JP2001221341A - Slip control device of vehicular lockup clutch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable inertial travel, and to improve drivability of a vehicle by properly restraining a lockup clutch from being adjusted to the direct connection side in a slip control device of the vehicular lockup clutch. SOLUTION: When a speed reduction slip control starting condition (S1: Y), is satisfied by peforming processing (S5, S6, S7) for controlling the lockup clutch to the direct connection side by setting a target slip value to an ordinary target slip value, the engine speed of an engine is increased, a fuel cut area is expanded, fuel consumption is restrained, and the so-called engine brake is applied to the vehicle to increase speed reduction force. However, when requiring to continue inertial travel in a state of an idle switch turned on, when the engine brake is applied in this way, drivability of the vehicle reduces. Then, when an inertial travel determining condition (S2: Y), is satisfied, processing (S8) for increasingly correcting the target slip value is performed to enable the inertial travel.

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 lock-up clutch for a vehicle, and more particularly, to controlling the lock-up clutch to a direct connection side so that braking is applied to the vehicle as required. The present invention relates to a vehicle lock-up clutch slip control device that can be suppressed.

[0002]

2. Description of the Related Art Conventionally, in a vehicle in which a driving force generated by an internal combustion engine is transmitted to driving wheels via a hydraulic power transmission means such as a torque converter or a fluid coupling, an input shaft of the hydraulic power transmission means is connected to an input shaft of the vehicle. It has been considered to provide a lock-up clutch for adjusting the connection state with the output shaft. In these vehicles, the fuel consumption can be suppressed and the deceleration force of the vehicle can be increased by adjusting the engagement state of the lock-up clutch to the direct connection side during deceleration (for example, Japanese Patent No. 2576733, Japanese Unexamined Patent Application Publication No. H05-265,1993). -2
No. 31530, JP-A-7-103329).

[0003] That is, in this type of vehicle, when the throttle opening is equal to or less than a predetermined value and the rotational speed of the internal combustion engine is higher than a predetermined fuel cut rotational speed, fuel cut control for performing fuel cut to the internal combustion engine is performed. Will be When the lock-up clutch is adjusted to the direct connection side during deceleration (normally, the throttle opening is equal to or less than the predetermined value), the rotation speed of the drive wheels increases the rotation speed of the internal combustion engine, and the rotation speed is higher than the fuel cut rotation speed. It is possible to suppress the fuel consumption by enlarging the holding period, that is, the fuel cut region. Further, by transmitting the rotation of the drive wheels to the internal combustion engine, a so-called engine brake is applied to the drive wheels, and the deceleration force of the vehicle can be increased.

[0004]

However, according to the above-mentioned prior art, when the driver releases his / her foot from the accelerator pedal to reduce the throttle opening during traveling, the engine brake is unconditionally applied. When the vehicle is traveling at a constant speed at a high speed on a highway or the like, the driver tries to coast without reducing the current vehicle speed so much.
When the driver releases his foot from the accelerator pedal, engine braking is applied and the vehicle speed decreases.

Accordingly, the present invention provides a slip control device for a lock-up clutch for a vehicle as described above, in which the lock-up clutch is appropriately prevented from being adjusted to the directly connected side to enable coasting, thereby enabling the vehicle to run. The purpose was to improve the performance.

[0006]

Means for Solving the Problems and Effects of the Invention To achieve the above object, the invention according to claim 1 comprises a hydraulic power transmission means, a lock-up clutch, a throttle opening detection means, a slip opening A gist of the present invention is a slip control device for a lock-up clutch for a vehicle, comprising a control unit, an obstacle detection unit, and a suppression unit.

That is, the fluid power transmission means is provided in a power transmission path from the internal combustion engine of the vehicle to the drive wheels. The lock-up clutch adjusts a connection state between the input shaft and the output shaft of the hydraulic power transmission means. The throttle opening detecting means detects a throttle opening of the internal combustion engine. The slip control means controls the lock-up clutch to adjust the connected state to the directly connected side when the throttle opening detected by the throttle opening detecting means becomes less than or equal to a predetermined value while the vehicle is running. Therefore, in the present invention, as described above, during deceleration (the throttle opening is usually equal to or less than the predetermined value), it is possible to suppress fuel consumption and increase the deceleration force of the vehicle.

