JP2924653B2 - Slip control device for vehicle lock-up clutch - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lock 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 rotational loss of the lock-up clutch during acceleration traveling is further reduced. In order to improve the fuel efficiency of the vehicle by reducing the slip area, a slip area is provided between the release area and the engagement area of the lock-up clutch, and the lock-up clutch is half-engaged in the slip area. It has been proposed to execute the slip control so that the slip amount, that is, the difference between the rotation speed of the pump wheel and the rotation speed of the turbine wheel, follows a predetermined target slip rotation speed. Also, 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 driving, the engine rotation speed is also reduced during deceleration driving. It has been proposed to execute the same slip control as described above in order to increase the fuel cut range by raising it.

[0003] The above-mentioned vehicle includes a lock-up relay valve for supplying hydraulic oil to one of the release-side oil chamber and the engagement-side oil chamber of the lock-up clutch and discharging the hydraulic oil from the other, and a release-side of the lock-up clutch. A lock-up control valve that adjusts the slip amount of the lock-up clutch by adjusting the pressure of hydraulic oil discharged from the oil chamber through the lock-up relay valve, and a control signal pressure for controlling the lock-up control valve. And a linear solenoid valve to be generated. For example, Japanese Unexamined Patent Publication
That is the slip control device described in Japanese Patent Application No. 993311.

[0004]

In the slip control apparatus for a lock-up clutch for a vehicle as described above, when a failure of the lock-up relay valve occurs, the lock-up clutch is engaged even in a region where the lock-up clutch should be released. As a result, the driving performance or the running performance is deteriorated due to the muffled noise of the engine vibration.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a lockup for a vehicle in which drivability or running performance does not decrease regardless of the failure of the lockup relay valve. An object of the present invention is to provide a clutch slip control device.

[0006]

SUMMARY OF THE INVENTION To achieve the above object, the gist of the present invention is to provide a vehicle having a lock-up clutch between a pump impeller and a turbine impeller. a lock-up relay valve for discharging the hydraulic oil from the release side oil chamber and to supply hydraulic fluid to one of the engagement side oil chamber other, the lock-up class
Lock-up switched to the side that engages the switch
A lock-up control valve for adjusting the slip amount of the lock-up clutch by adjusting the pressure of hydraulic oil discharged from the release-side oil chamber through the relay valve, and a slip control device for a vehicle lock-up clutch, (a) a vehicle speed determining means determines whether or not the vehicle speed is equal to or less than a preset determination reference value, (b) the lockup click
In the area where the latch should be released, the vehicle speed determining means determines that the vehicle speed has become equal to or less than the reference value.
Until the lock-up relay valve
Locked on the side to lower the pressure of hydraulic oil discharged through
The up-control valve is switched, but if it is determined that the vehicle speed has become equal to or less than the determination reference value, lock-up is performed to increase the pressure of hydraulic oil discharged from the release-side oil chamber through the lock-up relay valve. Lock-up control valve switching control means for switching the control valve preferentially. Here, preferably,
The lock-up control valve switching control means is
In the state where the high speed gear has been achieved,
Until it is determined that the vehicle speed has fallen below the criteria
Passes through the lock-up relay valve from the release side oil chamber.
Lock-up on the side that lowers the pressure of hydraulic oil
Switch the control valve, but the vehicle speed
If it is determined that the value is equal to or less than the value, the release-side oil chamber
Actuated through the lock-up relay valve
Lock-up control valve on the side that increases oil pressure
Switching. Also preferably, the vehicle is
A step-type transmission, wherein the lock-up control valve
The shift control means operates in a state where the second gear is achieved.
When the vehicle speed is determined by the vehicle speed determination means to be equal to or less than the determination reference value.
Until it is determined that the lock has been
Pressure of the hydraulic oil discharged through the backup relay valve
Switch the lock-up control valve to the lock side
Is determined when the vehicle speed is determined to be equal to or less than the reference value.
In this case, the lock-up relay valve is
Locked on the side to increase the pressure of hydraulic oil discharged through
It switches the up control valve.

[0007]

In this way, when the vehicle speed judging means judges that the vehicle speed has become equal to or less than a predetermined judgment reference value, the lock-up control valve switching control means causes the lock-up control valve switching control means to switch from the release side oil chamber. The lock-up control valve is preferentially switched to the side that increases the pressure of the hydraulic oil discharged through the lock-up relay valve.

