JP6531627B2 - Lock-up clutch control device - Google Patents

Description

  The present invention relates to a control device for a lockup clutch.

  Generally, there is known a vehicle provided with a torque converter for transmitting an output torque of an engine to a transmission, and a lockup clutch capable of directly connecting the engine side of the torque converter to the transmission side. In such a vehicle, the control device drives and controls the state of the lockup clutch to any one of the engaged state, the released state, and the slip state according to the accelerator operation amount and the vehicle speed. In the slip state of the lockup clutch, the decelerating flex control state in which the differential rotational speed of the lockup clutch is controlled to a negative value when the state of the torque converter is in the driven state (the differential rotational speed is negative). And the acceleration flex control state in which the differential rotation speed of the lockup clutch is controlled to a positive value when the state of the torque converter is in a drive state (a state in which the differential rotation speed is positive).

  When the state of the torque converter is in the driven state and when the state of the torque converter is in the driving state, the target torque capacity of the lockup clutch and the direction of increase or decrease of the command pressure (oil pressure command value) are different. Therefore, in the conventional lock-up clutch drive control, the torque converter is in the driven state by calculating the indicated pressure of the lock-up clutch using the absolute value of the target torque capacity of the lock-up clutch. The directions of increase and decrease of the target torque capacity and the command pressure of the lockup clutch are made to be the same when the state of the torque converter is in the drive state (see Patent Document 1).

Japanese Patent Laid-Open No. 2002-130461

  However, in general, the back pressure of the lockup clutch (circulation hydraulic pressure for cooling) and the pack end pressure (hydraulic pressure at which packing is completed) have variations with respect to design values. Then, when the actual value of the sum of the back pressure corresponding to the hydraulic pressure when the target torque capacity is 0 Nm and the pack end pressure is lower than the design value, the target torque capacity crosses 0 Nm. Therefore, when the command pressure of the lockup clutch is calculated using the absolute value of the target torque capacity of the lockup clutch, the command pressure rises again when the target torque capacity crosses 0 Nm, in other words, the command pressure Becomes larger than the target pressure, the differential rotational speed of the lockup clutch can not be controlled to the target differential rotational speed.

  Specifically, as shown in FIG. 6A, when the torque converter is in the driven state and the actual back pressure of the lockup clutch is smaller than the design value, the target torque capacity Tlu of the lockup clutch is (Line L3) may be smaller than zero. When the target torque capacity Tlu of the lockup clutch becomes smaller than 0, the instruction pressure Pslu (line L4) of the lockup clutch rises again. Similarly, as shown in FIG. 6 (b), when the torque converter is in the driven state and the actual back pressure of the lockup clutch is smaller than the design value, the target torque capacity Tlu of the lockup clutch is determined. Line L3) may be greater than zero. When the target torque capacity Tlu of the lockup clutch becomes smaller than 0, the command pressure Pslu (line L4) of the lockup clutch rises. In FIGS. 6 (a) and 6 (b), lines L1 and L2 respectively indicate the target differential rotational speed (target nslp) and the actual differential rotational speed (actual nslp) of the lockup clutch.

  The present invention has been made in view of the above problems, and an object thereof is to implement differential rotation of a lock-up clutch even when back pressure and pack end pressure of the lock-up clutch deviate from design values. It is an object of the present invention to provide a control device for a lockup clutch which can make the number follow a target differential rotation speed.

