JP4069678B2 - Vehicle lock-up clutch control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a lockup clutch incorporated in a drive system of a vehicle such as an automobile, and more particularly to a lockup clutch control device.
[0002]
[Prior art]
As one of control devices for controlling a lock-up clutch incorporated in a torque converter in a drive system of a vehicle such as an automobile, for example, as described in Japanese Patent Application Laid-Open No. 10-220572 relating to the application of the present applicant, When the vehicle operating range determined by the throttle opening as the engine load factor and the vehicle speed is within the preset lock-up clutch engaging range, the lock-up clutch is engaged and the vehicle operating range is set to the preset lock-up range. 2. Description of the Related Art A lock-up clutch control device configured to release a lock-up clutch when in a clutch release region is conventionally known.
[0003]
Generally, a lockup clutch is configured to be engaged and released by controlling a differential pressure between an engagement side pressure chamber and a release side pressure chamber. The clutch control device includes a mode switching means having an engagement mode for setting the differential pressure in the engagement direction of the lockup clutch and a release mode for setting the differential pressure in the release direction of the lockup clutch; Differential pressure adjusting means for adjusting the size, the mode switching means is set to the engagement mode, and the differential pressure adjusting means increases or decreases the differential pressure to engage and release the lock-up clutch, and mode switching The lockup clutch is maintained in the released state by setting the means to the release mode.
[0004]
[Problems to be solved by the invention]
As described above, the fuel consumption can be improved by controlling the engagement and disengagement of the lock-up clutch in accordance with the driving region of the vehicle. In particular, the transmission incorporated in the drive system of a vehicle such as an automobile is a continuously variable transmission. In order to further improve the fuel efficiency, the vehicle operating state determined based on parameters other than the throttle opening and the vehicle speed is determined even when the vehicle operating region is in the lockup clutch release region. It is conceivable to engage the lock-up clutch when the vehicle is in a specific operating state to be engaged.
[0005]
However, when the driving state of the vehicle changes between a specific driving state and a state other than the specific driving state, the same as when the driving range of the vehicle changes between the engagement region and the release region. When the lock-up clutch is engaged and released by the control, there is a problem that a shock occurs due to a rapid decrease in the power transmitted by the lock-up clutch, particularly when the lock-up clutch is released.
[0006]
The present invention has been made in view of the above-described problems in the conventional lock-up clutch control device, and the main problem of the present invention is that the driving state of the vehicle is other than the specific driving state rather than the specific driving state. When the state changes to the state, the release control of the lockup clutch is controlled in a manner suitable for the change, thereby preventing a shock from being generated when the lockup clutch is released.
[0007]
    [Means for solving the problem]
  According to the present invention, the above-mentioned main problem is that according to the present invention, the lock-up clutch is engaged in a predetermined operation region, and the lock is applied in a region other than the predetermined operation region. The vehicle lock-up clutch control device for releasing the up-clutch is used to engage the lock-up clutch when the vehicle driving state is in a specific vehicle driving state in a region other than the predetermined driving region.,in frontIf the vehicle is in a driving condition other than the specified driving range,From the specific vehicle driving stateWhen it becomes a state other than the specific vehicle driving stateDetermining whether the lockup clutch has a torque transmission capacity, and when the lockup clutch has a torque transmission capacity,When the operating area is changed from the predetermined operating area to an area other than the predetermined operating areaMore gently than the release of the lock-up clutchThis is achieved by a vehicle lockup clutch control device that releases the lockup clutch.
[0008]
  According to the present invention, in order to effectively achieve the main problems described above,During the gentle release control of the lock-up clutchWhen the vehicle driving state becomes the specific vehicle driving stateOrWhen the driving area of the vehicle becomes the predetermined driving areaIsThe lock-up clutchEngage(Structure of claim 2).
[0009]
According to the present invention, in order to effectively achieve the main problem described above, in the configuration of claim 1 or 2, the lockup clutch is provided between the engagement side pressure chamber and the release side pressure chamber. The vehicle lockup clutch control device is configured to be engaged and disengaged by controlling the differential pressure of the vehicle, and the vehicle lockup clutch control device sets the differential pressure in the engagement direction of the lockup clutch and the difference. A mode switching means having a release mode for setting the pressure in the release direction of the lock-up clutch, and a differential pressure adjusting means for adjusting the magnitude of the differential pressure, and in a region other than the predetermined operating range. When the vehicle driving state becomes a state other than the specific vehicle driving state, the mode switching means is set to the engagement mode, and the differential pressure adjusting means reduces the magnitude of the differential pressure. With releasing the click-up clutch configured to be the lock-up clutch is released to maintain the mode switching means to said engaging mode (the third aspect).
