JP2002039365A - Control device for automatic transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent excess rise of a rotational frequency of an engine with the usage of running resistance of a vehicle on an uphill road and thereby to prevent lowering of driving force. SOLUTION: The automatic transmission 2 equipped with a torque converter capable of locking-up is used for a vehicle having a diesel engine 1 as a driving source of which rotational frequency to torque output property rapidly lowers at high rotation side exceeding a maximum torque range. The control device 10 is equipped with hill climbing control means 11 to 15 for locking-up the torque converter during hill climbing of the vehicle. Thus, the rise of the rotational frequency of the engine to the high rotation side by which the torque output deteriorates from the maximum torque range is controlled by the transmission of the running resistance to the engine by locking-up of the torque converter. Thus, hill climbing with the usage of the maximum torque range is possible.

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 ensuring the running performance of a vehicle on an uphill road.

[0002]

2. Description of the Related Art Shift control of an automatic transmission operates a solenoid of a hydraulic control device incorporated in the automatic transmission by output of a shift signal from an electronic control device, thereby controlling various valves in a hydraulic circuit. The frictional engagement element of the transmission mechanism is engaged and disengaged, and at the same time, lockup control of the torque converter is performed by engagement and disengagement of the lockup clutch and slip control by the same means. The output of the shift signal and the lock-up on / off and slip signals from the electronic control unit is normally performed based on a shift map. The shift map should be appropriately adapted to the traveling mode of the vehicle. , During normal running, economy running, heavy load running, and the like. Among these various running modes, in the uphill running state, the actual vehicle acceleration is a certain value (calibration data) with respect to the vehicle acceleration on a flat road estimated by the accelerator opening and the engine speed or the engine torque signal. When it becomes smaller, it is regarded as uphill and the shift map for uphill is switched.

[0003]

By the way, in the case of a vehicle using a gasoline engine as a power source, as shown in FIG. 5 (B), the characteristic of the engine speed versus the torque output is generally flat. Conventionally, in an automatic transmission, the lock-up (L-up) is turned off and the engine speed is increased in order to increase the driving force when climbing a slope because the torque decrease at a rotation speed exceeding the range is gradual. The control is performed so as to use the region where the engine torque can be output most. More specifically, such control of the automatic transmission is performed by switching the shift map of the electronic control unit. For example, when climbing a hill, the map shown in FIG. Switching to a map in which such a lockup area is not set has been performed.

[0004] However, when such control is performed in a vehicle using a diesel engine as a power source, the diesel engine generally has an engine speed versus torque output characteristic of a gasoline engine as shown in FIG. There is a tendency for the torque to decrease markedly at speeds exceeding the maximum torque range, and turning off lock-up during climbing on such a diesel vehicle causes the engine speed to rise excessively and reduce the engine torque to the maximum. A phenomenon occurs in which the vehicle goes out of the output range and the uphill slope is rather slow.

In view of such circumstances, the present invention provides a control device for an automatic transmission that prevents a decrease in driving force by suppressing an excessive increase in the engine speed by utilizing the running resistance of a vehicle on an uphill road. The purpose is to provide.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to a vehicle powered by an engine in which the characteristic of the number of revolutions versus torque output sharply decreases on the high revolution side exceeding the maximum torque range. Used in a control device of an automatic transmission including a torque converter that can be locked up, when the vehicle climbs a hill, the torque converter is locked up,
The present invention is characterized in that it has a hill-climbing control means for suppressing a shift of the engine rotation from the maximum torque region to a high rotation side where the torque output decreases.

More specifically, it is more effective that the hill-climbing control means locks up the torque converter by determining the hill-climbing road when the engine speed is equal to or higher than a predetermined value and the torque is less than the predetermined value. It is.

More specifically, the climbing control means may include a traveling resistance comparing means for judging an ascending road by comparing with a flat road based on the traveling resistance.

In the above configuration, the lockup of the torque converter by the uphill control means may be performed by selecting an uphill road map by switching a shift map.

In the above configuration, it is also effective that the uphill road map has a lock-up area set in accordance with the shift speed.

In the above configuration, the lock-up region may be set to cover at least the entire high speed stage including the highest speed stage.

