阅读说明：本技术 混合动力车辆的控制装置 (Control device for hybrid vehicle ) 是由 桥本俊哉 加藤直人 角冈卓 吉永雅智 渡边大士 于 2019-08-23 设计创作，主要内容包括：本发明提供一种混合动力车辆的控制装置,其即使在驱动轮速度急剧减小的情况下,也能够抑制电池的过度充电。所述混合动力车辆的控制装置具备发动机、由发动机驱动的发电机、被供给电力而输出驱动转矩的驱动用电动机、以及能够充入产生的电力的蓄电装置,并且构成为将所述产生的电力向蓄电装置充电或者直接供给到驱动用电动机,在所述混合动力车辆的控制装置中,具备控制发电机的控制器,控制器判断驱动轮是否有可能抱死(步骤S2),在判断为驱动轮有可能抱死的情况下,将通过发电机产生的电力控制在能够输入到所述蓄电装置的预先确定的规定的电力以下(步骤S3)。(The invention provides a control device for a hybrid vehicle, which can restrain the overcharge of a battery even if the speed of a driving wheel is reduced rapidly. The control device for a hybrid vehicle includes an engine, a generator driven by the engine, a driving motor to which electric power is supplied to output driving torque, and a power storage device capable of charging generated electric power, and is configured to charge the power storage device with the generated electric power or directly supply the generated electric power to the driving motor, and the control device for a hybrid vehicle includes a controller that controls the generator, and the controller determines whether or not there is a possibility of locking of a driving wheel (step S2), and controls the electric power generated by the generator to be equal to or less than predetermined electric power that can be input to the power storage device when it is determined that there is a possibility of locking of the driving wheel (step S3).)

1. A control device for a hybrid vehicle is provided with: an engine; a generator driven by the engine; a drive motor that is coupled to a drive wheel and supplied with electric power to output a drive torque for traveling; and a power storage device capable of charging electric power generated by the generator, the control device of the hybrid vehicle being configured to charge the generated electric power to the power storage device or directly supply the generated electric power to the driving motor,

the generator is provided with a controller for controlling the generator,

the controller is configured to control the operation of the motor,

it is judged whether or not there is a possibility of locking the drive wheel,

when it is determined that there is a possibility of locking the drive wheels, the electric power generated by the generator is controlled to be equal to or less than a predetermined electric power that can be input to the power storage device.

2. The control device of a hybrid vehicle according to claim 1,

comprises a control system for controlling the posture and the motion of the vehicle,

the controller is configured to control the operation of the motor,

and determining whether or not the drive wheel is likely to be locked when there is an abnormality in a control signal of a sensor related to the control system.

3. The control device of a hybrid vehicle according to claim 1 or 2,

comprises a control system for controlling the posture and the motion of the vehicle,

the controller is configured to control the operation of the motor,

further determining whether the control system is off in a case where it is determined that locking of the drive wheels is not possible,

when the control system is turned off, the electric power generated by the generator is controlled to be equal to or less than an upper limit value obtained from the predetermined electric power that can be input to the power storage device and the consumed electric power based on the vehicle speed.

4. The control device of a hybrid vehicle according to claim 3,

the controller is configured to control the operation of the motor,

when the control system is on, the electric power generated by the generator is controlled to be equal to or less than an upper limit value obtained from the predetermined electric power that can be input to the power storage device and the consumed electric power based on the wheel speed of the drive wheel.

5. The control device of a hybrid vehicle according to any one of claims 1 to 4,

the hybrid vehicle is a series hybrid vehicle,

the series hybrid vehicle drives the generator by power of the engine to generate electric power, and the drive motor transmits the drive torque for running to the drive wheels based on electric power generated by the electric power generation to run.

6. The control device of a hybrid vehicle according to any one of claims 1 to 4,

the hybrid vehicle is a hybrid vehicle capable of selecting a series HV travel mode in which the generator is driven by power of the engine to generate electric power and the driving motor transmits the driving torque for travel to the drive wheels based on the electric power generated by the electric power generation to travel, and a parallel HV travel mode in which the torque of the engine and the driving torque of the driving motor are transmitted to the drive wheels to travel,

the controller is configured to control the operation of the motor,

further determining whether warming up of the engine is completed or not when it is determined that there is a possibility of locking of the drive wheels during running in the series HV running mode,

when it is determined that warm-up of the engine is completed, the travel mode is switched from the series HV travel mode to the parallel HV travel mode.

Technical Field

The present invention relates to a hybrid vehicle equipped with an engine and an electric motor having a power generation function as power sources, and more particularly to a control device for a hybrid vehicle configured to drive a generator (or an electric motor having a power generation function) by the engine to generate electric power.

