JP2018177084A - Control method of hybrid vehicle and control device of hybrid vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control method of a hybrid vehicle which prevents the large reduction of vehicle deceleration when coast regeneration torque is limited at coast traveling, and can prevent an incongruity of a driver.SOLUTION: An engine Eng is removed from a drive system at coast traveling at which a vehicle travels with an accelerator opening set in a release operation region, and coast regeneration torque generated at a motor generator MG is set to target regeneration torque. When a prescribed regeneration limit condition is established at the low-return gear change control of a continuously variable transmission CVT during the coast traveling, a regeneration torque upper limit value is limited to a value smaller than a regeneration torque maximum value which can be generated at the motor generator MG. Also, by compensating for a lowering amount of the coast regeneration torque caused by the limit of the regeneration torque upper limit value by engine friction torque, a gear change ratio when a variation width of vehicle deceleration is brought into an allowable range is set to a prescribed gear change ratio. Then, a first clutch CL1 is fastened in a period that the gear change ratio reaches the prescribed gear change ratio after a start of the limit of the regeneration torque upper limit value.SELECTED DRAWING: Figure 7

Description

  The present disclosure relates to a control method and control device for a hybrid vehicle.

  Conventionally, when it is not possible to output the vehicle deceleration according to the request only by the regenerative torque generated by the motor generator due to the regenerative limitation etc., a control method of a hybrid vehicle is known in which the vehicle deceleration is compensated by the friction torque of the engine. (See, for example, Patent Document 1).

JP 2012-218697 A

  However, if it is determined that the necessary vehicle deceleration can not be output only by the regenerative torque, and then the engine is connected to the drive wheels and the vehicle friction is compensated for by the engine friction torque, the compensation of the vehicle deceleration is delayed. Therefore, the reduction range of the vehicle deceleration due to the regeneration limitation is increased, and a so-called G level difference is generated, which causes a problem of giving a sense of discomfort to the driver. In particular, during coasting traveling in a state where the operation amount of the accelerator pedal is substantially zero, the driver is likely to feel fluctuation of the vehicle deceleration, so it is necessary to appropriately suppress the deceleration reduction width.

  The present disclosure has been made in view of the above problems, and a control method of a hybrid vehicle and a control device of a hybrid vehicle capable of preventing a significant reduction in vehicle deceleration accompanying limitation of regenerative torque during coasting. Intended to be provided.

To achieve the above object, the present disclosure comprises an engine, a motor generator, an automatic transmission disposed between the engine and the drive wheels, and an engine clutch disposed between the engine and the automatic transmission. And a control method of a hybrid vehicle in which the engine clutch is engaged to connect the engine to the drive wheels through the automatic transmission, and the engine clutch is released to disconnect the engine from the drive wheels.
During coasting by accelerator release operation, the engine clutch is released to disconnect the engine from the drive wheels, and the coast regeneration torque generated by the motor generator is used as the target regeneration torque.
Further, at the time of low return shift control for returning the gear ratio of the automatic transmission during coasting to the lowest gear ratio, the motor generator can generate the upper limit value of the coast regeneration torque when a predetermined regeneration limitation condition is satisfied. Limit to a value smaller than the maximum value of regenerative torque.
Furthermore, while limiting the upper limit value of the coasting regenerative torque, the reduction ratio of the coasting regenerative torque is compensated with the engine friction torque to compensate the reduction of the coasting regenerative torque with the engine friction torque. Set to ratio.
Then, the engine clutch is engaged until the gear ratio of the automatic transmission reaches a predetermined gear ratio after the restriction of the upper limit value of the coast regenerative torque is started.

  Therefore, in the present disclosure, it is possible to prevent a significant reduction in the vehicle deceleration accompanying the limitation of the regenerative torque during coasting.

FIG. 1 is an entire configuration diagram showing an FF hybrid vehicle to which a control method and a control device of a hybrid vehicle of a first embodiment are applied. FIG. 7 is a diagram showing an example of a mode transition map used in the first embodiment. FIG. 7 is a diagram showing an example of a shift schedule map used in the first embodiment. FIG. 6 is a block diagram showing a configuration of a coasting clutch control unit of the first embodiment. FIG. 7 is a view showing an example of a necessary deceleration setting map used in the first embodiment. FIG. 6 is a view showing an example of an engine rotational speed upper limit value setting map used in the first embodiment. 5 is a flowchart showing the flow of a clutch control process performed in the first embodiment. FIG. 6 is a flowchart showing a flow of a coasting fuel cut processing configuration executed in the first embodiment; FIG. Vehicle speed, accelerator opening degree, gear ratio, brake depression force, 1st clutch command, coast regenerative torque, regenerative torque upper limit value, engine friction torque, driving wheel deceleration torque when motor regenerative restriction occurs during coasting in Example 1. It is a time chart which shows each characteristic of. FIG. 7 is a time chart showing the characteristics of the motor rotational speed, engine rotational speed, vehicle deceleration, fuel cut flag, fuel cut prohibition flag, and fuel cut state when motor regeneration restriction occurs during coasting in Example 1. FIG.

  Hereinafter, an embodiment of a control method and a control device for a hybrid vehicle of the present disclosure will be described based on Example 1 shown in the drawings.

Example 1
First, the configuration will be described.
The control method and control device for a hybrid vehicle in the first embodiment is applied to an FF hybrid vehicle provided with a parallel hybrid drive system called a one-motor two-clutch. Hereinafter, the configuration of the FF hybrid vehicle to which the control method and the control device of the first embodiment are applied will be described as "detailed configuration of drive system", "detailed configuration of driving mode", "detailed configuration of control system", "coast clutch The control processing configuration and the coasting fuel cut processing configuration will be described separately.

[Detailed configuration of drive system]
As shown in FIG. 1, the drive system of the FF hybrid vehicle includes an engine Eng, a first clutch CL1 (engine clutch), a motor generator MG, a second clutch CL2, and a continuously variable transmission CVT (automatic transmission). , A final gear FG, a left drive wheel LT, and a right drive wheel RT.

  The engine Eng is torque-controlled so that the engine torque matches the command value by controlling the intake air amount by the throttle actuator, the fuel injection amount by the injector, and the ignition timing by the spark plug. When the engine Eng is not in the combustion operation state but in the fuel cut state (fuel supply stop) and in the cranking operation state in which the first clutch CL1 is engaged, the engine friction torque due to the frictional sliding resistance between the piston and the cylinder inner wall Generate.

  The first clutch CL1 is interposed at a position between the engine Eng and the motor generator MG, and corresponds to an engine clutch disposed between the engine Eng and the left and right driving wheels LT and RT. For example, a normally open dry multi-plate clutch or the like is used as the first clutch CL1, and engagement / slip engagement / disengagement between the engine Eng and the motor generator MG is performed. When the first clutch CL1 is in the engaged state, the engine Eng is connected to the left and right driving wheels LT and RT, and the motor torque + the engine torque is transmitted to the second clutch CL2. When the first clutch CL1 is in the released state, the engine Eng is disconnected from the left and right drive wheels LT and RT, and only the motor torque is transmitted to the second clutch CL2. The engagement / slip engagement / disengagement of the first clutch CL1 is performed by hydraulic control in which a transmission torque (clutch torque capacity) is generated in accordance with the clutch hydraulic pressure (pressing force).

  The motor generator MG has an AC synchronous motor structure and performs motor torque control and motor rotational speed control at the time of starting and traveling, and performs recovery (charging) of vehicle kinetic energy to the battery 9 by regenerative brake control at the time of deceleration. It is.

