JP2001349421A - Gear shift control device of automatic transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To always allow control to a suitable engaging force even when a vehicle backs in relation to the gear shift control device of the automatic transmission, during a feedback control of an engaging force of friction elements based on an absolute value of output shaft rotation speed or an absolute value of input shaft rotation speed after release of neutral control. SOLUTION: It is discriminated whether or not the vehicle backs when the engaging force of the friction elements is feedback-controlled based on a parameter value related to the absolute value of at least the output shaft rotation speed of the automatic transmission to operate the friction elements to a connection state. When the backing of the vehicle is discriminated, a sign of the parameter value is inversed and the feedback control is performed based on the inversed parameter value.

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 a traveling range (D range), when the vehicle is stopped (that is, in an idle state in a broad sense), Idle neutral control (hereinafter simply referred to as "neutral control") has been put to practical use, in which fuel economy is improved and vibration is reduced by approaching a neutral state such as when the shift position is in the non-traveling range (N range). In the neutral control as described above, for example, the engagement force of the forward clutch is controlled by duty control of a solenoid valve that adjusts the supply state of the engagement hydraulic pressure to the forward clutch (friction element). By controlling the engagement force of the forward clutch in this manner, the slip amount of the forward clutch is controlled, and a state close to a neutral state can be realized even in the D range.

[0003]

By the way, when such a neutral control is executed, for example, FIG.
It is conceivable to perform control with the characteristics shown in FIG. Hereinafter, an example of the control method of the neutral control will be specifically described with reference to FIGS. 5A to 5C. First, the neutral control (in the figure, the neutral control is referred to as N control) is started. When the condition is satisfied (time point SS in FIG. 5B), the rush control of the neutral control is started. The conditions for starting neutral control are:
For example, a vehicle speed of 0 km / h, a foot brake operation, a throttle opening of 0%, and a lapse of a predetermined time from the achievement of the first speed are set. Neutral control is started based on the command.

In this case, as shown in FIG. 5B, the duty ratio D of the forward clutch solenoid is set to 10
From 0% to duty ratio D _N immediately before the forward clutch is slipping reduced stepwise. Thereafter, the duty ratio is gradually reduced at a constant gradient (dD _N ), and the forward clutch is gradually operated to the release side. As a result, as shown in FIG. 5C, the hydraulic pressure of the forward clutch decreases, and the turbine which has been stopped and held in the engaged state starts to rotate. When the turbine rotational speed N _T exceeds the slip determination value .DELTA.N _B shown in FIG. 5 (a), it starts the next stationary control terminates the inrush control [5
Time point SB1 of (b)]. In this steady control, first turbine rotation speed N _T of the rate of change dN _T / dt (hereinafter, simply dN
_The duty ratio D is feedback-controlled so that the duty ratio D matches the target value. As the initial value of the duty ratio D of the steady state control start to apply a value obtained by adding a predetermined value [Delta] D _B at the end of the duty ratio D which is gradually decreased in inrush control.

[0005] Then, the ratio of the turbine speed N _T and the engine speed N _E (N _T / N _E) is (point FB in the figure) to reach to a predetermined value, in turn, the turbine rotational speed N _T and the engine slip speed between the rotational speed _{N E N S (= N E} -
Feedback control is performed so that 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.} Is controlled so as to reach the target value. Thus, switching to the slip rotation speed variation rate dN _S a target boundary to the feedback control of the FB points shown in FIG from the turbine speed change rate dN _T, then, the above feedback to the release condition for neutral control is satisfied Continue control.

[0006] On the other hand, when the neutral control release condition is satisfied (at time ES in the figure), the predetermined duty ratio D _A becomes:
The duty ratio obtained by adding the predetermined duty ratio ΔD _AF is output for a short time t _AES1 , and the play of the forward clutch in the released state is _reduced . As the neutral control release condition, release of the foot brake operation, operation of the accelerator pedal, the vehicle speed has become a predetermined value or more, and the like are set. If any one of these release conditions is satisfied,
Release neutral control. Then, a predetermined time t _AES1
When but elapses, until the engagement start of the forward clutch is determined (up to the slip rotational speed of the torque converter exceeds a predetermined value) and outputs a predetermined duty ratio D _A.

