JPH11257484A - Control device of lock-up clutch for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a slip control device for a lock-up clutch for a vehicle to prevent the generation of a feeling of physical disorder even when fuel cutoff operation is returned during control of a slip occurring during coasting running of a vehicle. SOLUTION: When it is decided by a slip control deciding means that the slip of a lock-up clutch 32 is under control, return operation from fuel cut-off through fuel cut control and 4→3 down shift operation of an automatic transmission 14 are executed in parallel by a timing control means. This constitution causes the simultaneous occurrence of the increase of vehicle acceleration G occurring due to return operation of fuel cut control and the decrease of the vehicle acceleration G occurring the 4→3 down shift operation and this increase and decrease are offset, whereby since the shock of a vehicle is relaxed owing to return of fuel cutoff operation of fuel cut control during control of a deceleration slip during coasting running of the vehicle, even during downward slope running, the occurrence of a feeling of physical disorder to a driver is suitably prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lock-up clutch control device for a vehicle.

[0002]

2. Description of the Related Art A hydraulic power 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, and an engine running in a coasting state and having a predetermined fuel cut speed. A fuel cut control unit that shuts off the fuel supply to the engine when the value exceeds the value, during coasting with the throttle valve opening closed, the slip control unit causes the lock-up clutch to slip. Slip control devices are known. For example, the apparatus described in Japanese Patent Application Laid-Open No. 2-118265 is one of them. According to such a control device, the period in which the engine speed during coasting is equal to or higher than the fuel cut speed value due to slippage of the lock-up clutch is lengthened, and fuel consumption is reduced.

[0003]

According to the above-described conventional slip control device, during the above-described slip control during coasting, the fuel cut-off operation by the fuel cut control means is terminated for some reason. When the normal fuel supply state is restored, the negative torque of the engine is sharply reduced by the return of the fuel cutoff operation, so that the decelerating action of the vehicle is suddenly eliminated and there is a disadvantage that the driver feels strange. In particular, such discomfort is noticeable when the vehicle is traveling on a downhill road.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a driver with an uncomfortable feeling even when the fuel cutoff operation is restored during slip control during coasting of a vehicle. An object of the present invention is to provide a vehicle lock-up clutch slip control device that does not generate the slip.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the gist of the present invention is to provide a hydraulic power transmission with a lock-up clutch having a lock-up clutch for directly connecting an engine and an automatic transmission. In a vehicle having
Shift control means for switching gears of the automatic transmission;
Fuel cut control means for shutting off fuel supply to the engine when the vehicle is coasting and the engine speed exceeds a predetermined value, and slip control for executing slip control of the lock-up clutch during coasting of the vehicle And (b) determining whether the slip control is being performed by the slip control means, and (b) controlling the slip control during the slip control. If it is determined by the determining means that the slip control of the lock-up clutch is being performed, a return operation from the fuel cutoff by the fuel cut control means and a downshift operation of the automatic transmission by the shift control means. And timing control means for performing the operations in parallel.

[0006]

In this manner, when the slip control determination means determines that the slip control of the lock-up clutch is being performed, the timing control means returns from the fuel cut-off control by the fuel cut control means. The operation and the downshift operation of the automatic transmission by the shift control means are performed in parallel.

[0007]

As described above, during the slip control of the coasting of the vehicle, the return operation from the fuel cutoff by the fuel cut control means and the downshift operation of the automatic transmission by the shift control means are performed in parallel. In addition, the acceleration of the vehicle by the return operation of the fuel cut control means and the deceleration of the vehicle by the downshift operation occur at the same time, thereby canceling each other. Preferably prevented.

[0008]

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 view of a vehicle power transmission device to which an 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.

[0010] The torque converter 12 is an engine 1
Pump wheel 18 connected to crankshaft 16
And a turbine wheel 22 fixed to the input shaft 20 of the automatic transmission 14 and rotated by receiving oil from the pump wheel 18, and fixed to a housing 26 which is a non-rotating member via a one-way clutch 24. Stator wheel 28
And a lock-up clutch 32 connected to the input shaft 20 via a damper 30. When the oil pressure in the release-side oil chamber 33 is higher than that in the engagement-side oil chamber 35 in the torque converter 12, the lock-up clutch 32 is disengaged. Torque is transmitted at a corresponding amplification factor. However, when the oil pressure in the engagement side oil chamber 35 is higher than that in the release side oil chamber 33, the lock-up clutch 32 is engaged, so that the input / output member of the torque converter 12, that is, the crankshaft 16 and the input The shaft 20 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 the input shaft 20, an output gear 39 that rotates together with the ring gear of the planetary gear device 38, and the differential gear device. 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, 36, 3
Some of the eight components are the four brakes B ₀ , B ₁ , B
_2, B is selectively coupled to the housing 26 by _three further one-way clutch F ₀ part three components, F _1, mutually or housing 26 and engages by its rotational direction by the F ₂ It is made to be made.