  The second clutch CL2 is a normally open wet multi-plate clutch or wet multi-disc brake provided in the forward / reverse switching mechanism of the continuously variable transmission CVT, and the transmission torque (clutch torque capacity) according to clutch hydraulic pressure (pressing force) ) Occurs. The second clutch CL2 transmits torques output from the engine Eng and the motor generator MG (when the first clutch CL1 is engaged) to the left and right drive wheels LT and RT via the continuously variable transmission CVT and the final gear FG. Communicate with. The second clutch CL2 is, as shown in FIG. 1, set to a position between the continuously variable transmission CVT and the left and right drive wheels LT and RT, other than being set to a position between the motor generator MG and the continuously variable transmission CVT. It may be set to

  The continuously variable transmission CVT has a primary pulley PrP connected to a transmission input shaft input, a secondary pulley SeP connected to a transmission output shaft output, and a pulley belt bridged between the primary pulley PrP and the secondary pulley SeP. It is a belt type continuously variable transmission which has BE.

  The primary pulley PrP has a fixed sheave fixed to a transmission input shaft input and a movable sheave slidably supported on the transmission input shaft input. The secondary pulley SeP has a fixed sheave fixed to the transmission output shaft output, and a movable sheave slidably supported on the transmission output shaft output.

  The pulley belt BE is a metal belt wound around the primary pulley PrP and the secondary pulley SeP, and is held between the fixed sheave and the movable sheave. Here, as the pulley belt BE, a pin type belt or a VDT type belt is used.

  In the continuously variable transmission CVT, the pulley widths of the two pulleys PrP and SeP are changed, and the diameter of the clamping surface of the pulley belt BE is changed to freely control the transmission ratio (pulley ratio). Here, when the pulley width of the primary pulley PrP widens and the pulley width of the secondary pulley SeP narrows, the transmission gear ratio changes to the low side. Further, when the pulley width of the primary pulley PrP is narrowed and the pulley width of the secondary pulley SeP is widened, the transmission gear ratio is changed to the High side.

[Detailed configuration of operation mode]
The FF hybrid vehicle of Example 1 has an electric travel mode (hereinafter referred to as "EV mode"), a hybrid travel mode (hereinafter referred to as "HEV mode"), and the like as an operation mode by the above-described drive system. .

  In the "EV mode", the first clutch CL1 is in the released state, the second clutch CL2 is in the engaged state, the engine Eng is disconnected from the drive system, and the drive power can be transmitted only to the motor generator MG. , Connect to RT. Thus, in the "EV mode", during drive travel for applying a driving force to the vehicle, motor generator MG is controlled to the power running side, and motor generator MG is used as a travel drive source (motor). Further, at the time of decelerating travel for applying a braking force to the vehicle, the motor generator MG is controlled to the regeneration side to be used as a power generation drive source (generator), and the regenerative torque generated at this time is used as the braking force.

  Note that “control the motor generator MG to the power running side” means that the motor generator is supplied with electric power from the inverter 8 to the motor generator MG so that the motor generator MG is in a power running state to drive the left and right drive wheels LT, RT. It is to control MG. Further, “control the motor generator MG to the regeneration side” controls the motor generator MG such that the rotational energy possessed by the motor generator MG and the left and right drive wheels LT and RT is in a regenerative state flowing into the inverter 8. It is.

  In the "HEV mode", the first clutch CL1 is engaged, the second clutch CL2 is engaged, and both the motor generator MG and the engine Eng are connected to the left and right drive wheels LT and RT so that driving force can be transmitted. . Thus, in the "HEV mode", during drive travel, the motor generator MG is controlled to the power running side and fuel is supplied to the engine Eng, and the engine Eng and the motor generator MG are used as a travel drive source. Further, at the time of decelerating traveling, the motor generator MG is controlled to the regeneration side, and the regenerative torque generated at this time is used as the braking force. Further, at the time of deceleration, the engine Eng is brought into a cranking operation state (rotating with the motor generator MG) to generate friction torque, and friction torque (engine friction torque) by the engine Eng is used as a braking force.

Mode transition of “EV mode” and “HEV mode” is performed using the target driving force and the mode transition map shown in FIG. That is, during driving travel, a positive value target driving force (required acceleration) and an operating point P according to the vehicle speed are set on the powering control area set above the target driving force zero axis shown in FIG. The "EV mode" is selected when the operating point P is in the EV region, and the "HEV mode" is selected when the operating point P is in the HEV region. Further, during deceleration traveling, an operating point P according to the target driving force (requested deceleration) of a negative value is set on the regeneration control region set lower than the target driving force zero axis shown in FIG. The "EV mode" is selected when the operating point P is in the EV region, and the "HEV mode" is selected when the operating point P is in the HEV region.
The target driving force is calculated based on the vehicle speed and the driver's driving operation (here, the accelerator opening degree and the brake depression force), the target vehicle speed and the actual vehicle speed.

[Detailed configuration of control system]
As shown in FIG. 1, the control system of the FF hybrid vehicle includes an integrated controller 14, a transmission controller 15, a clutch controller 16, an engine controller 17, a motor controller 18, and a battery controller 19. . Then, as the sensors, the motor rotational speed sensor 6, the transmission input rotational speed sensor 7, the accelerator opening degree sensor 10, the engine rotational speed sensor 11, the oil temperature sensor 12, and the transmission output rotational speed sensor 13 And. Furthermore, a brake sensor 21, a lever position sensor 22, and a vehicle speed sensor 23 are provided.

  The integrated controller 14 calculates a target driving force from the battery state, the accelerator opening degree, the vehicle speed (a value synchronized with the transmission output rotational speed), the hydraulic oil temperature and the like. Then, based on the calculation result of the target driving force, the command value for each actuator (motor generator MG, engine Eng, first clutch CL1, second clutch CL2, continuously variable transmission CVT) is calculated, and via CAN communication line 25 To each controller 15, 16, 17, 18, 19.

  The transmission controller 15 (gear shift control unit) controls the gear shift by controlling the pulley hydraulic pressure supplied to the primary pulley PrP and the secondary pulley SeP of the continuously variable transmission CVT so as to achieve the gear shift command from the integrated controller 14 Do.

  The shift control by the transmission controller 15 uses the shift schedule map shown in FIG. 3 and an operating point based on the vehicle speed VSP and the target driving force DF (absolute value of required acceleration or required deceleration) to drive on the shift schedule. This is performed by determining the target primary rotational speed Npri * by the point (VSP, DF). As shown in FIG. 3, according to the operating point (VSP, DF), the transmission schedule changes the transmission ratio within the transmission ratio range of the lowest transmission ratio and the highest transmission ratio according to the operating point (VSP, DF). The thick line in FIG. 3 indicates a coast shift line indicating a transmission gear ratio during coasting, and when a coast determination signal from the coast determination unit 31 described later is input, the driving point (VSP, DF) is determined according to the vehicle speed. Move along the coasting shift line to determine the target primary speed Npri *. In addition, when the vehicle speed VSP decreases and decreases to the first vehicle speed VSPα, the downshift is started from the highest gear ratio to the lowest gear ratio. The shift control for downshifting from the highest gear ratio to the lowest gear ratio is the low return shift control for returning the gear ratio of the continuously variable transmission CVT to the lowest gear ratio. This low return shift control is continued until the vehicle speed decreases to the second vehicle speed VSPβ. When the vehicle speed falls below VSPβ, the transmission gear ratio is fixed to the lowest transmission gear ratio.

  The clutch controller 16 inputs sensor information from the engine speed sensor 11, the motor speed sensor 6, the transmission input speed sensor 7, etc., and outputs a clutch hydraulic pressure command value to the first clutch CL1 and the second clutch CL2. Do. Thus, the pressing force of the first clutch CL1 is set, and the pressing force of the second clutch CL2 is set.

  The engine controller 17 inputs sensor information from the engine speed sensor 11 and performs torque control of the engine Eng so as to achieve an engine torque command value from the integrated controller 14. In addition, when the fuel cut command is input from the integrated controller 14, the fuel supply to the engine Eng is stopped.

