JPH0694122A - Slip controller for lock up clutch - Google Patents

Abstract

PURPOSE:To attain the improvement of fuel cost at the time of ordinary deceleration not judged as sudden deceleration, by retaining a lock up clutch in a coupling state or at a predetermined slip rate, driving reversely an internal combustion engine by means of torque from a drive wheel side, obtaining a sufficiently long fuel cut period. CONSTITUTION:In a case in which the brake operation of a vehicle is conducted when the accelerator operation of the traveling vehicle is stopped and the full closure state of a throttle valve M2 is detected by means of a throttle full closure detecting means M3, it is decided by means of a sudden deceleration deciding means M4 whether it is sudden deceleration or not. At the time of sudden deceleration decision, a target slip rate is increased and set by means of a target slip rate setting means M6, and on the basis of this target slip rate, the slip rate of a lock up clutch is controlled by means of a slip rate controlling means M7. Meanwhile, at the time of ordinary deceleration that is not decided as sudden deceleration, the lock up clutch is retained in a coupling state or at a predetermined slip rate, and an internal combustion engine is driven reversely by means of torque that is from a drive wheel side, and the number of revolutions is reduced slowly.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a slip control device for controlling the slip ratio of a lockup clutch provided in an automatic transmission.

[0002]

2. Description of the Related Art As is well known, a lock-up clutch has been widely adopted in recent automatic transmissions, and the lock-up clutch is kept in an engaged state when the vehicle is traveling at a constant speed to prevent the internal combustion engine from operating. The rotation is transmitted to the transmission mechanism side without passing through the torque converter, thus preventing power loss due to slippage of the torque converter. Such a lockup clutch is released when the vehicle is stopped, and prevents the internal combustion engine from being stopped (so-called stalled) by the drive wheels that are blocked from rotating, but the lockup clutch is generally released. It is performed when the accelerator operation is stopped to decelerate the vehicle. That is, since it takes a little time to release the lockup clutch, if the lockup clutch is opened immediately before the vehicle is stopped, the lockup clutch cannot be released in time when the vehicle decelerates rapidly, and the internal combustion engine is stalled. There is a risk that it will end up, and in order to avoid this, there is a margin and it is opened in advance.

During deceleration of the vehicle, there is no risk of engine stalling even if the internal combustion engine is driven in reverse by the torque from the drive wheels and fuel injection is stopped. Therefore, it is aimed at improving fuel efficiency and reducing emissions. , The engine speed is within a predetermined rotation range (for example, 1600 rpm to 1000 rpm
(Range)), the fuel injection is temporarily interrupted, so-called fuel cut is performed. Therefore, in order to extend the fuel cut period (that is, the fuel injection interruption time) to achieve sufficient fuel efficiency improvement and emission reduction, the engine speed is gradually decreased during deceleration of the vehicle and the above-mentioned predetermined It is necessary to stop in the rotation area for a long time.

However, as described above, when the lock-up clutch is opened in association with the suspension of the accelerator operation, the internal combustion engine is not reversely driven by the torque from the driving wheel side, but the rotation speed is rapidly reduced. The fuel cut period was extremely short, and we could hardly expect to improve fuel efficiency or reduce emissions.

Therefore, as an example in which the engine speed is more gradually reduced when the vehicle is decelerating and the fuel cut period is extended, for example, Japanese Patent Laid-Open No. 1-2061.
The slip control device for the lock-up clutch described in Japanese Patent Laid-Open No. 59 and Japanese Patent Laid-Open No. 2-225875 is proposed.

[0006] These slip control devices switch the lockup clutch from the engaged state to the slip control state with a predetermined slip ratio when the vehicle speed decreases due to the suspension of the accelerator operation, and when the vehicle speed further decreases, the lockup occurs. It is controlled to release the clutch. Then, by the slip control performed at the time of deceleration, the internal combustion engine is reversely driven by the torque from the drive wheel side to gradually reduce the rotational speed, and the fuel cut period is extended.

In the slip control device disclosed in Japanese Patent Laid-Open No. 1-206159, two types of slip ratios are set in advance, and during slip control, the slip ratio is small in the high vehicle speed region (close to the fastening side). ) Is applied, and when the vehicle speed decreases to a low region, the slip ratio is switched to a large value (close to the open side). In addition, JP-A-2-22587
In the slip control device described in Japanese Patent Publication No. 5, for example, different slip ratios are applied during slip control during deceleration of the vehicle and at other times.

