JP7825362B2 - vehicle - Google Patents

Description

The present invention relates to a vehicle.

Conventionally, vehicles using an engine and a motor as driving sources for traveling are known, and include an engine cooling system for cooling the engine and a hybrid cooling system for cooling a power transmission mechanism (hereinafter simply referred to as a "motor power transmission mechanism") that transmits power from the motor to the drivetrain (see, for example, Patent Document 1). Also known is a cooling water temperature control device that controls the activation/deactivation of an electric water pump and an electric cooling fan based on engine coolant temperature, engine speed, and output torque (see, for example, Patent Document 2). Patent Document 2 states that the cooling water temperature control device may be implemented using the vehicle's engine control unit (see paragraph 0026 of Patent Document 2). Furthermore, a cooling system is known that includes a rotating electrical machine cooling control device that activates a radiator fan 6 when the temperature of the coolant cooling the motor generator exceeds an activation temperature (see, for example, Patent Document 3). Patent Document 3 does not mention the engine, and it is clear that the cooling control device is not a so-called engine ECU, i.e., is controlled by, for example, a hybrid control device. Furthermore, it is known that the airflow rate of a cooling fan that cools a secondary battery is controlled by a hybrid control device (see, for example, Patent Document 4).

The engine cooling system and hybrid cooling system in the vehicle disclosed in Patent Document 1 each include a radiator. These radiators are located in the engine compartment along with the engine and the motor power transmission mechanism. The engine cooling system and hybrid cooling system each include a cooling fan for cooling the coolant flowing through the radiator. Each cooling fan is located opposite its corresponding radiator. The operating state of the cooling fan in the engine cooling system is controlled by an engine control device that executes various engine-related controls, for example, based on the temperature of the engine coolant, the exhaust temperature, and the temperatures of components that constitute or are associated with the engine, as exemplified in Patent Document 2. Meanwhile, the operating state of the cooling fan in the hybrid cooling system is controlled by a hybrid control device that performs power management, including the recovery of output and power in the motor power transmission mechanism , as exemplified in Patent Documents 3 and 4. The hybrid control device controls the operating state of the cooling fan based on, for example, the temperature of the hybrid coolant that cools the transaxle and PCU (Power Control Unit) included in the motor power transmission mechanism.

Japanese Patent Application Laid-Open No. 2019-119243 JP 2012-052504 A JP 2014-220912 A Japanese Patent Application Laid-Open No. 2007-196876

The engine compartment, where the engine and motor power transmission mechanism are located, can become very hot. However, the engine compartment temperature can be reduced by the operation of the cooling fans in the engine cooling system and hybrid cooling system. The engine is the primary heat source that raises the temperature in the engine compartment, and the temperature in the engine compartment is likely to rise when the engine generates a large amount of heat. Because the cooling fans in the engine cooling system are controlled by the engine control device, they can immediately start operating depending on the engine's status, making it easy to respond to temperature increases in the engine compartment. On the other hand, the cooling fans in the hybrid cooling system are controlled by the hybrid control device. Therefore, if the cooling fans in the hybrid cooling system are to be operated depending on the engine's status, for example, the engine control device must issue a command to drive the hybrid cooling system's cooling fans to the hybrid control device. This results in a time delay when the cooling fans in the hybrid cooling system are activated depending on the engine's status. As such, with conventional engine cooling systems and hybrid cooling systems, it has been difficult to immediately activate both cooling fans and responsively control the temperature in the engine compartment.

The vehicle disclosed in this specification therefore aims to responsively control the temperature inside the engine compartment, where the engine and motor power transmission mechanism are located.

The vehicle disclosed in this specification uses an engine and a motor as driving sources for traveling, and has the engine and a power transmission mechanism that transmits the power of the motor to a drivetrain located in an engine compartment. The vehicle is equipped with a first control device that controls the engine and a second control device that controls the power transmission mechanism that transmits the power of the motor. The vehicle is also equipped with a first radiator through which coolant that cools the engine circulates, a first electric fan that cools the first radiator, a second radiator through which coolant that cools the power transmission mechanism that transmits the power of the motor circulates, and a second electric fan that cools the second radiator, and the first control device controls the operation of the first electric fan and the second electric fan.

