JP2001349419A - Transmission control device for automatic transmission - Google Patents

Abstract

(57) [Summary] The present invention relates to a shift control device for an automatic transmission, which can cope with variations in characteristics of the automatic transmission, aging, and the like by increasing the learning frequency of control parameters applied to neutral control. Accurate neutral control. SOLUTION: When a predetermined first operation state condition is satisfied when a shift range of an automatic transmission is in a travel range, a first control is performed to shift a friction element in a coupled state to a sliding engagement state. The operation is performed to achieve the neutral state, and at that time, the control parameter value applied to the second control is learned and corrected. Then, when a predetermined second operating state including at least the shift range being switched from the non-traveling range to the traveling range is established, the second control parameter value learned and corrected at the time of performing the first control is used. Is performed, and the friction element in the released state is operated to the sliding engagement state to achieve the neutral state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shift control device for an automatic transmission, and more particularly to a shift control device capable of executing a so-called idle neutral control.

[0002]

2. Description of the Related Art An automatic transmission provided in a vehicle such as an automobile is provided with a plurality of friction elements such as a hydraulic clutch and a hydraulic brake therein. Various controls such as achievement are enabled. In recent years, in a torque converter type automatic transmission, even when the shift position of the automatic transmission is in the D range (running range), when the vehicle is stopped (that is, in the idle state in a broad sense), Idle neutral control (hereinafter simply referred to as "neutral control"), which improves fuel economy and reduces vibration by approaching a neutral state such as when the shift position is in the N range or P range (non-travel range). Has been put to practical use.

[0003] The following two methods are currently in practical use as methods for implementing neutral control. One is that in a situation where a running vehicle is stopped in a running range, a friction element (forward clutch) coupled to achieve a low gear (for example, a first gear) is slipped to neutral. This is a method of performing control so as to approach the state (hereinafter, referred to as first neutral control). The other is that in a situation where a stopped vehicle is about to travel, when a shift change is made from the non-traveling range to the traveling range, the friction element (forward clutch) is not completely engaged immediately, but a predetermined release is performed. Until the condition (for example, the release of the foot brake operation) is satisfied, the friction element is slipped in a situation where the friction element can be immediately connected at any time, and a method of controlling so as to maintain a state close to a neutral state (hereinafter, referred to as a neutral state) , The second neutral control)
It is.

[0004]

Generally, in shift control of automatic transmissions, various control parameters applied to the shift control are constantly learned and corrected at the time of execution of the control, so that the characteristics of the automatic transmissions vary. The control accuracy is prevented from deteriorating due to the influence of the pressure and aging, and the shift feeling is improved. The same applies to each neutral control described above, and various control parameters are learned and corrected.

[0005] However, as a situation in which the neutral control is performed, for example, when the vehicle is stopped due to a signal waiting,
In such a case, many drivers leave the shift range in the drive range without switching to the non-drive range. For this reason, of the two neutral control methods described above, the frequency of the first neutral control is high, but the frequency of the second neutral control is relatively low, and the second neutral control is relatively low. For control, the learning frequency of the control parameters is not high.

When the learning frequency is low, since the control parameters do not converge and stabilize, it becomes difficult to perform accurate shift control in response to variations in characteristics of the automatic transmission and aging. For this reason, conventionally, when the second neutral control is performed, a clutch engagement shock occurs,
There is a possibility that troubles such as the inability to stably maintain the neutral state may occur.

SUMMARY OF THE INVENTION The present invention has been made in view of such a problem, and by increasing the frequency of learning control parameters applied to the neutral control, it is possible to accurately deal with variations in characteristics of the automatic transmission, aging, and the like. It is an object of the present invention to provide a shift control device for an automatic transmission that enables neutral control.

[0008]

In order to achieve the above-mentioned object, in the shift control apparatus for an automatic transmission according to the present invention, a first operating condition is satisfied when a shift range of the automatic transmission is in a running range. Then, the first control is performed to operate the friction element in the coupled state to the sliding engagement state to achieve the neutral state, and at that time, the control parameter value applied to the second control is learned and corrected. . Then, at least when the second operating state including the shift range of the automatic transmission is switched from the non-traveling range to the traveling range is established, the control parameter value learned and corrected at the time of performing the first control is used. And the second control is performed to operate the friction element in the released state to the sliding engagement state to achieve the neutral state.

