JP2707505B2 - Slip control method for automatic transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a slip control method for an automatic transmission having a driving force transmitting device having a direct connection mechanism.

[0002]

2. Description of the Related Art An automatic transmission provided in an automobile is provided with a driving force transmitting device, for example, a torque converter, between an internal combustion engine and a gear transmission, and the driving force of the engine is transmitted through the torque converter. To communicate. The torque converter is connected to the crankshaft of the engine, and transmits torque between the impeller rotating integrally with the front cover, the impeller via hydraulic oil, and a turbine connected to the output shaft. It has.

The direct coupling mechanism controls the amount of slip between the turbine and the impeller. In a predetermined operating region of the internal combustion engine, the direct coupling mechanism reduces the slip amount to zero to eliminate energy loss due to slippage between the turbine and the impeller. Improving fuel economy. The wider the direct drive range in which the slip amount is controlled to 0 is, the more the fuel consumption is improved. The direct drive range in which the slip amount is controlled to 0 in a specific drive range such as a low rotational speed range of the internal combustion engine is also provided. Driving is requested.

However, if the slip amount is completely reduced to 0 in a specific operating region such as the low rotation speed region, a so-called "muffled sound" is generated, which causes a problem that the vehicle is not preferable in terms of feeling. .
Therefore, in a specific operation region such as a low rotation speed region, a minute slip direct coupling control that allows a slight slip instead of completely controlling the slip amount to zero has been proposed.

[0005]

In such a minute slip direct coupling control, it is important to stably control the direct coupling mechanism in a region where the slip amount ΔS is extremely small.
As shown by the solid line in FIG. 1, it is necessary to use a hydraulic oil having such a characteristic that the smaller the slip amount ΔS, the smaller the friction coefficient μ of the engagement element of the direct coupling mechanism. In order to obtain such characteristics, special additives are added to the hydraulic oil. However, if the hydraulic oil deteriorates due to long-term use, and the friction coefficient suddenly increases in the small slip amount region as shown by the broken line in FIG. 1, it becomes difficult to control the small slip amount, and the slip amount becomes small. There are problems that a hunting phenomenon occurs and a direct coupling vibration occurs.

The present invention has been made to solve such a problem. In a specific operation region such as a low rotation speed region, direct connection control allowing a slight slip is performed to improve fuel efficiency. The present invention provides a slip control method for an automatic transmission in which direct vibration caused by deterioration of hydraulic oil is accurately detected without providing special detecting means, and the direct vibration is prevented. The purpose is to:

[0007]

To achieve the above mentioned purpose SUMMARY OF THE INVENTION In the present invention, the input coupled to the engine
A force element, an output element coupled to the gear transmission side, and
Has a direct connection mechanism that can connect the above input element and output element
A driving force transmission mechanism, and the input element and the output element
The slip amount detected from the rotational speed difference is equal to the target slip amount.
Automatic transmission with slip control of the direct coupling mechanism
During the preset period in the slip control method
The detected slip amount is the upper limit of the target slip amount.
And the number of changes across the lower limit
When the number of changes made by the
And prohibit the parameter indicating the engine load.
Data values, and changes in the parameter values during the period
Is detected, a change in slip amount for the number of determinations above is detected.
Even if it is done, the above slip control is continued
A slip control method for an automatic transmission is provided.

[0008]

[0009]

When the internal combustion engine is operating in a predetermined operating range, for example, a low rotational speed range, the slip amount of the driving force transmission device is not completely controlled to 0, and the slip of the driving force transmission device is controlled by the direct coupling mechanism. If the control is performed so as to allow it slightly, so-called "muffled sound" does not occur, and the energy loss is small because the slip amount is small.

When the hydraulic oil of the driving force transmission device deteriorates, the slip amount increases and direct coupling vibration occurs. This direct coupling vibration causes the detected slip amount to be larger than the target slip amount during the control of the slip amount. Is stored, and the number of times the value crosses a predetermined lower limit value smaller than the target slip amount is stored, and the number of changes in the stored slip amount is detected. When a predetermined number of changes in the slip amount are detected,
Slip amount control to the target slip amount is prohibited.

