JP5696430B2 - Vehicle control device - Google Patents

Description

  The present invention relates to a vehicle control device.

  As this type of technology, the technology described in Patent Document 1 below is disclosed. In this publication, the second clutch is slipped during EV traveling, and the second clutch transmission torque capacity is estimated from the torque and rotation speed of the motor generator at that time. The second clutch hydraulic pressure and the second clutch transmission torque capacity estimated value at that time are stored as learned values, and the second clutch transmission capacity with respect to the second clutch hydraulic pressure value is corrected using the learned values.

JP 2010-30429 A

When the second clutch transmission torque capacity is high and low, there is a large variation in the relationship between the second clutch hydraulic pressure and the transmission torque capacity. Therefore, in the above-described prior art, for example, the second clutch hydraulic pressure and the transmission are high when the transmission torque capacity is high. If the transmission torque capacity is estimated from the second clutch hydraulic pressure at the time of a low transmission torque capacity using the relationship with the torque capacity, the estimation accuracy may be lowered. In particular, in a hybrid vehicle that starts while slipping the second clutch, it is necessary to ensure high estimation accuracy for the transmission torque capacity near 0 [Nm] in order to ensure the durability and responsiveness of the second clutch. was there.
The present invention has been focused on the above problems, and an object of the present invention is to provide a vehicle control device that can increase the estimation accuracy of a low clutch transmission torque capacity.

In order to solve the above problems, the present invention, the engine is a driving state, the first engagement element is engaged, when the second engagement element is in a standby state or the slip state, the motor-generator Decrease the command oil pressure by a certain value while controlling the rotation speed, and if the amount of change in the output torque of the motor generator is less than the set value before and after the command oil pressure is reduced, the command oil pressure before the previous command oil pressure reduction is in the standby state Command oil pressure.

  Therefore, it is possible to ensure high estimation accuracy even when the transmission torque capacity of the fastening element is near 0 [Nm].

1 is an overall system diagram illustrating a hybrid vehicle according to a first embodiment. FIG. 3 is a control block diagram of the integrated controller according to the first embodiment. 3 is a target drive torque map of the first embodiment. 2 is a travel mode map according to the first embodiment. 3 is a target charge / discharge amount map of the first embodiment. 4 is a map showing an engine target speed in the WSC travel mode of the first embodiment. FIG. 3 is a schematic diagram illustrating an engine operating point setting process in the WSC traveling mode according to the first embodiment. 3 is a flowchart of standby hydraulic pressure setting processing according to the first embodiment. 3 is a time chart of the first embodiment.

[Example 1]
(Drive system configuration)
First, the drive system configuration of the hybrid vehicle will be described. FIG. 1 is an overall system diagram showing a hybrid vehicle driven by rear wheels of the first embodiment.

  As shown in FIG. 1, the drive system of the hybrid vehicle in the first embodiment includes an engine E, a first clutch CL1, a motor generator MG, a second clutch CL2, an automatic transmission AT, a propeller shaft PS, It has 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 valve opening degree of the throttle valve and the like are controlled based on a control command from the 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 the control created 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 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 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”). 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 generated by the second clutch hydraulic unit 8 based on a control command from the AT controller 7 described later. The fastening / release including slip fastening is controlled by the control hydraulic pressure. The second clutch CL2 corresponds to a fastening element of the present invention.

  The automatic transmission AT is a transmission that automatically switches the stepped gear ratio such as 5 forward speeds, 1 reverse speed, etc. according to the vehicle speed, accelerator opening, etc., and the second clutch CL2 is newly added as a dedicated clutch However, some frictional engagement elements are used among a plurality of frictional engagement elements that are engaged at each gear stage of the automatic transmission AT. Details will be described later.

  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 first clutch CL1 and the second clutch CL2 are, for example, wet multi-plate clutches that can continuously control the oil flow rate and hydraulic pressure with a proportional solenoid.

  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 that travels using only the power of the motor generator MG as a power source with the first clutch CL1 opened. 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. 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.

