JPH0828688A - Slip control device of lock-up clutch for vehicle - Google Patents

Abstract

PURPOSE:To suppress damages of the durability of friction material of a lock-up clutch, the working fluid in a torque converter, parts made of resin, or the like attributable to the slip control of the deceleration. CONSTITUTION:When a judgement is made that the fuel cut operation of a fuel cut device 198 is possible by a fuel cut possibility judging means 200 even when a lock-up clutch 32 is not engaged, the starting of the slip control by a slip control means 196 is prevented irrespective of the deceleration of a vehicle by a lip control starting preventing means 202. This constitution eliminates the deterioration of a friction material, the working fluid in a torque converter, the parts made of resin, or the like attributable to the heat generation associated with the unnecessary slip engagement of the lock-up clutch 32 especially during the traveling at a high speed, and the durability of these items is not damaged.

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 a vehicle lock-up clutch.

[0002]

2. Description of the Related Art In a vehicle equipped with a hydraulic transmission with a lock-up clutch such as a torque converter with a lock-up clutch or a fluid coupling with a lock-up clutch, the rotation loss of the lock-up clutch during acceleration is further reduced. For the purpose of improving the fuel efficiency of the vehicle by reducing the number of the lockup clutches, a slip area is provided between the release area and the engagement area of the lockup clutch, and the lockup clutch is actually put in the half engagement state in the slip area. It has been proposed to execute slip control so that the slip amount, that is, the difference between the rotation speed of the pump impeller and the rotation speed of the turbine impeller follows a predetermined target slip rotation speed. Further, in a vehicle equipped with a fuel cut device that shuts off fuel for the engine in a region where the engine rotation speed is higher than a preset fuel cut rotation speed during deceleration travel, the engine rotation speed is also reduced during the deceleration travel. It has been proposed to carry out a slip control similar to the one described above in order to raise and widen the fuel cut range.

By the way, the slip control at the time of deceleration is executed while the deceleration running state of the vehicle is judged based on the detection of the throttle valve opening being in the fully closed state by the idle switch. At the same time, the fuel cutoff operation is ended when the fuel cutoff operation is completed. As a result, the engine rotation speed is raised to a value lower than the turbine impeller rotation speed by a predetermined target slip rotation speed, so that the period during which the engine rotation speed falls to the preset fuel cut rotation speed is expanded and fuel consumption is improved. It will be improved. For example, this is the device described in Japanese Patent Laid-Open No. 1-279157.

[0004]

However, in the above-mentioned conventional slip control device, if the slip control is continued in a certain running state, the durability of the lockup clutch is impaired or the engine speed is suddenly increased. There was a drawback that drivability was impaired by such changes. For example, since the slip control is configured to be executed while the idle switch is in the ON state, the friction material, the hydraulic oil in the torque converter, and the like due to unnecessary slip of the lockup clutch during high-speed traveling, There is a defect that deterioration of resin parts and the like is promoted and their durability is impaired. Also, in slip control during deceleration running, which is performed by returning the accelerator pedal after acceleration running with the lockup clutch released, slippage of the lockup clutch occurs when the torque converter is switched from forward drive to reverse drive. Since the engagement is started, in such an initial condition, the response delay becomes large, or the relationship of the slip amount with respect to the change in the clutch pressing hydraulic pressure becomes unstable, so that the target slip rotation speed is gently achieved. It is difficult to do so, and the slip amount becomes small with a rapid change, and there is a drawback that drivability is impaired.

The present invention has been made in view of the above circumstances, and an object of the present invention is to inconvenience caused by continuing slip control in a specific traveling state, that is, slip in deceleration traveling. Due to the control, the durability of the friction material of the lockup clutch, the hydraulic oil in the torque converter, the resin parts, etc. is impaired, or the drivability is impaired by the operation such as the start of slip control during deceleration traveling. It is an object of the present invention to provide a slip control device for a vehicle lock-up clutch that does not occur.

[0006]

To achieve the above object, the gist of the present invention is to provide a lock-up clutch provided between a pump impeller and a turbine impeller, and a deceleration. In a vehicle having a fuel cut device that shuts off fuel to the engine in a region where the engine rotation speed is higher than a preset fuel cut rotation speed during traveling, the slip rotation speed of the lockup clutch is reduced when the vehicle is decelerated. A slip control device for a vehicle lock-up clutch, comprising a slip control means for controlling so as to match a predetermined target slip rotation speed, (a) engaging the lock-up clutch during deceleration travel of the vehicle, That is, the fuel cutoff operation of the fuel cut device can be performed without slip engagement or full engagement. By the fuel cut possibility determination means for determining whether or not the fuel cut device is in such a state, (b) the fuel cut possibility determination means enables the fuel cutoff operation of the fuel cut device without engaging the lockup clutch. When it is determined that the vehicle is in the state, it includes slip control start blocking means for blocking the start of the slip control by the slip control means irrespective of the deceleration of the vehicle.

[0007]

With this configuration, the fuel cutoff determination means allows the fuel cutoff operation of the fuel cut device without the lockup clutch being engaged, that is, without the slip engagement or the complete engagement. If it is determined that the slip control start prevention means prevents the slip control means from starting the slip control regardless of the deceleration of the vehicle.

[0008]

As described above, the state in which the fuel cutoff operation of the fuel cut device can be performed without engaging the lockup clutch, that is, the slip engagement or the complete engagement,
In other words, the unnecessary slip engagement of the lockup clutch is eliminated within the range where the slip control for raising the engine speed above the fuel cut speed is not originally required. The deterioration of the friction material, the hydraulic oil in the torque converter, the resin parts, and the like due to the above is eliminated, and their durability is not impaired. Then, when the fuel cutoff operation of the fuel cut device is not possible without engaging the lockup clutch, slip control can be started, so the fuel cut range is expanded, and the effect of slip control during deceleration is improved. Can enjoy.

