Hybrid vehicles

Abstract

Extends the driving range through vehicle maintenance control. [Solution] When the fuel level in the fuel tank falls below a lower limit, the control system initiates a driving maintenance control that disables the hybrid mode and executes the motor mode. If the State of Charge (SOC) of the energy storage device falls to a driving termination threshold while the driving maintenance control is being executed, the control system sets a driving failure flag and terminates the driving maintenance control. When the driving failure flag is set and the fuel level exceeds the lower limit due to refueling, and the driver performs a start operation to begin driving, the control system starts the engine and initiates the hybrid mode.

Description

Technical Field

[0001] The present disclosure relates to a hybrid vehicle.

Background Art

[0002] Hybrid vehicles equipped with an engine and a motor generator have been developed (see Patent Documents 1 to 3). As driving modes of a hybrid vehicle, there are a motor mode in which the engine is controlled to be in a stopped state and a hybrid mode in which the engine is controlled to be in an operating state.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, when the remaining fuel amount in the fuel tank falls below the lower limit value while the hybrid mode is being executed, the driving mode is switched from the hybrid mode to the motor mode. Further, the motor mode executed after fuel exhaustion continues until it becomes difficult to drive the motor generator, that is, until the SOC of the battery falls below a predetermined driving end threshold value. From the viewpoint of extending the driving distance in the motor mode executed after this fuel exhaustion, it is required to lower the driving end threshold value which is the end condition of the motor mode.

Means for Solving the Problems

[0005] According to this disclosure, a hybrid vehicle has a fuel tank connected to an engine via fuel lines and an energy storage device connected to a motor generator via power cables. The hybrid vehicle has a control system that controls the engine and the motor generator, comprising a processor and memory that are communicated with each other. There are two driving modes: a motor mode that controls the engine to a stopped state and a hybrid mode that controls the engine to an operating state. When the fuel level in the fuel tank falls below a lower limit, the control system initiates a driving maintenance control that disables the hybrid mode and executes the motor mode. If the State of Charge (SOC) of the energy storage device falls to a driving termination threshold while the driving maintenance control is being executed, the control system sets a driving failure flag and terminates the driving maintenance control. When the driving failure flag is set and the fuel level exceeds the lower limit due to refueling, and the driver performs a start operation to begin driving, the control system starts the engine and starts the hybrid mode. [Effects of the Invention]

[0006] According to this disclosure, the threshold for ending a drive can be lowered, and the driving distance can be extended by maintaining the driving control. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 shows a hybrid vehicle which is one embodiment of the present disclosure. [Figure 2] Figure 2 shows an example of a power unit. [Figure 3] Figure 3 shows an example of a control system for controlling a power unit. [Figure 4] Figure 4 shows an example of the basic structure of an electronic control unit. [Figure 5] Figure 5 is a map showing an example of the execution area for a driving mode. [Figure 6]Figure 6 is a flowchart showing an example of the procedure for performing vehicle maintenance control. [Figure 7] Figure 7 is a flowchart showing an example of the engine starting procedure after refueling. [Figure 8] Figure 8 is a timing chart showing an example of the execution status of the driving maintenance control and engine start. [Modes for carrying out the invention]

[0008] Embodiments of this disclosure will be described in detail below with reference to the drawings. In the following description, identical or substantially identical components and elements will be denoted by the same reference numerals, and repeated descriptions will be omitted.

[0009] <Power Unit> Figure 1 shows a hybrid vehicle 10, which is one embodiment of the present disclosure. As shown in Figure 1, the hybrid vehicle 10 has a power unit 12 consisting of an engine 11 and motor generators MG1 and MG2. The rear wheel output shaft 13 of the power unit 12 is connected to the rear wheels 16 via a propeller shaft 14 and a rear differential mechanism 15. The power unit 12 also includes a front differential mechanism 17, which is connected to the front wheels 18. The power unit 12 shown is a power unit for all-wheel drive, but is not limited to this, and may be a power unit for front-wheel drive or rear-wheel drive.

