WO2012105527A1

WO2012105527A1 - Control device for automatic transmission

Info

Publication number: WO2012105527A1
Application number: PCT/JP2012/052060
Authority: WO
Inventors: 中村　幸司; 卯京小形; 祐一郎竹森
Original assignee: 本田技研工業株式会社
Priority date: 2011-02-01
Filing date: 2012-01-31
Publication date: 2012-08-09

Abstract

In order to prevent the vehicle speed from stagnating or decreasing when a vehicle with little drive power such as a compact car is traveling uphill, a control device (5) for an automatic transmission has a torque converter (3) equipped with lockup clutch (35) that switches between engaging/disengaging an input element (21) linked to a drive source (1) and an output element (22) linked to an automatic transmission (2). In addition, this control device is equipped with: a lockup control means (55) that controls the switching of the lockup clutch (35) between engagement/disengagement, and a road surface slope calculation means (52) that calculates the slope of the road surface on which the vehicle is traveling. When the vehicle is traveling with the lockup clutch (35) disengaged and the slope (S) for the road surface calculated with the road surface slope calculation means (52) is at or higher than a first prescribed value (S1), the lockup control means (55) prevents the engagement of the lockup clutch (35).

Description

Control device for automatic transmission

The present invention relates to a control device for an automatic transmission that controls switching of engagement / disengagement of a lock-up clutch of a torque converter provided in the automatic transmission according to a traveling state of the vehicle.

Some torque converters included in automatic transmissions mounted on vehicles are accompanied by a lock-up clutch (hereinafter also referred to as “LC”). A vehicle including such a torque converter with a lock-up clutch is provided with a lock-up control means for controlling switching of engagement / disengagement of the lock-up clutch, as shown in Patent Document 1, for example. ing. This lock-up control means performs control for engaging the lock-up clutch in the torque converter in a predetermined operation region during traveling of the vehicle. Thereby, it is possible to improve the fuel economy (fuel consumption) of the vehicle while keeping the engine speed low.

The lockup control means as described above controls the engagement / disengagement of the lockup clutch and the engagement amount (engagement amount) at the time of engagement based on the vehicle speed and the accelerator pedal opening (or throttle opening). A control map (LC map) for controlling the lockup clutch based on the control map.

However, in a vehicle equipped with the lockup control means as described above, if the lockup clutch is engaged on an uphill road with a large road gradient, torque amplification by the lockup clutch is not performed. Therefore, even when the lockup clutch is engaged at a high vehicle speed, there is a problem that the traveling speed of the uphill road (commercial characteristics of the uphill road traveling) deteriorates because the vehicle speed immediately stagnates or decreases thereafter. . This is not a problem with a vehicle having a large driving force (output) of a driving source such as an engine, but becomes remarkable with a vehicle having a small driving force such as a small vehicle. A similar problem occurs when the vehicle enters an uphill road with the lock-up clutch engaged. Further, when the vehicle enters the uphill road with the lock-up clutch engaged, the lock-up clutch engagement amount control (slip control) is performed as the vehicle speed decreases, so that a slip region is generated in the lock-up clutch. As a result, the amount of heat generated by the friction material of the lockup clutch increases, which may lead to deterioration of the durability of the lockup clutch.

Japanese Patent No. 4260445

The present invention has been made in view of the above points, and its purpose is to effectively prevent the vehicle speed from stagnating or decreasing when traveling on an uphill road, particularly in a vehicle having a small driving force such as a small car, An object of the present invention is to provide an automatic transmission control device capable of improving the durability of a lockup clutch.

In order to solve the above problems, the present invention provides an engagement / disengagement between an input element (21) connected to the drive source (1) and an output element (22) connected to the automatic transmission (2). A control device (5) for an automatic transmission having a torque converter (3) provided with a lock-up clutch (35) for switching between the engagement and disengagement of the lock-up clutch (35). An up control means (55), and a road surface slope calculating means (52) for calculating the slope of the road surface on which the vehicle is traveling. The lockup control means (55) is provided with a lockup clutch (35). If the road surface gradient (S) calculated by the road surface gradient calculating means (52) becomes equal to or higher than the first predetermined value (S1) during traveling in the disengaged state, the lockup clutch (35 ) Control to prohibit engagement And wherein the Ukoto.