Furthermore, in a vehicle configured as described above, the first control device can be configured to operate the first electric fan and the second electric fan when exhaust-side temperature information related to the engine is equal to or greater than a predetermined threshold value related to exhaust-side temperature information.

Furthermore, in a vehicle configured as described above, the first control device can be configured to control the first electric fan based on the temperature of the coolant that cools the engine.

Furthermore, in a vehicle having the above configuration, the first control device can be configured to operate the first electric fan and the second electric fan when the temperature of the coolant that cools the engine is equal to or higher than a predetermined threshold value for the coolant temperature when the vehicle's power is turned off.

Furthermore, in a vehicle configured as described above, the second control device can be configured to request the first control device to operate the second electric fan based on the temperature of the coolant circulating through the second radiator, and the first control device can operate the second electric fan based on the operation request.

The vehicle disclosed in this specification allows for responsive control of the temperature inside the engine compartment, where the engine and motor power transmission mechanism are located.

FIG. 1 is a schematic diagram showing a schematic configuration inside an engine room of a vehicle according to an embodiment. FIG. 2 is a block diagram showing a control system for a cooling system provided in the vehicle according to the embodiment. FIG. 3 is a flowchart showing an example of control of the cooling system in the vehicle according to the embodiment. FIG. 4 is a graph showing an example of duty control of the ENG electric fan provided in the vehicle according to the embodiment. FIG. 5 is a graph showing an example of ON/OFF control of the HV electric fan provided in the vehicle according to the embodiment. FIG. 6 is a flowchart showing an example of control of the cooling system when the vehicle power supply of the vehicle according to the embodiment is turned off.

Embodiments of the present invention will be described below with reference to the accompanying drawings. However, the dimensions, proportions, etc. of each part in the drawings may not be illustrated to be exactly the same as the actual ones. Also, some details may be omitted in some drawings.

(Embodiment)
<Vehicles>
First, a vehicle 1 according to this embodiment and a schematic configuration of a cooling system in the vehicle 1 will be described with reference to Figures 1 and 2. Figure 1 schematically illustrates the interior of an engine compartment 2 of the vehicle 1. In the following description, the front-rear and left-right directions of the vehicle 1 are set as shown in Figure 1. The vehicle 1 according to this embodiment is a so-called hybrid electric vehicle (HEV) of a split type (series-parallel type), and uses an engine (ENG) 3 and a motor generator (MG) 4 as driving sources for traveling. The engine 3, the motor generator 4, a transaxle (T/A) 5, and a PCU 6 are arranged in the engine compartment 2 of the vehicle 1.

In this embodiment, the engine 3 is a gasoline engine, but it may also be a diesel engine.

The motor generator 4 has a DC brushless motor and functions as both a motor and a generator. In this embodiment, the motor generator 4 is housed in a case along with a planetary gear mechanism and a differential gear, and forms the transaxle 5, which transmits power to the drive wheels. The transaxle 5 is equipped with an oil cooler for cooling (or heating) the oil used in the transaxle 5. The PCU 6 incorporates an inverter and a microcontroller unit (microcomputer) for driving the motor generator 4.

The transaxle 5 and PCU 6 are included in a power transmission mechanism for transmitting the power of the motor generator 4 to a drivetrain including drive wheels (not shown). In the vehicle 1 of this embodiment, the engine 3 and motor generator 4 are connected to a planetary gear mechanism included in the transaxle 5, allowing the power from the engine 3 to be divided and distributed to the motor generator 4 and drive wheels. The power from the engine 3 and the power from the motor generator 4 can also be combined and transmitted to the drive wheels. It is also possible to stop the engine 3 and run the vehicle using only power from the motor generator 4.

Note that while this embodiment employs a split-type (series-parallel) hybrid system, the type of hybrid system is not limited to this and may be, for example, a series type or a parallel type. In a series type, engine power is converted into electricity by a generator, and the electricity generated by the generator is used to drive a drive motor, which then transmits power to the drive wheels. In a parallel type, a power split mechanism with a planetary gear mechanism is provided, and engine power and motor (motor generator) power are transmitted to the drive wheels.

