JP2019034656A - Device for controlling drive torque and method for controlling drive torque for hybrid vehicle - Google Patents

Abstract

To provide a device for controlling drive torque for a hybrid vehicle that can suppress heat generated in a clutch to improve the durability thereof and prevent deterioration in fuel economy, and to provide a method for controlling drive torque.SOLUTION: A device for controlling drive torque and a method for controlling drive torque for a hybrid vehicle includes: detecting that an accelerator opening degree is held at a drive force threshold for releasing braking force or less; and lowering target drive force to predetermined drive force when the target drive force is equal to or higher than lower limit drive force that requests for restricting drive force.SELECTED DRAWING: Figure 12

Description

  The present invention relates to a drive torque control device and a drive torque control method for a hybrid vehicle.

  Patent Document 1 includes a mechanism that retains brake braking force even when the brake pedal is turned off while the vehicle is stopped. A technique for releasing the braking force is disclosed.

JP 2008-215139 A

For example, when the vehicle is driven at a high gradient and immediately before the driving force threshold, there is a possibility that the vehicle may run with a clutch slip and the clutch may generate heat and become unable to run due to a system malfunction. .
An object of the present invention is, for example, a hybrid vehicle drive torque control device capable of suppressing heat generation of a clutch, improving durability, and preventing deterioration of fuel consumption in a hybrid vehicle having clutch slip start control. It is to provide a driving torque control method.

  In order to achieve the above object, in the driving torque control device and driving torque control method for a hybrid vehicle of the present invention, it is detected that the accelerator opening is held below the driving force threshold value for releasing the brake braking force. When the target driving force is equal to or higher than the lower limit driving force requiring driving force limitation, the target driving force is reduced to a predetermined driving force.

  Thus, for example, in a hybrid vehicle having clutch slip start control, heat generation of the clutch can be suppressed, durability can be improved, and fuel consumption can be prevented from deteriorating.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an overall system diagram illustrating a rear-wheel drive hybrid vehicle according to a first embodiment. FIG. 3 is a control block diagram illustrating an arithmetic processing program in the integrated controller according to the first embodiment. It is a figure which shows the engine target steady torque map and motor generator assist torque map which are used for the calculation of target drive torque in the target drive torque calculation part of FIG. It is a figure which shows the normal mode map used for selection of the target mode in the mode selection part of FIG. It is a figure which shows the engine start-stop line map corresponding to battery SOC. It is a figure which shows the electric power generation request output map during driving | running | working used for the calculation of a target electric power generation output by the target electric power generation output calculating part of FIG. It is a figure which shows the engine characteristic of Example 1. FIG. It is a figure which shows the shift map of the automatic transmission of Example 1. FIG. 3 is a flowchart illustrating a drive torque control process according to the first embodiment. 3 is a flowchart illustrating an accelerator opening degree holding determination control process according to the first embodiment. 3 is a flowchart illustrating a target driving force holding determination control process according to the first embodiment. 3 is a time chart illustrating a drive torque control process according to the first embodiment. It is a figure which shows the brake braking force cancellation | release threshold value map of Example 1. FIG. 6 is a flowchart illustrating a drive torque control process according to the second embodiment. 6 is a flowchart illustrating a start intention determination control process according to the second embodiment. 6 is a time chart illustrating a drive torque control process according to the second embodiment. 10 is a flowchart illustrating a start intention determination control process according to a third embodiment. FIG. 10 is a diagram illustrating a driving force limit upper threshold map according to a third embodiment. 12 is a time chart illustrating a drive torque control process according to the third embodiment.

[Example 1]
FIG. 1 is an overall system diagram showing a hybrid vehicle by rear wheel drive to which the engine start control device of the first embodiment is applied. The drive system of the hybrid vehicle in the first embodiment includes an engine E that is an internal combustion engine, a first clutch CL1, a motor generator MG that functions as a drive motor, a second clutch CL2, an automatic transmission AT, and a propeller shaft. It has a PS, a differential DF, a left drive shaft DSL, a right drive shaft DSR, a left rear wheel RL (drive wheel), and a right rear wheel RR (drive wheel). Note that FL is the left front wheel and FR is the right front wheel.

The engine E is a gasoline engine, and based on a control command from an engine controller 1 described later, a valve opening of a throttle valve (not shown) is controlled. A flywheel FW is provided on the engine output shaft. Further, the engine E has a motor SSG as a starting motor. The motor SSG is connected to the crankshaft of the engine E using a belt, functions as a starter motor for starting the engine, and operates as an alternator that generates electric power as necessary.
The first clutch CL1 is a dry clutch that is interposed between the engine E and a motor generator MG as a drive motor, and can be always engaged by an urging force such as a diaphragm spring. Based on the control command, the engagement / release including slip engagement in which torque is transmitted while slipping is controlled by the control hydraulic pressure generated by the first clutch hydraulic unit 6.

The motor generator MG is a synchronous motor generator in which a permanent magnet is embedded in a rotor and a stator coil is wound around a stator, and the three-phase AC generated by the inverter 3 is generated based on a control command from a motor controller 2 described later. It is controlled by applying. The motor generator MG can operate as an electric motor that is driven to rotate by receiving power supplied from the battery 4 (hereinafter, this state is referred to as “powering”), or when the rotor is rotated by an external force. Can function as a generator that generates electromotive force at both ends of the stator coil to charge the battery 4 (hereinafter, this operation state is referred to as “regeneration”). The rotor of the motor generator MG is connected to the input shaft of the automatic transmission AT via a damper (not shown).
The second clutch CL2 is a clutch interposed between the motor generator MG and the left and right rear wheels RL and RR, and is created by the AT hydraulic control unit 8 based on a control command from the AT controller 7 described later. The control hydraulic pressure controls the fastening / release including slip fastening that transmits torque while slipping.

  The automatic transmission AT is a transmission that automatically switches a stepped gear ratio such as forward 7 speed reverse 1 speed according to the vehicle speed VSP, accelerator opening (driver's accelerator pedal operation) APO, and the like. The second clutch CL2 is not newly added as a dedicated clutch, but uses some frictional engagement elements among a plurality of frictional engagement elements that are engaged at each gear stage of the automatic transmission AT. The output shaft of the automatic transmission AT is connected to the left and right rear wheels RL and RR via a propeller shaft PS, a differential DF, a left drive shaft DSL, and a right drive shaft DSR as vehicle drive shafts. For example, a multi-plate clutch that can continuously control the oil flow rate and hydraulic pressure with a proportional solenoid is used as the second clutch CL2.

  This hybrid drive system has three travel modes according to the engaged / released state of the first clutch CL1. The first travel mode is an electric vehicle travel mode (hereinafter, abbreviated as “EV travel mode”) as a motor use travel mode in which the first clutch CL1 is disengaged and travels using only the power of the motor generator MG as a power source. It is. The second travel mode is an engine use travel mode (hereinafter, abbreviated as “HEV travel mode”) in which the first clutch CL1 is engaged and the engine E is included in the power source. In the third travel mode, the second clutch CL2 is slip-controlled while the first clutch CL1 is engaged, and the engine travel slip travel mode (hereinafter referred to as “WSC travel mode”) is performed while the engine E is included in the power source. ). This mode is a mode in which creep running can be achieved particularly when the battery SOC is low or the engine water temperature is low.