As described above, when the lock-up clutch is engaged when the vehicle is traveling on a road surface with a large slope (uphill road), the vehicle speed is stagnated or decreased, and the traveling performance of the uphill road is deteriorated. There is. This problem is particularly noticeable in a vehicle having a small driving force such as a small vehicle. Therefore, in the control device for an automatic transmission according to the present invention, when the road surface gradient becomes equal to or higher than the first predetermined value while the vehicle is running without engaging the lock-up clutch, Control to prohibit engagement was performed. Thereby, when the vehicle is traveling on a gradient equal to or higher than the first predetermined value, the non-engagement state of the lockup clutch can be continued, so that it is possible to effectively prevent the vehicle speed from stagnating or decreasing. . Therefore, it is possible to improve the traveling performance on the uphill road. Further, since the engagement amount control (so-called slip control) of the lockup clutch is not performed while the engagement of the lockup clutch is prohibited, the heat generation of the friction material of the lockup clutch can be suppressed. Therefore, since the lockup clutch can be protected, the durability of the lockup clutch can be improved.

Further, in this case, the lockup control means (55) prohibits the engagement of the lockup clutch (35), and the road surface gradient (S) calculated by the road surface gradient calculation means (52) is the first. When it becomes equal to or smaller than the second predetermined value (S2) smaller than the predetermined value (S1), control for releasing the prohibition of the engagement of the lockup clutch (35) may be performed.

According to this configuration, when the slope of the road surface on which the vehicle travels is equal to or less than the second predetermined value, the prohibition of the lock-up clutch is released, thereby improving the traveling performance of the uphill road and the fuel efficiency. Can contribute to both. In addition, the difference between the gradient condition (first predetermined value) for prohibiting the engagement of the lockup clutch and the gradient condition (second predetermined value) for releasing the prohibition allows the engagement of the lockup clutch. It is possible to prevent a hunting phenomenon in which prohibition and release are frequently repeated.

The present invention also provides a lock-up clutch that switches engagement / disengagement between an input element (21) connected to the drive source (1) and an output element (22) connected to the automatic transmission (2). 35) a control device (5) for an automatic transmission having a torque converter (3) with a lockup control means (55) for controlling switching of engagement / disengagement of the lockup clutch (35). And road surface gradient calculating means (52) for calculating the gradient of the road surface on which the vehicle is traveling, and the lockup control means (55) travels with the vehicle engaged with the lockup clutch (35). When the road surface gradient (S) calculated by the road surface gradient calculating means (52) is equal to or higher than the first predetermined value (S1), the control for releasing the engagement of the lockup clutch (35) is performed. It is characterized by performing.

When a vehicle running with the lock-up clutch engaged enters the uphill road, if the lock-up clutch is kept engaged as it is, the vehicle speed is stagnated or decreased, so The merchandise of road driving) deteriorates. This is particularly noticeable in small vehicles with a small driving force. Therefore, in the control apparatus for an automatic transmission according to the present invention, when the road surface gradient exceeds the first predetermined value while the vehicle is running with the lock-up clutch engaged, the lock-up clutch Control to release the engagement was performed. Thereby, when the vehicle enters an uphill road having a gradient equal to or higher than the first predetermined value, it is possible to effectively prevent the vehicle speed from being stagnated or lowered by releasing the engagement of the lockup clutch. Therefore, it is possible to improve the traveling performance on the uphill road. Further, by disengaging the lockup clutch when the road surface gradient is equal to or greater than the first predetermined value, the lockup clutch can be disengaged before the vehicle speed decreases. Thereby, the vehicle body fluctuation | variation accompanying engagement cancellation | release of a lockup clutch can be suppressed small, and it can prevent that shocks, such as a vibration and a noise, are transmitted to a vehicle body or a passenger | crew.

In this case, after the lockup control means (55) releases the engagement of the lockup clutch (35), the road surface gradient (S) calculated by the road surface gradient calculation means (52) is the first. When it becomes equal to or smaller than a second predetermined value (S2) smaller than the predetermined value (S1), control for engaging the lockup clutch (35) may be performed.

