Hybrid vehicle

Abstract

Disclosed is a hybrid vehicle (1) comprising an engine (2), a motor (3) for driving the wheels and carrying out regenerative braking, a generator (4) for generating power by means of the driving force of the engine (2) and driving the engine (2), and a battery (5) connected to the motor (3) and the generator (4). In addition, this hybrid vehicle comprises a control device (10) for executing a regenerative motoring control wherein regenerative power of the motor (3) is supplied to the generator (4) and the engine (2) is motored at a prescribed target rotation speed during driving while the accelerator is off. The control device (10) stops regenerative motoring control when the accelerator is on during regenerative motoring control, and executes a first power generation control for causing the generator (4) to generate power while firing of the engine (2) is carried out, with the rotation speed of the engine fixed at the target rotation speed at that point in time.

Description

Technical Field

[0001] The present invention relates to a hybrid vehicle that performs regenerative motoring control.

Background Art

[0002] Conventionally, a hybrid vehicle has been known in which regenerative braking force is obtained by charging a battery with regenerative power generated in a driving motor. In this type of hybrid vehicle, when the charging of the battery is restricted (for example, when the battery is nearly fully charged or when the battery fails), there is a risk that the regenerative braking force cannot be obtained. Therefore, a control (regenerative motoring control) has been proposed in which regenerative power is consumed by a motor different from the driving motor to idle the engine, thereby balancing the power supply and demand. By such control, it is possible to secure the regenerative braking force while restricting the charging of the battery (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above-described regenerative motoring control, the rotational speed when idling the engine is set according to the magnitude of the regenerative power. On the other hand, when the accelerator pedal is depressed during the regenerative motoring control and regenerative power generation ends, if the starting condition of the engine is satisfied, the engine is controlled to self-rotate at a rotational speed according to the accelerator opening. As a result, there is a problem that the rotational speed of the engine fluctuates rapidly, which may give a sense of discomfort to the driver.

[0005] For example, when the engine rotational speed during engine motoring control is relatively high and the accelerator pedal is gently depressed, the engine rotational speed may rapidly decrease, and the engine noise and vibration may become extremely small. At this time, even though the driver is trying to accelerate the vehicle, they feel as if the engine has become quiet. Therefore, it feels to the driver that the operation of the vehicle does not match the actual behavior, and a good driving feeling cannot be obtained.

[0006] One of the objects of the present case is to provide a hybrid vehicle that has been devised in view of the above problems and can improve the driving feeling. Note that, not limited to this object, the effects derived from each configuration shown in the "Mode for Carrying Out the Invention" described later and that cannot be obtained by the conventional technology are also regarded as other objects of the present case.

Means for Solving the Problems

[0007] The disclosed hybrid vehicle can be realized as the aspects or application examples disclosed below and solves at least some of the above problems. The disclosed hybrid vehicle includes an engine, a motor that performs driving and regenerative braking of wheels, a generator that performs power generation by the driving force of the engine and drives the engine, and a battery connected to the motor and the generator. Further, it includes a control device that implements regenerative motoring control for supplying the regenerative power of the motor to the generator during running and when the accelerator is off to motor the engine at a predetermined target rotational speed. When the accelerator is turned on during the implementation of the regenerative motoring control, the control device stops the regenerative motoring control and shifts the operating state of the engine from the motoring state to the firing state, and while fixing the engine rotational speed at the target rotational speed at the time when the accelerator is turned on, performs the first power generation control for generating power in the generator while firing the engine.

Effects of the Invention

[0008] According to the disclosed hybrid vehicle, when the accelerator is turned on during the execution of regenerative motoring control, the regenerative motoring control is stopped and the first power generation control is executed. The first power generation control is a control in which while firing the engine while fixing the engine rotation speed at the target rotation speed at that time, power is generated by the generator. By executing such first power generation control, it is possible to suppress fluctuations in the engine rotation speed during the transition process from regenerative motoring control to the first power generation control, and it is possible to execute power generation of the generator without changing the noise and vibration of the engine. Therefore, the driving feeling during acceleration from regenerative motoring control can be improved.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0010] The disclosed hybrid vehicle can be implemented by the following embodiments.

