Vehicle control device

Abstract

To provide a vehicle control device capable of reducing situations where continuation of traveling becomes impossible during retreat traveling.SOLUTION: A vehicle 10 comprises: an engine 12; a first electric motor MG1 which is constituted by a permanent magnet type motor generator and is rotated concurrently in the case of a non-drive state during traveling using the engine 12 as a power source; and a second electric motor MG2. During retreat traveling in an MDE traveling mode in which the first electric motor MG1 is put in the non-drive state, and the engine 12 and the second electric motor MG2 are used as power sources, an electronic control device 90 prohibits a regenerative brake by the second electric motor MG2 when a state-of-charge value SOC of a battery 40 exceeds a regeneration prohibition judgment value SOC_jdg1, and permits the regenerative brake by the second electric motor MG2 when the state-of-charge value SOC of the battery 40 is equal to or less than a regeneration permission judgment value SOC_jdg2.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a control device for a vehicle equipped with an engine as a power source for running, a first electric motor consisting of a permanent magnet motor generator that is rotated when not in a driven state while running using the engine as a power source, and a second electric motor that is also a power source for running. [Background technology]

[0002] There is known a control device for a vehicle including an engine as a power source for driving, a first electric motor configured as a permanent magnet motor generator and driven when the first electric motor is not driven while the vehicle is driving using the engine as a power source, a second electric motor as a power source for driving, a battery that exchanges power with the first electric motor via a first inverter and with the second electric motor via a second inverter, and a DC / DC converter provided between the first inverter, the second inverter, and the battery. For example, a control device is described in Patent Document 1. Patent Document 1 discloses that, when an abnormal state occurs in which the first inverter is not operating normally, the first electric motor is put into a non-driven state and evacuation driving is performed using the engine and the second electric motor as power sources. During this evacuation driving, the first electric motor generates electricity by being driven by the engine. This power generation charges the battery, thereby avoiding a situation in which the vehicle cannot continue driving due to insufficient battery charge. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-36593 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-described evacuation running disclosed in Patent Document 1, if regenerative braking by the second motor is permitted at all times, there is a risk that the battery will become overcharged and the vehicle will be unable to continue running. On the other hand, if regenerative braking by the second motor is prohibited at all times, there is a risk that the battery will become undercharged and the vehicle will be unable to continue running.

[0005] The present invention has been made in light of the above circumstances, and its purpose is to provide a vehicle control device that can reduce the number of situations in which it becomes impossible to continue driving during evacuation driving. [Means for solving the problem]

[0006] The gist of the present invention is a control device for a vehicle including an engine as a power source for driving, a first electric motor consisting of a permanent magnet motor generator and rotated in a non-driven state while the vehicle is driving using the engine as a power source, a second electric motor as a power source for driving, a battery that exchanges power with the first electric motor via a first inverter and with the second electric motor via a second inverter, and a DC / DC converter provided between the first inverter and the second inverter and the battery, wherein, while the first electric motor is in a non-driven state and the vehicle is driving using the engine and the second electric motor as power sources, if the state-of-charge value of the battery exceeds a predetermined first judgment value, regenerative braking by the second electric motor is prohibited, and if the state-of-charge value of the battery is equal to or less than a predetermined second judgment value, regenerative braking by the second electric motor is permitted. [Effects of the Invention]

