JP2017089811A - Control device of lockup clutch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve responsiveness when shifted to acceleration flexible control from deceleration flexible control.SOLUTION: In switching processing, when a state of a lockup clutch is in a deceleration flexible control state, a feedforward control part 11 calculates a target torque capacity of the lockup clutch without using an estimated differential rotation number which is calculated by a TC model 11f. According to the processing, it is unnecessary to offset a value of an integrated item which is calculated by an integrator 11d at deceleration flexible control when shifted to acceleration flexible control from deceleration flexible control, a delay of the rising of a torque capacity of the lockup clutch can be suppressed, and responsiveness when transited to acceleration flexible control from the deceleration flexible control can be improved.SELECTED DRAWING: Figure 2

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. The slip-up state of the lock-up clutch includes a deceleration flex control state in which the differential speed (engine speed-turbine speed) of the lock-up clutch is controlled to a negative value when the accelerator operation amount is zero, and the accelerator operation. There is an acceleration flex control state in which the differential speed of the lockup clutch is controlled to a positive value when the amount is greater than zero.

  In conventional lock-up clutch drive control, the polarity of the target differential rotation speed is not processed in the coast state where the accelerator operation amount is zero and in the drive state where the accelerator operation amount is greater than zero. The hydraulic pressure of the lockup clutch was controlled based on the target differential rotation speed (see Patent Document 1).

JP 2002-188717 A

  However, when the signs of the target differential rotational speed are different from each other as in the acceleration flex control and the deceleration flex control, the directions in which the torque capacity of the lockup clutch increases or decreases are also different from each other. For this reason, for example, when calculating the target torque capacity of the lockup clutch using the integral term when performing the flex control, the deceleration term is used by continuing to use the integral term regardless of the sign of the target differential rotation speed. Responsiveness when shifting from control to acceleration flex control may deteriorate. This is because the direction in which the integral term increases or decreases is different between the deceleration flex control and the acceleration flex control, so when shifting from the deceleration flex control to the acceleration flex control, the time required to cancel the integral term value during the deceleration flex control This is because the rise of the torque capacity of the lockup clutch is delayed.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a lockup clutch control device capable of improving responsiveness when shifting from deceleration flex control to acceleration flex control. .

  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. The lock required for feedforward control of the estimated differential rotational speed of the lockup clutch to the target differential rotational speed using the difference between the estimated differential rotational speed of the lockup clutch and the target differential rotational speed and an integral term. A feed-forward control unit that calculates a target torque capacity of the up clutch, a torque / hydraulic conversion unit that calculates a target hydraulic pressure of the lock-up clutch based on the target torque capacity, and the target torque capacity and the output torque of the engine A model unit that calculates an estimated differential rotation speed of the lockup clutch based on A control device for a lock-up clutch, wherein the feed-forward control unit is a deceleration flex control that controls the differential rotation speed of the lock-up clutch to a negative value when the state of the lock-up clutch is an accelerator operation amount of zero. When in the state, the target torque capacity of the lock-up clutch is calculated without using the estimated differential rotation speed calculated by the model unit.

  According to the lockup clutch control device of the present invention, when the lockup clutch is in the deceleration flex control state, the target torque capacity of the lockup clutch is determined without using the estimated differential rotational speed calculated by the model unit. calculate. This eliminates the need to cancel the integral term value during deceleration flex control when shifting from deceleration flex control to acceleration flex control, and delays the rise of the torque capacity of the lockup clutch. Can improve responsiveness when shifting from Acceleration Flex Control to Acceleration Flex Control.

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 switching processing according to an embodiment of the present invention. FIG. 4 is a timing chart for explaining the switching process according to the embodiment of the present invention.

  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.

  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 opening degree of the accelerator pedal (accelerator operation amount) is zero, the differential speed (engine speed ne−turbine speed nt) of the lock-up clutch 5 is a negative value. There are a decelerating flex control state in which the differential speed of the lockup clutch 5 is controlled to a positive value when the accelerator pedal opening is larger than zero. 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, the lockup clutch control device 10 according to an embodiment of the present invention includes a feedforward control unit 11, a feedback control unit 12, a target torque capacity calculation unit 13, a torque / hydraulic conversion unit 14, and A packing control unit 15 is provided.

  The feedforward control unit 11 includes a subtractor 11a, a multiplier 11b, a multiplier 11c, an integrator 11d, a gain multiplication unit 11e, and a TC model 11f.

  The subtractor 11a calculates a difference value between the estimated differential rotation speed of the lockup clutch 5 estimated by the torque converter model (TC model) 11f and the target differential rotation speed of the lockup clutch 5, and calculates the calculated difference value. It outputs to the multiplier 11b and the multiplier 11c.

  Multiplier 11b multiplies the difference value between the estimated differential rotational speed and the target differential rotational speed by inertia I of engine 2 and torque converter 4. The multiplier 11b outputs the multiplication value to the gain multiplication unit 11e.

  Multiplier 11c multiplies the difference value between the estimated differential rotational speed and the target differential rotational speed by a slope a of a characteristic line indicating the relationship between the engine rotational speed at the current engine rotational speed and the torque capacity of torque converter 4. The multiplier 11c outputs the multiplication value to the integrator 11d.