Preferably, during the second control, a feedback control for feedback-correcting the engagement force of the friction element is performed, and a control parameter value output at the start of the feedback control is changed to a value of the first control. Perform learning correction at the time of implementation.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A shift control device for an automatic transmission according to an embodiment of the present invention will be described below with reference to the drawings. As shown in a schematic diagram showing the entire configuration of FIG. 1, the automatic transmission 1 is mounted on a vehicle (not shown) in a state where the automatic transmission 1 is coupled to an engine 2. The output shaft 2a of the engine 2 is connected to a transmission mechanism 4 via a torque converter (fluid coupling) 3, and the transmission mechanism 4 is connected to driving wheels of the vehicle via a differential gear (not shown).

The output shaft 2a of the engine 2 is connected to a pump impeller 3a of a torque converter (torque converter) 3. When the pump impeller 3a rotates with the rotation of the output shaft 2a, an automatic transmission transmission (ATF). The turbine runner (turbine) 3 b is driven to rotate via a fluid, and the rotation is transmitted to the transmission mechanism 4.

Although not described in detail, the transmission mechanism 4 is composed of a plurality of sets of planetary gear mechanisms and friction elements such as clutches and brakes that allow or restrict the operation of the components (sun gear, pinion gear, and ring gear). The clutch and brake engagement states are appropriately switched by an ATF supplied from a hydraulic pressure source (oil pump) to achieve a desired shift speed. Since the structure of the speed change mechanism 4 is generally widely known, components other than the forward clutch (U / D clutch) 7 that realizes the first speed by engaging are omitted from the drawings. I do.

On the other hand, an input / output device (not shown), storage devices (ROM, RAM, BURAM, etc.) for storing control programs and control maps, a central processing unit (CPU), a timer counter, and the like are provided in the vehicle interior. A / T-E provided
A CU (automatic transmission control unit, hereinafter simply referred to as ECU) 11 is installed, and various control signals are set based on information from various sensors described later, so that comprehensive control of the automatic transmission 1 is performed. Is being done.

[0014] the input side of the ECU11 is a turbine rotational speed detecting (input rotational speed of the other words, the forward clutch 7) the engine rotational speed sensor 12, the rotational speed of the turbine 3b N _T for detecting the rotational speed N _E of the engine 2 sensor 13, a vehicle speed sensor 14 for detecting a running speed (vehicle speed) V _S of the vehicle, the brake pressure switch 20 switches on / off on the basis of the pressure of the brake oil, the throttle opening theta _TH of the engine 2 (= accelerator operation amount ), An oil temperature sensor 17 for detecting the oil temperature T _{OIL of the} ATF, and a shift position (for example, N range, D range, P range, R range, etc.) selected by the driver. For example, various sensors such as a shift position sensor 18 and switches are connected. Instead of the brake pressure switch 20, a brake switch that is turned on when a brake pedal is depressed may be provided.

On the output side of the ECU 11, a number of solenoids and pressure regulating valves (pressure regulators) for controlling the switching of the operating oil from the oil pump to operate the clutch and brake engaging elements of the transmission mechanism 4 are provided. Control valve) is connected. Then, the ECU 11, sets the target gear position from a shift map (not shown) using the vehicle speed V _S detected by the throttle opening theta _TH and the vehicle speed sensor 14 detected by the throttle sensor 16, to achieve the target gear For this purpose, the solenoid and the pressure regulating valve are controlled to switch the engagement state of the engagement elements (clutch, brake and the like) of the transmission mechanism 4 to execute the transmission control. FIG. 1 shows only the solenoid 19 and the pressure regulating valve 21 for switching the engagement state of the forward clutch 7 among such a large number of solenoids and pressure regulating valves. Is omitted from the drawing.

The operation of the solenoid 19 is duty-controlled by the ECU 11, so that the supply state of the pilot pressure (control pressure) to the pressure regulating valve 21 is adjusted in accordance with the operation of the solenoid 19. Has become. Specifically, the pressure regulating valve 21 is controlled by the solenoid 19.
When the pilot pressure is supplied to the forward clutch 7, the spool 21a of the pressure regulating valve 21 moves to the left in the drawing.
, The line pressure is exhausted, and the engaging force of the forward clutch 7 decreases. Conversely, when the pilot pressure is discharged by the solenoid 19, the line pressure is supplied to the forward clutch 7 and the engagement force increases. Thus, by controlling the duty ratio of the solenoid 19, the engagement force of the forward clutch 7 can be adjusted. In the present embodiment, the engagement force of the forward clutch 7 is set to increase as the duty ratio of the solenoid 19 increases.

