JP2003130207A - Control device for lock-up clutch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the compatibility of the state of a vehicle and the state of a lock-up clutch. SOLUTION: This control device for the lock-up clutch has a function for controlling an engagement state of the lock-up clutch and is capable of selecting a first control mode for controlling the lock-up clutch by a first condition. The control device has a condition determination means for further determining a third condition when a second condition different from the first condition is established, a first control mode selection means (step S1 and S3) for determining whether or not a second control mode for controlling the engagement state of the lock-up clutch by the second condition is selected based on the third condition, and a second control mode selection means (step S2, S5, S6, S7, S8 and S9) for further determining whether or not the second control mode is selected based on a function of an actuator for controlling the lock-up clutch when the second control mode can be selected by the first control mode determination means (step S1 and S3).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for controlling a lockup clutch arranged in parallel with a hydraulic power transmission device.

[0002]

2. Description of the Related Art The power output from a driving force source is configured to be transmitted to a second rotary member via a first rotary member, and the first rotary member and the second rotary member are rotated. A vehicle is known in which a fluid transmission and a lockup clutch are arranged in parallel between the member and the member. In such a vehicle, if the lockup clutch is released and power is transmitted between the first rotating member and the second rotating member by the kinetic energy of the fluid, the torque fluctuation of the driving force source can be achieved. However, it is possible to prevent the torque fluctuation of the driving force source from being transmitted to the second rotating member by being absorbed or alleviated by the slip between the first rotating member and the second rotating member. On the other hand, when the lockup clutch is engaged, frictional force transmits power between the first rotating member and the second rotating member, so that the first rotating member moves to the second rotating member. The loss of power transmitted to the rotating member can be suppressed.

An example of a device for controlling the lock-up clutch arranged in parallel with the fluid transmission device as described above is described in Japanese Patent Laid-Open No. 5-332431.
In this publication, the torque output from the engine is configured to be transmitted to the drive wheels via a fluid coupling (fluid transmission device), a forward / reverse switching mechanism, a continuously variable transmission, and a differential device. There is. A lockup clutch is provided in parallel with the fluid coupling. Further, a control unit is provided for detecting the throttle opening and the vehicle speed and controlling the lockup clutch based on the detection result.

When the throttle opening is above a predetermined value, the engine speed is above a predetermined value, and the vehicle speed is below a predetermined value, for example, when the vehicle starts, the lockup clutch is engaged for a predetermined time. Control is performed. By performing such control, the increase of the engine speed is temporarily stopped, and the torque amount consumed by the inertia of the engine can be made almost "zero", and therefore, the torque is transmitted to the drive wheels. It is said that the driving force is substantially increased and the starting performance is improved.

[0005]

However, in the above publication, the lock-up clutch is engaged when the vehicle is started, so that there is a problem that the state of the lock-up clutch and the state of the vehicle do not match. It was

The present invention has been made in view of the above circumstances, and provides a lock-up clutch control device capable of further improving the compatibility between the vehicle state and the lock-up clutch control state. It is an object.

[0007]

In order to achieve the above-mentioned object, the invention of claim 1 is a lock-up clutch provided in a power transmission path of a vehicle and arranged in parallel with a fluid transmission. In the lock-up clutch control device having a function of controlling the engagement state of the lock-up clutch and capable of selecting the first control mode for controlling the lock-up clutch according to the first condition, the first condition is First determining means for further determining a third condition different from the first condition and the second condition when another second condition is satisfied; and the lockup according to the second condition. Second judgment means for judging whether or not to select the second control mode for controlling the engagement state of the clutch based on whether or not the third condition is satisfied, and the second judgment means for judging the second condition.
Whether the second control mode is selected based on a physical quantity related to the function of the actuator that controls the lock-up clutch, when the control mode can be selected.
It is characterized in that it further comprises a third judging means for judging.

