JP2012091697A - Vehicle travel control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To properly control engine start and gear-shifting in a coast state.SOLUTION: A vehicle travel control device includes: an engine and a motor being a drive source; a transmission for transmitting drive force from the drive source to a wheel with different gear ratios; an engine start control means controlling engine start; a gear shift control means controlling the gear-shifting of the transmission; and a start determination means for determining whether an engine start request and a gear shift request of the transmission are generated when an own-vehicle travels using only the motor as the drive source and in the coast state. When the start control means determines that the engine start request and the gear shift request of the transmission are generated when the own-vehicle travels using only the motor as the drive source and in the coast state, the engine start control means inhibits starting the engine until the gear shift control means finishes the shift from the current gear position to a target gear position, and then allows the engine to be started after the completion of the shift.

Description

  The present invention relates to a travel control device for a vehicle including an engine and a motor as drive sources.

  Conventionally, a hybrid vehicle including an engine and a motor as drive sources is known. In the hybrid vehicle described in Patent Document 1, when starting the engine in a coast state (in a coasting state), the clutch is released and the engine is disconnected from the driving wheel during the start, and the braking force shared by the engine is obtained. A mechanical brake is used (see Patent Document 1).

JP 2008-221868 A

However, in the technique described in Patent Document 1, after the clutch is released and the engine is started, the driving force of the engine is transmitted to the drive wheels by re-engaging the clutch. In general, when the clutch is engaged, there is a possibility of fluctuations in driving force, shift shocks, and the like.
On the other hand, when both the engine start and the shift request are generated in the coast state, it is necessary to make these controls compatible so as not to cause a driving force fluctuation, a shift shock, and the like accompanying the engine start.
In other words, the conventional technology has room for improvement in starting the engine and controlling the shift in the coast state.
An object of the present invention is to more appropriately perform engine start-up and shift control in a coast state.

  In order to solve the above-described problems, the vehicle travel control device according to the present invention is configured so that the start determination unit is configured to generate an engine start request when the host vehicle travels using only a motor as a drive source and is in a coast state. It is determined whether or not a shift request for the transmission is generated. When the determination condition is met, the engine start control means prohibits starting of the engine until the shift control means completes the change from the current shift speed to the target shift speed, and starts the engine after the change is completed. Let

According to the present invention, the engine is started in a state where the input / output shaft rotation speed of the transmission is increased by changing the transmission. Therefore, it is not necessary to disconnect the engine from the drive wheels at the start, and the negative drive force can be maintained. Further, since the changeover of the transmission is completed, the rotation state of the input shaft of the transmission can be controlled when the engine is started, so that the occurrence of a shift shock can be suppressed.
Therefore, it is possible to more appropriately perform engine start and shift control in the coast state.

1 is a schematic configuration diagram of a hybrid vehicle to which a vehicle travel control device of the present invention is applied. 1 is a configuration diagram illustrating a power train control system (vehicle travel control device) according to the present embodiment. FIG. It is a figure which shows the general | schematic block diagram which shows the basic flow of the command value in control of the integrated controller. 2 is a functional block diagram functionally illustrating control of an integrated controller 21. FIG. It is a functional block diagram of a target drive torque calculating part. It is a figure which shows the transition relationship of vehicle state mode. It is a functional block diagram of a vehicle state mode determination part. It is a flowchart which shows the engine start determination process which the engine start determination process part 21Ea of the integrated controller 21 performs. 3 is a flowchart showing a shift control process executed by an AT controller 24. It is a flowchart which shows the engine starting control process which the engine starting control part 21F performs. It is a figure which shows the time chart which shows operation | movement of a hybrid vehicle.

Next, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
FIG. 1 is a schematic configuration diagram of a hybrid vehicle to which a vehicle travel control device of the present invention is applied. The hybrid vehicle shown in FIG. 1 is an example of rear wheel drive, but the present invention can also be applied to front wheel drive.
(Configuration of drive system)
First, the configuration of the drive system (power train) will be described.
As shown in FIG. 1, the power train of this embodiment includes a motor 2 and an automatic transmission 3 (AT = transmission T / M) in the middle of a torque transmission path from the engine 1 to the left and right rear wheels (drive wheels). Interpose. A first clutch 4 is interposed between the engine 1 and the motor 2. Further, the second clutch 5 is interposed in the torque transmission path between the motor 2 and the driving wheel (rear wheel). In this example, the second clutch 5 constitutes a part of the automatic transmission 3 (AT = transmission T / M). The automatic transmission 3 is connected to drive wheels 7 (rear wheels) via a propeller shaft, a differential 6 and a drive shaft.

The engine 1 is a gasoline engine or a diesel engine. The engine 1 can control the valve opening degree of the throttle valve and the like based on a control command from an engine controller 22 described later. A flywheel may be provided on the output shaft of the engine 1.
The motor 2 is a synchronous motor in which a permanent magnet is embedded in a rotor and a stator coil is wound around a stator, for example. The motor 2 can be controlled by applying a three-phase alternating current generated by an inverter 8 described later based on a control command from a motor controller 23 described later. The motor 2 can also operate as an electric motor that is driven to rotate by receiving power supplied from a battery 9 described later (this state is referred to as “powering”). Further, when the rotor is rotated by an external force, the motor 2 can function as a generator that generates electromotive force at both ends of the stator coil to charge the battery 9 (this operation state is “regeneration”). Called). The rotor of the motor 2 is connected to the input shaft of the automatic transmission 3 via a damper (not shown).

  The first clutch 4 is a hydraulic single-plate clutch interposed between the engine 1 and the motor 2. The first clutch 4 is engaged or disengaged by the control hydraulic pressure created by the first clutch hydraulic unit so that the target clutch transmission torque is inputted based on a control command from the AT controller 24 described later. . The fastening / opening includes sliding fastening and sliding opening.

The second clutch 5 is a hydraulic multi-plate clutch. The second clutch 5 is engaged or disengaged by the control hydraulic pressure generated by the second clutch hydraulic unit so as to achieve the target clutch transmission torque based on a control command from the AT controller 24 described later. The fastening / opening includes sliding fastening and sliding opening.
For example, the automatic transmission 3 determines a stepped gear ratio such as forward 7-speed reverse 1-speed or forward 6-speed reverse 1-speed according to the vehicle speed or the shift accelerator opening degree input from the integrated controller 21 described later. It is a transmission that switches automatically. Here, the second clutch 5 is not newly added as a dedicated clutch, and some of the frictional engagement elements among the plurality of frictional engagement elements that are engaged at each gear stage of the automatic transmission 3 are diverted. And configure.

