JPH10306870A - Coupling force control device for fluid coupling for vehicle with automatic transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent impeding of stability of PID feedback control due to the trouble of a control device and etc., and to stabilize control. SOLUTION: A coupling force control device for a fluid coupling is provided with a control means to regulate the engaging state of a lock up clutch based on the detecting results of a operation state detecting means S1 and a slip amount detecting means S5. Based on a difference es between a target slip amount RO1 decided based on the operation state of a vehicle by the control means and a detecting actual slip amount RS, and a differential value, and an integration value, a PID feedback controlled variable (f) of the regulating means is decided (S14) so that the actual slip amount is controlled to a value approximately equal to a target slip amount. Control of the regulation means is executed and when a decided controlled variable (f) exceeds a given value Ku, control of the regulation means is executed by the given value Ku. A current execution controlled variable is prevented from being reflected by the integration term of a next controlled variable.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle with an automatic transmission for duty control of a lock-up solenoid valve based on an error (deviation) of an actual slip amount with respect to a target slip amount in a slip control of a lock-up clutch. The present invention relates to a fastening force control device for a fluid joint.

[0002]

2. Description of the Related Art Generally, in a vehicle with an automatic transmission, a pump (input element) and a turbine (output element) of a torque converter (fluid coupling) are directly connected (lock-up ON).
State) or a lock-up clutch configured to be able to engage both elements in a state in which they can rotate relative to each other (slip state).

In the above-described slip control of the lock-up clutch, a lock-up solenoid valve provided in a hydraulic circuit is controlled by PID feedback control (P is proportional, I is integral, (D is an abbreviation for differentiation), for example, if a throttle sensor or other control device for detecting the throttle opening breaks down, the PID feedback control amount may become an abnormal control amount, and control stability is greatly impaired. There was a problem.

Hereinafter, this point will be described in more detail. Generally, when the driving state of the vehicle enters a predetermined lock-up slip region under the condition that the driving force is transmitted from the engine to the wheels, the lock-up occurs. Although the clutch is slipped, even in the slip range described above, lock-up occurs in a reverse driving state (engine braking state) in which the engine is rotated from the driving wheels as in a 4-3 downshift during downhill running. Usually, the slip control of the clutch is prohibited, and the lockup is completely released. That is, since the target slip amount is lost in the above-described reverse drive state, the slip control is prohibited and the lock-up is completely released because the slip control is disabled and the control becomes impossible.

Here, in order to determine the reverse driving state, a shift map is generally used in which the horizontal axis is the vehicle speed and the vertical axis is the throttle opening. For example, when the throttle is fully closed, the engine speed decreases, and Since the side is rotating, it is determined that it is in the reverse drive state, and when the accelerator pedal is depressed, the engine speed increases, so the non-reverse drive state (normal drive state in which the driving force is transmitted from the engine side to the wheel side) Becomes In short, the determination of the reverse drive state is performed depending on the magnitude of the throttle opening, and the slip control of the lock-up clutch is normally prohibited (stopped) in the reverse drive state.

However, if the throttle sensor or other control device for detecting the throttle opening described above breaks down due to disconnection or sticking, it is as if the vehicle is operating normally (wheel from the engine side) even though it is actually in the reverse drive state. It is determined that the vehicle is traveling in a driving state in which the driving force is transmitted to the side, and the slip control of the lock-up clutch may be continued. In this case, the PID feedback control amount becomes an abnormal control amount (excessive Or, the control amount becomes too small) and such control (PID feedback control)
However, there is a problem that the stability is greatly impaired.

On the other hand, a slip control device for a torque converter as described in Japanese Patent Application Laid-Open No. 61-99763 has already been invented. This control device executes feedforward control when the difference between the target slip amount and the actual slip amount is large in the slip control of the lock-up clutch,
The feedback control is executed when the difference between the target slip amount and the actual slip amount is small. However, there is no disclosure of a technical idea (corresponding means) when the PID feedback control amount becomes an abnormal value.

[0008]

According to the first aspect of the present invention, when the control amount of the PID feedback control determined based on the difference between the target slip amount and the actual slip amount is equal to or larger than a predetermined value, The control of the hydraulic circuit (adjustment means) including the duty solenoid valve is performed with a predetermined value, and the current control amount is integrated with the next control amount (I term).
The fluid coupling of the vehicle with the automatic transmission, which can prevent the stability of the PID feedback control from being impaired due to the failure of the control device or the like and stabilize the control. The purpose is to provide a force control device.

According to a second aspect of the present invention, in addition to the object of the first aspect of the present invention, when a reverse drive state (a state in which the drive wheel side rotates the engine side) in the slip control region, the target While the slip amount is held at a predetermined fastening force smaller than the slip amount (for example, held at a large fastening force such as complete fastening), when the determined PID feedback control amount is equal to or greater than a predetermined value, the adjusting means is used with the predetermined value. Is performed, and the current execution control amount is not reflected on the integral term of the next control amount. The control becomes unstable. The abnormal control amount under the reverse drive state is not reflected on the next PID feedback control amount. An object of the present invention is to provide a fastening force control device for a fluid joint of a vehicle with an automatic transmission that can stabilize control.

