Vehicle, vehicle control method, and program

Abstract

The present invention comprises: a pump (13) that adjusts the flow rate of a first temperature-control medium flowing through a first circulation path (11) including a first flow path (20), which passes through a power conversion device (4) that supplies electric power to a drive source (2) of a vehicle, and a second flow path (21), which bypasses the power conversion device (4); a valve (15) that adjusts a flow rate distribution of the first temperature-control medium with respect to the first flow path (20) and the second flow path (21); and a control unit (19). The control unit (19) performs drive force limiting control for limiting drive force of the vehicle on the basis of the temperature of the first temperature-control medium or the temperature of the power conversion device (4), and sets a control commencement temperature at which to commence the drive force limiting control on the basis of the state of the pump (13) and / or the state of the valve (15).

Description

Vehicle, vehicle control method, and program

[0001] The present invention relates to a vehicle, a vehicle control method, and a program.

[0002] In recent years, initiatives aimed at realizing a low-carbon or carbon-neutral society have become active, and research and development on electrification technologies have been conducted for vehicles as well, in order to reduce CO₂ emissions and improve energy efficiency.

[0003] The power conversion device described in Patent Document 1 is mounted on an automobile that uses a motor as a driving source, and supplies electric power to the motor. When the output current from the power conversion device exceeds a predetermined value and this state continues for a predetermined time, the output current is limited, and the predetermined time is set to be longer as the temperature of the cooling body is lower.

[0004] Japanese Unexamined Patent Application Publication No. 2006-025493

[0005] In the power conversion device described in Patent Document 1, an allowable duration for which the output current exceeds a predetermined value is set based on the temperature of the cooling body. For this reason, even when there is remaining capacity for cooling the power conversion device, there is a possibility that the output current may be limited, and there is a risk that sufficient driving force cannot be obtained.

[0006] One object of the present invention is to utilize the remaining cooling capacity to bring out the capability of the power conversion device and obtain sufficient driving force.

[0007] A vehicle according to one aspect of the present invention includes: a power conversion device that supplies electric power to a driving source of the vehicle; a first circulation path that includes a first flow passage passing through the power conversion device and a second flow passage bypassing the power conversion device, and circulates a first temperature control medium; a pump that adjusts a flow rate of the first temperature control medium flowing through the first circulation path; a valve that adjusts a flow rate distribution of the first temperature control medium to the first flow passage and the second flow passage; and a control unit that controls the pump and the valve, wherein the control unit executes driving force limitation control for limiting driving force of the vehicle based on a temperature of the first temperature control medium flowing through the first flow passage or a temperature of the power conversion device, and sets a control start temperature at which the driving force limitation control is started based on at least one of a state of the pump and a state of the valve.

[0008] Furthermore, a vehicle control method according to one aspect of the present invention is a vehicle control method comprising: a power converter that supplies power to a vehicle's drive source; a first circulation path that circulates a first temperature-controlled medium, including a first flow path that passes through the power converter and a second flow path that bypasses the power converter; a pump that adjusts the flow rate of the first temperature-controlled medium flowing through the first circulation path; and a valve that adjusts the flow rate distribution of the first temperature-controlled medium to the first flow path and the second flow path, wherein a processor mounted on the vehicle performs a drive force limiting control that limits the driving force of the vehicle based on the temperature of the first temperature-controlled medium flowing through the first circulation path or the temperature of the power converter, and sets a control start temperature to initiate the drive force limiting control based on at least one of the state of the pump and the state of the valve.

[0009] Furthermore, a program according to one aspect of the present invention causes a processor to execute the vehicle control method.

[0010] According to the present invention, the cooling surplus can be utilized to maximize the performance of the power conversion device, thereby obtaining sufficient driving force.

[0011] This is a block diagram of an example vehicle for illustrating embodiments of the present invention. This is a table showing an example of setting the control start temperature for initiating drive force limit control. This is a graph schematically showing an example of drive force limit control. This is a flowchart showing the process performed by the control unit, including setting the control start temperature. This is a flowchart showing the process performed by the control unit, including setting the control start temperature. This is a flowchart showing the process performed by the control unit, including setting the control start temperature. This is a flowchart showing the process performed by the control unit, including setting the control start temperature.

[0012] An example of a vehicle for illustrating embodiments of the present invention will be described based on the attached drawings.

[0013] The vehicle 1 shown in Figure 1 is an electric vehicle, such as an electric car or a hybrid vehicle (including a plug-in hybrid vehicle). The vehicle 1 comprises a motor 2 as a drive source, a battery, and an inverter 4. The inverter 4 includes a plurality of switching elements, which convert the DC current from the battery to AC current by turning the plurality of switching elements ON / OFF, and the converted AC current is supplied to the motor 2 to rotate the motor 2, thereby outputting the driving force of the vehicle 1 to the motor 2. The inverter 4 is configured to acquire the output request for driving force to the motor 2 based on the acceleration and deceleration operations of the occupants of the vehicle 1, and to supply power to the motor 2 according to the output request.

[0014] Vehicle 1 includes an inverter 4 and a cooling circuit for cooling a drive unit including a motor 2. The drive unit may also include a transmission, and in the case of a hybrid vehicle, it may further include a generator.

[0015] The cooling circuit includes a first circulation path 11 for circulating a first temperature-controlled medium for cooling the inverter 4, and a second circulation path 12 for circulating a second temperature-controlled medium for cooling the drive unit. The first temperature-controlled medium is, for example, water, and may have ethylene glycol or propylene glycol added from the viewpoint of antifreeze, corrosion prevention, rust prevention, etc. The second temperature-controlled medium is, for example, oil.

[0016] Vehicle 1 further comprises a first pump 13, a second pump 14, a valve 15, a heat exchanger 16, a radiator 17, an active grill shutter 18, and a control unit 19 as elements constituting the cooling circuit.

