JP3080083B2 - Lockup control device for automatic transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lock-up state in which a torque converter inserted into a transmission system of an automatic transmission is directly connected between input and output elements. The present invention relates to a lock-up control device for surely completing even when the oil amount balance deteriorates during low engine rotation due to deterioration.

[0002]

2. Description of the Related Art In an automatic transmission, a torque converter is used in order to improve fuel efficiency by improving transmission efficiency, and a torque converter is required in a lock-up region where a torque increasing function and a torque fluctuation absorbing function are unnecessary. In general, a lock-up type is used in which a lock-up state in which input / output elements are directly connected can be obtained.

[0003] Lock-up control of this type of torque converter is conventionally performed by opening the throttle as disclosed in, for example, an automatic transmission described in "NISSAN RE4R01A type full-range electronically controlled automatic transmission maintenance manual" issued by the present applicant. Whether the vehicle is operating in a lockup area with a higher vehicle speed and a lower load than a predetermined lockup line defined on the two-dimensional coordinates of the degree (engine load) and the vehicle speed, or a converter area on the opposite side of the lockup line. In the lockup area, the torque converter is set to a lockup state in which the input and output elements are directly connected, and in the converter area, the torque converter is set to a converter state in which the direct connection is released. It is usual to do.

In order to improve the fuel efficiency by locking up the torque converter, it is necessary to expand the lock-up region so that the torque converter is locked up to a low load operation and a low vehicle speed as much as possible. However, at low vehicle speeds, the engine speed is low, and the torque converter uses oil discharged from the oil pump driven by the engine, including lock-up control, as hydraulic oil. Due to the decrease in the amount of oil, it is difficult to complete the lockup of the torque converter. Therefore, when the lock-up vehicle speed is determined in the initial setting, it is general that the lock-up vehicle speed is set at the very limit in consideration of the limit vehicle speed at which the lock-up of the torque converter can be completed.

However, when the operating oil of an automatic transmission becomes hot or deteriorates, the viscosity of the oil decreases. Therefore, when the operating temperature is high or the deterioration proceeds, leakage of the operating oil from various valves including a lock-up control valve increases. As a result, with the initially set lockup vehicle speed as described above, the torque converter may not be able to be completely locked up due to deterioration of the oil balance in a low vehicle speed region where the engine speed is low.

For this reason, conventionally, for example, Japanese Unexamined Patent Publication No. 7-217
As described in Japanese Unexamined Patent Publication Nos. 733 and 7-217734, when a large slip occurs despite the fact that the torque converter should keep the lock-up state constantly, the lock-up vehicle speed is shifted to a higher vehicle speed side. Shift the engine speed up or increase the engine speed by shifting the lockup vehicle speed to a higher vehicle speed when the time required to complete the lockup exceeds the set value. There has also been proposed a technique that attempts to solve the above problem while avoiding the deterioration of the above.

[0007]

However, in any of the conventional measures, the lock-up vehicle speed is shifted to the high vehicle speed side only when the oil balance deteriorates and the torque converter generates an undesired large slip. (Increasing the engine speed) is implemented, and it is impossible to forbid the torque converter from once generating a large slip, and at this time, the problem of giving a sense of discomfort to the occupant could not be completely eliminated.

Further, when the lock-up vehicle speed is shifted to a higher vehicle speed side as in the prior art, the lock-up line may approach an adjacent shift line, and in this case, the lock-up operation and the shift operation may be complicated. And there is much concern about this. In order to solve this problem, it is conceivable to prohibit lock-up at the corresponding gear in the above-described case. However, simply prohibiting lock-up simply renders the engine speed unnecessary by the prohibition. It has been confirmed that a rise in the noise causes a disadvantage in noise.

According to the first aspect of the present invention, there is provided a method for preventing a hydraulic oil from being deteriorated when a high temperature or deterioration of hydraulic oil occurs before the torque converter generates a large slip. A main object of the present invention is to propose a lock-up control device for an automatic transmission which can avoid a lock-up failure of a torque converter due to the deterioration of the oil balance.

[0010] In addition, in the first invention, when the lockup operation and the shift operation are complicatedly performed due to the above measures, the lockup at the corresponding shift speed is prohibited in order to eliminate the complexity, Another object of the present invention is to provide a lock-up control device for an automatic transmission in which the prohibition does not cause an increase in the engine speed that causes a disadvantage in noise.

A second object of the present invention is to propose a lock-up control device for an automatic transmission which can detect the degree of deterioration of the hydraulic oil simply but relatively accurately.