The obstacle detecting means detects an obstacle existing in the traveling direction of the vehicle. The suppression unit suppresses the control of the slip control unit when the obstacle detection unit does not detect an obstacle, or when the obstacle detection unit detects the obstacle and the distance to the obstacle is a predetermined distance or more. When there is no obstacle in the traveling direction of the vehicle, or when the obstacle is present but the distance to the obstacle is a predetermined distance or more, the driver often does not intend to decelerate. Thus, in the present invention, in such a case, the lock-up clutch is prevented from being adjusted to the directly connected side, and good coasting is enabled. Therefore, according to the present invention, it is possible to appropriately control the lock-up clutch from being adjusted to the direct connection side, thereby enabling coasting, and improving the drivability of the vehicle.

According to a second aspect of the present invention, there is provided a hydraulic power transmitting means, a lock-up clutch, a throttle opening detecting means, a slip controlling means, a brake operation detecting means,
And a slip control device for a lock-up clutch for a vehicle, comprising: Among them, the hydraulic power transmission means, the lock-up clutch, the throttle opening detection means, and the slip control means are configured in the same manner as in claim 1, and as described above, the fuel consumption is suppressed during deceleration and the vehicle is controlled. The deceleration force can be increased.

The brake operation detecting means detects the operation state of the brake of the vehicle. The suppression unit suppresses the control of the slip control unit when the brake operation detection unit does not detect that the brake is being operated. When the driver tries to coast, the brake is not operated. Thus, in the present invention, in such a case, the lock-up clutch is prevented from being adjusted to the directly connected side, and good coasting is enabled. Therefore, in the present invention, it is possible to allow coasting by appropriately suppressing the lock-up clutch from being adjusted to the directly connected side,
Drivability of the vehicle can be improved.

According to a third aspect of the present invention, in addition to the configuration of the second aspect, an obstacle detecting means is further provided. And
The obstacle detecting means detects an obstacle existing in the traveling direction of the vehicle, and the suppressing means detects the obstacle when the obstacle detecting means does not detect the obstacle or when the obstacle detecting means detects the obstacle. Only when the distance to the object is equal to or more than a predetermined distance, the control by the slip control means is suppressed.

That is, according to the present invention, when both the condition referred to for enabling the coasting in claim 1 and the condition referred to for enabling the coasting in claim 2 are satisfied, It enables coasting. Therefore, according to the present invention, in addition to the effect of the invention described in claim 2, it is possible to more appropriately match the intention of the driver to enable / disable the coasting, and to further improve the drivability of the vehicle. There is an effect that the fuel consumption can be more appropriately suppressed by appropriately executing the fuel cut.

According to a fourth aspect of the present invention, in addition to the configuration according to any one of the first to third aspects, the rate of change of the throttle opening detected by the throttle means by the throttle opening detecting means is equal to or less than a predetermined value. The control of the slip control means is suppressed only when

When the driver intends to coast, the operation of the accelerator becomes slow, so that the rate of change of the throttle opening becomes equal to or less than the predetermined value. Thus, in the present invention, only in such a case, the lockup clutch is prevented from being adjusted to the directly connected side, and the coasting is enabled. Therefore, according to the present invention, in addition to the effect of the invention according to any one of claims 1 to 3, it is possible to more appropriately match whether or not to enable the coasting to the driver's intention, and to improve the drivability of the vehicle. Is further improved, and the fuel cut can be appropriately executed to thereby more effectively suppress fuel consumption.

According to a fifth aspect of the present invention, in addition to the structure of any of the first to fourth aspects, a vehicle speed detecting means is further provided. Then, the vehicle speed detecting means detects the vehicle speed of the vehicle, and the suppressing means suppresses the control of the slip control means only when the vehicle speed detected by the vehicle speed detecting means is within a predetermined range.

[0016] In many cases, the vehicle speed when the driver tries to coast is likely to fall within a predetermined range. Therefore, in the present invention, only when the vehicle speed is within the above-mentioned predetermined range, the lock-up clutch is prevented from being adjusted to the directly connected side to enable coasting. Therefore, according to the present invention, in addition to the effect of the invention described in any one of claims 1 to 4, whether or not to enable the inertial running can be more favorably matched to the driver's intention, and the drivability of the vehicle can be improved. Is further improved, and the fuel cut can be appropriately executed to thereby more effectively suppress fuel consumption.

