JP2924624B2 - Automatic transmission torque converter clutch control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a torque converter clutch control device for an automatic transmission used in an automobile.
More specifically, the present invention relates to a technique for improving fuel efficiency while preventing the occurrence of shock and judder.

[0002]

2. Description of the Related Art In an automatic transmission for an automobile, a transmission mechanism using a planetary gear is generally used. Are connected or fixed to obtain a desired gear. A torque converter, which is a fluid coupling, is interposed between the engine and the speed change mechanism to increase the engine torque at the time of starting or the like and transmit the torque to the speed change mechanism. To absorb shock.

[0003] Incidentally, the automatic transmission operates with the slippage of the torque converter, and therefore has the disadvantage that fuel efficiency is lower than that of a manual transmission. In order to solve this drawback, in recent automatic transmissions, a lock-up clutch (hereinafter referred to as a damper clutch) is provided in a torque converter.
In many cases, the input shaft (that is, the output shaft on the engine side) and the output shaft (that is, the input shaft on the transmission mechanism side) are directly connected in a predetermined operating range. As the operating area of the damper clutch, the input shaft and the output shaft are rigidly connected during power-on traveling at relatively high speed to prevent the slip loss, and in addition to the complete direct connection area, the power shaft is coupled with slight slip during power-off traveling. Directly connected to the deceleration area where fuel injection is stopped while preventing engine stall, and coupled with a slip of about several tens of revolutions during power-on traveling at a relatively low speed, making it difficult for engine torque fluctuations to be transmitted to the transmission. There is a slip connection area.

In the complete direct connection area, a sufficient and sufficient apply pressure (high oil pressure) is operated so that the damper clutch does not slip. On the other hand, in the deceleration direct connection area and the slip direct connection area, a damper clutch control valve (hereinafter, referred to as "slip") is used. Apply pressure (low hydraulic pressure) appropriately adjusted to achieve the target slip amount via control valve)
Act on the damper clutch. Generally, a spool valve is used as the control valve, and the control valve is operated by control hydraulic pressure duty-controlled by an electromagnetic valve.

When the vehicle shifts from the complete direct connection area or the slip direct connection area to the deceleration direct connection area, the running state is switched from power-on to power-off as described above. Therefore, at the moment of the transition, torque fluctuations of the engine occur, and when the damper clutch is kept in the directly connected state, the torque fluctuations are transmitted to the transmission side, and shocks and judders occur. Therefore, the drive of the solenoid valve is stopped for a predetermined time when shifting to the deceleration direct connection area, and the control valve is operated to the release side. As a result, the apply pressure is discharged and the release pressure is supplied, so that the damper clutch is in a non-direct connection state, a shock and a judder are avoided, and after that, a predetermined apply pressure is supplied to perform the deceleration direct connection control. .

[0006]

By the way, when shifting from the slip direct connection area to the deceleration direct connection area, the applied pressure in the torque converter is low. become. However, when shifting from the complete direct connection state to the deceleration direct connection area, the applied pressure is high, so even if the operation of the solenoid valve is stopped, it does not easily become the non-direct connection state, and the occurrence of the above-described shock and judder occurs. Could not be prevented. On the other hand, if the drive stop time of the solenoid valve is set to be long in order to solve this problem, the non-direct connection time becomes long when the application pressure is low, for example, when shifting from the slip direct connection area. For this reason, the engine speed is reduced, fuel injection is restarted, and the fuel consumption reduction effect is reduced.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a torque converter clutch control device for an automatic transmission that optimizes the reduction time of supply hydraulic pressure when shifting to a deceleration direct connection area. .

[0008]

In order to achieve this object, a torque converter clutch control device for an automatic transmission according to the present invention includes a vehicle automatic transmission and a torque converter connected to an engine. A clutch attached to the torque converter so that an input side and an output side of the torque converter can be rigidly connected to each other; and control means for controlling the torque converter and the clutch. The clutch is controlled such that a fully-coupled region that controls the clutch to a rigidly connected state, a non-directly-coupled region that controls the clutch not to be directly coupled, and a desired slip amount between the input side and the output side of the torque converter. A clutch divided into a slip direct connection area and a deceleration direct connection area for controlling the clutch to a desired slip state during deceleration operation of the vehicle. Hydraulic control means for controlling the hydraulic pressure supplied to the clutch so as to be in an operating state according to the hutch control map, and a torque fluctuation at the time of deceleration of the engine when the operating area of the clutch shifts to a deceleration direct connection area. Hydraulic pressure reducing means for reducing the hydraulic pressure supplied to the clutch for a predetermined time so as to absorb the pressure, and reducing time adjusting means for increasing or decreasing the predetermined time in accordance with the operating state of the clutch immediately before shifting to a deceleration direct connection area. It is characterized by having.