  The “HEV travel mode” has three travel modes of “engine travel mode”, “motor assist travel mode”, and “travel power generation mode”. In the “engine running mode”, the drive wheels are moved using only the engine E as a power source. In the “motor-assisted travel mode”, the drive wheels are moved using the engine E and the motor generator MG as power sources. In the “traveling power generation mode”, the motor generator MG is caused to function as a power generator while the drive wheels RR and RL are moved using the engine E as a power source. During constant speed operation or acceleration operation, motor generator MG is operated as a generator using the power of engine E. Further, during deceleration operation, braking energy is regenerated and electric power is generated by the motor generator MG and used for charging the battery 4. Further, when the vehicle is stopped, a power generation mode is employed in which the motor generator MG is operated as a generator using the power of the engine E.

  Next, the control system of the hybrid vehicle will be described. As shown in FIG. 1, the control system of the hybrid vehicle in the first embodiment includes an engine controller 1, a motor controller 2, an inverter 3, a battery 4, a first clutch controller 5, and a first clutch hydraulic unit 6. , An AT controller 7, an AT hydraulic control unit 8, a brake controller 9, an integrated controller 10, and an SSG controller SSGCU. The engine controller 1, the motor controller 2, the first clutch controller 5, the AT controller 7, the brake controller 9, the integrated controller 10, and the SSG controller SSGCU have a CAN communication line 11 that can exchange information with each other. Connected through.

The engine controller 1 inputs the discriminating cylinder from the cylinder discriminating sensor 32 and the engine speed information from the engine speed sensor 12, and according to the target engine torque command from the integrated controller 10, the engine operating point (Ne: engine speed) A command for controlling the number, Te: engine torque) is output to, for example, a throttle actuator for controlling the throttle opening of a throttle valve (not shown). Information such as the accelerator opening APO, the engine speed Ne, and the discrimination cylinder is supplied to the integrated controller 10 via the CAN communication line 11.
The SSG controller SSGCU outputs a command for operating the motor SSG as a starter motor function and an alternator function based on a command signal from the integrated controller 10.

  The motor controller 2 inputs information from the resolver 13 that detects the rotor rotation position of the motor generator MG, and inverts a command for controlling the motor operating point of the motor generator MG according to a target motor torque command from the integrated controller 10 Output to 3. The motor controller 2 monitors the battery SOC indicating the state of charge of the battery 4. The monitored battery SOC information is used as control information for the motor generator MG and is supplied to the integrated controller 10 via the CAN communication line 11.

  The first clutch controller 5 inputs sensor information from the first clutch hydraulic sensor 14 and the first clutch stroke sensor 15 and the first clutch control command from the integrated controller 10, and the first clutch hydraulic unit 6 receives the first clutch. Outputs CL1 engagement / release control command. Information on the first clutch stroke C1S is supplied to the integrated controller 10 via the CAN communication line 11.

  The AT controller 7 includes various sensor signals of the inhibitor switch 28 that outputs a range signal corresponding to the operation position of the accelerator opening sensor 16, the vehicle speed sensor 17, the second clutch hydraulic pressure sensor 18, and the select lever 27, and from the integrated controller 10. The control command is input, and the control command is output to the AT hydraulic control unit 8. The accelerator opening APO, the vehicle speed VSP, and the inhibitor switch signal are supplied to the integrated controller 10 via the CAN communication line 11. Further, the inhibitor switch signal is sent to an in-meter display 29 provided in a combination meter (not shown) to display the current range position.

  The brake controller 9 inputs sensor information from a wheel speed sensor 19 and a brake stroke sensor 20 that detect the wheel speeds of the four wheels. When the brake is depressed, the mechanical braking force (braking force by the friction brake) compensates for the regenerative braking force deficiency with respect to the required braking force required from the brake stroke BS based on the regenerative cooperative control command from the integrated controller 10. Regenerative cooperative brake control is performed.

  The integrated controller 10 is a controller for managing the energy consumption of the entire vehicle and running the vehicle with the highest efficiency, and detects the motor rotation speed sensor 21 that detects the motor rotation speed Nm and the second clutch output rotation speed N2out. A second clutch output rotational speed sensor 22, a second clutch torque sensor 23 for detecting the second clutch transmission torque capacity TCL2, a brake hydraulic pressure sensor 24, a temperature sensor 25 for detecting the temperature of the second clutch CL2, and front and rear The G sensor 26 that detects acceleration, the first clutch temperature sensor 30, the inverter temperature sensor 31, the gradient sensor 32, and information obtained via the CAN communication line 11 are input.

  The integrated controller 10 also controls the operation of the engine E according to the control command to the engine controller 1, the operation control of the motor generator MG according to the control command to the motor controller 2, and the first control command to the first clutch controller 5. Engagement / release control of clutch CL1, engagement / release control of second clutch CL2 by control command to AT controller 7, and motor control to exert starter motor function or alternator function by control command to SSG controller SSGCU Do.

  FIG. 2 is a control block diagram illustrating a control configuration in the integrated controller 10 according to the first embodiment. The integrated controller 10 executes various calculations with a control period of 10 msec, for example. The integrated controller 10 includes a target drive torque calculation unit 100, a mode selection unit 200, a target power generation output calculation unit 300, an operating point command unit 400, and a shift control unit 500.

FIG. 3 is a diagram showing a target steady torque map and a motor generator MG assist torque map of engine E used for calculation of target drive torque by the target drive torque calculation unit.
Based on the target drive torque from the target drive torque calculation unit 100, the operating point command unit 400 calculates the target engine torque and the target MG torque using the target steady drive torque map and the MG assist torque map of the engine E shown in FIG. calculate.
The driving force can be calculated from the driving torque and the gear ratio of the automatic transmission AT, and is in a proportional relationship, and either can be used substantially.

Next, the mode map will be described. FIG. 4 is a normal mode map of the first embodiment. The normal mode map has an EV travel mode, a WSC travel mode, and an HEV travel mode, and calculates the target mode from the accelerator opening APO and the vehicle speed VSP. This mode map outputs, as a target mode, a mode corresponding to the position of the operating point determined by the accelerator opening APO and the vehicle speed VSP.
FIG. 5 is a diagram showing an engine start / stop line map corresponding to the battery SOC.
Even if the EV driving mode is selected from this engine start / stop line map, if the battery SOC is below a predetermined value, the "HEV driving mode" is forcibly set to the target mode, and the battery SOC is above a predetermined value, The “EV drive mode” is output as the target mode.

