JP7772662B2 - Hybrid vehicles - Google Patents

Description

The present invention relates to a hybrid vehicle, and more particularly to a hybrid vehicle equipped with an engine, a motor, first and second control devices, and first and second cooling devices.

Conventionally, hybrid vehicles of this type have been proposed that include an engine, a motor (motor generator), a control unit (PCU), and first and second cooling devices (see, for example, Patent Document 1). The engine and motor output power for driving. The control unit controls the motor. The first cooling device includes a first radiator and a first electric fan (first radiator fan). The first radiator exchanges heat with a cooling medium used to cool the engine. The first electric fan is used to cool the cooling medium in the first radiator. The second cooling device includes a second radiator and a second electric fan (second radiator fan). The second radiator exchanges heat with a cooling medium used to cool the motor and control unit. The second electric fan is used to cool the cooling medium in the second radiator and is controlled by the control unit. In this hybrid vehicle, when the temperature of the cooling medium in the second cooling device is above a predetermined temperature, the second electric fan is driven to lower the temperature of the cooling medium in the second cooling device. Furthermore, in this hybrid vehicle, even if the temperature of the cooling medium in the second cooling device is below a predetermined temperature, the second electric fan is driven when certain conditions are met. This improves the thermal environment in the engine compartment by blowing air from the second electric fan.

Japanese Patent Application Laid-Open No. 2019-119242

Generally, in hybrid vehicles equipped with a first control device that controls the engine and the first electric fan and a second control device that controls the motor and the second electric fan instead of the hybrid vehicle control device described above, when the ignition is turned off, the engine is stopped, the motor and the first and second electric fans are stopped, and the first and second control device systems are also stopped. If the engine's coolant temperature is high when the ignition is turned off and the engine is stopped, the first and second electric fans are not driven when the ignition is turned off, which can cause the coolant to reach a high temperature. One method to prevent this problem is to drive the first and second electric fans while the first and second control devices are active rather than shutting them down when the ignition is turned off. However, this method increases power consumption from the battery that supplies power to the first and second electric fans, the first control device, and the second control device, which can cause problems the next time the ignition is turned on.

The primary objective of the hybrid vehicle of the present invention is to reduce the consumption of power stored in the battery and to prevent the engine coolant from reaching high temperatures.

The hybrid vehicle of the present invention employs the following measures to achieve the above-mentioned primary objective.

The hybrid vehicle of the present invention is
An engine that outputs power for driving;
a motor that outputs power for driving;
a first control device that controls the engine;
a second control device that controls the motor;
a first cooling device including a first radiator for exchanging heat with a cooling medium for cooling the engine, and a first electric fan for cooling the cooling medium in the first radiator;
a second cooling device including a second radiator that exchanges heat with a cooling medium for cooling the motor and the second control device, and a second electric fan that cools the cooling medium in the second radiator;
a battery that supplies power to the first and second control devices and the first and second electric fans;
A hybrid vehicle comprising:
the second electric fan is disposed at a position facing the engine,
The second control device stops the system when the ignition is turned off,
The first control device drives the first and second electric fans when the temperature of the engine is equal to or higher than a predetermined temperature while the engine is stopped by turning off the ignition.

In this hybrid vehicle of the present invention, the second electric fan is positioned opposite the engine, and the second control device stops the system when the ignition is off. When the engine is stopped with the ignition off and the engine temperature is above a predetermined temperature, the first control device drives the first and second electric fans. Driving the first electric fan suppresses the temperature rise of the engine's cooling medium. Driving the second electric fan positioned opposite the engine cools the engine from the outside with airflow from the second electric fan. This suppresses the temperature rise of the cooling medium used to cool the engine due to heat dissipation from the engine. Driving the first and second electric fans using the first control device reduces consumption of power stored in the battery compared to when the first and second control devices drive the first and second electric fans. As a result, consumption of power stored in the battery is suppressed and the cooling medium used to cool the engine is prevented from reaching high temperatures.

In this hybrid vehicle of the present invention, the first control device and the second control device exchange information via communication, and when the ignition is on and there is no abnormality in the communication between the first control device and the second control device, the first control device drives the second electric fan based on the temperature of the cooling medium in the second cooling device received via communication from the second control device, and when the ignition is on and there is an abnormality in the communication between the first control device and the second control device, the first control device drives the second electric fan. This prevents the motor and the second control device from reaching high temperatures when there is an abnormality in the communication between the first control device and the second control device.

1 is a diagram showing an outline of the configuration of a hybrid vehicle 10 according to an embodiment of the present invention; 1 is a schematic diagram showing the general arrangement of an engine 11, a transaxle 12, radiators 23, 33, and fans 24, 34 in an engine room. 4 is a flowchart showing an example of a fan control routine executed by the engine ECU 40.

