Vehicle control device

Abstract

A vehicle control device of a hybrid vehicle that has an engine and an electric motor, a transfer drive axle that has a power transmission path that links the engine and the electric motor to a drive wheel, a temperature detection unit that detects a temperature of the transfer drive axle, and a control section that switches between a series operation mode in which the vehicle is driven by the electric motor using electric power generated by the rotation of the engine and a parallel operation mode in which the vehicle is driven by the engine and the electric motor, the vehicle control device performing first control that prioritizes driving in the parallel operation mode when the temperature of the transfer drive axle is at or above a first prescribed temperature.

Description

Technical Field

[0001] This invention relates to a vehicle control device for a hybrid electric vehicle. Background Technology

[0002] Hybrid vehicles, which use both an engine and an electric motor to drive the vehicle, are widely popular. Hybrid vehicles have an engine (internal combustion engine) and an electric motor (electric motor), and are configured such that the electric motor assists the engine in driving when the vehicle is in motion, and can regenerate electricity when decelerating.

[0003] Hybrid vehicles come in many forms. For example, a mild hybrid vehicle has the ability to operate solely on the engine depending on the vehicle's driving conditions, to perform regenerative braking, and to assist the engine's driving force with the electric motor's power. A strong hybrid vehicle, in addition to the above functions, also has the ability to operate solely on the electric motor. The transmission drive axle of such a hybrid vehicle includes a speed reducer for adjusting the torque and speed transmitted to the drive wheels, a clutch for switching driving states, and a clutch drive mechanism for actuating the clutch, among other devices. Furthermore, Patent Documents 1 and 2 disclose techniques for suppressing excessive temperature rise within this transmission drive axle.

[0004] Patent Document 1 describes a hybrid vehicle that includes two electric generators: a first electric generator and a second electric generator. It can select between a driving mode that drives both the first and second electric generators and a driving mode that drives only the second electric generator. A planetary gear mechanism is provided in the power transmission path from the engine and the first electric generator to the drive wheels.

[0005] Furthermore, in order to suppress the temperature rise of the planetary gear mechanism when driving both electric motors, a driving force sharing ratio for each electric generator is set for the required driving force. Specifically, when the temperature of the pinion gear in the planetary gear mechanism is higher than a specified temperature, the driving force sharing ratio of the first electric generator is set to be lower than when the temperature of the pinion gear is lower than the specified temperature. This suppresses the temperature rise of the pinion gear and prevents situations where the driving mode of both the first and second electric generators is restricted.

[0006] Furthermore, the hybrid vehicle described in Patent Document 2, in addition to an engine, also includes a first rotating machine and a second rotating machine as power sources. Further, it includes a first clutch and a second clutch in the power transmission path. A planetary gear mechanism is provided in the power transmission path from the engine and the first rotating machine to the drive wheels. The first clutch is disposed between this power transmission path and the second rotating machine. The second clutch is a one-way clutch disposed in parallel with the first clutch. The second rotating machine transmits power between itself and the power transmission path via at least one of the first clutch and the second clutch.

[0007] Furthermore, in the prescribed driving mode where the rotation of the second rotating mechanism stops and the vehicle moves forward, the first clutch is disengaged. By disengaging the first clutch and separating the second rotating mechanism from the power transmission path, the rotation of the second rotating mechanism due to the rotation of the power transmission path is suppressed, reducing resistance and mechanical losses in the second rotating mechanism, resulting in reduced engine output. Additionally, the control unit of this hybrid vehicle has the following function: when the oil temperature is low, it limits the operating range of the prescribed driving mode compared to when the oil temperature is high. Specifically, when the oil temperature is lower than the prescribed temperature, the prescribed driving mode is prohibited, and the oil is heated by the heat generated by the second rotating mechanism, achieving a premature rise in oil temperature.