[0010]
    [Effects and effects of the invention]
  According to the configuration of claim 1, the lock-up clutch is engaged when the vehicle driving state becomes a specific vehicle driving state in a region other than the predetermined driving region., PlaceIf the vehicle is in a state other than the regular driving range,From a specific vehicle driving conditionWhen it becomes a state other than a specific vehicle driving state,It is determined whether or not the lockup clutch has torque transmission capacity. When the lockup clutch has torque transmission capacity,When the operating area is changed from the predetermined operating area to an area other than the predetermined operating areaGentler than releasing the lock-up clutchSince the lock-up clutch is released,In areas other than the specified operating areaThe vehicle driving state has changed to a state other than a specific vehicle driving state.In some cases, the lockup clutch has torque transmission capacitySometimes when the lock-up clutch is releasedDue to the sudden decrease in power transmitted by the lockup clutchShockcertainlyCan be reducedWhen the lockup clutch has no torque transmission capacity, the lockup clutch can be released quickly.The
[0011]
  According to the configuration of claim 2 above,During gentle release control of the lock-up clutchVehicle driving status is a specific vehicle driving conditionStateWhenOrThe operating area is the predetermined operating area.In the areaWhenIsLock-up clutchIs engagedSo lockup clutchReduces the time it takes to engage,Lock-up clutchQuickly engageCan.
[0012]
According to the third aspect of the present invention, the lockup clutch is configured to be engaged and released by controlling the differential pressure between the engagement side pressure chamber and the release side pressure chamber. The lockup clutch control device includes a mode switching means having an engagement mode for setting the differential pressure in the engagement direction of the lockup clutch and a release mode for setting the differential pressure in the release direction of the lockup clutch, and the differential pressure Differential pressure adjusting means for adjusting the size of the vehicle, and when the vehicle driving state is in a state other than a specific vehicle driving state in a region other than the predetermined driving region, the mode switching unit is set to the engagement mode. The lockup clutch is released by setting and reducing the magnitude of the differential pressure by the differential pressure adjusting means, and the mode switching means is set to the engagement mode even when the lockup clutch is released. Since lifting, shock due to being switched to the release mode from engagement mode by the mode switching means can be reliably prevented from occurring.
[0013]
[Preferred embodiment of the problem solving means]
  According to one preferred embodiment of the present invention, the above claim 1Any one of 3In this configuration, the lock-up clutch control device is configured to determine that it is within the predetermined operating range when the engine load factor and the vehicle speed are within the predetermined range (preferred aspect 1).
[0014]
  According to another preferred embodiment of the present invention, the above claim 1Any one of 3Alternatively, in the configuration of the preferred aspect 1 described above, the lockup clutch control device is configured to determine that the vehicle operation state is a specific vehicle operation state when the vehicle is in a start or reacceleration state (preferred aspect 2). ).
[0015]
According to another preferable aspect of the present invention, in the configuration of the preferable aspect 2, the lockup clutch control device is operated when the driver does not perform a braking operation and the driver is willing to accelerate. It is configured to determine that the vehicle driving state is in a specific vehicle driving state (preferred aspect 3).
[0017]
  According to another preferred embodiment of the invention, the above claimsAny one of 1 to 3In the configuration of the lockup clutch control deviceWhereIf the vehicle is in a state other than the regular driving range,From a specific vehicle driving conditionIf the lockup clutch has no torque transmission capacity even when the vehicle is in a state other than a specific vehicle driving state, the lockup clutch in the state where the driving region has changed from the predetermined driving region to a region other than the predetermined driving region. It is configured to release the lockup clutch as quickly as in the case of release (preferred embodiment4).
[0018]
DETAILED DESCRIPTION OF THE INVENTION
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments (hereinafter simply referred to as embodiments) of the present invention will be described in detail below with reference to the accompanying drawings.
[0019]
FIG. 1 is a skeleton diagram showing a vehicle power transmission device to which an embodiment of a lockup clutch control device according to the present invention is applied, and FIG. 2 is a lockup clutch incorporated in a torque converter of the power transmission device shown in FIG. It is explanatory drawing which shows the hydraulic circuit which controls the engaging force of. For simplification purposes, only the upper half of the torque converter and the forward / reverse switching device is shown in FIG. 1, and only the upper half of the torque converter is shown in FIG.
[0020]
In FIG. 1, a power transmission device 10 is configured to be suitable for a horizontal FF (front engine / front drive) vehicle, for example, and includes an engine 12 that is an internal combustion engine as a driving power source. . The output of the engine 12 is transmitted to the differential gear device 22 via the torque converter 14, the forward / reverse switching device 16, the belt-type continuously variable transmission mechanism (CVT) 18, and the reduction gear device 20, and is further shown in FIG. It is transmitted to the left and right drive wheels 24L, 24R via a pair of universal joints that are not provided.
[0021]
The torque converter 14 includes a pump impeller 14p connected to the crankshaft 12a of the engine 12, a turbine impeller 14t connected to the forward / reverse switching device 16 via the turbine shaft 34, and a housing via a one-way clutch 14c. It has a general configuration having a stator 14s rotatably supported by a non-rotating member, and transmits the power of the engine 12 to the forward / reverse switching device 16 via a fluid.