The motor controller 18 outputs a control command to the inverter 8 so as to achieve the motor torque command value, the motor rotation speed command value, and the regenerative force command from the integrated controller 14, and the motor torque control or motor rotation of the motor generator MG. Performs number control and regenerative brake control. The motor controller 18 also manages the motor generator temperature and transmits motor temperature information to the integrated controller 14.
In addition, inverter 8 performs mutual conversion between direct current and alternating current, and when motor generator MG is controlled to the power running side, the discharge current from battery 9 is changed to the drive current of motor generator MG to regenerate motor generator MG. When controlling to the side, the generated current from motor generator MG is converted to a charging current for battery 9.

  The battery controller 19 manages the charge capacity SOC of the battery 9 and the battery temperature, and transmits SOC information and battery temperature information to the integrated controller 14.

  Furthermore, in the first embodiment, the integrated controller 14 (control device for a hybrid vehicle) includes the coasting clutch control unit 30 and the coasting fuel supply control unit 40.

  The coast time clutch control unit 30 releases the first clutch CL1 to separate the engine Eng from the left and right drive wheels LT and RT and causes the motor generator MG to generate regenerative torque (coast regenerative torque) during coasting. In addition, regenerative braking control is performed to make this coast regenerative torque the target regenerative torque. And, while coasting, while performing low return shift control to shift the continuously variable transmission CVT toward the lowest Low gear ratio, if a predetermined regeneration limitation condition is satisfied, the upper limit value of the coast regeneration torque (regeneration torque upper limit Value) is limited to a value smaller than the maximum value (regeneration torque maximum value) of the regeneration torque that can be generated by motor generator MG. Furthermore, while limiting the regenerative torque upper limit value, the reduction ratio of the coasting regenerative torque is compensated by the engine friction torque to set the gear ratio of the continuously variable transmission CVT when the fluctuation range of the vehicle deceleration becomes the allowable range. Set to "gear ratio". Then, after starting the limitation of the regenerative torque upper limit value, the engagement of the first clutch CL1 is completed until the transmission gear ratio of the continuously variable transmission CVT reaches this "predetermined transmission gear ratio", and the left and right drive wheels of the engine Eng Connect to LT and RT.

  As shown in FIG. 4, this coast time clutch control unit 30 has a coast determination unit 31, a coast regeneration control unit 32, a clutch control unit 33, a regeneration limitation unit 34, and a transmission ratio setting unit 35. doing.

The coast determination unit 31 determines whether or not the FF hybrid vehicle is in a coast travel state based on the accelerator opening degree and the brake depression force. Sensor information from the accelerator opening degree sensor 10 and the brake sensor 21 is input to the coast determination unit 31. Then, when the brake depression force is zero and the accelerator opening degree is the release operation area, the coast determination unit 31 determines that the coast travel state, and outputs a coast determination signal.
In addition, "coast driving" is a state where there is no driving force request from the driver and the vehicle travels with inertia. Further, the "acceleration opening release operation area" is an arbitrary opening area that can be determined that the accelerator pedal is released and, for example, up to 2/8 to 0 (acceleration foot release state) of the accelerator opening. Area

  The coast regeneration control unit 32 receives the coast determination signal from the coast determination unit 31 and sensor information from the accelerator opening degree sensor 10 and the vehicle speed sensor 23. During coasting, the coast regeneration control unit 32 controls the motor generator MG to the regeneration side to generate coast regeneration torque. At this time, regenerative brake control is performed so that the coast regenerative torque becomes the target regenerative torque that is the target value. Here, the target regenerative torque is set according to the vehicle deceleration (necessary deceleration) necessary during coasting. The “necessary deceleration” is determined according to the vehicle speed and the accelerator opening, and FIG. 5 shows the relationship between the required deceleration and the vehicle speed when the accelerator opening is zero. Further, this "necessary deceleration during coasting" is set to a value smaller than the vehicle deceleration that occurs when the maximum value of the regenerative torque (regenerative torque maximum value) that can be generated by motor generator MG is generated. Ru. The “regeneration torque maximum value” is determined by the rating of motor generator MG.

  Furthermore, the coast regeneration control unit 32 sets an upper limit value (regeneration torque upper limit value) of the coast regeneration torque. Here, the regenerative torque upper limit value is set to the regenerative torque maximum value when the limit torque command is not input from the regeneration limiting unit 34. Further, the regenerative torque upper limit value is set to a value obtained by subtracting the limiting torque ΔT from the regenerative torque maximum value when the limiting torque command is input from the regeneration limiting unit 34, and is limited to a value smaller than the regenerative torque maximum value. Ru. That is, the coasting regenerative torque is limited according to the limit torque command when the limit torque command is input from the regeneration limiting unit 34.

  The clutch control unit 33 includes the coast determination signal from the coast determination unit 31, the transmission ratio information from the transmission controller 15, the predetermined transmission ratio information from the transmission ratio setting unit 35, the motor rotational speed sensor 6, and the vehicle speed sensor 23. , And various sensor information from the brake sensor 21 are input. Then, when the coast determination signal is input, the clutch control unit 33 outputs a CL1 release control command to release the first clutch CL1. Further, in the clutch control unit 33, the transmission ratio of the continuously variable transmission CVT reaches a value obtained by subtracting a predetermined margin from the "predetermined transmission ratio" set by the transmission ratio setting unit 35, and the input to the engine Eng When the motor rotation speed Nm, which is the rotation speed, reaches the preset engine rotation speed upper limit value (Ne upper limit value) or less, a CL1 engagement control command for engaging the first clutch CL1 is output. Further, when the brake pedal is depressed while the first clutch CL1 is engaged during coasting, the clutch control unit 33 outputs a first clutch release command when the vehicle speed becomes equal to or less than a predetermined stop threshold. Allow

  The “predetermined margin” is a value that is set according to the engagement time of the first clutch CL1 and is a value that completes the engagement of the first clutch CL1 until the gear ratio reaches the “predetermined gear ratio”. That is, the transmission ratio of the continuously variable transmission CVT is output by outputting the engagement control command to the first clutch CL1 at the timing when the transmission ratio of the continuously variable transmission CVT reaches a value obtained by subtracting the predetermined margin from the "predetermined transmission ratio". The engagement of the first clutch CL1 is completed by the time the predetermined gear ratio is reached.

  The "engine speed upper limit value" is the speed at which the driver does not feel discomfort due to the vibration or sound of the engine Eng when the engine Eng is put into the cranking operation state (the sound vibration performance is acceptable), and the figure It is set according to the map shown in 6 and the vehicle speed. The "stop threshold" is a vehicle speed at which it can be determined that the vehicle has stopped, and is set to, for example, a detection limit value of the vehicle speed sensor 23.

Regeneration limiting unit 34 receives SOC information of battery 9 and temperature information of motor generator MG. The regeneration limiting unit 34 determines whether a regeneration limitation condition is satisfied based on the SOC and the motor temperature. When it is determined that the regeneration limitation condition is satisfied, the regeneration limitation unit 34 calculates the limitation torque ΔT for limiting the regenerative torque upper limit value, and outputs the limitation torque command. The limit torque information is input to the coast regeneration control unit 32 together with the limit torque command.
The "regeneration limitation condition" is a condition set based on, for example, a predetermined value of the SOC or the motor temperature. The “limit torque ΔT” and its rate (slope of change) are set in accordance with the SOC, the motor temperature, the change speed thereof, the amount of change, and the like. The “limit torque ΔT” is a limit amount of the regenerative torque upper limit value with respect to the regenerative torque maximum value.

The gear ratio setting unit 35 defines a “predetermined gear ratio” that defines the timing for engaging the first clutch CL1 and connecting the engine Eng to the left and right driving wheels LT and RT when the coasting regenerative torque is limited during coasting. Set
Here, “predetermined transmission gear ratio” limits the regenerative torque upper limit value, and when performing low return shift control, a reduction torque when the coast regenerative torque is lower than the target regenerative torque due to the limitation of the regenerative torque upper limit value. It is set to the transmission gear ratio at which the fluctuation range of the vehicle deceleration becomes within the allowable range when the minute is compensated by the engine friction torque.
Further, the upper limit value of the "predetermined gear ratio" is set to a value such that the coasting torque and the engine friction torque can be obtained by passing the continuously variable transmission CVT and the drive wheel decelerating torque becomes equal to or less than a predetermined "shock avoidance threshold". Do.