[0012]

According to the structure of the first aspect of the present invention, acceleration in climbing a hill is improved by traveling in a region where the engine torque is high, so that a smooth uphill traveling is possible. In addition, the differential rotation of the torque converter can be reduced in the case of slip control or eliminated in the case of complete lock-up by lock-up at the time of climbing when traveling load increases, so that the oil temperature of the automatic transmission hydraulic oil can be reduced. Ascent can be prevented.

Next, in the configuration of the second aspect, the determination of the uphill road for locking up the torque converter is appropriately performed based on the relationship between the engine speed and the torque.

According to the third aspect of the present invention, the uphill road is determined by comparing the road with a flat road based on the running resistance, so that the determination of the uphill road is more appropriate.

According to the fourth aspect of the present invention, since the lockup of the torque converter by the uphill control means is performed by switching the shift map, the output of the control device is obtained in the same manner as the conventional lockup control. Uphill control can be performed without changing the system configuration of the system.

In the configuration of the fifth aspect, the setting of the uphill road map itself used for uphill control can be performed in the same manner as the conventional shift map.

Further, in the structure of the sixth aspect, it is possible to eliminate the lock-up release at the time of a rapid change in the throttle opening and prevent the engine rotation from increasing in the torque-down direction at the time of kick-down.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a system configuration of a control system of an automatic transmission according to an embodiment of the present invention. As shown in the figure, an engine (E / G) 1 and an automatic transmission (T / M) 2 connected thereto have an electronic control unit (ECU) 10 for the control and various information for the control. Sensors 3 to 8 for acquisition are provided. The automatic transmission 2 includes a hydraulic control device for controlling the friction engagement elements and the torque converter built therein, but these are not shown.

Each of the sensors 3 to 8 in this control device includes:
Usually, the sensor (E / E / E / E / E / E) is a sensor provided for controlling the automatic transmission.
G) A rotation speed sensor 3, a transmission (T / M) input rotation speed sensor 4 for detecting the rotation speed of the turbine output shaft of the torque converter of the automatic transmission 2 or the input shaft of the transmission mechanism, and the output shaft of the transmission mechanism or connected thereto. A vehicle speed sensor 5 for detecting the rotation speed of the output element, a main throttle opening sensor 6 for detecting the engine load from the intake system of the engine 1, and a sub-throttle for similarly detecting the engine load during traction control from the intake system of the engine 1. It comprises an opening sensor 7 and a brake switch (S / W) 8 for detecting the operation of the brake from the operation of the brake pedal of the vehicle. All of the signals S _{1 to} S ₆ from these sensors are output to the electronic control unit 10.

Next, the electronic control unit 10 refers to the engine torque map based on the throttle opening signals S ₄ and S ₅ from the main throttle opening sensor 6 or the sub throttle opening sensor 7, and at that time, Reference acceleration calculating means 11 for calculating a reference acceleration from the relationship between the engine speed and the torque corresponding to the throttle opening, and an actual acceleration for calculating the actual acceleration of the vehicle by differentiating the vehicle speed signal S ₃ from the vehicle speed sensor 5. acceleration calculating means 12, the reference acceleration calculating means running resistance is estimated based on the reference acceleration value S ₇ calculated in 11, and the running resistance in each case based on the actual acceleration value S ₈ calculated by the actual acceleration calculating unit 12 from the running resistance estimation unit 13, reference acceleration value S ₇ running resistance value and the actual acceleration value running resistance estimating means 13 the running resistance value based on S ₈ based on estimating the Running resistance comparing means 14 for comparing based on the signal S _9, the traveling determining shift map to the shift map by the selection signal S _{1 0} from the resistance comparison unit 14 determination unit 15, and selected hydraulic control device based on the shift map The speed change output means 16 outputs a drive signal S _{12 to the} solenoid. In this embodiment, since the estimation of the engine torque is performed by the map data as described above, illustration of the means is omitted.