[0008] Existing technical documents

[0009] Patent documents

[0010] Patent Document 1: Japanese Patent Application Publication No. 2017-149210

[0011] Patent Document 2: Japanese Patent Application Publication No. 2015-131512

[0012] The technical problem that the invention aims to solve

[0013] However, due to the increased weight, higher power output, and increased maximum engine speed of hybrid vehicles in recent years, the temperature of the transmission drive axle has tended to rise more than before. Furthermore, under prolonged operation in harsh, unusual operating conditions, the temperature of the transmission drive axle is expected to exceed expectations. If the temperature of the transmission drive axle exceeds the permissible temperature and this condition persists for an extended period, oil deterioration will be accelerated, leading to increased loads on gears and bearings, and accelerating the hardening of resin components such as oil seals, which is undesirable. Therefore, there is a need to minimize the temperature rise of the transmission drive axle.

[0014] Furthermore, especially in hybrid vehicles that have both series and parallel operation modes, there is a problem in how to use each operation mode separately in order to suppress the temperature rise of the transmission drive axle. In series operation mode, the engine is used to generate electricity, and the electric motor is used to drive the vehicle. In parallel operation mode, the electric motor assists in driving the engine during the most energy-consuming periods such as startup and acceleration.

[0015] In this respect, Patent Document 1 reduces the driving force sharing ratio of the first electric generator when the temperature of the pinion of the planetary gear mechanism is high, but it does not disclose how to separately use the series operation mode and the parallel operation mode for temperature management. Furthermore, Patent Document 1 aims to reduce the possibility of driving being restricted due to both the first and second electric generators; this technology does not contribute to suppressing the temperature rise of the transmission drive axle. Additionally, Patent Document 2 restricts the driving mode when the oil temperature is low compared to when the oil temperature is high; this technology also does not contribute to suppressing the temperature rise of the transmission drive axle. Summary of the Invention

[0016] Therefore, the technical problem of the present invention is to suppress the temperature rise of the transmission drive axle in a hybrid vehicle.

[0017] Technical means for solving technical problems

[0018] To solve the aforementioned technical problems, the present invention is a vehicle control device for a hybrid vehicle, the hybrid vehicle comprising: an engine and an electric motor; a transmission drive axle having a power transmission path connecting the engine and the electric motor to drive wheels; a temperature detection unit that detects the temperature of the transmission drive axle; and a control unit that switches between a series operation mode and a parallel operation mode. The series operation mode is a mode in which the vehicle travels by driving the electric motor using electricity generated by the rotation of the engine, and the parallel operation mode is a mode in which the vehicle travels by driving the vehicle using both the engine and the electric motor. In this vehicle control device, when the temperature of the transmission drive axle is above a first predetermined temperature, the control unit performs a first control that prioritizes travel in the parallel operation mode.

[0019] Here, the following structure can be adopted: a secondary battery is provided, which supplies power to the electric motor, and a second control is performed to switch to the series operation mode when the charge state of the secondary battery drops to less than a first predetermined value due to operation in the parallel operation mode after the first control.

[0020] Alternatively, the following structure can be adopted: when the charging state of the secondary battery is restored to a value above the second predetermined value due to driving in the series operation mode after the second control, a third control is performed to switch to the parallel operation mode, wherein the second predetermined value is set to a value higher than the first predetermined value.

[0021] Among these methods, the following structure can be adopted: when the temperature of the transmission drive axle reaches a second predetermined temperature or higher, a fourth control is performed to limit the drive torque, engine output, or engine speed, wherein the second predetermined temperature is set to a temperature higher than the first predetermined temperature.

[0022] Furthermore, the following structure can be adopted: the hybrid vehicle is a plug-in hybrid vehicle and has a power supply function that supplies power to the outside from the secondary battery.

[0023] The effects of the invention

[0024] In this invention, since driving in parallel operation mode is promoted when the temperature of the transmission drive axle is above a first predetermined temperature, the temperature rise of the transmission drive axle can be effectively suppressed. Attached Figure Description

[0025] Figure 1 This is a schematic diagram illustrating a vehicle according to one embodiment of the present invention.

