JPH07107426B2 - Direct connection 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 direct connection control method for an automatic transmission equipped with a drive force transmission device having a direct connection mechanism.

[0002]

2. Description of the Related Art An automatic transmission provided in an automobile has a driving force transmission device, for example, a torque converter, interposed between an internal combustion engine and a gear transmission, and the driving force of the engine is transmitted through the torque converter. Have been communicated to. The torque converter transmits torque between the impeller that is connected to the crankshaft of the engine and rotates integrally with the front cover, and the turbine that is connected to the output shaft by transmitting torque between the impeller and the direct coupling mechanism. Is equipped with.

The direct coupling mechanism controls the slip amount 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 eliminate the energy loss due to the slip between the turbine and the impeller. We are trying to improve fuel efficiency. The wider the direct-coupling operating range in which the slip amount is controlled to 0, the better the fuel economy is, and the direct-coupling in which the slip amount is controlled to 0 is controlled even in a specific operating region such as the low rotation speed region of the internal combustion engine. Driving is requested.

However, when the slip amount is completely set to 0 in a specific operating region such as the low rotation speed region, a so-called "muffled noise" is generated in the vehicle body, which is not preferable in terms of feeling. .
Therefore, in a specific operation region such as a low rotation speed region, a slight slip direct coupling control is proposed in which the slip amount is not completely controlled to 0 but slight slip is allowed.

[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 hydraulic oil that has characteristics such that the smaller the slip amount ΔS, the smaller the friction coefficient μ of the engaging 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 rapidly increases in the minute slip amount region as shown by the broken line in FIG. 1, it becomes difficult to control the minute slip amount, and the slip amount There is a problem that a hunting phenomenon occurs or a direct coupling vibration occurs.

The present invention has been made to solve such a problem, and in a specific operating region such as a low rotation speed region, direct connection control that allows a slight slip is performed to improve fuel efficiency. Provided is a direct-coupling control method for an automatic transmission that accurately detects this direct-coupling vibration and prevents it when a direct-coupling vibration occurs due to deterioration of hydraulic oil without providing a special sensor. With the goal.

[0007]

In order to achieve the above-mentioned object, the present invention comprises a drive force transmission device having a direct coupling mechanism, which is interposed between an internal combustion engine and a gear transmission, and the direct coupling mechanism is provided. In the direct-coupling control method for an automatic transmission capable of controlling the slip amount of the driving force transmission device according to the above, when the internal combustion engine is operating in a predetermined operating range, the slip amount is within a predetermined value range by the direct-coupling mechanism. And the rotation speed of the output shaft of the driving force transmission device is monitored, and when the rotation speed fluctuation of the output shaft exceeds an allowable range, the direct coupling mechanism is opened to stop the control of the slip amount. Detecting the rotational speed of the output shaft to determine whether the rotational fluctuation of the output shaft is within the allowable range, and if the rotational fluctuation of the output shaft still exceeds the allowable range, the slip occurs. Control of quantity While resuming, when returned to within the allowable range direct control method for automatic transmission and inhibits the control of the slip amount is provided.

[0008]

When the internal combustion engine is operated in a predetermined operating range, for example, a low rotational speed range, the slip amount of the driving force transmitting device is not completely controlled to 0, and the slip of the driving force transmitting device is prevented by the direct coupling mechanism. When the control is performed so as to be slightly permitted, so-called "muffled noise" does not occur, and since the slip amount is small, the energy loss is small.

When the fluctuation of the rotational speed of the output shaft exceeds the allowable value range during the control of the slip amount, the fluctuation of the rotational speed is caused by the deterioration of the hydraulic oil of the driving force transmission device or the condition of the road surface. It is unknown whether to do it. Therefore, by temporarily stopping the slip amount control and then again determining whether or not the rotational fluctuation of the output shaft is within the allowable range, it is possible to determine which cause causes the rotational speed fluctuation. Become. That is, if the rotation fluctuation returns to within the allowable range, it can be determined that the rotation speed fluctuation is caused by the slip amount control, and in this case, the slip amount control is prohibited. On the other hand, when the allowable range is still exceeded, it can be determined that the rotational speed fluctuation is caused by the road surface condition or the like, and in this case, the slip amount control is continued.

