JP2017089781A - Control device of lockup clutch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a differential rotation number of a lockup clutch follow a target differential rotation number even if the back pressure and the pack-end pressure of the lockup clutch is deviated from a design value.SOLUTION: When a control device 10 controls a state of a lockup clutch 5 to an acceleration flexible control state and a deceleration flexible control state, a target torque capacity going below zero is handled as a negative value, and a target torque capacity of the lockup clutch 5 necessary for feedforward-controlling an estimated differential rotation number of the lockup clutch 5 which is estimated by a model formula to a target differential rotation number is thereby calculated. By this constitution, since indication pressure which is lower than a design value of a sum of the back pressure and the pack-end pressure of the lockup clutch 5 can be outputted, even if the back pressure and the pack-end pressure of the lockup clutch 5 are deviated from the design value, a differential rotation number of the lockup clutch 5 can be made to follow the target differential rotation number.SELECTED DRAWING: Figure 1

Description

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

  In general, a vehicle is known that includes a torque converter that transmits engine output torque to a transmission, and a lock-up clutch that can directly connect the engine side and the transmission side of the torque converter. 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. Note that the slip-up state of the lock-up clutch is a deceleration flex control state in which the differential speed of the lock-up clutch is controlled to a negative value when the torque converter is in a driven state (the differential speed is negative). In addition, there is an acceleration flex control state in which the differential rotation speed of the lockup clutch is controlled to a positive value when the torque converter is in a driving state (a state where the differential rotation speed is positive).

  The direction of increase / decrease in the target torque capacity and command pressure (hydraulic command value) of the lockup clutch differs between when the torque converter is in the driven state and when the torque converter is in the driven state. For this reason, in the conventional drive control of the lockup clutch, when the command value of the lockup clutch is calculated using the absolute value of the target torque capacity of the lockup clutch, the torque converter is in the driven state. The target torque capacity of the lock-up clutch and the direction of increase / decrease of the command pressure are made uniform when the torque converter is in the driving state (see Patent Document 1).

JP 2002-130461 A

  However, in general, the back pressure (cooling circulation hydraulic pressure) and the pack end pressure (hydraulic pressure at which packing is completed) of the lock-up clutch vary from the design value. When the actual value of the sum of the back pressure and the pack end pressure corresponding to the hydraulic pressure when the target torque capacity is 0 Nm is lower than the design value, the target torque capacity goes over 0 Nm. For this reason, 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 increases again when the target torque capacity crosses 0 Nm. In other words, the command pressure When the pressure becomes larger than the target pressure, the differential rotation speed of the lockup clutch cannot be controlled to the target differential rotation speed.

  Specifically, as shown in FIG. 6A, when the torque converter is in the driving state and the actual back pressure of the lock-up clutch is smaller than the design value, the target torque capacity Tlu of the lock-up clutch. (Line L3) may be smaller than zero. When the target torque capacity Tlu of the lockup clutch becomes smaller than 0, the lockup clutch command pressure Pslu (line L4) increases again. Similarly, as shown in FIG. 6B, 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 ( 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 increases. In FIGS. 6A and 6B, lines L1 and L2 indicate the target differential rotation speed (target nslp) and the actual differential rotation speed (actual nslp) of the lockup clutch, respectively.

  The present invention has been made in view of the above problems, and its purpose is to perform differential rotation of the lockup clutch even when the back pressure or pack end pressure of the lockup clutch is deviated from the design value. An object of the present invention is to provide a control device for a lock-up clutch capable of causing the number to follow the target differential rotation speed.