The vehicle 1 is equipped with an engine radiator (hereinafter referred to as the "ENG radiator") 7 through which coolant circulates to cool the engine 3, and a hybrid radiator (hereinafter referred to as the "HV radiator") 9 through which coolant circulates to cool the transaxle 5 and PCU 6.

The ENG radiator 7 is located near the front right end of the engine compartment 2. The HV radiator 9 is located near the front left end of the engine compartment 2, side by side with the ENG radiator 7 in the left-right direction. The ENG radiator 7 corresponds to the first radiator, and the HV radiator 9 corresponds to the second radiator.

The ENG radiator 7 is connected to the engine 3 by a first pipe 7a and a second pipe 7b, and forms a coolant circulation path together with a water jacket (not shown) provided inside the engine 3. The first pipe 7a forms a path for coolant to flow from the engine 3 to the ENG radiator 7. The second pipe 7b forms a path for coolant to flow from the ENG radiator 7 to the engine 3. The coolant circulates between the engine 3 and the ENG radiator 7 by operating a water pump (not shown). Coolant cooled by the ENG radiator 7 is supplied to the engine 3.

The HV radiator 9 is connected to the transaxle 5 and PCU 6 by the third pipe 9a and fourth pipe 9b, forming a coolant circulation path between the transaxle 5 and PCU 6. The third pipe 9a forms a path for coolant to flow from the transaxle 5 and PCU 6 to the HV radiator 9. The fourth pipe 9b forms a path for coolant to flow from the HV radiator 9 to the transaxle 5 and PCU 6. The coolant circulates between the transaxle 5 and PCU 6 and the HV radiator 9 by operation of a water pump (not shown). Coolant cooled by the HV radiator 9 is supplied to the transaxle 5 and PCU 6.

An engine electric fan (hereinafter referred to as the "ENG electric fan") 8 is located behind the ENG radiator 7. The ENG electric fan 8 corresponds to the first electric fan and is located opposite the ENG radiator 7. When the ENG electric fan 8 is activated, it blows air toward the ENG radiator 7, cooling the ENG radiator 7 and ultimately cooling the coolant flowing through the ENG radiator 7. The ENG electric fan 8 is controlled using pulse width modulation (PWM), which controls its operating state based on the duty ratio.

A hybrid electric fan (hereinafter referred to as "HV electric fan") 10 is located behind the HV radiator 9. The HV electric fan 10 corresponds to the second electric fan and is located opposite the HV radiator 9. When the HV electric fan 10 is activated, it blows air toward the HV radiator 9, cooling the HV radiator 9 and ultimately cooling the coolant flowing through the HV radiator 9. In this embodiment, the HV electric fan 10 is controlled using an ON/OFF method, in which its operating state is controlled by switching ON/OFF, but the HV electric fan 10 may also be controlled using a PWM method.

Referring now to FIG. 2, the ENG electric fan 8 and the HV electric fan 10 are both controlled and driven by an engine control device (hereinafter referred to as the "ENG-ECU (Engine-Electronic Control Unit)") 11, which corresponds to the first control device. Specifically, a motor driver 8a for driving the motor 8b of the ENG electric fan 8 is electrically connected to the ENG-ECU 11, and the motor 8b is operated by a drive signal input from the ENG-ECU 11 to the motor driver 8a. Similarly, a motor driver 10a for driving the motor 10b of the HV electric fan 10 is electrically connected to the ENG-ECU 11, and the motor 10b is operated by a drive signal input from the ENG-ECU 11 to the motor driver 10a.

The ENG-ECU 11 is equipped with a CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), backup RAM, and other storage devices. The ENG-ECU 11 performs calculations and various controls based on programs and maps stored in the CPU, ROM, and other storage devices. The RAM is a memory that temporarily stores the results of calculations by the CPU and data input from various sensors, while the backup RAM is a non-volatile memory that stores data that needs to be saved when the engine 3 is stopped, etc. Sensors for controlling the ENG electric fan 8 and HV electric fan 10 are connected to the ENG-ECU 11. Specifically, a first water temperature sensor 21 that measures the temperature of the coolant circulating within the engine 3 and an exhaust temperature sensor 22 that measures the temperature of the exhaust gas discharged from the engine 3 are connected to the ENG-ECU 11. The ENG-ECU 11 is also equipped with a voltmeter 23 that measures the voltage applied to the ENG-ECU 11, and a timer 24 that measures the elapsed time since the vehicle 1 was powered off.

