JP2021024511A - Control device of hybrid vehicle - Google Patents

Abstract

To properly reduce discomfort given to a driver due to generation of deceleration when switching a travel mode.SOLUTION: A controller 20 as a control device of a hybrid vehicle determines whether a travel mode is switched from a first travel mode for traveling the hybrid vehicle 1 using torque of a motor 4 without using torque of an engine 2 to a second travel mode for traveling the hybrid vehicle 1 using torque of at least the engine 2. When determining that the travel mode is switched from the first travel mode to the second travel mode, a control to regenerate the motor 4 is performed so that the number of rotation of the motor 4 is decreased. After the control, a first clutch CL1 is shifted from a release state to a fastening state so that the torque of the motor 4 is transmitted to the engine 2 through the first clutch CL1 and the engine is cranked by the motor 4 so as to start the engine 2.SELECTED DRAWING: Figure 10

Description

The present invention relates to a hybrid vehicle control device comprising an engine, a motor, and a clutch that switches between transmission and interruption of torque between the engine and the motor.

Conventionally, in a hybrid vehicle equipped with an engine and a motor as power sources and driven by at least one of the driving force of the engine and the driving force of the motor, a technique of cranking the engine by the motor and starting the engine has been proposed. .. For example, Patent Document 1 describes that when the mode shifts from the mode of traveling by the torque of the motor to the mode of traveling by the torque of the engine and the motor, the torque of the motor is calculated based on the transmission torque of the clutch provided between the engine and the motor. A technique for suppressing a torque shock from being generated in a vehicle due to the connection of a clutch by changing the clutch is disclosed.

JP-A-2018-30507

By the way, conventionally, a motor (typically a permanent magnet motor) having a characteristic that the generated torque gradually decreases as the rotation speed increases has been widely used. When a motor having such characteristics is applied to a hybrid vehicle, the traveling mode in which the hybrid vehicle is driven by using the torque of the motor without using the torque of the engine (hereinafter, appropriately referred to as "first traveling mode") When switching to a driving mode in which the hybrid vehicle is driven by using at least the torque of the engine (hereinafter, appropriately referred to as a "second driving mode"), a relatively large deceleration occurs in the hybrid vehicle when the engine is started. I have something to do. The reason is as follows.

When a motor having the above-mentioned characteristics is used, the torque that can be generated by the motor becomes relatively small when the rotation speed of the motor is relatively high in the first traveling mode. When the torque that can be generated by the motor in the first running mode is relatively small in this way, when the engine is started by using the torque of the motor when switching from the first running mode to the second running mode ( That is, when the motor cranks and starts the engine), the motor may not be able to generate sufficient torque to start the engine. In this case, the torque used for traveling the hybrid vehicle is used to start the engine, that is, the torque is drawn from the vehicle side to the engine. As a result, when switching from the first traveling mode to the second traveling mode, a relatively large deceleration may occur in the hybrid vehicle, which may give the driver a sense of discomfort.

The present invention has been made to solve the above-mentioned problems of the prior art, and the engine is used from a traveling mode using a motor for a hybrid vehicle having an engine, a motor, and a clutch provided between them. It is an object of the present invention to provide a control device for a hybrid vehicle capable of appropriately suppressing the discomfort given to the driver due to the occurrence of deceleration when switching to the traveling mode.

In order to achieve the above object, the present invention is a control device for a hybrid vehicle having an engine, a motor, and a clutch for switching between transmission and interruption of torque between the engine and the motor. From the first driving mode in which the hybrid vehicle is driven by using the torque of the motor without using the torque of the engine by setting the released state, the clutch is set to the engaged state and at least the torque of the engine is used to drive the hybrid vehicle. The running mode of the hybrid vehicle is changed from the first running mode to the second running mode by the running mode determining means for determining whether or not to switch the running mode of the hybrid vehicle to the second running mode for running, and the running mode judging means. When it is determined to switch, the motor control means that controls to regenerate the motor so as to reduce the rotation speed of the motor, and after the control by the motor control means, the torque of the motor is transmitted to the engine via the clutch. In addition, a clutch control means for shifting the clutch from the released state to the engaged state, and a cranking control means for cranking the engine by a motor to start the engine during and / or after control by the clutch control means. It is characterized by having.

In the present invention configured as described above, the control device for the hybrid vehicle controls to regenerate the motor so as to reduce the rotation speed of the motor when switching from the first traveling mode to the second traveling mode. , The clutch is changed from the released state to the engaged state, and the engine is cranked by the motor to start the engine. That is, when switching from the first traveling mode to the second traveling mode, the control device of the hybrid vehicle controls to regenerate the motor before starting the engine to temporarily reduce the rotation speed of the motor.

According to the present invention as described above, when the engine is started for switching the traveling mode, a relatively large torque can be generated from the motor. Therefore, the torque required to start the engine is calculated by the motor. It will be possible to realize it effectively by the torque of. For example, the torque of the motor allows most of the torque required to start the engine to be achieved. As a result, the torque on the hybrid vehicle side can be suppressed as much as possible from being used to start the engine, and the deceleration that occurs in the hybrid vehicle can be appropriately reduced. Therefore, it is possible to appropriately suppress the discomfort given to the driver when switching from the first traveling mode to the second traveling mode.

In the present invention, preferably, the motor control means requires the driver to accelerate the hybrid vehicle when it is determined by the traveling mode determining means that the traveling mode of the hybrid vehicle is switched from the first traveling mode to the second traveling mode. If there is, the control to regenerate the motor is not performed, and if there is no request from the driver to accelerate the hybrid vehicle, the control to regenerate the motor is performed.
According to the present invention configured in this way, when there is an acceleration request from the driver, the engine can be started quickly by preventing the motor from being regenerated when switching the traveling mode as described above. , The acceleration request from the driver can be appropriately realized.

In the present invention, preferably, when the motor control means determines that the travel mode of the hybrid vehicle is switched from the first travel mode to the second travel mode by the travel mode determining means, the rotation speed of the motor is determined by the motor. If the torque is within the range of the number of revolutions that can generate torque above a predetermined value, the control to regenerate the motor is not performed, and if the number of revolutions of the motor is not within the range, the control to regenerate the motor is performed. Do.
If the rotation speed of the motor is within the range of the rotation speed that can generate torque above a predetermined value, the motor is already in a state where it can generate sufficient torque, so it is necessary to intentionally reduce the rotation speed of the motor. Absent. Therefore, in this case, the prompt start of the engine can be appropriately prioritized by not regenerating the motor when switching the traveling mode as described above.

In the present invention, preferably, the hybrid vehicle further includes a transmission provided on the power transmission path between the engine and the motor and the drive wheels, and the motor control means travels the hybrid vehicle by the travel mode determining means. When it is determined that the mode is switched from the first driving mode to the second driving mode, the motor rotation speed should be reduced by regeneration based on the current gear stage of the transmission and the current rotation speed of the motor. A target rotation speed is set, and control is performed to regenerate the motor so as to reduce the rotation speed of the motor to the target rotation speed.
According to the present invention configured as described above, the target rotation speed at which the rotation speed of the motor should be reduced by regeneration is set based on the current gear stage of the transmission and the current rotation speed of the motor. It means that the torque on the vehicle side that is generated when switching from the traveling mode to the second traveling mode is drawn (the torque for traveling is drawn into the engine, the motor, etc., so that the deceleration of the hybrid vehicle occurs. The same shall apply hereinafter.) Can be appropriately suppressed.