[0007] engaging the start of the forward clutch is determined (time in FIG. SB), then performs feedback control so that the turbine speed change rate dN _T equal to the target change rate. Then, it is determined that the turbine rotational speed N _T is the forward clutch is synchronized and becomes equal to or less than the predetermined value (time point in FIG FF), after outputting by adding a predetermined duty ratio [Delta] D _E predetermined time, the duty rate of 100% To terminate the neutral control release control (time point SF in the figure).

When a vehicle speed is generated during the release control, the slip rotational speed change rate dN of the forward clutch is changed.
Feedback control is performed so that _SO matches the target change rate dN _Soi . Here the slip rotation speed variation rate of the forward clutch dN _SO, the input-side rotational speed variation rate of the transmission (i.e. the turbine rotation speed variation rate) and dN _T, the rotational speed variation rate of the forward clutch immediately after transmission dN _T1 / dt
(Hereinafter, simply referred to as dN _T1) the difference between (dN _T -dN
_T1 ). In addition, the rotation speed _NT1
Is the rotational speed N _O of the output shaft of the transmission and the gear ratio i _{1 of the} first speed.
Can be expressed as N _T1 = i ₁ × N _O, and the slip rotational speed change rate dN _SO of the forward clutch is expressed as dN
It can be expressed as _T -i ₁ × dN _O. Then, the slip rotation speed N _SO of the forward clutch (= _NT −i ₁ ×
The absolute value of N _O) is determined to have the forward clutch synchronization becomes below a predetermined value (time point in FIG FF), after outputting by adding a predetermined duty ratio [Delta] D _E predetermined time, the duty ratio to 100% Then, the neutral control release control is terminated (time point SF in the figure).

In the case where the neutral control is performed while the vehicle is stopped on a steep ascending road, if the neutral control is released by releasing the foot brake operation, the vehicle starts to retreat because the forward clutch is not engaged, and the vehicle retreats. The vehicle speed to the side occurs. At this time, the output shaft rotation speed N _O of the transmission becomes a negative value as shown by a solid line (actual i ₁ × N _O ) in FIG.

However, since the output shaft rotation speed sensor for detecting the output shaft rotation speed N _O cannot normally detect the rotation direction of the output shaft, it outputs the same signal both when moving forward and when moving backward. . For this reason, an electronic control unit (hereinafter, referred to as an ECU) that controls the automatic transmission includes a dash-dot line (ECU) in FIG.
Recognition i ₁ × N _O) speed of the forward side is mistaken to have occurred as indicated by the forward clutch slip rotation speed variation rate _{dN SO (= dN T -i 1} × dN O) actually smaller than ( (Negative value). Then, the target slip rotation speed change rate dN _Soi and the slip rotation speed change rate dN _SO
The deviation e (= dN _Soi −dN _SO ) is recognized as a value (positive value) larger than the actual value. The duty ratio to be output to the solenoid is set based on the deviation e (= dN _Soi −dN _SO ). When the deviation e is positive, the duty ratio is set to increase the slip rotation speed change rate as the absolute value increases. In order to lower the duty ratio, when the error e is mistakenly recognized as a value larger than the actual value as described above, the duty ratio needs to be increased but is not increased or conversely reduced.
Alternatively, the duty ratio is reduced more than necessary.

Further, if the vehicle continues to retreat, the turbine rotational speed _NT eventually becomes a negative value [FIG. 6 (a)].
After point B), the turbine rotation speed sensor for detecting the turbine rotation speed _NT cannot detect the rotation direction of the turbine similarly to the output shaft rotation speed sensor. For this reason,
As shown by the solid line (actual _NT ) in FIG. 6A, although the turbine rotational speed _NT is actually increasing in the retreating direction, the ECU returns as indicated by the dashed line (ECU recognition _NT ). to are mistaken assumed to rise in the forward direction, the fact despite positive value is a negative value a slip rotation speed variation rate _{dN SO (= dN T -i 1} × dN O) Recognized,
Further, the deviation e (= dN _Soi -dN _SO ) is recognized as a value smaller than the actual value. When the deviation e is erroneously recognized as a value smaller than the actual value, the duty ratio needs to be reduced but is not reduced or increased, or the duty ratio is increased more than necessary. .