[0010]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 2 shows the overall configuration of an automatic transmission for an automobile. This automatic transmission is a gear transmission 10 having four forward gears and one reverse gear, and is interposed between the gear transmission 10 and an internal combustion engine (not shown). A torque converter 20, a differential 30 connected to the output shaft of the gear transmission 10 via a transfer shaft 12 and connected to an axle shaft of a front wheel, a clutch and a brake device of the gear transmission 10, and a torque converter 20 which will be described later. The torque converter 50 that supplies hydraulic oil to the direct coupling mechanism or the like, outputs a control signal to the hydraulic control device 50, and outputs the torque converter 2
It is composed of a transmission control unit (hereinafter referred to as TCU) 40 and the like for controlling the hydraulic pressure supplied to the direct coupling mechanism of No. 0.

The torque converter 20 of this embodiment is provided with a slip type direct coupling clutch (damper clutch) 26 as a direct coupling mechanism. Further, the hydraulic control device 50 includes
A shift valve (not shown) whose valve position is switched by the driver's shift operation, a pressure reducing valve for reducing the line pressure from the hydraulic pump according to the vehicle speed, etc., a torque converter valve for adjusting the operating hydraulic 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 the torque converter 20 and the damper clutch control valve 52 of the hydraulic control device 50 which supplies hydraulic oil to the torque converter 20. The front cover 21 and the impeller 22 of the torque converter 20 are connected to the crankshaft of the engine via a drive plate (not shown), and when the engine rotates, they integrally rotate in the same manner as the engine. On the other hand, a turbine 24 is rotatably accommodated 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 normal operation when the damper clutch 26 of the direct coupling mechanism, which will be described later, is released, and torque is transmitted 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,
Hydraulic pressure acts on the damper clutch 26 in the direction in which it separates from the front cover 21, that is, in the direction in which the damper clutch 26 slips. The torque converter 20 has another port 21b.
When a line pressure to be described later is supplied from b, this line pressure acts on the surface of the damper clutch 26 opposite to the surface facing the space 26A to operate the damper clutch 26 in the front cover 2
When it is pressed against 1, the turbine 24 and the impeller 22 rotate together, and the slip amount becomes zero. Reference numeral 23 in FIG. 3 is a stator, and the one-way clutch 2
It is connected to the casing 10a via 9 (FIG. 2).

The hydraulic control device 50 is provided with a damper clutch control valve 52 and a solenoid valve 54, and the solenoid valve 5
The hydraulic pressure acting on the damper clutch 26 is controlled by turning ON / OFF of 4 or duty control. 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 urged by the spring 55 toward the right end in the figure. The spool 53 has six lands, and various ports are opened and closed by the movement of the spool 53, and hydraulic pressure is applied to each end surface of the lands via the corresponding ports. That is, the ports 52a and 52b
Is supplied with a hydraulic pressure acting on the land surface at the left end and the land surface near the right end of the spool 53 from a pressure reducing valve (not shown), and when the solenoid valve 54 is closed, the area of the land surface is different, and accordingly, in the right and left directions. The difference in the hydraulic pressure that acts,
In addition, the spring force of the spring 55 causes the spool 53 to move to the extreme right end position in the drawing. At this time, the port 52c and the port 52d are communicated with each other, and the hydraulic oil supplied from the torque converter valve (not shown) is supplied to the port 21a of the torque converter 20 through these ports 52c and 52d. Further, the ports 52e and 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 via these ports 52e and 52f.

When the solenoid valve 54 opens and the hydraulic pressure acting on the land surface at the left end of the spool 53 is reduced, the spool 53
Moves to the extreme left position. At this time, the above-mentioned 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 supplied from the port 21a to these ports 52d and 52g.
Is discharged to the drain via. In addition, port 52i
And the port 52j are connected by the oil passage 52k, and the port 52i is connected to the port 52h to which the line pressure is supplied.
The ports 52j are connected to the above-mentioned ports 52e, respectively.
Therefore, the torque converter 20 has ports 52h, 5
Line pressure is supplied via 2i, 52j, 52e and the port 21b, and this line pressure acts on the damper clutch 26 and presses it against the front cover 21.