In the present invention, preferably, the motor control means is reduced due to the torque of the hybrid vehicle and the reduction of the motor rotation speed, which are reduced due to the start of the engine, according to the current gear stage and the current rotation speed. The target rotation speed is set based on the torque of the hybrid vehicle.
According to the present invention configured in this way, both the deceleration caused by the decrease in the rotation speed of the motor and the deceleration caused by the start of the engine can be reduced in a well-balanced manner, and the discomfort given to the driver can be appropriately suppressed. It becomes possible to do.

In the present invention, preferably, the motor control means controls to regenerate the motor so that the decrease in the rotation speed of the motor ends within an acceptable predetermined time in the switching of the traveling mode.
According to the present invention configured as described above, it is possible to appropriately suppress that the switching from the first traveling mode to the second traveling mode is prolonged, that is, the engine start is delayed.

In the present invention, preferably, when the clutch for switching between the transmission and the disconnection of torque between the engine and the motor is the first clutch, the hybrid vehicle has the first clutch as well as the engine and the motor and the drive wheels. Further, when it is determined by the traveling mode determining means that the traveling mode of the hybrid vehicle is switched from the first traveling mode to the second traveling mode. In addition, before the control by the motor control means, the control for shifting the second clutch from the engaged state to the slip state is performed.
According to the present invention configured as described above, by setting the second clutch in the slip state during the switching of the traveling mode, the pulling of the traveling torque generated at the time of the switching is suppressed as much as possible. At the same time, the second clutch can be completely engaged after the engine is started.

In the present invention, preferably, the hybrid vehicle further comprises an automatic transmission provided on a power transmission path between the engine and motor and the drive wheels and equipped with planetary gears.
Since an automatic transmission equipped with planetary gears has a large inertia, it is easy for torque for traveling to be drawn when switching the traveling mode. However, as described above for a hybrid vehicle equipped with such an automatic transmission. By applying the control according to the present invention, it is possible to appropriately suppress the occurrence of deceleration due to the pulling of torque for traveling.

In a preferred example of the present invention, the motor has a characteristic that the torque generated decreases as the number of rotations increases.

According to the control device for the hybrid vehicle of the present invention, it is possible to appropriately suppress the discomfort given to the driver due to the occurrence of deceleration when switching from the traveling mode using the motor to the traveling mode using the engine.

It is a schematic block diagram of the hybrid vehicle to which the control device of the hybrid vehicle according to the embodiment of this invention is applied. It is explanatory drawing about the characteristic of the motor applied to the hybrid vehicle by embodiment of this invention. It is a block diagram which shows the electric structure of the control device of the hybrid vehicle by embodiment of this invention. It is a flowchart which shows the whole process of the engine start control by embodiment of this invention. It is a flowchart which shows the 1st engine start control by embodiment of this invention. It is a flowchart which shows the 2nd engine start control by embodiment of this invention. It is explanatory drawing of the method of making the map of the target motor rotation speed by embodiment of this invention. It is explanatory drawing of the relationship between the pull-in torque by starting an engine and the pull-in torque by a decrease in the rotation speed according to the embodiment of the present invention. It is explanatory drawing of the setting method of the target motor regenerative torque according to the target motor rotation speed by embodiment of this invention. An example of a time chart when the engine start control according to the embodiment of the present invention is executed is shown.

Hereinafter, a hybrid vehicle control device according to an embodiment of the present invention will be described with reference to the accompanying drawings.

<Device configuration>
FIG. 1 is a schematic configuration diagram of a hybrid vehicle to which a hybrid vehicle control device according to an embodiment of the present invention is applied.

As shown in FIG. 1, the hybrid vehicle 1 mainly includes an engine 2 (for example, a gasoline engine) that generates torque for driving the hybrid vehicle 1 and a downstream side of the engine 2 on the power transmission path of the hybrid vehicle 1. A motor 4 provided on the side that generates torque for driving the hybrid vehicle 1, a battery 5 that transfers power between the motor 4 via an inverter (not shown) or the like, and a power transmission path of the hybrid vehicle 1. A transmission 6 provided above and downstream of the motor 4 for shifting the rotational speed of the engine 2 and / or the motor 4, a power transmission system 8 for transmitting torque from the transmission 6 to the downstream side, and power transmission. It has a drive shaft 10 that drives the drive wheels 12 by torque from the system 8, and the drive wheels 12.

The output shaft of the engine 2 and the rotating shaft of the motor 4 are coaxially connected by a shaft AX1 via an intermittent first clutch CL1. The first clutch CL1 can switch between transmission and interruption of torque between the engine 2 and the motor 4. For example, the first clutch CL1 is composed of a dry multi-plate clutch capable of changing the transmission torque capacity by continuously or stepwise controlling the clutch hydraulic oil flow rate and the clutch hydraulic pressure by a motor (not shown).

The rotating shaft of the motor 4 and the rotating shaft of the transmission 6 are coaxially connected by the shaft AX2. The transmission 6 typically has one or more planetary gears (planetary gears) inside, and has a function to automatically switch gears (gear ratios) according to the vehicle speed, engine speed, and the like. It is an automatic transmission. Further, the transmission 6 includes an intermittent second clutch CL2 inside, and the second clutch CL2 allows the transmission 6 to be upstream (engine 2 and motor 4) and downstream of the transmission 6 (drive wheels 12). It is possible to switch between transmission and interruption of torque with (etc.). For example, the second clutch CL2 is also composed of a dry multi-plate clutch that can change the transmission torque capacity by continuously or stepwise controlling the clutch hydraulic oil flow rate and the clutch hydraulic pressure by a motor (not shown). The second clutch CL2 is actually composed of a large number of clutches used for switching various gears in the transmission 6.

Torque is input to the power transmission system 8 via the output shaft AX3 of the transmission 6. The power transmission system 8 includes a differential gear that distributes driving force to a pair of left and right drive wheels 12, a final gear, and the like.

The hybrid vehicle 1 can switch the traveling mode by switching between engaging and releasing the first clutch CL1. That is, the hybrid vehicle 1 has a first traveling mode in which the first clutch CL1 is set to the released state and the hybrid vehicle 1 is driven by using the torque of the motor 4 without using the torque of the engine 2, and the first clutch CL1. Has a second traveling mode in which the hybrid vehicle 1 is driven by using at least the torque of the engine 2 by setting the clutched state. The first driving mode is a so-called EV driving mode, and the second driving mode is an engine driving mode in which the hybrid vehicle 1 is driven by using only the torque of the engine 2, and the torques of both the engine 2 and the motor 4 are used. Includes a hybrid driving mode in which the hybrid vehicle 1 is driven.

Here, with reference to FIG. 2, the characteristics of the motor 4 applied to the hybrid vehicle 1 according to the embodiment of the present invention will be described. In FIG. 2, the horizontal axis represents the motor rotation speed, and the vertical axis represents the motor torque. As shown in FIG. 2, the motor 4 applied in the present embodiment has a characteristic that the torque generated decreases as the rotation speed increases. In other words, the motor 4 has a characteristic that the torque generated increases as the rotation speed decreases. In particular, the torque of the motor 4 is generally maximum when the rotation speed is less than the predetermined value N1, and when the rotation speed is equal to or more than the predetermined value N1, the torque decreases as the rotation speed increases. For example, a permanent magnet motor is applied to such a motor 4.

