Control system for hybrid vehicles

Abstract

To provide a control device of a hybrid vehicle that enables engine start during manual driving with excellent responsibility and facilitates accurate control of driving torque and rotational speed of a pair of drive wheels during automatic driving.SOLUTION: In a hybrid vehicle 10 comprising an engine 12 and an electric motor MG as driving power sources, and a torque converter 20 with a lock-up clutch LU arranged in a power transmission path PT between the electric motor MG and a pair of drive wheels 14, an electronic control device 100 is configured such that: (a) it allows switching between automatic driving and manual driving; (b) during BEV driving and manual driving, it controls engagement and disengagement of the lock-up clutch LU in accordance with predetermined engagement and disengagement conditions; and (c) during BEV driving and automatic driving, it maintains the lock-up clutch LU in the engaged state.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a control device for a hybrid vehicle including an engine and an electric motor that serve as power sources for traveling, and a torque converter with a lock-up clutch provided in a power transmission path between the electric motor and a pair of drive wheels. [Background Art]

[0002] A control device for a hybrid vehicle including an engine and an electric motor that serve as power sources for traveling, and a torque converter with a lock-up clutch provided in a power transmission path between the electric motor and a pair of drive wheels, is known in the art. For example, the one described in Patent Document 1 is such a control device. The hybrid vehicle described in Patent Document 1 is capable of automatic driving that does not require acceleration and deceleration operations by a driver, and manual driving that follows acceleration and deceleration operations performed by the driver. [Prior Art Documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Unexamined Patent Publication No. 2023-93212 [Summary of the Invention] [Problem to be Solved by the Invention]

[0004] Patent Document 1 describes that the control states of a lock-up clutch include a released state, a slipped state, and an engaged state (which means a fully engaged state excluding the slipped state), but does not describe how the engagement and disengagement of the lock-up clutch is controlled during traveling in manual driving and during traveling in automatic driving. Generally, connection / disengagement control of a lock-up clutch is performed in accordance with a predetermined predetermined connection / disengagement condition.

[0005] During BEV operation, where the power source is solely the electric motor, when the lock-up clutch is released according to predetermined engagement / disengagement conditions, power transmission within the torque converter occurs via a fluid. In this mode, even if the required drive torque increases, for example, the engine can be started responsively while suppressing shocks generated in the power transmission path. However, because the drive torque and rotational speed transmitted to the pair of drive wheels fluctuate depending on the performance characteristics of the torque converter, it becomes difficult to accurately control the drive torque and rotational speed of the pair of drive wheels.

[0006] During BEV operation, where the power source is solely the electric motor, when the lock-up clutch is engaged according to predetermined engagement and disengagement conditions, power transmission within the torque converter occurs in a manner in which the pump impeller and turbine impeller are directly connected without the use of fluid. In this configuration, the driving torque and rotational speed transmitted to the pair of drive wheels do not fluctuate due to the performance characteristics of the torque converter, making it easy to precisely control the driving torque and rotational speed of the pair of drive wheels. However, if, for example, the required driving torque increases and the engine is started with high responsiveness, there is a risk that the shock generated in the power transmission path will become larger.

[0007] The present invention was made against the above circumstances, and its objective is to provide a control device for a hybrid vehicle that enables responsive engine starting during manual driving and facilitates accurate control of the driving torque and rotational speed of a pair of drive wheels during autonomous driving. [Means for solving the problem]

[0008] The gist of the present invention is a control device for a hybrid vehicle comprising an engine and an electric motor as power sources for driving, and a torque converter with a lock-up clutch provided in the power transmission path between the electric motor and a pair of drive wheels, wherein (a) it is possible to switch between automatic driving and manual driving, (b) when driving as a BEV with only the electric motor as the power source and when driving in manual mode, it controls the engagement and disengagement of the lock-up clutch according to predetermined engagement and disengagement conditions, and (c) when driving as a BEV and when driving in automatic mode, it keeps the lock-up clutch engaged. [Effects of the Invention]

[0009] According to the control device for a hybrid vehicle of the present invention, (a) automatic driving and manual driving are switchable, (b) during BEV driving where the power source is only the electric motor and during manual driving, the lock-up clutch is controlled to engage and disengage according to predetermined disengagement conditions, and (c) during BEV driving and during automatic driving, the lock-up clutch is engaged. This makes it possible to start the engine quickly during manual driving and to accurately control the driving torque and rotational speed of the pair of drive wheels during automatic driving. [Brief explanation of the drawing]

