control device 90. In FIG. 1, the arrows superimposed on the refrigerant flow paths indicate the direction of refrigerant flow during cooling operation. In FIG. 2, the arrows superimposed on the refrigerant flow paths indicate the direction of refrigerant flow during heating operation.

[0023] 1 and 2 is mounted on a vehicle to adjust the temperature of the air inside the vehicle. While the configuration of the vehicle is not particularly limited, this example will be described taking as an example an air conditioning system 10 mounted on an electric vehicle that is driven by the power of a motor. The air conditioning system 10 has a first refrigerant circuit 20 through which a first refrigerant flows, a second refrigerant circuit 50 through which a second refrigerant flows, and a third refrigerant circuit 70 through which a third refrigerant flows.

[0024] The first refrigerant circuit 20 is a heat pump circuit that transfers heat by expanding and compressing a first refrigerant and exchanging heat between the first refrigerant and a second or third refrigerant. The first refrigerant circuit 20 has a main flow path 22a and a bypass flow path 22b. The main flow path 22a is an annular flow path. The main flow path 22a is provided with a compressor 24 that compresses the first refrigerant, a condenser 26 that exchanges heat between the compressed first refrigerant and the second refrigerant, a modulator 28 that separates the first refrigerant into gas and liquid after passing through the condenser 26, an expansion valve 34a that expands the first refrigerant after gas-liquid separation, and a chiller 32 that exchanges heat between the expanded first refrigerant and a third refrigerant.

[0025] The bypass flow path 22b is a flow path that connects a point upstream of the chiller 32 and a point downstream of the chiller 32. The bypass flow path 22b is provided with an expansion valve 34b that expands the first refrigerant and an evaporator 30 that vaporizes the expanded first refrigerant. A three-way valve 36 is disposed at the branch point between the main flow path 22a and the bypass flow path 22b. The pressure and temperature of the first refrigerant output from the compressor 24 are detected by a pressure sensor 38 and a temperature sensor 40 as a refrigerant pressure P and a refrigerant temperature.

[0026] The second refrigerant circuit 50 is a circuit that transfers heat using a second refrigerant. The second refrigerant circuit 50 has a circular main flow path 52a and a bypass flow path 52b that shortcuts the main flow path 52a. In addition to the condenser 26, the main flow path 52a further includes a heater 62 that heats the second refrigerant, a sub-radiator 56 and a main radiator 54 that exchange heat between the second refrigerant and outside air, and a pump 58 that pumps the second refrigerant. The bypass flow path 52b connects a point upstream of the pump 58 with a point downstream of the heater 62. A heater core 60 is provided in this bypass flow path 52b. A three-way valve 64 is provided at the branch point between the main flow path 52a and the bypass flow path 52b.

[0027] Here, the main radiator 54 is larger than the sub-radiator 56. The main radiator 54 is disposed behind the grill opening 92 so as to face the grill opening 92. The grill opening 92 is an opening formed in the front end surface of the vehicle, and is an opening through which wind passes as the vehicle travels. The grill opening 92 is provided with a grill shutter 94 that can open and close the grill opening 92. In addition, a temperature sensor 96 that detects an outside air temperature T is provided near the front end of the vehicle.

[0028] The third refrigerant circuit 70 is a circuit that transfers heat using a third refrigerant. The third refrigerant circuit 70 has an annular main flow path 72a, a bypass flow path 72b that shortcuts the main flow path 72a, and an outer flow path 72c. In addition to the chiller 32 described above, the main flow path 72a is provided with a pump 76 that pressure-feeds the third refrigerant to the chiller 32. The bypass flow path 52b is a flow path that connects a point upstream of the pump 76 with a point downstream of the chiller 32. A battery 82, which is one of the objects to be temperature-controlled, is arranged in the bypass flow path 52b.