On the premise of such a system configuration, the uphill control according to the present invention is performed. In the uphill control, the torque converter is locked up by the uphill control means, and the traveling load of the vehicle is utilized. The shift of the engine speed from the maximum torque region to the high rotation side where the torque output decreases is suppressed. More specifically, when the engine speed is equal to or more than a predetermined value and the torque is less than the predetermined value, the uphill control means performs control to determine an uphill road and lock up the torque converter. Therefore, if a torque sensor for actually measuring the engine torque can be provided, it is not necessary to estimate the torque from the relationship between the throttle opening and the engine speed described later. Further, in the present embodiment, a configuration is adopted in which the determination of the uphill road is made by comparing the running resistance of the flat road with the running resistance of the uphill road by the running resistance comparing means.

FIG. 2 is a flow chart showing the content of uphill control by the electronic control unit 10. The initial step S1 in this flow is for discriminating whether or not traction control is being performed. If this determination is made,
In the next step S2, the engine torque is estimated from the map of the engine speed and the engine output torque using the throttle opening as a parameter based on the main throttle opening. If the determination in step S1 is not satisfied,
In step 3, the engine torque is estimated from another map of the engine speed and the engine output torque using the throttle opening as a parameter based on the sub throttle opening.

In the next step S4 following this distinction, a reference acceleration for running on a flat road is calculated. This calculation is obtained from the estimated value of the engine torque previously estimated and the running resistance on a flat road. In a next step S5, an actual acceleration is calculated. The two accelerations thus obtained are compared, and it is determined whether or not the value is smaller than a specified value a, that is, actual acceleration−reference acceleration <a (m / s ² ). The specified value a used for this determination is a reference value for uphill road determination set based on the calibration data. When the uphill determination is made in step S6, the elapsed time after the determination in step S6 is made is determined in next step S7. This timer process is omitted in this flow. Initially, this determination is not satisfied, so the process returns to the first determination in step S1, and this routine is repeated thereafter. Step S
When the elapse determination of step 7 is established, an uphill road map is selected in step S8, and a shift output corresponding to the uphill road map is made, thereby entering the uphill control state.

When the vehicle is running in the uphill control state, the engine
When the excessive rotation state is eliminated, in step S6 on the way,
Is not established, so in that case, step
In S9, another climbing road judgment comparing both accelerations is performed.
Is larger than another specified value b different from the above predetermined value.
Whether or not, that is, actual acceleration−reference acceleration> b (m / s
^Two), And if this judgment is not satisfied,
The uphill control state is continued. Rules used in this judgment
The value b is also the calibration data as in the case of the specified value a.
Uphill road with a value larger than the specified value a set based on the data
This is the reference value for disconnection. Then, the determination in step S9 is established.
Then, in the next step S10, the determination in step S9 is established.
A later elapsed time is determined. About this timer process
Are also omitted in this flow. Initially, this decision was
Since the condition is satisfied, the process returns to the initial determination in step S1.
Repeat this routine below. Over time,
When the progress judgment of step S10 is established, the process proceeds to step S11.
Select a flatter road map and generate a shift output in accordance with it.
As a result, a flat road control state is set.

As described above, in this control, the uphill control is started when the acceleration comparison value is less than the predetermined value a, and once this state is entered, the uphill control is performed even after the acceleration comparison value exceeds the predetermined value a. Is continued, and when the acceleration comparison value exceeds the larger predetermined value b, a process of releasing the uphill control and returning to the flat road control is performed.

FIGS. 3 and 4 show an example of a shift map which is switched and selected by the above control. As can be seen by comparing these figures, in this example, 3 → 4 upshift and 4 →
In the map for flat road control shown in FIG. 3, the lock-up on line (shown by a thin solid line in FIG. 3) is higher than the upshift shift line (also shown by a thick solid line) with respect to the shift line of 3-downshift. The lock-up off line (also shown by the thin dotted line) is set to be shifted to the high rotation side with respect to the downshift shift line (also shown by the thick broken line). In the hill-climbing control map shown in FIG. 4, the up-down shift line and the lock-up on / off line are both set to coincide. As a result, for example, while traveling in the fourth speed lock-up on state by flat road control,
When the accelerator is turned on when the vehicle goes uphill, as shown by the arrow in FIG. 3, the throttle opening increases to 4 →
A lock-up off state occurs before the 3 downshift occurs, and in a state in which fluid slippage in the torque converter is allowed, the engine rotation increases in accordance with the throttle opening, so that the torque decreases. The rotation speed will increase. On the other hand, according to the present embodiment, even if the throttle opening increases due to the accelerator-on operation in the same state, the shift map is switched to change the 4 → 3 downshift as shown by the arrow in FIG. The lock-up on state continues until the vehicle crosses the line, and the lock-up on state is maintained even after shifting to the 3rd speed, so the engine speed is regulated by the output speed due to the running load of the vehicle and the engine speed rises immediately in response to the throttle opening. Since this is not shown, a sudden increase in engine rotation in the direction of torque reduction is prevented.