[0010] [Figure 1] This diagram shows a schematic configuration of a hybrid vehicle equipped with an electronic control device according to an embodiment of the present invention, as well as a functional block diagram representing the main parts of the control functions for various controls in the hybrid vehicle. [Figure 2] Figure 1 is a schematic diagram of the hydraulic system that controls the operation of the clutch K0, torque converter, and automatic transmission. [Figure 3] This is an example of a lock-up switching map, which is predetermined for the engagement and disengagement conditions of the lock-up clutch. [Figure 4] Figure 1 shows an example of a flowchart illustrating the control operation of the electronic control unit. [Modes for carrying out the invention]

[0011] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that in the embodiments, the drawings have been simplified or modified as appropriate, and the dimensional ratios and shapes of each part are not necessarily depicted accurately. [Examples]

[0012] Figure 1 is a schematic diagram of a hybrid vehicle 10 (hereinafter simply referred to as "vehicle 10") equipped with an electronic control device 100 according to an embodiment of the present invention, and is also a functional block diagram showing the main parts of the control functions for various controls in vehicle 10.

[0013] Vehicle 10 comprises an engine 12 and an electric motor MG, which are power sources for driving, and a power transmission device 16 provided in the power transmission path PT between the electric motor MG and a pair of drive wheels 14. Vehicle 10 is a hybrid vehicle. Vehicle 10 also comprises a hydraulic control circuit 40, an inverter 42, a battery 44, a starter motor 46, and an electronic control device 100.

[0014] The engine 12 is a well-known internal combustion engine. The electric motor MG is a so-called motor generator that has the function of an electric motor that generates mechanical power from electrical energy (electric motor function) and a generator that generates electrical energy from mechanical power (generator function). The battery 44 exchanges power with the electric motor MG via the inverter 42. The electric motor MG is rotationally driven by the power stored in the battery 44 and outputs power for driving the vehicle 10. In this specification, unless otherwise specified, torque, driving force, power, and force (power) are synonymous. The electric motor MG also generates power from the driving power input from the engine 12 via the clutch K0, or by converting the driven force input from the pair of drive wheels 14 into electricity through regeneration. The generated electricity is charged to the battery 44 via the inverter 42.

[0015] The power transmission device 16, housed in a case 18 which is a non-rotating member attached to the vehicle body, comprises, in order from the engine 12 side, an engine connecting shaft 28, a clutch K0, an electric motor connecting shaft 30, a torque converter 20, an input shaft 32 which is the input rotating member of the automatic transmission 22, and the automatic transmission 22, etc., and these are well-known components. The power transmission device 16 also comprises an output shaft 34 which is the output rotating member of the automatic transmission 22, a propeller shaft 36, a differential 24, and a pair of axles 38, etc., and these are well-known components. The clutch K0 is an engagement device that can disconnect and reconnect power transmission between the engine 12 and the electric motor MG, and is, for example, a wet multi-plate type hydraulic friction engagement device.

[0016] The torque converter 20 is a well-known torque converter. The torque converter 20 comprises a pump impeller 20a connected to the motor coupling shaft 30, a turbine impeller 20b connected to the input shaft 32, and a lock-up clutch LU that directly connects the pump impeller 20a and the turbine impeller 20b. The torque converter 20 is a fluid-type transmission device that can transmit power input from a power source for driving (engine 12, electric motor MG) to the input shaft 32 via fluid. The vehicle 10 is equipped with, for example, a mechanical oil pump 26 connected to the pump impeller 20a. The oil pump 26 is rotationally driven by a power source for driving (engine 12, electric motor MG) to discharge hydraulic oil.

[0017] The starter motor 46 is a motor for starting the engine 12, and is a well-known motor that can crank the engine 12 by meshing with a ring gear engraved on the outer circumference of a flywheel, for example.

[0018] The hydraulic control circuit 40 uses the hydraulic pressure of the hydraulic oil discharged from, for example, a mechanical oil pump 26 connected to the pump impeller 20a as the base pressure to supply the necessary hydraulic oil to each part of the case 18.

[0019] In the vehicle 10, either a BEV travel mode or an engine travel mode can be selected. The BEV travel mode is a travel mode in which the operation of the engine 12 is stopped and BEV (Battery Electric Vehicle) travel is performed using only the electric motor MG as a power source for traveling. The engine travel mode is a travel mode in which engine travel is performed using at least the engine 12 as a power source for traveling. In BEV travel, the clutch K0 is in a released state, and in engine travel, the clutch K0 is in an engaged state.