[0026] Figure 2 This is a diagram illustrating an example of control.

[0027] Figure 3 This is a flowchart illustrating an example of control.

[0028] Figure 4 This is a flowchart illustrating an example of control.

[0029] Figure 5 This is a flowchart illustrating an example of control. Detailed Implementation

[0030] Embodiments of the present invention will be described with reference to the accompanying drawings. Figure 1 As shown, the vehicle 10 equipped with the vehicle control device according to the present invention is a strong hybrid vehicle that uses an engine (internal combustion engine) 6 and an electric motor (electric motor) 4 as drive sources. In this embodiment, the vehicle 10 is configured as a plug-in hybrid vehicle with the front wheels as drive wheels 8.

[0031] Vehicle 10 is equipped with a power transmission system (power transmission path) 7 that connects the front wheels (drive wheels 8) to the engine 6 and the electric motor 4 respectively. Power transmission path 7 includes: a clutch 3 for switching drive states; a hydraulic pump 2 for driving the clutch 3; and a speed reducer for regulating the torque and speed transmitted to the drive wheels 8, etc., forming a variable speed drive axle 1. The driving force of the engine 6 and the electric motor 4 is transmitted to the drive wheels 8 via the variable speed drive axle 1, thereby moving vehicle 10. Additionally, vehicle 10 is equipped with a generator 5.

[0032] Engine 6 can be a gasoline engine that uses gasoline as fuel or a diesel engine that uses light oil as fuel. Through the combustion of fuel, crankshaft 6a rotates, and this rotation is transmitted to input shaft 11.

[0033] The motor 4 includes a rotor 4b that rotates integrally with the rotating shaft 4a and a stator 4c fixed to the outer periphery of the rotor 4b within a housing. The rotating shaft 4a and rotor 4b rotate together using electricity stored in the battery 30. The battery 30 can be, for example, a lithium-ion battery or a nickel-metal hydride battery, or a secondary battery. Hereinafter, the battery 30 will be referred to as the secondary battery 30. An inverter is provided with the battery 4 to convert the direct current supplied from the secondary battery 30 into alternating current. By controlling the inverter, the speed of the motor 4 can be adjusted.

[0034] Generator 5 is an electric motor that functions as a starter for engine 6, and is also a generator that produces electricity through the rotation of engine 6 and drive wheel 8; it is also called an electric generator. Generator 5 includes a rotor 5b that rotates integrally with rotating shaft 5a and a stator 5c fixed to the outer periphery of rotor 5b in a housing. The electricity generated by generator 5 charges secondary battery 30 (drive battery), which serves as the power supply source for motor 4, and is also supplied directly to motor 4 depending on operating conditions. In addition, starting engine 6 by generator 5 is achieved by electricity supplied from secondary battery 30 (low-voltage battery).

[0035] The transmission drive axle 1 functions as a power transmission path between the engine 6, the electric motor 4, and the drive shaft 9 connected to the drive wheels 8, which serve as the drive source. Additionally, the transmission drive axle 1 includes, midway through this power transmission path, a gearbox (reduction gear, not shown) and a final drive unit (final reduction gear) including a differential device 16 with a differential gear 16a. Figure 1 As shown, in this embodiment, three power transmission paths, namely the first path 31, the second path 32, and the third path 33, are set inside the transmission drive axle 1.

[0036] The first path 31 (first power transmission mechanism) connects the crankshaft 6a of the engine 6 to the drive shaft 9. A clutch 3 for engaging and disengaging power transmission is disposed at any point along the first path 31. For example, a multi-plate clutch can be used as the clutch 3. Inside the clutch 3 are a drive-side engaging element 3a for receiving driving force from the engine 6 and a driven-side engaging element 3b for outputting driving force to the drive wheel 8. The approach (engagement) and disengagement (disengagement) of the drive-side engaging element 3a and the driven-side engaging element 3b are controlled by hydraulic pressure supplied from the pump 2.