[0029] The outer flow path 72c is a flow path for regulating the temperatures of electronic devices (for example, the power control unit 86 and the smart power unit 84) and a transaxle 88 (hereinafter abbreviated as "T / A 88"). The outer flow path 72c passes through the interior of the electronic devices, thereby cooling the electronic devices. The outer flow path 72c is also provided with an oil cooler 73 that exchanges heat between the third refrigerant and the lubricating oil of the T / A 88, and a low-temperature radiator 74 that exchanges heat between the third refrigerant and the outside air. The low-temperature radiator 74 is disposed behind the main radiator 54.

[0030] Outer flow path 72c flows from the branch point where main flow path 72a branches into bypass flow path 72b toward low-temperature radiator 74, passes through electronic equipment and oil cooler 73, and returns to the branch point again. A five-way valve 80 is disposed at this branch point.

[0031] The control device 90 controls the operation of the air conditioning system 10 and also controls the opening and closing of the grill shutter 94. The control device 90 is physically a computer having a processor 90a and a memory 90b. The control device 90 may be configured as a single computer, or may be configured as a combination of multiple computers that are mechanically separated from each other.

[0032] Next, a brief description will be given of the flow of operations when cooling the interior of a vehicle in the air conditioning system 10. During cooling operation, as shown in FIG. 1, the three-way valve 36 is switched so that the first refrigerant passes through the bypass flow path 22b but does not pass through the chiller 32. The three-way valve 64 is also switched so that the second refrigerant does not pass through the bypass flow path 52b. The first refrigerant is pressurized by the compressor 24, cooled and liquefied by the condenser 26, and then separated into gas and liquid by the modulator 28. The liquid first refrigerant rapidly expands and vaporizes as it passes through the expansion valve 34b and the evaporator 30. As the first refrigerant vaporizes, the air around the evaporator 30 is cooled. This cooled air is sent into the vehicle to cool the interior.

[0033] The second refrigerant that has exchanged heat with the first refrigerant in the condenser 26 becomes hotter than the outside air. This high-temperature second refrigerant is cooled by heat exchange with the outside air in the sub-radiator 56 and the main radiator 54. The cooled second refrigerant is supplied back to the condenser 26, where it cools and liquefies the first refrigerant.

[0034] At this time, heater 62 remains off. Also, in this case, the first refrigerant does not flow through chiller 32. Therefore, the third refrigerant that has exchanged heat with the electronic devices and T / A 88 reaches low-temperature radiator 74 while still in a high-temperature state without being cooled by chiller 32. At this time, because the third refrigerant is hotter than the outside air temperature T, it releases heat to the outside air and is cooled as it passes through low-temperature radiator 74.

[0035] Next, a brief description will be given of the flow when heating the vehicle interior. During heating operation, as shown in Fig. 2, the three-way valve 36 is switched so that the first refrigerant passes through the chiller 32 without passing through the bypass flow path 22b. In addition, the three-way valve 64 is switched so that the second refrigerant passes through the bypass flow path 52b without passing through the sub-radiator 56 and the main radiator 54.

[0036] The first refrigerant is pressurized by compressor 24, cooled and liquefied by condenser 26, and then separated into gas and liquid by modulator 28. The low-temperature liquid first refrigerant is reduced in pressure by passing through expansion valve 34a. The low-temperature, low-pressure first refrigerant exchanges heat with a third refrigerant and is heated while passing through chiller 32. The heated first refrigerant is supplied to compressor 24 again.

[0037] The second refrigerant is heated by heat exchange with the first refrigerant in the condenser 26. The second refrigerant output from the condenser 26 is further heated by the heater 62 and flows into the heater core 60. This causes the heater core 60, and in turn the air around the heater core 60, to become hot. This hot air is sent into the vehicle interior, thereby heating the interior of the vehicle.

[0038] The third refrigerant is cooled by exchanging heat with the first refrigerant in chiller 32. After cooling, the third refrigerant has a temperature lower than that of the outside air. Therefore, when this third refrigerant passes through low-temperature radiator 74, the third refrigerant absorbs heat from the outside air and is heated. The heated third refrigerant is sent back to chiller 32 and transfers heat to the first refrigerant.