According to this configuration, by engaging the lock-up clutch after the slope of the road surface on which the vehicle travels is equal to or less than the second predetermined value, it contributes to both improvement of traveling performance and fuel efficiency on the uphill road. be able to. In addition, by providing a difference between the gradient condition for releasing the lockup clutch (first predetermined value) and the gradient condition for engaging (second predetermined value), the lockup clutch is engaged and released. It is possible to prevent a hunting phenomenon that is frequently repeated.
In addition, the reference code | symbol described in the parenthesis above has illustrated the code | symbol attached | subjected to the corresponding component in embodiment mentioned later for reference.

According to the present invention, it is possible to effectively prevent the stagnation or decrease of the vehicle speed when the vehicle is traveling on an uphill road, and to improve the durability of the lockup clutch.

It is the schematic which shows the drive system of the vehicle provided with the control apparatus of the automatic transmission in one Embodiment of this invention. It is a functional block diagram of CVT-ECU. It is a figure which shows the control flow (main flow) in engagement control of a lockup clutch. It is a figure which shows the control flow (subroutine) of the determination procedure of an uphill LC-OFF flag.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a schematic view showing a drive system of a vehicle provided with a control device for an automatic transmission according to an embodiment of the present invention. As shown in FIG. 1, the vehicle of this embodiment includes an engine 1, an automatic transmission 2, a FI-ECU 4 that is a control means for controlling the engine 1, and a control for controlling the automatic transmission 2. CVT-ECU 5 as means and a hydraulic control device 6 for controlling the hydraulic pressure supplied to the automatic transmission 2 are provided. The automatic transmission 2 includes a fluid-type torque converter 3 having a lock-up clutch 35 and a belt-type continuously variable transmission mechanism (CVT) 10 connected to the engine 1 via the torque converter 3. . The hydraulic control device 6 is a device for supplying hydraulic pressure for performing drive control of the torque converter 3, engagement pressure control of the lockup clutch 35, and engagement pressure control of the CVT 10.

Rotation of the engine 1 is output to the crankshaft (output shaft) 21. The rotation of the crankshaft 21 is transmitted to the main shaft 22 of the automatic transmission 2 via the torque converter 3. The torque converter 3 transmits torque via a fluid (hydraulic oil), and includes a front cover 31, a pump impeller (pump impeller) 32 formed integrally with the front cover 31, and the front cover 31. A turbine impeller (turbine runner) 33 disposed between the pump impeller 32 and the pump impeller 32, and a one-way clutch 36 interposed between the pump impeller 32 and the turbine impeller 33. And a stator impeller 34 rotatably supported on a stator shaft (fixed shaft) 38. The crankshaft 21 is connected to the pump impeller 32 of the torque converter 3 via the front cover 31, and the turbine impeller 33 is connected to the main shaft (input shaft of the automatic transmission 2) 22.

In addition, a lockup clutch 35 is provided between the turbine impeller 33 and the front cover 31. Engagement of the lockup clutch 35 is controlled by hydraulic control (lockup control) of the hydraulic control device 6 based on a command of the CVT-ECU 5. In this lock-up control, the lock-up clutch 35 is engaged (fastened) with the front cover 31 by being pressed toward the inner surface of the front cover 31, and is engaged with the front cover 31 by being released. Canceled. In a container formed by the front cover 31 and the pump impeller 32, hydraulic oil (CVTF: Continuously Variable Variable Transmission Fluid) is sealed.

When the lockup control is not performed, relative rotation between the pump impeller 32 and the turbine impeller 33 is allowed. In this state, when the rotational torque of the crankshaft 21 is transmitted to the pump impeller 32 via the front cover 31, the hydraulic oil that fills the container of the torque converter 3 is pumped by the rotation of the pump impeller 32. Circulation from the car 32 to the turbine impeller 33 and then to the stator impeller 34. As a result, the rotational torque of the pump impeller 32 is hydrodynamically transmitted to the turbine impeller 33, and during this time, torque amplification is performed to drive the main shaft 22. At this time, the stator impeller 34 bears a reaction force of the torque (hereinafter referred to as “stator reaction force”).

On the other hand, during the lock-up control, the lock-up clutch 35 is engaged, and the front cover 31 is not mechanically rotated from the front cover 31 to the turbine impeller 33 via hydraulic oil. The turbine impeller 33 rotates as a unit, and the rotational torque of the crankshaft 21 is directly transmitted to the main shaft 22.