The ENG-ECU 11 performs various controls related to the operation of the engine 3, such as controlling the opening of a throttle valve (not shown) that adjusts the amount of air intake into the engine 3, and controlling the opening and closing of intake and exhaust valves (neither of which are shown). For this reason, the ENG-ECU 11 is connected to sensors for performing various controls other than those for the ENG electric fan 8 and HV electric fan 10, and stores various programs and maps, but a description of these will be omitted here.

The vehicle 1 is equipped with a hybrid control device (hereinafter referred to as the "HEV-ECU (Hybrid Electric Vehicle-Electronic Control Unit)") 12 in addition to the ENG-ECU 11. The HEV-ECU 12 corresponds to a second control device that controls the transaxle 5 and PCU 6. Because the transaxle 5 and PCU 6 are separate units from the engine 3, the HEV-ECU 12 is also provided separately from the ENG-ECU 11. It performs power management, including the recovery of power and output from the transaxle 5 and PCU 6. The HEV-ECU 12 is equipped with a CPU, RAM, ROM, backup RAM, and other storage devices, but its basic configuration is similar to that of the ENG-ECU 11, so a detailed description thereof will be omitted here.

A second water temperature sensor 25 is connected to the HEV-ECU 12, which measures the temperature of the coolant circulating between the transaxle 5, PCU 6, and HV radiator 9. The HEV-ECU 12 is capable of communicating with the ENG-ECU 11 via CAN (Controller Area Network) communication, and requests the ENG-ECU 11 to operate the HV electric fan 10 based on the measurement value of the second water temperature sensor 25. The ENG-ECU 11 operates the HV electric fan 10 based on the request from the HEV-ECU 12. In this way, the HV electric fan 10 may also operate based on an operation request from the HEV-ECU 12.

<ENG electric fan and HV electric fan control>
Here, the circumstances and ways in which the ENG electric fan 8 and the HV electric fan 10 operate will be described with reference to Table 1.

First, we will explain what happens when the vehicle 1 is powered on. When the vehicle 1 is powered on, the ignition is on, power is supplied to each part of the vehicle 1, and the engine 3 is running or ready to run. In this case, when the temperature of the engine components is high, the ENG electric fan 8 operates in the HI state, and the HV electric fan 10 is in the ON state, i.e., is in the operating state.

Here, the engine component temperature can be the temperature of a component in the engine 3 that is prone to becoming hot, specifically the surface temperature of the exhaust catalyst or exhaust manifold, or in some cases, the exhaust temperature. The surface temperatures of the exhaust catalyst and exhaust manifold, and the exhaust temperature are examples of exhaust-side temperature information. The exhaust-side temperature information is referenced because exhaust-related temperatures have a significant impact on the temperature in the engine compartment 2. The exhaust-side temperature information is included in the index for determining the state of the engine 3, and control may be performed based on other values that are correlated with these temperatures. In this embodiment, the exhaust temperature Tex of the engine 3 measured by the exhaust temperature sensor 22 is used. In this embodiment, the exhaust temperature Tex is measured and acquired by the exhaust temperature sensor 22. However, the exhaust temperature Tex may also be acquired, for example, using a map, based on the operating state of the engine 3, which is determined by the intake volume of the engine 3. In this embodiment, the engine component temperature is considered high when the exhaust temperature Tex is equal to or greater than a predetermined exhaust temperature threshold Texth. Since the exhaust temperature Tex is the temperature most likely to become high among the temperatures related to the engine 3, control based on the exhaust temperature Tex makes it easier to control the temperature in the engine compartment 2 with good responsiveness.

In addition, in this embodiment, the ENG electric fan 8 being in the HI state refers to a state in which the ENG electric fan 8 is operated at a duty ratio of 100%. In other words, in this embodiment, when the exhaust temperature Tex is equal to or higher than the threshold value Texth, the ENG electric fan 8 is operated at a duty ratio of 100%. However, the ENG electric fan 8's HI state does not necessarily have to be operated at a duty ratio of 100%; the duty ratio may be set appropriately, for example, to operate at a duty ratio of 95% or higher.