[0009]

According to the present invention, when shifting to the deceleration direct connection area,
For example, when a high apply pressure is supplied to the clutch and the slip amount is small, the hydraulic pressure supplied to the clutch is reduced over a relatively long period of time, so that the complete direct connection state can be reliably avoided. Further, when a low apply pressure is supplied to the clutch or the slip amount is large, the supply hydraulic pressure is reduced in a relatively short time to optimize the time for the non-direct connection state.

[0010]

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 schematic configuration diagram showing one embodiment of a torque converter clutch control device according to the present invention. In FIG. 1, an automatic transmission 2 is provided at a rear end of an engine 1.
And the output is transmitted to drive wheels (not shown) via the automatic transmission 2. The automatic transmission 2 includes a torque converter 3, a transmission main body 4, and a hydraulic controller 5, and is driven and controlled by an automatic transmission control ECU (electronic control unit) 6 installed in a vehicle interior or the like.
The transmission body 4 incorporates hydraulic friction engagement elements such as a hydraulic clutch and a hydraulic brake in addition to a plurality of sets of planetary gears. The hydraulic controller 5 contains a plurality of solenoid valves duty-driven by the ECU 6 in addition to a hydraulic circuit formed integrally.

On the other hand, the ECU 6 includes an input / output device (not shown) and a storage device (RO) containing a large number of control programs.
M, RAM, BURAM, etc.), central processing unit (CP
U), a timer counter, etc., at its input side, an electromagnetic pickup type NE sensor 8 for detecting an engine speed NE via a ring gear 7 of a flywheel, and a turbine speed NT for a torque converter 3. Sensor 9, an NO sensor 10 for detecting the rotational speed NO of a transfer drive gear (not shown), a throttle sensor 11 for detecting the opening degree .theta.TH of a throttle valve (not shown), and an operation discharged from an oil pump (not shown) in the torque converter 3. Oil temperature sensor 12 for detecting oil temperature of oil
Is connected. In addition to these sensors, the ECU 6 is connected to various sensors and switches, such as an inhibitor switch for detecting the position of the shift speed, and an idle switch for detecting the closed state of the throttle valve.

The torque converter 3 includes a housing 20,
The pump 22 includes a casing 21, a pump 22, a stator 23, a turbine 24, and the like.
1 is connected to a drive shaft 25 as an input shaft. Further, the stator 23 is connected to the housing 20 via a one-way clutch 26, and the turbine 24 is connected to an input shaft 27 of the transmission body 4 as an output shaft. Further, a casing 21 is provided in the torque converter 3.
Single-plate type damper clutch 2 between the turbine and the turbine 24
The drive shaft 25 and the input shaft 27 can be directly connected by the engagement of the damper clutch 28. The damper clutch 28 is driven by hydraulic oil supplied from a damper clutch hydraulic control circuit 40 via oil passages 29 and 30.

A control valve 41, which is the center of the damper clutch oil pressure control circuit 40, is driven by a normally closed solenoid valve 42 to control the oil pressure supplied to the damper clutch 28, and is located at both ends of the spool 43. A left end chamber 44 and a right end chamber 45, oil passages 46 and 47 for introducing pilot pressure to both chambers 44 and 45, a spring 48 for urging the spool valve 43 rightward in the drawing, and the like.
The oil passage 46 to the left end chamber 44 is connected to the solenoid valve 42 via a branch oil passage 49. When the solenoid valve 42 is in the closed state (ie, OFF position), the left end chamber 44 and the right end chamber 45 are connected.
, The spool valve 43 biased by the spring 48 moves rightward. When the solenoid valve 42 is in the released state (ie, the ON position), the pilot pressure on the left end chamber 44 side is released, and the spool valve 43 is moved leftward by being urged by the pilot pressure on the right end chamber 45 side. The orifices 46a and 49a are formed in the oil passage 46 and the branch oil passage 49, respectively, to prevent a sudden change in pilot pressure.

