JP3120743B2 - 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 control device for a lock-up clutch for a vehicle, and more particularly to a control when an accelerator operation means is turned on during engagement control during deceleration.

[0002]

2. Description of the Related Art Vehicles provided with a fluid transmission device such as a torque converter or a fluid coupling between an engine and driving wheels are widely known as automatic vehicles that do not require a clutch operation. A hydraulic lock-up clutch is disposed in parallel with the above-mentioned fluid transmission device in one kind of such a vehicle, and when the vehicle is running at a predetermined deceleration, that is, at the time of engine braking while the accelerator operation amount is substantially zero, the engine is driven. In order to increase the rotational speed to enlarge the fuel cut region or to apply a relatively large deceleration G to the vehicle, a deceleration engagement control for engaging the lock-up clutch (including slip engagement) is performed. There is something that I did. The device described in Japanese Patent Application No. 7-213127 filed earlier by the applicant of the present application is an example of such a device that performs slip control as engagement control during deceleration and operates an accelerator during the slip control. Even when the means is turned ON, the slip control is continued on condition that the turbine rotational speed is equal to or higher than a predetermined value.

[0003]

However, when the slip control of the lock-up clutch is continued uniformly on condition that the turbine rotational speed is equal to or higher than a predetermined value, for example, a shift from deceleration running to rapid acceleration is made. In such a case, the slip state may be reversed to cause a shock. Conversely, when the slip control of the lock-up clutch is stopped uniformly when the turbine rotation speed is equal to or lower than the predetermined value, if the operation of the accelerator operation means is released again, the deceleration G cannot be obtained or the slip control is not performed. , It takes time until the deceleration G is obtained, and a sense of incongruity occurs.

The present invention has been made in view of the above circumstances, and has as its object to control the engagement of the lock-up clutch when the accelerator operating means is turned ON during the engagement control during deceleration. In order to more appropriately determine whether or not to continue.

[0005]

In order to achieve the above object, the present invention provides a deceleration engagement control means for engaging a lock-up clutch arranged in parallel with a fluid transmission during predetermined deceleration travel. A control device for a vehicle lock-up clutch having (a) accelerator operation detecting means for detecting whether an accelerator operating means operated in response to a required output has been turned on, and (b) an accelerator operation detecting means for the current vehicle. (C) during the engagement control by the deceleration engagement control means, the accelerator operation detection means turns on the accelerator operation means by the accelerator operation detection means; And when the downhill road detecting means detects that the vehicle is traveling on a downhill road, there is provided engagement control continuation means for continuing the engagement control. And

According to a second aspect of the present invention, in the first aspect, the accelerator operation detecting means detects that the accelerator operation means has been turned on during the engagement control by the deceleration engagement control means, When the downhill road detecting means detects that the vehicle is traveling on a place other than the downhill road, an engagement control stopping means for stopping the engagement control is provided.

[0007]

According to the control apparatus for a vehicle lock-up clutch, even if the accelerator operation means is turned ON during the engagement control by the engagement control means during deceleration,
When the vehicle is traveling on a downhill road, the engagement control is continued. Therefore, when the accelerator operation amount is small, the deceleration G by the engine brake or the like is continuously obtained, and the large deceleration G with the accelerator OFF is obtained. , And drivability is improved. Also, while traveling downhill,
It is extremely rare to suddenly accelerate the vehicle by greatly operating the accelerator operation means. Therefore, even if the engagement control of the lock-up clutch is continued, there is little possibility that a shock will be generated due to the sudden acceleration.

In the second aspect, when the vehicle is traveling on a road other than a downhill road, that is, on a flat road or an uphill road, the engagement control by the deceleration engagement control unit is stopped by turning on the accelerator operation unit. Also, when the vehicle shifts from deceleration running to rapid acceleration, a shock caused by maintaining the engagement of the lock-up clutch is prevented.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The above-mentioned fluid transmission device is generally disposed between a power source and driving wheels, and an engine is preferably used as the power source. As the fluid transmission, a torque converter is preferably used, but a fluid coupling or the like may be used. The lock-up clutch is
For example, one in which the friction material is engaged and released by moving the piston by hydraulic pressure is preferably used.

At the time of deceleration running in which the deceleration engagement control is performed,
For example, when the accelerator operation amount is substantially zero and the engine brake is applied and the vehicle is running at a speed equal to or higher than a predetermined vehicle speed, the control start condition, the control stop condition, and the like are appropriately set. In the deceleration engagement control, the lock-up clutch is fully engaged (slip amount =
0), but may be a slip engagement with a predetermined slip amount.