As described above, according to the above-described control method, if the vehicle retreats after the neutral control is released, an appropriate duty ratio cannot be output to the solenoid. For this reason, there is a possibility that the engagement of the forward clutch may be delayed due to insufficient hydraulic pressure, or conversely, a shock may be generated due to the sudden engagement of the forward clutch due to excessive hydraulic pressure supply.

The above problem can be solved by making it possible to detect not only the magnitude of the rotational speed but also the rotational directions of the output shaft and the turbine. In such a solution, a new sensor is used. Since it is necessary to provide such a type, the cost is increased. Therefore, it is desired to solve the above-described problem by using only conventionally provided sensors without increasing the cost.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems. In the feedback control of the engagement force of the friction element based on the absolute value of the output shaft rotation speed or the input shaft rotation speed, which is performed after the neutral control is released, It is an object of the present invention to provide a shift control device for an automatic transmission, which can always control an appropriate engagement force even when the vehicle moves backward.

[0015]

In order to achieve the above-mentioned object, in the shift control device for an automatic transmission according to the present invention, the shift range of the automatic transmission is in a forward range, and a friction element to be coupled during running is controlled. When a predetermined condition is satisfied in the neutral state, the control of the friction element is performed by the feedback control means based on at least a parameter value related to an output shaft rotation speed of the automatic transmission in order to achieve a predetermined shift speed. The resultant force is feedback-controlled to operate the friction element in the coupled state. At this time, the reverse determination means determines that the vehicle is moving backward. When it is determined that the vehicle is moving backward, the sign of the parameter value is inverted by the inversion means, and the feedback control is performed based on the inverted parameter value. To do.

According to another aspect of the present invention, the predetermined condition is satisfied when the shift range of the automatic transmission is in the forward range and the friction element to be coupled during traveling is in the neutral state. When the condition is satisfied, in order to achieve a predetermined gear position, feedback control means performs feedback control of the engagement force of the friction element based on at least a parameter value related to the input shaft rotation speed of the automatic transmission to control the friction element. Operate to the combined state. At that time, the reverse determination means determines the backward movement of the vehicle and the reverse rotation determination means determines the reverse rotation of the input shaft, determines that the vehicle is moving backward, and further determines that the input shaft is reverse rotating. In some cases, the sign of the parameter value is inverted by the inversion means, and the feedback control is performed based on the inverted parameter value.

[0017]

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) is used. 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.

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 A sensor 13, an output shaft rotational speed sensor 15 for detecting the rotational speed N _O of the output shaft, a brake pressure switch 20 that switches on / off based on the pressure of brake oil, a throttle opening θ _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 (eg, N range, D range, P range, R range, etc.) selected by the driver. Shift position sensor 18 for detecting
And various sensors and switches are connected. In addition,
The engine rotation speed sensor 12, the turbine rotation speed sensor 13, and the output shaft rotation speed sensor 15 detect the magnitude (absolute value) of each rotation speed, and are not configured to detect the rotation direction.

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 uses a throttle opening degree θ _TH detected by the throttle sensor 16 and a vehicle speed V _S (calculated from the output shaft rotation speed N _O detected by the output shaft rotation speed sensor 15) from a shift map (not shown). A target gear is set, and the solenoid and the pressure regulating valve are controlled to achieve the target gear, thereby switching engagement states of engagement elements (clutches, brakes, and the like) of the transmission mechanism 4, and executing shift control. It has become. 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 duty of the solenoid 19 is controlled by the ECU 11 so that the supply state of the pilot pressure (control pressure) to the pressure regulating valve 21 is adjusted according to 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 neutral control will be briefly described. This neutral control is performed when a predetermined start condition is satisfied when the vehicle traveling in the D range stops.
The engagement force of the forward clutch 7 is reduced to control a state close to a neutral state, and the neutral control is executed by slidingly engaging the forward clutch 7 as a friction element.

The following release conditions (a1) to (a)
When either of the conditions 3) is satisfied, the neutral control is canceled assuming that the driver has a will to start. (A1) When the brake pressure switch 20 is turned off (the brake pressure is less than a predetermined value). (A2) When an accelerator operation (throttle opening θ _TH is equal to or more than a predetermined value) is detected by the throttle sensor 16. (A3) Running speed V _S calculated from output shaft rotation speed N _O
Is greater than a predetermined value.

