JPS6035582B2 - Automatic transmission lock-up control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a lock-up control device for a lock-up type automatic transmission among automatic transmissions.

Automatic transmissions generally increase torque from the engine,
Furthermore, a torque converter is included in the power transmission system to absorb torque fluctuations and achieve smooth power transmission, but this torque converter is designed to prevent slips between its input element (pump roller) and output element (turbine runner). Although it is easier to operate than a manual transmission, it has poor power transmission efficiency and tends to lead to poor fuel efficiency.

Therefore, the input and output elements of the torque converter are directly connected (
Lock-up type variable transmissions capable of lock-up are in practical use in some vehicles. By the way, in automatic transmissions, the torque converter is put into a lock-up state (sometimes only at a specific gear position) when the torque exceeds a set gear range (lock-up gear range) for each gear position (gear position). The backup area is as shown in FIG. 5, for example. This figure shows a shift pattern for upshifting of an automatic transmission with three forward speeds. are the lockup regions for the first far, second far, and third speeds, and the other regions are converter regions where input and output elements of the torque converter should not be directly connected. However, in a conventional lock-up control device that performs such lock-up control as it is, when the accelerator pedal is released while driving in the lock-up region A, B, or C, the dashed-dotted line in FIG. As shown in , the instant t. Thereafter, the lock-up signal continues to be output as long as it is in the lock-up region, so the torque converter is kept in the lock-up state. On the other hand, since the accelerator pedal is released from moment t onwards, the engine speed is reduced as shown by the dashed line in Figure 4, and at the same time it is reversely driven by the vehicle drive theory, so the output shaft torque is the same. Fourth
As shown by the dashed-dotted line x in the figure, it fluctuates so as to repeat increases and decreases for a certain amount of time T after the instant t. By the way, at this time, since the torque converter remains in the lock-up state as described above, it cannot absorb the torque fluctuation, and this is directly transmitted to the vehicle body, generating jerky vibrations and worsening ride comfort. Therefore, as shown by the two-dot chain line in Fig. 4, it was considered to keep the torque converter in the converter state by blocking the output of the lock-up signal as long as the accelerator pedal is released from the moment t when the accelerator pedal is released. . In this case, the engine speed outside the torque converter is reduced as shown by the two-dot chain line in Fig. 4, and the above fluctuation x in the output shaft torque is absorbed and changed as shown by y in Fig. 4. This can prevent the occurrence of jerky vibrations. However, after the output shaft torque fluctuation x that causes this jerky vibration is attenuated (after time T has elapsed), the torque converter no longer generates the vibration. Even though it is possible to put the torque converter in the lock-up state, because it was kept in the converter state, the output shaft torque reached the value shown by the two-dot chain line in Fig. 4 after time T had elapsed, and when the torque converter was placed in the lock-up state. The effectiveness of the engine brake deteriorates by the difference ΔTr from the output shaft torque z, which is undesirable. In view of the above, the present invention prevents the torque converter from being locked up during the time period after the accelerator pedal is released until the output shaft torque fluctuation attenuates. In addition to preventing the occurrence of jerky vibrations, the torque converter can then be locked up and the accelerator pedal is released in the lock-up area, allowing engine braking to work effectively while driving, thereby solving the problems with conventional devices mentioned above. The present invention attempts to provide a lock-up control device for an automatic transmission.

Hereinafter, the present invention will be explained in detail with reference to illustrated embodiments.

FIG. 1 shows an example of a lock-up control device of the present invention configured to be used in an automatic transmission having the shift pattern and lock-up region shown in FIG. shift switches, these switches are incorporated into the 1-2 shift valve and the 2-3 shift valve of the automatic transmission, respectively, so that the respective valve spools are closed when in the downshift position and opened when in the upshift position; do.

