JP2016156415A - Slip control device of lockup clutch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a slip control device of a lockup clutch which can control an actual slip amount of the lockup clutch to a target slip amount with favorable responsiveness to a change of the output torque of an engine accompanied by an operation of an accelerator pedal of a driver.SOLUTION: A slip control device 10 of a lockup clutch does not calculate a hydraulic pressure command value u of a torque capacity of the lockup clutch by using estimated engine torque Tereal, but calculates the hydraulic pressure command value u of the torque capacity of the lockup clutch by using virtual engine torque Te_cont which is calculated on the basis of a difference between target engine torque Tetgt and the estimated engine torque Tereal. By this constitution, an actual slip amount of the lockup clutch can be controlled to a target slip amount with favorable responsiveness to a change of the output torque of an engine accompanied by an operation of an accelerator pedal of a driver.SELECTED DRAWING: Figure 2

Description

  The present invention controls the number of rotations of the input shaft and the output shaft of the fluid power transmission device by controlling the slip amount of a lockup clutch provided in the fluid power transmission device that transmits the output torque of the engine to the transmission. The present invention relates to a slip control device for a lock-up clutch that controls a difference.

  In general, a vehicle equipped with a fluid power transmission device such as a torque converter or a fluid coupling that transmits engine output torque to a transmission reduces the fluid loss of torque in the fluid power transmission device and improves fuel efficiency. For this purpose, a lock-up clutch is provided. The lockup clutch is arranged in parallel with the fluid power transmission device, and directly connects the engine and the transmission when fully engaged. However, when the engine and the transmission are directly connected by a lock-up clutch at low vehicle speeds, drivability deteriorates because torque fluctuations of the engine are directly transmitted to the transmission. For this reason, normally, at low vehicle speeds, by implementing slip control of the lockup clutch that uses the lockup clutch while slipping with the minimum required slip amount, both improvement of fuel efficiency and suppression of deterioration of drivability are achieved. I am doing so.

  By the way, in the conventional lock-up clutch slip control, as shown in Patent Document 1, when the torque request for the engine suddenly changes, the control device determines the hydraulic pressure command value of the torque capacity of the lock-up clutch based on the output torque of the engine. The correction term which compensates for the response delay to is calculated. Then, the control device outputs the sum of the control amount calculated based on the difference between the actual slip amount and the target slip amount and the correction term as a hydraulic pressure command value for the torque capacity of the lockup clutch.

JP 2014-111977 (paragraphs 0039-0043)

  However, since the correction term is calculated based on the output torque of the engine, the target slip amount can be made closer to the actual slip amount compared to when the control amount is not corrected. There is a dead time until the torque capacity reaches the torque capacity corresponding to the hydraulic pressure command value. For this reason, according to the conventional slip-up clutch slip control, the actual slip amount cannot be matched with the target slip amount until the lock-up clutch has a torque capacity corresponding to the hydraulic pressure command value. There is a possibility that the rotation speed will be blown up. Against this background, it has been expected to provide a technology that can control the actual slip amount of the lockup clutch to the target slip amount with high response to changes in the engine output torque accompanying the driver's operation of the accelerator pedal. .

  The present invention has been made in view of the above problems, and its object is to target the actual slip amount of the lockup clutch with good responsiveness to changes in engine output torque accompanying the driver's operation of the accelerator pedal. An object of the present invention is to provide a slip control device for a lockup clutch that can be controlled to a slip amount.

  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 hydraulic power transmission device provided in the fluid power transmission device. A slip-up control device for a lock-up clutch that is mounted on a vehicle having a lock-up clutch and controls the difference in rotational speed between the input shaft and the output shaft of the fluid-type power transmission device by controlling the slip amount of the lock-up clutch. Then, the virtual engine torque is calculated based on the difference between the target engine torque and the estimated engine torque, and the lockup clutch hydraulic control is set based on the difference between the target slip amount and the actual slip amount of the lockup clutch. The lockup clutch based on the sum of the amount and the correction term calculated from the virtual engine torque And wherein the Rukoto.