Next, the main parts of the present invention will be described.
The present shift control device performs a release control that is performed after the neutral control is released, that is, a feedback control of an output duty ratio based on the output shaft rotation speed N _O and the turbine rotation speed N _T. It is configured to enable output of the rate.

FIG. 2 is a functional block diagram focusing on the functions of the main part of the present invention. As shown, the ECU 11
In the figure, a release control unit (feedback control unit) 30, a synchronization determination unit 31, a reverse determination unit (reverse determination unit) 32, a reverse rotation determination unit (reverse determination unit) 33, and a parameter sign inversion unit (determination unit) ) 34 are provided, and the above-mentioned object is achieved by cooperation of these functional elements 30 to 34.

The release control unit 30 determines whether the release condition (a
If any one of 1) to (a3) is satisfied (that is, if it is estimated that the driver has a will to start),
In order to release the neutral control and operate the forward clutch 7 from the slipping engagement state to the engagement state to achieve the shift to the first speed, the solenoid 19 for the forward clutch 7 is operated.
Has a function of controlling the duty ratio. Specifically, it is a functional element that controls (release control) the section from the time point ES to the time point FF in FIG. Since the control content of the release control is as described above, the description is omitted here.

The synchronization judging section 31 is a functional element for judging the synchronization of the forward clutch 7 in the above-mentioned release control, and makes a synchronization judgment as follows. First, when the output shaft rotation speed N _O is less than the detection limit value N _Omin , it is considered that the vehicle speed V _S has not occurred (that is, V _S = 0), and if the following equation (A1) holds once. , It is determined that the forward clutch 7 is synchronized. Note that the following equation (A
In 1), N0 is a predetermined rotation speed.

N _T <N 0 (A1) On the other hand, if the output shaft rotation speed N _O is _{equal to} or higher than the detection limit value N _Omin , it is considered that the vehicle speed V _S has occurred (ie, V _S ≠ 0), and If the equation (A2) is satisfied a predetermined number of times (or a predetermined time), it is determined that the forward clutch 7 is synchronized. In this way, the speed N _O is equal to the detection limit N
_{The reason why the} number of times of synchronization determination is increased (the synchronization determination time is made longer) as compared with the case of less than _Omin is to prevent erroneous determination when the vehicle is _moving backward as described later.

| N _T −i ₁ × N _O | <N1 (A2) Based on the above synchronization determination, the release control unit 30 ends the feedback control (time point FF) and the predetermined duty ratio ΔD
After adding and outputting _E for a predetermined time, the duty ratio is set to 100% and the release control is terminated. In the equation (A2), N1 is a predetermined rotation speed.

Next, the backward determining section 32 will be described.
The reverse determination unit 32 has a function of determining whether the vehicle is moving backward. Here, it is determined whether or not the output shaft rotation speed N _O detected by the output shaft rotation speed sensor 15 and the turbine rotation speed _NT detected by the turbine rotation speed sensor 13 satisfy the following expression (B1). are doing.

I₁× N_O-N_T> N2 (B1) When the above equation (B1) holds, the vehicle moves backward.
Is determined to be present. This is when the vehicle moves forward
If it is, the turbine rotation speed N _TIs synchronized
Rotation speed (i₁× N_OBecause it will never be smaller than
It is. Note that N2 is a predetermined rotation speed greater than 0
is there.

Next, the reverse rotation determining section 33 has a function of determining whether or not the turbine 3b is rotating in the reverse direction. The turbine rotational speed approaches the synchronous rotational speed as the forward clutch 7 is synchronized, but when the vehicle is moving backward, the synchronous rotational speed is actually a negative value. Therefore, when the synchronization of the forward clutch 7 proceeds, the turbine rotation speed also changes from a positive value to a negative value. However, as described above, the turbine rotational speed sensor 1
3 cannot detect the rotation direction of the turbine 3b, so that the turbine rotation speed _NT detected by the turbine rotation speed sensor 13 is always a positive value (absolute value). Therefore, when the actual turbine rotation speed changes from a positive value to a negative value, that is, when the turbine 3b rotates in the reverse direction, the detected turbine rotation speed _NT once decreases to zero and then increases again. Will show such a change.