  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, 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.

[Control system configuration]
Next, the control system configuration 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. The AT controller 7, the second clutch hydraulic unit 8, the brake controller 9, and the integrated controller 10 are configured. 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 controls the engine operating point (Ne: engine speed, Te: engine torque) according to the target engine torque command from the integrated controller 10, etc. For example, to 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 inputs 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 generator) of the motor generator MG A command for controlling the rotation 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, and the battery SOC information is used for control information of the motor generator MG and is 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 / disengages the first clutch CL1 according to the first clutch control command from the integrated controller 10. A control command is output to the first clutch hydraulic unit 6. The 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 the accelerator opening sensor 16, the vehicle speed sensor 17, the second clutch hydraulic pressure sensor 18, and an inhibitor switch that outputs a signal corresponding to the position of the shift lever operated by the driver. In response to the second clutch control command from 10, a command for controlling engagement / disengagement of the second clutch CL2 is output to the second clutch hydraulic unit 8 in the AT hydraulic control valve. Information on the accelerator pedal 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 the sensor information from the wheel speed sensor 19 for detecting each wheel speed of the four wheels and the brake stroke sensor 20, and regenerates the required braking force obtained from the brake stroke BS when the brake is depressed, for example. When the braking force alone 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 N2out. The second clutch output speed sensor 22 for detecting the motor, the motor generator torque sensor 23 for detecting the motor generator torque TMG, the brake hydraulic pressure sensor 24, and the oil temperature (ATF temperature) in the automatic transmission AT are automatically detected. Information from the transmission oil temperature sensor 10a and the longitudinal acceleration sensor 10b for detecting longitudinal acceleration and the 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 the clutch CL1 and engagement / release control of the second clutch CL2 by a control command to the AT controller 7 are performed.

[Configuration of integrated controller]
FIG. 2 is a control block diagram of the integrated controller 10 according to the first embodiment. The integrated controller 10 includes a target driving force calculation unit 100, a travel mode selection unit 200, a target charge / discharge calculation unit 300, and an operating point command unit. 400, a shift control unit 500, a road surface gradient estimation unit 600, and a standby hydraulic pressure setting unit 700.

  The target driving force calculation unit 100 calculates the target driving force Td from the accelerator pedal opening APO and the vehicle speed VSP using the target driving force map shown in FIG.

  Traveling mode selection unit 200 selects a target mode based on the mode map. FIG. 4 shows a travel mode map. The travel mode map has an EV travel mode, a WSC travel mode, and an HEV travel mode, and calculates a target mode from the accelerator pedal 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 a predetermined value, the HEV travel mode or the WSC travel mode is forcibly selected.

  In the travel mode map of FIG. 4, the HEV → WSC switching line has a speed smaller than the idle speed of the engine E when the automatic transmission AT is in the first speed in the region below the predetermined accelerator pedal opening APO1. Is set in a region lower than the lower limit vehicle speed VSP1. In addition, since a large driving torque is required in a region where the accelerator pedal opening APO1 is greater than or equal to, 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 pedal 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 target charge / discharge calculation unit 300 calculates the target charge / discharge power tP from the battery SOC using the target charge / discharge amount map shown in FIG.

  The operating point command unit 400 uses the accelerator pedal opening APO, the target driving force Td, the target mode, the vehicle speed VSP, and the target charging / discharging power tP as a target for reaching these operating points, as a transient target engine torque. And a target motor generator torque, a target second clutch transmission torque capacity, a target shift stage of the automatic transmission AT, and a first clutch solenoid current command which is a transmission torque capacity command of the first clutch CL1.

  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. In the shift map, the target shift speed is set in advance based on the vehicle speed VSP and the accelerator pedal opening APO.

  The road surface gradient estimation unit 600 calculates the actual acceleration from the wheel speed acceleration average value of the wheel speed sensor 19 and the like, and estimates the road surface gradient from the deviation between this calculation result and the detected value of the longitudinal acceleration sensor 10b.

