JP2016173123A - Slip control device of lock-up clutch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress degradation of responsiveness to acceleration request when shifting from deceleration flex lock-up control to acceleration flex lock-up control.SOLUTION: In slip control processing, a control device holds a hydraulic command value (lock-up indication pressure) of a lock-up clutch to prevent lowering of the hydraulic command value of the lock-up clutch, and then lowers the hydraulic command value of the lock-up clutch after the lapse of a prescribed time, when shifting from the deceleration flex lock-up control where a target difference in rotating speed of a torque converter is negative, to acceleration flex lock-up control where the target difference in rotating speed of the torque converter is positive according to an increase in an accelerator opening (time t=t1).SELECTED DRAWING: Figure 3

Description

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

  Conventionally, in a vehicle having a lock-up clutch capable of directly connecting input / output members of a fluid-type power transmission device that constitutes a part of a power transmission path between an engine and a drive wheel, the slip amount of the lock-up clutch is reduced. A slip control device for a lock-up clutch that controls a difference in rotational speed between an input shaft and an output shaft of a fluid-type power transmission device (hereinafter referred to as differential rotational speed) by controlling (see Patent Document 1). ).

JP 2010-169162 A

  In a conventional lockup clutch slip control device, a deceleration flex lockup control that controls the slip amount of the lockup clutch when the vehicle is decelerating and an acceleration that controls the slip amount of the lockup clutch when the vehicle is accelerating. In any control of the flex lockup control, the hydraulic pressure command value of the torque capacity of the lockup clutch is a positive value. That is, the hydraulic pressure command value is the absolute value of the target rotational speed difference (hereinafter referred to as the target differential rotational speed) of the hydrodynamic power transmission device in both the deceleration flex lockup control and the acceleration flex lockup control. The value corresponds to.

  For this reason, in a conventional lock-up clutch slip control device, the deceleration flex lock-up control in which the target differential rotation speed is set to a negative value is changed to the acceleration flex lock-up control in which the target differential rotation speed is set to a positive value. When shifting, the hydraulic pressure command value temporarily decreases. As a result, when shifting from the deceleration flex lock-up control to the acceleration flex lock-up control, the lock-up clutch is once released, thereby causing a response delay with respect to the hydraulic pressure command value and reducing the response to the acceleration request.

  The present invention has been made in view of the above-described problems, and its purpose is a lock capable of suppressing a decrease in responsiveness to an acceleration request when shifting from a deceleration flex lockup control to an acceleration flex lockup control. An object of the present invention is to provide a slip control device for an up clutch.

  A slip control device for a lockup clutch according to the present invention includes an engine, a transmission, a fluid power transmission device interposed between the engine and the transmission, and a lockup clutch provided in the fluid power transmission device. The slip-up control of the lock-up clutch, which is mounted on a vehicle equipped with the control mechanism, controls the differential rotation speed which is the difference between the rotation speed of the input shaft and the output shaft of the fluid power transmission device by controlling the slip amount of the lock-up clutch The lockup for realizing a target differential rotational speed that is a target value of the differential rotational speed based on an output torque of the engine, a torque capacity of the fluid power transmission device, and an inertia torque of the engine A target hydraulic pressure command value for the clutch is sequentially calculated to control the slip amount of the lockup clutch when the vehicle is decelerating. When the acceleration request is received while the deceleration flex lockup control is being performed, the target hydraulic pressure command value of the lockup clutch is held at the target hydraulic pressure command value when the deceleration flex lockup control is being performed. The holding of the target hydraulic pressure command value is released when the sequentially calculated target hydraulic pressure command value exceeds the held target hydraulic pressure command value.

  According to the slip control device for a lockup clutch according to the present invention, the target differential rotational speed of the fluid power transmission device changes from a negative value to a positive value when shifting from the deceleration flexlockup control to the acceleration flexlockup control. Since a drop in the engagement hydraulic pressure of the lockup clutch due to turning can be avoided, it is possible to suppress a decrease in responsiveness to the acceleration request when shifting from the deceleration flexlockup control to the acceleration flexlockup control.