Next, we will explain how to implement the present invention using examples.

Figure 1 is a schematic diagram showing the overall configuration of a hybrid vehicle 10 according to one embodiment of the present invention. Figure 2 is a schematic diagram showing the overall layout of an engine 11, transaxle 12, radiators 23, 33, and fans 24, 34 in the engine compartment. The hybrid vehicle 10 of this embodiment includes the engine 11, transaxle 12, high-voltage battery 14, auxiliary battery (battery) 15, DC/DC converter 16, cooling devices (first and second cooling devices) 20, 30, an engine electronic control unit (hereinafter referred to as "engine ECU") (first control device) 40, and a hybrid electronic control unit (hereinafter referred to as "HVECU") (second control device) 50.

The engine 11 is configured as, for example, an internal combustion engine and outputs power for driving. As shown in Figure 2, the engine 11 is located in the engine compartment at the front of the hybrid vehicle 10, toward the left as viewed from the front of the hybrid vehicle 10.

As shown in Figures 1 and 2, the transaxle 12 includes a motor 120 and a power control unit (hereinafter referred to as "PCU") 122. As shown in Figure 2, the transaxle 12 is located in the engine compartment to the right of the engine 11 when viewed from the front of the hybrid vehicle 10. The motor 120, configured as, for example, a synchronous generator-motor, outputs power for driving the vehicle. The PCU 122 includes an inverter that converts DC power to AC power to drive the motor 120, a boost converter that boosts power from the high-voltage battery 14 and supplies it to the inverter, and a microcontroller unit that controls the inverter. The high-voltage battery 14, configured as, for example, a lithium-ion secondary battery or a nickel-metal hydride secondary battery, is connected to the PCU 122 via a high-voltage power line. The auxiliary battery 15, configured as, for example, a lithium-ion secondary battery, a nickel-metal hydride secondary battery, or a lead-acid battery, is connected to the low-voltage power line. The DC/DC converter 16 steps down the power from the high-voltage power line and supplies it to the low-voltage power line.

As shown in FIG. 1, the cooling system 20 is configured to cool the engine 11 and includes a coolant (cooling medium) circulation path 21, a water pump 22, a radiator (first radiator) 23, a fan (first electric fan) 24, and a motor 35. The circulation path 21 is formed by including the engine 11 and the radiator 23. The water pump 22 is provided in the circulation path 21 and is driven using power from the auxiliary battery 15 to circulate the coolant through the circulation path 21. As shown in FIG. 2, the radiator 23 is located in front of the transaxle 12 in the engine compartment and cools the coolant through heat exchange with the air generated by running wind and air generated by the fan 24. As shown in FIG. 2, the fan 24 is located in front of the transaxle 12, facing the transaxle 12, and behind the radiator 23. The fan 24 is driven by the motor 25 using power from the auxiliary battery 15 to blow air into the radiator 23 and cool the coolant in the radiator 23. The motor 25 is configured as, for example, a DC motor.

As shown in FIG. 1, the cooling device 30 is configured to cool the motor 120 and PCU 122, and includes a coolant circulation flow path 31, a water pump 32, a radiator (second radiator) 33, a fan (second electric fan) 34, and a motor 35. The circulation flow path 31 is formed by including the motor 120, the PCU 122, and the radiator 33. The water pump 32 is provided in the circulation flow path 31 and is driven by power from the auxiliary battery 15 to circulate the coolant through the circulation flow path 31. As shown in FIG. 2, the radiator 33 is disposed in front of the engine 11 in the engine compartment, next to the left of the radiator 23 when viewed from the front of the hybrid vehicle 10, and cools the coolant by heat exchange with the air generated by running wind and air generated by the fan 34. As shown in FIG. 2, the fan 34 is disposed in front of the engine 11, facing the engine 11, and behind the radiator 33, next to the left of the fan 24. It is driven to rotate by a motor 35 using power from the auxiliary battery 15 to blow air into the radiator 33 and cool the coolant in the radiator 33. The motor 35 is configured as, for example, a DC motor.

The engine ECU 40, although not shown, includes a microcomputer with a CPU, ROM, RAM, flash memory, input/output ports, and communication ports, and is connected to the low-voltage power line to which the auxiliary battery 15 and DC/DC converter 16 are connected. Various signals are input to the engine ECU 40 via input ports. Examples of signals input to the engine ECU 40 include signals from various sensors that detect the state of the engine 11, a coolant temperature Tw1 from the water temperature sensor 27 that detects the temperature of the coolant in the cooling device 20, and an ignition signal from the ignition switch (IG) 52. Various signals are output from the engine ECU 40 via output ports. Examples of signals output from the engine ECU 40 include various control signals for controlling the operation of the engine 11, a control signal for the water pump 22 of the cooling device 20, a control signal for the fan 24 (motor 25) of the cooling device 20, and a control signal for the fan 34 (motor 35) of the cooling device 30. The engine ECU 40 is communicatively connected to the HV ECU 50 via CAN communication.

