JPH02266157A - Hydraulic controller for automatic transmission - Google Patents

Abstract

PURPOSE:To avoid a large burden from the standpoint of control by compensating a line pressure being set by a line pressure control means, on the basis of a speed variation at a time when the specified time has elapsed since shift starting. CONSTITUTION:A passage 32 extending out of a pump P is connected to each of ports (a), (b), and the pressure is regulated by a pressure regulating valve 33 so as to cause it to become the specified line pressure. As the specified time since shift starting, for example, it can be set as a desired time hoping for shift completion, and if the line pressure is properly compensated, a speed variation at time when the specified time has elapsed comes to zero. When this speed variation is large enough as a positive or negative value, it means to be too early or too late, so that when shift is to early, it is regarded as too large in the line pressure, compensating it in a direction where this line pressure becomes lessened, as well as when the shift is too late the other way, compensating the line pressure in a direction where it is made larger. When this constitution, since monitoring time by a timer is determined uniformly as the preset time, a burden from the viewpoint of control will get off with smallness.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a hydraulic control device for an automatic transmission.

BACKGROUND OF THE INVENTION Automatic transmissions generally include a torque converter and a multi-speed gear mechanism coupled to the torque converter. By switching the operating state of a hydraulic friction element attached to the multi-speed gear mechanism, the power transmission path is switched, that is, the speed is changed.

The line pressure for the friction element described above has a large effect on shift shock. For this reason, the special public authority
As shown in Japanese Patent No. 83, there is a system in which the basic line pressure is corrected depending on the shift time, that is, whether the shift time is too long or too short.

(Problems to be Solved by the Invention) As mentioned above, although correcting the basic line pressure is advantageous from the viewpoint of rainproofing due to shift shock, it is difficult to easily correct the line pressure appropriately. This poses a major problem in practical application.

Considering the above-mentioned bulletin and coin from this point of view, it is necessary to constantly monitor the shift time, that is, the unspecified time from the start of the shift to the end of the shift, using a timer. This poses a large burden on control.

The present invention has been made in consideration of the following two circumstances. The purpose is to provide a hydraulic control device for a machine.

(Structure and operation of the invention) To achieve the above-mentioned purpose. The present invention has the following configuration. That is, as shown in the block diagram in FIG. 1O, by switching the operating state of the hydraulic friction element provided in the multi-speed gear mechanism, the power transmission path of the multi-speed gear mechanism is changed to perform the speed change. In the automatic transmission, the automatic transmission includes: a line pressure adjustment means for adjusting the line pressure to the friction element; a line pressure control means for controlling the line pressure adjustment means based on a predetermined line pressure characteristic set in advance; A rotation speed change rate detection means for detecting a change rate of the rotation speed on the input shaft side of the multi-stage gear mechanism, and a rotation speed change rate detected by the rotation speed change rate detection means at the time when a predetermined time has elapsed from the start of shifting. and line pressure correction means for correcting the line pressure set by the line pressure control means based on the line pressure control means.

The predetermined time from the start of the shift can be set, for example, as a desired time for completion of the shift. That is, it is preferable to set a desirable shift time in advance and make this set time coincide with the predetermined time. At this time, if the line pressure is appropriately corrected, the rotational speed change rate after a predetermined period of time will be approximately zero. On the other hand, when the rotational speed change rate is significantly large as a positive or negative value, the speed change is too V or too slow. If the gear shift is too fast, the line pressure is too high, and the line pressure should be corrected to decrease. Conversely, if the gear shift is too slow, the line pressure is too low, and the line pressure should be increased. All you have to do is correct it in the direction you want.

The above-mentioned set time can also be changed based on the driving state at that time, for example, by making it different when shifting from 1st to 2nd gear and from 2nd to 3rd gear. .

In addition, the rotation speed on the input shaft side of the multi-speed gear mechanism is as follows:
The engine rotation speed may be used, or if a torque converter is provided, the turbine rotation speed may not be used.

(Effects of the Invention) As described above, in the present invention, the time to be monitored by the timer is uniformly determined as a specific time set in advance, such as a predetermined time from the start of gear shifting, so that the burden on control is reduced. It's small.

In addition, a means for detecting the rotation speed on the input shaft side of a multi-speed gear mechanism is normally provided in a normal automatic transmission, so a special sensor for line pressure correction must be separately provided. is also no longer needed.

(Example) Examples of the present invention will be described below based on the attached drawings.

In FIG. 1, ``■'' is an engine, and the output of this engine 1 is transmitted via an automatic transmission 2 to drive wheels (not shown). The automatic transmission 2 includes a torque converter 3 having a lock-up clutch 3A, and a multi-speed float mechanism 4 connected to a turbine of the torque converter 3.