The automatic transmission 2 according to this embodiment includes a belt-type continuously variable transmission (CVT) 10 as a transmission mechanism for changing the rotation transmitted from the main shaft 22 to the counter shaft 23. A belt type continuously variable transmission mechanism (hereinafter referred to as “CVT”) 10 includes a drive pulley 11 that rotates integrally with the main shaft 22, a driven pulley 12 that rotates integrally with the counter shaft 23, and these drive pulleys 11. An endless metal V-belt 13 is provided between the driven pulley 12 and the endless metal. In this belt type continuously variable transmission mechanism 10, the hydraulic pressure control device 6 controls the hydraulic pressure supplied to the cylinder chamber 11 a on the drive pulley 11 side and the cylinder chamber 12 a on the driven pulley 12 side (drive side pressure and driven side pressure) to drive the belt type continuously variable transmission mechanism 10. A lateral pressure is applied to the pulley 11 and the driven pulley 12 so that the V-belt 13 does not slip. Further, the drive side pressure and the driven side pressure are controlled to be different from each other, the groove widths of the drive pulley 11 and the driven pulley 12 are appropriately changed, and the winding diameter of the V belt 13 is changed to thereby change the drive pulley. Control is performed to change the speed ratio between the pulley 11 and the driven pulley 12 steplessly.

Thereby, the rotational torque of the main shaft 22 is transmitted to the counter shaft 23 via the CVT 10. Further, the rotational torque of the counter shaft 23 is transmitted to the drive wheels through a gear train and a differential mechanism (not shown).

The hydraulic control device 6 controls the transmission gear ratio supplied to the countershaft 23 from the main shaft 22 by controlling the hydraulic pressure supplied to the

cylinder chambers

11 a and 12 a of the CVT 10. Further, by supplying hydraulic oil of hydraulic pressure to the pump impeller 32 of the torque converter 3, the torque converter slip ratio ETR indicating how much the rotational drive of the crankshaft 21 is transmitted to the main shaft 22 is controlled, and the vehicle The engagement / disengagement of the lock-up clutch 35 is performed by switching the supply / stop of the hydraulic pressure supplied to the oil chamber (not shown) of the lock-up clutch 35 based on the travel state.

In addition, the vehicle of this embodiment is provided with various sensors. That is, in the vicinity of the crankshaft 21, a crankshaft rotation speed sensor 201 that detects the rotation speed Ne of the crankshaft 21 (engine 1) is provided. In the vicinity of the main shaft 22, a main shaft rotation number sensor 202 that detects the rotation number (input shaft rotation number of the automatic transmission 2) Ni of the main shaft 22 is provided. In the vicinity of the countershaft 23, a countershaft rotational speed sensor 203 for detecting the rotational speed of the countershaft 23 (the output shaft rotational speed of the automatic transmission 2) No is provided. The rotation speed data detected by each of the rotation speed sensors 201 to 203 is output to the CVT-ECU 5. The rotation speed data detected by the crankshaft rotation speed sensor 201 is also output to the FI-ECU 4.

Further, a vehicle speed sensor 204 for detecting the vehicle speed Nv of the vehicle is provided at a predetermined position of the vehicle. Vehicle speed data detected by the vehicle speed sensor 204 is output to the CVT-ECU 5. The vehicle speed Nv may be calculated from the rotational speed Ni of the main shaft 22 or the rotational speed No of the countershaft 23 without providing the vehicle speed sensor 204 that exclusively detects the vehicle speed Nv. For example, the vehicle speed Nv can be detected (calculated) based on a relational expression such as “Nv = Ni × speed ratio × tire circumference” or “Nv = No × tire circumference”. Further, an acceleration sensor 209 for detecting the acceleration Na of the vehicle and an inclination sensor 210 for detecting the road surface inclination Nd are provided. The acceleration data detected by the acceleration sensor 209 and the road surface inclination data detected by the inclination sensor 210 are output to the CVT-ECU 5.

In the vicinity of the engine 1, a throttle opening sensor 206 for detecting the throttle opening TH is provided. The throttle opening data detected by the throttle opening sensor 206 is output to the FI-ECU 4. Although not shown, a cooling water temperature sensor for detecting the cooling water temperature of the engine 1, an intake air temperature sensor for detecting the temperature of the air supplied to the engine 1 (intake air temperature), and a flow rate for detecting the air flow rate. Sensors and the like are also provided.