The downhill road detecting means detects a downhill road, for example, when the descent angle is equal to or more than a predetermined angle. For example, a reference acceleration on a flat road is calculated by using a throttle valve opening and a vehicle speed as parameters. It can be determined from an equation, a map, or the like, and whether or not the vehicle is on a downhill can be determined based on whether or not the actual vehicle acceleration is greater than the reference acceleration. It is also possible to directly detect the road surface gradient using an inclination angle sensor or the like.

In the second invention, the engagement control by the engagement control means during deceleration is stopped by the ON operation of the accelerator operation means when the vehicle is traveling on a place other than a downhill road. Can be implemented in various modes, for example, by determining whether to stop the engagement control in consideration of other operation states such as the operation amount of the accelerator operation means.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a skeleton diagram of a vehicle drive device 8 including a control device for a vehicle lock-up clutch according to one embodiment of the present invention. The output of an engine 10 as a power source is automatically output via a torque converter 12. The data is input to the transmission 14 and transmitted to drive wheels via a differential gear device and an axle (not shown). The torque converter 12 corresponds to a fluid transmission, and includes a pump impeller 18 connected to a crankshaft 16 of the engine 10 and a turbine impeller 22 connected to an input shaft 20 of the automatic transmission 14.
In order to directly connect the pump impeller 18 and the turbine impeller 22, the pump impeller 18 and the turbine impeller 22 are fitted to the hub shaft of the turbine impeller 22 so as to be movable in the axial direction and to be relatively non-rotatable. A lock-up clutch 24 connected to the input shaft 20 via a piston 23, and a stator 2 which is prevented from rotating in one direction by a one-way clutch 26.
8 is provided. The lock-up clutch 24 is adapted to be engaged or disengaged by hydraulic friction force.

The automatic transmission 14 includes a first transmission 30 for switching between high and low gears, and a second transmission 32 for switching between one reverse gear and four forward gears. The first transmission 30 includes a sun gear S0, a ring gear R
0 and an HL planetary gear unit 34 comprising a planetary gear P0 rotatably supported by the carrier K0 and meshed with the sun gear S0 and the ring gear R0, and a clutch C provided between the sun gear S0 and the carrier K0.
0 and a one-way clutch F0, and a brake B0 provided between the sun gear S0 and the housing 41.

The second transmission 32 has a first planetary gear unit 36 comprising a sun gear S1, a ring gear R1, and a planetary gear P1 rotatably supported by the carrier K1 and meshed with the sun gear S1 and the ring gear R1.
, Sun gear S2, ring gear R2, and carrier K
2, a second planetary gear set 38 comprising a planet gear P2 rotatably supported by the sun gear S2 and the ring gear R2, and a sun gear rotatably supported by the sun gear S3, the ring gear R3, and the carrier K3. And S3 and a third planetary gear set 40 including a planetary gear P3 meshed with the ring gear R3.

The sun gear S1 and the sun gear S2 are integrally connected to each other, the ring gear R1, the carrier K2 and the carrier K3 are integrally connected, and the carrier K3 is connected to the output shaft 42. Further, a ring gear R2 is integrally connected to the sun gear S3. A clutch C1 is provided between the ring gear R2 and the sun gear S3 and the intermediate shaft 44, and the sun gear S1 and the sun gear S3 are provided.
A clutch C2 is provided between the clutch shaft 2 and the intermediate shaft 44. A band-type brake B1 for stopping rotation of the sun gear S1 and the sun gear S2 is provided on the housing 41.
It is provided in. A one-way clutch F1 is provided between the housing 41 and the sun gear S1 and the sun gear S2.
And a brake B2 are provided in series. The one-way clutch F1 is configured to be engaged when the sun gear S1 and the sun gear S2 try to reversely rotate in the direction opposite to the input shaft 20.

A brake B3 is provided between the carrier K1 and the housing 41, and a brake B4 and a one-way clutch F2 are provided between the ring gear R3 and the housing 41 in parallel. This one-way clutch F
2 is configured to be engaged when the ring gear R3 attempts to rotate in the reverse direction.

The automatic transmission 14 constructed as described above
For example, according to an operation table shown in FIG. 2, a first reverse speed and a fifth forward speed are established. In FIG. 2, ○ indicates an engaged state, X indicates a disengaged state, and ◎ indicates that the lock-up clutch 24 is operated when engaged or slipped. As is clear from FIG. 2, in the 3 → 4 shift from the third shift stage (3rd) to the fourth shift stage (4th), the clutch C2 is engaged and the fourth shift stage to the fifth shift stage ( 4th to 5th)
In the fifth shift, the clutch C0 is released and the brake B0 is engaged. In the fourth gear, the input shaft 20 and the output shaft 42 of the automatic transmission 14 have the same rotational speed.