Next, FIG. 3 is a block diagram showing an electrical configuration of a control device for a hybrid vehicle according to an embodiment of the present invention.

As shown in FIG. 3, the controller 20 includes a signal from the engine rotation speed sensor SN1 that detects the rotation speed of the engine 2, a signal from the motor rotation speed sensor SN2 that detects the rotation speed of the motor 4, and a driver. A signal from the accelerator opening sensor SN3 that detects the accelerator opening corresponding to the amount of depression of the accelerator pedal, a signal from the vehicle speed sensor SN4 that detects the vehicle speed of the hybrid vehicle 1, and a gear stage set in the transmission 6. A signal from the gear stage sensor SN5 for detecting the above and a signal from the SOC sensor SN6 for detecting the SOC (State of Charge) indicating the charging state of the battery 5 are input.

The controller 20 includes one or more processors (typically a CPU) and various programs (basic control programs such as an OS) that are interpreted and executed on the processors, and application programs that are started on the OS and realize specific functions. ), And an internal memory such as a ROM or RAM for storing programs and various data, and a computer. The controller 20 corresponds to an example of the "hybrid vehicle control device" in the present invention.

Specifically, the controller 20 mainly outputs control signals to the engine 2, the motor 4, the first clutch CL1 and the second clutch CL2 based on the detection signals from the sensors SN1 to SN6 described above, and these To control. For example, the controller 20 controls to adjust the ignition timing, fuel injection timing, and fuel injection amount of the engine 2, controls to adjust the rotation speed and torque of the motor 4, and controls the first and second clutches CL1 and CL2, respectively. Controls switching between fastening and releasing. In reality, the controller 20 controls the spark plug, fuel injection valve, throttle valve, etc. of the engine 2, controls the motor 4 via an inverter, and controls the first and second clutches CL1 via a hydraulic control circuit. , CL2 is controlled.

Further, in the present embodiment, the controller 20 has a traveling mode determination unit 20a, a motor control unit 20b, a clutch control unit 20c, and a cranking control unit 20d as functional components. The travel mode determination unit 20a determines whether or not to switch the travel mode of the hybrid vehicle 1 from the first travel mode to the second travel mode based on the detection signals from the sensors SN1 to SN6 described above. The motor control unit 20b controls to regenerate the motor 4 so as to reduce the rotation speed of the motor 4 when the travel mode determination unit 20a determines that the first travel mode is switched to the second travel mode. The clutch control unit 20c controls to shift the second clutch CL2 from the engaged state to the slip state before the control by the motor control unit 20b, and releases the first clutch CL1 after the control by the motor control unit 20b. Controls the transition from the state to the fastened state. The cranking control unit 20d is in the process of shifting the first clutch CL1 from the released state to the engaged state by the clutch control section 20c and / or after the transition is completed (in a state where the first clutch CL1 can transmit torque). If there is, it may be during the transition or after the transition is completed), the engine 2 is cranked by the motor 4 in order to start the engine 2.

In the present embodiment, even when the motor control unit 20b is determined by the travel mode determination unit 20a to switch from the first travel mode to the second travel mode, when a predetermined condition is satisfied. , The control for regenerating the motor 4 described above is not performed. In realizing this, the controller 20 (for example, providing a prohibition unit in the controller 20) may issue a command to prohibit the execution of control by the motor control unit 20b when a predetermined condition is satisfied.

<Engine start control>
Next, the control content performed by the controller 20 in the embodiment of the present invention will be described. In the present embodiment, the controller 20 travels from the first travel mode (EV travel mode) in which the hybrid vehicle 1 travels using the torque of the motor 4 to the second travel mode in which the hybrid vehicle 1 travels using at least the torque of the engine 2. When switching to the mode (engine running mode or hybrid running mode), control for starting the engine 2 (engine starting control) is performed. In this case, the controller 20 controls the engine start by controlling the engine 2, the motor 4, the first clutch CL1 and the second clutch CL2.

First, an outline of engine start control according to the present embodiment will be described. As described above, when the motor 4 (see FIG. 2) having the characteristic that the generated torque decreases as the rotation speed increases, the hybrid vehicle 1 is used when switching from the first traveling mode to the second traveling mode. In some cases, a relatively large deceleration may occur. This is because when switching from the first running mode to the second running mode, the torque of the motor 4 is used to start the engine 2 (that is, the motor 4 cranks and starts the engine 2). When the motor rotation speed is relatively high in the traveling mode, the torque of the motor 4 is relatively small, so that the torque required to start the engine 2 (the resistance of the engine 2, the variation of the first clutch CL1 and the transmission 6 This is because the motor 4 cannot sufficiently generate the torque including the loss (the same shall apply hereinafter). In other words, the motor 4 cannot supply sufficient torque to the engine 2 to start the engine 2. In this case, the torque used for traveling the hybrid vehicle 1 is used to start the engine 2, that is, the traveling torque is drawn to the engine 2 side. As a result, a relatively large deceleration occurs in the hybrid vehicle 1, which may give the driver a sense of discomfort.

In order to deal with the above problems, in the present embodiment, the controller 20 controls to regenerate the motor 4 so as to reduce the motor rotation speed when switching from the first traveling mode to the second traveling mode. After that, the first clutch CL1 is shifted from the released state to the engaged state, and the engine 2 is cranked by the motor 4 to start the engine 2. That is, in the present embodiment, when switching from the first traveling mode to the second traveling mode, the controller 20 controls to regenerate the motor 4 before starting the engine 2 to temporarily reduce the motor rotation speed. Keep it.

As a result, when the engine 2 is started to switch the traveling mode, a relatively large torque can be generated from the motor 4, so that the torque required to start the engine 2 is the torque of the motor 4. Will be able to be realized effectively. Specifically, the torque of the motor 4 makes it possible to realize most of the torque required to start the engine 2. As a result, the traveling torque of the hybrid vehicle 1 can be suppressed as much as possible from being used for starting the engine 2, and the deceleration generated in the hybrid vehicle 1 can be appropriately reduced. Therefore, it is possible to appropriately suppress the discomfort given to the driver when switching from the first traveling mode to the second traveling mode.

On the other hand, in the present embodiment, when the controller 20 is requested by the driver to accelerate the hybrid vehicle 1 even when switching from the first traveling mode to the second traveling mode (typically, the accelerator by the driver). When the amount of change in the accelerator opening corresponding to the operation of the pedal is equal to or greater than a predetermined amount), the control for regenerating the motor 4 for lowering the motor rotation speed as described above is not performed. In this case, the controller 20 shifts the first clutch CL1 from the released state to the engaged state without lowering the motor rotation speed, and cranks the engine 2 by the motor 4 to start the engine 2. This is to promptly start the engine 2 in order to prioritize the acceleration request from the driver rather than suppressing the occurrence of deceleration as described above.

Hereinafter, the control according to the present embodiment in which the motor 4 is regenerated so as to reduce the motor rotation speed and then the engine 2 is started is appropriately referred to as "second engine start control". On the other hand, the control for starting the engine 2 which is executed when the control for regenerating the motor 4 is not performed as described above, that is, the start control of the engine 2 which is normally executed is appropriately "started from the first engine". Called "control".