Here, in this embodiment, the case where the 2nd clutch 5 is comprised as a part of automatic transmission 3 (AT = transmission T / M) is illustrated, However, It is not limited to this. The second clutch 5 may be arranged between the motor 2 and the automatic transmission 3 or between the automatic transmission 3 and the differential gear DF.
Each wheel is provided with a brake unit (not shown). Each brake unit includes, for example, a disc brake and a drum brake. Each brake unit may be a hydraulic brake device or an electric brake device. Each brake unit applies a braking force to the corresponding wheel in response to a command from the brake controller 25. Note that the brake unit need not be provided on all wheels.

  In FIG. 1, reference numeral 14 denotes an electric sub oil pump, and reference numeral 15 denotes a mechanical oil pump. These oil pumps 14 and 15 generate hydraulic pressure for each clutch. Reference numeral 10 denotes an engine rotation sensor that detects the rotational speed of the engine 1, and reference numeral 11 denotes a motor rotation sensor such as a resolver that detects the rotation of the motor 2. Reference numeral 12 denotes an AT input rotation sensor that detects rotation of the input shaft of the transmission, and reference numeral 13 denotes an AT output rotation sensor that detects rotation of the output shaft of the transmission. Moreover, the code | symbol 27 shows the wheel speed sensor which detects rotation of a wheel. The wheel speed sensor 27 may also be provided on a driven wheel (front wheel) (not shown).

FIG. 2 is a block diagram illustrating the power train control system (vehicle travel control device) shown in FIG.
Reference numeral 33 denotes an accelerator pedal 33 operated by the driver. The accelerator opening APO of the accelerator pedal 33 is detected by the accelerator sensor 20, and the accelerator sensor 20 outputs the detected accelerator opening APO information to the integrated controller 21.
Reference numeral 34 denotes a pedal actuator 34. The pedal actuator 34 is an actuator that applies a pedal reaction force according to a command from the inter-vehicle controller 31 to the accelerator pedal 33.

Reference numeral 32 denotes a radar unit 32 constituting the preceding vehicle detection means. The radar unit 32 detects a preceding vehicle ahead of the vehicle and outputs the detected preceding vehicle information to the inter-vehicle distance controller 31.
Reference numeral 27 denotes a wheel speed sensor. The wheel speed sensor 27 outputs the detected wheel speed information to the brake controller 25. Further, the vehicle speed information obtained from the wheel speed information is output from the brake controller 25 to the integrated controller 21 and the inter-vehicle controller 31.
Reference numeral 35 is a meter for presenting the driving state to the driver. The meter 35 displays auto cruise information and the like.

Reference numeral 29 denotes a brake switch 29. The brake switch 29 detects an operation of a brake pedal (not shown).
Reference numeral 28 denotes a steering switch. The steering switch 28 is an operator for a driver to perform an automatic cruise control start-up of an automatic cruise control, a change instruction of a driving condition (target vehicle speed, etc.), or a shift-up / shift-down instruction by a manual operation. Here, the cruise travel of this embodiment includes both constant speed travel control (constant speed cruise) and inter-vehicle control control (inter-vehicle cruise).

Reference numeral 30 denotes a cruise cancel switch provided on the brake pedal. The cruise cancel switch 30 is an operator for instructing the end of the automatic cruise traveling that is automatic traveling control. The steering switch 28 also has a switch for ending auto cruise. This switch is also referred to as a cruise cancel switch 30.
Reference numeral 18 denotes a voltage sensor for detecting the voltage of the battery 9. Reference numeral 19 denotes a current sensor for detecting the current of the battery 9.

Next, the configuration of the control system of the hybrid vehicle will be described.
As shown in FIG. 2, the hybrid vehicle control system includes an engine controller 22, a motor controller 23, an inverter 8, a battery controller 26, an AT controller 24, a brake controller 25, and an integrated controller 21. Have. Further, the control system of the hybrid vehicle of this embodiment includes an inter-vehicle distance controller 31.
Note that the engine controller 22, the motor controller 23, the AT controller 24, the AT controller 24, the brake controller 25, the inter-vehicle control controller 31, and the integrated controller 21 are CAN communication lines (not compatible) that can exchange information with each other. Connected through the figure.

  The engine controller 22 inputs engine speed information detected by the engine speed sensor 10. The engine controller 22 sends a command for controlling the engine operating point (Ne: engine speed, Te: engine torque) to the throttle valve actuator (not shown), for example, in accordance with the target engine torque from the integrated controller 21. Output. Information about the engine speed Ne is acquired from the integrated controller 21 via the CAN communication line.

The motor controller 23 inputs information detected by the motor rotation sensor 11 that detects the rotor rotation position of the motor 2. Then, the motor controller 23 inverts a command for controlling the motor operating point (Nm: motor generator rotational speed, Tm: motor generator torque) of the motor 2 in accordance with a target motor torque, a rotational speed command or the like from the integrated controller 21. Output to 8.
The battery controller 26 monitors the battery SOC that represents the state of charge of the battery 9. The battery controller 26 supplies battery SOC information to the integrated controller 21 via the CAN communication line as control information of the motor 2 or the like.

  The AT controller 24 inputs wheel information and sensor information from the first and second clutch hydraulic pressure sensors. Then, the AT controller 24 performs the second clutch control in the shift control according to the accelerator opening APO state from the integrated controller 21 and the first and second clutch control commands (target first clutch torque, target second clutch torque). Is output to the second clutch hydraulic unit in the AT hydraulic control valve, and the command for controlling the engagement / release of the first clutch 4 is output to the first clutch hydraulic pressure. Output to a unit (not shown).

Further, the AT controller 24 performs phases in the order of region A (torque control), region B (rotational speed control), region C (rotational speed control), and region D (torque control) in the shift control of the second clutch 5. Transition. Then, the AT controller 24 outputs an area A completion notification to the integrated controller 21 when the area A is completed.
In this embodiment, when a shift request and a start request for the engine 1 occur simultaneously during coasting, the integrated controller 21 delays the start of the engine 1 until completion of the region A by an engine start determination process described later, and the AT controller Priority is given to the shift control by 24.

  The brake controller 25 inputs sensor information from a wheel speed sensor 27 for detecting each wheel speed of the four wheels and a brake stroke sensor. The brake controller 25 calculates a target deceleration based on the stroke amount of the brake pedal, the braking request amount from the inter-vehicle controller 31 and the vehicle speed in a preset control cycle. The brake controller 25 distributes the braking force to the target regenerative braking request torque using the target deceleration as the rotational braking force and the target hydraulic braking force as the mechanical braking force (hydraulic braking force) as the regenerative cooperative brake control. Then, the cooperative regenerative brake request torque is output to the motor controller 23 of the integrated controller 21. The target hydraulic braking force is output to the hydraulic braking force device. For example, the brake controller 25 performs regenerative cooperative brake control when the regenerative braking force is insufficient with respect to the required braking force obtained from the brake stroke BS or the like at the time of brake depression. Then, regenerative cooperative brake control is performed based on the regenerative cooperative control command from the integrated controller 21 so that the shortage is compensated by mechanical braking force (hydraulic braking force or motor 2 braking force).

  Further, the inter-vehicle controller 31 receives information on the steering switch 28 set by the driver, cruise control operation permission state, and other necessary information from the integrated controller 21. When the inter-vehicle controller 31 determines that the inter-vehicle control is to be performed on the preceding vehicle based on the information from the integrated controller 21, the preceding vehicle information (the inter-vehicle distance, the relative speed, etc.) based on the own vehicle speed and the detection of the radar unit 32. Based on the above, a target acceleration and a target deceleration for calculating the target inter-vehicle distance and the target inter-vehicle time with respect to the preceding vehicle are calculated. Then, the inter-vehicle controller 31 outputs the obtained target acceleration to the integrated controller 21 as inter-vehicle cruise request torque (ACC required torque). Further, the inter-vehicle controller 31 outputs the obtained target deceleration to the brake controller 25 as a braking request torque.

  The inter-vehicle distance controller 31 includes a DCA control (Distance Control Assist) unit 31A. The DCA control unit 31A calculates a pedal reaction force command based on accelerator opening APO information received from the integrated controller 21, vehicle speed information based on detection by the wheel speed sensor 27, and information from the radar unit 32. Then, the DCA control unit 31A outputs the calculated reaction force command to the pedal actuator 34 as support information for the driver to keep the distance from the preceding vehicle. The pedal actuator 34 applies a reaction force to the input accelerator pedal 33.

The integrated controller 21 is responsible for managing the energy consumption of the entire vehicle and running the vehicle with the highest efficiency.
The integrated controller 21 includes an engine speed sensor 10 that detects an engine speed Ne, a motor speed sensor 11 that detects a motor speed Nm, an AT input speed sensor 12 that detects a transmission input speed, and a transmission output speed. Information from the AT output rotation sensor 13 is detected. Further, the integrated controller 21 inputs accelerator opening APO information from the accelerator sensor 20 and information on the storage state SOC of the battery 9 from the battery controller 26. Further, the integrated controller 21 outputs information acquired via the CAN communication line.

  Further, the integrated controller 21 performs operation control of the engine 1 in accordance with a control command to the engine controller 22. The integrated controller 21 executes operation control of the motor 2 according to a control command to the motor controller 23. The integrated controller 21 executes engagement / release control of the first clutch 4 according to a control command to the AT controller 24. The integrated controller 21 executes the engagement / release control of the second clutch 5 according to a control command to the AT controller 24. The integrated controller 21 controls engine start during gear shifting in a coast state by a control command to the engine controller 22.

Here, the basic operation mode in the hybrid vehicle of the present embodiment will be described.
If the battery SOC is low while the vehicle is stopped, the engine 1 is started to generate electric power, and the battery 9 is charged. When the battery SOC is in the normal range, the first clutch 4 is engaged and the second clutch 5 is released, and the engine 1 is stopped.
At the time of starting by the engine 1, the motor 2 is rotated according to the accelerator opening APO and the battery SOC state to switch to power running / power generation.

Motor running (EV mode) secures the motor torque and battery output necessary for starting the engine, and shifts to engine running if insufficient. Further, when the vehicle speed exceeds a predetermined vehicle speed set in advance based on a preset map or the like, the motor drive (EV mode) is shifted to the engine drive (HEV mode). In addition, when the engine is running, the motor 2 assists the engine torque delay in order to improve the response when the accelerator is depressed. That is, while the engine is running, there is a mode in which the vehicle runs with only the power of the engine 1 or with both the power of the engine 1 and the motor 2.
At the time of brake-on deceleration, a deceleration force corresponding to the driver's brake operation is obtained by regenerative cooperative brake control.
At the time of shifting during engine traveling or motor traveling, the motor 2 is regenerated / powered for smooth rotation without torque converter in order to adjust the rotational speed associated with shifting during acceleration / deceleration.

When the engine is in the coast state in the EV mode, when an engine start request and a shift request are generated, the integrated controller 21 executes an engine start determination process to switch the shift stage of the automatic transmission 3 to the target shift stage, and the automatic shift After the machine 3 shifts to the inertia phase, the engine 1 is allowed to start.
FIG. 3 illustrates a schematic configuration diagram illustrating a basic flow of command values in the control of the integrated controller 21 of the present embodiment. FIG. 4 is a functional block diagram functionally illustrating the control of the integrated controller 21 of the present embodiment.

Next, a part related to the present invention in the braking / driving control process executed by the integrated controller 21 will be described.
As shown in FIG. 4, the integrated controller 21 includes a required power generation torque calculation unit 21A, a required engine torque calculation unit 21B, a motor output possible torque calculation unit 21C, a target drive torque calculation unit 21D, a vehicle state mode determination unit 21E, an engine start A control unit 21F, an engine stop control unit 21G, a target engine torque calculation unit 21H, a target motor torque calculation unit 21J, and a target clutch torque calculation unit 21K are provided.

