JP5919671B2 - Control device for hybrid vehicle - Google Patents

Description

  The present invention relates to a hybrid vehicle that includes an engine and a motor as a power source, has a first fastening element between the engine and the motor in a driving force transmission system, and has a second fastening element between the motor and the drive wheel. The present invention relates to a control device.

  In a hybrid vehicle having the first fastening element CL1 between the engine and the motor and having the second fastening element CL2 between the motor and the drive wheel, when the driving force transmission system load is large, the second fastening element CL2 is excessive. The second fastening element CL2 is protected by suppressing heat generation. To achieve this, when the driving force transmission system load is equal to or greater than a predetermined value, the first fastening element CL1 is released while the engine is operating, and the motor is set to a speed lower than the engine speed, and the second fastening element is set. One that selects a MWSC travel mode in which CL2 is slip-engaged is known (see, for example, Patent Document 1).

JP 2009-132195 A

  However, in the hybrid vehicle control apparatus, the estimated gradient is used as the driving force transmission system load, and the gradient estimation is performed using the front-rear G sensor value−the front wheel speed differential value (FR vehicle). In this way, since the driving force transmission system load determination is performed using the estimated gradient based on the front and rear G sensor values, the estimated gradient (= driving force transmission system load) can be correctly determined when entering the uphill gradient while turning. However, there is a problem that the transition to the MWSC travel mode for protecting the second fastening element CL2 is delayed.

  The present invention has been made paying attention to the above-described problem, and is a hybrid vehicle capable of shifting to the second fastening element protection traveling mode without delay by optimizing the load determination timing at a high load accompanied by a steering operation. An object is to provide a control device.

In order to achieve the above object, a control apparatus for a hybrid vehicle of the present invention includes an engine, a motor, a first fastening element, a second fastening element, a gradient estimating means , a second fastening element protection travel control means, And means for changing the threshold value.
The motor, you output a driving force of the vehicle.
The first fastening element is interposed between the engine and the motor and connects and disconnects the engine and the motor.
The second fastening element is interposed between the motor and the drive wheel to connect and disconnect the motor and the drive wheel.
The gradient estimation means estimates a road surface gradient based on the detection value of the longitudinal acceleration sensor and outputs it as an estimated gradient .
The second fastening element protection travel control means releases or slip-fastens the first fastening element while operating the engine at a predetermined rotational speed when the estimated gradient is equal to or greater than a threshold value, and causes the motor to rotate at the predetermined rotational speed. The second fastening element protection traveling mode in which the second fastening element is slip-fastened at a lower rotational speed is controlled.
The threshold value changing means lowers the threshold value for shifting to the second fastening element protection traveling mode when detecting that a steering operation has been performed.

Therefore, when the estimated gradient estimated based on the detection value of the longitudinal acceleration sensor is equal to or greater than the threshold value, the mode shifts to the second engagement element protection travel mode. The means is decreased when it is detected that the steering operation is performed.
That is, in the second fastening element protection traveling mode, since the motor is rotationally driven at a rotational speed lower than the engine rotational speed, the slip amount of the second fastening element can be reduced, and the heat generation amount of the second fastening element is reduced. Can be suppressed.
And when it detects that steering operation used as a factor which delays load determination was performed, the threshold of the estimated gradient which transfers to 2nd fastening element protection driving mode is reduced, and the timing of load determination becomes early. Therefore, the load determination timing is optimized at the time of starting on a turning uphill road, and the second engagement element protection travel mode can be shifted without delay, and the second engagement element can be protected from heat generation.
As a result, at the time of a high load accompanied by a steering operation, it is possible to shift to the second fastening element protection traveling mode without delay by optimizing the load determination timing.

1 is an overall system diagram illustrating a rear-wheel drive hybrid vehicle to which a control device according to a first embodiment is applied. 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 an example of the target drive torque map used for target drive torque calculation in the target drive torque calculating part of FIG. FIG. 3 is a diagram showing a relationship (a) between an estimated gradient and a mode map which are mode selection conditions in a mode selection unit in FIG. 2 and a relationship (b) of a CL2 protection traveling mode transition threshold value with respect to a steering angle (absolute value). It is a figure which shows an example of 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 3 pattern example of the MWSC corresponding | compatible mode map used for selection of a target mode in the mode selection part of FIG. 3 is a flowchart illustrating a flow of a travel mode transition control process executed by the integrated controller of the first embodiment. It is the schematic which shows the operating point of each actuator in WSC control. It is the schematic which shows the operating point of each actuator under MWSC control. It is the schematic which shows the operating point of each actuator in MWSC + CL1 slip control. It is a figure which shows the situation assumed by the control apparatus of Example 1 by the transfer determination of CL2 protection driving mode. It is a figure showing the relationship of the estimated gradient threshold value which transfers to CL2 protection driving mode with respect to a steering angle (absolute value) in the control apparatus of Example 2.

  Hereinafter, the best mode for realizing a control device for a hybrid vehicle of the present invention will be described based on Example 1 and Example 2 shown in the drawings.

First, the configuration will be described.
The configuration of the hybrid vehicle control device according to the first embodiment will be described by dividing it into "system configuration", "integrated controller control configuration", and "travel mode transition control configuration".

[System configuration]
FIG. 1 is an overall system diagram showing a rear-wheel drive hybrid vehicle to which the control device of the first embodiment is applied. Hereinafter, the system configuration (configuration of drive system and control system) will be described with reference to FIG.

  As shown in FIG. 1, the drive system of the hybrid vehicle includes an engine E, a first clutch CL1 (first engagement element), a motor generator MG (motor), a second clutch CL2 (second engagement element), It has an automatic transmission AT, a propeller shaft 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). FL is the front left wheel and FR is the front right wheel.

  The engine E is, for example, a gasoline engine, and the throttle valve opening and the like are controlled based on a control command from an engine controller 1 described later. The engine output shaft is provided with a flywheel FW.

  The first clutch CL1 is a clutch interposed between the engine E and the motor generator MG, and is generated by the first clutch hydraulic unit 6 based on a control command from the first clutch controller 5 described later. Fastening / release including slip fastening is controlled by the control hydraulic pressure.

  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 a three-phase AC generated by an inverter 3 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 “power running”), 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”). Note that 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, RR, and is produced by the second clutch hydraulic unit 8 based on a control command from the AT controller 7 described later. The controlled hydraulic pressure controls the fastening / release including slip fastening.

  The automatic transmission AT is a transmission that automatically switches a stepped gear ratio such as forward 7 speed, reverse 1 speed, etc. according to vehicle speed, accelerator opening, etc., and the second clutch CL2 is newly added as a dedicated clutch. Some of the frictional engagement elements among the plurality of frictional engagement elements that are engaged at each gear stage of the automatic transmission AT are not used. 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.