Preferably, the fuel cut possibility determination means decelerates the vehicle based on whether or not the rotational speed of the turbine impeller or the vehicle speed exceeds a preset determination reference value. It is determined whether or not the fuel cutoff operation of the fuel cut device can be performed without engaging the lockup clutch during traveling. This judgment reference value is a value higher than the rotation speed or vehicle speed of the turbine impeller corresponding to the fuel cut rotation speed that is the operating condition of the fuel cut device, for example, a small margin value to the value corresponding to the fuel cut rotation speed or vehicle speed. It is set to the added value. For example, assuming that the fuel cut rotation speed corresponds to a vehicle speed of 60 km / h, the above judgment reference value is set to a value corresponding to the fuel cut rotation speed such as a value corresponding to a vehicle speed of 70 km / h. To be done.

Also, preferably, when the deceleration state in which the start of the slip control by the slip control means is once blocked by the slip control start blocking means is continued,
After that, by the fuel cut possibility determination means,
Even if it is determined that the fuel cutoff operation of the fuel cut device is not possible without engaging the lockup clutch, the slip control prohibition means continuously prohibits the slip control until the next accelerator operation is performed. Is further included. Generally, in slip control during deceleration, the transmission torque of the lock-up clutch is small, and the correspondence relationship between the slip rotation speed and the change in the pressing hydraulic pressure of the lock-up clutch is unstable. The slip rotation speed drastically decreases and the engine rotation speed sharply rises when making the adjustment, which may impair drivability.However, if the above is done, the lockup clutch will continue to operate during deceleration running. Since the slip engagement is not started, the above inconvenience is solved.

Further, preferably, a slip control permission means for permitting the start of the slip control by the slip control means only within a preset period from the time when the decelerating traveling state of the vehicle is detected is further included. With this configuration, even if the fuel cut possibility determination means determines that the fuel cutoff operation of the fuel cut device is not possible without engaging the lockup clutch, the vehicle deceleration is performed. Since the start of slip control is permitted only within a preset period from the time when the running state is detected, before the engine rotational speed falls far below the turbine impeller rotational speed, that is, before the control deviation increases. Since the slip engagement of the lockup clutch is started, there is an advantage that the slip control is stably started.

[0012]

A second aspect of the present invention for achieving the above object is to provide a lock-up clutch provided between a pump impeller and a turbine impeller, and a deceleration traveling mode. In a vehicle having a fuel cut device that shuts off fuel to the engine in a region where the engine rotation speed is higher than a preset fuel cut rotation speed, a slip rotation speed of the lock-up clutch is predetermined when the vehicle is decelerated. A slip control device for a vehicle lock-up clutch, comprising a slip control means for controlling so as to match the target slip rotation speed of the vehicle, wherein the engine rotation speed is lower than the target rotation speed with respect to the target slip rotation speed. When the actual slip rotation speed control deviation exceeds a predetermined judgment reference value Is to include a slip control stop means for stopping the slip control by the slip control means.

[0013]

With this configuration, the slip control stopping means causes the control deviation of the actual slip rotation speed on the side where the engine rotation speed becomes lower than the target rotation speed with respect to the target slip rotation speed to be a predetermined judgment criterion. When the value exceeds the value, the slip control by the slip control means is stopped.

[0014]

As described above, the control deviation of the actual slip rotation speed on the side where the engine rotation speed becomes lower than the target rotation speed with respect to the target slip rotation speed exceeds the predetermined judgment reference value. Indicates that the engine rotation speed is much lower than the turbine impeller rotation speed.Therefore, slip control is stopped when the control deviation deviates in this way, and the engine rotation speed rapidly increases. It is preferably prevented that the property is impaired. Such an effect is effective not only when the slip control is started during deceleration, but also when the control deviation becomes large for some reason during the slip control. Further, since the slip control is stopped based on the deviation of the actual slip control, the slip control is stopped accurately. Incidentally, when the drop in the engine speed is judged by the judgment reference value defined by the absolute value, the judgment is not performed until the drop in the engine speed reaches a predetermined value, so that a sufficient effect cannot be obtained.

An embodiment of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a skeleton view of a vehicle power transmission device to which an embodiment of the present invention is applied. In the figure, the power of the engine 10 is transmitted to a differential gear unit and drive wheels (not shown) through a torque converter 12 with a lockup clutch, a stepped automatic transmission 14 including three sets of planetary gear units, and the like. It is like this.

The torque converter 12 is the engine 1
Is connected to the crankshaft 16 of 0 and has a cross section U at the outer peripheral portion.
A pump impeller 18 having a blade that is bent in a letter shape and that generates a flow of hydraulic oil having a directional component toward the engine 10 side, and is fixed to the input shaft 20 of the automatic transmission 14, Has a blade facing the blade of
A turbine impeller 22 that is rotated by receiving oil from the blades of the pump impeller 18, a stator impeller 28 fixed to a housing 26 that is a non-rotating member via a one-way clutch 24, and an axial movement The lock-up clutch 32 is connected to the input shaft 20 via a piston 30 fitted to the hub portion of the turbine impeller 22 so as to be rotatable relative to the shaft.

In the torque converter 12, the oil pressure in the disengagement side oil chamber 33 among the engagement side oil chamber 35 and the disengagement side oil chamber 33 divided by the piston 30 is increased,
When the hydraulic pressure in the engagement-side oil chamber 35 is released, the piston 30 is retracted and the lockup clutch 32 is disengaged. Therefore, the amplification according to the input / output rotation speed ratio of the torque converter 12 is performed. Torque is transmitted at a rate. However, when the oil pressure in the engagement-side oil chamber 35 is increased and the oil pressure in the disengagement-side oil chamber 33 reaches the minimum pressure, the piston 30 is advanced and the lockup clutch 32 causes the pump impeller 1 to move.
Since it is pressed by 8 to be engaged, the input / output members of the torque converter 12, that is, the crankshaft 16 and the input shaft 20 are directly connected.