  In the normal mode map of FIG. 4, the WSC → EV switching line and the HEV → EV switching line are set to a predetermined opening APO2 when viewed on the accelerator opening APO axis. Further, the HEV → EV switching line is set to a predetermined vehicle speed VSP2 when viewed from the vehicle speed VSP axis. The HEV → WSC switching line is a vehicle speed region where the rotational speed is smaller than the lower limit vehicle speed VSP1 that matches the idle rotational speed of the engine E when the automatic transmission AT is in the first speed in the region below the predetermined accelerator opening APO1. Is set to Further, since a large driving force is required in a region where the accelerator opening APO1 is equal to or greater than the predetermined accelerator opening APO1, the WSC travel mode is set up to a vehicle speed VSP1 ′ region that is higher than the lower limit vehicle speed VSP1. Note that, when the battery SOC is low and the EV travel mode cannot be achieved, the WSC travel mode is set to be selected even when starting.

  When the accelerator opening APO is large, it may be difficult to achieve the request with the engine torque Te and the motor generator torque Tmg corresponding to the engine speed near the idle speed. Here, as the engine torque Te, more torque can be output if the engine speed Ne increases. For this reason, the engine speed Ne is increased to output a larger torque. Therefore, even if the WSC travel mode is executed up to a vehicle speed higher than the lower limit vehicle speed VSP1, it is possible to make a transition from the WSC travel mode to the HEV travel mode in a short time. This case corresponds to the WSC region extended to the lower limit vehicle speed VSP1 ′ shown in FIG.

The target power generation output calculation unit 300 calculates the target power generation output from the battery SOC using the traveling power generation request output map shown in FIG.
Further, an output required to increase the engine torque Te from the current operating point to the best fuel consumption line shown in FIG. 7 is calculated, and a smaller output is added to the target engine torque as a required output compared to the target power generation output. To do.
The operating point command unit 400 uses the accelerator opening APO, the target drive torque, the target mode, the vehicle speed VSP, and the target charge / discharge power as a target for reaching the operating point, such as a transient target engine torque and target motor. The generator torque, the target second clutch transmission torque capacity, the target gear position of the automatic transmission AT, and the first clutch solenoid current command are calculated.

In addition, the operating point command unit 400 includes an engine start control unit that starts the engine E when transitioning from the EV travel mode to the HEV travel mode. The engine start control unit sets the second clutch CL2 to the second clutch transmission torque capacity in accordance with the target drive torque and sets the slip control state. Further, the motor generator MG is set to rotation speed control, and the target motor generator rotation speed is set to a value obtained by adding a predetermined slip amount to a value corresponding to the drive wheel rotation speed. In this state, the engine start control unit outputs a command to function as a starter motor to the SSG controller SSGCU and releases the first clutch CL1. Thus, engine cranking is performed while suppressing heat generation of the first clutch CL1. Then, after cranking by the motor SSG, the engine E is first ignited by ignition, and when the rotation of the engine E and the motor generator MG becomes close, a complete engagement command is output to the first clutch CL1, and then the second clutch CL2 Is completely engaged and the mode is changed to HEV travel mode.
The shift control unit 500 drives and controls the solenoid valve in the automatic transmission AT so as to achieve the target second clutch transmission torque capacity and the target shift speed according to the shift schedule shown in the shift map shown in FIG. In the shift map, a target gear position is set in advance based on the vehicle speed VSP and the accelerator opening APO.

Next, the driving performed by the operating point command unit 400 in the integrated controller 10 when starting the vehicle by depressing the accelerator pedal from the state where the driver lifts his foot from the brake pedal and the braking force is maintained while the vehicle is stopped on the uphill road The torque control process will be described.
FIG. 9 is a flowchart illustrating a drive torque control process according to the first embodiment.

In step S1, a target driving force is calculated from the target driving torque.
In step S2, it is determined whether or not the calculated target driving force is greater than or equal to a predetermined value Fmin. When the calculated target driving force is greater than or equal to the predetermined value Fmin, the process proceeds to step S3, and when the target driving force is less than the predetermined value Fmin, the process proceeds to step S6.
Fmin is set as the driving force limit start lower limit threshold value, but may be a value at which the temperature of the starting clutch is saturated below the upper limit temperature even if the driving force is continuously output at a predetermined rotation.
In step S3, it is determined whether or not an accelerator opening degree holding determination described later is ON. When the accelerator opening hold determination is ON, the process proceeds to step S4, and when the accelerator opening hold determination is not ON, the process proceeds to step S6.
In step S4, it is determined whether or not a target driving force holding determination described later is ON. When the target driving force holding determination is ON, the process proceeds to step S5, and when the target driving force holding determination is not ON, the process proceeds to step S6.
In step S5, the target driving force is limited to a predetermined value equal to or lower than the driving force limit start lower limit driving force, and is reduced.
In step S6, a change rate process is performed after returning the target driving force to the target driving torque.
This flowchart is repeated to perform drive torque control processing.
The predetermined value below the driving force limit start lower limit driving force is set differently for starting by the motor generator MG having high driving force responsiveness and starting by the engine E that performs the slip start of the second clutch CL2. That is, in the case of starting by the motor generator MG, the predetermined value of the target driving force can be further reduced.

  FIG. 10 is a flowchart illustrating an accelerator opening degree holding determination control process according to the first embodiment.

In step S11, the accelerator opening APO is calculated by differentiating the accelerator opening APO.
In step S12, it is determined whether or not the calculated accelerator opening speed ΔAPO is less than a predetermined value dAPO_in. When the calculated accelerator opening speed ΔAPO is less than the predetermined value dAPO_in, the process proceeds to step S13, and when the calculated accelerator opening speed ΔAPO is equal to or higher than the predetermined value dAPO_in, the process proceeds to step S16.
In step S13, the timer starts counting.
In step S14, it is determined whether or not the timer time is equal to or longer than a predetermined time tAPO_in. When the timer time is equal to or longer than the predetermined time tAPO_in, the process proceeds to step S15, and when the timer time is less than the predetermined time tAPO_in, the process proceeds to step S16.
In step S15, it is determined that the accelerator opening is held, and the accelerator opening hold determination is set to ON.
In step S16, the accelerator opening hold determination = OFF state is maintained.
This flowchart is repeated, and the accelerator opening degree holding determination is turned ON / OFF.

  FIG. 11 is a flowchart illustrating a target driving force holding determination control process for detecting that the target driving force according to the first embodiment is the accelerator opening equivalent driving force.

In step S21, ΔF is calculated by differentiating the target driving force.
In step S22, it is determined whether or not the calculated ΔF is less than dF_in. When the calculated ΔF is less than dF_in, the process proceeds to step S23, and when the calculated ΔF is equal to or greater than dF_in, the process proceeds to step S26.
In step S23, the timer starts counting.
In step S24, it is determined whether or not the timer time is equal to or longer than a predetermined time tF_in. When the timer time is equal to or longer than the predetermined time tF_in, the process proceeds to step S25, and when the timer time is less than the predetermined time tF_in, the process proceeds to step S26.
In step S25, it is determined whether or not the target driving force is detected to detect that the target driving force has reached the accelerator opening equivalent driving force, and the target driving force holding determination is set to ON.
In step S26, the target driving force holding determination flag = OFF state is maintained.
This flowchart is repeated, and ON / OFF determination of target driving force holding determination is performed.