According to a sixth aspect of the present invention, in addition to the configuration according to any one of the first to fifth aspects, an acceleration detecting means is further provided. Then, the acceleration detecting means detects the acceleration of the vehicle, and the suppressing means suppresses the control of the slip control means only when the acceleration detected by the acceleration detecting means is within a predetermined range.

In many cases, the acceleration of the vehicle when the driver tries to coast is likely to fall within a predetermined range. Therefore, in the present invention, the coasting is enabled by suppressing the lock-up clutch from being adjusted to the direct connection side only when the acceleration is within the predetermined range. Therefore, according to the present invention, in addition to the effect of the invention described in any one of claims 1 to 5, enabling / disabling the coasting can be more favorably matched to the driver's intention, and the drivability of the vehicle can be improved. Is further improved, and the fuel cut can be appropriately executed to thereby more effectively suppress fuel consumption.

[0019]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is an explanatory diagram schematically showing a power transmission path of a vehicle to which the present invention is applied. As shown in FIG. 1, a power transmission path from an engine 1 as an internal combustion engine to a drive wheel 2 (here, a rear wheel) is provided with a torque converter 3 as a fluid power transmission means, an automatic transmission 4,
And a differential gear 5 are sequentially provided.

The engine 1 is a well-known gasoline engine that draws an air-fuel mixture through an intake pipe 11 and explodes to rotate a crankshaft 12. A throttle valve 13 that adjusts the amount of air intake interlocks with an accelerator pedal 14. ing. The torque converter 3 includes a pump wheel 31 connected to the crankshaft 12 of the engine 1, a stator wheel (not shown), and the pump wheel 3 fixed to the input shaft 41 of the automatic transmission 4.
Turbine wheel 3 which is rotated by receiving oil from 1
2 and a lock-up clutch 33 that is swingably connected to the input shaft 41. Torque converter 3
The automatic transmission 4 is connected to a hydraulic control circuit 51 and is controlled as follows.

The lock-up clutch 33 swings by receiving a pressure corresponding to the operation of a solenoid SLU (not shown) of the hydraulic control circuit 51, and adjusts the connection between the crankshaft 12 and the input shaft 41. Normally, the lock-up clutch 33
Is controlled to the open side, and the crankshaft 12 and the input shaft 4
The power transmission between the first and second motors is performed through the fluid pressure of the oil. When the lock-up clutch 33 is controlled to the engagement side by the operation of the solenoid SLU, the crankshaft 12 and the input shaft 41 are directly connected to each other, and power transmission between them is also performed by mechanical friction of the lock-up clutch 33. The automatic transmission 4 is a well-known automatic transmission having a large number of planetary gear mechanisms, a multi-plate clutch and a brake, and is one of first to fourth speeds depending on the operation state of solenoids SL1 and SL2 (not shown) of the hydraulic control circuit 51. Can be switched.

The solenoid SL of the hydraulic control circuit 51
The electronic control circuit 60 for controlling U, SL1, and SL2 has C
The microcomputer is configured as a microcomputer including a PU 61, a ROM 62, and a RAM 63, and calculates the control amounts of the solenoids based on the following various input signals.

That is, the electronic control circuit 60 includes a throttle sensor 71 with an idle switch (hereinafter simply referred to as a throttle sensor) as throttle opening detecting means for detecting the opening θ of the throttle valve 13, and the rotation of the engine 1. An engine speed sensor 72 for detecting the speed NE (engine speed), an input shaft speed sensor 73 for detecting the speed NT (turbine blade speed) of the input shaft 41 of the automatic transmission 4, an automatic transmission 4 is connected to a counter shaft rotation sensor 74 for detecting the rotation speed NOUT of the counter shaft 42. Signals corresponding to the throttle opening .theta. And the rotation speeds NE, NT and NOUT are input from these sensors. I have. The electronic control circuit 60
Further, from the operation position sensor 75, a signal indicating the operation position (any of L, 2, 3, D, N, R, and P ranges) of the shift operation lever 76 is output from a brake sensor 77 as a brake operation detecting means. , An STP signal which is turned on when the brake pedal 78 is operated, and data relating to a preceding obstacle are input from the laser radar 79 for cruise control.

Next, the processing executed by the electronic control circuit 60 in this power transmission path will be described with reference to the flowcharts of FIGS. FIG. 2 shows an electronic control circuit 60.
5 is a flowchart illustrating a main routine of deceleration slip control executed by the control unit. Note that the electronic control circuit 60 executes this process at predetermined time intervals while the vehicle is running.