[0020] Figure 2 is a schematic configuration diagram of a hydraulic system 50 that controls operations related to the clutch K0, the torque converter 20, and the automatic transmission 22 shown in Figure 1.

[0021] In addition to an oil pump 26 and a hydraulic control circuit 40, the hydraulic system 50 includes an oil pan 52 provided at a lower portion of a case 18, and an oil cooler 54 that warms the hydraulic oil OIL when the temperature is low and cools the hydraulic oil OIL after warm-up is completed. The oil pump 26 is rotationally driven by the engine 12 and / or the electric motor MG to generate an original pressure of the hydraulic oil OIL supplied to the hydraulic control circuit 40. The oil pump 26 sucks up the hydraulic oil OIL that has refluxed to the oil pan 52 from a suction port 56 and discharges it to a discharge oil passage 58. The discharge oil passage 58 is connected to an oil passage in the hydraulic control circuit 40 (for example, a line pressure oil passage 60 through which a line pressure PL [Pa] circulates).

[0022] The hydraulic control circuit 40 includes a primary regulator valve 62 that regulates the line pressure PL using the hydraulic pressure output (generated) from the oil pump 26 as an original pressure, an AT / LU hydraulic control system 64 that controls the shifting operation of the automatic transmission 22 and the connection / disconnection state (=connected state and disconnected state) of the clutch K0 using the line pressure PL as an original pressure, and a K0 hydraulic control system 66 that controls the connection / disconnection state of the clutch K0 using the line pressure PL as an original pressure.

[0023] The AT / LU hydraulic control system 64 includes multiple solenoid valves 68 that regulate the pressure of the hydraulic oil supplied to the hydraulic actuators in the automatic transmission 22, control the hydraulic oil supplied to the lock-up clutch LU, switch the oil passages through which the hydraulic oil flows, open the oil passages, and close the oil passages. These oil passages include, for example, an oil passage 70 connected to the hydraulic actuators in the automatic transmission 22, an oil passage 72 connected to the lock-up clutch LU, lubrication oil passages 74 connected to various parts of the power transmission path PT including the automatic transmission 22, and a cooler oil passage 76 connected to the oil cooler 54. The AT / LU hydraulic control system 64 configured in this way controls the supply and discharge of hydraulic oil for the operation of the automatic transmission 22 and the torque converter 20 with the lock-up clutch LU via the solenoid valves 68. The operations related to the automatic transmission 22 and the torque converter 20 with lock-up clutch LU include, for example, maintaining the gear ratio γat of the automatic transmission 22, shifting gears of the automatic transmission 22, lubrication of each part by hydraulic oil via the lubrication oil passage 74, warming up and cooling the hydraulic oil via the oil cooler 54, and controlling the engagement and disengagement of the lock-up clutch LU.

[0024] The K0 hydraulic control system 66 includes a solenoid valve 78 that regulates the pressure of the hydraulic fluid OIL supplied to the clutch K0. The K0 hydraulic control system 66 controls the operation of the clutch K0 by controlling the supply and discharge of hydraulic fluid OIL for the operation of the clutch K0 via the solenoid valve 78. The operation of the clutch K0 is, for example, the control of opening and closing the clutch K0. The hydraulic fluid OIL discharged in conjunction with the operation of the solenoid valves 68 and 78, the hydraulic fluid OIL supplied to each part of the power transmission path PT including the automatic transmission 22 via the lubrication oil passage 74, and the hydraulic fluid OIL discharged from the oil cooler 54 are returned to the oil pan 52 via the respective drain oil passages 80, 82, and 84.

[0025] Returning to Figure 1, the vehicle 10 can switch between a manual driving mode and an automatic driving mode, meaning it can be selectively selected between the two. The manual driving mode is a driving method based on the driver's manual operation, while the automatic driving mode is a driving method that is not based on the driver's manual operation. In the automatic driving mode, the vehicle 10 is controlled to drive toward a target position based on a preset target position (=target position information) and current position (=current position information), etc., without depending on the driver's operation. In this invention, "automatic driving" means that at least acceleration and deceleration are controlled without depending on the driver's manual operation.