[0037] The second path 32 (second power transmission mechanism) connects the rotating shaft 4a of the motor 4 to the drive shaft 9. The motor 4 can assist the driving force of the engine 6, or it can drive the vehicle 10 solely using the driving force of the motor 4, depending on the operating state. For example, when the vehicle 10 starts or travels at low speed, it can be set to an electric operation mode (series operation mode) where the vehicle 10 travels solely using the driving force of the motor 4, without relying on the driving force of the engine 6. Furthermore, when the vehicle 10's speed reaches or exceeds a predetermined speed, depending on the operating state, it can be set to an auxiliary operation mode (parallel operation mode) where the driving force of the motor 4 is added to the driving force of the engine 6, or an engine operation mode where the driving force of the motor 4 stops and the vehicle travels solely using the driving force of the engine 6.

[0038] The third path 33 (third power transmission path) connects the crankshaft 6a of the engine 6 to the rotating shaft 5a of the generator 5. Rotation from the drive wheel 8 side or from the engine 6 side is input to the generator 5 via the third path 33, and electricity is generated through this input rotation. Hereinafter, the rotating shaft connected to the crankshaft 6a in the transmission drive axle 1 is referred to as the input shaft 11. In addition, the rotating shafts in the transmission drive axle 1 that are respectively connected to the drive shaft 9, the rotating shaft 4a of the motor 4, and the rotating shaft 5a of the generator 5 are referred to as the output shaft 12, the motor shaft 13, and the generator shaft 14. Furthermore, the rotating center shaft of the clutch 3 disposed in the transmission drive axle 1 is referred to as the clutch shaft 15, the rotating center shaft of the pump 2 is referred to as the pump shaft 2b, and the secondary shaft disposed parallel to the output shaft 12 is referred to as the secondary shaft 17.

[0039] like Figure 1As shown, a first gear 11a and a second gear 11b are arranged side-by-side axially on the input shaft 11. The first gear 11a meshes with a third gear 14a fixed to the generator shaft 14 and transmits power to the generator shaft 14. The second gear 11b meshes with a fourth gear 15a connected to the drive-side engagement element 3a of the clutch 3. The driven-side engagement element 3b, which is opposite to the drive-side engagement element 3a, is fixed to the clutch shaft 15. A fifth gear 15b is also provided on the clutch shaft 15 to transmit driving force to the output shaft 12. The fifth gear 15b meshes with a differential gear 16a fixed to the output shaft 12.

[0040] A pump shaft 2b is connected to one end of the clutch shaft 15. The pump shaft 2b is connected to a drive body 2a built into the pump 2. In this embodiment, the pump 2 is a vane pump, and the drive body 2a is equivalent to a rotor. The pump 2 is not limited to this embodiment; a piston pump or a gear pump can also be used. The drive body 2a generates hydraulic pressure using the driving force (rotation of the drive wheel 8) transmitted from the clutch shaft 15 side and pumps working oil into the hydraulic circuit. The hydraulic pressure is transmitted to the clutch 3 and is used as the pressure to bring the drive-side engagement element 3a and the driven-side engagement element 3b close to each other and engage. That is, when the vehicle speed of 10 reaches a predetermined speed or higher, the hydraulic pressure generated by the pump 2 rises to a level sufficient to engage the drive-side engagement element 3a and the driven-side engagement element 3b, and the clutch 3 is engaged. When the clutch 3 is engaged, the driving force of the engine 6 is transmitted to the drive wheel 8 via the first path 31. At this time, if the engine 6 is not running, the engine 6 is started appropriately. If the vehicle 10 is traveling at a speed less than the specified speed, the control is achieved by disengaging the clutch 3 and stopping the engine 6.