Then, the reverse rotation determining unit 33 determines that the turbine 3b is activated when the turbine rotation speed _NT detected by the turbine rotation speed sensor 13 satisfies the following expression (C1) and then satisfies the following expression (C2). It is determined that it is rotating in the reverse direction. N _T <N3 (C1) N _T ≧ N4 (C2) N3 and N4 are predetermined rotation speeds, and are set to at least rotation speeds equal to or higher than the detection limit value of the turbine rotation speed sensor 13.

By the way, the relationship between the expressions (C1) and (C2) is established not only when the synchronization of the forward clutch 7 is advanced, but also when the driver depresses the accelerator after the expression (C1) is established. In this case, the forward clutch 7 slips and the turbine rotational speed _NT increases, and as a result, the relationship of the expression (C2) may be satisfied.

Therefore, the reverse rotation determining unit 33 determines whether the turbine 3b
Is determined to rotate in the reverse direction, it is determined whether or not the determination result is correct. Specifically, when the following equation (C3) is satisfied for a predetermined period of time, an erroneous determination is determined, and the determination result is canceled. N _T −i ₁ × N _O > N5 (C3) In the above equation (C3), N5 is a predetermined rotation speed (preferably set to be equal to N2 used for synchronization determination). When the determination result is canceled, the reverse rotation determining unit 33 determines again whether or not the turbine 3b is rotating in the reverse direction by using the above equations (C1) and (C2).

Next, the parameter sign inverting section 34 will be described. The parameter sign inverting section 34 performs feedback control based on the judgment result of the backward judgment section 32 and the judgment result of the reverse judgment section 33. , Ie, the turbine rotation speed change rate dN
_T and a function of inverting the sign (± sign) of the output shaft rotation speed change rate dN _O.

Specifically, first, when the reverse determining unit 32 determines that the vehicle is moving backward, the parameter sign inverting unit 34 inverts the sign of the output shaft rotational speed change rate dN _O. ing. Further, reverse rotation judging unit 33 when it is determined that the turbine 3b rotates in the reverse direction is adapted to invert the sign of the turbine speed change rate dN _T. Further, when the reverse rotation determining unit 33 determines that the reverse rotation judgment ahead is erroneous determination, it is again reversed the sign of the turbine speed change rate dN _T, so that the return to the original code.

Since the shift control device for an automatic transmission according to one embodiment of the present invention is configured as described above, when the neutral control is released, for example, a flowchart as shown in FIG. S210)
The feedback control is performed according to the following. In addition,
Here, a control method in the case where the vehicle moves backward after the neutral control is released will be described.

First, the conditions for starting the feedback control are satisfied.
Standing up (forward clutch 7 starts to engage
), The ECU 11 determines in step S10 the turbine rotational speed.
By the degree sensor 13 and the output shaft rotation speed sensor 15.
And detected turbine rotation speed N _T, Output shaft rotation speed N_O
Is read, and in step S20, the above equation (A2) is used.
It is determined whether the synchronization condition is satisfied. Synchronization condition satisfied
If the synchronization condition is satisfied, the process proceeds to step S30.
After adding 1 to the number I, the process proceeds to step S50. On the other hand,
If the term condition is not satisfied, the routine proceeds to step 40.
Resets the synchronization condition satisfaction count I to 0, and proceeds to step S
Go to 50. Note that the initial value of the number of times I that the synchronization condition is satisfied is 0.
Yes, set to 0 at the start of feedback control
I have.

In step S50, it is determined whether or not the flag F1 is 0. This flag F1 has an initial value of 0, and is set to 1 when the vehicle retreat is determined. Here, the flag F1 is determined since the vehicle retreat determination has not been made yet.
Is 0, and the process proceeds to step S60. Note that the flag F1
Is set to 1, the process proceeds to step S100.

