JP2002286055A - Learning method of torque point of clutch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable learning of torque point in a wet multiple disc clutch. SOLUTION: A fluid coupling and a wet friction clutch are arranged in series on the way from an engine to a transmission. The hydraulic actuation pressure supplied to the wet friction clutch is varied in accordance with the duty pulse output from ECU, thereby the connection/disconnection condition of the clutch is controlled in the drive force transmission device of a vehicle. When learning the torque point transferring a specified torque at first when the clutch is connected from the disconnected condition, in the ECU, the clutch is gradually disconnected from the connected condition while detecting the input side revolution number Nt and the engine revolution number Ne and in the process, when the difference between the engine revolution number Ne and the input side revolution number Nt becomes smaller than a required revolution number Nm, the ECU learns the duty ratio Dm as a torque point, at the time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for learning a torque point of a clutch, and more particularly to a learning method for suitably learning a torque point when a wet friction clutch is used in a power transmission system of a vehicle.

[0002]

2. Description of the Related Art In a power transmission device for a vehicle, a fluid coupling (including a torque converter) and a wet friction clutch are provided in series in a power transmission path from an engine to a transmission. Some automatically connect and disconnect. In this case, if the gear-in operation is performed while the vehicle is stopped, the clutch is automatically connected thereafter, and creep occurs. This is the same as a normal AT car.

If the connection of the clutch is too early, a clutch connection shock (a so-called garage shock or the like) occurs. If the connection is too late, it takes time from the gear-in operation to the occurrence of creep, and it is not clear when the driver can depress the accelerator (time lag). Big). Therefore, in order to achieve both the clutch connection shock and the reduction of the connection time, control is performed such that the clutch is suddenly brought into contact in a play area until the clutch is started to be engaged, and when the clutch is started to be engaged, the connection speed is switched to slowly engage. ing.

The position at which the clutch starts to be engaged, in other words, the torque transmission start point at which the predetermined torque can be transmitted first is referred to as a torque point, and this torque point is learned by the control unit and used as a point for switching the connection speed. The torque point plays an important role in clutch control. The reason why the torque point is used as the learning value is that the clutch has variations or individual differences due to manufacturing errors and the like, and the torque point differs for each clutch.

[0005]

With respect to such torque point learning, conventionally, in a dry friction clutch, a clutch stroke value for transmitting a predetermined torque is first detected, and the value is learned as a torque point. Was.

However, in the case of a wet friction clutch, the clutch plate always slides in the oil, and torque transmission is achieved by pressing the plates together with the clutch piston. Although the clutch piston makes a stroke, the stroke amount is very small (for example, about 2 mm). Therefore, a method of detecting the stroke of the clutch piston and setting it as a learning value as in the case of the dry type cannot be adopted.

In a wet friction clutch, a method of detecting a hydraulic pressure applied to a clutch piston may be considered. However, the oil pressure sensor is expensive, and it is difficult to detect the oil pressure for structural reasons. In addition, the hydraulic pulsation is large and there is a problem in the reliability of the detected value itself, and there is also a problem of individual differences that the same torque is not always transmitted to the same hydraulic value. Therefore, this method cannot be adopted.

The present invention has been made in view of the above problems, and an object of the present invention is to enable learning of a torque point in a wet friction clutch.

[0009]

A method of learning a torque point of a clutch according to the present invention comprises a fluid coupling on an upstream side of a power transmission path from an engine to a transmission and a wet friction clutch on a downstream side thereof. Are provided in series, and a fluid pressure supply device for supplying a working fluid pressure to the wet friction clutch is provided, and the fluid pressure supplied from the fluid pressure supply device is changed by the duty of the duty pulse output from the electronic control unit. In the power transmission device for a vehicle, the predetermined torque is first transmitted when the wet friction clutch is connected from the disengaged state in the vehicle power transmission device that changes according to the ratio, thereby controlling the connection / disconnection state of the wet friction clutch. When learning the torque point to be performed to the electronic control unit, the input-side rotation speed of the wet friction clutch,
While detecting the engine speed, the duty ratio is changed to gradually disconnect the wet friction clutch from the contact state, and in the process, the engine speed and the input of the wet friction clutch are changed. When the difference from the rotation speed on the side becomes equal to or less than a predetermined value, the value of the duty ratio at that time is learned as a torque point.