As shown in FIG. 2, when the process is started, the electronic control circuit 60 determines whether or not a deceleration slip control start condition is satisfied in S1 (S represents a step: the same applies hereinafter). Here, the deceleration slip control start condition is that the following precondition (1) is satisfied,
The condition is satisfied when all of the following conditions (2) to (10) are satisfied. First, the precondition of (1) is that <1> solenoid S1 is normal, <2> solenoid S2 is normal, <3> solenoid SLU is normal, <4> counter shaft rotation sensor 7
4 is normal, <5> input shaft rotation sensor 73 is normal, <6>
Oil temperature sensor is normal, <7> water temperature sensor is normal, <8> S
The third-speed and fourth-speed prohibition control by the FT is not being executed. <9
> The lock-up permission condition by the engine coolant temperature sensor is satisfied, <10> the throttle sensor 71 is normal, <11> traction control is not performed, <1.
2> All the conditions that the operation position of the shift operation lever 76 is not in the R range, the N range, or the L range are satisfied.

Next, the conditions (2) to (10) are as follows. (2) Slip control by judder is not prohibited (3) Idle switch of throttle sensor 71 is ON
It is. (4) Oil temperature ≧ 50 ° C. (5) Oil temperature <110 ° C. (6) Water temperature ≧ −40 ° C. (7) t_SPD ≦ vehicle speed <100km / h where t_SPD: 38km / h at 2nd speed, 45km / h at 3rd speed
50km / h at h, 4th speed (8) All the following conditions are satisfied. 3rd speed, 4th speed output (However, 1st speed, 2nd speed to 3rd speed, 4th speed
(When upshifting to high speed, after shifting is complete.) VNSLP ≧ −50 rpm where VNSLP = NE−NCO VNSLP: actual slip value (rotation speed) NE: engine rotation speed NCO: counter shaft rotation speed NOUT × gear ratio (9) Within 80 ms after the above-mentioned idle switch is turned on (10) ) When the operation position of the shift operation lever 76 is in the D range or three ranges or more and the deceleration slip start condition is satisfied (S
1: Y), the process proceeds to the subsequent S2, and if not satisfied (S1: N), the process is once ended as it is. Next, in S2, it is determined whether or not the coasting determination condition is satisfied. This determination is made based on whether or not an inertia determination flag set in an inertia traveling determination process (FIG. 3) described later is ON. When the engine 1 starts (vehicle speed =
At 0), the inertia determination flag is OFF, and in this case, a negative determination is made and the process proceeds to S3.

In S3, it is determined whether or not the process of returning to the target slip value is being performed. That is, the target slip value is corrected in S8 described later, and it is determined whether or not a process of returning the corrected target slip value to the normal target slip value has been performed. At first, a negative determination is made here, and the process proceeds to S4. In S4, it is determined whether or not the coasting process was being executed last time, and here, a negative determination is made and the process proceeds to S5. In S5, the routine proceeds to S6 with the normal target slip value generally used when performing the slip control of the lock-up clutch 33 as the target slip value. In S6, the target slip value calculated by the processing up to that time is stored as a determined value in a predetermined amount area of the RAM 63, and in S7, the lock-up clutch 33 is controlled so that the actual slip value approaches the target slip value. A lock-up slip execution process is executed, and the process is temporarily terminated.

When the processing (S5 to S7) for setting the target slip value to the normal target slip value and controlling the lock-up clutch 33 to the directly connected side is performed, the rotational speed NE of the engine 1 is obtained.
, The fuel cut area is enlarged, fuel consumption is suppressed, and the deceleration force can be increased by applying a so-called engine brake to the vehicle. However, when it is desired to continue coasting with the idle switch turned on, the drivability of the vehicle is reduced when the engine brake is applied in this manner. The inertia determination flag referred to in S2 is a flag indicating whether or not such inertia traveling should be performed. Here, the coasting determination processing for setting the coasting determination flag will be described with reference to the flowchart of FIG.