Although not shown, the HVECU 50 includes a microcomputer having a CPU, ROM, RAM, flash memory, input/output ports, and communication ports, and is connected to the low-voltage power line to which the auxiliary battery 15 and DC/DC converter 16 are connected. Various signals are input to the HVECU 50 via the input port. Examples of signals input to the HVECU 50 include the coolant temperature Tw2 from the water temperature sensor 37, which detects the temperature of the coolant in the cooling device 30, and an ignition signal from the ignition switch 52. Various control signals are output from the HVECU 50 via the output port. Examples of signals output from the HVECU 50 include a control signal to the DC/DC converter 16 and a control signal to the water pump 32 of the cooling device 30. As described above, the HVECU 50 is communicatively connected to the engine ECU 40 via CAN communication.

In the cooling system 18 installed in the hybrid vehicle 10 of this embodiment configured as described above, the HVECU 50 basically controls the water pump 32 based on the coolant temperature Tw2 of the cooling device 30 from the water temperature sensor 37, and transmits the coolant temperature Tw2 to the engine ECU 40. The engine ECU 40 also controls the water pump 22 and fan 24 (motor 25) based on the coolant temperature Tw1 of the cooling device 20 from the water temperature sensor 27, and controls the fan 34 (motor 35) based on the coolant temperature Tw2 of the cooling device 30 from the HVECU 50. The water pump 22 and fan 24 are each controlled to stop when the coolant temperature Tw1 is below a threshold (predetermined temperature) Twth12, and to operate when the coolant temperature Tw1 is equal to or higher than the threshold Twth12. The water pump 32 and fan 34 are basically controlled to stop when the coolant temperature Tw2 is below the threshold value Twth22, and to operate when the coolant temperature Tw2 is equal to or higher than the threshold value Twth22.

When the ignition switch 52 is turned off and an off ignition signal is received, the engine ECU 40 and HVECU 50 basically stop driving the engine 11, motor 120, and PCU 122, and then shut down the system. Furthermore, when the ignition switch 52 is turned on and an on ignition signal is received, the engine ECU 40 and HVECU 50 basically start up the system.

Next, we will explain the operation of the hybrid vehicle 10 of this embodiment, particularly the control of the fan 34. Figure 3 is a flowchart showing an example of a fan control routine executed by the engine ECU 40. This routine is executed repeatedly.

When the fan control routine of Figure 3 is executed, the engine ECU 40 first determines whether an ON ignition signal is received from the ignition switch 52, i.e., whether the ignition switch 52 is ON (IG-ON) (step S100).

If the ignition switch 52 is turned on in step S100, the process then determines whether a communication abnormality has occurred with the HVECU 50 (step S110). This process is performed, for example, by determining whether communication with the HVECU 50 has been interrupted for a predetermined period of time. If communication with the HVECU 50 has not been interrupted for the predetermined period of time, it is determined that no communication abnormality has occurred with the HVECU 50. If communication with the HVECU 50 has been interrupted for the predetermined period of time, it is determined that a communication abnormality has occurred with the HVECU 50.

If no communication abnormality has occurred with the HVECU 50 in step S110, the coolant temperature Tw2 is input from the HVECU 50 via CAN communication (step S120), and it is determined whether the coolant temperature Tw2 is equal to or greater than the threshold value Twth22 (step S130). If the coolant temperature Tw2 is less than the threshold value Twth22, the fan 34 is stopped (step S140), and the routine ends. If the coolant temperature Tw2 is equal to or greater than the threshold value Twth22, the fan 34 is driven (step S150), and the routine ends.

If a communication abnormality occurs with the HVECU 50 in step S110, the fan 34 is driven (step S150), and this routine ends. If a communication abnormality occurs with the HVECU 50, the coolant temperature Tw2 cannot be input from the HVECU 50 via communication. As a result, the engine ECU 40 cannot properly determine whether the coolant circulating through the cooling device 30 is hot, and if the fan 34 is stopped, the motor 120 and PCU 122 may reach high temperatures. In this embodiment, if a communication abnormality occurs between the engine ECU 40 and the HVECU 50, the fan 34 is driven, thereby preventing the motor 120 and PCU 122 from reaching high temperatures.

If the ignition switch 52 is turned off in step S100, the engine ECU 40 executes the following process before shutting down the system.

First, the engine ECU 40 inputs the coolant temperature Tw1 (step S160) and determines whether the coolant temperature Tw1 is equal to or greater than the threshold value Twth12 (step S170).