[0010] Figure 2 shows an example of a power unit 12. As shown in Figure 2, the power unit 12 has a main output shaft 20 that passes through the center of the motor generator MG2. The main output shaft 20 is connected to the front wheel output shaft 22 via a gear train 21 and to the rear wheel output shaft 13 via a transfer clutch 23. The main output shaft 20 is also connected to a power split mechanism 25 via a gear train 24. The power split mechanism 25 is connected to the rotor 26 of the motor generator MG1 and to the crankshaft 29 of the engine 11 via a gear train 27 and a damper mechanism 28. The main output shaft 20 is also connected to the rotor 31 of the motor generator MG2 via a planetary gear train 30. Furthermore, the front wheel output shaft 22 is connected to a front differential mechanism 17.

[0011] <Motor Generator and Battery Pack> Figure 3 shows an example of a control system 40 that controls the power unit 12. As shown in Figure 3, the stator 41 of the motor generator MG1 is connected to the switching circuit section 44 of the inverter 43 via a power cable 42. The switching circuit section 44 is connected to the battery pack 46 via a power cable 45. Similarly, the stator 47 of the motor generator MG2 is connected to the switching circuit section 49 of the inverter 43 via a power cable 48. The switching circuit section 49 is connected to the battery pack 46 via a power cable 45. Thus, the motor generator MG1 is connected to the battery pack (energy storage device) 46 via power cables 42 and 45, and the motor generator MG2 is connected to the battery pack 46 via power cables 48 and 45.

[0012] A motor control unit 50, which is an electronic control unit, is connected to the inverter 43, which performs the power supply control of the motor generators MG1 and MG2. The motor control unit 50 controls the motor torque of the motor generators MG1 and MG2 by controlling switching circuit sections 44 and 49, which consist of multiple switching elements. The motor torque of the motor generators MG1 and MG2 includes a power torque generated on the acceleration side when the motor generators MG1 and MG2 are controlled to the powering state, and a power generation torque generated on the deceleration side when the motor generators MG1 and MG2 are controlled to the power generation state.

[0013] The battery pack 46 includes a battery module 52 consisting of multiple battery cells 51, a main relay 53 that controls the connection state of the battery module 52, and a battery sensor 54 that detects the charge / discharge current and terminal voltage. An electronic control unit, the battery control unit 55, is connected to the battery pack 46. The battery control unit 55 outputs a control signal to the main relay 53, switching the main relay 53 to the ON or OFF state. The battery control unit 55 also calculates the State of Charge (SOC) of the battery pack 46 based on the charge / discharge current and terminal voltage detected by the battery sensor 54. The SOC of the battery pack 46 is a ratio indicating the remaining amount of electricity stored in the battery pack 46, and is the ratio of the amount of stored electricity to the full charge capacity of the battery pack 46.

[0014] <Engine and fuel tank> As shown in FIG. 3, the engine 11 has a throttle valve 60 for adjusting the intake air amount, an injector 61 for injecting fuel, and an ignition device 62 for igniting the air-fuel mixture. In order to control the operating state of the engine 11, an engine control unit 63, which is an electronic control unit, is connected to the throttle valve 60, the injector 61, and the ignition device 62. Further, the hybrid vehicle 10 includes a fuel tank 64 for storing fuel such as gasoline. A fuel pump 65 is housed in the fuel tank 64, and the injector 61 is connected to the fuel pump 65 via a fuel pipe 66. That is, the fuel tank 64 is connected to the engine 11 via the fuel pipe 66. Further, a level sensor 67 for detecting the remaining fuel amount is attached to the fuel tank 64, and a pressure sensor 68 for detecting the pressure of the fuel is attached to the fuel pipe 66.