As the working oil supplied to the torque converter 20, one having the characteristics shown by the solid line in FIG. 1 is used. When this working oil is used, the slip amount Δ
Friction coefficient μ of damper clutch 26 in a region where S is extremely small
Can be reduced as the slip amount ΔS decreases. The 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 TCU40
A turbine speed sensor (Nt sensor) 42 for detecting the speed Nt of the turbine 24 of the torque converter 20, a N0 sensor 43 for detecting the speed N0 of the transfer shaft 12, and an engine speed Ne are detected on the input side of the. A Ne sensor 44, a throttle opening (θt) sensor 46 for detecting a valve opening θt of a throttle valve disposed in the intake passage of the internal combustion engine, a hydraulic pump to a hydraulic control device 50.
An oil temperature sensor (not shown) or the like for detecting the oil temperature of the hydraulic oil supplied to is electrically connected, and detection signals from these sensors are supplied to the TCU 40.

As shown in FIG. 5, the N0 sensor 43 is mounted on the outer periphery of the transfer shaft driven gear 12a fixed to the transfer shaft 12 so as to face it. The N0 sensor 43 generates a pulse signal each time each tooth of the gear 12a passes (see FIG. 6), and the rotation speed N0 is calculated from the time interval of the pulse signal generation. It should be noted that the Nt sensor 42 detects the rotation speed N0 of the transfer shaft 12 detected by the N0 sensor 43 and the gear transmission 1
Since it is possible to calculate the turbine speed Nt by multiplying it by the established gear ratio of 0, it is possible to omit this.

The TCU 40 is a ROM, RAM (not shown)
It has a built-in storage device such as a storage device, a central processing unit, an I / O interface, a counter, etc., and executes shift control and direct connection control according to a control program stored in the storage device. First, the TCU 40 has a shift valve switching position of the hydraulic control device 50 and a rotation speed N detected by the N0 sensor 43.
The shift control is performed according to 0 (vehicle speed), the throttle valve opening θt detected by the throttle opening sensor 46, and the like. Although 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 or the like to apply the operating hydraulic pressure to the above-mentioned clutch and brake device of the gear transmission 10. It is supplied and is controlled to switch to the required gear.

Next, the TCU 40 detects the 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 exemplifies various control regions of the damper clutch 26. In FIG. 4, a region C shows a completely direct coupling region in which the slip amount of the damper clutch 26 is controlled to zero. This region A is a region in which there is no risk of "muffled noise" or vibration of the vehicle body due to the direct connection even if the damper clutch 26 is operated to completely connect the torque converter 20. Regions A and B are a low rotation speed region and a deceleration region, respectively, and show a slip direct coupling control region in which slip is slightly permitted. If the damper clutch 26 is frictionally engaged with the front cover 21 and is completely connected to the regions A and B, there is a risk of "muffled noise" or vehicle vibration due to the direct connection, so slight slippage is allowed. To do.

More specifically, when the shift operation is completed and it is determined that the control of the damper clutch 26 has entered the region C based on the detected turbine speed Nt and throttle valve opening θt. To this end, the TCU 40 executes a complete direct connection control. The complete direct connection control in this area C is
The solenoid valve 54 of the hydraulic control device 50 is urged (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.

When it is determined that the control of the damper clutch 26 has entered the region A or B based on the detected turbine speed Nt and the throttle valve opening θt, the TCU4
0 executes slip direct connection control. In this control, a slight slip is allowed in the torque converter 20 to bring the torque converter 20 into a substantially directly connected state, and by controlling the duty of the solenoid valve 54, the magnitude of the working hydraulic pressure supplied to the above-described space 26A of the torque converter 20 is increased. It is adjusted and the slip amount ΔS is controlled within a predetermined range (for example, 40 to 60 rpm). As described above, in the regions A and B shown in FIG. 4, the torque converter 20 is allowed to slip slightly, but is held in a substantially direct connection state, so that energy loss is reduced and fuel consumption is improved. Note that the damper clutch 26 is disengaged and brought into a non-direct connection state during a gear shift operation or in a control region other than the above-described region shown in FIG. Further, the above-described complete direct connection control method for the damper clutch 26, that is, a control method for shifting the damper clutch 26 from a slip state to a complete direct connection state or from a complete direct connection state to a slip state, and a slip amount within a predetermined value range. The slip direct coupling control method to be internally controlled is not particularly limited, and various methods can be applied.