Further, in the present embodiment, the controller 20 has a motor rotation speed of a torque equal to or higher than a predetermined value of the motor 4 even when switching from the first traveling mode to the second traveling mode (preferably, the traveling mode). When the motor torque (motor torque that can start the engine 2 while appropriately suppressing the occurrence of deceleration at the time of switching) is within the range of the possible rotation speed, the motor 4 for reducing the motor rotation speed Do not control to regenerate. That is, also in this case, the controller 20 executes the first engine start control instead of the second engine start control. In a typical example, the controller 20 performs the first engine start control when the motor rotation speed is less than a predetermined value N1 (see FIG. 2), that is, when the motor 4 is in a state where a substantially maximum torque can be generated. Execute. In this case, even if the motor 4 is lowered by the second engine start control, the torque of the motor 4 does not increase. In other words, since the motor 4 is already in a state where it can generate a sufficient torque, it is not necessary to dare to execute the second engine start control. Therefore, the controller 20 executes the normal first engine start control in order to start the engine 2 promptly.

Here, in the present embodiment, when both the first and second engine start control are requested to switch from the first traveling mode to the second traveling mode, the controller 20 first first clutches the second clutch. Control is performed to shift CL2 from the fastened state to the slip state. The reason why the second clutch CL2 is slipped in this way is to suppress the torque used for traveling of the hybrid vehicle 1 from being transmitted to the engine 2 side as much as possible when starting the engine 2. That is, this is to suppress the occurrence of a relatively large deceleration when the running torque is used to start the engine 2. On the other hand, if the second clutch CL2 is completely released, it is possible to reliably suppress the transmission of the traveling torque to the engine 2 side. However, once the second clutch CL2 is set to the completely released state in this way, it takes time to switch the second clutch CL2 to the engaged state after that, so that the traveling mode cannot be switched quickly. Therefore, in the present embodiment, the second clutch CL2 is set to the slip state in both the first and second engine start control. The second clutch CL2 is completely engaged after the engine 2 is ignited.

However, even if the second clutch CL2 is set to the slip state, additional torque is drawn by the inertia of the second clutch CL2. Specifically, even if the capacity of the second clutch CL2 is reduced, the reaction force of the inertia in the second clutch CL2, that is, the reaction force when the planetary gear in the transmission 6 corresponding to the second clutch CL2 idles. , Extra torque transmission will occur. That is, in the second clutch CL2, which is not in the completely released state but in the slip state, torque is transmitted to some extent, so that torque is pulled in accordingly. In addition to this torque pulling, the planet in the transmission 6 Additional torque is drawn as the gear rotation fluctuates.

The torque pull-in due to the inertia of the second clutch CL2 affects the torque pull-in at the time of starting the engine 2, but also affects the regeneration of the motor 4 in the second engine start control. .. That is, when the motor 4 is regenerated so as to reduce the motor rotation speed in the second engine start control, in addition to the torque drawn due to the torque transmission via the second clutch CL2 in the slipped state (second clutch). The torque transmitted from the drive wheel 12 side to the motor 4 side via the CL2 is used for the regeneration of the motor 4), and the torque is drawn in due to the inertia of the second clutch CL2 described above, so that the torque is reduced in the hybrid vehicle 1. Speed will be generated.

For this reason, when the second engine start control is performed when switching from the first traveling mode to the second traveling mode, the torque of the hybrid vehicle 1 first decreases due to the decrease in the rotation speed of the motor 4, and the speed is reduced. After that, when the engine 2 is started, the torque of the hybrid vehicle 1 is reduced and the speed is reduced. Basically, the deceleration that occurs twice is much smaller than the deceleration that occurs when the first engine start control is performed. However, in the present embodiment, in order to more appropriately reduce both of these two decelerations, the target motor rotation speed at which the rotation speed of the motor 4 should be reduced is set in the second engine start control.

Specifically, in the present embodiment, the controller 20 has a torque of the hybrid vehicle 1 (hereinafter, referred to as “pull-in torque due to a decrease in rotation speed”) and an engine 2 which are reduced due to a decrease in the rotation speed of the motor 4. The target motor rotation speed at which the rotation speed of the motor 4 should be reduced in the second engine start control based on the torque of the hybrid vehicle 1 (hereinafter referred to as "pull-in torque due to engine start") which is reduced due to the start of the second engine. Set the number. These pull-in torques have a trade-off relationship in which one becomes smaller and the other becomes larger according to the motor rotation speed. Therefore, typically, the controller 20 sets the rotation speed of the motor 4 that minimizes the sum of the pull-in torque due to the engine start and the pull-in torque due to the decrease in the rotation speed as the target motor rotation speed. As a result, both the deceleration caused by the decrease in the rotation speed of the motor 4 and the deceleration caused by the subsequent start of the engine 2 can be reduced in a well-balanced manner, and the discomfort given to the driver can be appropriately suppressed. Is possible. Further, such a target motor rotation speed changes according to the gear stage of the transmission 6 and the rotation speed of the motor 4 (initial motor rotation speed) set at the time of requesting the switching of the traveling mode. Therefore, in the present embodiment, the target motor rotation speed changes. , The target motor rotation speed to be set according to the gear stage, the initial motor rotation speed, etc. is set in advance (specified by a map, etc.), and the controller 20 is based on such a preliminary setting, and the current gear stage and Apply the target motor speed according to the initial motor speed.

Further, in the second engine start control, the controller 20 so that the decrease in the rotation speed of the motor 4 ends within an allowable predetermined time (hereinafter, referred to as "allowable rotation speed decrease time") in switching the traveling mode. In addition, control is performed to regenerate the motor 4. The reason for using this permissible rotation speed reduction time is to prevent the switching from the first traveling mode to the second traveling mode to be prolonged, that is, to prevent the engine 2 from being delayed in starting. Therefore, from the viewpoint of suppressing such a delay, the allowable rotation speed reduction time may be set in advance (for example, about 1 second). In addition, the allowable rotation speed reduction time also affects the setting of the target motor rotation speed described above. Therefore, in addition to the gear stage and the initial motor rotation speed described above, it is preferable to set the target motor rotation speed in consideration of the allowable rotation speed reduction time.

Next, the engine start control according to the embodiment of the present invention will be specifically described with reference to FIGS. 4 to 9. FIG. 4 is a flowchart showing the overall processing of engine start control according to the embodiment of the present invention. The entire processing of the engine start control is repeatedly executed by the controller 20 at a predetermined cycle. FIG. 5 is a flowchart showing a first engine start control according to an embodiment of the present invention, which is executed in the entire process of engine start control. FIG. 6 is a flowchart showing a second engine start control according to the embodiment of the present invention, which is executed in the entire process of the engine start control. FIG. 7 is an explanatory diagram of a method of creating a map of a target motor rotation speed according to an embodiment of the present invention. FIG. 8 is an explanatory diagram of the relationship between the pull-in torque due to the engine start and the pull-in torque due to the decrease in the number of revolutions according to the embodiment of the present invention. FIG. 9 is an explanatory diagram of a method of setting a target motor regenerative torque according to a target motor rotation speed according to an embodiment of the present invention.

First, when the overall processing of the engine start control shown in FIG. 4 is started, in step S11, the controller 20 includes various information corresponding to the detection signals from the sensors SN1 to SN6 described above, and various types of the hybrid vehicle 1. Get information. Then, the controller 20 proceeds to step S12.