[0041] A sixth gear 13a is provided on the motor shaft 13, and a seventh gear 17a and an eighth gear 17b are arranged side by side axially on the countershaft 17. The sixth gear 13a meshes with the seventh gear 17a on the countershaft 17, and the eighth gear 17b meshes with the differential gear 16a fixed to the output shaft 12. Therefore, the driving force of the motor 4 is transmitted to the drive wheel 8 via the second path 32.

[0042] Furthermore, the engine 6, clutch 3, motor 4, generator 5, and other components are controlled by a control unit 21 equipped with an electronic control unit 20 mounted on the vehicle 10. The electronic control unit 20 includes a state of charge detection unit 22, which calculates the state of charge of the secondary battery 30 based on factors such as the battery pack voltage; that is, the ratio of the remaining capacity of the secondary battery 30 to the total capacity of the secondary battery 30 capable of storing electricity (remaining capacity / total capacity). Hereinafter, in particular, the state of charge of the drive battery among the multiple secondary batteries 30 will be referred to as the state of charge (SOC).

[0043] The vehicle 10 is equipped with a temperature detection unit 34 for detecting the temperature of the transmission drive axle 1. In this embodiment, a temperature sensor is used as the temperature detection unit 34 to detect the temperature of the working oil or lubricating oil inside the transmission drive axle 1, and the detected temperature is taken as the temperature of the transmission drive axle 1. Hereinafter, the temperature of the transmission drive axle 1 detected by the temperature detection unit 34 will be referred to as the T / A temperature.

[0044] The control unit 21 of the electronic control unit 20 controls the switching between series operation mode and parallel operation mode. In series operation mode, the motor 4 is driven by electricity generated from the rotation of the engine 6. In parallel operation mode, the vehicle travels using both the engine 6 and the motor 4. Additionally, in cases where the state of charge (SOC) is lower than a specified value, an engine operation mode is selected where the vehicle travels using only the engine 6. In series operation mode, the driving force is transmitted from the motor 4 to the drive wheel 8 via the second path 32. In parallel operation mode, the driving force is transmitted from the engine 6 to the drive wheel 8 via the first path 31, and also from the motor 4 to the drive wheel 8 via the second path 32.

[0045] The temperature information (T / A) detected by the temperature detection unit 34 is sent to the temperature information receiving unit 23 of the electronic control unit 20. When the temperature of the transmission drive axle 1 is above a first predetermined temperature T1, the control unit 21 performs a first control that prioritizes driving in parallel operation mode. In the first control, for example... Figure 2 As shown by symbol a in graph A, when the temperature T / A ( Figure 2 When the oil temperature (represented in [°C] in Chart A) reaches or exceeds the first predetermined temperature T1 (in this embodiment, T1 = 125°C), control is applied to switch to parallel operation mode even if the vehicle is traveling in series operation mode at that time. If the vehicle is traveling in parallel operation mode at that time, control is applied to continue operating in parallel mode. That is, in the first control, parallel operation mode is promoted (preferred). Furthermore, Figure 2The horizontal axis of each chart represents time, and they correspond one-to-one.

[0046] Figure 3 This describes the flow of the first control step. Control begins in step s11, and the vehicle speed is determined in step s12. If the vehicle speed is above the specified speed (yes in s12), the process proceeds to step s13. If the vehicle speed is below the specified speed (no in s12), since the T / A temperature will not rise excessively and is outside the range of this control, the process moves to step s30 and ends control. Next, the required output (required torque) is determined in step s13. If the required output is above the specified output (yes in s13), the process proceeds to step s14. If the required output is below the specified output (no in s13), since the T / A temperature will not rise excessively and is outside the range of this control, the process also ends control. In step s14, the operating mode is determined. If the operating mode is a series operating mode (yes in s14), the process proceeds to step s15. If the operating mode is not a series operating mode (no in s14), the process also ends control. In step s15, the T / A temperature is determined. If the T / A temperature is less than the first specified temperature T1 (if s15 is yes), proceed to step s16 to continue the series operation mode and return to step s12. If the T / A temperature is greater than the first specified temperature T1 (if s15 is no), proceed to step s17 and switch to parallel operation mode.