In step S60, it is determined whether the vehicle is moving backward by using the above equation (B1). The above (B1)
If the expression is not satisfied, it is determined whether or not the synchronization condition satisfaction count I has reached the predetermined number of times I _max proceeds to step S200. If the synchronization condition satisfaction count I has reached the predetermined number of times I _max, the process proceeds to step S210, it determines that the forward clutch 7 are synchronized, and terminates the feedback control (point FF in Figure 5). On the other hand, if the synchronization condition satisfaction count I does not reach the predetermined number of times I _max, the step S190
The process proceeds, the duty ratio D is determined based on the turbine speed change rate dN _T and the output shaft rotation speed variation rate dN _O outputs to the solenoid 19, then returns to step S10.

If the above equation (B1) is satisfied in step S60, the flow advances to step S70 to reverse the sign of the output shaft rotational speed change rate dN _O. Then, step S8
At step S90, the flag F1 is set to 1, and at step S90, the number of times I that the synchronization condition is satisfied is reset to 0.
Proceed to. Then, the duty ratio D is determined based on the inverted value of the output shaft rotation speed variation rate dN _O and the turbine speed change rate dN _T outputted to the solenoid 19, then returns to step S10. In step S80, the flag F1 is set to 1
Is set in step S50 from the next time.
The process proceeds to step S100 in the determination of.

In step S100, it is determined whether or not the flag F2 is 0. This flag F2 has an initial value of 0, and is set to 1 when the reverse rotation of the turbine 3b is determined. Here, since the reverse rotation determination has not been made yet, the flag F2 is 0, and the process proceeds to step S110. Note that when the flag F2 is set to 1, step S1
Go to 50.

In step S110, the above (C1), (C
It is determined whether the turbine 3b is rotating in the reverse direction by using the expression 2). If the above equations (C1) and (C2) do not hold, the process proceeds to step S200. Then, if the synchronization condition satisfaction count I has reached the predetermined number of times I _max, the step S
Proceeds to 210, if the synchronization condition satisfaction count I does not reach the predetermined number of times I _max, the process proceeds to step S190. In step S190, the duty ratio D is determined based on the inverted value of the output shaft rotation speed variation rate dN _O and the turbine speed change rate dN _T outputted to the solenoid 19, then returns to step S10.

In step S110, the above (C1), (C
If 2) is satisfied, inverts the sign of the turbine speed change rate dN _T proceeds to step S120. Then, the flag F2 is set to 1 in step S130,
In step S140, the number of times of synchronization condition satisfaction I is reset to 0, and the process proceeds to step S190. Then, the inverted value to the output shaft rotation speed variation rate of the turbine rotation speed variation rate dN _T dN _O
The duty ratio D determined based on the inversion value of is output to the solenoid 19, and thereafter, the process returns to step S10. By setting the flag F2 to 1 in step S130, the process proceeds to step S150 in the determination of step S100 from the next time.

In step S150, a determination is made as to whether or not the result of the determination made in step S110 is correct using the above equation (C3). If the above equation (C3) does not hold, the process proceeds to step S200. Then, if the synchronization condition satisfaction count I has reached the predetermined number of times I _max, the step S
Proceeds to 210, if the synchronization condition satisfaction count I does not reach the predetermined number of times I _max, the process proceeds to step S190. In step S190, the duty ratio D is determined based on the inverted value of the inverted value and the output shaft rotation speed variation rate dN _O of the turbine speed change rate dN _T outputted to the solenoid 19, then returns to step S10.

[0049] When the above (C3) equation is satisfied in step S150, the re-inverts the sign of the turbine speed change rate dN _T proceeds to step S160. Then, in step S170, the flag F2 is reset to 0, and in step S180, the number of times I that the synchronization condition is satisfied is reset to 0,
Proceed to step S190. Then, the duty ratio D is determined based on the inverted value of the output shaft rotation speed variation rate dN _O and the turbine speed change rate dN _T outputted to the solenoid 19, then returns to step S10. Step S170
Resets the flag F2 to 0, so that from the next time on, the determination in step S100 is repeated in step S1.
You will go to 10.

Next, the automatic transmission of the present invention will be described with reference to FIG.
The operation of the shift control device will be described. FIG.
(A) shows the feedback system after neutral control is released.
The turbine rotation when the vehicle is moving backwards
Speed N_TAnd synchronous rotation speed (i₁× N _O)
ing. FIG. 4B shows the duty output to the solenoid 19.
And the time axis of the rate is shown in FIG.
(A). Here, each of the above formulas (A
2) Each threshold used in (B1), (C1) to (C3)
The values N1 to N5 are N1 = N2 = N5, N3 = N4 = N_T
The detection limit is set.