[0010] The invention of claim 3 of the present invention is characterized in that, in addition to the object of the invention of claim 1 or 2, the determined P
When the ID feedback control amount is equal to or more than a predetermined value, the control of the adjusting means is executed with the predetermined value, and the PID feedback control amount is determined based on the integral value used to determine the PID feedback control amount in the previous control. It is an object of the present invention to provide a fastening force control device for a fluid coupling of a vehicle with an automatic transmission, which can achieve control stabilization by determining the following.

[0011]

The invention according to claim 1 of the present invention is provided between an engine and an automatic transmission, in a state where an input element and an output element of a fluid connection are directly connected or both elements are connected to each other. A lock-up clutch configured to be engageable in a relative rotatable state, adjustment means for adjusting the engagement state of the lock-up clutch, driving state detection means for detecting a driving state of the vehicle, and the input element. A slip amount detecting means for detecting a value relating to a slip amount between the output element and a control means for controlling the adjusting means based on detection results of the operating state detecting means and the slip amount detecting means; Means for determining a target slip amount of the lock-up clutch based on the driving state of the vehicle, and calculating a difference between the determined target slip amount and the detected actual slip amount and a derivative thereof. The PID feedback control amount of the adjusting means is determined based on the partial value so that the actual slip amount approaches the target slip amount, and the control of the adjusting means is executed based on the determined PID feedback control amount, and the determined PID is controlled. When the feedback control amount is equal to or more than a predetermined value, the control of the adjusting means is executed with the predetermined value,
The present invention is characterized in that it is a fastening force control device for a fluid coupling of a vehicle with an automatic transmission that does not reflect the current execution control amount in the integral term of the next control amount.

According to a second aspect of the present invention, in addition to the configuration of the first aspect of the present invention, the lock-up clutch engagement force control characteristic provided in the control means includes a slip based on the operating state. An area in which control is performed is set. When the slip control area is in the reverse driving state, the slip amount is maintained at a predetermined engagement force smaller than the target slip amount, and the adjusting means is controlled based on the determined PID feedback control amount. Control and the determined PI
When the D feedback control amount is equal to or greater than a predetermined value, the control of the adjusting means is executed using the predetermined value, and the fluid joint of the vehicle with the automatic transmission that does not reflect the current execution control amount in the integral term of the next control amount is engaged. It is a force control device.

The invention of claim 3 of the present invention combines the determined P with the configuration of the invention of claim 1 or 2.
When the ID feedback control amount is equal to or more than a predetermined value, the control of the adjusting means is executed with the predetermined value, and the PID feedback control amount is determined based on the integral value used to determine the PID feedback control amount in the previous control. Is a fastening force control device for a fluid joint of a vehicle with an automatic transmission.

[0014]

According to the first aspect of the present invention, the adjusting means adjusts the engagement state of the lock-up clutch, and the operating state detecting means detects the operating state of the vehicle. The above-mentioned slip amount detecting means detects a value relating to a slip amount (actual slip amount) between the input element and the output element, and the control means based on the detection results of the operating state detecting means and the slip amount detecting means. The above-mentioned control means is controlled, and the above-mentioned control means determines a target slip amount of the lock-up clutch based on a driving state of the vehicle, and a difference (error) between the determined target slip amount and the detected actual slip amount. And the adjusting means sets P based on the differential value and the integral value so that the actual slip amount approaches the target slip amount.
The ID feedback control amount is determined.

[0015] The above control means determines the determined PID.
The control of the adjusting means is executed based on the feedback control amount. When the determined PID feedback control amount is equal to or more than a predetermined value (when the PID feedback control amount exceeds the predetermined value), the control of the adjusting means is executed with this predetermined value. However, the current execution control amount is not reflected on the integral term of the next control amount.

As a result, when the PID feedback control amount exceeds a predetermined value due to a failure of the control device or the like, the control using the above-mentioned predetermined value and the integral value of the error should not be reflected in the control. Can prevent the stability of the PID feedback control from being impaired by both of them, and have the effect of stabilizing the control.

According to the invention described in claim 2 of the present invention,
In addition to the effect of the first aspect of the present invention, in the reverse driving state in the above-mentioned slip control region, the above-mentioned control means keeps the slip amount smaller than the target slip amount at a predetermined fastening force while determining. When the PID feedback control amount obtained is equal to or larger than a predetermined value, the control of the adjusting means is executed with the predetermined value, and the current execution control amount is not reflected on the integral term of the next control amount. There is an effect that the control amount can be stabilized without reflecting the abnormal control amount under the driving state in the next PID feedback control amount.