[0007] According to the present invention, during traveling with the first electric motor in a non-driven state and the engine and the second electric motor being used as power sources, regenerative braking by the second electric motor is prohibited when the state-of-charge value of the battery exceeds a predetermined first judgment value, and regenerative braking by the second electric motor is permitted when the state-of-charge value of the battery is equal to or less than a predetermined second judgment value. When the state-of-charge value of the battery exceeds the predetermined first judgment value during evacuation traveling, the battery is in a state where it is likely to become overcharged. By prohibiting regenerative braking by the second electric motor, the battery is less likely to become overcharged in this state compared to when regenerative braking by the second electric motor is permitted. When the state-of-charge value of the battery is equal to or less than the predetermined second judgment value during evacuation traveling, the battery is more likely to become undercharged. By permitting regenerative braking by the second electric motor, the battery is less likely to become undercharged in this state compared to when regenerative braking by the second electric motor is prohibited. In this way, the battery is made less likely to be overcharged and less likely to be undercharged, reducing the number of situations in which it becomes impossible to continue driving during evacuation driving. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic configuration diagram of a vehicle equipped with an electronic control device according to an embodiment of the present invention; [Figure 2] 3 is an example of a flowchart illustrating a main part of the control operation of the electronic control device. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that in the embodiments, the drawings are appropriately simplified or modified, and the dimensional ratios and shapes of the various parts are not necessarily drawn accurately. [Example]

[0010] FIG. 1 is a schematic diagram of a vehicle 10 equipped with an electronic control device 90 according to an embodiment of the present invention.

[0011] In the vehicle 10, a power transmission path between an engine 12, which is a power source for driving, and a pair of drive wheels 14 is provided, in that order from the engine 12 side, with a power split device 20, a reduction mechanism 24, and a differential 26, all of which are well-known configurations. A second electric motor MG2, which is a power source for driving, is connected to an input side rotating member of the reduction mechanism 24 via a reduction gear 22 so as to be able to transmit power, all of which are well-known configurations. The vehicle 10 also has a first inverter 30, a second inverter 32, a DC / DC converter 50, and a battery 40, all of which are well-known configurations.

[0012] The engine 12 is a well-known internal combustion engine. The first electric motor MG1 is, for example, a three-phase synchronous motor such as a motor generator, which has at least a generator function among the functions of an electric motor and a generator. The first electric motor MG1 is a permanent magnet motor generator, and is configured to be rotated by the engine 12 when in a non-driven state during running using the engine 12 as a power source. The second electric motor MG2 is, for example, a three-phase synchronous motor such as a motor generator, which has a motor function and a generator function.

[0013] The power split mechanism 20 is configured with, for example, a single-pinion planetary gear device. For example, the power output from the engine 12 is mechanically split by the power split mechanism 20 to the first electric motor MG1 and the input-side rotating member of the reduction mechanism 24. In this specification, unless otherwise specified, the terms torque, driving force, power, and force (power) are synonymous.

[0014] The battery 40 is a well-known secondary battery that exchanges power with the first electric motor MG1 via a first inverter 30 and exchanges power with the second electric motor MG2 via a second inverter 32. The first inverter 30 and the second inverter 32 control the rotation of the first electric motor MG1 and the second electric motor MG2, respectively. The DC / DC converter 50 is a well-known power supply circuit that is provided between the battery 40 and the first inverter 30 or the second inverter 32 and that steps up or down the voltage of direct current.

[0015] The vehicle 10 is equipped with an electronic control device 90. The electronic control device 90 is configured to include a so-called microcomputer equipped with, for example, a CPU, RAM, ROM, an input / output interface, etc. The CPU performs signal processing according to a program pre-stored in the ROM while utilizing the temporary storage function of the RAM. The electronic control device 90 corresponds to the "control device" in this invention.

[0016] The electronic control device 90 receives various signals based on detected values ​​from various sensors (accelerator opening sensor 70, vehicle speed sensor 72, engine rotation speed sensor 74, first resolver 76, second resolver 78, first current sensor 80, second current sensor 82, battery sensor 84, etc.) including various signals (accelerator opening θacc [%] which is the amount of accelerator operation by the driver, which indicates the magnitude of the driver's acceleration operation, vehicle speed V [km / h], engine rotation speed Ne [rpm] which is the rotation speed of the engine 12, and the rotation speed of the first electric motor MG1. The inputs include a certain MG1 rotation speed Nmg1 [rpm], a rotation angle θmg1 [rad] representing the rotation position of the first motor MG1, an MG2 rotation speed Nmg2 [rpm] which is the rotation speed of the second motor MG2, a rotation angle θmg2 [rad] representing the rotation position of the second motor MG2, a first inverter current Iinv1 [A] which is the current flowing in the first inverter 30, a second inverter current Iinv2 [A] which is the current flowing in the second inverter 32, and a state of charge value SOC [%] of the battery 40. The state of charge value SOC is the ratio of the amount of charge actually stored to a predetermined full charge capacity of the battery 40.