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 42 described later, and is shown in FIG. As described above, four forward speeds and one reverse speed with different speed ratios I (= rotation speed of input shaft 20 / rotation speed of counter shaft 40) are obtained. In FIG. 2, "1st",
“2nd”, “3rd”, and “O / D (overdrive)” represent the first gear, second gear, third gear, and fourth gear on the forward side, respectively. The gear ratio gradually decreases from the first gear to the fourth gear. 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.

The 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 for controlling the engagement of the lock-up clutch 32. And a hydraulic control circuit. As is well known, the shift control hydraulic control circuit includes a first solenoid valve 46 and a second solenoid valve 48 that are turned on and off by solenoids No. 1 and No. 2, respectively. As shown in FIG. 2, a clutch and a brake are selectively operated by a combination of the operations of the valve 46 and the second solenoid valve 48 to establish any one of the first to fourth gears. It is supposed to be.

The lock-up clutch control hydraulic control circuit is turned on and off by a switching electromagnetic solenoid 49 to generate a switching signal pressure P _sw, as shown in FIG. 3, for example. The clutch switching valve 5 is switched between a release side position in which the lock-up clutch 32 is released and an engagement side position in which the lock-up clutch 32 is engaged according to the switching signal pressure P _sw.
2 and the drive current I _SLU supplied from the electronic control unit 42
Generating a slip control signal pressure P _SLU corresponding to a linear solenoid valve 54, the pressure difference between the engagement side oil chamber 35 and the disengagement-side oil chamber 33 in accordance with the slip control signal pressure P _SLU output from the linear solenoid valve 54 And a slip control valve 56 for adjusting ΔP and controlling the slip amount of the lock-up clutch 32.

In FIG. 3, a pump 60 for sucking and pumping the hydraulic oil recirculated to a tank (not shown) through 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 . Also, the manual valve 70 is shifted operating lever 196 is at a R range, generates a R range pressure P _R. Then, OR valve 72, pressure actuating the brake B ₂ that engages when it is the second-speed gear stage or P
_B2 and selects either the high side of the R range pressure P _R is output.

The clutch switching valve 52 is connected to the release-side oil chamber 3.
3, an engaging port 82 communicating with the engaging oil chamber 35, an input port 84 to which the second line pressure Pl ₂ is supplied, and an engaging oil chamber when the lockup clutch 32 is released. 35, a second discharge port 88 through which the hydraulic oil in the release-side oil chamber 33 is discharged when the lock-up clutch 32 is engaged,
A supply port 90 through which part of the hydraulic oil discharged from the pressure regulating valve 66 is supplied for cooling during the engagement period of the lock-up clutch 32, a spool valve element 92 for switching the connection state of the ports, and a spool A spring 94 for urging the valve 92 toward the off-side position, a plunger 96 arranged to be able to abut on an end of the spool valve 92 on the spring 94 side, and end faces of the spool valve 92 and the plunger 96 oil chamber 100 for receiving an oil chamber 98 provided between them to exert a R range pressure P _R, the first line pressure Pl ₁ to act on the end surface of the plunger 96
And an oil chamber 102 for receiving the switching signal pressure P _sw in order to generate a thrust toward the on-side position by applying the switching signal pressure P _sw from the third solenoid valve 50 to the end face of the spool valve element 92. It has.

