JP2025041457A - Vehicle control device - Google Patents

Abstract

A vehicle control device is provided that can reflect a user's intention regarding vehicle tracking and drivability.
[Solution] The vehicle control device of the present invention is equipped with an engine and a rotating electric motor, and is capable of switching between EV driving, which runs using the power of the rotating electric motor, and HV driving, which runs using the power of the engine and the rotating electric motor, and is a vehicle control device that can selectively perform fully autonomous driving and platoon driving, and when platoon driving in EV driving, the timing of engine start-up or gear shifting is made earlier than when fully autonomous driving driving in EV driving.
[Selected figure] Figure 3

Description

The present invention relates to a vehicle control device.

Patent document 1 discloses a vehicle that follows a preceding vehicle.

JP 2019-162987 A

In the vehicle disclosed in Patent Document 1, in a hybrid vehicle, when the timing of engine start and gear shifting at the time of switching from EV driving to HV driving is the same during platooning and fully autonomous driving, the vehicle does not reflect the user's intentions regarding tracking and drivability.

The present invention was made in consideration of the above problems, and its purpose is to provide a vehicle control device that can reflect the user's intentions regarding tracking and drivability.

In order to solve the above-mentioned problems and achieve the object, the vehicle control device of the present invention is a vehicle control device that is provided with an engine and a rotating electric machine, and is capable of switching between EV driving, which runs using the power of the rotating electric machine, and HV driving, which runs using the power of the engine and the rotating electric machine, and is capable of selectively performing fully autonomous driving driving and platoon driving, and is characterized in that when the platoon driving is in EV driving, the timing of engine start or gear shift is made earlier than when the fully autonomous driving driving is in EV driving.

The vehicle control device according to the present invention has the effect of being able to reflect the user's intentions regarding tracking and drivability.

FIG. 1 is a diagram for explaining the schematic configuration of a power transmission device provided in a vehicle to which the present invention is applied, and is also a diagram for explaining the main parts of a control system for various controls in the vehicle. FIG. 2 is a diagram illustrating a schematic configuration of a hydraulic system that is provided in a vehicle and controls operations related to the transmission and the clutch K0. FIG. 3 is a flowchart showing an example of control performed by the electronic control unit according to the embodiment.

The following describes an embodiment of a vehicle control device according to the present invention. Note that the present invention is not limited to this embodiment.

1 is a diagram illustrating the schematic configuration of a power transmission device 12 provided in a vehicle 10 to which the present invention is applied, and is also a diagram illustrating the main parts of a control system for various controls in the vehicle 10. In FIG. 1, the vehicle 10 is a hybrid vehicle equipped with an engine 14 and a rotating electric machine MG that function as a driving force source for traveling. The power transmission device 12 includes, in order from the engine 14 side, an engine disconnection clutch K0 (hereinafter referred to as clutch K0), a torque converter 18, and an automatic transmission 20 in a transmission case 16 as a non-rotating member. The power transmission device 12 also includes a propeller shaft 24 connected to a transmission output shaft 22, which is an output rotating member of the automatic transmission 20, a differential gear 26 connected to the propeller shaft 24, and a pair of axles 28 connected to the differential gear 26. The pump impeller 18a of the torque converter 18 is connected to an engine connecting shaft 30 via the clutch K0, and is also directly connected to the rotating electric machine MG. The turbine wheel 18b of the torque converter 18 is directly connected to the transmission input shaft 32, which is the input rotating member of the automatic transmission 20. The power transmission device 12 configured in this manner is preferably used, for example, in an FR vehicle 10. In the power transmission device 12, when the clutch K0 is engaged, the power of the engine 14 (torque or force is also synonymous with the engine 14 when no particular distinction is made) is transmitted from the engine connecting shaft 30 that connects the engine 14 and the clutch K0 to a pair of drive wheels 34 via the clutch K0, the torque converter 18, the automatic transmission 20, the propeller shaft 24, the differential gear 26, and a pair of axles 28, etc. In this manner, the power transmission device 12 constitutes a power transmission path from the engine 14 to the drive wheels 34.

The vehicle 10 is also equipped with a mechanical oil pump 36 connected to the pump impeller 18a, a hydraulic control circuit 40 that controls the shifting operation of the automatic transmission 20, the engagement and release operation of the clutch K0, and the engagement and release operation of a known lock-up clutch LU (hereinafter referred to as clutch LU) provided in the torque converter 18, an inverter 42 that controls the operation of the rotating electric machine MG, an electricity storage device 44 that exchanges electricity with the rotating electric machine MG via the inverter 42, and a starter 46 that drives the engine 14 to rotate when the engine is started.