Here, the start condition of the torque point learning is as follows.
It is preferable to include the following conditions: vehicle stop, parking brake operation, foot brake operation, and transmission gear-in.

[0011]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows a vehicle power transmission device according to this embodiment. As illustrated, a transmission T / M is connected to the engine E via a clutch mechanism 1. The clutch mechanism 1 includes a fluid coupling (fluid coupling) 2 and a wet multi-plate clutch 3. The fluid coupling 2 is provided on the upstream side of the power transmission path from the engine E to the transmission T / M, and the wet multi-plate clutch 3 is provided in series on the downstream side. The term “fluid coupling” as used herein is a broad concept including a torque converter, and the present embodiment also uses a torque converter.

The fluid coupling 2 includes a pump 4 connected to the output shaft (crankshaft) of the engine, a turbine 5 opposed to the pump 4 and connected to the input side of the clutch 3, and a fluid coupling between the turbine 5 and the pump 4. And a lock-up clutch 7 for engaging and disengaging the pump 4 and the turbine 5 from each other. The input side of the wet multi-plate clutch 3 is connected to the turbine 5 via the input shaft 3a, the output side is connected to the input shaft 8 of the transmission T / M, and a connection between the fluid coupling 2 and the transmission T / M is provided. It is a matter of connection.

The transmission T / M has an input shaft 8, an output shaft 9 arranged coaxially with the input shaft 8, and a sub shaft 10 arranged parallel to these. The input shaft 8 is provided with an input main gear 11. The output shaft 9 includes a first-speed main gear M1, a second-speed main gear M2, a third-speed main gear M3, a fourth-speed main gear M4,
The reverse main gear MR and the reverse main gear MR are
The speed main gear M6 is fixed. An input auxiliary gear 12 meshing with an input main gear 11 and a first-speed main gear M1
, The second-speed auxiliary gear C2 meshing with the second-speed main gear M2, the third-speed auxiliary gear C3 meshing with the third-speed main gear M3, and the fourth gear meshing with the fourth-speed main gear M4. Secondary gear C4
And a reverse auxiliary gear CR that meshes with the reverse main gear MR via the idle gear IR,
A sixth-speed auxiliary gear C6 meshing with the sixth-speed main gear M6 is supported.

According to the transmission T / M, when the sleeve S / R1 spline-engaged with the hub H / R1 fixed to the output shaft 9 is spline-engaged with the dog DR of the reverse main gear MR, the output shaft 9 is rotated. When the sleeve S / R1 is spline-engaged with the dog D1 of the first-speed main gear M1, the output shaft 9 rotates at the first speed. When the sleeve S / 23 spline-engaged with the hub H / 23 fixed to the output shaft 9 is spline-engaged with the dog D2 of the second-speed main gear M2, the output shaft 9 rotates at a speed equivalent to the second speed, and the sleeve S / 23 rotates. When S / 23 is engaged with the dog D3 of the third speed main gear M3 by spline engagement, the output shaft 9 rotates at the speed equivalent to the third speed.

A hub H / 4 fixed to the output shaft 9
When the sleeve S / 45 meshed with the spline 5 is spline-engaged with the dog D4 of the fourth speed main gear M4, the output shaft 9
When the sleeve S / 45 is spline-engaged with the dog D5 of the input main gear 11, the output shaft 9 rotates at the fifth speed (direct connection). The sleeve S6 spline-engaged with the hub H6 fixed to the sub shaft 10
Is spline-engaged with the dog D6 of the sixth-speed auxiliary gear C6, the output shaft 9 rotates at a speed equivalent to the sixth speed. Each of the sleeves is manually operated by a shift lever in a cab via a shift fork and a shift rod (not shown).

The wet multi-plate clutch 3 has a normal configuration.
That is, although not shown, a plurality of clutch plates are alternately spline-engaged on the input side and the output side in the oil-filled clutch casing, and these clutch plates are pressed against each other by the clutch piston or released. Then, the clutch is connected and disconnected. Referring to FIG. 2, clutch piston 2
The clutch 7 is always urged to the disconnected side by the clutch spring 28, and the clutch 3 is engaged when a hydraulic pressure exceeding this is applied to the clutch piston 27. The clutch engagement force or the clutch torque capacity is increased according to the applied hydraulic pressure.

