JPH08210491A - Control device of automatic transmission for vehicle - Google Patents

Abstract

PURPOSE: To prevent the generation of a speed change shock by controlling engaging/disengaging a lock up clutch based on a map of a speed change shift before a speed change in a period till starting the speed change, in controlling engaging/disengaging the lock up clutch in accordance with an engine load and a car speed. CONSTITUTION: When output a speed change command by manual operation, by an electronic control unit Ut, an oil pressure of a hydraulic engaging element in a preceding stage in an automatic transmission T is decreased, to increase an oil pressure of a hydraulic engaging element in a following stage. In the case of exceeding a prescribed value in a slip factor of the hydraulic engaging element calculated based on outputs of a main shaft rotational speed sensor S3 and a counter shaft rotational speed sensor S4 , starting a speed change is judged. In this condition, next when a following stage transmission is, for instance, in a 4-speed change shift, a 4-speed lock up map is selected to control a lock up clutch L, so as to avoid blowing up an engine speed in the case of transferring this clutch L to a disengaging condition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a vehicle automatic transmission having a lockup clutch.

[0002]

2. Description of the Related Art Conventionally, an optimum shift speed is selected by searching a shift map using detected values such as vehicle speed and engine load as parameters, and automatic shift operation is performed so that the shift speed is established. Transmissions are known. Generally, automatic transmissions are equipped with a fluid torque converter between the engine, which is the power source, and the speed change mechanism, utilize the torque increase characteristics during acceleration such as starting or overtaking, and input and output during cruise. A lock-up clutch that directly connects or semi-engages and is engaged to prevent a decrease in efficiency due to fluid transmission.

In such an automatic transmission, when the gear shift is performed while the lock-up clutch is engaged and it is inappropriate that the lock-up clutch is engaged at the gear stage established by the gear shift, the lock-up clutch is engaged. It is known that a gear shift is commanded after the engagement is released (see Japanese Patent Publication No. 63-18053).

[0004]

However, since there is a time lag from when the gear shift is commanded until the gear shift is actually started, if the lockup clutch is disengaged and the gear shift is commanded as described above. In particular, when the accelerator pedal is depressed, the engine speed increases due to a decrease in the load accompanying the disengagement of the lockup clutch, and if gear shifting is performed in this state, a shift shock may occur.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to appropriately control the lock-up clutch to prevent the engine speed from rising and a shift shock to occur during a shift. .

[0006]

In order to achieve the above object, the invention described in claim 1 is a torque in which an input side is connected to an engine and an output side is connected to a gear transmission mechanism having a plurality of gear stages. A converter and a lockup clutch connecting the input side and the output side of the torque converter,
A control device for an automatic transmission for a vehicle, comprising: a control means for controlling engagement and disengagement of a lock-up clutch in accordance with an engine load and a vehicle speed based on a map set for each shift speed. The means controls engagement and disengagement of the lock-up clutch based on a map of the shift speed before the shift until a substantial shift is started from the shift determination or shift command.

According to the invention described in claim 2, in addition to the structure of claim 1, substantial shift is started,
It is characterized in that the determination is made by the slippage of the hydraulic engagement element that establishes the shift speed before the shift.

According to the invention described in claim 3, in addition to the structure of claim 1, the period from the determination of the shift or the shift command to the start of the substantial shift is set to at least one of the engine load and the vehicle speed. It is characterized in that the determination is made by a timer set based on the above.

[0009]

According to the first aspect of the present invention, even if there is a gear shift determination or gear shift command during the engagement of the lockup clutch, the lockup clutch is not immediately disengaged, and after the substantial gear shift is started. Since the lock-up clutch is disengaged, the engine speed is prevented from rising in the period from the shift determination or shift command to the substantial shift start,
Shift shock can be reduced.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

1 to 8 show an embodiment of the present invention. FIG. 1 is an overall structural view of an automatic transmission for a vehicle and its control device, and FIG. 2 shows a selector lever shared with a manual shift lever. 5 is a perspective view of a manual shift lever provided on the steering column, FIG. 4 is a view showing indicators of a select position and a shift stage, and FIG.
7 is a diagram showing another alternative of the indicator for the select position and the shift stage, FIG. 6 is a flowchart for explaining the action, FIG.
Is a lockup map in the “M” range, and FIG. 8 is a time chart for explaining the operation.