When the spool valve 43 moves rightward, a torque converter lubricating oil pressure (release pressure) is applied between the casing 21 and the damper clutch 28 via the oil passage 29.
Is supplied, and at the same time, the working oil is discharged from the casing 21 through the oil passage 30. Then, the damper clutch 28 is released (non-direct connection state), and the rotation of the drive shaft 25 is transmitted to the input shaft 27 via the pump 22 and the turbine 24. On the other hand, when the spool valve 43 moves to the left, the casing 21
Hydraulic oil is discharged between the hydraulic fluid and the damper clutch 28, and at the same time, the apply pressure based on the pressure regulation of the control valve 41 is supplied into the casing 21 through the oil passage 30. Then, the damper clutch 28 is brought into the connected state (completely directly connected state), and the rotation of the drive shaft 25 is directly transmitted to the input shaft 2.
7 is transmitted.

The connection / disconnection of the damper clutch 28 and the supply hydraulic pressure are determined by the position of the spool valve 43, that is, the pressure difference between the pilot pressure supplied to the left end chamber 44 and the right end chamber 45. It is controlled by duty driving. For example, the ECU 6 sets the solenoid valve 42 to 8
When driven at a duty ratio of about 0%, the pilot pressure in the left end chamber 44 is discharged through the branch oil passage 49 and the solenoid valve 49, the spool valve 43 moves to the left end, and the damper clutch is actuated by the action of the above-described apply pressure. 28 is completely connected. When the solenoid valve 42 is driven at a duty ratio of 0% (that is, when it is not driven at all), the pilot pressure in the left end chamber 44 and the pilot pressure in the right end chamber 45 are balanced, so that the spool 48 is urged by the spring 48 to move the spool 43 to the right end. The damper clutch 28 is brought into a non-direct connection state by the action of the release pressure described above. Then, a predetermined duty ratio (for example, 2
(5% to 35%), a low apply pressure state can be created, and the damper clutch 28 is in a deceleration direct connection state or a slip directly connected state.

Hereinafter, the control procedure in this embodiment will be described with reference to control flowcharts, graphs, and the like in FIGS. The driver turns on the ignition key,
When the engine 1 starts, the main routine shown in the flowchart of FIG. 2 is repeatedly executed at a predetermined control interval (for example, 65.5 ms).

When the main routine is started, first, in step S1, the ECU 6 sets each initial value. Next, the ECU 6 determines in step S2 various sensors, that is,
The detection signals from the NE sensor 8, the NT sensor 9, the NO sensor 10, the throttle sensor 11, the oil temperature sensor 12, and the like are read and stored in the RAM. Next, in step S3, the ECU 6 determines a gear position to be established by the transmission main body 4 from the throttle opening θTH and the rotational speed NO of the transfer drive gear. Is determined. Then, if the determination in step S4 is negative (NO), that is, if the determination result of the gear position is the same, the process proceeds to step S2 and the process is repeated. Also, the determination in step S4 is affirmative (YES),
That is, when the result of the determination of the shift speed changes, a shift signal corresponding to the result of the determination in step S3 is output in step S5, and then the process proceeds to step S2 to repeat the processing.
Thereafter, the ECU 6 drives the transmission main body 4 by the hydraulic controller 5 in accordance with the shift signal output in step S5 to perform the shift control.

On the other hand, the ECU 6 operates on the basis of the map shown in FIG.
8 is performed. In this map, the horizontal axis is the turbine speed NT, and the vertical axis is the throttle opening θTH. As shown in the figure, the turbine speed NT is relatively high, and the throttle opening θ
If it is larger, most of the area is a complete direct connection area, and the damper clutch 28 is completely directly connected controlled. That is, as described above, the casing 2
1, while the apply pressure is supplied to the damper clutch 2
The release pressure is discharged from between the casing 8 and the casing 21,
The damper clutch 28 is engaged. Note that on the power online LPO, the engine speed NE and the turbine speed NT theoretically match, and neither acceleration nor deceleration is performed. However, actually, the engine may be slightly accelerated or decelerated due to a variation in engine output.