According to the third aspect of the present invention,
In addition to the effect of the invention described in claim 1 or 2, when the determined PID feedback control amount is equal to or more than a predetermined value, the control of the adjusting means is executed with the predetermined value, and the PID feedback control amount is determined in the previous control. Since the PID feedback control amount is determined based on the integral value used for the determination, that is, the integral term in the previous control is held, there is an effect that the control can be stabilized.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to the drawings. The drawings show a fastening force control device for a fluid joint of a vehicle with an automatic transmission. First, an overall configuration of the vehicle will be described with reference to FIG.

In FIG. 1, this vehicle has left and right front wheels 1 and 2 as driven wheels, left and right rear wheels 3 and 4 as driving wheels, and the output torque of an engine 5 is transmitted from an automatic transmission 6 to a propeller shaft 7. The power is transmitted to the left and right rear wheels 3 and 4 via the driving device 8 and the left and right drive shafts 9 and 10.

The wheels 1 to 4 have these wheels 1 to 4 respectively.
4 and a caliper 12 for receiving the supply of a braking pressure (brake pressure) and braking the rotation of the disks 11. On the other hand, a CPU 40 is provided as a control unit that outputs a shift signal to the shift unit 20 of the automatic transmission 6 based on the current traveling speed of the vehicle.

The above-described CPU 40 has a ROM 17 (see FIG. 6) for storing programs and a RAM 18 (see FIG. 6) for storing data and maps. The RAM 18 stores a map M1 as shown in FIG. doing. Next, FIG.
The system configuration of the automatic transmission 6 will be described with reference to the AT skeleton shown in FIG.

As shown in FIG. 3, the automatic transmission 6 is provided with a torque converter 21 as a fluid coupling and a multi-stage transmission gear mechanism 22. Torque converter 2
1 includes a pump 25 (input element) mounted in a case 24 connected to the engine output shaft 23 and rotating with the engine output shaft 23 to discharge hydraulic oil.
Turbine 26 (output element) that is arranged to face the cylinder and is rotationally driven by hydraulic oil discharged from pump 25
And a stator 27 disposed between the pump 25 and the turbine 26 to regulate the flow of hydraulic oil between the pump and the turbine.
Are provided.

The stator 27 includes a one-way clutch 28
Through the transmission case 29. And
The rotation of the turbine 26 is controlled by a pipe-shaped turbine shaft 30.
Through the transmission gear mechanism 22. Further, the torque converter 21 is provided with a lock-up clutch 31 for directly connecting the engine output shaft 23 and the turbine shaft 30 (including a slip state) in accordance with an operation state.

The engine output shaft 23 is connected to a shaft 32 penetrating through a hollow portion of the turbine shaft 30, and the shaft 32 drives an oil pump 33 to rotate. The transmission gear mechanism 22 includes:
A planetary gear system 34 is provided. The planetary gear system 34 includes a turbine shaft 30.
A small sun gear 35 that is loosely fitted on the turbine shaft 3 at the rear (left side in FIG. 2) of the small sun gear 35.
0 and a plurality of short pinion gears 37 (1) meshing with the large sun gear 36 and the small sun gear 35.
A long pinion gear 38 whose front portion (right side in FIG. 2) meshes with the short pinion gear 37 and whose rear portion meshes with the large sun gear 36, a carrier 39 rotatably supporting the short pinion gear 37 and the long pinion gear 38, A ring gear 41 that meshes with the long pinion gear 38 is provided. Here, the ring gear 41 is connected to the output gear 42.

Various frictional engagement elements are provided for switching the power transmission path in the planetary gear system 34, that is, for switching the gear ratio (gear stage) or forward / reverse travel. Specifically, a forward clutch 43 and a first one-way clutch 44 are interposed between the turbine shaft 30 and the small sun gear 35 in series, and a coast clutch 45 (formally referred to as a coasting clutch; These are simply abbreviated as coast clutches) and are provided in parallel with both clutches 43 and 44.

A brake drum 46 connected to the large sun gear 36 is provided radially outward of the coast clutch 45.
A 2-4 brake 48 including a brake band 47 wound around the brake drum 46 is provided. Behind the 2-4 brake 48, the brake drum 46 (large sun gear 36) and the turbine shaft 3
A reverse clutch 49 for turning ON / OFF the power transmission between 0 and 0 is provided. Further, a low reverse brake 50 is provided between the carrier 39 and the transmission case 29.
And a second one-way clutch 51 are interposed in parallel.
Four clutches 52 are provided.

In such a transmission gear mechanism 22,
Clutches 43, 45, 49, 52 and brakes 48,
By switching 50 ON and OFF patterns,
The power transmission path in the planetary gear system 34 is switched to obtain four forward speeds and one reverse speed. Then, during driving, the optimum gear position is automatically set according to the range selected by the selection operation and the driving state of the vehicle.

FIG. 5 shows the relationship between each shift speed and the operating states of the clutches 43, 45, 49, 52 brakes 48, 50 and one-way clutches 44, 51 corresponding to the shift speeds. Next, a control configuration of the lock-up clutch 31 will be described with reference to FIG.

