JPH08159268A - Gear shift control device for automatic transmission for vehicle - Google Patents

Abstract

PURPOSE: To improve acceleration ability and fuel consumption by a method wherein the engaging and disengaging state of a lockup clutch is detected and a shift is controlled by employing a map which is differed with a time during release of a lockup clutch and a time during engagement of a lockup clutch. CONSTITUTION: An automatic transmission comprises a torque converter 1 with a lockup clutch 7; a three-shift part being a main shift part; and an overdrive 3 being an auxiliary shift part. A given shift speed is established in such a way that an oil pressure fed from an oil pressure control device 10 is controlled by a solenoid valve. In the shift control, two kinds of maps responding to the engaging and disengaging state of the lockup clutch 7 are provided as a control map. During release of the lockup clutch, a first map having a shift up line and a down shift line set to the higher throttle opening side than the shift up line is employed. During lockup clutch engagement, the second map set to the relatively lower throttle opening side is employed to effect shift control.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for controlling a shift of an automatic transmission for a vehicle, and more particularly to a shift control device for an automatic transmission having an overdrive portion.

[0002]

2. Description of the Related Art Conventionally, in order to improve quietness and fuel efficiency during high-speed running, an automatic transmission configured so that an overdrive stage having a gear ratio smaller than "1" can be set is widely used, and a torque converter is used. In order to correct the deterioration of fuel economy due to the slip of the lockup clutch, a lockup clutch that mechanically directly connects the input element (front cover) and the output element (turbine runner) has been widely used. The overdrive stage in this type of automatic transmission is designed to be electrically controlled because it is necessary to be able to release it artificially.This is because the forward stage is governor pressure according to the output shaft speed. The same applies to a hydraulic automatic transmission that is controlled based on the above. That is, in the conventional hydraulic automatic transmission, the solenoid valve is controlled by using the throttle opening representing the engine load and the output shaft speed or the vehicle speed as parameters, and for example, the shift between the third speed and the fourth speed is controlled. There is.

On the other hand, since the lockup clutch is a clutch that mechanically directly connects the input element and the output element of the torque converter, the vibration from the engine is also transmitted when the lockup clutch is engaged. Moreover, since the input element and the output element rotate at the same rotational speed, the torque amplifying action is lost. Therefore, in general, the lock-up clutch is normally engaged at a speed higher than a predetermined speed such as the highest speed and at a vehicle speed higher than the predetermined speed. Such control is also performed in the hydraulic automatic transmission in the same manner. Specifically, the lockup signal valve is operated by the governor pressure that is a pressure corresponding to the output shaft speed,
Further, the lockup relay valve is operated by the output pressure to engage / disengage the lockup clutch (ON / OFF).
OFF) is controlled.

An automatic transmission for performing this type of control is described in, for example, "Toyota Serviceman Technology Acquisition Manual, Third Step" (issued by Toyota Motor Corporation in October 1984). In this automatic transmission, the vehicle speed is approximately 57km in the 4th speed (overdrive (O / D) cut released).
/ H or more, the lockup clutch is engaged (ON), and the vehicle speed is approximately 50 km in the 4th speed state.
The lock-up clutch is disengaged (OFF) when the pressure falls below / h.

The conventional automatic transmission described above electrically controls the O / D cut, and an example of the control map is shown in FIG. This is a schematic view showing a part of the shift map of the automatic transmission and the control map of the lockup clutch, and the solid line in the upper right corner is O.
/ D cut execution line, and the broken line set on the lower throttle opening side is the O / D cut release line. Therefore, by changing the throttle opening so as to cross the O / D cut execution line from the lower side to the upper side, the O / D cut (downshift from the fourth speed to the third speed) is executed. On the other hand, the throttle opening changes so that it crosses the O / D cut release line from the upper side to the lower side.
Switch to state (upshift from 3rd speed to 4th speed)
Is executed.

On the other hand, when the vehicle speed changes together with the O / D cut control based on such a change in the throttle opening, the lockup clutch is turned ON / O due to the change in the governor pressure.
FF (engagement / release) control is performed, and a map for this control is shown by the ON line and the OFF line in FIG. That is, as the vehicle speed increases so as to cross the ON line, the lockup clutch is engaged, and vice versa.
The lockup clutch is released when the vehicle speed decreases so as to cross the FF line. In order to prevent hunting, hysteresis is set between the ON line and the OFF line. As described above, the map for O / D control is such that the higher the vehicle speed is, the higher the throttle opening side is,
The region is set. This means that if the vehicle speed is high (that is, the engine speed is high), the muffled noise does not become loud even at high throttle opening, and the acceleration is particularly insufficient. Because there is no.