[0022]
A lock-up clutch (direct coupling clutch) for connecting the pump impeller 14p, which is an input rotating member, and the turbine impeller 14t, which is an output rotating member, together so that they can be integrally rotated with each other. ) 26 is provided. The lock-up clutch 26 is disposed between the engine 12 and the belt-type continuously variable transmission mechanism 18 in a power transmission path from the engine 12 to the left and right drive wheels (for example, front wheels) 24L and 24R. It is connected in series with the type continuously variable transmission mechanism structure 18.
[0023]
In the illustrated embodiment, the forward / reverse switching device 16 is constituted by a double pinion type planetary gear device. The turbine shaft 34 of the torque converter 14 is connected to the sun gear 16s, and the belt type continuously variable transmission mechanism 18 is connected. The input shaft 36 is connected to the carrier 16c. When a shift lever (not shown) is set to a forward travel range such as the D, 2, L range, etc., a hydraulic forward clutch 38 disposed between the carrier 16c and the sun gear 16s becomes a hydraulic control circuit. 39, the forward / reverse switching device 16 rotates integrally with the input shaft 36, whereby the turbine shaft 34 is directly connected to the input shaft 36. It is transmitted to the drive wheels 24R and 24L via the step transmission mechanism structure 18 and the like.
[0024]
On the other hand, when the shift lever is set to the reverse travel range which is the R range, the hydraulic reverse brake 40 disposed between the ring gear 16r and a non-rotating member such as a housing is controlled by the hydraulic control circuit 39. As a result, the ring gear 16r is connected to the non-rotating member, and the forward clutch 38 is released by being controlled by the hydraulic control circuit 39, so that the input shaft 36 rotates in the direction opposite to the turbine shaft 34. Thus, the drive force in the reverse direction is transmitted to the drive wheels 24R and 24L via the belt type continuously variable transmission mechanism structure 18 and the like. In the illustrated embodiment, as will be described later, the forward clutch 38 is used as a starting clutch as required.
[0025]
The belt type continuously variable transmission mechanism 18 includes an input side variable pulley device 42 having a variable effective diameter provided on the input shaft 36, an output side variable pulley device 46 having a variable effective diameter provided on the output shaft 44, and And the transmission belt 48 wound around the V groove of the variable pulley devices 42 and 46, and the frictional force between the transmission belt 48 functioning as a power transmission member and the wall surface of the V groove of the variable pulley devices 42 and 46. Power is transmitted through the.
[0026]
The input-side variable pulley device 42 has an input-side hydraulic cylinder 42c for changing the V groove width, that is, the winding diameter (effective diameter) of the transmission belt 48, and the hydraulic fluid 42 supplied to and discharged from the hydraulic cylinder 42c. The oil pressure Pa is controlled by the oil pressure control circuit 52, whereby the V groove width of the variable pulley device 42 is changed to change the winding diameter of the transmission belt 48, and the gear ratio γ (= input side rotation speed Nin / output side rotation). The speed Nout) is continuously changed steplessly.
[0027]
Similarly, the output side variable pulley device 46 has an output side hydraulic cylinder 46c for changing the V groove width, and the hydraulic pressure Pb in the hydraulic cylinder 46c is also regulated by the hydraulic control circuit 52, whereby the transmission belt 48 is adjusted. The tension of the transmission belt 48 is adjusted by adjusting the clamping force of the output-side variable pulley device 46 against the transmission belt 48, and the transmission belt 48 is prevented from sliding with respect to the variable pulley devices 42 and 46. The hydraulic control circuits 39 and 52 are controlled by the electronic control unit 54.
[0028]
As shown in detail in FIG. 2, the lock-up clutch 26 is disposed opposite to the inner surface of the front cover 62 connected to the crankshaft 12a of the engine 12, and contacts the inner surface of the front cover 62 by hydraulic pressure. It is configured to be separated. The oil chamber on the front cover 62 side with respect to the lockup clutch 26 is a release side oil chamber 64, and the oil chamber on the opposite side to the release side oil chamber 64 with respect to the lockup clutch 26 is an engagement side oil chamber 66, The hydraulic pressure in the release side oil chamber 64 and the engagement side oil chamber 66 is controlled by a hydraulic pressure control circuit 68 shown in FIG.
[0029]
The lock-up clutch 26 is separated from the inner surface of the front cover 62 by being supplied with hydraulic pressure (release pressure) to the release-side oil chamber 64 and discharged from the engagement-side oil chamber 66 (unlocked). When the hydraulic pressure (engagement pressure) is supplied / discharged in the opposite direction, it is pressed against the inner surface of the front cover 62 to enter the engaged state (lock-up state). Further, the differential pressure between the release side oil chamber 64 and the engagement side oil chamber 66 is appropriately controlled, so that the lockup clutch 26 is brought into contact with the front cover 62 in a sliding state, and so-called slip control is performed. Is called.