[0017] The first circulation path 11 includes a first flow path 20 that passes through the inverter 4 and a second flow path 21 that bypasses the inverter 4. The first flow path 20 and the second flow path 21 branch off at a branching section 22 in the first circulation path 11 and merge at a merging section 23, with a common flow path 24 between the merging section 23 and the branching section 22.

[0018] The first pump 13 is located in the common flow path 24, and a tank 25 for temporarily storing the first temperature-controlled medium is provided on the suction side of the first pump 13 in the common flow path 24. The first pump 13 changes its discharge rate according to its operating duty cycle and adjusts the flow rate of the first temperature-controlled medium flowing through the first circulation path 11. The operating duty cycle of the first pump 13 may change continuously, but in this example, it is set to change in steps such as low duty, medium duty, and high duty. The first pump 13 may be an electric pump equipped with a motor, or a mechanical pump driven by an engine.

[0019] Valve 15 is provided at the inlet to the second flow path 21 in the branch section 22. Valve 15 changes the flow rate of the first temperature-controlled medium flowing into the second flow path 21 according to its opening degree, and adjusts the flow rate distribution of the first temperature-controlled medium to the first flow path 20 and the second flow path 21. In this example, valve 15 is switchable between a closed state and an open state. When valve 15 is closed, all of the first temperature-controlled medium flowing through the first circulation path 11 is distributed to the first flow path 20. When valve 15 is open, a portion of the first temperature-controlled medium flowing through the first circulation path 11 is distributed to the second flow path 21, and the remainder is distributed to the first flow path 20.

[0020] The radiator 17 is located in the common flow path 24 between the first pump 13 and the branch section 22. The radiator 17 exchanges heat between the first temperature-controlled medium flowing through the common flow path 24 and the outside air, thereby cooling the first temperature-controlled medium. A temperature sensor 26 is provided on the outlet side of the radiator 17 in the common flow path 24, and the temperature sensor 26 detects the temperature of the first temperature-controlled medium that has passed through the radiator 17.

[0021] The active grille shutter 18 is provided at the air intake of the front grille and / or front bumper of the vehicle 1. The active grille shutter 18 is opened and closed to regulate the outside air flowing into the radiator 17.

[0022] The second pump 14 is located in the second circulation path 12, and a tank 27 for temporarily storing the second temperature-controlled medium is provided on the suction side of the second pump 14 in the second circulation path 12. The second pump 14 changes its discharge rate according to its operating duty cycle, adjusting the flow rate of the second temperature-controlled medium flowing through the second circulation path 12. The second pump 14 may be an electric pump equipped with a motor, or a mechanical pump driven by an engine. A temperature sensor 28 is provided in the tank 27, and the temperature sensor 28 detects the temperature of the second temperature-controlled medium stored in the tank 27.

[0023] The heat exchanger 16 is installed across the second flow path 21 and the second circulation path 12 of the first circulation path 11. The heat exchanger 16 performs heat exchange between the first temperature-controlled medium flowing through the second flow path 21 and the second temperature-controlled medium flowing through the second circulation path 12, thereby cooling the second temperature-controlled medium.

[0024] The control unit 19 is mainly composed of a processor and, by executing a predetermined program, controls the operating duty cycle of the first pump 13, the operating duty cycle of the second pump 14, the opening and closing of the valve 15, and the opening and closing of the active grill shutter 18 based on the temperature of the first temperature control medium detected by the temperature sensor 26 and the temperature of the second temperature control medium detected by the temperature sensor 28.

[0025] For example, if the inverter 4 increases the power supplied to the motor 2 in response to an increase in the output demand for driving force to the motor 2, the inverter 4 will generate heat, and the temperature of the first temperature control medium that cools the inverter 4 will rise. In response to the rise in the temperature of the first temperature control medium, the control unit 19 increases the operating duty cycle of the first pump 13, increases the flow rate of the first temperature control medium flowing through the first flow path 20, and strengthens the cooling of the inverter 4.

[0026] When the inverter 4 increases the power supplied to the motor 2, and the motor 2 increases its output, the motor 2 generates heat, and the temperature of the second temperature-controlled medium that cools the motor 2 rises. In response to the rise in temperature of the second temperature-controlled medium, the control unit 19 increases the operating duty cycle of the second pump 14, increasing the flow rate of the second temperature-controlled medium flowing through the second circulation path 12, thereby strengthening the cooling of the motor 2. Also, in response to the rise in temperature of the second temperature-controlled medium, the control unit 19 opens the valve 15, distributing a portion of the first temperature-controlled medium flowing through the first circulation path 11 to the second flow path 21, and cooling the second temperature-controlled medium by heat exchange between the first and second temperature-controlled medium in the heat exchanger 16.

[0027] As the inverter 4 and the second temperature control medium cool down, the temperature of the first temperature control medium rises to a predetermined temperature. At this point, the control unit 19 opens the active grill shutter 18 to increase the heat exchange between the first temperature control medium and the outside air in the radiator 17, thereby promoting the cooling of the first temperature control medium.

[0028] Furthermore, the control unit 19 can perform power-saving control to limit the vehicle's driving force and prevent overheating and damage to the switching elements of the inverter 4, based on the temperature of the first temperature-controlled medium or the temperature of the inverter 4. The control unit 19 then sets a control start temperature at which power-saving control is initiated, based on at least one of the state of the first pump 13 and the state of the valve 15.

[0029] By setting the control start temperature for initiating power-saving control based on the state of the first pump 13 and the state of the valve 15, it is possible to suppress the execution of power-saving control while the inverter 4 still has cooling capacity remaining, thereby maximizing the use of the inverter 4's capabilities. The limitation of the vehicle's driving force may be limited by restricting the power supplied by the inverter 4 to the motor 2, or by limiting the driving force output by the motor 2. The following explanation will use the limitation of the power supplied by the inverter 4 to the motor 2 as an example.