Embodiment

[0011] [1. Device Configuration] 1 is a block diagram illustrating the configuration of a hybrid vehicle 1 according to an embodiment. This hybrid vehicle 1 (also simply referred to as vehicle 1) is a hybrid vehicle (HEV, Hybrid Electric Vehicle) or a plug-in hybrid vehicle (PHEV, Plug-in Hybrid Electric Vehicle) equipped with an engine 2 and a motor 3 as drive sources, a generator 4 as a power generation device, and a battery 5 as a power storage device. A plug-in hybrid vehicle refers to a hybrid vehicle in which the battery 5 can be externally charged or externally supplied with power from the battery 5. A plug-in hybrid vehicle is provided with a charging port (inlet) for inserting a charging cable through which power is supplied from an external charging facility, and a socket (outlet) for external power supply.

[0012] The engine 2 is an internal combustion engine such as a gasoline engine or a diesel engine. A generator 4 is coupled to the drive shaft of the engine 2. The generator 4 is a generator (electric motor / generator) that combines a function of driving the engine 2 with power from a battery 5 and a function of generating electricity using the driving force of the engine 2. The generated electricity of the generator 4 is used to drive the motor 3 and charge the battery 5. A speed change mechanism (not shown) may be provided on the power transmission path connecting the engine 2 and the generator 4.

[0013] The motor 3 is an electric motor (electric motor / generator) that has both the function of propelling the vehicle 1 using power from the battery 5 and the power generated by the generator 4, and the function of charging the battery 5 with power generated by regeneration. The battery 5 is, for example, a secondary battery such as a lithium-ion secondary battery or a nickel-metal hydride battery. The drive shaft of the motor 3 is connected to the drive wheels of the vehicle 1. A speed change mechanism (not shown) may be provided on the power transmission path connecting the motor 3 and the drive wheels.

[0014] A clutch 6 is interposed on the power transmission path connecting the engine 2 and the motor 3. The engine 2 is connected to the drive wheels via the clutch 6, and the motor 3 is arranged on the drive wheel side of the clutch 6. Further, the generator 4 is connected on the engine 2 side of the clutch 6. When the clutch 6 is disengaged (released), the engine 2 and the generator 4 are in a non-connected state with respect to the drive wheels, and the motor 3 is in a connected state with respect to the drive wheels. Therefore, for example, by operating only the motor 3, "EV driving (motor-only driving)" is realized. In addition to this, by operating the engine 2 to generate electricity in the generator 4, "series driving" is realized. Series driving means driving while generating electricity in the generator 4 with the driving force of the engine 2 and driving with the driving force of the motor 3.

[0015] On the other hand, when the clutch 6 is engaged (fastened), the three of the engine 2, the motor 3, and the generator 4 are in a connected state with respect to the drive wheels. Therefore, for example, by operating only the engine 2, "engine driving (engine-only driving)" is realized. In addition to this, by driving the motor 3 or the generator 4, "parallel driving" is realized. The above series driving and parallel driving are both also called "hybrid driving".

[0016] The operating states of the engine 2, the motor 3, the generator 4, the battery 5, and the clutch 6 are controlled by the control device 10. The control device 10 is a computer (electronic control unit, ECU, Electronic Control Unit) having a function of controlling at least the operating states of the engine 2 and the generator 4. The control device 10 incorporates a processor (arithmetic processing unit) and a memory (storage device). The content of the control (control program) implemented by the control device 10 is stored in the memory, and the content is executed by being appropriately read into the processor.

[0017] In the control device 10 of this embodiment, an accelerator opening sensor 7, a brake opening sensor 8, and a vehicle speed sensor 9 are connected. The accelerator opening sensor 7 is a sensor that detects a parameter (such as accelerator opening, accelerator pedal stroke, throttle opening, etc.) corresponding to the depression amount of the accelerator pedal. The brake opening sensor 8 is a sensor that detects a parameter (such as brake opening, brake pedal stroke, brake fluid pressure, etc.) corresponding to the depression amount of the brake pedal. The vehicle speed sensor 9 is a sensor that detects the traveling speed (vehicle speed) of the vehicle 1. The information detected by these sensors 7 to 9 is transmitted to the control device 10.