[0008]

Therefore, even if the lock-up clutch is to be engaged in a region where the lock-up clutch should be released due to a failure of the lock-up relay valve, if the vehicle speed is equal to or less than a predetermined reference value, the lock-up clutch is not locked. Since the lock-up control valve is preferentially switched to the side where the hydraulic oil discharged from the release-side oil chamber through the relay valve is increased, the differential pressure between the engagement-side oil chamber and the release-side oil chamber of the lock-up clutch is reduced. Since the engagement of the lock-up clutch is substantially eliminated by making it smaller, it is possible to prevent the drivability or the traveling performance from being reduced due to the muffled noise of the engine vibration at the time of low vehicle speed traveling.

Further, according to the present invention, when the vehicle speed is equal to or lower than a predetermined reference value, the lock-up control valve is preferentially switched to the side where the hydraulic oil discharged from the release side oil chamber is increased. Therefore, there is an advantage that it is not necessary to determine the failure of the lock-up relay valve.

[0010] Preferably, the vehicle has a shift range switching means for changing the lowest gear position in the shift range of the automatic transmission when operated by the driver, and the shift range switching means for changing the shift range. A reference value changing means for changing a reference value of the vehicle speed used by the vehicle speed determining means according to the lowest gear position when the lowest gear position is achieved is provided. This has the advantage that the criterion value can be made as low as possible without causing engine stall.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a skeleton diagram of a vehicle power transmission device to which one embodiment of the present invention is applied. In the figure, the power of an engine 10 is transmitted to a differential gear device and drive wheels (not shown) through a torque converter 12 with a lock-up clutch, a stepped automatic transmission 14 composed of three sets of planetary gear units, and the like. It has become.

The above-mentioned torque converter 12 is used for the engine 1
0 at the outer peripheral portion.
A pump impeller 18 having blades for generating a flow of hydraulic oil having a directional component directed toward the engine 10 and being fixed to the input shaft 20 of the automatic transmission 14, Having blades facing the blades of
A turbine wheel 22 that is rotated by receiving oil from the blades of the pump wheel 18, a stator wheel 28 fixed to a housing 26 that is a non-rotating member via a one-way clutch 24, and moves axially. A lock-up clutch 32 connected to the input shaft 20 via a piston 30 fitted to a hub of the turbine wheel 22 so as to be able to rotate relative to the shaft.

In the torque converter 12, the hydraulic pressure in the release-side oil chamber 33 of the engagement-side oil chamber 35 and the release-side oil chamber 33 divided by the piston 30 is increased, and the pressure in the engagement-side oil chamber 35 is increased. Is released, the piston 3
Since 0 is retracted and the lockup clutch 32 is disengaged, torque is transmitted at an amplification factor corresponding to the input / output rotation speed ratio of the torque converter 12. But,
The hydraulic pressure in the engagement-side oil chamber 35 is increased, and the release-side oil chamber 33 is increased.
Is released, the piston 30 is advanced and the lock-up clutch 32 is pressed by the pump impeller 18 to be engaged, so that the torque converter 12
Input / output members, that is, the crankshaft 16 and the input shaft 2
0 is directly connected.

The automatic transmission 14 is provided with a three-axis
Sets of single pinion type planetary gear sets 34, 36, 38
And a counter shaft (output shaft) 40 for transmitting power between an output gear 39 rotating 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} . Further, the planetary gear units 34,
Some of the components of 36, 38 consist of four brakes B ₀ ,
B ₁ , B ₂ , B ₃ are selectively connected to the housing 26 and, in addition, some of the components are connected to one another or to the housing by three one-way clutches F ₀ , F ₁ , F ₂ depending on the direction of rotation. 26.

The clutches C ₀ , C ₁ , C ₂ and the brakes B ₀ , B ₁ , B ₂ , B ₃ include, for example, a multi-plate clutch or one band or two bands whose winding directions are opposite to each other. It is constituted by band brakes and the like, and each is operated by a hydraulic actuator. The operation of each of the hydraulic actuators is controlled by an electronic control unit for shifting 184 described later, whereby the operation shown in FIG. As shown in FIG. 4, the forward speeds 4 having different speed ratios I (= rotation speed of input shaft 20 / rotation speed of counter shaft 40)
A single shift stage / reverse speed is obtained. In FIG. 2, “1”
st "," 2nd "," 3rd "," O / D (overdrive) "
Represents a first gear, a second gear, a third gear, and a fourth gear, respectively, on the forward side, and the above-mentioned gear ratio is changed from the first gear to the fourth gear. It becomes smaller sequentially as it goes. In addition, 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 configuration of the control device of the vehicle. In the figure, a hydraulic control circuit 44 includes a shift control hydraulic control circuit for controlling the gear position of the automatic transmission 14 and a lock-up clutch control hydraulic control for controlling engagement of the lock-up clutch 32. And a circuit. As is well known, the shift control hydraulic control circuit includes a first solenoid valve S1 and a second solenoid valve S2 that are driven on and off by solenoids No. 1 and No. 2, respectively. Valve S1
2 and FIG. 2 by a combination of operation of the second solenoid valve S2.
As shown in FIG. 7, the clutch and the brake are selectively operated to establish any one of the first to fourth gears.

