JP2778758B2 - Transmission control device for automatic transmission - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a shift control device for an automatic transmission in which a shift characteristic is appropriately changed.

(Prior Art) An automatic transmission is generally configured to include a torque converter with a lock-up clutch and a multi-stage transmission gear mechanism.

2. Description of the Related Art In recent automatic transmissions, it is common to change transmission characteristics as appropriate. In such an automatic transmission, usually, two shift characteristics, that is, a shift characteristic in, for example, the economy mode and a power mode in which the shift line is set to a higher vehicle speed side than the economy mode are prepared in advance, and for example, a manual selection is made. Thus, the shift control is performed with any desired shift characteristics.

Among those having a plurality of shift characteristics as described above, there has been proposed one that automatically changes the shift characteristics in accordance with the engine load. Japanese Patent Publication No. 57-8983 discloses that while normally performing shift control based on the economy mode, the engine load is equal to or greater than a predetermined reference value, for example, the throttle opening is 3 /
When the number becomes four or more, a gear shift control based on a power mode is disclosed. That is, the fact that the engine load is equal to or higher than a certain reference value means that a large engine output (torque) is required,
The power mode is automatically selected.

In addition, Japanese Patent Publication No. 51-22698 proposes a device in which the mode is switched to the power mode when the accelerator is suddenly depressed, that is, when the rate of change of the engine load exceeds a predetermined reference value. ing.

(Problems to be Solved by the Invention) However, in the above-mentioned publication, the reference value at the time of switching to the power mode is set to a certain fixed value, and therefore, in response to a driver's acceleration request. This makes it impossible to select an appropriate shift characteristic.

To explain this point more specifically, first, even if the operation state of the accelerator is the same, when the lock-up clutch is activated (engaged) or not (when disengaged), the acceleration of the vehicle is reduced. It will make a difference. That is, when the lock-up clutch is not operating, the torque increasing effect of the torque converter is exhibited,
The driving torque of the driving wheels becomes larger than when the lock-up clutch is operated, and a large acceleration can be obtained. Therefore, if the reference value is set on the basis of, for example, the time when the lock-up clutch is not operating, sufficient acceleration cannot be obtained when the lock-up clutch is operating. In other words, even if the driver operates the same accelerator, different accelerations will be exhibited when the lock-up clutch is activated and when it is not activated.

The present invention has been made in view of the above circumstances, and based on the premise that a shift line is changed to a higher vehicle speed side when an engine load becomes equal to or more than a predetermined reference value, a lock-up clutch is provided. It is an object of the present invention to provide a shift control device for an automatic transmission capable of achieving more appropriate shift characteristics in accordance with the operating state of the automatic transmission.

(Structure and operation of the invention) In order to achieve the above-described object, the present invention has the following first structure. That is, in a control device for an automatic transmission, comprising: a torque converter with a lock-up clutch, wherein the shift line is changed to a higher vehicle speed side when an engine load becomes equal to or more than a predetermined reference value. And a reference value changing means for changing the reference value based on an operation state.

To achieve the above object, the present invention has the following configuration as a second configuration. That is, in the control device for an automatic transmission, comprising a torque converter with a lock-up clutch, wherein the shift line is changed to a high vehicle speed side when the rate of change of the engine load is equal to or more than a predetermined reference value. It is provided with reference value changing means for changing the reference value based on the operating state of the up clutch.

(Effect of the Invention) According to the first aspect, it is possible to change the reference value for changing the speed change line in accordance with the operation state of the lock-up clutch, and to achieve more appropriate speed change characteristics.

With the configuration as described in claim 2, when the lock-up clutch is in operation where the torque increasing effect of the torque converter cannot be expected, the reference value is reduced, that is, the mode is more easily switched to the power mode, and the acceleration performance is improved. On the other hand, when the lock-up clutch is not operating, where the torque increasing effect of the torque converter can be expected,
By increasing the reference value, it is possible to obtain the same acceleration as when the lock-up clutch is operated.

According to the third aspect, it is possible to change the reference value for changing the speed change line in accordance with the operation state of the lock-up clutch, thereby achieving more appropriate speed change characteristics.

(Example) Hereinafter, an example of the present invention will be described with reference to the attached drawings.

In FIG. 1, reference numeral 1 denotes an Otto-type engine. The output (torque) of the engine 1 is transmitted to drive wheels (not shown) via an automatic transmission 2.