Next, the main parts of the present invention will be described.
The present shift control device is configured to enable accurate neutral control corresponding to variations in characteristics of the automatic transmission 1 and aging, etc., by increasing the learning frequency of control parameters applied to the neutral control. is there. Here, FIG. 2 is a functional block diagram focusing on the main functions of the present invention. As shown in the figure, a first neutral control unit (first control unit) 30 and a second neutral control unit (second control unit) are provided as functional elements in the ECU 11.
A learning correction unit 31 and a learning correction unit 32 are provided, and the above-described object is achieved by cooperation of these functional elements 30 to 32.

When all of the following start conditions (a1) to (a4) are satisfied (that is, when it is estimated that the vehicle has almost transitioned from the running state to the stopped state), the first neutral control unit 30 performs the connection. It has a function of controlling the duty ratio of the solenoid 19 for the forward clutch 7 in order to reduce the engagement force of the forward clutch 7 in the state and to achieve the neutral state by slidingly engaging the forward clutch 7. (A1) The shift position sensor 18 detects the travel range (D
Range) is detected. (A2) The brake pressure switch 20 is turned on (the brake pressure is equal to or higher than a predetermined value). (A3) The throttle sensor 16 has detected that the accelerator has not been operated (the throttle opening θ _TH is equal to or less than a predetermined amount). (A4) The vehicle speed V _S detected by the vehicle speed sensor 14 is less than a predetermined value.

Hereinafter, control contents of the neutral control (first neutral control) by the first neutral control section 30 will be described with reference to time charts shown in FIGS. 3 (a) to 3 (c). First, when all of the above-described neutral control start conditions (a1) to (a4) are satisfied (time point SS), the rush control of the neutral control is started, and FIG.
Forward clutch 7 in binding conditions the duty ratio D of 100% of the solenoid 19 as shown in (b) is reduced to just before the duty ratio D _N to S shape slipping. Thereafter, the duty ratio D is gradually reduced, and the forward clutch 7 is gradually operated to the disengagement side.

As a result, as shown in FIG. 3 (c), the hydraulic pressure of the forward clutch 7 gradually decreases, and the turbine 3b, which has been stopped and held in the connected state, begins to slip, and as shown in FIG. 3 (a). Thus, the turbine rotation speed _NT gradually increases. Then, when the turbine rotational speed N _T exceeds a predetermined slip determination value .DELTA.N _B (point SB1)
Then, the inrush control ends.

When the rush control is completed, next, the steady control is started. In this steady control, initially the turbine rotation speed N
_T of the rate of change dN _T / dt (hereinafter, simply referred to as dN _T) to feedback control of the duty ratio D so as to coincide with the target value. As the initial value of the duty ratio D of the steady state control start, added value is applied a predetermined value [Delta] D _B at the end of the duty ratio D which is gradually decreased in inrush control. Thereafter, the turbine rotational speed N _T is, when filled with relationship (A1) the following equation (as FB), in turn, the slip rotational speed (slip amount) of the turbine speed N _T and the engine rotational speed N _E The feedback control is performed so that N _S (= N _E −N _T ) becomes constant.

(N _E −N _T ) −N _Si <N _S12 (A1) In the above equation (A1), N _Si is a target slip rotation speed, and N _S12 is a threshold for switching a control target of feedback control. . Specifically, the first neutral control section 30 switches the control target change rate of the slip rotational speed N _S of the turbine speed change rate dN _T dN _S / dt (hereinafter, simply referred to as dN _S), the slip rotation Speeding rate d
A target value dN _Si is periodically set for N _S , and feedback control (PID control) is executed so that the slip rotation speed change rate dN _S becomes the target value dN _Si .

More specifically, the first neutral controller 30 calculates an output duty ratio D to be output to the solenoid 19 by using the following equation (B1). D = D _FB −ΔD _NE (B1) In the above equation (B1), D _FB is a feedback calculation term (PID correction term), and a deviation e (= dN) between the slip amount change rate dN _S and the target value dN _{Si. S−} dN _Si ). On the other hand, [Delta] D _NE is a correction term in accordance with the engine rotational speed N _E, the variation of the line pressure due to the fluctuation of the engine rotational speed N _E (i.e., variation in hydraulic pressure supplied to the forward clutch 7) in order to correct the It is added to the feedback operation term D _FB . The correction term ΔD _NE is given by (B
2) It is expressed by the equation. _{ΔD NE = (D S) SB1} - In _{(D S) n ... (B2} ) above (B2) equation, D _S is the initial value of the duty ratio is output when feedback control is started by the second neutral control section 31 described later , and the is set according to the engine rotational speed N _E and the oil temperature T _oIL. And
(D _S ) _SB1 is the engine speed N _E at time SB1
And the value of D _S corresponding to the oil temperature T _OIL, D _{S) n} is an engine value of the rotational speed N _E and the oil temperature T _OIL in the D _S corresponding to the present time (the latest). It will be described later in detail of the initial value D _S.