The lock-up clutch control hydraulic control circuit is, for example, as shown in FIG. 4, 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. Lock-up relay valve 52 that is switched between a release side position in which lock-up clutch 32 is released and an engagement side position in which lock-up clutch 32 is engaged in accordance with use signal pressure P _sw.
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 device 184, and a linear solenoid valve S
A lock-up control valve 56 that controls the slip difference 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. Have.

In FIG. 4, a pump 60 for sucking and pumping the hydraulic oil recirculated to a tank (not shown) via a strainer 58 is driven to rotate by the engine 10. The operating hydraulic pressure pumped from the pump 60 is supplied to the first pressure regulating valve 62 of an overflow type by the first pressure regulating valve 62.
It is adapted to be pressurized line pressure Pl ₁ two-tone. This first
The pressure regulating valve 62 generates a first line pressure Pl ₁ that increases in accordance with the throttle pressure output from a throttle valve opening detection valve (not shown), and outputs the generated first line pressure Pl ₁ via a first line oil passage 64. The second pressure regulating valve 66 is an overflow type pressure regulating valve. The second pressure regulating valve 66 regulates the hydraulic oil discharged from the first pressure regulating valve 62 on the basis of the throttle pressure, so that the second pressure regulating valve 66 corresponds to the output torque of the engine 10. A line pressure Pl ₂ is generated. The third pressure regulating valve 68 is a pressure reducing valve that uses the first line pressure Pl ₁ as a source pressure, and generates a constant third line pressure Pl ₃ .

The lock-up relay valve 52 includes a release port 80 communicating with the release oil chamber 33 and an engagement oil chamber 35.
An input port 84 to which the second line pressure Pl ₂ is supplied, a first discharge port 86 through which hydraulic oil in the engagement oil chamber 35 is discharged when the lock-up clutch 32 is released, Second discharge port 8 through which hydraulic oil in release-side oil chamber 33 is discharged when lock-up clutch 32 is engaged.
8, a supply port 90 through which part of the hydraulic oil discharged from the second pressure regulating valve 66 is supplied for cooling during the engagement period of the lock-up clutch 32, and a spool valve element 92 for switching the connection state of those ports A spring 94 for urging the spool valve element 92 toward the off-side position; a plunger 96 disposed so as to be able to contact the end of the spool valve element 92 on the spring 94 side; the end face of the 96 the oil chamber 98 provided between them to exert a R range pressure P _R, the plunger 9
An oil chamber 100 for receiving the first line pressure Pl ₁ acting on the end face of the spool 6, and a third solenoid valve S 3
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.

The third solenoid valve S3 has a drain pressure in the oil chamber 102 of the lock-up relay valve 52 in a non-excited state (off state), but has a brake B _{2 in} an excited state (on state).
Exerting a switching signal pressure P _sw to source pressure to the oil chamber 102 of the pressure P _B2 to actuate the. For this reason, when the third solenoid valve S3 is in the off state, the third solenoid valve S3 is
Switching signal pressure from P _sw can not be allowed to act, since the spool 92 is brought into position off-side position according to a first line pressure Pl ₁ and acting on the biasing force and the oil chamber 100 of the spring 94, Input port 84 and release port 8
0, since the engagement side port 82 and the first discharge port 86 are communicated with each other, the oil pressure P _off in the release side oil chamber 33 is higher than the oil pressure P _on in the engagement side oil chamber 35, and the lock-up clutch 32 is released, and at the same time, the engagement side oil chamber 3
The hydraulic oil in 5 is discharged to the drain via 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 _Psw from the third solenoid valve S3 is applied to the oil chamber 102, and the spool valve 92 exerts the urging force of the spring 94. And the first line pressure P acting on the oil chamber 100
Since being is positioned on the ON side position against the and l _1, an input port 84 and the engagement-side port 82, the release side port 80 and the second exhaust port 88, the supply port 90 and communicating the first discharge port 86, respectively since provoking, at the same time the hydraulic pressure P lockup clutch 32 is also higher than _off in the hydraulic P _on the release side oil chamber 33 in the engaging-side oil chamber 35 is engaged, in the release side oil chamber 33 The hydraulic oil is supplied to the second discharge port 8
8 and discharged through the lock-up control valve 56 to the drain.