In the third solenoid valve 50, in a non-excited state (OFF state), the communication between the oil chamber 102 and the OR valve 72 is interrupted by a spherical valve and the oil chamber 102 is set to a drain pressure. state), the communicated between oil chamber 102 and the OR valve 72 exerts a switching signal pressure P _sw in the oil chamber 102. Therefore, when the third solenoid valve 50 is in the off state, the oil chamber 1
02, the switching signal pressure P _sw from the third solenoid valve 50 is not applied, and the spool valve 92 is turned off according to the urging force of the spring 94 and the first line pressure Pl ₁ acting on the oil chamber 100. Since the input port 84 and the first discharge port 86 communicate with each other, the oil pressure P _off in the release-side oil chamber 33 becomes lower than the engagement-side oil. The hydraulic oil in the engagement side oil chamber 35 is released from the first discharge port 86, the oil cooler 104, and the check valve 106 at the same time when the lock-up clutch 32 is released by increasing the hydraulic pressure P _on in the chamber 35. Is discharged to the drain through

On the other hand, when the third solenoid valve 50 is in the ON state, the switching signal pressure P _sw from the third solenoid valve 50 is applied to the oil chamber 102, and the spool valve element 92 applies the urging force of the spring 94. And the first line oil pressure Pl ₁ acting on the oil chamber 100, it is located at the ON side position.
Input port 84, engagement side port 82, release side port 80
And the second discharge port 88, and the supply port 90 and the first discharge port 86, respectively.
At the same time the hydraulic pressure P _on the lock-up clutch 32 is higher than the hydraulic pressure P _off in the release side oil chamber 33 of the inner is engaged, the hydraulic fluid in the release side oil chamber 33 is the second discharge port 8
8 and drain to the drain via the slip control valve 56.

[0019] The linear solenoid valve 54, the third line pressure Pl ₃ fixed to be generated in the third pressure regulating valve 68 to a pressure reducing valve to source pressure, from the electronic control unit 42 as shown in FIG. 4 A signal pressure P _SLU for slip control which increases with the drive current I _SLU is generated, and the signal pressure P _SLU for slip control is applied to the slip control valve 56. The linear solenoid valve 54 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. Reference numeral 114 denotes an urging force in the valve opening direction by an electromagnetic solenoid 118 and a spring 116, and a spring 115 and a filter. The operation is performed so that the biasing force in the valve closing direction due to the feedback pressure is balanced.

The slip control valve 56 has a line pressure port 130 to which the second line pressure Pl ₂ is supplied, a receiving port 132 for receiving hydraulic oil in the release side oil chamber 33 discharged from the second discharge port 88, A drain port 1 for discharging the hydraulic oil received in the receiving port 132
34, the receiving port 132 and the drain port 134 are made to communicate with each other, and the hydraulic oil in the release-side oil chamber 33 is discharged, so that the pressure difference ΔP (= P) between the engagement-side oil chamber 35 and the release-side oil chamber 33. The second line pressure Pl ₂ is provided in the release side oil chamber 33 by communicating between the direction toward the first position (on the right side in FIG. 3) where the _on- P _off is increased and the receiving port 132 and the line pressure port 130. And a spool valve element 136 movably provided in a direction toward a second position (the left position in FIG. 3) for reducing the ΔP, and the spool valve element 136 is moved toward the first position. A plunger 138 arranged to be able to abut against the spool valve element 136 for biasing, the plunger 138 and the spool valve element 1
And a signal pressure oil chamber 140 for receiving the slip control signal pressure P _SLU to cause the plunger 138 and the spool valve element 136 to generate thrusts in directions away from each other by causing the slip control signal pressure P _SLU to act on the plunger 138 and the spool valve 136. ,
An oil chamber 142 that receives the oil pressure P _off to cause the plunger 138 to generate a thrust in the direction toward the first position by causing the plunger 138 to act on the oil pressure P _off in the release-side oil chamber 33; Spool valve 13
6, an oil chamber 144 for receiving the oil pressure P _on to generate a thrust in the direction toward the second position on the spool valve element 136 by causing the oil pressure P _on in the engagement side oil chamber 35 to act on the spool valve element 136; A spring 146 housed in the chamber 140 and biasing the spool valve element 136 in the direction toward its second position.