[0008]

DISCLOSURE OF THE INVENTION Problem to be Solved by the Invention
The slip control device for the lock-up clutch of a kind realizes the extension of the fuel cut period by slip-controlling the lock-up clutch at the time of deceleration of the vehicle as described above. No consideration is given to prevent stalling. That is, the lock-up clutch during slip control is released when the vehicle speed decreases to a preset release determination value, but during rapid vehicle deceleration, the vehicle speed decreases from the release determination value to 0 in a short time. However, there is a risk that the internal combustion engine will be stalled because the lockup clutch is not released in time. In the slip control device disclosed in Japanese Patent Laid-Open No. 1-206159, the lockup clutch is controlled at a slip ratio closer to the release side when the vehicle speed decreases to the release determination value.
This does not prevent stalling during sudden deceleration.

As a countermeasure, the openness judgment value is raised,
Although it is conceivable to release the lockup clutch early when the vehicle decelerates, another problem occurs that a sufficient fuel cut period cannot be obtained.

Therefore, the present invention provides a sufficiently long fuel cut period during deceleration of the vehicle to improve fuel efficiency and reduce emissions, and when the vehicle suddenly decelerates,
An object of the present invention is to provide a slip control device for a lockup clutch that can immediately prevent the engine from stalling by controlling the lockup clutch to the open side.

[0011]

As shown in FIG. 1, a slip control device for a lock-up clutch according to the present invention is a throttle full throttle for detecting a fully closed state of a throttle valve M2 of an internal combustion engine M1 mounted on a vehicle. Close detection means M3
And a sudden deceleration determination means M4 for determining whether or not a sudden deceleration is occurring when the vehicle is braked, and a fully closed state of the throttle valve M2 is detected by the throttle fully closed detection means M3 while the vehicle is traveling. It is determined whether or not the sudden deceleration determination means M4 has made a rapid deceleration determination.
Based on the target slip ratio setting means M6 for increasing and setting the target slip ratio of the lockup clutch in the automatic transmission M5 mounted on the vehicle, and the target slip ratio set by the target slip ratio setting means M6. And a slip ratio control means M7 for controlling the slip ratio of the lock-up clutch.

[0012]

In the present invention, when the accelerator operation of the running vehicle is stopped and the throttle fully closed detection means detects the fully closed state of the throttle valve, whether the rapid deceleration determination means makes a rapid deceleration determination. The target slip ratio setting means determines whether or not the target slip ratio of the lockup clutch is increased and set at the time of the rapid deceleration determination, and the slip ratio control means increases the actual slip ratio based on the target slip ratio. Controlled by.

Therefore, during normal deceleration without sudden deceleration determination, the lockup clutch is held in the engaged state or at a predetermined slip ratio, so that the internal combustion engine is reversely driven by the torque from the driving wheel side to moderate the rotational speed. It is possible to reduce and obtain a sufficiently long fuel cut period,
Moreover, when the rapid deceleration determination is made, the lockup clutch is immediately controlled to the disengagement side, so that the engine stall is reliably prevented.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A slip control device for a lockup clutch according to an embodiment of the present invention will be described below.

FIG. 2 is a schematic configuration diagram showing an internal combustion engine and an automatic transmission to which a slip-up control device for a lock-up clutch according to an embodiment of the present invention is applied.

As shown in the drawing, a throttle valve 3 is provided in the intake pipe 2 of the internal combustion engine 1, and the throttle valve 3 controls the amount of intake air supplied to the internal combustion engine 1 to adjust the engine output. It A transmission mechanism 7 is connected to a crankshaft 4 of the internal combustion engine 1 via a torque converter 6 of an automatic transmission 5 (for the sake of convenience, the transmission mechanism 7 is shown separately from the internal combustion engine 1), and the transmission mechanism 7 is not shown in the drawings. Is connected to the drive wheels via the drive system. A lock-up clutch 8 is installed in the torque converter 6, and the lock-up clutch 8 is switched between an open state and a fastened state by a hydraulic circuit (not shown) which is switch-controlled by a clutch control solenoid 9. , And an intermediate slip ratio between them is adjusted to an arbitrary slip ratio. As is well known, when the lockup clutch 8 is opened, the rotation of the internal combustion engine 1 is transmitted to the speed change mechanism 7 via the torque converter 6, and when the lockup clutch 8 is engaged,
It is transmitted to the speed change mechanism 7 via the lock-up clutch 8 without passing through the torque converter 6, while the rotation of the internal combustion engine 1 is rotated at a rate according to the slip ratio during the intermediate slip control. Is transmitted to the speed change mechanism 7 via.