  The integrator 11d calculates an integral value of the multiplication value of the multiplier 11c, and outputs the calculated integration value to the gain multiplication unit 11e.

Gain multiplication section 11e calculates a value obtained by multiplying the feed-forward gain k _pi to the sum of the integral value outputted from the multiplier 11b is output from the multiplier and an integrator 11d as a target torque capacity Tlu of the lock-up clutch 5 To do. The gain multiplication unit 11e outputs the calculated target torque capacity Tlu of the lockup clutch 5 to the TC model 11f and the target torque capacity calculation unit 13.

  The TC model 11f estimates the differential rotation speed of the lockup clutch 5 using the target torque capacity Tlu of the lockup clutch 5 and the output torque Te of the engine 2 output from the gain multiplication unit 11e. The TC model 11f outputs the estimated differential rotational speed (estimated differential rotational speed) to the subtractor 11a.

  The feedback control unit 12 includes a subtracter 12a, a multiplier 12b, a multiplier 12c, an integrator 12d, and a gain multiplication unit 12e.

  The subtractor 12a calculates a difference value between the actual differential rotation speed of the lockup clutch 5 and the target differential rotation speed of the lockup clutch 5, and outputs the calculated difference value to the multiplier 12b and the multiplier 12c.

  Multiplier 12b multiplies the difference value between the actual differential speed and the target differential speed by inertia I of engine 2 and torque converter 4. The multiplier 12b outputs the multiplication value to the gain multiplication unit 12e.

  The multiplier 12c multiplies the difference value between the actual differential speed and the target differential speed by a slope a of a characteristic line indicating the relationship between the engine speed and the torque capacity of the torque converter 4 at the current engine speed. The multiplier 12c outputs the multiplication value to the integrator 12d.

  The integrator 12d calculates an integral value of the multiplication value of the multiplier 12c, and outputs the calculated integration value to the gain multiplication unit 12e.

The gain multiplication unit 12e calculates a value obtained by multiplying the sum of the multiplication value output from the multiplier 12b and the integration value output from the integrator 12d by the feedback gain k _fb as the target torque capacity Tlu of the lockup clutch 5. . The gain multiplier 12e outputs the calculated target torque capacity Tlu of the lockup clutch 5 to the target torque capacity calculator 13.

  The target torque capacity calculator 13 calculates the sum of the target torque capacity Tlu output from the gain multiplier 11e and the target torque capacity Tlu output from the gain multiplier 12e as the final target torque capacity Tlu. The final target torque capacity Tlu is output to the torque / hydraulic conversion unit 14.

  The torque / hydraulic conversion unit 14 converts the final target torque capacity Tlu of the lockup clutch 5 calculated by the target torque capacity calculation unit 13 into the hydraulic pressure (target hydraulic pressure) of the lockup clutch 5 and converts the converted target hydraulic pressure (target hydraulic pressure (target hydraulic pressure)). A control signal indicating (indicated pressure) is output to the packing control unit 15.

  The pack control unit 15 controls the hydraulic pressure of the lockup clutch 5 in accordance with the control signal output from the torque / hydraulic conversion unit 14.

  The lockup clutch control device 10 having such a configuration performs a deceleration flex control by executing the following switching process when switching the control system of the lockup clutch 5 from the deceleration flex control system to the acceleration flex control system. Improves responsiveness when shifting from Accelerated Flex Control. Hereinafter, with reference to FIG. 3 and FIG. 4, the operation of the lockup clutch control device 10 when executing the switching process according to the embodiment of the present invention will be described.

[Switching process]
FIG. 3 is a flowchart showing the flow of switching processing according to an embodiment of the present invention. FIG. 4 is a timing chart for explaining the switching process according to the embodiment of the present invention. The flowchart shown in FIG. 3 starts at the timing when the control device 10 is driven, and the switching process proceeds to the process of step S1.

  In the process of step S1, the control device 10 determines whether or not the current control state of the lockup clutch 5 is the acceleration flex control state. As a result of the determination, when the current control state of the lockup clutch 5 is not in the acceleration flex control state (step S1: No), the control device 10 advances the switching process to the process of step S2. On the other hand, when the current control state of the lockup clutch 5 is the acceleration flex control state (step S1: Yes), the control device 10 advances the switching process to the process of step S5.

  In the process of step S2, the control device 10 determines whether or not the current control state of the lockup clutch 5 is in the deceleration flex control state. As a result of the determination, when the current control state of the lockup clutch 5 is not in the deceleration flex control state (step S2: No), the control device 10 advances the switching process to the process of step S4. On the other hand, when the current control state of the lockup clutch 5 is the deceleration flex control state (step S2: Yes), the control device 10 advances the switching process to the process of step S3.