Here, the plunger 138 is formed with a first land 148 and a second land 150 having sectional areas A ₁ and A ₂ that become smaller in order from the oil chamber 142 side. the third land 152 is the cross-sectional area a ₃ from the signal pressure oil chamber 140 side, the same cross-sectional area a ₄ and smaller a ₁ than its cross-sectional area a ₃ 4
Fifth lands 154, and the same cross-sectional area A ₅ and A ₁
A land 156 is formed. The cross-sectional areas of these lands have a relationship of A ₃ > A ₁ (= A ₄ = A ₅ )> A ₂ . Therefore, the clutch switching valve 52 is in the ON state, and the slip control signal pressure P _SLU is relatively small.
Is established, the plunger 138 abuts on the spool valve element 136 to operate integrally with each other, and the pressure difference Δ having a magnitude corresponding to the slip control signal pressure P _SLU.
P is formed. At this time, the pressure difference ΔP slope by Equation 2 to the slip control signal pressure P _SLU is [(A ₃ -A
₂ ) / A ₁ ]. In addition,
In Equation 2, F _s is the biasing force of the spring 146.

[0022]

[Equation 1] A ₁ · P _off ≧ A ₂ · P _SLU

[0023]

ΔP = P _on −P _off = [(A ₃ −A ₂ ) / A
₁ ] P _SLU −F _s / A ₁

However, when the slip control signal pressure P _SLU becomes larger than a predetermined value P _A , the relationship shown in Expression 3 is established. The predetermined value P _A is a value that is determined in advance so as to obtain a change range ΔP _slip of the pressure difference ΔP of a sufficient magnitude necessary for the slip control of the lock-up clutch 32. Each cross-sectional area and the like are set so that the relationship shown in Expression 3 is satisfied when the pressure P _SLU becomes the value P _A. For this reason, the plunger 138 and the spool valve element 136 are separated from each other, and the spool valve element 136 is operated so that Equation 4 is satisfied. However, in a state in which the spool valve element 136 is operated so that Equation 4 is satisfied, the slip control valve 56
Since the receiving port 132 and the drain port 134 are configured to communicate with each other, the hydraulic pressure P _off in the release-side oil chamber 33 further decreases and becomes the atmospheric pressure, so that ΔP = P _on Complete engagement is established. The solid line in FIG. 5 shows a change characteristic of the pressure difference ΔP obtained by the operation of the slip control valve 56 configured as described above with respect to the slip control signal pressure P _SLU .

[0025]

[Equation 3] A ₁ · P _off <A ₂ · P _SLU

[0026]

[ _Equation 4] A ₃ · P _SLU = A ₄ · P _on + F _s

As shown in FIG. 5, when the slip control signal pressure P _SLU becomes small and becomes equal to or less than the value P _B that satisfies Equation 5, the pressure difference ΔP = 0, so that the switching valve 52 Is in the ON state, the lock-up clutch 32 is in the released state.

[0028]

[Equation 5] A ₃ · P _on > A ₃ · P _SLU

Returning to FIG. 1, the vehicle has an engine electronic control for executing a fuel injection control, a fuel cut control, an ignition timing control, etc., for controlling a fuel injection amount by a fuel injection valve (not shown) according to an intake air amount. An apparatus 178 is provided. This fuel cut control, the throttle valve opening TA becomes the engine speed N _e is fuel-cut rotational speed N _{cu t} or more previously set during deceleration coasting is less than a predetermined value close to zero, for example, the fuel injection valve Is closed, the fuel supply to the engine 10 is shut off. This interruption of the fuel supply is intended to improve fuel economy.

The electronic control unit 42 includes a CPU 182, an RO
M184, RAM186, interface not shown
A so-called microcomputer consisting of
Is provided in the intake pipe of the engine 10 and is not shown.
Throttle valve 1 that is opened and closed by operating the accelerator pedal
Throttle sensor 188 for detecting the opening of 87, engine
Engine speed sensor 1 for detecting the speed of engine 10
90, detecting the rotation speed of the input shaft 20 of the automatic transmission 14
Input shaft rotation sensor 192, counter of automatic transmission 14
Counter shaft rotation sensor 19 for detecting rotation speed of shaft 40
4. Clutch C ₀ (Not shown)
Switch C₀ Operation position of rotation sensor and shift operation lever 196
Position, that is, any of L, S, D, N, R, and P ranges
From the operation position sensor 198 for detecting the
Signal representing the valve opening degree TA, the engine speed N_e(Pong
Wheel speed N_PThat is, the lock-up clutch 3
2, the input shaft rotation speed N)_in
(Turbine wheel rotation speed N _TI.e. lock-up
A signal representing the output rotation speed of the latch 32) and the vehicle speed V
Output shaft rotation speed N_outSignal representing the clutch C₀ 
Rotation speed N_C0Signal indicating the shift operation lever 196
Operation position P_sSignals that indicate
ing. The CPU 182 of the electronic control unit 42
Using the temporary storage function of the AM 186,
Processing the input signal according to the program stored in 4,
Shift control and lock-up clutch of automatic transmission 14
The engagement control of No. 32 is performed according to a main routine (not shown).
The first solenoid valve 46, the second solenoid valve 48, the third solenoid valve
50 and the linear solenoid valve 54, respectively.
You.