If the throttle opening θTH is smaller than the power online LPO, the turbine speed NT is slightly higher than the idle speed (in this embodiment, 1200).
rpm or more) are all directly connected to deceleration. In the deceleration direct connection area, the minimum applied pressure is supplied to the damper clutch 28 through learning, and the engine 1 and the transmission body 4 are directly connected via the damper clutch 28 with a predetermined slip amount, while sudden braking is performed. At times, the damper clutch 28 is quickly released, and engine stall can be avoided. still,
At the time of direct connection with deceleration, the fuel supply can be stopped while the rotation of the engine 1 is maintained, so that there is a great effect in improving fuel efficiency.

In this embodiment, when the operating state enters the deceleration direct connection area, the deceleration direct connection control routine shown in the flowcharts of FIGS. 4 to 7 is executed. When the deceleration direct connection control is started, in step S9, the ECU 6 first stores a predetermined time (65.5 ms in this embodiment) before the control start time (ss point in FIG. 9) stored in the RAM. , The drive duty ratio DUL of the electromagnetic valve 42 and the slip amount SDL of the damper clutch 28 are called. Next, in step S10, the ECU 6 searches the map of FIG. 8 for the solenoid valve drive stop time t1 based on the drive duty ratio DUL and the slip amount SDL. As shown in this map, the solenoid valve drive stop time t1 is equal to the control interval (65.5 m).
s), and is set longer as the drive duty ratio DUL is larger and the slip amount SDL is smaller, that is, as the apply pressure in the torque converter is higher. When the slip amount is greater than 250 rpm, the solenoid valve drive stop time t1 is set to 0 regardless of the drive duty ratio DUL.

When the setting of the solenoid valve drive stop time t1 is completed, in step S11, the ECU 6 sets the drive duty ratio of the solenoid valve 42 to 0% for t1 seconds, as shown in the graph of FIG. While applying the pressure, the apply pressure is discharged, and the damper clutch 28 is set in the non-direct connection state or the slip direct connection state (section A in FIG. 9). At this time, when the apply pressure in the torque converter is high, t1 is set to be long, so that the apply pressure is sufficiently discharged and the completely connected state can be reliably avoided. Therefore, the torque fluctuation of the engine 1 is not transmitted to the transmission 2 side, and the occurrence of shock and judder is prevented. On the other hand, when the apply pressure in the torque converter is low, t1 is short or set to 0.
The time of the non-direct connection state is not longer than necessary, and the fuel injection is not restarted due to the decrease in the engine speed, and the fuel consumption is reduced.

Next, at step S12, the ECU 6 determines whether or not the current operation state is in the deceleration direct connection area. If this determination is NO, the deceleration direct connection control is terminated at step S13, and a control flag F1 described later is set. , F2 are reset and the drive duty ratio is set in accordance with another control range to drive the solenoid valve 42. On the other hand, if the determination in step S12 is YES, the ECU 6 proceeds to step S14, and sets the solenoid valve 42 at a predetermined loose duty ratio DG1 for a predetermined time t2 seconds (65.5 ms in this embodiment). The damper clutch 28 is driven to supply the apply pressure and to reduce the play of the damper clutch 28 (section B in FIG. 9). Here, the rattling duty ratio DG1 is calculated from the throttle opening θTH and the turbine rotational speed NT immediately before entering the deceleration direct connection area, as shown in FIG.
B1 to B16 from the stuffing duty ratio map shown in FIG.
Is selected. It should be noted that the value in this map is set to be small in the transition from the completely connected region where the throttle opening θTH is large and the turbine speed NT is high because the applied pressure is high. The transition is set to be large because the residual pressure of the apply pressure is low.

After reducing the play of the damper clutch 28 in step S14, the ECU 6 proceeds to step S15.
Then, it is determined again whether or not the current operating state is in the deceleration direct connection area. If this determination is NO, the deceleration direct connection control is ended in step S16, and the same control as step S13 is executed. On the other hand, the determination in step S15 is YES
In this case, the ECU 6 starts the deceleration feedback control after step S17 (section C in FIG. 9). In step S17, the ECU 6 first sets a feedback start duty ratio DG2, and reads this as a feedback control duty ratio DG3. The feedback start duty ratio DG2 is calculated from BURA based on the throttle opening θTH and the turbine speed NT immediately before entering the deceleration direct connection area.
One of the values C1 to C16 is selected from the feedback start duty ratio map shown in FIG. The value in this map is also set to a small value in the transition from the complete direct connection region where the throttle opening θTH is large and the turbine speed NT is high, similarly to the backlash duty ratio DG1, because the residual pressure of the apply pressure is high. In the transition from the non-direct connection area or the like, the pressure is set large because the residual pressure of the apply pressure is low.