If the parameter value representing the engine load such as the throttle valve opening greatly changes during the slip amount control to the target slip amount, the slip amount also changes. It cannot be determined whether or not vibration has occurred, and the slip amount control to the target slip amount is continued.

[0012]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 2 shows the entire configuration of an automatic transmission for an automobile. This automatic transmission is interposed between the gear transmission 10 having four forward and four reverse stages and an internal combustion engine (not shown). The torque converter 20, a differential 30 connected to the output shaft of the gear transmission 10 via the transfer shaft 12 and connected to the axle shaft of the front wheels, a clutch and a brake device of the gear transmission 10, and the torque converter 20 described later. A hydraulic control device 50 that supplies hydraulic oil to a direct coupling mechanism or the like, and a control signal is output to the hydraulic control device 50 to output the torque converter 2
A transmission control unit (hereinafter, referred to as TCU) 40 for controlling the operating oil pressure supplied to the direct coupling mechanism 0 and the like.

The torque converter 20 of the present embodiment includes a slip type direct coupling clutch (damper clutch) 26 as a direct coupling mechanism. The hydraulic control device 50 includes:
A shift valve (not shown) whose valve position is switched by a driver's shift operation, a pressure reducing valve that reduces the line pressure from a hydraulic pump according to the vehicle speed, etc., and a torque converter valve that adjusts the operating oil pressure supplied to the torque converter 20, which will be described later. A damper clutch control valve 52 and the like are provided.

FIG. 3 shows a torque converter 20 and a damper clutch control valve 52 of a hydraulic control device 50 for supplying hydraulic oil thereto. The front cover 21 and the impeller 22 of the torque converter 20 are connected to a crankshaft of the engine via a drive plate (not shown), and when the engine rotates, they integrally rotate like the engine. On the other hand, a turbine 24 is rotatably housed in the front cover 21, and is fixed to an output shaft (input shaft of the gear transmission 10) 25. The torque converter 20 performs a normal operation when a later-described damper clutch 26 of a direct connection mechanism is released, and transmits torque between the impeller 22 and the turbine 24 via hydraulic oil. A damper clutch 26 is interposed between the turbine 24 and the front cover 21, and the damper clutch 26 rotates integrally with the turbine 24 by a lock ring 28.

The damper clutch 26 and the front cover 21
A space 26A is defined therebetween, and the space 26A communicates with the port 21a of the torque converter 20. When hydraulic oil is supplied to the space 26A via the port 21a,
The hydraulic pressure acts on the damper clutch 26 in a direction to separate the damper clutch 26 from the front cover 21, that is, a direction in which the damper clutch 26 slips. The torque converter 20 has another port 21b.
b, the line pressure acts on the surface of the damper clutch 26 on the side opposite to the surface facing the space 26A, and the damper clutch 26
1, the turbine 24 and the impeller 22 rotate integrally, and the slip amount becomes zero. Reference numeral 23 in FIG. 3 denotes a stator, and the one-way clutch 2
9 to a casing 10a (FIG. 2).

The hydraulic control device 50 includes a damper clutch control valve 52 and a solenoid valve 54.
The hydraulic pressure acting on the damper clutch 26 is controlled by the on / off control or the duty control of the control unit 4. More specifically, the damper clutch control valve 52 includes a spool 53 and a spring 55 that presses the left end surface of the spool 53.
The spool 53 is constantly biased by the spring 55 in the right end direction in the figure. The spool 53 has six lands. Various ports are opened and closed by movement of the spool 53, and hydraulic pressure acts on each end face of the lands through the corresponding ports. That is, the ports 52a, 52b
Is supplied from a pressure reducing valve (not shown) to the land surface at the left end and the land surface near the right end of the spool 53. When the solenoid valve 54 is closed, the difference in the land surface area, and thus the right and left directions The difference in working hydraulic pressure,
In addition, the spool 53 is moved to the limit position at the right end in the drawing by the spring force of the spring 55. At this time, the port 52c communicates with the port 52d, and hydraulic oil supplied from a torque converter valve (not shown) is supplied to the port 21a of the torque converter 20 via these ports 52c and 52d. The port 52e and the port 52f are communicated with each other, and the hydraulic oil discharged from the port 21b of the torque converter 20 is returned to the oil pump through these ports 52e and 52f.