[0023] The linear solenoid valve SLU is the third line pressure Pl ₃ fixed to be generated in the third pressure regulating valve 68 to a pressure reducing valve to the source pressure, the shift electronic control unit as shown in FIG. 5 184 And generates a slip control signal pressure P _SLU that increases in accordance with the drive current I _SLU (ie, the drive duty ratio DSLU), and causes the slip control signal pressure P _SLU to act on the lock-up 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 to output the slip control signal pressure P _SLU , a spool valve element 114 for opening and closing them, and a spool valve element 114. 115 for urging the spool valve 114 in the valve closing direction, a spring 116 for urging the spool valve element 114 in the valve opening direction with a smaller thrust than the spring 115, and applying the spool valve element 114 in the valve opening direction in accordance with the drive current _ISLU . And an oil chamber 120 for receiving a feedback pressure (slip control signal pressure P _SLU ) for generating a thrust in the valve closing direction on the spool valve element 114. 114 is an electromagnetic solenoid 1
The urging force in the valve opening direction by the spring 18 and the spring 116 and the urging force in the valve closing direction by the spring 115 and the feedback pressure are operated so as to be balanced.

The lock-up control valve 56 has a line pressure port 130 to which the second line pressure Pl ₂ is supplied,
Release-side oil chamber 33 discharged from the second discharge port 88
A receiving port 132 for receiving the hydraulic oil therein, a drain port 134 for discharging the hydraulic oil received in the receiving port 132, and a communication between the receiving port 132 and the drain port 134 to allow the release side oil chamber 33 , The pressure in the disengagement-side oil chamber 33 is lowered to reduce the pressure difference ΔP (= P) between the engagement-side oil chamber 35 and the disengagement-side oil chamber 33.
P _on -P _off ) (the position on the left side in FIG. 4), the receiving port 132 and the line pressure port 130
With the second line pressure P in the release side oil chamber 33.
The spool valve element 136 movably provided between the position (the right position in FIG. 4) on the side that reduces ΔP by supplying l ₂ and increasing the pressure in the release-side oil chamber 33.
And a plunger 138 arranged to be able to contact the spool valve element 136 to urge the spool valve element 136 toward the first position, and to apply the slip control signal pressure P _SLU to the plunger 138. To generate a thrust in the direction toward the first position.
Signal pressure oil chamber 140 for receiving _SLU and plunger 13
An oil chamber 142 that receives the oil pressure P _off to cause the plunger 138 to generate a thrust toward the first position by causing the oil pressure P _off in the release-side oil chamber 33 to act on the plunger 138; An oil chamber 144 that receives the oil pressure P _on to apply a hydraulic pressure P _on in the engagement side oil chamber 35 to the valve element 136 to generate a thrust in the direction toward the second position on the spool valve element 136; A spring 146 housed within the chamber 144 and biasing the spool valve element 136 toward its second position.

Here, the plunger 138 is formed with a first land 148 and a second land 150 having cross-sectional areas A ₁ and A ₂ increasing in order from the oil chamber 142 side. the third land 152 and the fourth land 154 is formed is a cross-sectional area a ₃ from the signal pressure oil chamber 140 side. Accordingly, the plunger 138 abuts on the spool valve element 136 and operates integrally with each other, and a pressure difference ΔP (= P _on −P) having a magnitude corresponding to the slip control signal pressure P _{SLU is applied} to both sides of the piston 30.
_off ) is formed. That is, assuming that A ₁ = A ₃ , the pressure difference ΔP changes according to the slope [(A ₂ −A ₁ ) / A ₁ ] with respect to the slip control signal pressure P _{SLU according} to Equation 1. In Equation 1, F _s is the spring 1
Forty-six urging forces.

[0026]

(Equation 1)

FIG. 6 shows a change characteristic of the pressure difference ΔP obtained by the operation of the lock-up control valve 56 configured as described above, with respect to the slip control signal pressure P _SLU . Therefore, the lock-up relay valve 52
Is in the on state, the slip control signal pressure P _SLU
Becomes larger, the engagement-side oil chamber 35 and the release-side oil chamber 33 are increased.
Is increased, the slip rotation speed NSLP of the lock-up clutch 32 is reduced.
Conversely, the pressure difference ΔP between the engagement-side oil chamber 35 and the release-side oil chamber 33 decreases as the slip control signal pressure P _SLU decreases, so that the slip rotation speed NSLP of the lock-up clutch 32 increases. You.

