Vehicle control device

Abstract

To increase stop opportunity of an engine.SOLUTION: A control device for a vehicle is applied to a vehicle which is provided with an engine. It includes an engine control part which stops the engine on the basis of stop condition and starts the engine on the basis of start condition, an electric motor which starts and rotates the engine when starting the engine on the basis of the start condition, a power storage body which is connected to the electric motor, an SOC detection part which detects SOC of the power storage body, an internal resistance detection part which detects internal resistance of the power storage body, and a resistance threshold value setting part which sets resistance threshold value on the basis of the SOC. The engine control part prohibits stop of the engine on the basis of the stop condition (step S16, S12) if the internal resistance is greater than the resistance threshold value and on the other hand, permits stop of the engine on the basis of the stop condition (step S16, S17) if the internal resistance is smaller than the resistance threshold value.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a vehicle control device that is applied to a vehicle equipped with an engine. [Background technology]

[0002] Hybrid vehicles and idling stop vehicles are examples of vehicles that stop the engine based on a predetermined stop condition and start the engine based on a predetermined start condition (see Patent Documents 1 and 2). For example, in a hybrid vehicle, when the required driving force for the vehicle is small, the stop condition is met and the engine is stopped, whereas when the required driving force for the vehicle is large, the start condition is met and the engine is started. Also, in an idling stop vehicle, when the vehicle speed falls below a predetermined speed with the brake pedal depressed, the stop condition is met and the engine is stopped, whereas when the brake pedal is released or the accelerator pedal is depressed, the start condition is met and the engine is started. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-111456 A [Patent Document 2] JP 2019-160662 A Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, when the start conditions are met while the engine is stopped, the engine is started and rotated by the starter motor or the like, so it is necessary to supply sufficient power from the battery to the starter motor. For this reason, when the engine is stopped based on the stop conditions, it is necessary to increase the SOC (State of Charge) of the battery in preparation for the subsequent restart of the engine. However, allowing the engine to be stopped only when the battery SOC is in a high range reduces the opportunities to stop the engine.

[0005] An object of the present invention is to increase the chances of stopping the engine. [Means for solving the problem]

[0006] Books The invention one The vehicle control device according to the embodiment is a vehicle control device applied to a vehicle equipped with an engine, and includes an engine control unit that stops the engine based on a stop condition and starts the engine based on a start condition. The vehicle control device includes an electric motor that starts and rotates the engine when starting the engine based on the start condition. The vehicle control device includes a power storage device connected to the electric motor, a SOC detection unit that detects the SOC of the power storage device, an internal resistance detection unit that detects the internal resistance of the power storage device, and a resistance threshold setting unit that sets a resistance threshold based on the SOC. The resistance threshold setting unit sets the resistance threshold to a smaller value as the SOC decreases. The engine control unit includes: The SOC falls below a lower limit that allows engine shutdown, or When the internal resistance exceeds the resistance threshold, stopping of the engine based on the stop condition is prohibited. 。 on the other hand, The engine control unit detects whether the SOC exceeds the lower limit value, and When the internal resistance falls below the resistance threshold, the engine is permitted to be stopped based on the stop condition. Effect of the Invention

[0007] According to the present invention, the resistance threshold is set based on the SOC of the power storage unit, and when the internal resistance of the power storage unit exceeds the resistance threshold, stopping of the engine based on the stop condition is prohibited, whereas when the internal resistance of the power storage unit falls below the resistance threshold, stopping of the engine based on the stop condition is permitted, thereby increasing the opportunities for stopping the engine. [Brief description of the drawings]

[0008] [Figure 1] 1 is a schematic diagram showing a vehicle to which a vehicle control device according to an embodiment of the present invention is applied; [Diagram 2] 2 is a schematic diagram showing a configuration example of a control system provided in the vehicle control device; [Diagram 3] FIG. 1A is a diagram showing the execution status of the EV mode, and FIG. 1B is a diagram showing the execution status of the HEV mode. [Figure 4] 4 is a driving mode map showing an example of an execution region of an EV mode and an HEV mode. [Diagram 5] FIG. 2 is a simplified circuit diagram of an engine starting system. [Figure 6] 5 is a flowchart showing an example of an execution procedure of engine stop permission determination. [Figure 7] FIG. 13 is a diagram illustrating an example of a subtraction correction value. [Figure 8] FIG. 13 is a diagram illustrating an example of an EV permission threshold value. [Figure 9] FIG. 4 is a diagram showing an example of an engine stop permission region in which an EV permission flag is set. [Figure 10] 1 is a diagram illustrating an example of the relationship between SOC and a terminal voltage VB. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