That is, when the regenerative torque upper limit value is limited and falls below the target regenerative torque, the coast regenerative torque is lower than the target regenerative torque. Therefore, the load acting on the vehicle is reduced, and the vehicle deceleration decreases and fluctuates. On the other hand, when the first clutch CL1 is engaged to connect the engine Eng to the left and right drive wheels LT and RT and the engine friction is transmitted to the left and right drive wheels LT and RT, the engine friction becomes a load acting on the vehicle. Therefore, the reduction amount of the coasting regenerative torque with respect to the target regenerative torque can be compensated by the engine friction torque, and the decrease fluctuation of the vehicle deceleration can be suppressed.
On the other hand, at this time, in the continuously variable transmission CVT, the transmission ratio is increasing toward the lowest transmission ratio. That is, the speed change ratio increases as time passes (shifts to Low).
Therefore, the timing for engaging the first clutch CL1 is determined by compensating the decrease in coast regenerative torque with the engine friction torque and determining the gear ratio (predetermined gear ratio) when the fluctuation range of the vehicle deceleration becomes within the allowable range. It is possible to make the fall fluctuation range of the vehicle deceleration within an allowable range.
The “permissible range of fluctuation range of the vehicle deceleration” is set to an arbitrary range in which the driver can tolerate discomfort based on an experiment or the like.

  Further, the “shock avoidance threshold value” is a drive wheel deceleration torque capable of avoiding a shock even if the accelerator pedal operation intervenes during coasting. When the driving wheel deceleration torque is larger than the “shock avoidance threshold value”, when the transmission direction of the driving force is reversed by the intervention of the accelerator depressing operation during coasting, the driving system from the engine Eng to the left and right driving wheels LT, RT A collision occurs in the placed parts, causing a "shock". "Drive wheel deceleration torque" is deceleration torque that acts on left and right drive wheels LT and RT during coasting, and the coast regeneration torque by motor generator MG and the engine friction torque by engine Eng are continuously variable transmission CVT. It is the torque obtained over time.

  The coasting fuel supply control unit 40 prohibits the fuel supply to the engine Eng while the regenerative torque upper limit value is limited during coasting, and does not permit the fuel supply request. That is, when the coast determination signal and the limit torque command are input, the coast time fuel supply limiting unit 40 outputs a fuel cut command for stopping the fuel supply to the engine Eng and sets the fuel cut flag to "1". Set Thus, for example, the fuel supply request is output by the heating ON operation, and even if the fuel cut prohibition flag is set to "1", the fuel supply to the engine Eng is not permitted and the fuel supply request is ignored and the fuel cut state Maintain.

[Coast time clutch control processing configuration]
FIG. 7 is a flowchart showing a flow of a coasting clutch control process executed by the coasting clutch control unit of the first embodiment. Hereinafter, based on FIG. 7, the coast time clutch control processing configuration of the first embodiment will be described. In the coasting clutch control process, the process is repeatedly performed in a cycle set in advance while the FF hybrid vehicle is traveling (while the vehicle speed exceeds the predetermined threshold).

In step S1, the coast determination unit 31 determines whether coasting is in progress. In the case of YES (coast driving), the process proceeds to step S2, and in the case of NO (non-coast driving), step S1 is repeated.
Here, whether or not coasting is being performed is determined based on the accelerator opening degree and the brake depression force, and coasting is being performed when the accelerator opening degree is a predetermined release operation area and the brake depression force is zero. It is judged.

  In step S2, following the determination that coasting is in progress in step S1, the clutch control unit 33 outputs a CL1 release command for releasing the first clutch CL1, and the process proceeds to step S3. As a result, the engine Eng is disconnected from the driveline and transits to the "EV mode".

In step S3, following the output of the CL1 release command in step S2, the coast regeneration control unit 32 sets a target regeneration torque that is a target value of coast regeneration torque generated by the motor generator MG, and proceeds to step S4.
Here, the target regenerative torque is set in accordance with the necessary vehicle deceleration determined based on the accelerator opening and the vehicle speed.

  In step S4, following the setting of the target regenerative torque in step S3, regenerative brake control is performed so that the coast regenerative torque matches the target regenerative torque set in step S3, and the process proceeds to step S5.

In step S5, following the implementation of the regenerative brake control in step S4, the regeneration limiting unit 34 determines whether a predetermined regeneration limitation condition is satisfied. If YES (condition satisfied), the process proceeds to step S6. If NO (condition not satisfied), the process returns to step S3.
Here, whether or not the regeneration limitation condition is satisfied is determined based on the SOC information of battery 9 and the temperature information of motor generator MG.

In step S6, following the determination that the regeneration limitation condition is satisfied in step S5, the regeneration limitation unit 34 limits the upper limit value (regeneration torque upper limit value) of the coast regeneration torque by the limitation torque, and proceeds to step S7.
Here, the limit torque is set in accordance with the SOC, the motor temperature, the changing speed thereof, the amount of change, and the like. Also, in order to limit the regenerative torque upper limit value, a value obtained by subtracting the limit torque from the regenerative torque maximum value is set as a new regenerative torque upper limit value.

In step S7, following the limitation of the regenerative torque upper limit value in step S6, the transmission controller 15 executes low return transmission control to return the transmission ratio of the continuously variable transmission CVT from the highest transmission ratio to the lowest transmission ratio. Determine if it is. In the case of YES (during low return shift), the process proceeds to step S8, and in the case of NO (during constant gear ratio control), the process returns to step S6.
Here, the determination of the low return shift is made based on the vehicle speed and the gear ratio set based on the coast shift line shown in FIG.

In step S8, following the determination of low return shift in step S7, the clutch control unit 33 determines that the actual gear ratio of the continuously variable transmission CVT is equal to or greater than a predetermined gear ratio minus a predetermined margin. Determine if it is or not. If YES (gear ratio ≧ predetermined gear ratio−margin), the process proceeds to step S9. If NO (gear ratio <predetermined gear ratio−margin), the process returns to step S6.
Here, “predetermined transmission gear ratio” refers to the amount by which the engine torque is reduced when the coasting regenerative torque is reduced due to the limitation of the upper limit value of the regenerative torque when the low return shift control is performed by the gear ratio setting unit 35 By compensating with the above, the transmission gear ratio at which the fluctuation range of the vehicle deceleration falls within the allowable range is set.
The upper limit value of the "predetermined gear ratio" is the drive wheel deceleration torque obtained when the coasting regenerative torque and the engine friction torque pass through the continuously variable transmission CVT is a shock even if the accelerator stepping operation intervenes during coasting Is set to a value that is equal to or less than the shock avoidance threshold value.
Furthermore, the “margin” is set according to the engagement time of the first clutch CL1 so as to complete the engagement of the first clutch CL1 until the transmission gear ratio becomes “predetermined transmission gear ratio”.

In step S9, following the determination of gear ratio 所 定 predetermined gear ratio-margin in step S8, the amount of fluctuation of the vehicle deceleration can be made within the allowable range by compensating for the reduction torque of the coasting regenerative torque with the engine friction torque. The clutch control unit 33 determines whether the motor rotational speed Nm, which is the input rotational speed to the engine Eng, is less than or equal to a preset engine rotational speed upper limit value (Ne upper limit value). In the case of YES (Nm ≦ Ne upper limit value), the process proceeds to step S10, and in the case of NO (Nm> Ne upper limit value), the process proceeds to step S11.
Here, the “engine speed upper limit value” is set according to the map shown in FIG. 6 and the vehicle speed.