  The 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. The third travel mode is an abbreviated engine use slip travel mode (hereinafter referred to as “WSC travel mode”) in which the second clutch CL2 is slip-controlled while the first clutch CL1 is engaged and 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. When transitioning from the EV travel mode to the HEV travel mode, the first clutch CL1 is engaged and the engine is started using the torque of the motor generator MG.

  Also, when the driver adjusts the accelerator pedal and the accelerator hill hold is performed to maintain the vehicle stop state on an uphill road where the road surface gradient is greater than or equal to a predetermined value, the slip of the second clutch CL2 occurs when the WSC drive mode is set. Excessive amounts may continue. This is because the engine E cannot be made smaller than the idle speed. Therefore, as a CL2 protection control travel mode, a motor slip travel mode by CL1 release (hereinafter abbreviated as “MWSC travel mode”) and a motor slip travel mode by CL1 slip engagement (hereinafter abbreviated as “MWSC + CL1 slip control travel mode”). And). In the “MWSC travel mode”, the engine E and the motor generator MG are operated and the first clutch CL1 is released and the second clutch CL2 is slip-controlled to travel. In the “MWSC + CL1 slip control travel mode”, the first clutch CL1 and the second clutch CL2 are slip-controlled while the engine E and the motor generator MG are operated. Details will be described later.

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 assist travel mode”, the drive wheels are moved by using the engine E and the motor generator MG as power sources. The “running power generation mode” causes the motor generator MG to function as a generator at the same time as the drive wheels RR and RL are moved using the engine E as a power source. Further, during deceleration operation, the braking energy is regenerated and generated by the motor generator MG and used for charging the battery 4. Further, as a further mode, there is a power generation mode in which the motor generator MG is operated as a generator using the power of the engine E when the vehicle is stopped.

  As shown in FIG. 1, the hybrid vehicle control system includes an engine controller 1, a motor controller 2, an inverter 3, a battery 4, a first clutch controller 5, a first clutch hydraulic unit 6, and an AT controller 7. And a second clutch hydraulic unit 8, a brake controller 9, and an integrated controller 10. The engine controller 1, the motor controller 2, the first clutch controller 5, the AT controller 7, the brake controller 9, and the integrated controller 10 are connected via a CAN communication line 11 that can exchange information with each other. Has been.

  The engine controller 1 inputs the engine speed information from the engine speed sensor 12 and sets the engine operating point (Ne: engine speed, Te: engine torque) according to the target engine torque command from the integrated controller 10 or the like. A command to control is output to, for example, a throttle valve actuator (not shown). More detailed engine control contents will be described later. Information such as the engine speed Ne is supplied to the integrated controller 10 via the CAN communication line 11.

  The motor controller 2 receives information from the resolver 13 that detects the rotor rotational position of the motor generator MG, and according to a target motor generator torque command from the integrated controller 10, the motor operating point (Nm: motor A command for controlling the generator speed (Tm: motor generator torque) is output to the inverter 3. The motor controller 2 monitors the battery SOC indicating the state of charge of the battery 4. The battery SOC information is used as control information for the motor generator MG and supplied to the integrated controller 10 via the CAN communication line 11. Is done.

  The first clutch controller 5 inputs sensor information from the first clutch hydraulic pressure sensor 14 and the first clutch stroke sensor 15, and engages / releases the first clutch CL 1 according to the first clutch control command from the integrated controller 10. Is output to the first clutch hydraulic unit 6. Information on the first clutch stroke C1S is supplied to the integrated controller 10 via the CAN communication line 11.

  The AT controller 7 inputs sensor information from an accelerator opening sensor 16, a vehicle speed sensor 17, a second clutch hydraulic pressure sensor 18, and an inhibitor switch that outputs a signal corresponding to the position of a shift lever operated by the driver. In response to the second clutch control command from the controller 10, a command for controlling the engagement / release of the second clutch CL2 is output to the second clutch hydraulic unit 8 in the AT hydraulic control valve. Information on the accelerator opening APO, the vehicle speed VSP, and the inhibitor switch is supplied to the integrated controller 10 via the CAN communication line 11.

  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. For example, when the brake is depressed, the required braking force is obtained from the brake stroke BS. When the regenerative braking force is insufficient, the regenerative cooperative brake control is performed based on the regenerative cooperative control command from the integrated controller 10 so that the shortage is supplemented by the mechanical braking force (braking force by the friction brake).

  The integrated controller 10 manages the energy consumption of the entire vehicle and has a function for running the vehicle with the highest efficiency. The integrated controller 10 detects the motor rotation speed Nm, and the second clutch output rotation speed. A second clutch output speed sensor 22 for detecting N2out, a second clutch torque sensor 23 for detecting the second clutch transmission torque capacity TCL2, a steering angle sensor 24, and a CL2 temperature sensor for detecting the temperature of the second clutch CL2. 10a, information from the longitudinal acceleration sensor 10b for detecting longitudinal acceleration 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 based on the control command to the motor controller 2, and the first control command to the first clutch controller 5. Engagement / release control of the clutch CL1 and engagement / release control of the second clutch CL2 by a control command to the AT controller 7 are performed.

[Control configuration of integrated controller]
Next, the control configuration calculated by the integrated controller 10 of the first embodiment will be described using the block diagram shown in FIG. For example, this calculation is performed by the integrated controller 10 every control cycle of 10 msec.

  As shown in FIG. 2, the integrated controller 10 includes a target drive torque calculation unit 100, a mode selection unit 200, a target charge / discharge calculation unit 300, an operating point command unit 400, and a shift control unit 500. .

  The target drive torque calculator 100 calculates the target drive torque tFoO from the accelerator opening APO and the vehicle speed VSP using the target drive torque map shown in FIG.

  The mode selection unit 200 includes a road surface gradient estimation calculation unit 201 (a driving force transmission system load detection unit) that estimates a road surface gradient based on a detection value of the longitudinal acceleration sensor 10b. This road surface gradient estimation calculation unit 201 calculates the actual acceleration from the wheel speed acceleration average value of the wheel speed sensor 19, and the road surface gradient (= front / rear G sensor value−actual acceleration) from the difference between the calculation result and the front / rear G sensor value. ). And it has the mode map selection part 202 which selects either of the two mode maps mentioned later based on the estimated road surface gradient.

  As shown in FIG. 4, the mode map selection unit 202 switches to the MWSC compatible mode map (FIG. 6) when the estimated gradient is equal to or greater than the second threshold value g2 from the state where the normal mode map (FIG. 5) is selected. . On the other hand, when the estimated gradient becomes less than the first threshold value g1 (<g2) from the state where the MWSC compatible mode map (FIG. 6) is selected, the mode is switched to the normal mode map (FIG. 5). That is, as shown in FIG. 4 (a), hysteresis is provided for the estimated gradient to prevent control hunting during map switching. Then, the second threshold value g2 of the estimated gradient that shifts to the MWSC compatible mode map is changed and set according to the steering angle (absolute value) from the steering angle sensor 24, as shown in FIG. 4 (b).