The automatic transmission 14 has three coaxially arranged parts.
Set of single pinion type planetary gear units 34, 36, 38
And a counter shaft (output shaft) 40 that transmits power between the input shaft 20, an output gear 39 that rotates together with the ring gear of the planetary gear device 38, and a differential gear device (not shown). Some of the components of their planetary gear 34, 36, 38 is not only integrally connected to each other, are selectively connected to each other by three clutches _{C 0, C 1, C 2} . In addition, the planetary gear device 34,
Some of the components of 36, 38 include four brakes B ₀ ,
B _1, B _2, B with ₃ is selectively connected to the housing 26 by a further, mutually or housing by the rotation direction of some of the components by the three-way clutches F _0, F _1, F ₂ It is designed to be engaged with 26.

The clutches C ₀ , C ₁ and C ₂ and the brakes B ₀ , B ₁ , B ₂ and B ₃ are provided with, for example, a multi-plate type clutch or one band or two bands having opposite winding directions. 2 is constituted by band brakes and the like, each of which is operated by a hydraulic actuator, and the operation of each of these hydraulic actuators is controlled by an electronic control unit 184 for shifting, which will be shown in FIG. As shown in FIG.
A single shift stage / reverse speed is obtained. In FIG. 2, "1
st ”,“ 2nd ”,“ 3rd ”,“ O / D (overdrive) ”
Represent the first speed gear, the second speed gear, the third speed gear, and the fourth speed gear on the forward side, respectively, and the above gear ratio changes from the first speed gear to the fourth speed gear. It becomes smaller as you go. Since the torque converter 12 and the automatic transmission 14 are configured symmetrically with respect to the axis, the lower side of the rotation axis of the input shaft 20 and the upper side of the rotation axis of the counter shaft 40 are omitted in FIG. Is shown.

FIG. 3 is a diagram for explaining the structure of the vehicle control device. In the figure, a hydraulic control circuit 44 includes a shift control hydraulic control circuit for controlling the gear stage of the automatic transmission 14 and a lockup clutch control hydraulic control for controlling engagement of the lockup clutch 32. And a circuit are provided. As is well known, the hydraulic control circuit for gear shift control includes a first solenoid valve S1 and a second solenoid valve S2 that are turned on and off by a solenoid No. 1 and a solenoid No. 2, respectively. Valve S1
2 and the combination of the operations of the second solenoid valve S2.
As shown in FIG. 5, the clutch and the brake are selectively operated to establish any one of the first to fourth speed gear stages.

The lockup clutch control hydraulic control circuit, as shown in FIG. 4, for example, is a third solenoid valve S3 which is turned on / off by a solenoid 48 to generate a switching signal pressure P _sw , and its switching. A lockup relay valve 52 that can be switched between a disengagement side position where the lockup clutch 32 is disengaged and an engagement side position where the lockup clutch 32 is engaged according to the use signal pressure P _sw.
And a linear solenoid valve SLU for generating a slip control signal pressure P _SLU corresponding to the drive current I _SLU supplied from the shift electronic control unit 184, and a linear solenoid valve S
A lock-up control valve 56 that controls the slip amount of the lock-up clutch 32 by adjusting the pressure difference ΔP between the engagement-side oil chamber 35 and the release-side oil chamber 33 according to the slip control signal pressure P _SLU output from the LU. I have it.

In FIG. 4, a pump 60 for sucking the hydraulic oil, which has flowed back into a tank (not shown), through a strainer 58 and sending it under pressure is rotationally driven by the engine 10. The operating oil pressure fed from the pump 60 is firstly fed to the first type by an overflow type first pressure regulating valve 62.
The pressure is adjusted to the line pressure Pl ₁ . This first
The pressure regulating valve 62 generates a first line pressure Pl ₁ that increases corresponding to the throttle pressure output from a throttle valve opening detection valve (not shown), and outputs it via a first line oil passage 64. The second pressure regulating valve 66 is an overflow type pressure regulating valve, and regulates the hydraulic oil that has flowed out from the first pressure regulating valve 62 based on the throttle pressure, so that the second pressure regulating valve 66 corresponds to the output torque of the engine 10. Generate a line pressure Pl ₂ . The third pressure regulating valve 68 is a pressure reducing valve whose source pressure is the first line pressure Pl ₁ and generates a constant third line pressure Pl ₃ . Further, the manual valve 70 generates the R range pressure P _R when the shift operation lever 174 is in the R range. Then, the OR valve 72 operates at a pressure P that operates the brake B ₂ that is engaged when the second speed gear or higher is reached.
_The higher one of _B2 and the R range pressure P _R is selected and output.

The lock-up relay valve 52 has a release side port 80 communicating with the release side oil chamber 33 and an engagement side oil chamber 35.
An engagement side port 82 communicating with the input side port 84 to which the second line pressure Pl ₂ is supplied, a first discharge port 86 from which hydraulic oil in the engagement side oil chamber 35 is discharged when the lockup clutch 32 is released, The second discharge port 8 from which the hydraulic oil in the release side oil chamber 33 is discharged when the lockup clutch 32 is engaged.
8. A supply port 90 to which a part of the hydraulic oil discharged from the second pressure regulating valve 66 is supplied for cooling during the engagement period of the lockup clutch 32, and a spool valve element 92 for switching the connection state of these ports. A spring 94 for urging the spool valve element 92 toward the off-side position, a plunger 96 arranged so as to be capable of contacting the spring 94 side end portion of the spool valve element 92, and the spool valve element 92 and the plunger. 96, an oil chamber 98 provided between the end surface of the plunger 96 and the plunger 9 for applying the R range pressure P _R
The oil chamber 100 that receives the first line pressure Pl ₁ that acts on the end surface of 6 and the third solenoid valve S3 on the end surface of the spool valve element 92.
It reacted with switching signal pressure P _sw since and an oil chamber 102 for receiving the switching signal pressure P _sw to generate a thrust directed to the on-side position.