Next, a description will be given of a hydraulic pressure supply device for supplying operating hydraulic pressure to the wet multi-plate clutch 3. As shown in FIG. 2, the oil in the oil tank 13 is suctioned and discharged by the hydraulic pump OP via the filter 14, and the discharge pressure is adjusted by the relief valve 15, so that a constant line pressure PL is generated. The oil of the line pressure PL is controlled (pressure-reduced) and sent to the clutch 3 by using two valves, a clutch control valve CCV and a clutch solenoid valve CSV. That is, a pilot-operated hydraulic control system is adopted in which the clutch control valve CCV connected to the main hydraulic line is opened and closed according to the pilot hydraulic pressure Pp sent from the clutch solenoid valve CSV. Then, the magnitude of the pilot oil pressure Pp is changed according to the duty ratio D of the duty pulse output from the electronic control unit (hereinafter referred to as ECU) 16.

That is, the clutch solenoid valve CSV is an electromagnetic valve having an electromagnetic solenoid, can be opened and closed in a stepless manner, and is always supplied with the line pressure PL.
Then, the duty pulse output from the ECU 16 is received, and the valve body is opened by an amount corresponding to the duty ratio D. As a result, the clutch solenoid valve CSV outputs the pilot oil pressure Pp corresponding to the duty ratio D.

The clutch control valve CCV is a spool valve that is opened and closed in a stepless manner based on the pilot oil pressure Pp, and is not electronically controlled. That is, the built-in spool is stroked to the open side according to the magnitude of the pilot oil pressure Pp, whereby the line pressure PL is appropriately adjusted and sent to the clutch 3 as the clutch pressure Pc. Thus, as a result, the hydraulic pressure supplied to the clutch 3
6, the duty is controlled.

An accumulator 17 is provided in a path connecting the clutch solenoid valve CSV and the clutch control valve CCV.

FIG. 3 shows a characteristic diagram of the hydraulic pressure supply device. The horizontal axis is the duty ratio D of the duty pulse output from the ECU 16, and more specifically, the on duty ratio indicating the ratio of the solenoid on time in a predetermined control cycle (20 msec in the present embodiment). In this embodiment, when the duty ratio D is 0 (%), the clutch is completely engaged. This is because even when the clutch solenoid valve CSV is not energized at all due to a failure of the electric system or the like (so-called off-stack state), the clutch is connected and the vehicle can be maintained. .

As shown, the larger the duty ratio D, the closer the duty ratio D, and the smaller the duty ratio D, the closer the duty ratio D. As the value of the duty ratio D decreases, the value of the pilot oil pressure Pp output from the clutch control valve CCV increases proportionally, and accordingly, the oil pressure supplied to the clutch, that is, the clutch pressure Pc
And the torque capacity Tc of the clutch 3 tends to increase proportionally. Although the valve opening degree V of the clutch control valve CCV is three positions in the drawing, the spool valve makes a small stroke at an intermediate opening degree (valve opening degree of 0 mm) other than fully open and fully closed, and the clutch pressure Pc is reduced. It can be changed continuously.

Although a control system for the lock-up clutch 7 is also present in this embodiment, the description is omitted here because it is not directly related to the present invention. The configuration of the hydraulic control system is substantially the same as the hydraulic control system of the wet multi-plate clutch 3.

Next, an electronic control unit for electronically controlling the power transmission device will be described with reference to FIG. The aforementioned ECU1
In addition to the clutch solenoid valve CSV, various switches and sensors for electronically controlling the present device are connected to 6. These include an engine speed sensor 18 for detecting the engine speed, a turbine speed sensor 19 for detecting the speed of the input side of the clutch 3, ie, the speed of the turbine 5, the speed of the transmission T / M, and the like. Specifically, a transmission rotation sensor 20 for detecting the number of rotations of the input auxiliary gear 12,
And a vehicle speed sensor 21 for detecting the vehicle speed.
These sensors are also shown in FIG. Also, a parking brake switch 22 for detecting whether the parking brake is operating, a foot brake switch 23 for detecting whether the foot brake is operating, and a gear for detecting the gear position of the transmission. A position sensor 24 is also included.