According to the first aspect of the invention, when the second control mode can be selected, whether or not the second control mode is selected based on the physical quantity related to the function of the actuator for controlling the lockup clutch. Is further judged. Therefore, problems that occur when controlling the engagement state of the lockup clutch based on the second control mode, for example, frequent changes in driving force and sudden changes in driving force are avoided in advance.

According to a second aspect of the present invention, there is provided a function of controlling an engagement state of a lockup clutch provided in a power transmission path of a vehicle and arranged in parallel with a fluid transmission device. In a lock-up clutch control device capable of selecting a first control mode for controlling the lock-up clutch, the first condition is satisfied when a second condition different from the first condition is satisfied. And the second
The first determination means for further determining a third condition different from the above condition and whether or not to select the second control mode for controlling the engagement state of the lock-up clutch according to the second condition. , Second judging means for judging based on whether or not the third condition is satisfied, and the second judging means for judging the second condition.
When it is possible to select one of the control modes, a fourth judgment means is further provided for judging whether or not to select the second control mode based on the prediction result of the rotation speed of the driving force source. It is characterized by being present.

According to the second aspect of the present invention, when the second control mode can be selected, a change in the rotational speed of the driving force source when the lockup clutch is controlled by the second control mode is predicted. Based on the prediction result, it is further determined whether or not to select the second control mode. Therefore, a problem in controlling the lockup clutch based on the second control mode, that is, "the rotation speed of the driving force source becomes a rotation speed other than the desired rotation speed" is avoided in advance. .

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the structure of a vehicle to which the present invention can be applied will be described with reference to FIG. In the vehicle 1 shown in FIG. 3, a torque converter 4 as a fluid transmission device and a transmission 5 are provided in a power transmission path between the driving force source 2 and the wheels 3. First, as the driving force source 2, at least one of an engine and an electric motor can be used. An engine is a power unit of a type that burns fuel to output power. As this engine, an internal combustion engine, for example, a gasoline engine,
An LPG engine, a diesel engine, a methanol engine, a hydrogen engine, etc. can be used. Less than,
A case where an engine is used as the driving force source 2 will be described. Therefore, instead of the driving force source 2, it is referred to as "engine 2" for convenience.

The torque converter 4 transmits power between the rotary member 6 connected to the engine 2 side and the rotary member 7 connected to the transmission 5 side by the kinetic energy of the fluid. . This torque converter 4 is
A pump impeller 8 connected to the rotating member 6 side, a turbine runner 9 connected to the rotating member 7 side, and a stator 10
And have. Also, in parallel with the torque converter 4,
A lockup clutch 11 is provided. The lockup clutch 11 transmits power between the rotating member 6 and the rotating member 7 by frictional force. The lockup clutch 11 changes the capacity of the torque transmitted between the rotary member 6 and the rotary member 7 by controlling the engagement pressure thereof.

As the transmission 5, a transmission having at least one of a manual shift function and an automatic shift function can be used. A transmission having a manual transmission function means the ratio of the rotation speed of the rotary member 7 connected to the input side of the transmission 5 to the rotation speed of the rotary member 12 on the output side of the transmission 5, that is, the gear ratio. , Means a transmission that can be changed based on the operating state of the gear ratio selection device by the driver. On the other hand, a transmission having an automatic transmission function means a transmission that can automatically control the transmission gear ratio based on conditions other than the operating state of the transmission gear ratio selection device. .

As the transmission 5, either a continuously variable transmission or a stepped transmission may be used. The continuously variable transmission means a transmission that can control the speed ratio continuously or continuously. Examples of the continuously variable transmission include a belt type continuously variable transmission and a toroidal type continuously variable transmission. On the other hand, the stepped transmission means a transmission capable of controlling the speed change ratio discontinuously or stepwise. As a stepped transmission, a selection gear type transmission,
Examples include planetary gear type transmissions.