  Generally, the target engine torque is fast in response and the estimated engine torque has a small steady deviation. Therefore, the virtual engine torque obtained from the difference between the target engine torque and the estimated engine torque is the case where the actual engine torque changes suddenly. Is also responsive. Therefore, by correcting the hydraulic control amount of the lock-up clutch using the correction term calculated from the virtual engine torque, the lock-up clutch can be responsive to changes in the engine output torque accompanying the driver's accelerator pedal operation. The actual slip amount can be controlled to the target slip amount.

  According to the slip control device for a lockup clutch according to the present invention, the actual slip amount of the lockup clutch is controlled to the target slip amount with high responsiveness to a change in the engine output torque accompanying the driver's operation of the accelerator pedal. be able to.

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 block diagram showing a configuration of a slip control device for a lockup clutch according to an embodiment of the present invention. FIG. 3 is a block diagram showing a configuration of the virtual engine torque calculation unit shown in FIG. FIG. 4 is a conceptual diagram for explaining a method of calculating virtual engine torque. FIG. 5 is a timing chart for explaining the control process of the actual slip rotation speed of the lockup clutch when the accelerator pedal is turned on from the off state. FIG. 6 is a timing chart for explaining the control process of the actual slip rotation speed of the lockup clutch when the accelerator pedal is changed from the on state to the off state. FIG. 7 is a timing chart for explaining the relationship between the value of the transfer function G ₁ (s) and the engine speed. FIG. 8 is a timing chart for explaining the relationship between the value of the transfer function G ₁ (s) and the engine speed. FIG. 9 is a conceptual diagram for explaining a modification of the calculation method of the virtual engine torque. FIG. 10 is a block diagram showing a configuration of a modification of the virtual engine torque calculation unit shown in FIG.

  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. Note that reference numerals ne and Te in the figure represent the rotational speed of the engine 2 (hereinafter referred to as engine rotational speed) and the output torque, 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). The symbol nt in the figure represents the turbine rotational speed that 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 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. Note that the reference symbol Te1 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 controlled by the control device 10 of the lock-up clutch 5 so that its engagement state is controlled between a released state, a slip engagement state (half-engagement state), and a complete engagement state. It is configured. In addition, the code | symbol Te2 in a figure represents the input torque of the lockup clutch 5. FIG.

[Configuration of control device]
Next, with reference to FIG. 2 to FIG. 10, the configuration of the slip control device 10 for the lockup clutch according to the embodiment of the present invention will be described. FIG. 2 is a block diagram showing a configuration of a slip control device for a lockup clutch according to an embodiment of the present invention. FIG. 3 is a block diagram showing a configuration of the virtual engine torque calculation unit 13 shown in FIG. FIG. 4 is a conceptual diagram for explaining a method of calculating virtual engine torque. FIG. 5 is a timing chart for explaining the control process of the actual slip rotation speed of the lockup clutch when the accelerator pedal is turned on from the off state.

FIG. 6 is a timing chart for explaining the control process of the actual slip rotation speed of the lockup clutch when the accelerator pedal is changed from the on state to the off state. FIG. 7 is a timing chart for explaining the relationship between the value of the transfer function G ₁ (s) and the engine speed. FIG. 8 is a timing chart for explaining the relationship between the value of the transfer function G ₁ (s) and the engine speed. FIG. 9 is a conceptual diagram for explaining a modification of the calculation method of the virtual engine torque. FIG. 10 is a block diagram showing a configuration of a modification of the virtual engine torque calculation unit 13 shown in FIG.

  As shown in FIG. 2, the slip control device 10 for a lock-up clutch according to an embodiment of the present invention includes a difference unit 11, a gain multiplication unit 12, a virtual engine torque calculation unit 13, a transfer function multiplication unit 14, and an adder. 15 is provided.

  The differentiator 11 calculates the target slip rotational speed (target slip amount) r of the lockup clutch 5 and the model / actual slip rotational speed nslp (actual slip amount) output from the plant model or actual machine (plant model / actual machine) 21. The difference e (= r−nslp) is calculated, and an electric signal indicating the calculated difference e is output to the gain multiplier 12.

  The gain multiplication unit 12 multiplies the difference e output from the difference unit 11 by the gain K (s), and outputs an electrical signal indicating the multiplication value K (s) * e to the adder 15. The multiplication value K (s) * e corresponds to the hydraulic control amount of the lockup clutch 5 set based on the difference e between the target slip rotation speed r and the model / actual slip rotation speed nslp.

