JPH0771595A - Clutch control device of fluid coupling of automatic transmission for vehicle - Google Patents

Abstract

PURPOSE:To prevent clutch hydraulic pressure from becoming excessively high by feedback controlling decelerating time engagement hydraulic pressure as an initial value so that a difference between pump rotating speed and turbine rotating speed becomes a desired value and learning and correcting the initial value at the time when a car body speed change rate is within a specified range. CONSTITUTION:This device is furnished with a hydraulic circuit 40 to control a gear speed change device 30 under control of a transmission control unit TCU16 and a clutch hydraulic control circuit 50 to control a direct clutch 28 of a torque converter 20. By the TCU16, it is discriminated which of a clutch control range a current vehicle driving condition in accordance with output of a throttle valve opening sensor 18 corresponds to. During decelerating driving, only at the time when a car speed change rate is within a specified range in the case when supply hydraulic pressure to the direct clutch 28 is feedback controlled, by using a correction amount based on variation of a duty rate of a solenoid valve 54 for a clutch, a feedback starting duty rate is learned and corrected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a clutch control device for a fluid coupling of an automatic transmission for a vehicle.

[0002]

2. Description of the Related Art There is known an automatic transmission of a type in which a torque converter connected to an engine is provided with a clutch (hereinafter referred to as a damper clutch) for connecting and disconnecting an input side and an output side of the torque converter. . In a vehicle equipped with this type of automatic transmission, a predetermined operating condition, for example, when the operating condition that each of the throttle opening of the engine and the turbine speed of the torque converter is a predetermined value or more is satisfied, The damper clutch is directly connected to replace the fluid frictional engagement of the torque converter with the mechanical frictional engagement by the damper clutch, thereby improving the fuel consumption.

[0003]

On the other hand, during the deceleration operation of the vehicle, the damper clutch is generally set in the non-direct connection state. In this case, the rotational force acting on the engine from the drive wheels is transmitted through the torque converter in the fluid friction engagement state, and therefore the engine rotational speed reduction preventing action of this rotational force is poor. For this reason, when the fuel supply to the engine is cut due to the deceleration operation, the engine speed rapidly decreases, and the fuel supply must be restarted to prevent the engine stall. As a result, the fuel cut period may be shortened, and sufficient fuel efficiency may not be achieved.

Therefore, even during the deceleration operation, the damper clutch is directly connected, and the function of preventing the engine speed from lowering due to the rotational force acting on the engine from the drive wheels is effective, thereby extending the fuel cut period and improving the fuel consumption. Is being attempted. When such a damper clutch direct connection control is performed, it is necessary to appropriately control the magnitude of the hydraulic pressure supplied to the damper clutch in order to bring the damper clutch into the engaged state. Therefore, it is attempted to learn about the clutch hydraulic pressure that the clutch supply hydraulic pressure used in the next deceleration operation is adjusted based on the monitoring result of the hydraulic pressure supplied to the damper clutch during the deceleration operation.

On the other hand, if a sudden braking is performed on a low μ road while directly controlling the damper clutch, there is a problem that an engine stall may occur. The reason for this is that if the clutch oil pressure is excessively high, the release of the direct connection state of the damper clutch is delayed at the time of sudden braking, and the engine speed rapidly decreases as the axle speed rapidly decreases due to the sudden braking.

Therefore, an object of the present invention is to provide an automatic transmission for a vehicle in which a damper clutch is directly connected during deceleration operation of the vehicle and learning is performed to make the clutch hydraulic pressure appropriate. An object of the present invention is to provide a clutch control device for a fluid coupling of an automatic transmission for a vehicle, which can surely prevent an excessive increase, thereby preventing a delay in releasing the damper clutch directly connected state during sudden braking and an engine stall. To aim.

[0007]

A pump is provided between an engine and an auxiliary transmission of an automatic transmission and is connected to an output side of the engine, and a turbine is connected to an input side of the auxiliary transmission. In a fluid coupling of an automatic transmission for a vehicle, a clutch control device of the present invention has a clutch capable of connecting and disconnecting a pump and a turbine, and controls a hydraulic pressure supplied to the clutch according to a vehicle operating state. In the driving state detection means for detecting the vehicle driving state, and when the driving state detection means detects that the vehicle has entered the deceleration state, the deceleration engagement hydraulic pressure is supplied to the clutch. Feedback control is performed with the engaging hydraulic pressure during deceleration as the initial value so that the difference between the rotational speed of the pump and the rotational speed of the turbine detected by the operating means and the supply means is desired. A feedback control means that, only when the vehicle speed change rate of the vehicle is detected to be within a predetermined range by operating condition detecting means, characterized by having a learning correction means for learning correction of the initial value.

Preferably, the deceleration range regarded as the deceleration state is
The range is set so that the engine load is low and the turbine rotation speed is equal to or higher than a predetermined low rotation speed.
Preferably, the clutch control device discharges hydraulic pressure from the clutch when it is detected that a deceleration state is entered, and sets the pump and the turbine to a state immediately before engagement after the hydraulic pressure is discharged by the hydraulic pressure discharge means. As described above, the vehicle further includes a predetermined hydraulic pressure supply unit that supplies a predetermined hydraulic pressure to the clutch, and the deceleration engagement hydraulic pressure is supplied after the predetermined hydraulic pressure is output.

Preferably, the clutch control device represents a time measuring means for measuring an elapsed time from the start of the feedback control, and a hydraulic pressure value supplied to the clutch when a first predetermined time has elapsed from the start of the feedback control. A first oil pressure value detecting means for detecting a first oil pressure value, and a second oil pressure value supplied to the clutch when a second predetermined time set longer than the first predetermined time has elapsed from the start of the feedback control. A second hydraulic pressure value detecting means for detecting a hydraulic pressure value, and a hydraulic pressure difference calculating means for calculating a difference between the first hydraulic pressure value and the second hydraulic pressure value are further provided, and the learning correction means has a learning initializing means according to the hydraulic pressure difference. Correct the oil pressure.

