Hybrid vehicles

Abstract

The aim is to provide a hybrid vehicle that ensures driving performance in motor-driven mode while also ensuring cooling performance for the motor and power supply system. [Solution] A hybrid vehicle comprising: a fan that rotates in conjunction with the engine; a first motor connected to the engine and provided on a power transmission path between the engine and the drive wheels; a second motor provided on the power transmission path; a torque converter provided on the power transmission path between the first motor and the second motor; a first power control device; a second power control device; a motor radiator cooled by the fan and promoting the dissipation of heat from cooling water circulating between the first and second motors and the first and second power control devices; and a vehicle control device that, in motor driving mode, controls the second power control device to drive the hybrid vehicle with the second motor and controls the first power control device to rotate the fan via the engine.

Description

Technical Field

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[0001] The present invention relates to a hybrid vehicle.

Background Art

[0002] There is known a hybrid vehicle including an engine, a fan that rotates in conjunction with the engine, a motor, a power control device that controls power to the motor, and an engine radiator cooled by the fan (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In order to ensure the cooling performance of the motor and the power control device, a motor radiator may be provided in addition to the engine radiator. In this case, in the motor driving mode in which the engine is stopped and the vehicle is driven by the motor, the fan is also stopped. Therefore, there is a risk that the motor radiator cannot be sufficiently cooled, and the cooling of the motor and the power supply device may be insufficient. Further, when the power of the motor decreases in the motor driving mode, there is a risk that the driving performance decreases.

[0005] Therefore, an object of the present invention is to provide a hybrid vehicle that ensures the driving performance in the motor driving mode and the cooling performance of the motor and the power supply device.

Means for Solving the Problems

[0006] The above objective can be achieved by a hybrid vehicle comprising: an engine; a fan that rotates in conjunction with the engine; a first motor connected to the engine and provided on a power transmission path between the engine and the drive wheels; a second motor provided on the power transmission path; a torque converter provided on the power transmission path between the first motor and the second motor; a first power control device that controls the power to the first motor; a second power control device that controls the power to the second motor; a motor radiator that is cooled by the fan and promotes the dissipation of heat from the cooling water circulating between the first and second motors and the first and second power control devices; and a vehicle control device that, in a motor driving mode when combustion in the engine has stopped, controls the second power control device to drive the hybrid vehicle with the second motor and controls the first power control device to rotate the fan via the engine with the first motor.

[0007] The vehicle control device may, when there is a driving request in the motor driving mode and the requested driving force of the hybrid vehicle is below a threshold, control the second power control device to drive the hybrid vehicle using the second motor, and when there is a driving request in the motor driving mode and the requested driving force is above the threshold, control the first and second power control devices to drive the hybrid vehicle using the first and second motors.

[0008] The vehicle control device comprises an automatic transmission provided on the power transmission path between the torque converter and the second motor, and a first clutch provided on the automatic transmission. The vehicle control device may engage the first clutch when the vehicle is running in the motor driving mode, and when the vehicle is stopped in the motor driving mode, it may release the first clutch and control the second power control device to stop the second motor, and control the first power control device to rotate the fan via the engine using the first motor.

[0009] The vehicle control device is provided with a second clutch located on the power transmission path between the engine and the first motor, and may engage the second clutch in the motor driving mode. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a hybrid vehicle that ensures driving performance in motor-driven mode while also ensuring cooling performance for the motor and power supply device. [Brief explanation of the drawing]

[0011] [Figure 1] This is a schematic diagram of a hybrid vehicle. [Figure 2] This is a schematic diagram of the cooling system. [Figure 3] This is a flowchart illustrating motor-driven vehicle control. [Modes for carrying out the invention]