[0039] As is clear from the above explanation, efficient heating and cooling and reducing the energy consumption (i.e., power consumption) required for air conditioning require efficient heat exchange between the refrigerant and the outside air temperature. Naturally, efficient heat exchange between the refrigerant and the outside air temperature can be achieved by opening grille shutter 94 and allowing a large amount of outside air to flow toward main radiator 54 and low-temperature radiator 74.

[0040] However, when the grill shutter 94 is opened, the aerodynamic resistance generated when the vehicle is traveling increases accordingly, and the energy consumption required for traveling the vehicle (electric power consumption in the case of an electric vehicle) increases compared to when the grill shutter 94 is closed. Hereinafter, the increase in the energy required for traveling the vehicle resulting from the opening of the grill shutter 94 will be referred to as the "aerodynamic energy increase Ead." This aerodynamic energy increase Ead increases as the vehicle speed V increases.

[0041] Therefore, depending on the vehicle speed V, the outside air temperature T, and the refrigerant pressure P, opening the grille shutter 94 may increase the energy consumption of the entire vehicle. This will be described with reference to FIGS.

[0042] FIG. 3 shows changes in energy consumption required for air conditioning. In FIG. 3, line ST_CL shows energy consumption for air conditioning when the grill shutter 94 is closed, and line ST_OP shows energy consumption for air conditioning when the grill shutter 94 is closed. As is clear from FIG. 3, when the grill shutter 94 is closed (in the case of ST_CL), energy consumption is not significantly affected by vehicle speed V. However, in this example, a sub-radiator 56 is also provided in addition to the main radiator 54. As vehicle speed V increases, the heat exchange efficiency in the sub-radiator 56 increases, so energy consumption ST_CL gradually decreases as vehicle speed V increases, even when the grill shutter 94 is closed.

[0043] When the grille shutter 94 is open, the efficiency of heat exchange with the outside air increases more significantly as the vehicle speed V increases, resulting in a more significant decrease in air conditioning energy consumption. Hereinafter, the increase in air conditioning energy consumption when the grille shutter 94 is closed compared to when it is open (i.e., the difference between ST_OP and ST_CL) will be referred to as the "air conditioning energy increase amount Eac." This air conditioning energy increase amount Eac increases as the vehicle speed V increases. The air conditioning energy increase amount Eac also changes depending on the outside temperature. Normally, the higher the outside temperature, the greater the air conditioning energy increase amount Eac.

[0044] Fig. 4 is a diagram showing the relationship between the air conditioning energy increase amount Eac and the aerodynamic energy increase amount Ead. In Fig. 4, the solid line indicates the aerodynamic energy increase amount Ead. Also, in Fig. 4, the dashed line Eac_Tn indicates the air conditioning energy increase amount Eac at the outside air temperature T = Tn. In Fig. 4, T4 > T3 > T2 > T1.

[0045] As is clear from FIG. 3, as the vehicle speed V increases, both the increase amount of air-conditioning energy Eac and the increase amount of aerodynamic energy Ead increase. However, the rate of increase with respect to the vehicle speed V is higher for the increase amount of aerodynamic energy Ead than for the increase amount of air-conditioning energy Eac. Therefore, when the vehicle speed V exceeds a certain value, the increase amount of aerodynamic energy Ead exceeds the increase amount of air-conditioning energy Eac. For example, when the outside air temperature T = T2, when V ≦ Va, Eac ≧ Ead, but when V > Va, the magnitude relationship between the increase amount of aerodynamic energy Ead and the increase amount of air-conditioning energy Eac is reversed, and Eac < Ead.

[0046] Here, when Eac < Ead, closing the grill shutter 94 to reduce aerodynamic drag can keep the energy consumption of the entire vehicle lower than when it is open. Also, when Eac ≧ Ead, opening the grill shutter 94 to improve the heat exchange rate with the outside air can keep the energy consumption of the entire vehicle lower than when it is closed.