Thus, according to this embodiment, acceleration in climbing a hill can be improved by traveling in a region where the engine torque is high, and smooth traveling on an uphill road can be performed. In addition, the differential rotation of the torque converter can be reduced in the case of slip control or eliminated in the case of complete lock-up by lock-up when climbing a hill where traveling load increases, preventing the oil temperature of the automatic transmission hydraulic oil from rising. can do.

Further, the determination of the uphill road for locking up the torque converter is made based on the relationship between the engine speed and the torque and by comparison with a flat road based on the running resistance. Become. Further, since the lock-up of the torque converter by the uphill control means is performed by switching the shift map as illustrated in FIGS. 3 and 4, the output system of the control device is similar to the conventional lock-up control. Uphill control can be performed without changing the system configuration. In addition, the setting of the uphill road map itself used for uphill control can be performed in the same manner as the conventional shift map. Further, it is possible to eliminate the lock-up release at the time of a rapid change in the throttle opening, thereby preventing the engine rotation from increasing in the torque down direction at the time of kick down.

Although the present invention has been described in detail based on one embodiment in which the present invention is applied to a control device having a system configuration including conventional sensors, the present invention includes a sensor such as a torque sensor capable of actually measuring engine torque. In the system configuration,
It is possible to adopt a simpler control form in which the process of estimating the engine torque is eliminated. Further, the present invention is suitable for use in diesel vehicles, but the application of the present invention is not necessarily limited to this.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a system configuration of an embodiment of a control device for an automatic transmission according to the present invention.

FIG. 2 is a flowchart illustrating a hill-climbing control process performed by the control device.

FIG. 3 is a flat road shift map selected by the uphill control process.

FIG. 4 is an uphill road shift map selected by the uphill control process.

FIG. 5 is a torque diagram showing general torque characteristics comparing a gasoline engine and a diesel engine.

FIG. 6 is an uphill road shift map used for conventional uphill control.

[Explanation of symbols]

Reference Signs List 1 engine 10 electronic control unit 11, S4 reference acceleration calculation means (uphill control means) 12, S5 actual acceleration calculation means (uphill control means) 13 running resistance estimation means (uphill control means) 14, S6, S9 running resistance comparison means ( Uphill control means) 15, S8, S11 Shift map determination means (uphill control means)

Claims (6)

[Claims] 1. Control of an automatic transmission having a lockup-capable torque converter, which is used in a vehicle powered by an engine whose speed-torque output characteristic sharply decreases on a high rotation speed exceeding a maximum torque region and has a lock-up torque converter. An automatic transmission, comprising: a climbing control unit that locks up a torque converter during climbing of a vehicle to suppress a transition of engine rotation from a maximum torque region to a high rotation side where torque output decreases. Control device. 2. The uphill control means determines an uphill road and locks up the torque converter when the engine speed is equal to or higher than a predetermined value and the torque is lower than the predetermined value.
The control device for an automatic transmission according to claim 1. 3. The control device for an automatic transmission according to claim 1, wherein said uphill control means includes running resistance comparing means for judging an uphill road by comparing with a flat road based on running resistance. 4. The control device for an automatic transmission according to claim 1, wherein the lock-up of the torque converter by the uphill control means is performed by selecting an uphill road map by switching a shift map. 5. The control device for an automatic transmission according to claim 4, wherein the uphill road map is a map in which a lockup area is set in accordance with a shift speed. 6. The control device for an automatic transmission according to claim 5, wherein the lock-up region is set in an entire region of a high speed stage including at least a highest speed stage.