As shown in FIG. 4, the lock-up clutch 31 is provided between the converter cover 53 connected to the engine output shaft 23 and the turbine 26 when viewed in the axial direction of the turbine shaft 30 (the left-right direction in FIG. 1). A torsion damper 54 and a damper piston 55 that are arranged between the turbine shaft 30 and rotate integrally with the turbine shaft 30, and a friction plate (not shown) attached to the converter cover 53 at a position facing the damper piston 55. I have.

The damper piston 55 divides the space formed in the converter cover 53 into a rear chamber 56 located on the turbine 26 side and a front chamber 57 located on the converter cover 53 side. Here, the hydraulic pressure in the rear chamber 56 is an operating pressure in the lock-up strengthening direction acting in the direction of pressing the damper piston 55 against the friction plate, and the hydraulic pressure in the front chamber 57 is a direction for separating the damper piston 55 from the friction plate. Operating pressure in the lock-up release direction.

The damper piston 55 is connected to the rear chamber 5
6. Friction engagement with the friction plate or release from the friction plate with a fastening force corresponding to the hydraulic pressure difference between the front chambers 57. That is, the lock-up clutch 31 is completely disengaged and turned off in accordance with the oil pressure difference between the two chambers 56.57, and the rotation of the engine output shaft 23 is transmitted to the turbine shaft 30 via the pump or the working oil in the turbine 26. A lock-up mode in which the lock-up clutch 31 is completely engaged (without slipping) and the rotation of the engine output shaft 23 is directly transmitted to the turbine shaft 30; The piston 55 is brought into a semi-fastened state (slip state) in which the piston 55 slides and engages with the friction plate, and the rotation of the engine output shaft 23 is transmitted to the turbine shaft 30 via the hydraulic oil and also through the lock-up clutch 31. Thus, three types of transmission modes, that is, slip modes transmitted to the turbine shaft 30 are obtained.

A hydraulic circuit 58 is provided for switching the transmission mode of the lock-up clutch 31 and controlling the engagement force in the slip state. This hydraulic circuit 58
A shift valve 59 for switching the hydraulic pressure supply path, a control valve (lock-up valve) 60 for regulating the hydraulic pressure supplied to the front chamber 57 via the shift valve 59, and ON / OFF control of the first pilot pressure. A solenoid valve 61 that controls the duty of the second pilot pressure, and a CPU 40 that controls the solenoid valves 61 and 62 are provided.

The hydraulic circuit 58 includes a torque converter line 63 (hereinafter simply referred to as a torque converter line) into which a line pressure output from a pressure regulator valve (not shown) is introduced, and a first pilot pressure supply line. 1
A pilot line 64, a second pilot line 65 for supplying a second pilot pressure, a line 66 for supplying a constant pressure to the shift valve 59, a line 67 connecting the port 59R of the shift valve 59 and the rear chamber 56, A line 68 connecting the port 59F of the shift valve 59 and the front chamber 57 is provided.

The torque converter line 63 has two lines 69,
70, and one line 69 is connected to the shift valve 59.
The other line 70 is connected to the port 60A of the control valve 60. The port 60F of the control valve 60 is connected to the port 59B of the shift valve 59 via a line 71. The port 59C of the shift valve 59 is connected to a line 73 leading to the oil cooler 72.

The first pilot line 64 is branched into two lines 74 and 75. One line 74 is connected to the port 59D of the shift valve 59, and the other line 75
Is connected to the port 60B of the control valve 60. And the drain line 7 branched from the line 74
A solenoid valve 61 is provided in 5D. Here, the drain line 75D is closed when the solenoid valve 61 is in the OFF state, and is drained when the solenoid valve 61 is in the ON state.

The second pilot line 65 is branched into two lines 76 and 77, one of which is connected to the port 59E of the shift valve 59 and the other of which 77
Is connected to the port 60C of the control valve 60. A duty solenoid valve 62 is provided on a drain line 78 branched from the second pilot line 65. Duty solenoid valve 62 is OF
The drain line 78 is closed in the F state, and is drained in the ON state. In the intermediate region, a second pilot pressure is formed in the second pilot line 65 according to the duty ratio, and the second pilot pressure decreases as the duty ratio increases.

In the shift valve 59, the operation of the two spools according to the pilot pressure causes the port 59 to operate.
Switching of the communication state between R and the port 59A or the port 59C and switching of the communication state between the port 59F and the port 59B or the drain port are performed. In the control valve 60, the port 60F and the port 60F are operated by the operation of the spool according to the pilot pressure.
Switching of the communication state between A and the drain port is performed. Reference numeral 79 denotes a line for guiding hydraulic oil in the torque converter 21 to the oil cooler 72 via the check valve 80.

The switching between the three transmission modes of the lock-up clutch 31 (converter mode, lock-up mode, slip mode) is performed by the CPU 40 in accordance with the operating state. Specifically, it is executed based on the map M1 shown in FIG.

