JP3274205B2 - 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 control device for an automatic transmission, and more particularly, to a control device for an automatic transmission for controlling the oil temperature of the automatic transmission.

[0002]

2. Description of the Related Art Generally, an automatic transmission is provided with an oil temperature sensor, and when the oil temperature exceeds an allowable temperature,
Lock-up and shift-down are performed to prevent the oil temperature from rising. For example, Japanese Patent Application Laid-Open No. 4-663
In the device described in Japanese Patent Publication No. 37, when the oil temperature of the transmission becomes high, by increasing the engine speed,
The required discharge amount of the oil pump is secured even at a high oil temperature, and the minimum required oil pressure is maintained during idling .

It is desirable to detect both the oil temperature in the torque converter and the oil temperature of the automatic transmission main body. Detecting the oil temperature in the torque converter
For example, when the oil temperature in the torque converter rises, the viscosity of the oil decreases, so it is necessary to take necessary measures such as lock-up.To detect the oil temperature of the automatic transmission main body, for example, This is because duty control may be performed depending on the oil temperature of the automatic transmission body.

[0004] In order to detect both oil temperatures, it is most desirable to provide two oil temperature sensors. However, since the torque converter is constantly rotating, the torque converter is not suitable as a position where the oil temperature sensor is provided. Therefore, generally, as shown in FIG. 1, only one oil temperature sensor 6 is attached to only one of the valve bodies in the oil pan 4 adjacent to the torque converter 2.

[0005] The oil temperature sensor first detects the oil temperature in the oil pan (that is, the oil temperature in the main body of the automatic transmission). At the same shift speed, there is a relationship that the oil temperature of the oil pan and the oil temperature in the torque converter maintain a constant difference, so if a predetermined value is added to the detected oil temperature of the oil pan, the torque The oil temperature of the converter can be determined.

Conventionally, the oil temperature of both the automatic transmission main body and the torque converter is detected by one oil temperature sensor in this manner, and control is performed so that the oil temperature in each does not exceed the allowable temperature. Was. FIG. 2 is a schematic diagram showing the configuration of a conventional control device for an automatic transmission. The operation of the automatic transmission 10 is controlled by the automatic transmission controller 12. When the oil temperature sensor 14 attached to the lower part of the oil pan sends a signal X1 representing the oil temperature to the controller 12, the controller 1
2 calculates the oil temperature of the torque converter by adding a predetermined value (for example, 15 degrees) to the oil temperature of the oil pan represented by the signal X1 and the oil temperature of the oil pan. Controller 12
Executes the necessary control for lowering the oil temperature when the calculated oil temperatures exceed the set value A (allowable temperature).
For example, when the calculated oil temperature of the torque converter exceeds the set value A, a signal X2 is transmitted to the automatic transmission 10,
Lock-up or down-shift is executed, thereby reducing the oil temperature. The setting of the gear position in the automatic transmission 10 itself has been performed by the gear position setting means 16 of the controller 12 completely independently of the above oil temperature control.

Conventionally, the set value A has been set as follows. In a vehicle equipped with an engine having a relatively small torque, a predetermined shift speed, for example, D
The third speed range (drive range) was used. The temperature difference between the allowable temperature of the oil pan and the allowable temperature of the torque converter in the third range of the D range is determined in advance and is about 15 degrees. For example, as shown in FIG. 3, when the oil temperature of the oil pan reaches its allowable temperature of 135 degrees, the oil temperature of the torque converter becomes the allowable temperature of 15 degrees.
Reaches 0 degrees.

On the other hand, in the same vehicle, if only the engine is changed to an engine having a relatively large torque without changing the automatic transmission, not only the third speed in the D range,
It may be possible to go uphill even at 4th speed in the D range. This D
The temperature difference between the allowable temperature of the oil pan and the allowable temperature of the torque converter at the fourth speed of the range can be determined in advance, and is about 20 degrees. For this reason, the temperature difference between the oil pan and the torque converter is reduced by 15
When the oil temperature of the oil pan reaches the allowable temperature of 135 degrees, the oil temperature of the torque converter reaches 155 degrees, as shown in FIG. 5 degrees may be exceeded, which is the allowable temperature of 150 degrees.

In a conventional automatic transmission, as a countermeasure against this,
The set value A for the oil pan is the original allowable temperature of 1
The angle was set to 130 degrees, which is 5 degrees lower than 35 degrees. In this way, as shown in FIG. 5, when the oil temperature of the oil pan reaches 130 degrees in the third speed of the D range, the oil temperature of the torque converter is calculated as 145 degrees,
At this point, the control for lowering the oil temperature is executed. Since the actual allowable temperature of the torque converter is 150 degrees, there is no problem in performing the oil temperature lowering control at the time of 145 degrees with respect to the allowable temperature.