In addition, switches 1 and 2 are connected to the power supply +V via resistors 3 and 4, respectively.
and output shift valve signals S, v, and S2v whose levels change as shown below when opened and closed. That is,
When the automatic transmission selects the gear position of 1st gear, 1
Since the valve spools of the -2 shift valve and the 2-3 shift valve are both in the downshift position, closing both shift switches 1 and 2, these switches lower the corresponding shift valve signals S, v, and S2v, respectively. L) level. Also, the second
When the far gear position is selected, only the valve spool of the 1-2 shift valve is in the upshift position and opens shift switch 1, so this switch shifts; - Valve signals S, v are set high ( H) level. Furthermore, when the third far gear position is selected, the valve spool of the 2-3 shift valve also goes to the upshift position and opens shift switch 2, so this switch also sets the shift valve signal Sw to H level. Eggplant. In other words, at each gear position, the shift valve signals S, v,
The combinations of Sw levels are as follows. Both shift valve signals S, v, and S2v are input to the gear position determination circuit 5, and this circuit determines the current gear position from the combination of the levels of the signals S, v, and Sw, and determines whether the gear position is at the first far position. If so, set the 1st speed signal S, to day level, and if 2nd speed, set the 2nd speed signal to H.
In the case of the third far signal, the third far signal S3 is set to the H level, but these signals S, S2, and S3 are otherwise kept at the L level.

The shift valve signals S, v, and S2v are also supplied to a speed change detection circuit 6, which includes an edge trigger circuit that detects the rise and fall of the shift valve signals S and v, and a rise and fall of the shift valve signal S2v. These edge trigger circuits each output a normal level signal, but when the corresponding shift valve signal S, v or Sw changes from L level to H level or from H level to L When switching to level, that is, when the valve spool of the corresponding shift valve moves from the downshift position or upshift position to the upshift position or downshift position to perform automatic gear shifting, a negative polarity trigger pulse P is output. The pulse width is made to correspond to the time required for the automatic transmission to actually change gears.

7 is a vehicle speed sensor that supplies a vehicle speed signal V corresponding to the vehicle speed to a vehicle distance comparator circuit 8, and this circuit 8 locks up the input vehicle speed signal V to vehicle distance sensors V, , V2, and V3 (all of which are fifth (see figure), when the vehicle speed becomes higher than the lock-up vehicle distance V, the H level signal is sent from the corresponding gate a.
Furthermore, when the vehicle speed becomes higher than the lock-up vehicle distance V2, an H level signal is also output from the corresponding gate b, and when the vehicle speed becomes higher than the lock-up vehicle speed V3, an H level signal is also output from the corresponding gate a. do.

These signals are the signal S. , S2, and S3 are supplied to the AND gates 10/12 of the lock-up determination circuit 9.
The AND gate 10 performs the logical product of the signal output from the gate a of the vehicle distance comparator circuit 8 and the 1 distance signal S, and determines the first speed lockup region A in FIG. 5 where both of these signals become H level. outputs an H level signal. AND gate 11
is the signal output from gate b of vehicle speed comparison circuit 8 and 2
A logical product with the far signal S2 is taken, and an H level signal is output in the second far lockup region B in FIG. 5 where both of these signals become H level. Further, the AND gate 12 performs a logical product of the signal output from the gate c of the vehicle distance comparator circuit 8 and the 3rd speed signal S3, and the third distance lockup region C in FIG. outputs an H level signal. In this way, AND gate 1 0, 1 1 is 1
If an H level signal is output from even one of the lockup regions A, B, or C shown in FIG.
A lock-up permission signal S at the daytime driving level is supplied to one input terminal of the AND gate 14. AND
The output terminal of gate 14 is Darlington transistor 15
The lock-up solenoid 16 is connected to the 10V power supply through the collector-emitter path of the transistor.

It is assumed that the lock-up solenoid 16 puts the torque converter of the automatic transmission in the lock-up state when it is energized, and puts the torque converter in the converter state when it is de-energized. In the present invention, an idle switch 17 is provided,
This switch is, for example, a normally open switch provided in the link system so as to close only when the accelerator pedal is released.