Preferably, the clutch control device further comprises feedback control stopping means for stopping the feedback control and discharging the hydraulic pressure from the clutch when the hydraulic pressure difference is outside the predetermined range. Preferably, the operating state detection means,
At least one of a vehicle speed detecting means, a lateral acceleration detecting means, a wheel speed detecting means, a longitudinal acceleration detecting means, and a road surface gradient detecting means is provided, and the vehicle body speed change rate is obtained according to an output value from the at least one detecting means. .

Preferably, the clutch control device further includes an electromagnetic valve for duty-controlling the hydraulic pressure supplied to the clutch, and the hydraulic pressure supply to the clutch and the hydraulic pressure discharge from the clutch are performed at a duty ratio given to the electromagnetic valve.

[0012]

When the deceleration state of the vehicle is detected by the driving state detection means, preferably when the engine load is low and the turbine rotation speed is equal to or higher than a predetermined low rotation speed, the deceleration engagement hydraulic pressure supply means supplies the clutch. The engaging hydraulic pressure for deceleration is supplied to. As a result, the pump of the fluid coupling of the automatic transmission and the turbine are connected by the clutch.

Preferably, prior to the supply of the engagement hydraulic pressure for deceleration, when the vehicle enters the deceleration state, the hydraulic pressure is first discharged from the clutch by the hydraulic pressure discharging means to bring the clutch into a non-direct connection state, whereby the deceleration state is entered. It is possible to prevent a shock from being generated in the automatic transmission due to the transmission of the engine speed variation to the automatic transmission. Next, the predetermined hydraulic pressure supply means supplies a predetermined hydraulic pressure to the clutch so that the pump and the turbine are in a state immediately before engagement, and the clutch non-direct connection state for preventing a shock is quickly eliminated.

Next, the engagement hydraulic pressure supplied to the clutch is feedback-controlled by the feedback control means so that the difference between the pump rotation speed and the turbine rotation speed becomes a desired value. Here, the engagement hydraulic pressure for deceleration is
It is used as the initial value of the engagement hydraulic pressure at the start of the feedback control. If the rate of change in vehicle speed during feedback control is within a predetermined range and the vehicle is not decelerating on a steep downhill, the engagement hydraulic pressure during deceleration as the initial value of the engagement hydraulic pressure is learned by the learning correction means. This is corrected, and thereby the initial value of the engagement hydraulic pressure at the start of the next deceleration operation is optimized. On the other hand, if the vehicle body speed change rate is outside the predetermined range and the vehicle is decelerating at a steep downhill or the like, learning correction of the initial value of the engagement hydraulic pressure is prohibited. As a result, the excessive correction of the initial value of the engagement hydraulic pressure, which occurs when the learning correction is performed on a steep downhill where the engagement hydraulic pressure increases compared to when traveling on a flat road, is prevented. , Even if the vehicle is suddenly braked on a low μ road, it is maintained at an appropriate value so that engine stall does not occur.

Preferably, the vehicle body speed change rate is obtained in accordance with an output value from at least one of the vehicle speed detecting means, the lateral acceleration detecting means, the wheel speed detecting means, the longitudinal acceleration detecting means and the road surface gradient detecting means. Thus, it is possible to reliably detect whether or not the vehicle is decelerating on a steep downhill or the like. Preferably, when it is determined by the measurement of the time measuring means that the first and second predetermined times have elapsed since the feedback control was started, the first and the second hydraulic pressure values representing the hydraulic pressure supplied to the clutch at the respective determination times are determined. The second hydraulic pressure value is detected by each of the first and second hydraulic pressure value detecting means, and the difference between the first hydraulic pressure value and the second hydraulic pressure value is calculated by the hydraulic pressure difference calculating means,
The learning correction means suitably corrects the initial oil pressure for deceleration in accordance with this oil pressure difference.

[0016] Preferably, when the hydraulic pressure difference is outside the predetermined range, the feedback control canceling means cancels the feedback control and discharges the hydraulic pressure from the clutch, whereby the feedback control corrects the excessive increase in the hydraulic pressure supplied to the clutch. It is possible to prevent the occurrence of a shock caused by the above, and the engine stall due to the sudden braking during the feedback control started with the excessive initial value of the clutch supply oil pressure.

Preferably, the hydraulic pressure supply to the clutch and the hydraulic pressure discharge from the clutch are performed at a duty ratio given to an electromagnetic valve of the clutch control device, and the hydraulic pressure supplied to the clutch is duty-controlled by this electromagnetic valve. The clutch hydraulic pressure control is properly performed.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An automatic transmission for a vehicle equipped with a clutch control device according to an embodiment of the present invention will be described below. As shown in FIG. 1, the automatic transmission of this embodiment includes a casing 20A, a pump 23, a stator 24, and a turbine 25.
A torque converter 20 as a fluid coupling including the above and a gear transmission 30 as an auxiliary transmission are provided.

Drive shaft 21 in torque converter 20
One end of the internal combustion engine 1 via the flywheel 11.
0 is connected to the crankshaft 10A of the drive shaft 21 via the casing 22 of the torque converter 20.
Is connected to the other end. The stator 24 is connected to the casing 20A via a one-way clutch 24A, and the turbine 25 is connected to the input shaft 30A of the gear transmission 30.
Are linked to.

The gear transmission 30 includes, for example, a planetary gear mechanism (not shown) including a sun gear, a planetary carrier, and a ring gear as rotating elements, and a friction engagement element (for permitting or blocking the rotating operation of these rotating elements). It has a multi-plate clutch and a brake (not shown) as speed change elements, and each speed change element has an engagement piston device or a servo device.

The torque converter 20 further includes a slip-type direct coupling clutch (hereinafter referred to as a damper clutch) 28 for rigidly connecting an input shaft and an output shaft of the torque converter 20. The damper clutch 28 is interposed between the damper clutch input casing 22 and the turbine 25, and mechanically directly connects the pump 23 and the turbine 25 while allowing a required slip even when engaged (when directly connected). It is like this.