In step S12, the controller 20 determines whether or not the current travel mode is the first travel mode (EV travel mode). For example, the controller 20 makes the determination based on the control signals output to the motor 4, the first clutch CL1 and the second clutch CL2. In this example, the controller 20 determines that the current travel mode is the first travel mode when the first clutch CL1 is released, the second clutch CL2 is engaged, and the torque is output from the motor 4. To do. When the controller 20 determines that the current traveling mode is the first traveling mode (step S12: Yes), the controller 20 proceeds to step S13. On the other hand, when the controller 20 determines that the current driving mode is not the first driving mode (step S12: No), typically when the current driving mode is the second driving mode, the engine start control Ends the entire processing of. In this case, since the engine 2 is in the operating state, it is not necessary to execute the engine start control to start the engine 2.

In step S13, the controller 20 determines whether or not there is a request to switch from the first traveling mode to the second traveling mode, in other words, whether or not there is a request to start the engine 2. In one example, in the controller 20, the SOC of the battery 5 detected by the SOC sensor SN6 is a predetermined value (for example, the lower limit value of the SOC for which the battery 5 should be charged, which is determined from the viewpoint of protecting the battery 5 or the like. Or, if it is less than (such as SOC in which the power removal of the battery 5 is prohibited), it is determined that there is a request to switch to the second traveling mode. In another example, the controller 20 determines that there is a request to switch to the second travel mode when the air conditioner switch of the hybrid vehicle 1 is turned on by the driver. In yet another example, the controller 20 determines that there is a request to switch to the second travel mode when there is a relatively large acceleration request from the driver (for example, when the accelerator pedal is greatly depressed by the driver). When the controller 20 determines that there is a request for switching from the first traveling mode to the second traveling mode (step S13: Yes), the controller 20 proceeds to step S14. On the other hand, when the controller 20 determines that there is no request for switching from the first traveling mode to the second traveling mode (step S13: No), the controller 20 ends the entire processing of the engine start control. In this case, since the first traveling mode is maintained, it is not necessary to execute the engine start control to start the engine 2.

In step S14, the controller 20 determines whether or not there is an acceleration request from the driver. Specifically, the controller 20 determines the driver's acceleration request by determining whether or not the amount of change in the accelerator opening detected by the accelerator opening sensor SN3 is equal to or greater than a predetermined amount. When the controller 20 determines that there is an acceleration request from the driver (step S14: Yes), the controller 20 proceeds to step S15 and executes the first engine start control. In this case, the controller 20 promptly starts the engine 2 and executes a normal first engine start control in order to prioritize the acceleration request from the driver. On the other hand, when the controller 20 determines that there is no acceleration request from the driver (step S14: No), the controller 20 proceeds to step S16.

In step S16, the controller 20 determines whether or not the motor rotation speed detected by the motor rotation speed sensor SN2 is equal to or higher than a predetermined value. Here, the controller 20 is not in a state in which the state of the motor 4 can generate torque that can start the engine 2 while appropriately suppressing the occurrence of deceleration when switching the traveling mode, based on the motor rotation speed. It is judged whether or not. In a typical example, the controller 20 uses a predetermined value N1 in which the motor 4 can generate a substantially maximum torque (the motor 4 generates a substantially maximum torque below the predetermined value N1) as shown in FIG. Then, make such a judgment. When the controller 20 determines that the motor rotation speed is less than a predetermined value (step S16: No), the controller 20 proceeds to step S15 and executes the first engine start control. In this case, since the motor 4 is already in a state where it can generate sufficient torque, it is not necessary to dare to execute the second engine start control. Therefore, the controller 20 gives priority to starting the engine 2 promptly. Then, the normal first engine start control is executed. On the other hand, when the controller 20 determines that the motor rotation speed is equal to or higher than a predetermined value (step S16: Yes), the controller 20 proceeds to step S17 and executes the second engine start control. The situation in which the process proceeds to step S17 in this way is a situation in which there is no acceleration request from the driver and the motor rotation speed is equal to or higher than a predetermined value when a request for switching from the first running mode to the second running mode is issued. Therefore, the controller 20 executes the second engine start control capable of appropriately suppressing the occurrence of deceleration when the traveling mode is switched.

Next, the first engine start control according to the embodiment of the present invention will be described with reference to FIG. This first engine start control is executed in step S15 of FIG.

When the first engine start control is started, in step S21, the controller 20 applies a torque to the second clutch CL2 when the second clutch CL2 is slipped during the engine start (hereinafter, "the second clutch"). It is called "target slip torque"). Specifically, the controller 20 obtains the second clutch target slip torque based on the gear stage currently set in the transmission 6 and the current torque of the motor 4. Here, the minimum torque applicable to the second clutch CL2 in the slip state (hereinafter referred to as "second clutch minimum torque") is determined according to the gear stage. Therefore, in a typical example, the controller 20 obtains the second clutch minimum torque according to the current gear stage based on the relationship between the gear stage and the second clutch minimum torque (such as a map defined in advance). The minimum torque of the second clutch is set as the target slip torque of the second clutch.

The reason why the minimum torque of the second clutch depends on the gear stage of the transmission 6 is that, as described above, the second clutch CL2 corresponds to a large number of clutches for switching various gear stages in the transmission 6. Because it is. That is, since the clutch constituting the second clutch CL2 changes according to the gear stage, the minimum slip torque due to the second clutch CL2 also changes accordingly.

Next, in step S22, the controller 20 controls the second clutch CL2 so as to gradually shift the second clutch CL2 to the slip state. Specifically, the controller 20 shifts the engaged second clutch CL2 toward the release side until the torque of the second clutch CL2 reaches the second clutch target slip torque set in step S21. I will go. Then, the controller 20 holds the state (slip state) of the second clutch CL2 to which the second clutch target slip torque is applied.

Next, in step S23, the controller 20 controls the first clutch CL1 so as to gradually shift the first clutch CL1 to the slip state. That is, the controller 20 shifts the first clutch CL1 in the released state toward the fastening side. For example, the controller 20 shifts the first clutch CL1 to a predetermined slip state before the complete engagement. Further, the controller 20 shifts the first clutch CL1 to the slip state in this way, transmits the torque of the motor 4 to the engine 2 side via the first clutch CL1, and the torque of the motor 4 causes the engine. Crank 2 to increase the engine speed. In this case, the controller 20 controls to gradually increase the torque of the motor 4 while maintaining the rotation speed of the motor 4. Typically, the controller 20 increases the torque of the motor 4 to the maximum torque that can be output at the current speed. After that, the torque transmitted to the engine 2 side (that is, the torque applied to the first clutch CL1) reaches the torque required for starting the engine 2, but the controller 20 should ignite the engine 2. The first clutch CL1 is held in a predetermined slip state until

Next, in step S24, the controller 20 controls the engine 2 so as to ignite the engine 2 when the timing at which the engine 2 can be ignited is reached. That is, the controller 20 burns the air-fuel mixture in the engine 2 by executing ignition by the spark plug. Then, in step S25, the controller 20 controls the first clutch CL1 so as to completely engage the first clutch CL1 in the slip state. Specifically, the controller 20 completely engages the first clutch CL1 at a timing when the engine speed and the motor speed substantially match. Then, in step S26, the controller 20 controls the second clutch CL2 so as to completely engage the second clutch CL2 in the slip state. Specifically, the controller 20 completely engages the second clutch CL2 at the timing when the engine speed (matching the motor speed) and the speed obtained by converting the vehicle speed into a gear ratio match. Then, the controller 20 ends the first engine start control.

Next, the second engine start control according to the embodiment of the present invention will be described with reference to FIG. This second engine start control is executed in step S17 of FIG.