  In step S10, following the determination of Nm ≦ Ne upper limit value in step S9, the clutch control unit 33 does not give the driver a sense of discomfort due to the vibration or sound of the engine Eng when the engine Eng is put into the cranking operation state. The CL1 engagement command for engaging the first clutch CL1 is output (as the noise and vibration performance is acceptable), and the process proceeds to step S12. As a result, the engine Eng is connected to the drive train and transits to the "HEV mode". At this time, fuel supply to the engine Eng is prohibited, and the engine Eng is in the cranking operation state.

  In step S11, following the determination of Nm> Ne upper limit value in step S9, the clutch control unit 33 gives the driver a sense of discomfort due to the vibration or sound of the engine Eng when the engine Eng is put into the cranking operation state ( As the noise and vibration performance is not acceptable, a motor rotation number command to make the motor rotation number Nm match the engine rotation number upper limit (Ne upper limit) is output, and the process returns to step S9.

In step S12, following the output of the CL1 engagement command in step S10, the clutch control unit 33 determines whether or not the brake pedal is depressed (turned on). In the case of YES (brake ON), the process proceeds to step S13, and in the case of NO (brake OFF), step S12 is repeated.
Here, the presence or absence of the depression operation of the brake pedal is determined based on the brake depression force information from the brake sensor 21.

  In step S13, following the determination of the brake ON in step S12, the clutch control unit 33 determines whether the vehicle speed is equal to or less than a predetermined stop threshold. If YES (vehicle speed ≦ stop threshold), the process proceeds to step S14. If NO (vehicle speed> stop threshold), the process returns to step S12.

  In step S14, following the determination of vehicle speed ≦ stop threshold in step S13, the clutch control unit 33 outputs a CL1 release permission command for permitting release of the first clutch CL1, assuming that the driver's intent to stop is generated. Go to the end. As a result, when the HEV → EV transition request is generated based on the target driving force and the mode transition map shown in FIG. 2, a CL1 release command for releasing the first clutch CL1 is output, and the mode shifts to the “EV mode”.

[Coast-time fuel supply prohibition processing configuration]
FIG. 8 is a flowchart showing the flow of a coasting fuel supply inhibition process executed by the integrated controller of the first embodiment. Hereinafter, the coasting time fuel supply prohibition process configuration of the first embodiment will be described based on FIG. 8. The coast time fuel supply prohibition process is repeatedly performed while the FF hybrid vehicle is coasting.

In step S20, it is determined whether a predetermined regeneration restriction condition is satisfied. In the case of YES (condition satisfied), the process proceeds to step S21, and in the case of NO (condition not satisfied), the process proceeds to step S22.
Here, whether or not the regeneration limitation condition is satisfied is determined based on the SOC information of battery 9 and the temperature information of motor generator MG.

In step S21, following the determination that the regeneration restriction condition is satisfied in step S20, the fuel cut flag is set to "1", and the process proceeds to step S23.
Here, the "fuel cut flag" is a flag that prohibits the fuel supply to the engine Eng (does not permit the fuel supply).

In step S22, following the determination that the regeneration restriction condition is not established in step S20, the fuel cut flag is set to "zero", and the process proceeds to return.
By setting the fuel cut flag to “zero”, the fuel supply to the engine Eng is permitted (the fuel supply is not prohibited), and the fuel supply is performed to the engine Eng when the fuel supply request occurs.

  In step S23, following the fuel supply flag = 1 in step S21, fuel cut to the engine Eng is performed, and the process proceeds to step S24. As a result, when engine Eng is connected to the drive system, cranking operation state is reached as the motor generator MG rotates.

In step S24, following the fuel cut in step S23, it is determined whether a fuel supply request has occurred. In the case of YES (fuel supply required), the process proceeds to step S25, and in the case of NO (no fuel supply required), the process proceeds to step S26.
Here, the fuel supply request is generated, for example, by the ON operation of the in-vehicle heating.

In step S25, following the determination that there is a fuel supply request in step S24, the fuel cut prohibition flag is set to "1", and the process proceeds to step S27.
Here, the "fuel cut prohibition flag" is a flag for prohibiting the fuel supply cut to the engine Eng (permitting the fuel supply).

In step S26, following the determination of no fuel supply request in step S24, the fuel cut inhibition flag is set to "zero", and the process proceeds to return.
By setting the fuel cut prohibition flag to “zero”, the demand for fuel supply to the engine Eng is withdrawn.

In step S27, following the fuel cut prohibition flag = 1 in step S25, the fuel cut state is maintained and the process proceeds to return.
That is, when the regeneration restriction condition is satisfied in step S20, the state of the fuel cut flag is prioritized over the state of the fuel cut prohibition flag. As a result, the fuel supply request is ignored, fuel is not supplied to the engine Eng, and the engine Eng is maintained in the cranking operation state.

Next, the operation will be described.
The operation of the control method and the control device of the hybrid vehicle of the first embodiment is divided into "deceleration fluctuation suppression operation at the time of regeneration limitation", "fuel cut maintaining operation at the regeneration limitation", and "other characteristic operations" Do.

[Deceleration fluctuation suppression action at regeneration limitation]
FIGS. 9A and 9B are time charts showing various characteristics when the motor regeneration limitation occurs during coasting in the first embodiment. Hereinafter, the deceleration fluctuation suppressing action at the time of regeneration limitation of the first embodiment will be described based on FIGS. 9A and 9B.

The FF hybrid vehicle of Embodiment 1, during traveling, when the accelerator opening is operated to a predetermined release operation region at time t ₁ when the time chart shown in FIGS. 9A and 9B, the brake pedal force at that time Is zero, so in the flowchart shown in FIG. 7, the process proceeds to step S1 → step S2 → step S3 → step S4.

That is, assuming that coasting is being performed, a release command is output to the first clutch CL1, and the first clutch CL1 is released. In FIG 9A, release command of time t ₁ earlier than the first clutch CL1 is output, the first clutch CL1 is in a released state. Further, motor generator MG is controlled to the regeneration side to generate coast regeneration torque, but coast regeneration torque generated at this time outputs the vehicle deceleration according to the required deceleration based on the accelerator opening degree and the vehicle speed. It is controlled to match the "target regenerative torque" set to

  Then, when the coast regenerative torque is generated, this coast regenerative torque becomes a load on the drive system of the FF hybrid vehicle, and the vehicle deceleration corresponding to the required deceleration is generated to apply the braking force to the left and right drive wheels LT, RT. Be done. As a result, the vehicle speed gradually decreases.

At time t ₂ ′, when the vehicle speed reaches the first transmission gear ratio VSPα, low return transmission control for downshifting the transmission gear ratio of the continuously variable transmission CVT toward the lowest transmission gear ratio is started.

At time t ₂ the time, when the motor temperature by performing the regeneration regeneration limitation condition is satisfied such as by increasing, in the flowchart shown in FIG. 7 proceeds to step S5 → step S6. Thereby, the limit torque is calculated, and the upper limit value (regeneration torque upper limit value) of the coast regeneration torque is limited by the limit torque. That is, a value obtained by subtracting the calculated limiting torque from the regenerative torque maximum value that can be generated by motor generator MG is set as a new regenerative torque upper limit value. As a result, the regenerative torque upper limit value is limited to a value smaller than the regenerative torque maximum value.

In the example shown in FIGS. 9A and 9B, at time t ₂ when the absolute value of the target regenerative torque is below the absolute value of the regenerative torque upper limit value. Therefore, even if the regenerative torque upper limit value is limited, the coast regenerative torque can be made to coincide with the target regenerative torque, and the vehicle deceleration can be output according to the required deceleration. That is, no change (decrease) in vehicle deceleration occurs.

Furthermore, since in this time t ₂ when a low return speed change control during the process proceeds to step S7 → step S8.

Then, at time t ₄ time, the gear ratio of the continuously variable transmission CVT reaches a value obtained by subtracting a predetermined margin from the "predetermined speed ratio", the gear ratio ≧ predetermined gear ratio - is determined that the margin. Then, the process proceeds from step S8 to step S9. Meanwhile, in this time t ₄ time, since the motor rotation speed Nm is lower than the engine speed upper limit (Ne upper limit), the process proceeds to step S10.