In the vicinity of the accelerator pedal 8, an accelerator pedal opening sensor 207 for detecting the accelerator pedal opening APAT is provided. The accelerator pedal opening degree data detected by the accelerator pedal opening degree sensor 207 is output to the FI-ECU 4.

The FI-ECU 4 controls the output of the engine 1, that is, the rotational speed Ne of the engine 1, based on the detection data input from the

sensors

201, 206, and 207 and various data input from the CVT-ECU 5. Further, the CVT-ECU 5 controls the hydraulic pressure supplied from the hydraulic control device 6 to the CVT 10 based on the detection data input from the sensors 201 to 204 and various data input from the FI-ECU 4, thereby changing the gear ratio. Control. Further, the CVT-ECU 5 increases the lockup control amount via the hydraulic control device 6 in a predetermined operation region, and engages the lockup clutch 35.

Next, the configuration (function) of the CVT-ECU 5 will be described. FIG. 2 is a functional block diagram of the CVT-ECU 5. The CVT-ECU 5 according to the present embodiment includes a memory 51 that stores a shift characteristic map 51a and the like, which will be described later, road surface gradient calculating means 52 for calculating the gradient of the road surface on which the vehicle is traveling, and a marginal driving force of the vehicle. A margin driving force calculating means 54 for calculating, a shift control means 53 for controlling the gear ratio of the CVT 10, and a lockup control means 55 for controlling engagement / disengagement of the lockup clutch 35. Prepare.

The memory 51 shows the transmission characteristics (transmission ratio distribution) of the CVT 10 on a two-dimensional map of the vehicle speed Nv detected by the vehicle speed sensor 204 and the accelerator pedal opening APAT detected by the accelerator pedal opening sensor 207. The shift characteristic map 51a and the LC map 51b showing the distribution of the engagement region and the non-engagement region of the lockup clutch 35 on the two-dimensional map are stored.

The road surface gradient calculating means 52 calculates the gradient of the road surface on which the vehicle is traveling. Specifically, in the memory 51, the accelerator pedal opening APAT detected by the accelerator pedal opening sensor 207 (or the throttle opening TH detected by the throttle opening sensor 206) and the vehicle speed sensor 204 are detected. The expected acceleration expected for the vehicle when traveling on a flat road according to the vehicle speed Nv is stored (set), and the road surface gradient calculating means 52 is the actual acceleration actually generated in the vehicle from the vehicle speed Nv. And the slope of the road surface is calculated by comparing the predicted acceleration with the actual acceleration. The road surface gradient thus calculated is output to the lockup control means 55 and the shift control means 53. In addition to the above, the slope of the road surface may be calculated by performing calculations based on the road surface inclination Nd detected by the inclination sensor 210 and the vehicle acceleration Na detected by the acceleration sensor 209. Or you may make it calculate the gradient of a road surface by calculating based only on the inclination Nd of the road surface detected with the inclination sensor 210. FIG.

The margin driving force calculating means 54 calculates the margin driving force of the vehicle. The marginal driving force of the vehicle is
(Extra drive force) = (output drive force)-(required drive force) or
(Extra drive force) = (output drive force) / (required drive force)
It is represented by And
(Output driving force) = (input torque of the automatic transmission 2) × (gear ratio (final gear ratio, etc.)) × (pulley ratio of the CVT 10) × (T / M efficiency of the automatic transmission 2) / (tire dynamic radius)
And
(Necessary driving force) = (Rolling resistance) + (Air resistance) + (Acceleration resistance) + (Gradient resistance)
It is.

The speed change control means 53 controls the speed ratio by the CVT 10 according to the speed change characteristic map 51a stored in the memory 51 based on the detection data input from the sensors 201 to 204 and the various data input from the FI-ECU 4. .

Further, the lockup control means 55 is stored in the memory 51 based on the road surface gradient S input from the road surface gradient calculation means 52 and the vehicle margin driving force M calculated by the margin driving force calculation means 54. Switching of engagement / disengagement of the lockup clutch 35 is controlled according to the LC map 51b. Here, the engagement / disengagement switching control (hereinafter simply referred to as “engagement control”) of the lockup clutch 35 by the lockup control means 55 will be described in detail.