  A lockup clutch control device according to the present invention is mounted on a vehicle including a torque converter that transmits output torque of an engine to a transmission, and a lockup clutch that can directly connect an engine side and a transmission side of the torque converter. When the torque converter is in the drive state, 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 that controls the lock-up clutch to a deceleration flex control state that controls the differential rotation speed of the lock-up clutch to a negative value when in the drive state. The lock required 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 clutch as a feedback torque, and a sign of the target torque capacity of the lockup clutch when controlling the lockup clutch state to the acceleration flex control state is positive, the lockup The sign of the target torque capacity of the lock-up clutch when controlling the clutch state to the deceleration flex control state is negative, and the state of the lock-up clutch is controlled 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, which is necessary for feedforward control of the estimated differential rotational speed of the lockup clutch estimated by the model formula to the target differential rotational speed. The lock-up clutch A feedforward torque calculation unit that calculates a target torque capacity of the feedforward torque, and when controlling the lockup clutch state 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 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 negative value is obtained. A target torque capacity calculation unit that calculates 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 control unit for controlling the hydraulic pressure of the motor.

  According to the lockup clutch control device of the present invention, it is possible to output a command pressure lower than the design value of the sum of the back pressure of the lockup clutch and the pack end pressure. Even when is deviated from the design value, the differential rotational speed of the lockup clutch can be made to follow the target differential rotational speed.

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

  A lockup clutch control device according to an embodiment of the present invention will be described below with reference to the drawings.

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

  FIG. 1 is a schematic diagram showing a configuration of a lockup clutch control device and a vehicle to which the control device is applied, which is an embodiment of the present invention. As shown in FIG. 1, a vehicle 1 to which a lockup clutch control device 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. As prepared.

  The engine 2 is an internal combustion engine such as a gasoline engine or a diesel engine that generates a driving force by combustion of fuel injected into a cylinder, for example. In addition, the code | symbol ne and Te in a figure represent the rotation speed (henceforth, engine speed) and output torque of the engine 2, respectively.

  The transmission 3 shifts the 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 it to drive wheels (not shown). Examples of the transmission 3 include an automatic transmission (AT) and a continuously variable transmission (CVT). In addition, the code | symbol nt in a figure represents the turbine rotational speed which is the rotational speed of the input shaft (output shaft of the torque converter 4) of the transmission 3. FIG.

  The torque converter 4 includes a pump impeller 4a corresponding to an input rotating member connected to the crankshaft 2a of the engine 2 and a turbine impeller 4b corresponding to an output rotating member connected to the transmission 3 via the turbine shaft 3a. And a fluid power transmission device that transmits power through a fluid. Note that the symbol Te <b> 1 in the drawing represents the input torque of the torque converter 4.

  In the torque converter 4 having such a configuration, in a driven state where the differential rotational speed (engine rotational speed ne−turbine rotational speed nt) is smaller than 0, fluid is interposed between the pump impeller 4a and the turbine impeller 4b. It flows from the turbine impeller 4b side to the pump impeller 4a side in a state where the provided stator (not shown) is rotating (a state where torque is not amplified). On the other hand, in a driving state where the differential rotational speed is greater than 0, 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 lock-up clutch 5 mechanically directly connects the input side and the output side of the torque converter 4 when engaged, and disables the fluid power transmission function of the torque converter 4 by the pump impeller 4a and the turbine impeller 4b. It is to make it. The lock-up clutch 5 is configured to be driven and controlled between an engaged state, a released state, and a slip state (half-engaged state) under the control of the control device 10. Here, the engaged state means a state where the input side and the output side of the torque converter 4 are directly engaged, and the released state means a state where such an engaged state is released.

  The slip state is an intermediate state between the engaged state and the released state, that is, a state in which the relative rotation between the input side and the output side of the torque converter 4 is allowed to some extent and both are partially engaged. means. Further, as the slip state of the lock-up clutch 5, when the torque converter 4 is in the driven state, the differential speed (engine speed ne-turbine speed nt) of the lock-up clutch 5 is controlled to a negative value. There are a deceleration flex control state and an acceleration flex control state in which the differential rotational speed of the lockup clutch 5 is controlled to a positive value when the torque converter 4 is in the drive state. A symbol Te <b> 2 in the drawing represents an input torque of the lockup clutch 5.

