JPS63270968A - Controller for automatic transmission - Google Patents

Abstract

PURPOSE:To improve travelability at time of turning or running on a curved road by installing a lockup clamping device which checks both engaging and releasing operations of a lockup clutch at a time when a curved road running state is detected by a curved road running detection device. CONSTITUTION:When a curved road running state is detected by a cirved road running detection device D, a lockup clutch A is clamped in a state at that time by a lockup clamping device E. Consequently, operation on an accelerator pedal and its return operation are carried out, so, even if a driving state is varied with these operations, both engaging and releasing operations of the lockup clutch A are not performed at all, so that such a possibility that these engaging and releasing operations of the clutch A are frequently carried out is thus avoided. With this constitution, any variation in driving force is avoided, whereby travelability at time of turning or running on a curved road is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an automatic transmission, and particularly to a control device for an automatic transmission equipped with a lock-up clutch that directly connects the input and output sides of a torque converter.

(Prior art) The automatic transmission installed in a vehicle sets a shift map in advance that uses vehicle speed and engine load as parameters, and compares this map with the actual driving condition B (vehicle speed and load). The system determines whether to shift up or down the gear position, and controls the gear position in accordance with the result of the determination. Further, this type of automatic transmission is sometimes equipped with a lock-up clutch that directly connects the input and output sides of the torque converter.

This lock-up clutch is released during operation in low-speed, high-load ranges, etc. and during gear changes, and utilizes the torque increasing effect of the torque converter and the absorption effect of shift shock.In operating areas where these effects are not required, the lock-up clutch is released. The input and output sides of the torque converter are directly connected to reduce deterioration in fuel efficiency caused by so-called slippage of the torque converter. Similarly to the above-mentioned gear position control, the engagement and release control of the lock-up clutch is also performed by setting engagement areas and release areas in advance as a map using vehicle speed and load as parameters, and then using this map and actual driving conditions. This is done by comparing the state.

According to Japanese Utility Model Publication No. 61-154126, a device has been proposed in which the speed change map is changed from a normal map to a turning map when the vehicle turns. This avoids shifting up the gear when the accelerator pedal is released or shifts the gear by shifting the gear line that makes up the gear shift map to the high speed side when transitioning from a straight-ahead state to a turning state. This allows engine braking to be applied while turning.

(Problem to be Solved by the Invention) By the way, according to the invention described in the above-mentioned publication, the shift up of the gear position is suppressed when turning by changing the shift map, but the lock-up map does not change when turning. Since the same does not change, the lock-up clutch will be engaged and disengaged as the operating conditions change during the turn. In particular, when driving on curved roads such as in mountainous areas, if you frequently operate the accelerator by returning the accelerator pedal when turning and depressing the accelerator pedal when driving straight,
As driving conditions change rapidly, the lock-up clutch must be engaged or disengaged each time, causing a problem in that the driving force fluctuates and good running performance cannot be obtained.

The present invention addresses the above-mentioned problems in vehicles equipped with automatic transmissions equipped with lock-up clutches, and aims to improve drivability when turning or traveling on curved roads.

(Means for Solving the Problems) In order to achieve the above object, an automatic transmission control device according to the present invention is characterized in that it is configured as follows.

That is, as shown in FIG. 1, there is a lock-up clutch A that directly connects the input and output sides of the torque converter, and the lock-up clutch A is engaged or released according to the operating state detected by the operating state detecting means B. In an automatic transmission equipped with a lock-up control means C, a curved road traveling detection means detects a curved road traveling state of the vehicle, and when a curved road traveling state is detected by the detection means (this It is provided with a lock-up fixing means E that prevents the lock-up clutch A from engaging and releasing the lock-up clutch A.The detecting means detects traveling on a curved road by determining, for example, the amount of accelerator depression.
It is possible to detect the steering wheel angle, straight-line traveling time, etc. as elements.