A hydraulic control device 13 for controlling the lockup clutch 11 and the transmission 5 is provided.
The hydraulic control device 13 has a hydraulic circuit (not shown) to which the oil discharged from the oil pump 28 is supplied, an electromagnetic valve (not shown) arranged in the hydraulic circuit, and the like. The hydraulic control device 13 controls the engagement state of the lockup clutch 11, the gear ratio of the transmission 5, and the like. The engagement state of the lockup clutch 11 is specifically controlled according to the oil pressure of the oil supplied to the lockup clutch 11.

The oil pump 28 is connected to the rotary member 7, and the power of the engine 1 is transmitted to the rotary member 7 via the torque converter 4 to drive the oil pump 28. That is, the oil pump 2
The oil discharge amount of No. 8 changes depending on the engine speed. The hydraulic pressure of the oil discharged from the oil pump 28 is adjusted to a predetermined line pressure by the solenoid valve, and the line pressure is adjusted by another solenoid valve to act on the lockup clutch 11 to lock up. The engagement pressure of the clutch 11 is controlled.

Further, an electronic control unit 14 is provided as a controller for controlling the engine 2, the transmission 5, and the lockup clutch 11. The electronic control unit 14 is composed of a central processing unit (CPU), a storage device (ROM, RAM), and a microcomputer mainly including an input / output interface.
The electronic control unit 14 includes a signal from the accelerator opening sensor 15, a signal from an input rotation speed sensor 16 that detects the rotation speed of the rotating member 7, and a signal from an output rotation speed sensor 17 that detects the rotation speed of the rotating member 12. Signal of brake switch 18, signal of throttle opening sensor 19, signal of weight detection sensor 20, signal of towing detection sensor 21, signal of uphill road detection sensor 22, signal of oil temperature sensor 23, lockup clutch temperature detection sensor 24 Signal of the engine speed sensor 25, signal of the traffic jam sensor 26, signal of the shift position sensor 27, signal of the acceleration sensor 29,
A signal from the idle switch 30 or the like is input.

Based on the signal from the output speed sensor 17,
The moving speed (vehicle speed) of the vehicle 1 is determined, and the engine load is determined based on the vehicle speed and a signal from the accelerator opening sensor 15 (or the throttle opening sensor 19). The weight detection sensor 20 detects the total weight of the vehicle 1, the weight of an occupant, the weight of loaded luggage, and the like. The oil temperature sensor 23 detects the temperature of the oil supplied to the hydraulic circuit of the hydraulic control device 13. Congestion detection sensor 2
Reference numeral 6 is for detecting a traffic jam situation on a road on which the vehicle 1 is traveling. The towing detection sensor 21 detects whether or not the vehicle 1 is in a state of traveling by towing another vehicle. The lockup clutch temperature detection sensor 24 is
The temperature of the lockup clutch 11 is detected.

The shift position sensor 27 is used for the transmission 5
It detects the selected state of the shift position that controls the. The shift position is a forward position where the torque for moving the vehicle 1 forward can be output from the transmission 5, and a torque for moving the vehicle 1 backward (backward) is the transmission 5.
And a non-driving position where the torque for driving the vehicle 1 cannot be output from the transmission 5. That is, when the shift position is the forward position or the reverse position, the vehicle 1 may start.

The electronic control unit 14 stores engine control data for controlling the engine output, lockup clutch control data for controlling the lockup clutch 11, shift control data for controlling the transmission 5, and the like. Has been done.

Then, based on the data stored in the electronic control unit 14 and the signal input to the electronic control unit 14, the output of the engine 2, the engagement state of the lockup clutch 11, the gear ratio of the transmission 5, etc. Is controlled.

In this embodiment, the "engagement state of the lockup clutch 11" includes engagement / release / slip of the lockup clutch 11. That is,
"Controlling the engagement state of the lockup clutch 11" means
This means controlling the engagement pressure of the lockup clutch 11 or the torque capacity of the lockup clutch 11.