[0012]

For these purposes, first, the lock-up control device for an automatic transmission according to the first aspect of the present invention is provided with a lock-up control line defined by two-dimensional coordinates of vehicle speed and engine load. In an automatic transmission in which a torque converter in a high vehicle speed range and a low load range is changed from a converter state in which input and output elements are not directly connected to a lockup state in which input and output elements are directly connected, operation of the automatic transmission In accordance with the oil temperature and / or the degree of deterioration of the hydraulic oil, the lock-up line is shifted to a higher vehicle speed side and / or a lower load side at a higher oil temperature and / or a higher degree of deterioration, and the lock-up line is shifted toward the higher vehicle speed side. When the lock-up operation and the gear-shift operation are complicated due to approaching the adjacent shift line at the time of changing the lock-up, the lock-up at the shift speed related to the lock-up line is prohibited and It is characterized in that it has adapted to shift the adjacent shift line to the low vehicle speed side.

A lock-up control device for an automatic transmission according to a second aspect of the present invention is the automatic transmission lock-up control device according to the first aspect,
The present invention is characterized in that the determination is made based on the traveling distance of the vehicle integrated since the hydraulic oil was replaced.

[0014]

According to the present invention, the torque converter is changed from the converter state to the lock-up state in a higher vehicle speed range and a lower load range than the lock-up line. By the way, in the first invention,
According to the hydraulic oil temperature and / or hydraulic oil deterioration degree of the automatic transmission, the lock-up line is shifted toward a higher vehicle speed side and / or a lower load side at a higher oil temperature and / or a higher deterioration degree,
Lockup is started under high engine speed.

For this reason, the lockup of the torque converter is not performed under a low engine speed range in which the lockup is incomplete due to deterioration of the oil balance when the hydraulic oil is at a high temperature or at high deterioration. In addition, it is possible to prevent the lock-up of the torque converter from becoming incomplete at the time of the high oil temperature or the high deterioration. Moreover, according to the first aspect of the invention, the above measures are not taken after the torque converter generates a large slip due to imperfect lock-up, but the oil amount balance generated when the operating oil is at a high temperature or deteriorates before the slip occurs. Therefore, it is possible to avoid a lock-up failure of the torque converter due to the deterioration of the oil balance without the above-mentioned uncomfortable feeling due to the occurrence of slip.

Further, in the first invention, when the lock-up line approaches a shift line adjacent to the lock-up line when the lock-up line is changed to a high vehicle speed side, the lock-up operation and the shift operation are performed in a complicated manner. Since lock-up at the shift speed related to the up-line is prohibited and the adjacent shift line is shifted to the low vehicle speed side, the following operational effects can be obtained. That is, first, the lock-up is prohibited, so that lock-up at the corresponding shift speed is not performed, so that it is possible to prevent the lock-up operation and the shift operation related to the adjacent shift line from occurring frequently.

Further, by prohibiting the lock-up,
Since the adjacent shift line is shifted to the low vehicle speed side, the automatic transmission tends to up-shift and the increase in the engine speed can be suppressed. There is no increase in engine speed.

In the second invention, the degree of deterioration of the hydraulic oil is determined simply, but relatively accurately, by judging the degree of deterioration of the hydraulic oil from the traveling distance of the vehicle integrated from the time of replacement of the hydraulic oil. This is a great advantage in implementing the first invention.

[0019]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a lock-up control device for an automatic transmission according to an embodiment of the present invention. In this figure, 1 is an engine, and 2 is an automatic transmission. The automatic transmission 2 receives the power of the engine 1 via the torque converter 3, changes the input rotation at a gear ratio according to the selected shift speed, and transmits the input rotation to the output shaft 4.

Here, the automatic transmission 2 turns on and off the shift solenoids 6 and 7 in the control valve 5.
And the torque converter 3 is controlled by the duty control of the lock-up solenoid 8 in the control valve 5 so that the input / output elements are not directly connected to each other, or the input / output elements are directly connected to each other. Shall be

ON / OFF of shift solenoids 6, 7;
And the drive duty D of the lock-up solenoid 8
Are controlled by a controller 9. The controller 9 receives a signal from a throttle opening sensor 10 for detecting a throttle opening TVO of the engine 1 and a vehicle speed VS.
A signal from a vehicle speed sensor 11 for detecting P, a signal from a traveling distance counter 12 for detecting a vehicle traveling distance L (representing a degree of deterioration of hydraulic oil) after the transmission hydraulic oil is replaced, and a transmission hydraulic oil temperature TMP. Are respectively input from the oil temperature sensors 13 for detecting the pressure.

Although not shown, the controller 9 performs the following shift control and normal lock-up control by well-known calculations based on these input information. First, the shift control will be described. The controller 9 includes a throttle opening TVO detected by the sensor 10 and a vehicle speed V detected by the sensor 11.
From the SP, the optimum gear position for the current operating state is obtained by a look-up method from table data corresponding to, for example, the shift lines indicated by the solid line and the broken line in FIG. 4, and the shift solenoid 6 is selected so that the optimum gear position is selected. , 7 ON, O
FF is performed to perform a predetermined shift.