Next, the method for detecting the direct coupling vibration in the slip direct coupling control according to the present invention will be described in detail with reference to FIGS. 7 to 13. The direct-coupling vibration detection program shown in FIG. 7 is executed by the TCU 40 at the same time when the ignition key is turned on. The TCU 40 first executes initialization (n1 = 0) of the count value n1 in step S10. Next, the slip direct connection controllable flag is set (step S12). This controllable flag indicates that the hydraulic oil of the torque converter 20 is at a predetermined temperature (for example, 70 ° C.) or higher, that the gear shifting operation has been completed, that the gear is operating at a gear other than the first gear. The conditions must be met at the same time. If this condition is not satisfied, the process stands by in step S12. Then, the process proceeds to step S14, and it is determined whether or not the damper clutch 26 is controlled within the slip direct coupling control region (region A or B shown in FIG. 4). When not controlled in the area (the determination result is negative (N
In the case of o)), step S14 is repeatedly executed and stands by.

The determination result of step S14 is affirmative (Yes
s), and if the damper clutch 26 is under slip direct coupling control, the routine proceeds to step S16, and the rotation fluctuation of the output shaft of the torque converter 20 is detected from the fluctuation of the rotation speed N0 detected by the N0 sensor 43. The details of the method (1) for detecting the fluctuation of the rotation speed N0 will be described later, but if the fluctuation of the rotation speed N0 is within the allowable range (if the determination result in step S16 is negative), Returning to step S12, the steps below are repeatedly executed until the rotation speed N0 changes.

On the other hand, in step S16, the rotation speed N
When it is detected that there is an unacceptable fluctuation in 0, the process proceeds to step S18, the damper clutch 26 is forcibly released once, and the slip amount control is stopped (forced non-direct connection). Again, the fluctuation of the output shaft of the torque converter 20 is detected from the rotational speed N0 detected by the N0 sensor 43 (step S20). The method (2) for detecting fluctuations in the rotational speed N0 in step S20 is also performed in step S20.
Although it is similar to the detection method (1) in 16, the detection method (2) will be described later. In the variation detection of the rotational speed N0 in step S20, if the variation of the rotational speed N0 that cannot be permitted again is detected even though the damper clutch 26 is forcibly made non-directly connected (the determination result of step S20 is In the case of affirmative), this fluctuation of the rotational speed N0 does not occur due to the slip direct connection control of the damper clutch 26, but means that it is due to the road surface condition transmitted from the wheels. is doing. In such a case, there is no problem even if the slip direct connection control of the damper clutch 26 is restored, and step S1 is performed.
Returning to step 2, the slip direct connection controllable flag is set.
Therefore, when the damper clutch 26 is in a state where it should be controlled in the slip direct connection control region, the control is restarted.

If the determination result in step S20 is negative,
That is, when the change in the rotational speed N0 is no longer detected due to the forced non-direct connection of the damper clutch 26, the change in the rotational speed N0 that occurs during the slip direct connection control of the damper clutch 26 is caused by the slip direct connection control. It means that it had occurred. Therefore, in such a case, it is predicted that the hydraulic oil supplied to the torque converter 20 is deteriorated. Therefore, the process proceeds to step S22, and the value 1 is added to the stored count value n1 and the value is stored as a new count value n1. Then, it is determined whether or not the count value n1 is less than or equal to a predetermined value (for example, 4) (step S24). If the count value n1 has not yet reached the predetermined value (4), the fluctuation of the rotational speed N0 is directly connected to the slip. Since it cannot be determined that it is caused by the control, the process returns to step S12. However, when the count value n1 reaches the predetermined value (4), the rotation speed N
It is determined that the variation of 0 is caused by the slip direct coupling control, and a flag indicating that the direct coupling vibration is detected is set (step S26). As described above, when the direct coupling vibration is detected, a specific warning light of a failure diagnosis device (not shown) is turned on and stored, and the damper clutch 26 of the damper clutch 26 is changed until an appropriate action such as replacement of hydraulic oil is executed. The slip direct connection control is prohibited, and the non-direct connection control is executed. Whether or not the above-mentioned appropriate measures have been executed is identified by, for example, resetting the above-mentioned direct-coupling vibration detection flag when the terminal of the battery power supply is disconnected and then connected again. Then, if the direct coupling vibration detection flag is reset, the slip direct coupling control may be restarted.