As shown in FIG. 3, a first throttle valve 52 operated by an accelerator pedal 50 and a throttle actuator 54 are provided in an intake pipe of the engine 10 of the vehicle.
And a second throttle valve 56 operated by the controller. The engine rotational speed sensor 58, the intake air quantity sensor 60 for detecting an intake air quantity Q of the engine 10, the intake air temperature sensor 62 for detecting the temperature THa of intake air for detecting the rotational speed N _E of the engine 10, the first 1 A throttle sensor 64 with an idle switch for detecting the opening TA of the throttle valve 52, a vehicle speed sensor 66 for detecting a vehicle speed V from the rotational speed N _O of the output shaft 42, etc., and the engine 10
A coolant temperature sensor 68 for detecting the coolant temperature THw, a brake switch 70 for detecting the operation of the brake, and an operation position sensor 7 for detecting the operation position Psh of the shift lever 72.
4 and the like, and from these sensors, the engine rotation speed N _E , the intake air amount Q, the intake air temperature THa,
The opening degree TA of the first throttle valve, the vehicle speed V, the engine coolant temperature THw, the operating state BK of the brake, the shift lever 72
A signal representing the operating position Psh of the electronic control unit 7 for the engine
6 and the electronic control unit 78 for shifting. A turbine rotation speed sensor 75 that detects the input shaft rotation speed N _IN substantially by detecting the rotation speed _NT of the turbine wheel 22 or the rotation speed (clutch rotation speed) N _C0 of the clutch drum of the clutch C0; and from an oil temperature sensor 77 for detecting the working oil temperature T _oIL, signals respectively representative of the turbine speed N _T and the hydraulic fluid temperature T _oIL is supplied to the shift electronic control unit 78.

The engine electronic control unit 76 includes a CPU,
This is a so-called microcomputer having a RAM, a ROM, and an input / output interface. The CPU processes input signals in accordance with a program stored in the ROM in advance while using the temporary storage function of the RAM, and executes various engine controls. For example, the fuel injection valve 80 is controlled for controlling the fuel injection amount, the igniter 82 is controlled for controlling the ignition timing, and the throttle valves 52 and 56 are provided in parallel with the throttle valves 52 and 56 for controlling the idling speed of the engine 10. An ISC (idle rotation speed control) valve 83 is controlled, and a second throttle valve 56 is controlled by a throttle actuator 54 for traction control and the like. Further, in the fuel cut control, for example, during deceleration of the vehicle, such as the first throttle valve 52 is fully closed, the fuel injection in the predetermined fuel cut-off rotation speed N engine speed N _E is higher period than _cut Valve 80 is closed.

The shift electronic control unit 78 is also a microcomputer similar to the above, and the CPU processes input signals in accordance with a program stored in the ROM 79 in advance while utilizing the temporary storage function of the RAM, and the hydraulic control circuit 84 Drive each solenoid valve or linear solenoid valve. For example, the electronic control unit 78 for the speed change
The linear solenoid valve SLT is used to generate an output pressure P _SLT having a magnitude corresponding to the opening degree TA, the linear solenoid valve SLN is used to control the accumulating back pressure, and the lock-up clutch 24 is engaged or slipped. Each of the linear solenoid valves SLU is driven to control the amount.
Further, the shift electronic control device 78 determines the gear position of the automatic transmission 14 and the engagement state of the lock-up clutch 24 based on the actual throttle valve opening TA and the vehicle speed V from a shift diagram stored in advance. When the solenoid valves S1, S2 and S3 are driven so as to obtain the determined shift speed and engagement state, and the engine brake is generated, the solenoid valve S4
Is not driven.

The shift electronic control unit 78 further executes the engagement control and the slip control of the lock-up clutch 24, and locks up at the first speed (1st) and the second speed (2nd) of the automatic transmission 14. The clutch 24 is disengaged from the third gear (3rd) to the fifth gear (5t).
In h), for example, the relationship shown in FIG. 4 corresponding to the shift speed of the automatic transmission 14 is selected from the plurality of types of relationships stored in the ROM 79 in advance, and the throttle valve opening T
A, the vehicle speed (output shaft rotation speed corresponding to N _O) released on the basis of V, slip control, determine one of the regions of engagement, if the release or engagement region, the lock-up clutch 24
Is released or engaged (completely engaged). In the slip control region, the shift electronic control unit 78 executes the slip control of the lock-up clutch 24.