[0010] [Powertrain] FIG. 1 is a schematic diagram showing a vehicle 11 to which a vehicle control device 10 according to an embodiment of the present invention is applied. As shown in FIG. 1, the vehicle 11 is equipped with a power train 14 having an engine 12 and a motor generator 13 as a power source. The power train 14 is provided with a continuously variable transmission 17 consisting of a primary pulley 15 and a secondary pulley 16. The engine 12 is connected to one end of a primary shaft 18 supporting the primary pulley 15 via an input clutch 19 and a torque converter 20. On the other hand, the motor generator 13 is connected to the other end of the primary shaft 18 supporting the primary pulley 15 via a rotor shaft 21. Furthermore, wheels 24 are connected to a secondary shaft 22 supporting the secondary pulley 16 via an output shaft 23 and the like.

[0011] [Starter generator and battery] A starter generator (electric motor) 32 is connected to a crankshaft 30 of the engine 12 via a belt mechanism 31. The starter generator 32 is a so-called ISG (Integrated Starter Generator) that functions as both a generator and an electric motor. In other words, the starter generator 32 not only functions as a generator that is rotationally driven by the crankshaft 30 to generate electricity, but also functions as an electric motor that rotationally drives the crankshaft 30. For example, when a predetermined starting condition is met to start the engine 12, the starter generator 32 that functions as an electric motor performs starting rotation of the engine 12.

[0012] The starter generator 32 has a stator 33 equipped with a stator coil, and a rotor 34 equipped with a field coil. The starter generator 32 is also provided with an ISG controller 35 including an inverter, a regulator, a microcomputer, and the like, in order to control the energization state of the stator coil and the field coil. Furthermore, a positive terminal 32a of the starter generator 32 is electrically connected to a positive terminal 37a of a battery (electricity storage body) 37 via a current line 36. Note that, for example, a lead battery or a lithium ion battery can be used as the battery 37.

[0013] In addition, the battery 37 is provided with a battery sensor 40, which has the function of detecting the charge / discharge current, terminal voltage, SOC, internal resistance, etc. of the battery 37. That is, the battery sensor 40 is provided with a current detection unit 41 which detects the charge / discharge current of the battery 37, a voltage detection unit 42 which detects the terminal voltage of the battery 37, a SOC detection unit 43 which detects the SOC of the battery 37, and an internal resistance detection unit 44 which detects the internal resistance of the battery 37.

[0014] The SOC (State of Charge) of the battery 37 is a ratio indicating the remaining amount of charge in the battery 37, and is the ratio of the amount of charge to the full charge capacity of the battery 37. The SOC detection unit 43 of the battery sensor 40 can calculate the SOC of the battery 37, for example, by estimating it from the terminal voltage of the battery 37 or by integrating the charge / discharge current of the battery 37. The internal resistance detection unit 44 of the battery sensor 40 can calculate the internal resistance of the battery 37, for example, by dividing the terminal voltage of the battery 37 by the charge / discharge current.

[0015] [Control system] Fig. 2 is a schematic diagram showing a configuration example of a control system 50 provided in the vehicle control device 10. As shown in Fig. 2, the vehicle control device 10 is provided with a plurality of controllers, each of which is made up of a microcomputer or the like, as the control system 50 that controls the powertrain 14. In addition to the ISG controller 35 described above, the controllers constituting the control system 50 include an engine controller 51 that controls the engine 12, a motor controller 52 that controls the motor generator 13, a mission controller 53 that controls the continuously variable transmission 17, the input clutch 19, etc., and a main controller 54 that controls the controllers 35, 51 to 53 in an integrated manner. These controllers 35, 51 to 54 are connected to each other via an in-vehicle network 55 such as CAN or LIN, so as to be able to communicate with each other.