[0007]

However, when the accelerator pedal is depressed to accelerate and the throttle opening is increased while the vehicle is traveling at the fourth speed, which is the O / D state, the traveling state becomes the third state shown in FIG. By entering the speed range, the control of O / D cut is executed to downshift to the third speed. As a result, when the gear ratio is increased, sufficient acceleration force is obtained, and when the vehicle speed is increased and the accelerator pedal is returned to reduce the throttle opening, the throttle opening is reduced to the fourth speed range in the traveling state. Upon entering, control for O / D cut cancellation is executed, and upshift is made to the fourth speed. Further, the lockup clutch is engaged as the vehicle speed increases. That is, the reduction of the gear ratio due to the upshift and the cancellation of the torque increasing function of the torque converter due to the engagement of the lockup clutch occur simultaneously.

In that case, in the above-mentioned conventional control device,
In the 4th speed state of lockup ON, the map for O / D control is uniformly set to rise to the right,
This is achieved before the vehicle speed has sufficiently increased, resulting in a state of insufficient acceleration force, which causes the accelerator pedal to be depressed again, which causes a downshift to the third speed. In such a situation, the throttle opening is increased in the lockup ON state to downshift to the third speed, and then the throttle opening is decreased to the lockup ON O / D state (the fourth speed). The same is true when returning, and due to lack of acceleration,
The accelerator pedal is depressed to execute the downshift to the third speed.

As described above, in the conventional shift control device, O /
Since the throttle opening condition for controlling D-cut is the same regardless of ON / OFF of the lockup clutch, after executing O / D-cut to accelerate,
When the throttle opening is narrowed to release the O / D cut control, the acceleration force is insufficient and the O / D cut control is required again, which causes a problem such as a so-called busy shift.

The present invention has been made in view of the above circumstances, and provides a gear shift control device capable of improving acceleration performance and fuel consumption by performing overdrive control suitable for lockup ON and OFF. It is intended to be provided.

[0011]

In order to achieve the above-mentioned object, the present invention is switched between a lockup clutch for directly transmitting torque between an input element and an output element in a torque converter, and a high-low two-stage. A shift control device for an automatic transmission, comprising: an overdrive part; and an overdrive control means for controlling switching of the overdrive part to a high speed stage or a low speed stage based on a map using a value representing a traveling state as a parameter, Lockup detection means for detecting the engaged / released state of the lockup clutch, and as the map, when the lockup clutch is released, the upshift line and the higher throttle opening side than the upshift line are set. Adopting the first map with the downshift line and the lockup clutch engaged. In this case, a second map having a downshift line set between the upshift line and the downshift line and an upshift line set on the lower throttle opening side of the upshift line is adopted. A map switching means is provided.

[0012]

The shift control device according to the present invention has, as maps for controlling the overdrive portion, a map used when the lockup clutch is engaged and a map used when the lockup clutch is released. There are two types of maps. The lockup detecting means detects the engaged / disengaged state of the lockup clutch,
Based on the detection result, the map switching means selects a map suitable for the engagement / disengagement state of the lockup clutch, and controls the overdrive unit according to the map.

The maps used in the state in which the lockup clutch is engaged are compared with the maps used in the state in which the lockup clutch is released. Therefore, when the throttle opening is increased in the lockup state, the overdrive state is released (O / D cut) relatively early, and the gear ratio is increased to ensure acceleration. . On the other hand, when the lockup clutch is released, a certain map is used as the overdrive range up to the high throttle opening side.Therefore, the torque amplifying action of the torque converter provides the acceleration force and delays the downshift. It suppresses an increase in engine speed and improves fuel economy. Furthermore, after downshifting by controlling overdrive cut for acceleration, if you enter the lockup area by increasing the vehicle speed, changing the map used will make it difficult for upshifting due to overdrive cut cancellation, so acceleration Shortages are avoided. And the map downshift line used in the lockup state is set to a higher throttle opening side than the map upshift line used in the state where the lockup clutch is released. Hunting is prevented.

[0014]

EXAMPLES The present invention will now be described based on examples. The automatic transmission shown in FIG. 1 includes a torque converter 1 with a lock-up clutch, a third speed shifting portion 2 as a main shifting portion, and an overdrive (O / D) portion 3 as a sub shifting portion.
It has and. The torque converter 1 is conventionally known, and a turbine runner 6 is arranged so as to face a pump impeller 5 integrated with a front cover 4, and a lock that selectively engages with the front cover 4. The up clutch 7 is connected to the turbine runner 6. Reference numeral 8 indicates a stator, and this stator 8
Is supported by a predetermined fixed portion via a one-way clutch 9.