A knob switch 25 is also connected to the ECU 16. That is, in this embodiment, in order to detect the start time of the shift operation by the driver or to determine the timing of starting the clutch disengagement, the shift knob of the cab shift lever can slightly swing in the shift direction with respect to the lever. , And a knob switch 25 is provided between the lever and the shift knob. When the shift knob swings prior to the operation of the lever during the gear shifting operation by the driver, the knob switch 25 is turned on.
It is turned on, and the clutch is started to be signaled by this. The specific configuration is the same as that shown in Japanese Patent Application Laid-Open No. 11-236931.

The power transmission device according to the present embodiment includes a slope start assist device (HSA; Hill Star
t Aid) is provided, and an HSA switch 26 is provided in the cab for manually turning on / off the device, and the HSA switch 26 is connected to the ECU 16. This HSA
The switch 26 also serves as a trigger switch for starting torque learning according to the present invention.
It doesn't have much meaning in itself.

Next, the operation of the power transmission device according to this embodiment will be described.

In this power transmission device, the power of the engine E is transmitted in the order of the fluid coupling 2, the wet multi-plate clutch 3, and the transmission T / M. The lock-up clutch 7 is always on (contact) during running after starting, and is off only when the vehicle is stopped.
(Cut off). Therefore, the creep of the fluid coupling 2 can be used at the time of starting, and the control can be simplified as compared with a system in which the friction clutch is electronically started and controlled, and the fluid coupling 2 is locked up during traveling, so that loss due to slip can be prevented. . The wet multi-plate clutch 3 is disengaged and connected each time the gear is shifted. This is similar to a normal MT vehicle.

First, the operation at the time of starting the vehicle will be described. Suppose that the driver tries to start while the vehicle is stopped in gear neutral, and then operates the shift lever to the start position.
Then, the shift switch is turned on the shift lever prior to the operation of the lever, so that the knob switch 25 is turned on.
Then, the clutch 3 is disconnected by the signal. Then, by continuously operating the shift lever, the transmission T
/ M is geared into the starting gear, and when this is detected by the gear position sensor 24, the clutch 3 is engaged. This connection stops the turbine 5 from the driving wheel side, so that the pump 4 slides relative to the turbine 5 and a creep force is generated. Therefore, the vehicle starts moving when you release the brake or depress the accelerator.

Next, the operation at the time of shifting while the vehicle is running will be described. It is assumed that while the vehicle is traveling at a predetermined gear, the driver tries to shift and operates the shift lever to the next gear. Then, the shift knob swings prior to the operation of the lever, and the knob switch 25 is turned on, and the clutch 3 is disengaged by this signal. When the shift lever is continuously operated, the transmission T / M is shifted to the next gear position, and when this is detected by the gear position sensor 24, the clutch 3 is engaged. This completes the shift. During this shift, the lock-up clutch 7 remains on, and the engine power is transmitted to the clutch 3 as it is.

By the way, the connection of the clutch 3 is performed at a high speed (rapid connection) from the complete disconnection to the vicinity of the torque point, and at a low speed (slow connection) from the vicinity of the torque point. By switching the connection speed in this manner, it is possible to reduce both connection shock and connection time.

Then, the position where the clutch starts to be connected,
In other words, it is important to first grasp the torque point at which the predetermined torque can be transmitted. This is because the connection speed switching point is determined based on this torque point.

The torque point has individual differences and variations for each clutch, and cannot be uniquely determined. In the present embodiment, as shown in FIG. 3, even when the same duty pulse is applied, the clutch torque capacity diagram is almost shifted as indicated by an arrow. Therefore, it is necessary to learn the torque point for each clutch or each vehicle. In controlling the conventional dry friction clutch, the torque point could be determined by the clutch stroke. However, in a wet multi-plate clutch as in the present invention, there is no concept of a stroke from the beginning, so a similar method cannot be adopted.

Therefore, in the present invention, the value of the duty ratio of the duty pulse output by the ECU 16 itself is used as the torque point learning value. Hereinafter, this will be described in detail.

FIG. 5 is a time chart showing the contents of the torque point learning control according to the present invention. (a) shows the duty pulse output by the ECU 16, (b) shows how the duty ratio D changes, and (c) virtually shows the clutch stroke of the wet multi-plate clutch 3 for easy understanding. (D) shows how the rotation speed of the engine E (engine rotation speed Ne) and the rotation speed of the turbine 5 (turbine rotation speed Nt) change. As shown in (a), the time period of the torque learning control is Δt, and in this embodiment, Δt = 20 (msec)
It is.