[Configuration of control device]
Next, with reference to FIG. 2, the structure of the control apparatus of the lockup clutch which is one Embodiment of this invention is demonstrated. FIG. 2 is a block diagram showing the configuration of the lockup clutch control apparatus according to the embodiment of the present invention.

  As shown in FIG. 2, a lockup clutch control device 10 according to an embodiment of the present invention includes an unillustrated CPU (Central Processing Unit), a storage device, an ECU (Electronic Control Unit) including an input / output buffer, and the like. The CPU is configured to execute the control program stored in the storage device, thereby controlling the operation of the entire control device 10. In the present embodiment, the control device 10 executes a control program stored in a storage device by a CPU (not shown), whereby a flex lockup controller (flex L / U controller) 11, a torque / hydraulic conversion unit 12, And it functions as the packing control unit 13. The flex L / U controller 11 includes an FF torque calculator 11a, an FB torque calculator 11b, and a target torque capacity calculator 11c. The functions of these units will be described later.

  The lockup clutch control device 10 having such a configuration is executed when the back pressure and the pack end pressure of the lockup clutch 5 are deviated from the design values by executing the indicated pressure calculation process shown below. Even if it exists, the differential rotation speed of the lockup clutch 5 is made to follow a target differential rotation speed. Hereinafter, with reference to FIGS. 3 to 5, an operation of the lockup clutch control device 10 when executing the command pressure calculation process according to the embodiment of the present invention will be described.

[Indicated pressure calculation processing]
FIG. 3 is a flowchart showing the flow of the command pressure calculation process according to the embodiment of the present invention. FIG. 4 is a diagram illustrating the increase / decrease direction of the target torque capacity and the command pressure of the lockup clutch when the torque converter is in the driven 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 a driving state and a driven state. The flowchart shown in FIG. 3 starts at the timing when 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 the process of step S1.

  In the processing of step S1, the control device 10 performs a target torque capacity (the target torque capacity of the lockup clutch 5 (PI control) required for feedback control (PI control) of the actual differential speed of the lockup clutch 5 to the target differential speed (target nslp). Hereinafter, the value of FB torque is reset to zero. That is, the amount of variation in the output torque Te of the engine 2 and the back pressure of the lockup clutch 5 is different between when the torque converter 4 is in the driven state and when it is in the driven state. The FB torques in the deceleration flex control state are not taken over from each other. Thereby, 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 rotational speed of the lockup clutch 5 estimated by the model formula to the target differential rotational speed (target nslp), assuming that the target torque capacity below zero is a negative value. A target torque capacity (hereinafter referred to as FF torque) of the lock-up clutch 5 necessary for feedforward control is calculated. Further, the FB torque calculation unit 11b calculates the FB torque, and outputs the calculated FB torque to the target torque capacity calculation unit 11c. Note that the FB torque calculation unit 11b determines the actual rotational speed and the target in both cases when the lockup clutch 5 is in the acceleration flex control state and when the lockup clutch 5 is in the deceleration flex control state. It is desirable to calculate the FB torque using a common mathematical formula based on the deviation from the differential rotational speed. Control can be simplified by calculating the FB torque using a common formula. Thereby, 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 (decrease flex torque) calculated in the process of step S2 when the lockup clutch 5 is in the deceleration flex control state. It outputs to the 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 uses the FF torque calculated in the process of step S2 as the target torque capacity calculation unit 11c without reversing the sign. Output to. Thereby, 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 is controlling the state of the lockup clutch 5 to the acceleration flex control state, the sum of the FF torque and the FB torque (FF torque + FB torque) is locked to the lockup clutch. 5 as the final target torque capacity Tlu. 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. Is calculated as a target torque capacity Tlu. Then, the target torque capacity calculation unit 11c outputs the calculated final target torque capacity Tlu of the lockup clutch 5 to the torque / hydraulic conversion unit 12c. As shown in FIG. 4, when the torque converter 4 is in the driving state, that is, when 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 increase / decrease direction of the target torque capacity Tlu and the command pressure Pslu is the same direction. On the other hand, when the torque converter 4 is in a driven state, that is, when the lockup clutch 5 is in the deceleration flex control state, the target speed is not related to the deviation E between the target differential speed and the actual differential speed. The increasing / decreasing directions of the torque capacity Tlu and the command pressure Pslu are reversed. Therefore, when the lock-up clutch 5 is controlled to the deceleration flex control state, the final target torque capacity Tlu and the direction of increase / decrease of the command pressure are changed by multiplying the sum of the FF torque and the FB torque by minus. Can be aligned. Thereby, 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 / hydraulic conversion unit 12 uses the final target torque capacity Tlu of the lockup clutch 5 calculated by the target torque capacity calculation unit 11c as the oil pressure (indicated pressure) Pslu (= Tlu) of the lockup clutch 5. × Ktp + back pressure (design value), Ktp = 1 / (pressure receiving area × effective radius)), and outputs a control signal indicating the converted hydraulic pressure Pslu to the pack control unit 13. The pack control unit 13 controls the hydraulic pressure of the lockup clutch 5 according to the control signal output from the torque / hydraulic conversion unit 12. Thereby, the process of step S5 is completed and a series of instruction | 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 every time a predetermined time elapses from the command pressure calculation process.