Next, the normal lock-up control will be described.
Is obtained from a table data corresponding to a lock-up line (L / U is a lock-up area) indicated by a one-dot chain line and a two-dot difference line in FIG. 4, based on the throttle opening TVO and the vehicle speed VSP by a look-up method. The torque converter 3 is locked or brought into the converter state through the duty control of the lock-up solenoid 8 according to the result of the determination. The lock-up of the torque converter 3 is achieved by setting the drive duty D of the solenoid 8 to, for example, 95%, and the converter state of the torque converter 3 is achieved by setting the drive duty D of the solenoid 8 to, for example, 5%. It shall be.

The controller 9 further executes the control program shown in FIG. 2 to change the lock-up line and the shift line targeted by the present invention. The control program of FIG. 2 is repeatedly executed by a periodic interruption. First, in steps 21 and 22, the selected gear position and the selected range are related to the change of the lock-up line and the shift line, respectively. In other words, it is checked whether the third speed or the fourth speed is being selected and whether the automatic shift (D) range is being selected. Since the present invention is not involved in the present invention based on the shift speed and the selected range that are not related to the change of the lock-up line and the shift line, the control is terminated.

When it is determined in steps 21 and 22 that the third speed or the fourth speed is selected in the D range,
In step 23, the vehicle travel distance L after hydraulic oil replacement measured by the counter 12 and the transmission hydraulic oil temperature TMP detected by the sensor 13 are read. Then step 24
, The degree of change of the fourth speed lockup line from the travel distance L and the hydraulic oil temperature TMP based on the map illustrated in FIG.
Search for ~ III. The degree of change 0 is a degree at which the fourth-speed lock-up line shown by a one-dot chain line in FIG.
Indicates that the four-speed lock-up line is greatly changed from the normal one shown in FIG.

At the time of this change, in the next step 25, the four-speed lock-up line shown by the one-dot chain line in FIG. 4 is changed to the high vehicle speed side, the low throttle opening degree side, or both of them according to the above change degrees 0 to III. And the changed 4-speed lock-up line contributes to lock-up control. Here, the change of the 4-speed lockup line is performed by changing
As is clear from the speed lockup line change degree map,
The longer the traveling distance L and the higher the hydraulic oil temperature TMP, the larger the distance. As a result, if the traveling distance L becomes longer or the hydraulic oil temperature TMP becomes higher, the lockup region becomes narrower and the vehicle speed becomes higher. If the throttle opening is not further reduced, that is, if the engine speed is not further increased, lock-up is not performed.
Accordingly, the fourth speed lock-up is not performed when the oil balance is deteriorated in the low engine rotation range due to the long running distance L or the increase in the hydraulic oil temperature TMP, and the lock-up due to the deterioration of the oil balance is prevented. Incompleteness can be prevented.

When the third-speed lock-up line shown by the two-dot chain line in FIG. 4 is changed in the same manner as the fourth-speed lock-up line, the adjacent third-to-fourth shift line is approached and the lock-up operation and the shift operation are performed. Is accompanied by a sense of incongruity, which occurs frequently. However, if lock-up control is performed based on the usual three-speed lock-up line, lock-up becomes incomplete under a low engine speed range when the hydraulic oil deteriorates or becomes hot. Cause problems.

Therefore, in this embodiment, in step 26, whether the hydraulic oil temperature TMP or the traveling distance L is equal to or greater than the set values TMP _S and L _S illustrated in FIG. It is determined whether or not the state of the hydraulic oil causing the incomplete lockup is present. If lock-up is incomplete, step 27 inhibits third-speed lock-up, thereby eliminating the problem associated with incomplete lock-up.

The prohibition of the lock-up of the third speed causes an increase in the engine speed at which a gear ratio such as the third speed is accompanied by a disadvantage in terms of noise, thereby lowering the commercial value of the vehicle equipped with the automatic transmission. Let me do it. Therefore, in the present embodiment, when prohibiting the third-speed lockup in step 27,
In step 28, the 3 → 4 shift line adjacent to the 3rd speed lockup line is changed from the normal one shown in FIG. 4 to the low vehicle speed side to contribute to the 3 → 4 shift control.

The change of the 3 → 4 shift line makes it easy to select the 4th speed by increasing the 4th speed selection area and reducing the 3rd speed selection area, and consequently the engine speed due to the prohibition of the 3rd speed lockup. Can be suppressed by the tendency to select the 4th speed, and the prohibition of the lockup of the 3rd speed can avoid an increase in the engine speed which is accompanied by a disadvantage in terms of noise.