FIG. 1 is a schematic diagram showing a configuration of a vehicle to which a slip-up control device for a lock-up clutch according to an embodiment of the present invention is applied. FIG. 2 is a flowchart showing the flow of slip control processing according to an embodiment of the present invention. FIG. 3 is a timing chart for explaining a conventional slip control process and a slip control process according to an embodiment of the present invention. FIG. 4 is a diagram for explaining the effect of the slip control process according to the conventional and one embodiment of the present invention.

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

[Vehicle configuration]
First, a configuration of a vehicle to which a slip 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 diagram showing a configuration of a vehicle to which a slip-up control device for a lock-up clutch according to an embodiment of the present invention is applied. As shown in FIG. 1, a vehicle 1 to which a lockup clutch slip control apparatus according to an embodiment of the present invention is applied mainly includes an engine 2, a transmission 3, a torque converter 4, and a lockup clutch 5. As an element.

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. Incidentally, each numeral n _e, T _e in the figure, the engine 2 rpm (hereinafter, engine speed) Represents and output torque.

The transmission 3 shifts the output torque T _t that is the sum of the output torque (torque capacity) T _c of the torque converter 4 and the output torque (torque capacity) T _lu of the lockup clutch 5, and then shifts the output torque to the drive wheels (not shown). introduce. Examples of the transmission 3 include an automatic transmission (AT) and a continuously variable transmission (CVT). Reference numeral n _t in the drawing represents the turbine speed is the rotational speed of the input shaft of the transmission 3 (output shaft of the torque converter 4).

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. A fluid power transmission device that transmits power through a fluid. In the present embodiment, the torque converter 4 is disposed between the engine 2 and the transmission 3, but a fluid power transmission device such as a fluid coupling may be disposed instead of the torque converter 4. In addition, the symbol _{Te 1} in the figure 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 by its complete engagement, and disables the fluid power transmission function of the torque converter 4 by the pump impeller 4a and the turbine impeller 4b. It is something to be made. The lock-up clutch 5 is configured to be controlled between a disengaged state, a slip-engaged state (half-engaged state), and a fully-engaged state by control of the lock-up clutch by the slip control device. Has been. Note that the symbol _Te2 in the figure represents the input torque of the lockup clutch 5.

[Configuration of slip-up clutch slip control device]
Next, with reference to FIG. 1, the structure of the slip control apparatus of the lockup clutch which is one Embodiment of this invention is demonstrated.

  As shown in FIG. 1, a slip-up control device 10 (hereinafter abbreviated as control device 10) for a lock-up clutch according to an embodiment of the present invention is configured by an information processing device such as an ECU (Electronic Control Unit). An arithmetic processing device such as a CPU (Central Processing Unit) inside the processing device executes various processes by executing computer programs stored in the storage unit.

  Specifically, the control device 10 controls the difference between the rotational speeds of the input shaft and the output shaft of the torque converter 4 (hereinafter referred to as differential rotational speed) by controlling the slip amount of the lockup clutch 5. Specifically, the control device 10 controls the deceleration flex lockup control that controls the differential rotation speed of the torque converter 4 by controlling the slip amount of the lockup clutch when the vehicle 1 is decelerating, and the vehicle 1 is accelerating. Accelerated flex lockup control for controlling the differential rotation speed of the torque converter 4 is executed by controlling the slip amount of the lockup clutch at a certain time.

  Further, an accelerator opening sensor 11 is connected to the control device 10, and an electric signal indicating the opening of the accelerator pedal of the vehicle 1 detected by the accelerator opening sensor 11 is input to the control device 10. ing.

  The control device 10 having such a configuration suppresses a decrease in responsiveness to an acceleration request when shifting from the deceleration flex lockup control to the acceleration flex lockup control by executing the slip control process shown below. To do. Hereinafter, with reference to FIG. 2 to FIG. 4, the operation of the control device 10 when executing the slip control process according to the embodiment of the present invention will be described.

[Slip control processing]
FIG. 2 is a flowchart showing the flow of slip control processing according to an embodiment of the present invention. FIG. 3 is a timing chart for explaining a conventional slip control process and a slip control process according to an embodiment of the present invention. FIG. 4 is a diagram for explaining the effect of the slip control process according to the conventional and one embodiment of the present invention.