In the embodiment, the automatic transmission 2 includes a lock-up clutch.
It comprises a torque converter 3 having 3A and a multi-speed transmission gear mechanism 4 having four forward speeds and one reverse speed. The automatic transmission 2 is of a hydraulically operated type, and the lock-up clutch 3A is switched on and off by switching between excitation and demagnetization of a solenoid 5 incorporated in the hydraulic circuit. Further, by changing the combination of the excitation and the demagnetization of the plurality of solenoids 6 incorporated in the hydraulic circuit, the speed of the multi-speed gear mechanism 4 is changed.

In FIG. 1, U is a control unit for speed change control constituted by using a microcomputer. The control unit U receives signals from sensors or switches 21 to 23, and receives signals from the control unit U. The solenoids 5, 6
Is output to

The sensor 21 detects the throttle opening. The sensor 22 detects a vehicle speed. Switch 23
Is used to select a shift characteristic. In the embodiment, the operation is manually operated, and the economy mode shown in FIG. 2 is selected, the power mode shown in FIG. 3 is selected, and either of the two modes is selected. Are automatically selected (automatic switching) mode and a hold mode is selected. In the embodiment, when the economy mode is selected by the switch 23 or when the power mode is selected, the selected shift characteristic is fixed and the change is not performed. In the hold mode, as is known, the third speed is fixed at the D range, the second speed is fixed at the two ranges, and the first speed is fixed at the one range. The automatic mode is an object of the present invention. In the normal mode, the economy mode is selected, and when the engine load exceeds a predetermined reference value, the power mode is selected. The present invention can be applied when the economy mode is selected by the switch 23.

The outline of the control by the control unit U is as follows.
First, assuming that the automatic mode has been selected by the switch 23, basically, the economy mode shown in FIG. 2 is selected, and the shift control based on the economy mode is performed.

When the throttle opening indicating the engine load becomes equal to or more than a predetermined reference value, the mode is switched from the economy mode to the power mode, and the shift control is performed based on the power mode.

The reference value for switching to the power mode is set as a throttle opening. As shown in FIG. 4, the reference value is determined by a map value set using the vehicle speed VSP and the rate of change of the throttle opening ΔTVO as parameters. You. FIG. 4 shows that the vehicle speed as this parameter is DVSP (J) (J = 1,
, And the rate of change of the throttle opening is denoted by D △ TVO (I = 1, 2,...), And the throttle opening which is the reference value for shifting characteristic switching is DTVO (I , J)
As shown. That is, the actual throttle opening TVO
Is the reference value DTVO (I,
J) When it becomes above, the mode is switched from the economy mode to the power mode. In FIG. 4, when the vehicle speed is constant, the rate of change of the throttle opening △ TVO and the reference value DTV
FIG. 6 shows the correspondence tendency between O (I, J) and the correspondence tendency between the vehicle speed VSP and the reference value DTVO (I, J) when the rate of change of the throttle opening is fixed. This is shown in FIG.

A map for switching to the power mode (FIG. 4 shows two types of maps for ON (operation) and OFF of the lock-up clutch 3A. These maps are stored in each of the maps for ON and OFF. As shown in FIGS. 6 and 7, the reference value is set so that the ON time is smaller than the OFF time.

The reason for switching to the power mode as described above and then returning to the economy mode again is when the vehicle speed is greater than the predetermined return reference value and the throttle opening is smaller than the predetermined return reference value. It is said. As shown in FIG. 5, the return vehicle speed and the opening are stored as map values using the vehicle speed and the throttle opening as parameters. In FIG. 5, DVSP (J) (J =
1, 2,...) Are the vehicle speeds for searching the map,
DXTVO (I) (I = 1, 2,...) Is the throttle opening for searching the map, DRTVO (K, J) is the reference throttle opening for return, and DRVSP (K, J ) Is the reference vehicle speed for return. 8 to 11 show the correspondence tendency between the set parameters and the reference values for return in FIG. 5 (corresponding to FIGS. 6 and 7).

Next, the details of the control by the control unit U will be described.
This will be described with reference to the flowcharts of FIGS. 12A and 12B. In the following description, P indicates a step.

First, the P flag is reset to 0 in the initialization of P1. When the P flag is 1, the power mode is selected, and when the P flag is 0, the economy mode is selected.

In P2, the throttle opening T detected by the sensors 21 and 22 is determined.
And the vehicle speed VSP are read, and the throttle opening change rate △ T
VO is determined by differentiating TVO (determining the difference from previously detected TVO).