Next, the control of the engagement state of the lockup clutch 11 will be specifically described. First, when the lockup clutch 11 is released, power is transmitted between the rotary member 6 and the rotary member 7 by the kinetic energy of the fluid. When the lockup clutch 11 is released, a difference in rotational speed between the rotating member 6 and the rotating member 7 is allowed to occur. When the lockup clutch 11 is released, the rotary member 6 and the rotary member 7 are released.
In a state in which the speed ratio of the rotation speed and the rotation speed is within a predetermined range (so-called torque converter range),
The torque transmitted between and is amplified by the function of the stator 10.

On the other hand, the lockup clutch 11
Is engaged (when the engagement pressure of the lockup clutch 11 is equal to or higher than a predetermined value), the frictional force (engagement force) of the lockup clutch 11 is applied between the pump impeller 8 and the turbine runner 9. Power is transmitted. When the lockup clutch 11 is engaged, the rotating member 6 and the rotating member 7 rotate integrally.

On the other hand, the slip of the lock-up clutch 11 is a state in which the engagement pressure of the lock-up clutch 11 is controlled to be higher than the released state and lower than the engaged state. That is, although the friction members forming the lock-up clutch 11 are in contact with each other, a predetermined rotation speed difference is generated between the rotating member 6 and the rotating member 7. Therefore, the frictional force of the lockup clutch 11,
Power is transmitted between the rotating member 6 and the rotating member 7 by both the kinetic energy of the fluid and the kinetic energy of the fluid.

In this embodiment, when controlling the engagement state of the lockup clutch 11, it is possible to determine whether or not to select the second control mode. Here, in “selecting the second control mode”, the case where the second control mode is newly selected and the second control mode has already been selected, the second control mode is continued. Cases and are included. In addition, “no” includes the case of stopping the already selected second control mode or the case of prohibiting the new selection of the second control mode. In addition,
Even if the second control mode is formally selected, the lockup clutch is engaged / released / released based on the control mode.
Unless the slip is executed, the second control mode is not substantially selected.

[0027]

Next, a method of selecting a control mode for controlling the engagement state of the lockup clutch 11 will be specifically described. FIG. 2 shows a map which is an example of lockup clutch control data. In the map shown in FIG. 2, the engagement state of the lockup clutch 11 is shown based on the correspondence between the vehicle speed and the throttle opening (or accelerator opening). In FIG. 2, engagement and disengagement of the lock-up clutch 11 are shown for convenience, and slip is omitted.

FIG. 2 shows the control mode for normal traveling (first control mode) and the control mode for start / re-acceleration (second control mode) in a combined manner. First, the first control mode has an engagement area B1 and a release area B2.
The engagement area B1 and the release area B2 are separated by a solid line A1 and a broken line A2. The solid line A1 is set to a higher vehicle speed side than the broken line A2. The solid line A1 is a reference used when the released lockup clutch 11 is engaged. For example, when the vehicle speed and the throttle opening are on the left side of the solid line A1, the lockup clutch 11 is released. From this state, when the vehicle speed and the throttle opening change to the right of the solid line A1, the lockup clutch 11 is engaged (turned on).

Next, the broken line A2 is used to release the engaged lock-up clutch 11.
The engaged lock-up clutch 11 is not released only when the vehicle speed and the accelerator opening exceed the solid line A1 from the state in the engagement region B1. That is, when the vehicle speed and the throttle opening change to the area on the left side of the broken line A2, the engaged lockup clutch 11 is released (turned off). The solid line A1
The area on the right side of the vehicle has a higher vehicle speed than the area on the left side of the solid line A1. The region on the right side of the broken line A2 has a higher vehicle speed than the region on the left side of the broken line A2.

The reason why the predetermined hysteresis is provided between the solid line A1 and the broken line A2 is that the lockup clutch 11 is engaged when the vehicle speed and the throttle opening change near the solid line A1. Alternating with liberation, and
This is to prevent the phenomenon of frequent switching, so-called hunting. The solid line A1 shown in FIG.
The throttle opening and the vehicle speed divided by the broken line A2 are the first condition. Then, the engagement area B1 and the release area B2 set corresponding to the first condition.
Is the first control mode.