[0016] Various sensors for detecting driving conditions and traveling conditions are connected to the main controller 54. These sensors include an accelerator sensor 60 for detecting the amount of depression of an accelerator pedal (hereinafter referred to as accelerator opening), a brake sensor 61 for detecting the amount of depression of a brake pedal, a vehicle speed sensor 62 for detecting the vehicle speed which is the traveling speed of the vehicle 11, and a battery sensor 40 for detecting the SOC and internal resistance of the battery 37. The main controller 54 also includes a traveling mode control unit 63 for selecting a traveling mode from the EV mode and the HEV mode and controlling the powertrain 14 according to the selected traveling mode.

[0017] [Driving mode] Fig. 3(A) is a diagram showing an execution state of the EV mode, and Fig. 3(B) is a diagram showing an execution state of the HEV mode. Vehicle 11 has, as driving modes, an EV mode in which engine 12 is stopped and motor generator 13 is driven, and an HEV mode in which engine 12 and motor generator 13 are driven.

[0018] As shown in FIG. 3(A), when the EV mode is executed as the driving mode, the driving mode control unit 63 of the main controller 54 controls the input clutch 19 to a released state, controls the engine 12 to a stopped state, and controls the motor generator 13 to a powering state or a regenerative state. This makes it possible to control the driving state of the vehicle 11 using the torque of the motor generator 13. On the other hand, as shown in FIG. 3(B), when the HEV mode is executed as the driving mode, the driving mode control unit 63 of the main controller 54 controls the input clutch 19 to an engaged state, controls the engine 12 to an operating state, and controls the motor generator 13 to a powering state or a regenerative state. This makes it possible to control the driving state of the vehicle 11 using the torque of the engine 12 and the motor generator 13.

[0019] Here, FIG. 4 is a driving mode map showing an example of an execution region of the EV mode and the HEV mode. As shown in FIG. 4, a mode threshold M1 is set in the driving mode map to divide the execution region of the EV mode and the HEV mode. As shown by an arrow A in FIG. 4, when the required driving force or the vehicle speed in the HEV mode decreases to fall below the mode threshold M1, the driving mode is switched from the HEV mode to the EV mode. That is, when the required driving force or the vehicle speed decreases to fall below the mode threshold M1, the engine 12 is stopped by establishing a predetermined stop condition. On the other hand, as shown by an arrow B in FIG. 4, when the required driving force or the vehicle speed in the EV mode increases to exceed the mode threshold M1, the driving mode is switched from the EV mode to the HEV mode. That is, when the required driving force or the vehicle speed increases to exceed the mode threshold M1, the engine 12 is started by establishing a predetermined start condition.

[0020] In this way, the driving mode control unit 63 of the main controller 54 selects and executes the EV mode or the HEV mode based on the required driving force and the vehicle speed. That is, the driving mode control unit (engine control unit) 63 of the main controller 54 stops the engine 12 based on a predetermined stop condition, and starts the engine 12 based on a predetermined start condition. The required driving force is set based on the accelerator opening, for example. That is, when the accelerator opening increases by depressing the accelerator pedal, the required driving force is set to be large, and when the accelerator opening decreases by releasing the accelerator pedal, the required driving force is set to be small.

[0021] [Engine stop permission decision (overview)] As described above, when the required driving force or the vehicle speed decreases below the mode threshold M1, the stop condition of the engine 12 is satisfied, so that the engine 12 is stopped and the driving mode is switched from the HEV mode to the EV mode. When the engine 12 is stopped according to the stop condition, it is necessary to increase the SOC of the battery 37 in preparation for restarting the engine when the start condition is satisfied later. In other words, if the engine 12 is stopped in a state where the SOC is low, the power supplied to the starter generator 32 is insufficient, making it difficult to restart the engine. Therefore, it has been necessary to prohibit stopping the engine when the SOC is low.

[0022] However, permitting engine stop only in the region where the SOC of the battery 37 is high is a factor that reduces the opportunities for stopping the engine 12. For this reason, the driving mode control unit 63 of the main controller 54 executes an engine stop permission determination described later to determine whether or not the power supply from the battery 37 to the starter generator 32 is sufficient, that is, whether or not the engine start performance of the starter generator 32 is ensured. Then, when it is determined that the engine start performance is ensured, the engine stop is permitted even if the SOC of the battery 37 decreases. This can increase the opportunities for stopping the engine 12, that is, the opportunities for executing the EV mode, as described later, and improve the fuel efficiency of the vehicle 11. In addition, in order to execute the engine stop permission determination, the main controller 54 is provided with a resistance threshold setting unit 64 that sets a resistance threshold based on the SOC.