As shown in FIG. 3, when the process is started, the electronic control circuit 60 determines in S21 whether or not the operation position of the shift operation lever 76 is in the D range or the 3 range from the operation position sensor 75. Make a decision based on the signal. If it is the D range or the 3 range (S21: Y), S2
The process proceeds to 2 to determine whether there is a vehicle traveling ahead or a vehicle interrupting ahead based on data from the laser radar 79. In S22, when a target slip value correction process (S8) described later has not been executed yet, an affirmative determination is made when there is no vehicle (front vehicle) within 30m ahead, and during execution of the target slip value correction process, An affirmative determination is made when another vehicle (interrupted vehicle) does not interrupt the preceding recognized vehicle.

If there is no preceding vehicle or interrupting vehicle (S2
2: Y) Then, the process proceeds to S23, where it is determined whether or not the vehicle speed is the coasting determination permission speed (for example, 40 km / h ≦ vehicle speed <95 km / h) based on the aforementioned rotation speed NOUT. If the vehicle speed is the coasting determination permission speed (S23: Y), the subsequent S
24, it is determined based on a signal from the throttle sensor 71 whether or not the throttle opening θ is smaller than a predetermined value KTADA.

If θ <KTADA (S24: Y),
The process proceeds to S25, and it is determined whether or not the rate of change of the throttle opening θ is equal to or less than a predetermined value. If the rate of change of the throttle opening θ is equal to or less than the above-mentioned fixed value, (S2
5: Y), the process proceeds to S26, and the STP signal input by the brake sensor 77 in response to the operation of the brake pedal 78 becomes O.
It is determined whether or not it is FF. When the STP signal is OFF (Y in S26), the process proceeds to S27, and the actual vehicle acceleration is within a certain range (for example, 100 × 10 ⁻³ [G] ≦ the actual vehicle acceleration ≦ 0 × 10 ⁻³ [G]). Is determined. When the actual vehicle acceleration is within the above range (S27: Y),
In S28, the inertia determination flag is set to ON, and the process is terminated once.

On the other hand, if a negative determination is made in any of S21 to S26, the flow shifts to S29 and the inertia determination flag is set to OF.
After setting to F, the processing is once ended. When it is determined in S27 that the actual vehicle acceleration is out of the above range (S27: N), it is determined whether or not lockup is being executed (S27).
31) and whether NE / NT <1.0 is satisfied (S3
2) are sequentially determined, and lock-up is being executed (S31:
Y) and if NE / NT <1.0 (S32:
Y), the process proceeds to S28, and the inertia determination flag is set to ON. When a negative determination is made in S31 or S32, the process proceeds to S29, and the inertia determination flag is turned off.
Set to. The processes of S31 and S32 are performed when the process shifts to the deceleration slip control during the lock-up execution (S1:
Y) This is a process that takes into account that the initial deceleration force is so large that it is difficult to enter the inertial running.

Returning to FIG. 2, when the above-described deceleration slip control start condition is satisfied (S1: Y) and the inertia determination flag is set to ON by the above-described inertial running determination processing (S28), S2 is performed. Then, the process proceeds to S8 to execute a target slip value correction process. The details of this process are shown in FIG.

As shown in FIG. 4, in this processing, first, S
At 81, it is determined whether or not the region is a region where the correction value is gradually reflected. In this step, the actual slip value VN
Based on the SLP (= NE-NCO) and the vehicle speed, it is determined using the map of FIG. 5 whether the correction value is in the area where the correction value is gradually reflected or in the area where the correction value is reflected at one time.

The map shown in FIG. 5 shows that the change of the target slip value in a region where the actual slip value is larger than a certain value (here, 400 rpm) and the vehicle speed is larger than a certain value (here, 60 km / h). Is set to reflect the correction value at one time because it seems to have little effect on the behavior of the vehicle, and to gradually reflect the correction value in a region where the change in the target slip value may affect the behavior of the vehicle. ing.

If the correction value is in the area where the correction value is reflected at one time (S81: N), the flow goes to S6 and S7 at S82 with the target slip value as the corrected MAX value shown in Table 1.
Then, as shown in Table 1, the actual slip value approaches the corrected MAX value corresponding to the inter-vehicle distance with the preceding vehicle,
The lock-up clutch 33 is controlled.

[0037]

[Table 1]

The target slip value correction processing (S
Since the start condition of 8) requires that the inter-vehicle distance to the preceding vehicle exceeds 30 m (S22), the corrected MAX value is set to 400 rpm at the start of this process. Thereafter, an affirmative determination is made in S22 unless another vehicle is interrupted. Therefore, Table 1 also defines a corrected MAX value corresponding to an inter-vehicle distance of less than 30 m. When the inter-vehicle distance to the vehicle in front is less than 5 m, the target slip value correction process is interrupted, and the above-mentioned inertia determination flag is set to OF.
F may be configured.