Also, by proceeding to step S10 at time t ₄ time, engagement command to the first clutch CL1 it is output, the first clutch CL1 is engaged. When the first clutch CL1 is engaged, the engine Eng is connected to the drive system, and engine friction torque can be transmitted to the drive system.
Also in the time t ₄ when the absolute value of the target regenerative torque is below the absolute value of the regenerative torque upper limit value. Therefore, the coast regenerative torque can be made to coincide with the target regenerative torque, the vehicle deceleration can be output according to the required deceleration, and the fluctuation (reduction) of the vehicle deceleration does not occur.

At time t ₅ the time, regenerative torque upper limit value in the middle engagement of the first clutch CL1 is equal to the target regenerative torque, then the absolute value of the target regenerative torque is greater than the absolute value of the regenerative torque upper limit value. As a result, the coasting regenerative torque can not be matched with the target regenerative torque, and the vehicle deceleration can not be output according to the request, resulting in a decrease in the vehicle deceleration.

However, in Example 1, at time t ₆ time immediately after time t ₅ the reduction in the vehicle deceleration began to form, occurrence of clutch torque capacity of the first clutch CL1 starts, the engine Eng is started to rotate. The gear ratio is the first clutch CL1 fully engaged at the point time t ₇ reaches a predetermined gear ratio, engine speed and the motor speed is matched. That is, by the transmission ratio of the continuously variable transmission CVT is first clutch CL1 is fully engaged by the time the time t ₇ reaches a predetermined gear ratio, engine friction torque is transmitted to the drive system, FF hybrid the engine friction torque It can be a load on the driveline of the vehicle. Then, the reduction of the coasting regenerative torque can be compensated by the engine friction torque at an appropriate timing, the vehicle deceleration is compensated, and the reduction range of the vehicle deceleration can be within the allowable range.

  That is, in the first embodiment, when the transmission gear ratio of the continuously variable transmission CVT reaches a value obtained by subtracting a predetermined margin from a predetermined transmission gear ratio, an engagement command for engaging the first clutch CL1 is output. Therefore, it is possible to engage the first clutch CL1 before the transmission ratio of the continuously variable transmission CVT reaches the predetermined transmission ratio and the reduction width of the vehicle deceleration exceeds the allowable range. Thus, the engine Eng can be connected to the left and right driving wheels LT and RT at appropriate timing, and when the torque reduction of the coasting regenerative torque due to the limitation of the regenerative torque upper limit is compensated by the engine friction torque, the vehicle The fluctuation range of the deceleration can be made into an acceptable range.

Note that, for example, the timing of the regeneration torque upper limit value is equal to the target regenerative torque (time t ₅ point), i.e., the first clutch from the detection that it is now able to match the coast regenerative torque to the target regenerative torque CL1 in case of outputting the engagement command to enter into the first clutch CL1 is certainly slower than the timing example 1 to complete engagement (time t ₇ time point). Therefore, as shown by a two-dot chain line in FIG. 9B, the timing at which the coast regeneration torque is compensated by the engine friction torque is later than in the case of the first embodiment, and the reduction width of the vehicle deceleration exceeds the allowable range. In particular, during coasting, the driver's pedal operation is hardly performed, and the driver is more likely to feel fluctuation in deceleration. Therefore, the driver may feel discomfort.

In contrast, in Example 1, from the start of the limits of the upper limit of the coast regenerative torque at time t ₂ when, at time t ₇ when the up gear ratio of the continuously variable transmission CVT reaches a predetermined gear ratio, The first clutch CL1 is engaged. That is, the compensation of the coast regeneration torque by the engine friction torque is not in time, and the engagement of the first clutch CL1 is completed before the reduction width of the vehicle deceleration exceeds the allowable range, and the engine Eng is set to the left and right driving wheels LT and RT. It can be connected.

  Therefore, even if the coasting regenerative torque is limited and it becomes impossible to match the coasting regenerative torque to the target regenerative torque, the engine friction torque is used as the load of the drive system while the reduction width of the vehicle deceleration falls within the allowable range. be able to. As a result, when coast regeneration torque is limited during coasting, the vehicle deceleration is compensated at appropriate timing by the engine friction torque, thereby suppressing a significant decrease in the vehicle deceleration and preventing the driver's discomfort from occurring. Can.

[Fuel cut maintenance action at regeneration limit]
In the FF hybrid vehicle of the first embodiment, during coasting, step S20 is determined in the flowchart shown in FIG. 8 during the coasting, and the regeneration limit condition is not satisfied (the upper limit of the coast regeneration torque (regeneration torque upper limit) is limited). If not, the process proceeds from step S20 to step S22. Thus, the fuel cut flag is not set to "zero" and the fuel cut is not prohibited. Therefore, when a fuel supply request occurs, fuel supply to the engine Eng is appropriately performed.

On the other hand, as in the example shown in FIGS. 9A and 9B, at time t ₂ time, the regenerative limiting condition regenerative torque upper limit value is limited satisfied, in the flowchart shown in FIG. 8, step S20 → step S21 → The process proceeds to step S23.
Thus, as is in the regeneration limits, together with the time t the fuel cut flag ₂ time is set to "1" fuel supply is prohibited, the fuel cut to the engine Eng is executed. In FIG. 9B, the time t ₂ before the fuel cut is implemented, and the fuel supply state is in a "cut".

Then, at time t ₃ time, the fuel supply request occurs by being turned ON in the vehicle heating, the flow proceeds to step S24 → step S25 → step S27. As a result, the fuel cut prohibition flag is set to "1". However, since the setting of the fuel-cut flag than the fuel cut prohibition flag is prioritized, although the fuel cut prohibition flag at time t ₃ time is set to "1", fuel cut because the fuel supply is prohibited Continued to run, the fuel supply state remains "cut".

  As described above, in the first embodiment, when the coasting regeneration torque is limited, even if the fuel supply request to the engine Eng is generated, the fuel supply request is ignored, and the engine Eng maintains the cranking operation state. .

As a result, it is possible to prevent the engine friction torque from being suddenly reduced due to the fuel supply.
It is possible to prevent the driver's discomfort from being generated by suppressing the rapid decrease of the vehicle deceleration.

In the example shown in FIG. 9B, if the in-vehicle heating is turned off at time t ₇ ′ after time t ₇ or no fuel supply request is generated, the process proceeds from step S 24 to step S 26 and the fuel cut prohibition flag Is set to "zero". However, at time t ₇ ′, the fuel cut flag is set to “1”, so the fuel supply continues to be prohibited and the fuel cut state is maintained.

At time t ₈ when the brake pedal is depressed, coast traveling is released. As a result, since the regeneration restriction condition is also not satisfied, the process proceeds from step S20 to step S22, and the fuel cut flag is set to "zero". As a result, fuel supply becomes possible, and fuel supply to the engine Eng is executed if, for example, a fuel supply request occurs in response to the heating ON operation.

[Other characteristic actions]
In the first embodiment, the upper limit value of the "predetermined gear ratio", which is the reference of the engagement timing of the first clutch CL1, is a shock avoidance that avoids shock even if the drive wheel deceleration torque intervenes in the accelerator operation during coasting. It is set to a value that is less than or equal to the threshold.

  Here, the driving wheel decelerating torque is a torque obtained by the coasting regenerative torque and the engine friction torque passing through the automatic transmission. Further, the magnitude of the drive wheel reduction torque can be calculated by multiplying the total torque of the coast regeneration torque and the engine friction torque by the transmission ratio of the continuously variable transmission CVT. Therefore, the drive wheel deceleration torque increases as the gear ratio increases.