  The flowchart shown in FIG. 2 starts at the timing when the deceleration flex lockup control is started, and the slip control process proceeds to the process of step S1. This slip control process is repeatedly executed at predetermined control cycles while the deceleration flex lockup control is being performed.

  In the process of step S1, the control device 10 determines whether or not the accelerator pedal is operated based on the output signal from the accelerator opening sensor 11. As a result of the determination, when the accelerator pedal is operated (step S1: Yes), the control device 10 is instructed to shift to the acceleration flex lockup control or the complete lockup control in which the lockup clutch 5 is completely engaged. Judgment is made, and the slip control process proceeds to the process of step S2. On the other hand, when the accelerator pedal is not operated (step S1: No), the control device 10 ends a series of slip control processes.

In the process of step S2, the control device 10 uses the target hydraulic pressure command value u (indicated pressure) corresponding to the target value of the torque capacity _Tlu of the lockup clutch 5 for realizing the target value of the differential rotation speed of the torque converter 4. Is calculated. Specifically, the target hydraulic pressure command value u is shown below using the output torque _Te and rotation speed n _e of the engine 2, the inertia torque I _e of the engine 2, and the torque capacity T _c of the torque converter 4. It is expressed as Equation (1). Therefore, the control unit 10, a time differential value of the rotational speed n _e of the engine 2 is set as the target angular acceleration, calculates the torque capacity T _c of the torque converter 4 as torque capacity obtained from the speed ratio, the formula (1) Is used to calculate the target oil pressure command value u. If the response delay of the torque capacity _Tc of the torque converter 4 is the first order delay of the time constant T, the target hydraulic pressure command value u changes as shown in the following formula (2) with respect to the time t. Here, C in Expression (2) represents a static capacity coefficient of the torque converter 4 obtained by experiments. Therefore, when considering the response delay of the torque capacity _Tc of the torque converter 4, the target hydraulic pressure command value u may be calculated using Equation (2). Thereby, the process of step S2 is completed and the slip control process proceeds to the process of step S3.

  In the process of step S3, the control device 10 determines whether the target hydraulic pressure command value u (indicated pressure) calculated in the process of step S2 is smaller than the target hydraulic pressure command value u (previous value) calculated in the previous slip control process. Determine whether or not. As a result of the determination, when the target hydraulic pressure command value u calculated in the process of step S2 is smaller than the target hydraulic pressure command value u in the previous slip control process (step S3: Yes), the control device 10 performs the slip control process in step S5. Proceed to processing. On the other hand, when the target hydraulic pressure command value u calculated in the processing of step S2 is not smaller than the target hydraulic pressure command value u in the previous slip control processing (step S3: No), the control device 10 performs the slip control processing in step S4. Proceed to the process.

  In the process of step S4, the control device 10 updates the target hydraulic pressure command value u (indicated pressure) to the target hydraulic pressure command value u calculated in the process of step S2. Thereby, the process of step S4 is completed and a series of slip control processes are complete | finished.

  In the process of step S5, the control device 10 holds the target hydraulic pressure command value u (indicated pressure) at the target hydraulic pressure command value u in the previous slip control process, and starts a timing process by a timer for measuring a predetermined time. To do. Thereby, the process of step S5 is completed and the slip control process proceeds to the process of step S6.

  In the process of step S6, the control device 10 determines whether or not a predetermined time has elapsed since holding the target hydraulic pressure command value u based on the count value of the timer. As a result of the determination, when a predetermined time has elapsed since the target hydraulic pressure command value u was held (step S6: Yes), the control device 10 advances the slip control process to the process of step S7. On the other hand, when the predetermined time has not elapsed since the target hydraulic pressure command value u was held (step S6: No), the control device 10 returns the slip control process to the process of step S2.

  In the process of step S7, the control device 10 decreases the target hydraulic pressure command value u by a predetermined value so that the target hydraulic pressure command value u decreases with a predetermined inclination. Thereby, the process of step S7 is completed and the slip control process proceeds to the process of step S8.

  In the process of step S8, the control device 10 calculates the target hydraulic pressure command value u (indicated pressure) by the same process as the process of step S2. Thereby, the process of step S8 is completed and the slip control process proceeds to the process of step S9.