Background

Patent document 1 describes a hybrid vehicle including an engine, a generator, a driving motor, and a battery. The vehicle described in patent document 1 is a so-called series hybrid vehicle, and is configured such that a generator is driven by an engine, and electric power generated by the generator is stored in a battery or supplied to a driving motor. In the vehicle described in patent document 1, when the chargeable and dischargeable electric power of the battery is limited due to, for example, a decrease in the temperature of the battery, the electric power is generated by the generator in accordance with the required driving force, and the generated electric power is consumed as the driving power without much or little change. In patent document 1, this control is referred to as direct power distribution control.

Further, when a traction control (traction control) is executed during the execution of the direct distribution control at the time of a wheel slip, the power generated due to a response delay (or a first order delay) of the engine is deviated, and it is configured to suppress the expected traction and to suppress the overcharge of the battery. More specifically, a parameter of the control time constant is set in consideration of the response delay of the engine, and the parameter is applied in the control of the servo system for controlling the speed of the drive wheel. That is, when the wheel slip is determined and the response delay of the engine is taken into consideration, the time constant is extended, so that the drive wheel speed is gradually converged to the target drive wheel speed. The torque value commanded to the driving motor is corrected using a parameter that takes into account the response delay of the engine.

Prior art documents

Patent document

Patent document 1: japanese patent laid-open publication No. 2013-151247

Problems to be solved by the invention

As described above, the device of patent document 1 is configured to correct the torque value commanded to the drive motor in consideration of the response delay of the engine when the wheel slips due to an increase in the braking force during the direct distribution control. However, since the control is performed when the wheels have slipped, for example, when the responsiveness of the control is reduced (reduced by a control delay or an interference element different from the control content), the generated power of the generator driven by the engine may not follow the rotation speed of the drive wheels regardless of whether the drive wheel speed is rapidly reduced from slipping to gripping of the wheels. That is, since the driving power of the driving motor is forcibly reduced by the grip of the wheels and the generated power of the generator is not reduced, the battery may be charged with electric power of an amount that the driving power cannot be consumed (that is, discharged), and the battery may be overcharged. In the configuration of patent document 1, the time constant of the control parameter is extended to ensure the response delay of the engine, so that there is a possibility that the responsiveness of the control of the entire vehicle is reduced by the amount of the extended time constant. Therefore, in such a situation, there is still room for improvement in terms of suppressing overcharge of the battery and controlling the power balance of the battery within a predetermined range.

Disclosure of Invention

The present invention has been made in view of the above-described problems, and an object thereof is to provide a control device for a hybrid vehicle that can suppress overcharge of a battery even when a driving wheel speed is rapidly reduced.

Means for solving the problems

In order to achieve the above object, the present invention provides a control device for a hybrid vehicle, including: an engine; a generator driven by the engine; a drive motor that is coupled to a drive wheel and supplied with electric power to output a drive torque for traveling; and a power storage device capable of charging electric power generated by the generator, wherein the control device of the hybrid vehicle is configured to charge the generated electric power to the power storage device or directly supply the generated electric power to the driving motor, and the control device is provided with a controller configured to control the generator, wherein the controller is configured to determine whether or not there is a possibility of locking of the driving wheels, and when it is determined that there is a possibility of locking of the driving wheels, control the electric power generated by the generator to be equal to or less than a predetermined electric power that can be input to the power storage device.

In the present invention, the vehicle may further include a control system that controls a posture and an operation of the vehicle, and the controller may be configured to determine whether or not the drive wheel is likely to be locked, when a control signal of a sensor related to the control system is abnormal, as the possibility of locking the drive wheel.

In the present invention, the controller may be configured to further determine whether or not the control system is turned off when it is determined that locking of the drive wheels is not possible, and to control the electric power generated by the generator to be equal to or less than an upper limit value obtained from the predetermined electric power that can be input to the power storage device and the electric power consumption based on the vehicle speed when the control system is turned off.

In the present invention, the controller may be configured to control the electric power generated by the generator to be equal to or less than an upper limit value obtained from the predetermined electric power that can be input to the power storage device and the electric power consumed based on the wheel speed of the drive wheel when the control system is turned on.

Further, in the present invention, the hybrid vehicle may be a series hybrid vehicle that drives the generator by power of the engine to generate electric power, and the drive motor transmits the drive torque for running to the drive wheels based on electric power generated by the electric power generation to run.