In the above-described shift control, the data is stored in the ROM 184 in advance.
From the multiple types of shift diagrams remembered,
The corresponding shift diagram is selected, and the vehicle travel is determined from the shift diagram.
Line state, for example, throttle valve opening TA and output shaft rotation speed
Degree N_outIs determined based on the vehicle speed calculated from
The first solenoid valve is determined so that the transmission gear stage is obtained.
When the second solenoid valve 48 is driven, the automatic change is performed.
Clutch C of gearbox 14 ₀ , C₁ , C_Two , And brake
B₀ , B₁ , B_Two , B_Three Operation is controlled and the forward four-stage
One of the gears is established.

The engagement of the lock-up clutch 32 is controlled, for example, in the second gear, the third gear, and the fourth gear.
This engagement control is performed during traveling in a high gear stage. In the engagement control, the traveling state of the vehicle, such as the output shaft rotation, is determined based on the relationship shown in FIG. Based on the speed (vehicle speed) _Nout and the throttle valve opening TA, it is determined whether the lock-up clutch 32 is in the release area, the slip control area, or the engagement area. This relationship is selected from a plurality of types of relationships stored in advance according to the actual gear position. In FIG. 6, the connection effect is maintained on the release region side and the low throttle valve opening side of the boundary line between the engagement region and the release region in order to improve fuel efficiency as much as possible without impairing drivability. In addition, a slip control region is provided for absorbing the torque fluctuation of the engine 10 while performing the control.

When it is determined that the running state of the vehicle is within the engagement region shown in FIG. 6, the third solenoid valve 50 is excited to turn on the clutch switching valve 52, and at the same time the linear solenoid valve 54 is turned on. since the drive current I _SLU for 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 area shown in FIG.
Is de-energized and the clutch switching valve 52 is turned off, so that the drive current I to the linear solenoid valve 54 is
_The lock-up clutch 32 is released regardless of the _SLU . When it is determined that the running state of the vehicle is within the slip control region shown in FIG. 6, the third solenoid valve 50 is excited and the clutch switching valve 52 is turned on, and at the same time,
The drive current I _SLU for the linear solenoid valve 54 is adjusted, for example, according to the control formula I _SLU = _{IF / F} + _{IF / B.} That is, for example, the deviation ΔN _slip between the steady-state target slip rotation speed N _slip ^T determined from the relationship shown in FIG. 7 and the actual slip rotation speed N _slip (= N _e −N _T ).
(= N _slip −N _slip ^T ) A feedback control amount _{IF / B} based on a PID feedback control formula set so as to eliminate, and a feedforward control amount stored in a map in advance to improve control response. By adding the _{IF / F} , a control amount, that is, a drive current _ISLU is calculated and output.

In the engagement control of the lock-up clutch 32, the engine rotation speed _Ne is increased and the fuel cut region is expanded in the coasting state of the vehicle in which the throttle valve opening TA is substantially zero. The deceleration slip control is executed. In this deceleration slip control, in the same manner as described above, the target slip rotational speed N _slip ^T and the actual slip rotational speed N feedback control amount from the set PID feedback controlled so that the deviation .DELTA.N _slip is eliminated with the _slip I _{F / B} and the feedforward control amount I _{F / F} stored in advance in the map to improve the control response, add the control amount, that is, the drive current I _SLU.
Is calculated and output. The fuel cut control by the engine electronic control device 178 is performed after the engagement of the engagement torque due to the slippage of the lock-up clutch 32, so that a predetermined delay time elapses after the start of the deceleration slip control. It is to be started later.