In the non-excited state (OFF state), the third solenoid valve S3 has its spherical valve block the communication between the oil chamber 102 and the OR valve 72 and makes the oil chamber 102 a drain pressure. In the ON state), the oil chamber 102 and the OR valve 72 are made to communicate with each other, and the switching signal pressure P _sw is applied to the oil chamber 102. Therefore, when the third solenoid valve S3 is in the off state, the switching signal pressure P _sw from the third solenoid valve S3 is not applied to the oil chamber 102, and the spool valve element 92 acts as the biasing force of the spring 94. The input port 84 and the release side port 80 are made to communicate with each other, and the engagement side port 82 and the first discharge port 86 are made to communicate with each other because they are located at the off-side position according to the first line pressure Pl ₁ acting on the oil chamber 100. Therefore, the oil pressure P _off in the disengagement side oil chamber 33 is made higher than the oil pressure P _on in the engagement side oil chamber 35 to release the lockup clutch 32, and at the same time, the hydraulic oil in the engagement side oil chamber 35 is released. Is discharged to the drain through the first discharge port 86, the oil cooler 104, and the check valve 106.

On the other hand, when the third solenoid valve S3 is in the ON state, the switching signal pressure P _sw from the third solenoid valve S3 is applied to the oil chamber 102, and the spool valve element 92 biases the spring 94. And the first line pressure P acting on the oil chamber 100
The input port 84 and the engagement side port 82, the release side port 80 and the second discharge port 88, and the supply port 90 and the first discharge port 86 communicate with each other because they are located at the ON side position against L _1. Therefore, the oil pressure P _on in the engagement side oil chamber 35 is made higher than the oil pressure P _off in the disengagement side oil chamber 33 to engage the lockup clutch 32, and at the same time the disengagement side oil chamber 33 The hydraulic oil is the second discharge port 8 described above.
8 and the lock-up control valve 56 to the drain.

The linear solenoid valve SLU is a pressure reducing valve whose source pressure is a constant third line pressure Pl ₃ generated by the third pressure regulating valve 68, and as shown in FIG. The slip control signal pressure P _SLU that increases with the drive current I _SLU (that is, the drive duty ratio DSLU) from is generated, and this slip control signal pressure P _{SLU is applied} to the lockup control valve 56. The linear solenoid valve SLU includes a supply port 110 to which the third line pressure Pl ₃ is supplied, an output port 112 for outputting a slip control signal pressure P _SLU , a spool valve 114 for opening and closing them, and a spool valve 114 thereof. A spring 115 for urging the spool valve 114 in the valve opening direction, a spring 116 for urging the spool valve 114 in the valve opening direction with a smaller thrust than the spring 115, and a spool valve 114 for the valve opening direction according to the drive current I _SLU . An electromagnetic solenoid 118 for biasing the slip control and an oil chamber 120 for receiving a feedback pressure (a signal pressure P _SLU for slip control) for generating thrust in the valve closing direction in the spool valve 114 are provided. 114 is an electromagnetic solenoid 1
The biasing force of the valve 18 and the spring 116 in the valve opening direction and the biasing force of the spring 115 and the feedback pressure in the valve closing direction are balanced.

The lockup control valve 56 is
Second line pressure Pl₂Is supplied to the line pressure port 130,
Release-side oil chamber 33 discharged from the second discharge port 88
Receiving port 132 for receiving the hydraulic oil in the
For discharging the hydraulic oil received in the port 132.
Len port 134, receiving port 132 and drain port
And the hydraulic oil in the release side oil chamber 33 is communicated.
The engagement side oil chamber 35 and the release side oil chamber can be discharged.
33 pressure difference ΔP (= P_on−P_off) Increase first
Toward the position (left side position in FIG. 4) and the receiving port 13
2 and the line pressure port 130 communicate with each other to release the oil on the release side.
In the chamber 33, the second line pressure Pl₂By supplying
Toward the second position (right side position in FIG. 4) that decreases ΔP
Spool valve 13 provided to be movable in the direction
6 and its spool valve element 136 toward the first position.
Arranged so that it can abut against its spool valve 136 for biasing
The plunger 138 and the plunger 138
Lip control signal pressure P_SLUTo move to the first position
Slip control signal pressure P to generate thrust _SLU
To the signal pressure oil chamber 140 and the plunger 138
Oil pressure P in the release side oil chamber 33_offAct on the plunger
138 with spool valve 136 towards its first position
Its hydraulic pressure P in order to generate thrust in the opposite direction_offAccept
Oil chamber 142 that engages with the spool valve element 136.
Oil pressure P in_onThe spool valve element 136 to
The hydraulic pressure P to generate thrust in the direction toward the 2 position_on
And an oil chamber 144 that receives
The spool valve 136 toward the second position.
And a biasing spring 146.

Here, the plunger 138 has an oil chamber.
Cross-sectional area A that increases from the 142 side₁ And A₂ Have
To form the first land 148 and the second land 150.
The spool valve 136 has a signal pressure oil chamber.
Cross-sectional area A from 140 side₃ The third land 152, and
And above cross-sectional area A₁ 4th land 154 having the same cross-sectional area as
Are formed. Therefore, the plunger 138 is
It abuts the pool valve 136 and operates integrally with each other.
Slip control signal pressure P on both sides of the stone 30_{SL U}Corresponding to
Pressure difference ΔP (= P_on−P_off) Is formed
It At this time, the pressure difference ΔP is the slip control signal pressure P.
_SLUTo the slope [(A₂ -A₁ ) / A
₁ ] As shown in FIG. In addition, Formula 1
At F _sIs the urging force of the spring 146.

[0030]

[Equation 1]

FIG. 6 shows a change characteristic of the pressure difference ΔP obtained by the operation of the lockup control valve 56 constructed as described above with respect to the slip control signal pressure P _SLU . Therefore, the lockup relay valve 52
Is on, the slip control signal pressure P _SLU
The engagement side oil chamber 35 and the release side oil chamber 33
Since the pressure difference ΔP (= P _on -P _off ) with
Slip rotation speed NSLP of the lockup clutch 32
However, on the contrary, the slip control signal pressure P
_{When the SLU} becomes lower, the slip rotation speed NSLP is increased.