[0017] The electronic control device 90 outputs various command signals (such as an engine control signal Se for controlling the operation of the engine 12, an MG1 control signal Smg1 for controlling the rotation of the first electric motor MG1 via the first inverter 30, an MG2 control signal Smg2 for controlling the rotation of the second electric motor MG2 via the second inverter 32, and a converter control signal Scon for voltage conversion control of the DC / DC converter 50) to each device of the vehicle 10 (such as the engine 12, the first inverter 30, the second inverter 32, and the DC / DC converter 50).

[0018] The electronic control device 90 controls the engine torque Te [N·m] that is the output torque of the engine 12, the MG1 torque Tmg1 [N·m] that is the output torque of the first electric motor MG1, and the MG2 torque Tmg2 [N·m] that is the output torque of the second electric motor MG2, so that the required drive torque Trdem [N·m] requested by the driver, for example, is transmitted to the pair of drive wheels 14. For example, the required drive torque Trdem requested by the driver for the pair of drive wheels 14 is calculated based on the accelerator opening θacc and the vehicle speed V.

[0019] The electronic control device 90 determines whether an abnormal state has occurred in which the rotation control of the first electric motor MG1 cannot be performed normally. For example, this abnormal state may include a case in which the first resolver 76 or the first inverter 30 has failed. For example, if the MG1 rotation speed Nmg1 or the rotation angle θmg1 is an abnormal value, it is determined that the first resolver 76 has failed. If the first inverter current Iinv1 is an abnormal value, it is determined that the first inverter 30 has failed.

[0020] When the electronic control device 90 determines that an abnormal state has occurred in which the rotation control of the first electric motor MG1 cannot be performed normally, the electronic control device 90 starts evacuation traveling in the MDE traveling mode. The "MDE traveling mode" is a traveling mode in which the first electric motor MG1 is in a non-driving state and the engine 12 and the second electric motor MG2 are used as power sources. During evacuation traveling in the MDE traveling mode, all of the switching elements (not shown) constituting the first inverter 30 are controlled to be in an off state. As a result, the first electric motor MG1 is in a non-driving state, the first electric motor MG1 is rotated by the engine 12, and the power generated by the first electric motor MG1 is charged to the battery 40. Note that the power generated by the first electric motor MG1 during this evacuation traveling is not controlled by the first inverter 30 but is based on the rotation speed of the MG1 rotated by the engine 12.

[0021] When evacuation traveling in the MDE traveling mode is started, the electronic control device 90 determines whether the state of charge value SOC is equal to or lower than a high charging determination value SOC_high and equal to or higher than a low charging determination value SOC_low. The "high charging determination value SOC_high" is the upper limit of the allowable range of the state of charge value SOC in the MDE traveling mode, and the "low charging determination value SOC_low" is the lower limit of the allowable range of the state of charge value SOC in the evacuation traveling in the MDE traveling mode. The high charging determination value SOC_high and the low charging determination value SOC_low are each determined in advance experimentally or by design. When the state of charge value SOC exceeds the high charging determination value SOC_high, the power generated by the first electric motor MG1 cannot be charged to the battery 40. Therefore, there is a risk of overvoltage occurring due to the generated power that cannot be charged to the battery 40, and therefore the evacuation traveling is stopped. When the state of charge value SOC falls below the low charge determination value SOC_low, the power supply from the battery 40 to the second electric motor MG2 via the DC / DC converter 50 becomes insufficient, or the power supply to the auxiliary equipment that controls the operation of the engine 12 becomes insufficient, and therefore the evacuation driving is stopped.