The automatic transmission 20 is interposed in the power transmission path between the torque converter 18 and the drive wheels 34, constitutes a part of the power transmission path between the engine 14 and the drive wheels 34, and is a transmission that transmits power from the driving power source (engine 14 and rotating electric machine MG) to the drive wheels 34. The automatic transmission 20 is, for example, a known planetary gear type multi-speed transmission in which multiple gears with different gear ratios γ (= transmission input shaft rotation speed Nin/transmission output shaft rotation speed Nout) are selectively established, or a known continuously variable transmission in which the gear ratio γ is continuously changed steplessly. In the automatic transmission 20, for example, a hydraulic actuator is controlled by a hydraulic control circuit 40 to establish a predetermined gear ratio γ according to the accelerator opening θacc, the vehicle speed V, etc. The torque converter 18 can also be considered as part of the above-mentioned transmission. In other words, the automatic transmission 20 equipped with the torque converter 18 can be considered as the transmission that constitutes part of the power transmission path.

The rotating electric machine MG is a so-called motor generator that has a function as a motor that generates mechanical power from electrical energy, and a function as a generator that generates electrical energy from mechanical energy. The rotating electric machine MG generates power for running using electric power (when no special distinction is made, the same applies to electric energy) supplied from the power storage device 44 via the inverter 42 instead of or in addition to the engine 14. The rotating electric machine MG converts the power of the engine 14 and the driven force input from the drive wheels 34 side into electric power by regeneration, and stores the electric power in the power storage device 44 via the inverter 42. The rotating electric machine MG is provided in the power transmission path between the engine 14 and the drive wheels 34, and is connected to the power transmission path between the clutch K0 and the torque converter 18, and power is transmitted between the rotating electric machine MG and the pump impeller 18a. In this way, the rotating electric machine MG is connected to the transmission input shaft 32 of the automatic transmission 20 so as to be capable of transmitting power without passing through the clutch K0.

The clutch K0 is, for example, a wet-type multi-plate hydraulic friction engagement device, and is controlled for engagement and disengagement by the hydraulic control circuit 40 using the hydraulic pressure generated by the oil pump 36 as the base pressure. In this engagement and disengagement control, the torque capacity of the clutch K0 (hereinafter referred to as K0 torque) is changed by, for example, adjusting the pressure of a solenoid valve or the like in the hydraulic control circuit 40. When the clutch K0 is in an engaged state, the pump impeller 18a and the engine 14 are rotated together via the engine connecting shaft 30. On the other hand, when the clutch K0 is in a released state, the power transmission between the engine 14 and the pump impeller 18a is interrupted. In other words, the engine 14 and the drive wheels 34 are separated by releasing the clutch K0. Since the rotating electric machine MG is connected to the pump impeller 18a, the clutch K0 is provided in the power transmission path between the engine 14 and the rotating electric machine MG, and also functions as a clutch that connects and disconnects the power transmission path, that is, a clutch that connects and disconnects the engine 14 from the rotating electric machine MG.

2 is a diagram illustrating the schematic configuration of a hydraulic system 50 that controls the operation of the transmission (automatic transmission 20, torque converter 18) and clutch K0 provided in the vehicle 10. In FIG. 2, in addition to the oil pump 36 and hydraulic control circuit 40 described above, the hydraulic system 50 includes an oil pan 52 provided at the bottom of the transmission case 16, and an oil cooler 54 that warms the hydraulic oil when it is cold and cools the hydraulic oil after warm-up is complete. The oil pump 36 is driven to rotate by the engine 14 and/or the rotating electric machine MG to generate the source pressure of the hydraulic oil (i.e., the hydraulic oil pressure for executing the shift control of the automatic transmission 20, the engagement/release control of the clutch LU, and the engagement/release control of the clutch K0, etc.) that is supplied to the hydraulic control circuit 40. In this way, the oil pump 36 is driven by the rotation of the pump impeller 18a, which is one of the rotating members between the clutch K0 and the drive wheels 34 and is rotated by the engine 14 and/or the rotating electric machine MG, to supply hydraulic oil to the clutch K0 and the transmission (automatic transmission 20, torque converter 18). The oil pump 36 sucks up the hydraulic oil that has returned to the oil pan 52 from an intake port (strainer) 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 the line pressure PL flows).

The hydraulic control circuit 40 includes a primary regulator valve 62 that adjusts the line pressure PL using the hydraulic pressure output (generated) from the oil pump 36 as the base pressure, an AT/LU hydraulic control system 64 that controls the shift operation of the automatic transmission 20 and the engagement and release operation of the clutch LU using the line pressure PL as the base pressure, and a K0 hydraulic control system 66 that controls the engagement and release operation of the clutch K0 using the line pressure PL as the base pressure.