When the solenoid valve 54 is opened and the hydraulic pressure acting on the left end land surface of the spool 53 is reduced, the spool 53
Moves to the extreme left end position. At this time, the port 5
2c is communicated with the port 52f, and the operating oil pressure from the torque converter valve is returned to the oil pump without being supplied to the torque converter 20. The port 52d communicates with the port 52g and is connected to the drain. The hydraulic oil acting on the surface of the damper clutch 26 facing the space 26A is changed from the port 21a to the ports 52d and 52g.
Drained to the drain through In addition, port 52i
And port 52j are connected by an oil passage 52k, and port 52i is connected to port 52h to which line pressure is supplied.
The ports 52j are respectively connected to the aforementioned ports 52e.
Therefore, ports 52h, 5
The line pressure is supplied through 2i, 52j, 52e and the port 21b, and this line pressure acts on the damper clutch 26 to press it against the front cover 21.

The hydraulic oil supplied to the torque converter 20 has a characteristic shown by a solid line in FIG. 1. When this hydraulic oil is used, the slip amount Δ
Friction coefficient μ of the damper clutch 26 in a region where S is extremely small.
Can be reduced with a decrease in the slip amount ΔS. The above-described solenoid valve 54 is connected to the output side of the TCU 40, and is turned on / off or duty-controlled by a drive signal from the TCU 40. Returning to FIG. 2, the TCU 40
On the input side, a turbine speed sensor (Nt sensor) 42 for detecting the speed Nt of the turbine 24 of the torque converter 20, an N0 sensor 43 for detecting the speed N0 of the transfer shaft 12, and an engine speed Ne. A Ne sensor 44, a throttle opening (θt) sensor 46 for detecting a valve opening θt of a throttle valve disposed in the middle of the intake passage of the internal combustion engine;
An oil temperature sensor (not shown) for detecting the oil temperature of the working oil supplied to the TCU 40 is electrically connected, and a detection signal from these sensors is supplied to the TCU 40.

The slip amount of the torque converter 20, that is, the slip amount ΔS of the damper clutch 26 is obtained as a deviation (rpm) between the engine speed Ne and the turbine speed Nt. ΔS = Ne−Nt (1) In this embodiment, the slip amount ΔS calculated by equation (1) is used.
However, a ratio (%) of the above-mentioned deviation to the engine speed Ne may be obtained from the following equation (2), and this may be used as the slip amount ΔS.

ΔS = (Ne−Nt) × 100 / Ne (2) The Nt sensor 42 establishes the rotation speed N0 of the transfer shaft 12 detected by the N0 sensor 43 and the gear transmission 10. The turbine speed Nt can be calculated by multiplying by the speed ratio of the current gear stage.
The rotational speed N0 may be used in the calculation of the slip amount ΔS according to (1) or (2).

The TCU 40 includes a ROM, a RAM (not shown)
And the like, and incorporates a central processing unit, an I / O interface, a counter, and the like, and executes shift control and direct connection control in accordance with a control program stored in the storage device. First, the TCU 40 determines the switching position of the shift valve of the hydraulic control device 50 and the rotational speed N detected by the NO sensor 43.
0 (vehicle speed), shift control is performed according to the throttle valve opening θt detected by the throttle opening sensor 46, and the like. Since this control is not particularly related to the present invention, a detailed description thereof will be omitted. However, a control signal is output to the hydraulic control device 50 according to the vehicle speed and the like, and the operating hydraulic pressure is applied to the above-described clutch and brake device of the gear transmission 10. The vehicle is supplied and the required gear is switched and controlled.