  On the other hand, with respect to each component of the continuously variable transmission CVT, the final gear mechanism and the like, dimensional tolerances for securing functions, assemblability, and securing manufacturability are set in the axial direction and in the radial direction. Therefore, when the accelerator is depressed during coasting and the drive torque (acceleration torque) acts on the left and right drive wheels LT and RT, the direction of the thrust force applied between the parts changes, resulting in a movement to narrow the gap between the parts. Collision of the two parts occurs. And, a hit sound is generated by this collision, and this becomes a "shock". However, the smaller the thrust force applied between the parts, the smaller this shock. The magnitude of the thrust force depends on the magnitude of the drive wheel decelerating torque.

  Therefore, by defining the upper limit value of the "predetermined gear ratio" to a value that is equal to or less than the "shock avoidance threshold value", the first clutch CL1 is engaged to drive the engine friction torque to the left and right drive wheels LT and RT. It is possible to suppress an increase in the wheel deceleration torque and to suppress the occurrence of a shock even when an accelerator depression operation is performed during coasting.

In the first embodiment, as described above, when the motor rotational speed Nm becomes equal to or lower than the engine rotational speed upper limit value (Ne upper limit value), the engagement command of the first clutch CL1 is output. Therefore, the first clutch CL1 is fully engaged, the engine Eng is left drive wheels LT, the time t ₇ when connected to RT, the engine speed Ne is equal to or less than the engine rotational speed upper limit value (Ne upper limit).

  That is, when the motor rotational speed Nm, which is the input rotational speed to the engine Eng, is less than or equal to a predetermined upper limit rotational speed (the upper limit engine speed Ne upper limit), the engagement command is output to the first clutch CL1, and the engine Eng is It is connected to drive wheels LT and RT.

  As a result, when the engine Eng is in the cranking operation state, it is suppressed that the engine rotational speed becomes unnecessarily high, and it is prevented that the vibration and the sound generated with the rotation of the engine Eng give the driver a sense of discomfort it can. That is, it is possible to prevent the deterioration of the sound vibration performance at the time of compensating for the vehicle deceleration by the engine friction torque.

Further, in the embodiment 1, at time t ₈ point shown in FIGS. 9A and 9B, the brake pedal force is generated, when the brake pedal is determined to depressing operation is performed, step S11 → step in the flowchart shown in FIG. 7 Go to S12. Then, at time t _9, when the vehicle speed reaches a stop threshold value, the release of the first clutch CL1 is permitted proceeds to step S13.
In Example 1 shown in FIGS. 9A and 9B, at the timing when the release is permitted in the first clutch CL1 (time t ₁₀ time), the first clutch release command is outputted.

  Here, when the brake pedal is depressed and the vehicle speed becomes equal to or less than the stop threshold value, it indicates that the driver has a intention to stop. On the other hand, when the vehicle is stopped by the driver's will, there is a demand to stop the rotation of the engine Eng and to alleviate the uncomfortable feeling that the engine noise is generated.

  On the other hand, in the first embodiment, when the brake pedal is depressed and the vehicle speed becomes equal to or less than the stop threshold, and it is determined that the driver intends to stop, the release of the first clutch CL1 is permitted. This makes it possible to separate the engine Eng from the drive system when the vehicle stops at the driver's intention and to set the "EV mode", thereby alleviating the discomfort of the generation of the engine noise when the vehicle is stopped.

Next, the effects will be described.
In the control method and control device for a hybrid vehicle of the first embodiment, the following effects can be obtained.

(1) Engine Eng, motor generator MG, automatic transmission (continuously variable transmission CVT) disposed between the engine Eng and the driving wheels LT, RT, the engine Eng and the automatic transmission And an engine clutch (first clutch CL1) disposed between the step-speed transmission CVT), and the engine clutch (first clutch CL1) is engaged to engage the automatic transmission (stepless transmission CVT) In the control method of a hybrid vehicle, the engine Eng is connected to the drive wheels LT and RT, and the engine clutch (first clutch CL1) is released to disconnect the engine Eng from the drive wheels LT and RT.
During coasting by accelerator release operation, the engine clutch (first clutch CL1) is released to disconnect the engine Eng from the drive wheels LT and RT, and the coast regeneration torque generated by the motor generator MG is used as a target regeneration torque. ,
During low return transmission control of the automatic transmission during coasting, the motor generator MG can generate an upper limit value (regeneration torque upper limit value) of the coast regenerative torque when a predetermined regeneration limitation condition is satisfied. Restrict to a value smaller than the maximum regenerative torque (maximum regenerative torque),
The automatic transmission when the fluctuation range of the vehicle deceleration becomes within the allowable range by compensating the reduction amount of the coasting regenerative torque by the limitation of the coasting regenerative torque upper limit value (regeneration torque upper limit value) with the engine friction torque Set the gear ratio of (CVT) to a predetermined gear ratio,
After the engine clutch (first clutch CL1) starts to limit the upper limit value (regeneration torque upper limit value) of the coast regenerative torque, the gear ratio of the automatic transmission (continuously variable transmission CVT) becomes the predetermined shift It was set up to be concluded before the ratio.
As a result, during coasting, it is possible to prevent a significant reduction of the vehicle deceleration when the coasting regenerative torque is limited, and to prevent the driver from feeling uncomfortable.

(2) The upper limit value of the predetermined gear ratio, the coasting regenerative torque and the drive wheel deceleration torque obtained by the engine friction torque passing through the automatic transmission (continuously variable transmission CVT) during the coasting Even if the accelerator depression operation intervenes, it is set as the value which becomes below the shock avoidance threshold which avoids a shock.
As a result, it is possible to suppress an increase in the driving wheel deceleration torque, and to suppress the occurrence of a shock even when an accelerator depression operation is performed during coasting.

(3) When the upper limit value (regeneration torque upper limit value) of the coasting regenerative torque is limited, the fuel supply to the engine Eng is prohibited and the fuel supply request is not permitted.
As a result, in addition to the effect of (1) or (2), the fuel cut can be maintained, and the driver's discomfort due to the rapid decrease in engine friction torque can be prevented.

(4) When the engine Eng is connected to the drive system, the input rotation speed (motor rotation speed Nm) to the engine Eng is set to a predetermined upper limit rotation speed (engine rotation speed upper limit) or less.
Thereby, in addition to the effect of any one of (1) to (3), when the engine Eng is connected to the drive system, unnecessary increase in engine rotational speed is suppressed, and vibration or sound at the time of engine connection is caused Uncomfortable feeling can be prevented.

(5) When the driver's intention to stop is detected while the engine Eng is connected to the drive system, the engine Eng is permitted to be disconnected from the drive system.
Thereby, in addition to the effect in any one of (1) to (4), it is possible to alleviate the sense of discomfort that the engine sound is generated when the driver stops the vehicle.

(6) The engine Eng, the motor generator MG, the automatic transmission (continuously variable transmission CVT) disposed between the engine Eng and the driving wheels LT, RT, the engine Eng and the automatic transmission A control device (integrated controller 14) of a hybrid vehicle including an engine clutch (first clutch CL1) disposed between the step-speed transmission CVT) and
A clutch control unit 33 for releasing the engine clutch (first clutch CL1) and disconnecting the engine Eng from the drive wheels LT and RT when coasting by accelerator release operation;
A coast regeneration control unit 32 configured to control a coast regeneration torque generated by the motor generator MG to a target regeneration torque at the time of coasting traveling;
A shift control unit (transmission controller 15) that performs a low return shift control that returns the gear ratio of the automatic transmission (continuously variable transmission CVT) to the lowest gear ratio during coasting traveling;
The upper limit value (the regenerative torque upper limit value) of the coast regenerative torque is set to the maximum value of the regenerative torque that can be generated by the motor generator MG when the predetermined regenerative restriction condition is satisfied during the low return shift control. Value limited to a value smaller than
The automatic transmission when the fluctuation range of the vehicle deceleration becomes within the allowable range by compensating the reduction amount of the coasting regenerative torque with the engine friction torque during the limitation of the upper limit value (the regenerative torque upper limit) of the coasting regenerative torque A transmission ratio setting unit 35 for setting the transmission ratio of (the continuously variable transmission CVT) to a predetermined transmission ratio;
The clutch control unit 33 starts limiting the engine clutch (first clutch CL1) to the upper limit value (regeneration torque limit value) of the coast regenerative torque, and then the automatic transmission (continuously variable transmission CVT) The transmission is engaged until the transmission gear ratio reaches the predetermined transmission gear ratio.
As a result, during coasting, it is possible to prevent a significant reduction of the vehicle deceleration when the coasting regenerative torque is limited, and to prevent the driver from feeling uncomfortable.