[0030] Figure 2 shows an example of setting the control start temperature.

[0031] The control unit 19 sets the control start temperature according to the cooling capacity of the inverter 4. The cooling capacity of the inverter 4 is related to whether or not the flow rate of the first temperature-controlled medium flowing through the first flow path 20 of the first circulation path 11 can be increased, and the flow rate of the first temperature-controlled medium flowing through the first flow path 20 is related to the operating duty cycle of the first pump 13 and the open / closed state of the valve 15.

[0032] As shown in Figure 2, the control unit 19 sets the control start temperature to the first temperature Ta1 if it can increase the discharge rate of the first pump 13 and the flow rate of the first temperature-controlled medium in the first flow path 20 can be increased by the valve 15 to a predetermined amount or more. In this example, where the operating duty cycle of the first pump 13 changes in stages from low duty to medium duty to high duty, increasing the discharge rate of the first pump 13 means operating the first pump 13 in high duty. Also, in this example, where the valve 15 can be switched between a closed state and an open state, increasing the flow rate of the first temperature-controlled medium in the first flow path 20 by the valve 15 means closing the valve 15. On the other hand, if the control unit 19 cannot increase the discharge rate of the first pump 13 and the flow rate of the first temperature-controlled medium in the first flow path 20 cannot be increased by the valve 15 to a predetermined amount or more, it sets the control start temperature to the second temperature Ta2, which is lower than the first temperature Ta1 (Ta2 < Ta1).

[0033] Furthermore, the control unit 19 sets the control start temperature to the third temperature Ta3 if the discharge amount of the first pump 13 can be increased and the flow rate of the first temperature-controlled medium in the first flow path 20 cannot be increased to a predetermined amount or more by the valve 15, and sets the control start temperature to the fourth temperature Ta4 if the discharge amount of the first pump 13 cannot be increased and the flow rate of the first temperature-controlled medium in the first flow path 20 can be increased to a predetermined amount or more by the valve 15. The third temperature Ta3 and the fourth temperature Ta4 are higher than the second temperature Ta2 and lower than the first temperature Ta1 (Ta2 < Ta3 and Ta4 < Ta1).

[0034] When the flow rate of the first temperature-controlled medium flowing through the first channel 20 can be increased by the first pump 13 and valve 15, raising the control start temperature suppresses the execution of power-saving control while the inverter 4 has remaining cooling capacity, making it possible to utilize the inverter 4's capacity to the fullest.

[0035] Preferably, the third temperature Ta3 is higher than the fourth temperature Ta4 (Ta2 < Ta4 < Ta3 < Ta1). The opening and closing of valve 15 is directly related to the cooling of the second temperature-controlled medium that cools the motor 2. The operating duty cycle of the first pump 13 is less constrained by the cooling of the second temperature-controlled medium than that of valve 15, allowing for more flexible settings. Therefore, when the flow rate of the first temperature-controlled medium can be increased by the first pump 13, setting the control start temperature relatively high further suppresses the execution of power-saving control while leaving cooling capacity in the inverter 4, making it possible to utilize the inverter 4's capacity to the fullest.

[0036] Figure 3 schematically shows the change in power supplied by the inverter 4 to the motor 2, which is limited by power-saving control.

[0037] When the control start temperature is set to one of the first temperature Ta1, second temperature Ta2, third temperature Ta3, and fourth temperature Ta4, and the temperature of the first temperature-controlled medium detected by the temperature sensor 26 reaches the set control start temperature, the control unit 19 performs power-saving control. In power-saving control, the control unit 19 lowers the upper limit of the power that the inverter 4 can supply to the motor 2 as the temperature of the first temperature-controlled medium rises from the control start temperature. The upper limit of power determines the upper limit of the driving force that the motor 2 can output.

[0038] Before power-saving control is initiated, the upper limit of power that the inverter 4 can supply to the motor 2 is defined as W0. Regardless of whether the control start temperature is the first temperature Ta1, the second temperature Ta2, the third temperature Ta3, or the fourth temperature Ta4, when the temperature of the first temperature-controlled medium reaches Tupper, the upper limit of power becomes W1 (W1 < W0), and the upper limit of power is fixed at W1 when the temperature of the first temperature-controlled medium is Tupper or higher.

[0039] For example, when the control start temperature is set to the first temperature Ta1, the rate of decrease in the power limit with respect to the temperature rise of the first temperature control medium after the start of power saving control is relatively large, but the temperature range in which the power limit is maintained at W0 is relatively long, and during that time, even if the output demand for driving force to the motor 2 temporarily increases based on, for example, the acceleration and deceleration operations of the occupants, it is possible to respond to the output demand by utilizing the cooling surplus capacity of the inverter 4.

[0040] In the example shown in Figure 3, the control start temperature at which power saving control is initiated was described as being set in relation to the temperature of the first temperature control medium. However, the temperature of the inverter 4 and the temperature of the first temperature control medium that cools the inverter 4 are related, and therefore, the control start temperature may also be set in relation to the temperature of the inverter 4.

[0041] Figures 4 to 7 show an example of the process performed by the control unit 19, including setting the control start temperature.