As described above, the first neutral control unit 30
It is the target of the feedback control to the boundary point FB switched from the turbine speed change rate dN _T to the slip rate of change dN _S, then release condition of the neutral control following continues the feedback control until satisfied. The conditions for canceling the neutral control are as follows (b1)-
(B3) is set, and if any one of them is established, the neutral control is canceled assuming that the driver has a will to start. (B1) When the brake pressure switch 20 is turned off (the brake pressure is less than a predetermined value). (B2) When the throttle sensor 16 detects an accelerator operation (throttle opening θ _TH is a predetermined value or more). (B3) The case where the traveling speed V _S detected by the vehicle speed sensor 14 has become equal to or higher than a predetermined value.

After the neutral control release condition is satisfied (at the point of time ES), the feedback control is released and the release control is started. That is, the predetermined duty ratio D _A
Duty ratio plus an increment [Delta] D _AF of (D _A + ΔD _AF) output for a short time t _AES1 to. This duty ratio (D _A + Δ
D _AF ) is output to reduce the play of the forward clutch 7 in the released state. Then, a predetermined time t
_AES1 outputs the initial duty ratio D _A When elapses, gradually operating the forward clutch 7 to the coupling side.

When the forward clutch 7 is operated to the coupling side, the turbine 3b, which has been rotating freely in the released state, is restrained by the forward clutch 7, and as shown in FIG. Turbine rotation speed _NT
Eventually it begins to drop. And the turbine rotation speed _NT
Satisfies the relationship of the following expression (C1) (time S
In B), starts the feedback control of the duty ratio D such that the change rate dN _T of the turbine rotational speed N _T is equal to the target change rate.

[0027] In _{(N E -N T) -N SP} > ΔN SB ... (C1) above (C1) equation, (N _E -N _T) represents the amount of slip of the torque converter 3, N _SP is the previous represents slippage quantity measured by the control period and (N _E -N _{T) OLD,} when representing the torque converter slip amount measured in the current control cycle and (N _E -N _{T) NEW,} the following (C2) formula (N
_E− N _T ) The value of _NEW . ΔN _SB is the slip rotation speed of the torque converter 3 that is used as a reference for determining the SB point.

[0028] _{(N E -N T) NEW>} (N E -N T) OLD ... (C2) target rate of change, the start of the first half of the feedback control is set to a relatively large value in order to increase the synchronization speed, When the turbine rotation speed _NT becomes equal to or lower than the predetermined speed _NTC (at time C
After D), the value is reset to a relatively small value in order to reduce the shock at the time of synchronization.

If a vehicle speed occurs during the release control, feedback control is performed so that the slip rotation speed change rate of the forward clutch 7 matches the target change rate. Here, the rotation speed change rate of the forward clutch 7 is
The difference ΔdN between the input-side rotation speed change rate of the transmission (that is, the turbine rotation speed change rate) dN _T and the change rate dN _T1 of the transmission rotation speed N _T1 immediately after the forward clutch 7.
It can be calculated as _{T (= dN T -dN T1)} . The rotation speed dN _T1 is the output rotation speed N of the transmission.
_{Using O} and the first gear ratio i ₁ , it can be expressed as N _T1 = i ₁ × N _O.

[0030] The above feedback control, the synchronous rotational speed at the time the turbine speed N _T and the first speed stage from time SB N _T1
And continues until the difference between the rotation speeds becomes smaller than or equal to a predetermined value (time point FF). After the end of the feedback control, the duty ratio D of the solenoid 19 is increased by a predetermined value ΔD _E , and after a lapse of a predetermined time (time SF), the duty ratio D is increased to 100%. Thus, the turbine rotational speed N _T is synchronized with the synchronous rotational speed N _T1 at the first speed stage, finally, completely equal to the oil pressure line pressure acting on the forward clutch 7 as shown in FIG. 3 (c) Is completed, and the first gear is achieved.

Next, the second neutral control section 31 will be described. When the following start conditions (c1) to (c4) are all satisfied, the second neutral control section 31 releases the forward clutch 7 in the disengaged state. It has a function of controlling the duty ratio of the solenoid 19 for the forward clutch 7 so as to achieve the neutral state by slipping engagement. (C1) The shift position sensor 18 has detected a shift change from the non-traveling range (N range) to the traveling range (D range). (C2) The brake pressure switch 20 is turned on (the brake pressure is equal to or more than a predetermined value). (C3) The throttle sensor 16 has detected that the accelerator has not been operated (the throttle opening θ _TH is equal to or less than a predetermined amount). (C4) The vehicle speed V _S detected by the vehicle speed sensor 14 is less than a predetermined value.