FIG. 12 is a time chart showing the drive torque control process of the first embodiment.
Moreover, the hybrid driving, that is, the start by the engine E starting state is shown.
Accordingly, in a hybrid vehicle having clutch slip start control, heat generation of the clutch can be suppressed, durability can be improved, and fuel consumption can be prevented from deteriorating. Further, by limiting the conditions for reducing the target driving force to a predetermined torque, it is possible to improve the acceleration feeling when starting uphill from a system state in which the driving force does not decrease.
The horizontal axis is time.
From the top, accelerator opening APO corresponding to the driver's accelerator pedal operation, accelerator opening speed ΔAPO, accelerator hold determination control processing, target drive force hold determination that detects that the target drive force has reached the accelerator opening equivalent drive force The change of control processing is shown.
The bottom shows changes in brake braking force, accelerator opening equivalent driving force, pre-limit target driving force, and target driving force of the first embodiment.
The pre-restriction target driving force is a target driving force set corresponding to the accelerator opening equivalent driving force.
The left vertical axis is the driving force, and the right vertical axis is the brake braking force.
The change in braking force is indicated by a solid line.
On the left vertical axis, a driving force limit start lower limit threshold value as Fmin and a driving force threshold value as a brake braking force release threshold value are indicated by broken lines.
The brake braking force release threshold is a value determined in accordance with the road gradient based on the brake braking force release threshold map shown in FIG.
Regarding the change in driving force, the solid line indicates the driving force corresponding to the accelerator opening, the broken line indicates the target driving force, and the alternate long and short dash line indicates the target driving force before restriction.
The driving force can be calculated from the driving torque and the gear ratio of the automatic transmission AT, and is in a proportional relationship, and either can be used substantially.

First, accelerator opening APO corresponding to the driver's accelerator pedal operation, accelerator opening speed ΔAPO, accelerator hold determination control processing, target drive force hold determination control for detecting that the target drive force has become the accelerator opening equivalent drive force A change in processing will be described.
At time t0, in a state where the vehicle is stopped on the slope, the driver removes his / her foot from the brake pedal and starts depressing the accelerator pedal.
Even if the driver removes his / her foot from the brake pedal, the braking force is maintained.
At time t1, the driver stops depressing the accelerator pedal and holds the accelerator pedal depression amount (accelerator opening APO) until time t5. After time t5, the accelerator pedal is again depressed, and at time t7, the accelerator pedal depression amount (accelerator opening APO) is held.
At time t2, the accelerator holding determination control process described above is performed to determine whether or not the driver holds the accelerator pedal. In this time chart, ΔAPO <dAPO_in and (t2−t1) ≧ tAPO_in is established, and it is determined that the accelerator opening hold determination = ON.
At time t4, the target driving force holding determination is performed to detect that the target driving force described above becomes the accelerator opening equivalent driving force. In the case of this time chart, ΔF <dF_in (t4-t3) ≧ tF_in is established, and it is determined that the target driving force holding determination = ON.
Furthermore, since the target driving force corresponding to the accelerator opening is equal to or greater than the driving force limit start lower limit threshold Fmin, and the accelerator opening retention determination = ON and the target driving force retention determination = ON are established, the target driving force is converted into the driving force. The driving force is limited to a predetermined driving force that is equal to or lower than the limit start lower limit threshold value.

Next, changes in brake braking force, accelerator opening equivalent driving force, pre-limit target driving force, and target driving force will be described.
The brake braking force is held from time t0 to time t8. At time t8, release of the held brake braking force is started, and the braking force is gradually reduced.
The accelerator opening equivalent driving force exceeds the driving force limit start lower limit threshold Fmin from time t0 to time t1, increases, becomes constant until time t5, again exceeds the brake braking force release threshold, and increases until time t7, It is constant after time t7. That is, it corresponds to a change in the accelerator opening APO.
The target driving force before the limit increases from time t0 with a delay with respect to the driving force equivalent to the accelerator opening, exceeds the driving force limit start lower limit threshold, and coincides with the driving force equivalent to the accelerator opening at time t3. Until t5, it remains constant as with the accelerator opening equivalent driving force.After time t5, it increases at a different slope from the accelerator opening equivalent driving force, exceeds the brake braking force release threshold at time t6, and again at time t8. Thus, it corresponds to the driving force equivalent to the accelerator opening.
The target driving force of the first embodiment moves in the same manner as the target driving force before restriction from time t0 to time t4. At time t4, the target driving force is equal to or greater than the driving force restriction start lower limit threshold Fmin, the accelerator holding determination = ON, and the target driving force holding determination that detects that the target driving force has become the driving force equivalent to the accelerator opening = ON Is established and the target driving force whose response has been delayed due to the rate of change, etc., can be determined to have caught up with the driving force equivalent to the accelerator opening. I am letting.
This predetermined value is maintained until time t6, at time t6 when the target driving force before the restriction exceeds the braking braking force release threshold, the restriction on the target driving force is released, and the increase starts at the rate of change C described later, At t8, the brake braking force release threshold is exceeded, and then it coincides with the accelerator opening equivalent driving force.
Therefore, at the time t8 when the target driving force exceeds the brake braking force release threshold value, the release of the held brake braking force is started as described above, and the vehicle is started while gradually reducing the braking force.
By exceeding the driving force limit start lower limit threshold and using the target driving force holding determination that detects that the accelerator opening degree holding determination and the target driving force have become the driving force equivalent to the accelerator opening amount, the brake force cancellation step is exceeded. Therefore, it is possible to prevent the target driving force from being erroneously limited and lowered when the constant driving force is kept constant.
Note that the driving force limit start lower limit threshold is exceeded, the accelerator holding determination = ON, and the target driving force holding determination = ON is detected to detect that the target driving force has reached the driving force equivalent to the accelerator opening, and is held once. Even if the condition is satisfied again when the release of the brake braking force that has been started is started, reducing the target driving force to a predetermined value below the driving force limit start lower limit threshold will cause a response delay at the start In order not to let it happen, it can be prohibited.

As described above, in the first embodiment, the following operational effects can be obtained.
(1) A first clutch capable of connecting / disconnecting the engine and the drive motor, a second clutch capable of connecting / disconnecting the drive motor and the drive wheel, and brake braking force even when the brake pedal is released while the vehicle is stopped And a mechanism for releasing the brake braking force when the accelerator opening increases beyond the driving force threshold that is set larger as the road gradient when the vehicle is stopped increases. A device,
When it is detected that the accelerator opening is held below the driving force threshold value for releasing the brake braking force, and the target driving force is equal to or higher than the start lower limit driving force for starting the driving force limitation, the target driving force is set to the driving force. The driving force is limited to a predetermined driving force that is equal to or lower than the lower limit starting driving force.
Therefore, in the hybrid vehicle equipped with the slip start control of the second clutch CL2 that is the start clutch, when starting with the engine E started uphill, the heat generation of the second clutch CL2 can be suppressed, and the durability is improved. Can be improved.
Similarly, in the case of starting by the motor generator MG, it is possible to suppress deterioration in fuel consumption due to an increase in power consumption due to the torque output state of the motor generator MG being continued without starting the vehicle.