  The standby oil pressure setting unit 700 is a command oil pressure in a standby state in which the second clutch CL2 is maintained in a state immediately before engagement immediately before starting when starting in the WSC travel mode described later (starting while the second clutch CL2 is slipping). (Standby hydraulic pressure) is set. The standby oil pressure setting unit 700 calculates and obtains the standby oil pressure from the road surface gradient estimated value, the brake stroke, the ATF temperature, the motor generator torque, and the second clutch oil pressure. The shift control unit 500 drives and controls the solenoid valve in the automatic transmission AT according to the standby hydraulic pressure when in the standby state.

[About WSC drive mode]
Next, details of the WSC travel mode will be described. The WSC travel mode is characterized in that the engine E is maintained in an operating state, and has high responsiveness to a required drive torque change. Specifically, the first clutch CL1 is completely engaged, the second clutch CL2 is slip-controlled as a transmission torque capacity corresponding to the required drive torque, and the vehicle travels using the drive torque of the engine E and / or the motor generator MG.

  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 based on the idling engine speed for maintaining the self-sustaining rotation, and the idling engine speed further increases when the engine is idling up by warm-up operation of the engine. In addition, when the required drive torque is high, it may not be possible to quickly transition to the HEV travel mode.

  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 required 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 required 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.

  FIG. 6 is a map showing the target engine speed in the WSC travel mode, and FIG. 7 is a schematic diagram showing the engine operating point setting process in the WSC travel mode.

  When the driver operates the accelerator pedal in the WSC travel mode, the target engine speed characteristic corresponding to the accelerator pedal opening is selected based on FIG. 6, and the target engine speed corresponding to the vehicle speed is set along this characteristic. Is done. Then, the target engine torque corresponding to the target engine speed is calculated by the engine operating point setting process shown in FIG.

  Here, the operating point of the engine E is defined as a point defined by the engine speed and the engine torque. As shown in FIG. 7, it is desirable that the engine operating point be operated on a line (hereinafter referred to as “α line”) connecting operating points with high output efficiency of the engine E.

  However, when the engine speed is set as described above, an operating point away from the α line is selected depending on the accelerator pedal opening APO (required drive torque) by the driver. Therefore, in order to bring the engine operating point closer to the α line, the target engine torque is feedforward controlled to a value that takes the α line into consideration.

  On the other hand, the motor generator MG executes the rotational speed feedback control using the set engine rotational speed as the target rotational speed. Since the engine E and the motor generator MG are now in a direct connection state, the motor generator MG is controlled so as to maintain the target rotational speed, and the rotational speed of the engine E is also automatically feedback-controlled. It becomes.

  At this time, the torque output from the motor generator MG is automatically controlled so as to fill the deviation between the target engine torque determined in consideration of the α-ray and the required drive torque. In the motor generator MG, a basic torque control amount (regeneration / power running) is given so as to fill the deviation, and further feedback control is performed so as to match the target engine speed.

  When the required drive torque is smaller than the drive torque on the α line at a certain engine speed, the engine output efficiency increases as the engine output torque is increased. At this time, the motor generator MG recovers the energy corresponding to the increased output, and the torque input to the second clutch CL2 becomes the torque required by the driver, and efficient power generation is possible.

  However, since the upper limit of torque that can be generated is determined according to the state of the battery SOC, the required power generation output (SOC required power generation power) from the battery SOC and the deviation between the torque at the current operating point and the torque on the α line (α It is necessary to consider the magnitude relationship with the (line generated power).

  FIG. 7A is a schematic diagram when the α-ray generated power is larger than the SOC required generated power. Since the engine output torque cannot be increased above the SOC required power generation, the operating point cannot be moved on the α line. However, fuel efficiency is improved by moving to a more efficient point.

  FIG. 7B is a schematic diagram when the α-ray generated power is smaller than the SOC required generated power. Since the engine operating point can be moved on the α line within the SOC required power generation range, in this case, it is possible to generate power while maintaining the operating point with the highest fuel efficiency.