[0042] Motor 2 is cooled by a second temperature-controlled medium flowing through a second circulation path 12, and the second temperature-controlled medium is cooled by heat exchange with the first temperature-controlled medium in the heat exchanger 16. Valve 15 regulates the flow rate of the first temperature-controlled medium flowing through a second flow path 21 passing through the heat exchanger 16, and the opening and closing of valve 15 is related to the temperature of the second temperature-controlled medium. Therefore, the temperature of the second temperature-controlled medium is related to the cooling capacity of the inverter 4. Also, as the driving force output by motor 2 increases, the heat generated by motor 2 increases, and the temperature of the second temperature-controlled medium rises. Therefore, the output requirement for driving force to motor 2 is also related to the cooling capacity of the inverter 4. The control unit 19 sets a control start temperature for initiating power-saving control, taking into consideration the temperature of the second temperature-controlled medium and the output requirement for driving force to motor 2.

[0043] Furthermore, the first temperature adjustment medium that cools the inverter 4 and the second temperature adjustment medium is cooled by heat exchange with outside air in the radiator 17. Opening the active grille shutter 18 promotes cooling of the first temperature adjustment medium in the radiator 17. However, from the perspective of suppressing a decrease in the aerodynamic performance of the vehicle 1, the control unit 19 opens the active grille shutter 18 when it is necessary to forcibly cool the first temperature adjustment medium, for example, and basically keeps the active grille shutter 18 in a closed state. The control unit 19 sets a control start temperature for starting power save control with the active grille shutter 18 kept in the closed state.

[0044] First, when the vehicle 1 starts traveling, the control unit 19 keeps the active grille shutter 18 closed, and operates the first pump 13 at low duty, middle duty, or high duty in accordance with the temperature TW of the first temperature adjustment medium (step S1). Then, the control unit 19 acquires the temperature TATF of the second temperature adjustment medium, and determines whether or not the temperature TATF of the second temperature adjustment medium is equal to or higher than a first predetermined temperature TATF1 (step S2).

[0045] When the temperature TATF of the second temperature adjustment medium is lower than the first predetermined temperature TATF1 (step S2-No), the control unit 19 determines that the priority of cooling the motor 2 is low, that is, the valve 15 can be kept in a closed state (step S10), and sets a control start temperature for starting power save control. In setting this control start temperature, the control unit 19 sets the control start temperature to be higher as the temperature TATF of the second temperature adjustment medium is lower, and sets the control start temperature to be lower as the temperature TATF of the second temperature adjustment medium is higher.

[0046] For example, when a first threshold value TATFth1 and a second threshold value TATFth2 (TATFth1 < TATFth2 < TATF1) related to the temperature TATF of the second temperature adjustment medium are used, and the temperature TATF of the second temperature adjustment medium is less than the first threshold value TATFth1 (step S11—Yes), a control start temperature is set to Tb1 (step S12). When the temperature TATF of the second temperature adjustment medium is equal to or higher than the first threshold value TATFth1 and less than the second threshold value TATFth2 (step S13—Yes), the control start temperature is set to Tb2 which is lower than Tb1 (Tb1 > Tb2) (step S14). Then, when the temperature TATF of the second temperature adjustment medium is equal to or higher than the second threshold value TATFth2 (step S13—No), the control start temperature is set to Tb3 which is higher than a second temperature Ta2 and lower than Tb2 (Tb1 > Tb2 > Tb3 > Ta2) (step S15).

[0047] Following the temperature rise of the inverter 4, the temperature of the motor 2 rises. When the temperature TATF of the second temperature adjustment medium that cools the motor 2 is high, the temperature rise can be suppressed by starting power save control from an early stage (a lower temperature). Thereby, after performing thermal protection for both the inverter 4 and the motor 2, it is possible to suppress execution of the power save control in a state where a surplus cooling capacity of the inverter 4 remains.

[0048] Returning to step S2, when the temperature TATF of the second temperature adjustment medium is equal to or higher than a first predetermined temperature TATF1 (step S2—Yes), the control unit 19 further determines whether or not the temperature TATF of the second temperature adjustment medium is less than a second predetermined temperature TATF2 that is higher than the first predetermined temperature TATF1 (TATF1 < TATF2) (step S3).

[0049] When the temperature TATF of the second temperature control medium is equal to or greater than the second predetermined temperature TATF2 (step S3-No), the control unit 19 determines that cooling the motor 2 has a high priority, opens the valve 15, increases the flow rate of the first temperature control medium flowing through the second flow path 21, and sets the control start temperature for starting power saving control (step S20). Since the valve 15 is in the open state, the control start temperature set in step S20 becomes the second temperature Ta2 or the third temperature Ta3, depending on the operating duty cycle of the first pump 13, which is determined based on the temperature TW of the first temperature control medium.

[0050] When the temperature of the second temperature control medium is high, above the second predetermined temperature TATF2, priority is given to cooling the motor 2, the valve 15 is opened to increase the flow rate of the first temperature control medium flowing through the second flow path 21, and a control start temperature is set to initiate power save control. This protects the inverter 4 and motor 2 from heat, while also preventing power save control from being executed while there is still cooling capacity remaining for the inverter 4.

[0051] Next, the control unit 19 determines whether the requested drive force output MotTq for the motor 2 is equal to or greater than a predetermined drive force MotTq1 (step S21). If the requested drive force MotTq is less than the predetermined drive force MotTq1 (step S21-No), the control unit 19 controls the first pump 13 and the valve 15 in normal operation (step S22). In normal operation, the control unit 19 operates the first pump 13 in low duty, medium duty, or high duty according to the temperature TW of the first temperature control medium. The control unit 19 also opens the valve 15 when the temperature TATF of the second temperature control medium reaches a third predetermined temperature TATF3 (TATF1 < TATF3 < TATF2) which is higher than the first predetermined temperature TATF1 and lower than the second predetermined temperature TATF2.