[0028] Returning to FIG. 3, the intake air in the vehicle, the engine speed sensor 160 for detecting the rotational speed N _P of the rotational speed N _E i.e. the pump impeller 18 of the engine 10, is sucked 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
The intake air temperature sensor 164 for detecting the temperature T _AIR of the intake air sucked to zero, the throttle sensor 1 with an idle switch for detecting the fully closed state and the opening θ ₁ of the throttle valve 166 opened and closed by operating the accelerator pedal 165.
67, a vehicle speed sensor 168 for detecting the rotation speed of the output shaft of the automatic transmission 14, that is, the vehicle speed V, a cooling water temperature sensor 170 for detecting the cooling water temperature T _WA of the engine 10, and a brake sensor 172 for detecting that the brake pedal is operated. ,
Operation position of the shift lever 174 P _s That L,
2, an operation position sensor 176 for detecting any of the D, N, R, and P ranges, and a rotation speed N of the turbine wheel 22
_T, ie, a turbine rotation speed sensor 178 for detecting the rotation speed of the input shaft 20 of the automatic transmission 14, and the hydraulic control circuit 4
4 is provided with an oil temperature sensor 180 for detecting the temperature T _OIL of the hydraulic oil. The signals output from the sensors are directly or indirectly supplied to the electronic control unit 182 for the engine and the electronic control unit 184 for shifting. The electronic control unit 182 for the engine and the electronic control unit 184 for shifting are interconnected via a communication interface so that input signals and the like are supplied to each other as needed.

The electronic control unit 184 for shifting is a CPU, an R
A so-called microcomputer including an OM, a RAM, an interface, and the like. The CPU processes an input signal according to a program stored in a ROM in advance while using a temporary storage function of the RAM, and controls a shift of the automatic transmission 14 and The engagement control of the lock-up clutch 32 is executed according to a main routine (not shown), and the first solenoid valve S
1, the second solenoid valve S2, the third solenoid valve S3, and the linear solenoid valve SLU are respectively controlled.

In the above-described shift control, the data is stored in the ROM in advance.
Corresponding to the actual gear stage from multiple types of shift diagrams
The shift diagram is selected, and the running state of the vehicle is
Condition, for example, throttle valve opening θ₁And vehicle speed V
The gear position is determined by the
The first solenoid valve S1 and the second solenoid valve S2 are driven
As a result, the clutch C of the automatic transmission 14₀ , C₁ , C_Two ,
And brake B₀ , B ₁ , B_Two , B_Three Operation is controlled
And one of the four forward gears is established
You.

The engagement control of the lock-up clutch 32 is executed, for example, during traveling at the third speed and the fourth speed, and the engagement control is previously stored in the ROM. Based on the relationship shown in FIG. 7, based on the traveling state of the vehicle, for example, the output shaft rotation speed (vehicle speed) _Nout and the throttle valve opening TAP, any one of the release region, the slip control region, and the engagement region of the lock-up clutch 32 is performed. It is determined whether there is. This slip control area is
The lock-up clutch 32 is maintained in a slip state so as to be connected while absorbing torque fluctuations of the engine 10 for the purpose of improving fuel efficiency as much as possible without impairing drivability. FIG. 7 is used during acceleration running of the vehicle. Further, even during deceleration coasting of the vehicle, slip control of the lock-up clutch 32 is executed for the purpose of expanding the control range of the fuel cut control. That is, in the coasting state where the throttle valve opening TAP is zero, the slip control is executed until the fuel cutoff operation by the fuel cut device is terminated.

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

[0033]

(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, KGD is a learning control value formed corresponding to characteristics of each machine, and DFB is a learning control value. For example, as shown in Expression 3, the feedback control value is obtained by adding a proportional value, a differential value, and an integral value of the deviation ΔE.

[0035]

(Equation 3)

An electronic control unit 182 for the engine
This is also a microcomputer similar to the electronic control unit 184 for shifting, and its CPU executes various engine controls by processing input signals in accordance with a program stored in a ROM in advance. For example, in the fuel injection amount control, the fuel injection valve 186 is controlled in order to optimize the combustion state, in the ignition timing control, the igniter 188 is controlled in order to make the retard amount appropriate, and in the traction control, the driving wheels are controlled. Throttle actuator 190 for preventing slip and ensuring effective driving force and vehicle stability.
The second throttle valve 192 is controlled by, the fuel-cut control, in order to improve the fuel consumption, for a period exceed the fuel cut-off rotation speed N _CUT to engine rotational speed N _E is set in advance in the coasting fuel injection valve 186
Close.

FIG. 8 shows the electronic control unit 184 for shifting.
FIG. 3 is a functional block diagram illustrating a main part of a control function. Figure
At S8, when the vehicle enters, for example, a decelerating state,
The lip control means 196 controls the lock-up clutch 32
Actual slip rotation speed NSLP (= N_E-N_T)When,
Target slip rotation speed preset to several tens of r.p.m.
In order to make TNSLP coincide with TNSLP, the control formula of Expression 2 is used.
The calculated control value DSLU is output. Lock-up co
The control valve switching control means 200 includes a vehicle speed determination means 19.
8, the vehicle speed V is set to a predetermined reference value V_SL1Also
Is V_SL2If it is determined that
From the chamber 33 through the lock-up relay valve 52
To the side where the hydraulic oil pressure is high, ie, the right side position in FIG.
Switching the lock-up control valve 56 preferentially
Control signal pressure P _SLUTo minimize
The control value DSLU is set to the maximum (= 100%).