[0051] When the vehicle begins to retract, the output shaft of the automatic transmission 1 is reversely rotated, the actual synchronization speed (i ₁ × N _O) as shown by the solid line in FIG. 4 (a) negative direction (After time t1). At this time, since the output shaft rotation speed sensor 15 cannot detect the rotation direction of the output shaft as described above, the ECU 11 sets the synchronous rotation speed (i ₁ × N _O ) as shown by the dashed line in FIG. It recognizes that it is rising in the forward direction.

Further, the actual turbine rotational speed _NT gradually decreases as the synchronization of the forward clutch 7 progresses. Then, within the synchronization determination range for the synchronous rotation speed (i ₁ × N _O ) recognized by the ECU 11 [FIG.
(Within the range between two-dot chain lines)
2). However, in the present embodiment, when the vehicle speed is generated takes longer synchronization determination time (synchronization condition satisfaction count I is not determined that the synchronization when not reach the predetermined number of times I _max)
Since the way, decrease the actual turbine rotational speed N _T is further erroneous determination of determining the synchronization by the synchronization condition satisfaction count I is out of the synchronism determination range before reaching the predetermined number of times I _max (time t3) Prevention Is done.

Further, since the threshold value N1 for the synchronization determination and the threshold value N2 for the reverse determination are set to be equal, at the time t3 when the actual turbine rotational speed _NT is out of the synchronization determination range, the above equation (B1) is established. I do. As a result, the ECU 11 recognizes that the vehicle is moving backward, and changes the output shaft rotational speed change rate dN _O.
Is inverted. Therefore, after time t3, FIG.
As shown in (a), the actual synchronous rotation speed (i ₁ × N _O ) and EC
U11 since so that the synchronizing speed to recognize (i ₁ × N _O) coincide, as shown in FIG. 4 (b), it no proper feedback control can excessively reduce the output duty ratio D Becomes

When the synchronization of the forward clutch 7 further proceeds, the actual turbine rotational speed _NT falls below the detection limit value (forward direction detection limit value) (time t4). At this time, the above (C
Equation 1) holds. Then, the actual turbine rotation speed _NT eventually becomes zero, and starts reverse rotation in the reverse direction. As described above, the turbine rotation speed sensor 13
Cannot be detected, the turbine rotation speed _NT
ECU 11 recognizes that it is rising in the forward direction even if it is rising in the backward direction, but when the actual turbine rotational speed _NT is below the detection limit value,
Since the CU 11 recognizes the turbine rotation speed _NT as 0 as shown by the one-dot chain line in the figure, it does not adversely affect the feedback control.

When the actual turbine rotation speed _NT falls below the detection limit value (reverse direction detection limit value) (time point t5), the ECU 11 returns the turbine rotation speed _NT to the detection limit value (forward direction detection limit value). Value). However, at this time, since the (C2) equation is established, ECU 11 recognizes that the turbine 3b rotates in the reverse direction, to invert the sign of the turbine speed change rate dN _T. Therefore, even after the time point t5, the actual turbine rotation speed _NT and the turbine rotation speed _NT recognized by the ECU 11 match as shown in FIG.
As shown in (b), it is possible to perform appropriate feedback control without outputting an excessive duty ratio D.

Therefore, according to the present shift control device, in the feedback control performed after the neutral control is released, an appropriate duty ratio can be output even if the vehicle moves backward, and the delay in shifting to the first speed stage can be achieved. There is an advantage that troubles such as generation of a shock due to sudden engagement of the forward clutch 7 and the like can be prevented. Also,
According to the present shift control device, there is no need to provide a dedicated sensor for detecting the rotation direction of the turbine or the output shaft, so that there is an advantage that the cost does not increase.

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, the settings of the thresholds N1 to N5 used in the above equations (A2), (B1), (C1) to (C3) are not limited to those in the above embodiment, but may be set to any values. it can.

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.