  In the process of step S9, the control device 10 determines whether or not the target hydraulic pressure command value u decreased in the process of step S7 is larger than the target hydraulic pressure command value u calculated in the process of step S8. As a result of the determination, when the target hydraulic pressure command value u decreased in the process of step S7 is larger than the target hydraulic pressure command value u calculated in the process of step S8 (step S9: Yes), the control device 10 performs the slip control process. The process proceeds to S10. On the other hand, when the target hydraulic pressure command value u decreased in the process of step S7 is not larger than the target hydraulic pressure command value u calculated in the process of step S8 (step S9: No), the control device 10 performs the slip control process. The process proceeds to step S11.

  In the process of step S10, the control device 10 determines whether or not the target hydraulic pressure command value u decreased in the process of step S7 is less than or equal to the lower limit value. As a result of the determination, when the target hydraulic pressure command value u decreased in the process of step S7 is not more than the lower limit value (step S10: Yes), the control device 10 ends the series of slip control processes. On the other hand, when the target hydraulic pressure command value u decreased in the process of step S7 is larger than the lower limit value (step S10: No), the control device 10 returns the slip control process to the process of step S7.

  In the process of step S11, the control device 10 calculates the target hydraulic pressure command value u in the process of step S8 until the operation amount of the accelerator pedal becomes zero (accelerator OFF) based on the output signal of the accelerator opening sensor 11. The target hydraulic pressure command value u is updated. Thereby, the process of step S11 is completed and a series of slip control processes are complete | finished.

  In the conventional slip control process, as shown in FIG. 3 (I), the torque from the deceleration flex lock-up control in which the target differential rotational speed of the torque converter 4 is negative according to the increase in the accelerator opening (time t = t1). When shifting to the acceleration flex-lock-up control in which the target differential rotation speed of the converter 4 is positive, the hydraulic pressure command value (lock-up command pressure) of the lock-up clutch 5 temporarily decreases (FIGS. 3D and 4A). )reference). For this reason, once the lockup clutch 5 is released, a response delay with respect to the hydraulic pressure command value occurs, and the response to the acceleration request decreases. As a result, engine speed blow and torque shock occur (see FIGS. 3B and 3C).

  On the other hand, in the slip control process which is one embodiment of the present invention, as shown in FIG. 3 (II), the target differential rotation speed of the torque converter 4 according to the increase in the accelerator opening (time t = t1). Is shifted from the deceleration flex lockup control in which the target differential rotation speed of the torque converter 4 is positive to the acceleration flex lockup control in which the torque converter 4 is positive, the control device 10 determines the hydraulic pressure command value (lockup command pressure) of the lockup clutch 5. ) Is maintained so that the hydraulic pressure command value of the lockup clutch 5 is not lowered (see FIGS. 3D and 4B), and the hydraulic pressure command value of the lockup clutch 5 is lowered after a predetermined time has elapsed. ing. For this reason, it is possible to prevent the engine speed from being blown or the occurrence of a torque shock without releasing the lockup clutch 5 (see FIGS. 3B and 3C).

  As mentioned above, although the embodiment to which the invention made by the present inventors was applied has been described, the present invention is not limited by the description and the drawings that constitute 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 this 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 device 11 Accelerator opening sensor

Claims (1)

An engine, a transmission, a fluid-type power transmission device interposed between the engine and the transmission, and a slip-up of the lock-up clutch mounted on a vehicle including a lock-up clutch provided in the fluid-type power transmission device A slip control device for a lock-up clutch that controls a differential rotational speed that is a difference in rotational speed between an input shaft and an output shaft of the fluid-type power transmission device by controlling an amount;
The target hydraulic pressure command of the lockup clutch for realizing the target differential rotational speed that is the target value of the differential rotational speed based on the output torque of the engine, the torque capacity of the fluid power transmission device, and the inertia torque of the engine When the acceleration request is received when the deceleration flex lockup control is executed to calculate the value sequentially and control the slip amount of the lockup clutch when the vehicle is decelerating, the deceleration flexlockup control is performed. The target hydraulic pressure command value of the lock-up clutch is held in the target hydraulic pressure command value at the time of execution, and when the sequentially calculated target hydraulic pressure command value exceeds the held target hydraulic pressure command value, the target hydraulic pressure command value A slip control device for a lockup clutch, wherein the holding of the lock is released.

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