[0018] FIG. 2 is a graph illustrating a characteristic that defines the relationship between the accelerator opening [%] detected by the accelerator opening sensor 7 and the driver request output [kW] set by the control device 10. The accelerator opening is the depression amount of the accelerator pedal (for example, accelerator pedal stroke or rotation angle with respect to the fulcrum of the accelerator pedal, etc.) expressed as a percentage. Also, the driver request output is a parameter corresponding to the magnitude of the output (in other words, horsepower, electric power, work rate) requested by the driver to drive the vehicle 1. The driver request output is generally set to a larger value as the accelerator opening is larger. Note that the output of the drive source of the vehicle 1 is controlled so that it becomes a larger output as, for example, the driver request output or the vehicle speed is larger.

[0019] FIG. 3 is a graph illustrating the relationship between the vehicle speed [km / h] detected by the vehicle speed sensor 9 and the target rotational speed [rpm] of the engine 2. The solid line graph in FIG. 3 shows the characteristic during motoring of the engine 2 (when the vehicle 1 is decelerating), and the dashed line graph in FIG. 3 shows the characteristic during firing of the engine 2 (when the vehicle 1 is accelerating). Motoring means rotating the engine 2 idly using the generator 4 (rotating the engine 2 without burning the fuel-air mixture in the cylinder), and firing means self-rotating the engine 2 by supplying fuel and intake air to the engine 2 (burning the fuel-air mixture in the cylinder). Firing can be performed at least in a driving mode in which the engine 2 is operating, and can be performed, for example, during series driving.

[0020] When the vehicle is in motoring, the target engine speed of engine 2 is set to increase as the vehicle speed increases, as shown by the solid line graph in FIG. 3. However, in the high-speed region where the vehicle speed is equal to or higher than a predetermined vehicle speed, the target engine speed of engine 2 is fixed at a predetermined upper limit engine speed. Also, the target engine speed of engine 2 during firing is set to a value smaller than the target engine speed set during motoring for the same vehicle speed, as shown by the broken line graph in FIG. 3.

[0021] When strictly adhering to the setting of the target engine speed as shown in FIG. 3, when the state of engine 2 transitions from the motoring state to the firing state, the target engine speed will inevitably decrease, and the driving feeling may deteriorate. For example, when the accelerator pedal is depressed during regenerative motoring control and engine 2 enters the firing state, the rotational speed of engine 2 (engine speed) suddenly decreases, giving the driver a sense of discomfort. Considering such problems, the control device 10 of this embodiment performs a setting of the target engine speed different from the characteristics of the broken line graph in FIG. 3 when the accelerator is turned on (the accelerator opening exceeds a predetermined opening) during the execution of regenerative motoring control.

[0022] [2. Control Configuration] The control device 10 performs at least regenerative motoring control and first power generation control. Preferably, in addition to these controls, second power generation control is performed. Regenerative motoring control is a control in which, while the vehicle is running and the accelerator is off (the accelerator opening is equal to or less than a predetermined opening, the driver required torque or driver required output is equal to or less than a threshold value), the regenerative power of motor 3 is supplied to generator 4, and engine 2 is motored (idled) at a predetermined target engine speed. The implementation conditions of regenerative motoring control include at least that the vehicle 1 is running and the accelerator is off. In addition to this, conditions such as the charge rate of battery 5, the presence or absence of battery failure, the battery temperature, the brake opening, the braking force required for vehicle 1, the operating state of a friction brake device (not shown), and the road surface condition may be included in the implementation conditions of regenerative motoring control.

[0023] The first power generation control is a control that is implemented instead of the regenerative motor control when the accelerator is turned on during the execution of the regenerative motor control. It is a control that causes the generator 4 to generate electricity while firing the engine 2 while fixing the rotational speed of the engine 2 to the target rotational speed at that time (the time when the accelerator is turned on). In other words, the first power generation control is a control that maintains the target rotational speed at that time while suspending the setting of the target rotational speed based on the broken-line graph in FIG. 3 when the accelerator is turned on during the execution of the regenerative motor control. Thereby, sudden changes in the noise and vibration of the engine 2 before and after the accelerator is turned on are suppressed, and the driving feeling is improved.