Hereinafter, the control contents of the neutral control (second neutral control) by the second neutral control unit 31 will be described with reference to time charts shown in FIGS. 4 (a) to 4 (c). First, when all of the above-described neutral control start conditions (c1) to (c4) are satisfied (time point SS), the rush control of the neutral control is started, and FIG.
As shown in (b), the duty ratio D of the solenoid 19 is increased from 0% to 100%. Since the forward clutch 7 has a clearance (play) between a clutch plate (not shown) and a clutch disk (not shown), it is necessary to reduce the play before coupling is performed.
In order to achieve a speed change in a short time, it is necessary to speed up the play to reduce the play. Therefore, the line pressure is supplied to the forward clutch 7 by setting the duty ratio to 100% at the start of the control (time point SS).

The play elimination of the forward clutch 7 is performed by a predetermined play elimination time t _F, elapses after the time point SS play elimination time t _F (point IF) reduces the duty ratio D to a predetermined duty ratio D _A , The forward clutch 7 is gradually operated from the disengagement side to the engagement side. When the forward clutch 7 is operated to the coupling side, the turbine 3b that has been rotating freely in the released state until now is restrained by the forward clutch 7, and as shown in FIG. _NT will soon begin to drop. Then, when the turbine rotation speed _NT satisfies the relationship of the above expression (C1) (time SB), it is determined that the forward clutch 7 is engaged, and the rush control ends.

When the rush control is completed, the steady control is started next. In this steady control, first outputs a predetermined duty ratio D _S less than the duty ratio D _A to the solenoid 19. Then, to start the feedback control of the predetermined duty ratio D _S as an initial value. Thus, for outputting a high duty ratio D _A from the initial value D _S without outputting the immediately initial value D _S after play elimination time t _F, the duty ratio during engagement of the forward clutch 7 D This is because if the value is too low, the decrease in the turbine rotational speed _NT will be small, and it may be difficult to determine the engagement start of the forward clutch 7 (the determination of the SB point).

[0035] In this neutral control performs feedback control so the turbine speed N _T and the engine rotational speed N _E and the slip rotational speed N _S of (= N _E -N _T) is constant. In this case, specifically, a target value is periodically set for a change rate dN _S / dt (hereinafter, simply referred to as dN _S ) of the slip rotation speed N _S , and the slip rotation speed change rate dN _S is set. The feedback control is performed so as to reach the target value. The feedback control is the same as the above-described conditions (b1) to (b3) for canceling the feedback control by the first neutral control 30, and continues until any of the conditions is satisfied (time ES). For the release control after the release condition is satisfied, the first neutral control unit 3
Since the content is the same as the release control by 0, the description is omitted here.

The second neutral control unit 3
Control parameters used in the 1, specifically, the initial value D _S at the feedback control start is an important parameter in the neutral control, the control characteristic is greatly influenced by the set value how. In other words, the forward clutch 7 when setting the initial value D _S is too large
Shock occurs engaged suddenly engaged, when setting the initial value D _S is too small, there is a fear that releases the forward clutch 7 engaged.

Therefore, in this transmission control device, the ECU 11
The functional element is a learning correction unit 32 of the optimum value of the initial value D _S at the feedback control start learning correction through actual control, are always to be able to perform an optimal shift control. In this shift control device, the learning correction of the initial value D _S by the learning correction section 32, the second neutral control section 3
1 during the neutral control by the first neutral control unit 30 as well as during the neutral control by the first neutral control unit 30.

More specifically, a steady control section [section B shown in FIG.
(1), B (2)], in the steady control section [section B shown in FIG. 4 (b)] by the second neutral controller 31, the following learning execution conditions (d1) to (d1) to ( _G1 ) are continuously performed for a predetermined time tG. d7)
When all the conditions are satisfied, the learning correction is executed. (D1) There is no change in ON / OFF of the air conditioner switch. (D2) the variation width of a predetermined engine rotational speed at the counting start time _{t G} (N _E) tGSTART compared to the engine rotational speed N _E is within a predetermined range. (D3) the difference between the actual slip rotational speed _{N S (= N E -N T} ) and the target slip rotational speed N _Si is within the predetermined range. ( _D4 ) The output duty ratio (D) at the start of counting for the predetermined time t _G The fluctuation range of the output duty ratio D is within a predetermined range as compared with _tGSTART . (D5) the engine rotational speed N _E is within a predetermined range. (D6) Oil temperature T of ATF detected by oil temperature sensor 17
_OIL is within a predetermined range. (D7) The traveling speed V _S detected by the vehicle speed sensor 14 is equal to or less than a predetermined value.