First, it is assumed that a predetermined learning condition is satisfied at time t1. This learning condition includes a condition that the vehicle is stopped, the parking brake is operating, and the foot brake is operating. At this time, the duty ratio D = 100 (%), and the clutch is completely disengaged. Therefore, the turbine 5 rotates with the pump 4, and the turbine speed Nt matches the engine speed Ne.

Thereafter, when a predetermined learning start condition is satisfied at time t2, learning is started. The learning start condition includes a condition that the transmission T / M is engaged. First, the duty ratio D is set to 0 (%), and the clutch is completely engaged. As a result, the output side of the clutch is stopped by the brake, the turbine speed Nt becomes zero, and creep occurs. Next, the duty ratio D is relatively increased to the disconnect side, and the start duty D0 is set to 30 (%). This is to shorten the learning time. However, the value of the start duty D0 is determined so that the clutch never reaches the target torque point even if the clutch varies, and approaches the torque point as much as possible. In other words, D = 0 to 30 (%) can be said to be an invalid area (play) in all clutches, and the aim here is to reduce the learning time by connecting such invalid areas at once. .

According to FIG. 3, the duty ratio D starts from 0 (%).
When it reaches 30 (%), the torque capacity still shows a complete value of about 620 (Nm). Therefore, it is advisable to connect such invalid components at once. The start duty D0 is predetermined based on experimental data as shown.

Next, after completing such a large division,
The connection width for each cycle is reduced, and the clutch disconnection speed is extremely reduced. That is, as shown in FIG. 5, the increment of the duty ratio for each cycle is determined by the step duty Ds (in the present embodiment, 0.
048 (%)), and the duty ratio D is increased by Ds for each control.

When the clutch is gradually disengaged, the turbine speed Nt approaches the engine speed Ne. That is, the turbine 5, which is the input side of the clutch, tries to follow the pump 4 being rotated by the engine, and the slip between the pump 4 and the turbine 5 gradually decreases,
The turbine speed Nt gradually approaches the engine speed Ne.

Thus, the difference between these rotational speeds ΔN = Ne−N
When t reaches a predetermined value Nm, the ECU 16 learns the value of the duty ratio D at this time as a torque point learning value Dm. In the present embodiment, Nm = 300 (rpm). More specifically, the ECU 16 increases the duty ratio D by the step duty Ds and gradually disengages the clutch. ΔN = Ne−
When Nt falls below the predetermined value Nm, the ECU 1
6. The value of the duty ratio D of the duty pulse transmitted by itself is stored in the memory in the ECU 16 as the torque point learning value Dm.

When the storage of the torque point learning value Dm is completed, the learning is substantially completed, and thereafter, the clutch is completely released and all the learning control (learning mode) is completed.

Referring to FIG. 3, for example, duty ratio D =
Assuming that the rotation difference ΔN becomes equal to or less than the predetermined value Nm for the first time when it reaches 50 (%), the torque capacity of the clutch 3 at this time is Tcm = about 200 (Nm), which is the torque point. Even if the torque capacity diagram deviates due to variations in the clutch or the like, since the torque capacity and the rotation difference ΔN have a unique relationship, if the duty ratio D indicating the same rotation difference Nm is detected, the same torque capacity Tcm will be obtained. Points can be detected. As a result, a constant torque point can always be detected and learned regardless of the individual difference of the clutch.

As described above, according to the present invention, it is possible to suitably learn the torque point even in the wet type multi-plate clutch.
The torque points different for each clutch can be accurately grasped and used for various clutch controls such as connection speed switching. Then, the variation of the clutch and its control device and the individual difference are absorbed, and the wet multi-plate clutch can be connected with the same feeling in any vehicle.

By the way, the clutch connection control after learning the torque point as described above is as follows. That is, from the clutch disengaged state with the duty ratio D = 100 (%), the duty ratio of a value slightly larger (greater value) than the torque point learning value Dm is initially applied to the clutch solenoid valve CSV. This is called one-shot control. As a result, the ineffective portion of the clutch is suddenly brought into contact, and the connection time can be reduced. After waiting a predetermined time (for example, 0.5 sec) in this state, the duty ratio is reduced by a small step duty. Thereby, the clutch is loosely connected, and the clutch connection shock is prevented.