In the above-described slip control, in order to improve the fuel efficiency as much as possible without impairing the drivability in the driving state of the vehicle, the rotational fluctuation of the engine 10 is connected while absorbing the fluctuation of the rotation of the engine 10 to reduce the rotational loss of the torque converter 12. Is suppressed as much as possible, the lock-up clutch 24 is maintained in the slip state. Further, even in a non-drive traveling state or during deceleration coasting of the vehicle, or to expand the control range of the fuel cut control of the engine rotational speed N _E is increased than the fuel-cut rotational speed N _cut, or by the action of large reduction G in the vehicle For the purpose of, for example, performing the deceleration slip control as the deceleration engagement control of the lock-up clutch 24, is performed. This deceleration slip control is executed on condition that the throttle valve opening TA is substantially zero, that is, the idle switch of the throttle sensor 64 is ON, and the vehicle speed V is equal to or higher than a predetermined value.

In the above-described slip control, the actual slip amount N _{slip is calculated} according to a slip control routine (not shown).
(= N _E -N _T ) is calculated, and the linear solenoid valve SLU is set in accordance with, for example, the following equation (1) so that the preset target slip amount N _slip ^T and the actual slip amount N _slip match.
, Ie, the drive duty ratio DSLU (%) is calculated, and the control pressure P _SLU output from the linear solenoid valve _SLU is adjusted. DSLU = DFWD + DFB (1)

In the above equation (1), DFWD is, for example,
Feedforward as a function of engine 10 output torque
DFB is, for example, the target slip
Quantity N _slip ^TAnd actual slip amount N_slipDeviation ΔN between_slip
(= N_slip-N_slip ^T)
Control output value. These DFWD and DFB are
It is a quantity converted into a plant ratio and its unit is%.
The feedback control output value DFB is a well-known
It is calculated from the PID control formula. (1)
The burden of the feedback control output value DFB
A learning correction term is provided as necessary to reduce
It is.

FIG. 5 shows a main part of the hydraulic control circuit 84. In the figure, the control linear solenoid valve SLU which functions as the pressure generating valve, a pressure reducing valve to a source pressure modulator pressure P _M, the driving duty ratio to be outputted from the shift electronic control unit 78 as shown in FIG. 6 The control pressure P _SLU that increases with the DSLU is output and supplied to the lock-up relay valve 98 and the lock-up control valve 100.

The lock-up relay valve 98 can contact each other, and the first spool valve 104 and the second spool valve 1 having a spring 102 interposed therebetween.
06 and the first spool valve element 104 and the second spool valve element 1 provided on the shaft end side of the first spool valve element 104.
Control pressure P in order to urge No. 06 to the engagement (ON) side position.
Oil chamber 108 for receiving _SLU and first spool valve 10
And an oil chamber 110 for receiving the second line pressure P _L2 for urging the fourth and second spool valve elements 106 to the release side position. The first spool valve 104 is released (OF).
F), when the second line pressure P _L2 supplied to the input port 112 is supplied from the release port 114 to the release oil chamber 116 of the torque converter 12, The hydraulic oil in the oil chamber 118 is discharged from the engagement side port 120 to the cooler bypass valve 124 or the oil cooler 126 via the discharge port 122. On the contrary, when the first spool valve element 104 is located at the engagement side position, the second line pressure P _L2 supplied to the input port 112 is supplied from the engagement side port 120 to the engagement side oil chamber 118 of the torque converter 12. As supplied,
The hydraulic oil in the release-side oil chamber 116 of the torque converter 12 is discharged from the release-side port 114 through the discharge port 128, the control port 130 of the lock-up control valve 100, and the discharge port 132.

Therefore, when the control pressure P _SLU is equal to or lower than the predetermined value, the first spool valve element 104 is released (OFF) on the right side of the center line in FIG. 5 according to the thrust based on the second line pressure P _L2 . When the control pressure P _SLU exceeds a predetermined value, the first spool valve element 104 moves from the center line in FIG. 5 according to the thrust based on the second line pressure P _L2 . The lock-up clutch 2 located at the engagement side (ON) position shown on the left side
4 is engaged or slipped. The engagement or slip state of the lock-up clutch 24 at this time is controlled by a lock-up control valve 100 that operates according to the magnitude of the control pressure P _SLU .