The third speed transmission unit 2 is mainly composed of two sets of planetary gear mechanisms and frictional engagement devices such as a plurality of clutches and brakes, although the details thereof are omitted. It is configured such that three forward gears and one reverse gear can be set. The O / D section 3 is arranged on the output side of the third speed transmission section 2 and is mainly composed of a set of planetary gear mechanism, clutch and brake, and has a low speed stage in a direct connection state and a high speed stage in a speed increasing state. And can be set. These 3rd speed transmission section 2 and O / D
The part 3 has a conventionally known structure.

The shift control in this automatic transmission is mainly performed by a governor which controls the shift valve in the hydraulic control device 10 so that the throttle pressure is a pressure corresponding to the throttle opening and the output shaft rotational speed (that is, the vehicle speed). It is executed by switching operation by pressure and by supplying and discharging hydraulic pressure to the hydraulic servo mechanism of each clutch and brake by the shift valve. Further, the engagement / disengagement control of the lockup clutch 7 is performed by operating a lockup signal valve (not shown) by governor pressure, and the hydraulic pressure output from the lockup signal valve is sent to a lockup relay valve (not shown). It is executed by switching the supply / discharge direction of the hydraulic pressure to the lock-up clutch 7. A conventionally known mechanism can be adopted as a mechanism for controlling the governor valve (not shown) that generates the governor pressure and the lockup clutch 7, and a detailed description thereof will be omitted.

The control of the O / D section 3 is executed by the hydraulic pressure sent from the hydraulic control device 10 as in the case of the third speed transmission section 2, and the hydraulic pressure therefor is electrically supplied by a solenoid valve (not shown). Controlled. Therefore, an electronic control unit (T-ECU) mainly composed of a microcomputer
11 is provided. The electronic control unit 11 includes a vehicle speed S from an electronic control unit (E-ECU) 12 for the engine.
PD and throttle opening TA are communicated as control data. Then, the electronic control unit 11 outputs a signal to the solenoid valve based on a control map provided in advance and the input data, and controls the O / D unit 3 to a high speed stage or a low speed stage.

As the control map, two types of maps are provided according to the engagement / release states of the lockup clutch 7, one example of which is schematically shown in FIG. This map shows the vehicle speed SPD on the horizontal axis and the throttle opening TA on the vertical axis.
And the O / D area (O / D cut release area: fourth speed area) and the non-O / D area (O / D cut area: third speed area) are set by these two parameters. is there. The map indicated by reference sign A is a map adopted when the lockup clutch 7 is released (L / U OFF), and the map indicated by reference sign B is engaged by the lockup clutch 7 (L / U ON). ) This is a map that is adopted when doing.

The maps A and B will be briefly described. Both of them have upshift lines Au and Bu and downshift lines Ad and Bd, and the lower side of these lines is an O / D region and the upper side is. It is an O / D cut area. The upshift lines Au and Bu are set to a lower throttle opening side than the downshift lines Ad and Bd, and the throttle opening TA changes so as to cross the upshift lines Au and Bu from the upper side to the lower side. O / D
The cut release control is executed to enter the O / D state. On the contrary, when the throttle opening TA changes so as to cross the downshift lines Ad and Bd from the lower side to the upper side, the O / D cut control is executed and the non-O / D state is set.
The ON line and the OFF line are the same as the ON line and the OFF line shown in FIG.

Further, the downshift line Bd of the map B is set on the higher throttle opening side than the upshift line Au of the map A. This is to prevent hunting from occurring due to map switching.

That is, considering the muffled sound and the acceleration performance in the state where the lockup clutch 7 is engaged, it is desirable that the map B is set to the lower throttle opening side, and the downshift line Bd is the map. It is on the lower throttle opening side than the A upshift line Au.

However, when the map B is set on the low throttle opening side in this way, the accelerator pedal is released during traveling in the O / D cut state to throttle the throttle opening TA.
As a result, if the traveling state crosses the downshift line Ad on the map A and the lock-up state is turned on, the O / D cut control map is switched to the map B, so that the traveling state is the O / D cut on the map B. Enter the area. Therefore, immediately after the throttle opening TA changes so as to cross the upshift line Au of the map A and the upshift occurs, the O /
D-cut control, that is, downshift is executed, and so-called busy shift occurs.

In order to prevent such inconvenience, the downshift line Bd of the map B is set to a higher throttle opening side than the upshift line Au of the map A.
As a result, when the throttle opening TA is decreased, the upshift line Au of the map A is not crossed and the downshift line Bd of the map B is not crossed, so that the downshift immediately after the upshift is prevented.