[0023] [Engine starting performance] The engine starting performance of the starter generator 32 will be described. FIG. 5 is a circuit diagram simply showing the engine starting system. As shown in FIG. 5, the positive terminal 37a of the battery 37 and the positive terminal 32a of the starter generator 32 are connected via a current line 36, and the negative terminal 37b of the battery 37 and the negative terminal 32b of the starter generator 32 are connected via a current line 38. The terminal voltage of the battery 37 is "VB", the internal resistance of the battery 37 is "RB", the terminal voltage of the starter generator 32 is "Visg", and the internal resistance of the starter generator 32 is "Risg". The electric resistance of the current line 36 is "Rw1", the electric resistance of the current line 38 is "Rg1", and the current flowing from the battery 37 to the starter generator 32 is "Ip".

[0024] The engine starting performance of the starter generator 32 corresponds to the power consumption Wisg of the starter generator 32 at the time of engine starting. In other words, the larger the power consumption Wisg of the starter generator 32, the larger the kinetic energy output from the starter generator 32, and therefore the engine starting performance of the starter generator 32 is considered to be higher. The power consumption Wisg of the starter generator 32 is calculated by multiplying the terminal voltage Visg and the current Ip as shown in formula (1), so that the power consumption Wisg increases as the terminal voltage Visg increases, and the power consumption Wisg increases as the current Ip increases. Furthermore, as shown in formula (2), the terminal voltage Visg constituting formula (1) increases as the terminal voltage VB of the battery 37 increases, and increases as the internal resistance RB of the battery 37 decreases. Furthermore, as shown in formula (3), the current Ip constituting formula (1) increases as the terminal voltage VB of the battery 37 increases, and increases as the internal resistance RB of the battery 37 decreases. Wisg = Visg × Ip (1) Visg=VB-(RB+Rw1+Rg1)×Ip ···(2) Ip=VB / (RB+Rw1+Risg+Rg1) ···(3)

[0025] As shown in the above-mentioned formulas (1) to (3), the situation where the power consumption Wisg of the starter generator 32 increases is the situation where the terminal voltage VB of the battery 37 increases or the internal resistance RB of the battery 37 decreases. In other words, even if the terminal voltage VB of the battery 37 decreases, if the internal resistance RB of the battery 37 decreases, the power consumption Wisg required for engine start can be secured. Also, even if the internal resistance RB of the battery 37 increases, if the terminal voltage VB of the battery 37 increases, the power consumption Wisg required for engine start can be secured. For this reason, in order to determine whether the engine start performance is sufficient, it is important to appropriately determine the magnitude of the power consumption Wisg by using not only the SOC linked to the terminal voltage VB but also the internal resistance RB of the battery 37.

[0026] [Engine stop permission decision (flowchart)] The procedure for executing the engine stop permission determination will be described with reference to a flowchart. Fig. 6 is a flowchart showing an example of the procedure for executing the engine stop permission determination. Fig. 7 is a diagram showing an example of the subtraction correction value Rx, Fig. 8 is a diagram showing an example of the EV permission threshold value Rb1, and Fig. 9 is a diagram showing an example of the engine stop permission region in which the EV permission flag is set.

[0027] As shown in Fig. 6, in step S10, the SOC detected by the battery sensor 40 is read into the main controller 54. In the following step S11, it is determined whether the SOC of the battery 37 exceeds a predetermined lower limit value Smin. In step S11, if it is determined that the SOC of the battery 37 is equal to or lower than the lower limit value Smin, that is, if it is determined that the SOC of the battery 37 has significantly decreased, it is difficult to restart the engine using the starter generator 32, so the process proceeds to step S12, where an EV prohibition flag is set to prohibit engine stop. When this EV prohibition flag is set, engine stop based on a predetermined stop condition is prohibited, so switching from HEV mode to EV mode is prohibited.

[0028] On the other hand, if it is determined in step S11 that the SOC of the battery 37 exceeds the lower limit Smin, the process proceeds to step S13, where the subtraction correction value Rx is set based on the SOC. Here, as shown in FIG. 7, the subtraction correction value Rx is set to be smaller as the SOC increases. For example, when the SOC is "Smin", the subtraction correction value Rx is set to "X1", and when the SOC is "100%, the subtraction correction value Rx is set to "0". That is, when the SOC is low, that is, when the terminal voltage VB is low, the subtraction correction value Rx is set to be large, and when the SOC is high, that is, when the terminal voltage VB is high, the subtraction correction value Rx is set to be small.