The control method of the damper clutch 26 executed when the direct coupling vibration is detected and the slip direct coupling control is prohibited is not limited to the non-direct coupling control described above, and may be any control method in which the direct coupling vibration does not occur. Good. Therefore, although a “muffled sound” is generated to some extent, complete direct connection control can be performed. 8 to 10 show the procedure (1) for detecting the presence or absence of fluctuations in the rotation speed N0, that is, the direct coupling vibration, which is executed in step S16 of FIG. TCU40 is
First, in steps S30 to S34, the count values n2, n3 and the timer value Timer are reset to 0, respectively. The timer Timer has one calculation cycle (for example, 100 mse
(a value equivalent to c) is a counter for timing, and increments the timer value to a small value each time a predetermined time elapses, and when a predetermined value (for example, 1) is reached, it is determined that one operation cycle has elapsed. It is a thing. The count value n3 indicates the number of times the rotation speed N0 fluctuates in a single operation cycle and exceeds a predetermined value, and the vibration frequency is detected from the count value n3. The count value n2 indicates the number of times the vibration in the predetermined frequency range is continuously detected during the operation in the slip direct coupling control range. These count values n2 and n3 are stored in the storage device described above.

Next, the rotation speed N detected by the N0 sensor 43
Deviation Δ0 between current value and previous value of 0 (= N0n-N0n-1)
It is determined whether is a negative number (step S36). If it is not a negative number, in the next step S38 the damper clutch 26
After determining whether is controlled in the slip direct-coupling control region, the process returns to step S34, the timer value Timer is reset to 0 again, and step S36 is repeatedly executed until the deviation ΔN0 becomes a negative number. Become. When it is determined in the above step S38 that the slip direct connection control region is not controlled, the process proceeds to step S40,
It is determined that the number of revolutions N0 has not changed, and for example, a predetermined flag value is reset to 0 and the routine is finished.
In this case, the process returns to step S30 and restarts from the reset of the count value n2.

When the determination result of step S36 is affirmative, that is, when the deviation ΔN0 changes from a positive number to a negative number, the process proceeds to step S42 in FIG. 6 (A) and 6 (B) show the generation state of the pulse signal output from the N0 sensor 43 and the time change of the rotational speed N0 calculated from the output pulse signal, respectively. The fact that the deviation ΔN0 has changed from a positive number to a negative number in S36 means that the detected rotational speed N0 has changed from an increase to a decrease, and the timer Timer reset in step S34 is set at the time t0 of FIG. It will start counting from. Then, in step S42, it is determined whether or not the deviation ΔN0 has changed from a negative number to a positive number.
That is, it is determined whether or not the rotational speed N0 has changed from a decrease to an increase. If the answer is negative, it is determined in step S44 whether or not the timer value Timer has reached the predetermined value (1), and then step S42 is executed again to wait until the rotation speed N0 becomes 0 or more.

If the determination result in step S42 is affirmative, the process proceeds to step S46, in which the time interval between the current and previous pulse signals output from the N0 sensor 43 is Tma.
It is stored as x (near time t1 in FIG. 6). Next, in step S48, it is determined whether or not the deviation ΔN0 is a negative number, and while the timer value Timer is being monitored (step S50), the process waits until the deviation ΔN0 changes from a positive number to a negative number. When the deviation .DELTA.N0 changes to a negative number in step S48, the process proceeds to step S52, and the pulse signal generation time interval of the N0 sensor 43 at the time of change is stored as Ta (near time t2 in FIG. 6).