FIG. 8 is a functional block diagram for explaining a main part of the control function of the electronic control unit 42 according to the present invention. In the figure, a torque converter 12 with a lock-up clutch 32 is interposed between an engine 10 and an automatic transmission 14. Fuel cut control means corresponding to the engine electronic control unit 178 200, the engine 10 is in the coasting period and the engine rotational speed N _e throttle valve opening TA is substantially zero is fuel-cut rotational speed N _{cu t} or Shut off the fuel supply to. Slip control means 202 corresponding to the engagement control routine, the coasting period the accelerator pedal is returned to the idle position, that is the non-accelerated position, to expand the operation time of the fuel cut by increasing the engine rotational speed N _e Therefore, the deceleration slip control of the lock-up clutch 32 is started. The shift control means 216 switches the gear position of the automatic transmission 14. If it is determined by the slip control determination means 218 that the lock-up clutch 32 is under slip control, the timing control means 220 causes the fuel cut control means 200 to perform a return operation from fuel cutoff and the shift control means 216. And the downshift operation of the automatic transmission 14 is performed in parallel.

FIG. 9 shows a control routine for preventing an uncomfortable feeling due to the return of the fuel cut control during the deceleration slip control, that is, a generation of a shock and a feeling of missing during deceleration during the control operation of the electronic control unit 42. ing.
In the figure, in step SC1 corresponding to the slip control in-operation determining means 218, it is determined whether or not deceleration slip control is in progress. While the routine is terminated if the determination at step SC1 is negative, the If so, the engine rotational speed in step SC2 N _e is preset fuel cut return rotational speed of the guard value N
_It is determined whether it is larger than _FCRTN . In this step SC2, it is also determined in parallel whether or not the fuel cut control executed by the engine electronic control device 178 has been restored for some reason.

If a negative decision is made in step SC2, the deceleration slip control of the lock-up clutch 32 is stopped in step SC13, and the flow proceeds to step SC1.
In step 4, the content of the flag F3 is cleared to "0". In step SC15, the fuel cutoff by the fuel cut control is completely restored, and in step SC16, the content of the flag F4 is set to "FF". When the content of the flag F3 is "0", the flag F3 indicates the deceleration slip control state in the fourth gear, and the content is "1".
Indicates the state from the time of the downshift output from the fourth gear to the third gear to the actual start of the downshift, and when the content is “2”, the fourth gear is 3 shows a state from the start of the downshift to the third gear stage until the end of the shift. The flag F4 indicates that the fuel is being cut when the content is "0", indicates that the fuel is being returned from the fuel cut when the content is "1", and indicates that the content is "FF" when the content is "FF". Shows the state after the completion of the return from the fuel cut.

If the determination in step SC2 is affirmative, it is determined in next step SC3 whether or not the content of the flag F3 is "2". In step SC4, the content of the flag F3 is "1". Is determined. While the vehicle is traveling in the fourth gear, in which the deceleration slip control is being executed, the determinations in steps SC3 and SC4 are both negative. Therefore, in step SC5, the output shaft rotational speed N _out is set to 4 → It is determined whether or not the rotation speed N _{SLIP43 at} which the shift output of three downshifts is performed has _fallen below. This N _SLIP43 is the throttle valve opening T
The vehicle speed is higher than the 4 → 3 shift point when A is zero, and is set to a value higher than or substantially higher than the fuel cut rotation speed N _cut by a predetermined value. Therefore,
The shift down may be performed when the fuel cut control is restored, and the fuel cut control may be restored when the shift down is performed.

If the determination in step SC5 is negative, this routine is terminated. Thus, the above steps are repeatedly executed, and while the coasting continues, the vehicle speed V decreases and the determination in step SC5 is affirmed. Then, in step SC6, the shift output for executing the downshift from the fourth gear to the third gear is output to the automatic transmission 14.
Be sent to T ₁ of FIG. 10 shows this state. Then, after the content of the flag F3 is set to "1" in step SC7, in step SC8, the rotational speed N _C0 of the clutch C ₀ is changed to the shift start determination reference value N
_It is determined whether it is larger than _43D . The shift start determination reference value N _43D is a value for determining that the 4 → 3 downshift has substantially started, for example, 50 rp.
A value of about m is adopted. In the downshift from the fourth gear to the third gear, the brake B ₀ is released and the clutch C ₀ is engaged, so that the 4 → 3 shift down is substantially performed based on the start of rotation of the clutch C _0. The start is confirmed.