[0012] [Overall configuration of a hybrid vehicle] Figure 1 is a schematic diagram of the hybrid vehicle 1. The hybrid vehicle 1 is equipped with an engine 10, a first motor 15, and a second motor 22 as power sources for driving. The engine 10 is a gasoline engine with multiple cylinders, but it may also be a diesel engine or a hydrogen engine. The engine 10 is located on the front side of the hybrid vehicle 1. The hybrid vehicle 1 has rear wheels 31 and front wheels 32. Along the power transmission path from the engine 10 to the rear wheels 31, the following components are arranged in order from the engine 10 to the rear wheels 31: a clutch 14, a first motor 15, a torque converter 16, an automatic transmission 17, a sub-transmission 18, a transfer case 20, a rear propeller shaft 21, a second motor 22, a rear differential 23, and a rear drive shaft 24. Furthermore, along the power transmission path from the engine 10 to the front wheels 32, the following components are provided in order from the engine 10 toward the front wheels 32: K0 clutch 14, first motor 15, torque converter 16, automatic transmission 17, sub-transmission 18, transfer case 20, front propeller shaft 25, front differential 26, and front drive shaft 27.

[0013] The K0 clutch 14 is located on the power transmission path between the engine 10 and the first motor 15. The K0 clutch 14 engages when hydraulic pressure is supplied, connecting the power transmission between the engine 10 and the first motor 15. The K0 clutch 14 disengages when the hydraulic pressure supply is stopped, interrupting the power transmission between the engine 10 and the first motor 15. The K0 clutch 14 is an example of a second clutch.

[0014] The first motor 15 is connected to the battery 40 via a first PCU (Power Control Unit) 41. The second motor 22 is connected to the battery 40 via a second PCU 42. The battery 40 is a rechargeable secondary battery such as a nickel-metal hydride battery or a lithium-ion battery. The first motor 15 generates the driving force of the hybrid vehicle 1 in accordance with the power supplied from the battery 40 via the first PCU 41. The second motor 22 generates the driving force of the hybrid vehicle 1 in accordance with the power supplied from the battery 40 via the second PCU 42. The first motor 15 and the second motor 22 generate power to charge the battery 40 in accordance with the power transmitted from the engine 10, the rear wheels 31, and the front wheels 32. The power exchanged between the first motor 15 and the battery 40 is regulated by the first PCU 41. The power exchanged between the second motor 22 and the battery 40 is regulated by the second PCU 42. The first PCU 41 is an example of a first power control device. The second PCU 42 is an example of a second power control device.

[0015] The torque converter 16 is a fluid coupling with a torque amplification function. The torque converter 16 is installed on the power transmission path between the first motor 15 and the second motor 22. The torque converter 16 has a pump impeller, a turbine runner, and a stator. The pump impeller is connected to the output shaft of the first motor 15. The turbine runner is connected to the input shaft of the automatic transmission 17.

[0016] The automatic transmission 17 is a multi-stage transmission that switches the gear ratio in multiple stages. The automatic transmission 17 is located on the power transmission path between the torque converter 16 and the second motor 22. The automatic transmission 17 has an AT clutch 17c. The AT clutch 17c engages when hydraulic pressure is supplied, connecting the input shaft and output shaft of the automatic transmission 17. The AT clutch 17c disengages when the hydraulic pressure supply is stopped, disconnecting the input shaft and output shaft of the automatic transmission 17. When the AT clutch 17c is disengaged, the automatic transmission 17 enters a neutral state. The AT clutch 17c is an example of a first clutch.

[0017] The auxiliary transmission 18 can selectively set, for example, a gear stage with a large gear ratio between the output shaft of the automatic transmission 17 and the rear wheels 31 and a gear stage with a small gear ratio thereof.

[0018] The K0 clutch 14, the torque converter 16, the automatic transmission 17, and the auxiliary transmission 18 are supplied with hydraulic pressure from a hydraulic pump (not shown) via a hydraulic control mechanism 19. The hydraulic control mechanism 19 is provided with respective hydraulic circuits for the K0 clutch 14, the torque converter 16, the automatic transmission 17, and the auxiliary transmission 18, and various hydraulic control valves for controlling their operating hydraulic pressures.