[0022] When evacuation traveling in the MDE traveling mode is started, the electronic control device 90 determines whether the state of charge value SOC exceeds a regeneration prohibition determination value SOC_jdg1. The "regeneration prohibition determination value SOC_jdg1" is a determination value of the state of charge value SOC that is determined in advance experimentally or by design in order to determine whether regenerative braking by the second electric motor MG2 should be prohibited. The regeneration prohibition determination value SOC_jdg1 corresponds to the "predetermined first determination value" in the present invention. When regenerative braking by the second electric motor MG2 is prohibited, the battery 40 is not charged with power generated by regeneration by the second electric motor MG2.

[0023] When evacuation traveling in the MDE traveling mode is started, the electronic control device 90 determines whether the state of charge value SOC is equal to or less than the regeneration permission determination value SOC_jdg2. The "regeneration permission determination value SOC_jdg2" is a determination value of the state of charge value SOC that is predetermined experimentally or by design in order to determine whether regenerative braking by the second electric motor MG2 is permitted. The regeneration permission determination value SOC_jdg2 corresponds to the "predetermined second determination value" in the present invention. When regenerative braking by the second electric motor MG2 is permitted, the battery 40 is charged with power generated by regeneration of the second electric motor MG2. The regeneration prohibition determination value SOC_jdg1 is smaller than the high charging determination value SOC_high. The regeneration permission determination value SOC_jdg2 is larger than the low charging determination value SOC_low. Furthermore, in this embodiment, the regeneration prohibition determination value SOC_jdg1 is larger than the regeneration permission determination value SOC_jdg2.

[0024] During evacuation traveling in the MDE traveling mode, the electronic control unit 90 suspends the evacuation traveling if the state of charge value SOC exceeds the high charging determination value SOC_high or if the state of charge value SOC is less than the low charging determination value SOC_low. During evacuation traveling in the MDE traveling mode, the electronic control unit 90 prohibits regenerative braking by the second electric motor MG2 if the state of charge value SOC is equal to or less than the high charging determination value SOC_high and exceeds the regeneration prohibition determination value SOC_jdg1. During evacuation traveling in the MDE traveling mode, the electronic control unit 90 permits regenerative braking by the second electric motor MG2 if the state of charge value SOC is equal to or greater than the low charging determination value SOC_low and is equal to or less than the regeneration permission determination value SOC_jdg2. The DC / DC converter 50 reduces the voltage of the power generated by regeneration of the second electric motor MG2 and charges the battery 40. During evacuation driving in the MDE driving mode, if the state of charge value SOC is less than or equal to the regeneration prohibition judgment value SOC_jdg1 and exceeds the regeneration permission judgment value SOC_jdg2, the electronic control device 90 maintains the state in which the use of regenerative braking by the second electric motor MG2 is permitted or prohibited.

[0025] Fig. 2 is an example of a flowchart illustrating the main control operations of the electronic control device 90. The flowchart in Fig. 2 starts when an abnormal state occurs in which the rotation control of the first electric motor MG1 cannot be performed normally (for example, when the first resolver 76 has failed).

[0026] First, in step S10 (hereinafter, step will be omitted), evacuation traveling in the MDE traveling mode is started. After execution of S10, in S20, it is determined whether or not the state of charge value SOC is equal to or less than a high charging determination value SOC_high and equal to or greater than a low charging determination value SOC_low. If the determination in S20 is NO, in S30, evacuation traveling is stopped, and the flowchart ends. If the determination in S20 is YES, in S40, it is determined whether or not the state of charge value SOC exceeds a regeneration prohibition determination value SOC_jdg1. If the determination in S40 is YES, in S50, regenerative braking by the second electric motor MG2 is prohibited. If the determination in S40 is NO, in S60, it is determined whether or not the state of charge value SOC is equal to or less than a regeneration permission determination value SOC_jdg2. If the determination in S60 is YES, in S70, regenerative braking by the second electric motor MG2 is permitted. After S50 is executed, if the determination in S60 is NO, or after S70 is executed, S20 is executed again.