Next, the contents of the torque point learning control will be described in more detail with reference to FIG. FIG. 6 is a state transition diagram showing the transition of the clutch control phase.

The torque point learning can be arbitrarily performed according to the driver's intention. When the driver wants to learn, the driver first operates the shift lever to neutral (N). In this device, the clutch is normally disconnected when the gear is neutral and engaged when the gear is engaged in the normal control of the clutch. Therefore, the clutch is automatically disengaged by operating the shift lever to N.

This state is called a clutch complete phase 101 shown in FIG. That is, at this time, the vehicle stop duty D0 = 100 (%) is output from the ECU 16, and the clutch is completely disengaged.

Next, when a predetermined condition is satisfied from this state, the learning mode is entered, and the process proceeds to the learning complete phase 102. The transition condition T1 at this time is that the vehicle is stopped (vehicle speed = 0 km / h). The transmission T / M is in the neutral state.
rpm, idle speed of this embodiment = 600 rpm) The parking brake operation and the foot brake operation are all satisfied, and the HSA switch 26 is turned on in this state. Also in this phase, the clutch is completely released, that is, the duty D0 = 100 (%) is continuously output from the ECU 16 to maintain the complete clutch release. Since the foot brake is depressed according to the condition (1), the accelerator is in the released state, and the normal condition is satisfied unless the engine is performing an extremely high first idling operation. Other conditions can be appropriately added as the transition condition T1.

The establishment of the learning condition at time t1 in FIG. 5 means that the above-mentioned transition condition T1 has just been established. That is, the clutch is completely disconnected by the clutch complete phase 101 before time t1, and the clutch is completely completed by the learning complete phase 102 after time t1.

Next, when the transition condition T2 is satisfied from the learning complete phase 102, the processing shifts to the learning loose disconnection phase 103. The transition condition T2 is that the transmission T / M has been shifted into second gear. That is, when the driver performs the second gear change operation from the state of the learning complete phase 102, the learning loose phase 1
Shift to 03, the clutch is automatically engaged and then released. The shift operation to the second speed is a signal to start learning, so to speak. The transition condition T2 can be changed to another condition or added to another condition as appropriate. The second speed is an example, and the point is that the output side of the clutch only needs to be stopped by the brake, so that the gear may be at any speed. However, it is a condition that the gear is engaged in one of the gears. In this embodiment, 2
Since a vehicle (a truck or the like) is frequently used for quick start, learning is also performed at the second speed because it is close to actual.

The satisfaction of the learning start condition at time t2 in FIG. 5 means that the transition condition T2 has just been satisfied. As shown in FIG. 5, in the learning loose disconnection phase 103, first, D = 0 (%) is output from the ECU 16 to completely engage the clutch, and then the start duty D0 = 30 (%) is output to output the clutch. , The duty ratio D is increased by a step duty Ds = 0.048 (%) at each control, and the clutch is gradually disengaged.

Note that the clutch complete connection is not always necessary, and the start duty D0 may be output immediately and the clutch loosening may be started from here. Alternatively, after D = 0 (%) is output, the start duty D0 may be output after holding it for a certain period of time. This is because there is a time delay until the clutch is actually completed.

When the transition condition T3 is satisfied from the learning loosening phase 103, the processing shifts to the learning stop phase 104.
The transition condition T3 is that the rotation difference ΔN = Ne−Nt between the engine speed Ne and the turbine speed Nt becomes equal to or less than a predetermined value Nm = 300 (rpm). In the learning stop phase 104, the duty ratio D when the condition is satisfied is held for a fixed time (a plurality of cycles, for example, 1 second), and the clutch is held at the current state. After that, the ECU 16 temporarily determines the value of the duty ratio D.
Then, it is determined whether or not this value is a normal value as a learning value by comparing with a predetermined condition. If normal, the value is updated and learned as a new learning value Dm. At this time, the old learning value already stored is deleted. The reason for taking in the duty ratio D after holding it for a certain period of time is to consider the influence of noise and the like.

Note that conditions other than the transition condition T3 can be appropriately adopted. The condition is that if the engine idling speed is 600 rpm, the turbine speed Nt is １ ／ of the engine speed Ne.
This can be rephrased as follows. The condition may be replaced by the condition that the engine speed Ne drops from the idle speed below a predetermined speed. That is, if the turbine speed Nt drops due to clutch completeness, the engine speed Ne is dragged. Because the engine speed Ne also drops from the idle speed, the torque learning point may be determined by checking the degree of decrease in the engine speed Ne. For example, the drop amount of the engine speed Ne is reduced to 50 (rpm). Set.