FIG. 1 shows a 7-position automatic transmission T for a vehicle.
7 types of ranges depending on the select lever, that is, “P” range (parking range), “R” range (reverse range), “N” range (neutral range), “D” range (1st speed to 4th speed). Speed automatic shift range), "M" range (1st to 4th speed manual shift range),
"2" range (including 2nd fixed range, 3rd gear shift → 2nd gear shift down) and "1" range (1st fixed range, 2nd gear shift → 1st hold gear shift down) It is possible to select any of (including).

The automatic transmission T has a main shaft MS connected to a crankshaft 1 of an engine E via a torque converter 2 having a lockup clutch L, a countershaft CS arranged parallel to the main shaft MS, And a secondary shaft SS.

The main shaft MS supports a main first speed gear 3, a main second speed-third speed gear 4, a main fourth speed gear 5, and a main reverse gear 6. Counter shaft C
S is a counter first speed gear 7 that meshes with the main first speed gear 3 and a counter second speed-that meshes with the main second speed-third speed gear-4.
Counter fourth speed gear 9, counter second speed gear 10, main reverse gear 6 meshing with third speed gear 8 and main fourth speed gear 5.
A counter reverse gear 12 connected to the reverse idle gear 11 is supported. The secondary shaft SS supports a first secondary second speed gear 13 that meshes with the counter second speed-third speed gear 8 and a second secondary second speed gear 14 that meshes with the counter second speed gear 10.

When the main first speed gear 3 rotatably supported on the main shaft MS is connected to the main shaft MS by the first speed clutch C ₁ , the first speed gear stage is established. Since the first speed clutch C ₁ is maintained in the engaged state even when the second speed to the fourth speed is established, the counter first speed gear 7 is supported via the one-way clutch C _OW . The second secondary second speed gear 14 which is rotatably supported on the secondary shaft SS is
When the secondary clutch SS is engaged with the high speed clutch C ₂ , the second speed is established. When the counter second-speed -3-speed gear 8, relatively rotatably carried on the counter shaft CS by the third speed clutch C ₃ counter coupled to the shaft CS, 3
The high speed stage is established.

In a state where the counter fourth speed gear 9 rotatably supported on the counter shaft CS is coupled to the counter shaft CS by the selector gear SG, the main shaft MS is
When the main fourth speed gear 5 rotatably supported in the main shaft MS is connected to the main shaft MS by the fourth speed-reverse clutch C _4R , the fourth speed gear is established. With the counter reverse gear 12 rotatably supported on the counter shaft CS coupled to the counter shaft CS by the selector gear SG, the main reverse gear 6 rotatably supported on the main shaft MS is connected by the fourth speed-reverse clutch C _4R . When connected to the main shaft MS, a reverse gear is established.

The rotation of the counter shaft CS is transmitted to the differential D via the final drive gear 15 and the final driven gear 16, and from there to the drive wheels W, W via the left and right axles 17, 17.

When the first speed hold clutch C _LH is used to _connect the counter first speed gear 7 to the counter shaft CS while the first speed clutch C ₁ is engaged, the first speed hold gear is established. If the first speed hold gear is established when engine braking is required, the torque of the drive wheels W, W can be transmitted to the engine E in reverse even if the one-way clutch C _OW slips.

The electronic control unit Ut for controlling the automatic transmission T comprises a CPU 18, a ROM 19, a RAM 20, an input circuit 21 and an output circuit 22.