On the other hand, when it is determined in S81 that the actual slip value and the vehicle speed are in the region where the correction value is gradually reflected (S81: Y), the flow shifts to S83, where the current target slip value (current target slip value) is set. ) Are added with the correction values shown in Table 2.

[0040]

[Table 2]

As shown in Table 2, this correction value also corresponds to the inter-vehicle distance to the preceding vehicle. In subsequent S84, S83
It is determined whether or not the corrected target slip value is larger than the above-described corrected MAX value (Table 1). If the value is equal to or less than the corrected MAX value (S84: N), the process directly proceeds to S6, and if the value exceeds the corrected MAX value (S84).
84: Y) The process proceeds to S82 described above. If the vehicle is in the region where the correction value of FIG. 5 is gradually reflected by this processing (S81: Y), the target slip value is gradually increased by the above correction value (S83), and when the corrected MAX value is reached. Guarding can be performed so as not to exceed the MAX value after the correction (S84, S82).

As described above, in the present embodiment, when the coasting determination condition is satisfied (S2: Y), the target slip value is set to a value larger than usual (S82 to S84), and the actual slip value is set to that value. The lock-up clutch 33 can be controlled so that the value approaches (S6, S7). Therefore, when it is desired to continue the coasting with the idle switch turned on, it is possible to suppress the application of the engine brake and secure the drivability of the vehicle. Hereinafter, S8 ~
A series of processing of S7 is also called coasting processing.

Next, returning to FIG. 2, the processing in the case of returning from the coasting processing will be described. If the coasting determination condition is not satisfied (S2: N), the process proceeds to S3 to determine whether or not the process of restoring the target slip value is in progress. Then, it is determined whether or not the coasting process was being executed last time. Since the coasting process was being executed last time (S4:
Y) After setting the target slip recovery flag in S9, the process proceeds to S10 to determine the inter-vehicle distance of the preceding vehicle.
If the inter-vehicle distance is large (for example, 10 m or more), continue S1
The process proceeds to S12, in which control is performed to gradually return the target slip value to the normal target slip value. That is, 1/4 of the value obtained by subtracting the normal target slip value from the current target slip value is subtracted from the current target slip value to obtain a new target slip value (S
11), the lower limit is guarded by the normal target slip value (S12, S5).

In the second and subsequent processes after the inertia traveling determination condition is not satisfied (S2: N), since the target slip recovery flag is set, an affirmative determination is made in S3.
The process jumps directly from S4 and S9 to S10. Through this processing, the target slip value is reduced by a value obtained by subtracting the normal target slip value from the current target slip value and dividing by 4 (once calculated, the fixed value is set regardless of the change in the current target slip value). When the slip value is reached (S1
2: Y), guard can be performed with the normal target slip value (S5).

On the other hand, in S10, the inter-vehicle distance is small (for example, 1
0m) (S10: N), directly to S5
And immediately returns the target slip value to the normal target slip value. With this processing, the engine brake is immediately applied to the vehicle, and the rear-end collision with the vehicle ahead can be favorably avoided. When the process proceeds from S10 or S12 to S5, the above-described target slip recovery flag is reset.

Next, the operation and effect of the above processing will be described with reference to the time charts of FIGS. 6 to 8, the rotational speed NE of the engine 1 and the rotational speed NCO of the clutch (not shown) of the automatic transmission 4 (= N
OUT × gear ratio) and vehicle speed SPD, target slip value, actual acceleration of the vehicle, throttle opening θ, drive duty (SLU_DUTY) of the solenoid SLU corresponding to the control pressure of the lock-up clutch 33, and the above-mentioned inertial running determination condition Is established / not established.

When the automatic transmission switches from the third speed to the fourth speed at time t0 shown in FIG. 6, N
E and NCO decrease, and the target slip value also changes. Then, the throttle opening .theta. Decreases from the time point t1 so that the condition for starting the deceleration slip control is satisfied (S1:
Y), the target slip value decreases until time t2 (S
5) SLU_DUT to achieve the target slip value
Y increases (S7). With this slip control, NE
Is maintained higher than the fuel cut speed,
That is, fuel consumption can be suppressed by expanding the fuel cut region.