  The control device for the lockup clutch according to the present invention is mounted on a vehicle including a torque converter for transmitting the output torque of the engine to the transmission, and a lockup clutch capable of directly connecting the engine side of the torque converter to the transmission side. When the state of the torque converter is in the drive state, the state of the lockup clutch is controlled to an acceleration flex control state in which the differential rotational speed of the lockup clutch is controlled to a positive value. A control device for a lock-up clutch, which controls the state of the lock-up clutch to a decelerating flex control state for controlling the differential rotation speed of the lock-up clutch to a negative value when in the driven state. The lock necessary for feedback control of the differential rotational speed to the target differential rotational speed A feedback torque calculation unit that calculates a target torque capacity of the clutch as a feedback torque, and a sign of a target torque capacity of the lockup clutch when the state of the lockup clutch is controlled to the acceleration flex control state, the lockup The sign of the target torque capacity of the lockup clutch when controlling the state of the clutch to the deceleration flex control state is negative, and the state of the lockup clutch is controlled to the acceleration flex control state and the deceleration flex control state It is necessary to feed forward control the estimated differential rotation speed of the lockup clutch estimated by the model equation to the target differential rotation speed by treating the target torque capacity below zero as a negative value during operation. Said lockup A feedforward torque calculation unit that calculates a target torque capacity of the feedforward torque as the feedforward torque, and the sum of the feedback torque and the feedforward torque when the state of the lockup clutch is controlled to the acceleration flex control state The final target torque capacity of the lockup clutch is calculated, and when the state of the lockup clutch is controlled to the deceleration flex control state, a value obtained by multiplying the sum of the feedback torque and the feedforward torque by a minus is obtained. The target torque capacity calculation unit calculated as the final target torque capacity of the lockup clutch, and the lockup so that the torque capacity of the lockup clutch becomes the final target torque capacity calculated by the target torque capacity calculation unit clutch And a controller for controlling the hydraulic pressure of

  According to the controller of the lock-up clutch according to the present invention, the command pressure lower than the design value of the sum of the back-pressure of the lock-up clutch and the pack end pressure can be output. Can be made to follow the target rotational speed difference even if the value of the lockup clutch deviates from the design value.

FIG. 1 is a schematic view showing a control device of a lock-up clutch according to an embodiment of the present invention and a configuration of a vehicle to which the control device is applied. FIG. 2 is a block diagram showing a configuration of a control device of a lock-up clutch according to an embodiment of the present invention. FIG. 3 is a flow chart showing the flow of an indicated pressure calculation process according to an embodiment of the present invention. FIG. 4 is a diagram showing the target torque capacity of the lockup clutch and the increase / decrease direction of the command pressure when the torque converter is in the drive state and the driven state. FIG. 5 is a diagram showing changes in the target torque capacity and the command pressure of the lockup clutch when the torque converter is in the driving state and the driven state. FIG. 6 is a diagram showing changes in the target torque capacity and the command pressure of the lockup clutch when the torque converter is in the driving state and the driven state.

  Hereinafter, a control device for a lockup clutch according to an embodiment of the present invention will be described with reference to the drawings.

[Configuration of vehicle]
First, a configuration of a vehicle to which a control device for a lockup clutch according to an embodiment of the present invention is applied will be described with reference to FIG.

  FIG. 1 is a schematic view showing a control device of a lock-up clutch according to an embodiment of the present invention and a configuration of a vehicle to which the control device is applied. As shown in FIG. 1, a vehicle 1 to which a control device for a lockup clutch according to an embodiment of the present invention is applied includes an engine 2, a transmission 3, a torque converter 4, and a lockup clutch 5 as main components. Have as.

  The engine 2 is, for example, an internal combustion engine such as a gasoline engine or a diesel engine that generates driving force by combustion of fuel injected into a cylinder. The symbols ne and Te in the drawing respectively indicate the number of revolutions of the engine 2 (hereinafter referred to as the number of engine revolutions) and the output torque.

  The transmission 3 shifts an output torque Tt, which is the sum of the output torque Tc of the torque converter 4 and the output torque Tlu of the lockup clutch 5, and then transmits the output torque Tt to drive wheels (not shown). As the transmission 3, an automatic transmission (Automatic Transmission: AT), a continuously variable transmission (CVT), etc. can be illustrated. The symbol nt in the figure represents the turbine rotational speed, which is the rotational speed of the input shaft of the transmission 3 (the output shaft of the torque converter 4).

  The torque converter 4 includes a pump impeller 4a corresponding to an input rotary member connected to the crankshaft 2a of the engine 2 and a turbine impeller 4b corresponding to an output rotary member connected to the transmission 3 through the turbine shaft 3a. And a power transmission device that performs power transmission via a fluid. The symbol Te1 in the drawing represents the input torque of the torque converter 4.