  FIG. 7C is a schematic diagram when the engine operating point is higher than the α line. When the operating point corresponding to the required drive torque is higher than the α line, the engine torque is reduced on the condition that the battery SOC has a margin, and the shortage is compensated by the power running of the motor generator MG. As a result, the required drive torque can be achieved while improving the fuel efficiency.

[When starting in WSC mode]
Next, the start time in the WSC travel mode will be described.
For example, as can be seen from the travel mode map of FIG. 4, the EV travel mode is in normal starting. However, even if the EV travel mode is selected as described above, if the battery SOC is equal to or less than the predetermined value, the target mode is forcibly selected as the HEV travel mode or the WSC travel mode.

  The engine E has a lower limit value based on the idling speed for maintaining the self-sustaining rotation, and the second clutch CL2 cannot be completely engaged even in the low vehicle speed range as at the start. The WSC traveling mode for slipping the clutch CL2 is selected.

  If the second clutch CL2 is slipped when the vehicle is stopped, the amount of heat generated by the second clutch CL2 may become excessive, and the second clutch CL2 may be damaged. On the other hand, if the second clutch CL2 is completely released even when the vehicle is stopped, even if the engagement hydraulic pressure of the second clutch CL2 is increased, the transmission torque capacity rises slowly, and the start response is deteriorated.

  Therefore, for example, when the vehicle is stopped and the driver releases the brake and enters a state immediately before starting (standby state), the engagement hydraulic pressure is increased until just before the second clutch CL2 starts slipping (standby hydraulic pressure), The rise of the transmission torque capacity at the time of start is made earlier.

  When the vehicle starts to start, the transmission torque capacity of the second clutch CL2 is gradually increased, and finally the second clutch CL2 is completely engaged to enter the HEV traveling mode.

[Standby oil pressure setting process]
FIG. 8 is a flowchart showing the flow of standby state oil pressure setting processing performed in the standby oil pressure setting unit 700.
In step S1, it is determined whether or not the mode is the WSC travel mode. When the mode is the WSC travel mode, the process proceeds to step S2, and when the mode is not the WSC travel mode, the process ends. The WSC travel mode means that the first clutch CL1 is engaged and the second clutch CL2 is in a state immediately before slip control or slip is started.

  In step S2, it is determined whether or not the ATF temperature is within the permitted range. When the ATF temperature is within the permitted range, the process proceeds to step S3, and when not within the permitted range, the process ends. When the ATF oil temperature is lower than the allowable range, it is necessary to increase the ATF oil temperature by slip-controlling the second clutch CL2 even when the vehicle is stopped. On the other hand, as described later, in the standby hydraulic pressure setting process, the second clutch CL2 is slip-controlled, but it is necessary not to perform the standby hydraulic pressure setting process when the ATF oil temperature is higher than the permitted range.

  In step S3, it is determined whether or not the estimated gradient is within the permitted range. If the estimated gradient is within the permitted range, the process proceeds to step S4, and if not, the process ends. As will be described later, in the standby hydraulic pressure setting process, the second clutch transmission torque capacity is decreased, so that the transmission torque to the drive wheels RL and RR is also reduced. The standby hydraulic pressure setting process is not performed because the vehicle may move backward when the transmission torque becomes small in a place where the gradient is high.

In step S4, it is determined whether or not the vehicle is stopped and the brake is ON. When the vehicle is stopped and the brake is ON, the process proceeds to step S5, and the vehicle is not stopped. If the brake is OFF, the process is terminated.
In step S5, the control start delay timer td is initialized, and the process proceeds to step S8.

In step S6, the control start delay timer td is counted up and the process proceeds to step S6.
In step S7, it is determined whether or not the control start delay timer td has passed the set time td1, and when it has elapsed, the process proceeds to step S7, and when it has not elapsed, the process proceeds to step S5.