[0052] If the output request MotTq is equal to or greater than the predetermined driving force MotTq1 (step S21-Yes), the control unit 19 determines whether the temperature TW of the first temperature-controlled medium is equal to or greater than the second temperature Ta2 (step S23). If the temperature TW of the first temperature-controlled medium is less than the second temperature Ta2 (step S23-No), the control unit 19 controls the first pump 13 and valve 15 normally (step S22). On the other hand, if the temperature TW of the first temperature-controlled medium is equal to or greater than the second temperature Ta2 (step S23-Yes), the control unit 19 forces the first pump 13 to operate on high duty to increase the flow rate of the first temperature-controlled medium flowing through the first circulation path 11 and sets a control start temperature to initiate power-saving control (step S24). Since the first pump 13 is operated on high duty and the valve 15 is in the open state, the control start temperature set in step S24 becomes the third temperature Ta3. Until the output request MotTq falls below the predetermined driving force MotTq1, or the temperature TW of the first temperature control medium falls below the second temperature Ta2, the control unit 19 maintains the operating duty cycle of the first pump 13 at high duty cycle and keeps the valve 15 open.

[0053] Returning to step S3, if the temperature TATF of the second temperature control medium is less than the second predetermined temperature TATF2 (step S3-Yes), the control unit 19 determines whether the output request MotTq for the driving force to the motor 2 is greater than or equal to the predetermined driving force MotTq1 (step S4). If the output request MotTq is less than the predetermined driving force MotTq1 (step S4-No), the control unit 19 controls the first pump 13 and valve 15 normally (step S5). On the other hand, if the output request MotTq is greater than or equal to the predetermined driving force MotTq1 (step S4-Yes), the control unit 19 determines whether the temperature TW of the first temperature control medium is greater than or equal to the second temperature Ta2 (step S6).

[0054] If the temperature TW of the first temperature-controlled medium is less than the second temperature Ta2 (step S6-No), the control unit controls the first pump 13 and valve 15 normally (step S5). On the other hand, if the temperature TW of the first temperature-controlled medium is equal to or greater than the second temperature Ta2 (step S6-Yes), the control unit 19 determines that cooling the inverter 4 has a high priority and further determines whether the temperature TW of the first temperature-controlled medium is equal to or greater than a predetermined temperature TW1 (Ta2 < TW1) which is higher than the second temperature Ta2 (step S7).

[0055] If the temperature TW of the first temperature-controlled medium is equal to or greater than a predetermined temperature TW1 (step S7-Yes), the control unit 19 forces the first pump 13 to operate on high duty cycle and closes the valve 15 to increase the flow rate of the first temperature-controlled medium in the first flow path 20, thereby strengthening the cooling of the inverter 4. Then, based on the state of the first pump 13 and the state of the valve 15, the control unit 19 sets the control start temperature at which power-saving control will begin (step S8). Since the operating duty cycle of the first pump 13 is set to high duty cycle and the valve 15 is closed, the control start temperature set in step S8 is the first temperature Ta1.

[0056] If the temperature TW of the first temperature-controlled medium is less than a predetermined temperature TW1 (step S7-No), the control unit 19 closes the valve 15 and increases the flow rate of the first temperature-controlled medium in the first flow path 20 using the valve 15 to enhance the cooling of the inverter 4. Then, based on the state of the first pump 13 and the state of the valve 15, the control unit 19 sets the control start temperature at which power-saving control will begin (step S9). Since the valve 15 is in the closed state, the control start temperature set in step S9 will be either the first temperature Ta1 or the fourth temperature Ta4, depending on the operating duty cycle of the first pump 13 determined based on the temperature TW of the first temperature-controlled medium.

[0057] When a relatively high driving force of MotTq1 or higher is required, the temperature of the inverter 4 tends to rise. In such a situation, the operating duty cycle of the first pump 13 is forcibly increased and / or the valve 15 is forcibly closed, increasing the flow rate of the first temperature-controlled medium in the first flow path 20, and enhancing the cooling of the inverter 4. Based on the state of the first pump 13 and the state of the valve 15, a control start temperature for initiating power-saving control is set. However, if the temperature of the first temperature-controlled medium is low, the first pump 13 and the valve 15 are normally controlled to provide sufficient cooling performance. This suppresses the power consumption of the first pump 13 and the decrease in the cooling performance of the motor 2 due to the adjustment of the valve 15, while enabling appropriate power-saving control when necessary.

[0058] The control start temperature set in steps S8 and S9 is preferably set to a temperature higher than or equal to the temperature of the first temperature control medium at which the operating duty cycle of the first pump 13 is set to high duty cycle under normal control. This raises the control start temperature to a temperature at which sufficient cooling performance of the inverter 4 can be ensured, thereby preventing power-saving control from being performed while there is cooling capacity remaining in response to output requests.

[0059] Furthermore, the control start temperature set in steps S8 and S9 is preferably set to a temperature higher than the temperature at which the active grill shutter 18 opens. When the flow rate of the first temperature control medium flowing through the first flow path 20 can be increased by the first pump 13 and valve 15, changing the control start temperature to a temperature higher than the opening temperature of the active grill shutter 18 allows the flow rate of the first temperature control medium to be increased by the first pump 13 and valve 15 even in the shutter closed state where the temperature tends to rise, thereby improving the cooling performance of the inverter 4 and ensuring vehicle performance. In other words, vehicle performance is prioritized and the reduction in driving force is suppressed until the shutter opening temperature is reached, and then cooling of the inverter 4 is prioritized once the shutter opening temperature is reached. This makes it possible to set power-saving control so that the capacity of the inverter 4 can be utilized to the maximum extent while ensuring vehicle performance.

[0060] Next, the control unit 19 determines whether the requested drive force output MotTq for the motor 2 is equal to or greater than a predetermined drive force MotTq1 (step S30). If the requested drive force MotTq is less than the predetermined drive force MotTq1 (step S30-No), the control unit 19 controls the first pump 13 and valve 15 normally (step S31). On the other hand, if the requested drive force MotTq is equal to or greater than the predetermined drive force MotTq1 (step S30-Yes), the control unit 19 maintains the closed state of valve 15 set in step S8 or step S9 for a predetermined period (step S32).