In the present invention, the hybrid vehicle may be a hybrid vehicle capable of selecting a series HV running mode in which the generator is driven by power of the engine to generate electric power and the driving motor transmits the driving torque for running to the drive wheels based on the electric power generated by the electric power generation to run, and a parallel HV running mode in which the driving motor transmits the torque of the engine and the driving torque of the driving motor to the drive wheels to run, and the controller may be configured to further determine whether or not warm-up of the engine is completed when determining that there is a possibility of locking of the drive wheels during running in the series HV running mode, and to determine that warm-up of the engine is completed when determining that warm-up of the engine is completed, switching a travel mode from the series HV travel mode to the parallel HV travel mode.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the control device for a hybrid vehicle of the present invention, when there is a possibility of locking of the drive wheels, the electric power generated by the generator (i.e., the generated electric power) is controlled to be equal to or less than a predetermined electric power value that can be input to the power storage device. Therefore, even when the electric power generated by locking of the drive wheels to which the drive motor is coupled is not consumed as the drive power and is charged into the power storage device, the electric power is limited to a predetermined value or less. Therefore, it is possible to prevent or suppress overcharge of the power storage device and degradation of the power storage device associated therewith.

Further, according to the present invention, when the drive wheels are not locked and a control system (e.g., ABS, TRC, etc.) for stabilizing the posture and the operation of the vehicle is turned off, the electric power generated by the generator is controlled to be equal to or less than the upper limit value obtained from the predetermined electric power that can be input to the power storage device and the consumed electric power based on the vehicle speed. Therefore, even when the control system is off and there is a possibility that the drive wheels may slip, for example, the electric power generated by the generator consumes the electric power as the drive power for traveling at the vehicle speed, and the predetermined electric power is charged into the power storage device. That is, the control is performed so that the consumed discharge and the charging of the power storage device are within a predetermined range (range in which the power balance is established) in which the deterioration of the performance of the power storage device is suppressed. Therefore, overcharge of the power storage device can be suppressed or prevented, and deterioration of the power storage device can be suppressed.

Further, according to the present invention, since the drive wheels are unlikely to slip when the control system for stabilizing the posture and the behavior of the vehicle is turned on, the electric power generated by the generator is controlled to be equal to or lower than the upper limit value obtained from the predetermined electric power that can be input to the power storage device and the consumed electric power based on the wheel speed of the drive wheels. That is, the generated electric power is consumed as driving power based on the wheel speed of the driving wheel, and a predetermined electric power is charged into the power storage device. That is, the control is performed so that the discharge and the charge fall within a predetermined range in which the deterioration of the performance of the power storage device is suppressed. Therefore, overcharge of the power storage device can be suppressed or prevented, and deterioration of the power storage device can be suppressed.

Further, according to the present invention, the parallel HV running mode in which the vehicle runs by transmitting the engine torque and the motor torque to the drive wheels and generating the drive force can be selected. In addition, when there is a possibility of locking of the drive wheels, it is determined whether or not the warm-up of the engine is completed. When warm-up of the engine is completed, the running mode is switched from the series HV running mode to the parallel HV running mode. That is, when the driving wheels are likely to be locked and the warm-up of the engine is completed, the vehicle is configured to run with the electric power generated by the generator set to "0". Therefore, the power storage device is not charged with electric power, and as a result, overcharging of the power storage device can be prevented.

Drawings

Fig. 1 is a diagram showing an example of a drive system (drive system and control system) of a hybrid vehicle to which the present invention is directed.

Fig. 2 is a flowchart for explaining an example of control in the vehicle embodiment.

Fig. 3 is a diagram illustrating changes in generated power when the wheels transition from the slipping state to the gripping state.

Fig. 4 is a diagram showing another example of a drive system (drive system and control system) of a hybrid vehicle to which the present invention is applied.

Fig. 5 is a flowchart for explaining another example of control in the embodiment of the present invention.

Fig. 6 is a reference example to which the present invention can be applied, and is a flowchart for explaining a control example thereof.

Description of reference numerals

The vehicle comprises an Engine (ENG)1 …, a first motor (MG1)2 …, a second motor (MG2)3 …, a Battery (BATT)4 …, driving wheels 5 …, a detection part 7 …, a controller (ECU)8 … and a vehicle Ve ….

Detailed Description

Embodiments of the present invention are explained with reference to the drawings. The embodiments described below are merely examples of embodying the present invention, and do not limit the present invention.

In the embodiment of the present invention, the vehicle to be controlled is a hybrid vehicle including a generator (or a motor having a power generation function) driven by an engine to generate electric power and a driving motor (or a motor having a power generation function) supplied with electric power from the generator to output a torque for traveling, and the hybrid vehicle is capable of traveling by transmitting the torque output by the driving motor to a driving wheel. Fig. 1 shows an example of a drive system (drive system and control system) of a hybrid vehicle as a control target in an embodiment of the present invention. A hybrid vehicle (hereinafter, referred to as a vehicle) Ve shown in fig. 1 is a so-called series hybrid vehicle, and includes, as power sources, an Engine (ENG)1, a first electric motor (MG1)2, and a second electric motor (MG2) 3. As other main components, the vehicle Ve includes a Battery (BATT)4, drive wheels 5, an accelerator pedal 6, a detection unit 7, and a controller (ECU) 8.