Hereinafter, the hydraulic circuit 5 in each transmission mode will be described.
8 and the operation of the lock-up clutch 31 will be abbreviated. Converter mode In this converter mode, the solenoid valve 61
FF is performed, and the duty ratio of the duty solenoid valve 62 is set to 0%. Thereby, both spools of the shift valve 59 are disposed on the left side in the positional relationship in FIG. 4 (FIG. 4 shows this state). At this time, the port 59 </ b> R communicates with the port 59 </ b> C, and the hydraulic pressure in the rear chamber 56 is changed via the line 67 and the line 73 to the oil cooler 72.
Will be released. On the other hand, port 59F is port 59B
The hydraulic pressure guided from the torque converter line 63 to the line 71 via the control valve 60 is transmitted to the front chamber 57.
Supplied to Therefore, the rear room 56 is connected to the front room 5
7 and the lock-up clutch 31
FF (released) and enters the converter state.

Lock-up mode In this lock-up mode, the solenoid valve 61 is turned on and the duty ratio of the duty solenoid valve 62 is set to 100%. Thereby, both spools of the shift valve 59 are disposed on the right side in the positional relationship in FIG. At this time, the port 59R communicates with the port 59A, and the hydraulic pressure of the torque converter line 63 is supplied into the rear chamber 56 via the line 69 and the line 67. On the other hand, the port 59F communicates with the drain port, and the hydraulic pressure in the front chamber 57 is released. Therefore, the pressure difference between the rear chamber 56 and the front chamber 57 becomes substantially equal to the line pressure, the lock-up clutch 31 is completely turned on (engaged), and no slip occurs.

Slip mode In this slip mode, the solenoid valve 61 is turned on.
Is done. The duty ratio of the duty solenoid valve 62 is set to a value corresponding to the deviation of the input / output rotation speed difference (slip amount) from the target value in a range of 20% or more. 4, the spool on the right side of the shift valve 59 is arranged on the right side, while the spool on the left side of the shift valve 59 is arranged on the left side in the positional relationship in FIG. At this time, the port 59R communicates with the port 59A, and the operating oil pressure is supplied into the rear chamber 56. On the other hand,
The port 59F communicates with the port 59B and the front room 57
The working hydraulic pressure is also supplied. Here, the hydraulic pressure supplied to the front chamber 57 is controlled by the duty solenoid valve 6.
It is controlled according to the duty ratio of 2. Therefore, the pressure difference between the rear chamber 56 and the front chamber 57 is controlled according to the duty ratio, and the engagement force of the lock-up clutch 31 is controlled accordingly.

In the slip mode, slip control is performed such that the engagement force of the lock-up clutch 31 is feedback-controlled according to the deviation of the input / output rotational speed difference from the target value.

FIG. 6 shows a control circuit of the fastening force control device for the fluid connection. The CPU 40 controls the engine speed Ne from the distributor 13, the turbine speed Nt from the turbine speed sensor 14, and the throttle opening TVO from the throttle sensor 15. , The duty solenoid valve 6 according to a program stored in the ROM 17 based on various necessary input signals such as the vehicle speed V from the vehicle speed sensor 16.
2, and the RAM 18 stores the map M1 shown in FIG. 2 and other necessary data.

The map M1 stored in the above-mentioned RAM 18
(See FIG. 2), the up-shift line and the down-shift line are set by taking the vehicle speed V on the horizontal axis and the throttle opening TVO on the vertical axis, and
(Fluid joint) pump 25 (input element) and turbine 2
6 (output element) (a lock-up ON area; see the right side of the imaginary line α in FIG. 2); and an area in which the pump 25 and the turbine 26 are completely opened (a lock-up OFF area). (Refer to the left side of the virtual line β in FIG. 2)
And a region SE in which the pump 25 and the turbine 26 are relatively rotatable relative to each other (refer to a hatched portion for a region in which slip control is executed).

That is, the above-mentioned map M1 serves as both a shift map and a lock-up clutch control map in which lock-up clutch engagement force control characteristics are set. Also,
The above-mentioned CPU 40 is a driving state detecting means for detecting the driving state of the vehicle (first step S in the flowchart shown in FIG.
1), a slip amount detecting means for detecting the actual slip amount RS between the pump 25 as an input element and the turbine 26 as an output element (see the fifth step S5 in the flowchart shown in FIG. 7), and Adjusting means (refer to hydraulic circuit 58 including duty solenoid valve 62) based on the detection results of operating state detecting means (refer to first step S1) and slip amount detecting means (refer to fifth step S5)
(CPU 40 itself) that controls the target slip amount (see FIG. 8) of the lock-up clutch 31 based on the driving state of the vehicle, and determines the relationship between the determined target slip amount and the detected actual slip amount RS. Control amount determining means (see the flowchart shown in FIG. 7) for determining a PID feedback control amount (see function f) of the duty solenoid valve 62 based on the difference and its differential value and integral value so that the actual slip amount approaches the target slip amount. 14th step).