Next, the ECU 6 proceeds to step S1 in FIG.
At t3 seconds after the start of feedback at 8 (in this embodiment, 1
Second), and if NO, the process proceeds to step S19. In step S19, the ECU 6 determines whether or not t4 seconds (2.5 seconds in this embodiment) have elapsed since the start of the feedback.
Proceed to. Then, in step S20, the ECU 6 outputs the duty ratio DG3 and drives the solenoid valve 42 in duty. Note that, of course, immediately after the control, the determinations in step S18 and step S19 are NO.

Next, at step S21, the ECU 6 again determines whether or not the current operating state is in the deceleration direct connection area. If this determination is NO, the deceleration direct connection control is terminated at step S22, and step S13 is executed. The same control as described above is executed. On the other hand, if the determination in step S21 is YES,
The ECU 6 proceeds to step S23, and determines whether the deviation between the actual slip amount and the target slip amount is smaller than a threshold value -a (a is a positive value). Here, the slip amount is obtained by subtracting the turbine speed NT from the engine speed NE.
If the determination is YES, the ECU 6 corrects the duty ratio DG3 by adding a predetermined value d1 in step S24, increases the coupling oil pressure of the damper clutch 28, and reduces the slip amount.

The ECU 6 that has corrected the duty ratio DG3
Then, in step S25, it is determined whether or not the control flag F1 is 1, and if NO, the process proceeds to step S18, and the duty ratio DG3 is output in step S20. If the determination in step S25 is YES, the process proceeds to step S26 to determine whether the control flag F2 is 1. And
If the determination in step S26 is NO, step S19
And the duty ratio DG3 is output in step S20, and if YES, the flow shifts to step S20 to output the duty ratio DG3.

On the other hand, if the determination in step S23 is NO, the ECU 6 proceeds to step S27 in FIG. 6, and the deviation between the actual slip amount and the target slip amount is larger than a threshold value b (b is a positive value). It is determined whether or not. If the determination is YES, the ECU 6 corrects the duty ratio DG3 by subtracting the predetermined value d2 from the duty ratio DG3 in step S28, reduces the coupling oil pressure of the damper clutch 28, and increases the slip amount.

The ECU 6 that has corrected the duty ratio DG3
Then, in step S29, it is determined whether or not the control flag F1 is 1, and in the case of NO, the process proceeds to step S18, and the duty ratio DG3 is output in step S20. If the determination in step S29 is YES, the process proceeds to step S30, where it is determined whether the control flag F2 is 1. And
If the determination in step S30 is NO, step S19
And the duty ratio DG3 is output in step S20, and if YES, the flow shifts to step S20 to output the duty ratio DG3.

On the other hand, if the determination in step S27 is NO, the ECU 6 determines that the actual slip amount is within an appropriate range, and in step S31 sets the duty ratio DG3 to the same value as the previous value, and sets the engagement hydraulic pressure of the damper clutch 28. Is not corrected. Also in this case, the ECU 6 determines whether or not the control flag F1 is 1 in step S32. If the determination is NO, the ECU 6 proceeds to step S18, and outputs the duty ratio DG3 in step S20. If the determination in step S32 is YES, the process proceeds to step S33 to determine whether the control flag F2 is 1. If the determination in step S33 is NO, the process proceeds to step S19, and the duty ratio DG3 is output in step S20. If the determination is YES, step S2 is performed.
Then, the duty ratio DG3 is output.