On the other hand, in the second control mode, the lockup clutch 11 is engaged at a speed lower than the vehicle speed corresponding to the engagement area B1 in the throttle opening area below the alternate long and short dash line C1 corresponding to the predetermined throttle opening. It has an engagement area D1. The engagement area D1 is for engaging the lock-up clutch 11 when the vehicle 1 starts or when the vehicle speed is decelerated from the state in the engagement area B1 and then re-accelerated. That is, the vehicle speed is in the engagement region B.
Even if the vehicle speed is reduced from the state of 1 to the left side (low speed side) of the broken line A2 and the lockup clutch 11 is once released, when the vehicle speed is accelerated again, the vehicle speed is in the engagement region B1. The lockup clutch 11 is engaged even if the vehicle speed is lower than the corresponding speed.

Further, a two-dot chain line C2 serving as a reference when releasing the engaged lock-up clutch 11 is set corresponding to the engagement area D1. Two-dot chain line C2
Is set to a higher opening side than the one-dot chain line C1. Therefore, the lockup clutch 1 corresponds to the engagement area D1.
When 1 is engaged, the lockup clutch 11 is disengaged when the throttle opening reaches a high opening until it exceeds the chain double-dashed line C2. As described above, the reason why the hysteresis is set between the one-dot chain line C1 and the two-dot chain line C2 is that the hunting of the lock-up clutch 11 is prevented when the vehicle speed and the throttle opening slightly change near the one-dot chain line C1. This is because

It should be noted that the alternate long and short dash line C1 shown in FIG.
And the vehicle speed and the throttle opening that are divided by the chain double-dashed line C2 are the second condition, and "based on the engagement region D1 and the release region B2 set corresponding to the second condition,
Controlling the engagement state of the lockup clutch 11 "
Is the second control mode. That is, although the quality of the parameters themselves (vehicle speed and throttle opening) is the same between the first condition and the second condition described above, their degrees are different. Even if the vehicle speed and the throttle opening are in any of the regions shown in FIG. 2, engagement / release of the lockup clutch corresponding to the region is performed unless the control mode corresponding to the region is selected. Absent.

In the vehicle 1 shown in FIG. 3, the first control mode is basically selected, and the lockup clutch 11 is controlled based on this first control mode.
Next, in the first control mode, the lockup clutch 11
A method of selecting the second control mode in which the lock-up clutch 11 can be engaged in the vehicle speed range where the vehicle speed is released and the vehicle speed below the solid line A1 will be described with reference to the flowchart of FIG. First, in step S1, it is determined "whether or not the first nonconformance condition is satisfied". The first non-compliance condition is a physical quantity related to the load of the engine 1, a physical quantity related to responsiveness when controlling the engagement state of the lockup clutch 11, and a physical quantity related to durability of the lockup clutch 11. It is judged based on.

As the physical quantity related to the engine load,
For example, the load detection amount detected by the weight detection sensor 20 is less than or equal to a predetermined amount, and the towing detection sensor 21
The pulling condition detected by is less than a predetermined load. At least one of these matters
That is, the engine load is high. Therefore, it is desirable to make the vehicle speed range in which the lockup clutch 11 is engaged as narrow as possible so that the torque converter 4 can exert the torque amplification function.

As the physical quantity related to the responsiveness when controlling the engagement state of the lockup clutch 11,
For example, the temperature of the oil detected by the oil temperature sensor 23 is equal to or higher than the first predetermined temperature and equal to or lower than the second predetermined temperature which is higher than the second predetermined temperature. . When the temperature of the oil is equal to or lower than the first predetermined temperature, the viscosity of the oil increases, so that the control responsiveness of the lockup clutch 11 may decrease.
Further, when the temperature of the oil is higher than the second predetermined temperature, the viscosity of the oil decreases, so that the oil leaks from the gap of the hydraulic circuit and the lockup clutch 11
The control response of may decrease. Therefore, if at least one of these things is happening:
It is desirable to narrow the vehicle speed range in which the lockup clutch 11 is engaged as much as possible.