(Function) According to the above configuration, when the crooked road traveling state is detected by the crooked road traveling detection means, the lockup clutch is fixed in the state at that time by the lockup fixing means E. Therefore, even if the accelerator pedal is pressed down and released, and the driving conditions change accordingly, the lock-up clutch will not be engaged or released, and the clutch will not be engaged or released frequently. What will happen will be avoided.

(Example) Examples of the present invention will be described below. Note that this embodiment is for an automatic transmission used with an engine in which the opening degree of the throttle valve is electrically controlled.
The throttle control of the engine, the shift control and the lock-up control of the automatic transmission are performed in parallel.

As shown in FIG. 2, in the engine 1 according to this embodiment, the throttle valve 3 provided in the intake passage 2 is
It is designed to be opened and closed by an actuator 4 such as a motor. The automatic transmission 5 coupled to the engine 1 has a plurality of shift solenoids 61, 6□, 63 and a lock-up solenoid 7, and the hydraulic circuit is activated by turning ON and OFF the shift solenoids 61r, 6216s. is switched and a plurality of hydraulic engagement elements are selectively engaged, so that the transmission mechanism can be switched to a plurality of gear stages, and the lock-up solenoid 7 is turned ON and OFF to control the internal torque of the torque converter 8. A lock-up clutch 9 is configured to be engaged or released. Throttle control signals a,
A controller 10 is provided which outputs a shift control signal and a lock-up control signal C, and the controller 10 includes:
Accelerator sensor 1 that detects the amount of depression of the accelerator pedal
1, output signals d, e, f from the vehicle speed sensor 12 that detects the vehicle speed, and the steering angle sensor 13 that detects the steering wheel angle.
is now entered.

Next, the operation of this embodiment will be explained according to a flowchart showing the operation of the controller 10.

As shown in FIG. 3, this controller 10 performs a predetermined system initialization at the start of operation, and then controls the opening degree of the throttle valve 3 via the actuator 4 based on the signal a. , c control the gear position of the automatic transmission 5 and the lock-up clutch via the solenoids 61 to 63.7.

Here, to briefly explain the throttle control of the engine 1, this control electrically controls the opening degree of the throttle valve 3 according to a predetermined characteristic with respect to the amount of accelerator depression. By appropriately setting and changing the characteristics or gains of the gear, position, and vehicle speed according to other conditions, it is possible to always perform throttle opening control that matches the driving conditions.

On the other hand, the shift and lock-up control of the automatic transmission 5, which is a characteristic part of the present invention, is performed as follows according to the flowchart of FIG.

In this control, the controller 1o first inputs the accelerator depression amount α, vehicle speed V, and steering wheel steering angle θ based on the signals cj, e, and f from the accelerator sensor 11, vehicle speed sensor 12, and steering angle sensor 13, and , the value of the turning flag WF is determined (steps P1 to P4). This flag WF is set to "0" when the vehicle is traveling straight, and is set to "1" when the vehicle is turning.

Then, assuming that the vehicle was in a turning state at the time of the previous control, the controller 10 determines whether or not the steering wheel steering angle θ is less than 3 degrees even though WF=1. When the steering wheel is returned and the turning state shifts to the straight-ahead state, the timer value t and the turning flag WF are both reset to "0" (steps P5 to P7). Then, in the next control cycle, the controller 10 determines that since the turning flag WF is "0", the steering wheel steering angle θ is 5°.
Step P1 to determine whether or not the value exceeds ! +Pa)
, when θ≦5°, that is, when the straight-ahead state continues, 1 is added to the timer value t that was reset to “On” in step P6, and a check is made to see if this timer value t exceeds 10 seconds. If t>10 seconds, the straight running time T used in the fuzzy control described later is set to 10 seconds (steps P9 to P1t).On the other hand, by the time the timer value t reaches 10 seconds, the steering angle θ is When the angle exceeds 5°, that is, when the straight running state continues for 10 seconds and the vehicle shifts to the turning layer again, the timer value t at that time is set as the straight running time T, and the vehicle shifts to the turning state. Set the turning flag WF “
1” (steps P 8 , P 12+ P
13) *In this way, when the vehicle transitions from a turning state to a straight-ahead state, and then again to a turning state, the straight-ahead travel time T is set within a range of up to 10 seconds.