FIG. 3 is a diagram showing a control flow (main flow) in the engagement control of the lockup clutch 35. In the control flow of FIG. 3, the lockup clutch 35 is abbreviated as “LC”, and the engagement / disengagement of the lockup clutch 35 is described as ON / OFF. The engagement control of the lockup clutch 35 here is performed when the vehicle is traveling. First, it is determined whether or not the vehicle is traveling with the lockup clutch 35 engaged (ON). (Step ST1-1). As a result, if the vehicle is traveling with the lock-up clutch 35 engaged (YES), the uphill LC-OFF flag is determined (step ST1-2). On the other hand, when the vehicle is traveling with the lockup clutch 35 being disengaged in step ST1-1 (NO), the climbing LC-OFF flag is also determined (step ST1-3).

FIG. 4 is a diagram showing a control flow (subroutine) of the determination procedure for the climbing LC-OFF flag. In the determination of the climbing LC-OFF flag, it is first determined whether or not the climbing LC-OFF flag is 1 in the determination history of the climbing LC-OFF flag in the processing up to the previous time (step ST2-1). As a result, if the climbing LC-OFF flag = 0 (NO), it is subsequently determined whether or not the margin driving force M calculated by the margin driving force calculation means 54 is equal to or greater than a predetermined value M0 (step ST2- 2). As a result, when the marginal driving force M is less than the predetermined value M0 (no marginal driving force) (NO), the road surface gradient S calculated by the road surface gradient calculating means 52 continues to be the first gradient S. It is determined whether or not the value is equal to or greater than a predetermined value S1 (10 ° as an example) (step ST2-3). As a result, if the gradient S is equal to or higher than the first predetermined value S1 (high gradient) (YES), it is subsequently determined whether or not the vehicle speed V is equal to or higher than a predetermined value V0 (20 km / h as an example) ( Step ST2-4). As a result, if the vehicle speed V is less than the predetermined value V0 (low vehicle speed) (NO), the uphill LC-OFF flag ← 1 is set (step ST2-5).

On the other hand, if the climbing slope LC-OFF flag = 1 in the previous step ST 2-1 (YES), the road surface gradient S calculated by the road surface gradient calculation means 52 continues to be the first slope S described above. It is determined whether or not it is equal to or greater than a second predetermined value S2 (8 ° as an example) that is smaller than the predetermined value S1 (step ST2-6). As a result, when the road surface slope S is less than the second predetermined value S2 (low slope) (NO), the climbing LC-OFF flag ← 0 is set (step ST2-7), and the slope S is the second predetermined value. If it is S2 or more (high gradient) (YES), the uphill LC-OFF flag is not updated and the previous value is maintained (step ST2-8).

If the margin driving force M is equal to or greater than the predetermined value M0 (with margin driving force) in the previous step ST2-2 (YES), the climbing LC-OFF flag ← 0 is set (step ST2-7). Also, in the previous step ST2-3, also when the slope S of the road surface on which the vehicle is traveling is less than the first predetermined value S1 (low slope) (NO), the climbing LC-OFF flag ← 0 is set ( Step ST2-7). Further, when the vehicle speed V is equal to or higher than the predetermined value V0 (high vehicle speed) in the previous step ST2-4 (YES), the climbing LC-OFF flag ← 0 is set (step ST2-7).

That is, in the determination of the uphill LC-OFF flag, the vehicle has no marginal driving force (NO in step ST2-2), and the slope of the road surface on which the vehicle is traveling is equal to or greater than a predetermined value (first predetermined value). If the slope is high (YES in step ST2-3) and the vehicle speed is less than a predetermined value (low vehicle speed) (NO in step ST2-4), the climbing LC-OFF flag ← 1 is set (step ST2- 5). On the other hand, the vehicle has a marginal driving force (YES in step ST2-2), or the gradient of the road surface on which the vehicle is traveling is a low gradient less than a predetermined value (first predetermined value) (step ST2- If the vehicle speed is higher than the predetermined value (YES in step ST2-4), the climbing LC-OFF flag ← 0 is set (step ST2-7).

Returning to the main flow of FIG. 3, when the lockup clutch 35 is running in the engaged state in step ST1-1 (YES), the climbing LC-OFF flag is determined in step ST1-2, and then the climbing is performed. It is determined whether or not the LC-OFF flag = 1 (step ST1-4). As a result, if the climbing LC-OFF flag = 1 (YES), the lock-up clutch 35 is disengaged (disengaged) (step ST1-5). On the other hand, if the climbing LC-OFF flag = 0 in step ST1-4 (NO), the engagement of the lockup clutch 35 is permitted (step ST1-6).