An electronic control unit 11 (hereinafter, simply referred to as "ECU") for controlling the lock-up clutch 8 constitutes a logical operation circuit centering on a CPU, a ROM, and a RAM (not shown) and is used for clutch control of the hydraulic circuit. Solenoid 9
Is connected, and an idle switch 12 that detects the fully closed state of the throttle valve 3, a rotation speed sensor 13 that detects the rotation speed Ne of the internal combustion engine 1, and a vehicle speed V that is provided on the output side of the speed change mechanism 7 are detected. The vehicle speed sensor 14 is connected.

As will be described later, the ECU 11 determines, based on the rate of decrease ΔNe of the engine speed Ne detected by the engine speed sensor 13 per unit time during deceleration of the vehicle.
The actual slip ratio SLIP of the lockup clutch 8 is controlled to gradually reduce the rotation speed Ne of the internal combustion engine 1 to extend the fuel cut period, and at the time of sudden deceleration, the lockup clutch 8 is immediately controlled to the open side. Thus, the engine stall of the internal combustion engine 1 is prevented. The ECU 11 of the present embodiment not only controls the lockup clutch 8, but also controls the shift of the automatic transmission 5 and the operation control including the fuel cut of the internal combustion engine 1.

Next, the outline of the slip control executed by the slip control device for the lockup clutch constructed as described above will be described.

FIG. 3 is a time chart for explaining slip control during vehicle deceleration of the lock-up clutch slip control device according to one embodiment of the present invention, and FIG. 4 is a slip-up of the lock-up clutch according to one embodiment of the present invention. RO for determining the target slip rate from the rotation reduction rate of the control device
It is explanatory drawing which shows the map stored in M.

As shown in FIG. 3, while the vehicle is traveling at a constant speed, the throttle valve 3 of the internal combustion engine 1 is held at a predetermined opening by an accelerator operation to keep the engine speed Ne at a predetermined value, and the engine is locked. The up clutch 8 is engaged, that is, controlled to a slip ratio of 0%, and transmits the rotation of the internal combustion engine 1 to the transmission mechanism 7 without passing through the torque converter 6. Here, in order to decelerate the vehicle, first, when the accelerator operation is stopped prior to the brake operation, the throttle valve 3 is held in the fully closed state and the idle switch 12
Turn on.

At this time, the target slip rate SLIPTG of the lockup clutch 8 is set based on the rotation reduction rate ΔNe of the internal combustion engine 1 per unit time according to the map of FIG. That is, the target slip rate SLIPTG is set to a small value in a region where the rotation deceleration rate ΔNe is lower, and is set to a sharp increase in a region where the rotation deceleration rate ΔNe is lower than the preset sudden deceleration determination value BΔNe. Then, the duty ratio of the clutch control solenoid 9 is controlled based on the set target slip ratio SLIPTG, and the actual slip ratio SLIP is adjusted to the target slip ratio SLIPTG.

Here, the rapid deceleration determination value BΔNe is a rotation reduction rate that can occur when the vehicle is decelerating due to engine braking or a general gentle braking operation (hereinafter, simply referred to as "normal deceleration"). It is defined at the boundary between the region of ΔNe and the region of rotation reduction rate ΔNe that can occur when the vehicle is rapidly decelerating due to a sudden braking operation (hereinafter, simply referred to as “during deceleration”). Therefore,
At the time of normal deceleration (ΔNe <BΔNe), as shown in FIG. 3, the actual slip ratio S along with the target slip ratio SLIPTG.
The LIP is suppressed to a small value, and the internal combustion engine 1 is reversely driven by the torque from the drive wheel side to gently reduce the rotation speed Ne. Then, the rotation reduction rate ΔNe is the rapid deceleration determination value BΔN.
As long as the target slip ratio SLIPTG is not suppressed to a small value as long as e is not exceeded, the engine speed Ne remains for a long time in the rotation region where fuel cut is performed, and a sufficiently long fuel cut period is obtained.

Also, during this normal deceleration, a sudden braking operation is performed, and the vehicle is in a rapid deceleration state (ΔNe> BΔN).
When shifting to e), the target slip ratio SLIPTG rapidly increases and is set to a maximum value or a value close to it. That is, unlike the slip control device described in the related art, the lockup clutch 8 is not released at the time when the vehicle speed V decreases to the release determination value, but the vehicle starts decelerating earlier (rotational decrease). When the rate ΔNe exceeds the rapid deceleration determination value BΔNe), the lockup clutch 8 is immediately controlled to the disengagement side. Therefore, the engine stall of the internal combustion engine 1 due to the drive wheels of which rotation is blocked is reliably prevented.