  The normal mode map is selected when the estimated gradient is less than the first threshold value g1, and as shown in FIG. 5, the map has an EV driving mode, a WSC driving mode, and an HEV driving mode. The target mode is calculated from the opening APO and the vehicle speed VSP. However, even if the EV travel mode is selected, if the battery SOC is equal to or less than the predetermined value, the “HEV travel mode” is forcibly set as the target mode. In the normal mode map of FIG. 5, the HEV → WSC switching line has a rotational speed smaller than the idle rotational speed of the engine E when the automatic transmission AT is in the first speed in the region less than the predetermined accelerator opening APO1. It is set in a region lower than the lower limit vehicle speed VSP1. 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. When the battery SOC is low and the EV travel mode cannot be achieved, the WSC travel mode is selected even when starting. When the accelerator opening APO is large, it may be difficult to achieve the request with the engine torque corresponding to the engine speed near the idle speed and the torque of the motor generator MG. Here, more engine torque can be output if the engine speed increases. From this, if the engine speed is increased and a larger torque is output, even if the WSC drive mode is executed up to a vehicle speed higher than the lower limit vehicle speed VSP1, the WSC drive mode is changed to the HEV drive mode in a short time. be able to. This case corresponds to the WSC region extended to the lower limit vehicle speed VSP1 ′ shown in FIG.

The MWSC compatible mode map has a first schedule shown in FIG. 6 (a), a second schedule shown in FIG. 6 (b), and a third schedule shown in FIG. 6 (c).
As shown in FIG. 6A, the first schedule has a WSC travel mode, an MWSC travel mode, an MWSC + CL1 slip control travel mode, and an HEV travel mode in the map, and the accelerator opening APO and the vehicle speed. Calculate target mode from VSP.
As shown in FIG. 6 (b), the second schedule has a MWSC travel mode, a MWSC + CL1 slip control travel mode, and a HEV travel mode in the map. The target mode is determined from the accelerator opening APO and the vehicle speed VSP. Is calculated.
As shown in FIG. 6 (c), the third schedule has a WSC drive mode, an EV drive mode, an MWSC + CL1 slip control drive mode, and an HEV drive mode in the map, and the accelerator opening APO and the vehicle speed. Calculate target mode from VSP.
These first to third schedules may be selected according to conditions such as the motor generator MG, the first clutch CL1, the second clutch CL2, etc. for each vehicle type, or at least two of the first to third schedules in one hybrid vehicle. Two schedules may be used properly.

  The target charge / discharge calculation unit 300 calculates a target charge / discharge power tP from the battery SOC using a target charge / discharge amount map.

  In the operating point command unit 400, from the accelerator opening APO, the target drive torque tFoO, the target mode, the vehicle speed VSP, and the target charging / discharging power tP, the target engine torque is a transient target engine torque. The target motor 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. Further, the operating point command unit 400 is provided with an engine start control unit that starts the engine E when the EV travel mode is changed to the HEV travel mode.

  The shift control unit 500 drives and controls a 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 a predetermined shift schedule. In the shift map, the target shift speed is set in advance based on the vehicle speed VSP and the accelerator opening APO.

[Running mode transition control configuration]
FIG. 7 is a flowchart illustrating the flow of the travel mode transition control process executed by the integrated controller 10 according to the first embodiment. Hereinafter, each step representing the travel mode transition control configuration will be described with reference to FIG.

  In step S1, it is determined whether or not the normal mode map is selected. If YES (selection of normal mode map), the process proceeds to step S2, and if NO (selection of MWSC compatible mode map), the process proceeds to step S11.

In step S2, following the determination that the normal mode map is selected in step S1, it is determined whether or not the WSC travel mode is selected. If YES (selection of WSC travel mode), the process proceeds to step S3. If NO (selection other than WSC travel mode), the process proceeds to step S20 to execute control processing based on the normal mode map.
Here, there is no problem when the initial state is the selected state of the WSC drive mode, but when the initial state is the selected state of the EV drive mode, it waits until the mode transition from the EV drive mode to the WSC drive mode is performed by the accelerator depression operation. (See FIG. 5).

In step S3, following the determination that the WSC traveling mode is selected in step S2, it is determined whether the CL2 temperature from the CL2 temperature sensor 10a is equal to or higher than a predetermined value. If YES (CL2 temperature ≧ predetermined value), the process proceeds to step S4. If NO (CL2 temperature <predetermined value), the process proceeds to step S20 to execute control processing based on the normal mode map.
Here, the predetermined value needs to shift to the CL2 protection traveling mode (MWSC traveling mode and MWSC + CL1 slip control traveling mode), reduce the thermal load caused by slip engagement applied to the second clutch CL2, and protect the second clutch CL2. It is set to a certain CL2 temperature.

In step S4, following the determination that CL2 temperature ≧ predetermined value in step S3, the second threshold value g2 of the estimated gradient for shifting to the MWSC compatible mode map is changed and set by the steering angle (absolute value), and step S5 Proceed to
Here, as shown in FIG. 4B, the second threshold value g2 is changed when the steering angle (absolute value) from the steering angle sensor 24 is equal to or less than the determination threshold value (steering determination threshold value) for steering failure. The value is set based on the uphill road, and is decreased by a certain amount of decrease in a region exceeding the steering determination threshold.

  In step S5, following the change setting of the second threshold value g2 by the steering operation in step S4, it is determined whether or not the estimated gradient is larger than the second threshold value g2 after the change setting. If YES (estimated gradient> g2), the process proceeds to step S6, and if NO (estimated gradient ≦ g2), the process proceeds to step S20 to execute control processing based on the normal mode map.

  In step S6, following the YES determination in step S5, the normal mode map is switched to the MWSC compatible mode map, and the process proceeds to step S7.

  In step S7, following the mode map switching in step S6 or NO determination in step S16, it is determined whether or not the operating point determined by the current accelerator opening APO and vehicle speed VSP is within the MWSC driving mode region. To do. If YES (in the MWSC travel mode area), the process proceeds to step S8. If NO (outside the MWSC travel mode), the process proceeds to step S11.

In step S8, following the YES determination in step S7, it is determined whether or not the battery SOC is greater than a predetermined value A. When YES (battery SOC> A), the process proceeds to step S9, and when NO (battery SOC ≦ A), the process proceeds to step S14.
Here, the predetermined value A is a threshold value for determining whether or not the driving force can be secured only by the motor generator MG. When the battery SOC is larger than the predetermined value A, the driving force can be secured only by the motor generator MG. When the battery SOC is lower than the predetermined value A, the battery 4 needs to be charged, so the selection of the MWSC traveling mode is prohibited. To do.