The lock-up control valve 100 is for controlling the slip amount of the lock-up clutch 24 in accordance with the control pressure P _SLU when the lock-up relay valve 98 is at the engagement side position.
And a plunger 136 that abuts on the spool valve element 134 to apply a thrust toward the discharge side position shown on the right side of the center line in FIG. 5, and the supply side position shown on the left side of the spool valve element 134 on the center line in FIG. 138 for applying a thrust toward the oil supply, and an oil for receiving the oil pressure P _on in the engagement side oil chamber 118 of the torque converter 12 to accommodate the spring 138 and to urge the spool valve element 134 toward the supply side position. An oil chamber 142 provided on the shaft end side of the plunger 136 and receiving the oil pressure P _off in the release oil chamber 116 of the torque converter 12 to bias the spool valve element 134 toward the discharge side position; , Plunger 1
An oil chamber 144 is provided at an intermediate portion of 36 and receives the control pressure P _SLU .

Therefore, when the spool valve element 134 is positioned at the discharge side, the connection between the control port 130 and the discharge port 132 is communicated, so that the engagement torque of the lock-up clutch 24 is increased. Conversely, when the control port 130 is located at the supply side position, the supply port 146 to which the first line pressure P _L1 is supplied communicates with the control port 130, so that the first line pressure P _L1 is connected to the release side of the torque converter 12. The engagement torque of the lock-up clutch 24 supplied to the oil chamber 116 is reduced. That is, in the lock-up control valve 100, the differential pressure between the oil pressure P _on in the engagement-side oil chamber 118 of the torque converter 12 and the oil pressure P _off in the release-side oil chamber 116, that is, the engagement torque of the lock-up clutch 24 Is controlled in accordance with the control pressure P _SLU . The engagement torque of the lock-up clutch 24 corresponds to the engagement force.

Therefore, as the control pressure P _SLU increases beyond the predetermined value, the engagement torque of the lock-up clutch 24 is increased to reach full engagement. When the lock-up clutch 24 is released, the linear solenoid valve SLU is driven by the electronic shift control device 78 so that the control pressure P _SLU becomes smaller than the predetermined value. When the lock-up clutch 24 is engaged, the linear solenoid valve SLU is driven by the shift electronic control device 78 so that the control pressure P _SLU becomes the maximum value, and when the lock-up clutch 24 is slipped, The linear solenoid valve SLU is driven by the electronic shift control device 78 so that the control pressure P _SLU is between the predetermined value and the maximum value. That is, in the lock-up control valve 100, as shown in FIG. 7, since the oil pressure P _off in the release-side oil chamber 116 of the torque converter 12 is changed according to the control pressure P _SLU , the engagement pressures, that is, the oil pressures P _on and P pressure difference with _off (P _on −
P _off ), the engagement torque of the lock-up clutch 24 is also changed according to the control pressure _SLU, and the slip amount N
_{sl ip} is controlled.

The solenoid relay valve 170 is connected to the output port 1 connected to the oil chamber 108 of the lock-up relay valve 98.
72, a drain port 174, and a linear solenoid valve SL
The input port 176 to which the control pressure P _{SLU of} U is supplied, the lock-up release position where the output port 172 communicates with the drain port 174, and the output port 172 are connected to the input port 17
6, and a spring 18 for urging the spool valve 178 toward the lock-up permission position.
0 and an orifice for engaging pressure P _{B2 of} brake B2 generated in a third or higher speed in order to accommodate spring 180 and to urge spool valve element 178 toward the lock-up permission position. 181 and the first line pressure P to bias the spool valve element 178 toward the lock-up release position.
_{And an} oil chamber 184 for receiving _L1 . As a result, the lock-up relay valve 98 causes the control pressure P _{SLU to} increase in the oil chamber 108 only at the third or higher speed.
To _engage (ON) according to its control pressure P _SLU
Side position. Since the second line pressure P _L2 is one pressure regulated by pressure reduction the first line pressure P _L1, the first line pressure P _L1 is at a higher pressure than the second line pressure P _L2 at all times.

An oil passage 186 is provided between the linear solenoid valve SLU and the oil chamber 144 of the lock-up control valve 100, and the control pressure P _SLU output from the linear solenoid valve SLU is applied to the solenoid relay valve. 1
The oil is supplied directly to the oil chamber 144 of the lock-up control valve 100 without passing through 70. The oil passage 186 is provided so that the lock-up control valve 100 can be operated by the control pressure P _SLU even at the second speed or lower to detect an abnormality in which the lock-up relay valve 98 is located on the engagement side. .

The shift electronic control unit 78 executes deceleration slip control or the like as deceleration engagement control in accordance with the flowchart of FIG. Of the steps in FIG. 8,
Step S1 is a throttle sensor 6 with an idle switch.
4 together with the vehicle speed sensor 66 to function as a downhill road detecting means. Step S2 functions as engagement control means during deceleration, step S5 functions as engagement control continuation means, and step S7 functions as engagement control stop means.