[0019] The transfer 20 distributes the power of the engine 10, the first motor 15, and the second motor 22 to the rear wheels 31 and the front wheels 32. That is, the rear wheels 31 and the front wheels 32 are drive wheels.

[0020] A fan 12 is provided on the crankshaft 11 of the engine 10. The fan 12 rotates in conjunction with the crankshaft 11 of the engine 10. The engine radiator 51, the motor radiator 52, and the AC capacitor 53 are arranged so as to face the fan 12. When the fan 12 rotates, the engine radiator 51, the motor radiator 52, and the AC capacitor 53 are cooled. The engine radiator 51 promotes the heat radiation of the cooling water circulating through the engine 10. The motor radiator 52 promotes the heat radiation of the cooling water circulating through the first motor 15, the second motor 22, the first PCU 41, and the second PCU 42, which will be described in detail later. The AC capacitor 53 promotes the heat radiation of the refrigerant for air conditioning.

[0021] The hybrid vehicle 1 is provided with an ECU (Electronic Control Unit) 100 as a vehicle control device. The ECU 100 is an electronic control unit including an arithmetic processing circuit that performs various arithmetic processes related to the running control of the vehicle and a memory in which control programs and data are stored. The ECU 100 is an example of a vehicle control device.

[0022] The ECU 100 is connected to a group of sensors 60. The group of sensors 60 includes, for example, an ignition switch, a crank angle sensor, an air flow meter, a first motor rotation speed sensor, a second motor rotation speed sensor, an accelerator opening sensor, a shift position sensor, a vehicle speed sensor, a SOC (State Of Charge) sensor, and a driving mode switching switch. The ignition switch detects the on / off state of the ignition. The crank angle sensor detects the rotation speed of the crankshaft 11 of the engine 10. The air flow meter detects the intake air amount introduced into the engine 10. The first motor rotation speed sensor detects the rotation speed of the first motor 15. The second motor rotation speed sensor detects the rotation speed of the second motor 22. The accelerator opening sensor detects the accelerator opening, which is the opening of the accelerator pedal operated by the driver. The shift position sensor detects whether the position of the shift lever is in the P range position, R range position, N range position, or D range position. The vehicle speed sensor detects the traveling speed of the hybrid vehicle 1. The SOC sensor detects the charge amount of the battery 40. The driving mode switching switch is a switch capable of switching the driving mode described later.

[0023] The ECU 100 controls the driving of the engine 10, the first motor 15, and the second motor 22. Specifically, the ECU 100 controls the first PCU 41 to adjust the power supplied from the battery 40 to the first motor 15, thereby controlling the power of the first motor 15. The ECU 100 controls the second PCU 42 to adjust the power supplied from the battery 40 to the second motor 22, thereby controlling the power of the second motor 22. The ECU 100 controls the K0 clutch 14, the automatic transmission 17, and the sub-transmission 18 through the control of the hydraulic control mechanism 19.

[0024] The ECU 100 drives the hybrid vehicle 1 in either motor-only driving mode or hybrid driving mode. In motor-only driving mode, as will be described in more detail later, the combustion of the engine 10 is stopped, and the K0 clutch 14 engages to rotate the rear wheels 31 and front wheels 32 with the power of at least one of the first motor 15 and the second motor 22. In hybrid driving mode, the K0 clutch 14 engages to rotate the rear wheels 31 and front wheels 32 with the power of at least the engine 10. For example, when the required driving force for the hybrid vehicle 1 exceeds a predetermined value, the system switches from motor-only driving mode to hybrid driving mode. Also, when the charge level of the battery 40 falls below a predetermined value, the system switches from motor-only driving mode to hybrid driving mode. The driving mode can also be switched using a driving mode selector switch.