  In torque converter 4 having such a configuration, in the driven state where the differential rotation speed (engine rotation speed ne-turbine rotation speed nt) is smaller than 0, the fluid is between pump wheel 4a and turbine wheel 4b. It flows from the turbine impeller 4b side to the pump impeller 4a side while the provided stator (not shown) is rotating (a state where the torque is not amplified). On the other hand, in the drive state where the differential rotation speed is greater than 0, the fluid flows from the pump impeller 4a side to the turbine impeller 4b side in a state where a stator (not shown) is fixed (a state where torque is amplified).

  The lockup clutch 5 mechanically couples the input side and the output side of the torque converter 4 mechanically when in the engaged state, and disables the fluid power transmission function by the pump impeller 4a of the torque converter 4 and the turbine impeller 4b. It is something that The lockup clutch 5 is configured to be drive-controlled by the control device 10 between an engaged state, a released state, and a slip state (half engaged state). Here, the engaged state means a state in which the input side and the output side of the torque converter 4 are directly engaged, and the released state means a state in which such an engaged state is released.

  In the slip state, an intermediate state between the engaged state and the released state, that is, a relative rotation between the input side and the output side of the torque converter 4 is permitted to some extent, and a state in which both are engaged partially means. Further, as the slip state of the lockup clutch 5, when the state of the torque converter 4 is in the driven state, the differential rotational speed (engine rotational speed ne-turbine rotational speed nt) of the lockup clutch 5 is controlled to a negative value. There is an acceleration flex control state in which the differential rotation speed of the lockup clutch 5 is controlled to a positive value when the deceleration flex control state and the state of the torque converter 4 are in the drive state. The symbol Te2 in the drawing represents the input torque of the lockup clutch 5.

[Configuration of control device]
Next, with reference to FIG. 2, the configuration of a control device for a lockup clutch according to an embodiment of the present invention will be described. FIG. 2 is a block diagram showing a configuration of a control device of a lockup clutch according to an embodiment of the present invention.

  As shown in FIG. 2, the control device 10 of the lock-up clutch according to an embodiment of the present invention is implemented by an electronic control unit (ECU) including a central processing unit (CPU), a storage device, and an input / output buffer etc. The CPU controls the overall operation of the control device 10 by executing a control program stored in the storage device. In the present embodiment, the control device 10 executes a control program stored in the storage device by a CPU (not shown), whereby the flex lock up controller (flex L / U controller) 11 and the torque / hydraulic conversion unit 12 And functions as the packing control unit 13. The flex L / U controller 11 includes an FF torque calculation unit 11 a, an FB torque calculation unit 11 b, and a target torque capacity calculation unit 11 c. The functions of these units will be described later.

  The lock-up clutch control device 10 having such a configuration performs the indicated pressure calculation process described below, whereby the back pressure or pack end pressure of the lock-up clutch 5 deviates from the design value. Even if the differential rotational speed of the lockup clutch 5 is made to follow the target differential rotational speed. Hereinafter, with reference to FIGS. 3 to 5, an operation of the control device 10 of the lockup clutch at the time of executing the indicated pressure calculation process according to the embodiment of the present invention will be described.

[Instructed pressure calculation process]
FIG. 3 is a flow chart showing the flow of an indicated pressure calculation process according to an embodiment of the present invention. FIG. 4 is a diagram showing the target torque capacity of the lockup clutch and the increase / decrease direction of the command pressure when the torque converter is in the drive state and the driven state. FIG. 5 is a diagram showing changes in the target torque capacity and the command pressure of the lockup clutch when the torque converter is in the driving state and the driven state. The flowchart shown in FIG. 3 starts at the timing at which the process of controlling the state of the lockup clutch 5 to the deceleration flex control state or the acceleration flex control state is started, and the command pressure calculation process proceeds to step S1.