[0026] During manual driving mode, i.e., manual driving, the requested drive amount requested by the driver from the vehicle 10 is calculated by applying, for example, the accelerator opening θacc[%] operated by the driver and the actual vehicle speed V[km / h] to the drive request amount map. The drive request amount map is a map in which the relationship between the accelerator opening θacc, vehicle speed V and the drive request amount is experimentally or design-driven and predetermined and stored. The drive request amount is the load on the power source (for example, the requested drive torque Trdem[Nm], which is the amount of drive torque Tr[Nm] required for a pair of drive wheels 14), and corresponds to the "power load" in this invention. The engine torque Te[Nm], which is the output torque of the engine 12, the MG torque Tmg[Nm], which is the output torque of the electric motor MG, and the gear ratio γat of the automatic transmission 22 are controlled to realize the requested drive torque Trdem. For example, when driving as a BEV and in manual driving mode, the MG torque Tmg is controlled to realize the requested drive torque Trdem based on the driver's manual operation. At this time, if it is determined that the required drive torque Trdem cannot be achieved with MG torque Tmg alone, the engine 12 is started and the vehicle switches from BEV driving to engine driving. This allows the engine torque Te to be used in addition to the MG torque Tmg to achieve the required drive torque Trdem, thereby achieving the required drive torque Trdem. The request to switch from BEV driving to engine driving during manual driving is due to an increase in the required drive torque Trdem based on the driver's manual operation, so the engine must be started with good responsiveness. If the engine is started with good responsiveness, there is a risk of shock occurring as the drive torque Tr transmitted from the power transmission path PT to the pair of drive wheels 14 increases in a short period of time. To suppress the occurrence of this shock, it is necessary to release the lock-up clutch LU and transmit power within the torque converter 20 via fluid.

[0027] During autonomous driving, i.e., while driving autonomously, the system uses, for example, map data pre-stored in the navigation system, the current position of vehicle 10, surrounding information of vehicle 10 (such as the position and direction of other vehicles), and the vehicle speed V and acceleration Acc [m / sec] of vehicle 10. 2 Based on the above, a driving plan for vehicle 10 along the target route set by the driver is created, that is, the path of vehicle 10 is determined.

[0028] Based on the vehicle 10's path and the aforementioned map data, the inclination angle of the road the vehicle 10 will travel on is acquired, and the future required drive torque Trdem is predicted according to the current vehicle speed V and the inclination angle of the road the vehicle 10 will travel on. In this way, during autonomous driving, the future required drive torque Trdem is predicted from the driving plan, and the engine 12 and electric motor MG are automatically controlled so that the actual drive torque Tr matches the predicted required drive torque Trdem.

[0029] For example, when driving in BEV mode and autonomous driving mode, the MG torque Tmg is controlled to achieve the predicted required drive torque Trdem. If it is predicted that the future required drive torque Trdem will be greater than a predetermined torque determination value Trdem_jdg, the engine 12 is started in advance and the vehicle switches from BEV driving to engine driving. The predetermined torque determination value Trdem_jdg is a predetermined determination value that is experimentally or design-wise determined in advance to determine that the future required drive torque Trdem cannot be achieved with MG torque Tmg alone. The predetermined torque determination value Trdem_jdg corresponds to the "predetermined load determination amount" in this invention. Thus, the switch from BEV driving to engine driving during autonomous driving is performed, for example, based on the prediction that the required drive torque Trdem during autonomous driving will be greater than a predetermined torque determination value Trdem_jdg.

[0030] For example, when the vehicle is in BEV mode and autonomous driving mode, if it is predicted that the future charge state value (SOC) [%] will fall below a predetermined engine start threshold (SOC_jdg), the engine 12 is started in advance to switch from BEV mode to engine mode. The charge state value (SOC) is the ratio of the actual amount of charge stored to the fully charged capacity of the battery 44, which is predetermined. The predetermined engine start threshold (SOC_jdg) is a predetermined threshold used to determine that the charge state value (SOC) requires the engine 12 to be automatically started to charge the battery 44.

[0031] Since the request to switch from BEV driving to engine driving during autonomous driving is known in advance based on the vehicle 10's driving plan, the time required for engine starting is set to be longer than that for switching from BEV driving to engine driving during manual driving. In autonomous driving, since the engine 12 only needs to be started over such a long period, it is not necessary for the engine to start with high responsiveness. Therefore, in autonomous driving, the engine start is performed over the aforementioned long period so as to suppress shocks generated in the power transmission path PT compared to switching from BEV driving to engine driving during manual driving.