One end of the idle switch 17 is grounded, and the other end is connected to the power supply +V via a resistor 18. Thus, the idle switch 17 is opened during normal driving when the accelerator pedal is depressed, and the idle signal S, is set to the daily level by the power supply +V, and closed when the accelerator pedal is released, and the idle signal S, is set to the L level. The idle signal S, is supplied to an idle detection circuit 19, and this circuit 19 normally keeps the output signal to the AND gate 14 at H level, but when the idle signal S, falls, that is, when the accelerator pedal is released, the output is The signal is changed to L level, and if the accelerator pedal continues to be released, this L level is maintained for a predetermined time.

Note that this predetermined time is the time T required for the output shaft torque fluctuation caused by the release of the accelerator pedal to attenuate.
(See Figure 4). In the above configuration, the automatic transmission is not shifting, the shift detection circuit 6 is not outputting the negative pulse signal P, and the driver has not released the accelerator pedal. When the set time T has elapsed, the signals sent from the speed change detection circuit 6 and the idle detection circuit 19 to the AND gate 14 are at H level, so lock-up control as shown in FIG. 5 is executed. That is, lockup area A, B or C in FIG.
As mentioned above, AND gates 10 and 11 are
Alternatively, an H level signal is output from 12, and this signal is supplied to AND gate 14 via OR gate 13.

At this time, the AND gate 14 supplies the H level signal as the lockup signal SL/u to the transistor 15, making it conductive. This is due to lock-up solenoid 16
is energized by the power supply +V, and the torque converter can be brought into a predetermined lock-up state while the vehicle is running in the lock-up region. Furthermore, while driving in a region other than the lock-up area shown in FIG. 5, the AND gate 10 is
Since no H level signal is output from any of the circuits 1 to 12, the AND gate 14 keeps the lockup signal SL/u at the L level and makes the transistor 15 non-conductive, so the lockup solenoid 16 is not connected. Therefore, the torque converter can be brought into the converter state as required while driving outside the lock-up region.

On the other hand, while the automatic transmission is in a gear shifting operation and the gear shift detection circuit 6 is outputting the negative polarity trigger pulse P, as described above, this is supplied to the AND gate 14, and this AND gate is used as a lock-up signal during this period. SL/u is set to H level to prevent the torque converter from being locked up.

Therefore, when an automatic transmission changes gears on a shift line in which the lock-up regions of each shift position are adjacent to each other in a relatively large throttle opening range as shown in FIG. 5, the torque converter is during the pulse width time of the signal P,). Even in the backup region, the lock-up can be temporarily released and the converter state can be returned to, thereby preventing a shift shock from increasing. Further, when the driver releases the accelerator pedal and continues this release for more than the predetermined time T, the idle detection circuit 19 supplies an L level signal to the AND gate 14 during the predetermined time instant after the accelerator pedal is released, as described above. Similarly, during this time, the lock-up signal SL/u cannot be set to H level, and the torque converter is disabled. backup is prevented. Therefore,
When the accelerator pedal is released in this way while driving in the lock-up region, the lock-up signal SL is activated for a time T from the instant t when the accelerator pedal is released, as shown by the solid line in FIG.
/u is set to L level, and during this time the torque converter is returned to the converter state. Therefore, the torque converter reduces the engine speed during time T as shown by the solid line in FIG. 4, absorbs the output shaft torque fluctuation x, and changes it as shown by the solid line y in FIG. It is possible to prevent the vehicle from causing rattling vibrations. After the moment shown in FIG. 4 when the output shaft torque fluctuation is attenuated as time T elapses and rattling vibrations no longer occur, the idle detection circuit 19 detects the AND gate 14 as described above even if the accelerator pedal is released. Since the output signal to the lockup signal SL/u is changed to H level and the lockup control is returned to the normal control, the lockup signal SL/u becomes H level as shown by the solid line in FIG. to lock up the torque converter.