In the vehicle, for example, the shift operation lever 17
4 is operated to the second range and the switch for starting the second gear (not shown) is operated, or the shift operation lever 174 is operated to the D range and the switch for starting the second gear (not shown) is operated. In this case, the lowest gear in the shift range of the automatic transmission 14 is set to the second gear, which corresponds to the shift operation lever 174 and the switch for starting the second gear. The shift range switching means 202 changes the lowest gear in the shift range of the automatic transmission 14 according to the driver's operation.
The judgment criterion value changing means 204 is provided with the above-mentioned shift range switching means 2.
When the lowest gear stage changed in step 02 is achieved, the reference value of the vehicle speed is changed according to the lowest gear stage. For example, when the lowest gear is the first gear, the judgment reference value V _SL2 is changed. When the lowest gear is the second gear, the judgment reference value V _SL1 is changed to a value larger than the judgment reference value V _SL2. I do.

FIG. 9 is a flow chart for explaining a main part of the control operation of the electronic control unit 184 for shifting. This flowchart shows an operation that enables starting in the second gear when the shift operation lever 174 is operated in the second range and the second speed start switch is operated. In the figure, in step SS1 (hereinafter, the steps are omitted), it is determined whether or not the shift operation lever 174 has been operated to the neutral (N) range. If the determination of SS1 is affirmed, SS2
, The drive duty ratio DSLU is set to 0%, so that the linear solenoid valve SLU is de-energized.

If the determination in SS1 is denied, in subsequent SS3 and SS9, the shift operation lever 17
It is determined whether or not No. 4 has been operated to the second (2) range and whether or not the second speed gear start switch has been operated. That is, in SS3 and SS9, it is determined how the lowest gear in the shiftable range of the automatic transmission 14 selected according to the driver's operation is set. Therefore, SS3 and SS9
Is an automatic transmission 14 set according to the operation by the driver.
SS7 and S according to the lowest gear of the shift range
This corresponds to the criterion value changing means 204 for changing the criterion value of the vehicle speed V in S10. Note that SS3 and SS
Reference numeral 9 can be replaced with a means for determining which shift speed is the lowest gear position that can be set in the shift range of the automatic transmission 14.

In the normal D-range running, since the determination in SS3 is denied, it is determined in SS4 whether the automatic transmission 14 has been set to the first gear or the reverse gear. In the forward running at the second speed or higher, the determination in SS4 is negative, so in SS5, for example, it is determined whether or not the vehicle is in the full engagement region or the slip control region in FIG. If the determination in SS5 is negative, the region is in the release range, so in SS2, the third solenoid valve S3 is turned off, the lock-up clutch 32 is released, and the drive duty ratio DSLU is set to 0%. . However, if the determination at SS5 is affirmative, at SS6, the drive duty ratio DSLU according to the area is output. For example, the drive duty ratio DSLU is set to 100% in the complete engagement region, and the drive duty ratio DS determined in accordance with the above equation 2 in the slip control region.
LU is output. In this sense, SS6 corresponds to slip control means 196.

When the vehicle speed is reduced in the D-range running of the vehicle, or when the vehicle is temporarily stopped and the shift operation is performed to switch the automatic transmission 14 to the first gear, or the vehicle is temporarily stopped and the shift operation is performed. If the vehicle is switched to the reverse gear, the determination at SS4 is affirmative, and it is determined at SS7 whether the vehicle speed V is equal to or less than a predetermined reference value _VSL2 . This determination reference value V _SL2 is set to a vehicle speed value corresponding to the idling rotation speed or a substantially lowest vehicle speed value that does not cause the engine 10 to stall when traveling at the first gear.

[0043] If the above SS7 determination is negative, since in high running state than the vehicle speed V is still determination reference value V _SL2, the driving duty ratio DSLU in SS8 0%
Is set to At this time, the engagement state of the lock-up clutch 32 is controlled according to the lock-up relay valve 52. However, in an abnormal state such as the on-side stick of the lock-up relay valve 52, the drive duty ratio DSLU
Is set to 0%, the lock-up clutch 32 is engaged. However, determination of the SS7 is if it is affirmative, the vehicle speed V is in the low traveling state than the determination reference value V _SL2, the driving duty ratio DSLU in SS12 is set to 100%. Therefore, the lock-up relay valve 52 and the lock-up clutch 32 are normally switched to the off state at such a low vehicle speed. However, in an abnormal state such as the on-side stick of the lock-up relay valve 52, Drive duty ratio D
The control signal pressure P _SLU is set by setting the SLU to 100%.
Is the minimum value, the line pressure port 130 and the receiving port 132 of the lock-up control valve 56, the second discharge port 88 of the lock-up relay valve 52, and the release port 80
When the second line pressure Pl ₂ is supplied to the release-side oil chamber 33 via the pressure control valve, the pressure difference ΔP on both sides of the piston 30 is reduced to zero as shown in FIG.
2 is substantially released.