The automatic transmission includes a storage device, a central processing unit,
A transmission control unit (hereinafter referred to as "I / O interface", counter, etc.)
16), and a hydraulic circuit 40 for driving and controlling the gear transmission 30 under the control of the TCU 16. The hydraulic circuit 40 includes a manual valve (not shown) that responds to a select lever operation by a driver,
It has various control valves (not shown) for switching the line pressure supply path to the speed change element of the gear transmission 30 and controlling the magnitude of the supplied hydraulic pressure.

An electromagnetic pickup 14 serving as an engine speed sensor for detecting the internal combustion engine speed NE is connected to the input side of the TCU 16, and the electromagnetic pickup 14 is fitted onto the flywheel 11 and is outside the starter 1.
Ring gear 1 with a predetermined number of teeth that meshes with two pinions 12A
It is arranged to face 1A. Further, on the input side of the TCU 16, a turbine rotation speed sensor 15 for detecting the turbine rotation speed NT and a transfer drive gear rotation speed N are provided.
A valve opening θ of a throttle valve (not shown), which is connected to a transfer drive gear rotation speed sensor 17 for detecting O, is arranged in the intake passage of the internal combustion engine 10.
A throttle opening sensor 18 for detecting T, and a temperature TOIL of hydraulic oil discharged from a hydraulic pump (not shown).
The oil temperature sensor 19 for detecting is connected.

The automatic transmission further includes a damper clutch hydraulic control circuit 50 for controlling direct connection, non-direct connection, slip direct connection and deceleration direct connection of the damper clutch 28. The damper clutch hydraulic control circuit 50 includes a damper clutch control valve 52 for switching the hydraulic oil supply passage to the damper clutch 28 and controlling the hydraulic pressure acting on the clutch 28, and a damper composed of a normally-closed on / off valve. Clutch control solenoid valve 54
And the solenoid 54A of the valve 54 is TCU1.
6 is connected to the output side.

More specifically, the damper clutch control valve 52 includes a spool 52A, a left end chamber 52B for accommodating the left end of the spool 52A, and a spring 52C for pressing the spool 52A rightward in FIG. A pilot oil passage 55 communicating with a pilot hydraulic pressure source (not shown) is connected to 52B. The damper clutch control solenoid valve 54 is connected to the branch passage 55A connected to the pilot oil passage 55 and communicating with the drain side.
Is installed, and the magnitude of the pilot hydraulic pressure supplied to the left end chamber 52B is controlled by opening and closing the valve 54. Further, a pilot hydraulic pressure source supplies hydraulic pressure to the right end chamber 52D into which the right end of the spool 52A can freely enter.

The damper clutch hydraulic control circuit 5 having the above structure
At 0, when the pilot oil pressure acts on the left end chamber 52B and the spool 52A moves to the right limit position, the lubricating oil pressure supplied to the torque converter 20 passes through the oil passage 56, the damper clutch control valve 52, and the oil passage 57. , Is supplied to the hydraulic chamber defined by the input casing 22 and the damper clutch 28, whereby the engagement of the damper clutch 28 is released.

On the other hand, when the pilot hydraulic pressure is not supplied to the left end chamber 52B and the spool 52A moves to the left limit position,
The line pressure from the hydraulic pump is supplied to the hydraulic chamber defined by the damper clutch 28 and the turbine 25 via the oil passage 58, the damper clutch control valve 52 and the oil passage 59, whereby the damper clutch 28 is casing. Frictionally engage 22.

When the duty of the damper clutch control solenoid valve 54 is controlled by the TCU 16, the pilot hydraulic pressure acting on the left end chamber 52B and the spring 5 are applied.
The spool 52 is moved to a position where the resultant force of the spring force of 2C and the pilot hydraulic pressure acting on the right end chamber 52C are balanced.
When A moves, the hydraulic pressure corresponding to this spool movement position is supplied to the damper clutch 28, and the transmission torque via the damper clutch 28 is controlled to a required value.

The operation of the automatic transmission having the above structure will be described below. When the engine 10 is started, shift control and clutch control by the hydraulic circuit 40 and the damper clutch hydraulic control circuit 50, which operate under the control of the TCU 16, are started. The shift control is performed as conventionally known. Briefly described, because of this shift control, the TCU 16 turns NO.
The optimum gear position is determined based on the transfer drive gear rotation speed NO that is detected by the sensor 17 and represents the vehicle speed, the throttle valve opening degree θT that is detected by the θT sensor 18, and the gear position currently established in the gear transmission 30. Is different from the optimum shift speed, a shift command is sent to various control valves of the hydraulic circuit 40. Then, by the operation of various control valves in response to the gear shift command, the hydraulic pressure supply path to the gear shift element of the gear transmission 30 is switched, and the operating state of the rotary element of the gear shift apparatus is switched, thereby establishing the optimum gear stage. .

On the other hand, in connection with clutch control, TCU1
6 shows the current vehicle operating state represented by the turbine rotational speed NT detected by the NT sensor 15, the throttle valve opening θT detected by the θT sensor 18, and the like.
A clutch control area determination routine (not shown) for determining which of the clutch control areas divided as shown in FIG.

Referring to FIG. 2, the entire clutch control region is divided into four regions, a complete direct connection region, a non-direct connection region, a slip direct connection region and a deceleration direct connection region, depending on the turbine rotation speed NT and the throttle valve opening θT. There is. If it is determined in the determination routine that the current vehicle operating state is in the complete direct coupling range, the TCU 16 sets the duty ratio of the normally closed damper clutch control solenoid valve 54 to 10%.
A control output for opening the valve 54 as a value at or near 0% is sent to the solenoid 54A of the valve 54. As a result, the damper clutch control valve 52
Of the pilot hydraulic pressure to the left end chamber 52B of the
The spool 52A is located at the extreme left position, whereby the line pressure from the oil passage 58 is supplied as the apply pressure to the damper clutch 28 via the oil passage 59, while the release side hydraulic oil of the damper clutch 28 is fed to the oil passage. It is discharged via 57. As a result, the damper clutch 28 is attached to the casing 22.
The pump 23 and the turbine 25 are directly connected to each other by mechanical frictional engagement.