In step S9, following the YES determination in step S8, it is determined whether or not the transmission torque capacity TCL2 of the second clutch CL2 is less than a predetermined value B. If YES (TCL2 <B), the process proceeds to step S10, and if NO (TCL2 ≧ B), the process proceeds to step S14.
Here, the predetermined value B is a predetermined value indicating that an excessive current does not flow through the motor generator MG. Since motor generator MG is controlled in rotational speed, the torque generated in motor generator MG is equal to or greater than the driving force transmission system load acting on motor generator MG.
In other words, since the motor generator MG is controlled in rotational speed so that the second clutch CL2 is in the slip state, a torque larger than the second clutch transmission torque capacity TCL2 is generated in the motor generator MG. Therefore, when the transmission torque capacity TCL2 of the second clutch CL2 is excessive, the current flowing through the motor generator MG becomes excessive, and the durability of the switching element and the like deteriorates. In order to avoid this state, selection of the MWSC travel mode is prohibited when the value is equal to or greater than the predetermined value B.

In step S10, following the YES determination in step S9, MWSC control processing is executed, and the process proceeds to return.
Specifically, in the MWSC control process, the first clutch CL1 is released while the engine is operating, the engine E is set to feedback control so as to become the idle speed, and the motor generator MG is set to the output side speed Ncl2out of the second clutch CL2. The feedback control is performed to obtain a target rotational speed obtained by adding the predetermined rotational speed β to (a value lower than the idle rotational speed), and the second clutch CL2 is set to a transmission torque capacity corresponding to the target driving torque. Since the MWSC travel mode is not set in the normal mode map, the MWSC control processing in step S10 includes mode transition processing from the WSC travel mode and the idle power generation mode.

  In step S11, following the NO determination in step S7, it is determined whether or not the operating point determined by the current accelerator opening APO and vehicle speed VSP is within the MWSC + CL1 slip control travel mode region. If YES (in the MWSC + CL1 slip control travel mode region), the process proceeds to step S12. If NO (out of the MWSC + CL1 slip control travel mode), the process proceeds to step S13.

In step S12, following the YES determination in step S11, MWSC + CL1 slip control processing is executed, and the process proceeds to return.
Specifically, in the MWSC + CL1 slip control process, the engine CL is slip-engaged with the target CL1 torque of the first clutch CL1 as the required torque while the engine is operating, the engine E is set to feedback control so as to become the idle speed, and the motor generator MG is Feedback control is performed to obtain a target rotational speed obtained by adding a predetermined rotational speed β ′ to the output rotational speed Ncl2out of the two clutch CL2 (however, a value lower than the idle rotational speed), and the second clutch CL2 is transmitted according to the target driving torque The feedback control for torque capacity is used. The target CL1 torque is, for example, (target drive torque−α) when requesting reduction of motor torque, (target drive torque) when requesting zero motor torque, and (target drive torque + power generation torque) when requesting power generation. To do. Further, the predetermined rotational speed β ′ (= CL2 slip amount) is set to a lower rotational speed as the CL2 temperature is higher, for example.

  In step S13, following the NO determination in step S11, it is determined whether or not the operating point determined by the current accelerator opening APO and vehicle speed VSP is within the WSC travel mode region. If YES (in the WSC drive mode area), the process proceeds to step S14, and if NO (out of the WSC drive mode area), it is determined that the vehicle is in the HEV drive mode area, and the process proceeds to step S15.

In step S14, following the YES determination in step S13, WSC control processing is executed, and the process proceeds to return.
Specifically, in the WSC control process, the first clutch CL1 is completely engaged, the engine E is set to feedforward control in accordance with the target torque, the motor generator MG is set to feedback control for idling speed, and the second clutch CL2 is set to the target. It is set as the feedback control which makes the transmission torque capacity according to a driving torque. In the case of the MWSC compatible mode map in which the EV travel mode is not set, the WSC control process in step S14 includes a mode transition process from the EV travel mode.

In step S15, following the NO determination in step S13, HEV control processing is executed, and the process proceeds to return.
Specifically, in the HEV control process, the first clutch CL1 is completely engaged, the engine E and the motor generator MG are feedforward controlled so as to have a torque corresponding to the target drive torque, and the second clutch CL2 is completely engaged. In the case of the MWSC compatible mode map in which the EV travel mode is not set, the HEV control process in step S12 includes a mode transition process from the EV travel mode.

  In step S16, following the determination of NO in step S1, it is determined whether the estimated gradient is less than the first threshold value g1. If YES (estimated gradient <g1), the process proceeds to step S17. If NO (estimated gradient ≧ g1), the process proceeds to step S7 and the control by the MWSC compatible mode map is continued.

  In step S17, following the YES determination in step S16, the mode map is switched from the MWSC compatible mode map to step S18.

In step S18, following the map switching in step S17, it is determined whether or not the travel mode has been changed along with the map switching. If YES (travel mode is changed), the process proceeds to step S19, and if NO (travel mode is not changed), the process proceeds to step S20.
When switching from the MWSC compatible mode map to the normal mode map, a transition from the MWSC travel mode to the WSC travel mode, a transition from the WSC travel mode to the EV travel mode, a transition from the HEV travel mode to the EV travel mode, etc. occur. Because you get.

In step S19, following the YES determination in step S18, a travel mode change process is executed, and the process proceeds to step S20.
Specifically, for example, at the time of transition from the MWSC travel mode to the WSC travel mode, the target rotational speed of the motor generator MG is changed to the idle rotational speed, and the first clutch CL1 is engaged at the synchronized stage. Then, the engine control is switched from the idle speed feedback control to the target engine torque feedforward control.

  In step S20, following the NO determination in step S2, S3, S5, the NO determination in step S18, or the travel mode change process in step S19, the control process based on the normal mode map is executed, and the process returns. move on.

Next, the operation will be described.
The effects of the hybrid vehicle control device of the first embodiment are as follows: “Comparison of WSC control / MWSC control / MWSC + CL1 slip control”, “WSC drive mode action”, “MWSC drive mode action”, “MWSC + CL1 slip control drive mode action”, The description will be divided into “the change setting operation of the second threshold value g2 of the estimated gradient”.

[Comparison of WSC control / MWSC control / MWSC + CL1 slip control]
8 is an operating point of each actuator during WSC control, FIG. 9 is an operating point of each actuator during MWSC control, and FIG. 10 is a schematic diagram showing an operating point of each actuator during MWSC + CL1 slip control. Hereinafter, the WSC control, the MWSC control, and the MWSC + CL1 slip control will be described based on FIGS.

  As shown in FIG. 8, “WSC control” fully engages the first clutch CL1, sets the engine E to feedforward control according to the target engine torque, and sets the motor generator MG to feedback control at an idle speed. The second clutch CL2 is controlled to be slip-engaged with feedback control using a transmission torque capacity corresponding to the target drive torque.

  As shown in FIG. 9, “MWSC control” performs feedback control so that the first clutch CL <b> 1 is released while the engine is operating, and the engine E is at the idling speed. Then, feedback control is performed in which the motor generator MG is set to a target rotational speed obtained by adding the predetermined rotational speed β to the output-side rotational speed Ncl2out of the second clutch CL2 (however, a value lower than the idle rotational speed). The second clutch CL2 is controlled to be slip-engaged with feedback control using a transmission torque capacity corresponding to the target drive torque.