[0025] [Outline configuration of the cooling system] Figure 2 is a schematic diagram of the cooling system 2. The cooling system 2 is installed in the hybrid vehicle 1. The motor radiator 52, water pump 55, first motor 15, first PCU 41, second motor 22, and second PCU 42 are arranged along the path 4 through which the coolant flows. The water pump 55 is electrically powered and controlled by the ECU 100. When the water pump 55 is driven, the coolant circulates through path 4 to the motor radiator 52, first motor 15, first PCU 41, second motor 22, and second PCU 42. This cools the first motor 15, first PCU 41, second motor 22, and second PCU 42. The order in which the coolant flows is not limited to this. Also, the first motor 15, second motor 22, first PCU 41, and second PCU 42 may be connected in parallel or in series.

[0026] [Motor-driven control] Figure 3 is a flowchart illustrating motor driving control. This control is executed repeatedly while the ignition is on. The ECU 100 determines whether the driving mode is motor driving mode or not (step S1). This determination is made based, for example, on the requested driving force to the hybrid vehicle 1, the charge level of the battery 40, and the state of the driving mode selector switch. If the result in step S1 is No, this control terminates.

[0027] If the answer in step S1 is Yes, the ECU 100 determines whether or not there is a request to drive (step S2). This determination is made based on, for example, the position of the shift lever, the accelerator pedal position, and the vehicle speed. For example, if the position of the shift lever is in the D range position or R range position, and the accelerator pedal position indicates that the accelerator pedal is depressed, then step S2 is determined to be Yes. If the position of the shift lever is in the N range position or P range position, then step S2 is determined to be No.

[0028] If the answer in step S2 is Yes, the ECU 100 determines whether the requested driving force to the hybrid vehicle 1 is below a threshold (step S3). The threshold is set to the upper limit that allows both the rear wheels 31 and the front wheels 32 to be driven by the power of the second motor 22 alone. The requested driving force is determined based on the accelerator opening. If the accelerator opening is below a predetermined value, the answer in step S3 is Yes. If the accelerator opening is greater than the predetermined value, the answer in step S3 is No.

[0029] If the answer in step S3 is Yes, the ECU 100 engages the K0 clutch 14 and the AT clutch 17c, causing the hybrid vehicle 1 to move with the second motor 22 and the fan 12 to rotate via the engine 10 with the first motor 15 (step S4). Specifically, the ECU 100 controls the second PCU 42 to supply the second motor 22 with enough power to drive both the rear wheels 31 and the front wheels 32. Part of the power from the second motor 22 is transmitted to the rear wheels 31 via the rear differential 23 and the rear drive shaft 24, and the remainder of the power from the second motor 22 is transmitted to the front wheels 32 via the rear propeller shaft 21, the transfer case 20, the front propeller shaft 25, the front differential 26, and the front drive shaft 27. Furthermore, the ECU 100 controls the first PCU 41 to supply the first motor 15 with enough power to rotate the fan 12 via the crankshaft 11. In this case, the first motor 15 is not supplied with the power necessary to drive the rear wheels 31 or the front wheels 32.

[0030] If the answer in step S3 is No, the ECU 100 engages the K0 clutch 14 and the AT clutch 17c, and drives the hybrid vehicle 1 with the first motor 15 and the second motor 22, and rotates the fan 12 with the first motor 15 (step S5). Specifically, the ECU 100 controls the second PCU 42 to supply the second motor 22 with enough power to drive both the rear wheels 31 and the front wheels 32 with the second motor 22. Furthermore, the ECU 100 controls the first PCU 41 to supply the first motor 15 with enough power to rotate the fan 12 via the crankshaft 11 and drive both the rear wheels 31 and the front wheels 32 with the first motor 15.

[0031] Therefore, a portion of the power of the first motor 15 is transmitted to the fan 12 via the K0 clutch 14, and the remaining power of the first motor 15 is transmitted to the rear wheel 31 and the front wheel 32. Consequently, the power supplied to the first motor 15 in step S5 is greater than the power supplied to the first motor 15 in step S4. In other words, the power of the first motor 15 in step S5 is greater than the power of the first motor 15 in step S4.