Next, when the transition condition T4 is satisfied from the learning stop phase 104, the process proceeds to the learning end phase 105. The transition condition T4 is a condition that the learning of the torque point learning value Dm has been completed normally, and the vehicle has started to move (vehicle speed ≠ 0 km / h). Is not around the idle speed (Ne <300 rpm or> 800 rpm). One of the conditions is satisfied, such as the parking brake has been deactivated and the foot brake has been deactivated. In particular~
Means that it is not suitable for learning execution,
When these conditions are satisfied, the learning complete phase 102
Even in the learning break phase 103, the process proceeds to the learning end phase 105. That is, the transition conditions T6 and T5 from the learning complete phase 102 and the learning loose phase 103 to the learning end phase 105 are equal to T4. There are various other conditions that are inappropriate for such learning execution.

In the learning end phase 105, the ECU 16
Output a duty D0 = 100 (%) to complete the clutch. The output satisfies the transition condition T7, exits the learning mode, returns to the normal control, and reaches the control stop mode 106. In the control stop mode 106, the duty D0 = 100 (%) is maintained to maintain the clutch complete, but the situation is different from the normal state where the clutch is disengaged while the gear is in the second speed. However, the driver returns to normal control by setting the gear to neutral.

The details of the torque point learning control have been described above.
Next, the contents of the normal clutch engagement control and the correction of the control value based on the torque point learning value thus obtained will be described.

FIG. 7 is a time chart showing the contents of the clutch engagement control. The horizontal axis represents time t, and the vertical axis represents the duty ratio D output from the ECU 16. A solid line is a diagram as a base before correction, and a broken line is a diagram after correction of two patterns (1, 2 after correction).

First, the contents of the clutch engagement control will be described with reference to the base. The one-shot connection duty, that is, the start duty Dst0, which is output first from the complete state (D = 100 (%)), the end duty Ded0 that determines the end of the clutch loose connection, and the step duty Ds0 that is a decrease width for each control cycle are set. Is selected from a map stored in the ECU 16 in advance. The map is created in advance based on a test or the like so that each optimal value reflecting the driving state of the vehicle and the like is obtained. The base value of the torque point learning value is predetermined as Dtb and stored in the ECU 16.

In the clutch engagement control in this case, the start duty Dst0 is first output from the complete disconnection state (D = 100 (%)), and after one-shot engagement, the duty ratio is reduced by a step duty Ds0, and the duty ratio is reduced by half. Perform loose connection with the clutch.
Then, when the end duty Ded0 is reached, D = 0 (%) is output and the clutch is completely engaged. As shown in the figure, the start duty Dst0 is a value slightly off (closer to) the base value Dtb of the torque point learning value.

By the way, it is assumed that the torque point learning value is updated to Dlt1 smaller than the base value Dtb by executing the torque point learning (1 after correction). Then, the start duty and the end duty are corrected as described below, and the duty diagram is obtained by translating the base diagram parallel to the tangent side as shown by the broken line 1 after the correction.

That is, first, the difference ΔDse = Dst0−Ded0 between the start duty Dst0 and the end duty Ded0 that defines the half-clutch contact range, and the difference A = Dtb−D between the base value Dtb and the update value Dlt1 of the torque point learning value.
lt1 (> 0) is calculated. Then, the corrected start duty Dst1 is calculated based on the equation Dst1 = Dst0-A, and the corrected end duty Ded1 is calculated based on the equation Ded1 = Dst1-ΔDse. The clutch engagement control after the correction 1 includes the start duty Dst1 and the end duty Ded1.
And will be executed using Similarly, in the subsequent clutch engagement control, the base value of the start duty and the end duty obtained from the map for each control is corrected based on the difference A between the base value Dtb of the torque point learning value and the update value Dlt1. Used from.

The corrected value 1 is an updated value Dlt of the torque point learning value.
1 is an example in which it becomes smaller than the base value Dtb, but after correction 2 is an example in which the updated value Dlt2 becomes larger than the base value Dtb, and the diagram also moves to the side where the duty is larger (disconnected) with respect to the base. .