[0061] When a relatively high driving force of MotTq1 or higher is required, maintaining the closed state of the valve 15 for a predetermined period allows priority to be given to cooling the inverter 4. This increases the output driving force and prevents the driving force limiting control from being executed while there is still cooling capacity remaining for the inverter 4 in response to the output request.

[0062] When a predetermined period has elapsed and the temperature TATF of the second temperature-controlled medium has reached or exceeded the second predetermined temperature TATF2 (step S32-Yes), the control unit 19 controls the first pump 13 and valve 15 in normal mode (step S31). By keeping the valve 15 closed, the flow of the first temperature-controlled medium in the second flow path is blocked, and the temperature of the second temperature-controlled medium rises over time. Therefore, on the condition that the temperature of the second temperature-controlled medium reaches or exceeds the second predetermined temperature TATF2, the control of the first pump 13 and valve 15 returns to normal control.

[0063] Although embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and modifications, improvements, etc., can be made as appropriate. This specification includes at least the following matters. Note that the components etc. in parentheses indicate those corresponding to the above embodiments, but the invention is not limited thereto.

[0064] (1) A vehicle comprising: a power converter (inverter 4) that supplies power to a drive source (motor 2) of a vehicle (vehicle 1); a first circulation path (first circulation path 11) that circulates a first temperature-controlled medium, including a first flow path (first flow path 20) that passes through the power converter and a second flow path (second flow path 21) that bypasses the power converter; a pump (first pump 13) that adjusts the flow rate of the first temperature-controlled medium flowing through the first circulation path; a valve (valve 15) that adjusts the flow rate distribution of the first temperature-controlled medium to the first flow path and the second flow path; and a control unit (control unit 19) that controls the pump, the valve, and the power converter, wherein the control unit performs a drive force limiting control that limits the driving force of the vehicle based on the temperature of the first temperature-controlled medium flowing through the first circulation path or the temperature of the power converter, and sets a control start temperature to initiate the drive force limiting control based on at least one of the state of the pump and the state of the valve.

[0065] According to the vehicle described in (1) above, by setting the control start temperature at which the drive force limit control begins based on the pump state and valve state, it is possible to suppress the execution of the drive force limit control while there is still cooling capacity remaining in the power converter, thereby making maximum use of the power converter's capacity.

[0066] (2) The vehicle according to (1) above, wherein the control unit sets the control start temperature to a first temperature when it can increase the discharge amount of the pump and can increase the flow rate of the first temperature control medium in the first flow path to a predetermined amount or more by the valve, and sets the control start temperature to a second temperature when it cannot increase the discharge amount of the pump and cannot increase the flow rate of the first temperature control medium in the first flow path to a predetermined amount or more by the valve, and the first temperature is higher than the second temperature.

[0067] According to the vehicle described in (2) above, when the flow rate of the first temperature-controlled medium flowing through the first channel can be increased by the pump and valve, raising the control start temperature prevents the driving force limit control from being performed while there is cooling capacity remaining in the power converter, making it possible to make maximum use of the power converter's capacity.

[0068] (3) The vehicle according to (2) above, wherein the control unit sets the control start temperature to a third temperature that is higher than the second temperature and lower than the first temperature when the discharge amount of the pump can be increased and the flow rate of the first temperature control medium in the first flow path cannot be increased by the valve and the control start temperature to a fourth temperature that is higher than the second temperature and lower than the first temperature when the discharge amount of the pump cannot be increased and the flow rate of the first temperature control medium in the first flow path can be increased by the valve and higher than the first temperature, and the third temperature is higher than the fourth temperature.

[0069] According to the vehicle described in (3) above, when the flow rate of the first temperature control medium can be increased by the pump, setting the control start temperature relatively high further suppresses the execution of drive force limiting control while the power converter has cooling capacity remaining, making it possible to make maximum use of the power converter's capacity.

[0070] (4) The vehicle according to (1) above, further comprising: a second circulation path (second circulation path 12) that passes through the drive source and circulates the second temperature control medium; and a heat exchanger (heat exchanger 16) that performs heat exchange between the first temperature control medium flowing through the second circulation path and the second temperature control medium flowing through the second circulation path, wherein the control unit sets the control start temperature higher as the temperature of the second temperature control medium decreases.

[0071] According to the vehicle described in (4) above, the temperature of the power converter rises, followed by a rise in the temperature of the drive source. However, if the temperature of the second temperature control medium that cools the drive source is high, the temperature rise can be suppressed by starting the drive force limit control at an earlier stage (lower temperature). This prevents the drive force limit control from being executed while the power converter has remaining cooling capacity, after both the power converter and the drive source have been thermally protected.

[0072] (5) The vehicle according to (4) above, wherein the control unit controls the valve such that when the temperature of the second temperature control medium is above a predetermined temperature, the flow rate of the first temperature control medium in the first flow path decreases and the flow rate of the first temperature control medium in the second flow path increases, and sets the control start temperature based on at least one of the state of the pump and the state of the valve.

[0073] According to the vehicle described in (5) above, when the temperature of the second temperature control medium is high above a predetermined temperature, priority is given to cooling the drive source, the flow rate of the first temperature control medium flowing through the second channel is increased by a valve, and a control start temperature is set to initiate the drive force limit control. This protects the power converter and drive source from heat, and prevents the drive force limit control from being executed while there is still cooling capacity remaining for the power converter.

[0074] (6) The vehicle according to (1) above, wherein the control unit sets the control start temperature based on at least one of the state of the pump and the state of the valve when the output request for driving force to the drive source is equal to or greater than a predetermined driving force.