The engine 1 is a conventionally known internal combustion engine such as a gasoline engine or a diesel engine, and is an internal combustion engine that needs to be driven (started) by an electric motor for starting. The engine 1 is configured to electrically control an operation state such as adjustment of an output and start and stop of the engine. For example, in the case of a gasoline engine, the opening degree of a throttle valve, the amount of fuel supplied or injected, the execution and stop of ignition, the ignition timing, and the like are electrically controlled. In the case of a diesel engine, the amount of fuel injection, the timing of fuel injection, the opening degree of a throttle valve in an EGR (Exhaust Gas Recirculation) system, and the like are electrically controlled.

The first electric motor 2 is disposed on the output side of the engine 1. The first electric motor 2 has at least a function as a generator that generates electric power by being driven by receiving the engine torque output from the engine 1, and can also function as a motor for motoring the electric motor of the engine 1. That is, the first electric motor 2 is an electric motor (so-called motor generator) having a power generation function, and is configured by, for example, a permanent magnet type synchronous motor, an induction motor, or the like. The battery 4 is connected to the first motor 2 via a first inverter (INV1) 9. Therefore, the first electric motor 2 can be driven as a generator, and electricity generated at this time can be stored in the battery 4.

The second electric motor 3 has at least a function as a power source that is driven by being supplied with electric power to output a motor torque. In the vehicle Ve according to the embodiment of the present invention, the second electric motor 3 also has a function as a generator that is driven by receiving torque from the outside to generate electric power. That is, the second electric motor 3 is an electric motor (so-called motor generator) having a power generation function, and is configured by, for example, a permanent magnet type synchronous motor, an induction motor, or the like, as in the first electric motor 2. The battery 4 is connected to the second motor 3 via a second inverter (INV2) 10. Therefore, the electric power stored in the battery 4 can be supplied to the second electric motor 3, and the second electric motor 3 can be driven as a power source to output the motor torque. The first motor 2 and the second motor 3 are connected to each other via a first inverter 9 and a second inverter 10 so as to be able to receive and transmit electric power. For example, the electric power generated by the first electric motor 2 may be directly supplied to the second electric motor 3, and the second electric motor 3 may output the motor torque. The second electric motor 3 corresponds to a "driving motor" in the embodiment of the present invention.

The Battery (BATT)4 is a power storage device that stores electricity generated by the first electric motor 2 and the second electric motor 3, and is connected to the first electric motor 2 and the second electric motor 3 so as to be able to receive and transmit electric power to and from the first electric motor 2 and the second electric motor 3, respectively. Therefore, as described above, the electricity generated by the first electric motor 2 can be stored in the battery 4. Further, the first electric motor 2 can be driven by supplying the electric power stored in the battery 4 to the first electric motor 2. Similarly, as described above, electricity generated by the second electric motor 3 can be stored in the battery 4. Further, the second electric motor 3 can be driven by supplying the electric power stored in the battery 4 to the second electric motor 3. The power storage device is not limited to a secondary battery such as a nickel metal hydride battery or a lithium ion battery, and may be a capacitor (capacitance), for example.

The drive wheels (rear wheels in the example of fig. 1) 5 are wheels that generate drive force of the vehicle Ve by transmitting drive torque output by the drive force source. In the example shown in fig. 1, the drive wheels 5 are coupled to the second electric motor 3 via a propeller shaft 11, a differential gear 12, and a drive shaft 13. Therefore, in the example shown in fig. 1, the vehicle Ve is configured as a rear wheel drive vehicle that transmits the drive torque of the second electric motor 3 to the rear wheels to generate a drive force. The vehicle Ve according to the embodiment of the present invention may be a front wheel drive vehicle that generates driving force by transmitting driving torque to front wheels. Alternatively, the vehicle may be a four-wheel (all-wheel) drive vehicle in which drive torque is transmitted to both the front wheels and the rear wheels to generate drive force.

The second electric motor 3 may be coupled to the drive wheels 5 via a speed reduction mechanism (not shown). The speed reduction mechanism may be any of various speed change mechanisms that can change a speed ratio, such as a conventionally known stepped transmission or a continuously variable transmission, or may be a speed reduction mechanism having a fixed gear ratio.

The accelerator pedal 6 is an operation device that is operated by the driver to control the driving force of the vehicle Ve. The vehicle Ve is configured to adjust the power generated by the drive power source, that is, the engine torque and the motor torque, in accordance with the operation amount or the depression amount (accelerator opening degree) of the accelerator pedal 6. As will be described later, an accelerator position sensor 7c for detecting an accelerator operation amount and an accelerator operation speed is provided at the accelerator pedal 6. The accelerator position sensor 7c outputs an electric signal corresponding to the accelerator operation amount and the accelerator operation speed as detection data.