[0047] Therefore, in this example, the grill shutter 94 is opened and closed in consideration of the magnitude relationship between the increase amount of air-conditioning energy Eac and the increase amount of aerodynamic energy Ead. This will be described below with reference to FIG. 5. FIG. 5 is a flowchart showing the flow of opening and closing control of the grill shutter 94 during air-conditioning operation.

[0048] In the example of FIG. 5, the opening and closing of the grill shutter 94 is controlled based on the vehicle speed V, a first parameter, and a second parameter. Here, the first parameter is a parameter representing the load of the compressor 24, for example, the pressure (refrigerant pressure P) or temperature of the first refrigerant at the outlet of the compressor 24. Also, the second parameter is a parameter representing the temperature of the surrounding environment of the air-conditioning system 10 or the temperature of the temperature control target, for example, the outside air temperature T, the temperature inside the vehicle cabin, the temperature of the evaporator 30 during cooling operation, the temperature of the heater core 60 during heating operation, etc.

[0049] 5, the outside air temperature T is treated as the first parameter, and the refrigerant pressure P is treated as the second parameter. As shown in FIG. 5, when air conditioning is being performed, the control device 90 first determines whether the outside air temperature T is equal to or lower than a specified reference temperature Tst (S10).

[0050] Here, the reference temperature Tst is not particularly limited. Usually, the reference temperature Tst is set to a temperature such that Eac>Ead within the range of vehicle speeds V that a vehicle can generally assume. For example, in the example of FIG. 4, when T≧T3, Eac>Ead within almost the entire range of vehicle speeds V. Therefore, in this case, a value equal to or greater than T3 may be set as the reference temperature Tst.

[0051] Furthermore, the reference temperature Tst may not be a single value but may be a value having a hysteresis characteristic. For example, as shown in Fig. 6, a first reference temperature Tst_lw and a second reference temperature Tst_hg higher than the first reference temperature Tst_lw may be set as the reference temperature Tst. In this case, the control device 90 may determine that the reference temperature Tst is exceeded when the outside air temperature T crosses the second reference temperature Tst_hg in an upward direction, and may determine that the outside air temperature T is equal to or lower than the reference temperature Tst when the outside air temperature T crosses the first reference temperature Tst_lw in a downward direction.

[0052] In either case, when the outside air temperature T exceeds the reference temperature Tst (No in S10), it is highly likely that the air conditioning energy increase Eac due to the closing of the grille shutter 94 will be greater than the aerodynamic energy increase Ead due to the opening of the grille shutter 94. In this case, opening the grille shutter 94 suppresses the energy consumption required for air conditioning, thereby reducing the energy consumption of the entire vehicle. Therefore, when the outside air temperature T exceeds the reference temperature Tst (No in S10), the control device 90 opens the grille shutter 94 regardless of the vehicle speed V or the refrigerant pressure P (S20).

[0053] On the other hand, if the outside air temperature T is equal to or lower than the reference temperature Tst (Yes in S10), the control device 90 subsequently compares the refrigerant pressure P with the reference load Pst (S12). If P>Pst (No in S12), the control device 90 determines that the load on the air conditioning system 10 is high and opens the grille shutter 94 (S20). Note that, like the reference temperature Tst, the reference load Pst may be a value with hysteresis rather than a single value. Furthermore, the reference load Pst may be a variable value that changes depending on the outside air temperature T, the vehicle speed V, or a combination of these.

[0054] When the refrigerant pressure P is equal to or lower than the reference load Pst (Yes in S12), the control device 90 opens and closes the grille shutter 94 in accordance with the vehicle speed V (S14 to S20). Specifically, the control device 90 stores in advance, for each outside air temperature T, the value of the vehicle speed V at which the aerodynamic energy increase amount Ead and the air conditioning energy increase amount Eac are balanced, as the switching vehicle speed threshold Vth. For example, in the example of Fig. 4, when the outside air temperature T=T2, the vehicle speed V=Va becomes the switching vehicle speed threshold Vth.