At step S1 in FIG. 8, it is determined whether or not the idle switch of the throttle sensor 64 is ON, that is, whether or not the accelerator pedal 50 which is operated by the driver in accordance with the required output is operated (ON operation). When the idle switch that is not depressed is turned on, if the vehicle speed V satisfies a deceleration slip condition such as a predetermined value or more in step S2,
When the lock-up clutch 24 has a predetermined target slip amount N
Linear solenoid valve SL for slip engagement with _slip ^T
By controlling the drive duty ratio DSLU of U in accordance with equation (1), deceleration slip control is performed as deceleration engagement control. In step S3, the timer CGSLP is reset.

When the determination in step S1 is NO during the deceleration slip control, that is, when the accelerator pedal 50
Is operated to turn off the idle switch, it is determined in step S4 whether or not the current traveling path of the vehicle is a downhill road. This is, for example, the actual vehicle acceleration is calculated by differentiating the vehicle speed V detected by the vehicle speed sensor 66, while the throttle valve opening TA and the vehicle speed V are used as parameters to calculate the actual vehicle acceleration on a flat road from an arithmetic expression or map set in advance. The reference acceleration is obtained, and it can be determined whether or not the vehicle is on a downhill based on whether or not the actual vehicle acceleration is greater than the reference acceleration. That is, if the actual vehicle acceleration is larger than the reference acceleration, it means that the vehicle is running at an acceleration equal to or more than the engine torque based on the throttle valve opening TA, and it is estimated that the traveling road is a downhill road with a predetermined downward gradient or more. You can.

In the case of a downhill road, step S5 is executed, and as shown in FIG. 4, the lock-up clutch 24 is accelerated or completely engaged according to the throttle valve opening TA. Since the vehicle is traveling on a downhill road, it is extremely rare that the accelerator pedal 50 is greatly depressed and suddenly accelerated, and even if the engagement control of the lock-up clutch 24 is continued, a shock due to the sudden acceleration may occur. It is unlikely to occur. FIG. 9 is a time chart showing an example of a change in the operating state of each part when the idle switch is turned ON again in a short time after the throttle valve opening TA is opened to a very small value while traveling on a downhill, and a solid line. In the case of this embodiment, the dotted line indicates that the idle switch is OFF and the lock-up clutch 2
4 is released (DSLU = 0), and in this embodiment, a large deceleration G is quickly obtained with the turning on of the idle switch.

If the road is not a downhill road, that is, if the determination in step S4 is NO on a flat road or an uphill road, step S4 is executed.
6, the timer CGSLP is set to a predetermined set value LU.
It is determined whether or not the elapsed time has exceeded the set value LUSTAT, i.e., whether or not the elapsed time since the idle switch is turned off and steps S4 and subsequent steps are executed and whether or not the elapsed time has exceeded the set value LUSTAT. Releases the lock-up clutch 24 with DSLU = 0 in step S7, executes step S8 when the set value LUSTAT is exceeded, and performs normal lock-up control in accordance with the relationship shown in FIG. FIG. 9 is a time chart showing an example of a change in the operating state of each part when the idle switch is turned off while traveling on a flat road. The solid line when the throttle valve opening TA is extremely small, and the throttle valve opening TA The dashed-dotted line at the time of rapid acceleration in which the lockup clutch 24 is released when the idle switch is turned off is the case of the present embodiment. The dotted line indicates the case where the engagement state (including slip) of the lock-up clutch 24 is continued even when the idle switch is OFF at the time of rapid acceleration when the throttle valve opening TA is large, and the throttle valve opening TA is determined by the relationship in FIG. When the lock-up clutch 24 is released by reaching the release throttle valve opening TA ₀ , a shock occurs.

In the lock-up clutch control device of this embodiment, even if the accelerator pedal 50 is depressed during deceleration slip control, if the vehicle is traveling on a downhill road, the engagement is performed in step S5. Since the control (including the slip) is continued, the deceleration G by the engine brake is continuously obtained when the throttle valve opening TA is extremely small, and large deceleration when the idle switch is turned on in a short time. G can be obtained quickly,
Drivability performance is improved. When traveling on a downhill, it is extremely rare to suddenly accelerate the vehicle by greatly depressing the accelerator pedal 50. Therefore, even if the engagement control of the lock-up clutch 24 is continued, a shock occurs due to the sudden acceleration. It is unlikely to do so.