As is known, the multi-speed float mechanism 4 is horizontally shifted by a planetary gear mechanism, and in the embodiment has four forward speeds and one reverse speed. This multi-speed gear "F mechanism 4"
By changing the combination of engagement and disengagement of the plurality of hydraulic friction elements, the power transmission path is switched, that is, the speed is changed. Specifically, this speed change is performed by changing the combination of energization and demagnetization of a plurality of solenoids 6 incorporated in the hydraulic circuit for the friction elements. Similarly, the lock-up clutch 3A is activated by the solenoid 5 incorporated in the hydraulic circuit.
This is done by switching between 1% and demagnetization. Furthermore, as will be described later, by controlling the duty solenoid 7 incorporated in the hydraulic circuit, the magnitude of the hydraulic pressure supplied to the friction element and the lock-up clutch 3A can be adjusted.
That is, the line pressure is changed.

An example of the above-mentioned hydraulic circuit is shown in FIG. 2 with its essential parts simplified. In this Fig. 2, 31 is a manually operated manual valve, and by displacing its spool 31a, at least
And ko to N!・It is possible to take the following range positions: R (R) and R (Reverse). This manual valve 31
Boats a and b for supplying line pressure are opened, and boats c, d, and e, and drain boats `` and g'' are opened.

A passage 32 extending from the pump P is connected to the boats a and b, and the pressure in the passage 32 is regulated by a pressure regulating valve 33 so that it reaches a predetermined line pressure. That is, the amount of drain in the passage 32 is adjusted by the displacement position of the spool 33a of the pressure regulating valve 33. This pressure regulating valve 33 is connected to the passage 3
The line pressure is adjusted by the pilot pressure from the pilot passage 34 branched from 2, and the magnitude of this pilot pressure is adjusted by adjusting the drain amount of the pilot passage 34 by the iM solenoid 7.

More specifically, by changing the duty ratio for the solenoid 7, the pilot pressure is changed as shown in FIG. Then, the line pressure from the passage 32 is transferred to the passage 44.
It is constantly supplied to the torque converter 3 via. Note that the line pressure control will be described later.

Line pressure from the boat c is connected to a friction element 42 for backward movement via a passage 41, and an accumulator 43 is connected to the middle of this passage 41.

Further, a drain passage 4]a branched from the passage 41 is connected to the boat e. As a result, when the spool 3]a of the manual valve 31 is set to the backward range,
Boats a and C are communicated, and line pressure is supplied from boat a to friction gear 42 through passage 41, resulting in a reverse gear.

Furthermore, when the above-mentioned spool 3]a is set to a position other than the reverse range, the boat e is connected to the boat g, the pressure in the friction element 42 is drained, and the friction element 42 is released! be attacked.

When the manual valve 31 is set to the D range, boat b is connected to boat d. The line pressure from the boat d is constantly supplied to a forward selection friction element (forward clutch), which is not shown, and is appropriately supplied to a transmission friction element 46 via a shift valve 47. In FIG. 2, the shift valve 47 is a so-called 1-2 shift valve that changes gears between 1st speed and 2nd speed, and therefore, the friction element 46 functions between I speed and 2nd speed by engaging and releasing the friction element 46. This shows the gear that allows you to change gears between the two speeds. That is, by switching the shift valve 47, the friction element 4
Switching is performed between a state in which line pressure is supplied to the friction element 6 and the friction element 46 is fastened, and a state in which the friction element 46 is disengaged by draining the pressure within the friction element 46. Other such shift valves and friction elements are also provided, and the entire vehicle can be shifted to four forward speeds, but since these are already known, their illustrations are omitted. Of course, the switching position of the shift valve 47 can be changed by, for example, switching the pilot pressure supply mode using the solenoid 6 described above.

In FIGS. 1 and 2, U is a control unit configured using a microcomputer. A vehicle speed signal from a sensor 21, a throttle opening signal from a sensor 22, and an engine rotation speed signal from a sensor 23 are input to the control unit U.

The control unit IJ not only performs speed change control but also controls line pressure. First, shift control is performed by outputting a shift up signal or a shift down signal to the solenoid 6 based on predetermined shift characteristics, and an example of this shift characteristic is shown in FIG.

Next, the adjustment of line pressure by the control unit U will be explained. First, FIG. 4 shows the basic duty ratio DB for the line pressure adjusting solenoid 7, and in the embodiment, the pilot pressure for determining the line pressure is set using the throttle opening as a parameter. The characteristics of the basic duty ratio DB shown in the fourth section are stored in the ROM in the control unit U together with the above-mentioned respective speed change characteristics.