That is, in comparison with the case where the lockup clutch 8 is released when the vehicle speed V drops to the release determination value, as in the slip control device described in the prior art,
Rather than earlier, the vehicle begins to slow down suddenly,
When the rotation reduction rate ΔNe exceeds the sudden deceleration judgment value BΔNe,
Immediately, the lockup clutch 8 is controlled to the open side.
Therefore, the engine stall of the internal combustion engine 1 due to the drive wheels of which rotation is blocked is reliably prevented.

On the other hand, although FIG. 3 shows the case where the vehicle running at constant speed transits to the sudden deceleration state through the normal deceleration state, the same applies when the vehicle decelerates directly from the constant speed traveling,
By controlling the lockup clutch 8 to the open side,
The engine stall of the internal combustion engine 1 is prevented.

As is well known, the actual slip ratio SLIP does not match the target slip ratio SLIPTG due to the power transmission action of the torque converter, and the target slip ratio SLIP
The actual slip ratio SLIP when TG is set to the maximum value is
For example, it is about 60%. Therefore, the target slip ratio SLIPTG in FIG. 4 is set in the range of about 0 to 60%. However, since the drive wheels are locked during the brake operation in FIG. 3, the actual slip ratio SLIP reaches 100%.

Next, a slip control process executed by the ECU 11 of the vehicle travel control device configured as described above will be described.

FIG. 5 is a flowchart showing a slip control routine executed by the ECU of the slip control device for the lockup clutch according to the embodiment of the present invention.

The routine shown in FIG. 5 is executed every 4 msec. The ECU 11 starts the idle switch 12 in step S1.
Is determined to be on, and if it is on, it is determined that the throttle valve 3 is fully closed and the vehicle is decelerating, and the process proceeds to step S2. Then, step S2
The engine speed Ne detected by the engine speed sensor 13 is 2
If it is less than 2000 rpm, it is determined that the lock-up clutch 8 is in the rotation region in which slip control is to be performed, and the process proceeds to step S3. Further, in step S3, it is determined whether the vehicle speed V detected by the vehicle speed sensor 14 is less than 40 km / h, and 40 km / h
If it is less than / h, it is determined that it is the speed range for slip control, and the process proceeds to step S4. Also, step S
When a negative determination is made in any of the processes from 1 to step S3, that is, when the vehicle is not decelerating, or when the engine speed Ne or the vehicle speed V is not in the region where the slip control should be performed, it is determined that the slip control need not be performed. , This routine ends.

When the affirmative determination is made in steps S1 to S3 and the process proceeds to step S4, it is determined whether the lockup clutch 8 is currently disengaged. When the lock-up clutch 8 is released, it is necessary to execute the slip control again because it is considered that the lock-up clutch 8 during slip control is released due to the decrease in the vehicle speed V in step S9 described later. Since this is not present, this routine ends.

Further, when the lockup clutch 8 is not released in step S4, that is, when the lockup clutch 8 is in the engaged state or during the slip control, it is determined in step S5 whether the vehicle speed V is less than 5 km / h. When the vehicle speed V is 5 km / h or more, as shown in FIG. 3, it is considered that the engine speed Ne is decreasing together with the vehicle speed V due to the suspension of the accelerator operation, and the slip control is performed after step S6. The process of is executed.

First, the ECU 11 calculates the engine speed decrease rate Ne of the internal combustion engine 1 per unit time based on the engine speed Ne detected by the engine speed sensor 13 in step S6, and in step S7 according to the map of FIG. Rotational reduction rate Δ
The target slip ratio SLIPTG is calculated from Ne. Furthermore,
In step S8, the duty ratio of the clutch control solenoid 9 is controlled based on the calculated target slip ratio SLIPTG to adjust the actual slip ratio SLIP to the target slip ratio SLIPTG, and then the process returns to step S1.

Therefore, after the accelerator operation shown in FIG. 3 is stopped, normal deceleration by engine braking is performed, so that the target slip ratio SLI is calculated according to the map shown in FIG.
The PTG is suppressed to a small value, and the internal combustion engine 1 is reversely driven by the torque from the drive wheel side to gently reduce the rotation speed Ne. Then, when the vehicle shifts to the sudden deceleration state due to the sudden braking operation, the target slip ratio SLIPTG is set to be rapidly increased, so that the lockup clutch 8 is immediately set.
Is controlled to the open side to prevent stalling.