In this way, the actual slip amount of the damper clutch 28 gradually approaches the target slip, and a deceleration direct connection by a desired coupling oil pressure is realized. When t3 seconds have elapsed after the start of feedback, the determination in step S18 becomes YES, and the ECU 6 stores the current duty ratio D1 in the RAM in step S34,
After substituting 1 for the control flag F1 in step S35, the process proceeds to step S19. Also, after feedback starts, t
After 4 seconds, the determination in step S19 is also YES, and the ECU 6 stores the current duty ratio D2 in step S36, further substitutes 1 for the control flag F2 in step S37, and then proceeds to step S38 in FIG. Note that the graph of FIG. 12 shows the feedback start time (point S0).
, The duty gradually rises, and when t3 seconds elapse (S1
T4 seconds after the duty ratio D1 (point S2) (point S2)
In this case, the duty ratio D2 of FIG.

In step S38, the ECU 6 first calculates the duty ratio change amount ΔD (= D2 -D1) when shifting from the point S1 to the point S2, and determines whether the deceleration feedback start hydraulic pressure DG2 is excessive or insufficient. Next, the ECU 6
In step S39, a learning correction value β is searched from the map of FIG. 13 based on the duty ratio change amount ΔD. As shown in this map, even if the duty ratio change amount ΔD linearly increases or decreases, the learning correction value β is set to increase or decrease stepwise and slightly. For example, the duty ratio change amount ΔD is 0.4 to 1.2.
In the range of%, the learning correction value β is uniformly set to 0.4%.

Therefore, when the apply pressure in the feedback control becomes higher than the convergence hydraulic pressure of the feedback control, for example, by 5% or more, the direct connection state of the damper clutch 28 is reduced when sudden braking is performed on a low μ road at that time. There is a possibility that engine release will be delayed and the engine speed NE will drop to cause engine stall. However, since the correction amount β is set low, the apply pressure is also kept low, and the occurrence of engine stall and shock is prevented.

As can be seen from the setting of the duty ratio DG2 at the time point S0 shown in FIG. 12, the duty ratio DG2 of the feedback control start hydraulic pressure is set lower than the convergence hydraulic pressure. , The effect of suppressing the above-described apply pressure and preventing the occurrence of engine stall and shock is reliably obtained.

When the learning correction value β is obtained, the ECU 6
In step S40, the learning correction value β is added to the current feedback start duty ratio DG2 (DG2 = DG2 +
β) and stores it in the BURAM so that this becomes the next feedback start duty ratio DG2. That is, among the values (C1 to C16) in the feedback start duty ratio map in FIG. 11 described above, the value used this time is updated. Thus, each time the deceleration direct connection control is performed, the value of the feedback start duty ratio DG2 is gradually optimized, and a desired deceleration direct connection state can be obtained in a short time. As the learning control proceeds, the applied pressure at the start of the feedback converges to about 0.5 kg / cm ² .

Next, in step S41, the ECU 6 determines whether or not the duty ratio change amount ΔD is greater than a threshold value c (c> 0). If the determination is YES, the deceleration direct connection control is performed in step S42. The process is terminated, and the same control as in step S13 is performed. Further, in step S43, it is determined whether or not the duty ratio change amount ΔD is smaller than a threshold value -f (f> 0). If this determination is YES, the direct deceleration control is ended in step S44, and step S13 is performed.
The same control as described above is executed.

Accordingly, when the operating oil pressure in the feedback control becomes lower than required or becomes too high irrespective of the above-mentioned respective controls, the feedback control is interrupted and the occurrence of a shock to the drive system is prevented. At the same time, occurrence of engine stall is also prevented. That is, when the operating oil pressure in the feedback control becomes lower than the convergent oil pressure by 5% or more in the duty ratio, the control is started from the non-direct connection area, so that the engine speed NE decreases, and the fuel cut of the engine is stopped. May be In addition, the increase in the slip amount may increase the feedback hydraulic pressure and cause a shock.

The occurrence of such a shock takes 10 seconds or more after the start of the feedback control.
When it is determined that the change in the duty ratio ΔD is equal to or more than the predetermined value and a shock occurs if the control is continued as it is, the feedback control is interrupted in a sufficiently short time,
Shift to non-direct connection control. This prevents the occurrence of a shock.

Further, the problem caused by the feedback control in the deceleration direct connection area being performed at a low oil pressure of about 0.5 kg / cm ² is also solved. That is, in order to quickly release the direct connection of the damper clutch 28 when required,
Although a sufficient release pressure is required, in a state where the operating pressure of the entire control system is small and the release pressure of the damper clutch 28 is also small, the direct connection state is released. Even if the pressure is excessive, it takes time to release the excess.