[0029] In step S13, when the subtraction correction value Rx is set based on the SOC, the process proceeds to step S14, where an EV permission threshold (resistance threshold) Rb1 is calculated by subtracting the subtraction correction value Rx from a predetermined reference resistance value Rb0 as shown in the following formula (4). The reference resistance value Rb0 shown in formula (4) is the internal resistance of the battery 37 in a fully charged state, and is a resistance value that is set in advance by testing, simulation, or the like. Here, as shown in FIG. 8, the EV permission threshold Rb1 is calculated to be larger as the SOC increases. For example, when the SOC is "Smin", the EV permission threshold Rb1 is calculated as "Rb0-X1", and when the SOC is "100%", the EV permission threshold Rb1 is calculated as "Rb0". That is, when the SOC is low, that is, when the terminal voltage VB is low, the EV permission threshold Rb1 is calculated to be small, and when the SOC is high, that is, when the terminal voltage VB is high, the EV permission threshold Rb1 is calculated to be large. Rb1 = Rb0 - Rx (4)

[0030] In the next step S15, the internal resistance RB of the battery 37 detected by the battery sensor 40 is read into the main controller 54. Then, the process proceeds to step S16, where it is determined whether the internal resistance RB is below the EV permission threshold Rb1. If it is determined in step S16 that the internal resistance RB is below the EV permission threshold Rb1, the internal resistance RB is low, a large current can be output at engine start, and the power consumption Wisg required for engine start can be secured. Therefore, the process proceeds to step S17, where an EV permission flag is set to permit engine stop. If the EV permission flag is set, as shown by arrow A in FIG. 4, when a stop condition is established due to a decrease in the required driving force, etc., the engine 12 is controlled to a stopped state and the driving mode is switched to the EV mode.

[0031] On the other hand, if it is determined in step S16 that the internal resistance RB is equal to or greater than the EV permission threshold Rb1, the internal resistance RB is high and it is difficult to output a large current at engine start, and it is difficult to secure the power consumption Wisg required for engine start, so the process proceeds to step S12, where an EV prohibition flag is set to prohibit engine stop. When the EV prohibition flag is set, as shown by arrow A in Fig. 4, even if the stop condition is met due to a decrease in the required driving force, the driving mode is maintained in the HEV mode and the operating state of the engine 12 continues.

[0032] As shown in FIG. 8, the EV permission threshold Rb1 compared with the internal resistance RB is set to be smaller as the SOC of the battery 37 decreases. As a result, when the SOC is decreasing, the internal resistance RB required of the battery 37 can be reduced, and the power consumption Wisg required for engine start can be secured. That is, as shown by the symbol α in FIG. 9, even when the SOC of the battery 37 is low, that is, the terminal voltage VB of the battery 37 is low, in a region where the internal resistance RB of the battery 37 is smaller than the EV permission threshold Rb1, the current Ip of the starter generator 32 can be increased to secure the power consumption Wisg required for engine start, and engine stop based on a predetermined stop condition can be permitted. Note that the engine stop permission region shown by hatching in FIG. 9 is a region where the SOC exceeds the lower limit Smin and the internal resistance RB is below the EV permission threshold Rb1.

[0033] As described above, the EV permission threshold Rb1 is set based on the SOC of the battery 37, and when the internal resistance RB of the battery 37 exceeds the EV permission threshold Rb1, stopping of the engine 12 based on the stop condition is prohibited, whereas when the internal resistance RB of the battery 37 falls below the EV permission threshold Rb1, stopping of the engine 12 based on the stop condition is permitted. In other words, even in a situation where the SOC of the battery 37 is reduced, it is possible to permit stopping of the engine based on the stop condition while ensuring the power consumption Wisg required for engine start. This increases the opportunities for stopping the engine 12, thereby improving the fuel efficiency of the vehicle 11.