[0075] According to the vehicle described in (6) above, when a relatively high driving force exceeding a predetermined driving force is required, the temperature of the power converter tends to rise. In such circumstances, by setting a control start temperature at which driving force limiting control is initiated based on the pump state and valve state, it is possible to suppress the decrease in the cooling performance of the drive source due to the power consumption of the pump and adjustment of the valve, and to perform appropriate driving force limiting control when necessary.

[0076] (7) The vehicle according to (6) above, wherein the first circulation path includes a common path (common path 24) between the discharge side of the pump and a branching section that branches into the first path and the second path, and the control unit controls the pump to increase the discharge amount of the pump and / or controls the valve to ensure that the flow rate of the first temperature-controlled medium in the first path is equal to or greater than a predetermined flow rate when the output request is equal to or greater than the predetermined driving force and the temperature of the first temperature-controlled medium in the common path is equal to or greater than a predetermined temperature.

[0077] According to the vehicle described in (7) above, when a relatively high driving force exceeding a predetermined driving force is required, the temperature of the power converter tends to rise. In such circumstances, the flow rate of the first temperature control medium in the first flow path is increased by the pump and / or valve, and a control start temperature for initiating driving force limiting control is set based on the state of the pump and the state of the valve. This suppresses the power consumption of the pump and the decrease in the cooling performance of the drive source due to valve adjustment, while enabling appropriate driving force limiting control when necessary.

[0078] (8) The vehicle according to (6) above, wherein the control unit controls the valve for a predetermined period of time such that the flow rate of the first temperature control medium in the first flow path is equal to or greater than a predetermined amount when the output request is equal to or greater than the predetermined driving force.

[0079] According to the vehicle described in (8) above, when a relatively high driving force exceeding a predetermined driving force is required, the state of the valve is maintained for a predetermined period such that the flow rate of the first temperature control medium in the first flow path increases, thereby prioritizing the cooling of the power converter. This allows for a larger output driving force and prevents the driving force limiting control from being executed while there is sufficient cooling capacity remaining for the power converter in response to the output request.

[0080] (9) The vehicle according to (6) above, wherein the first circulation path includes a common flow path between the discharge side of the pump and a branching section that branches into the first flow path and the second flow path, the control unit controls the discharge amount of the pump based on the temperature of the first temperature-controlled medium in the common flow path, and when the output request is equal to or greater than the predetermined driving force, controls the pump so that the discharge amount of the pump increases to a predetermined discharge amount, and sets the control start temperature to a temperature of the first temperature-controlled medium that is equal to or greater than the predetermined discharge amount under control based on the temperature of the first temperature-controlled medium.

[0081] According to the vehicle described in (9) above, the control start temperature can be raised to a temperature that ensures sufficient cooling performance for the power converter, thereby preventing the execution of drive force limiting control while there is still cooling capacity remaining for the output request.

[0082] (10) The vehicle according to (1) above, wherein the first circulation path includes a common path between the discharge side of the pump and a branching section that branches into the first flow path and the second flow path, the vehicle further comprises: a radiator (radiator 17) that performs heat exchange between the first temperature-controlled medium flowing through the common path and outside air, and a shutter (active grill shutter 18) that can be opened and closed to regulate the outside air flowing into the radiator, the control unit controls the opening and closing of the shutter based on the temperature of the first temperature-controlled medium in the common flow path, and sets the control start temperature based on at least one of the state of the pump and the state of the valve with the shutter in the closed state.

[0083] According to the vehicle described in (10) above, it is possible to suppress the deterioration of vehicle performance caused by opening the shutter and to prevent the execution of drive force limiting control while leaving cooling capacity in response to the output request.

[0084] (11) The vehicle according to (10) above, wherein the control unit sets the control start temperature higher than the temperature at which the shutter is opened when the output request for driving force to the drive source is equal to or greater than a predetermined driving force, the discharge amount of the pump can be increased and the flow rate in the first flow path can be increased to or greater than a predetermined flow rate by the valve.

[0085] According to the vehicle described in (11) above, vehicle performance is prioritized and a decrease in driving force is suppressed until the shutter opening temperature is reached, and once the shutter opening temperature is reached, cooling of the power converter is prioritized. This makes it possible to set the driving force limit control so that the capacity of the power converter can be utilized to the fullest extent while ensuring vehicle performance.

[0086] (12) The vehicle according to (1) above, wherein, in the driving force limiting control, the control unit limits the power supplied by the power converter to the drive source, or limits the driving force output by the drive source.

[0087] (13) A vehicle control method comprising: a power converter that supplies power to a vehicle's drive source; a first circulation path that circulates a first temperature-controlled medium, including a first flow path that passes through the power converter and a second flow path that bypasses the power converter; a pump that adjusts the flow rate of the first temperature-controlled medium flowing through the first circulation path; and a valve that adjusts the flow rate distribution of the first temperature-controlled medium to the first flow path and the second flow path, wherein a processor mounted on the vehicle performs a drive force limiting control that limits the driving force of the vehicle based on the temperature of the first temperature-controlled medium flowing through the first circulation path or the temperature of the power converter, and sets a control start temperature to initiate the drive force limiting control based on at least one of the state of the pump and the state of the valve.

[0088] (14) A program that causes the processor to execute the vehicle control method described in (13) above.

[0089] The present invention is suitably applicable to electric vehicles such as electric cars and hybrid vehicles (including plug-in hybrid vehicles).