[0027] According to this embodiment, during evacuation traveling in the MDE traveling mode, if the state of charge value SOC exceeds the regeneration prohibition determination value SOC_jdg1, regenerative braking by the second electric motor MG2 is prohibited, and if the state of charge value SOC is equal to or less than the regeneration permission determination value SOC_jdg2, regenerative braking by the second electric motor MG2 is permitted. During evacuation traveling, if the state of charge value SOC exceeds the regeneration prohibition determination value SOC_jdg1, the battery 40 is likely to become overcharged. By prohibiting regenerative braking by the second electric motor MG2, the battery 40 is less likely to become overcharged in this state than when regenerative braking by the second electric motor MG2 is permitted. During evacuation traveling, if the state of charge value SOC of the battery 40 is equal to or less than the regeneration permission determination value SOC_jdg2, the battery 40 is likely to become undercharged. Compared to when regenerative braking by the second electric motor MG2 is prohibited, when regenerative braking by the second electric motor MG2 is permitted, the battery 40 is less likely to become undercharged in such a state. In this way, the battery 40 is less likely to become overcharged and undercharged, which reduces the number of situations in which it becomes impossible to continue driving during evacuation driving.

[0028] The above-described embodiments of the present invention are merely examples, and the present invention can be embodied in various forms with various modifications and improvements based on the knowledge of those skilled in the art without departing from the spirit of the present invention.

[0029] In the above-described embodiment, the electronic control device 90 maintains a state in which regenerative braking by the second electric motor MG2 is permitted or prohibited when the state of charge value SOC is equal to or less than the regeneration prohibition determination value SOC_jdg1 and exceeds the regeneration permission determination value SOC_jdg2 during evacuation traveling in the MDE traveling mode. However, the present invention is not limited to this. For example, when the state of charge value SOC is equal to or less than the regeneration prohibition determination value SOC_jdg1 and exceeds the regeneration permission determination value SOC_jdg2, the electronic control device 90 may either prohibit or permit regenerative braking by the second electric motor MG2.

[0030] In the above-described embodiment, the regeneration prohibition determination value SOC_jdg1 is greater than the regeneration permission determination value SOC_jdg2, but this is not limiting. For example, the regeneration prohibition determination value SOC_jdg1 may be equal to the regeneration permission determination value SOC_jdg2.

[0031] In the above-described embodiment, the electronic control device 90 determines whether the state of charge value SOC is equal to or lower than the high charging determination value SOC_high and equal to or higher than the low charging determination value SOC_low, but may not necessarily make such a determination. [Explanation of symbols]

[0032] 10: vehicle, 12: engine, 30: first inverter, 32: second inverter, 40: battery, 50: DC / DC converter, 90: electronic control device (control device), MG1: first electric motor, MG2: second electric motor, SOC: state of charge value, SOC_jdg1: regeneration prohibition judgment value (predetermined first judgment value), SOC_jdg2: regeneration permission judgment value (predetermined second judgment value)

Claims

[Claim 1] A control device for a vehicle including an engine as a power source for running, a first electric motor formed by a permanent magnet type motor generator and rotated in a non-driven state while running using the engine as a power source, a second electric motor as a power source for running, a battery that supplies and receives electric power with the first electric motor via a first inverter and with the second electric motor via a second inverter, and a DC / DC converter provided between the first inverter and the battery, When the first electric motor is in a non-driving state and the vehicle is traveling using the engine and the second electric motor as a power source, if the state-of-charge value of the battery exceeds a predetermined first determination value, regenerative braking by the second electric motor is prohibited, and if the state-of-charge value of the battery is equal to or less than a predetermined second determination value, regenerative braking by the second electric motor is permitted. A vehicle control device comprising:

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