[0055] In step S14, the control device 90 identifies the switching vehicle speed threshold Vth for the current outside air temperature T. If the current vehicle speed V exceeds the switching vehicle speed threshold Vth (Yes in S16), the aerodynamic energy increase Ead caused by opening the grille shutter 94 is greater than the air conditioning energy increase Eac caused by closing the grille shutter 94. Therefore, if V>Vth, the control device 90 closes the grille shutter 94 (S18) to suppress aerodynamic resistance. This reduces the energy consumption of the entire vehicle.

[0056] On the other hand, if the current vehicle speed V is equal to or lower than the switching vehicle speed threshold Vth (No in S16), the air conditioning energy increase Eac due to the closing of the grille shutter 94 is greater than the aerodynamic energy increase Ead due to the opening of the grille shutter 94. Therefore, if V≦Vth, the control device 90 opens the grille shutter 94 (S20) to reduce the energy consumption required for air conditioning. This reduces the energy consumption of the entire vehicle.

[0057] Thereafter, the process returns to step S10, and the outside air temperature T and the refrigerant pressure P are monitored. If the outside air temperature T and the refrigerant pressure P exceed the reference temperature Tst and the reference load Pst, the grille shutter 94 is opened regardless of the vehicle speed V.

[0058] In this way, by controlling the opening and closing of the grille shutter 94 based on the outside air temperature T, the refrigerant pressure P, and the vehicle speed V, an excessive load is not placed on the compressor 24, and energy consumption of the entire vehicle can be reduced.

[0059] Next, other embodiments will be described. In the above example, the magnitude relationship between the air conditioning energy increase amount Eac and the aerodynamic energy increase amount Ead was estimated based on the vehicle speed V and the outside air temperature T. However, in reality, the air conditioning energy increase amount Eac also varies depending on other parameters, such as a target interior temperature specified by the user and the amount of heat generated by electronic devices such as the battery 82. Therefore, even if the outside air temperature T is T2, the change curve of the air conditioning energy increase amount Eac changes depending on the situation. For example, even if the outside air temperature T is the same T2, depending on the values ​​of the other parameters, the change curve of the air conditioning energy increase amount Eac may be line C3, line C2, or line C1 in FIG. 7.

[0060] Which of lines C1 to C3 the change curve of the air conditioning energy increase amount Eac is can be inferred to some extent from a first parameter representing the load on the compressor 24, such as the refrigerant pressure P at the outlet of the compressor 24. For example, when the outside air temperature T=T2, the vehicle speed V=Va, and the refrigerant pressure P is P1, it can be inferred that the air conditioning energy increase amount Eac will change as shown by line C1. Similarly, it can be inferred that the air conditioning energy increase amount Eac will change as shown by line C2 when T=T2, V=Va, and P=P2, and that it will change as shown by line C3 when T=T2, V=Va, and P=P3. Note that P3>P2>P1.

[0061] Here, in the example of FIG. 7, when T = T2 and V = Va, if P > P2, the increase in air-conditioning energy Eac becomes greater than the increase in aerodynamic energy Ead. In this case, opening the grille shutter 94 can suppress the energy consumption of the entire vehicle. Also, when T = T2 and V = Va, if P < P2, the increase in air-conditioning energy Eac becomes smaller than the increase in aerodynamic energy Ead. In this case, closing the grille shutter 94 can suppress the energy consumption of the entire vehicle. That is, in the state where T = T2 and V = Va, the value P2 can be regarded as the threshold for switching the opening and closing of the grille shutter 94, that is, the switching load threshold Pth.