[0015] <Control System> As shown in FIG. 3, the hybrid vehicle 10 has a control system 40 composed of a plurality of electronic control units. As the electronic control units constituting the control system 40, there are the motor control unit 50, the battery control unit 55, and the engine control unit 63 described above. Further, as an electronic control unit constituting the control system 40, there is a vehicle control unit 70 that outputs control signals to the above-described control units 50, 55, 63. These control units 50, 55, 63, 70 are communicably connected to each other via an in-vehicle network 71. The vehicle control unit 70 sets the operation target of the power unit 12 based on the input information from various control units 50, 55, 63 and various sensors described later. Further, the vehicle control unit 70 generates control signals corresponding to the operation target of the power unit 12, and outputs these control signals to the motor control unit 50, the engine control unit 63, etc.

[0016] As sensors connected to the vehicle control unit 70, there is an accelerator sensor 72 that detects the operation status of the accelerator pedal, and a brake sensor 73 that detects the operation status of the brake pedal. Also, as sensors connected to the vehicle control unit 70, there is a vehicle speed sensor 74 that detects the vehicle speed, which is the traveling speed of the vehicle 10, and an engine rotation sensor 75 that detects the rotation speed of the crankshaft 29. Further, as sensors connected to the vehicle control unit 70, there is a motor rotation sensor 76 that detects the rotation speed of the rotor 26 of the motor generator MG1, and a motor rotation sensor 77 that detects the rotation speed of the rotor 31 of the motor generator MG2.

[0017] Also, a fuel warning lamp 78a of the meter panel 78 is connected to the vehicle control unit 70, and a start switch 79 that is operated when switching the power mode of the control system 40 is connected. Note that as the power mode of the control system 40, there is an OFF mode that stops the functions of the control system 40, and an ON mode that starts the control system 40 and enables vehicle travel. For example, a driver carrying a key (not shown) gets into the vehicle, and by stepping on the brake pedal and pressing the start switch 79, the power mode is switched from the OFF mode to the ON mode. In this case, stepping on the brake pedal and pressing the start switch 79 becomes the start operation at the start of travel by the driver. Note that when the power mode is the OFF mode, the main relay 53 is controlled to be in the OFF state, while when the power mode is the ON mode, the main relay 53 is controlled to be in the ON state.

[0018] Figure 4 shows an example of the basic structure of the electronic control units 50, 55, 63, and 70. As shown in Figure 4, the electronic control units 50, 55, 63, and 70 have a microcontroller 82 that incorporates a processor 80 and a main memory (memory) 81, etc. A predetermined program is stored in the main memory 81, and the program is executed by the processor 80. The processor 80 and the main memory 81 are connected to each other so as to be able to communicate with each other. Note that the microcontroller 82 may incorporate multiple processors 80, and the microcontroller 82 may also incorporate multiple main memory 81.

[0019] The electronic control units 50, 55, 63, and 70 each include an input circuit 83, a drive circuit 84, a communication circuit 85, an external memory 86, and a power supply circuit 87. The input circuit 83 converts signals input from various sensors into signals that can be input to the microcontroller 82. The drive circuit 84 generates drive signals for devices such as the inverter 43, throttle valve 60, and injector 61 based on signals output from the microcontroller 82. The communication circuit 85 converts signals output from the microcontroller 82 into communication signals for other electronic control units, etc. The communication circuit 85 also converts communication signals received from other electronic control units, etc., into signals that can be input to the microcontroller 82. Furthermore, the power supply circuit 87 supplies power voltage to the microcontroller 82, input circuit 83, drive circuit 84, communication circuit 85, and external memory 86, etc. The external memory 86, which consists of non-volatile memory, stores programs and various data.

[0020] <Driving Mode> The hybrid vehicle 10 has two driving modes: a motor mode that controls the engine 11 to a stopped state, and a hybrid mode that controls the engine 11 to an operating state. Here, Figure 5 is a map showing an example of the execution area of ​​the driving mode. As shown in Figure 5, the map has a boundary line L1 that demarcates the execution area of ​​the motor mode and the hybrid mode. The requested driving force shown in Figure 5 is the driving force set based on the driver's accelerator operation. This requested driving force is set to be larger the more the driver presses the accelerator pedal, that is, the more the accelerator opening increases.