When the TCU 16 determines that the vehicle is operating in the non-direct coupling region, the duty ratio of the damper clutch control solenoid valve 54 is set to 0 to 30% and the control output for closing the valve 54 is output to the solenoid 54A.
Send to. As a result, the pilot oil pressure is supplied to the left end chamber 52B of the damper clutch control valve 52, and the spool 52A takes the right limit position, whereby
The line pressure from the oil passage 58 is supplied as release pressure to the damper clutch 28 via the oil passage 57, while the apply-side hydraulic oil of the damper clutch 28 is discharged via the oil passage 59. As a result, mechanical frictional engagement between the damper clutch 28 and the casing 22, and by extension, the pump 23 and the turbine 2
5 is released from the direct connection with the pump 23 and the turbine 25.
Are in fluid friction engagement.

When the TCU 16 determines that the vehicle operating condition is in the slip direct connection region, the TCU 16 duty-controls the clutch control solenoid valve 54 so that the required apply pressure and release pressure are applied to the damper clutch 28. As a result, the damper clutch 28 is directly connected to the casing 22 in a required slip state.
Also in the deceleration direct connection region, the duty control of the clutch control solenoid valve 54 is performed by the TCU 16 to adjust the apply pressure and the release pressure to the damper clutch 28.

Hereinafter, the deceleration direct connection control by the clutch control device of the present embodiment will be described in detail with reference to FIGS. During the vehicle operation, the TCU 16 determines which of the four clutch control areas shown in FIG. 2 the current vehicle operation state, which is represented by the turbine rotation speed NT and the throttle valve opening θT, in the clutch control area determination routine described above. Determine whether to do.

When the turbine rotational speed NT is equal to or higher than a predetermined rotational speed, for example 1200 rpm, and the throttle valve opening θT is equal to or greater than a predetermined angle, it is determined that the vehicle operating state is in the deceleration direct connection region. The deceleration direct connection control routine of FIG. 6 is started. In this deceleration direct connection control routine, the TCU 16 sets the turbine rotation speed NT and the throttle valve opening θT at the time point of the deceleration direct connection region determination to T
It is stored in a register (not shown) built into the CU 16, and then the damper clutch control solenoid valve 54
The control output for closing the valve 54 with the duty ratio of 0% is sent to the solenoid 54A of the valve 54 for t1 seconds (for example, one operation cycle time 655 ms) (step S2). As a result, in section A of FIG.
Apply pressure to the damper clutch 28 is 0% duty ratio
The damper clutch 28 is brought into the non-direct connection state by holding the value corresponding to the above, and therefore the pump 23 and the turbine 25 are brought into the non-direct connection state.

Thus, in step S2, T
The CU 16 cooperates with the valve 54 and the like to function as a means for discharging the hydraulic pressure from the damper clutch 28 when the vehicle enters the decelerating operation state, so that the pump 23 and the turbine 25 immediately when the vehicle enters the deceleration direct connection area. Since the non-direct connection state is set, the torque fluctuation of the engine 10 due to the returning operation of the throttle valve is not directly transmitted to the gear transmission 30 via the pump 23 and the turbine 25. In other words, the engine output torque fluctuation at the start of the deceleration operation of the vehicle is absorbed by the working fluid interposed between the pump 23 and the turbine 25, so that the damper clutch 28 is brought into the direct engagement state immediately before entering the deceleration direct engagement area. Even if there is, shock or judder due to torque fluctuation transmission does not occur.

When the sending of the control output to the solenoid 54A for t1 seconds is completed, the TCU 16 determines whether the vehicle operating condition is still in the deceleration direct connection region (step S3). If this determination result is negative, TCU1
6 resets flags F1, F2 and F3 having a control index function described later to the value "0", respectively,
A control output for setting the duty ratio of No. 4 to 0% is sent to the solenoid 54A (step S4), and this control routine ends.

On the other hand, when it is determined in step S3 that the current vehicle operating condition is in the deceleration direct connection region, the TCU 16 reads out the turbine rotational speed NT and the throttle valve opening θT stored in step S1 from the register and stores them in the memory in advance. With reference to the stored "gatta hydraulic pressure map" (FIG. 8), the duty ratio DG1 (%) for generating the gamut hydraulic pressure corresponding to both parameter values NT and θT is obtained, and further, the valve A control output for setting the duty ratio of 54 to DG1 is sent to the solenoid 54A for t2 seconds (for example, one operation cycle time 655 ms) (step S5). As a result, in the section B of FIG. 7, the apply pressure corresponding to the duty ratio DG1 is applied to the damper clutch 28, and the damper clutch 28 is brought into the direct connection state.

As shown in FIG. 8, in the rattling oil pressure map, 16 NT / θT regions divided by the turbine speed NT and the throttle valve opening θT are realized in step S2. The duty ratios A1 to A16 (that is, the duty ratio DG1 for generating the hydraulic pressure) are set so that the non-direct connection state can be quickly eliminated. In the setting of the duty ratios A1 to A16, the operating state of the damper clutch 28 immediately before the entry into the deceleration direct connection region is taken into consideration. That is, the duty ratio A16 and the like used at the time of transition from the complete direct coupling range in which both the throttle valve opening θT and the turbine rotation speed NT are large are set to a small value in consideration of the residual pressure on the damper clutch apply side. The duty ratio A1 and the like used when shifting from the non-direct connection region where the turbine rotation speed NT is small is set to a larger value as the throttle valve opening θT is smaller.

In step S5, the TCU 16
Sends a control output to the solenoid 54A for t2 seconds, thereby functioning as a means for supplying a predetermined hydraulic pressure (stuttering hydraulic pressure) to the damper clutch 28 so as to bring the pump 23 and the turbine 25 into a state immediately before engagement. .
When the transmission of the control output is completed, the TCU 16 determines whether the vehicle operating state is still in the deceleration direct connection area (step S6). If the determination result is negative, the flags F1, F2 and F3 are respectively set. The value is reset to "0" and a control output for setting the duty ratio of the valve 54 to 0% is sent to the solenoid 54A (step S
4) The control routine is finished.