(2) A driving force limit start lower limit driving force Fmin that detects that the accelerator opening is held with a driving force that is equal to or less than a brake braking force release threshold that releases the braking force, and that the target driving force starts to limit the driving force. As described above, when it is further detected that the target driving force becomes the accelerator opening equivalent driving force, the target driving force is limited to a predetermined driving force equal to or lower than the driving force restriction start lower limit driving force and is reduced.
Therefore, if the accelerator opening is made constant after the accelerator opening is stepped over the driving force threshold for releasing the brake braking force, the target driving force is limited when the accelerator driving determination is only ON and the target driving force is limited. Since it is delayed due to the rate of change, etc., the target driving force is not the target, so it was confirmed that the target driving force became the driving force equivalent to the accelerator opening, and the target driving force was limited. The driving force can be prevented from being reduced.

(3) The detection of holding the accelerator opening is that the accelerator opening speed is not more than a predetermined value and continues for a predetermined time, and the detection that the target driving force has become the driving force equivalent to the accelerator opening is that the differential value of the target driving force is Less than a predetermined value and continued for a predetermined time.
Therefore, it can detect reliably.

(4) The detection that the target driving force is the accelerator opening equivalent driving force is that the differential value of the target driving force is not more than a predetermined value and continues for a predetermined time.
Therefore, it can detect reliably.

(5) The target driving force that is limited and reduced to a predetermined driving force is increased when the pre-restricting target driving force corresponding to the accelerator opening equivalent driving force reaches the brake braking force release threshold.
Therefore, it is possible to increase the target driving force that is limited and reduced at an accurate timing.

(6) When the target driving force is reduced to a predetermined driving force, the vehicle is provided with a slip start control such as a start clutch and travels in an engine start state.
Therefore, by limiting the conditions for reducing the target driving force to a predetermined torque, it is possible to improve the acceleration feeling when starting uphill from a system state in which the driving force does not decrease.

(7) When the target driving force is reduced to the predetermined driving force, the predetermined driving force equal to or lower than the driving force restriction start lower limit driving force is a different value in the EV traveling mode and the HEV traveling mode.
Therefore, the start by the motor generator MG having high driving force response and the start by the engine E that performs the slip start of the second clutch CL2 are set differently. In other words, in the case of starting by the motor generator MG, the predetermined value of the target driving force can be further reduced, and the predetermined driving force to be reduced is switched in the system operation state to ensure clutch durability and during EV The motor power consumption can be reduced.

(8) When the target driving force exceeds the driving force limit start lower limit threshold, the accelerator holding determination = ON and the target driving force holding determination = ON is established, and the release of the held braking braking force is started again. Even if the condition is satisfied, it is prohibited to limit the target driving force to a predetermined value that is equal to or less than the driving force restriction start lower limit threshold value.
Therefore, the responsiveness at the time of start can be improved.

FIG. 14 is a flowchart illustrating a drive torque control process according to the second embodiment.
This drive torque control process is provided in addition to the drive torque control process of the first embodiment.

In step S31, it is determined whether the target driving force is being limited. When the target driving force is being limited, the process proceeds to step S32, and when the target driving force is not being limited, the process proceeds to step 37.
In step S32, the driver's intention to start is detected. Details will be described later.
In step S33, it is determined whether or not the driver intends to start. When the driver intends to start, the process proceeds to step S34, and when the driver does not intend to start, the process proceeds to step S37.
In step S34, release of the limited target driving force is started.
In step S35, it is determined whether or not the target driving force is equal to or less than the gradient balancing torque. When the target driving force is equal to or less than the gradient balancing torque, the process proceeds to step S36, and when the target driving force is not equal to or less than the gradient balancing torque, the process proceeds to step S38.
In step S36, A is selected as the rate of change for returning the target driving force.
In step S37, C is selected as the rate of change for returning the normal target driving force.
In step S38, B is selected as the rate of change for returning the target driving force.
The relationship between the change rates is change rate A> change rate C> change rate B. The change rate B and the change rate C may be the same.
In step S39, after the target driving force is returned to the target driving torque, change rate processing is performed.
This flowchart is repeated to perform drive torque control processing.

  FIG. 15 is a flowchart illustrating a start intention determination control process according to the second embodiment.

In step S41, the accelerator opening APO is differentiated to calculate the accelerator opening speed ΔAPO. In step S42, it is determined whether or not the calculated accelerator opening speed ΔAPO is equal to or higher than dAPO_out. When the calculated accelerator opening speed ΔAPO is equal to or higher than dAPO_out, the process proceeds to step S43, and when the calculated accelerator opening speed ΔAPO is not equal to or higher than dAPO_out, the process proceeds to step S46.
In step S43, the timer starts counting.
In step S44, it is determined whether the timer time is equal to or longer than a predetermined time tAPO_out. When the timer time is equal to or longer than the predetermined time tAPO_out, the process proceeds to step S45, and when the timer time is less than the predetermined time tAPO_out, the process proceeds to step S46.
In step S45, it is determined that start intention determination = ON (start intention is present).
In step S46, it is determined that start intention determination = OFF (no start intention).
This flowchart is repeated to perform a start intention determination control process.

FIG. 16 is a time chart showing the drive torque control process of the second embodiment.
Moreover, the hybrid driving, that is, the start by the engine E starting state is shown.
Further, the timing for releasing and increasing the limited target driving force was performed when the pre-restricted target driving force reached the brake braking force release threshold in the first embodiment, but in the second embodiment,
In addition, in order to prioritize the start intention determination, the determination is performed when ΔAPO ≧ dAPO_out and (t6-t5) ≧ tAPO_out are satisfied.
The horizontal axis is time.
From above, changes in the accelerator opening APO, the accelerator opening speed ΔAPO, the accelerator hold determination control process, the target driving force hold determination control process, and the start intention determination control process corresponding to the driver's accelerator pedal operation are shown.
The bottom shows changes in brake braking force, accelerator opening equivalent driving force, target driving force before restriction, and target driving force of the second embodiment.
The left vertical axis is the driving force, and the right vertical axis is the brake braking force.
The change in braking force is indicated by a solid line.
On the left vertical axis, a driving force limit start lower limit threshold value as Fmin and a driving force threshold value as a brake braking force release threshold value are indicated by broken lines.
The brake braking force release threshold is a value determined in accordance with the road gradient based on the brake braking force release threshold map shown in FIG.
Regarding the change in the driving force, the solid line indicates the driving force corresponding to the accelerator opening, the broken line indicates the target driving force of the second embodiment, and the alternate long and short dash line indicates the target driving force before restriction.
The two-dot chain line indicates the target driving force of the first embodiment.
The driving force can be calculated from the driving torque and the gear ratio of the automatic transmission AT, and is in a proportional relationship, and either can be used substantially.