[0032] If the answer in step S2 is No, the ECU 100 engages the K0 clutch 14 and releases the AT clutch 17c, stopping the second motor 22 while rotating the fan 12 with the first motor 15 (step S6). Specifically, the ECU 100 controls the second PCU 42 to stop the power supplied to the second motor 22. At this point, the AT clutch 17c is released. For example, if the first motor 15 is driven while the second motor 22 is stopped with the AT clutch 17c engaged, the pump impeller of the torque converter 16 rotates relative to the stopped turbine runner. This causes the torque converter 16 to heat up. By releasing the AT clutch 17c, the pump impeller and the turbine runner can rotate in the same direction, and the heat generated by the torque converter 16 as described above is suppressed.

[0033] As described above, in all cases of steps S4 to S6, the first motor 15 rotates the fan 12 via the engine 10. This promotes heat dissipation of the cooling water in the motor radiator 52, ensuring the cooling performance of the first motor 15, second motor 22, first PCU 41, and second PCU 42 in motor driving mode.

[0034] Furthermore, as in steps S4 and S5, the power of the first motor 15 and the second motor 22 necessary to drive the rear wheels 31 and front wheels 32 is controlled according to the required driving force. This ensures driving performance in motor-driven mode.

[0035] In the above embodiment, a sub-transmission 18, a transfer case 20, a front propeller shaft 25, and a front differential 26 were provided, but these may be omitted. That is, only the rear wheels 31 may be drive wheels, and the front wheels 32 may be driven wheels.

[0036] Although embodiments of the present invention have been described in detail above, the present invention is not limited to these specific embodiments, and various modifications and changes are possible within the scope of the gist of the present invention as described in the claims. [Explanation of symbols]

[0037] 1. Hybrid vehicle 2 Cooling System 10 Engines 11 Crankshaft 12 Fans 14 K0 Clutch (Second Clutch) 15 First Motor 16 Torque Converter 17 Automatic transmission 17c AT clutch (first clutch) 22 Second motor 40 batteries 41. First PCU (First Power Control Unit) 42. Second PCU (Second Power Control Unit) 52 Motor Radiator 100 ECU (Vehicle Control Unit)

Claims

1. It is a hybrid vehicle, The engine and A fan that rotates in conjunction with the aforementioned engine, A first motor connected to the engine and provided on the power transmission path between the engine and the drive wheels, A second motor is provided on the aforementioned power transmission path, A torque converter provided on the power transmission path between the first motor and the second motor, A first power control device for controlling power to the first motor, A second power control device for controlling power to the second motor, A motor radiator, which is cooled by the aforementioned fan and promotes the dissipation of heat from the cooling water circulating between the first and second motors and the first and second power control devices, In a motor-driven mode in which combustion in the engine has stopped, the vehicle control device controls the second power control device to drive the hybrid vehicle with the second motor, and controls the first power control device to rotate the fan via the engine with the first motor, A hybrid vehicle equipped with [a specific feature / ability].

2. The vehicle control device, when there is a driving request in the motor driving mode and the requested driving force of the hybrid vehicle is below a threshold, controls the second power control device to drive the hybrid vehicle with the second motor, and when there is a driving request in the motor driving mode and the requested driving force is above the threshold, controls the first and second power control devices to drive the hybrid vehicle with the first and second motors, the hybrid vehicle according to claim 1.

3. An automatic transmission provided on the power transmission path between the torque converter and the second motor, The automatic transmission is provided with a first clutch, The hybrid vehicle according to claim 2, wherein the vehicle control device engages the first clutch when the vehicle is running in the motor driving mode, and when the vehicle is stopped in the motor driving mode, it disengages the first clutch and controls the second power control device to stop the second motor, and controls the first power control device to rotate the fan via the engine using the first motor.

4. The system includes a second clutch provided on the power transmission path between the engine and the first motor, The hybrid vehicle according to claim 3, wherein the vehicle control device engages the second clutch in the motor driving mode.

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