If the vehicle is traveling on a road other than a downhill road, that is, on a flat road or an uphill road, the slip control is immediately stopped in step S7 with the depression operation of the accelerator pedal 50, and the lock-up clutch 24 is released. Therefore, when shifting from deceleration traveling to rapid acceleration, a shock caused by maintaining the engagement of the lock-up clutch 24 is prevented.

FIG. 11 relates to a manual upshift during the deceleration slip control, which is also executed by the electronic control unit 78 for shifting. In step SS1, it is determined whether or not the deceleration slip control is being performed, for example, based on the ON / OFF of the idle switch and the drive duty ratio DSLU. If the deceleration slip control is being performed, step SS2 is executed. In step SS2, whether or not the shift output is an upshift, specifically, the O / D (overdrive) switch operation of the shift lever 72 permits the O / D, that is, the fifth shift stage, and the fourth shift stage to the fifth shift stage. Switch to stage 4 → 5
It is determined whether or not a shift command has been issued. And 4 → 5
If the shift command is issued to start the drain of the hydraulic P _C0 of the clutch C0 is released side engaging element in a step SS3. The time t _{a in} the time charts of FIG. 12 and FIG.
Each time when the determination in step SS2 is YES, which is omitted in the flowchart, the engagement pressure of the lock-up clutch 24, that is, the drive duty ratio DSLU is reduced by a predetermined amount as compared with normal. FIG. 12 shows a case where the hydraulic pressure level of the engagement hydraulic pressure P _B0 of the brake B0 as the engagement side engagement element is low, and FIG. 13 shows a case where the hydraulic pressure level of the engagement hydraulic pressure P _B0 is high.

In step SS4, it is determined whether or not the shift has actually started. This is, for example, the output shaft rotation speed N
A value N _O × i _{4 obtained} by multiplying _O and the speed ratio i ₄ of the fourth speed.
The determination can be made based on whether the clutch rotation speed N _C0 has become lower than before, or whether a predetermined time has elapsed since the shift output. When the determination in step SS4 is YES, supply of the engagement hydraulic pressure P _B0 is started in step SS5. The time t _{b in} the time charts of FIG. 12 and FIG.
Each is when the determination in step SS4 is YES. Note that the supply start time of the engagement hydraulic pressure P _B0 does not necessarily need to be the same as the actual shift start, and taking into account the delay in engagement of the brake B0 due to the opening control of the ISC valve 83 in step SS7 and below. What is necessary is just to set beforehand suitably by experiment etc.

In step SS6, the clutch rotation speed N
_C0Has become equal to or less than the predetermined set value NC0TUP
No, in other words, whether it is a predetermined amount before the end of the shift
Then N _C0When ≤NC0TUP, the process proceeds to step SS7.
Return from fuel cut (F / C) (fuel
Supply restart) and install the ISC valve 83
Requires only a fixed amount to be opened. According to this, the engine
Electronic control unit 76 resumes fuel injection control.
Then, the ISC valve 83 is opened and controlled.

In step SS8, whether or not the shift has been completed is determined, for example, by multiplying the output shaft rotation speed N _{O by} the speed ratio i ₅ of the fifth speed, a value N _O × i ₅ is used as the turbine rotation speed N _T.
Is determined, or the clutch rotational speed N _C0 becomes substantially zero. And 4 → 5
When the shift is completed, step SS9 is executed, and I
It requests that the SC valve 83 be closed and permits the start of fuel cut. In accordance with this, the engine electronic control unit 76 controls the closing of the ISC valve 83 and executes the fuel cut as necessary. The time t _{c in} FIG. 12 is when the determination in step SS8 is YES.

[0045] According to such upshifting control, since opening the ISC valve 83 before the shift end is adapted to increase the output of the engine 10, a decrease in the engine rotational speed N _E accompanying the upshift engine The shock caused by the inertia of the engine 10 at the end of the shift is reduced. That is, if the output increase control of the engine 10 is not performed, the lock-up clutch 24 is subjected to the deceleration slip control. Therefore, as shown by a dotted line in FIG. Is inevitable.

When the opening control of the ISC valve 83 is performed in this manner, the engagement of the brake B0 is delayed. However, in this embodiment, since the start of the supply of the brake oil pressure P _B0 is delayed, a shock occurs when the brake B0 is engaged. There is no fear of occurring. The dotted line in FIG. 13 indicates the case where the drain of the clutch oil pressure P _C0 and the supply of the brake oil pressure P _B0 are started almost simultaneously with the shift output, and the brake oil pressure P _B0 becomes high when the drum of the clutch C0 is rotating. Then, a sudden shift stop causes a shift shock.