Then, the CPU 40 determines that the determined P
The control of the duty solenoid valve 62 is executed based on the ID feedback control amount (see step S21), and when the determined control amount of the PID feedback control is equal to or more than a predetermined value, that is, the upper limit value Ku shown in FIG.
In the above cases and when the value is equal to or less than the lower limit value Kd, the control of the duty solenoid valve 62 is executed with these predetermined values (the upper limit value Ku and the lower limit value Kd), and the current execution control amount D is changed to the next control amount integration term (I Section).

When the CPU 40 is in the reverse driving state in the slip control area SE in the map M1 shown in FIG. 2, the CPU 40 maintains the predetermined fastening force with the slip amount smaller than the target slip amount (see the twelfth step S12). On the other hand, the control of the execution control amount (see the sixteenth step S16 and the eighteenth step S18) and the update control of the integral term (see the nineteenth step S19) are performed.

Further, the above-mentioned regulation for updating the integral term is configured to hold the integral term in the previous control (see the nineteenth step). The operation of the thus-configured control device for the fluid joint of the vehicle with the automatic transmission will be described in detail below with reference to the flowchart shown in FIG. The contents of the symbols used in the following description are as follows.

Ne: engine speed Nt: turbine speed TVO: throttle opening V: vehicle speed A: predetermined value of duty ratio B: predetermined value of slip amount C: setting value of throttle opening ( for example the fully closed) and D ...... slip duty control amount (so-called duty ratio) D ₀ ...... previous error RO ₁ ... target slip amount RO ₂ ... TVO zero fully closed during normal with respect to the duty ratio es ...... target slip amount F (i): feedback determination flag (current), (feedback control execution flag) F (i-1): previous feedback determination flag Ku: upper limit of duty ratio Kd: lower limit of duty ratio RS: Actual slip amount (RS = Ne−Nt) f: Function es is an integrated value of error es is error a, b, c, b ′, c ′ are constants es [i] −es [ i-1] is a change in error a × ies is an integral term b ′ × es is a proportional term c ′ × es [i-1] is a differential term In the first step S1, the CPU 40 determines the engine speed Ne from the distributor 13 , The turbine speed Nt from the turbine speed sensor 14 and the throttle sensor 1
5 and the vehicle speed V from the vehicle speed sensor 16 are detected. Next, in a second step S2, the CPU 40 determines whether or not the slip control area SE is present on the basis of the detected vehicle speed V and the throttle opening TVO based on the map M1 in FIG. 2. If YES, the process skips to the fifth step S5. On the other hand, when the determination is NO, the next third
Move to step S3.

In the third step S3, the CPU 40 determines whether or not the current vehicle driving state is in the lock-up ON area based on the map M1 in FIG.
While returning to step S1, when the determination is YES, the process proceeds to the next fourth step S4.

In the fourth step S4, the CPU 40 drives the duty solenoid valve 62 with the duty ratio D set to 100% to completely engage the lock-up clutch 31. On the other hand, in the above-described fifth step S5, the CPU 40
Calculates the actual slip amount RS. That is, the actual slip amount RS is obtained by subtracting the turbine speed Nt from the engine speed Ne.

Next in the sixth step S6, CPU 40 is the absolute value of the difference es between the actual slip amount RS and the target slip amount RO ₁ is determined whether larger or than a predetermined value B, the following first to determination YES The process shifts to the seventh step S7, whereas if the determination is NO, the process shifts to another eighth step S8. In the above-described seventh step S7, in response to the difference es being larger than the predetermined value B, the CPU 40 sets the previous duty ratio D ₀ to a predetermined value in order to execute control (feedforward control) not based on the difference es. The current duty ratio D is calculated by taking the value A into consideration, and the duty solenoid valve 62 is driven at this duty ratio D. This prevents occurrence of hunting due to feedback control when the difference es is smaller than the predetermined value B.

On the other hand, in the above-mentioned eighth step S8, the CPU
40 sets the present feedback determination flag F (i) to "1", and in the next ninth step S9, the CPU 40 determines whether or not the previous feedback determination flag F (i-1) is "0". When F (i-1) = 0, the process proceeds to the next tenth step S10, and when F (i-1) = 1, another first step S10 is performed.
Skip to step S11.

In the above-described tenth step S10, the CPU 4
0 determines the integral value ies of the error es to be zero, and
In step S11, the CPU 40 sets the throttle opening TVO
Is less than or equal to a set value C (for example, fully closed),
If <C, the process proceeds to the next twelfth step S12,
When O> C, the process proceeds to another thirteenth step S13.

[0056] In a thirteenth step S13 described above, in response to a normal driving state in which the drive force is transmitted from the engine 5 side to the driven wheels 3 and 4 side, CPU 48 is error es the equation of Ne-Nt-RO ₁ Ask for. On the other hand, in the above twelfth step S12, C corresponds to the reverse driving state (engine braking state) in which the engine 5 is rotated from the driving wheels 3 and 4 side.
PU40 determine the error es by the equation of Ne-Nt-RO _2. Next, in a fourteenth step S14, the CPU 40
The function f as the D feedback control amount is expressed by the following [Equation 1].
The function f is set to the duty ratio D.