[0034] In the above description, the subtraction correction value Rx is set based on the SOC of the battery 37 by referring to the predetermined data shown in FIG. 7, but the present invention is not limited to this, and the subtraction correction value Rx may be calculated from the SOC of the battery 37. Here, FIG. 10 is a diagram showing an example of the relationship between the SOC and the terminal voltage VB. As shown in FIG. 10, when the terminal voltage VB is estimated from the SOC of the battery 37, the subtraction correction value Rx can be calculated based on the terminal voltage VB based on the following formula (5). Note that the terminal voltage Vb0 of the battery 37 shown in formula (5) is the terminal voltage of the battery 37 in a fully charged state, and is a voltage value that is set in advance by testing, simulation, or the like. In addition, the consumption current Iisg of the starter generator 32 is a current that flows from the battery 37 in a fully charged state to the starter generator 32 at the time of engine start, and is a current value that is set in advance by testing, simulation, or the like. In other words, since "Vb0" and "Iisg" included in formula (5) are fixed values, the subtraction correction value Rx can be calculated using the terminal voltage VB estimated from the SOC of the battery 37. Rx = (Vb0 - VB) / Iisg (5)

[0035] In the above description, the subtraction correction value Rx is set based on the SOC of the battery 37, and then the subtraction correction value Rx is subtracted from the reference resistance value Rb0 to set the EV permission threshold (resistance threshold) Rb1 based on the SOC, but this is not limiting. For example, the EV permission threshold Rb1 may be set directly from the SOC of the battery 37 by setting the EV permission threshold Rb1 for each SOC in advance through experiments, simulations, or the like. In the example shown in FIG. 8, the EV permission threshold Rb1 is changed along a straight line, but this is not limiting, and the EV permission threshold Rb1 may be changed along a curve. In the example shown in FIG. 8, the EV permission threshold Rb1 is changed continuously, but this is not limiting, and the EV permission threshold Rb1 may be changed in stages.

[0036] The present invention is not limited to the above embodiment, and can be modified in various ways without departing from the gist of the present invention. The vehicle to which the vehicle control device 10 according to the embodiment of the present invention is applied is not limited to the hybrid vehicle 11 equipped with the engine 12 and the motor generator 13 as a power source. For example, the present invention can be effectively applied to a vehicle equipped with only the engine 12 as a power source, as long as the vehicle has an idling stop function. In this case, the stop condition for stopping the engine 12 may be, for example, that the vehicle speed falls below a predetermined value and the brake pedal is depressed. Also, the start condition for starting the engine 12 may be, for example, that the brake pedal is released or that the accelerator pedal is depressed.

[0037] In the above description, the driving mode control unit 63 and the resistance threshold setting unit 64 are provided in the main controller 54, but the present invention is not limited to this, and the driving mode control unit 63 and the resistance threshold setting unit 64 may be provided in another controller. In the above description, the SOC detection unit 43 and the internal resistance detection unit 44 are provided in one battery sensor 40, but the present invention is not limited to this, and the SOC detection unit 43 and the internal resistance detection unit 44 may be provided separately in two sensors, or the SOC detection unit 43 and the internal resistance detection unit 44 may be provided in another controller. In the above description, the engine 12 is started using the starter generator 32, which is an ISG, but the present invention is not limited to this, and the engine 12 may be started using a starter motor, which is an electric motor. [Explanation of symbols]

[0038] 10 Vehicle control device 11 Vehicles 12 Engine 32 Starter generator (electric motor) 37 Battery (electricity storage unit) 43 SOC detector 44 Internal resistance detection section 63 Driving mode control unit (engine control unit) 64 Resistance threshold setting unit RB internal resistance Rb1 EV permission threshold (resistance threshold) Smin Lower limit

Claims

[Claim 1] A vehicle control device applied to a vehicle equipped with an engine, an engine control unit that stops the engine based on a stop condition and starts the engine based on a start condition; an electric motor that starts and rotates the engine when starting the engine based on the starting condition; a power storage unit connected to the electric motor; An SOC detection unit that detects an SOC of the power storage unit; an internal resistance detection unit that detects an internal resistance of the power storage unit; A resistance threshold setting unit that sets a resistance threshold based on the SOC; having The resistance threshold setting unit is The resistance threshold is set smaller as the SOC becomes lower, The engine control unit includes: When the SOC falls below a lower limit value that allows engine stop or when the internal resistance exceeds the resistance threshold, stopping of the engine based on the stop condition is prohibited; permitting a stop of the engine based on the stop condition when the SOC exceeds the lower limit value and the internal resistance falls below the resistance threshold value; Vehicle control device.

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