The throttle opening TH detected by the throttle opening sensor S ₁ provided on the engine E, the engine rotation speed Ne detected by the engine rotation speed sensor S ₂ provided on the engine E, and the main shaft MS provided on the main shaft MS. Main shaft speed Nm detected by shaft speed sensor S ₃
And the counter shaft rotation speed Nc detected by the counter shaft rotation speed sensor S ₄ provided on the counter shaft CS.
And the vehicle speed V detected by the vehicle speed sensor S ₅ provided on the differential D, and the select lever position sensor S ₆
A select lever position P detected in a shift-up switch S ₇ which will be described later, the shift down switch S ₈ which will be described later, the cooling water temperature Tw detected by the water temperature sensor S ₉ provided in the engine E, the electronic control unit Ut It is input to the input circuit 21.

The output circuit 22 of the electronic control unit Ut is
1st speed clutch C ₁ of automatic transmission T, 2nd speed clutch C ₂ ,
Five solenoids SL ₁ to 5 provided in the hydraulic control circuit O for controlling the operations of the third speed clutch C ₃ , the fourth speed-reverse clutch C _4R , the first speed hold clutch C _LH , the selector gear SG and the lockup clutch L. Connected to SL ₅ . Solenoid SL ₁ turns on lockup clutch L
ON / OFF, the solenoid SL ₂ controls the capacity of the lockup clutch L, and the solenoids S ₃ and S ₄ are 1
ON / OFF of the high speed clutch C ₁ , the second speed clutch C ₂ , the third speed clutch C ₃ , the fourth speed-reverse clutch C _4R and the first speed hold clutch C _LH , and the operation of the selector gear SG, and the solenoid SL ₅ is the clutch hydraulic pressure. Control the.

As shown in FIG. 2, the range selected by the select lever 25 is the normal "P" range or "R" range.
In addition to the range, the “N” range, the “D” range, the “2” range, and the “1” range, the “M” range (1st to 4th speed manual shift range) is provided. The guide groove 26 that guides the select lever 25 is formed in a substantially H shape, and the position where the select lever 25 is tilted to the right from the “D” range is the “M” range, where the select lever 25 can be tilted back and forth. Is. When the select lever 25 is tilted forward (+ direction) in the "M" range, the shift up switch S ₇
Is operated to output a shift-up command, and when the select lever 25 is tilted backward (-direction), the shift-down switch S ₈ is operated to output a shift-down command.

In FIG. 3, a manual shift lever 27 is provided separately from the select lever 25, and the steering column 2 supporting a steering wheel 28 is provided.
Manual shift lever 2 that can be swung up and down on the left side of 9
7 is provided. Select lever 25 (not shown) is "D"
The "M" range is provided between the range and the "2" range, and when the manual shift lever 27 is tilted upward (+ direction) while the "M" range is selected by the select lever 25, the shift up switch S ₇ operates to output a shift-up command, and when the manual shift lever 27 is tilted downward (-direction), the shift-down switch S ₈
Is activated and a downshift command is output.

As shown in FIG. 4, an indicator 33 provided on a meter panel 32 having a speedometer 30 and a tachometer 31 displays the range selected by the select lever 25 and also selects the "M" range. When it is being operated, the currently established gear stage is displayed. Alternatively, as shown in FIG. 5, the tachometer 31
The range selected by the select lever 25 is displayed on the indicator 33 provided in the above, and when the "M" range is selected, the currently established shift speed is displayed.

In FIGS. 4 and 5, the visibility is further improved by blinking the display of the currently established shift speed. Further, instead of displaying the 1st to 4th gears with the numbers 1 to 4, it is possible to display the gear ratio of the gears.

Then, "D" is selected by the select lever 25.
When the range is selected, based on the shift map having the vehicle speed V detected by the vehicle speed sensor S ₅ and the throttle opening TH detected by the throttle opening sensor S ₁ as parameters, the 1st speed shift stage to the 4th speed shift stage Up-shifting and down-shifting in between are automatically performed. Further, when the "2" range is selected, the second speed shift stage is established. However, if the vehicle speed is too high when the "2" range is selected and an overrev occurs at the second speed shift stage, first, the third speed shift speed is set. Dan is established,
After the vehicle speed decreases, downshifting to the 2nd speed
It is fixed to the high speed stage. Similarly, when the vehicle speed is high when the "1" range is selected and an overrev occurs at the 1st hold gear, the 2nd gear is first established.
After the vehicle speed has decreased, the vehicle is downshifted to the first speed hold gear and fixed to the first speed hold gear.

When the "D" range is switched to the "M" range, the gear position in the "D" range before the switching is 1
If the shift speed is from the third shift speed to the third shift speed, the same shift speed is held in the "M" range after switching. If the shift speed in the “D” range before switching is the fourth shift speed, the third shift speed is established in the “M” range after switching. However, if overrev occurs when the third speed is established, the fourth speed is exceptionally established.

When the "2" range is switched to the "M" range, the gear stage in the "2" range before the switching is three.
Regardless of whether it is the first gear or the second gear, the third gear is established in the "M" range after the switching. However,
When the "2" range is switched to the "M" range when the vehicle is stopped, the first speed gear stage is established in the "M" range after the switching.

Further, by operating the shift-up switch S ₇ or the shift-down switch S ₈ while the vehicle is stopped in the "M" range, the first speed or the second speed is set as the speed when starting the vehicle.
A high speed gear can be selected.

FIG. 7 is a lockup map set in the "M" range. In the area A, the lockup clutch L is engaged only at the second speed shift stage, and in the area B, the second speed shift stage and the third speed shift are performed. In the C range, and in the C range, the second gear
Engages in the third and fourth gears. Therefore, for example, although the lockup clutch L is engaged when the second speed is established at point (a) in the area A,
At point (a), when the second gear is shifted up to the third gear, the lockup clutch L is disengaged. In this lockup map, hysteresis is set between the engagement → disengagement of the lockup clutch L and the disengagement → engagement.

Next, the control of the lockup clutch L of the torque converter 2 at the time of shifting in the "M" range will be described with reference to the flowchart of FIG.

First, when a manual shift command is output (step S1), in order to establish a new shift stage, the hydraulic pressure of the hydraulic engaging element in the preceding stage begins to decrease and the hydraulic pressure of the hydraulic engaging element in the subsequent stage starts to decrease. Begins to increase. At this time, the main shaft rotational speed Nm detected by the main shaft rotational speed sensor S _3, the slip rate ECL of the hydraulic engaging element is calculated based on the counter shaft rotation speed Nc detected by the counter shaft revolution speed sensor S ₄ If the value exceeds the predetermined value, it is determined that the hydraulic engagement element of the preceding stage starts to slide and the actual shift is started (step S2).

If the rear gear is the fourth gear, the lockup map for the fourth gear is used. If the rear gear is the third gear, the lockup map for the third gear is used. If it is the second speed, the lockup map for the second speed is selected (steps S3 to S7), and the operation of the lockup clutch L is controlled based on the lockup map.

As described above, after the shift command is output,
By operating the lock-up clutch L after the substantial shift is started, the engine speed is prevented from rising when the lock-up clutch L shifts from the engaged state to the disengaged state due to the shift. can do. This will be further described with reference to FIG.

FIG. 8 is a time chart in the case of shifting up from the 2nd gear to the 3rd gear at point (a) of FIG. 7 and shows the lockup clutch L at the 2nd gear.
Is in the engaged state and is in the disengaged state at the third speed.
When the shift-up command is output at time t ₁ , the hydraulic pressure of the former hydraulic engaging element (second speed clutch C ₂ ) begins to decrease and the hydraulic pressure of the latter hydraulic engaging element (3rd clutch C ₃ ) increases. By starting the operation, first, the hydraulic engagement element at the front stage is disengaged and the main shaft MS and the counter shaft CS are disconnected, and then the hydraulic engagement element at the rear stage is engaged and the main shaft MS and the counter shaft CS are eventually engaged. And are connected.