By calculating the respective reciprocal values of the pulse signal generation time intervals Tmax and Ta thus obtained, the value corresponding to the rotational speed N0 is obtained, and the difference value between these reciprocal values is a predetermined value ( For example, it is determined whether or not it is larger than the value 20 corresponding to 50 rpm (step S5).
4). (1 / Ta)-(1 / Tmax) ≧ 20 (A1) If the relationship of the above expression (A1) is established (if the determination result of step S54 is affirmative), the fluctuation of the rotational speed N0 is predetermined. Value (50r
pm) is greater than
The value 1 is added to the stored value of the count value n3 to store and update it (step S56). On the other hand, when the expression (A1) is not satisfied (when the determination result of step S54 is negative),
The step S42 is performed without adding any change to the count value n3.
Return to. In this way, the steps starting from step S42 are repeatedly executed again, and the number of fluctuations of the rotational speed N0 exceeding the predetermined value during one calculation time is counted. Then, in step S44 or step S50, when the timer value Timer has reached the predetermined value and one calculation time has elapsed, the process proceeds to step S58 in FIG.

In step S58 and the subsequent step S60, the count value n3 obtained as described above is a value between a predetermined lower limit value (for example, value 1) and an upper limit value (for example, value 5). Or not. These determinations identify the frequency of vibration due to fluctuations in the rotational speed N0. During the slip direct coupling control, the torque converter 2
If the vibration is 0 caused by deterioration of the hydraulic oil, the count value n3 has a frequency corresponding to a value within the upper and lower limit value range described above. Therefore, if the determinations at steps S58 and S60 are both negative, it is determined that the rotation speed N0 corresponding to the direct coupling vibration has not changed (step S70). In this case, for example, the aforementioned specific flag value, which means that the rotation speed N0 has not changed, is reset.

If the determination results of step S58 and step S60 are both affirmative, it means that the direct coupling vibration occurred during the slip direct coupling control. In such a case,
The value 1 is added to the stored value of the counter value n2, and this is stored as a new stored value (step S62). Then, it is determined whether or not the updated value of the counter value n2 is equal to or larger than a predetermined value (for example, value 5) (step S64). If the determination result is negative, it is determined in step S66 whether or not the slip direct coupling control region is being controlled. If the slip direct coupling control region is being controlled, the process returns to step S32 to set the count value n3. After resetting, the detection of the number of fluctuations of the rotation speed N0 during one calculation period is repeated. On the other hand, during the detection, when the slip direct coupling control area is left and the control area is shifted to another control area, that is, step S6.
If the determination result of 6 is negative, the above-described step S70
Then, it is determined that there is no fluctuation in the rotational speed N0.

When the result of the determination in step S64 is affirmative, that is, when the direct coupling vibration is detected a predetermined number of times (5 times) continuously during the slip direct coupling control, the routine proceeds to step S68, where the fluctuation of the rotational speed N0 changes. It is determined that it has occurred, and for example, the above-mentioned specific flag is set. Figure 1
1 to 13 show whether or not the fluctuation of the rotational speed N0, which is executed in step S20 of FIG. 7 described above, is detected, that is, the direct coupling vibration is detected again after the damper clutch 26 is forcibly decoupled. A procedure (2) for determining whether or not to perform is shown. Since this detection procedure is substantially the same as that described in FIGS. 8 to 10, it will be briefly described below.

The TCU 40 first resets the count values n4 and n5 and the timer value Timer to 0 in steps S80 to S84. These count values n4 and n5 and the timer value Timer are used for the same purpose as the above-mentioned count value n2, etc.
er is a counter for measuring one operation cycle (for example, a value corresponding to 100 msec). The count value n3 indicates the number of times the rotation speed N0 fluctuates in excess of a predetermined value, and the count value n2 indicates that the vibration in the predetermined frequency range continues during operation in the slip direct coupling control region. Indicates the number of times detected.

Next, the rotation speed N detected by the N0 sensor 43
Deviation ΔN0 (= N0n-N0n-1) between the current value of 0 and the previous value
Is a negative number (step S86). If it is not a negative number, it is determined in the next step S88 whether the timer value Timer has reached the predetermined value (1), and then step S8.
Returning to step 6, the step S86 is repeatedly executed until the deviation ΔN0 becomes a negative number, and the process stands by. When the timer value Timer reaches the predetermined value in step S88 during this standby, the process proceeds to step S90, where it is determined that the rotation speed N0 has not changed, and for example, the predetermined flag value is reset to 0. Then the routine is finished.