[0047] By switching to parallel operation mode, the load on motor 4 is reduced and the T / A temperature decreases. This is because, compared to driving in series operation mode, in parallel operation mode, the output of motor 4, the speed of engine 6 are reduced, and the speed difference in clutch 3 is also reduced, thus making it difficult for the T / A temperature to rise. Therefore, the temperature rise of the transmission drive axle 1 can be suppressed without sacrificing the vehicle speed and drive torque (see reference). Figure 2 The operation continues as shown in charts B and E. That is, in the first control, when the T / A temperature is above a first predetermined temperature, operation in parallel mode is promoted, and the rise in T / A temperature is suppressed. Furthermore, although the power generation output and engine speed change (refer to...) Figure 2 Charts F and G <1> (This is due to the shift to parallel operation mode and does not affect vehicle speed or drive torque.)

[0048] When driving continues in parallel operation mode after the first control is performed, the SOC (State of Charge) of the secondary battery 30 is used as an indicator of its state of charge. Figure 2 The remaining charge (represented as [%] in Chart C) gradually decreases. Figure 2In diagram C, a downward-sloping arrow pointing towards point b indicates a decrease in State of Charge (SOC). When the SOC drops below a preset first predetermined value S1, a second control operation switches to series operation mode. That is, when the SOC falls below the first predetermined value S1 due to operation in parallel mode, parallel operation mode is disabled and the system switches to series operation mode. The first predetermined value S1 can be set to values ​​such as 10%, 20%, or 30% depending on the vehicle type and operating conditions. Furthermore, similarly, although the power generation output and engine speed change (see reference...) Figure 2 Charts F and G <2> (This is due to the shift to series operation mode and does not affect vehicle speed or drive torque.)

[0049] Then, when driving in series operation mode after the second control is performed, the SOC of the secondary battery 30 is restored. Figure 2 In diagram C, an upward-sloping arrow pointing to the right towards point c indicates a rise in SOC. Then, when the SOC recovers to a second predetermined value S2, which is set to be higher than the first predetermined value S1, a third control is initiated to switch to parallel operation mode in order to restart control that lowers the T / A temperature. That is, when the SOC is above the second predetermined value S2 due to operation in series mode, series operation mode is disabled and the system switches to parallel operation mode. Upon switching to parallel operation mode, the T / A temperature subsequently decreases. Figure 2 In chart C, a downward-sloping arrow pointing towards point d indicates a decrease in SOC. Furthermore, the second specified value S2 can be set to values ​​such as 70%, 80%, or 90% depending on the vehicle type and operating conditions. Similarly, although the power generation output and engine speed change (refer to...) Figure 2 Charts F and G <3> (This is due to the shift to parallel operation mode and does not affect vehicle speed or drive torque.)

[0050] Subsequently, depending on the SOC status, the second and third controls are repeated alternately. Here, as... Figure 2 As shown in graph S, the T / A temperature gradually increases. This is because the increase in T / A temperature in the series operation mode exceeds the decrease in T / A temperature in the parallel operation mode, thus resulting in an overall increase in T / A temperature. Figure 2 In Chart A, the upward-sloping arrow pointing towards location e indicates the rise in temperature at T / A.

[0051] Figure 4This describes the flow of the second and third controls. After transitioning to parallel operation mode in the first control, the State of Charge (SOC) is determined in step s18. If the SOC is greater than or equal to the first predetermined value S1 (yes in s18), the process proceeds to step s19 and continues in parallel operation mode, then returns to step s18. If the SOC is less than the first predetermined value S1 (no in s18), the process proceeds to step s20 and transitions to series operation mode. Next, the SOC is determined again in step s21. If the SOC is greater than or equal to the second predetermined value S2 (yes in s21), the process proceeds to step s22, transitions to parallel operation mode, and returns to step s18. If the SOC is less than the second predetermined value S2 (no in s21), the process proceeds to step s23 and continues in series operation mode.