[0030]
In FIG. 2, the hydraulic control circuit 68 includes a linear solenoid valve 70, and the linear solenoid valve 70 receives a modulator pressure Pmodu obtained by regulating the line pressure as a drive current input from the electronic control unit 54. The pressure is adjusted according to the (duty ratio), and the adjusted signal pressure Plin is output to the lockup control valve 72. The lockup control valve 72 is a pressure regulating valve that regulates the hydraulic pressure regulated by a secondary regulator valve (not shown) as a source pressure and outputs it to the lockup relay valve 74. The signal pressure Plin is a spring for the spool. It is input on the opposite side to 76.
[0031]
Further, the hydraulic pressure Poff of the release side oil chamber 64 is supplied to the same end side as the signal pressure Plin, and the hydraulic pressure Pon of the engagement side oil chamber 66 is supplied to the same side as the spring 76. Accordingly, the lock-up control valve 72 appropriately sets the pressure adjustment level according to the hydraulic pressures Plin, Poff, Pon and the spring force of the spring 76, and outputs the hydraulic pressure corresponding to the pressure adjustment level.
[0032]
The lock-up relay valve 74 is a valve that performs a switching operation by causing the line pressure Pline selectively supplied by the solenoid valve 75 to act on the end opposite to the spring 78 with respect to the spool, and is controlled by a secondary regulator valve. A first port 80 to which the regulated regulator pressure Pcl is supplied, a second port 82 to which the hydraulic pressure output from the lockup control valve 72 is supplied, and a third port connected to the release-side oil chamber 64. Port 84 and a fourth port 86 connected to the engagement-side oil chamber 66.
[0033]
The state of the lockup relay valve 74 shown in FIG. 2 is a state in which the solenoid valve 75 is controlled to be OFF, the first port 80 is connected to the third port 84, and the regulator pressure Pcl is released. The oil is supplied to the oil chamber 64, the second port 82 is closed, and the fourth port 86 is connected to the drain port 88 so that the hydraulic pressure is discharged from the engagement side oil chamber 66. Therefore, since the hydraulic pressure is supplied to the release side oil chamber 64 and the hydraulic pressure is discharged from the engagement side oil chamber 66, the lockup clutch 26 is released from the inner surface of the front cover 62 and is released.
[0034]
On the other hand, when the solenoid valve 75 is ON-controlled, hydraulic pressure is applied to the lockup relay valve 74 in a direction opposite to the spring 78 and the spool moves, so that the first port 80 is changed to the fourth port 86. The second port 82 is connected in communication with the third port 84 while being connected in communication. Therefore, the regulator pressure Pcl is supplied to the engagement side oil chamber 66 and the hydraulic pressure adjusted by the lockup control valve 72 is supplied to the release side oil chamber 64.
[0035]
Accordingly, when the pressure regulation level of the lockup control valve 72 is lowered and the hydraulic pressure in the release side oil chamber 64 is lowered, the lockup clutch 26 is pressed against the inner surface of the front cover 62 to be engaged. Conversely, when the pressure regulation level of the lockup control valve 72 is increased, the hydraulic pressure (release pressure) of the release side oil chamber 64 is increased, so that the load with which the lockup clutch 26 is pressed against the inner surface of the front cover 62 is reduced. As a result, the lockup clutch 26 is slip-controlled, and when the release pressure is further increased, the lockup clutch 26 is gradually released.
[0036]
As will be understood from the above description, the lockup relay valve 74 and the solenoid valve 75 cause the differential pressure between the hydraulic pressure of the engagement side oil chamber 66 and the hydraulic pressure of the release side oil chamber 64 in the engagement direction of the lockup clutch 26. It functions as a mode switching means having an engagement mode for setting and a release mode for setting the differential pressure in the release direction of the lockup clutch 26. Further, the linear solenoid valve 70 and the lockup control valve 72 function as a differential pressure adjusting means for controlling the magnitude of the differential pressure between the hydraulic pressure in the engagement side oil chamber 66 and the hydraulic pressure in the release side oil chamber 64.
[0037]
The electronic control unit 54 indicates a signal indicating the engine rotational speed Ne detected by the rotational speed sensor 90, a signal indicating the throttle opening θ detected by the throttle opening sensor 92, and the vehicle speed V detected by the vehicle speed sensor 94. A signal and an ON / OFF signal from an idle switch (SW) 96 are input via the engine control device 100.
[0038]
The electronic control unit 54 also includes a signal indicating the rotational speed Nin of the input shaft 36 of the belt type continuously variable transmission mechanism 18 detected by the rotational speed sensor 102 and a signal indicating the shift range detected by the shift position (SP) sensor 104. An ON-OFF signal indicating whether or not a brake pedal (not shown) is depressed is input from the brake switch (SW) 108.