The AT/LU hydraulic control system 64 includes a plurality of solenoid valves 68 that adjust the pressure of hydraulic oil supplied to the hydraulic actuator in the automatic transmission 20, control the hydraulic oil supplied to the clutch LU, switch the oil passage through which the hydraulic oil flows, open the oil passage, and block the oil passage. The above oil passages include, for example, an oil passage 70 connected to the hydraulic actuator in the automatic transmission 20, an oil passage 72 connected to the clutch LU, a lubricating oil passage 74 connected to each part of the power transmission path including the automatic transmission 20, and a cooler oil passage 76 connected to the oil cooler 54. The AT/LU hydraulic control system 64 configured in this manner controls the supply and discharge of hydraulic oil for operation related to the transmission (automatic transmission 20, torque converter 18) via the solenoid valves 68, thereby controlling the operation related to the transmission. The operations related to this transmission (automatic transmission 20, torque converter 18) include, for example, maintaining the gear ratio γ of the automatic transmission 20, the shifting operation of the automatic transmission 20, lubrication of each part with hydraulic oil via the lubricating oil passage 74, warming and cooling of the hydraulic oil via the oil cooler 54, and the engagement and release operation of the clutch LU. The K0 hydraulic control system 66 includes a solenoid valve 78 that adjusts the pressure of the hydraulic oil supplied to the clutch K0. The K0 hydraulic control system 66 configured in this manner controls the supply and discharge of hydraulic oil for operations related to the clutch K0 via the solenoid valve 78, thereby controlling the operations related to the clutch K0. The operations related to this clutch K0 include, for example, the engagement and release operation of the clutch K0. The hydraulic oil discharged with the operation of the solenoid valves 68, 78, the hydraulic oil supplied to each part of the power transmission path including the automatic transmission 20 via the lubricating oil passage 74, and the hydraulic oil discharged from the oil cooler 54 are returned to the oil pan 52 via each drain oil passage 80, 82, 84.

Returning to FIG. 1, the vehicle 10 is equipped with an electronic control device 100 including a control device for the vehicle 10 related to, for example, clutch K0 engagement/release control and engine 14 start control. The electronic control device 100 is configured to include, for example, a so-called microcomputer equipped with a CPU, RAM, ROM, and an input/output interface. The CPU executes various controls of the vehicle 10 by performing signal processing according to a program previously stored in the ROM while utilizing the temporary storage function of the RAM. For example, the electronic control device 100 executes output control of the engine 14, drive control of the rotating electric machine MG including regenerative control of the rotating electric machine MG, shift control of the automatic transmission 20, and K0 torque control, and is configured to be divided into engine control, rotating electric machine control, hydraulic control, etc. as necessary. The electronic control device 100 is supplied with various signals (e.g., engine rotation speed Ne, turbine rotation speed Nt, i.e., transmission input shaft rotation speed Nin, transmission output shaft rotation speed Nout corresponding to vehicle speed V, pump rotation speed Np, i.e., rotating electric machine rotation speed (MG rotation speed) Nm, accelerator opening θacc corresponding to the amount of drive required of the vehicle 10 by the driver, and state of charge (charging capacity) SOC of the storage device 44) based on detection values by various sensors (e.g., crank position sensor 90, turbine rotation speed sensor 92, output shaft rotation speed sensor 94, rotating electric machine rotation speed sensor 96, accelerator opening sensor 98, and battery sensor 99, etc.). From the electronic control device 100, for example, an engine output control command signal Se for controlling the output of the engine 14, a rotating electric machine control command signal Sm for controlling the operation of the rotating electric machine MG, a hydraulic control command signal Sp for operating solenoid valves 68, 78, etc. included in the hydraulic control circuit 40 to control the clutch K0, the hydraulic actuator of the automatic transmission 20, the clutch LU, etc., and a starter command signal Ss for driving control of the starter 46 that rotates and drives the engine 14 when the engine is started are output to the engine control devices such as the fuel injection device, the ignition device, and the throttle actuator, the inverter 42, the hydraulic control circuit 40, and the starter 46, etc.

The electronic control unit 100 also includes a gear shift control unit 102, which is a gear shift control means, and a hybrid control unit 104, which is a hybrid control means.