  In step S8, the command second clutch hydraulic pressure is reduced by a set amount, and the process proceeds to step S9. In step S8, the command second clutch hydraulic pressure is reduced in a feedforward control regardless of the state of the second clutch hydraulic pressure or the like. The set amount for decreasing the command second clutch hydraulic pressure is set to the minimum hydraulic pressure at which the motor generator torque changes when the second clutch transmission torque capacity is decreased by decreasing the command second clutch hydraulic pressure. Further, the set amount for decreasing the command second clutch hydraulic pressure is set to a smaller value as the responsiveness of the second clutch transmission torque capacity is higher with respect to the change in the command second clutch hydraulic pressure.

In step S9, the response delay waiting time tw is initialized, and the process proceeds to step S10.
In step S10, the response delay waiting time tw is counted up, and the process proceeds to step S11.
In step S11, it is determined whether or not the response delay waiting time tw has passed the set time tw1, and when it has elapsed, the process proceeds to step S12, and when it has not elapsed, the process proceeds to step S10. The set time tw1 is set to a shorter time as the ATF oil temperature is higher.

In step S12, it is determined whether or not the change amount of the motor generator torque is less than the set value Tm1, and if it is less than the set value Tm1, the process proceeds to step S13, and if it is greater than or equal to the set value Tm1, the process proceeds to step S5.
In step S13, the command second clutch hydraulic pressure is further reduced, and the process proceeds to step S14. In step S13, the command second clutch hydraulic pressure is reduced in feedback control in response to the change in motor generator torque being less than the set value Tm1 in step S12.

In step S14, it is determined whether or not the change amount of the motor generator torque is substantially zero. If it is almost zero, the process proceeds to step S15, and if not, the process proceeds to step S5.
In step S15, the hydraulic pressure before the previous command second clutch hydraulic pressure reduction process (step S8) is set as the standby hydraulic pressure, and the process proceeds to step S16. Here, a value obtained by adding the safe offset hydraulic pressure to the hydraulic pressure before the previous command second clutch hydraulic pressure reduction process (step S8) is set as the standby hydraulic pressure. It is not necessary to add the safety offset hydraulic pressure.

  In step S16, the command second clutch hydraulic pressure is returned to the standby hydraulic pressure. At this time, the command second clutch oil pressure is raised to the standby oil pressure or higher, then lowered to less than the standby oil pressure, and then gradually raised to the standby oil pressure, and the process is terminated.

[Standby hydraulic pressure setting operation]
FIG. 9 is a time chart showing the required drive torque, brake stroke, vehicle speed, actual motor generator torque, oil pressure drop equivalent motor generator torque, actual second clutch transmission torque capacity, and command second clutch hydraulic pressure.

  The requested drive torque is a drive torque requested by the driver, and can be obtained from the accelerator pedal opening APO or the like. The motor generator torque corresponding to the decrease in hydraulic pressure is estimated in consideration of the output torque that decreases because the load on the motor generator MG decreases along with the decrease in the second clutch transmission torque capacity as the command second clutch hydraulic pressure decreases. Torque.

  Currently, in the WSC driving mode, the ATF temperature is within the permitted range, and the estimated gradient is within the permitted range. When the required drive torque is reduced at time t1 and the brake stroke is in the brake ON state, the process proceeds from step S1 to step S2 to step S3 to step S4 in the flowchart of FIG.

From time t1 to time t2, the process proceeds from step S5 to step S6 to step S7, and the count-up process in step S6 is repeated until the control start delay timer td exceeds the set time td1.
At time t2, the control start delay timer td exceeds the set time td1, and the process proceeds to step S8 to decrease the command second clutch hydraulic pressure.

  From time t2 to time t3, the process proceeds from step S9 to step S10 to step S11. In order to wait for a response delay until the second clutch hydraulic pressure actually decreases and the second clutch transmission torque capacity decreases, a response delay waiting time The count-up process in step S10 is repeated until tw exceeds the set time tw1.

From time t3 to time t4, it is determined in step S12 whether or not the amount of change in motor generator torque is less than the set value Tm1.
Here, since the change amount of the motor generator torque is equal to or larger than the set value Tm1, the process proceeds to step S5. From time t4 to time t5, the process proceeds from step S5 to step S6 to step S7, and the count-up process in step S6 is repeated until the control start delay timer td exceeds the set time td1.