The controller (ECU)8 mainly controls the engine 1, the first electric motor 2, and the second electric motor 3, respectively. The controller 8 is an electronic control device mainly composed of a microcomputer, for example, and is inputted with various data detected or calculated by the detection unit 7. The input signal is, for example, a detection signal from: a vehicle speed sensor 7a that detects a vehicle speed, a wheel speed sensor 7b that detects a rotation speed of each wheel, an accelerator position sensor 7c that detects an accelerator operation amount (accelerator opening) and an accelerator operation speed of the accelerator pedal 6 by the driver, an engine rotation speed sensor 7d that detects a rotation speed of the engine 1, a first motor rotation speed sensor (or resolver) 7e that detects a rotation angle or a rotation speed of the first electric motor 2, a second motor rotation speed sensor (or resolver) 7f that detects a rotation angle or a rotation speed of the second electric motor 3, an SOC sensor 7g that detects a remaining battery power amount of the battery 4, a steering angle sensor 7h that detects a steering angle of a steering, and various sensors 7i related to a control system (ABS, TRC, etc.) that stabilizes a posture and an operation of the vehicle.

The data stored in advance includes a map for determining a running mode, a map for determining a required driving force, and a required generated power (required generated power). The control device is configured to perform an operation using the input data, the prestored data, and the like, and output a control command signal based on the operation result. Further, although an example in which one ECU is provided is shown in the example of fig. 1, a plurality of ECUs may be provided, for example, in accordance with the device to be controlled or in accordance with the content of control.

As described above, the vehicle Ve according to the embodiment of the present invention can travel in a plurality of travel modes, i.e., the EV travel mode (electric travel mode) and the HV travel mode (hybrid travel mode), by controlling the engine 1, the first electric motor 2, and the second electric motor 3 by the controller 8. Specifically, it is possible to set any one of an EV running mode in which the motor torque output by the second electric motor 3 is transmitted to the drive wheels 5 with the engine 1 stopped to generate the drive force and a series HV running mode in which the first electric motor 2 is driven by the engine torque to generate the electric power while the engine 1 is operated and the motor torque of the second electric motor 3 is transmitted to the drive wheels 5 to generate the drive force to run. These running modes can be set based on, for example, a switching map of the running mode in which the required driving force and the vehicle speed are used as parameters.

As described above, in the vehicle Ve shown in fig. 1, the first electric motor 2 is driven by the engine 1 to generate electric power, and the generated electric power is stored in the battery 4 or directly supplied to the second electric motor 3. The engine power (engine output) and the generated power of the first electric motor 2 are obtained from the rotation speed of the drive wheels 5 and the accelerator opening degree, and the engine power and the generated power are controlled based on the required generated power. The drive torque of the second electric motor 3 is obtained by obtaining a required drive power from the rotation speed of the drive wheels 5 and the accelerator opening degree, and controlling the motor torque so as to be the drive power. On the other hand, for example, when the rotation speed of the drive wheels 5 is abruptly reduced by an unexpected disturbance, although the consumption (discharge) of electric power in the second electric motor 3 is abruptly reduced, the generated power of the first electric motor 2 may not follow the rotation speed of the drive wheels 5. In such a case, for example, when the electric power (Win) that can be input to the battery 4 is limited, or when the battery level of the battery 4 reaches a predetermined value or more, such as when the battery level approaches a fully charged state, the electric power generated by the first electric motor 2 may be charged into the battery 4, which may result in overcharging of the battery 4. Therefore, in the embodiment of the present invention, the generated power of the first electric motor 2 is controlled in accordance with the state of the vehicle Ve. The generated power corresponds to "power generated by the generator" in the embodiment of the present invention. An example of control performed by the controller 8 will be described below.

Fig. 2 is a flowchart showing an example of this control, and first, it is determined whether or not the running state of the vehicle Ve is the series HV running mode (step S1). As described above, this control example is a control example of controlling the generated power of the first electric motor 2 driven and generated by the engine 1, and in the vehicle Ve in fig. 1, the EV running mode and the series HV running mode can be selected as the running mode. Therefore, for example, when the EV running mode is selected, a negative determination is made in step S1, and the process returns without executing the control thereafter.

On the other hand, when an affirmative determination is made in step S1, that is, when the series HV running mode is selected as the running mode, it is determined whether or not there is a possibility of an abnormality in the brake (step S2). This is a step of determining whether or not there is a possibility of locking of the drive wheels 5, and if there is an abnormality in each control signal of the vehicle speed sensor 7a, the wheel speed sensor 7b, the steering angle sensor 7h, the various sensors 7i relating to the control system for stabilizing the posture and the operation of the vehicle, for example, it is determined that there is a possibility of an abnormality in the brake. In addition, the abnormality of the various sensors may be determined to be present when, for example, a warning lamp displayed on an instrument panel is turned on.