Returning to FIG. 3, the vehicle has an engine rotation speed sensor 160 for detecting the rotation speed N _E of the engine 10, that is, the rotation speed N _P of the pump impeller 18, intake air drawn into the engine 10 through the intake pipe. The intake air amount sensor 162 for detecting the amount Q, the engine 1 through the intake pipe
A throttle sensor 1 with an idle switch for detecting a fully closed state and an opening θ ₁ of a throttle valve 166 which is opened / closed by operating an accelerator pedal 165 and an intake air temperature sensor 164 which detects a temperature T _{AIR of} intake air sucked to 0.
67, a vehicle speed sensor 168 that detects the rotational speed of the output shaft of the automatic transmission 14, that is, the vehicle speed V, a cooling water temperature sensor 170 that detects the cooling water temperature T _WA of the engine 10, and a brake sensor 172 that detects that the brake pedal has been operated. ,
The operation position P _s of the shift operation lever 174, that is, L,
An operation position sensor 176 for detecting any one of S, D, N, R, and P ranges, and a rotation speed N of the turbine impeller 22.
_T, that is, the turbine rotation speed sensor 178 that detects the rotation speed of the input shaft 20 of the automatic transmission 14, the hydraulic control circuit 4
An oil temperature sensor 180 for detecting the temperature T _OIL of hydraulic oil _No. 4 is provided. The signals output from the above sensors are directly or indirectly supplied to the electronic control unit 182 for the engine and the electronic control unit 184 for the shift. The electronic control unit 182 for the engine and the electronic control unit 184 for shifting are interconnected via a communication interface, and input signals and the like are supplied to each other as necessary.

The electronic control unit 184 for shifting is a CPU, R
The CPU is a so-called microcomputer including an OM, a RAM, an interface, etc., and its CPU uses the temporary storage function of the RAM to process an input signal in accordance with a program stored in advance in the ROM, and controls the shift of the automatic transmission 14 and The engagement control of the lockup clutch 32 is executed according to a main routine (not shown), and the first solenoid valve S
The first solenoid valve S2, the third solenoid valve S3, and the linear solenoid valve SLU are controlled.

In the above shift control, it is stored in the ROM in advance.
Corresponding to the actual shift gear stage from multiple types of shift diagrams
A shift diagram is selected, and the running condition of the vehicle is selected from the shift diagram.
State, for example, throttle valve opening θ₁And the vehicle speed V
The shift gear is determined by the
Driving the first solenoid valve S1 and the second solenoid valve S2
Allows the clutch C of the automatic transmission 14 to₀ , C₁ , C₂ ,
And brake B₀ , B ₁ , B₂ , B₃ Operation is controlled
And one of the four forward gears is established.
It

The engagement control of the lock-up clutch 32 is executed during traveling in, for example, the third speed gear stage and the fourth speed gear stage, and in the engagement control during acceleration travel, From the relationship shown in FIG. 7 stored in advance in the ROM, the running state of the vehicle, such as the output shaft rotation speed (vehicle speed)
Based on N _out and the throttle valve opening degree TAP, it is determined whether the lock-up clutch 32 is in the disengagement region, the slip control region, or the engagement region. In this slip control region, the lockup clutch 32 is maintained in a slip state so that the lockup clutch 32 is coupled while absorbing torque fluctuations of the engine 10 for the purpose of improving fuel economy as much as possible without impairing drivability. Even during deceleration coasting of the vehicle, slip control of the lockup clutch 32 is executed for the purpose of expanding the control range of the fuel cut control. In this case, since the throttle valve opening TAP is zero and the vehicle is coasting, the slip region specified by the vehicle speed V is used exclusively.

When it is determined that the running state of the vehicle is within the engagement region, the third solenoid valve S3 is excited and the lockup relay valve 52 is turned on, and at the same time the linear solenoid valve SLU is driven. Since the current I _SLU is set to the minimum drive current (rated value), the lockup clutch 32 is completely engaged. When it is determined that the traveling state of the vehicle is within the release area, the third solenoid valve S3
Is de-excited and the lockup relay valve 52 is turned off, so that the lockup clutch 32 is released regardless of the drive current I _SLU for the linear solenoid valve SLU. When it is determined that the running state of the vehicle is within the slip control range, the third solenoid valve S3 is excited and the lockup relay valve 52 is turned on, and at the same time, the drive current for the linear solenoid valve SLU is increased. I
_{The SLU} is adjusted according to Equation 2, for example. That is,
For example, the deviation ΔE between the target slip rotation speed TNSLP and the actual slip rotation speed NSLP (= N _E −N _T ).
The drive current I _SLU, that is, the drive duty ratio DSLU, is calculated and output so that (= NSLP-TNSLP) is eliminated.

[0037]

[Equation 2]

DFWD on the right side of the above equation 2 is, for example, a feedforward value which is a function of the output torque of the engine 10, and KGD is a learning control value formed corresponding to the characteristics of each machine, and DFB. Is a feedback control value obtained by adding a proportional value, a differential value, and an integral value of the deviation ΔE as shown in Equation 3, for example.

[0039]

(Equation 3)

Further, an electronic control unit 182 for the engine
Is a microcomputer similar to the electronic control unit 184 for gear shifting, and its CPU executes various engine controls by processing an input signal according to a program stored in ROM in advance. For example, in the fuel injection amount control, the fuel injection valve 186 is controlled to optimize the combustion state, in the ignition timing control, the igniter 188 is controlled to adjust the retard amount appropriately, and in the traction control, the drive wheels of the drive wheels are controlled. In order to prevent slip and ensure effective driving force and vehicle stability, the throttle actuator 190
The second throttle valve 192 that is normally fully open is controlled by the.
In coasting in which it is detected that the throttle valve 166 has been closed by the idle switch of No. 7, the fuel injection valve 186 is closed for a period in which the engine rotation speed N _E exceeds the preset fuel cut rotation speed N _CUT. As a result, the fuel supplied to the engine 10 is shut off to improve fuel efficiency. In this embodiment, the electronic control unit 182 for the engine and the fuel injection valve 186 correspond to the fuel cut unit 198 described later.