On the other hand, when it is determined in step S6 that the current vehicle operating condition is in the deceleration direct connection region, the TCU 16 reads out the turbine rotational speed NT and the throttle valve opening θT stored in step S1 from the register and stores them in the memory in advance. Referring to the stored feedback start oil pressure map (FIG. 9), the duty ratio DG2 for generating the feedback start oil pressure corresponding to both parameter values NT and θT.
(%) Is set as an initial value of the variable duty ratio DG3 for feedback control, and further, a control output for setting the duty ratio of the valve 54 to DG3 is sent to the solenoid 54A, and at the same time from the feedback control start time point. A timer (not shown) as a time measuring means for measuring the elapsed time is started (step S7).

As shown in FIG. 9, in the feedback start oil pressure map, the duty of the valve 54 is controlled by feedback control for 16 NT / θT regions divided by the turbine speed NT and the throttle valve opening θT. Duty ratios B1 to
B16 is set for each. Then, in the setting of the duty ratios B1 to B16, the operating state of the damper clutch 28 immediately before the entry into the deceleration direct connection region is taken into consideration. That is,
The duty ratio B16 or the like used when shifting from the completely direct coupling region where both the throttle valve opening θT and the turbine rotational speed NT are large is a non-direct coupling region where the turbine rotational speed NT is small in consideration of the residual pressure on the damper clutch apply side. Is set to a value larger than the duty ratio B13 or the like used when shifting from. The duty ratios B1 to B16
Is increased or decreased by the learning correction described later, but initially,
It is set to a low value so that engine stall does not occur even when sudden braking is performed on a low μ road.

The TCU 16 and the like, in step S7,
The clutch damper 28 functions as a means for supplying deceleration engagement hydraulic pressure, and also starts to function as a means for feedback controlling the deceleration engagement hydraulic pressure as an initial value. Feedback control is started in section C of 7. In step S8,
The TCU 16 refers to the timer output and determines whether or not t3 seconds (for example, 1 second) as the first predetermined time has elapsed from the feedback control start time. Immediately after the feedback control is started, the determination result of step S8 is negative, and in this case, it is further determined whether or not t4 seconds (for example, 2.5 seconds) have elapsed from the feedback control start time (step S9). Immediately after the feedback control is started, this determination result is negative, so it is determined whether or not the vehicle operating state is still in the deceleration direct connection area (step S).
10).

If it is determined in step S10 that the deceleration is not directly connected, the TCU 16 resets the flags F1 to F3, respectively, and sends a control output to the solenoid 54A to set the duty ratio of the valve 54 to 0% ( Step S11). On the other hand, if it is determined that the deceleration is directly connected, TC
U16 reads the output indicating the vehicle speed V from the NO sensor 17 as the vehicle speed detecting means (step S12),
The NO sensor output stored in the first vehicle speed data area in the previous vehicle speed data storage cycle is transferred to the second vehicle speed data area, and the N read in step S12 of the current cycle is read.
The O sensor output is stored in the first vehicle speed data area (step S13), and the vehicle speed change rate ΔV is calculated from both NO sensor outputs.
Is calculated (step S14).

Next, the TCU 16 determines whether or not the vehicle speed change rate ΔV calculated in step S14 is within a predetermined range that is, for example, larger than −10 km / h · s and smaller than 7 km / h · s. If the determination result is negative (step S15), that is, if the vehicle is decelerating on a steep downhill or a steep uphill, the flag F3 is set to decelerate on a steep downhill or a steep uphill. The value "1" is set (step S16).

In step S17 following step S15 or S16, the TCU 16 determines the engine speed NE.
The actual slip amount (NE-NT) in the damper clutch 28 is calculated from the output of the NE sensor 14 representing the above and the output of the NT sensor 17 representing the turbine speed NT, and the target slip amount during deceleration operation (for example, -5 rotations) is calculated. A value obtained by reading out from the memory and then subtracting the target slip amount from the actual slip amount is the discrimination reference value “−a” (where a>
It is determined whether it is smaller than 0).

If the determination result in step S17 is affirmative, that is, if the actual slip amount is smaller than the level at which the actual slip amount is lower than the target slip amount by the value "a", the TCU is set.
The control unit 16 determines that the apply pressure to the damper clutch 28 is too low, and updates the variable duty ratio DG3 to a value obtained by adding the predetermined value d1 to the variable duty ratio DG3 (step S18). As a result, the apply pressure to the damper clutch 28 increases. Next, it is determined whether or not the flag F1 has the value "1" (step S1).
9). If t3 seconds have not elapsed from the feedback control start time point, the determination result in step S19 is negative, and in this case, the process returns to step S8.

On the other hand, if the value obtained by subtracting the target slip amount from the actual slip amount is not smaller than the judgment reference value "-a" in step S17, the TCU 16 subtracts the target slip amount from the actual slip amount. It is further determined whether or not the obtained value is larger than the determination reference value "b" (here, b> 0) (step S20). If this determination result is affirmative, that is, if it is determined that the apply pressure to the damper clutch 28 is excessive, the variable duty ratio DG3 is decreased so that the predetermined value d2 is subtracted from the variable duty ratio DG3. Is updated (step S2
1). Next, it is determined whether or not the flag F1 has the value "1" (step S22), and if the determination result is negative, the process returns to step S8.

Further, in step S20, the value obtained by subtracting the target slip amount from the actual slip amount is not larger than the discrimination reference value "b", so that the actual slip amount and thus the apply pressure to the damper clutch 28 is in the proper range. If it is determined that the flag F1 is within the range, it is determined in step S23 whether or not the flag F1 has the value "1". If the determination result is negative, the process returns to step S8.

As described above, the feedback control for correcting or maintaining the duty ratio of the clutch control solenoid valve 54 is increased or decreased so that the slip amount of the damper clutch 28 falls within the proper range. After that, from the start of feedback control, the first
When it is determined in step S8 that t3 seconds, which is the predetermined time, has elapsed, the TCU 16 as the first hydraulic pressure value detection means sets the duty ratio DG3, which is being sent as a control output to the valve 54 at that time, to the first duty ratio DG3. The duty ratio D1 corresponding to the hydraulic pressure (first hydraulic pressure value) supplied to the clutch when the predetermined time has elapsed is read and stored in the memory (step S24), and then the first predetermined time elapses and the first In order to store the detection completion of the hydraulic pressure value, the flag F
1 is set to the value "1" (step S25), and the control processing after step S9 is executed.