The basic duty ratio DB is corrected according to the rate of change in the engine speed after a predetermined period of time has elapsed from the start of the shift. This point will be explained with reference to FIG.
The figure shows an example of upshifting. In this Figure 6, α,
There are three manifestations, β and γ, and the overall outline will be explained by focusing on β shown by a solid line.

First, time t0 indicates the time when a shift command signal from the first speed to the second speed is output to the solenoid 6. Furthermore, for some time after this point, the rate of change in the engine speed remains almost the same as at 1 o'clock due to response delays and the like. At time 2, switching of the friction elements actually starts (at the start of gear shifting), and at this time the engine speed reaches a change point where it changes from an upward v# trend to a downward trend. After this, switching of the friction elements proceeds, and during this period the engine speed continues to decrease. The switching of the friction elements is completed at time 3, and at this time the engine speed reaches a change point where it changes from a downward trend to an upper limit trend.

Here, in this embodiment, at the start of gear shift (point 2 in Fig. 6)
07 seconds is set as the predetermined time. Then, the basic duty ratio DB is corrected so that the switching of the friction elements is completed exactly when this predetermined time has elapsed. From this viewpoint, each variation of α, β, and γ will be considered. First, σ indicates that an ideal gear shift has been performed, and the time has passed when the gear shift is completed, and at this time, the rate of change in the engine speed becomes approximately zero. In other words, when a,
This is when the line pressure setting is just right. On the contrary,
The case indicated by β is a case where the shift is completed well before the predetermined time has elapsed. When indicated by β, the line pressure is considered too high, and the duty ratio is corrected to increase in order to reduce the line pressure. Further, when indicated by γ, the shift is completed after a considerable time has elapsed from the predetermined time. When it is indicated by γ, the line pressure is considered to be too low, and the duty ratio is decreased in order to increase the line pressure.

Note: The gear shift is performed in any of the modes α, β, and γ. This can be identified by looking at the rate of change in engine speed at a given time. In other words, if the rate of change in the engine speed is almost zero, it means that an ideal gear shift has been performed (corresponding to α), and if this rate of change shows a positive value that is less than a predetermined value, the gear shift is completed. If the rate of change shows a negative value less than a predetermined value, it means that the shift was completed too late (corresponding to γ).

Section 7 and FIG. 8 are flowcharts showing specific control contents by the control unit U, and this flowchart will be explained below. Note that in the following explanation, P indicates a step.

First, in Pl of FIG. 7, signals from each sensor 21 to 23 are read, and then, in P2, the basic duty ratio DB is determined from the map shown in FIG. 4.

In P3, the learned value △Do determined as described below is corrected according to the gear shift mode and throttle opening.
A final learned value ΔDr is determined. In other words, the learning value △D
o is the predetermined throttle opening (35 to 40 as described later)
%) and the shift mode from 1st gear to 2nd gear as a standard, so when this standard is used, the modified 1st gear shift (or correction value ) to study this standard in 1st shift △
Do is modified.

At P4, the final duty ratio is calculated by adding the basic duty ratio D B at P2 and the final learned value ΔD at P3. Thereafter, the final duty ratio is output to the solenoid 6 at P5.

At P6, it is determined whether or not to perform a shift based on the shift characteristics shown in FIG. 5, and based on the result of this determination, a shift signal is output at P7.

At P8, it is determined whether or not it is time to shift from 1st speed to 2nd speed. If the 'sentence' in l) 8 is No, it will be returned as is, and if the judgment in P8 is YES,
Control is performed to determine the learned value ΔDl.

FIG. 8 shows the contents of FIG. 7 P9.

First, at P2], the throttle opening is 35 to 40%.
If it is confirmed that the range is within the range, the shift start timing, that is, the time t2 in FIG. 6 is detected in P22.

Then, in P23, when it is confirmed that 0.7 seconds have passed since this L2 time point, in P24, this 0.7 second has elapsed.
It is determined whether or not there is almost no change in the throttle opening after 7 seconds (time t2 in FIG. 6) (in the embodiment, this amount of change is set within 3 to 4%).

If the determination in P24 above is YES, in P25,
The rate of change XI of the engine speed at this time point t4 is calculated. After this, in P26, the rate of change xi is determined within a predetermined range, that is, a<XI<b (a, b are predetermined values, a<O
lb>o). Of course, the values of a and b define a setting range in which the rate of change x1 can be considered to be approximately zero, as is clear from the explanation of FIG. 6 above.