The required power generation torque calculator 21A calculates the required power generation torque to be generated by the motor 2 based on vehicle speed information, battery information such as SOC from the battery controller 26, and the like.
The required engine torque calculation unit 21B calculates the required engine torque that should be generated in the engine 1 based on the running state such as the vehicle speed, the required power generation torque calculated by the required power generation torque calculation unit 21A, and the like.
The motor output possible torque calculation unit 21C calculates motor output possible torque that the motor 2 can output based on battery information such as SOC from the battery controller 26, vehicle speed, and the like.

  The target drive torque calculation unit 21D calculates a target drive torque to be targeted. The target drive torque calculator 21D includes a driver request torque calculator and an automatic control request torque calculator. The driver request torque calculation unit calculates the driver request torque that is estimated to be requested by the driver based on the operation amount (accelerator opening APO) of the accelerator pedal 33 operated by the driver. In addition, the automatic control request torque calculation unit is operated by operating a steering switch that is an automatic travel control switch, and is kept in a traveling state of a traveling condition (set vehicle speed) preset by the driver until the operation is terminated by the operation of the cruise cancel switch 30. Calculate the required torque for automatic control for automatic adjustment. Then, the target drive torque calculator 21D calculates the target drive torque based on the driver request torque calculated by the driver request torque calculator and the automatic control request torque calculated by the automatic control request torque calculator.

As shown in FIG. 5, the target drive torque calculation unit 21D of the present embodiment includes a driver request torque calculation unit 21Da, an automatic control request torque calculation unit 21Db, a first target drive torque calculation unit 21Dc, a vehicle speed limiter torque calculation unit 21Dd, The final target drive torque calculation unit 21De is provided.
The driver request torque calculation unit 21Da calculates the driver request torque based on at least the accelerator opening APO information of the accelerator pedal 33 and the vehicle speed. In the example shown in FIG. 3, the driver request torque calculation unit 21Da inputs the accelerator opening APO and the transmission input rotation speed, and calculates the basic driver request torque with reference to the base torque map. Further, the first correction torque is calculated based on the vehicle speed with reference to the creep / coast driving force table. Further, the second correction torque is calculated with reference to the MG assist torque MAP based on the power limit information based on the accelerator opening APO information, the transmission input rotation speed, the SOC, and the like. Then, the driver request torque calculation unit 21Da calculates a final driver request torque based on the calculated basic driver request torque, the first correction torque, and the second correction torque.

  The automatic control request torque calculation unit 21Db outputs the steering switch 28 and the ACC permission signal to the inter-vehicle control controller 31 and inputs the inter-vehicle cruise request torque (ACC required torque) from the inter-vehicle control controller 31. Further, the automatic control request torque calculation unit 21Db calculates a cruise request torque for feedback control to the set vehicle speed based on the set vehicle speed set by the steering ring SW and the current vehicle speed. The automatic control request torque selects either the inter-vehicle cruise request torque (ACC request torque) or the cruise request torque as the automatic control request torque according to the presence or absence of the ACC operation (the inter-vehicle control operation). Here, during the ACC operation, processing is performed so that the inter-vehicle cruise request torque is selected with priority over the cruise request torque.

The first target drive torque calculation unit 21Dc performs a select high of the driver request torque calculated by the driver request torque calculation unit 21Da and the automatic control request torque calculated by the automatic control request torque calculation unit 21Db. One target drive torque is selected and output.
The vehicle speed limiter torque calculating unit 21Dd calculates a vehicle speed limiter torque for setting the vehicle speed to be equal to or lower than the upper limit vehicle speed based on the set vehicle speed set by the steering switch 28 and the current vehicle speed.
The final target drive torque calculation unit 21De performs a select low between the first target drive torque output by the first target drive torque calculation unit 21Dc and the vehicle speed limiter torque calculated by the vehicle speed limiter torque calculation unit 21Dd. That is, the target drive torque is obtained by limiting the first target drive torque with the vehicle speed limiter torque.

  The vehicle state mode determination unit 21E determines a vehicle state mode region map (EV-HEV transition) based on the accelerator opening APO, vehicle speed information (or transmission output speed), motor output possible torque, required engine torque, and target drive torque. A target vehicle state mode (EV mode, HEV mode) as a target is determined with reference to a map). For example, when the torque obtained by adding the cranking torque necessary for starting the engine 1 to the target drive torque for vehicle braking / driving control falls below the torque that the motor 2 can output, the operation mode is changed from the HEV mode to the EV mode. Transition. Further, when there is a required engine torque due to a request such as battery charging, the target vehicle state mode that is a target is set to the HEV mode. If the current vehicle state mode is the EV mode and the target vehicle state mode is the HEV mode, the engine start sequence is processed. Further, when the current vehicle state mode is the HEV mode and the target vehicle state mode is the EV mode, the engine stop sequence is processed.

  Here, as shown in FIG. 6, the vehicle state mode includes an HEV mode, an EV mode, and an engine stop sequence mode and an engine start sequence mode which are modes at the time of transition. The HEV mode is a vehicle state mode in which the vehicle travels with at least the engine 1 as a drive source. The mode of the engine stop sequence is a vehicle state mode at the time of transition when shifting from the HEV mode to the EV mode. The engine start sequence mode is a vehicle state mode at the time of transition from the EV mode to the HEV mode. When the current vehicle state mode and the target vehicle state mode are the same, the previous state mode is maintained. For example, when the current vehicle state mode is the EV mode and the target vehicle state mode is also the EV mode, the vehicle state mode is set to the EV mode. When the current vehicle state mode is the HEV mode and the target vehicle state mode is also the HEV mode, the vehicle state mode is set to the HEV mode. On the other hand, when the current vehicle state mode is the EV mode and the target vehicle state mode is the HEV mode, or when the current vehicle state mode is the HEV mode and the target vehicle state mode is the EV mode, the transition mode of the engine 1 Until the stop or start process is completed, the engine stop sequence mode or the engine start sequence mode is entered.

As shown in FIG. 7, the vehicle state mode determination unit 21E in the present embodiment includes an engine start determination processing unit 21Ea and an engine stop determination processing unit 21Eb.
The engine start determination processing unit 21Ea determines the engine start. In the engine start determination processing unit 21Ea of the present embodiment, the engine start determination is performed in response to an engine start request based on the accelerator opening APO, an engine start request by the system (when the battery SOC decreases, etc.), an engine start request by cruise, and the like. To turn on the engine start request.
Further, when an engine start request is generated in the EV mode, the engine start determination processing unit 21Ea of the present embodiment performs an engine start determination process described later.