In step S5, the vehicle speed V is 5 km / h.
If it is less than the target slip ratio SLIP in step S9
TG is set to the maximum value, the duty ratio of the clutch control solenoid 9 is controlled in step S8, and the actual slip ratio SLIP is set to the maximum value, that is, the open state. That is, the sudden braking operation as shown in FIG. 3 is not performed,
When the vehicle maintains the normal deceleration state until the stop, the rotation reduction rate ΔNe continues to be maintained at a value lower than the rapid deceleration determination value BΔNe. As a result, the target slip ratio SLIPTG is also suppressed to a small value, the lockup clutch 8 is not finally released, and the internal combustion engine 1 is stalled. Therefore, in the region where the vehicle speed V is less than 5 km / h (the region where the fuel cut has already ended), the lockup clutch 8 is opened regardless of the rotation reduction rate ΔNe to prevent the engine stall.

When the rotation reduction rate ΔNe slightly exceeds the rapid deceleration determination value BΔNe in step S7, the maximum value is not set as the target slip rate SLIPTG,
The lockup clutch 8 is not completely released. However, since the target slip ratio SLIPTG at this time is a value close to the maximum value, the operation amount required to open the lockup clutch 8 from that state is very small. Therefore, when the vehicle speed V decreases to less than 5 km / h, the lockup clutch 8 is quickly released in steps S9 and S8, and the engine stall of the internal combustion engine 1 is reliably prevented.

As described above, in this embodiment, the internal combustion engine M
1, the internal combustion engine 1 functions as the throttle valve M2, the throttle valve 3 functions as the throttle valve M2, the idle switch 12 functions as the throttle fully closed detection means M3, and the rapid deceleration determination means M4.
11 when executing the processing of step S6 as
However, the ECU 11 when the automatic transmission 5 as the automatic transmission M5 executes the processing of step S7 as the target slip ratio setting means M6, and the ECU 11 when the processing of step S8 as the slip ratio control means M7 respectively executes Function.

As described above, the slip control device for the lock-up clutch according to the present embodiment is the internal combustion engine 1 mounted on the vehicle.
Idle switch 12 for detecting the fully closed state of the throttle valve 3 and the idle switch 1 while the vehicle is traveling.
When the fully closed state of the throttle valve 3 is detected in 2, the decrease rate ΔNe of the engine speed Ne per unit time is calculated, and the calculated rotation decrease rate ΔNe is used for the rapid deceleration determination of the preset map. In a region lower than the value BΔNe, the target slip ratio SLIPTG of the lock-up clutch 8 in the automatic transmission 5 mounted on the vehicle is suppressed to a small value, and in a region higher than the rapid deceleration determination value BΔNe, it is regarded as a rapid deceleration. The ECU 11 controls the actual slip ratio SLIPTG of the lock-up clutch 8 based on the target slip ratio SLIPTG, which is set by rapidly increasing the target slip ratio SLIPTG.

Therefore, at the time of normal deceleration of the vehicle, the target slip ratio SLIPTG is suppressed to a small value, and the internal combustion engine 1 is reversely driven by the torque from the driving wheel side to gently reduce the rotational speed Ne, which is sufficient. A long fuel cut period can be obtained to improve fuel efficiency and reduce emissions. Further, when the vehicle suddenly decelerates due to an abrupt brake operation, the target slip ratio SLIPTG is rapidly increased and set, so that the lockup clutch 8 is immediately controlled to the open side, and the engine stall is reliably prevented. can do.

By the way, in the above embodiment, the engine speed N
The rotation reduction rate ΔNe is calculated from e, and the rotation reduction rate ΔN is calculated.
Although the target slip ratio SLIPTG corresponding to the deceleration state of the vehicle is calculated from the map based on e, the present invention is not limited to this, and the target slip ratio SLIPTG is not limited to this and the target slip ratio SLIPTG is used as a reference. May be calculated. Therefore, for example, when the vehicle decelerates, the vehicle speed sensor 1
The vehicle speed V is detected at 4, and when the decrease rate of the vehicle speed V is low, it is regarded as a normal deceleration state, and the target slip rate SLI is determined.
The target slip ratio SLIPTG may be increased by suppressing PTG to a small value, and when the decrease rate of the vehicle speed V is high, it is regarded as a rapid deceleration state. The turbine speed TNe detected by the turbine speed sensor 21 shown in FIG.
Also increases or decreases in proportion to the vehicle speed V, so that the target slip ratio SLIP is calculated based on the turbine speed TNe instead of the vehicle speed V.
TG may be set. Further, when the vehicle decelerates, the hydraulic pressure of the brake system of the vehicle is detected by the pressure sensor, and when the hydraulic pressure is low (the brake pedal force is small), it is regarded as a normal deceleration state and the target slip ratio SLIPTG is suppressed to a small value. However, when the hydraulic pressure is high (the brake pedal force is large), it may be regarded as a sudden deceleration state, and the target slip ratio SLIPTG may be increased.