On the other hand, as shown in FIG. 6, at the fourth speed in the D range, the oil temperature of the torque converter when the oil temperature of the oil pan reaches 130 degrees is the allowable temperature of 150 degrees.
Calculated as degrees. That is, when the oil temperature of the torque converter reaches the allowable temperature, control for lowering the oil temperature is performed, and appropriate control according to the allowable temperature is performed.

[0011]

As described above, by setting the set value for the oil pan to 130 degrees,
14 below the allowable temperature of the torque converter of 150 degrees
At the time of 5 degrees, the control of the oil temperature drop is executed. Although there is no problem in that the oil temperature of the oil pan does not exceed the allowable temperature of the oil pan (135 degrees), as shown in FIG. 5, the set value of the oil pan is 130 degrees (therefore, the set value of the torque converter is 145 degrees), the execution time of the oil temperature lowering control is longer than the execution time of the oil temperature lowering control when the set value of the oil pan is 135 degrees (therefore, the set value of the torque converter is 150 degrees). About 10 minutes faster.

However, if the oil temperature lowering control is executed early as described above, the frequency of occurrence of vibration at the time of lock-up, shock at the time of shifting, etc. increases, and a situation arises in which the operability deteriorates. An object of the present invention is to solve the problems inherent in providing an oil temperature sensor only on the automatic transmission main body side and detecting the oil temperature of the torque converter from the measured value. is there. Specifically, an object of the present invention is to provide a control device for an automatic transmission that can prevent the occurrence of lock-up vibration and shift shock during execution of oil temperature reduction control.

[0013]

In order to achieve the above object, a control device for an automatic transmission according to the present invention controls a frictional engagement element of a transmission with a hydraulic pressure, and sets a predetermined shift map according to an operation state. Converter that performs shift control according to
The control device for an automatic transmission having a transmission OY
Oil temperature detection means for detecting the oil temperature in Lupine directly or indirectly, the oil temperature rise suppression means operative when said oil temperature becomes equal to or greater than the set oil temperature, according to set oil temperature to the speed Setting oil temperature changing means for changing the oil temperature.

As the oil temperature rise suppressing means, execution of lockup or downshift may be adopted. Further, the set oil temperature changing means can lower the set oil temperature as the gear position is higher.

[0015]

FIG. 7 is a schematic block diagram of an embodiment of a control device for an automatic transmission according to the present invention. The operation of the automatic transmission 20 is controlled by the automatic transmission controller 30. The automatic transmission 20 includes an oil temperature sensor 22 attached to an outlet or an inlet of a torque converter in an oil pan (not shown), and a signal Z1 representing the oil temperature in the oil pan detected by the oil temperature sensor 22. Is sent to the oil temperature setting means 32 of the controller 30.

The gear position of the automatic transmission 20 is determined by the controller 3
It is set by the shift speed setting means 34 of 0. The gear position setting means 34 sends a signal Z2 representing the gear position at that time to the oil temperature setting means 32. When receiving the signal Z2, the oil temperature setting means 32 sets a set value for the oil temperature of the oil pan according to the gear position represented by the signal Z2. In this case, the oil temperature setting means 32 sets such that the set value becomes lower as the gear position becomes higher. For example, the gear position represented by the signal Z2 is D range 3
If the speed is high, the setting value for the oil pan is set to 135 degrees, and if the D range is the fourth speed, it is set to 130 degrees.

The oil temperature setting means 32 stores in advance the difference (predetermined value) between the oil temperature of the oil pan and the oil temperature of the torque converter at each shift speed. This oil temperature difference is, for example, 15 degrees in the third speed of the D range and 20 degrees in the fourth speed of the D range.
The oil temperature setting means 32 continues to monitor the oil temperature in the oil pan based on the signal Z1 from the oil temperature sensor 22, for example,
As shown in FIG. 8, when the oil temperature of the oil pan becomes 135 degrees in the third range of the D range, a previously stored oil temperature difference of 15 degrees in the third range of the D range is added, and the oil temperature of the torque converter becomes It is determined that the temperature has reached 150 degrees, and an oil temperature suppression control start execution signal Z3 is sent to the oil temperature rise suppression means 24. In response to the signal Z3, the oil temperature rise suppression means 24 executes control such as lock-up and shift-down.

Similarly, as shown in FIG. 9, when the oil temperature of the oil pan becomes 130 degrees in the fourth range of the D range, the oil temperature difference of 20 degrees, which is the difference in the fourth range of the D range, is added to the oil temperature of the torque converter. Is determined to be 150 degrees, and a signal Z3 is sent to the oil temperature rise suppression means 24 to execute oil temperature rise suppression control. As means for detecting the oil temperature of the oil pan, instead of an oil temperature sensor for directly detecting the oil temperature, a cooling water temperature is used as a parameter, and the oil temperature is indirectly detected from the cooling water temperature. You may do so.