A description will now be given of the learning method of correcting the initial value D _S by the learning correction section 32. The initial value D _S is expressed as the sum of the basic value D _S0 as shown in (E1) formula learning value D _SL, learning correction unit 32 the engine rotational speed N every _E for the latter learned value D _SL The learning is performed for each oil temperature and oil temperature T _OIL . The initial value of the learning value D _SL in learning is not performed steps is set to 0. Also, the basic value D _S0 is set in advance according to the engine rotational speed N _E and the oil temperature oil temperature T _OIL.

D _S = D _S0 + D _SL (E1) The learning correction unit 32 first determines the learning value (the engine speed N _E and the oil temperature T _OIL at the end of the counting of the predetermined time t _G ). D _SL) the _END is read from the memory to calculate an initial value (D _{S) END [= D S0 + (D SL)} END ], as shown in the following (E2) equation, the average duty of the predetermined time t _G The difference ΔD _S from the rate (D) _AVE is calculated.

ΔD _S = (D) _AVE − (D _S ) _END (E2) After calculating the difference ΔD _S , the learning correction unit 32 calculates the difference ΔD _S.
Determined by referring to a map previously storing the correction amount [Delta] D _SL learned value D _SL in accordance with the. Here it is performed a weighting by setting stepwise the correction amount [Delta] D _SL as shown in FIG. 5 with respect to the difference [Delta] D _S. The upper limit value is set for the correction amount [Delta] D _SL. Then, learning correction unit 32, as shown in (E3) the following expression determined correction amount learned value of the [Delta] D _SL until the last (D _SL) current learning value by adding the _OLD (D _{SL) NEW} Is calculated.

(D _SL ) _NEW = (D _SL ) _OLD + ΔD _SL (E3) Thereby, the average duty ratio (D) of the predetermined time t _G is obtained.
_{If the} initial value (D _S ) _END is larger than _AVE , the learning value (D _SL ) _NEW is corrected to decrease, and conversely, the initial value (D _S ) _END is larger than the average duty ratio (D) _AVE. Is smaller, the learning value (D _SL ) _NEW is corrected to increase.
Calculated learned value (D _{SL) NEW} is stored in the storage area corresponding to the engine rotational speed N _E and the oil temperature T _OIL of the memory, used in the next control. The learning correction unit 32
As long as the learning start conditions (c1) to (c7) are satisfied, during the steady control section by the first neutral control section 30 and during the steady control section by the second neutral control section 31, Perform learning correction.

Since the shift control device for an automatic transmission according to one embodiment of the present invention is configured as described above, during operation of the vehicle, for example, a flowchart as shown in FIGS. Shift control is performed according to S130 or steps T10 to T100). First, when the vehicle stops while the shift range remains the traveling range (D range), the ECU 11 performs the shift control according to the flowchart shown in FIG. That is, in step S10, the neutral control start condition (a
It is determined whether 1) to (a3) are all satisfied. When all of the start conditions (a1) to (a3) are satisfied, the process proceeds to step S20. On the other hand, starting conditions (a1) to
If any one of (a3) is not established, the process proceeds to step S130, and the first speed is held as it is.

In step S20, the rush control of the neutral control is performed. After the rush control end starts the constant control, first, feedback control of the duty ratio D as the turbine speed change rate dN _T in step S30 coincides with the target value. Then, step S40
In initial value D _S learning start conditions of the learning value D _SL of (d1) ~
It is determined whether or not (d7) is all satisfied. When the learning start condition (d1) ~ (d7) is satisfied all, the process proceeds to step S50 performs a learning correction of the learning value D _SL, stored in a storage area corresponding to the engine rotational speed N _E and the oil temperature T _OIL I do. Then, after learning is completed, the process proceeds to step S60.
On the other hand, if any one of the learning start conditions (d1) to (d7) is not satisfied, the process proceeds to step S60 without performing learning.