[0024] In the first power generation control, the larger the accelerator opening (or the driver required output corresponding thereto), the larger the torque of the engine 2 can be set. On the other hand, since the target rotational speed is fixed, the actual rotational speed of the engine 2 is maintained. The rotational speed of the engine 2 can be changed by adjusting the load of the generator 4 on the engine 2 (the power that the generator 4 converts into electric power). Thus, the control device 10 can function to maintain the rotational speed of the engine 2 while increasing the torque of the engine 2 as the accelerator opening increases during the first power generation control.

[0025] The end condition of the first power generation control includes at least that the accelerator is off (the accelerator opening is less than or equal to a predetermined opening). When this condition is satisfied, the control device 10 can end the first power generation control and resume the regenerative motor control. Also, the end condition of the first power generation control in this embodiment includes that the driver required output exceeds a predetermined value. When this condition is satisfied, the control device 10 ends the first power generation control and implements the second power generation control.

[0026] The second power generation control is a control that, when the driver's required output exceeds a predetermined value (or when the accelerator opening exceeds a predetermined opening) during the first power generation control, stops the first power generation control and increases the rotational speed of engine 2. In other words, the second power generation control is a control that resumes setting the target rotational speed based on the broken-line graph in FIG. 3 when the driver deeply depresses the accelerator pedal. As a result, as the accelerator opening increases, the noise and vibration of engine 2 increase, and a natural and intuitive driving feeling that is easy to understand is realized. Note that the end condition of the second power generation control includes at least the accelerator being off. When this condition is satisfied, the control device 10 can end the second power generation control and resume the regenerative motorling control.

[0027] [3. Flowchart] FIG. 4 is a flowchart illustrating the flow of the first power generation control and the second power generation control. The control shown in this flowchart is repeatedly executed at a predetermined cycle inside the control device 10 when, for example, the power switch of a vehicle 1 (not shown) is on and the vehicle is drivable (in the READY state). Steps A1 to A3 mainly correspond to the regenerative motorling control, steps A4 to A8 mainly correspond to the first power generation control, and step A9 corresponds to the second power generation control.

[0028] In step A1, it is determined whether the execution condition of the regenerative motorling control is satisfied. If this condition is satisfied, the control proceeds to step A2. On the other hand, if the condition in step A1 is not satisfied, the control for this cycle ends. In step A2, based on characteristics such as the solid-line graph in FIG. 3, the target rotational speed of engine 2 is set according to the vehicle speed. Here, the higher the vehicle speed, the higher the target rotational speed of engine 2 is set. That is, since the higher the vehicle speed, the greater the regenerative power generated by motor 3, the target rotational speed of engine 2 driven by generator 4 is set high in order to consume power of a magnitude corresponding to that regenerative power by generator 4.

[0029] In step A3, regenerative motor control is performed based on the target rotational speed set in step A2. That is, the regenerative power of motor 3 is supplied to generator 4, and the generator 4 motors (idles) the engine 2 so that the rotational speed of the engine 2 becomes the target rotational speed. In step A4, it is determined whether or not the accelerator is on. Here, if it is determined that the accelerator is not on, the control for this cycle ends. From the next cycle onward, the regenerative motor control is continued as long as the execution condition of the regenerative motor control is satisfied. On the other hand, if it is determined in step A4 that the accelerator is on, the control proceeds to step A5.

[0030] In step A5, based on characteristics such as those shown in FIG. 2 for example, a driver required output is calculated based on the accelerator opening. The larger the accelerator opening, the larger the value set for the driver required output. In the subsequent step A6, it is determined whether or not the driver required output calculated in step A5 is less than or equal to a predetermined value. If this condition is satisfied, the control proceeds to step A7.

[0031] In step A7, while fixing the rotational speed of the engine 2 at the target rotational speed at that time, first power generation control is performed to generate power in the generator 4 while firing the engine 2. As a result, the operating state of the engine 2 shifts from the motoring state to the firing state. The torque of the engine 2 is set according to the driver required output. On the other hand, the target rotational speed of the engine 2 in the firing state is maintained at the same speed as the target rotational speed of the engine 2 in the motoring state. Therefore, the noise and vibration of the engine 2 hardly change, and the driving feeling is improved.