Therefore, when an affirmative determination is made in step S2, that is, when it is determined that there is a possibility of brake abnormality such as the possibility of locking of the drive wheels 5, the generated power of the first electric motor 2 is set to be equal to or less than the electric power (also referred to as Win) that can be input to the battery 4 (step S3). The electric power that can be input to the battery 4 is acceptable electric power (in other words, allowable electric power) that is determined from the performance of the battery 4, and is a predetermined electric power value that suppresses overcharge of the battery 4. That is, even when the drive wheels 5 are locked and the electric power generated by the first electric motor 2 cannot be consumed and the generated electric power is charged in the battery 4, the generated electric power in step S3 is controlled to an electric power value that can suppress or prevent overcharging of the battery 4.

On the other hand, in the case where a negative determination is made in the above-described step S2, that is, in the case where it is determined that there is no possibility of an abnormality of the brake, it is subsequently determined whether or not the control system (e.g., ABS, TRC, etc.) having the function of stabilizing the posture and the behavior of the vehicle Ve, such as suppressing a slip of the drive wheels 5, is turned off (step S4). This is a step of determining whether or not there is a possibility of the drive wheels 5 slipping although the drive wheels 5 are not locked. Therefore, if an affirmative determination is made in step S4, that is, if various control systems for stabilizing the posture or the behavior of the Vehicle Ve, such as an ABS (antilock brake system), a TRC (traction control), a VSC (Vehicle sideslip prevention device), and a VDIM (Vehicle Dynamics integrated management), are turned off, the generated power in the first electric motor 2 is calculated at the Vehicle body speed (Vehicle speed) (step S5). The VDIM is a system that comprehensively controls various operations such as traveling, turning, and stopping of the vehicle in order to ensure driving stability.

That is, when such a control system is turned off, since there is a possibility that the drive wheels 5 slip, the generated power of the first electric motor 2 is controlled to be the generated power in consideration of the vehicle speed. Specifically, the control is performed so as to be equal to or lower than the upper limit value obtained from the predetermined electric power that can be input to the battery 4 and the electric power consumption based on the vehicle speed, which are described in step S3. That is, the upper limit value is the electric power obtained by adding the predetermined electric power obtained from the performance of the battery 4 to the electric power that can be consumed as the driving power of the second electric motor 3 based on the vehicle speed. In other words, the generated power of the first electric motor 2 is controlled so that the power balance between the discharge consumed during running and the charge to the battery 4 (the sum of the discharge and the charge) is within a predetermined range in which the overcharge of the battery 4 is suppressed.

Here, the generated power in the case where the drive wheels 5 transition from the slipping state to the gripping state is explained. Fig. 3 is a diagram for explaining this example, in which the accelerator opening degree is constant, and the generated power in the case where the drive wheels 5 slip and the generated power in the case where the grip is made from the slip state are indicated by reference numerals A, B (a > B), respectively. That is, in the example shown in fig. 3, the rotation speed of the second electric motor 3 is increased in the case of the slip state, and the generated power (a) obtained from the motor torque and the motor rotation speed is large, whereas the rotation speed of the drive wheels 5 is abruptly decreased and the generated power (B) is decreased in the case where the drive wheels 5 transition from the slip state to the grip state. That is, when the control system such as the ABS or the TRC is turned off, the generated power of the difference may be charged in the battery 4, and therefore, the generated power is controlled based on the actual vehicle speed. In other words, the electric power balance between the discharge and the charge is controlled to a predetermined range in which the overcharge of the battery 4 is suppressed or prevented.

On the contrary, when a negative determination is made in step S4, that is, when the control system for stabilizing the posture and the behavior of the vehicle Ve is turned on, the generated power of the first electric motor 2 is calculated at the wheel speed (step S6). That is, when the control system such as the ABS, the TRC, or the like is turned on, the posture and the motion of the vehicle Ve are stable, and therefore, the generated power is controlled at the wheel speed (that is, the rotation speed of the second electric motor 3). Specifically, the control is performed so as to be equal to or lower than the upper limit value obtained from the predetermined electric power that can be input to the battery 4 and the electric power consumption based on the wheel speed of the drive wheels 5, which are described in step S3. That is, the upper limit value is an electric power value obtained by adding the predetermined electric power obtained from the performance of the battery 4 to the electric power consumption of the driving power of the second electric motor 3 based on the wheel speed. In short, in step S6, similarly to step S5, the generated power of the first electric motor 2 is controlled so that the sum of the discharge and the charge falls within a predetermined range in which the overcharge of the battery 4 is prevented. That is, the difference between the upper limit values of step S5 and step S6 is the difference between the upper limit values of the generated power and the slip amount of the drive wheels 5, that is, the slip amount, which is the difference between the rotation speed of the second electric motor 3 and the vehicle speed.