This is because the release pressure supplied from the oil pump driven by the engine 1 cannot be rapidly increased because the fuel supply to the engine 1 itself is also cut by the deceleration direct connection control. It depends. Therefore, when the braking for rapidly reducing the rotation speed on the wheel side is performed and the direct connection is not sufficiently released, the braking force is transmitted to the engine 1 side, and the engine 1 may be stopped.

In this embodiment, when the operating state enters the slip direct connection area, the slip direct connection control routine shown in the flowchart of FIG. 14 is executed. When the slip direct connection control is started, in step S50, the ECU 6
First, a predetermined value Δd1 is obtained from the feedback start duty ratio DG2 learned in the deceleration direct connection control (in this embodiment,
3%), this is set as the feedback start duty ratio DG4 in the slip direct connection control, and the solenoid valve 42 is duty-driven in step S51. At the start of the slip direct coupling control, the power-on state is maintained when the vehicle shifts from the complete direct coupling region, and when the vehicle shifts from the deceleration direct coupling region, the damper clutch 28 is allowed to slip. The non-direct connection control and the backlash control of the damper clutch 28 as in the start of the control are not performed.

Here, the reason for obtaining the feedback start duty ratio DG4 of the slip direct connection control using the feedback start duty ratio DG2 obtained by the deceleration direct connection control is as follows. Since the feedback start duty ratio DG2 obtained in the deceleration direct connection control converges to a duty ratio equivalent to about 0.5 kg / cm ² , if this value is used, the feedback control start hydraulic pressure in the slip direct connection control is reduced to 0 kg.
/ Cm ² or more and a low oil pressure that does not cause a shock.

Therefore, a desired value can be easily obtained from the learning value in the deceleration direct connection control without performing independent learning correction in the slip direct connection control. Also,
When the slip is directly connected, the power is in the on state, so there is a lot of torque fluctuation. On the other hand, when the deceleration is directly connected, the power is in the off state, so the control stability is much higher and it is very suitable for learning correction. No.

Next, in step S52, the ECU 6 determines whether or not the current operation state is in the slip direct connection area. If the determination is NO, the ECU 6 ends the deceleration direct connection control in step S53, and terminates each control area. The solenoid valve 42 is driven in accordance with. On the other hand, if the determination in step S52 is YES,
The ECU 6 proceeds to step S54, and determines that the deviation between the actual slip amount and the target slip amount is equal to a threshold value e (10 rpm in this embodiment).
) To determine whether it is greater than. If the determination is YES, the ECU 6 corrects the duty ratio DG4 by adding a predetermined value d3 in step S55, increases the coupling oil pressure of the damper clutch 28, and reduces the slip amount. Thereafter, the process returns to step S51, and outputs the duty ratio DG4. Naturally, in the power-on slip direct connection area, contrary to the deceleration direct connection area,
The engine speed NE is always higher than the turbine speed NT.

If the determination in step S54 is NO, the ECU 6 proceeds to step S56, in which the deviation between the actual slip amount and the target slip amount is set to a threshold value h (in this embodiment, -h).
10 rpm). If the determination is YES, the duty ratio DG4 is corrected to reduce the predetermined value d4 in step S57, the coupling oil pressure of the damper clutch 28 is reduced, and the slip amount is increased. Thereafter, the flow returns to step S51, and the duty ratio DG4
Is output.

If the determination in step S56 is NO
In the case of, it is determined that the actual slip amount is in the appropriate range, and in step S58, the duty ratio DG4 is set to the same value as the previous value, and the flow returns to step S51 without correcting the hydraulic pressure supplied to the damper clutch 28, The duty ratio DG4 is output. Embodiments of the present invention are not limited to the above embodiment. For example, in the above-described embodiment, the operating state of the damper clutch is determined based on the drive duty ratio of the solenoid valve, that is, the hydraulic pressure supplied to the apply side and the slip amount, but is determined based on the engine load and the slip amount. You may do so. As the engine load at this time, a throttle opening, an intake air amount, an intake charging efficiency, an intake pipe pressure, a fuel supply amount, and the like may be used. Further, in the above-described embodiment, the solenoid valve is completely stopped when the vehicle enters the deceleration direct connection area.However, the solenoid valve may be driven at a predetermined duty ratio. A proportional solenoid valve or the like may be used, or the control valve may be driven by a motor or the like. Further, the specific procedure of the control can be appropriately changed without departing from the gist of the present invention.