[0062] In this example, such a switching load threshold Pth is obtained in advance for each of a plurality of ranges of the outside air temperature T and the vehicle speed V. FIG. 8 is a diagram showing an example of a switching load threshold table. In the example of FIG. 8, the outside air temperature T is divided into three temperature ranges: a low temperature range, a medium temperature range, and a high temperature range, and the vehicle speed V is divided into three speed ranges: a low speed range, a medium speed range, and a high speed range. And the switching load threshold Pth is set for each temperature range and each speed range. In the example of FIG. 8, the switching load threshold Pth has a hysteresis characteristic. Specifically, as the switching load threshold Pth, an opening threshold PO and a closing threshold PC smaller than the opening threshold PO are set. The control device 90 opens the grille shutter 94 when the refrigerant pressure P crosses the opening threshold PO in the upward direction, and closes the grille shutter 94 when the refrigerant pressure P crosses the closing threshold PC in the downward direction. For example, in the state of medium temperature and medium speed, when the refrigerant pressure P crosses the closing threshold PC22 in the decreasing direction, the grille shutter 94 is closed. On the other hand, in the state of medium temperature and medium speed, when the refrigerant pressure P crosses the opening threshold PO11 in the increasing direction, the grille shutter 94 is opened. Note that in the example of FIG. 8, when the vehicle speed V is in the low speed region or the outside air temperature T is in the high temperature region, the grille shutter 94 is always opened regardless of the refrigerant pressure P, so the switching load threshold Pth is not set in this region.

[0063] Next, the flow of opening and closing control of the grille shutter 94 using the table of Fig. 8 will be described with reference to Fig. 9. As shown in Fig. 9, when the vehicle speed V is in the low speed range or the outside air temperature T is in the high speed range (Yes in S30 or Yes in S32), the control device 90 opens the grille shutter 94 (S44). Furthermore, when the temperature of the third refrigerant immediately after passing through the oil cooler 73 (i.e., the temperature of the powertrain cooling refrigerant) is high (Yes in S34), the control device 90 also opens the grille shutter 94 (S44).

[0064] On the other hand, if the answer is No in step S34, the control device 90 compares the current vehicle speed V and outside air temperature T with the switching load threshold table of FIG. 8 to identify the switching load threshold Pth (i.e., the values ​​of the close threshold PC and the open threshold PO) corresponding to the current vehicle speed V and outside air temperature T (S36). Next, if the refrigerant pressure P crosses the open threshold PO in the upward direction (Yes in S38), the control device 90 opens the grille shutter 94 (S44). On the other hand, if the refrigerant pressure P crosses the close threshold PC in the downward direction (Yes in S40), the control device 90 closes the grille shutter 94 (S42). If the refrigerant pressure P does not cross either the open threshold PO or the close threshold PC, the grille shutter 94 is not switched between open and closed states and remains in its current state. The above process is then repeated until the air conditioning is turned off.

[0065] As is clear from the above explanation, in this example, the switching load threshold Pth is determined based on the vehicle speed V and the outside air temperature T, and the grille shutter 94 is opened or closed based on a comparison between the refrigerant pressure P and the switching load threshold Pth. With this configuration, it is possible to more accurately determine the magnitude relationship between the air conditioning energy increase amount Eac and the aerodynamic energy increase amount Ead, and it is possible to more reliably reduce energy consumption throughout the vehicle.

[0066] In the above description, the refrigerant pressure P is used as the first parameter and the outside air temperature T is used as the second parameter. However, these may be changed as appropriate. For example, the refrigerant temperature detected by the temperature sensor 40 may be used as the first parameter instead of the refrigerant pressure P. Furthermore, the temperature inside the vehicle cabin, the temperature of the evaporator 30 during cooling operation, or the temperature of the heater core 60 during heating operation may be used as the second parameter instead of the outside air temperature T. Furthermore, the configuration described above is merely an example, and other configurations may be changed as long as the opening and closing of the grille shutter 94 is controlled based on at least the vehicle speed V, the first parameter, and the second parameter. For example, the aerodynamic energy increase amount Ead may be estimated based on the vehicle speed V, and the air conditioning energy increase amount Eac may be estimated based on the first parameter and the second parameter. The grille shutter 94 may be closed if Ead > Eac, and opened if Ead ≦ Eac.