[0021] As shown by arrow A in Figure 5, when the requested driving force decreases or the vehicle speed decreases so that it falls below the boundary line L1 while the hybrid mode is running, the control system 40 switches the driving mode from hybrid mode to motor mode. On the other hand, as shown by arrow B in Figure 6, when the requested driving force increases or the vehicle speed increases so that it exceeds the boundary line L1 while the motor mode is running, the control system 40 switches the driving mode from motor mode to hybrid mode. When switching the driving mode from motor mode to hybrid mode, the motor generator MG1 is controlled to the powered state, thereby starting the rotation of the engine 11.

[0022] As indicated by the symbol α in Figure 5, the control system 40 selects and executes the motor mode as the driving mode when the required acceleration and vehicle speed are zero, that is, when the vehicle is stopped. Therefore, when the driver performs the start operation to begin driving, the control system 40 starts the motor mode without starting the engine 11, because the hybrid vehicle 10 is in the vehicle state indicated by the symbol α. The control system 40 also controls the motor generator MG1 to either a powering state or a power generation state depending on the driving state when executing the motor mode and hybrid mode. Similarly, the control system 40 controls the motor generator MG2 to either a powering state or a power generation state depending on the driving state when executing the motor mode and hybrid mode.

[0023] <Driving Maintenance Control> This section describes the vehicle maintenance control that is initiated when the vehicle runs out of fuel. Figure 6 is a flowchart showing an example of the procedure for executing the vehicle maintenance control. Each step in the flowchart in Figure 6 is executed by the processor 80 that constitutes the control system 40. The flowchart shown in Figure 6 is executed at predetermined intervals by the activated control system 40.

[0024] As shown in Figure 6, the control system 40 proceeds to step S10 and determines whether or not the fuel in the fuel tank 64 is depleted, based on the detection signal from the level sensor 67 installed in the fuel tank 64. In other words, the control system 40 determines that a fuel shortage has occurred when the amount of fuel remaining detected using the level sensor 67 falls below a predetermined lower limit. The control system 40 may also determine whether or not a fuel shortage has occurred by using a pressure sensor 68 that detects fuel pressure in addition to the level sensor 67 that detects the liquid level. In other words, the control system 40 may determine that a fuel shortage has occurred when the amount of fuel remaining detected by the level sensor 67 falls below a lower limit, and the fuel pressure detected by the pressure sensor 68 falls below a predetermined value.

[0025] If the control system 40 determines in step S10 that no fuel has been depleted, it proceeds to step S11 and switches the driving mode based on the driving conditions. In other words, the control system 40 selects and executes a driving mode from motor mode and hybrid mode based on the requested driving force and vehicle speed. On the other hand, if the control system 40 determines in step S10 that no fuel has been depleted, it proceeds to step S12 and illuminates the fuel warning light 78a on the meter panel 78 to notify the driver of the fuel depletion. Subsequently, since engine operation becomes impossible due to the fuel depletion, the control system 40 proceeds to step S13 and starts driving maintenance control, disabling hybrid mode and executing motor mode.

[0026] When the control system 40 starts maintaining operation due to fuel depletion, it proceeds to step S14 to determine whether the State of Charge (SOC) of the battery pack 46 is below a predetermined driving termination threshold S1. If the control system 40 determines in step S14 that the SOC is above the driving termination threshold S1, it returns to step S13 and continues the driving maintenance control, i.e., the motor mode. On the other hand, if the control system 40 determines in step S14 that the SOC is below the driving termination threshold S1, it proceeds to step S15 and terminates the driving maintenance control, i.e., the motor mode. Then, the control system 40 proceeds to step S16 to set the driving failure flag FL (FL=1), and proceeds to step S17 to switch the power mode to OFF mode. The situation in which the SOC is below the driving termination threshold S1, that is, the situation in which the SOC drops to the driving termination threshold S1, is the situation before the SOC reaches the discharge lower limit value SL, which is the discharge tolerance value of the battery pack 46.