[0052] During the alternating repetition of the second and third controls, subsequently, when the T / A temperature becomes a second predetermined temperature T2, which is set to be higher than the first predetermined temperature T1, a fourth control (output limiting control) is performed in series operation mode to limit the drive torque of the motor 4, the output of the engine 6, or the speed of the engine 6. That is, in the fourth control, for example... Figure 2 As indicated by symbol e in diagram A, when the T / A temperature reaches or exceeds the second predetermined temperature T2 (in this embodiment, T2 = 140°C), control is implemented in series operation mode to reduce the T / A temperature by limiting one or more, or all of, the drive torque of the motor 4, the output of the engine 6, and the speed of the engine 6 to below the predetermined upper limit. Here, the drive torque of the motor 4 refers to the torque actually commanded and executed by the electronic control unit 20 relative to the required torque input based on the driver's throttle input. By performing this fourth control, the burden on the transmission drive axle 1 can be reduced, and the T / A temperature can be lowered. Furthermore, when the control limiting the output and speed of the engine 6 is performed as the fourth control, upper and lower limits are set for the output and speed of the engine 6, limiting it to continue operating within a range above the lower limit and below the upper limit. If the T / A temperature falls below the first predetermined temperature T1, these fourth controls are released, and the normal operation mode is restored.

[0053] Figure 5This describes the flow of the fourth control. During the continuation of the series operation mode after the third control, the T / A temperature is determined in step s24. If the T / A temperature is above the second specified temperature T2 (s24 is yes), the process proceeds to step s25 for output limiting control. Alternatively, if the T / A temperature is below the second specified temperature T2 (s24 is no), the process proceeds to step s27. If the T / A temperature further falls below the first specified temperature T1 (s27 is no), the necessity for temperature reduction decreases, so the process proceeds to step S30 and control ends. Furthermore, if the T / A temperature is above the first specified temperature T1 in step s27 (s27 is yes), the process proceeds to step s28 and continues the series operation mode. If, in step s29, the T / A temperature becomes above the second specified temperature T2 (s29 is yes), the process proceeds to step s25 for output limiting control. Through the output limiting control in step s25, if the T / A temperature is below the first specified temperature T1 (s26 is yes), the process proceeds to step S30 and control ends. In addition, if the T / A temperature is above the first specified temperature T1 (no in s26), then return to step s25 and continue to output the limit control.

[0054] In the above embodiment, although a temperature sensor is used as the temperature detection unit 34 to detect the temperature of the working oil or lubricating oil inside the transmission drive axle 1, the temperature detection unit 34 can also use other means, as long as it can detect the temperature inside the transmission drive axle 1. For example, a sensor that detects the temperature of components such as gears inside the transmission drive axle 1 can also be used.

[0055] Furthermore, although the vehicle 10 is configured as a front-wheel-drive (FF) hybrid vehicle in the above embodiment, it can also be configured as a rear-wheel-drive (FR) vehicle or a 4WD vehicle with both front and rear wheels as drive wheels. Additionally, although the vehicle 10 is configured as a plug-in hybrid vehicle in the above embodiment and has a power supply function that allows it to supply power to external sources from the secondary battery 30, the vehicle 10 is not limited to a plug-in hybrid vehicle and can also be a hybrid vehicle constructed in other forms.

[0056] While various embodiments have been described above with reference to the accompanying drawings, it is self-evident that the present invention is not limited to these examples. Various modifications and alterations will be readily apparent to those skilled in the art within the scope of the claims, and these should also be understood to fall within the technical scope of the present invention. Furthermore, the structural elements in the above embodiments can be combined arbitrarily without departing from the spirit of the invention.

[0057] Furthermore, this application is based on Japanese Patent Application No. 2021-095806 filed on June 8, 2021, and its contents are incorporated herein by reference.