On the other hand, when the lockup clutch 35 is traveling in the non-engaged state in step ST1-1 (NO), the climbing LC-OFF flag is determined in step ST1-3, and then the climbing LC-OFF flag is determined. = 1 or not (step ST1-7). As a result, if the climbing LC-OFF flag = 1 (YES), the engagement of the lockup clutch 35 is prohibited (step ST1-8). On the other hand, if the climbing LC-OFF flag = 0 in step ST1-7 (NO), the engagement of the lockup clutch 35 is permitted (step ST1-6).

That is, when the vehicle is traveling with the lockup clutch 35 engaged (YES in step ST1-1) and the climbing LC-OFF flag = 1 (YES in step ST1-4), the lockup clutch 35 is not engaged. (Step ST1-5) When the climbing LC-OFF flag = 0 (NO in Step ST1-4), the engagement of the lockup clutch 35 is permitted (Step ST1-6). Further, when the uphill LC-OFF flag = 1 is set while the lockup clutch 35 is traveling in the non-engaged state (NO in step ST1-1) (YES in step ST1-7), the lockup clutch 35 is engaged. Is prohibited (step ST1-8), and when the climbing LC-OFF flag = 0 (NO in step ST1-7), the engagement of the lockup clutch 35 is permitted (step ST1-6).

When the lock-up clutch is engaged while the vehicle is traveling on a road surface with a large slope (uphill road), there is a problem that the running performance of the uphill road deteriorates due to the vehicle speed stagnating or decreasing. Such a problem becomes particularly remarkable in a small vehicle having a small driving force. Therefore, in the lockup control means 55 provided in the control device for the automatic transmission according to the present embodiment, the road surface slope calculated by the road surface slope calculation means 52 while the vehicle is running without engaging the lockup clutch 35. When the gradient S becomes equal to or higher than the first predetermined value S1, control for prohibiting the engagement of the lockup clutch 35 is performed. As a result, when the vehicle is traveling on an uphill road having a gradient equal to or greater than the first predetermined value S1, it is possible to effectively prevent the vehicle speed from stagnating or decreasing. Merchantability). Further, since the engagement amount control (slip control) of the lockup clutch 35 is not performed while the engagement of the lockup clutch 35 is prohibited, the heat generation amount of the lockup clutch 35 can be kept low. Therefore, since the friction material of the lockup clutch 35 can be protected, the durability of the lockup clutch 35 can be improved.

Further, the lockup control means 55 provided in the automatic transmission control device of the present embodiment has the road surface gradient calculated by the road surface gradient calculation means 52 in a state where the engagement of the lockup clutch 35 is prohibited. When the value is equal to or smaller than the second predetermined value S2, which is smaller than the predetermined value S1, the control for canceling the prohibition of the lockup clutch 35 is performed.

According to this configuration, since the prohibition of the engagement of the lockup clutch 35 is released after the gradient of the road surface on which the vehicle travels becomes smaller than the second predetermined value S2, the traveling performance of the uphill road is improved and the fuel consumption is improved. It can contribute to both improvement. Further, by providing a difference between the gradient condition (first predetermined value S1) for prohibiting the engagement of the lockup clutch 35 and the gradient condition (second predetermined value S2) for canceling the prohibition, the lockup clutch 35 is provided. It is possible to prevent a hunting phenomenon in which prohibition and release of engagement are frequently repeated.

Also, when the vehicle enters the uphill road with the lockup clutch engaged, if the lockup clutch is engaged as it is, the running speed of the uphill road deteriorates because the vehicle speed is stagnated or lowered. This point is particularly remarkable in a small vehicle having a small driving force. Accordingly, the lockup control means 55 provided in the control device for the automatic transmission according to the present embodiment includes the road surface gradient S calculated by the road surface gradient calculation means 52 while the vehicle is running with the lockup clutch 35 engaged. When the value becomes equal to or greater than the first predetermined value S1, control for releasing the engagement of the lockup clutch 35 (disengagement) is performed. As a result, when the vehicle enters an uphill road having a gradient equal to or greater than the first predetermined value S1, it is possible to effectively prevent the vehicle speed from stagnating or decreasing, so that the running performance of the uphill road can be improved. Further, when the road surface gradient S is equal to or greater than the first predetermined value S1, the first predetermined value S1 is set to an appropriate value by performing the control for releasing the engagement of the lockup clutch 35. Thus, the lockup clutch 35 can be disengaged before the vehicle speed decreases. Therefore, the fluctuation of the vehicle body due to the disengagement of the lockup clutch 35 can be suppressed, and shocks such as vibration and noise can be prevented from being transmitted to the vehicle body and the occupant.