[0027] Thus, when fuel runs out, the control system 40 starts driving maintenance control and forces the motor mode to be executed. This ensures that even in situations where engine operation becomes impossible due to fuel depletion, the minimum driving performance of the hybrid vehicle 10 can be secured. As mentioned above, the driving maintenance control after fuel depletion continues until the State of Charge (SOC) of the battery pack 46 reaches the driving termination threshold S1. For this reason, in order to secure the driving distance through the driving maintenance control after fuel depletion, it is important to set the driving termination threshold S1 close to the discharge limit value SL. Therefore, in the hybrid vehicle 10 of this disclosure, as will be described later, the engine 11 is started quickly after refueling to suppress the discharge of the battery pack 46, thereby lowering the driving termination threshold S1 to approach the discharge limit value SL, which is the discharge limit of the battery pack 46.

[0028] <Starting the engine after refueling> This section describes engine starting after refueling. Figure 7 is a flowchart showing an example of the engine starting procedure after refueling. The flowchart in Figure 7 is connected to the flowchart in Figure 6 at the points marked with the symbol A. Each step in the flowchart in Figure 7 is executed by the processor 80, which constitutes the control system 40. The flowchart in Figure 7 is executed when the control system 40 is started up.

[0029] As shown in Figure 7, the control system 40 proceeds to step S20 to determine whether the driver is pressing the brake pedal and the start switch 79, that is, whether the driver has performed the start operation to begin driving. If the control system 40 determines in step S20 that the start operation has been performed, it proceeds to step S21 to determine whether the immobility flag FL is set. If the control system 40 determines in step S21 that the immobility flag FL is not set, that is, if fuel has not run out or the driving maintenance control has not ended, it proceeds to step S10 in Figure 6. In other words, if fuel has not run out, it proceeds to step S11 and the driving mode is switched based on the driving state, and if fuel has run out, it proceeds to step S13 and the driving maintenance control continues.

[0030] As shown in Figure 7, if the control system 40 determines in step S21 that the inability to drive flag FL is set, that is, if it determines that the driving maintenance control has ended due to a decrease in SOC, it proceeds to step S22 to determine whether or not refueling has already been performed on the fuel tank 64. The control system 40 determines that refueling has been performed on the fuel tank 64 if the remaining fuel amount detected using the level sensor 67 exceeds a remaining amount threshold that is greater than the lower limit. Alternatively, the control system 40 may determine that refueling has been performed on the fuel tank 64 if the remaining fuel amount detected using the level sensor 67 exceeds the lower limit. The situations in which refueling is determined to have been performed in step S22 include situations in which refueling has been performed by towing the hybrid vehicle 10 to a gas station, or situations in which refueling has been performed on the fuel tank 64 from a portable fuel can that was brought to the scene.

[0031] If the control system 40 determines in step S22 that refueling has not been performed, that is, if it determines that the fuel shortage continues even after the end of the driving maintenance control, it proceeds to step S23, switches the power mode to OFF mode, and exits the routine. In other words, the situation in which it is determined in step S22 that refueling has not been performed is a situation in which it is impossible to drive the engine 11 and motor generators MG1 and MG2, so it proceeds to step S23, switches the power mode to OFF mode, and exits the routine.

[0032] On the other hand, if the control system 40 determines in step S22 that refueling is taking place, it proceeds to step S24 to turn off the fuel warning light 78a, and then proceeds to step S25 to clear the vehicle immobilization flag FL (FL=0). The control system 40 also proceeds to step S26 to control the motor generator MG1 to the powering state and starts the engine 11 using the motor generator MG1. After starting the engine 11 in step S26, the control system 40 proceeds to step S27 to control the motor generator MG1 to the power generation state and executes a hybrid mode in which the engine 11 drives the motor generator MG1 to generate electricity.