As described above, in the embodiment of the present invention, the electric power (generated power) generated by the first electric motor 2 is controlled based on the state of the vehicle Ve. That is, when there is a possibility of brake abnormality, it is determined that there is a possibility of locking of the drive wheels 5, and the generated power is controlled to be equal to or less than the electric power that can be input to the battery 4. Thus, since the electric power stored in the battery 4 is controlled to the electric power for preventing overcharge of the battery 4, overcharge of the battery 4 and performance degradation of the battery 4 can be suppressed or prevented.

Even when there is no possibility of brake abnormality, the generated power is controlled based on the vehicle speed when it is determined that there is a possibility of a slip of the drive wheels 5 due to the control system for stabilizing the posture of the vehicle Ve being turned off. That is, the generated power is controlled so that the sum of the power consumed as the drive power and the power stored in the battery 4 falls within a predetermined range in which the performance of the battery 4 is prevented from deteriorating. In other words, the control is performed such that the power balance between the discharge and the charge is within a predetermined range that can be tolerated by the battery 4. Therefore, it is possible to suppress or prevent overcharge of the battery 4 and deterioration of the performance of the battery 4. When the control system for stabilizing the posture of the vehicle Ve is turned on, the generated power is controlled based on the wheel speed. Even in this case, since the power balance control is performed such that the sum of the discharge and the charge falls within the above-described predetermined range, it is possible to suppress or prevent the overcharge of the battery 4 and the deterioration of the performance of the battery 4.

Next, another embodiment of the present invention will be described. In the control example described above, the series hybrid vehicle is used as the target vehicle Ve, but the target vehicle Ve may be a vehicle capable of so-called parallel running in which the vehicle runs with the output of the engine 1 and the second electric motor 3. Fig. 4 is a diagram showing an example of the vehicle Ve, and is configured to transmit the engine torque to the front wheels 14 and transmit the motor torque of the second electric motor to the rear wheels 5. Further, a clutch 15 that selectively transmits and disconnects power is provided between the engine 1 and the first electric motor 2, and the front wheels 14. The clutch 15 may be disposed on the output side of the first electric motor 2, for example, or may be incorporated in a transmission (not shown) that transmits torque between the engine 1 and the first electric motor 2 and the front wheels 14. In any case, the engine 1 and the first electric motor 2 are configured to be disconnected from the drive system of the vehicle Ve by releasing the clutch 15, whereas the engine 1 and the first electric motor 2 are configured to be connected to the drive system of the vehicle Ve by engaging the clutch 15.

Then, the engine torque is transmitted to the front wheels 14 via the clutch 15, the front propeller shaft 16, the front differential gear 17, and the front drive shaft 18. Since the other configurations are the same as those of fig. 1, the description thereof will be omitted.

The vehicle Ve in fig. 4 can travel in a plurality of the EV travel mode, the series HV travel mode, and the parallel HV travel mode described above by controlling the engine 1, the first electric motor 2, the second electric motor 3, and the clutch 15 by the controller 8. Specifically, it is possible to set any one of an EV running mode in which the motor torque output by the second electric motor 3 is transmitted to the rear wheels 5 with the engine 1 stopped to generate the driving force, a series HV running mode in which the engine 1 is operated with the clutch 15 released, the first electric motor 2 is driven by the engine torque to generate electric power, and the motor torque of the second electric motor 3 is transmitted to the rear wheels 5 to generate the driving force, and a parallel HV running mode in which the engine 1 is operated with the clutch 15 engaged to generate the driving force, the engine torque is transmitted to the front wheels 14, and the motor torque of the second electric motor 3 is transmitted to the rear wheels 5 to generate the driving force, to run. These running modes can be set to any of the above-described running modes based on, for example, a running mode switching map having the required driving force and the vehicle speed as parameters.

Fig. 5 is a control example for the vehicle Ve in fig. 4, and is configured to switch to the parallel HV running mode when a predetermined condition is satisfied, except that overcharge of the battery 4 and performance degradation of the battery 4 are suppressed, as in the control example in fig. 2. The following describes a flowchart in this control example. Note that steps similar to those in the control example of fig. 2 are denoted by the same reference numerals, and the description thereof is simplified or omitted.

First, it is determined whether or not the traveling state of the vehicle Ve is in the series HV traveling mode (step S1), and if the series HV traveling mode is selected, it is determined whether or not there is a possibility of an abnormality in the brake (step S2). If an affirmative determination is made in step S2, that is, if it is determined that there is a possibility of locking of the drive wheels (rear wheels coupled to the second electric motor) 5, it is subsequently determined whether or not warm-up of the engine 1 and the transmission is completed (step S100).