The engine stop determination processing unit 21Eb determines whether the engine is stopped. In the engine stop determination processing unit 21Eb of the present embodiment, when any of the following conditions is satisfied, the engine stop request is turned ON. If none of the following conditions are satisfied, the engine stop request is turned OFF.
・ Accelerator opening APO is less than the preset engine stop opening ・ Cruise required torque (target drive torque) is less than the preset engine stop torque However, if there is a stop prohibition request due to a system request, the engine stop request is turned OFF And The stop prohibition request due to the system request is, for example, a case where the SOC is lowered below a preset value, a water temperature is below a preset temperature, a vehicle speed that is equal to or higher than the allowable number of revolutions of the motor 2, and the like.

The engine start control unit 21F operates when the engine start flag is ON, performs a process of starting the engine 1 while the motor is running, and performs a transition process to the HEV mode.
The engine stop control unit 21G is activated when an engine stop command (engine stop flag is ON) is acquired, and from the engine running, the motor 2 is driven to perform a transition process to the EV mode.

  For example, the engine stop control unit 21G is activated upon obtaining an engine stop command (engine stop flag is ON), and first outputs a preset torque command for slidingly engaging the first clutch 4 to the AT controller 24. To do. Synchronously, a command for controlling the rotational speed of the motor 2 is output to the motor controller 23. Thereby, while reducing the torque from the engine 1 by the first clutch 4, the motor torque is increased to obtain the target drive torque. When the target motor torque becomes the target drive torque, a target first clutch 4 torque command for setting the first clutch 4 to target clutch transmission torque = 0 is output to the AT controller 24. Thereafter, a target engine torque of zero is output to the engine controller 22. As a result, the engine is fuel cut (F / C), and the engine is idling.

  The target engine torque calculation unit 21H calculates the target engine torque based on the target vehicle state mode determined by the vehicle state mode determination unit 21E, travel state information such as vehicle speed, target drive torque, and requested engine torque required for power generation. calculate. Note that when the target vehicle state mode is the EV mode, the engine torque is unnecessary, so the target engine torque is zero or a negative value. When the preset F / C condition is satisfied, fuel cut (F / C) is instructed to the engine, and the engine is idling.

  The target motor torque calculation unit 21J calculates the target motor torque based on the target vehicle state mode determined by the vehicle state mode determination unit 21E, travel state information such as vehicle speed, target drive torque, and required power generation torque. For example, a value obtained by subtracting a torque value obtained by performing delay correction on the target engine torque from the target drive torque is set as the target motor torque. When the regenerative brake request torque (<0) is input from another control unit, a value obtained by adding the regenerative brake request torque to the target motor torque is set as the final target motor torque.

The target clutch torque calculation unit 21K calculates target clutch torques of the first clutch 4 and the second clutch 5 based on the target vehicle state mode determined by the vehicle state mode determination unit 21E and the torque generated by the engine 1 and the motor 2. . In the EV mode state, the first clutch 4 is normally output to the AT controller 24 by outputting a release command for the first clutch 4 and outputting an engagement command for the second clutch 5 to the AT controller 24. The second clutch 5 is brought into the engaged state while being in the released state. Further, in the HEV mode state, the first clutch 4 is normally output to the AT controller 24 by outputting the engagement command of the first clutch 4 and outputting the engagement command of the second clutch 5 to the AT controller 24. The second clutch 5 is brought into an engaged state while being brought into an engaged state. In addition, in the case of engine start or stop processing, the clutch torque that results in the above-described engagement / release state is calculated.
Note that the VAPO calculation 21L in FIG. 3 calculates the corresponding estimated accelerator opening from the cruise request torque, and outputs the calculated estimated accelerator opening to the AT controller 24 as the shift accelerator opening.

(Engine start determination process)
The processing of the engine start determination processing unit 21Ea will be described with reference to the flowchart of FIG.
FIG. 8 is a flowchart showing an engine start determination process executed by the engine start determination processing unit 21Ea of the integrated controller 21. The engine start determination process is a process executed when a start request for the engine 1 is generated in the EV mode.
When the engine start determination process is started, the engine start determination processing unit 21Ea determines whether or not the current running state is a coast state (step S101). Whether or not it is in a coast state can be determined by whether or not the accelerator opening APO is zero.

If it is determined in step S101 that the vehicle is not in the coast state, the engine start determination processing unit 21Ea ends the engine start determination processing. In this case, the routine proceeds to an engine start sequence (basic engine start sequence) corresponding to the vehicle speed, required torque, and the like.
On the other hand, when it is determined in step S101 that the vehicle is in the coast state, the engine start determination processing unit 21Ea determines whether or not there is a shift request for the automatic transmission 3 (step S102), and determines that there is no shift request. If so, the engine start determination process is terminated. Also in this case, the routine proceeds to an engine start sequence (basic engine start sequence) corresponding to the vehicle speed, the required torque, and the like.
On the other hand, when it is determined in step S102 that there is a shift request for the automatic transmission 3, the engine start determination processing unit 21Ea outputs a shift control command to the AT controller 24 (step S103).

Next, the engine start determination processing unit 21Ea sets a start prohibition flag indicating start prohibition of the engine 1 (start prohibition flag = ON) (step S104), sets the start target rotation speed of the engine 1 and performs engine start control. It outputs to the part 21F and the motor controller 23 (step S105). The starting target rotational speed is set on the (+) side of the rotational speed corresponding to the current gear position and on the (−) side of the rotational speed corresponding to the target gear speed.
For example, the starting target rotational speed can be determined as (target gear stage gear ratio × output rotational speed of second clutch 5 × set coefficient). However, the coefficient at this time is determined so as to be the (−) side rotational speed with respect to the target shift stage.
Note that the target rotational speed may be set to a target rotational speed at the time of coast down shift without engine start.

Next, the engine start determination processing unit 21Ea determines whether or not the change of the second clutch 5 (automatic transmission 3) has been completed (step S106). Whether or not the second clutch has been changed is determined by whether or not a region A completion notification is received from the AT controller 24.
If it is determined in step S106 that the second clutch 5 has not been changed, the engine start determination processing unit 21Ea repeats the determination in step S106, and if it is determined that the second clutch 5 has been changed, the engine start determination processing unit 21Ea 1 start prohibition flag is canceled (start prohibition flag = OFF) (step S107).