A control routine for selecting the maps A and B is shown in FIG. First, in step 1, it is determined whether or not the lockup clutch 7 is engaged (ON) (lockup ON). This is specifically determined by a control flag in a predetermined control executed by the automatic transmission electronic control unit 11. If the result of the determination is “No”, the process proceeds to step 2 and the vehicle speed SPD is
It is determined whether or not the lockup clutch 7 exceeds the vehicle speed α in the engaged state. The reference vehicle speed α is, for example, the vehicle speed at which the ON line is set. If the result of the determination is "no", the process proceeds to step 3 and the map A is selected. On the other hand, if the result of the determination in step 1 or step 2 is "no", the process proceeds to step 4 and the map B is selected.

That is, if the lockup clutch 7 is in the released state and the vehicle speed is equal to or lower than the vehicle speed at which the lockup clutch 7 is engaged, the map in which the upshift line and the downshift line are set to the high throttle opening side O / D cut control is performed based on A. When the lockup clutch 7 is in the engaged state, the O / D cut control is performed based on the map B in which the upshift line and the downshift line are set to the lower throttle opening side than the above map A. Be seen. In the range of hysteresis set between the ON line and the OFF line for controlling the lockup clutch 7, the map A and the map B are set.
When the lockup clutch 7 is engaged, the downshift is performed based on the map A and the upshift is performed based on the map B. Therefore, a map or shift line may be appropriately adopted.

Therefore, according to the above-described control, the map in which the O / D cut control is set to a relatively high throttle opening side in the state where the lockup clutch 7 is released and the torque converter 1 performs the torque amplifying action. Since it is performed based on A, the O / D cut, that is, the downshift accompanying the increase of the throttle opening TA is unlikely to occur, in other words, the overdrive state is maintained up to a relatively high throttle opening TA. As a result, the required acceleration force can be obtained by the torque amplifying action of the torque converter 1, and the engine speed can be suppressed to improve the fuel consumption.

When the lockup clutch 7 is engaged, the O / D cut control is performed based on the map B set on the relatively low throttle opening side.
If you depress the accelerator pedal, the
The / D cut control is executed to cause a downshift, and the lockup clutch 7 is released at the same time. Therefore, it is possible to prevent the muffled sound caused by the increase in the throttle opening TA,
In addition, sufficient acceleration can be secured. Further, if the O / D cut is controlled on the basis of this map B, the O / D cut cancellation, that is, the upshift accompanying the decrease of the throttle opening TA, is sufficiently reduced or the vehicle speed is sufficiently increased. Since the vehicle is delayed until a certain amount, the situation in which the vehicle speed cannot be maintained due to the upshift and lockup when the throttle opening TA is reduced after acceleration does not occur.

In the above embodiment, the hydraulic four-speed automatic transmission is described as an example, but the present invention is not limited to the above embodiment, and an electronically controlled automatic transmission is used. It can also be applied to the target shift control device.

[0029]

As described above, according to the present invention,
Since the O / D cut control is performed according to the engagement / disengagement state of the lockup clutch, it is possible to prevent insufficient acceleration due to the delay of the O / D cut and a muffled sound caused by it. It is possible to prevent an increase in the engine speed and an excessive acceleration force due to the O / D cut being too early, and to obtain the optimum acceleration feeling according to the engagement / disengagement state of the lockup clutch as a whole. it can. Further, since the engine is not excessively rotated or the throttle opening is not excessively increased, it is possible to improve fuel efficiency.

[Brief description of drawings]

FIG. 1 is a block diagram schematically showing an embodiment of the present invention.

FIG. 2 is a diagram schematically showing an example of a map for O / D cut control.

FIG. 3 is a flowchart showing an example of a control routine for switching the map.

FIG. 4 is a diagram schematically showing an example of a map for O / D cut control in a conventional control device.

[Explanation of symbols]

 1 Torque Converter 2 3rd Speed Transmission 3 Overdrive 4 Front Cover 6 Turbine Runner 7 Lockup Clutch 11 Electronic Control Unit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Katsunao Takeuchi 9 Kusagi Obayashi, Ahi-cho, Chita-gun, Aichi Prefecture (72) Inventor Toru Sato 117-2 Ikeshita, Hachiman, Chita City, Aichi Prefecture

Claims (1)

[Claims] 1. A lock-up clutch for directly transmitting torque between an input element and an output element in a torque converter, an overdrive section that can be switched between high and low stages, and a map using a value representing a running state as a parameter. A shift control device for an automatic transmission, comprising: an overdrive control means for controlling switching of a lever overdrive portion to a high speed stage or a low speed stage; and lockup detection means for detecting an engaged / released state of the lockup clutch. As the map, a first map having an upshift line and a downshift line set on the higher throttle opening side of the upshift line when the lockup clutch is released is adopted. Is engaged between the upshift line and the downshift line. An automatic vehicle for vehicle, comprising map switching means adopting a second map having a fixed downshift line and an upshift line set to a lower throttle opening side than the upshift line. Gear change control device for transmission.