Further, assuming that the coasting determination condition is satisfied during the period indicated by arrow A, the coasting determination flag is set to O at time t3.
N (S2: Y), and the coasting process is performed (S2).
8 to S7). FIG. 6 shows a case where the correction value is gradually reflected (S
81: Y), and after time t3, the target slip value gradually increases until reaching the corrected MAX value (S83).
To S82), to achieve the target slip value, SLU_
DUTY also decreases gradually. As a result, the absolute value of the actual acceleration (deceleration) of the vehicle is kept small, and good coasting is possible. Then, until time t4 when the inertia determination flag is turned off due to the decrease in the vehicle speed SPD (S23:
N), this coasting is continued.

FIG. 7 illustrates a case where coasting is stopped due to depression of the accelerator pedal 14. The operation up to time t3 is the same as in FIG. In the example of FIG. 7, the accelerator pedal 14 is gradually depressed from time t5, and the throttle opening θ increases accordingly. At time t6, the throttle opening .theta.
When it becomes ADA or more (S24: N), the inertia determination flag is turned off (S29), and the inertial running process is stopped.
In addition, due to the increase in the throttle opening θ, the inertia determination flag is turned off, and then the deceleration slip control is also stopped.

FIG. 8 illustrates a case where the coasting is stopped due to the interruption of the vehicle. The operation up to time t3 is the same as in FIG. When the interruption of the vehicle is detected at time t7 (S22: N), the inertia determination flag is turned off (S29). In FIG. 8, when the inter-vehicle distance to the interrupted vehicle is relatively large (S10:
After the time point t7, the target slip value gradually decreases (S11, S12, S5), and the SLU_DUTY gradually increases accordingly (S7). As a result, the engine brake is applied to the vehicle, and the deceleration (absolute value of the negative actual acceleration) of the vehicle is increased, so that a rear-end collision with the vehicle in front can be satisfactorily avoided. Further, when the brake pedal 78 is depressed at time t8, the vehicle rapidly decelerates, and the deceleration slip control is also stopped.

As described above, in the present embodiment,
It is possible to improve the drivability of the vehicle by executing a coasting traveling process that allows the traveling by inertia by appropriately suppressing the lockup clutch 33 from being adjusted to the direct connection side. Moreover, in the above embodiment, the operation position of the shift operation lever 76, the presence or absence of a forward vehicle or an interrupting vehicle, the vehicle speed, the throttle opening, the rate of change of the throttle opening, and the brake pedal 78
Is switched between performing and not performing the coasting process based on the operation state of the vehicle and the actual acceleration of the vehicle. Therefore, whether or not the coasting process is performed can be more favorably matched to the driver's intention, and the drivability of the vehicle is further improved, and the fuel cut is appropriately executed to further suppress the fuel consumption. Can be.

It is not always necessary to refer to all of the above-mentioned conditions for switching between performing and not performing the inertial running process, and an arbitrary part (one or more) may be used.
It is also possible to switch between performing and not performing the inertial running process with reference to only. However, the more the conditions to be referred to, the better the match between the driver's intention and whether or not to perform the inertial running process can be made, and the drivability of the vehicle can be further improved, and the fuel cut can be appropriately executed to execute the fuel cut. Needless to say, consumption can be suppressed better.

In the above-described embodiment, the laser radar 79 corresponds to the obstacle detecting means, the counter shaft rotation sensor 74 corresponds to the vehicle speed detecting means and the acceleration detecting means, and the electronic control circuit 60 corresponds to the slip controlling means and the suppressing means. And
Among the processes of the electronic control circuit 60, the process of S5 corresponds to a slip control unit, and the process of S8 corresponds to a suppression unit. It should be noted that the present invention is not limited to the above embodiment at all, and can be implemented in various forms without departing from the gist of the present invention.

For example, in the above-described embodiment, the presence or absence of a preceding vehicle or an interrupting vehicle is detected based on data from the laser radar 79 to switch between performing and not performing inertial running processing. Even when an obstacle is detected, the coasting process may be prohibited. The road curve state is detected based on data from the laser radar 79 and data from the car navigation device, and the coasting process is performed based on the detected condition. You may switch between and not. Further, in the above-described embodiment, the coasting process can be started when no vehicle is detected within 30 m ahead, but the coasting process may be started only when no vehicle is detected.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram schematically showing a power transmission path of a vehicle to which the present invention is applied.