[0033] Next, the control system 40 proceeds to step S28 and determines whether the State of Charge (SOC) of the battery pack 46 exceeds a predetermined charge termination threshold S2. If the control system 40 determines in step S28 that the SOC is less than or equal to the charge termination threshold S2, it returns to step S27 and continues to drive the motor generator MG1 with the engine 11. On the other hand, if the control system 40 determines in step S28 that the SOC exceeds the charge termination threshold S2, it proceeds to step S29 and switches the driving mode based on the driving state.

[0034] As explained above, after the control system 40 starts driving maintenance control due to fuel depletion, when the State of Charge (SOC) of the battery pack 46 drops to the driving termination threshold S1, it sets the driving failure flag FL and terminates the driving maintenance control. Subsequently, when the driving failure flag FL is set and the remaining fuel level exceeds the lower limit due to refueling, and the driver performs the start operation to begin driving, the control system 40 starts the engine 11 and starts the hybrid mode.

[0035] Thus, after the driving maintenance control ends due to a decrease in SOC following fuel depletion, the control system 40 starts the engine 11 and enters hybrid mode when fuel is replenished in the fuel tank 64 and the driver performs a start operation. In other words, as shown by the symbol α in Figure 5, the situation in which the driver performs a start operation when starting to drive is a situation in which the motor mode would normally start without starting the engine 11. However, the control system 40 of this disclosure immediately enters hybrid mode when the start operation is performed. As a result, the motor mode is not executed again after the end of the driving maintenance control, and the discharge of the battery pack 46 can be kept to a minimum. Therefore, even if the driving termination threshold S1 is lowered to be close to the discharge lower limit value SL, it is possible to prevent the SOC of the battery pack 46 from falling below the discharge lower limit value SL. That is, since the driving termination threshold S1 can be lowered while suppressing over-discharge of the battery pack 46, the driving distance under driving maintenance control can be extended.

[0036] <Timing Chart> This section explains the vehicle maintenance control system in the event of fuel depletion, as well as the engine starting process after refueling. Figure 8 is a timing chart showing an example of the vehicle maintenance control and engine starting process.

[0037] As shown in Figure 8, at time t1, the remaining fuel level is above the lower limit Fa (symbol a1), and the hybrid mode is being executed as the driving mode (symbol b1). At time t2, the remaining fuel level falls below the lower limit Fa (symbol a2), and driving maintenance control is initiated, disabling the hybrid mode and executing the motor mode (symbols b2, c1). Subsequently, at time t3, the SOC of the battery pack 46 drops to the driving termination threshold S1 (symbol d1), so the driving maintenance control is stopped (symbol c2), the driving failure flag FL is set (symbol e1), and the power mode is switched to OFF mode (symbol f1).

[0038] Subsequently, at time t4, fuel is replenished to the fuel tank 64, and the remaining fuel level exceeds the remaining fuel threshold Fb (symbol a3). Then, at time t5, the driver performs the start operation when starting to drive, switching the power mode to ON mode (symbol f2), starting the engine 11, and executing the hybrid mode (symbol b3). In other words, the vehicle is in a state where the derailment flag FL is set (symbol e2), and the remaining fuel level exceeds the remaining fuel threshold Fb (symbol a4), and the driver performs the start operation when starting to drive, so the engine 11 starts and the hybrid mode is executed (symbol b3). Furthermore, the vehicle is in a state where the derailment flag FL is set (symbol e2), and the remaining fuel level exceeds the remaining fuel threshold Fb (symbol a4), and the driver performs the start operation when starting to drive, so the vehicle is then derailment flag FL is cleared (symbol e3).