First, changes in the accelerator opening APO, the accelerator opening speed ΔAPO, the accelerator hold determination control process, the target driving force hold determination control process, and the start intention determination control process corresponding to the driver's accelerator pedal operation will be described.
At time t0, in a state where the vehicle is stopped on the slope, the driver removes his / her foot from the brake pedal and starts depressing the accelerator pedal.
Even if the driver removes his / her foot from the brake pedal, the braking force is maintained.
At time t1, the driver stops depressing the accelerator pedal and holds the accelerator pedal depression amount (accelerator opening APO) until time t5. After time t5, the accelerator pedal is again depressed, and at time t8, the accelerator pedal depression amount (accelerator opening APO) is held.
At time t2, the accelerator holding determination control process described above is performed to determine whether or not the driver holds the accelerator pedal. In this time chart, ΔAPO <dAPO_in and (t2−t1) ≧ tAPO_in is established, and it is determined that the accelerator opening hold determination = ON.
At time t4, the target driving force holding determination is performed to detect that the target driving force described above becomes the accelerator opening equivalent driving force. In the case of this time chart, ΔF <dF_in (t4-t3) ≧ tF_in is established, and it is determined that the target driving force holding determination = ON.
Furthermore, since the target driving force corresponding to the accelerator opening is equal to or greater than the driving force limit start lower limit threshold Fmin, and the accelerator opening retention determination = ON and the target driving force retention determination = ON are established, the target driving force is converted into the driving force. The driving force is limited to a predetermined driving force that is equal to or lower than the limit start lower limit threshold value.
At time t6, the above-described start intention determination is performed to determine whether or not the driver intends to start, and to determine whether or not the restriction on the target driving force is to be released. In the case of this time chart, it is determined that the driver intends to start, and it is determined whether to release the restriction on the target driving force.

Next, changes in brake braking force, accelerator opening equivalent driving force, pre-limit target driving force, target driving force in the second embodiment, and target driving force in the first embodiment will be described.
The brake braking force is held from time t0 to time t8. At time t8, release of the held brake braking force is started, and the braking force is gradually reduced.
The accelerator opening equivalent driving force exceeds the driving force limit start lower limit threshold Fmin from time t0 to time t1, increases, becomes constant until time t5, again exceeds the brake braking force release threshold, and increases until time t8, It is constant after time t8. That is, it corresponds to a change in the accelerator opening APO.
The target driving force before the limit increases from time t0 with a delay with respect to the driving force equivalent to the accelerator opening, exceeds the driving force limit start lower limit threshold, and coincides with the driving force equivalent to the accelerator opening at time t3. Until t5, it remains constant like the accelerator opening equivalent driving force.After time t5, it increases at a different slope from the accelerator opening equivalent driving force, exceeds the brake braking force release threshold at time t7, and again at time t9. Thus, it corresponds to the driving force equivalent to the accelerator opening.
The target driving force according to the second embodiment moves in the same manner as the target driving force before restriction from time t0 to time t4. At time t4, the target driving force is equal to or greater than the driving force restriction start lower limit threshold Fmin, the accelerator holding determination = ON, and the target driving force holding determination that detects that the target driving force has become the driving force equivalent to the accelerator opening = ON Is established and the target driving force whose response has been delayed due to the rate of change, etc., can be determined to have caught up with the driving force equivalent to the accelerator opening. I am letting.
This predetermined value is maintained until time t6, and ΔAPO ≧ dAPO_out, (t6-t5) ≧ tAPO_out is established, and the target driving force changes at time t6 when it is determined that start intention determination = ON (start intention) It linearly increases at a rate A to a gradient-balanced driving force α, and then increases at a small change rate B of the slope, and coincides with the accelerator opening equivalent driving force at time t10.
The gradient balanced driving force is a driving force that does not start (accelerate) the vehicle in response to the road gradient.
For this reason, the target driving force of the second embodiment increases linearly to the gradient balancing driving force α at the rate of change A from time t6 when it is determined that starting intention determination = ON (starting intention is present), and thereafter, a small inclination When the brake braking force release threshold is reached at time t8, the release of the brake braking force that has been held is started, and the vehicle is started by gradually reducing the braking force as described above. Let
Further, as described above, the target driving force of the first embodiment moves in the same manner as the target driving force of the second embodiment from time t0 to time t6.
At time t4, the target driving force is equal to or greater than the driving force limit start lower limit threshold Fmin, the accelerator holding determination = ON, and the target driving force holding determination that detects that the target driving force has reached the accelerator opening equivalent driving force = ON Is established and the target driving force whose response has been delayed due to the rate of change, etc., can be determined to have caught up with the driving force equivalent to the accelerator opening. I am letting.
This predetermined value is maintained until time t7, and at time t7 when the pre-restricted target driving force exceeds the brake braking force release threshold, the target driving force of Example 1 increases at the rate of change C, and the brake braking force is released at t11. When the threshold value is exceeded, the brake braking force that has been held is released, and the braking force is gradually reduced to start the vehicle. Thereafter, it coincides with the accelerator opening equivalent driving force.
That is, the release of the brake braking force that is held corresponds to the driver's intention to start, and the time until the vehicle starts in the second embodiment can be made faster than that in the first embodiment.
Further, the timing for releasing and increasing the limited target driving force was performed when the pre-restricting target driving force reached the brake braking force release threshold, but in addition to this, ΔAPO ≧ dAPO_out as the start intention determination , (T6−t5) ≧ tAPO_out is performed even when it is satisfied, and the limited target driving force can be reliably released.

As described above, in the second embodiment, the following operational effects can be obtained in addition to the effects of the first embodiment.
(1) A start intention is detected, and when there is a start intention, the lowered target driving force is returned to the gradient balanced driving force with a quick response.
Therefore, when starting on an uphill road, the vehicle does not accelerate up to the gradient balanced driving force, and the vehicle is stopped by the braking force, so even if the response of the target driving force is set earlier than usual, the vehicle behavior Is less affected. As a result, the brake braking force release threshold value of the braking force with the target driving force maintained can be reached quickly, and the braking force can be released quickly, so that the vehicle can start moving quickly when starting.

(2) When a start intention is detected and the start intention is present, the lowered target driving force is returned to the gradient balanced driving force with an early response, and when the gradient balancing driving force is exceeded, the response is returned with a response slower than the above response. .
Therefore, it is possible to suppress a sudden release of the brake braking force, to reach the brake braking force release threshold of the brake braking force at which the target driving force is maintained, and to quickly release the braking force. The vehicle can start moving quickly and can start smoothly.

(3) Start intention detection means that the accelerator opening speed is equal to or higher than a predetermined value and continues for a predetermined time.
Therefore, it can detect reliably.