Next, the engine start determination processing unit 21Ea sets an engine start flag indicating that the engine start sequence is being performed (engine start flag = ON) (step S108), and starts the engine start sequence (see FIG. 10) ( Step S109).
Next, the engine start determination processing unit 21Ea determines whether or not the engine speed has reached the speed change target speed corresponding to the speed target shift speed (step S110), and the engine speed becomes the speed change target speed. If it is determined that the value has not been reached, the determination in step S110 is repeated.
On the other hand, when it is determined that the engine speed has reached the speed change target speed, the engine start determination processing unit 21Ea cancels the engine start flag (engine start flag = OFF) (step S111), and ends the engine start determination process. To do.

(Shift control process)
Next, the shift control process executed by the AT controller 24 will be described.
FIG. 9 is a flowchart showing a shift control process executed by the AT controller 24.
In step S103 of the engine start determination process, the AT controller 24 starts the shift control process in response to the engine start determination processing unit 21Ea inputting a shift control command.
When the shift control process is started, the AT controller 24 starts the torque control of the region A in the shift control phase (step S201).

Next, the AT controller 24 determines whether or not the second clutch 5 (automatic transmission 3) has been changed (step S202), and determines that the second clutch 5 has not been changed. The determination in step S202 is repeated.
On the other hand, if it is determined in step S202 that the switching of the second clutch 5 has been completed, the AT controller 24 outputs a region A completion notification indicating that the region A phase has been completed to the integrated controller 21 (step S203). .

Next, the AT controller 24 shifts from the torque control in the region A to the rotational speed control (regions B and C) in the phase of the shift control (step 204).
Then, the AT controller 24 determines whether or not the motor rotation speed Nm is the start target rotation speed of the engine 1 (step S205).
If it is determined in step S205 that the motor rotational speed Nm is not equal to the starting target rotational speed of the engine 1, the AT controller 24 performs control to change the rotational speed by the motor 2 at the set change rate (step S206). . The control in step S206 is executed by feedback control. When the feedback control is completed, the process proceeds to determination in step S205.

If it is determined in step S205 that the motor speed Nm is equal to the target start speed of the engine 1, the AT controller 24 determines that the speed of the engine 1 has reached the start target speed from the engine start control unit 21F. It is determined whether or not a start target rotational speed attainment notification indicating that there is an input (step S207).
If it is determined in step S207 that the start target rotation speed arrival notification has not been input, the AT controller 24 repeats the determination in step S207.
On the other hand, if it is determined in step S207 that the start target rotation speed attainment notification has been input, the AT controller 24 increases the engagement force of the first clutch 4 and changes the rotation speed of the motor 2 at the set rate of change ( Step S208). The control in step S208 is executed by feedback control.

Next, the AT controller 24 determines whether or not the rotational speed of the motor 2 is the shift target rotational speed (step S209).
If it is determined in step S209 that the rotation speed of the motor 2 is not the shift target rotation speed, the AT controller 24 repeats the determination in step S209.
On the other hand, if it is determined in step S209 that the rotational speed of the motor 2 is the shift target rotational speed, the AT controller 24 determines that the rotational speed of the engine 1 has reached the shift target rotational speed from the engine start control unit 21F. It is determined whether or not a shift target rotation speed arrival notification indicating that there is an input (step S210).

If it is determined in step S210 that the shift target rotation speed arrival notification has not been input, the AT controller 24 repeats the determination in step S210.
On the other hand, if it is determined in step S210 that the shift target rotation speed arrival notification has been input, the AT controller 24 shifts from the rotation speed control in the regions B and C to the torque control in the region D in the phase of the shift control ( Step S211). In a region D, the fastening force between the input side fastening element and the output side fastening element of the second clutch 5 is increased at a rate of change that does not cause a shift shock, and is finally in a completely fastened state.
After step S211, the AT controller 24 ends the shift control process.

(Engine start control process)
Next, engine start control processing executed by the engine start control unit 21F will be described.
FIG. 10 is a flowchart showing an engine start control process executed by the engine start control unit 21F.
The engine start control unit 21F starts the engine start control process in response to the engine start determination processing unit 21Ea starting the engine start sequence in step S109 of the engine start determination process.
When the engine start control process is started, the engine start control unit 21F sets a start target rotation speed at the time of engine start (step S301). The starting target rotation speed is input from the integrated controller 21.

Next, the engine start control unit 21F starts the engine 1 by outputting a start command for the engine 1 to the engine controller 22 (step S302). At this time, as determined in step S101 of the engine start determination process, since the current running state is the coast state, the engine 1 is started in a fuel cut state.
Next, the engine start control unit 21F determines whether or not the engine speed Ne is the start target speed (step S303).

If it is determined in step S303 that the engine speed Ne is not equal to the target start speed, the engine start control unit 21F repeats the determination in step S303.
On the other hand, when it is determined in step S303 that the engine speed Ne is equal to the target start speed, the engine start control unit 21F outputs a start target speed reach notification to the AT controller 24 (step S304). .
Next, the engine start control unit 21F determines whether or not the engine rotational speed Ne is the shift target rotational speed (step S305).
If it is determined in step S305 that the engine speed Ne is not equal to the shift target speed, the engine start control unit 21F repeats the determination in step S305.

On the other hand, when it is determined in step S305 that the engine speed Ne is the shift target rotation speed, the engine start control unit 21F outputs a shift target rotation speed arrival notification to the AT controller 24 (step S306).
Next, the engine start control unit 21F shifts to a state (normal traveling state) in which engine control based on the required engine torque and the target rotational speed is performed (step S307).
Then, the engine start control unit 21F ends the engine start control process.

(Operation)
Next, the operation of the hybrid vehicle will be described with reference to the time chart of FIG.
FIG. 11 is a diagram showing a time chart showing the operation of the hybrid vehicle in the present invention.
FIG. 11 shows a time chart in the coast state when an engine start request is generated in the EV mode (when the engine start determination process in FIG. 8 is activated).