First, when the second engine start control is started, in step S31, the controller 20 is based on the gear stage currently set in the transmission 6 and the current torque (initial motor rotation speed) of the motor 4. In the second engine start control, the target motor rotation speed at which the rotation speed of the motor 4 should be reduced is set. Then, in step S32, the controller 20 applies the torque to be applied when regenerating the motor 4 based on the target motor rotation speed thus set, the gear stage, and the allowable rotation speed reduction time (hereinafter, "target motor"). It is called "regenerative torque").

Here, each setting method of the target motor rotation speed and the target motor regenerative torque will be specifically described with reference to FIGS. 7 to 9. First, with reference to FIG. 7, a method of creating a map used for setting a target motor rotation speed will be described. As shown in FIG. 7, the map of the target motor rotation speed is created by obtaining each of the pull-in torque due to the engine start and the pull-in torque due to the decrease in the rotation speed, and then comparing these pull-in torques.

Specifically, the pull-in torque due to engine start is the minimum torque of the second clutch according to the gear stage of the transmission 6 and the candidate of the target motor rotation speed to be applied to the motor 4 (hereinafter, "target motor rotation speed candidate"). The maximum motor torque (determined by the characteristics of FIG. 2) according to (referred to as) and the torque required to start the engine 2 (hereinafter referred to as "engine starting torque". The engine starting torque is the resistance of the engine 2). And the variation of the first clutch CL1 and the loss in the transmission 6). Basically, the difference between the sum of the minimum torque and the maximum motor torque of the second clutch and the engine starting torque is the pull-in torque due to the engine starting.

On the other hand, the pull-in torque due to the decrease in the rotation speed is obtained based on the inertia of the second clutch CL2 according to the gear stage of the transmission 6, the initial motor rotation speed, the target motor rotation speed candidate, and the allowable rotation speed decrease time. Be done. Here, due to the inertia of the second clutch CL2 according to the gear stage of the transmission 6, the torque for traveling of the hybrid vehicle 1 is drawn in with the rotation fluctuation of the planetary gear in the transmission 6 when the traveling mode is switched. (Things that lead to vehicle deceleration) occur. Therefore, the rotation speed is reduced based on the torque drawn by the inertia of the second clutch CL2 and the torque for changing the motor rotation speed from the initial motor rotation speed to the target motor rotation speed candidate in the allowable rotation speed reduction time. The pull-in torque is required. The inertia of the second clutch CL2 depends on the gear stage of the transmission 6, as described above, the second clutch CL2 corresponds to a large number of clutches for switching various gear stages in the transmission 6. Because it is a thing.

The relationship between the pull-in torque due to the engine start and the pull-in torque due to the decrease in the number of revolutions obtained in this way is as shown in FIG. In FIG. 8, the target motor rotation speed candidate is shown on the horizontal axis, and the pull-in torque is shown on the vertical axis. The solid line graph shows the pull-in torque due to the engine start, and the broken line graph shows the pull-in torque due to the decrease in the number of revolutions. As shown in FIG. 8, as the target motor rotation speed candidate becomes larger, the pull-in torque due to the engine start becomes larger, while the pull-in torque due to the decrease in the rotation speed becomes smaller. In other words, the smaller the target motor rotation speed candidate, the smaller the pull-in torque due to engine start, while the larger the pull-in torque due to the decrease in rotation speed. From this, it can be said that the pull-in torque due to the engine start and the pull-in torque due to the decrease in the rotation speed have a trade-off relationship with the change in the target motor rotation speed candidate.

In the present embodiment, the target motor rotation speed candidate that minimizes the total of the pull-in torque due to the engine start and the pull-in torque due to the decrease in the rotation speed is set as the target motor rotation speed. In a typical example, a target motor rotation speed candidate at a point P1 where a graph showing a pull-in torque due to engine start and a graph showing a pull-in torque due to a decrease in rotation speed intersect is set as a target motor rotation speed. Since such a target motor rotation speed changes according to the gear stage of the transmission 6 and the initial motor rotation speed of the motor 4, in the present embodiment, it is applied to each of various gear stages and various initial motor rotation speeds. The target motor speed to be used is specified. In particular, a three-dimensional map is created in which the target motor rotation speed to be applied is associated with each gear stage and each initial motor rotation speed. This map is stored in the memory of the controller 20.

Using such a map, as shown in FIG. 9, the target motor rotation speed is set, and the target motor regenerative torque corresponding to the target motor rotation speed is set. First, the controller 20 sets the target motor rotation speed corresponding to the current gear stage and the initial motor rotation speed with reference to the map of the target motor rotation speed. Then, the controller 20 reduces the rotation speed by the same method as described above based on the target motor rotation speed, the inertia of the second clutch CL2 according to the gear stage of the transmission 6, and the allowable rotation speed reduction time. Find the pull-in torque. The pull-in torque due to the decrease in the number of revolutions is an acceptable pull-in torque that is balanced with the pull-in torque that occurs after the engine is started. Then, the controller 20 sets a target motor regenerative torque (negative torque) to be applied when the motor 4 is regenerated, based on the pull-in torque due to such a decrease in the number of revolutions.

Here, an example of setting the target motor regenerative torque is shown on the assumption that the torque of the motor 4 is controlled. In another example, when the motor rotation speed is controlled instead of the torque of the motor 4, the target of the reduction rate (decrease inclination) of the rotation speed applied when the motor 4 is regenerated instead of the target motor regeneration torque. The value may be set based on the pull-in torque due to the decrease in the number of rotations. Further, in the above-mentioned example, an example in which a map of the target motor rotation speed defined by the gear stage and the initial motor rotation speed is used is shown, but in other examples, the gear stage and the initial speed are used without using such a map. A coefficient for obtaining the target motor rotation speed from the motor rotation speed may be used. In this example, the coefficient corresponding to the gear stage and the initial motor rotation speed is specified in advance, and the controller 20 determines the coefficient corresponding to the current gear stage and the initial motor rotation speed based on this specification. , The target motor rotation speed may be set by multiplying this coefficient by the initial motor rotation speed.

Returning to FIG. 6, the processing after step S33 after steps S31 and S32 will be described. In step S33, the controller 20 sets the second clutch target slip torque. For example, the controller 20 sets the second clutch target slip torque based on the second clutch minimum torque according to the gear stage of the transmission 6 and the target motor regeneration torque set in step S32. In this example, when the target motor regeneration torque is less than the second clutch minimum torque, the controller 20 sets the second clutch minimum torque as the second clutch target slip torque, while the target motor regeneration torque is the second. If it is equal to or greater than the minimum clutch torque, the target motor regeneration torque is set as the second clutch target slip torque.

Next, in step S34, the controller 20 controls the second clutch CL2 so as to gradually shift the second clutch CL2 to the slip state. Specifically, the controller 20 shifts the engaged second clutch CL2 toward the release side until the torque of the second clutch CL2 reaches the second clutch target slip torque set in step S33. I will go. Then, the controller 20 holds the state (slip state) of the second clutch CL2 to which the second clutch target slip torque is applied.