[0067] Furthermore, as long as the air conditioning system 10 has at least the compressor 24, the main radiator 54, and the grille shutter 94, other components may be changed. Therefore, for example, the sub-radiator 56 may be omitted. Also, the second refrigerant circuit 50 and the third refrigerant circuit 70 may be omitted. In this case, in the first refrigerant circuit 20, the main radiator 54 may be provided instead of the condenser 26, and a heater core 60 may be provided instead of the chiller 32. [Explanation of symbols]

[0068] 10 air conditioning system, 20 first refrigerant circuit, 24 compressor, 26 condenser, 28 modulator, 30 evaporator, 32 chiller, 34a, 34b expansion valve, 36, 64 three-way valve, 64 three-way valve, 38 pressure sensor, 40 temperature sensor, 50 second refrigerant circuit, 54 main radiator, 56 sub-radiator, 58, 76 pump, 60 heater core, 62 heater, 64 three-way valve, 70 third refrigerant circuit, 73 oil cooler, 74 low-temperature radiator, 80 five-way valve, 82 battery, 90 control device, 92 grill opening, 94 grill shutter, 96 temperature sensor.

Claims

1. A control device that controls the opening and closing of a grill shutter incorporated in an in-vehicle air conditioning system, The vehicle air conditioning system includes: a compressor that compresses a first refrigerant; a main radiator disposed behind a grill opening and configured to exchange heat between the first refrigerant or a second refrigerant that exchanges heat with the first refrigerant and outside air; the grill shutter that opens and closes the grill opening; Equipped with the control device opens and closes the grill shutter based on a first parameter representing a load on the compressor, a second parameter representing a temperature of an ambient environment or a temperature control target of the vehicle air conditioning system, and a vehicle speed; the first parameter is a pressure of the first refrigerant or a temperature of the first refrigerant at an outlet of the compressor; the second parameter is an outside air temperature; The control device specifying a value of the first parameter at which the grill shutter should be switched between open and closed based on the vehicle speed and the second parameter as a switching load threshold; opening and closing the grille shutter according to a comparison result between the actual measured value of the first parameter and the switching load threshold value; A grill shutter control device characterized by:

2. The grill shutter control device according to claim 1, the switching load threshold is a value of the first parameter when an increase in aerodynamic energy and an increase in air conditioning energy are balanced, the aerodynamic energy increase amount is an increase in energy consumption caused by an increase in aerodynamic resistance when the grill shutter is open compared to when the grill shutter is closed, The air conditioning energy increase amount is an increase in energy consumption caused by an increase in air conditioning load when the grill shutter is closed compared to when the grill shutter is open. A grill shutter control device characterized by:

3. The grill shutter control device according to claim 1, The switching load threshold includes an open threshold and a close threshold lower than the open threshold, The control device opens the grille shutter when the actual measured value of the first parameter crosses the opening threshold in an increasing direction, and closes the grille shutter when the actual measured value of the first parameter crosses the closing threshold in a decreasing direction. A grill shutter control device characterized by:

4. The grill shutter control device according to any one of claims 1 to 3, The grille shutter control device is characterized in that the vehicle air conditioning system further comprises a sub-radiator that is provided in a position that is not affected by the opening and closing of the grille shutter and that exchanges heat between the first refrigerant or the second refrigerant and outside air.

5. A control device for a grill shutter as described in claim 1, The vehicle air conditioning system further includes an oil cooler that exchanges heat between a lubricating oil for a transaxle and a third refrigerant, the control device opens the grille shutter regardless of the value of the first parameter when the temperature of the third refrigerant immediately after passing through the oil cooler is equal to or higher than a specified refrigerant temperature, or the vehicle speed is equal to or lower than a specified speed, or the second parameter is equal to or higher than a predetermined temperature. A grill shutter control device characterized by:

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