Further, as the physical quantity related to the durability of the lockup clutch 11, the lockup clutch 1
The temperature of 1 is below a predetermined temperature and the road is not congested. Lockup clutch 11
If the temperature is higher than the predetermined temperature, the durability of the lockup clutch 11 may decrease due to frictional heat. Further, when the road is congested, the vehicle speed may change frequently and the lock-up clutch 11 may be repeatedly engaged and released, and the lock-up clutch 11 may wear and the durability may be reduced. Therefore, when at least one of such matters is occurring, it is desirable to narrow the vehicle speed range in which the lockup clutch 11 is engaged as much as possible.

Under these circumstances, when at least one of the above items occurs, a positive determination is made in step S1 and it is prohibited to select the second control mode. (Step S2), the process returns.
In this way, it is possible to suppress the deterioration of the engagement response of the lockup clutch 11 and the deterioration of the durability of the lockup clutch 11.

On the other hand, if none of the above-mentioned matters has occurred, a negative determination is made in step S1 and the process proceeds to step S3. In step S3, it is determined whether the vehicle 1 travels on an uphill road. When the vehicle 1 travels on an uphill road (when the second nonconformance condition is satisfied), the engine load is high. Therefore,
Even if a positive determination is made in step S3, step S3
The process proceeds to step S2 for the same reason as described in 1. In this way, the torque amplifying function of the torque converter 4 is ensured, the insufficient driving force of the vehicle 1 can be avoided, and the power performance is improved. Further, the engagement pressure of the lock-up clutch 11 is increased, the engine load is increased, the engine speed is decreased, and eventually the engine stall can be prevented.

On the other hand, if the determination in step S3 is negative, "whether the vehicle 1 is in a starting state from a stopped state" or "the vehicle 1 is decelerated while traveling, and then
It is determined whether or not it is in the state of reacceleration "(step S
4). That is, the determination in step S4 determines whether the vehicle speed and the throttle opening are in the engagement area D1. When a negative determination is made in step S4 (for example, when the vehicle speed and the throttle opening are in the release area B2 which is an area above the chain double-dashed line C2), the process is returned as it is.

On the other hand, if the affirmative determination is made in step S4, the vehicle speed is not higher than the predetermined speed, the idle switch 30 is off, and the vehicle speed is decreasing (decelerating). All of the above) have occurred (step S5). The positive determination in step S5 means that the vehicle 1 is traveling on an uphill road. Note that step S
The slope of the uphill road determined in 5 is lower than the slope of the uphill road determined in step S3.

Therefore, if an affirmative decision is made in step S5, the operation proceeds to step S2, and the selection of the second control mode is prohibited. If the second control mode is already selected and the control for sweeping up the engagement pressure of the lockup clutch 11 is started, the engagement pressure of the lockup clutch 11 is swept in step S2. Bring it down. That is, step S5 is a guard for determining whether or not to prohibit the second control mode from being selected before the uphill road determination corresponding to step S3 is established.

On the other hand, if the determination in step S5 is negative, the idle switch 30 is on, or the vehicle speed is "zero" and the brake switch 18 is on. Alternatively, it is determined whether or not at least one of the fact that the vehicle speed is equal to or lower than the predetermined vehicle speed and the vehicle speed is increasing (accelerating) but the acceleration is equal to or higher than the predetermined acceleration (step S
6). If a positive determination is made in step S6,
The "prohibition of selecting the second control mode" is canceled (in other words, the selection of the second control mode is permitted) (step S7), and the process returns.