On the other hand, when the second range is selected by the shift operation lever 174, the determination in SS3 is affirmative. In the next SS9, the second gear start switch (not shown) switches the second gear into the second gear. It is determined whether the start is set. That is, it is determined whether or not the lowest gear in the shift range of the automatic transmission 14 is set to the second gear in association with the selection of the second range.

If the determination at SS9 is negative,
The lowest gear in the shift range of the automatic transmission 14 is the first gear.
It is a high gear stage and the start is in the first gear stage.
Step SS4 and subsequent steps are executed. However, SS9
Is affirmative, it means that the second gear start is set, and it is determined in SS10 whether or not the vehicle speed V is equal to or less than a predetermined reference value _VSL1 . This criterion value V _SL1 is equal to the criterion value V _SL2.
A vehicle speed value corresponding to the idling rotational speed when traveling in the second gear, or the engine 1
The vehicle speed is set to a substantially lowest vehicle speed at which no stall occurs.

If the determination in SS10 is negative,
Since the vehicle speed V is still in a running state higher than the reference value V _SL1 , the drive duty ratio DSLU is set to 0% in SS11. At this time, the lock-up relay valve 5
In the abnormal state such as the on-side stick of No. 2, the lock-up clutch 32 is engaged by setting the drive duty ratio DSLU to 0%. However, when the determination in SS10 is affirmed, the vehicle is running in the vehicle speed V equal to or less than the determination reference value V _SL1 ,
, The drive duty ratio DSLU is set to 100%. Therefore, the lock-up relay valve 52 and the lock-up clutch 32 are normally switched to the off state at such a low vehicle speed. However, in an abnormal state such as the on-side stick of the lock-up relay valve 52, By setting the drive duty ratio DSLU to 100%, the control signal pressure P _SLU is set to the minimum value, and the line pressure port 130, the receiving port 132 of the lock-up control valve 56, the second discharge port 88 of the lock-up relay valve 52, When the second line pressure Pl ₂ is supplied to the release-side oil chamber 33 through the release-side port 80, the pressure difference ΔP on both sides of the piston 30 is reduced to zero as shown in FIG. 32 is substantially released.

As described above, according to the present embodiment, the vehicle speed V is set to a predetermined reference value V _SL1 or V _SL2 by SS7 or SS10 corresponding to the vehicle speed determination means 198.
If it is determined that the following has occurred, the lockup control valve switching control means 200
As a result, the lock-up relay valve 52
The lock-up control valve 56 is preferentially switched to the side that increases the pressure of the hydraulic oil discharged through the lock.
As described above, even if the lock-up clutch 32 is to be engaged in the region to be released due to the failure of the lock-up relay valve 52, the vehicle speed V is equal to or less than the predetermined reference value V _SL1 or V _SL2. Since the lock-up control valve 56 is preferentially switched to the side that raises the hydraulic oil discharged from the release-side oil chamber through the lock-up relay valve 52, the engagement-side oil chamber 35 of the lock-up clutch 32 Since the pressure difference ΔP from the release-side oil chamber 33 is reduced and the lock-up clutch 32 is substantially released, it is possible to prevent the drivability or running performance from being reduced due to the muffled noise of the engine vibration at low vehicle speed running. Is done.

According to this embodiment, the vehicle speed V is set in advance.
Determined criterion value V_SL1Or V _SL2When
Is the side on which the hydraulic oil discharged from the release side oil chamber 33 is raised.
The lock-up control valve 56 is switched uniformly
Therefore, the failure determination of the lock-up relay valve 52
There is an advantage that becomes unnecessary.

Further, according to the present embodiment, the shift range switching means 202 (shift operation lever 174) for changing the lowest gear in the shift range of the automatic transmission 14 when operated by the driver; When the lowest gear changed by the shift range switching means 202 is achieved,
A criterion value changing means 2 for changing a criterion value of the vehicle speed used in the vehicle speed determining means 198 according to the lowest gear position.
Since 04 and (SS3) is provided, there is an advantage that can be as low as possible the determination reference value V _{SL 1} or V _SL2 without causing engine stall.