Next, in step S35, the controller 20 controls to regenerate the motor 4 so as to reduce the motor rotation speed. Specifically, the controller 20 reduces the rotation speed of the motor 4 to the target motor rotation speed by controlling the motor 4 to apply the target motor regenerative torque set in step S32. The controller 20 continues the control of applying the target motor regeneration torque to the motor 4 until the motor rotation speed reaches the target motor rotation speed, and when the motor rotation speed reaches the target motor rotation speed, the target motor regeneration torque is applied to the motor 4 Terminate the control given to. After that, in the subsequent processing (step S36), the controller 20 controls to increase the torque of the motor 4 in order to crank the engine 2 (in this case, power runs from the control to regenerate the motor 4). Can be switched to control). If the motor rotation speed does not reach the target motor rotation speed within the permissible rotation speed reduction time (for example, within 1 second), the controller 20 applies the target motor regeneration torque when the permissible rotation speed reduction time elapses. The control given to the motor 4 may be terminated.

Next, the controller 20 performs the processes of steps S36 to S39. Since the processes of steps S36 to S39 are the same as the processes of steps S23 to S26 in the first engine start control shown in FIG. 5, the description thereof will be omitted. The controller 20 ends the second engine start control after step S39.

<Effect>
Next, the operation and effect of the control device for the hybrid vehicle according to the embodiment of the present invention will be described.

FIG. 10 is an example of a time chart showing time changes of various parameters when the engine start control according to the embodiment of the present invention is executed. The time chart of FIG. 10 shows, in order from the top, the acceleration (including deceleration) of the hybrid vehicle 1, the rotation speed of the motor 4 and the engine 2, and the torque of the motor 4 and the engine 2 (specifically, the output shaft of the motor 4). (Torque in) is shown.

Here, in order to explain the operation and configuration of the second engine start control according to the present embodiment, in addition to the result when the second engine start control is performed, the result when the first engine start control is performed is compared. It is shown as an example. Each graph in FIG. 10 shows the time change of the following parameters.
-Graph G11: Acceleration by second engine start control-Graph G12: Acceleration by first engine start control-Graph G21: Rotation speed of motor 4 by second engine start control-Graph G22: Motor 4 by first engine start control Number of revolutions ・ Graph G23: Number of revolutions of engine 2 ・ Graph G24: Number of revolutions converted from vehicle speed to gear ratio ・ Graph G31: Torque of motor 4 by second engine start control ・ Graph G32: Motor 4 by first engine start control Torque graph G33: Torque applied to the first clutch CL1 (corresponding to the torque applied to start the engine 2)
-Graph G34: Torque applied to the second clutch CL2-Graph G35: Combustion torque of the engine 2 Graphs G23, G24, G33, and G35 are common to the first engine start control and the second engine start control. is there. That is, the change of each parameter shown in the graphs G23, G24, G33, and G35 is the same in the first engine start control and the second engine start control.

Before time t1, a request for switching from the first running mode to the second running mode (in other words, a request for starting the engine 2 in the first running mode) is issued, and the second clutch CL2 in the engaged state is in the slip state. It is assumed that it has been migrated. Then, from time t1 to time t2, the motor 4 is regenerated in the second engine start control, and specifically, the torque applied to the motor 4 is set to a predetermined negative torque (target motor regenerative torque). (See graph G31), which reduces the rotation speed of the motor 4 (see graph G21). In this case, the pull-in torque generated by the above-mentioned decrease in the number of revolutions causes a relatively small deceleration as shown by the arrow A1 in FIG. 10 in the hybrid vehicle 1 (see graph G11). On the other hand, in the first engine start control, the rotation speed and torque of the motor 4 are maintained substantially constant from time t1 to time t2 (see graphs G22 and G32), and deceleration does not occur in the hybrid vehicle 1 (graph). See G12). The magnitude of the torque of the motor 4 between the time t1 and the time t2 in the first engine start control corresponds to the running torque for running the hybrid vehicle 1 at a constant speed.

Then, at time t2, in both the first and second engine start control, the first clutch CL1 in the released state is shifted to the slip state, and the torque of the motor 4 is started to increase in order to crank the engine 2. (See graphs G31 and G32), which causes the engine speed to begin to rise (see graph G23). After that, in the first engine start control, at time t3, the torque of the motor 4 becomes less than the torque obtained by adding the torque of the first clutch CL1 and the torque for running. That is, the torque of the motor 4 cannot cover the torque required to start the engine 2. As a result, at time t3, the pull-in torque generated by starting the engine described above is generated, so that the hybrid vehicle 1 starts to decelerate (see graph G12). After that, in the first engine start control, at time t5, the torque of the first clutch CL1 reaches the torque required to start the engine 2, but at this time, the maximum pull-in torque is generated. As a result, in the first engine start control, a relatively large deceleration as shown by the arrow A3 in FIG. 10 occurs at time t5 (see graph G12).

On the other hand, in the second engine start control, the torque of the motor 4 becomes lower than the torque obtained by adding the torque of the first clutch CL1 and the torque for traveling at the time t4 after the above time t3. That is, in the second engine start control, the motor rotation speed is temporarily lowered before the torque increase of the motor 4 for cranking, so that the motor 4 can generate a larger torque than the first engine start control. (Because the maximum torque that can be generated by the motor 4 is larger than that of the first engine start control), the torque required to start the engine 2 can be covered by the torque of the motor 4 for a long period of time. It became. In the second engine start control, deceleration starts to occur in the hybrid vehicle 1 due to the pull-in torque generated by starting the engine at such time t4 (see graph G11). After that, in the second engine start control, at time t5, the torque of the first clutch CL1 reaches the torque required to start the engine 2, and the maximum pull-in torque is generated. As a result, the arrow A2 in FIG. Deceleration as shown in (see Graph G11) occurs. It can be seen that the deceleration that occurs during the start of the engine 2 in such second engine start control is considerably smaller than the deceleration that occurs during the start of the engine 2 in the first engine start control.

Here, in the second engine start control, the deceleration due to the pull-in torque due to the decrease in the number of revolutions (see arrow A1) and the deceleration due to the pull-in torque due to the engine start (see arrow A2) are decelerated twice. Although it occurs, the magnitude of each of these decelerations is smaller than the deceleration caused by the pull-in torque due to the engine start in the first engine start control (see arrow A3). Therefore, according to the second engine start control, as compared with the first engine start control, the discomfort given to the driver due to the occurrence of deceleration when switching from the first running mode to the second running mode is effectively suppressed. be able to. In the first engine start control, only one deceleration (deceleration due to the pull-in torque due to engine start) occurs, but since this deceleration is relatively large, the driver tends to feel uncomfortable.

After the above time t5, in both the first and second engine start control, the engine 2 is ignited at the time t6, and then, at the time t7 when the engine speed and the motor speed match, the first clutch CL1 is completely engaged, and then the second clutch CL2 is completely engaged at time t8 when the engine speed and the rotation speed obtained by converting the vehicle speed into gear ratios coincide. As a result, the traveling mode of the hybrid vehicle 1 is switched to the second traveling mode.

As described above, in the present embodiment, when switching from the first traveling mode to the second traveling mode, the controller 20 controls to regenerate the motor 4 so as to reduce the motor rotation speed, and then the second operation is performed. 1 The clutch CL1 is shifted from the released state to the engaged state, and the engine 2 is cranked by the motor 4 to start the engine 2. That is, in the present embodiment, when switching from the first traveling mode to the second traveling mode, the controller 20 controls to regenerate the motor 4 before starting the engine 2 to temporarily reduce the motor rotation speed. Keep it.