Next, when the controller 10 shifts to the turning state,
The degree of curvature of the traveling road is determined by fuzzy control using the accelerator depression amount α, the steering wheel angle θ, and the straight traveling time T determined as described above.

That is, first, the value of the accelerator depression amount α is applied to the horizontal axis of the membership characteristic diagram in FIG. 5, and two membership function values α1. While determining α2, these values αl and α2 are applied to the vertical axis of the membership characteristic diagram in FIG. Find in the range of 0 (step P 14 + PI 3) *In this case, the function value αi (i = 1.2, the same applies below)
is found from line P in FIG. 5, the corresponding level value Li is found from line P in FIG. 6, and when function value αi is found from line N in FIG. The value Li is determined from line N in FIG.

Next, in the same manner, the steering wheel angle θ and the straight running time T are applied to the horizontal axes of the membership characteristic diagrams shown in FIGS. Ship function value θ1. θ2 and T, ,T
2, and by combining and integrating these values, the integrated values w1 to w4 are obtained (steps P16 to P18
). Here, w1=θlXTl5w2°θ1 x'r2
, W3=θ2 x'r, , W4 =θ2×T2. Then, by applying these integrated values Wl to w4 to the vertical axis of the membership characteristic diagram in FIG. (Step P19). In this case,
If the function value θi is found from the line O in FIG. 7, and the function value Ti is found from the line L in FIG.
t and 'ri are line C in Fig. 7 and line L in Fig. 8, respectively.
and when the function values θi and Ti are the seventh
If the level value (lj) is determined from the line C1 in the figure and the line S in FIG. , function values θi and Ti are respectively on line 0 in FIG.
, when obtained from line S in Fig. 8, the integrated value wj
By applying to the line P in Figure 9, the level value ρ
j is required. In other words, as shown in the figure, the function value θ1 is from line 0 in FIG. 7, θ2 is from line C, and the function value T1
Assuming that T2 is obtained from line L in FIG. 8 and line S in FIG. 8, the integrated value wt(θ, x'r.

), W3(θ2XTI), W4(θ2XT2)
is applied to line N in FIG. 9 to obtain the level value ffl.

, 13. β4 is calculated respectively, and w2(θ1×T2
) is applied to the line P in FIG. 9 to obtain the level value ρ2.

Then, a function value α1. based on the accelerator depression amount α.
α2, the corresponding level value Ll+L2, and the integrated value Wl~W based on the steering wheel angle θ and the straight running time T.
4 and the corresponding level values jl to J24, the degree of curvature y of the running road is calculated according to the following equation (I) (step P20).

y= (Ll αl +L2 C2+!II Wl +
112w2 +, c, w3 +f4 W4) /
((21+722 +W+ +W2 +w3 +w4
) (I) This degree of curvature y is O1O~1
．． It varies within a range of 0, and the larger the value, the more significant the curvature of the running road is.

The controller 10 determines the degree of curvature y of the traveling road through the fuzzy control as described above, and then performs speed change control and lock-up control in accordance with this degree of curvature y.

In this control, the controller 10 sets a lockup release flag LUF, an overdrive (4th speed) release flag ODF, and a range flag SF.
After resetting to 0'', these flags are sequentially set to 1 according to the value of the degree of curvature y (steps P21 to
P27), that is, when the bending degree y is large (y≧0.8)
sets each of the above flags LUF, ODF, and SF to 1″
and when the bending degree y is "medium"(0,5≦y<0.
8) sets the lock-up release flag LUF and the overdrive release flag ODF to "1", and when the bending degree y is "small"(0,2≦y<0.5), the lock-up release flag is set to "1". Set only the flag LUF to "1n."

Incidentally, when the traveling road has almost no bend (y<0.2), each flag LUF, ODF, and SF are all set to "0°."