[0032] In the subsequent step A8, it is determined whether the accelerator is off. Here, if it is determined that the accelerator is not off, the control returns to step A5, and the driver demand output is calculated again. Thereafter, as long as the driver demand output is below a predetermined value, the first power generation control continues. Also, in step A8, if it is determined that the accelerator is off, the control for this cycle ends. After the next cycle, the regenerative motor modeling control is restarted as long as the conditions for implementing the regenerative motor modeling control are satisfied.

[0033] If it is determined in step A6 that the driver demand output exceeds a predetermined value, the control proceeds to step A9. In step A9, the second power generation control is implemented instead of the first power generation control, and the rotational speed of engine 2 is changed to a rotational speed higher than the target rotational speed at that time. The torque of engine 2 is set according to the driver demand output. During the second power generation control, the output of engine 2 becomes larger compared to during the first power generation control, and the generated power at generator 4 also increases.

[0034] In the subsequent step A8, it is determined whether the accelerator is off. Here, if it is determined that the accelerator is not off, the control returns to step A5, and the driver demand output is calculated again. Thereafter, as long as the driver demand output exceeds a predetermined value, the second power generation control continues. Also, in step A8, if it is determined that the accelerator is off, the control for this cycle ends. After the next cycle, the regenerative motor modeling control is restarted as long as the conditions for implementing the regenerative motor modeling control are satisfied.

[0035] [4. Operation] FIG. 5 is a time chart illustrating the operations of the first power generation control and the second power generation control. Here, it is assumed that the regenerative motor control is being implemented before time t1 and the accelerator is off. When the accelerator pedal is slightly depressed at time t1 to turn on the accelerator, the regenerative motor control stops and the first power generation control starts. The state of the engine 2 changes from the motoring state to the firing state at time t1. On the other hand, in the first power generation control, the target rotational speed of the engine 2 is maintained at the target rotational speed before time t1, and the actual rotational speed of the engine 2 also becomes a constant value. Therefore, the noise and vibration of the engine 2 hardly change, and the driving feeling is improved.

[0036] Note that if the first power generation control is not implemented, the target rotational speed of the engine 2 can be set relatively low at time t1, so the actual rotational speed of the engine 2 will decrease as shown by the dashed line in FIG. 5. However, in this embodiment, since the first power generation control is implemented, the rotational speed of the engine 2 hardly changes and remains constant before and after time t1. Also, if the first power generation control is not implemented, as shown by the two-dot chain line in FIG. 5, the torque of the engine 2 can become a slightly larger value.

[0037] On the other hand, in this embodiment, since the rotational speed of the engine 2 is higher than when the first power generation control is not implemented, the value of the torque for the same output (work rate) becomes smaller. Therefore, by reducing the torque by the amount by which the rotational speed of the engine 2 has increased compared to the case where the first power generation control is not implemented (in other words, so that the product of the rotational speed and the torque is constant), it is possible to maintain the rotational speed of the engine 2 without changing the generated power of the generator 4. Also, the output of the battery 5 (the power taken out from the battery 5) is the magnitude obtained by subtracting the generated power of the generator 4 from the power consumption of the motor 3 and various auxiliary devices.

[0038] When the accelerator pedal is released at time t2 and the engine goes off, the first power generation control stops and the regenerative motor control resumes. The state of engine 2 changes from the firing state to the motoring state with time t2 as the boundary. On the other hand, after time t2, the target rotational speed of engine 2 is kept constant, and the actual rotational speed also becomes a constant value. Therefore, the noise and vibration of engine 2 hardly change, and the driving feeling is improved.

[0039] When the accelerator pedal is depressed again at time t3 and the engine goes on, the regenerative motor control stops and the first power generation control resumes. The state of engine 2 changes from the motoring state to the firing state with time t3 as the boundary. On the other hand, after time t3, the target rotational speed of engine 2 is kept constant, and the actual rotational speed also becomes a constant value. Therefore, the noise and vibration of engine 2 hardly change, and the driving feeling is improved.