During the execution of this feedback control, if it is determined in step S19, S22 or S23 that the value of the flag F1 is "1", steps S26 and S27.
Alternatively, in S28, it is further determined whether or not the value of the flag F2 is "1". If t4 seconds, which is the second predetermined time, has not elapsed from the feedback start time, the determination result in step S26, S27, or S28 is negative, and in this case, the control processing of step S9 and thereafter is executed.

After that, when it is determined in step S9 that t4 seconds as the second predetermined time has elapsed from the feedback control start time, the TCU 16 as the second hydraulic pressure value detecting means outputs a control output to the valve 54 at that time. The sent duty ratio DG3 is read as the duty ratio D2 corresponding to the hydraulic pressure supplied to the clutch (second hydraulic pressure value) at the time when the second predetermined time has elapsed, and this is stored in the memory (step S29). Then, the flag F2 is set to the value "1" in order to store the elapse of the second predetermined time and the detection completion of the second hydraulic pressure value (step S30).

Then, the TCU 1 as the hydraulic pressure difference calculating means
Reference numeral 6 is a duty ratio D1 and D2 as the first and second hydraulic pressure values read from the memory and subtracts the duty ratio D1 from the duty ratio D2, whereby a duty ratio representing the difference between the first hydraulic pressure value and the second hydraulic pressure value. The rate change amount ΔD is calculated (step S31), and the duty ratio correction amount β corresponding to the calculated duty ratio change amount ΔD is obtained by referring to the duty ratio change amount / duty ratio correction amount map (FIG. 10) ( Step S32).

As shown in FIG. 10, the duty ratio correction amount β is set so as to change stepwise according to the increase or decrease of the duty ratio change amount ΔD. Specifically, after the feedback control is started, when the duty ratio increases by 0% to 0.4% from the time t3 seconds to the time t4 seconds, the duty ratio is not corrected and the duty ratio is 0.4%. When the duty ratio is increased by 1.2%, the duty ratio is increased by 0.4%. When the duty ratio is increased by 1.2% or 1.6%, the duty ratio is increased by 1.2%. If the duty ratio increases by 1.6% or more, the duty ratio is increased by 1.6% and corrected. By setting the duty ratio correction amount β as described above, it is possible to prevent the duty ratio from being excessively increased and corrected, thereby preventing an engine stall.

The same applies to the duty ratio decrease correction when the duty ratio is decreased. Next, TC
U16 determines whether or not the value of the flag F3 is "1" (step S33), and the determination result is negative, that is, the vehicle body change rate ΔV is within the predetermined range, and therefore the vehicle is suddenly changed. If it is determined that the vehicle is not traveling on a downhill or a steep uphill, the feedback start duty ratio DG2
(More specifically, the duty ratios B1 to B1 set in the map of FIG. 9 for each of the 16 NT / θT regions
The feedback start duty ratio DG2 is updated to a value obtained by adding the correction amount β obtained in step S32 to B16) (step S34). That is, T as learning correction means
The duty ratio DG2 is learned by the CU 16.

On the other hand, if the value of the flag F3 is "1",
When it is determined that the vehicle is traveling on a steep downhill or a steep uphill (more generally, a road surface that may cause inappropriate learning correction), step S34 is skipped, and thus, Learning of the feedback start duty ratio DG2 on a steep downhill is prohibited, and it is reliably prevented that the duty ratio DG2 becomes excessively large due to learning of the duty ratio DG2 on a steep downhill.

In step S35, it is determined whether the duty ratio change amount ΔD is larger than the determination reference value C (> 0). If the result of the determination is negative, the duty ratio change amount ΔD is the determination reference value “D”. It is further determined whether or not it is smaller than "-f"(f> 0) (step S36). Then, if the determination result in step S36 is negative, step S10
The following control processing is executed.

On the other hand, if the determination result in step S35 or S36 is affirmative, the TCU 16 as the feedback control stopping means resets the flags F1 to F3 and outputs a control output that sets the duty ratio of the valve 54 to 0%. To the solenoid 54A (step S3
7) The control routine is finished. That is, when the determination result of step S35 is affirmative and the duty ratio of the valve 54 is the determination reference value C from the time t3 seconds have elapsed to the time t4 seconds have elapsed since the feedback was started.
When the feedback control is continued, it is determined that the duty ratio of the valve 54 and the apply pressure to the damper clutch 28 becomes excessive when the feedback control is continued, and the feedback control is stopped. The reason for this is that if feedback control is continued when there is a large amount of increase in the duty ratio from the time point t3 seconds to the time point t4 seconds, the actual slip amount at a certain point (for example, 10 seconds after the feedback control starts). This is because there is a risk of causing a sudden change in the actual slip amount such that the sign of the deviation between the target slip amount and the target slip amount suddenly reverses, and eventually causing a shock in the automatic transmission.

If the determination result in step S36 is affirmative and the duty ratio change amount ΔD from the time t3 seconds to the time t4 seconds is less than the determination reference value "-f", the feedback start duty is set. If the duty ratio was too large and sudden braking is performed on the low μ road before the optimization of the duty ratio by the reduction correction is not completed, an engine stall may be caused due to the delay in releasing the direct connection state of the damper clutch 28. May occur. Therefore, if the amount of decrease in the duty ratio is too large, the feedback control is stopped to prevent such a problem.