At time t5, the control start delay timer td exceeds the set time td1, and the process proceeds to step S8 to decrease the command second clutch hydraulic pressure.
From time t5 to time t6, the process proceeds from step S9 to step S10 to step S11. In order to wait for a response delay until the second clutch hydraulic pressure actually decreases and the second clutch transmission torque capacity decreases, a response delay waiting time The count-up process in step S10 is repeated until tw exceeds the set time tw1.

From time t6 to time t7, it is determined in step S12 whether or not the motor generator torque change amount is less than the set value Tm1.
Here, since the change amount of the motor generator torque is less than the set value Tm1, the process proceeds to step S13, and the command second clutch hydraulic pressure is further reduced from time t7 to time t8.

The process proceeds to step S14, and when there is almost no change in motor generator torque at time t8, the process proceeds from step S15 to step S16. In step S15, a value obtained by adding the safe offset hydraulic pressure to the hydraulic pressure before the previous command (second time t5) command second clutch hydraulic pressure reduction process (step S8) is set as the standby hydraulic pressure.

  From time t8 to time t10, the command second clutch hydraulic pressure is returned to the standby hydraulic pressure in step S16. At this time, from time t8 to time t9, the command second clutch hydraulic pressure is raised to the standby hydraulic pressure or higher, then at the time t9, it is lowered to less than the standby hydraulic pressure, and then gradually raised to the standby hydraulic pressure, and the process is terminated.

[Action]
The relationship between the second clutch hydraulic pressure and the transmission torque capacity varies greatly when the second clutch transmission torque capacity is high and low. Therefore, for example, if the transmission torque capacity is estimated from the second clutch hydraulic pressure at a low transmission torque capacity using the relationship between the second clutch hydraulic pressure and the transmission torque capacity at a high transmission torque capacity, the estimation accuracy may be lowered. was there. In particular, in a hybrid vehicle that starts while slipping the second clutch, it is necessary to ensure high estimation accuracy for the transmission torque capacity near 0 [Nm] in order to ensure the durability and responsiveness of the second clutch. was there.

  Therefore, in the first embodiment, the motor generator torque is reduced before and after the command second clutch hydraulic pressure is reduced by decreasing the command second clutch hydraulic pressure by a constant value while controlling the rotational speed of the motor generator MG with the second clutch CL2 engaged. When the amount of change is less than the set value Tm1, the previous command second clutch oil pressure is set to the standby oil pressure.

  This makes it possible to ensure high estimation accuracy even when the second clutch transmission torque capacity is near 0 [Nm]. Therefore, in the slip start control in the WSC travel mode, immediately before the start, the engagement hydraulic pressure is increased to just before the second clutch CL2 starts to slip, thereby protecting the second clutch CL2 and ensuring the response at the start. be able to.

In the first embodiment, the command second clutch hydraulic pressure is decreased every minimum value at which a change in motor generator torque can be detected.
Thereby, the detection precision of standby oil pressure can be raised.

In the first embodiment, the higher the responsiveness of the second clutch transmission torque capacity with respect to the command second clutch hydraulic pressure, the smaller the fixed value for decreasing the command second clutch hydraulic pressure.
Thereby, the sudden change of the second clutch transmission torque capacity can be prevented, and the sudden change of the transmission torque to the left and right drive wheel sides RL and RR can be suppressed.