In this embodiment, when the exhaust temperature Tex is equal to or higher than the threshold value Texth, the ENG electric fan 8 is operated in the HIGH state and the HV electric fan 10 is operated in the ON state. When the exhaust temperature Tex is equal to or higher than the threshold value Texth, which indicates that the engine component temperature is high, it is likely that the temperature in the engine compartment 2 will also rise. The temperature in the engine compartment 2 is likely to affect the operation of the PCU 6 and other components located in the engine compartment 2. Therefore, when it is expected that the temperature in the engine compartment 2 will rise, the HV electric fan 10 is immediately operated along with the ENG electric fan 8 to lower the temperature in the engine compartment 2 or suppress that temperature rise. If the HV electric fan 10 is configured to operate in response to an operation command from the HEV-ECU 12, the ENG-ECU 11 must first request operation from the HEV-ECU 12 after acquiring the exhaust temperature Tex, which delays the start of operation of the HV electric fan 10. In this embodiment, the ENG electric fan 8 and HV electric fan 10 operate immediately, allowing for responsive control of the temperature inside the engine compartment 2.

Next, we will explain the case where the vehicle 1 is powered on and the engine coolant temperature Tengw is high, that is, the engine coolant temperature Tengw is equal to or higher than a predetermined threshold value Tengwth. In this case, the ENG electric fan 8 is duty-ratio controlled according to the engine coolant temperature Tengw. Note that in this case, the HV electric fan 10 column in Table 1 is left blank. This means that the HV electric fan 10 is not controlled by the engine coolant temperature Tengw, but does not mean that the HV electric fan 10 will not operate when the engine coolant temperature Tengw is high. As will be explained next, the HV electric fan 10 operates when the PCU coolant temperature Tpcuw is high, regardless of the engine coolant temperature Tengw.

Next, we will explain the case where the vehicle 1 is powered on and the PCU coolant temperature Tpcuw is high, that is, the PCU coolant temperature Tpcuw is equal to or higher than a predetermined threshold value Tpcuwth. In this case, the HV electric fan 10 can be turned on in response to the PCU coolant temperature Tpcuw. Note that in this case, the ENG electric fan 8 column in Table 1 is left blank. This means that the ENG electric fan 8 is not controlled by the PCU coolant temperature Tpcuw, but does not mean that the ENG electric fan 8 will not operate when the PCU coolant temperature Tpcuw is high.

Next, we will explain what happens when the vehicle 1 is powered off. When the vehicle 1 is powered off, it is expected that the temperature in the engine compartment 2 will rise depending on the vehicle 1's previous operating conditions. Therefore, in this embodiment, if the engine coolant temperature Tengw is equal to or greater than a predetermined threshold Tengwth' when the vehicle 1 is powered off, the ENG electric fan 8 is operated in a HIGH state and the HV electric fan 10 is turned ON. By immediately operating the ENG electric fan 8 and the HV electric fan 10 in this manner, the temperature rise in the engine compartment 2 can be reduced or suppressed. If the temperature in the engine compartment 2 rises during the soak period after the engine 3 is stopped, fuel remaining in the delivery pipe and injectors (neither shown) that supply fuel to the engine 3 may boil. If the fuel boils, misfires may occur when the engine is restarted after the soak period due to the so-called air entrapment phenomenon in the fuel. This phenomenon can be avoided by operating the ENG electric fan 8 and HV electric fan 10 when the vehicle 1 is powered off and responsively controlling the temperature inside the engine compartment 2.

In Table 1, when the ENG electric fan 8 is driven at HIGH, the ENG electric fan 8 is operated at a duty ratio of 100% in all cases. However, the duty ratio may be varied in accordance with the exhaust temperature Tex or the engine coolant temperature Tengw, i.e., the duty ratio may be increased as these temperatures increase, providing more precise control.

Next, with reference to Figures 3 to 6, an example of specific control of the ENG electric fan 8 and the HV electric fan 10 will be described. For the sake of explanation, it will be assumed that the ENG electric fan 8 and the HV electric fan 10 are not operating at the start of control.