  In the process of step S1, the target torque capacity of the lock-up clutch 5 (PI control) necessary for the control device 10 to perform feedback control (PI control) of the actual differential rotation speed of the lock-up clutch 5 to the target differential rotation speed (target nslp) Hereinafter, the value of FB torque is reset to zero. That is, since the variation amount of the output torque Te of the engine 2 or the back pressure of the lockup clutch 5 differs between when the state of the torque converter 4 is in the driven state and in the driven state, the acceleration flex control state and The FB torques in the deceleration flex control state are not taken over each other. Thus, the process of step S1 is completed, and the command pressure calculation process proceeds to the process of step S2.

  In the process of step S2, the FF torque calculation unit 11a sets the estimated differential rotation speed of the lockup clutch 5 estimated by the model equation to the target differential rotation speed (target nslp) with the target torque capacity below zero being a negative value. A target torque capacity (hereinafter referred to as an FF torque) of the lockup clutch 5 necessary for feedforward control is calculated. Further, the FB torque calculation unit 11 b calculates the FB torque, and outputs the calculated FB torque to the target torque capacity calculation unit 11 c. Note that the FB torque calculation unit 11b determines the actual rotational speed difference and the target in either case where the lockup clutch 5 is in the acceleration flex control state or in the case where the lockup clutch 5 is in the deceleration flex control state. It is desirable to calculate the FB torque using a common formula based on the deviation from the difference rotational speed. Control can be simplified by calculating the FB torque using a common formula. Thus, the process of step S2 is completed, and the command pressure calculation process proceeds to the process of step S3.

  In the process of step S3, the FF torque calculation unit 11a reverses the sign of the FF torque (deflation torque) calculated in the process of step S2 when the lockup clutch 5 is in the deceleration flex control state. It outputs to target torque capacity calculation part 11c. On the other hand, when the lockup clutch 5 is in the acceleration flex control state, the FF torque calculation unit 11a does not reverse the sign of the FF torque calculated in the process of step S2, and the target torque capacity calculation unit 11c. Output to Thus, the process of step S3 is completed, and the command pressure calculation process proceeds to the process of step S4.

  In the process of step S4, when the target torque capacity calculation unit 11c controls the state of the lockup clutch 5 to the acceleration flex control state, the sum (FF torque + FB torque) of the FF torque and the FB torque is used as the lockup clutch Calculated as the final target torque capacity Tlu of 5. On the other hand, when the state of the lockup clutch 5 is controlled to the deceleration flex control state, a value obtained by multiplying the sum of the FF torque and the FB torque by minus (-(FF torque + FB torque)) is the final value of the lockup clutch 5 It is calculated as a target torque capacity Tlu of Then, the target torque capacity calculation unit 11c outputs the calculated final target torque capacity Tlu of the lockup clutch 5 to the torque / oil pressure conversion unit 12c. As shown in FIG. 4, when the torque converter 4 is in the driving state, that is, when the state of the lockup clutch 5 is in the acceleration flex control state, regardless of the deviation E between the target differential speed and the actual differential speed, The target torque capacity Tlu and the command pressure Pslu increase and decrease in the same direction. On the other hand, when the torque converter 4 is in the driven state, that is, when the state of the lockup clutch 5 is in the decelerating flex control state, the target regardless of the deviation E between the target differential rotational speed and the actual differential rotational speed The torque capacity Tlu and the command pressure Pslu increase and decrease in opposite directions. Therefore, when the state of the lockup clutch 5 is controlled to the deceleration flex control state, the sum of the FF torque and the FB torque is multiplied by a minus to increase or decrease the final target torque capacity Tlu and the command pressure. Can be aligned. Thus, the process of step S4 is completed, and the command pressure calculation process proceeds to the process of step S5.

  In the process of step S5, the torque / oil pressure conversion unit 12 sets the final target torque capacity Tlu of the lockup clutch 5 calculated by the target torque capacity calculation unit 11c to the hydraulic pressure (instruction pressure) Pslu of the lockup clutch 5 (= Tlu). The control signal indicating the converted hydraulic pressure Pslu is output to the pack control unit 13 by converting it into × Ktp + back pressure (design value), Ktp = 1 / (pressure receiving area × effective radius)). Then, the packing control unit 13 controls the hydraulic pressure of the lockup clutch 5 in accordance with the control signal output from the torque / hydraulic conversion unit 12. Thereby, the process of step S5 is completed and a series of command pressure calculation processes are complete | finished. Thereafter, while the lockup clutch 5 is in the deceleration flex control state or the acceleration flex control state, the control device 10 repeatedly executes the command pressure calculation process each time a predetermined time has elapsed from the command pressure calculation process.