  The virtual engine torque calculation unit 13 calculates a virtual engine torque Te_cont for correcting the multiplication value K (s) * e output from the gain multiplication unit 12, and transmits an electric signal indicating the calculated virtual engine torque Te_cont. The result is output to the function multiplication unit 14. Specifically, as shown in FIG. 3, the virtual engine torque calculation unit 13 includes a difference unit 131, a low-pass filter 132, and a difference unit 133.

  The difference unit 131 calculates a difference between the target engine torque Tetgt and the estimated engine torque Tereal, and outputs an electrical signal indicating the calculated difference to the low-pass filter 132.

  As shown in FIG. 4, the low-pass filter 132 mainly uses the target engine torque Tetgt (line L1) having a good response in the transient state, and mainly uses the estimated engine torque Tereal (line L2) having a small steady-state deviation in the steady state. The engine torque amount to be subtracted from the target engine torque Tetgt is calculated so that the virtual engine torque Te_cont (line L3) is calculated, and an electric signal indicating the calculated engine torque amount is output to the differentiator 133.

  The subtractor 133 calculates a value obtained by subtracting the engine torque amount output from the low-pass filter 132 from the target engine torque Tetgt as a virtual engine torque Te_cont, and an electric signal indicating the calculated virtual engine torque Te_cont is transferred to the transfer function multiplier 14. Output to.

The transfer function multiplication unit 14 calculates a value obtained by multiplying the virtual engine torque Te_cont output from the virtual engine torque calculation unit 13 by the transfer function G ₁ (s), and an electric signal indicating the multiplication value G ₁ (s) * Te_cont. Is output to the adder 15. The multiplication value G ₁ (s) * Te_cont corresponds to a correction term calculated from the virtual engine torque Te_cont.

The adder 15 calculates the sum of the multiplication value K (s) * e output from the gain multiplication unit 12 and the multiplication value G ₁ (s) * Te_cont output from the transfer function multiplication unit 14 as the torque of the lockup clutch 5. It outputs to the hydraulic control device of the lockup clutch 5 as a hydraulic pressure command value u of capacity. Specifically, the hydraulic pressure command value u is expressed as the following formula (1).

  As is apparent from the above description, the lock control device 10 for the lockup clutch according to the embodiment of the present invention calculates the hydraulic pressure command value u for the torque capacity of the lockup clutch 5 using the estimated engine torque Tereal. Instead, the hydraulic pressure command value u of the torque capacity of the lockup clutch 5 is calculated using the virtual engine torque Te_cont calculated based on the difference between the target engine torque Tetgt and the estimated engine torque Tereal.

  Here, since the target engine torque Tetgt is fast in response and the estimated engine torque Tereal has a small steady deviation, the virtual engine torque Te_cont calculated based on the difference between the target engine torque Tetgt and the estimated engine torque Tereal is the actual engine Responsiveness is good even when the torque changes suddenly. Therefore, by calculating the hydraulic pressure command value u for the torque capacity of the lockup clutch 5 using the virtual engine torque Te_cont, the torque of the lockup clutch 5 can be put out. As a result, the model / actual slip rotation speed nslp of the lockup clutch 5 can be controlled to the target slip rotation speed r with good responsiveness to changes in the engine output torque accompanying the driver's operation of the accelerator pedal.

  Specifically, as shown in FIG. 5, when the accelerator pedal changes from the off state to the on state (time t = t1), the hydraulic pressure command value u for the torque capacity of the lockup clutch 5 using the virtual engine torque Te_cont. Is controlled (the solid line in the figure) is faster than the model of the lockup clutch 5 when the hydraulic command value u of the torque capacity of the lockup clutch 5 is controlled using the estimated engine torque Tereal (the broken line in the figure). / The actual slip rotation speed nslp can be controlled to the target slip rotation speed r.