Although the embodiments of the present invention have been described in detail with reference to the drawings, the present invention can be embodied in other forms.

For example, in the above-described embodiment, the input shaft rotation speed N _IN of the automatic transmission 14, that is, the turbine wheel 2
A turbine rotation speed sensor 75 that detects the input shaft rotation speed N _IN of the automatic transmission 14 by detecting the rotation speed N _{T of the} second or the rotation speed of the clutch drum of the clutch C0 (clutch rotation speed) N _C0. The input shaft rotation speed N _IN is calculated by multiplying the output shaft rotation speed N _O of the automatic transmission 14 detected by the vehicle speed sensor 66 by the speed ratio i _G at that time. You may.

In the above-described embodiment, the automatic transmission 14 having five forward speeds is used.
Various other automatic transmissions may be used, such as a four-speed forward automatic transmission such as an E-automatic transmission. A continuously variable transmission such as a CVT can be used, and the present invention can be applied to a vehicle that does not have such a transmission.

In the above-described embodiment, the ISC valve 8
The control 3 is executed by the electronic control unit 76 for the engine, but may be executed by the electronic control unit 78 for transmission by mutually transmitting the input signal or the output signal.

Although not specifically exemplified, the present invention can be embodied with various modifications and improvements based on the knowledge of those skilled in the art.

[Brief description of the drawings]

FIG. 1 is a skeleton diagram illustrating a configuration of a vehicle drive device in which a lock-up clutch is controlled by a control device according to an embodiment of the present invention.

FIG. 2 is a table showing a relationship between a combination of operations of a plurality of frictional engagement devices in the automatic transmission of FIG. 1 and a shift speed established by the combination.

FIG. 3 is a block diagram illustrating a control system of the vehicle drive device of FIG. 1;

FIG. 4 is a view showing a release area, a slip control area, and an engagement area of a lock-up clutch in the embodiment of FIG. 1;

FIG. 5 is a diagram illustrating a main part of a hydraulic control circuit of FIG. 3;

6 is a diagram illustrating output characteristics of the linear solenoid valve of FIG.

7 is a characteristic diagram showing a relationship between a control pressure P _SLU and an engagement-side hydraulic pressure P _on and a release-side hydraulic pressure P _off of a lock-up clutch in the hydraulic control circuit of FIG. 5;

FIG. 8 is a flowchart illustrating lock-up control when an accelerator pedal is depressed during deceleration slip control in the embodiment of FIG. 1;

FIG. 9 is an example of a time chart showing an operation state of each part at the time of lock-up control performed according to the flowchart of FIG. 8 while traveling on a downhill road.

FIG. 10 is an example of a time chart illustrating an operation state of each unit during lock-up control performed according to the flowchart of FIG. 8 while traveling on a flat road.

FIG. 11 is a flowchart illustrating upshift control performed during deceleration slip control in the embodiment of FIG. 1;

FIG. 12 is an example of a time chart showing an operation state of each unit during upshift control performed according to the flowchart of FIG. 11;

FIG. 13 is another example of a time chart showing an operation state of each unit at the time of upshift control performed according to the flowchart of FIG. 11;

[Explanation of symbols]

 10: Engine 12: Torque converter (fluid transmission) 24: Lock-up clutch 50: Accelerator pedal (accelerator operating means) 76: Electronic control unit for engine 78: Electronic control unit for speed change 64: Throttle sensor with idle switch 66: Vehicle speed Sensor Step S1: Accelerator operation detection means Step S2: Deceleration engagement control means Step S4: Downhill road detection means Step S5: Engagement control continuation means Step S7: Engagement control stop means

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F16H 61/14

Claims (2)

(57) [Claims] 1. A lock-up clutch control device for a vehicle having a deceleration engagement control means for engaging a lock-up clutch disposed in parallel with a fluid transmission device during a predetermined deceleration traveling, wherein the required output is Accelerator operation detecting means for detecting whether an accelerator operation means operated in response to the ON operation has been operated, downhill road detecting means for detecting whether or not the current traveling path of the vehicle is a downhill road; During the engagement control by the engagement control unit, the accelerator operation detection unit detects that the accelerator operation unit has been turned ON, and the downhill road detection unit detects that the vehicle is traveling on a downhill road. A control device for a lock-up clutch for a vehicle, comprising: an engagement control continuation unit that continues the engagement control when detected. 2. The downhill road detection method according to claim 1, wherein the accelerator operation detection means detects that the accelerator operation means has been turned ON during the engagement control by the deceleration engagement control means. Control means for stopping the engagement control when the vehicle detects that the vehicle is traveling on a place other than a downhill road. apparatus.