In step S60, it is determined whether the neutral control release conditions (b1) to (b3) are satisfied. When none of the release conditions (b1) to (b3) is satisfied, the process proceeds to step S70, and when any one of the conditions is satisfied, the process proceeds to step S120. In step S70, FB
The point is determined, that is, it is determined whether or not the above-described equation (B1), which is the switching condition of the control target of the feedback control, is satisfied. Until the formula (B1) is satisfied in step S70, the processing of steps S30 to S70 is repeated,
When in step S70 (B1) equation is satisfied, it switches the control target of the feedback control proceeds to step S80 from the turbine speed change rate dN _T to the slip rotation speed variation rate dN _S.

In step S80, the duty ratio D is feedback-controlled so that the slip rotation speed change rate dN _S matches the target value. Then, the learning start conditions of the learning value D _SL of the initial value D _S in step S90 (d1) ~ (d
It is determined whether or not 7) is all satisfied. When the learning start condition (d1) ~ (d7) is satisfied all, the process proceeds to step S100 performs a learning correction of the learning value D _SL, stored in a storage area corresponding to the engine rotational speed N _E and the oil temperature T _OIL I do. Then, after learning ends, the process proceeds to step S110.
On the other hand, if any one of the learning start conditions (d1) to (d7) is not satisfied, the process proceeds to step S110 without performing learning.

In step S110, it is determined whether the neutral control release conditions (b1) to (b3) are satisfied. As long as none of the release conditions (b1) to (b3) are satisfied, the processing of steps S80 to S110 is repeated,
If any one of them is established, the process proceeds to step S120. Then, in step S120, the steady control is released and the release control is executed. Thus, the shift to the first speed is achieved.

On the other hand, when the shift is changed from the non-traveling range (N range) to the traveling range (D range) when the vehicle is stopped, the ECU 11 performs the shift control according to the flowchart shown in FIG. That is, the neutral control start conditions (c1) to (c) in step T10.
It is determined whether or not 3) is all satisfied. If all of the start conditions (c1) to (c3) are satisfied, step T
Go to 20. If any one of the start conditions (c1) to (c3) is not satisfied, the process proceeds to step T100,
The forward clutch 7 in the disengaged state is operated to the engaged state to shift to the first speed.

In step T20, the rush control of the neutral control is performed. Then, when the forward clutch 7 starts engaging, that is, when the relationship of the above-mentioned formula (C1) is established, the rush control is ended and step T
Proceeds to 30, reads the learned value D _SL of the initial value D _S from the memory area corresponding to the engine rotational speed N _E and the oil temperature T _OIL. In step T40, the initial value D _S obtained by adding the read learned value D _SL to the reference value D _S0 solenoid 1
9 and then start the steady control after step T50.

In step T50, the duty ratio D is feedback-controlled so that the slip rotation speed change rate dN _S matches the target value. Then, the learning start conditions of the learning value D _SL of the initial value D _S in step T60 (d1) ~ (d
It is determined whether or not 7) is all satisfied. When the learning start condition (d1) ~ (d7) is satisfied all, the process proceeds to step T70 performs learning correction of the learning value D _SL, stored in a storage area corresponding to the engine rotational speed N _E and the oil temperature T _OIL I do. After completion of the learning, the process proceeds to step T80. On the other hand, if any one of the learning start conditions (d1) to (d7) does not hold, step T is executed without performing learning.
Go to 80.

In step T80, it is determined whether the neutral control release conditions (b1) to (b3) are satisfied. While none of the cancellation conditions (b1) to (b3) is satisfied, the processing of steps T50 to T80 is repeated, and if any one of the conditions is satisfied, the process proceeds to step T90. Then, in step T90, the steady control is released and the release control is executed. Thus, the shift to the first speed is achieved.

[0052] I I performing the control as described above, the initial value D _S of the control parameter a is the feedback control start time associated with a second neutral control not only the second during the performance of the neutral control, the shift range Is also corrected during the execution of the first neutral control that is performed when the vehicle stops while the vehicle remains in the travel range (D range).

[0053] Thus, according to this shift control device, the initial value D _S has good convergence to be learned at a high frequency, precise shift corresponding to the variation of the optimum value between each individual of the automatic transmission 1 Control can be implemented. In particular, in the shift control device, the initial value D _S is a control parameter relating to the control of the forward clutch 7 by learning at a high frequency, it can cope with aging of the forward clutch 7, upon engagement of the forward clutch 7 There is also an advantage that the occurrence of a shock can be prevented and the neutral control can be performed without a sense of incongruity. Further, there is an advantage that the forward clutch 7 once engaged is not released, and the engine 2 is not blown up even when the accelerator is depressed to cancel the neutral control.