[0040] When the accelerator pedal is further depressed at time t4, the torque of engine 2 is set to be larger as the accelerator opening is larger. On the other hand, since the target rotational speed of engine 2 is kept constant after time t4, the output of engine 2 (the product of the rotational speed and the torque) increases as the torque increases, and the generated power of generator 4 also gradually increases. After that, when the driver required output exceeds a predetermined value at time t5, the second power generation control is implemented instead of the first power generation control. In the second power generation control, the setting of the target rotational speed based on the broken line graph in FIG. 3 resumes. As a result, the rotational speed of engine 2 increases, and the torque of engine 2 and the generated power of generator 4 also further increase. Therefore, as the accelerator opening is increased, the noise and vibration of engine 2 become larger, and a natural and intuitive driving feeling that is easy to understand is realized.

[0041] FIG. 6 is a graph illustrating the output characteristics (relationship between rotational speed and torque) of the engine 2. The thick solid line in FIG. 6 indicates the relationship between the rotational speed of the engine 2 and the maximum torque. The thin solid line in FIG. 6 is a curve connecting the operating points at which the same thermal efficiency (fuel consumption) is obtained at regular thermal efficiency intervals, and is an isocurve for the level of thermal efficiency. The operating point P0 in FIG. 6 is the operating point of the engine 2 when the first power generation control is not performed at times t1 to t2 and times t3 to t4 in FIG. 5, and the operating point P1 is the operating point of the engine 2 when the first power generation control is performed at times t1 to t2 and times t3 to t4 in FIG. 5.

[0042] The operating point P1 is set such that the output (product of rotational speed and torque) at the operating point P1 is the same as the output at the operating point P0. Therefore, it is not necessary to change the generated power of the generator 4 between when the first power generation control is performed and when it is not performed. Also, the operating point P1 has a slightly lower thermal efficiency compared to the operating point P0. From this, it can be seen that performing the first power generation control is slightly disadvantageous in terms of fuel consumption compared to not performing the first power generation control.

[0043] Also, the operating point P2 in FIG. 6 is the operating point of the engine 2 when the torque is increased while keeping the rotational speed of the engine 2 fixed at times t4 to t5 in FIG. 5, and the operating point P3 is the operating point of the engine 2 in the second power generation control after time t5 in FIG. 5, and is, for example, an operating point located near the maximum torque of the engine 2. The operating point P2 has a slightly higher thermal efficiency compared to the operating point P1. From this, it can be seen that in the first power generation control, the demerit in terms of fuel consumption decreases as the accelerator opening is increased. Also, since the operating point P3 is located upper right of the operating point P2 in FIG. 6, it can be seen that the output (product of rotational speed and torque) has increased.

[0044] [5. Effects] (1) The hybrid vehicle 1 of this embodiment includes an engine 2, a motor 3 that drives the wheels and performs regenerative braking, a generator 4 that generates electricity by the driving force of the engine 2 and drives the engine 2, and a battery 5 connected to the motor 3 and the generator 4. Further, it includes a control device 10 that implements regenerative motoring control for supplying the regenerative power of the motor 3 to the generator 4 and motoring the engine 2 at a predetermined target rotational speed while the vehicle is running and the accelerator is off. When the accelerator is turned on during the implementation of the regenerative motoring control, the control device 10 stops the regenerative motoring control and implements first power generation control. The first power generation control is a control for generating electricity in the generator 4 while firing the engine 2 while fixing the rotational speed of the engine 2 at the target rotational speed at that time.

[0045] By implementing such control, it is possible to suppress fluctuations in the rotational speed of the engine 2 during the transition process from regenerative motoring control to first power generation control. That is, when shifting from the motoring state to the firing state, the target rotational speed of the engine 2 in the firing state can be made the same as the target rotational speed of the engine 2 in the motoring state, and changes in the noise and vibration of the engine 2 can be suppressed. Therefore, the driving feeling during acceleration from regenerative motoring control can be improved.

[0046] Note that the initial value of the torque of the engine 2 in the first power generation control (torque T1 at the operating point P1 in FIG. 6) is set so that the output at the operating point P1 is the same as the output at the operating point P0. With such a setting, the output of the engine 2 can be made the same as the existing control, and the generated power of the generator 4 can also be made the same.