As a result, when the engine 2 is started to switch the traveling mode, a relatively large torque can be generated from the motor 4, so that the torque required to start the engine 2 is the torque of the motor 4. Will be able to be realized effectively. Specifically, the torque of the motor 4 makes it possible to realize most of the torque required to start the engine 2. As a result, the traveling torque of the hybrid vehicle 1 can be suppressed as much as possible from being used for starting the engine 2, and the deceleration generated in the hybrid vehicle 1 can be appropriately reduced. Therefore, it is possible to appropriately suppress the discomfort given to the driver when switching from the first traveling mode to the second traveling mode.

Further, according to the present embodiment, the controller 20 sets the motor rotation speed when the driver requests to accelerate the hybrid vehicle 1 even when switching from the first traveling mode to the second traveling mode. The control to regenerate the motor 4 for lowering is not performed. As a result, the engine 2 can be started quickly, and the acceleration request from the driver can be appropriately realized.

Further, according to the present embodiment, the controller 20 has a motor rotation speed that allows the motor 4 to generate torque equal to or higher than a predetermined value even when switching from the first traveling mode to the second traveling mode. When it is within the range of, the control for regenerating the motor 4 for lowering the motor rotation speed is not performed. In this case, since the motor 4 is already in a state where it can generate sufficient torque, it is not necessary to dare to execute the second engine start control. Therefore, by preventing the motor 4 from being regenerated when the traveling mode is switched as described above, the prompt start of the engine 2 can be appropriately prioritized.

Further, according to the present embodiment, the controller 20 reduces the rotation speed of the motor 4 by regeneration based on the current gear stage of the transmission 6 and the current rotation speed of the motor 4 (initial motor rotation speed). Since the target rotation speed to be set is set, it is possible to appropriately suppress the pull-in of the running torque generated at the time of switching from the first running mode to the second running mode.

In particular, according to the present embodiment, the controller 20 has a target rotation based on the pull-in torque due to the engine start and the pull-in torque due to the decrease in the rotation speed according to the current gear stage and the current rotation speed (initial motor rotation speed). Since the number is set, both the deceleration caused by the decrease in the rotation speed of the motor 4 and the deceleration caused by the start of the engine 2 can be reduced in a well-balanced manner, and the discomfort given to the driver can be appropriately suppressed. It becomes.

Further, according to the present embodiment, the controller 20 controls to regenerate the motor 4 so that the decrease in the rotation speed of the motor 4 ends within an acceptable predetermined time in the switching of the traveling mode. It is possible to appropriately suppress that the switching from the traveling mode to the second traveling mode is prolonged, that is, the start of the engine 2 is delayed.

Further, according to the present embodiment, when switching from the first traveling mode to the second traveling mode, the controller 20 shifts the second clutch CL2 from the engaged state to the slip state before regenerating the motor 4. Control to make it. As a result, the traveling torque of the hybrid vehicle 1 is suppressed as much as possible from being transmitted to the motor 4 and the engine 2 side via the second clutch CL2, and the occurrence of deceleration when switching the traveling mode is reduced. At the same time, the second clutch CL2 can be completely engaged after the engine 2 is started.

Further, the present embodiment is applied to a hybrid vehicle 1 including a transmission 6 (automatic transmission) including planetary gears. Since the transmission 6 (automatic transmission) equipped with planetary gears has a large inertia, it is easy for torque for traveling to be drawn when switching the traveling mode as described above, but a hybrid equipped with such a transmission 6 By applying the second engine start control according to the present embodiment to the vehicle 1, it is possible to appropriately suppress the occurrence of deceleration due to the pulling of torque for traveling.

1 Hybrid vehicle 2 Engine 4 Motor 6 Transmission 12 Drive wheel 20 Controller 20a Driving mode judgment unit 20b Motor control unit 20c Clutch control unit 20d Cranking control unit CL1 1st clutch CL2 2nd clutch

Claims (9)

A control device for a hybrid vehicle having an engine, a motor, and a clutch for switching between transmission and interruption of torque between the engine and the motor.
From the first traveling mode in which the clutch is set to the released state and the hybrid vehicle is driven by using the torque of the motor without using the torque of the engine, the clutch is set to the engaged state and at least the engine. A traveling mode determining means for determining whether or not to switch the traveling mode of the hybrid vehicle to the second traveling mode in which the hybrid vehicle is driven by using the torque of the above.
Control to regenerate the motor so as to reduce the rotation speed of the motor when it is determined by the traveling mode determining means that the traveling mode of the hybrid vehicle is switched from the first traveling mode to the second traveling mode. Motor control means to perform
After the control by the motor control means, the clutch control means for shifting the clutch from the released state to the engaged state so that the torque of the motor is transmitted to the engine via the clutch.
A cranking control means for cranking the engine by the motor to start the engine during and / or after control by the clutch control means.
A control device for a hybrid vehicle, characterized in that it has. When the motor control means determines that the traveling mode of the hybrid vehicle is switched from the first traveling mode to the second traveling mode by the traveling mode determining means, the driver requests that the hybrid vehicle be accelerated. The control of the hybrid vehicle according to claim 1, wherein in some cases, the control for regenerating the motor is not performed, and when there is no request from the driver to accelerate the hybrid vehicle, the control for regenerating the motor is performed. apparatus. When the motor control means determines that the traveling mode of the hybrid vehicle is switched from the first traveling mode to the second traveling mode by the traveling mode determining means, the rotation speed of the motor is determined by the motor. If the torque is within the range of the rotation speed that can generate the torque of a predetermined value or more, the motor is not controlled to regenerate, and if the rotation speed of the motor is not within the range, the motor is regenerated. The control device for a hybrid vehicle according to claim 1 or 2, wherein the control is performed. The hybrid vehicle further comprises a transmission provided on a power transmission path between the engine and the motor and the drive wheels.
When the motor control means determines by the traveling mode determining means that the traveling mode of the hybrid vehicle is switched from the first traveling mode to the second traveling mode, the motor control means and the current gear stage of the transmission. Based on the current rotation speed of the motor, the target rotation speed at which the rotation speed of the motor should be reduced by the regeneration is set, and the motor is regenerated so as to reduce the rotation speed of the motor to the target rotation speed. The control device for a hybrid vehicle according to any one of claims 1 to 3, which controls the operation. The motor control means decreases due to the torque of the hybrid vehicle that decreases due to the start of the engine and the decrease in the rotation speed of the motor according to the current gear stage and the current rotation speed. The hybrid vehicle control device according to claim 4, wherein the target rotation speed is set based on the torque of the hybrid vehicle. Any one of claims 1 to 5, wherein the motor control means controls to regenerate the motor so that the decrease in the rotation speed of the motor ends within an acceptable predetermined time in switching the traveling mode. The hybrid vehicle control device described in the section. When the clutch that switches between the transmission and disconnection of torque between the engine and the motor is the first clutch, in the hybrid vehicle, in addition to the first clutch, between the engine and the motor and the drive wheels. Further has a second clutch that switches between torque transmission and interruption in
When the clutch control means determines that the travel mode of the hybrid vehicle is switched from the first travel mode to the second travel mode by the travel mode determining means, the clutch control means is described before being controlled by the motor control means. The control device for a hybrid vehicle according to any one of claims 1 to 6, which controls the transition of the second clutch from the engaged state to the slip state. The hybrid according to any one of claims 1 to 7, wherein the hybrid vehicle is provided on a power transmission path between the engine and the motor and a drive wheel, and further includes an automatic transmission including planetary gears. Vehicle control device. The control device for a hybrid vehicle according to any one of claims 1 to 8, wherein the motor has a characteristic that the torque generated decreases as the number of rotations increases.

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