First, when the "2" range flag SF is "1", that is, when the bending degree y is "large", the "2" range map is used as the shift map used for determining the gear G, and the 3, 4
If the flexion degree y is not at least "large" (SF=O), the shift stage is determined from the accelerator depression amount α and the vehicle speed V using the normal map for the "D" range. G is determined (steps P291-P30).

In the latter case, the gear G is 4th (when overdrive is activated, an overdrive release flag ○
The value of DF is determined, and if 0DF=1, that is, the bending degree y is "medium", the variable speed G is set to 3rd speed (steps P31 to P33).

The controller 10 also controls the accelerator depression amount α and the vehicle speed V.
is compared with a preset lock-up map to determine whether the current operating state is in the lock-up clutch engagement region or disengagement region, and if it is in the engagement region, the value of the lock-up release flag LUF is determined. (Steps P34 to P36). When LUF=O, that is, when the traveling path is hardly curved, it is determined that the lock-up clutch should be engaged according to the above-mentioned lock-up map, whereas when LUF=1, that is, the degree of curvature y
is at least "small" or more, it is determined that the lock-up clutch should be released even though the operating state is in the engagement region of the lock-up map (step P37.
P3g). Then, according to the results determined as described above, control signals S and C are outputted to the shift solenoids 61 to 6S and the lockup solenoid shown in FIG. 2, respectively (Step P39).

In this way, when driving on a curved road (y≧0.2), the lock-up clutch is fixed in the released state regardless of the vehicle speed and the amount of accelerator depression, and the transition between the straight-ahead state and the turning state is achieved. Even if you operate the accelerator frequently depending on the
The lock-up clutch no longer engages and releases at a dizzying pace.

Furthermore, in this embodiment, as the degree of curvature of the road increases, the gear is fixed to the lower gear as described above, so that the engine brake is effectively activated when driving on a curvature. In combination with fixing the lock-up clutch described above, the running performance when traveling on a curved road is further improved.

In the above embodiment, the lock-up clutch is always kept in the released state when driving on a curved road so that sufficient starting torque can be obtained when transitioning from a turning state to a straight-ahead state by utilizing the torque increasing effect of the torque converter. However, the present invention is not limited to this, and it may be fixed to the state at that time when traveling on a curved road is detected. Further, according to this embodiment, the bending degree y is set to a predetermined value (0, 2), not only when traveling on a curved road where the straight-ahead state and the turning state are frequently repeated.
In this case, the lock-up clutch will be locked even during normal cornering.

(Effects of the Invention) As described above, according to the present invention, in a vehicle equipped with an automatic transmission equipped with a lock-up clutch, the lock-up clutch is fixed when turning or traveling on a curved road. When the vehicle is running, the lock-up clutch will not be engaged or released even if the accelerator is operated. As a result, fluctuations in the driving force are avoided, and drivability is improved when turning or traveling on a curved road.

[Brief explanation of the drawing]

Fig. 1 is an overall configuration diagram of the present invention, Figs. 2 to 9 show embodiments of the invention, Fig. 2 is a control system diagram, Fig. 3 is a flowchart showing the overall control operation, and Fig. 4 is a flowchart showing the overall control operation. The figure is a flowchart showing the speed change and lock-up control operations, and Figures 5 to 9 are characteristic diagrams for fuzzy control used to calculate the degree of curvature of the traveling road. 5... automatic transmission, 8... torque converter, 9...
... Lock-up clutch, 10... Lock-up control means, lock-up fixing means (controller), 11
．． 13... Curved road traveling detection means (accelerator sensor, steering angle sensor). Fig. 5 Accelerator stroke amount (%) Fig. 6 Fig. 7 Fig. 8 Fig. flS9

Claims (1)

[Claims] (1) A control device for an automatic transmission equipped with a lockup clutch that directly connects the input and output sides of a torque converter, and a lockup control means that engages and releases the lockup clutch depending on the operating state. , a curved road traveling detecting means for detecting a traveling state of the vehicle on a curved road, and a lockup fixing means for preventing engagement and disengagement of the lock-up clutch when the traveling state of the vehicle on a curved road is detected by the detecting means. A control device for an automatic transmission, characterized in that: