JPH05180329A - Lock up clutch control device for automatic transmission - Google Patents

Abstract

PURPOSE:To raise engine brake effect when descending a slope and to increase torque when ascending a slope by connecting a lock up clutch when a select is in the engine brake traveling position when the oil temperature is more than the specified value. CONSTITUTION:When the oil temperature detected by an oil sensor is more than the specified value, a lock up clutch 11 makes a connection if the vehicle speed and the throttle open meet the specified requirements. The lock up clutch 11 makes a connection when the second range in the second speed is selected. For example, if the second range is selected in descending a slope, a stronger engine brake effect can be attained because sliding of a torque converter 10 is eliminated. On the other hand, when ascending a slope, D range is suitable. Thus an increased torque action of a torque converter can be gained.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art As a conventional lockup clutch control device for an automatic transmission, there is one disclosed in Japanese Patent Laid-Open Publication No. 57-184752. This is configured to engage the lock-up clutch at the engine brake travel position. This is intended to improve the engine braking effect.

[0003]

However, in the conventional lock-up clutch control device for an automatic transmission as described above, the lock-up clutch is simply engaged at a gear selected in the engine brake range, and a predetermined lock-up clutch is engaged. There is a problem that the engaged state of the lockup clutch cannot be freely selected at the shift speed. For example, when going down a slope, engaging the lockup clutch at the second speed improves the engine braking effect, but when going up a slope, releasing the lockup clutch at the second speed improves the torque of the torque converter. Increased action is obtained and power performance is improved. The conventional lockup clutch control device for an automatic transmission cannot make such a selection.
The present invention aims to solve such problems.

[0004]

The present invention solves the above problems by releasing the lock-up clutch at a predetermined gear in the D range and engaging the lock-up clutch at a predetermined gear in the engine braking range. That is, the lockup clutch control device for an automatic transmission according to the present invention includes a select position detecting means (304) for detecting a select position of a select lever, an oil temperature detecting means (308) for detecting a temperature of hydraulic oil, and a select. When the position is in the normal travel position and the gear is a predetermined gear other than the highest gear and the oil temperature is lower than the predetermined value, the lockup clutch is always released regardless of other conditions such as vehicle speed. When the oil temperature is equal to or higher than a predetermined value, the normal traveling predetermined shift stage lockup clutch control means (steps 106, 108, 110) for permitting engagement of the lockup clutch
And a predetermined gear shift lock-up clutch control means for engine brake travel that permits engagement of the lock-up clutch when the select position is in a position for engine brake travel that prohibits shifting to a speed higher than the predetermined gear. Steps 112 and 114). In addition,
Reference numerals in parentheses indicate corresponding members, steps and the like in the embodiments described later.

When the select position is in the engine brake traveling position where the shift to a speed higher than the predetermined speed is prohibited, the lock-up clutch is allowed to be engaged. Therefore, the lockup clutch is engaged except when the vehicle speed is particularly low. If this select position is selected when going down a slope, slippage of the torque converter is eliminated, and a stronger engine braking effect can be obtained.