[0057]

(Equation 1)

Next, in a fifteenth step S15, the CPU 40
Determines whether or not the determined duty ratio D is equal to or greater than the upper limit value Ku shown in FIG. 8, that is, determines whether or not the duty ratio D is in a state indicated by a virtual line u in FIG. K
When u is determined, the process proceeds to the next sixteenth step S16. On the other hand, when the determination is NO (when D <Ku), the process proceeds to another seventeenth step S17.

In the above-described sixteenth step S16, the CPU 4
0 corresponds to the determined control amount of the PID feedback control (refer to the function f) being equal to or more than the upper limit Ku as the predetermined value, and after setting the upper limit Ku to the duty ratio D, returns to the nineteenth step S19. Transition.

On the other hand, in the above-mentioned seventeenth step S17, C
The PU 40 determines whether or not the duty ratio D determined in the fourteenth step S14 is equal to or less than the lower limit value Kd illustrated in FIG. 8, that is, determines whether the duty ratio D is in a state indicated by a virtual line d in FIG. When the determination is YES (D ≦ Kd), the next first
On the other hand, when the duty ratio D is between the upper and lower limit values Ku and Kd (when NO is determined), the process proceeds to another twentieth step S20.

In the above-mentioned eighteenth step S18, the CPU 4
0 corresponds to both the determined control values of the PID feedback control (see the function f) being equal to or less than the lower limit value Kd as a predetermined value. After setting the lower limit value Kd to the duty ratio D, the process proceeds to the nineteenth step S19. I do. In the above-described nineteenth step S19, in response to the determined control amount of the PID feedback control (refer to the function f) being equal to or more than the upper limit Ku or equal to or less than the lower limit Kd, the integral term is updated (update prohibited). The CPU 40 sets the previous integral value ies (i-1) as the current integral value ies for the purpose. That is, the integral term in the previous control is held as it is.

On the other hand, in the twentieth step S20, corresponding to the fact that the determined control amount of the PID feedback control (see the function f) is between the upper limit value Ku and the lower limit value Kd,
The CPU 40 adds the current error e to the previous integral value ies (i-1).
s is added, and the integrated value ies of the error is updated. Next, in a twenty-first step S21, the CPU 40 controls the drive of the duty solenoid valve 62 at the duty ratio D obtained in each of the above steps, and causes the lock-up clutch 31 to slip via the hydraulic circuit 58 in accordance with the above-described duty ratio D. Control state.

In short, according to the fastening force control apparatus for a fluid coupling of a vehicle with an automatic transmission according to this embodiment, the adjusting means (see the hydraulic circuit 58 including the duty solenoid valve 62) engages the lock-up clutch 31. The state is adjusted, and the above-described driving state detecting means (refer to the first step S1) detects the driving state of the vehicle, and the slip amount detecting means (refer to the fifth step S5) is connected to the input element (refer to the pump 25). The control means (see CPU 40) detects a value relating to the slip amount (see actual slip amount RS) between the output element (see turbine 26) and the operating state detecting means (see first step S1). Fifth
Based on the detection result of step S5), the above-mentioned adjusting means is controlled. Further, the above-mentioned control means (see CPU 40) determines the target slip amount of the lock-up clutch 31 (see FIG. 8) based on the driving state of the vehicle. The PID of the adjusting means is determined based on the difference between the determined target slip amount and the detected actual slip amount RS (refer to the error es) and the differential value and the integral value thereof so that the actual slip amount approaches the target slip amount. Feedback control amount (14th step S1
4).

The control means (see CPU 40) executes the control of the adjusting means based on the determined PID feedback control amount. When the determined PID feedback control amount is equal to or more than a predetermined value (in this embodiment, the upper limit is set). When the value is equal to or more than the value Ku and when the value is equal to or less than the lower limit Kd, the control of the above-described adjusting means is executed at this predetermined value (see upper and lower limits Ku and Kd), and the current execution control amount (duty ratio D Is not reflected in the next integral term of the controlled variable (see Equation 1).

As a result, due to failure of the control device such as disconnection or sticking of the throttle sensor 15 and the like,
When the PID feedback control amount is a predetermined value (the upper and lower limit values Ku,
Kd), it is possible to prevent the stability of the PID feedback control from being impaired by both the control using the above-described predetermined value and the fact that the integrated value ies of the error is not reflected in the control. This has the effect of stabilizing the control.

[0066] Further, when the reverse drive state in the above-mentioned slip control region SE, the aforementioned control unit (see CPU 40) whereas slippage than the target slip amount RO ₁ is held to a small predetermined fastening force, execution control The amount (refer to the duty ratio D) is regulated (the card is played using Ku and Kd) and the integral term is regulated (see the nineteenth step S19). That is, when the determined PID feedback control amount is equal to or larger than the predetermined value, the control of the adjusting means is executed with the predetermined value, and the current execution control amount is not reflected on the integral term of the next control amount, so that the control becomes unstable. Therefore, there is an effect that the control can be stabilized without reflecting the abnormal control amount under the reverse driving state to the next PID feedback control amount.