[0058] Symbol Explanation

[0059] 1. Variable speed drive axle

[0060] 2 pumps

[0061] 3. Clutch

[0062] 4. Motors (electric motors)

[0063] 5. Generator

[0064] 6 engines

[0065] 8 drive wheels

[0066] 21 Control Department

[0067] 30 Secondary batteries

Claims

1. A vehicle control device, specifically for a hybrid vehicle, the hybrid vehicle comprising: Engine and electric motor; A variable speed drive axle, the variable speed drive axle having a first power transmission path connecting the engine to the drive wheel and a second power transmission path connecting the electric motor to the drive wheel; A temperature detection unit that detects the temperature of the transmission drive axle; as well as The control unit switches between a series operation mode and a parallel operation mode. In the series operation mode, the driving force generated by the electric motor driven by the rotation of the engine is transmitted to the drive wheels via a second power transmission path. In the parallel operation mode, the driving forces generated by the engine and the electric motor are transmitted to the drive wheels via a first power transmission path and a second power transmission path, respectively. The control unit is characterized in that... In this vehicle control device, When the temperature of the transmission drive axle, which changes due to the operation of the first power transmission path and the second power transmission path, is above a first predetermined temperature, the control unit performs a first control to prioritize driving in the parallel operation mode. In the first control, when the temperature of the transmission drive axle is above the first predetermined temperature... When the vehicle is driven in the series operation mode until the temperature of the transmission drive axle exceeds the first specified temperature, it switches to the parallel operation mode. When the temperature of the transmission drive axle reaches above the first specified temperature during operation in the parallel operation mode, the parallel operation mode continues.

2. The vehicle control device according to claim 1, characterized in that, It is equipped with a secondary battery that supplies power to the electric motor. If the charge state of the secondary battery drops below a first predetermined value due to operation in the parallel operation mode after the first control, a second control is performed to switch to the series operation mode.

3. The vehicle control device according to claim 2, characterized in that, If the charging state of the secondary battery is restored to above the second predetermined value due to driving in the series operation mode after the second control, a third control is performed to switch to the parallel operation mode, and the second predetermined value is set to a value higher than the first predetermined value.

4. The vehicle control device according to claim 2, characterized in that, The hybrid vehicle is a plug-in hybrid vehicle and has a power supply function that supplies power to the outside from the secondary battery.

5. The vehicle control device according to claim 3, characterized in that, The hybrid vehicle is a plug-in hybrid vehicle and has a power supply function that supplies power to the outside from the secondary battery.

6. The vehicle control device according to claim 1, characterized in that, When the temperature of the transmission drive axle reaches or exceeds a second predetermined temperature, a fourth control is performed to limit the drive torque, engine output, or engine speed. The second predetermined temperature is set to a temperature higher than the first predetermined temperature.

7. The vehicle control device according to claim 2, characterized in that, When the temperature of the transmission drive axle reaches or exceeds a second predetermined temperature, a fourth control is performed to limit the drive torque, engine output, or engine speed. The second predetermined temperature is set to a temperature higher than the first predetermined temperature.

8. The vehicle control device according to claim 3, characterized in that, When the temperature of the transmission drive axle reaches or exceeds a second predetermined temperature, a fourth control is performed to limit the drive torque, engine output, or engine speed. The second predetermined temperature is set to a temperature higher than the first predetermined temperature.

9. The vehicle control device according to claim 4, characterized in that, When the temperature of the transmission drive axle reaches or exceeds a second predetermined temperature, a fourth control is performed to limit the drive torque, engine output, or engine speed. The second predetermined temperature is set to a temperature higher than the first predetermined temperature.

10. The vehicle control device according to claim 5, characterized in that, When the temperature of the transmission drive axle reaches or exceeds a second predetermined temperature, a fourth control is performed to limit the drive torque, engine output, or engine speed. The second predetermined temperature is set to a temperature higher than the first predetermined temperature.

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