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

For example, the vehicle speed judging means 1 of the above embodiment
98 instead of the engine speed N _EOr turbine blade
Rotation speed N of car 22_TIs less than or equal to a preset judgment reference value
Even if a judgment means for judging whether or not
Good. In short, the vehicle speed V is equal to the predetermined reference value V.
_SL1Or V_SL2It is virtually determined that
I just need to.

In SS12 of the above-described embodiment, the drive duty ratio DSLU is set to 100%. However, when the linear solenoid valve SLU has an output characteristic in which the control signal pressure P _SLU increases as the drive current increases. Is SS1
In 2, the drive duty ratio DSLU is set to 0%.

The above is merely an example of the present invention, and the present invention can be variously modified without departing from the gist thereof.

[Brief description of the drawings]

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

FIG. 2 is a diagram showing an automatic transmission including the torque converter with a lock-up clutch shown in FIG. 1;
5 is a table illustrating a relationship between a combination of operation of solenoid valves and a shift speed obtained by the combination.

FIG. 3 is a block diagram illustrating a configuration of a control device provided in the vehicle of FIG. 1;

FIG. 4 is a diagram illustrating a configuration of a main part of a hydraulic control circuit in FIG. 3;

FIG. 5 is a diagram showing output characteristics of the linear solenoid valve of FIG. 4;

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.

FIG. 7 is stored in the shift electronic control device of FIG.
FIG. 4 is a diagram illustrating a relationship between a traveling state of a vehicle and a control region of a lock-up clutch.

8 is a functional block diagram for explaining a main part of a control function of the shift electronic control device of FIG. 3;

FIG. 9 is a flowchart illustrating a main part of a control function of the shift electronic control device of FIG. 3;

[Explanation of symbols]

 18: Pump impeller 22: Turbine impeller 32: Lockup clutch 52: Lockup relay valve 56: Lockup control valve 196: Slip control means 198: Vehicle speed judgment means 200: Lockup control valve switching control means

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-5-99331 (JP, A) JP-A-5-106730 (JP, A) JP-A-56-176793 (JP, A) JP-A-59-1979 99159 (JP, A) JP-A-60-207661 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) F16H 61/14

Claims (3)

(57) [Claims] In a vehicle having a lock-up clutch between a pump impeller and a turbine impeller, hydraulic oil is supplied to one of a release-side oil chamber and an engagement-side oil chamber of the lock-up clutch and operated from the other. A lock-up relay valve for discharging oil and a side for engaging the lock-up clutch
The release through the switched lock-up relay valve
A lock control clutch for a vehicle, comprising a lock-up control valve for adjusting a slip amount of a lock-up clutch by adjusting a pressure of hydraulic oil discharged from a side oil chamber , wherein a vehicle speed is preset. Vehicle speed determining means for determining whether the vehicle speed has become equal to or less than the determined reference value , and the vehicle speed determining means has determined that the vehicle speed has become equal to or less than the reference value in an area where the lock-up clutch is to be released .
Until it is determined that
Pressure of the hydraulic oil discharged through the relay valve
The lock-up control valve is switched to the lower side, but when it is determined that the vehicle speed has become equal to or less than the determination reference value, the pressure of the hydraulic oil discharged from the release-side oil chamber through the lock-up relay valve is increased. And a lock-up control valve switching control means for preferentially switching the lock-up control valve to a side of the vehicle. 2. The lock-up control valve switching system.
The control means controls the vehicle when the lowest speed gear is attained.
When the vehicle speed falls below the reference value by the speed determination means,
Until the determination, the lock-up from the release-side oil chamber
Reduce the pressure of hydraulic oil discharged through the pre-lay valve
Switch the lock-up control valve to the
Is determined to be equal to or less than the determination reference value,
From the release side oil chamber through the lockup relay valve
Lock-up connector on the side that increases the pressure of discharged hydraulic oil
2. The control valve according to claim 1, wherein the control valve is switched.
Slip control device for vehicle lock-up clutch. 3. The vehicle according to claim 1, further comprising a stepped transmission.
The backup control valve switching control means includes a second speed gear.
In the state where the step is achieved, the vehicle speed
Until the speed is determined to be equal to or less than the determination reference value,
The release side oil chamber Through the lock-up relay valve
Lock-up connector on the side that lowers the pressure of discharged hydraulic oil
Control valve is switched, but the vehicle speed is lower than the reference value.
If it is determined to be below, from the release side oil chamber
Hydraulic oil discharged through the lock-up relay valve
Turn off the lock-up control valve on the side that increases the pressure
The vehicle lock according to claim 1 or 2, which is a replacement.
A slip control device for the clutch.