Further, in this case, the lockup control means 55 is in a state where the lockup clutch 35 is disengaged (non-engaged), and the road surface gradient calculated by the road surface gradient calculation means 52 is the first. When it becomes equal to or smaller than a second predetermined value S2 smaller than the predetermined value S1, control for engaging the lockup clutch 35 is performed.

According to this configuration, both the improvement of the driving performance on the uphill road and the improvement of the fuel consumption can be achieved by engaging the lock-up clutch 35 after the slope of the road surface on which the vehicle travels becomes smaller than the second predetermined value S2. Can contribute. Further, by providing a difference between the gradient condition for disengaging the lockup clutch 35 (first predetermined value S1) and the gradient condition for engaging (second predetermined value S2), the lockup clutch 35 It is possible to prevent a hunting phenomenon in which engagement and release are frequently repeated.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the technical idea described in the claims and the specification and drawings. Is possible. For example, in the above-described embodiment, the automatic transmission 2 includes the CVT 10 as a transmission mechanism for shifting the rotation transmitted from the main shaft 22 to the counter shaft 23. Although omitted, the automatic transmission has a stepped transmission having a plurality of gear trains (gear trains) and a plurality of clutches (friction engagement elements) provided corresponding to the respective shift stages as the above-described transmission mechanism. A mechanism may be provided.

In the above embodiment, the present invention has been described based on a vehicle including the engine 1 as a drive source. However, the drive source of the vehicle equipped with the automatic transmission control device according to the present invention is a drive source other than the engine. There may be. For example, the present invention can be applied to a so-called hybrid vehicle that includes not only the engine 1 but also a motor-generator as a drive source, as long as it has a torque converter including a lock-up clutch. .

Further, in the above-described embodiment, the case where the electronic control unit (ECU) that controls the engine 1 and the automatic transmission 2 is configured by two of the FI-ECU 4 and the CVT-ECU 5 has been described. However, the present invention is not limited to such a configuration, and the two FI-ECUs 4 and the CVT-ECU 5 may be integrated into one ECU.

Claims

A control device for an automatic transmission having a torque converter having a lock-up clutch that switches engagement / disengagement between an input element coupled to a drive source and an output element coupled to an automatic transmission,
Lockup control means for controlling switching of engagement / disengagement of the lockup clutch;
Road surface gradient calculating means for calculating the gradient of the road surface on which the vehicle is traveling,
The lock-up control means includes
When the road surface gradient calculated by the road surface gradient calculating means becomes equal to or higher than a first predetermined value while the vehicle is traveling without engaging the lock-up clutch, A control device for an automatic transmission, which performs control for prohibiting engagement.
The lock-up control means includes
When the road surface gradient calculated by the road surface gradient calculating means is not more than a second predetermined value smaller than the first predetermined value in a state where the engagement of the lockup clutch is prohibited, 2. The control device for an automatic transmission according to claim 1, wherein control for canceling prohibition of engagement of the lock-up clutch is performed.
A control device for an automatic transmission having a torque converter having a lock-up clutch that switches engagement / disengagement between an input element coupled to a drive source and an output element coupled to an automatic transmission,
Lockup control means for controlling switching of engagement / disengagement of the lockup clutch;
Road surface gradient calculating means for calculating the gradient of the road surface on which the vehicle is traveling,
The lock-up control means includes
While the vehicle is running with the lockup clutch engaged, if the road surface gradient calculated by the road surface gradient calculation means exceeds a first predetermined value, the lockup clutch is engaged. A control device for an automatic transmission, characterized in that control for canceling is performed.
The lock-up control means includes
When the road surface gradient calculated by the road surface gradient calculating means becomes equal to or lower than a second predetermined value smaller than the first predetermined value after the lockup clutch is disengaged, the lockup is performed. 4. The control device for an automatic transmission according to claim 3, wherein control for engaging the clutch is performed.