FIG. 2 is a flowchart illustrating a main routine of deceleration slip control.

FIG. 3 is a flowchart illustrating an inertia traveling determination process.

FIG. 4 is a flowchart illustrating a target slip value correction process.

FIG. 5 is an explanatory diagram showing a map used in the processing.

FIG. 6 is a time chart showing the operation of each part of the vehicle by the above-described processing.

FIG. 7 is a time chart showing the above-mentioned operation when the accelerator pedal is depressed.

FIG. 8 is a time chart showing the above operation when another vehicle is interrupted.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Engine 2 ... Drive wheel 3 ... Torque converter 4 ... Automatic transmission 13 ... Throttle valve 14 ... Accelerator pedal 31 ... Pump impeller 32 ... Turbine impeller 33 ... Lock-up clutch 51 ... Hydraulic control circuit 60 ... Electronic control circuit 71 ... Throttle sensor 72 ... Engine rotation speed sensor 73 ... Input shaft rotation sensor 74 ... Counter shaft sensor 74 ... Counter shaft rotation sensor 75 ... Operation position sensor 76 ... Shift operation lever 77 ... Brake sensor 78 ... Brake pedal 79 ... Laser radar

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Claims (6)

[Claims] 1. A hydraulic power transmission means provided in a power transmission path from an internal combustion engine of a vehicle to drive wheels, and a lockup for adjusting a coupling state between an input shaft and an output shaft of the hydraulic power transmission means. A clutch; a throttle opening detecting means for detecting a throttle opening of the internal combustion engine; and a lock-up when the throttle opening detected by the throttle opening detecting means during traveling of the vehicle becomes a predetermined value or less. A slip control device for a vehicle lock-up clutch, comprising: a slip control unit that controls a clutch to adjust the connection state to a direct connection side; and an obstacle that detects an obstacle existing in a traveling direction of the vehicle. Detecting means for detecting slippage when the obstacle detecting means does not detect an obstacle, or when the obstacle is detected but the distance to the obstacle is a predetermined distance or more. A slip control device for a lock-up clutch for a vehicle, comprising: a suppression means for suppressing the control of the control means. 2. A hydraulic power transmission means provided in a power transmission path from an internal combustion engine of a vehicle to driving wheels, and a lockup for adjusting a coupling state between an input shaft and an output shaft of the hydraulic power transmission means. A clutch; a throttle opening detecting means for detecting a throttle opening of the internal combustion engine; and a lock-up when the throttle opening detected by the throttle opening detecting means during traveling of the vehicle becomes a predetermined value or less. A slip control device for a vehicle lock-up clutch, comprising: a slip control device that controls a clutch to adjust the coupling state to a direct coupling side; and a brake operation detection device that detects an operation state of a brake of the vehicle. Suppressing means for suppressing the control of the slip control means when the brake operation detecting means does not detect that the brake is operated. A slip control device for a lock-up clutch for a vehicle, comprising: 3. An obstacle detecting means for detecting an obstacle existing in a traveling direction of the vehicle, wherein the suppressing means detects when the obstacle detecting means does not detect an obstacle or detects the obstacle. The control of the slip control means is suppressed only when the distance to the obstacle is equal to or longer than a predetermined distance even if the vehicle is in the middle of the vehicle.
A slip control device for a lock-up clutch for a vehicle according to the above. 4. The control device according to claim 1, wherein the control unit suppresses the control of the slip control unit only when a change rate of the throttle opening detected by the throttle opening detection unit is equal to or less than a predetermined value. Item 4. The slip control device for a vehicle lockup clutch according to any one of Items 1 to 3. 5. A vehicle speed detecting means for detecting a vehicle speed of the vehicle, wherein the suppressing means controls the slip control means only when the vehicle speed detected by the vehicle speed detecting means is within a predetermined range. The slip control device for a lock-up clutch for a vehicle according to any one of claims 1 to 4, wherein the slip control is performed. 6. An acceleration detecting means for detecting an acceleration of the vehicle, wherein the control means controls the slip control means only when the acceleration detected by the acceleration detecting means is within a predetermined range. The slip control device for a lock-up clutch for a vehicle according to any one of claims 1 to 5, wherein the slip control is performed.