[0032] The electronic control unit 100 is composed of a so-called microcomputer, for example, equipped with a CPU, RAM, ROM, input / output interface, etc. The CPU performs various controls on the vehicle 10 by processing signals according to a program pre-stored in ROM while utilizing the temporary storage function of RAM. The electronic control unit 100 corresponds to the "control device" in this invention.

[0033] The electronic control unit 100 receives various signals based on detection values ​​from various sensors (for example, engine rotation speed sensor 90, input shaft rotation speed sensor 92, output shaft rotation speed sensor 94, MG rotation speed sensor 96, accelerator opening sensor 98, battery sensor 88, etc.). These signals include, for example, engine rotation speed Ne [rpm], input shaft rotation speed Nin [rpm] which is the same as turbine rotation speed Nt, output shaft rotation speed Nout which corresponds to vehicle speed V, MG rotation speed Nmg [rpm] which is the same as pump rotation speed Np, accelerator opening θacc which is the amount of accelerator operation by the driver representing the magnitude of the driver's acceleration operation, and the charge state value SOC of the battery 44. The engine rotation speed Ne is the rotation speed of the engine 12, and the turbine rotation speed Nt is the rotation speed of the turbine impeller 20b. The input shaft rotation speed Nin is the rotation speed of the input shaft 32. The pump rotation speed Np is the rotation speed of the pump impeller 20a, and the MG rotation speed Nmg is the rotation speed of the electric motor MG.

[0034] The electronic control unit 100 outputs various command signals (for example, an engine control signal Se for controlling the engine 12, a gear shift control signal Sat for controlling the gear shift of the automatic transmission 22, a LU control signal Slu for controlling the engagement and disengagement of the lock-up clutch LU, a K0 control signal Sk0 for controlling the engagement and disengagement of the clutch K0, an MG control signal Smg for controlling the rotation of the electric motor MG via the inverter 42, and a starter motor control signal Ss for controlling the rotation of the starter motor 46) to each device installed in the vehicle 10 (for example, the engine 12, the hydraulic control circuit 40, the inverter 42, the starter motor control signal Ss, etc.).

[0035] The electronic control unit 100 functionally includes a BEV driving determination unit 102, a driving mode determination unit 104, and a lock-up clutch control unit 106.

[0036] The BEV driving determination unit 102 determines whether or not the vehicle 10 is in BEV mode.

[0037] The driving mode determination unit 104 determines whether or not the vehicle 10 is in autonomous driving mode.

[0038] If the BEV driving determination unit 102 determines that the vehicle is in BEV mode and the driving mode determination unit 104 determines that the vehicle is in autonomous driving mode, the lock-up clutch control unit 106 controls the lock-up clutch LU to the engaged state.

[0039] If the BEV driving determination unit 102 determines that the vehicle is not in BEV mode, or if the driving mode determination unit 104 determines that the vehicle is in manual driving mode, the lock-up clutch control unit 106 controls the engagement / disengagement state of the lock-up clutch LU according to predetermined engagement / disengagement conditions. These predetermined engagement / disengagement conditions are, for example, predetermined lock-up switching maps.

[0040] Figure 3 shows an example of a lock-up switching map, which is predetermined as the engagement and disengagement conditions for the lock-up clutch LU. In Figure 3, the engagement and disengagement state of the lock-up clutch LU is set based on the vehicle state of the vehicle 10, which is represented on a two-dimensional coordinate system of output shaft rotation speed Nout and accelerator opening θacc. In the lock-up switching map, vehicle speed V may be used instead of output shaft rotation speed Nout, and throttle valve opening θth or required drive torque Trdem may be used instead of accelerator opening θacc.

[0041] The lock-up switching map has predetermined on-to-off switching lines that switch the lock-up clutch LU from the engaged state (=on state) to the released state (=off state), and off-to-on switching lines that switch the lock-up clutch LU from the released state (=off state) to the engaged state (=on state). For example, in Figure 3, when the points represented by the variables actual output shaft rotation speed Nout and accelerator opening θacc cross the on-to-off switching line or the off-to-on switching line, it is determined that the lock-up clutch LU release control or engagement control has started.

[0042] Figure 4 is an example of a flowchart illustrating the control operation of the electronic control unit 100 shown in Figure 1. The flowchart in Figure 4 is executed repeatedly while the vehicle is in motion.