On the other hand, if the determination in step S6 is negative, "the second control mode has already been selected, the engagement pressure of the lockup clutch 11 is being swept up, and It is determined whether or not the vehicle speed is equal to or lower than the predetermined vehicle speed and the acceleration is equal to or lower than the predetermined acceleration (step S8). When a positive determination is made in step S8, the control for sweeping up the engagement pressure of the lockup clutch 11 is stopped (step S9), and the process returns.
If the determination in step S8 is negative, the process directly returns.

As described above, according to this embodiment, the selection of the second control mode is prohibited when a positive determination is made in any of steps S1, S3 and S5. For this reason, when the engine speed is below the predetermined speed,
It is possible to suppress "the engagement pressure of the lockup clutch 11 is increased and the engine load is increased". Therefore,
The engine speed drops below the speed at which autonomous rotation is possible,
In addition, it is possible to prevent a phenomenon in which the engine 1 stops, that is, a so-called “engine stall”.

In the vehicle 1 shown in FIG. 3, the power of the engine 1 is transmitted to the rotating member 7 via the torque converter 4, and the power of the rotating member 7 causes the oil pump 2 to travel.
8 is configured to be driven. Therefore, when the rotation speed of the engine 1 is equal to or lower than the predetermined rotation speed, the oil pump 28 may not be able to discharge the amount of oil required to increase the engagement pressure of the lockup clutch 11.

On the other hand, when the engine speed exceeds the predetermined speed during the control for sweeping up the engagement pressure of the lockup clutch 11, the discharge amount of the oil pump 28 increases and the lockup clutch The original pressure of the hydraulic pressure supplied to 11 will suddenly increase. With such an action, the output torque of the transmission 5 suddenly changes,
You may experience a shock.

Therefore, in this embodiment, the second control is performed in the case where the affirmative determination is made in any of steps S1, S3 and S5, that is, when the engine speed is lower than the predetermined speed. It is prohibited to select a mode. Therefore, it is possible to prevent the above inconvenience from occurring.

Further, when the engagement pressure of the lockup clutch 11 is increased in a state where the engine speed is equal to or lower than the predetermined speed, the engine load increases and the engine speed decreases. When the engine speed drops, the oil pump 2
Since the discharge amount of No. 8 decreases and the amount of oil required for engaging the lockup clutch 11 cannot be secured, the engagement pressure of the lockup clutch 11 decreases. Then, since the engine load decreases, the discharge amount of the oil pump 28 increases and the engagement pressure of the lockup clutch 11 is increased.
In this way, a phenomenon in which the engagement pressure of the lockup clutch 11 is repeatedly increased and decreased, that is, so-called "hunting"
May occur.

Therefore, in this embodiment, when the hunting is caused, for example, when the affirmative judgment is made in any of the steps S1, S3 and S5, the second control mode is selected. It is prohibited. Therefore, hunting can be prevented in advance.

In the map shown in FIG. 2, the engagement area and the release area of the lockup clutch 11 are set, but the engagement area D1 is set as the slip area of the lockup clutch, and the engagement area D1 is set as the slip area based on this slip area. It is also possible to determine whether or not to select the control mode of No. 2 based on the flowchart shown in FIG. Further, the various “predetermined rotation speeds” described based on the flowchart of FIG. 1 are not always the same.

Here, the correspondence relationship between the configuration shown in FIG. 3 and the configuration of the present invention will be explained.
Corresponds to the fluid transmission device of the present invention, and the engine and the electric motor correspond to the driving force source of the present invention. Also, FIG.
The correspondence between the functional means shown in FIG. 3 and the present invention will be described. Steps S1 and S2 correspond to the condition determination means of the present invention, and steps S2 and S4 correspond to the first control of the present invention. Corresponds to the mode selection means, step S
2, S5, S6, S7, S8 and S9 are the second aspect of the present invention.
This corresponds to the control mode selecting means and the third control mode selecting means.