The damper clutch 2 under deceleration direct coupling control
The appropriate range of the apply pressure to 8 (duty ratio of the valve 54) is relatively strict and needs to be within an error range of, for example, about ± 5% with respect to the convergent apply pressure by the feedback control. That is, when the apply pressure is higher than the convergent apply pressure by, for example, 5% or more, the sudden stall on the low μ road causes the engine stall due to the delay in releasing the direct connection state of the damper clutch 28, while the apply pressure is increased. Is less than the convergent apply pressure by, for example, 5% or more,
This is because the damper clutch 28 is in a non-directly connected state and the engine speed is likely to suddenly decrease. Therefore, fuel cut is stopped to prevent engine stall, and thus fuel efficiency cannot be improved by directly connecting the clutch. According to the clutch control device of the present embodiment, the feedback start duty ratio is properly learned and corrected to satisfy the above requirement.

The present invention is not limited to the above embodiment, but can be variously modified. For example, in the embodiment, the vehicle speed change rate Δ obtained from the output of the NO sensor 17 as the vehicle speed detecting means.
V is detected as the vehicle body speed change rate, and the learning correction of the duty ratio is selectively performed according to the detection result.
Instead of or in addition to the vehicle speed detecting means, at least one of lateral acceleration detecting means, wheel speed detecting means, longitudinal acceleration detecting means and road surface gradient detecting means is provided, and an output value from at least one of these detecting means is provided. The vehicle body speed change rate may be obtained according to

Further, in the embodiment, the operation is started based on any one of the feedback start duty ratios B1 to B16 set for each of the 16 NT / θT regions in the feedback start oil pressure map shown in FIG. The correction amount β is calculated according to the duty ratio change rate ΔD detected during the execution of the feedback control, and all the duty ratios B1 to B16 are collectively learned and corrected by the correction amount β, but the feedback start duty ratio B1 to B
Of the sixteen, only one actually used at the start of the feedback control may be learned and corrected by the correction amount β.

[0063]

As described above, from the pump connected between the engine and the auxiliary transmission of the automatic transmission and connected to the output side of the engine, and the turbine connected to the input side of the auxiliary transmission. In a fluid coupling of an automatic transmission for a vehicle, the clutch control device of the present invention has a clutch capable of disconnecting and connecting the pump and the turbine, and controls the hydraulic pressure supplied to the clutch according to the vehicle operating state. A driving state detecting means for detecting a vehicle driving state, and a deceleration engaging hydraulic pressure for supplying a deceleration engaging hydraulic pressure to the clutch when the driving state detecting means detects that the vehicle has entered a decelerating state. Feedback control is performed with the engagement hydraulic pressure during deceleration as the initial value so that the difference between the rotational speed of the pump detected by the operating condition detection means and the rotational speed of the turbine becomes desired. Feedback control means for controlling the vehicle speed and learning correction means for learning and correcting the initial value only when the driving state detecting means detects that the vehicle body speed change rate is within a predetermined range. At some times, the damper clutch can be directly connected and learning can be performed to make the clutch hydraulic pressure appropriate, and moreover, it is possible to reliably prevent the clutch hydraulic pressure from becoming excessive by learning. It is possible to prevent the release delay of the direct connection state of the engine and eventually the engine stall. Therefore, the fuel supply to the engine can be cut during the decelerating operation of the vehicle without causing the engine stall even during the sudden braking on the low μ road, thereby improving the fuel consumption.

According to a particular aspect of the present invention, the deceleration range regarded as a deceleration state is set to a range in which the engine load is low and the turbine rotation speed is equal to or higher than a predetermined low rotation speed. Direct connection control can be executed in an appropriate area. Further, according to a preferred aspect of the present invention, the clutch control device includes hydraulic pressure discharging means for discharging hydraulic pressure from the clutch when it is detected that the vehicle enters a deceleration state, and a pump and a pump after the hydraulic pressure is discharged by the hydraulic pressure discharging means. Since a predetermined hydraulic pressure supply means for supplying a predetermined hydraulic pressure to the clutch is further provided so that the turbine is in a state immediately before engagement, and the deceleration engagement hydraulic pressure is supplied after the predetermined hydraulic pressure is output, so that when the deceleration state is entered. It is possible to prevent a shock from occurring in the automatic transmission due to the transmission of engine speed fluctuations to the automatic transmission, and to quickly eliminate the clutch non-direct connection state to prevent this shock and smoothly start feedback control. It will be possible.

According to a preferred aspect of the present invention, the clutch control device includes a clock means for measuring an elapsed time from the start of the feedback control, and a clutch when the first predetermined time has elapsed from the start of the feedback control. First oil pressure value detecting means for detecting a first oil pressure value representing a hydraulic pressure value supplied to
Second hydraulic pressure value detecting means for detecting a second hydraulic pressure value representing a hydraulic pressure value supplied to the clutch when a second predetermined time set longer than the first predetermined time has elapsed since the feedback control was started; The learning correction means corrects the initial hydraulic pressure for deceleration according to the hydraulic pressure difference, so that the learning correction can be properly performed.

According to the aspect including the feedback control stopping means for stopping the feedback control and discharging the oil pressure from the clutch when the oil pressure difference is out of the predetermined range, the shock resulting from the excessive increase correction of the clutch supply oil pressure by the feedback control is provided. It is possible to prevent engine stall from occurring and due to sudden braking during feedback control that is started with an excessively large initial value of the clutch supply hydraulic pressure.

In a preferred mode of the present invention, the driving state detecting means includes at least one of a vehicle speed detecting means, a lateral acceleration detecting means, a wheel speed detecting means, a longitudinal acceleration detecting means and a road surface slope detecting means, and the vehicle body speed change is performed. Since the rate is calculated according to the output value from at least one detection means, it is possible to determine whether the vehicle is decelerating on a road surface where inappropriate learning correction may be performed, such as a steep downhill. Can be detected.

According to the aspect in which the solenoid valve for duty-controlling the hydraulic pressure supplied to the clutch is provided and the hydraulic pressure is supplied to the clutch and discharged from the clutch at the duty ratio given to the solenoid valve, the clutch hydraulic pressure control is performed. Can be done properly.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a main part of an automatic transmission for a vehicle equipped with a clutch control device according to an embodiment of the present invention.

FIG. 2 is a diagram showing setting examples of a complete direct coupling area, a non-direct coupling area, a slip direct coupling area, and a deceleration direct coupling area, which are related to the operation control of the damper clutch of FIG.