Next, the TCU 40 detects a control region of the damper clutch 26 which is determined by the turbine speed Nt detected by the Nt sensor 42 and the throttle valve opening θt detected by the throttle opening sensor 46. FIG. 4 illustrates various control regions of the damper clutch 26. In FIG. 4, a region C indicates a complete direct connection region in which the slip amount of the damper clutch 26 is controlled to zero. This area C is an area in which even if the torque converter 20 is completely connected by operating the damper clutch 26, there is no danger of "muffled sound" or vehicle body vibration due to the direct connection. The areas A and B are a low rotation speed area and a deceleration area, respectively, and show a slip direct connection control area that allows a slight amount of slip. In the areas A and B, when the damper clutch 26 is frictionally engaged with the front cover 21 and is controlled to be in a completely connected state, there is a possibility that “muffled sound” and vehicle body vibration may occur due to the directly connected state. You do it.

More specifically, when it is determined that the shift operation has been completed and the control of the damper clutch 26 has entered the region C based on the detected turbine speed Nt and the throttle valve opening θt. The TCU 40 executes the complete direct connection control. The complete direct connection control in this area C is as follows:
The electromagnetic valve 54 of the hydraulic control device 50 is energized (opened) to move the damper clutch control valve 52 to the left end position, and the line pressure is supplied from the control valve 52 to the torque converter 20 to operate the damper clutch 26. At this time, the damper clutch 26 is pressed by the front cover 21 and the slip amount of the torque converter 20 becomes zero.

If it is determined from the detected turbine speed Nt and throttle opening θt that the control of the damper clutch 26 has entered the region A or B, the TCU 4
0 executes slip direct connection control. This control allows the torque converter 20 to be in a substantially directly connected state by allowing a slight slip. By controlling the duty of the solenoid valve 54, the magnitude of the operating oil pressure supplied to the space 26A of the torque converter 20 is reduced. The slip amount ΔS is adjusted so as to be close to the target slip amount (for example, 100 rpm). Thus, in the regions A and B shown in FIG.
Although the torque converter 20 allows a slight slip, it is kept in a substantially directly connected state, so that energy loss is reduced and fuel efficiency is improved. It should be noted that during the gear shifting operation or in FIG.
In the control areas other than the above-described areas shown in FIG. 7, the damper clutch 26 is released and is in a non-directly connected state. In addition, the above-described complete direct connection control method of the damper clutch 26, that is, a control method for shifting the damper clutch 26 from the slip state to a completely directly connected state or from the completely directly connected state to the slip state, There is no particular limitation on the slip direct connection control method for controlling the vicinity, and various methods can be applied.

Next, a method of detecting direct vibration in slip direct connection control according to the present invention will be described in detail with reference to FIGS. The direct-coupled vibration detection program shown in FIG. 5 simultaneously turns on the ignition key,
This is executed by the TCU 40. First, in step S200, the TCU 40 initializes the count value n6 (n6
= 0). Next, the process proceeds to step S202,
It is determined whether or not the damper clutch 26 is controlled within the slip direct connection control region (region A or B shown in FIG. 4). If it is not controlled in this area (if the determination result is negative (No)), step S202 is repeatedly executed and the process stands by.

If the decision result in the step S202 is affirmative (Ye)
s), if the damper clutch 26 is under slip direct connection control, the process proceeds to step S204 to detect a slip of the torque converter 20 (hereinafter, referred to as "torque slip"). The details of a method of detecting whether the torque converter slip exceeds an allowable range (predetermined upper and lower limit values) will be described later. However, when the slip amount is within an allowable range (when the determination result in step S204 is negative). Returns to step S202 described above, and repeatedly executes steps S202 and S204 until an unacceptable torque converter slip is detected.

On the other hand, if an unacceptable torque converter slip is detected in step S204, the occurrence of direct vibration is predicted, and the flow advances to step S206 to add the value 1 to the stored count value n6. This is stored as a new count value n6. Then, it is determined whether or not the count value n6 is equal to or more than a predetermined value (for example, 4) (step S208). If the count value n6 has not yet reached the predetermined value (4), torque converter slip occurs. The process returns to step S202, assuming that it is not possible to determine. However, when the count value n6 has reached the predetermined value (4), it is determined that direct vibration has occurred, and a flag indicating that direct vibration has been detected is set (step S210). As described above, when the direct vibration is detected, a specific warning lamp of a failure diagnosis device (not shown) is turned on and stored, and the damper clutch 26 is operated until an appropriate measure such as replacement of hydraulic oil is performed. Slip direct connection control is prohibited, and control other than slip direct connection control, for example, non-direct connection control, is executed. Whether or not the above-described appropriate action has been performed is identified by, for example, resetting the above-described direct vibration detection flag when the terminal of the battery power supply is disconnected and connected again. Then, if the direct vibration detection flag is reset, the slip direct control may be restarted.

The control method of the damper clutch 26 executed when the direct vibration is detected and the slip direct control is prohibited is not limited to the non-direct control described above, but may be a control method that does not generate the direct vibration. I just need. Accordingly, although a slight muffled sound is generated, complete direct connection control can be performed. FIG. 6 to FIG. 9 show steps S in FIG.
The procedure for detecting torque converter slip executed in step 204, that is, the procedure for detecting directly-coupled vibration will be described. The TCU 40 first
In step S220, the count value K is initialized to a value of 0, the throttle valve opening minimum value Thmin to a value of 100 (%), and the throttle valve opening maximum value Thmax to a value of 0 (%). The count value K is, as described later,
This is to count the number of times the slip amount has changed beyond the predetermined upper and lower limit values within a predetermined period. The throttle valve opening minimum value Thmin and the throttle valve opening maximum value Thmax are variables for storing the minimum and maximum values of the throttle valve opening within the above-described predetermined period.

Next, after the TCU 40 enters the above-described slip direct connection control region, the TCU 40 starts the slip direct connection control of the damper clutch 26 to determine whether or not the slip amount is sufficiently settled near the aforementioned target slip amount. Then, it is determined whether or not the rush control has been completed (step S222). If the rush control has not been completed, step S222 is repeatedly executed until the rush control is completed.

If the entry control is completed and the result of the determination in step S222 is affirmative, the process proceeds to step S224, where the timer value T2 is reset to zero. The timer T2 is a counter for measuring a predetermined period (for example, a value corresponding to 4 seconds). The timer value is incremented by a minute value each time a predetermined time elapses. It is determined that the predetermined period has elapsed.

Next, it is determined whether or not the slip amount ΔS is equal to or less than a predetermined lower limit (for example, 50 rpm) set to a value smaller than the above-mentioned target slip amount (100 rpm) (step S226). If this answer is negative, in step S228, the damper clutch 26
After determining whether or not is controlled in the slip direct connection control area, step S224 is executed again to reset the timer value T2 to the value 0, and wait until the slip amount ΔS becomes equal to or less than the lower limit value. In a case where the state in which the damper clutch 26 is to be controlled in an area other than the slip direct coupling control area during the standby state, that is, in a case where the determination result of step S228 is negative, after executing step S256 described later, Proceeding to step S262, it is determined that torque converter slip has not been detected, and the routine is terminated. For example, a predetermined flag value is reset to 0 to store that torque converter slip has not been detected. In this case, if the routine is executed again, step S
The flow returns to 220 to resume from resetting the count value K and the like.

If the result of the determination in step S226 is affirmative, that is, if the slip amount ΔS is equal to or less than the lower limit (50 rpm), the flow proceeds to step S230 in FIG. At this time, the timing of the timer value T2 is substantially started (FIG. 10).
At time t10). In step S230, the slip amount ΔS
Is greater than or equal to a predetermined upper limit (for example, 150 rpm) set to a value larger than the target slip amount (100 rpm) described above. When the slip amount ΔS has just exceeded the above lower limit value, this determination result is naturally negative, and steps S232 to S240 are repeatedly executed until the determination result in step S230 becomes positive. In these steps, the maximum value and the minimum value of the detected throttle valve opening .theta.t are stored. In step S232, the detected throttle valve opening .theta.t is stored in the maximum value Thmax.
It is determined whether or not it is larger, and if it is larger, step S2 is performed.
The maximum value Thmax stored in step 34 is updated to the throttle valve opening θt detected this time. Step S23
In the step S238, it is determined whether or not the detected throttle valve opening θt is smaller than the stored minimum value Thmin.
hmin is updated to the throttle valve opening θt detected this time.
Then, in step S240, it is determined whether or not the timer value T2 has reached the predetermined value (50). If not, step S230 and subsequent steps are executed again. In this manner, the detected maximum value Thmax and minimum value Thmin of the throttle valve opening are sequentially updated until the predetermined period (4 seconds) elapses.

If the slip amount .DELTA.S exceeds the upper limit (150 rpm) (at time t12 in FIG. 10) and the determination result in step S230 becomes positive, the process proceeds to step S242 in FIG. In this step S242, the slip amount ΔS is again reduced to the lower limit value (5
0 rpm) or less. When the slip amount ΔS has just exceeded the upper limit value, the result of this determination is negative, and steps S246 to S254 are repeatedly executed. These steps are for sequentially updating the minimum value Thmin and the maximum value Thmax of the detected throttle valve opening θt, similarly to the above-described steps S232 to S240.
In steps S246 and S248, the maximum value Thmax
Is updated, and the minimum value Thmin is updated in steps S250 and S252. Then, in step S254, the timer value T2 is compared with the predetermined value (50), and if the timer value T2 has not reached the predetermined value, steps S242 and subsequent steps are executed again.

The slip amount ΔS changes and the lower limit (50 rp)
m) or less (time t13 in FIG. 10), step S24
4 is executed. In this step, the value 1 is added to the stored value of the count value K, and this is set as a new stored value. Then, returning to step S230 in FIG. 7, it is determined again whether or not the slip amount ΔS is equal to or more than the upper limit value (150 rpm). As described above, the count value K is incremented by repeating steps S230 to S244 in the same manner. That is, after the slip amount ΔS exceeds the upper limit value, every time the slip amount ΔS becomes equal to or less than the lower limit value, the count value K is incremented to the value 1, and such a change in the slip amount ΔS is sequentially counted until a predetermined period elapses. Go.

If it is determined in step S240 or S254 that the timer value T2 has reached the predetermined value (50), the TCU 40 proceeds to step S256 in FIG. Step S256 and subsequent step S258 are for determining whether the torque converter slip has occurred a predetermined number of times in a predetermined period, that is, for example, whether it is two or more and four or less. In the case where the hydraulic oil of the torque converter 20 is deteriorated to cause direct coupling vibration, it has been empirically known that the rotation at which this kind of torque converter slip occurs is within the above-mentioned range. Therefore, when the determination result of either step S256 or step S258 is negative, it is determined that the torque converter slip corresponding to the direct vibration has not occurred (step S2).
62). In this case, for example, the aforementioned specific flag value, which means that torque converter slip has not occurred, is reset.

Steps S256 and S258
Are positive, it means that torque converter slip has occurred during the slip direct connection control. In such a case, the throttle valve opening θt
Is changed to the extent that torque converter slip occurs. That is, if the throttle valve opening θt changes greatly during the predetermined period, it means that the load of the engine changes suddenly. In such a case, the torque converter slip easily occurs. It is difficult to determine whether or not it has occurred. Specifically, it is determined whether or not the difference between the detected maximum value Thmax and the minimum value Thmin of the throttle valve is equal to or smaller than a predetermined value (for example, 30%) (step S260). If this determination is affirmative, that is, if the torque converter slip occurs during the slip direct connection control and the change in the throttle valve opening θt is not large,
It is determined that the torque converter slip corresponding to the direct vibration has occurred, and, for example, the above-described specific flag is set (step S264).

In the above embodiment, the slip amount ΔS
After the value exceeds the upper limit (150 rpm), the change that becomes equal to or less than the lower limit (50 rpm) is counted. May be performed, or both of them may be counted. Although the throttle valve opening θt is used as a parameter value representing the engine load, the present invention is not limited to this, and may be a fuel supply amount, an intake air amount, an intake passage negative pressure, or the like.

Further, the direct connection mechanism is not limited to the damper clutch 26 of the above-described embodiment, and it goes without saying that various clutch devices can be applied.

[0039]

As is clear from the above description, according to the slip control method for an automatic transmission according to the present invention, the preset
During the specified period, the detected slip
Memorize the number of changes across the upper and lower limits,
When the stored change count reaches the judgment count, the slip
Control and a parameter that indicates the engine load.
Data value and detect the fluctuation of the parameter value during the period.
When a change is detected, the change in the slip amount
It is characterized in that the slip control is continued even in the event of a slip .

Therefore, the direct coupling vibration can be detected by counting the number of times of the change in the slip amount exceeding the allowable range. Until the direct coupling vibration occurs due to the deterioration of the hydraulic oil of the driving force transmission device, the direct coupling mechanism causes the slip. The amount of slip can be controlled to be close to the target amount of slip, and fuel efficiency can be improved.On the other hand, if the amount of slip exceeds the allowable range, it can be accurately detected and caused by deterioration of hydraulic oil, etc. Direct vibration can be reliably prevented, and a situation in which the occupant feels uncomfortable due to the direct vibration can be prevented.

[Brief description of the drawings]

FIG. 1 is a graph for explaining a preferable relationship between a slip amount ΔS of a damper clutch of a torque converter and a friction coefficient μ.

FIG. 2 is a block diagram showing an overall configuration of an automatic transmission to which the direct connection control method of the present invention is applied.

FIG. 3 is a torque converter 2 of the automatic transmission shown in FIG. 2;
FIG. 2 is a hydraulic circuit diagram illustrating a main part of a hydraulic control device.

FIG. 4 is a damper clutch 2 defined by an output shaft rotation speed Nt of the torque converter 20 and a throttle valve opening θt.
6 is a graph showing a control region No. 6;

FIG. 5 is a flowchart showing a procedure for detecting direct coupling vibration by a transmission control unit (TCU) 40 shown in FIG. 2;

FIG. 6 is a partial flowchart showing a procedure for detecting a change in the slip amount of the torque converter 20 by the transmission control unit (TCU) 40.

FIG. 7 is a partial view of a flowchart showing a procedure for detecting a change in the slip amount.

FIG. 8 is a partial flowchart showing a procedure for detecting a change in the slip amount.

FIG. 9 is a partial flowchart showing a procedure for detecting a change in a slip amount.

FIG. 10 is a graph showing a time change of a slip amount ΔS.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Gear transmission 12 Transfer shaft 20 Torque converter 26 Damper clutch 30 Differential 40 Transmission control unit (T
CU) 42 Turbine speed (Nt) sensor 43 N0 sensor 44 Engine speed Ne sensor 46 Throttle opening (θt) sensor 50 Hydraulic control device 52 Damper clutch control valve 54 Solenoid valve

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Youichi Furuichi 5-33-8 Shiba, Minato-ku, Tokyo Inside Mitsubishi Motors Corporation (72) Inventor Kenji Suzuki 5-33-8 Shiba, Minato-ku, Tokyo No. Mitsubishi Motors Corporation (56) References JP-A-60-151457 (JP, A) JP-A-59-113365 (JP, A) JP-A-60-14653 (JP, A)

Claims (1)

(57) [Claims] An input element and a gear connected to an engine.
An output element connected to the transmission, and the input element
Force transmission with a direct connection mechanism that can connect the motor and the output element
Equipped with a mechanism, based on the rotational speed difference between the input element and the output element.
Increase the detected slip amount to the target slip amount.
Slip of automatic transmission that controls slippage of direct-coupled mechanism
In the control method, during the preset period, the detected slip amount is set to the target value.
Changed across the upper and lower limits of the target slip amount
The number of times is memorized, and the memorized number of changes becomes the number of judgments
Prohibits the slip control , detects a parameter value representing the load of the engine,
When a change in the above parameter value is detected during the period,
When a slip amount change in the number of determinations is detected,
Also, the above-mentioned slip control is continued.
A slip control method for a dynamic transmission.