Further, in the above embodiment, the rotation reduction rate ΔNe is determined by the rapid deceleration determination value BΔNe according to the characteristics of the map of FIG.
In the lower region, the target slip ratio SLIPTG is suppressed to a small value, and in the region higher than the rapid deceleration determination value BΔNe,
Although the target slip ratio SLIPTG is rapidly increased, the present invention is not limited to this, and the present invention is not limited to this.
The characteristics of the map can be changed appropriately. Therefore, for example, the target slip ratio SLIPTG may be set to 0 in the region lower than the rapid deceleration determination value BΔNe, and the target slip ratio SLIPTG may be set to the maximum value in the region higher than the rapid deceleration determination value BΔNe. Even in this case, the lockup clutch 8 can be immediately released at the time of sudden deceleration of the vehicle, and the engine stall can be prevented. Further, the target slip rate SLIPTG may be set in direct proportion to the rotation reduction rate ΔNe. That is, the braking operation performed by the driver can be roughly classified into a gentle operation during normal deceleration and an abrupt operation during rapid deceleration, and a braking operation corresponding to the middle thereof is not generally performed. Therefore, even when the target slip rate SLIPTG is made to be directly proportional to the rotation reduction rate ΔNe as described above, the actually used rotation reduction rate ΔNe is either in a low region or a high region, and therefore, during rapid deceleration, it is in a high region. Of the target slip rate SL having a large value based on the rotation decrease rate ΔNe of
The IPTG is set, and the engine stall of the internal combustion engine 1 can be prevented.

[0042]

As described above, according to the slip control device of the lock-up clutch of the present invention, the lock-up clutch is held in the engaged state or at the predetermined slip ratio during the normal deceleration without the rapid deceleration determination. , The internal combustion engine is reversely driven by the torque from the drive wheels to gradually reduce the rotation speed, obtain a sufficiently long fuel cut period, improve fuel efficiency and reduce emissions, and make a sudden deceleration determination. At times, the lockup clutch is immediately controlled to the disengagement side, so that the engine stall can be reliably prevented.

[Brief description of drawings]

FIG. 1 is a claim correspondence diagram conceptually showing the content of one embodiment of the present invention.

FIG. 2 is a schematic configuration diagram showing an internal combustion engine and an automatic transmission to which a slip control device for a lockup clutch according to an embodiment of the present invention is applied.

FIG. 3 is a time chart for explaining slip control during vehicle deceleration by the lock-up clutch slip control device according to one embodiment of the present invention.

FIG. 4 is an explanatory view showing a map stored in a ROM for determining a target slip ratio from a rotation reduction ratio of a slip control device for a lockup clutch according to an embodiment of the present invention.

FIG. 5 is a flowchart showing a slip control routine executed by the ECU of the slip control device for the lockup clutch according to the embodiment of the present invention.

[Explanation of symbols]

 M1 Internal combustion engine M2 Throttle valve M3 Throttle fully closed detection means M4 Rapid deceleration determination means M5 Automatic transmission M6 Target slip ratio setting means M7 Slip ratio control means 1 Internal combustion engine 3 Throttle valve 5 Automatic transmission 8 Lockup clutch 11 ECU 12 Idle switch

Claims (1)

[Claims] 1. A throttle fully closed detection means for detecting a fully closed state of a throttle valve of an internal combustion engine mounted on a vehicle, a sudden deceleration determination means for determining whether or not a sudden deceleration occurs when a vehicle brake is operated, When the throttle fully closed detection means detects the fully closed state of the throttle valve during traveling, the rapid deceleration determination means determines whether or not a rapid deceleration determination is made. Target slip ratio setting means for increasing and setting the target slip ratio of the lockup clutch in the automatic transmission mounted on the lockup clutch of the lockup clutch based on the target slip ratio set by the target slip ratio setting means. A slip control device for a lock-up clutch, comprising: a slip ratio control means for controlling a slip ratio.