When the determination result of step S86 is affirmative, that is, when the deviation ΔN0 changes from a positive number to a negative number, the process proceeds to step S92 in FIG. Step S92 and Step S9
Step 4 is a step of waiting until the deviation ΔN0 changes from a negative number to a positive number. When the rotational speed N0 changes from decreasing to increasing and the determination result of step S92 becomes affirmative, step S9
6, the generation time interval of the pulse signal output from the N0 sensor 43 is stored as Tmax. Next, in step S98, it is determined whether or not the deviation ΔN0 is a negative number, and while monitoring the timer value Timer (step S100), the process waits until the deviation ΔN0 changes from a positive number to a negative number. Then, in step S98, the deviation ΔN0
If is changed to a negative number, the process proceeds to step S102, and the pulse signal generation time interval of the N0 sensor 43 at the time of the change is stored as Ta.

Whether the difference between the reciprocal values of the pulse signal generation time intervals Tmax and Ta thus obtained is larger than a predetermined value (for example, the value 20 corresponding to 50 rpm), that is, the above equation (A1) is It is determined whether or not it holds (step S
104). The relation of the previous expression (A1) is satisfied when the rotation speed N0
Is larger than a predetermined value (50 rpm), and in such a case, the value 1 is added to the stored value of the count value n5 and the value is stored and updated (step S106).
On the other hand, when the expression (A1) is not satisfied, the process returns to step S92 without changing the count value n5. In this way, the steps starting from step S92 are repeatedly executed again, and the number of fluctuations of the rotation speed N0 exceeding the predetermined value during one calculation time is counted. Then, in step S94
Alternatively, in step S100, when the timer value Timer has reached the predetermined value and one calculation time has elapsed, the process proceeds to step S108 in FIG.

In step S108 and the subsequent step S110, the count value n obtained as described above is used.
5 is a predetermined lower limit (eg, value 1) and upper limit (eg, 1)
It is determined whether or not the value is between the value 5). These determinations are to identify the frequency of vibration due to fluctuations in the rotational speed N0 as described above, and if the determinations in step S108 and step S110 are both negative,
It is determined that the rotation speed N0 corresponding to the direct coupling vibration has not changed (step S116). In this case, for example, the specific flag value described above is reset.

Steps S108 and S110
If the determination results of all are positive, it means that the vibration similar to the direct coupling vibration has occurred even if the slip direct coupling control is interrupted. In such a case, the stored value of the counter value n4 has the value 1 Is added and stored as a new stored value (step S112). Then, it is determined whether or not the updated value of the counter value n4 is a predetermined value (for example, the value 5) or more (step S114), and if the result of the determination is negative, the process returns to the step S82 and the count value is returned. n5 is reset, and the detection of the number of fluctuations of the rotation speed N0 during one calculation period is repeated. On the other hand, if the determination result in step S114 is affirmative, that is, if the vibration similar to the direct coupling vibration is continuously detected a predetermined number of times (5 times) after the slip direct coupling control is interrupted, the process proceeds to step S118, and the road surface It is determined that the rotation speed N0 is fluctuating due to the state or the like, and the above-mentioned specific flag is set, for example.

In the above-described embodiment, the presence or absence of the rotational fluctuation of the output shaft of the torque converter 20 is determined by detecting the rotational speed N0 of the transfer shaft 12 and the presence or absence of the fluctuation of the rotational speed N0. Needless to say, this is not done, and the rotation speed Nt of the turbine 24 may be directly detected. Further, the direct coupling mechanism is not limited to the damper clutch 26 of the above embodiment,
It goes without saying that various clutch devices can be applied.

[0041]

As is apparent from the above description, according to the direct-coupling control method for the automatic transmission of the present invention, when the internal combustion engine is operating in the predetermined operating range, the direct-coupling mechanism causes the slip amount to reach the predetermined value. In addition to controlling within the range, the rotation speed of the output shaft of the driving force transmission device is monitored, and when the rotation speed fluctuation of the output shaft exceeds the allowable range, the direct coupling mechanism is opened and the slip amount control is stopped. Detecting the rotational speed of the output shaft to determine whether the rotational fluctuation of the output shaft is within the allowable range, and if the rotational fluctuation of the output shaft still exceeds the allowable range, the slip occurs. The control of the slip amount is restarted, while the control of the slip amount is prohibited when the amount of the slip amount returns to the allowable range.