[0090] 1 Vehicle 2 Motor 4 Inverter 11 First circulation path 12 Second circulation path 13 First pump 14 Second pump 15 Valve 16 Heat exchanger 17 Radiator 18 Active grill shutter 19 Control unit 20 First flow path 21 Second flow path 22 Branch section 23 Junction section 24 Common flow path 25 Tank 26 Temperature sensor 27 Tank 28 Temperature sensor

Claims

1. A vehicle comprising: a power converter that supplies power to the drive source of the vehicle; a first circulation path for circulating a first temperature-controlled medium, including a first flow path that passes through the power converter and a second flow path that bypasses the power converter; a pump that adjusts the flow rate of the first temperature-controlled medium flowing through the first circulation path; a valve that adjusts the flow rate distribution of the first temperature-controlled medium to the first flow path and the second flow path; and a control unit that controls the pump, the valve, and the power converter, wherein the control unit performs a drive force limiting control that limits the driving force of the vehicle based on the temperature of the first temperature-controlled medium flowing through the first circulation path or the temperature of the power converter, and sets a control start temperature for initiating the drive force limiting control based on at least one of the state of the pump and the state of the valve.

2. A vehicle according to claim 1, wherein the control unit sets the control start temperature to a first temperature when it can increase the discharge amount of the pump and the flow rate of the first temperature control medium in the first flow path can be increased to a predetermined amount or more by the valve, and sets the control start temperature to a second temperature when it cannot increase the discharge amount of the pump and the flow rate of the first temperature control medium in the first flow path cannot be increased to a predetermined amount or more by the valve, and the first temperature is higher than the second temperature.

3. The vehicle according to claim 2, wherein the control unit sets the control start temperature to a third temperature that is higher than the second temperature and lower than the first temperature when the discharge amount of the pump can be increased and the flow rate of the first temperature control medium in the first flow path cannot be increased by the valve and the flow rate of the first temperature control medium in the first flow path can be increased by the valve and the control start temperature is set to a fourth temperature that is higher than the second temperature and lower than the first temperature, and the third temperature is higher than the fourth temperature.

4. A vehicle according to claim 1, further comprising: a second circulation path that passes through the drive source and circulates a second temperature-controlled medium; a heat exchanger that performs heat exchange between the first temperature-controlled medium flowing through the second circulation path and the second temperature-controlled medium flowing through the second circulation path, wherein the control unit sets the control start temperature higher as the temperature of the second temperature-controlled medium decreases.

5. A vehicle according to claim 4, wherein the control unit controls the valve such that when the temperature of the second temperature-controlled medium is above a predetermined temperature, the flow rate of the first temperature-controlled medium in the first flow path decreases and the flow rate of the first temperature-controlled medium in the second flow path increases, and sets the control start temperature based on at least one of the state of the pump and the state of the valve.

6. A vehicle according to claim 1, wherein the control unit sets the control start temperature based on at least one of the state of the pump and the state of the valve when the output request for driving force to the drive source is equal to or greater than a predetermined driving force.

7. A vehicle according to claim 6, wherein the first circulation path includes a common path between the discharge side of the pump and a branching section that branches into the first flow path and the second flow path, and the control unit controls the pump to increase the discharge amount of the pump and / or controls the valve to ensure that the flow rate of the first temperature-controlled medium in the first flow path is equal to or greater than a predetermined flow rate when the output request is equal to or greater than a predetermined driving force and the temperature of the first temperature-controlled medium in the common flow path is equal to or greater than a predetermined temperature.

8. A vehicle according to claim 6, wherein the control unit controls the valve for a predetermined period of time such that the flow rate of the first temperature control medium in the first flow path is equal to or greater than a predetermined amount when the output request is equal to or greater than the predetermined driving force.

9. A vehicle according to claim 6, wherein the first circulation path includes a common path between the discharge side of the pump and a branching section that branches into the first flow path and the second flow path, the control unit controls the discharge amount of the pump based on the temperature of the first temperature-controlled medium in the common flow path, and when the output request is greater than or equal to the predetermined driving force, controls the pump so that the discharge amount of the pump increases to a predetermined discharge amount, and sets the control start temperature to a temperature of the first temperature-controlled medium that is greater than or equal to the predetermined discharge amount under control based on the temperature of the first temperature-controlled medium.

10. A vehicle according to claim 1, wherein the first circulation path includes a common path between the discharge side of the pump and a branching section that branches into the first flow path and the second flow path, the vehicle further comprises: a radiator that performs heat exchange between a first temperature-controlled medium flowing through the common path and outside air, and a shutter that can be opened and closed to regulate the outside air flowing into the radiator, the control unit controls the opening and closing of the shutter based on the temperature of the first temperature-controlled medium in the common path, and sets the control start temperature based on at least one of the state of the pump and the state of the valve with the shutter in the closed state.

11. A vehicle according to claim 10, wherein the control unit sets the control start temperature higher than the temperature at which the shutter is opened when the output request for driving force to the drive source is equal to or greater than a predetermined driving force, the discharge amount of the pump can be increased, and the flow rate in the first flow path can be increased to or greater than a predetermined flow rate by the valve.

12. A vehicle according to claim 1, wherein, in the driving force limiting control, the control unit limits the power supplied by the power converter to the drive source, or limits the driving force output by the drive source.

13. A vehicle control method comprising: a power converter that supplies power to the drive source of a vehicle; a first circulation path that circulates a first temperature-controlled medium, including a first flow path that passes through the power converter and a second flow path that bypasses the power converter; a pump that adjusts the flow rate of the first temperature-controlled medium flowing through the first circulation path; and a valve that adjusts the flow rate distribution of the first temperature-controlled medium to the first flow path and the second flow path, wherein a processor mounted on the vehicle performs a drive force limiting control that limits the driving force of the vehicle based on the temperature of the first temperature-controlled medium flowing through the first circulation path or the temperature of the power converter, and sets a control start temperature to initiate the drive force limiting control based on at least one of the state of the pump and the state of the valve.

14. A program that causes a processor to execute the vehicle control method described in claim 13.

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