[0031] In step 26, if it is determined that the working oil temperature TMP, and the travel distance L is less than the set value TMP _S and L _S, of the hydraulic fluid even under a low engine speed region results in defective of the lock-up Since it is not in the state, the steps 27 and 28 are skipped, so that the normal third-speed lockup and the 3 → 4 shift based on the shift diagram of FIG. 4 are performed.

In the above-described embodiment, the higher the oil temperature and / or the higher the degree of deterioration, the greater the oil temperature TMP of the automatic transmission and / or the vehicle travel distance L (deterioration of operating oil) after replacing the operating oil. Move the 4-speed lockup line to the higher speed side and / or
Alternatively, shifting to the low throttle opening side (low load side) starts the 4-speed lockup under a high engine speed, so the oil balance deteriorates when the operating oil temperature is high or when it is highly degraded. The lockup of the torque converter will not be performed under the low engine speed range where the lockup is incomplete, and the lockup of the torque converter will be incomplete at the time of high oil temperature or high deterioration. Can be prevented.

Further, in the present embodiment, the above-described countermeasures are not taken after the torque converter generates a large slip due to imperfect lock-up, but the oil generated at the time of high temperature or deterioration of the hydraulic oil before the slip occurs. Since the deterioration of the oil balance is predicted and taken as a countermeasure, it is advantageous that a lock-up failure of the torque converter due to the deterioration of the oil balance can be avoided without a sense of incongruity due to occurrence of slip.

In the case where the lock-up line approaches the adjacent shift line when the lock-up line is changed and the lock-up operation and the shift operation are performed in a complicated manner, the lock-up at the shift speed related to the lock-up line is performed. (3rd-speed lockup in the present embodiment) is prohibited, and the adjacent shift line (3 → 4 shift line in the present embodiment).
Is shifted to the low vehicle speed side, the following operational effects can be obtained. That is, first, lock-up (third-speed lock-up) is not performed at the corresponding gear by prohibiting the lock-up, and this lock-up operation and the adjacent shift line (3
The shift operation related to (→ 4 shift line) can be prevented from occurring in a complicated manner. Further, even if the lock-up is prohibited, the adjacent shift line is shifted to the lower vehicle speed side, so that the automatic transmission tends to up-shift, and the increase in the engine speed can be suppressed. There is no increase in engine speed which would cause a noise penalty.

In the present embodiment, as described above, the degree of deterioration of the hydraulic oil is determined based on the traveling distance L of the vehicle integrated from the time of replacement of the hydraulic oil. It is very advantageous to be able to detect relatively accurately.

[Brief description of the drawings]

FIG. 1 is a system diagram showing a control system of an automatic transmission including a lock-up control device according to an embodiment of the present invention.

FIG. 2 is a flowchart showing lock-up line change control and shift line change control to be performed by the controller at the time of high operating oil temperature and at the time of hydraulic oil deterioration.

FIG. 3 is a map diagram of a fourth-speed lockup line change degree used in the example.

FIG. 4 is a shift pattern diagram of the automatic transmission in which a lock-up line of the torque converter is shown.

[Explanation of symbols]

 Reference Signs List 1 engine 2 automatic transmission 3 torque converter 5 control valve 6 shift solenoid 7 shift solenoid 8 lock-up solenoid 9 controller 10 throttle opening sensor 11 vehicle speed sensor 12 mileage counter 13 oil temperature sensor

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-7-229558 (JP, A) JP-A-4-3477051 (JP, A) JP-A-4-277370 (JP, A) JP-A 8- 233092 (JP, A) JP-A-7-217734 (JP, A) JP-A-7-217733 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F16H 61/14 F16H 59 / 00-61/12 F16H 61/16-61/24 F16H 63/40-63/48

Claims (2)

(57) [Claims] 1. A torque converter in a higher vehicle speed range and a lower load range than a predetermined lock-up line defined on two-dimensional coordinates of vehicle speed and engine load. An automatic transmission in which a lock-up state in which elements are directly connected to each other, wherein the higher the oil temperature and / or the higher the degree of deterioration of the automatic transmission, the more the lock becomes. If the lock-up line is shifted toward the high vehicle speed side and the lock-up line approaches an adjacent shift line and the lock-up operation and the shift operation are performed in a complicated manner, the shift-up line is shifted to the high vehicle speed side and / or the low load side. Lock-up of an automatic transmission, wherein lock-up at a gear associated with the lock-up line is prohibited, and the adjacent shift line is shifted to a lower vehicle speed side. The control device. 2. The lock-up control device for an automatic transmission according to claim 1, wherein the degree of deterioration of the hydraulic oil is determined based on a traveling distance of the vehicle integrated from the time of replacement of the hydraulic oil.