If the determination at step SC8 is negative, this routine is terminated. However, since the content of the flag F3 is set to "1" as described above, the routine proceeds to step SC4 in the next control cycle. The judgment is affirmed, and step SC8 is executed again. While the above steps are repeatedly executed, if the 4 → 3 downshift is actually started, the determination in step SC8 is affirmed, and the control for returning to the fuel cut control is started in the subsequent step SC9. T ₂ of FIG. 10 shows this state. Step SC5 and Step SC5
Reference numeral 8 corresponds to the timing control means 220 for executing the 4 → 3 shift down and the return of the fuel cut control in parallel.

Then, in step SC10, the content of the flag F3 is set to "2" and the flag F4 is set.
Is set to "1", the return control of the fuel cut control is continued in step SC11, and the fuel injection amount is gradually increased. Then, in step SC12, the output shaft rotation speed _Nout and the rotation of the clutch _C0 are rotated. Speed N
_It is determined whether or not the difference from _C0 (N _out -N _C0 ) has _fallen below a predetermined reference rotation speed N _SLIPEND . The determination reference rotation speed N _SLIPEND is determined based on the fact that the rotation speed N _C0 of the clutch C ₀ approaches the output shaft rotation speed N _out by executing the downshift to the third speed.
This is a value set in advance in consideration of the responses to start the end of the deceleration slip control and the return of the fuel cut control at time Δt before the achievement of the speed gear.

Initially, the determination in step SC12 is denied, and this routine is terminated. However, since the content of the flag F3 is set to "2" as described above, step SC3 in the next control cycle is executed. Is affirmed, and step SC11 and subsequent steps are executed again. While the above steps are repeatedly executed, if the rotational speed N _C0 of the clutch C ₀ increases due to the execution of the 4 → 3 shift down, the judgment at the step SC12 becomes affirmative. If the determination in step SC12 is affirmative,
In step SC13, the deceleration slip control is stopped. In step SC14, the content of the flag F3 is cleared to "0". In step SC15, the fuel cut control is completely restored. In step SC16, the content of the flag F4 is set to "FF". Set. This state is indicated by t ₃ in FIG. Then, after a predetermined time delay Δt, the third speed is achieved, and at the same time, the elimination of the transmission torque by stopping the deceleration slip control and the recovery of the engine output torque by returning the fuel cut control are substantially simultaneously ended. Can be T ₄ in FIG. 10 shows this state.

As described above, according to the present embodiment, when it is determined in step SC1 corresponding to the slip control determining means 218 that slip control of the lock-up clutch 32 is being performed, the timing control means is determined. 22
By the steps SC5 and SC8 corresponding to 0, the return operation from the fuel cutoff by the fuel cut control and the 4 → 3 downshift operation of the automatic transmission 14 are performed in parallel. As a result, an increase in the vehicle acceleration G caused by the return operation of the fuel cut control and a decrease in the vehicle acceleration G caused by the 4 → 3 downshift operation are simultaneously generated and cancel each other, so that the vehicle coasts. The shock of the vehicle caused by the return of the fuel cut-off operation of the fuel cut control during the deceleration slip control is reduced, so that, for example, it is preferable to give the driver a sense of incongruity even while traveling downhill. Is prevented.

According to the present embodiment, when the fuel cut control executed by the engine electronic control unit 178 is terminated for some reason, the deceleration slip control is immediately performed by steps SC2 and SC13. since the aborted, there is an advantage that due to the increase in the engine rotational speed N _e by the end of the fuel cut control one o'clock engagement of the lock-up clutch 32 is prevented.

Conventionally, as shown in FIG. 11, for example, in order to prevent an uncomfortable feeling such as a loss of deceleration due to a return operation of the fuel cut control executed during the deceleration slip control, the fuel cut control is restored. Before the operation, the slip amount of the lock-up clutch 32 may be increased. In such a conventional case, FIG.
As shown in A, the deceleration (negative value of the acceleration G) suddenly decreased, causing a sense of incongruity, and the fuel cut period was shortened by the amount shown in the T section, resulting in a decrease in fuel efficiency. On the other hand, according to the present embodiment, the deceleration slip control can be executed while the slip amount is small (for example, about 50 rpm) until immediately before the fuel cut rotation speed N _cut , so that the fuel cut region is limited to the region indicated by T in FIG. Sustainability is improved, fuel efficiency is improved, and acceleration is smoothed for the above-mentioned reason.