[0047] (2) When performing the first power generation control, the above control device 10 can implement control to maintain the rotational speed of the engine 2 while increasing the torque of the engine 2 as the accelerator opening increases. For example, the driver required output is set based on characteristics as shown in FIG. 2, and the torque of the engine 2 is controlled based on this driver required output. By such control, while increasing the output of the engine 2, changes in the noise and vibration of the engine 2 can be suppressed, and the driving feeling during acceleration from the regenerative motor control can be improved. Also, by increasing the output of the engine 2, the power generation amount of the generator 4 can be increased. Therefore, the power for driving the motor 3 can be increased, and a good acceleration feeling can be realized.

[0048] (3) When performing the first power generation control, the above control device 10 can implement second power generation control to stop the first power generation control and increase the rotational speed of the engine 2 when the driver required output exceeds a predetermined value. For example, as after the time t5 in FIG. 5, when the driver required output increases, by increasing the rotational speed of the engine 2 within a range equal to or higher than the target rotational speed, a behavior of the engine 2 without a sense of incongruity can be realized, and the driving feeling can be improved. Also, the power generation power of the generator 4 can be increased to improve the acceleration performance of the vehicle 1 and improve the driving feeling.

[0049] (4) When the accelerator is turned off during the implementation of the first power generation control, the above control device 10 can resume the regenerative motor control. By such control, when shifting from the firing state to the motoring state, the regenerative motor control can be resumed without changing the noise and vibration of the engine 2. Therefore, the driving feeling after the first power generation control can be improved.

[0050] [6. Others] The above embodiments are merely illustrative, and there is no intention to exclude various modifications and applications of technologies not explicitly described in this embodiment. Each configuration of this embodiment can be implemented with various modifications without departing from the gist thereof. Further, each configuration of this embodiment can be selected as appropriate, or can be combined as appropriate.

[0051] For example, in the above embodiment, the control device 10 that performs the regeneration motor control, the first power generation control, and the second power generation control is illustrated, but the second power generation control can be omitted. Further, in the above embodiment, when the accelerator is turned off during the execution of the first power generation control, the regeneration motor control is restarted, but such control is not essential. Also, the torque of the engine 2 in the first power generation control may be set according to the accelerator opening, may be set based on other parameters, or may be a preset fixed value. At least, by shifting the regeneration motor control to the first power generation control while fixing the rotational speed of the engine 2 at the target rotational speed at that time, the same operational effects as those of the above embodiment can be obtained.

Industrial Applicability

[0052] This case is applicable to the manufacturing industry of hybrid vehicles and is also applicable to the manufacturing industry of control devices for hybrid vehicles.

Explanation of Reference Numerals

[0053] 1 Vehicle (Hybrid Vehicle) 2 Engine 3 Motor 4 Generator 5 Battery 6 Clutch 7 Accelerator Opening Sensor 8 Brake Opening Sensor 9 Vehicle Speed Sensor 10 Control Device

Claims

1. An engine, a motor that drives and performs regenerative braking on the wheels, a generator that generates electricity by the driving force of the engine and drives the engine, a battery connected to the motor and the generator, and a control device that implements regenerative motoring control for supplying the regenerative power of the motor to the generator and motoring the engine at a predetermined target rotational speed while the vehicle is running and the accelerator is off. When the accelerator is turned on during the implementation of the regenerative motoring control, the control device stops the regenerative motoring control and shifts the operating state of the engine from the motoring state to the firing state, and while firing the engine while fixing the engine rotational speed at the target rotational speed at the time when the accelerator is turned on, the control device implements first power generation control for generating electricity in the generator. A hybrid vehicle, characterized in that.

2. During the first power generation control, the control device increases the torque of the engine while maintaining the engine rotational speed as the accelerator opening degree increases. The hybrid vehicle according to Claim 1, characterized in that.

3. During the first power generation control, when the driver required output exceeds a predetermined value, the control device stops the first power generation control and implements second power generation control for increasing the engine rotational speed. The hybrid vehicle according to Claim 1 or 2, characterized in that.

4. When the accelerator is turned off during the implementation of the first power generation control, the control device resumes the regenerative motoring control and shifts the operating state of the engine from the firing state to the motoring state. The hybrid vehicle according to any one of Claims 1 to 3, characterized in that.

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