[0059]

As described above in detail, according to the shift control apparatus for an automatic transmission of the present invention, when it is determined that the vehicle is moving backward, the parameter value related to the output shaft rotation speed used for feedback control is determined. Since the feedback control is performed based on the inverted parameter value, there is an advantage that the engaging force of the friction element can always be controlled to an appropriate value even when the vehicle moves backward.

According to the shift control device for an automatic transmission of the present invention, when it is determined that the vehicle is moving backward and the input shaft of the automatic transmission is rotating in the reverse direction, the input used for the feedback control is determined. Since the sign of the parameter value related to the absolute value of the shaft rotation speed is inverted and feedback control is performed based on the inverted parameter value, the engagement force of the friction element is always controlled to an appropriate value even when the vehicle moves backward. There is an advantage that can be.

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

FIG. 4 is a time chart showing control characteristics of a shift control device for an automatic transmission as one embodiment of the present invention;
(A) shows the turbine rotation speed _NT and the synchronous rotation speed (i ₁ × N
_O ) is a diagram showing a time change, and (b) is a diagram showing a time change of the output duty ratio.

FIG. 5 is a time chart showing control characteristics of the shift control device of the automatic transmission devised in the process of creating the present invention;
(A) is a diagram showing a time change of the rotation speed of the turbine shaft, (b) is a diagram showing control timing of a duty ratio of a solenoid, and (c) is a diagram showing a time change of a hydraulic pressure of a forward clutch.

FIG. 6 is a time chart showing control characteristics of a shift control device for an automatic transmission devised in the process of inventing the present invention;
(A) shows the turbine rotation speed _NT and the synchronous rotation speed (i ₁ × N
_O ) is a diagram showing a time change, and (b) is a diagram showing a time change of the output duty ratio.

[Description of Signs] 1 Automatic transmission 2 Engine 7 Forward clutch (friction element) 11 ECU 13 Turbine rotation speed sensor 15 Output shaft rotation speed sensor 30 Release control unit (feedback control means) 31 Synchronization determination unit 32 Reverse determination unit (Reverse Determination means) 33 reverse rotation determination unit (reverse rotation determination means) 34 parameter sign reversal unit (reversal means)

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Katsutoshi Usuki F-term (reference) 3J552 MA02 MA12 NA01 NB01 PA02 PA59 PA65 QB04 RB01 RB03 RB08 RB17 RB3-33-8 Shiba 5-chome, Minato-ku, Tokyo SA07 SA54 SA57 TA01 VA32W VA32Y VA33W VA33Y VA42Y VA48Z VB01Z VC01Z VC03Z VD11Z

Claims (2)

[Claims] When a predetermined condition is satisfied when a shift range of an automatic transmission is in a forward range and a friction element to be coupled during traveling is in a neutral state, the friction element is operated to a coupling state to perform a predetermined operation. A shift control device for an automatic transmission configured to achieve the above-mentioned shift speed, wherein the friction element is operated to a coupled state based on at least a parameter value related to an output shaft rotation speed of the automatic transmission. Feedback control means for feedback-controlling the engagement force of the friction element; reverse determination means for determining the vehicle reversal; when the reverse determination means determines that the vehicle is reversing, the sign of the parameter value is inverted. Inverting means for inverting the parameter value when the sign of the parameter value is inverted by the inverting means. Characterized in that it is configured to perform the feedback control on the basis of the inverted parameter value, the automatic transmission shift control device. 2. When a predetermined condition is satisfied when the shift range of the automatic transmission is in the forward range and the friction element to be coupled during traveling is in the neutral state, the friction element is operated to the coupled state to perform the predetermined operation. A shift control device for an automatic transmission configured to attain the above-mentioned shift speed, wherein the friction element is operated to a coupled state based on at least a parameter value related to an input shaft rotation speed of the automatic transmission. Feedback control means for performing feedback control of the engagement force of the friction element; reverse determination means for determining the backward movement of the vehicle; reverse rotation determination means for determining the reverse rotation of the input shaft; When the reverse rotation determining means determines that the input shaft is rotating in reverse, a reversing means for reversing the sign of the parameter value. And wherein when the sign of the parameter value is inverted by the inverting means, the feedback control means performs the feedback control based on the inverted parameter value. , Transmission control device for automatic transmission.