  As mentioned above, although the control method and control device of the hybrid vehicle of this indication were explained based on Example 1, about a concrete composition, it is not restricted to this example, It is in each claim of a claim. Modifications and additions to the design are permitted without departing from the scope of the invention.

  In the first embodiment, the speed ratio reaches a value obtained by subtracting the margin from the predetermined speed ratio, and the motor speed Nm is the upper limit value of the engine speed (Ne upper limit value) before it is determined that speed ratio 比 predetermined speed ratio−margin. An example is shown in which the first clutch engagement command is output at a timing determined to be lower than the above and that the gear ratio ≧ the predetermined gear ratio−the margin. However, for example, when the relationship of Nm> Ne upper limit value holds at the timing when it is determined that gear ratio ≧ predetermined gear ratio−margin, the process proceeds from step S9 to step S11 in the flowchart shown in FIG. That is, motor rotation number control is performed to make the motor rotation number Nm equal to the engine rotation number upper limit value (Ne upper limit value). Then, when the relationship of Nm ≦ Ne upper limit value is established, the engagement command may be output to the first clutch CL1.

  Further, the timing at which the engine Eng is connected to the drive system may be such that the first clutch CL1 is engaged until the transmission gear ratio of the continuously variable transmission CVT becomes a predetermined transmission gear ratio after restriction of the regenerative torque upper limit is started. . Therefore, for example, the engine Eng may be connected to the drive system immediately after the limitation of the regenerative torque upper limit value is started.

  Further, in the first embodiment, although the example in which the upper limit value of the coasting regenerative torque is limited by the predetermined constant limiting rate after the limitation start of the regenerative torque upper limit value is shown, the present invention is not limited thereto. The limit rate of the regenerative torque upper limit value is arbitrarily set in accordance with the motor temperature, the battery temperature, the change speed such as SOC, the change amount, the size of the target regenerative torque, and the like. That is, after the start of limitation of the regenerative torque upper limit value, a limit rate may be used such that the regenerative torque upper limit value is sharply limited and then gently limited.

  Moreover, although the example which makes "release operation area | region of accelerator opening degree" the area | region to 2/8 to zero (accelerator foot release state), for example of accelerator opening was shown in Example 1, it does not restrict to this. When the accelerator operation amount is zero (accelerator foot release state), it may be determined as “release operation area of accelerator opening degree” and coast driving is to be performed.

  And although the control method of the hybrid vehicle in Example 1 showed the example applied to the FF hybrid vehicle provided with the parallel hybrid drive system called 1 motor 2 clutch, it is not restricted to this. The control method of a hybrid vehicle according to the present disclosure may be a hybrid vehicle capable of connecting / disconnecting the engine Eng to / from the drive system, and controlling the motor generator MG to the regeneration side during coasting to generate coast regeneration torque. Can be applied.

Furthermore, although the example which applies the continuously variable transmission CVT which can change a gear ratio steplessly as an automatic transmission was shown in Example 1, it does not restrict to this. The present invention can be applied to a stepped transmission whose gear ratio is changed stepwise.
In this case, a predetermined gear (for example, the second gear etc.) is set as the "predetermined gear ratio", and the first clutch CL1 is engaged until the shift to the predetermined gear is completed. The fluctuation range of the vehicle deceleration can be within the allowable range.

Eng engine
MG motor generator
CL1 1st clutch (engine clutch)
CL2 second clutch
CVT continuously variable transmission (automatic transmission)
LT left drive wheel
RT Right Drive Wheel 14 Integrated Controller (Control Device for Hybrid Vehicle)
15 Transmission controller (gear shift control unit)
30 coast time clutch control unit 32 coast regeneration control unit 33 clutch control unit 34 regeneration limit unit 35 transmission ratio setting unit 40 coast time fuel supply control unit

Claims (6)

An engine, a motor generator, an automatic transmission disposed between the engine and the drive wheels, and an engine clutch disposed between the engine and the automatic transmission, the engine clutch being engaged In the control method of a hybrid vehicle, the engine is connected to the drive wheel via the automatic transmission, and the engine clutch is released to disconnect the engine from the drive wheel.
During coasting by accelerator release operation, the engine clutch is released to disconnect the engine from the drive wheels, and the coast regeneration torque generated by the motor generator is used as a target regeneration torque,
During low return shift control of the automatic transmission during coasting, the upper limit value of the coast regenerative torque is higher than the maximum value of the regenerative torque that can be generated by the motor generator when a predetermined regeneration limitation condition is satisfied. Restrict to small values,
The reduction ratio of the coasting regenerative torque due to the limitation of the upper limit value of the coasting regenerative torque is compensated by the engine friction torque by compensating the coasting torque by the engine friction torque. Set to gear ratio,
A control method of a hybrid vehicle, characterized in that the engine clutch is engaged until a gear ratio of the automatic transmission becomes the predetermined gear ratio after the restriction of the upper limit value of the coasting regenerative torque is started. In the control method of a hybrid vehicle described in claim 1,
The upper limit value of the predetermined gear ratio, the coasting regenerative torque and the drive wheel deceleration torque obtained by the engine friction torque passing through the automatic transmission may be shocked even if the accelerator stepping operation intervenes during the coasting A control method of a hybrid vehicle, wherein the value is set to a value equal to or less than a shock avoidance threshold value to be avoided. In the control method of a hybrid vehicle described in claim 1 or claim 2,
A control method of a hybrid vehicle, comprising prohibiting fuel supply to the engine and restricting a fuel supply request while limiting the upper limit value of the coasting regenerative torque. The control method of a hybrid vehicle according to any one of claims 1 to 3.
When the said engine clutch is engaged, the input rotation speed to the said engine shall be below a predetermined | prescribed upper limit rotation speed. The control method of the hybrid vehicle characterized by the above-mentioned. The control method of a hybrid vehicle according to any one of claims 1 to 4.
A control method of a hybrid vehicle, comprising: releasing the engine clutch when detecting a driver's intention to stop the vehicle while the engine clutch is engaged. In a control device of a hybrid vehicle including an engine, a motor generator, an automatic transmission disposed between the engine and a driving wheel, and an engine clutch disposed between the engine and the automatic transmission. ,
A clutch control unit that releases the engine clutch and disconnects the engine from the drive wheels during coasting by an accelerator release operation;
A coast regeneration control unit configured to control a coast regeneration torque generated by the motor generator to a target regeneration torque at the time of coasting traveling;
A shift control unit that performs a low return shift control that returns the gear ratio of the automatic transmission to the lowest gear ratio during coasting traveling;
A regeneration limiting unit that limits the upper limit value of the coast regeneration torque to a value smaller than the maximum value of the regeneration torque that can be generated by the motor generator when a predetermined regeneration limitation condition is satisfied during the low return shift control; ,
While limiting the upper limit value of the coasting regenerative torque, the reduction ratio of the coasting regenerative torque is compensated with the engine friction torque to compensate the reduction of the coasting regenerative torque with the engine friction torque, thereby setting the transmission gear ratio of the automatic transmission when A gear ratio setting unit configured to set the gear ratio;
The hybrid clutch characterized in that the clutch control unit engages the engine clutch from when the restriction of the upper limit value of the coasting regenerative torque is started until the gear ratio of the automatic transmission becomes the predetermined gear ratio. Vehicle control device.