At this time, at time t ₁ as shown in the figure.
In other have the upshift when a command is output at the same time 2 speed lockup map of the third speed lockup map of the lock-up clutch at time t ₁ L
Is disengaged and the load on the engine E decreases,
Moreover, since there is a time lag before the actual shift is started at time t ₂ , the engine speed rises as shown in (A) and shift shock (change in output shaft torque) is large. Become.

On the other hand, according to the present invention, by monitoring the slip ratio ECL of the hydraulic engagement element, when the slip ratio ECL increases at time t ₂ , that is, slippage occurs in the preceding hydraulic engagement element. When it is determined that the substantial shift has started, the lockup map for the second speed is switched to the lockup map for the third speed. As a result, the lock-up clutch L is disengaged at the time t ₂ instead of the time t ₁ , but the subsequent third speed is established in a short time thereafter, so that the engine speed is prevented from rising. The shift shock associated therewith is reduced.

Although the embodiments of the present invention have been described in detail above, the present invention can be modified in various ways without departing from the scope of the invention.

For example, the engagement of the lock-up clutch L is not limited to the direct connection state without slip, and includes the slip engagement state. Further, in the embodiment, it is determined that the substantial gear shift is started based on the slip ratio ECL of the hydraulic engagement element. However, this is measured by a timer with the elapsed time from when the gear shift command is output. It can be determined that the substantial gear shift has started when the predetermined time has elapsed. In this case, the higher the vehicle speed and the higher the throttle opening, the more time it takes to start the gear shift. Therefore, the count time of the timer is set to be long. Further, in the embodiment, the lockup map of the shift stage before the shift is used during the period from the shift command to the substantial start of the shift, but instead of using the shift command as a reference, the electronic control unit Ut performs the shift. It is possible to use the gear shift judgment as a reference.

[0040]

As described above, according to the first aspect of the present invention, the lockup clutch is engaged and disengaged during the period from the shift determination or the shift command until the shift is substantially started. Is controlled based on the map of the gear position before shifting, so even if there is a shift determination or shift command while the lockup clutch is engaged, the lockup clutch is not immediately disengaged and a substantial shift is started. After that, the lockup clutch is disengaged, so that the engine is prevented from rising and the shift shock is reduced.

According to the invention described in claims 2 and 3, it is possible to reliably detect that the substantial gear shift has started.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a vehicle automatic transmission and its control device.

FIG. 2 is a perspective view of a select lever shared with a manual shift lever.

FIG. 3 is a perspective view of a manual shift lever provided on a steering column.

FIG. 4 is a view showing indicators for a select position and a shift stage.

FIG. 5 is a view showing another alternative of the indicator for the select position and the gear position.

FIG. 6 is a flowchart illustrating the operation.

FIG. 7: Lockup map in the “M” range

FIG. 8 is a time chart explaining the operation.

[Explanation of symbols]

 E engine L lockup clutch T automatic transmission Ut electronic control unit (control means) 2 torque converter

Claims (3)

[Claims] 1. A torque converter having an input side connected to an engine and an output side connected to a gear speed change mechanism having a plurality of speed stages, a lockup clutch connecting the input side and the output side of the torque converter, and each speed stage. A control means for controlling engagement and disengagement of the lock-up clutch according to an engine load and a vehicle speed based on a map set for each, and a control device for an automatic transmission for a vehicle, wherein the control means is A vehicle automatic control characterized by controlling engagement and disengagement of the lock-up clutch based on a map of a shift stage before shifting, from a shift determination or a shift command until a substantial shift is started. Transmission control device. 2. The automatic transmission for a vehicle according to claim 1, wherein it is determined that the substantial gear shift has started by a slip of a hydraulic engagement element that establishes a gear stage before the gear shift. Control device. 3. A timer set based on at least one of an engine load and a vehicle speed is used to determine a period from a shift determination or a shift command until a substantial shift is started. A control device for an automatic transmission for a vehicle as described.