  As apparent from the above description, in the command pressure calculation process according to the embodiment of the present invention, the FF torque calculation unit 11a controls the state of the lockup clutch 5 to the acceleration flex control state and the deceleration flex control state. In this case, the target torque capacity below zero is treated as a negative value, and lockup necessary for feedforward control of the estimated differential rotation speed of the lockup clutch 5 estimated by the model equation to the target differential rotation speed The target torque capacity of the clutch 5 is calculated. Thereby, as shown by line L5 in FIGS. 5A and 5B, in either case where the state of torque converter 4 is in the driven state or in the case where the state of torque converter 4 is in the driven state. Since a command pressure lower than the design value of the sum of the back pressure of the lockup clutch 5 and the pack end pressure can be output, the back pressure or pack end pressure of the lockup clutch 5 deviates from the design value. However, the differential rotational speed of the lockup clutch 5 can be made to follow the target differential rotational speed.

  The embodiment to which the invention made by the present inventors has been applied has been described above, but the present invention is not limited by the description and the drawings that form a part of the disclosure of the present invention according to this embodiment. That is, other embodiments, examples, operation techniques and the like made by those skilled in the art based on the present embodiment are all included in the scope of the present invention.

Reference Signs List 1 vehicle 2 engine 3 transmission 4 torque converter 5 lockup clutch 10 control device 11 flex lockup controller (flex L / U controller)
11a FF torque calculation unit 11b FB torque calculation unit 11c target torque capacity calculation unit 12 torque / hydraulic conversion unit 13 packing control unit

Claims (1)

It is mounted on a vehicle equipped with a torque converter that transmits the output torque of the engine to the transmission, and a lockup clutch that can directly connect the engine side of the torque converter to the transmission side, and the torque converter is in a driven state. Sometimes the state of the lockup clutch is controlled to an acceleration flex control state in which the differential rotational speed of the lockup clutch is controlled to a positive value, which is the difference between the rotational speed of the engine and the rotational speed of the input shaft of the transmission. And a control device for a lockup clutch that controls the state of the lockup clutch to a decelerated flex control state of controlling the differential rotation speed of the lockup clutch to a negative value when the state of the torque converter is in a driven state. There,
A feedback torque calculation unit that calculates, as a feedback torque, a target torque capacity of the lockup clutch necessary to feedback control the actual differential rotation speed of the lockup clutch to the target differential rotation speed;
The sign of the target torque capacity of the lockup clutch when controlling the state of the lockup clutch to the acceleration flex control state is positive, and the lockup when controlling the state of the lockup clutch to the deceleration flex control state When the sign of the target torque capacity of the clutch is negative and the state of the lockup clutch is controlled to the acceleration flex control state and the decelerating flex control state, the target torque capacity below zero is a negative value. The lockup clutch estimated by the model equation of the vehicle including the rotational speed of the engine as input, the rotational speed of the input shaft of the transmission as output, and the differential rotational speed of the lockup clutch as a parameter. Feed forward control to the target differential speed And the feedforward torque-calculating section that calculates a target torque capacity of the lock-up clutch required as a feedforward torque for,
When the state of the lockup clutch is controlled to the acceleration flex control state, the sum of the feedback torque and the feedforward torque is calculated as the final target torque capacity of the lockup clutch, and A target torque capacity calculation unit that calculates a value obtained by multiplying the sum of the feedback torque and the feedforward torque by minus when the state is controlled to the deceleration flex control state as a final target torque capacity of the lockup clutch When,
A control unit that controls the hydraulic pressure of the lockup clutch so that the torque capacity of the lockup clutch becomes the final target torque capacity calculated by the target torque capacity calculation unit;
A control device for a lockup clutch, comprising:

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