FIG. 8 is a functional block diagram for explaining a main part of the control function of the electronic shift control device 184. In FIG. 8, the slip control means 196 controls the actual slip rotation speed NSLP (= N of the lockup clutch 32).
_E− N _T ) and the target slip rotation speed TNSLP preset to several tens rpm are set so that they are equal to each other by Equation 2
The control value DSLU calculated by the control equation is output.
The fuel cut possibility determination means 200 determines whether or not the fuel cutoff operation of the fuel cut device 198 can be performed without engaging the lockup clutch 32 during deceleration of the vehicle. The slip control start prevention means 202 is the fuel cut possibility determination means 2
If it is determined by 00 that the fuel cutoff operation of the fuel cut device 198 is possible without engaging the lockup clutch 32, the slip control means 196 slips regardless of deceleration of the vehicle. Prevent control from starting.

The slip control permission means 204 is set within a preset period from when the deceleration running state of the vehicle is detected based on the fact that the throttle valve 166 is closed by the idle switch of the throttle sensor 167. Only the start of the slip control by the slip control means 196 is permitted. This is because slip engagement of the lockup clutch is started at the moment when the idle switch is turned on or in a state close to this, so that slip control is stably started. The slip control prohibiting means 206 engages the lockup clutch 32 by the fuel cut possibility determining means 200 when the deceleration state in which the start of the slip control by the slip control means 196 is once stopped by the slip control start preventing means 202 continues. Even if it is determined that the fuel cutoff operation of the fuel cut device 198 is not possible even if they do not match, the slip control is continuously prohibited until the next accelerator operation. Then, the slip control stop means 208 controls the actual slip rotation speed NSLP on the side where the engine rotation speed N _E becomes lower than the turbine rotation speed N _{T with} respect to the target slip rotation speed TNSLP.
However, if it exceeds the predetermined determination reference value DNSLP1, the slip control by the slip control means 196 is stopped. The control deviation ΔE (DNSLPK) is calculated by the deviation calculating means 210.

The main part of the control operation of the electronic control unit 184 for shifting will be described below with reference to the flowchart of FIG.

In FIG. 9, in step SJ1 (hereinafter, step is omitted) corresponding to the deceleration running detection means,
It is determined whether or not the idle switch of the throttle sensor 167 is in the on state, that is, whether or not the deceleration traveling with the throttle valve 166 fully closed is detected. This S
If the determination in J1 is negative, it means that the vehicle is not in decelerating mode, so the slip control during decelerating mode is stopped in SJ9.

However, if the determination in SJ1 is affirmative, the vehicle is decelerating, and therefore it is determined in SJ2 whether or not slip control is being performed during decelerating traveling. Since initially the determination in SJ2 is negative, the in slip control permitting means 204 and slip control prohibition unit 206 corresponding to the SJ3, within the criterion value T ₁ that the elapsed time has been set in advance from the idle switch ON state Is determined. This judgment reference value T ₁ is shown in FIG.
The value is set to a value that is larger than the cycle of the slip control cycle and does not cause a shock due to the start of slip control during deceleration, for example, a value of about 20 ms to 200 ms.

When the judgment of SJ3 is denied, SJ
Although the slip control is stopped in S9, if the result is affirmative, it is determined in SJ4 that follows whether or not the slip control start condition is satisfied. This slip control start condition includes slip rotation speed NSLP (= N _E −N _T ).
Is greater than or equal to a predetermined start determination reference value, for example, −50 rpm.

When the above judgment of SJ4 is denied, SJ
In S9, the slip control is stopped, but when the result is affirmative, the vehicle speed V is equal to or lower than the predetermined judgment reference value C in SJ5 corresponding to the fuel cut possibility judgment means 200 and the slip control start prevention means 202. It is determined whether or not. The determination reference value C is set to a value higher than the vehicle speed corresponding to the fuel cut rotation speed N _CUT by a predetermined margin value. For example, if the vehicle speed corresponding to the fuel cut rotation speed N _CUT is 60 km / h, it is set to about 70 km / h.

If the determination in SJ5 is negative, S
Despite the fact that the slip control start conditions at the time of deceleration running in J3 and SJ4 are satisfied, respectively, SJ6
Execution of the slip control at the time of decelerating traveling is prevented from starting the execution of the slip control of SJ8.
As a result, the slip control, which is essentially unnecessary, is not executed during high-speed traveling, so the lock-up clutch 32
Various inconveniences caused by the heat generation due to the slip engagement are eliminated.

However, while the above steps are repeatedly executed during the deceleration traveling, the accelerator pedal 16
When the idle switch is turned on and the vehicle speed V falls below the judgment reference value C by re-operation of 5, the judgments of SJ4 and SJ5 are affirmed, and the slip control means 19
In SJ6 corresponding to 6, slip control at the time of decelerating traveling is started. That is, the target slip rotation speed TNS
LP and actual slip rotation speed NSLP (= N _E −
N _T) the difference between the DNSLPK (= NSLP-TNSL
P) is solved, the deviation DNS
The drive current I _SLU, that is, the drive duty ratio DSLU, is calculated and output based on the LPK, the output torque of the engine 10, and the like.

As described above, slip control during deceleration travel
Control is started, the SJ2 of the next control cycle
Since the determination is positive, the deviation calculating means 210 and
In SJ7 corresponding to the slip control stopping means 208
The control deviation DNSLPK is calculated and the control is performed.
Deviation DNSLPK (= ΔE) is a preset judgment criterion
It is determined whether the value is larger than the value DNSLP1. this
The determination reference value DNSLP1 is the target slip rotation speed TN.
The difference between the SLP and the actual slip rotation speed NSLP,
Engine speed N in the slip control_EThe tar
Bin rotation speed N _TIs the feedback system
The engine speed N is rapidly increased by the operation._EIs rising
To determine that it is large enough to affect drivability
It is the set value.