〔effect〕
(1) A motor generator MG that outputs a driving torque of the vehicle, and is interposed between the motor generator MG and the left and right driving wheels RL and RR (driving wheels) to connect and disconnect the motor generator MG and the left and right driving wheels RL and RR. The second clutch CL2 (engagement element), the second clutch hydraulic unit 8 (engagement element hydraulic unit) that controls the transmission torque capacity of the second clutch CL2, and the state immediately before the second clutch CL2 slips before starting the vehicle. A shift control unit 500 (engaging element hydraulic unit control means) that outputs a command second clutch hydraulic pressure to the second clutch hydraulic unit 8 so as to slip the second clutch CL2 when the vehicle starts from a standby state, and a second clutch CL2 In the engaged state, the command second clutch hydraulic pressure is decreased by a certain value while controlling the rotation speed of the motor generator MG, and before and after the command second clutch hydraulic pressure is decreased, the mode is reduced. A standby hydraulic pressure setting unit 700 (standby hydraulic pressure setting means) that sets the previous command second clutch hydraulic pressure as the standby hydraulic pressure (the commanded second clutch hydraulic pressure in the standby state) when the change amount of the generator torque is less than the set value Tm1; It was.

  Therefore, high estimation accuracy can be ensured even when the second clutch transmission torque capacity is near 0 [Nm]. Therefore, in the slip start control in the WSC travel mode, immediately before the start, the engagement hydraulic pressure is increased to just before the second clutch CL2 starts to slip, thereby protecting the second clutch CL2 and ensuring the response at the start. be able to.

(2) In the standby hydraulic pressure setting unit 700, the command second clutch hydraulic pressure is decreased by every minimum value at which a change in motor generator torque can be detected.
Therefore, the detection accuracy of the standby hydraulic pressure can be increased.

(3) In the standby hydraulic pressure setting unit 700, the higher the responsiveness of the second clutch transmission torque capacity with respect to the command second clutch hydraulic pressure, the smaller the fixed value for decreasing the command second clutch hydraulic pressure.
Therefore, a sudden change in the second clutch transmission torque capacity can be prevented, and a sudden change in the transmission torque to the left and right drive wheel sides RL and RR can be suppressed.

[Other embodiments]
The best mode for carrying out the present invention has been described based on the first embodiment. However, the specific configuration of the present invention is not limited to the first embodiment and does not depart from the gist of the present invention. Any change in the design of the range is included in the present invention.

  For example, although the FR type hybrid vehicle has been described in the first embodiment, it may be an FF type hybrid vehicle.

MG motor generator
RL Left drive wheel (drive wheel)
RR Right drive wheel (drive wheel)
CL2 2nd clutch (engagement element)
8 Second clutch hydraulic unit (fastening element hydraulic unit)
500 Shift control unit (fastening element hydraulic unit control means)
700 Standby oil pressure setting unit (Standby oil pressure setting means)

Claims (3)

Engine,
A motor generator for outputting the driving torque of the vehicle;
A first fastening element interposed between the engine and the motor generator to connect and disconnect the engine and the motor generator;
A second fastening element interposed between the motor generator and the drive wheel to connect and disconnect the motor generator and the drive wheel;
A second engagement element hydraulic unit for controlling the transmission torque capacity of the second engagement element,
A fastening element hydraulic unit that outputs a command hydraulic pressure to the second fastening element hydraulic unit so as to slip the second fastening element when the vehicle starts from a standby state in which the second fastening element is kept in a state immediately before slipping before starting the vehicle. Control means;
When the engine is in a driving state, the first fastening element is in a fastening state, and the second fastening element is in a standby state or a slip state , the command hydraulic pressure is kept constant while controlling the rotational speed of the motor generator. When the change amount of the output torque of the motor generator is less than a set value before and after the command hydraulic pressure is decreased, the command hydraulic pressure before the previous command hydraulic pressure is decreased is the command hydraulic pressure in the standby state. Standby hydraulic pressure setting means,
A vehicle control device characterized by comprising: The vehicle control device according to claim 1,
The vehicle control apparatus according to claim 1, wherein the standby state hydraulic pressure setting means decreases the command hydraulic pressure by a minimum value at which a change in the output torque of the motor generator can be detected. The vehicle control device according to claim 1,
The vehicle control apparatus according to claim 1, wherein the standby state hydraulic pressure setting means sets a constant value for decreasing the command hydraulic pressure to a smaller value as the response of the transmission torque capacity of the fastening element to the command hydraulic pressure is higher.

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