Similarly, in the case of 2 after this correction, the difference ΔDse between the start duty Dst0 and the end duty Ded0 is similarly calculated.
= Dst0-Ded0, and difference B = Dtb-Dlt2 between base value Dtb of torque point learning value and update value Dlt2.
(<0) is calculated, the corrected start duty is calculated based on the equation Dst2 = Dst0−B, and the corrected end duty is calculated based on the equation Ded2 = Dst2-ΔDse. The clutch engagement control after the correction 2 is based on the start duty Dst2 and the end duty De.
This is executed using d2. The subsequent clutch engagement control also
The base value of the start duty and the end duty obtained from the map for each control cycle is used after being corrected based on the difference B between the base value Dtb of the torque point learning value and the update value Dlt2.

The embodiments of the present invention are not limited to those described above. The wet friction clutch according to the present invention is a multi-disc type in the above embodiment, but may be a single-disc type, for example.
The fluid pressure referred to in the present invention is a hydraulic pressure in the above embodiment, but may be another fluid pressure such as pneumatic pressure. Although the transmission according to the present invention is a constant-mesh manual transmission in the above embodiment, it may be a constant-mesh automatic transmission or a planetary gear-type automatic transmission such as an AT car. The engine is not limited to diesel or gasoline. The numerical values shown in the above embodiment can be changed as appropriate.

[0068]

As described above, according to the present invention, an excellent effect that the torque point can be suitably learned even in a wet multi-plate clutch is exhibited.

[Brief description of the drawings]

FIG. 1 is a skeleton diagram showing a vehicle power transmission device according to an embodiment of the present invention.

FIG. 2 is a hydraulic circuit diagram showing a hydraulic supply device according to an embodiment of the present invention.

FIG. 3 is a characteristic diagram of the hydraulic pressure supply device according to the embodiment of the present invention.

FIG. 4 is a configuration diagram showing an electronic control device according to the embodiment of the present invention.

FIG. 5 is a time chart showing the contents of torque point learning control according to the embodiment of the present invention.

FIG. 6 is a state transition diagram showing a transition of a clutch control phase according to the embodiment of the present invention.

FIG. 7 is a time chart showing the contents of normal clutch engagement control according to the embodiment of the present invention.

[Explanation of symbols]

 2 Fluid coupling 3 Wet multi-plate clutch 16 Electronic control unit (ECU) 21 Vehicle speed sensor 22 Parking brake switch 23 Foot brake switch 24 Gear position sensor E Engine T / M transmission CSV Clutch solenoid valve CCV Clutch control valve D Duty ratio Dm Torque Point learning value Nt Turbine speed Ne Engine speed ΔN Speed difference Nm Predetermined value

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (reference) F16H 59:54 F16D 25/14 640K F-term (reference) 3J057 AA03 BB04 EE09 GA49 GA66 GA68 GB02 GB13 GB22 GB26 GB30 GB36 GC12 GE01 GE08 GE11 HH01 JJ01 3J552 MA12 MA17 NA01 NB01 PA02 PA20 PA54 QB04 RA02 RB03 SA18 SB05 TA11 TB01 VA07W VA32W VA36Z VA63W VA65Z VA68W VA74Z VB01W VC01W VD11W

Claims (2)

[Claims] A fluid coupling is provided on the upstream side of a power transmission path from an engine to a transmission, and a wet friction clutch is provided in series on a downstream side thereof, and hydraulic fluid pressure is supplied to the wet friction clutch. A fluid pressure supply device for changing the fluid pressure supplied from the fluid pressure supply device in accordance with the duty ratio of the duty pulse output from the electronic control unit. In the power transmission device for a vehicle, the state of which is controlled, when the wet friction clutch is connected from the disengaged state and the torque point at which the predetermined torque is transmitted to the electronic control unit is first learned to the electronic control unit, While detecting the rotational speed of the input side of the friction clutch and the rotational speed of the engine, the duty ratio is changed. Gradually disconnection from contact state to the wet friction clutch Te,
In the process, when a difference between the engine speed and the input-side speed of the wet friction clutch becomes a predetermined value or less, the value of the duty ratio at that time is learned as a torque point. Torque point learning method. 2. The clutch torque point learning method according to claim 1, wherein the torque point learning start conditions include a condition that the vehicle is stopped, a parking brake is operating, a foot brake is operating, and a transmission is geared in.