[0043] First, in step S10, which corresponds to the function of the BEV driving determination unit 102 (the step will be omitted hereafter), it is determined whether or not the vehicle 10 is driving in BEV mode. If the determination in S10 is YES, in S20, which corresponds to the function of the driving mode determination unit 104, it is determined whether or not the vehicle 10 is driving in autonomous mode. If the determination in S20 is YES, in S30, which corresponds to the function of the lock-up clutch control unit 106, the lock-up clutch LU is controlled to be engaged. If the determination in S10 is NO and the determination in S20 is NO, in both cases, in S40, which corresponds to the function of the lock-up clutch control unit 106, the engagement and disengagement state of the lock-up clutch LU is controlled according to the lock-up switching map. After the execution of S30 and S40, the system returns.

[0044] According to this embodiment, (a) automatic driving and manual driving are switchable, (b) during BEV driving and manual driving, the lock-up clutch LU is engaged and disengaged according to the lock-up switching map, and (c) during BEV driving and automatic driving, the lock-up clutch LU is engaged. This makes it possible to start the engine quickly during manual driving and to accurately control the drive torque Tr and rotational speed of the pair of drive wheels 14 during automatic driving.

[0045] According to this embodiment, the switch from BEV driving to engine driving during autonomous driving is performed based on the prediction that the required drive torque Trdem during autonomous driving will be greater than a predetermined torque determination value Trdem_jdg. Since the switch from BEV driving to engine driving during autonomous driving is performed in advance based on the prediction of the required drive torque Trdem, the responsiveness of engine starting is not required to the same extent as during manual driving. Therefore, even if the lock-up clutch LU is engaged during autonomous driving and BEV driving, the occurrence of shock due to the switch from BEV driving to engine driving is suppressed.

[0046] According to this embodiment, the switch from BEV driving to engine driving during autonomous driving is performed based on the prediction that the charge state value (SOC) of the battery 44, which exchanges power with the electric motor MG, will fall below the engine start threshold (SOC_jdg). Since the switch from BEV driving to engine driving during autonomous driving is performed in advance based on the prediction of the charge state value (SOC), the responsiveness of engine starting is not as required as during manual driving. Therefore, even if the lock-up clutch LU is engaged during autonomous driving and BEV driving, the occurrence of shock due to the switch from BEV driving to engine driving is suppressed.

[0047] In this embodiment, both during manual driving and engine-driven driving, the lock-up clutch LU is engaged and disengaged according to a predetermined lock-up switching map. This suppresses the occurrence of shocks, allows for responsive engine starting, and facilitates improved fuel efficiency of the engine 12 during engine-driven driving.

[0048] The above-described examples are embodiments of the present invention, and the present invention can be implemented in various modified and improved forms based on the knowledge of those skilled in the art, without departing from its spirit. [Explanation of Symbols]

[0049] 10: Hybrid vehicle, 12: Engine, 14: Pair of drive wheels, 20: Torque converter, 44: Battery, 100: Electronic control unit (control unit), LU: Lock-up clutch, MG: Electric motor, PT: Power transmission path, SOC: Charge state value, SOC_jdg: Engine start threshold, Trdem: Required drive torque (power load), Trdem_jdg: Predetermined torque judgment value (predetermined load judgment amount)

Claims

1. A control device for a hybrid vehicle comprising an engine and an electric motor as power sources for driving, and a torque converter with a lock-up clutch provided in the power transmission path between the electric motor and a pair of drive wheels, It is possible to switch between autonomous driving and manual driving. During BEV operation where the power source is solely the electric motor and during manual operation, the lock-up clutch is controlled to engage and disengage according to predetermined engagement and disengagement conditions. During BEV driving and autonomous driving, the lock-up clutch is engaged. A control device for a hybrid vehicle characterized by the following features.

2. The switch from BEV driving to engine driving, which includes at least the engine as the power source, during the autonomous driving operation is performed based on the prediction that the power load during the autonomous driving operation will exceed a predetermined load determination amount. The control device for a hybrid vehicle according to feature 1.

3. The switch from BEV driving to engine driving, which includes at least the engine as the power source, during the aforementioned autonomous driving is performed based on the prediction that the charge state value of the battery, which exchanges power with the electric motor, will fall below the engine starting threshold. The control device for a hybrid vehicle according to feature 1.

4. When the engine is running and the power source includes at least the engine, the lock-up clutch is controlled to engage and disengage according to the predetermined disengagement conditions. A control device for a hybrid vehicle according to any one of claims 1 to 3.

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