FIG. 10 is a flowchart of the operation of the control device for an automatic transmission according to the present invention. First, the oil temperature setting means 32 of the controller 30 determines the current gear position based on the signal Z2 from the gear position setting means 34.
Next, the oil temperature setting means 32 sets a set value for the oil pan according to the determined shift speed. This set value is set to decrease as the shift speed increases. For example, if the determined shift speed is the third speed in the D range, the set value is 13
5 degrees is set, and 130 degrees is set as the set value in the case of the D range 4th speed.

Next, the oil temperature setting means 32 adds the difference between the oil temperature of the oil pan and the oil temperature of the torque converter (this is determined for each gear) to the set value of the oil pan set for each gear. (A unique value) to obtain a set value for the torque converter. For example, 15 degrees is added to the set value of 135 degrees for the 3rd D range, and 20 degrees is added to the set value of 130 degrees for the 4th D range.

Next, it is determined whether or not the set value for the torque converter thus obtained is equal to or lower than the oil temperature detected by the oil temperature sensor. If the determination result is NO, the oil temperature is equal to or lower than the allowable temperature, and it is not necessary to perform control for lowering the oil temperature. On the other hand, the judgment result is YE
If S, it indicates that the oil temperature has reached the permissible temperature of the torque converter. Therefore, in order to lower the oil temperature, the oil temperature increase suppression means 24 controls the oil temperature increase suppression means 24 to perform lock-up or oil temperature increase suppression control. Execute shift down.

[0022]

Conventionally, regardless of the shift speed,
Since the allowable temperature of the oil temperature is set to a constant value, depending on the shift speed, control for lowering the oil temperature is performed at an oil temperature equal to or lower than the allowable temperature, and accordingly, lock-up vibration, shift shock, and the like occur. There was something. On the other hand, in the present invention, an appropriate allowable oil temperature is set for each shift speed. This allows
It is possible to solve the above-mentioned problem caused by the fact that the temperature of both the automatic transmission main body and the torque converter must be detected from only one oil temperature detecting means.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing a position of an oil temperature sensor in an automatic transmission.

FIG. 2 is a block diagram showing a schematic configuration of a conventional control device for an automatic transmission.

FIG. 3 is a graph showing allowable oil temperature values of an oil pan and a torque converter at a third speed in a D range in a conventional control device for an automatic transmission.

FIG. 4 is a graph showing allowable oil temperature values of an oil pan and a torque converter in a D range 4th speed in a conventional control device for an automatic transmission.

FIG. 5 is a graph showing allowable oil temperature values of an oil pan and a torque converter in a third range of a D range in a conventional control device for an automatic transmission.

FIG. 6 is a graph showing allowable oil temperature values of an oil pan and a torque converter in a D range 4th speed in a conventional automatic transmission control device.

FIG. 7 is a block diagram showing a schematic configuration of a control device for an automatic transmission according to the present invention.

FIG. 8 is a graph showing allowable oil temperature values of an oil pan and a torque converter in a third range of a D range in the control device for an automatic transmission according to the present invention.

FIG. 9 is a graph showing allowable oil temperature values of an oil pan and a torque converter in a D range 4th speed in the control device for an automatic transmission according to the present invention.

FIG. 10 is a flowchart of a control device for an automatic transmission according to the present invention.

[Explanation of symbols]

 Reference Signs List 2 Torque converter 4 Oil pan 6 Oil temperature sensor 10 Automatic transmission 12 Automatic transmission controller 14 Oil temperature sensor 16 Gear position setting means 20 Automatic transmission 22 Oil temperature sensor 24 Oil temperature rise suppression means 30 Controller for automatic transmission 32 Oil temperature setting means 34 Gear position setting means

Claims (4)

(57) [Claims] 1. A hydraulically controlled frictional engagement element of a transmission,
An oil temperature detecting means for directly or indirectly detecting an oil temperature in an oil pan of a transmission in a control device for an automatic transmission having a torque converter for performing a shift control according to a shift map predetermined according to an operation state. when the control device for an automatic transmission having an oil temperature rise suppression means operative when said oil temperature becomes equal to or greater than the set oil temperature, and a setting oil temperature changing means for changing in accordance with the set oil temperature to the speed . 2. The control device for an automatic transmission according to claim 1, wherein said oil temperature rise suppression means is lock-up. 3. The control device for an automatic transmission according to claim 1, wherein said oil temperature rise suppression means is a downshift. 4. The control device for an automatic transmission according to claim 1, wherein said set oil temperature changing means decreases the set oil temperature as the shift speed increases.