[0039]
The electronic control unit 54 controls the input-side rotational speed Nin of the belt-type continuously variable transmission mechanism 18 to a target input-side rotational speed Nint determined by the traveling state of the vehicle according to a shift control routine not shown in the drawing. The electronic control unit 54 controls the engagement state of the lock-up clutch 26 by controlling the linear solenoid valve 70 and the like according to the lock-up clutch control routine shown in FIGS. The engagement state of the forward clutch 38 and the reverse brake 40 is controlled according to the forward / reverse switching control routine.
[0040]
Particularly in the illustrated embodiment, the electronic control unit 54 engages the lock-up clutch 26 when the throttle opening θ and the vehicle speed V are in the engagement region (lock-up region) shown in FIG. When the opening θ and the vehicle speed V are in the non-engagement region (release region) shown in FIG. 5, the lockup clutch 26 is released, and the throttle opening θ and the vehicle speed V are in the non-engagement region shown in FIG. Even when the vehicle is in a specific driving state (for example, the idle switch 96 and the brake switch 108 are OFF, in other words, the driver is not braking and the driver is willing to accelerate) ), The lockup clutch 26 is engaged.
[0041]
Although a specific operating state region (extended engagement region) is shown in FIG. 5 for convenience, the specific operating state region is not a range determined by the throttle opening θ and the vehicle speed V. Note that it is in the non-engagement region but not in the fixed range.
[0042]
Further, when the throttle opening θ and the vehicle speed V change from the engagement region shown in FIG. 5 to the non-engagement region, the electronic control unit 54 applies the engagement pressure of the lockup clutch 26, that is, the engagement side oil chamber 66. The lockup clutch 26 is quickly released by rapidly reducing the differential pressure between the hydraulic pressure and the hydraulic pressure in the release-side oil chamber 64 with a normal decreasing gradient. The throttle opening θ and the vehicle speed V are shown in FIG. When the vehicle driving state changes from a specific driving state to a state other than the specific driving state in a situation where the vehicle is in the non-engagement region, the engagement pressure of the lockup clutch 26 is smaller than the normal decrease gradient. Decrease gently with a decreasing slope.
[0043]
Further, when the throttle opening θ and the vehicle speed V are in the non-engagement region shown in FIG. 5, the electronic control unit 54 changes the vehicle driving state to a specific driving state from a state other than the specific driving state. As in the case where the throttle opening θ and the vehicle speed V change from the non-engagement region shown in FIG. 5 to the engagement region, the engagement pressure of the lock-up clutch 26 is quickly increased to quickly activate the lock-up clutch. Engage.
[0044]
Although not shown in detail in the figure, the electronic control unit 54 and the engine control unit 100 have a CPU, a ROM, a RAM, and an input / output port unit, which are connected to each other by a bidirectional common bus. And a general configuration including a driving circuit.
[0045]
Next, the control of the lockup clutch in the illustrated embodiment will be described with reference to the flowcharts shown in FIGS. The control according to the flowcharts shown in FIGS. 3 and 4 is started by closing an ignition switch (not shown), and is repeatedly executed at predetermined time intervals.
[0046]
3 and 4, the flag Fa indicates whether the throttle opening .theta. And the vehicle speed V of the engine 12 are in the non-engagement region shown in FIG. 5, and whether the vehicle is in a specific driving state. 1 indicates that the driving state of the vehicle is in a specific driving state in the non-engagement region. The flag Fb relates to whether or not the lockup clutch 26 is being engaged and controlled at the time of start or reacceleration of the vehicle, and whether or not the lockup clutch has a torque transmission capacity. Alternatively, a state is shown in which the lock-up clutch 26 is under engagement control during re-acceleration and the lock-up clutch has a torque transmission capacity.
[0047]
First, in step 10, a signal indicating the rotational speed Ne of the engine 12 input from the engine control device 100 is read. In step 20, the throttle opening degree θ and the vehicle speed V of the engine 12 are shown in FIG. It is determined whether or not the vehicle is in the engagement region (lock-up ON region) shown in FIG. 4. If a negative determination is made, the process proceeds to step 50. If an affirmative determination is made, the process proceeds to step 30.
[0048]
In step 30, flags Fa and Fb are reset to 0. In step 40, solenoid valve 75 is turned on, and the pressure regulation level of lock-up control valve 72 is lowered to release the valve. The oil pressure in the oil chamber 64 is reduced, and thereby the engagement pressure of the lockup clutch 26 is increased, so that the lockup clutch is brought into the engaged state or maintained in the engaged state.
[0049]
In step 50, it is determined whether or not the driving state of the vehicle is in a specific driving state, that is, whether or not the vehicle is in a state of starting or reaccelerating and the lockup clutch 26 should be engaged. If a determination is made and an affirmative determination is made, the process proceeds to step 130. If a negative determination is made, the flag Fa is reset to 0 in step 60, and then the process proceeds to step 70.