For this reason, the torque converter increases the engine speed after instantaneous hot water t, as shown by the solid line in Figure 4, and then decreases it again, and also changes the output shaft torque as shown by the solid line z in Figure 4. This makes it possible to improve the effectiveness of the engine brake by the amount of torque ΔTr compared to when the torque converter is left in the converter state. Incidentally, in FIG. 4, the output shaft torque fluctuation x becomes larger as the gear position becomes lower, and the time T required for attenuation of the torque fluctuation becomes longer as the gear position becomes lower.

From this, as shown by the solid line in FIG. 4, it is preferable to determine the time T during which the lock-up signal SL/u should be brought to the L level for each gear position, and FIG. Here is another example. In this example, an idle detection circuit indicated by 20 is used in place of the idle detection circuit 19 in FIG.
1 to 23 and an AND gate 24. Circuit 21~
In addition to the idle signal S, 23 is input with the corresponding 1st far signal S, 2nd speed signal S2, and 3rd far signal S3, and when the idle signal SI falls due to release of the accelerator pedal, it becomes H level. signal S. , S2, the idle detection circuit 21, 22 or 23 receiving S3 changes the output signal level to L level, and if the accelerator pedal continues to be released, this L level is maintained for a predetermined time determined for each gear position. shall be maintained. Note that these predetermined times differ depending on the gear position, but are made to correspond to the time required for output shaft torque fluctuations caused by release of the accelerator pedal to attenuate. In the configuration of this example, When the accelerator pedal is released while driving in the backup area, circuits 21 (in 1st gear), 22 (in 2nd gear), or 23 (in 3rd gear) are activated depending on the current gear position.
2) is outputting the L level signal during the occurrence of the output shaft torque fluctuation caused by the release of the accelerator pedal to the AND gate 2.
4, and from this AND gate 1 4
Since the signal directed to the torque converter is kept at L level during this period to prevent lock-up of the torque converter, the object of the present invention can be achieved in the same manner as in the above-mentioned example. Furthermore, in this example, since the lock-up prevention time can be determined for each gear position, it is possible to accurately correspond to the output shaft torque fluctuation generation time, which differs for each gear position, and the effect of the above-described example can be further enhanced. It can be played noticeably. Note that automatic transmissions are generally the first
Because the long drive power transmission train includes a one-way clutch through which power is transmitted for the first long drive, even if the accelerator pedal is released, the reverse drive force from the vehicle drive wheels is interrupted by the one-way clutch. Because it is not transmitted to the engine,
Normally, the output torque does not fluctuate as described above and cause jerky vibrations. Therefore, in the case of such an automatic transmission, the lock-up release function as in the present invention is not required only at the first far gear position, and in the example of FIG.
The distant idle detection circuit 21 can be omitted. The time T required for the torque fluctuation to attenuate becomes longer as the speed increases.

//From this, as shown by the solid line in Fig. 4, the time T for which the lock-up signal SL/u should be set to L level should be changed depending on the distance of the vehicle, and Fig. 3 shows the horizontal Further examples of the present invention will now be described. In this example, an idle detection circuit 25 is used in place of the idle detection circuit 19 in FIG. Further, another gate d is set in the vehicle speed comparison circuit so that a time/date level signal is outputted from the gate when the vehicle speed signal V becomes equal to or higher than the set vehicle speed V4. The set vehicle speed V4 is set to be equal to or higher than the third distance lockup vehicle distance V3 (see FIG. 5), and is set to a vehicle speed at which it starts to take a relatively long time to attenuate the output shaft torque fluctuation. The circuits 26 and 27 commonly receive the idle signal S, and also receive a signal from the gate d, but the signal going from the gate d to the circuit 26 is NO.
It is inverted and supplied by the T gate 29. The circuit 26 can be triggered by an H level signal obtained by inverting this signal with a NOT gate 29 when the signal from the gate d becomes an L level when the vehicle is far away at a low speed where V<V4, and the accelerator is activated. When the idle signal SI falls due to release of the pedal, the output signal is changed to L level, and if the accelerator pedal continues to be released, this L level is maintained for a predetermined time for low vehicle distance. Further, the circuit 27 can be triggered by this signal when the vehicle speed is VZV4 and the signal from the gate d becomes H level, and outputs an output signal when the idle signal S falls due to release of the accelerator pedal. is changed to L level, and if the accelerator pedal continues to be released, this L level is maintained for a predetermined time for high vehicle distance driving. The set times for low vehicle speed and high vehicle speed differ depending on whether the vehicle is running at low speed or high speed, but are made to correspond to the time required for output shaft torque fluctuations caused by release of the accelerator pedal to attenuate. In the configuration of the present example, when the accelerator pedal is released while driving in the lock-up region, the circuit 26 or 27 operates depending on whether the vehicle speed is V<V4 or VZV4, while the output shaft torque fluctuation caused by the release of the accelerator pedal is occurring. L
Since the level signal is supplied to the AND gate 28 and the signal from the AND gate to the AND gate 14 is kept at L level during this period to prevent lock-up of the torque converter, the object of the present invention is achieved in the same manner as in each of the above-mentioned examples. be able to.