Therefore, the slip amount can be controlled within the predetermined value range by the direct coupling mechanism until the rotation fluctuation of the output shaft exceeds the allowable range due to the deterioration of the hydraulic oil of the driving force transmission device or the like. While the fuel efficiency can be improved, if the output shaft rotation fluctuation exceeds the allowable range,
It is possible to accurately identify whether this is due to deterioration of hydraulic oil or due to road surface conditions, etc. without providing a special sensor such as an acceleration sensor, and to prevent deterioration of hydraulic oil. As a result, it is possible to reliably prevent fluctuations in the output shaft rotation that exceed the allowable range, that is, direct coupling vibration.
It is possible to prevent a situation in which the passenger is uncomfortable due to the direct vibration.

[Brief description of 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 device 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.
FIG. 3 is a hydraulic circuit diagram showing a main part of 0 and a hydraulic control device.

FIG. 4 is a damper clutch 2 defined by an output shaft speed Nt of the torque converter 20 and a throttle valve opening θt.
It is a graph which shows the control area of No. 6.

5 is a diagram showing a mounting position of an N0 sensor 43 for detecting a rotational speed N0 of a transfer shaft 12 of the automatic transmission shown in FIG.

FIG. 6 is a graph showing the relationship between the generation state of an output pulse signal of the N0 sensor 43 and the time change of the rotational speed N0 of the transfer shaft 12 detected by the pulse signal.

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

FIG. 8 is a partial view of a flowchart showing a procedure (1) for detecting the presence or absence of fluctuations in the rotational speed N0 by the transmission control unit (TCU) 40.

FIG. 9 is likewise a partial view of a flow chart showing a procedure (1) for detecting the presence or absence of fluctuations in the rotational speed N0.

FIG. 10 is likewise a partial view of a flowchart showing a procedure (1) for detecting the presence or absence of a change in the rotation speed N0.

FIG. 11 is a partial view of a flowchart showing a procedure (2) for detecting whether or not there is a change in the rotation speed N0 after the slip direct coupling control is interrupted by the transmission control unit (TCU) 40.

FIG. 12 is also a partial view of a flowchart showing a procedure (2) for detecting the presence or absence of a change in the rotation speed N0 after the slip direct coupling control is interrupted.

FIG. 13 is also a partial view of a flowchart showing a procedure (2) for detecting whether or not the rotation speed N0 has changed after the slip direct coupling control is interrupted.

[Explanation 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 46 throttle opening (θt) sensor 50 hydraulic control device 52 damper clutch control valve 54 solenoid valve

Front page continued (72) Inventor Yoichi Furuichi 5-3-8 Shiba, Minato-ku, Tokyo Within Mitsubishi Motors Corporation (72) Inventor Kenji Suzuki 5-33-8 Shiba, Minato-ku, Tokyo Mitsubishi Motors Corporation Within the corporation (56) References JP-A-60-151457 (JP, A) JP-A-63-176865 (JP, A)

Claims (1)

[Claims] 1. An automatic transmission including a driving force transmission device having a direct coupling mechanism, which is interposed between an internal combustion engine and a gear transmission, and capable of controlling a slip amount of the driving force transmission device by the direct coupling mechanism. In the direct-coupling control method, when the internal combustion engine is operated in a predetermined operating range, the direct-coupling mechanism controls the slip amount within a predetermined value range and monitors the rotation speed of the output shaft of the driving force transmission device. Then
When the fluctuation of the rotation speed of the output shaft exceeds the allowable range, the direct coupling mechanism is opened to stop the control of the slip amount, and then the rotation speed of the output shaft is detected, and the fluctuation of the rotation of the output shaft is the allowable fluctuation. It is determined whether or not the value is within the range, and if the rotation fluctuation of the output shaft still exceeds the allowable range, the control of the slip amount is restarted, while if it returns to within the allowable range, the slip amount is returned. A direct connection control method for an automatic transmission, characterized by prohibiting the control of the automatic transmission.