[FIG. 3] FIG.
Transmission Control Unit (TCU)
4 is a flowchart showing a part of a deceleration direct connection control routine executed by

FIG. 4 is a flowchart showing another part of a deceleration direct connection control routine.

FIG. 5 is a flowchart showing yet another part of a deceleration direct connection control routine.

FIG. 6 is a flowchart showing the rest of the deceleration direct connection control routine.

FIG. 7 is a graph showing a change in duty ratio of a damper clutch control solenoid valve with the passage of time during deceleration direct coupling control of the damper clutch.

FIG. 8 is a diagram showing a setting example of a “gattame hydraulic pressure map” used for deceleration direct connection control of a damper clutch.

FIG. 9 is a diagram showing a setting example of a feedback start oil pressure map used for deceleration direct connection control of a damper clutch.

FIG. 10 is a diagram showing a setting example of a duty ratio change amount / duty ratio correction amount map used for learning correction of a duty ratio of a damper clutch control solenoid valve.

[Explanation of symbols]

10 Internal Combustion Engine 14 Engine Speed (NE) Sensor 15 Turbine Speed (NT) Sensor 16 Transmission Control Unit (TC)
U) 17 transfer drive gear rotation speed sensor (vehicle speed sensor) 18 throttle opening sensor 20 torque converter 23 pump 25 turbine 28 damper clutch 30 gear transmission 40 hydraulic circuit 50 damper clutch hydraulic control circuit 52 damper clutch control valve 54 damper clutch control Solenoid valve

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshimasa Nagayoshi 5-3-8, Shiba, Minato-ku, Tokyo Inside Mitsubishi Motors Corporation (72) Toshinori Ishii 5-33-8, Shiba, Minato-ku, Tokyo Mitsubishi Motors Corporation (72) Inventor Yasuhiro Nakajima 5-3-8, Shiba, Minato-ku, Tokyo Mitsubishi Motors Corporation (72) Inventor Yoichi Furuichi 5-33-8, Shiba, Minato-ku, Tokyo Mitsubishi Automobile Industry Co., Ltd. (72) Inventor Toshimitsu Yamamoto 1-13 13 Sadamoto-cho, Himeji City, Hyogo Prefecture Mitsubishi Electric Control Software Co., Ltd.

Claims (7)

[Claims] 1. A vehicle comprising a pump connected between the engine and an auxiliary transmission of an automatic transmission and connected to the output side of the engine, and a turbine connected to the input side of the auxiliary transmission. A fluid coupling clutch control device for a fluid coupling of an automatic transmission, comprising a clutch capable of disconnecting and connecting the pump and the turbine, and controlling a hydraulic pressure supplied to the clutch according to a vehicle operating state. A driving state detecting means for detecting a vehicle driving state, and a deceleration function for supplying deceleration engaging hydraulic pressure to the clutch when the driving state detecting means detects that the vehicle has entered a deceleration state. The engaging hydraulic pressure during deceleration so that the difference between the rotational speed of the pump detected by the combined hydraulic pressure supply means and the rotational speed of the pump detected by the operating state detection means becomes a desired value. Feedback control means for performing feedback control as an initial value, and learning correction means for learning and correcting the initial value only when the driving state detection means detects that the vehicle body speed change rate is within a predetermined range. A clutch control device for a fluid coupling of an automatic transmission for a vehicle, comprising: 2. The deceleration range regarded as the deceleration state is set to a range in which the load on the engine is low and the rotation speed of the turbine is equal to or higher than a predetermined low rotation speed. Item 1. A clutch control device for a fluid coupling of an automatic transmission for a vehicle according to Item 1. 3. The clutch control device includes hydraulic pressure discharging means for discharging hydraulic pressure from the clutch when it is detected that the deceleration state is entered, and the pump and the turbine after the hydraulic pressure is discharged by the hydraulic pressure discharging means. A predetermined hydraulic pressure supply means for supplying a predetermined hydraulic pressure to the clutch so as to be in a state immediately before engagement, wherein the deceleration engagement hydraulic pressure is supplied after the predetermined hydraulic pressure is output. Item 3. A clutch control device for a fluid coupling of an automatic transmission for vehicles according to Item 1 or 2. 4. The clutch control device comprises a time measuring means for measuring an elapsed time from the start of the feedback control, and a hydraulic pressure supplied to the clutch when a first predetermined time has elapsed from the start of the feedback control. A first hydraulic pressure value detecting means for detecting a first hydraulic pressure value representing a value, and a second predetermined time period set to be longer than the first predetermined time period for the clutch when the feedback control is started. The learning correction means further includes: a second hydraulic pressure value detecting means for detecting a second hydraulic pressure value representing a supply hydraulic pressure value; and a hydraulic pressure difference calculating means for calculating a difference between the first hydraulic pressure value and the second hydraulic pressure value. The clutch control device for a fluid coupling of an automatic transmission for a vehicle according to claim 1, wherein the initial hydraulic pressure for deceleration is corrected according to the hydraulic pressure difference. 5. The clutch control device further comprises feedback control canceling means for canceling the feedback control and discharging the hydraulic pressure from the clutch when the hydraulic pressure difference is outside a predetermined range. A clutch control device for a fluid coupling of an automatic transmission for a vehicle according to claim 1. 6. The driving state detecting means includes at least one of a vehicle speed detecting means, a lateral acceleration detecting means, a wheel speed detecting means, a longitudinal acceleration detecting means, and a road surface gradient detecting means, and the vehicle body speed change rate is the above-mentioned. The clutch control device for a fluid coupling of an automatic transmission for a vehicle according to any one of claims 1 to 5, wherein the clutch control device is obtained according to an output value from at least one detecting means. 7. The clutch control device further includes an electromagnetic valve for duty-controlling a hydraulic pressure supplied to the clutch, wherein the hydraulic pressure supplied to the clutch and the hydraulic pressure discharged from the clutch are applied to a duty ratio given to the electromagnetic valve. The clutch control device for a fluid coupling of an automatic transmission for a vehicle according to any one of claims 1 to 6, wherein