(4) The timing for releasing and increasing the limited target driving force was performed when the target driving force before the limit reached the brake braking force release threshold, but in addition to this, ΔAPO ≧ This is also performed when dAPO_out, (t6-t5) ≧ tAPO_out is established.
Therefore, the limited target driving force can be reliably released.

FIG. 17 is a flowchart illustrating a start intention determination control process according to the third embodiment.
This drive torque control process is provided in addition to the drive torque control process of the first embodiment.

In step S51, the accelerator opening APO is differentiated to calculate the accelerator opening speed ΔAPO. In step S52, it is determined whether or not the calculated accelerator opening speed ΔAPO is equal to or higher than dAPO_out. When the calculated accelerator opening speed ΔAPO is equal to or higher than dAPO_out, the process proceeds to step S53, and when the calculated accelerator opening speed ΔAPO is not equal to or higher than dAPO_out, the process proceeds to step S56.
In step S53, the timer starts counting.
In step S54, it is determined whether or not the timer time is equal to or longer than a predetermined time tAPO_out. When the timer time is equal to or longer than the predetermined time tAPO_out, the process proceeds to step S55, and when the timer time is less than the predetermined time tAPO_out, the process proceeds to step S6.
In step S55, it is determined that start intention determination = ON (start intention is present).
In step S56, it is determined whether or not the pre-limit target driving force is equal to or greater than the driving force limit upper threshold. When it is equal to or greater than the target driving force driving force limit upper limit threshold before limitation, the process proceeds to step S57. When it is not equal to or greater than the target driving force driving force limit upper limit threshold before limitation, the process proceeds to step S58.
The driving force limit upper limit threshold is a value determined in accordance with the road gradient based on the driving force limit upper limit threshold map shown in FIG.
In step S57, it is determined that start intention determination = ON (start intention is present).
In step S58, it is determined that start intention determination = OFF (no start intention).
This flowchart is repeated to perform a start intention determination control process.

FIG. 19 is a time chart showing the drive torque control process of the third embodiment.
Moreover, the hybrid driving, that is, the start by the engine E starting state is shown.
Further, the timing of releasing and increasing the limited target driving force is performed when ΔAPO ≧ dAPO_out, (t6-t5) ≧ tAPO_out as start intention determination is established in the second embodiment. In addition to this, it is also performed when the target driving force before limitation reaches the driving force limitation upper limit threshold.
It should be noted that the time when the pre-restricted target driving force at which the restricted target driving force is released and increased reaches the brake braking force release threshold is omitted.
The horizontal axis is time.
From above, changes in the accelerator opening APO, the accelerator opening speed ΔAPO, the accelerator hold determination control process, the target driving force hold determination control process, and the start intention determination corresponding to the driver's accelerator pedal operation are shown.
The bottom shows changes in brake braking force, accelerator opening equivalent driving force, target driving force before restriction, and target driving force of the third embodiment.
The left vertical axis is the driving force, and the right vertical axis is the brake braking force.
The change in braking force is indicated by a solid line.
On the left vertical axis, a driving force limit start lower limit threshold value as Fmin and a driving force threshold value as a brake braking force release threshold value are indicated by broken lines.
The brake braking force release threshold is a value determined in accordance with the road gradient based on the brake braking force release threshold map shown in FIG.
Regarding the change in the driving force, the solid line indicates the driving force corresponding to the accelerator opening, the broken line indicates the target driving force of the third embodiment, and the alternate long and short dash line indicates the target driving force before restriction.
The driving force can be calculated from the driving torque and the gear ratio of the automatic transmission AT, and is in a proportional relationship, and either can be used substantially.

First, changes in the accelerator opening APO, the accelerator opening speed ΔAPO, the accelerator hold determination control process, and the target driving force hold determination control process corresponding to the driver's accelerator pedal operation will be described.
At time t0, with the vehicle stopped on the slope, the driver removes his / her foot from the brake pedal and slowly depresses the accelerator pedal at a very slow accelerator opening speed ΔAPO.
Even if the driver removes his / her foot from the brake pedal, the braking force is maintained.
At time t1, the driver stops the depression of the accelerator pedal and holds the amount of depression of the accelerator pedal (accelerator opening APO) until time ta. After the time ta, the accelerator pedal depression is started again very slowly, and the accelerator pedal depression amount (accelerator opening APO) is held at the time tc.
At time t2, the accelerator holding determination control process described above is performed to determine whether or not the driver holds the accelerator pedal. In this time chart, ΔAPO <dAPO_in and (t2−t1) ≧ tAPO_in is established, and it is determined that the accelerator opening hold determination = ON.
At time t4, the target driving force holding determination is performed to detect that the target driving force described above becomes the accelerator opening equivalent driving force. In the case of this time chart, ΔF <dF_in (t4-t3) ≧ tF_in is established, and it is determined that the target driving force holding determination = ON.
Furthermore, since the target driving force corresponding to the accelerator opening is equal to or greater than the driving force limit start lower limit threshold Fmin, and the accelerator opening retention determination = ON and the target driving force retention determination = ON are established, the target driving force is converted into the driving force. The driving force is limited to a predetermined driving force that is equal to or lower than the limit start lower limit threshold value.
In the intention to start, since the accelerator opening speed ΔAPO is extremely small, ΔAPO ≧ dAPO_out is not satisfied, but at time tb, the target driving force before the limit exceeds the driving force limit upper limit threshold as described later. It is determined that intention determination = ON.

Next, changes in brake braking force, accelerator opening equivalent driving force, pre-limit target driving force, and target driving force of the third embodiment will be described.
The brake braking force is held from time t0 to time td. At time td, the release of the held brake braking force is started, and the braking force is gradually reduced.
The driving force equivalent to the accelerator opening exceeds the driving force limit start lower limit threshold from time t0 to time t1, increases, becomes constant until time ta, increases again to the time td after exceeding the braking force release threshold, and After td, it is constant. That is, it corresponds to a change in the accelerator opening APO.
The target driving force before the limit increases from time t0 with a delay with respect to the driving force equivalent to the accelerator opening, exceeds the driving force limit start lower limit threshold, and coincides with the driving force equivalent to the accelerator opening at time t3. Up to ta, the driving force is constant like the accelerator opening equivalent driving force. After time ta, the driving force increases with the same inclination as the accelerator opening equivalent driving force, and moves in agreement with the accelerator opening equivalent driving force.
At time t4, the target driving force is equal to or greater than the driving force restriction start lower limit threshold Fmin, the accelerator holding determination = ON, and the target driving force holding determination that detects that the target driving force has become the driving force equivalent to the accelerator opening = ON Therefore, it can be determined that the target driving force whose response has been delayed due to the rate of change, etc. has caught up with the driving force equivalent to the accelerator opening, so the target driving force is reduced to a predetermined value below the driving force limit start lower limit threshold value. Yes.
This predetermined value is maintained until time tb, and the target driving force of the third embodiment is used at time tb when starting intention determination = ON (starting intention is present) because the target driving force before the limit exceeds the driving force limit upper threshold. The force increases linearly to the gradient balanced driving force α at the rate of change A, and then increases at the rate of change B with a small slope, and coincides with the accelerator opening equivalent driving force at time te.
The gradient balanced driving force is a driving force that does not start (accelerate) the vehicle in response to the road gradient.
Therefore, at the time td when the target driving force exceeds the driving force limit upper limit threshold value, as described above, the release of the brake braking force that has been held is started, and the vehicle is started while gradually reducing the braking force.
By using the start intention determination based on the driving force limit upper limit threshold, it is possible to prevent the target driving force that has been limited by mistake from being released when the accelerator pedal can be continuously depressed at a slow accelerator opening speed ΔAPO. it can.
Moreover, the timing for releasing and increasing the limited target driving force was performed when ΔAPO ≧ dAPO_out, (t6-t5) ≧ tAPO_out as the start intention determination was established, but in addition to this, the target before limitation This is performed even when the driving force reaches the driving force limit upper threshold value, and the limited target driving force can be reliably released.

As described above, in the third embodiment, the following operational effects can be obtained in addition to the effects of the first and second embodiments.
(1) Start intention detection means that the target driving force before restriction corresponding to the accelerator opening equivalent driving force is equal to or greater than the driving force restriction upper limit threshold.
Therefore, if the target driving force before the limit exceeds the driving force limit upper threshold even if the accelerator is depressed slowly so that the intention to start due to the accelerator opening speed ΔAPO is not detected, the target driving force that has been limited and reduced can be restored. , You can prevent you can not start on the slope.
(2) The timing for releasing and increasing the limited target driving force is the time when ΔAPO ≧ dAPO_out, (t6-t5) ≧ tAPO_out as start intention determination is satisfied, and the target driving force before limitation is the driving force limitation. Even when the upper threshold is reached.
Therefore, the limited target driving force can be reliably released.

[Other Examples]
Although the present invention has been described based on the embodiments, the specific configuration may be other configurations. For example, in the embodiment, the FR type hybrid vehicle has been described. However, an FF type hybrid vehicle may be used.

1 Engine controller
2 Motor controller
10 Integrated controller
CL1 1st clutch
CL2 2nd clutch
E engine
MG motor generator
RR, RL drive wheel

Claims (12)

The first clutch capable of connecting / disconnecting the engine and the drive motor, the second clutch capable of connecting / disconnecting the drive motor and the drive wheel, and the brake braking force even when the brake pedal is released while the vehicle is stopped And a mechanism for releasing the brake braking force when the accelerator opening increases beyond the driving force threshold as a brake braking force release threshold that is set to be larger as the road gradient when the vehicle is stopped is larger. A vehicle drive torque control device comprising:
When it is detected that the accelerator opening is held below the driving force threshold value for releasing the brake braking force, and the target driving force is detected to be equal to or higher than the driving force limit start lower limit driving force for starting the driving force limit, Reducing the driving force to a predetermined driving force equal to or lower than the driving force limit start lower limit driving force;
A drive torque control device for a hybrid vehicle characterized by the above. In the hybrid vehicle drive torque control device according to claim 1,
When the target driving force is reduced to a predetermined driving force, it is detected that the accelerator opening is held below a driving force threshold value for releasing the brake braking force, and the target driving force starts driving force limiting. Detecting the limit start lower limit driving force or more and detecting that the target driving force is the accelerator opening equivalent driving force,
A drive torque control device for a hybrid vehicle characterized by the above. The drive torque control device for a hybrid vehicle according to claim 1 or 2,
The holding detection of the accelerator opening is that the accelerator opening speed is a predetermined value or less and continues for a predetermined time.
A drive torque control device for a hybrid vehicle characterized by the above. The drive torque control device for a hybrid vehicle according to claim 2,
The detection that the target driving force is the accelerator opening equivalent driving force is that the differential value of the target driving force is not more than a predetermined value and continues for a predetermined time.
A drive torque control device for a hybrid vehicle characterized by the above. In the hybrid vehicle drive torque control device according to claim 1,
The target driving force reduced to the predetermined driving force is increased when the target driving force before restriction corresponding to the accelerator opening equivalent driving force reaches the brake braking force release threshold value,
A drive torque control device for a hybrid vehicle characterized by the above. The drive torque control device for a hybrid vehicle according to claim 2,
It is detected that the accelerator opening is held below the driving force threshold value for releasing the braking force, the target driving force is detected to be equal to or higher than the driving force limit start lower limit driving force for starting driving force limitation, and the target When it is detected that the driving force is equivalent to the accelerator opening and the target driving force is reduced to a predetermined driving force, a vehicle having a slip start control such as a start clutch and running in an engine start state is provided. set to target,
A drive torque control device for a hybrid vehicle characterized by the above. In the hybrid vehicle drive torque control device according to claim 1,
The predetermined driving force equal to or less than the driving force limit start lower limit driving force is a different value in the EV traveling mode and the HEV traveling mode.
A drive torque control device for a hybrid vehicle characterized by the above. In the hybrid vehicle drive torque control device according to claim 1,
When the start intention is detected and the start intention is present, the lowered target driving force is returned to the gradient balanced driving force with a quick response.
A drive torque control device for a hybrid vehicle characterized by the above. The drive torque control device for a hybrid vehicle according to claim 8,
When the intention to start is detected and the intention to start is present, the lowered target driving force is returned to the gradient balanced driving force with a quick response, and the gradient balanced driving force is returned with a response slower than the response.
A drive torque control device for a hybrid vehicle characterized by the above. The drive torque control device for a hybrid vehicle according to any one of claims 8 to 9,
The start intention detection is that the accelerator opening speed is a predetermined value or more and continues for a predetermined time.
A drive torque control device for a hybrid vehicle characterized by the above. The drive torque control device for a hybrid vehicle according to any one of claims 8 to 9,
The start intention detection is that a target driving force before restriction corresponding to the accelerator opening equivalent driving force is equal to or greater than a driving force restriction upper limit threshold.
A drive torque control device for a hybrid vehicle characterized by the above. The first clutch capable of connecting / disconnecting the engine and the drive motor, the second clutch capable of connecting / disconnecting the drive motor and the drive wheel, and the brake braking force even when the brake pedal is released while the vehicle is stopped And a mechanism for releasing the brake braking force when the accelerator opening increases beyond the driving force threshold as a brake braking force release threshold that is set to be larger as the road gradient when the vehicle is stopped is larger. A vehicle driving torque control method comprising:
When it is detected that the accelerator opening is held below the driving force threshold value for releasing the brake braking force, and the target driving force is detected to be equal to or higher than the driving force limit start lower limit driving force for starting the driving force limit, Reducing the driving force to a predetermined driving force equal to or lower than the driving force limit start lower limit driving force;
A drive torque control method for a hybrid vehicle.

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