[0039] As explained above, after the driving maintenance control ends due to a decrease in SOC following fuel depletion, the control system 40 starts the engine 11 and enters hybrid mode when fuel is replenished in the fuel tank 64 and the driver initiates a start operation. This prevents the motor mode from being executed again after the driving maintenance control ends, minimizing the discharge of the battery pack 46. For this reason, as shown in the enlarged portion of Figure 8, the difference between the discharge limit value SL and the driving termination threshold S1 can be set to be close to the power consumption ΔS at engine start. In other words, the driving termination threshold S1 can be set lower, thereby extending the driving distance under driving maintenance control. Note that the power consumption ΔS at engine start is the power consumption of the motor generator MG1 that cranks, i.e., starts, the engine 11.

[0040] <Variation> This disclosure is not limited to the embodiments described above, and it goes without saying that various modifications are possible without departing from the spirit of the invention. The illustrated power unit 12 is equipped with two motor generators MG1 and MG2, but is not limited to this, and may be a power unit equipped with one motor generator. Also, the illustrated hybrid vehicle 10 is a series-parallel hybrid vehicle, but is not limited to this, and may be a series hybrid vehicle.

[0041] In the flowchart shown in Figure 6, the driving maintenance control is terminated in step S15, and then the driving failure flag FL is set in step S16. However, this is not the only option, and the driving maintenance control may be terminated after setting the driving failure flag FL. In the above description, the starting operation when the driver starts driving is exemplified as pressing the start switch 79 while pressing the brake pedal, but this is not the only option, and other operations may be used. In the above description, gasoline is exemplified as the fuel, but this is not the only option, and diesel fuel, hydrogen, etc. may be used as the fuel. [Explanation of Symbols]

[0042] 10...Hybrid vehicle, 11...Engine, 40...Control system, 42,45...Power cable, 46...Battery pack (energy storage device), 64...Fuel tank, 66...Fuel piping, 80...Processor, 81...Main memory (memory), MG1...Motor generator, FL...Delivery failure flag, Fa...Lower limit, Fb...Remaining limit, S1...Driving end threshold

Claims

1. A hybrid vehicle equipped with an engine and a motor generator, A fuel tank connected to the engine via fuel lines, A power storage device connected to the motor generator via a power supply cable, A control system comprising a processor and memory connected to each other in a manner that enables communication, for controlling the engine and the motor generator, It has, The driving modes include a motor mode in which the engine is controlled to a stopped state, and a hybrid mode in which the engine is controlled to an operating state. The control system is When the fuel level in the fuel tank falls below the lower limit, the hybrid mode is disabled and the motor mode is activated to initiate a driving maintenance control. If the State of Control (SOC) of the energy storage device drops to the end-of-driving threshold during the execution of the aforementioned driving maintenance control, a driving failure flag is set and the driving maintenance control is terminated. When the aforementioned inoperable flag is set and the remaining fuel level exceeds the lower limit due to refueling, if the driver performs the start operation to begin driving, the engine will start and the hybrid mode will be activated. Hybrid vehicle.

2. In the hybrid vehicle described in claim 1, The control system starts and rotates the engine using the motor generator. Hybrid vehicle.

3. In the hybrid vehicle described in claim 1, The control system is When the aforementioned inoperable flag is not set, and the driver performs the start operation to begin driving, the motor mode is started without starting the engine. Hybrid vehicle.

4. In the hybrid vehicle described in claim 1, The control system is When the aforementioned inoperable flag is set and the remaining fuel level exceeds the lower limit due to refueling, if the driver performs the start operation to begin driving, the engine is started to activate the hybrid mode, and the engine drives the motor generator to generate electricity. Hybrid vehicle.

5. In the hybrid vehicle described in claim 1, The control system is When the aforementioned disabled flag is set and the remaining fuel level exceeds a threshold greater than the lower limit due to refueling, the engine starts and the hybrid mode is activated when the driver initiates the start of driving. Hybrid vehicle.

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