[0050]
In step 70, it is determined whether or not the previous throttle opening θ and the vehicle speed V are in the engagement region shown in FIG. 5, that is, whether or not the lockup clutch 26 is to be released. When a positive determination is made, the hydraulic pressure in the release side oil chamber 64 is increased by increasing the pressure regulation level of the lockup control valve 72 in a state where the solenoid valve 75 is kept ON in step 80. As a result, the engagement pressure of the lockup clutch 26 starts to decrease. When a negative determination is made, the routine proceeds to step 90.
[0051]
In step 90, it is determined whether or not the engagement control at the time of starting or reacceleration of the vehicle is being performed, that is, whether or not the lockup clutch 26 is to be released. If YES is determined, the process proceeds to step 150. If YES is determined, the process proceeds to step 100.
[0052]
In step 100, it is determined whether or not the lockup clutch 26 has a torque transmission capacity. If a negative determination is made, the same procedure as in step 80 is performed in step 110. When a decrease in the engagement pressure is started and an affirmative determination is made, the flag Fb is set to 1 in step 120, and the engagement pressure of the lockup clutch 26 is set in the same manner as in step 80. The decline begins.
[0053]
In step 130, it is determined whether or not the flag Fa is already 1, that is, whether or not the lock-up clutch 26 is engaged because the vehicle is in a specific driving state. If the determination is affirmative, the process proceeds to step 150 as it is. If the determination is negative, the flag Fa is set to 1 in step 140 and the lock is performed in the same manner as in step 40. Increase in the engagement pressure of the up clutch 26 is started, and then the routine proceeds to step 150.
[0054]
In step 150, it is determined whether or not the engagement pressure reduction control of the lockup clutch 26 is being controlled. If a negative determination is made, control according to the flowcharts shown in FIGS. 3 and 4 is temporarily performed. When the determination is affirmative and the determination is affirmative, the routine proceeds to step 160.
[0055]
In step 160, it is determined whether or not the flag Fb is 1, that is, during engagement control of the lockup clutch 26 at the time of start or reacceleration of the vehicle, and the lockup clutch 26 has a torque transmission capacity. It is determined whether or not the engagement pressure is decreasing under the circumstances, and if a negative determination is made, in step 170, the decrease gradient of the engagement pressure of the lockup clutch 26 is the decrease gradient A in the normal state. When the determination is affirmative, the lowering gradient of the engagement pressure of the lockup clutch 26 is set to a lowering gradient B smaller than the gradient A in step 180, and then shown in FIG. 3 and FIG. The control according to the flowchart is temporarily terminated.
[0056]
In step 190, it is determined whether or not the control instruction value of the engagement pressure of the lockup clutch 26 is 0, that is, the decrease of the engagement pressure of the lockup clutch is completed and the release of the lockup clutch 26 is completed. When a negative determination is made, the control according to the flowcharts shown in FIGS. 3 and 4 is temporarily terminated, and when an affirmative determination is made, the solenoid valve 75 is The control is switched from ON to OFF, thereby ending the control for lowering the engagement pressure of the lockup clutch 26.
[0057]
As understood from the above description, when the throttle opening θ and the vehicle speed V are changed from the non-engagement region shown in FIG. 5 to the engagement region or in the engagement region, an affirmative determination is made at step 20. In step 40, the lock-up clutch 26 is engaged or maintained in the engaged state. On the other hand, when the throttle opening θ and the vehicle speed V are in the non-engagement region shown in FIG. 5, a negative determination is made in steps 20, 50, 70, 90, 150, whereby the lockup clutch 26 Is maintained in a released state.
[0058]
When the throttle opening θ and the vehicle speed V change from the engagement region shown in FIG. 5 to the non-engagement region, a negative determination is made in steps 20 and 50, but an affirmative determination is made in step 70. As a result, the engagement pressure of the lock-up clutch 26 starts to be decreased in step 80, a positive determination is made in step 150, and a negative determination is made in step 160. Until the affirmative determination is made, the engagement pressure of the lockup clutch 26 is reduced at the decreasing gradient A set in step 170, and therefore the lockup clutch 26 is released quickly.
[0059]
Even when the throttle opening θ and the vehicle speed V are in the non-engagement region shown in FIG. 5, when the vehicle is in a specific driving state, that is, the idle switch 96 and the brake switch 108 are turned off. When the vehicle starts or re-accelerates, a negative determination is made in step 20, but an affirmative determination is made in step 50, so that the engagement pressure of the lockup clutch 26 increases in step 140. As a result, the lockup clutch 26 is engaged.
[0060]
Further, in a situation where the throttle opening θ and the vehicle speed V are in the non-engagement region shown in FIG. 5, when the vehicle driving state becomes a state other than the specific driving state, that is, the idle switch 96 or the brake switch 108 is turned on. When the vehicle enters a state other than the state of starting or reacceleration, a negative determination is made in steps 50 and 70, and an affirmative determination is made in step 90.