Further, the above-mentioned control means (see CPU 40) determines the determined P in the reverse drive state where the control becomes unstable.
When the ID feedback control amount (see function f) is a predetermined value (K
u), the control of the adjusting means is executed with the predetermined value (see Ku), and the integral value i used for determining the PID feedback control amount in the previous control is determined.
Since the integral term in the previous control for determining the PID feedback control amount is held based on es (i-1), that is, the nineteenth step S19 in the flowchart shown in FIG.
(Previous integral value holding means) calculates the previous integral value ies (i-1)
Therefore, there is an effect that the control can be stabilized.

In the configuration of the present invention and the above-described embodiment, the fluid coupling of the present invention corresponds to the torque converter 21 of the embodiment, and similarly, the input element is the pump 25
The output element corresponds to the turbine 26, the adjusting means corresponds to the hydraulic circuit 58 including the duty solenoid valve 62, and the operating state detecting means corresponds to the first step S1 controlled by the CPU 40, and the slip amount The detection means corresponds to the fifth step S5, and the control means
0 itself, the PID feedback control amount is
The predetermined value of the control amount of the PID feedback control corresponds to the upper limit Ku and the lower limit Kd corresponding to the function f, and the lock-up clutch engagement force control characteristic corresponds to the characteristic set in the map M1 of FIG. The slip control area corresponds to the hatched area SE in the map M1 in FIG. 2, and the step of regulating the execution control amount corresponds to each of steps S16 and S18 in FIG. 7, and the update of the integral term is regulated. The step corresponds to the nineteenth step S19 in FIG. 7, and the step of holding the integral term in the previous control corresponds to the nineteenth step S19 in FIG. 7, but the present invention is limited to only the configuration of the above-described embodiment. It is not limited.

For example, it is needless to say that the control may be performed by using a slip ratio which is a ratio instead of the slip amount. In the present invention, the claims are not reflected.
Although an embodiment in which no reflection is performed is disclosed as a specific example of the description, it may be reflected at all so as not to adversely affect the next control. For example, about 10% may be reflected. Needless to say, it is good.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a vehicle including a fastening force control device for a fluid joint of a vehicle with an automatic transmission according to the present invention.

FIG. 2 is an explanatory diagram of a map.

FIG. 3 is a skeleton diagram of the automatic transmission.

FIG. 4 is a system diagram of a hydraulic circuit related to a lock-up clutch.

FIG. 5 is an explanatory diagram showing an operation for each range of a clutch and a brake.

FIG. 6 is a control circuit block diagram of the fastening force control device.

FIG. 7 is a flowchart showing engagement force control.

FIG. 8 is a time chart showing engagement force control.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 5 ... Engine 6 ... Automatic transmission 21 ... Torque converter (fluid coupling) 25 ... Pump (input element) 26 ... Turbine (output element) 31 ... Lockup clutch 40 ... CPU (control means) 58 ... Hydraulic circuit (adjustment means) 62: Duty solenoid valve (adjusting means) S1: Operating state detecting means S5: Slip amount detecting means

Claims (3)

[Claims] An automatic transmission is provided between an engine and an automatic transmission.
A lock-up clutch configured to be able to engage the input element and the output element of the fluid coupling directly or in a state where the two elements are relatively rotatable with each other; andadjustment means for adjusting an engagement state of the lock-up clutch. Operating state detecting means for detecting a driving state of the vehicle, slip amount detecting means for detecting a value relating to a slip amount between the input element and the output element, detection of the operating state detecting means and the slip amount detecting means Control means for controlling the adjusting means based on the result, the control means determines a target slip amount of the lock-up clutch based on the driving state of the vehicle, and the determined target slip amount and the detected actual slip amount The PID feedback control amount of the adjusting means is set so that the actual slip amount approaches the target slip amount on the basis of the difference between the differential slip amount and the differential value and the integral value. When the determined PID feedback control amount is equal to or greater than a predetermined value, the control of the adjusting means is executed with the predetermined value, and the control of the adjusting means is performed with the predetermined value. A fastening force control device for a fluid coupling of a vehicle with an automatic transmission that does not reflect the execution control amount in the integral term of the next control amount. 2. A region in which slip control is executed based on an operation state is set in the lock-up clutch engagement force control characteristic provided in the control means. While the slip amount is maintained at a predetermined fastening force smaller than the slip amount, the determined PID
2. The vehicle with an automatic transmission according to claim 1, wherein when the feedback control amount is equal to or more than a predetermined value, the control of the adjusting means is executed with the predetermined value, and the current execution control amount is not reflected on the integral term of the next control amount. Fluid coupling fastening force control device. 3. When the determined PID feedback control amount is equal to or more than a predetermined value, the control of the adjusting means is executed with the predetermined value, and the integrated value used to determine the PID feedback control amount in the previous control is calculated. Based on the PID
3. The fastening force control device for a fluid connection of a vehicle with an automatic transmission according to claim 1, wherein the feedback control amount is determined.