On the other hand, when going up a slope, the select position may be set to the normal traveling position (D range). As a result, the lockup clutch is released at the predetermined shift speed, so that the torque increasing action of the torque converter can be obtained and the driving force can be increased. It should be noted that when the vehicle travels continuously on a long slope, the temperature of the hydraulic oil rises, but when the temperature rises above a predetermined value, the lockup clutch is engaged, and a further rise in temperature is prevented.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS.
A description will be given based on 0. FIG. 2 is a skeleton view of a power transmission mechanism of an automatic transmission with four forward speeds and one reverse speed with overdrive. This power transmission mechanism is the torque converter 10
An input shaft 13 to which a rotational force is transmitted from an engine output shaft 12 via an output shaft 14, an output shaft 14 to transmit a driving force to a final drive device, a first planetary gear set 15, and a second planetary gear set 1
6, reverse clutch 18, high clutch 20, forward clutch 22, overrunning clutch 24,
Low and reverse brake 26, band brake 2
8, a low one-way clutch 29, and a forward one-way clutch 30. The torque converter 10 has a lockup clutch 11 built therein.
The first planetary gear set 15 includes a sun gear S1, an internal gear R1, and a carrier PC1 that supports a pinion gear P1 that meshes with both gears S1 and R1, and the planetary gear set 16 includes a sun gear S2. , An internal gear R2, and a carrier PC2 that supports a pinion gear P2 that meshes with both gears S2 and R2 at the same time. The carrier PC1 can be connected to the input shaft 13 via the high clutch 20, and the sun gear S1
Can be connected to the input shaft 13 via a reverse clutch 18. The carrier PC1 can also be connected to the internal gear R2 via the forward clutch 22 and the forward one-way clutch 30 connected in series thereto, or via the over-running clutch 24 arranged in parallel to the forward clutch 22 and the forward one-way clutch 30. Is. The sun gear S2 is always connected to the input shaft 13, and the internal gear R1 and the carrier PC2 are always connected to the output shaft 14. The low and reverse brake 26 can fix the carrier PC1, and the band brake 28 can fix the sun gear S1. The low one-way clutch 29 is arranged in such a direction that the normal rotation (rotation in the same direction as the engine output shaft 12) of the carrier PC 1 is permitted, but the reverse rotation (rotation in the forward rotation and the reverse direction) is not permitted.

The power transmission mechanism includes clutches 18, 2
0, 22 and 24, and brakes 26 and 28 in various combinations to operate the planetary gear sets 15 and 1
6 elements (S1, S2, R1, R2, PC1, and P
The rotation state of C2) can be changed, whereby the rotation speed of the output shaft 14 with respect to the rotation speed of the input shaft 13 can be variously changed. By operating the clutches 18, 20, 22 and 24 and the brakes 26 and 28 in the combination as shown in FIG. 3, the fourth forward speed and the first reverse speed can be obtained. Note that in FIG. 3, the circles indicate operating clutches and brakes, α1 and α2 are the ratios of the number of teeth of the sun gears S1 and S2 to the number of teeth of the internal gears R1 and R2, respectively, and the gear ratio is the output shaft. It is the ratio of the rotation speed of the input shaft 13 to the rotation speed of 14.

4, 5 and 6 show a hydraulic control device for controlling the operation of the power transmission mechanism. This hydraulic control device
Pressure regulator valve 40, pressure modifier valve 42, line pressure solenoid 44, modifier pressure accumulator 46, pilot valve 48, torque converter relief valve 50, lockup control valve 52, first shuttle valve 5
4, lock-up solenoid 56, manual valve 5
8, first shift valve 60, second shift valve 62, first shift solenoid 64, second shift solenoid 66,
Servo charger valve 68, 3-2 timing valve 70, 4-2 relay valve 72, 4-2 sequence valve 74, first reducing valve 76, second shuttle valve 78, overrunning clutch control valve 80, overrunning clutch solenoid. 82, overrunning clutch reducing valve 84, 1-2 accumulator 86, 2-3 accumulator 88, 3-4 accumulator 90, ND
It has an accumulator 92, an accumulator control valve 94, a filter 96, etc., which are connected to each other as shown in the drawing.
1 apply chamber 11a and release chamber 11b are formed), forward clutch 22, high clutch 2
0, band brake 28 (here, a second speed apply chamber 28a, a third speed release chamber 28b, and a fourth speed apply chamber 28c are formed), reverse clutch 1
8, the low and reverse brake 26, and the overrunning clutch 24 are also connected as shown in the drawing, and further, a variable capacity vane type oil pump 34 having a feedback accumulator 32, an oil cooler 3
6, the front lubrication circuit 37, and the rear lubrication circuit 38 are also connected as shown. Detailed description of these valves is omitted. The parts of which description is omitted are the same as those described in JP-A-63-2515621.