At P3, it is determined whether or not the lock-up clutch 3A is ON (the ON detection switch may be separately provided). If YES in this determination of P3, lock-up ON
Map is selected (corresponding to FIG. 4), and if the determination in P3 is NO, a map for lock-up OFF (corresponding to FIG. 4) is selected. After this P4 or P5, at P6 the fourth
Addresses I, J and K on the map shown in FIG. 5 and FIG. 5 are respectively set to 1.

In P7, the throttle opening change rate △ TVO
It is determined whether or not it is smaller than $ TVO (I) on the map shown in the figure. If the determination in P7 is NO, then in P8 I
And P7 is determined again. In this way, by the processes of P7 and P8, △ TVO (I) in FIG. 4 corresponding to the current throttle opening change rate △ TVO is determined. Similarly, the current vehicle speed VSP is obtained by the processing of P9 and P10.
The vehicle speed DVSP (J) shown in FIGS. 4 and 5 corresponding to FIG.

In P11, D △ TVO (I) obtained as described above is
It is determined whether or not the current throttle opening TVO is larger than the stored value of FIG. 4 based on the DVSP (J), that is, the set reference value DTVO (I, J). If the determination in P11 is YES, the P flag is set to 1 in P12, and if the determination in P11 is NO, the P flag is reset to 0 in P13.

After P12 or P13, DXTVO (K) in FIG. 5 corresponding to the current throttle opening TVO is determined by the processing of P21 and P22 in FIG. 12B. In the determination of P23, when the P flag is 0, the selection of the power mode is turned off in P24 (shift control based on the economy mode), and when the P flag is 1, the selection of the power mode is turned on in P25. (Shift control based on the power mode).

After P25, the processing of P26 to P29 is performed, which corresponds to the processing of whether or not to return to the economy mode. That is, first, at P26, the current vehicle speed VSP and the throttle opening TVO are read. And the current vehicle speed VSP is 5th
It is larger than the reference vehicle speed DRVSP (K, J) for return in the figure (when the determination in P27 is YES) and the current throttle opening
When TVO is smaller than the reference opening for return DRTVO (K, J) in FIG. 5 (when the determination in P28 is YES), the P flag is reset to 0 in P29 (return to economy mode). . It should be noted that, in the determination of either P27 or P28, NO
Returns to P23.

Although the embodiment has been described above, a change rate of the engine load, for example, a throttle opening degree change rate may be used as the reference value for switching to the power mode instead of the engine load. In this case, the rate of change as the reference value is preferably set using the throttle opening and the vehicle speed as parameters (the rate of change as the reference value decreases as the throttle opening increases, and the reference value increases as the vehicle speed increases). In such a manner that the rate of change becomes smaller).
Further, the speed change line for switching to the high vehicle speed side may be a part of the speed change line (for example, only the speed change line for switching the second speed and the third speed).

[Brief description of the drawings]

FIG. 1 is an overall system diagram showing one embodiment of the present invention. FIG. 2 is a diagram showing an example of a shift characteristic in the economy mode. FIG. 3 is a diagram showing an example of a shift characteristic in a power mode. FIG. 4 is a diagram showing a map for a power mode set. FIG. 5 is a diagram showing a map for resetting a power mode. 6 and 7 are diagrams showing the setting tendency of the map shown in FIG. 8 to 11 are diagrams showing the setting tendency of the map shown in FIG. 12A and 12B are flowcharts showing a control example of the present invention. U: Control unit 1: Engine 2: Automatic transmission 3: Torque converter 3A: Lock-up clutch 4: Multi-stage transmission gear mechanism 6: Solenoid (for gear shifting) 21: Sensor (throttle opening) 22: Sensor (vehicle speed) 23: Switch (for selecting gear shifting characteristics)

Claims (3)

(57) [Claims] 1. A control device for an automatic transmission, comprising: a torque converter with a lock-up clutch, wherein a shift line is changed to a high vehicle speed side when an engine load becomes equal to or more than a predetermined reference value. A shift control device for an automatic transmission, comprising: a reference value changing unit that changes the reference value based on an operation state of an up clutch. 2. The automatic transmission according to claim 1, wherein the reference value changing means changes the reference value to a smaller value when the lock-up clutch is operated than when the lock-up clutch is not operated. Control device. 3. A control device for an automatic transmission, comprising: a torque converter with a lock-up clutch, wherein a shift line is changed to a higher vehicle speed side when a change rate of an engine load becomes equal to or more than a predetermined reference value. A shift control device for an automatic transmission, comprising: a reference value changing unit that changes the reference value based on an operation state of the lock-up clutch.