The correspondence between the matters described in the map of FIG. 2 and the present invention will be described. A solid line A1 and a broken line A2
The vehicle speed and the throttle opening which are divided by means the first condition of the present invention, and the vehicle speed and the throttle opening which are divided by the one-dot chain line C1 and the two-dot chain line C2 correspond to the second condition of the present invention.
Corresponds to the condition of. The engagement area B1 and the release area B2 defined by the solid line A1 and the broken line A2 correspond to the first control mode of the present invention, and the engagement area D1 and the engagement area D1 defined by the one-dot chain line C1 and the two-dot chain line C2 The release area B2 corresponds to the second control mode of the present invention.

Further, the correspondence between the matters described with reference to the flowchart of FIG. 1 and the matters of the present invention will be described. The matters described in steps S1 and S3 correspond to the third condition of the present invention. , The vehicle speed and the degree of change thereof, the engine speed, the oil discharge amount of the oil pump 28, the vehicle speed control request amount determined based on the signals of the brake switch 18 and the idle switch 30, and the like are related to the function of the actuator of the present invention. Equivalent to the physical quantity to be processed.

The characteristic configurations of the present invention disclosed based on the above specific examples are listed below. That is, the energy generating device (oil pump) is driven by the power of the driving force source of the vehicle, and the actuator (hydraulic pressure control) that controls the engagement state of the lockup clutch by the energy (discharging hydraulic pressure) generated by this energy generating device. Device) function is changed.

[0056]

As described above, according to the invention of claim 1,
As the control mode for controlling the engagement state of the lock-up clutch, the unstable state of the driving force or the rapid change of the driving force generated by selecting the second control mode is avoided in advance. Therefore, the power performance of the vehicle is improved and the drivability is improved.

According to the second aspect of the invention, it is possible to prevent a change in the rotational speed of the driving force source, for example, a predetermined rotational speed or less, when the lockup clutch is controlled based on the second control mode. It is possible to avoid insufficient driving force. Therefore, the power performance of the vehicle is improved and the drivability is improved.

[Brief description of drawings]

FIG. 1 is a flow chart showing an embodiment of the present invention.

FIG. 2 is an example of a map selected in the flowchart of FIG.

FIG. 3 is a conceptual diagram of a vehicle to which the present invention can be applied.

[Explanation of symbols]

2 ... Driving force source (engine, electric motor), 4 ... Torque converter, 5 ... Transmission, 6, 7, 12 ... Rotating member,
11 ... Lockup clutch, 13 ... Hydraulic control device,
14 ... Electronic control unit.

Claims (2)

[Claims] 1. A power transmission path of a vehicle, and
A lockup clutch having a function of controlling an engagement state of a lockup clutch arranged in parallel with a fluid transmission and capable of selecting a first control mode for controlling the lockup clutch according to a first condition. In the control device of, when a second condition different from the first condition is satisfied,
First determining means for further determining a third condition different from the first condition and the second condition, and a second control for controlling an engagement state of the lockup clutch according to the second condition. Whether to select the mode,
A second judging means for judging whether the third condition is satisfied or not; and a function of an actuator for controlling the lock-up clutch when the second control mode can be selected by the second judging means. A control device for a lockup clutch, comprising: a third determination means for further determining whether or not to select the second control mode based on a related physical quantity. 2. A vehicle power transmission path, and
A lockup clutch having a function of controlling an engagement state of a lockup clutch arranged in parallel with a fluid transmission and capable of selecting a first control mode for controlling the lockup clutch according to a first condition. In the control device of, when a second condition different from the first condition is satisfied,
First determining means for further determining a third condition different from the first condition and the second condition, and a second control for controlling an engagement state of the lockup clutch according to the second condition. Whether to select the mode,
Second determination means for determining whether the third condition is satisfied or not, and prediction of the rotation speed of the driving force source when the second control mode can be selected by the determination of the second determination means. A lock-up clutch control device comprising: a fourth determination means for further determining whether or not to select the second control mode based on a result.