If the coolant temperature Tw1 is less than the threshold value Twth12 in step S170, the fan 34 is stopped (step S180) and this routine ends. As described above, the fan 24 is stopped when the coolant temperature Tw is less than the threshold value Twth12, so step S180 stops the fans 24, 34. Once the fans 24, 34 are stopped in this way, the engine ECU 40 shuts down the system. After the system is shut down in this way, execution of this routine is suspended until the ignition switch 52 is turned on and the engine ECU 40 starts up.

If the coolant temperature Tw1 is equal to or greater than the threshold value Twth12 in step S170, the fan 34 is driven (step S190), and the routine ends. As described above, the fan 24 is driven when the coolant temperature Tw1 is equal to or greater than the threshold value Twth12, so step S190 is a process for driving the fans 24 and 34. Driving the fan 24 can suppress an increase in the temperature of the coolant in the cooling device 20 that cools the engine 11. Furthermore, driving the fan 34, which is positioned opposite the engine 11, can cool the engine 11 from the outside with the air blown by the fan 34, suppressing heat dissipation from the engine 11. This suppresses an increase in the temperature of the engine 11 coolant due to heat dissipation from the engine 11. When the ignition switch 52 is off, the HVECU 50 system is stopped, so step S190 involves driving the fans 24, 34 with the engine ECU 40 while the HVECU 50 system is stopped. This reduces the consumption of power stored in the auxiliary battery 15 compared to when both the HVECU 50 and the engine ECU 40 are started and the fans 24, 34 are driven. This reduces the consumption of power stored in the auxiliary battery 15 and also prevents the coolant that cools the engine 11 from reaching high temperatures.

In the hybrid vehicle 10 of the embodiment described above, the fan 34 is positioned facing the engine 11, and the HVECU 50 system is stopped when the ignition is off. When the ignition switch 52 is turned off and the engine 11 is stopped, if the coolant temperature Tw1 is equal to or higher than the threshold value Twth12, the fans 24, 34 are driven, thereby reducing consumption of power stored in the auxiliary battery 15 and preventing the coolant that cools the engine 11 from reaching high temperatures.

In the hybrid vehicle 10 of this embodiment, step S170 determines whether the coolant temperature Tw1 is equal to or greater than the threshold value Twth12. However, the temperature of the engine 11 may be detected instead of the coolant temperature Tw1, and a determination may be made as to whether the temperature of the engine 11 is equal to or greater than a predetermined temperature.

The following explains the correspondence between the main elements of the embodiment and the main elements of the invention described in the "Means for Solving the Problem" section. In the embodiment, the engine 11 corresponds to the "engine," the motor 120 corresponds to the "motor," the engine ECU 40 corresponds to the "first control device," the HVECU 50 corresponds to the "second control device," the cooling device 20 corresponds to the "first cooling device," the cooling device 30 corresponds to the "second cooling device," and the auxiliary battery 15 corresponds to the "battery."

The correspondence between the main elements of the Examples and the main elements of the invention described in the "Means for Solving the Problem" section does not limit the elements of the invention described in the "Means for Solving the Problem" section, as the Examples are examples used to specifically explain the form for implementing the invention described in the "Means for Solving the Problem" section. In other words, the interpretation of the invention described in the "Means for Solving the Problem" section should be based on the description in that section, and the Examples are merely specific examples of the invention described in the "Means for Solving the Problem" section.

The above describes the form for carrying out the present invention using examples, but the present invention is not limited to these examples in any way, and it goes without saying that the present invention can be embodied in various forms without departing from the spirit of the present invention.

This invention can be used in industries such as hybrid vehicle manufacturing.

10 Hybrid vehicle, 11 Engine, 12 Transaxle, 14 High-voltage battery, 15 Auxiliary battery, 16 DC/DC converter, 18 Cooling system, 20, 30 Cooling device, 21, 31 Circulation flow path, 22, 32 Water pump, 23, 33 Radiator, 24, 34 Fan, 25, 35, 120 Motor, 27, 37 Water temperature sensor, 40 Engine electronic control unit (Engine ECU), 50 Hybrid electronic control unit (HVECU), 52 Ignition switch, 122 Power control unit (PCU).

Claims (1)

An engine that outputs power for driving;
a motor that outputs power for driving;
a first control device that controls the engine;
a second control device that controls the motor;
a first cooling device including a first radiator for exchanging heat with a cooling medium for cooling the engine, and a first electric fan for cooling the cooling medium in the first radiator;
a second cooling device including a second radiator that exchanges heat with a cooling medium for cooling the motor and the second control device, and a second electric fan that cools the cooling medium in the second radiator;
a battery that supplies power to the first and second control devices and the first and second electric fans;
A hybrid vehicle comprising:
the second electric fan is disposed at a position facing the engine,
The second control device stops the system when the ignition is turned off,
The first control device drives the first and second electric fans when the temperature of the engine is equal to or higher than a predetermined temperature while the engine is stopped by turning off the ignition.