Moreover, in this example, since the lock-up prevention time can be determined for each vehicle distance range, this can be adjusted to the different output shaft torque fluctuation occurrence times depending on the vehicle speed, and the effect of the embodiment shown in FIG. 1 can be further improved. It can be made into something remarkable. In addition, the second
In the embodiments shown in Fig. 3 and Fig. 3, the lock-up prevention time is determined for each gear position and vehicle speed range, respectively. It is also possible to easily determine this, and in this case, the accuracy of control is further improved.

Thus, the lock-up control device of the present invention, as described above,
When the accelerator pedal is released while driving in the lock-up region, the torque converter is unlocked for a predetermined period of time, and then returns to the lock-up state.
The output shaft torque fluctuation that occurs for a while after the accelerator pedal is released can be absorbed by the converter state torque converter to prevent the occurrence of rattling vibrations. Brake effectiveness can be made sufficient.

Furthermore, if the structure shown in FIG. 2 or 3 or a combination thereof is used, the lock-up release time can always match the attenuation time of the torque fluctuation that changes for each gear position and vehicle telescope. The above-mentioned effects can be exhibited even more significantly over the entire operating range.

[Brief explanation of the drawing]

FIG. 1 is an electronic circuit diagram showing an example configuration of the lock-up control device of the present invention, FIGS. 2 and 3 are electronic circuit diagrams showing two other examples of the present invention, and FIG. 4 is a lock-up control device according to the present invention. FIG. 5 is a flowchart showing the up-control operation in comparison with that of a conventional device, and FIG. 5 is a shift pattern diagram for up-shifting of an automatic transmission illustrating a general lock-up region. 1...1-2 shift switch, 2...2-3... ...Shift switch, 5...Gear position discrimination circuit, 6.
...speed change detection circuit, 7...vehicle speed sensor,
8...Vehicle speed comparison circuit, 9...Lockup determination circuit, 14. ...AND gate, 15...
...Darlington transistor, 16...Lockup solenoid, 17...Idle switch, 19,20
, 25... Idle detection circuit, 21... Idle detection circuit for 1st speed, 22... Idle detection circuit for 2nd speed, 23... Idle detection circuit for 3rd speed, 24
, 28...AND gate, 26...Low speed idle detection circuit, 27...High speed idle detection circuit, 29...NOT gate. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Scope of Claims] 1. In a lock-up automatic transmission that includes a torque converter in the power transmission system and can put the torque converter into a lock-up state in which its input and output elements are directly connected by means of a lock-up signal, when the accelerator pedal is released. A lock-up control device for an automatic transmission, characterized in that the output of the lock-up signal is blocked for a predetermined period of time, and after the predetermined period, the output of the lock-up signal is permitted even if the accelerator pedal is released. 2. The lock-up control device for an automatic transmission according to claim 1, wherein the predetermined time varies depending on the gear position. 3. A lock-up control device for an automatic transmission according to claim 1 or 3, wherein the predetermined time varies depending on vehicle speed.