[0046]

As described in detail above, according to the torque converter clutch control device of the present invention, a high apply pressure is supplied to the clutch and the slip amount is small when shifting to the deceleration direct connection area. In such a case, the hydraulic pressure supplied to the clutch is reduced for a relatively long time. Conversely, when a low apply pressure is supplied to the clutch or the slip amount is large, the reduction of the hydraulic pressure supplied is relatively short. Since the time is set, the non-direct connection state is reliably obtained, so that the shock and the judder do not occur, and the deterioration of the fuel efficiency due to the long non-direct connection state is prevented.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of a torque converter clutch control device according to the present invention.

FIG. 2 is a flowchart showing a shift control main routine.

FIG. 3 is a map showing a control range of a damper clutch.

FIG. 4 is a flowchart illustrating a procedure of deceleration direct connection control.

FIG. 5 is a flowchart illustrating a procedure of deceleration direct connection control.

FIG. 6 is a flowchart illustrating a procedure of deceleration direct connection control.

FIG. 7 is a flowchart illustrating a procedure of deceleration direct connection control.

FIG. 8 is a map for determining a solenoid valve drive stop time in deceleration direct connection control.

FIG. 9 is a graph showing a change in a solenoid valve driving duty in deceleration direct connection control.

FIG. 10 is a map of a loose duty ratio in deceleration direct connection control.

FIG. 11 is a map of a feedback start duty ratio in deceleration direct connection control.

FIG. 12 is a graph showing a change in a solenoid valve drive duty in deceleration direct connection control.

FIG. 13 is a map for searching for a learning correction value in deceleration direct connection control.

FIG. 14 is a flowchart showing a procedure of slip direct connection control.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine 2 Automatic transmission 3 Torque converter 4 Transmission body 5 Hydraulic controller 6 ECU 25 Drive shaft 27 Input shaft 28 Damper clutch 41 Damper clutch control valve 42 Solenoid valve

Continuation of the front page (56) References JP-A-7-42825 (JP, A) JP-A-1-206160 (JP, A) JP-A-7-198034 (JP, A) JP-A-3-37474 (JP) JP-A-4-203561 (JP, A) JP-A-4-64768 (JP, A) JP-A-4-39131 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB Name) F16H 61/14

Claims (3)

(57) [Claims] An automatic transmission for a vehicle, a torque converter connected to an engine, a clutch attached to the torque converter so that an input side and an output side of the torque converter can be rigidly connected; A converter and a control means for controlling the clutch, further comprising: a complete direct connection area for controlling the clutch to be in a rigid connection state; a non-direct connection area for controlling the clutch to be in a state of not being directly connected; The input side and the output side of the converter are divided into a slip direct connection area for controlling the clutch so as to have a desired slip amount, and a deceleration direct connection area for controlling the clutch to a desired slip state during deceleration operation of the vehicle. Hydraulic control means for controlling a hydraulic pressure supplied to the clutch so as to be in an operating state according to the clutch control map. When the operating area of the switch has shifted to the deceleration direct connection area,
Hydraulic pressure reducing means for reducing a hydraulic pressure supplied to the clutch for a predetermined time so as to absorb a torque fluctuation at the time of deceleration of the engine; and the predetermined pressure corresponding to an operating state of the clutch immediately before shifting to a deceleration direct connection area. A torque converter clutch control device for an automatic transmission, comprising a reduction time adjusting means for increasing or decreasing the time. 2. The method according to claim 1, wherein the reducing time adjusting means determines an operating state of the clutch from a hydraulic pressure supplied from the hydraulic pressure controlling means to the clutch and the slip amount immediately before shifting to a deceleration direct connection area. The torque converter clutch control device for an automatic transmission according to claim 1 . 3. The method according to claim 1, wherein the reducing time adjusting means determines an operating state of the clutch based on an engine load and the slip amount immediately before shifting to a deceleration direct connection area.
The torque converter clutch control device for an automatic transmission according to claim 1 .