<When the vehicle's power is ON>
First, the case where the power supply to the vehicle 1 is ON will be described with reference to the flowchart shown in FIG. 3. In step S1, the ENG-ECU 11 determines whether the exhaust gas temperature Tex, which is the measurement value of the exhaust gas temperature sensor 22, is equal to or higher than a predetermined threshold value Texth. If the ENG-ECU 11 makes a positive determination (Yes determination) in step S1, the ENG-ECU 11 proceeds to step S2. In step S2, the ENG-ECU 11 activates the ENG electric fan 8 and the HV electric fan 10. This allows for responsive control of the temperature in the engine compartment 2. After executing step S2, the ENG-ECU 11 repeats the process from step S1.

If the ENG-ECU 11 makes a negative determination (No determination) in step S1, it proceeds to step S3. In step S3, the ENG-ECU 11 determines whether the engine coolant temperature Tengw is equal to or higher than the threshold value Tengwth. If the ENG-ECU 11 makes a positive determination in step S3, it proceeds to step S4. On the other hand, if the ENG-ECU 11 makes a negative determination in step S3, it skips step S4 and proceeds to step S5.

In step S4, the ENG-ECU 11 operates the ENG electric fan 8. Here, with reference to Figure 4, an example of the operation control of the ENG electric fan 8 executed in step S4 will be described.

Referring to Figure 4, when engine coolant temperature Tengw is lower than threshold value Tengwth, the duty ratio of ENG electric fan 8 is 0%, and ENG electric fan 8 is stopped. As engine coolant temperature Tengw rises from this state and reaches threshold value Tengwth, ENG-ECU 11 sets the duty ratio of ENG electric fan 8 to 30%. As engine coolant temperature Tengw approaches temperature Tengwth+1, which is 1°C higher than threshold value Tengwth, ENG-ECU 11 gradually increases the duty ratio, setting it to 70% at temperature Tengwth+1. When engine coolant temperature Tengw reaches temperature Tengwth+3, which is 3°C higher than threshold value Tengwth, ENG-ECU 11 sets the duty ratio to 100%.

On the other hand, when the engine coolant temperature Tengw drops from temperature Tengwth+3 to temperature Tengwth+1, the ENG-ECU 11 reduces the duty ratio from 100% to 70%. Furthermore, while the engine coolant temperature Tengw drops from temperature Tengwth+1 to the threshold value Tengwth, the duty ratio is gradually reduced from 70% to 30%. Then, when the engine coolant temperature Tengw drops from the threshold value Tengwth to temperature Tengwth-2, which is 2°C lower than the threshold value Tengwth, the ENG-ECU 11 reduces the duty ratio from 30% to 0%. The difference between the temperatures at which the duty ratio is increased and decreased is intended to avoid hunting in the control. After a positive determination is made in step S3, the operation of the ENG electric fan 8 continues based on the duty ratio control shown in the graph in Figure 4. Note that the duty ratio shown in Figure 4 is an example and can be changed as appropriate.

After the ENG-ECU 11 starts operation of the ENG electric fan 8 in step S4, or after making a negative determination in step S3, the ENG-ECU 11 proceeds to step S5. In step S5, the HEV-ECU 12 determines whether the PCU coolant temperature Tpcuw is equal to or higher than the threshold value Tpcuwth. If the HEV-ECU 12 makes a positive determination in step S5, it proceeds to step S6. On the other hand, if the HEV-ECU 12 makes a negative determination in step S5, it repeats the processing from step S1.

In step S6, the HEV-ECU 12 operates the HV electric fan 10. Here, with reference to Figure 5, an example of the operation control of the ENG electric fan 8 executed in step S4 will be described.

Referring to Figure 5, when the PCU coolant temperature Tpcuw is lower than the threshold value Tpcuwth, the HV electric fan 10 is in the OFF state and is stopped. When the PCU coolant temperature Tpcuw rises from this state and reaches the threshold value Tpcuwth, the HEV-ECU 12 turns on the drive signal for the HV electric fan 10. This ON signal is sent from the HEV-ECU 12 to the ENG-ECU 11 via CAN communication as a request to operate the HV electric fan 10. Upon receiving this ON signal, the ENG-ECU 11 operates the HV electric fan 10.