[0054] Further, in the shift control apparatus, even in the first in the feedback control of the neutral control, the initial value for the calculation of the correction term [Delta] D _NE for correcting the variation of the line pressure due to the fluctuation of the engine rotational speed N _E while using the D _S, because the good stability fast convergence of the initial value D _S as described above, it is possible to correct for variations in supply line pressure to the forward clutch 7, the hunting in the neutral control There is also the advantage that it can be prevented.

The embodiment of the shift control device for an automatic transmission according to the present invention has been described above. However, the present invention is not limited to the above-described embodiment, and is not limited to the scope of the present invention. Various modifications are possible. For example, in this embodiment, the initial value D of the duty ratio output at the start of the feedback control in the second neutral control
_{Although S} is learned and corrected, it is of course possible to learn and correct other control parameters.

Further, the present invention is widely applicable to automatic transmissions such as a continuously variable transmission that transmits the driving force of an engine via a fluid clutch (torque converter). In the case of a continuously variable transmission, the same effects as described above can be obtained by applying the present invention to engagement control of a forward clutch or a reverse brake that switches between forward and backward.

[0057]

As described above in detail, according to the transmission control apparatus for an automatic transmission of the present invention, the learning correction of the control parameter value applied to the control by the second control means is performed more frequently. The control parameter value can be learned at a high frequency by performing the control by one control means, so that the control parameter value can be quickly converged, and accurate shift control corresponding to the variation of the automatic transmission can be performed. It has the advantage that it can always be implemented.

In particular, feedback control for feedback-correcting the engaging force of the friction element is performed during the second control, and the control parameter value output at the start of the feedback control is learned and corrected at the time of the first control. In this case, there is an advantage that it is possible to cope with a temporal change of the friction element, to always secure an optimal engagement response, and to prevent a shock when the friction element is engaged.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an overall configuration of a shift control device for an automatic transmission as one embodiment of the present invention.

FIG. 2 is a functional block diagram focusing on main functions of a shift control device for an automatic transmission as one embodiment of the present invention.

FIG. 3 is a time chart showing control characteristics of a first neutral control according to a shift control device for an automatic transmission as one embodiment of the present invention, and FIG. 3 (a) shows a time change of a rotation speed of a turbine shaft. FIG. 4B is a diagram showing a control timing of a duty ratio of a solenoid, and FIG. 4C is a diagram showing a time change of a hydraulic pressure of a forward clutch.

FIG. 4 is a time chart showing a control characteristic of a second neutral control according to the shift control device of the automatic transmission as one embodiment of the present invention, and (a) shows a time change of a rotation speed of a turbine shaft. FIG. 4B is a diagram showing a control timing of a duty ratio of a solenoid, and FIG. 4C is a diagram showing a time change of a hydraulic pressure of a forward clutch.

5 is a diagram illustrating a method of setting the correction amount initial value D _S according to the speed change control apparatus for an automatic transmission according to an embodiment of the present invention.

FIG. 6 is a flowchart illustrating an operation of a shift control device for an automatic transmission according to an embodiment of the present invention.

FIG. 7 is a flowchart illustrating an operation of a shift control device for an automatic transmission according to an embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 automatic transmission 2 engine 7 forward clutch (friction element) 11 ECU 30 first neutral control unit (first control unit) 31 second neutral control unit (second control unit) 32 learning correction unit (learning correction unit)

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Katsutoshi Usuki 5-33-8 Shiba, Minato-ku, Tokyo Inside Mitsubishi Motors Corporation (72) Inventor Masato Shimadzu 5-33-8 Shiba, Minato-ku, Tokyo Mitsubishi F-term (reference) in Automotive Industry Co., Ltd. 3J552 MA02 MA12 NA01 NB01 PA47 PA54 RA20 RB02 RC13 SA18 TA01 TA11 VA32Z VA33Y VA48Z VA66W VB01Z VC01Z VC03W VD11W

Claims (2)

[Claims] When the first operating state condition is satisfied when the shift range of the automatic transmission is in the traveling range, the first friction element in the coupled state is operated to the sliding engagement state to achieve the first neutral state. When the second operation state including at least the shift range of the automatic transmission is switched from the non-travel range to the travel range is established, the friction element in the released state is operated to the sliding engagement state. A second control unit that achieves a neutral state by performing the control, and a learning correction unit that learns and corrects a control parameter value applied to the control by the second control unit when the control by the first control unit is performed. A shift control device for an automatic transmission. 2. The second control means includes feedback control means for performing feedback control of the engagement force of the friction element, and the learning correction means includes a control parameter value output at the start of feedback control by the feedback control means. 2. The shift control device for an automatic transmission according to claim 1, wherein learning correction is performed when control is performed by the first control means.