12 When the determination in P26 is No, it is determined in P27 whether or not the rate of change x1 is greater than the predetermined value. If the determination in P27 is YES, this corresponds to the case shown in β in FIG. 6, and the current line warehouse is too large. By adding (d>0), a new learning value ΔDo is determined. On the other hand, the determination on P27 is N.

In this case, the current line pressure is too small, which corresponds to the case shown in Fig. 6 γ, so the current learned value △ is
l) A new learned value ΔDo is determined by subtracting l+1 positive value ( ) from o.

New learning value determined in P28 or P29 above △
Do is stored and updated in P2O. Of course, the learned value ΔD is stored in this P2O.

is used for determining ΔD+ as explained in P3 of FIG.

If the determination in P26 is YES, the current line pressure is within the appropriate range, so the process is returned as is. Also,
P2] or P24, it is assumed that the learning conditions are not satisfied, and the process returns as is.

Modified Example FIG. 9 shows a modified example for determining the learned value ΔDo, and corresponds to the processing after P26 in FIG. 8. Among these, the learning value correction process in the case corresponding to β in Fig. 6 is performed in P41.
, P42, and P43. On the contrary,
The correction of the learned value △Do in the case corresponding to γ in Fig. 6 is based on the rate of change x2 of the engine speed at time t5 in Fig. 6, which is a predetermined time 0.3 seconds after t4 in Fig. That's what I do. This is done in consideration of the fact that in the case of γ, it may occur even when the line pressure is appropriate and the vehicle travels on a steeply ascending road.

That is, when determining the learning value in the case of γ, it is confirmed in P44 that 0.3 seconds have passed (confirmed at time t5 in Figure 6), and it is confirmed in P45 that there is almost no change in the throttle opening at this time. After that, the rate of change in engine speed at time ts×2 is calculated. After this, P4
At step 7, it is determined whether or not the value obtained by subtracting the change rate X2 at point 5 from the rate of change X2 at point 2+is greater than a predetermined value C. The determination of I) 47 boils down to:
From time L4 to time t, we will check whether the engine speed increases (decreases or not).
If the determination is YES, it is considered that the vehicle is traveling uphill, so the process returns without determining the learning value.

If the determination in P47 is No, it is determined in P4.8 whether the value obtained by subtracting x2 from the above X1 is smaller than O (in the case shown by γ in Figure 6, X] is negative). , and x2 is positive). When the determination in P48 is YES, in P49, the correction value d is calculated from the current learning value △Do.
A new learning value ΔDo is determined by subtracting . After this, in P2O, the new learning value determined in P49 is stored and updated.

In the above embodiment, the shift is started when the rotational speed starts changing, but the shift may be started when the shift command signal is generated (in this case, the predetermined time may be slightly modified in consideration of the response delay time).

[Brief explanation of drawings]

FIG. 1 is an overall system diagram showing one embodiment of the present invention. FIG. 2 is a simplified diagram of main parts showing an example of a hydraulic circuit of an automatic transmission. FIG. 3 is a diagram showing the relationship between the magnitude of pilot pressure and duty ratio for adjusting line pressure. FIG. 4 is a characteristic diagram showing basic line pressure settings. FIG. 5 is a diagram showing an example of speed change characteristics. FIG. 6 is a time chart for explaining the control contents of the present invention. 7 and 8 are flowcharts showing control examples of the present invention. FIG. 9 is a flowchart showing a modified example of Hill i wholesale according to the present invention. FIG. 10 is a block diagram showing the overall configuration of the present invention. 2 units 3 2 control units 1~: Engine 2 Automatic transmission: Torque converter multi-speed gear mechanism: Solenoid (for shifting): Solenoid (for adjusting line pressure): Sensor (vehicle speed) Sensor (throttle opening): Sen → No゛ (rotation speed): Manual valve: Passage (line pressure) Pressure regulating valve (for line pressure): Friction element (for speed change): Shift valve

Claims (1)

[Claims] (1) In an automatic transmission that changes gears by switching the power transmission path of the multi-speed gear mechanism by switching the operating state of a hydraulic friction element provided in the multi-speed gear mechanism, the friction element line pressure adjustment means for controlling the line pressure on the basis of predetermined line pressure characteristics; and line pressure control means for controlling the line pressure adjustment means based on predetermined line pressure characteristics; based on the rotation speed change rate detected by the rotation speed change rate detection means at the time when a predetermined period of time has elapsed from the start of gear shifting;
A hydraulic control device for an automatic transmission, comprising a line pressure correction means for correcting the line pressure set by the line pressure control means.