  As shown in FIG. 10, in “MWSC + CL1 slip control”, the engine CL is slip-engaged with the target CL1 torque of the first clutch CL1 set as (target drive torque−α) while the engine is operating, so that the engine E becomes the idle speed. Use feedback control. Then, feedback control is performed in which the motor generator MG is set to a target rotational speed (a value lower than the idle rotational speed) obtained by adding the predetermined rotational speed β ′ to the output-side rotational speed Ncl2out of the second clutch CL2. The second clutch CL2 is controlled to be slip-engaged with feedback control using a transmission torque capacity corresponding to the target drive torque. The predetermined rotational speed β ′ (= CL2 slip amount) is set to a lower rotational speed as the heat generation amount of the second clutch CL2 is higher.

  The WSC travel mode based on “WSC control” is characterized in that the engine E is maintained in an operating state and that the first clutch CL1 is completely engaged. In the WSC travel mode, the difference between the drive wheel speed and the engine speed can be absorbed by the slip of the second clutch CL2. Further, since the target drive torque change can be dealt with by the torque capacity change of the second clutch CL2, the responsiveness to the target drive torque change is high. Then, the second clutch CL2 is slip-controlled as a transmission torque capacity corresponding to the target driving torque, and travels using the driving force of the engine E and / or the motor generator MG.

  The MWSC travel mode by “MWSC control” is characterized in that the first clutch CL1 that is completely engaged in the WSC travel mode is released. In the MWSC travel mode, the slip amount can be controlled by controlling the rotational speed of the motor generator MG without being constrained by the idle speed of the engine E. Therefore, the slip amount of the second clutch CL2 (= β) compared to the WSC travel mode Can be reduced. Then, the second clutch CL2 is slip-controlled as a transmission torque capacity corresponding to the target driving torque, and travels using the driving force of the motor generator MG.

  The MWSC + CL1 slip control travel mode based on “MWSC + CL1 slip control” is characterized in that the first clutch CL1 released in the MWSC travel mode is slip-engaged. In the MWSC + CL1 slip control travel mode, the slip amount (= β ′) of the second clutch CL2 can be reduced as in the MWSC travel mode. Furthermore, the motor torque of the motor generator MG can be reduced by adding the transmission torque capacity of the first clutch CL1 as the drive torque. Then, the second clutch CL2 is slip-controlled as a transmission torque capacity corresponding to the target driving torque, and travels using the driving force of the engine E and the motor generator MG. Alternatively, the vehicle travels or generates electricity using the driving force of the engine E.

[WSC mode operation]
The reason for setting the WSC travel mode area will be described. In the hybrid vehicle of the first embodiment, there is no element that absorbs the difference in rotational speed unlike the torque converter. Therefore, when the first clutch CL1 and the second clutch CL2 are completely engaged, the vehicle speed is determined according to the rotational speed of the engine E. End up. The engine E has a lower limit value due to the idling engine speed for maintaining the self-sustaining rotation, and this idling engine speed becomes higher when the engine is idling up due to warm-up operation of the engine or the like. In addition, when the target drive torque is high, there may be a case where the HEV traveling mode cannot be quickly changed.

  On the other hand, in the EV travel mode, since the first clutch CL1 is released, there is no limit associated with the lower limit value due to the engine speed. However, in the case where it is difficult to travel in the EV travel mode due to restrictions based on the battery SOC, or in a region where the target drive torque cannot be achieved only by the motor generator MG, there is no means other than generating stable torque by the engine E.

  Therefore, in a vehicle speed range lower than the vehicle speed corresponding to the above lower limit value, and when it is difficult to travel in the EV travel mode, or in a region where the target drive torque cannot be achieved only by the motor generator MG, the engine speed is set to a predetermined value. While maintaining the lower limit rotational speed, the second clutch CL2 is slip-controlled, and the WSC traveling mode for traveling using the engine torque is selected.

  In the first embodiment, when the normal mode map is selected and the flow to step S20 in the flowchart of FIG. 7 is repeated, the current accelerator opening APO and the current accelerator opening APO are displayed on the normal mode map (FIG. 5). When the operating point based on the vehicle speed VSP is within the WSC travel mode area, the WSC travel mode is selected.

Therefore, when the WSC traveling mode is selected when starting on a flat road, the following advantages can be obtained.
(a) The second clutch CL2 serves as a rotational difference absorbing element between the drive wheel rotational speed and the engine rotational speed, and the rotational difference can be absorbed by the slip of the second clutch CL2.
(b) Since the second clutch CL2 has a transmission torque capacity corresponding to the target drive torque, the drive torque requested by the driver can be transmitted to the drive wheels to start the vehicle.
(c) Because it is possible to respond to changes in the target driving torque due to changes in the accelerator opening APO and changes in the vehicle speed VSP by changing the transmission torque capacity of the second clutch CL2, without waiting for the driving force change due to the engine E, High responsiveness to changes in target drive torque.

[MWSC travel mode action]
The reason why the MWSC travel mode area is set will be described. When the estimated gradient of the running road surface is larger than the predetermined gradient (g1 or g2), for example, if the vehicle is maintained in a stopped state or a slow start state without operating the brake pedal, a large driving force is obtained compared to a flat road. Required. This is because it is necessary to counter the gradient load applied to the host vehicle.

  From the viewpoint of avoiding heat generation due to the slip of the second clutch CL2, it is also conceivable to select the EV travel mode when the battery SOC has a margin. At this time, it is necessary to start the engine when transitioning from the EV travel mode region to the WSC travel mode region, and the motor generator MG outputs the drive torque while securing the engine start torque, so the drive torque upper limit value is unnecessary. It is narrowed to.

  Moreover, when only the torque is output to the motor generator MG in the EV travel mode and the motor generator MG stops or rotates at a very low speed, a lock current flows through the switching element of the inverter (a phenomenon in which the current continues to flow through one element), There is a risk of lowering durability.

  Further, in a region lower than the lower limit vehicle speed VSP1 corresponding to the idle speed of the engine E at the first speed (region below VSP2 in FIG. 6), the engine E itself cannot be decreased below the idle speed. At this time, if the WSC travel mode is selected, the slip amount of the second clutch CL2 increases, which may affect the durability of the second clutch CL2.

  In particular, since a large driving force is required on an uphill road compared to a flat road, the transmission torque capacity required for the second clutch CL2 is high, and a high torque and high slip amount state is continued. This tends to cause a decrease in durability of the second clutch CL2. In addition, since the vehicle speed rises slowly, it takes time until the transition to the HEV travel mode, and there is a risk of further generating heat.

  Therefore, the first clutch CL1 is released while the engine E is operated, and the transmission torque capacity of the second clutch CL2 is controlled to the driver's target drive torque, while the rotation speed of the motor generator MG is the same as that of the second clutch CL2. An MWSC driving mode was set in which feedback control is performed to a target rotational speed that is higher than the output rotational speed by a predetermined rotational speed.

  In other words, the second clutch CL2 is slip-controlled while the rotational state of the motor generator MG is set to a rotational speed lower than the idle rotational speed of the engine. At the same time, the engine E switches to feedback control in which the idling speed is set as the target speed. In the WSC travel mode, the engine speed was maintained by the rotational speed feedback control of the motor generator MG. On the other hand, when the first clutch CL1 is released, the engine speed cannot be controlled to the idle speed by the motor generator MG. Therefore, engine speed feedback control is performed by the engine E itself.

  In the first embodiment, when the MWSC-compatible mode map is selected and the flow of proceeding to step S10 in the flowchart of FIG. 7 is repeated, the current accelerator opening degree is displayed on the MWSC-compatible mode map (FIG. 6). When the operating point based on the APO and the vehicle speed VSP is within the MWSC travel mode area, the MWSC travel mode is selected.

Therefore, the following advantages can be obtained when the MWSC travel mode is selected when starting up a slope.
(a) Since the engine E is in an operating state, it is not necessary to leave the driving torque for starting the engine in the motor generator MG, and the driving torque upper limit value of the motor generator MG can be increased. Specifically, when viewed on the target drive torque axis, it is possible to cope with a target drive torque higher than that in the EV travel mode region.
(b) The durability of the switching element and the like can be improved by ensuring the rotation state of the motor generator MG.
(c) Since the motor generator MG is rotated at a lower rotational speed than the idle rotational speed, the slip amount of the second clutch CL2 can be reduced, and the durability of the second clutch CL2 can be improved. (CL2 protection control).

[MWSC + CL1 slip control travel mode action]
The reason why the MWSC + CL1 slip control travel mode area is set will be described. In the MWSC travel mode, the motor generator MG is used to reduce the slip rotation speed of the second clutch CL2. For this reason, the MWSC travel mode cannot be applied when there is an output limitation of the motor generator MG or an output limitation of the battery 4.

  Therefore, a traveling mode is assumed in which, for example, the second clutch CL2 is completely engaged and slip control at the time of starting is performed by the first clutch CL1 at a time when the MWSC traveling mode cannot be applied. In this travel mode, the slip amount of the first clutch CL1 increases, which has an effect on the durability of the first clutch CL1. Further, when the second clutch CL2 is completely engaged, there is a step when the second clutch CL2 is shifted to slip again. Furthermore, it is necessary to balance the first clutch torque when performing power generation.

  Therefore, when the motor torque of motor generator MG cannot ensure the driver's required drive torque (= target drive torque), the MWSC travel mode cannot be maintained. Therefore, the WSC driving mode is forced to be selected, and the slip rotation speed of the second clutch CL2 increases (when the first clutch CL1 is fully engaged) when starting on an uphill road, and the durability of the second clutch CL2 is increased. Has an effect.

  In other words, when the motor torque cannot be equivalent to the driver's required drive torque (= target drive torque) and the MWSC drive mode cannot be maintained, a drive mode that replaces the MWSC drive mode is necessary. At this time, MWSC + CL1 slip Select the controlled travel mode.

  In the first embodiment, when the MWSC compatible mode map is selected, and the flow of proceeding to step S12 in the flowchart of FIG. 7 is repeated, the current accelerator opening degree is displayed on the MWSC compatible mode map (FIG. 6). When the operating point based on APO and vehicle speed VSP is within the MWSC + CL1 slip control travel mode region, the MWSC + CL1 slip control travel mode is selected.

  Next, the reason why the motor torque is reduced by selecting the MWSC + CL1 slip control travel mode will be described (see FIGS. 8 to 10).

The equation of motion around the engine axis is
Teng−Tcl1 ＝ Ieng ・ dωeng (1)
The equation of motion around the motor shaft is
Tmg + Tcl1-Tcl2 = Img · dωmg (2)
It is expressed. However,
Teng: Engine torque Tmg: Motor torque Tcl1: CL1 torque capacity Tcl2: CL2 torque capacity Ieng: Engine inertia Img: Motor inertia
dωeng: Engine rotation angular acceleration
dωmg: Motor rotation angular acceleration.

In the MWSC mode, Tcl1 = 0, so the above equation (1) is
Teng ＝ Ieng ・ dωeng… (1-1)
And the above equation (2) is
Tmg−Tcl2 = Img · dωmg (2-1)
It becomes. Therefore, when the MWSC mode is selected, the motor torque Tmg that can counter the CL2 torque capacity Tcl2 is necessary, as is apparent from the equation (2-1).

  On the other hand, in the MWSC + CL1 slip control travel mode, Tcl1> 0, so that the CL2 torque capacity Tcl2 is countered by the torque obtained by adding the motor torque Tmg and the CL1 torque capacity Tcl1 as apparent from the above equation (2). To do. Therefore, the motor torque Tmg can be reduced by the CL1 torque capacity Tcl1 (> 0).

Therefore, when the MWSC + CL1 slip control travel mode is selected when starting on an uphill road, the following merits can be obtained.
(a) When the MWSC + CL1 slip control travel mode is selected, the first clutch CL1 slips, so that the motor torque of the motor generator MG is reduced. As a result, it is possible to improve the durability of motor generator MG and reduce power consumption.
(b) By selecting the MWSC + CL1 slip control travel mode at the accelerator opening upper limit APO1 or higher at which the MWSC travel mode is selected, the selection of the MWSC travel mode is maintained while the motor generator MG can be used. As a result, the load on the first clutch CL1 can be reduced by selecting the MWSC + CL1 slip control travel mode over a long period of time.
(c) The slip amount β ′ of the second clutch CL2 in the MWSC + CL1 slip control travel mode is determined by the CL2 temperature at the time of mode transition from the MWSC travel mode. As a result, after the mode transition to the MWSC + CL1 slip control travel mode, the thermal load on the second clutch CL2 can be reduced (CL2 protection control) in the same manner as when the MWSC travel mode is selected.

[Change setting action of second threshold value g2 of estimated gradient]
First, the road surface gradient is estimated by the formula of (front / rear G sensor value−actual acceleration), and a case where a constant value is given as the second threshold value g2 of the estimated gradient regardless of the steering operation is a comparative example.

  In the case of this comparative example, for example, as shown in FIG. 11, when assuming a situation where the flat road and the slope road are orthogonal and the vehicle enters the slope road from the flat road, the front and rear G sensors corresponding to the road surface slope are provided. No value is output and correct gradient judgment (high load judgment of driving force transmission system) cannot be performed. This is because the vehicle acceleration generated by turning uphill traveling is divided into a longitudinal acceleration component and a lateral acceleration component, and the longitudinal acceleration component decreases as the lateral acceleration component increases. That is, when only the longitudinal G sensor value is used during turning uphill with steering operation, the longitudinal acceleration component is detected, and the road surface gradient estimated from the longitudinal acceleration component is smaller than the actual gradient. Therefore, in order to obtain a highly accurate estimated gradient when turning uphill, it is necessary to add left and right G sensors to the front and rear G sensors. In this case, the addition of the sensors causes an increase in cost.

  On the other hand, the transition of the MWSC compatible mode map for selecting the CL2 protection travel mode (MWSC travel mode, MWSC + CL1 slip control travel mode) is determined by the estimated gradient ≧ second threshold value g2. Therefore, as shown by the dotted line characteristics in FIG. 4 (b), in the case of the comparative example in which the second threshold value g2 is given as a constant value, the estimated gradient becomes smaller than the actual gradient when turning uphill. The transition to the map is delayed. As a result, the WSC traveling mode in which the heat generation of the second clutch CL2 proceeds due to a large slip amount is continued, and the life of the second clutch CL2 is shortened.

  In contrast, in the first embodiment, when all of the normal mode map selection condition, the WSC travel mode selection condition, and the CL2 temperature condition are satisfied, the process proceeds from step S1 to step S2 to step S3 to step S4 in the flowchart of FIG. In step S4, the second threshold value g2 of the estimated gradient that shifts to the MWSC compatible mode map is changed and set to a value that is decreased when it is detected that the steering operation is performed based on the steering angle (absolute value). The

Accordingly, as shown in FIG. 11, when turning uphill that enters from a flat road to a slope road, the second slope g2 is changed to a value that is reduced, so that the estimated slope is smaller than the actual slope. In the next step S5, it is determined that the estimated gradient> g2, and the process proceeds to step S6 to switch from the normal mode map to the MWSC compatible mode map.
In this manner, the load determination timing is advanced when turning uphill, and it is possible to quickly shift to the CL2 protection traveling mode (MWSC traveling mode, MWSC + CL1 slip control traveling mode) that reduces the thermal load of the second clutch CL2.

Next, the effect will be described.
In the hybrid vehicle control device of the first embodiment, the following effects can be obtained.

(1) Engine E,
A motor (motor generator MG) for outputting the driving force of the vehicle and starting the engine E;
A first engagement element (first clutch CL1) interposed between the engine E and the motor (motor generator MG) and connecting / disconnecting the engine E and the motor (motor generator MG);
A second member that is interposed between the motor (motor generator MG) and drive wheels (left and right rear wheels RL, RR) to connect and disconnect the motor (motor generator MG) and drive wheels (left and right rear wheels RL, RR). A fastening element (second clutch CL2);
Driving force transmission system load detecting means (road surface gradient estimation calculating unit 201) for detecting or estimating the driving force transmission system load;
When the driving force transmission system load is equal to or greater than a threshold value, the first engagement element (first clutch CL1) is released or slip-engaged while the engine E is operated at a predetermined rotational speed, and the motor (motor generator MG) is operated. A second engagement element that is controlled to a second engagement element protection traveling mode (MWSC traveling mode, MWSC + CL1 slip control traveling mode) in which the second engagement element (second clutch CL2) is slip-engaged at a rotational speed lower than the predetermined rotational speed. Protective travel control means (steps S10 and S12 in FIG. 7);
Threshold changing means for reducing the threshold value for shifting to the second engagement element protection traveling mode (MWSC traveling mode, MWSC + CL1 slip control traveling mode) when it is detected that a steering operation has been performed (step S4 in FIG. 7) When,
Is provided.
For this reason, it is possible to shift to the second engagement element protection travel mode (MWSC travel mode, MWSC + CL1 slip control travel mode) without delay by optimizing the load determination timing at the time of a high load accompanied by a steering operation.

(2) The driving force transmission system load detection means includes a road surface gradient estimation calculation unit 201 that calculates an estimated gradient based on the longitudinal acceleration sensor value from the longitudinal acceleration sensor 10b.
The threshold value changing means (step S4 in FIG. 7) determines the threshold value (second threshold value g2) of the estimated gradient for shifting to the second engagement element protection travel mode (MWSC travel mode, MWSC + CL1 slip control travel mode) by steering operation. Is reduced when it is detected that has been done.
For this reason, in addition to the effect of (1), the gradient estimation error based on the longitudinal acceleration sensor value is reduced by changing the threshold value of the estimated gradient (second threshold value g2), and the load is determined accurately using the estimated gradient. It can be performed.

(3) An engine-use slip traveling mode (WSC traveling) in which the first engagement element (first clutch CL1) is engaged while the engine E is operated, and the second engagement element (second clutch CL2) is slip-engaged. Engine use slip travel control means (step S14 in FIG. 7) for controlling
The driving force transmission system load detecting means is means for detecting or estimating a thermal load of the road surface gradient and the second engagement element (second clutch CL2),
The threshold changing means (step S4 in FIG. 7), when the initial state is a selected state of the engine use slip running mode (WSC running mode) (YES in step S2), the second engagement element (second clutch CL2). ) Is equal to or greater than the predetermined load (YES in step S3), the road surface gradient threshold value (second threshold value) to shift to the second engagement element protection travel mode (MWSC travel mode, MWSC + CL1 slip control travel mode) g2) is decreased when it is detected that the steering operation is performed.
For this reason, in addition to the effect of (2), when the initial state is the engine using slip traveling mode (WSC traveling mode), the thermal load of the second engagement element (second clutch CL2) is applied to the driving force transmission system load. Thus, when the protection of the second engagement element (second clutch CL2) is necessary, it is possible to shift to the second engagement element protection traveling mode (MWSC traveling mode, MWSC + CL1 slip control traveling mode) at an early timing.

(4) Motor use travel mode (EV travel mode) in which the first engagement element (first clutch CL1) is released and the second engagement element (second clutch CL2) is engaged with the engine E stopped. Motor use travel control means to control to,
In an engine use slip traveling mode (WSC traveling mode) in which the first engagement element (first clutch CL1) is engaged while the engine E is operated, and the second engagement element (second clutch CL2) is slip-engaged. Engine-use slip running control means (step S14 in FIG. 7) for controlling,
The driving force transmission system load detecting means is means for detecting or estimating a thermal load of the road surface gradient and the second engagement element (second clutch CL2),
When the initial state is a selection state of the motor use travel mode (EV travel mode), the threshold value changing means (step S4 in FIG. 7) shifts to the engine use slip travel mode (WSC travel mode) by an accelerator operation. (YES in step S2), when the thermal load of the second engagement element (second clutch CL2) exceeds a predetermined load (YES in step S3), the second engagement element protection traveling mode (MWSC traveling mode, MWSC + CL1) The threshold value (second threshold value g2) of the road surface gradient that shifts to the slip control travel mode) is decreased when it is detected that the steering operation is performed.
For this reason, in addition to the effect of (2), when the initial state is the motor use travel mode (EV travel mode), waiting for the transition to the engine use slip travel mode (WSC travel mode), By applying the thermal load of 2 clutch CL2) to the driving force transmission system load, the second engagement element protection travel mode (MWSC travel mode, MWSC + CL1) is required at an early timing when the second engagement element (second clutch CL2) needs to be protected. It is possible to shift to the slip control travel mode.

(5) The threshold value changing means (step S4 in FIG. 7) sets the road surface gradient threshold value (second threshold value g2) for shifting to the second engagement element protection travel mode (MWSC travel mode, MWSC + CL1 slip control travel mode). Then, in the region where the absolute value of the steering angle from the steering angle sensor 24 exceeds the steering determination threshold value, it is reduced by a certain reduction width (FIG. 4 (b)).
For this reason, in addition to the effects of (2) to (4), when the steering determination is made, the shift to the second engagement element protection traveling mode (MWSC traveling mode, MWSC + CL1 slip control traveling mode) is performed early regardless of the steering amount. be able to.

  The second embodiment is an example in which the change setting of the threshold value of the road surface gradient during the steering operation is different from the first embodiment.

  Explaining the configuration, the configuration of the second embodiment is the same as that of the first embodiment except for step S4 in FIG. Hereinafter, step S4 in the second embodiment will be described.

In step S4, following the determination that CL2 temperature ≧ predetermined value in step S3, the second threshold value g2 of the estimated gradient for shifting to the MWSC compatible mode map is changed and set by the steering angle (absolute value), and step S5 Proceed to
Here, as shown in FIG. 12, when the steering angle (absolute value) from the steering angle sensor 24 is equal to or smaller than the determination threshold value (steering determination threshold value) for steering failure, the second threshold value g2 is changed. The value is set based on this value, and in a region exceeding the steering determination threshold value, the larger the steering angle (absolute value), the smaller the variable reduction width.

Next, the operation will be described. In the case of the second embodiment, in the region exceeding the steering determination threshold value, the larger the steering angle (absolute value), the lower it is decreased by a larger variable decrease width. The calculation error of the estimated gradient that occurs in 201 is cancelled. In other words, the estimated gradient is calculated based on the longitudinal acceleration sensor value from the longitudinal acceleration sensor 10b, and the second threshold value g2 is changed and set in accordance with the fact that the calculation error with the actual gradient becomes larger as the left and right G are generated by turning. It depends on what you are doing.
Since other operations are the same as those of the first embodiment, description thereof is omitted.

Next, the effect will be described.
In the hybrid vehicle control apparatus of the second embodiment, the following effects can be obtained in addition to the effects (2) to (4) of the first embodiment.

(6) The threshold value changing means (step S4 in FIG. 7) sets the threshold value (second threshold value g2) of the road surface gradient to be shifted to the second fastening element protection travel mode (MWSC travel mode, MWSC + CL1 slip control travel mode). In the region where the steering angle absolute value from the steering angle sensor 24 exceeds the steering determination threshold, the larger the steering angle absolute value, the lower the value by a larger variable reduction width (FIG. 12).
For this reason, when the steering determination is made, it is possible to shift to the second fastening element protection travel mode (MWSC travel mode, MWSC + CL1 slip control travel mode) at an appropriate timing according to the steering amount.

  As mentioned above, although the control apparatus of the hybrid vehicle of this invention has been demonstrated based on Example 1 and Example 2, it is not restricted to these Examples about a concrete structure, Each claim of a claim Design changes and additions are permitted without departing from the spirit of the invention according to the paragraph.

  In the first and second embodiments, the example in which the road surface gradient estimation calculation unit 201 that estimates the road surface gradient is used as the driving force transmission system load detection unit has been described. However, the driving force transmission system load detection means may detect the presence or absence of vehicle traction or the like, or may detect an on-vehicle load. This is because when the driving force transmission system load is large as described above, the increase in the vehicle speed is slow and the second clutch CL2 is likely to generate heat. Further, as the driving force transmission system load detection means, the detected temperature of the second clutch CL2, the estimated temperature, or the estimated calorific value may be used. For example, when the estimated heat generation amount of the second clutch CL2 is used as the driving force transmission system load, the value obtained by multiplying the differential rotation of the second clutch CL2 by the transmission torque capacity of the second clutch CL2 is integrated over time. Estimate calorific value. When the CL2 estimated heat generation amount exceeds the heat generation amount threshold value, it can be determined that the driving force transmission system load is large. At this time, if the CL2 heat generation amount is calculated in consideration of the transmission oil temperature, the estimation accuracy of the CL2 heat generation amount is increased.

  In the first and second embodiments, the control device of the present invention is applied to an FR type hybrid vehicle. However, the control device of the present invention can of course be applied to an FF type hybrid vehicle.

E engine
CL1 1st clutch (1st engagement element)
MG Motor generator (motor)
CL2 2nd clutch (2nd engagement element)
AT automatic transmission 1 engine controller 2 motor controller 3 inverter 4 battery 5 first clutch controller 6 first clutch hydraulic unit 7 AT controller 8 second clutch hydraulic unit 9 brake controller 10 integrated controller 10a CL2 temperature sensor 10b longitudinal acceleration sensor 24 steering Angle sensor
100 Target drive torque calculator
200 Mode selection section
201 Road slope estimation calculation part (drive force transmission system load detection means)
300 Target charge / discharge calculator
400 Operating point command section
500 Shift control

Claims (3)

Engine,
And it makes the chromophore at the distal end over data to output the driving force of the vehicle,
A first fastening element interposed between the engine and the motor to connect and disconnect the engine and the motor;
A second fastening element interposed between the motor and the drive wheel to connect and disconnect the motor and the drive wheel;
A gradient estimation means for estimating a road surface gradient based on the detection value of the longitudinal acceleration sensor and outputting the estimated gradient,
When the estimated gradient is equal to or greater than a threshold value, the first fastening element is released or slip-fastened while the engine is operated at a predetermined rotational speed, and the second fastening element is set at a rotational speed lower than the predetermined rotational speed. Second fastening element protection travel control means for controlling the second fastening element protection travel mode for slip fastening,
Threshold value changing means for lowering the threshold value for shifting to the second engagement element protection travel mode when it is detected that a steering operation has been performed;
A control apparatus for a hybrid vehicle, comprising: In the hybrid vehicle control device according to claim 1 ,
The threshold value changing means, wherein the second predetermined threshold for transition to engagement element protection traveling mode, in the region where the absolute value steering angle from the steering angle sensor is greater than a steering judgment threshold, characterized by reducing the constant decline A control device for a hybrid vehicle. In the hybrid vehicle control device according to claim 1 ,
The threshold value changing means, the threshold value at which the transition to the second engagement element protection traveling mode, in the region where the steering angle absolute value from the steering angle sensor is greater than a steering judgment threshold, large variation decreases as the steering angle absolute value is greater A control device for a hybrid vehicle, characterized by being lowered by the width.