  11A shows the flow of the operation signal of the accelerator opening APO and the shift down switch DWSW, and FIG. 11B shows the output signal of the AT controller 24 (the target shift stage NXTGP_MAP based on the shift line, the target shift stage). The flow of the shift start to SFTGP and the current shift stage CURGP) is shown. FIG. 11C shows the flow of the coast driving force (target value), and FIG. 11D shows the engine control signals (engine speed control flags SIP: 4, SIP: 6 during shifting) The flow of an engine start flag ENGSTART, an engine start completion flag ENGCNKOK, and a start prohibition flag) is shown. Note that SIP: 4 is an engine speed control flag at the time of a normal shift without engine start, and SIP: 6 is an engine speed control flag at the time of a shift with engine start.

  FIG. 11E shows the flow of signals for engine speed control (engine speed ENGREV, motor speed Motor_REV, start target speed Target_REV). FIG. 11 (f) shows the flow of the actual hydraulic pressure Apply_PRS of the engagement side engagement element (shift stage after the shift), and FIG. 11 (g) shows the actual hydraulic pressure Release_PRS of the release side engagement element (transmission stage before the shift). The flow is shown. FIG. 11 (h) shows the flow of the engagement pressure CL2_PRS of the second clutch 5 and the stroke position CL1_STRK of the hydraulic actuator of the first clutch 4. The stroke position of the hydraulic actuator of the first clutch 4 that is a hydraulic single-plate clutch corresponds to the engagement pressure of the first clutch 4 (the maximum level is released and the minimum level is fully engaged). FIG. 11 (i) shows the flow of driving torque of the engine 1 and the motor 2, and FIG. 11 (j) shows the flow of driving force of the hybrid vehicle.

  When a shift request is generated by operating the downshift switch at time t1 (FIG. 11 (a)), the AT controller 24 sets a shift stage based on the shift line, and the start prohibition flag of the engine 1 is turned ON (FIG. 11). 11 (d)). In addition, the engagement pressure Apply_PRS of the engagement side engagement element that becomes the shift stage after the shift is in a supply state of a precharge pressure that loosens the clutch (FIG. 11 (f)). On the other hand, the engagement pressure Release_PRS of the disengagement-side engagement element, which is the gear position before the shift, decreases from the engagement pressure at which complete engagement is possible to the engagement pressure just before the gear ratio does not change (FIG. 11 (g)) (preprocessing).

  When the preprocessing is completed at time t2, the shift start SFTGP to the target shift stage is in a state indicating that the shift is being performed (that is, a state in which the automatic transmission 3 is started) (FIG. 11B). The fastening pressure Apply_PRS of the fastening side fastening element is gradually increased (FIG. 11 (f)), and the fastening pressure Release_PRS of the release side fastening element is gradually reduced (FIG. 11 (g)) (21 phase).

At the time t2, the coast driving force target value changes to the driving force corresponding to the target gear position with the end of the preprocessing (FIG. 11 (c)).
At time t3, when the 21 phase is completed and the switching of the automatic transmission 3 is completed, the engagement phase Apply_PRS and the engagement pressure Release_PRS of the release side engagement element are held and the inertia phase is advanced (FIG. 11). (F), (g)). Progress of the inertia phase is executed by controlling the rotational speed. That is, the control of the power source is switched from torque control to rotation speed control (region B) (31 phase).

  At this time, after completion of switching of the automatic transmission 3, the start prohibition flag of the engine 1 is canceled, the engine speed control flag SIP: 4 is once set, the engine start flag is turned ON, and the engine speed is set. The control flag SIP: 6 is set (FIG. 11 (d)). In addition, the starting target engine speed of the engine 1 is set between the current gear speed and the target gear speed (for example, (target gear speed × output speed of the second clutch 5 × set) Coefficient) or (target rotational speed at coast down shift without engine start)).

When the rotation speed of the motor 2 is controlled to the start target rotation speed and the first clutch 4 is engaged with the target engagement force, the engine 1 is started (FIG. 11 (e)). Since the engine is started in the coast state, the engine 1 is started in a state where the fuel is cut. That is, in this shift control, the drive torque of the engine 1 is always a constant friction torque (FIG. 11 (i)).
By adopting such control, the hybrid vehicle always generates a negative driving force according to the coast driving force of the target value (FIG. 11 (c)) (FIG. 11 (j)).
When the engine 1 is started, the setting is changed from the engine speed control flag SIP: 6 to the engine speed control flag SIP: 4, and the engine speed control in the normal shift control is executed (FIG. 11 (d)). .

Here, if the first clutch 4 is slipped and engaged without changing the automatic transmission 3 as described above, it slips to the (+) side of the current shift stage and is also related to the coast state. There is a possibility that a positive driving force (extrusion) may occur.
Further, when the automatic transmission 3 is not switched, if it is slipped to the (−) side with respect to the rotational state corresponding to the current shift stage, the direction of rotation change after the shift ((+) side) is opposite. Thus, the response when the engine is started and the shift control is performed is lowered. Furthermore, depending on the gear position, a one-way clutch is established, so that it cannot be slipped and engaged on the (−) side, and a starting shock occurs.

On the other hand, as in the present embodiment, the first clutch 4 is slip-engaged after completion of the switching of the automatic transmission 3, so that the rotational speed of the output shaft slips at the rotational speed corresponding to the target gear stage. It will be concluded. For this reason, even if the starting target rotational speed is set to the (+) side of the current gear position, the rotational speed of the input shaft can be set to the (−) side with respect to the rotational speed of the output shaft. The driving force can be maintained.
Further, as described above, after the automatic transmission 3 is switched, the first clutch 4 and the second clutch 5 slip at the same time by shifting to the inertia phase, and the internal rotation relationship becomes unclear and the shift shock is caused. Can be avoided.

When the rotational speed of the motor 2 reaches the set rotational speed at time t4 (FIG. 11 (e)), the inertia phase has sufficiently progressed, and thereafter the second clutch 5 on the automatic transmission 3 side. It is necessary to avoid a fastening shock when completely fastening the parts. Therefore, the control is switched to the rotational speed control (region C) that changes the rotational speed of the input shaft more gently (41 phase). In the rotation speed control at this time, control is performed so as to coincide with the target rotation speed at a slower change rate than in the region B (FIG. 11 (e)).
When the 41st phase is completed, the engine speed control flag SIP: 4 is canceled (FIG. 11D).
When the rotational speed of the motor 2 reaches the speed change target rotational speed at time t5 and the inertia phase is completed, the fastening pressure Apply_PRS of the fastening side fastening element is gradually increased until complete fastening, and the release side fastening element is fastened. The pressure Release_PRS is gradually decreased until complete release (411 phase).