The solenoids 44, 56, 64, 66 are shown in FIG.
And control unit 300 for controlling the operation of
Indicates. The control unit 300 includes an input interface 311, a reference pulse generator 312, a CPU (central processing unit) 313, a ROM (read only memory) 3
14, a RAM (random access memory) 315 and an output interface 316, which are connected by an address-by 319 and a data bus 320. The control unit 300 includes an engine speed sensor 301, a vehicle speed sensor 302, a throttle opening sensor 303, a select position switch 304, a kick down switch 305, an idle switch 306, a full throttle switch 307, an oil temperature sensor 308, an input shaft rotation. Signals from the speed sensor 309, the overdrive switch 310, etc. are input. On the other hand, signals are output to the shift solenoids 64 and 66, the overrunning clutch solenoid 82, the lockup solenoid 56, and the line pressure solenoid 44.

In particular, the control of the lockup clutch in the second speed is performed according to the control flow shown in FIG. First, it is determined whether or not it is the second speed (step 102), and if it is the second speed, it is determined whether or not it is the D range (step 104). In the case of the D range, it is determined whether the oil temperature detected by the oil temperature sensor 308 is equal to or higher than a predetermined value (106). When the oil temperature is lower than the predetermined value, the lockup clutch 11
Is released (108). When the oil temperature is equal to or higher than the predetermined value, the lockup clutch 11 is controlled according to the lockup clutch engagement pattern shown in FIG.
0). That is, if the vehicle speed and the throttle opening degree are in predetermined conditions, the lockup clutch 11 is engaged.

If it is not in the D range in step 104, the lockup clutch 11 is controlled according to the lockup clutch engagement pattern shown in FIG.
4).

After all, by the above control, the engagement of the lockup clutch 11 is permitted in the case of the second speed in the second range. Therefore, as shown in FIG. 10, when the vehicle speed is higher than the predetermined value, the lockup clutch 11 is engaged. For example, if two ranges are selected when going down a slope, the torque converter 10 will not slip, and a stronger engine braking effect can be obtained.

On the other hand, when going up a slope, the D range may be set. As a result, the lockup clutch 11 is released in the second speed, so that the torque increasing action of the torque converter 10 can be obtained and the driving force can be increased. It should be noted that the temperature of the hydraulic oil rises when traveling continuously up a long slope, but when the temperature rises above a predetermined value, the lockup clutch 11 is engaged, and a further rise in temperature is prevented.

[0015]

As described above, according to the present invention, the lockup clutch can be engaged or disengaged depending on the selected position even at the same gear. As a result, when going down a slope, the lock-up clutch is engaged to improve the engine braking effect. When going up a slope, the lock-up clutch can be released and a large driving force can be obtained by the torque increasing action of the torque converter.

[Brief description of drawings]

FIG. 1 illustrates the relationship between the components of the present invention.

FIG. 2 shows a framework of an automatic transmission.

FIG. 3 shows a combination of elements that act at each shift speed.

FIG. 4 shows the left half of the hydraulic circuit of the automatic transmission.

FIG. 5 shows the right half of the hydraulic circuit of the automatic transmission.

FIG. 6 shows a positional relationship between FIG. 4 and FIG.

FIG. 7 shows a control unit.

FIG. 8 shows a control flow.

FIG. 9 shows a lockup clutch engagement pattern for the D range.

FIG. 10 shows a lockup clutch engagement pattern for two ranges.

[Explanation of symbols]

304 select position switch (select position detecting means) 308 oil temperature sensor (oil temperature detecting means)

Claims (1)

[Claims] 1. A select position detecting means for detecting a select position of a select lever, an oil temperature detecting means for detecting a temperature of hydraulic oil, a select position at a normal traveling position, and a shift speed other than a maximum shift speed. When the oil temperature is lower than the predetermined value at the specified gear, the lockup clutch is always released regardless of other conditions such as the vehicle speed, but when the oil temperature is higher than the specified value, the lockup clutch is allowed to be engaged. A predetermined gear shift lockup clutch control means and a predetermined engine brake travel permitting engagement of the lockup clutch when the select position is in a position for engine brake travel that prohibits shifting to a speed higher than the predetermined gear. A lockup clutch control device for an automatic transmission, comprising: a shift stage lockup clutch control means.