This is a step of determining whether or not the parallel HV running is possible, and whether or not the parallel HV running is possible. Further, the engine output during this warm-up period is relatively large as compared with the engine output for driving and generating the first electric motor 2 during series HV running. Therefore, if an affirmative determination is made in step S100, that is, if it is determined that warm-up of the engine 1 and the transmission is completed, the operation mode is switched from the series HV travel mode to the parallel HV travel mode (step S200). That is, the engine torque and the motor torque of the second electric motor 3 are transmitted to the wheels 5 and 14 to generate the driving force. In other words, the vehicle travels by the driving forces of the engine 1 and the second electric motor 3 without generating electric power in the first electric motor 2.

On the other hand, when a negative determination is made in step S100, that is, when it is determined that the warm-up of the engine 1 and the transmission has not been completed, the generated power of the first electric motor 2 is controlled to be equal to or less than the electric power (Win) that can be input to the battery 4 (step S3).

Further, when it is determined that there is no possibility of brake abnormality such as the possibility of locking of the drive wheels 5 in step S2, it is determined whether or not the control system (ABS, TRC, etc.) that stabilizes the posture and behavior of the vehicle Ve is turned off (step S4). When the control system is off, the generated power of the first electric motor 2 is calculated at the vehicle body speed (vehicle speed) (step S5). On the other hand, when the control system is on, the generated power of the first electric motor 2 is calculated at the wheel speed (step S6).

As described above, in the control example shown in fig. 5, when it is determined that there is a possibility of an abnormality in the brake, the generated power is controlled according to whether or not the warm-up of the engine 1 and the transmission is completed. That is, when warm-up of the engine 1 and the transmission is completed, the running mode is switched from the series HV running mode to the parallel HV running mode, and the driving torque of the engine 1 and the second electric motor 3 is transmitted to the wheels 5 and 14 to run. On the other hand, when it is determined that the warm-up of the engine 1 and the transmission has not been completed, the generated power is controlled to be equal to or less than the electric power (Win) that can be input to the battery 4, as in the control example of fig. 2. In either case, it is thereby possible to prevent overcharging of the battery 4 and to suppress or prevent deterioration of the performance of the battery 4.

Next, a reference example to which the present invention can be applied will be described. As described above, the control examples shown in fig. 2 and 5 include control for limiting the generated power to the electric power that can be input or less when there is a possibility of an abnormality in the brake. On the other hand, the present invention may be configured to suppress overcharge of the battery 4 when the rotation speed of the driving motor is rapidly reduced. Therefore, for example, the control example of fig. 5 may be modified so that the parallel HV running mode is uniformly switched to when there is a possibility of an abnormality in the brake. Fig. 6 is a flowchart illustrating this control example. Note that steps similar to those in the control example of fig. 5 are denoted by the same reference numerals, and the description thereof is simplified or omitted.

First, it is determined whether or not the series HV running mode is selected (step S1), and if the series HV running mode is selected, it is determined whether or not there is a possibility of an abnormality in the brake (step S2). If an affirmative determination is made in step S2, that is, if it is determined that there is a possibility of an abnormality in the brake, the operation mode is switched from the series HV travel mode to the parallel HV travel mode (step S200). Note that, when it is determined in step S2 that there is no possibility of an abnormality of the brake, such as the possibility of locking the drive wheels 5, the same applies to the example of fig. 5 described above. That is, it is determined whether or not the control system for stabilizing the posture and the behavior of the vehicle Ve is turned off (step S4), and when the control system is turned off, the generated power in the first electric motor 2 is calculated at the vehicle body speed (step S5). In contrast, when the control system is on, the generated power of the first electric motor 2 is calculated at the wheel speed (step S6). In this reference example, too, the generated power can be controlled within a predetermined range in accordance with the state of the vehicle Ve, and as a result, overcharging of the battery 4 and deterioration in the performance of the battery 4 can be suppressed or prevented.

While the embodiments of the present invention have been described above, the present invention is not limited to the above examples, and may be modified as appropriate within the scope of achieving the object of the present invention. In the above-described embodiment and the reference example, the example of controlling the generated power of the first electric motor when there is a possibility of locking the drive wheels 5 or when there is a possibility of slipping the drive wheels 5 has been described, but in any case, the present invention may be configured so that the overcharge of the battery 4 can be suppressed when the rotation speed of the drive wheels 5 coupled to the second electric motor 3 is rapidly reduced. Therefore, an example of the case where the rotation speed of the drive motor sharply decreases may not be limited to locking or slipping of the drive wheels 5.