On the other hand, when the PCU coolant temperature Tpcuw drops to a temperature Tpcuwth-2, which is 2°C lower than the threshold value Tpcuwth, the HEV-ECU 12 turns off the drive signal for the HV electric fan 10. This OFF signal is sent from the HEV-ECU 12 to the ENG-ECU 11 via CAN communication as a request to stop the HV electric fan 10. Upon receiving this OFF signal, the ENG-ECU 11 stops the HV electric fan 10.

Here, the activation of the HV electric fan 10 in step S6 is performed via CAN communication between the ENG-ECU 11 and the HEV-ECU 12. Therefore, there is a possibility that the activation of the HV electric fan 10 in step S6 will be delayed compared to the activation of the HV electric fan 10 in step S2. This is because the activation of the HV electric fan 10 in step S6 is considered less important in terms of immediacy than the activation of the HV electric fan 10 in step S2. The reason for this is explained below. First, the activation of the HV electric fan 10 in step S2 is based on the need to responsively control the temperature in the engine compartment 2. More specifically, the activation of the HV electric fan 10 in step S2 is due to the temperature rise in the engine compartment 2 caused by the operation of the engine 3, which has a rapid temperature rise rate and a large heat capacity. In contrast, the activation of the HV electric fan 10 in step S6 is primarily intended to cool the HV radiator 9. For this reason, even if the activation of the HV electric fan 10 in step S6 is slightly delayed compared to the activation of the HV electric fan 10 in step S2, this does not pose a significant problem. For these reasons, this embodiment employs a configuration in which the HV electric fan 10 is activated by the ENG-ECU 11.

Note that CAN communication is one example of a communication method between the ENG-ECU 11 and the HEV-ECU 12, and other communication methods may also be used.

After step S6 is executed, control of the vehicle 1 repeats the process from step S1. Note that once a positive determination is made in step S5, operation of the HV electric fan 10 continues based on the ON/OFF control shown in the graph in Figure 5.

<When the vehicle's power is off>
Next, referring to FIG. 6 , a case where the power supply to the vehicle 1 is turned off will be described. First, in step S11, the ENG-ECU 11 determines whether the power supply to the vehicle 1 is turned off and whether the voltage applied to the ENG-ECU 11 is equal to or greater than a reference value VO [V]. The voltage applied to the ENG-ECU 11 is a value measured by the voltmeter 23. The voltage applied to the ENG-ECU 11 is determined in order to determine whether the ENG-ECU 11 is in a state where it can execute a predetermined calculation. If the ENG-ECU 11 makes a positive determination in step S11, it proceeds to step S12. On the other hand, if the ENG-ECU 11 makes a negative determination in step S11, it terminates the processing (END). In conjunction with the execution of step S11, the ENG-ECU 11 starts counting the elapsed time t since the power supply to the vehicle 1 was turned off using the timer 24.

In step S12, the ENG-ECU 11 determines whether the engine coolant temperature Tengw immediately before the vehicle 1 was powered off is equal to or higher than the threshold value Tengwth'. If the ENG-ECU 11 determines yes in step S12, it proceeds to step S13; on the other hand, if the ENG-ECU 11 determines no in step S12, it ends the processing (END).

In step S13, the ENG-ECU 11 operates the ENG electric fan 8 and the HV electric fan 10. This allows for responsive control of the temperature inside the engine compartment 2. After the vehicle 1 is powered off, the ENG electric fan 8 and the HV electric fan 10 operate using the auxiliary battery (not shown) as a power source.

In step S14, which follows step S13, the ENG-ECU 11 determines whether the elapsed time t since the vehicle 1 was powered off is equal to or greater than a predetermined reference time t0 [sec]. If the ENG-ECU 11 determines yes in step S14, it proceeds to step S15. If the ENG-ECU 11 determines no in step S14, it repeats the process of step S14. In step S15, the ENG-ECU 11 stops the ENG electric fan 8 and the HV electric fan 10. The reason for stopping the ENG electric fan 8 and the HV electric fan 10 when the elapsed time t exceeds the reference time t0 [sec] is to prevent the auxiliary battery from deteriorating if these electric fans are operated for a long period of time. The reference time t0 [sec] is set taking into account the degree of deterioration of the auxiliary battery when the ENG electric fan 8 and the HV electric fan 10 are operated by the auxiliary battery. In step S15, the ENG-ECU 11 stops the ENG electric fan 8 and the HV electric fan 10, and then ends the series of processes (END).