[0061]
When the lockup clutch 26 has a torque transmission capacity, an affirmative determination is made in step 100, the flag Fb is set to 1 in step 120, and the engagement pressure of the lockup clutch 26 starts to decrease. In steps 150 and 160, an affirmative determination is made. In step 180, the decrease gradient of the engagement pressure of the lockup clutch 26 is set to a decrease gradient B smaller than the gradient A, and the subsequent steps are performed. By making a negative determination at 20, 50, 70, 90, the engagement pressure of the lock-up clutch 26 is gently lowered as compared with the normal release, and the lock-up clutch 26 is gently released.
[0062]
Therefore, when the throttle opening θ and the vehicle speed V change from the engagement region shown in FIG. 5 to the non-engagement region, that is, the vehicle operation region determined by the throttle opening θ and the vehicle speed V causes the lock-up clutch 26 to operate. When the predetermined operation region to be engaged changes to a region other than the predetermined operation region in which the lockup clutch 26 is to be released, the lockup clutch 26 can be quickly released to immediately respond to the change in the vehicle operation region. it can.
[0063]
On the other hand, when the throttle opening θ and the vehicle speed V are in the non-engagement region shown in FIG. 5, the driving state of the vehicle becomes a state other than the specific driving state, and at that stage, the lockup clutch When the torque transmission capacity of the lockup clutch 26 is present, the lockup clutch 26 can be gently released by gently lowering the engagement pressure of the lockup clutch 26 as compared with the normal release of the engagement. The shock when the lockup clutch 26 is released can be effectively reduced in a situation where the torque transmission capacity is present.
[0064]
  In the above situation, the engagement pressure of the lock-up clutch 26 is gently reduced as compared with the normal release of the engagement.The calm ofDuring the decline, the vehicle's driving condition isStateOr if the driving area of the vehicle isIn the areaIn this case, the time required to engage the lockup clutch by increasing the engagement pressure of the lockup clutch 26 can be shortened, whereby the lockup clutch can be quickly engaged.
[0065]
In general, in a continuously variable automatic transmission or automatic transmission incorporating a torque converter having a lock-up clutch, a torque converter having a high capacity coefficient is often used for the purpose of improving fuel consumption. However, when the capacity coefficient of the torque converter is increased, the capacity coefficient in a region where the speed ratio of the speed change mechanism is low is also increased, which causes a problem that fuel consumption increases during idling of the engine.
[0066]
According to the illustrated embodiment, the vehicle starts or reaccelerates in a vehicle speed range lower than the engagement range of the lock-up clutch 26 determined by the throttle opening θ and the vehicle speed V and the throttle opening θ is within a predetermined range. In this state, the lockup clutch 26 is immediately engaged, and power is transmitted by the lockup clutch 26 having a high capacity coefficient. Therefore, it is not necessary to increase the capacity coefficient of the torque converter, and the torque converter has a capacity coefficient. Therefore, the fuel consumption can be improved by avoiding an increase in fuel consumption during idling of the engine without deteriorating the fuel consumption when the vehicle is running.
[0067]
In particular, according to the illustrated embodiment, when the throttle opening θ and the vehicle speed V are in the non-engagement region shown in FIG. When the clutch 26 is released, the steps 190 and 200 are not executed as described above, and the solenoid valve 75 is not turned OFF even when the lockup clutch 26 is released, so the solenoid valve 75 is turned OFF. It is possible to reliably prevent the sudden change of the engagement pressure at the time of switching and the occurrence of the release shock due to this.
[0068]
Further, in a situation where the lock-up clutch 26 is released due to the vehicle operating state other than the specific driving state, when the throttle opening θ and the vehicle speed V are in the engagement region shown in FIG. By controlling the linear solenoid valve 70 while maintaining the valve 75 in the ON state, the pressure regulation level of the lockup control valve 72 is lowered, thereby reducing the release pressure and increasing the engagement pressure of the lockup clutch 26. Therefore, the lock-up clutch can be quickly engaged with certainty in response to such a change in the situation.
[0069]
Further, according to the illustrated embodiment, even if the vehicle driving state becomes a state other than the specific driving state in the situation where the throttle opening θ and the vehicle speed V are in the non-engagement region shown in FIG. When the torque transmission capacity of the lockup clutch 26 is not already present in the stage, that is, when there is no risk of a release shock of the lockup clutch 26, the gradient of decrease in the engagement pressure of the lockup clutch 26 is increased in step 170. Since the normal gradient A is set, the engagement pressure of the lockup clutch 26 can be quickly reduced and the lockup clutch 26 can be released quickly.
[0070]
Although the present invention has been described in detail with respect to specific embodiments, the present invention is not limited to the above-described embodiments, and various other embodiments are possible within the scope of the present invention. It will be apparent to those skilled in the art.