  As is clear 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. The target torque capacity below zero is treated as a negative value when the engine is in the locked state, and the lockup required for feedforward control of the estimated differential rotational speed of the lockup clutch 5 estimated by the model formula to the target differential rotational speed is performed. A target torque capacity of the clutch 5 is calculated. As a result, as indicated by the line L5 in FIGS. 5A and 5B, the torque converter 4 is in the driven state and the torque converter 4 is in the driven state. Since the command pressure lower than the design value of the sum of the back pressure and the pack end pressure of the lockup clutch 5 can be output, the back pressure and the pack end pressure of the lockup clutch 5 are shifted from the design values. 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 is applied has been described above, but the present invention is not limited by the description and the drawings that constitute a part of the disclosure of the present invention. That is, other embodiments, examples, operational 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.

DESCRIPTION OF SYMBOLS 1 Vehicle 2 Engine 3 Transmission 4 Torque converter 5 Lockup clutch 10 Control apparatus 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 pack packing control unit

Claims (1)

A torque converter that transmits engine output torque to a transmission and a lockup clutch that can directly connect the engine side and the transmission side of the torque converter are mounted on a vehicle, and the state of the torque converter is in a driving state. Sometimes the state of the lock-up clutch is controlled to an acceleration flex control state that controls the differential rotation speed of the lock-up clutch to a positive value, and when the torque converter is in a driven state, the state of the lock-up clutch is changed. A control device for a lock-up clutch that controls a deceleration flex control state that controls the differential rotation speed of the lock-up clutch to a negative value,
A feedback torque calculation unit that calculates a target torque capacity of the lockup clutch necessary for feedback control of the actual differential rotation speed of the lockup clutch to a target differential rotation speed; and
The sign of the target torque capacity of the lockup clutch when controlling the lockup clutch state to the acceleration flex control state is positive, and the lockup when controlling the lockup clutch state to the deceleration flex control state The sign of the target torque capacity of the clutch is negative, and the target torque capacity below zero is set to a negative value when the lockup clutch state is controlled to the acceleration flex control state and the deceleration flex control state. By processing the feed-forward torque, the target torque capacity of the lock-up clutch necessary for feed-forward control of the estimated differential rotational speed of the lock-up clutch estimated by the model formula to the target differential rotational speed is calculated as feed-forward torque. A torque calculator;
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 the lockup clutch A target torque capacity calculation unit that calculates a value obtained by multiplying the sum of the feedback torque and the feed forward torque by a negative value as the final target torque capacity of the lockup clutch when the state is controlled to the deceleration flex control state 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 lock-up clutch comprising:

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