In this embodiment, the vehicle 1 operates the ENG electric fan 8 and HV electric fan 10 for a certain period of time after the vehicle 1 is turned off, allowing for responsive control of the temperature in the engine compartment 2 even after the vehicle 1 is turned off.

In this embodiment, the vehicle 1 controls the drive of the ENG electric fan 8 and the HV electric fan 10 using the ENG-ECU 11, allowing for responsive control of the temperature in the engine compartment 2.

The vehicle 1 of this embodiment controls both the ENG electric fan 8 and the HV electric fan 10 based on the state of the engine 3, making it easy to control the temperature in the engine compartment 2 with good responsiveness.

In this embodiment, the vehicle 1 drives the ENG electric fan 8 and HV electric fan 10 when the exhaust temperature Tex of the engine 3, which tends to become high, is equal to or higher than a predetermined threshold Texth, thereby enabling more responsive control of the temperature in the engine compartment 2.

In this embodiment, the vehicle 1 controls the ENG electric fan 8 based on the engine 3 coolant temperature Tengw, so the ENG electric fan 8 can be operated based on the coolant temperature Tengw regardless of the exhaust temperature Tex, etc.

In the vehicle 1 of this embodiment, when the vehicle 1 is powered off, the ENG-ECU 11 operates the ENG electric fan 8 and the HV electric fan 10 if the engine coolant temperature Tengw is equal to or higher than the threshold value Tengwth'. This allows the temperature in the engine compartment 2 to be controlled with good responsiveness, even after the vehicle 1 is powered off.

In the vehicle 1 of this embodiment, the HEV-ECU 12 requests the ENG-ECU 11 to operate the HV electric fan 10 based on the PCU coolant temperature Tpcuw. The ENG-ECU 11 then operates the HV electric fan 10 based on the operation request. Therefore, the HV electric fan 10 can be operated based on the PCU coolant temperature Tpcuw regardless of the state of the engine 3.

The above embodiments are merely examples for implementing the present invention, and the present invention is not limited to these. Various modifications of these embodiments are within the scope of the present invention, and it is clear from the above description that various other embodiments are possible within the scope of the present invention.

1 Vehicle 2 Engine compartment 3 Engine 4 Motor generator 5 Transaxle 6 PCU
7 ENG radiator (first radiator)
8 ENG electric fan (first electric fan)
9 HV radiator (second radiator)
10 HV electric fan (second electric fan)
11 ENG-ECU (first control device)
12 HEV-ECU (second control device)
21 First water temperature sensor 22 Exhaust gas temperature sensor 25 Second water temperature sensor

Claims (4)

A vehicle using an engine and a motor as driving sources for traveling, the engine and a transaxle that transmits power of the motor to drive wheels are disposed in an engine room, and the vehicle is equipped with a first control device that controls the engine and a second control device that controls the transaxle that transmits power of the motor,
a first radiator through which cooling water for cooling the engine circulates;
a first electric fan that cools the first radiator;
a second radiator through which cooling water circulates to cool a transaxle that transmits power from the motor;
a second electric fan that cools the second radiator;
Equipped with
the first control device controls the driving of the first electric fan and the second electric fan , and when exhaust side temperature information related to the engine becomes equal to or higher than a predetermined threshold value related to exhaust side temperature information, issues an operation command to the first electric fan and the second electric fan at the same timing.
vehicle. 2. The vehicle according to claim 1 , wherein the first control device controls the first electric fan based on the temperature of a coolant that cools the engine. 3. The vehicle according to claim 1, wherein the first control device operates the first electric fan and the second electric fan when the temperature of the coolant that cools the engine is equal to or higher than a predetermined threshold value for the temperature of the coolant when the power of the vehicle is turned off. 4. The vehicle according to claim 1, wherein the second control device requests the first control device to operate the second electric fan based on the temperature of the cooling water circulating through the second radiator, and the first control device operates the second electric fan based on the operation request .