[0071]
For example, in the above-described embodiment, the idle switch 96 or the brake switch 108 is turned on when the throttle opening θ and the vehicle speed V are in the non-engagement region shown in FIG. When the engine is in a state other than the specific operation state from the specific operation state, the lockup clutch 26 is released more gently than usual, but the throttle opening θ and the vehicle speed V are as shown in FIG. The idle switch 96 or the brake switch is in a state where it is in the indicated non-engagement region, the engine speed is not less than the reference value, the traveling road is not an uphill road, and the temperature of the clutch oil is not in a low temperature state below the reference value. It may be modified so that the lock-up clutch 26 is released more gently than usual when 108 is turned on.
[0072]
In the above-described embodiment, the hydraulic control circuit 68 that controls the engagement pressure of the lockup clutch 26 adjusts the differential pressure between the hydraulic pressure of the engagement side oil chamber 66 and the hydraulic pressure of the release side oil chamber 64. A lockup relay valve 74 and a solenoid valve 75 functioning as mode switching means having an engagement mode for setting the engagement direction of the lockup clutch 26 and a release mode for setting the differential pressure in the release direction of the lockup clutch 26. And a linear solenoid valve 70 and a lock-up control valve 72 that function as differential pressure adjusting means for controlling the magnitude of the differential pressure between the hydraulic pressure in the engagement side oil chamber 66 and the hydraulic pressure in the release side oil chamber 64. However, as long as the hydraulic control circuit 68 that controls the engagement pressure of the lockup clutch 26 includes means that functions as mode switching means and differential pressure adjustment means, It may be of the configuration of the meaning.
[0073]
In the above-described embodiment, the speed change mechanism is the belt-type continuously variable transmission mechanism 18, but the speed change mechanism is, for example, any arbitrary variable speed known in the art such as a toroidal cone type continuously variable transmission mechanism. It may be a step transmission mechanism or an automatic transmission.
[Brief description of the drawings]
FIG. 1 is a skeleton diagram showing a vehicle power transmission device to which an embodiment of a lockup clutch control device according to the present invention is applied;
FIG. 2 is an explanatory diagram showing a hydraulic circuit that controls the engagement force of a lockup clutch incorporated in the torque converter of the power transmission device shown in FIG. 1;
FIG. 3 is a flowchart showing the first half of a lockup clutch control routine in the illustrated embodiment.
FIG. 4 is a flowchart showing a second half of a lockup clutch control routine in the illustrated embodiment.
FIG. 5 is a graph showing a lockup clutch control mode as a relationship between a vehicle speed V and a throttle opening θ.
[Explanation of symbols]
12 ... Engine
14 ... Torque converter
16 ... Forward / reverse switching device
18 ... Belt type continuously variable transmission mechanism
26 ... Lock-up clutch
39, 52, 68 ... Hydraulic control circuit
54 ... Electronic control unit
90 ... Rotational speed sensor
92 ... Throttle opening sensor
94: Vehicle speed sensor
96 ... Idle switch
100. Engine control device
102 ... Rotational speed sensor
104 ... Shift position sensor
108 ... Brake switch

Claims (3)

A vehicle lock-up clutch control device that engages a lock-up clutch in a predetermined operation region and releases the lock-up clutch in a region other than the predetermined operation region. the lock-up clutch to engage, prior Symbol predetermined operating vehicle operating conditions at the region other than the region of the specific vehicle operating condition when it is a specific vehicle operating condition is vehicle operating conditions at the region other than the when it is more a state other than the specific vehicle operating condition, the lock-up clutch to determine whether there is a torque transmission capacity, when the there is a lock-up clutch torque transmission capacity, operating range of the predetermined gently said lockup than release in the lock-up clutch when than the operating region becomes a region other than the predetermined operating region Vehicle lock-up clutch control apparatus characterized by releasing the Pukuratchi. When the time vehicle operating state during the mild release control becomes the specific vehicle operating condition or vehicle operating region of the lock-up clutch becomes the predetermined operating region, engages the lock-up clutch match vehicle lock-up clutch control device according to claim 1, characterized in Rukoto. The lockup clutch is configured to be engaged and disengaged by controlling a differential pressure between the engagement side pressure chamber and the release side pressure chamber, and the vehicle lockup clutch control device includes the differential pressure Mode switching means having an engagement mode for setting the engagement direction of the lockup clutch and a release mode for setting the differential pressure in the release direction of the lockup clutch, and a difference for adjusting the magnitude of the differential pressure Pressure adjusting means, and when the vehicle driving state is in a state other than the specific vehicle driving state in a region other than the predetermined driving region, the mode switching unit is set to the engagement mode, and The lockup clutch is released by reducing the magnitude of the differential pressure by the differential pressure adjusting means, and the mode switching unit is operated even when the lockup clutch is released. Vehicle lock-up clutch control device according to claim 1 or 2, characterized in that to maintain the engagement mode.

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