  Specifically, as shown in FIG. 5B, the virtual engine torque Te_cont (line L12) increases faster than the estimated engine torque Tereal (line L13), so as shown in FIGS. 5C and 5D. When the virtual engine torque Te_cont is used (lines L14 and L16), the hydraulic pressure supplied to the lockup clutch 5 increases faster than when the estimated engine torque Tereal is used (lines L15 and L17). As a result, as shown in FIG. 5 (e), when the virtual engine torque Te_cont is used (line L18), the model / model of the lockup clutch 5 is faster than when the estimated engine torque Tereal is used (line L19). The actual slip rotation speed nslp can be controlled to the target slip rotation speed r (line L20).

  Similarly, as shown in FIG. 6, when the accelerator pedal changes from the on state to the off state (time t = t3), the hydraulic command value u of the torque capacity of the lockup clutch 5 is controlled using the virtual engine torque Te_cont. In the case (solid line in the figure), the model / actuality of the lockup clutch 5 is more quickly obtained than when the hydraulic command value u of the torque capacity of the lockup clutch 5 is controlled using the estimated engine torque Tereal (dashed line in the figure). The slip rotation speed nslp can be controlled to the target slip rotation speed r.

  Specifically, as shown in FIG. 6 (b), the virtual engine torque Te_cont (line L12) decreases faster than the estimated engine torque Tereal (line L13), so as shown in FIGS. 6 (c) and 6 (d). When the virtual engine torque Te_cont is used (lines L14 and L16), the hydraulic pressure supplied to the lockup clutch 5 decreases earlier than when the estimated engine torque Tereal is used (lines L15 and L17). As a result, as shown in FIG. 6 (e), when the virtual engine torque Te_cont is used (line L18), the model / model of the lockup clutch 5 is faster than when the estimated engine torque Tereal is used (line L19). The actual slip rotation speed nslp can be controlled to the target slip rotation speed r (line L20).

As shown in FIGS. 7A and 7B, when the value of the transfer function G ₁ (s) multiplied by the virtual engine torque Te_cont is set to 1, the change in the engine torque can be offset. If the engine torque is reduced by the amount of variation, the engine speed may drop or engine stall may occur. For this reason, as shown in FIGS. 8A and 8B, the correction term calculated from the virtual engine torque Te_cont by setting the value of the transfer function G ₁ (s) to a value smaller than 1 is used as the actual engine. It is desirable to set a value lower than the torque by the variation of the engine torque. Thereby, it can suppress that an engine speed falls or an engine stall occurs.

  In this embodiment, the virtual engine torque Te_cont is calculated mainly using the target engine torque Tetgt having good responsiveness in the transient state and mainly using the estimated engine torque Tereal having a small steady-state deviation in the steady state. In the transient state (phase I) and the steady state (phase III), the virtual engine torque Te_cont (line L3) is matched with the target engine torque Tetgt (line L1) and the estimated engine torque Tereal (line L2), respectively. In the section (phase II) between the transient state and the steady state, the virtual engine torque Te_cont may be continuously changed from the target engine torque Tetgt to the estimated engine torque Tereal.

  In addition, as shown in FIG. 10, the target engine torque Tetgt may be calculated from the accelerator pedal opening or the throttle opening pa. By calculating the target engine torque Tetgt and the virtual engine torque Te_cont from the accelerator pedal opening or the throttle opening pa, which has a quick response, the target slip can be set to the model / actual slip rotation speed nslp with high response even when the engine torque changes suddenly. It is possible to follow the rotational speed r.

  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 Lockup clutch 10 Slip control device of lockup clutch 11 Difference machine 12 Gain multiplication part 13 Virtual engine torque calculation part 14 Transfer function multiplication part 15 Adder

Claims (1)

The lockup is mounted on a vehicle including an engine, a transmission, a fluid power transmission device interposed between the engine and the transmission, and a hydraulic lockup clutch provided in the fluid power transmission device. 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 the fluid-type power transmission device by controlling a slip amount of the clutch,
A virtual engine torque is calculated based on the difference between the target engine torque and the estimated engine torque, and the hydraulic control amount of the lockup clutch set based on the difference between the target slip amount of the lockup clutch and the actual slip amount A slip-up control device for a lock-up clutch, wherein the lock-up clutch hydraulic pressure is controlled based on a sum of a correction term calculated from a virtual engine torque.

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