  In the process of step S3, the control device 10 sets the value of the integral term (FF integral term) calculated by the integrator 11d of the feedforward control unit 11 to zero (FF integral term 0 clear). That is, when the lockup clutch 5 is in the deceleration flex control state, the feedforward control unit 11 sets the target torque capacity of the lockup clutch 5 without using the estimated differential rotation speed calculated by the TC model 11f. calculate. Further, the control device 10 sets the lower limit value of the engine speed input to the TC model 11f as the turbine speed. According to such processing, when the control state of the lockup clutch 5 is switched to the acceleration flex control state, the value of the integral term calculated by the integrator 11d and the estimated differential rotational speed calculated by the TC model 11f are zero. Since it is started, the responsiveness when shifting from the deceleration flex control to the acceleration flex control can be improved. Thereby, the process of step S3 is completed and a series of switching processes are complete | finished. Thereafter, while the control device 10 is being driven, the control device 10 repeatedly executes the switching processing every time a predetermined time elapses after the switching processing is completed.

  In the process of step S4, the control device 10 calculates the initial value of the integral term (FF integral term) calculated by the integrator 11d of the feedforward control unit 11. Thereby, the process of step S4 is completed and a series of switching processes are complete | finished. Thereafter, while the control device 10 is being driven, the control device 10 repeatedly executes the switching processing every time a predetermined time elapses after the switching processing is completed.

  In the process of step S5, the control device 10 performs integration calculated by the integrator 11d of the feedforward control unit 11 in response to the sign of the target differential rotation speed of the lockup clutch 5 or the output torque of the engine 2 becoming negative. It is determined whether or not the value of the term (FF integral term) is held. As a result of the determination, when the value of the FF integral term is not held (step S5: No), the control device 10 advances the switching process to the process of step S8. On the other hand, when the value of the FF integral term is held (step S5: Yes), the control device 10 advances the switching process to the process of step S6.

  In the process of step S6, the control device 10 holds the value of the integral term (FF integral term) calculated by the integrator 11d of the feed-forward control unit 11, and the lower limit of the engine speed input to the TC model 11f. A value (no upper limit value) is set as the turbine speed (time t = t1 to t2 shown in FIG. 4). Thereby, the process of step S6 is completed and the switching process proceeds to the process of step S7.

  In the process of step S7, the control device 10 resumes the integration process by the integrator 11d of the feedforward control unit 11 in response to the sign of the target differential rotation speed of the lockup clutch 5 and the output torque of the engine 2 becoming positive. It is determined whether or not it has been done. If the integration process has not been resumed as a result of the determination (step S7: No), the control device 10 returns the switching process to the process of step S6. On the other hand, when the integration process is resumed (step S7: Yes), the control device 10 advances the switching process to the process of step S8.

  In the process of step S8, the feedforward control unit 11 uses the difference between the estimated differential rotational speed of the lockup clutch 5 output from the TC model 11f and the target differential rotational speed and the integral term calculated by the integrator 11d. The target torque capacity (FF torque) of the lockup clutch 5 is calculated (before time t = t1 or after time t = t2 shown in FIG. 4). Further, the control device 10 sets the lower limit value of the FF torque to zero. Thereby, the process of step S8 is completed and a series of switching processes are complete | finished. Thereafter, while the control device 10 is being driven, the control device 10 repeatedly executes the switching processing every time a predetermined time elapses after the switching processing is completed.

  As is clear from the above description, in the switching process according to an embodiment of the present invention, the feedforward control unit 11 is calculated by the TC model 11f when the lockup clutch 5 is in the deceleration flex control state. The target torque capacity of the lockup clutch 5 is calculated without using the estimated differential rotation speed. According to such processing, it is not necessary to cancel the value of the integral term calculated by the integrator 11d during the deceleration flex control when shifting from the deceleration flex control to the acceleration flex control, and the torque capacity of the lockup clutch 5 can be reduced. Since it is possible to suppress the delay of the rise, it is possible to improve the responsiveness when shifting from the deceleration flex control to the acceleration flex control.

  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 Lock-up clutch 10 Control apparatus 11 Feed forward control part 11a, 12a Subtractor 11b, 11c, 12b, 12c Multiplier 11d, 12d Integrator 11e, 12e Gain multiplication part 11f TC model 12 Feedback Control Unit 13 Target Torque Capacity Calculation Unit 14 Torque / Hydraulic Conversion Unit 15 Packing Control Unit

Claims (1)

A torque converter that transmits output torque of the engine to the transmission, and a lockup clutch that can directly connect the engine side and the transmission side of the torque converter. Feedforward control for calculating a target torque capacity of the lockup clutch necessary for feedforward control of the estimated differential rotational speed of the lockup clutch to the target differential rotational speed using a difference from the target differential rotational speed and an integral term A torque / hydraulic conversion unit that calculates a target hydraulic pressure of the lockup clutch based on the target torque capacity, and an estimated differential rotational speed of the lockup clutch based on the target torque capacity and the engine output torque. A lockup clutch control device comprising: a model unit for calculating,
The feedforward control unit is calculated by the model unit when the state of the lockup clutch is in a deceleration flex control state in which the differential rotation speed of the lockup clutch is controlled to a negative value when the accelerator operation amount is zero. A lockup clutch control device that calculates a target torque capacity of the lockup clutch without using the estimated difference rotational speed.

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