When the release-side fastening element is completely released at time t6 (FIG. 11 (g)), the fastening pressure of the fastening-side fastening element is further raised to a complete fastening state (FIG. 11 (f)) (post-processing). Thereafter, the rotational speed of the engine 1 converges to the shift target rotational speed (FIG. 11 (e)). Then, the shift is completed at time t7.
As described above, the hybrid vehicle according to the present embodiment prohibits engine start when the engine 1 is stopped in the coasting state, and the engine start is prohibited, and the automatic transmission 3 is switched. And the number of rotations of the output shaft corresponds to the target shift stage. Then, after the change of the automatic transmission 3 is completed, the engine 1 is started.

  Thereby, the engine 1 is started in a state where the input / output shaft rotation speed of the automatic transmission 3 is increased by the change of the automatic transmission 3. Therefore, it is not necessary to release the first clutch 4 when the engine 1 is started, so that the negative driving force can be maintained. In addition, since the switching of the automatic transmission 3 is completed, the second clutch 5 and the first clutch 4 are not slip-engaged at the same time, so that the rotation state of the input shaft can be controlled. That is, since the rotational relationship of the input / output shafts can be set appropriately, the occurrence of a shift shock can be suppressed.

Therefore, according to the hybrid vehicle according to the present embodiment, it is possible to more appropriately start the engine and control the shift in the coast state.
In addition, since the first clutch 4 is engaged with the output shaft at a high rotational speed, the engine rotational speed at the time of starting is set between the rotational speed of the shift stage before the shift and the rotational speed of the shift stage after the shift. it can.
Therefore, the response of engine start and shift control can be improved.

In addition, after the change of the automatic transmission 3 is completed, the first clutch 4 is slip-engaged, whereby the rotation speed of the output shaft is slip-engaged at the rotation speed corresponding to the target gear stage.
For this reason, even if the starting target rotational speed is set to the (+) side of the current gear position, the rotational speed of the input shaft can be set to the (−) side with respect to the rotational speed of the output shaft. The driving force can be maintained.

Further, as described above, after the automatic transmission 3 is switched, the first clutch 4 and the second clutch 5 slip at the same time by shifting to the inertia phase, and the internal rotation relationship becomes unclear and the shift shock is caused. Can be avoided.
In the present embodiment, the motor 2 corresponds to the motor, the automatic transmission 3 corresponds to the transmission, and the integrated controller 21 corresponds to the engine start control means. The integrated controller 21 and the AT controller 24 correspond to the shift control means, and the integrated controller 21 corresponds to the start determination means.

(Effect of 1st Embodiment)
(1) The start determination means determines whether an engine start request and a transmission shift request are generated when the host vehicle travels using only the motor as a drive source and is in a coasting state. . When the determination condition is met, the engine start control means prohibits starting of the engine until the shift control means completes the change from the current shift speed to the target shift speed, and starts the engine after the change is completed. Let

Thus, the engine is started in a state where the input / output shaft rotation speed of the transmission is increased by changing the transmission. Therefore, it is not necessary to disconnect the engine from the drive wheels at the start, and the negative drive force can be maintained. Further, since the changeover of the transmission is completed, the rotation state of the input shaft of the transmission can be controlled when the engine is started, so that the occurrence of a shift shock can be suppressed.
Therefore, according to the present invention, it is possible to more appropriately perform engine start-up and shift control in the coast state.

(2) The engine start control means is a start target rotational speed between the rotational speed of the output shaft corresponding to the gear position when the engine start request is generated and the rotational speed of the output shaft corresponding to the target gear speed. Start the engine.
Therefore, the negative driving force can be maintained with respect to the output shaft even when the engine is started. Further, since the engine speed after the start is close to the speed at the time of output after the shift, the response of the shift and the engine start can be improved.

1 engine, 2 motor, 3 automatic transmission, 4 first clutch, 5 second clutch, 6 differential, 7 drive wheel, 8 inverter, 9 battery, 10 engine speed sensor, 11 motor rotation sensor, 12 input rotation sensor, 13 output rotation sensor, 14 electric sub oil pump, 15 mechanical oil pump, 18 voltage sensor, 19 current sensor, 20 accelerator sensor, 21 integrated controller, 21A required power generation torque calculation unit, 21B required engine torque calculation unit, 21C motor output Possible torque calculator, 21D Target drive torque calculator, 21Da Driver required torque calculator, 21Db Automatic control required torque calculator, 21Dc Target drive torque calculator, 21Dd Vehicle speed limiter torque calculator, 21De Final target drive torque calculator, 2 E vehicle state mode determination unit, 21Ea engine start determination processing unit, 21Eb engine stop determination processing unit, 21F engine start control unit, 21G engine stop control unit, 21H target engine torque calculation unit, 21J target motor torque calculation unit, 21K target clutch Torque calculator, 22 engine controller, 23 motor controller, 24 AT controller, 25 brake controller, 26 battery controller, 27 wheel speed sensor, 28 steering switch, 29 brake switch, 30 cruise cancel switch, 31 inter-vehicle control controller, 31A DCA control Part, 32 radar unit, 33 accelerator pedal, 34 pedal actuator, 35 meters

Claims (2)

An engine and a motor as a drive source;
A transmission that transmits the driving force from the driving source to the wheels at different gear ratios;
Engine start control means for controlling start of the engine;
Shift control means for controlling the shift of the transmission;
Start determination means for determining whether or not a start request for the engine and a shift request for the transmission are generated when the host vehicle travels using only the motor as a drive source and is in a coasting state;
With
When the start determination means determines that the engine start request and the transmission shift request are generated when the host vehicle travels using only the motor as a drive source and is in a coasting state. In addition, the engine start control means prohibits starting of the engine until the shift control means completes the change from the current shift speed to the target shift speed, and starts the engine after the change is completed. A vehicle travel control device.   The engine start control means is a start target rotation speed between a rotation speed of the output shaft corresponding to the shift speed when the engine start request is generated and a rotation speed of the output shaft corresponding to the target shift speed. The vehicle travel control device according to claim 1, wherein the engine is started.

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