If the determination in SJ7 is affirmative, the slip control during deceleration travel is stopped in SJ9. However, if the judgment of SJ7 is denied, SJ7
At 8, it is determined whether or not other slip control termination conditions are satisfied. Other slip control termination conditions include:
Slip speed NSLP (= N _E -N _T) is included that is predetermined start determination reference value, for example, -100r.pm more. Even if the judgment of SJ8 is denied, SJ6
The slip control of No. 2 is continued, but if the determination of SJ8 is affirmative, the slip control is stopped at SJ9.

As described above, according to this embodiment, the fuel cutoff operation of the fuel cut device 198 can be performed without engaging the lockup clutch 32 by the SJ5 corresponding to the fuel cut possibility determination means 200. If it is determined that the slip control start prevention means 202 prevents the slip control means 196 from starting the slip control regardless of the deceleration of the vehicle. Therefore, the friction material, the hydraulic oil in the torque converter, which is caused by the heat generated by the unnecessary slip engagement of the lock-up clutch 32 during high-speed traveling,
Deterioration of resin parts, etc. is eliminated and their durability is not impaired.

Further, in this embodiment, the slip control permission hand is
Corresponding to the step 204 and the slip control prohibiting means 206
SJ3 detects the deceleration running state of the vehicle by SJ1
The preset period T from when₁Only slip inside
The start of slip control by the control means 196 is permitted.
It Therefore, once the period T₁When the
Slip control is started until the cell pedal is operated again.
Therefore, the drivability is not impaired. By the way,
As shown in FIG. 11, as the deceleration travel starts
If the slip control is started after the
Engine rotation speed N _EIs the turbine wheel speed N_Tthan
The feedback starts when it goes down greatly.
And the predetermined response delay time T_DAbruptly after
Rotation speed N_EMay rise and impair drivability.
It was.

Further, in the present embodiment, the actual slip on the side where the engine speed N _E becomes lower than the turbine impeller speed N _T with respect to the target slip speed TNSLP by the SJ7 corresponding to the slip control stopping means 208. When the control deviation DNSLPK of the rotation speed NSLP exceeds the predetermined determination reference value DNSLP1, the slip control by the slip control means 196 is stopped. Therefore, as shown in FIG. 12, when the engine rotational speed N _E is significantly lower than the turbine impeller rotational speed N _T , the feedback control operation causes the engine rotational speed N _E to rapidly increase, thereby operating the engine. It is preferably prevented that the property is impaired. Such an effect is effective not only when the slip control is started during deceleration, but also when the control deviation becomes large for some reason even during the slip control. Further, according to the present embodiment, the slip control is stopped based on the actual control deviation DNSLPK, so that the slip control is accurately stopped. Incidentally, the engine speed N
_When the drop of _E is judged by the judgment standard value defined by the absolute value, the judgment is not performed until the judgment standard value is reached, and therefore the effect was not sufficiently obtained.

Next, another embodiment of the present invention will be described. In the following embodiments, the same reference numerals are given to portions common to the above description, and the description will be omitted.

SJ3 may be eliminated in the embodiment of FIG. In this embodiment, when the vehicle speed V exceeds the judgment reference value C, the slip control, which is essentially unnecessary for high-speed traveling, is not executed in the same manner as in the above-described embodiments, so that the lock-up clutch 32 is slip-engaged. Various inconveniences caused by heat generation are eliminated, and the lockup clutch 3
When the fuel cut-off operation of the fuel cut device 198 is not possible (vehicle speed V ≦ C) without engaging No. 2, slip control is started, so that the engine rotation speed N _{E as} shown by the solid line in FIG. Changes. Therefore, the fuel cut range is expanded from the fuel cut range in the case of the one-dot chain line where slip control is not performed, and the fuel consumption improvement effect of slip control during deceleration can be enjoyed. Further, as compared with the case indicated by the chain double-dashed line in which the slip control is performed in the entire deceleration traveling, the slip control is not performed in the high speed range, so that heat generation is suppressed.

Next, FIG. 13 is a flow chart showing another control operation of the electronic control unit 184 for shifting, which is similar to that shown in FIG. 9, so that the differences will be mainly described below. To do.

When it is determined in SJ1 of FIG. 13 that the idle switch is not in the ON state, the content of the flag XF is cleared to "0" in SJ10. The flag XF, when the content is "1", indicates that the slip control start condition at the time of deceleration traveling is not satisfied in SJ2 and SJ3. This SJ1
If the determination is positive, it is determined in SJ11 whether the content of the flag XF is "1". This S
J11 corresponds to the slip control permission means 204 and the slip control prohibition means 206. That is, when the content of the flag XF is set to "1" by the SJ11, the slip control is kept stopped unless the idle switch is turned off again. The content of the flag XF is set to "1" when the determinations of SJ3 and SJ5 are denied when the idle switch is turned on. Conversely, when the idle switch is on, SJ
If S3 and SJ5 are satisfied, it is the period before the content of the flag XF is set to "1", and therefore the determination of SJ11 is denied and the slip control is permitted.

SJ4: slip rotation speed NSLP
(= N _E −N _T ) is a predetermined start determination reference value, for example −5.
If the slip control start condition at the time of deceleration traveling including 0 rpm or more is denied, or if it is determined in SJ5 that the vehicle speed V is equal to or higher than the determination reference value C, S
After the content of the flag XF is set to "1" in J12, the slip control is stopped in SJ9. Therefore, in the next control cycle, the determination of SJ11 is affirmative, so that the slip control of SJ9 is continuously stopped until the accelerator pedal is next turned on.