The shift control unit 102 determines the gear ratio γ of the automatic transmission 20 to be established based on the vehicle state (e.g., actual vehicle speed V and accelerator opening θacc, etc.) from a known relationship (shift line diagram, shift map; not shown) that is experimentally or design-wise determined and stored (i.e., predetermined) using the vehicle speed V and the drive demand amount (e.g., accelerator opening θacc, etc.) as variables, and outputs a shift command value to the hydraulic control circuit 40 to obtain the determined gear ratio γ, thereby executing automatic shift control of the automatic transmission 20. This shift command value is one of the hydraulic control command signals Sp.

The hybrid control unit 104 includes a function as an engine drive control unit that controls the drive of the engine 14 and a function as a rotating electric machine operation control unit that controls the operation of the rotating electric machine MG as a driving force source or a generator via the inverter 42, and executes hybrid drive control by the engine 14 and the rotating electric machine MG using these control functions. For example, the hybrid control unit 104 calculates the required driving force as the amount of drive required by the driver for the vehicle 10 based on the accelerator opening θacc and the vehicle speed V. Then, the hybrid control unit 104 outputs command signals (engine output control command signal Se and rotating electric machine control command signal Sm) that control the driving force source for driving so that the required driving force is the output of the driving force source for driving (engine 14 and rotating electric machine MG) that is obtained, taking into account the transmission loss, the auxiliary load, the gear ratio γ of the automatic transmission 20, and the charging capacity SOC of the storage device 44. As the drive demand amount, in addition to the required drive force [N] at the drive wheels 34, the required drive torque [Nm] at the drive wheels 34, the required drive power [W] at the drive wheels 34, the required transmission output torque at the transmission output shaft 22, etc. can also be used. Also, as the drive demand amount, it is possible to simply use the accelerator opening θacc [%], the throttle valve opening [%], the intake air amount [g/sec], etc.

Specifically, for example, when the required driving force is within a range that can be met only by the output of the rotating electric machine MG, the hybrid control unit 104 sets the driving mode to a motor driving mode (EV driving mode), and performs motor driving (EV driving) in which only the rotating electric machine MG is used as a driving force source for driving with the clutch K0 released. On the other hand, for example, when the required driving force is within a range that cannot be met without at least using the output of the engine 14, the hybrid control unit 104 sets the driving mode to an engine driving mode, i.e., a hybrid driving mode (HV driving mode), and performs engine driving, i.e., hybrid driving (HV driving), in which at least the engine 14 is used as a driving force source for driving with the clutch K0 engaged. On the other hand, for example, even if the required driving force is within a range that can be met only by the output of the rotating electric machine MG, the hybrid control unit 104 performs HV driving when it is necessary to warm up the engine 14 or devices related to the engine 14. In this way, the hybrid control unit 104 automatically stops the engine 14 during engine driving and restarts the engine 14 after the engine has stopped, based on the required driving force, etc., to switch between EV driving and HV driving.

When the hybrid control unit 104 determines that there is an engine start request, for example, due to an increase in the required driving torque during EV driving or the need for warming up, it executes a series of operations related to starting the engine 14. Specifically, when the hybrid control unit 104 determines that there is an engine start request, it outputs a starter command signal Ss to the starter 46 to start the engine 14 by rotating (cranking) the engine 14 with the starter 46 while keeping the clutch K0 in a released state. In addition, the hybrid control unit 104 outputs an engine start command to engine control devices such as a fuel injection device, an ignition device, and a throttle actuator to start the engine 14 by executing electronic throttle valve opening/closing control, fuel supply control, and ignition timing control in conjunction with the cranking of the engine 14 by the starter 46. This engine start command is one of the engine output control command signals Se. In addition, the hybrid control unit 104 determines whether the starting of the engine 14 is complete based on whether the engine rotation speed Ne has increased to or above a predetermined rotation speed at which it can be determined that the engine 14 has completely exploded (i.e., the engine 14 has entered a state where it can operate autonomously). When the hybrid control unit 104 determines that the starting of the engine 14 is complete, it outputs a clutch K0 engagement command to engage the clutch K0 as an instruction to control the clutch K0, thereby controlling the released clutch K0 toward engagement.

The vehicle 10 according to the embodiment is an autonomous vehicle capable of performing all dynamic driving tasks on the vehicle side. Here, "autonomous driving" means that the vehicle performs almost all dynamic driving tasks, and means, for example, any of levels 3 to 5 defined by the Society of Automotive Engineers (SAE) in the United States. Level 3 is a driving mode in which all dynamic driving tasks are automated in specific locations such as highways, but in emergencies, the driver's operation is required. Level 4 is a driving mode in which all dynamic driving tasks are automated only in specific locations, and emergency responses are also handled automatically. Level 5 is a driving mode in which autonomous driving is possible under almost all conditions without restrictions such as location, and means so-called "fully autonomous driving." Note that autonomous driving can be selectively performed, for example, by switch operation by the driver or passenger, or by signals from various sensors.