According to the present embodiment, when the shift output of the 4 → 3 downshift having a long response time is output first and it is determined in step SC8 that the shift has been substantially started, Since the return of the fuel cut control having a short response time is executed in step SC9, there is an advantage that the occurrence of deceleration due to downshifting and the occurrence of acceleration due to fuel cut control are substantially matched.

According to the present embodiment, step SC1
Since the return of the fuel cut control is gradually executed by the step 1, the acceleration G of the vehicle is increased due to the increase in the fuel supply over the entire execution time of the 4 → 3 downshift that reduces the acceleration G of the vehicle. There is an advantage that the acceleration G of the vehicle becomes smooth regardless of the return of the fuel cut control or the downshift.

Further, according to the present embodiment, the timing before the predetermined time before the shift of the 4 → 3 downshift is substantially ended is determined in step SC12, and the fuel cut control and the deceleration slip control are ended almost simultaneously. because it is the increase in the engine rotational speed N _e by the end of the drop and the fuel cut control of the engine rotational speed N _e by the end of the deceleration slip control is generated at the same time. Thus, dips is eliminated in the engine rotational speed N _e occur if or shock due to transient engagement of the lock-up clutch 32, the end of the deceleration slip control is preceded occur if the end of the fuel cut control is preceded .

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, in the embodiment of FIG. 9 described above, if it is determined in step SC12 that the third gear is to be established, the end of the deceleration slip control and the return of the fuel cut control are started simultaneously. However, when the response characteristics of the two are different, they may be started at independent timings.

Further, the clutch switching valve 52 of the above-described embodiment is used.
Was turned on and off in accordance with the switching signal pressure P _sw supplied to the oil chamber 102 from the third solenoid valve 50, but was turned on and off in accordance with the slip control signal pressure P _SLU output from the linear solenoid valve 54. Is also good. In this case, when the slip control signal pressure P _SLU falls below the value P _B shown in FIG.
When the slip control signal pressure P _SLU exceeds its value P _B , the spool valve 92 of the clutch switching valve 52 is turned on against the urging force of the spring 94. , The urging force of the spring 94, the pressure receiving area of the spool valve element 92, and the like are set.

Although the torque converter 12 with a lock-up clutch has been described in the above embodiment, a fluid coupling with a lock-up clutch may be used. In short, any hydraulic transmission having a lock-up clutch may be used.

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 diagram illustrating a main configuration of a hydraulic control circuit of FIG. 1;

FIG. 4 is a view showing output characteristics of the linear solenoid valve of FIG. 3;

5 is a characteristic of a slip control valve provided in the hydraulic control circuit of FIG. 3, 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. 6 is a diagram illustrating a relationship between a running state of the vehicle and an engaged state of a lock-up clutch, which is stored in the electronic control device of FIG. 1;

7 is a diagram illustrating a relationship stored in the electronic control device of FIG. 1 for determining a target slip rotation speed in a steady state.

FIG. 8 is a functional block diagram illustrating a main part of a control function of the electronic control device of FIG. 1;

FIG. 9 is a flowchart illustrating the control operation of the embodiment of FIG. 8 in detail.

FIG. 10 is a time chart illustrating a control operation according to the embodiment of FIG. 9;

FIG. 11 is a diagram corresponding to FIG. 10 in a conventional control device.

[Explanation of symbols]

 10: engine 14: automatic transmission 32: lock-up clutch 200: fuel cut control means 202: slip control means 216: shift control means 218: slip control determination means 220: timing control means

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI // F16H 59:34 59:42 63:12

Claims (1)

[Claims] 1. A vehicle having a lock-up clutch-equipped fluid transmission device having a lock-up clutch for directly connecting an engine and an automatic transmission, a shift control means for switching a gear position of the automatic transmission, and coasting. A fuel cut control unit that shuts off fuel supply to the engine when the vehicle is in a state and the rotation speed of the engine exceeds a predetermined value; and a slip control unit that performs a slip control of the lock-up clutch during coasting of the vehicle. A control device for a vehicle lock-up clutch of the type comprising: a slip control-in-judgment means for judging that the slip control is being performed by the slip control means; and If it is determined that the slip control is being performed, the fuel cut control is performed. Returning operation and the shift control means according to the automatic transmission downshift operation and parallel to a timing control means for implementation, locking those containing vehicle up clutch slip control system from the fuel cutoff by stage.