According to this embodiment, in addition to the same effect as that of the above-described embodiment, the start of the slip control by the slip control means is once blocked by the SJ7 corresponding to the slip control start blocking means 202. When the deceleration state continues, the content of the flag XF is set to "1", and thereafter, the fuel cut is performed by the SJ5 corresponding to the fuel cut possibility determination means 200 without engaging the lockup clutch 32. Even if it is determined that the fuel cutoff operation of the device 198 is not possible, the slip control is continuously prohibited by the SJ11 corresponding to the slip control prohibiting means 206 until the next accelerator pedal operation is performed. . In general, in slip control during decelerating traveling, the transmission torque of the lockup clutch 32 is small, and the correspondence relationship between the slip rotation speed and the change in the pressing hydraulic pressure of the lockup clutch 32 is unstable. Lockup clutch 3
When slip engagement is performed from the release state of No. 2, the slip rotation speed NSLP sharply decreases and the engine rotation speed N _E sharply increases, so the drivability may be impaired. By doing so, the slip engagement of the lock-up clutch 32 is not started while the deceleration traveling is continued, so that the above-mentioned inconvenience is solved.

Although one embodiment of the present invention has been described above with reference to the drawings, the present invention can be applied to other modes.

For example, in SJ5 of the above-described embodiment, it is determined whether the vehicle speed V is equal to or lower than the preset reference value C, but the turbine rotation speed N _T and the output of the automatic transmission 14 are determined. It may be judged whether or not the shaft rotation speed is equal to or higher than a preset judgment reference value. The criterion value is also set in relation to the fuel cut-off rotation speed N _CUT, a value obtained by adding a predetermined margin value to a value corresponding to the fuel cut-off rotation speed N _CUT is employed.

The SJ11 of the above-mentioned embodiment is SJ1.
Since it is executed after the affirmative determination is made, it is also determined that the deceleration traveling is continued after the content of the flag XF is once set to "1", but the fuel supply is cut off. The deceleration continuation may be determined by being provided in series with the step of determining that the deceleration is being performed.

In the embodiment of FIG. 9 described above, the SJ
It does not matter if 3 and SJ4 are replaced.

The above is merely an embodiment of the present invention, and the present invention can be modified in various ways without departing from the spirit thereof.

[Brief description of drawings]

FIG. 1 is a diagram showing a vehicle power transmission device to which a slip control device according to an embodiment of the present invention is applied.

FIG. 2 is a schematic diagram showing an automatic transmission including the torque converter with a lockup clutch of FIG.
It is a chart explaining the relationship between the combination of the operation of the solenoid valve and the shift speed obtained thereby.

FIG. 3 is a block diagram illustrating a configuration of a control device included in the vehicle of FIG.

FIG. 4 is a diagram illustrating a configuration of a main part of the hydraulic control circuit of FIG.

5 is a diagram showing the output characteristics of the linear solenoid valve of FIG.

6 is a characteristic of a slip control valve provided in the hydraulic control circuit of FIG. 4, illustrating a relationship between a pressure difference ΔP between an engagement oil chamber and a release oil chamber and a slip control signal pressure P _SLU. FIG.

7 is stored in the electronic shift control device of FIG. 3,
It is a figure which shows the relationship between the running state of a vehicle and the engagement state of a lockup clutch.

8 is a functional block diagram illustrating a main part of a control function of the electronic shift control device of FIG.

9 is a flowchart illustrating a main part of a control operation of the electronic shift control device of FIG.

FIG. 10 is a diagram illustrating an operation in which the fuel cut range is expanded by slip control during decelerating traveling, which is executed by the control operation in FIG. 9.

FIG. 11 is a diagram illustrating a phenomenon in which the engine rotation speed N _E suddenly increases when the slip control is started after a considerable amount of time has elapsed since the idle switch was turned on by the control operation of FIG. 9;

FIG. 12 is an engine speed N during slip control.
It is a figure explaining the state where _E decreased and slip rotation speed NSLP increased.

FIG. 13 is a diagram corresponding to FIG. 9 for explaining the control operation of another embodiment of the present invention.

[Explanation of symbols]

 18: Pump impeller 22: Turbine impeller 32: Lock-up clutch 196: Slip control means 198: Fuel cut device 200: Fuel cut possibility determination means 202: Slip control start prevention means 204: Slip control permission means 206: Slip control prohibition Means 208: Slip control stop means 210: Deviation calculation means

Claims (3)

[Claims] 1. A lock-up clutch provided between a pump impeller and a turbine impeller, and a fuel for the engine in a region where the engine rotation speed is higher than a preset fuel cut rotation speed during deceleration traveling. In a vehicle having a fuel cut device for shutting off, a lockup clutch for a vehicle equipped with slip control means for controlling the slip rotation speed of the lockup clutch to match a predetermined target slip rotation speed when the vehicle is decelerated. A slip control device for determining whether or not a fuel cutoff operation of the fuel cut device is possible without engaging the lockup clutch during deceleration of the vehicle. And the lockup by the fuel cut possibility determination means. When it is determined that the fuel cutoff operation of the fuel cut device can be performed without engaging the latch, the slip control means prevents the slip control from being started regardless of the deceleration of the vehicle. A slip control device for a vehicle lock-up clutch, comprising: slip control start prevention means. 2. The lockup clutch is engaged by the fuel cut possibility determination means when the deceleration state in which the start of the slip control by the slip control means is once stopped by the slip control start prevention means is continued. Even if it is determined that the fuel cutoff operation of the fuel cut device is not possible without doing so, it includes a slip control prohibiting means for continuously prohibiting the slip control until the next accelerator operation. 1. A slip control device for a vehicle lock-up clutch. 3. A lock-up clutch provided between a pump impeller and a turbine impeller, and a fuel for the engine in a region where the engine rotation speed during deceleration travel is higher than a preset fuel cut rotation speed. In a vehicle having a fuel cut device for shutting off, a lockup clutch for a vehicle equipped with slip control means for controlling the slip rotation speed of the lockup clutch to match a predetermined target slip rotation speed when the vehicle is decelerated. In the slip control device, when the control deviation of the actual slip rotation speed on the side where the engine rotation speed becomes lower than the target rotation speed with respect to the target slip rotation speed exceeds a predetermined determination reference value, Slip control stopping means for stopping slip control by the slip control means The slip lockup clutch control apparatus for a vehicle, which comprises.