The vehicle 10 according to the embodiment is capable of platooning following a preceding vehicle without the driver's operation. Specifically, the vehicle is configured to be able to drive while maintaining an appropriate distance from the preceding vehicle by controlling the driving force and braking force without the driver having to operate the accelerator or brake. Examples of controls that can perform such following driving include conventionally known cruise control, adaptive cruise control that maintains a constant distance from the preceding vehicle and stops the vehicle when the preceding vehicle stops, and communication-cooperative adaptive cruise control that uses vehicle-to-vehicle communication to set a relatively short distance between the vehicle and the preceding vehicle, enabling the vehicle to platoon with the preceding vehicle. Note that these cruise control controls can be selectively performed, for example, by a switch operation by the driver or passenger, or by signals from various sensors.

In the vehicle 10 according to the embodiment, when accelerating during EV driving, engine start and downshifting to switch to HV driving may occur simultaneously. In this case, hydraulic pressure is required for both starting the engine and switching to HV driving and for shifting, so it is necessary to wait for either engine start or shifting to occur.

Figure 3 is a flowchart showing an example of control performed by the electronic control device 100 according to the embodiment. Note that Figure 3 shows a case in which the vehicle 10 is running in EV mode and can selectively perform fully autonomous driving as the autonomous driving mode.

First, the electronic control unit 100 judges whether or not fully automatic driving has been selected (step S1). When the electronic control unit 100 judges that fully automatic driving has been selected (Yes in step S1), it judges whether or not engine start and gear shifting are requested simultaneously (step S2). When the electronic control unit 100 judges that engine start and gear shifting are requested simultaneously (Yes in step S2), it delays engine start or gear shifting more than normal control and executes engine start and gear shifting (step S3). Then, the electronic control unit 100 ends the series of controls. On the other hand, when the electronic control unit 100 judges that engine start and gear shifting are not requested simultaneously (No in step S2), it executes engine start and gear shifting without delaying engine start or gear shifting (step S4). Then, the electronic control unit 100 ends the series of controls.

In addition, in the process of step S1, if the electronic control unit 100 determines that the fully automated driving has not been selected (No in step S1), it determines whether or not the platoon driving has been selected (step S5). If the electronic control unit 100 determines that the platoon driving has been selected (Yes in step S5), it determines whether or not the preceding vehicle is scheduled to accelerate (step S6). If the electronic control unit 100 determines that the preceding vehicle is scheduled to accelerate (Yes in step S6), it advances the timing of engine start or gear shift compared to the fully automated driving driving, and performs engine start or gear shift with foresight (step S7). After that, the electronic control unit 100 ends the series of controls. On the other hand, if the electronic control unit 100 determines that the platoon driving has not been selected (No in step S5) or that the preceding vehicle is not scheduled to accelerate (No in step S6), it does not perform engine start or gear shift with foresight (step S8). After that, the electronic control unit 100 ends the series of controls.

The electronic control device 100 according to the embodiment can also perform the following control when the vehicle 10 is running in EV mode. That is, when fully automated driving is selected and engine start and gear shifting are requested simultaneously, the electronic control device 100 delays engine start beyond normal control and starts the engine after it stabilizes after the gear shift. This makes it possible to avoid an overlap between engine start and gear shifting, suppress gear shift shock, and prioritize drivability. Furthermore, when platooning is selected, the electronic control device 100 starts the engine before gear shifting when the preceding vehicle intends to accelerate and the host vehicle is predicted to start the engine and shift in the future. This makes it possible to avoid an overlap between engine start and gear shifting, prioritize acceleration response, and suppress separation from the platoon.

The electronic control device 100 according to the embodiment prioritizes drivability over acceleration response during fully automated driving, and prioritizes acceleration response during platooning so as not to separate from the preceding vehicle, thereby allowing the intention of the user (driver or passenger) regarding drivability and tracking to be reflected.

10 Vehicle 14 Engine 100 Electronic control device MG Rotating electric machine

Claims (1)

A control device for a vehicle that is provided with an engine and a rotating electric machine, that is capable of switching between EV driving using power from the rotating electric machine and HV driving using power from the engine and the rotating electric machine, and that is capable of selectively executing fully automated driving driving and platoon driving,
A vehicle control device characterized in that, when the vehicle is traveling in a platoon while driving in an EV mode, the timing of engine start or gear shift is made earlier than when the vehicle is traveling in a fully autonomous driving mode while driving in an EV mode.

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