JP2708107B2 - Shift control device for automatic transmission for vehicle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention achieves multi-stage by a vehicle automatic transmission, in particular, a tandem arrangement of two transmissions, and a transmission combination of these two transmissions. The present invention relates to a shift control device for an automatic transmission for a vehicle.

2. Description of the Related Art Conventionally, an automatic transmission for a vehicle using two transmissions arranged in tandem is disclosed, for example, in JP-A-62-83541.

In such an automatic transmission for a vehicle, an auxiliary transmission is arranged in series with a main transmission, and it is possible to achieve multi-stage by combining the transmissions of these two transmissions. (Up side and down side)
, The overall speed is upshifted or downshifted.

Of the gears, for example, the main transmission is upshifted, the subtransmission is downshifted, and the overall second gear → 3
At the time of the upshift, which is a high speed, as shown in the time chart of FIG. 9, when the downshift of the subtransmission of the two transmissions ends first, as shown in the P portion of the torque characteristic in FIG. A large shift shock occurs.

Further, when the downshift of the auxiliary transmission of the two transmissions ends with a delay, a shift shock occurs to a lesser extent.

Therefore, in the above conventional example, as shown in the time chart of FIG. 11, by synchronizing the shift end timings of the two transmissions, shock reduction is achieved as an ideal characteristic as shown in FIG. I'm trying.

Specifically, the rotation of the input / output shaft of the transmission and the rotation of the intermediate shaft of the two transmissions are detected, which shift is completed first is determined, and the end of the shift at the next 2nd → 3rd speed shift There corrects the value of T _D to synchronize, synchronization shift end timing is performed by so-called learning control. At this time, the value of T _D is low and the correction value so as to converge.

(Problems to be Solved by the Invention) However, such a conventional shift control method for an automatic transmission for a vehicle is a control method for correcting the next shift start timing based on the result information of the current shift end timing. Therefore, if the engine torque, the fastening element, the control oil pressure, etc., change after the current 2nd → 3rd speed shift is performed and before the 2nd → 3rd speed shift is performed, Even if the next shift start timing correction control is performed using this information, the shift end timing is not synchronized and a shift shock occurs.

That is, when the same 2nd → 3rd speed shift is performed over a long period of time, the state of the engine and the automatic transmission greatly changes, and the same 2nd → 3rd speed shift is performed in a short time. Even in this case, it is rare that the states of the engine and the automatic transmission are completely the same, and when the shift timing control is performed by the learning control, as shown in the time chart of FIG. It is extremely difficult to synchronize the shift end timing of the transmission.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problem. In a shift control device for an automatic transmission for a vehicle having two transmissions arranged in tandem, the shift end timing of the two transmissions is shifted. It is an object of the present invention to surely reduce a shift shock during a simultaneous shift in which a shift shock occurs.

(Means for Solving the Problems) In order to solve the above problems, in the shift control device for an automatic transmission for a vehicle according to the present invention, the actual shift end timing is set to the target shift end timing based on the current shift end timing prediction information. In order to coincide with each other, the shift progress speed is corrected by the shift control and the engine output control during the current shift.

That is, as shown in the claim correspondence diagram of FIG. 1, the first transmission a and the second transmission
Transmission b is arranged in tandem, and these transmissions a,
The automatic transmission for a vehicle, which achieves a multi-stage transmission as a whole by simultaneously or alternately shifting b by first and second shift control means c and d, wherein the first transmission a and the second transmission A gear ratio calculating means h for calculating a gear ratio of the transmission b, and a gear ratio calculating means h during a gear shift when the first transmission a and the second transmission b start shifting based on a shift command. The first and second transmissions assume that the shift progresses at the same gear ratio change rate from the previous and current gear ratio changes calculated by
a shift end timing estimating means e for estimating the shift end timings of a and b; and, when the first and second transmissions a and b are simultaneously shifted, the actual shift end timing is determined based on the shift end timing prediction information. A shift which outputs a control correction command for correcting a shift progress speed by at least one of the both shift control means c and d and the engine output control means f during the shift so that the shift speed coincides with a target shift end timing for reducing the shift speed. And an end timing correction control means g.

(Operation) When the shift of the first transmission a and the second transmission b is started based on the shift command, the shift end timing estimating means e calculates the previous time calculated by the gear ratio calculating means h during the shift. The shift end timing of the first and second transmissions a and b is predicted assuming that the shift progresses at the same gear ratio change rate from the change in the gear ratio and the current gear ratio change. 1, during simultaneous shifting of the second transmissions a and b, both shift control during shifting so that the actual shift end timing matches the target shift end timing for reducing the shift shock based on the shift end timing prediction information. A control correction command for correcting at least one shift progress speed of the means c and d and the engine output control means f is output.

As described above, the shift end timing estimating means e assumes that the gear shift progresses at the same gear ratio change rate from the previous and current gear ratio changes calculated by the gear ratio calculating means h during the gear shift. Since it is means for predicting the shift end timing of the second transmissions a and b in real time, it is necessary to change the state of the past and present engines and automatic transmissions as in learning control performed using past shift time information. There is no shift in the shift end timing, and highly accurate shift end timing prediction can be performed regardless of past and present state changes.

Further, the shift end timing correction control unit g is a unit that corrects at least one shift progress speed of the two shift control units c and d and the engine output control unit f during the shift,
As in the case where the shift start timing, which is the time from the start of one shift to the start of the other shift, is controlled, there is no shift in shift end timing due to a change in state during shifting, and The timing can be matched with the target shift end timing at which the shift shock is reduced with high accuracy.

Therefore, during a simultaneous shift in which a shift shock occurs due to a shift in the shift end timing of the two transmissions a and b, the shift shock is reliably reduced regardless of the past and present state changes or state changes during the shift. You.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

That is, FIG. 2 is a schematic configuration diagram showing a power unit system to which a shift control device for an automatic transmission for a vehicle according to an embodiment of the present invention is applied, in which an engine 10 and an automatic transmission 20 are shown. , A first transmission 22 having a torque converter 21 and performing three forward speed changeovers
And a second transmission 23 in which two-stage switching between a speed increase and a constant speed is performed is arranged in dandem.

The engine 10 is equipped with an engine centralized electronic control system (ECCS) that controls a fuel injection device, an ignition device, an idle speed control device, and the like with a single control unit. It has various sensors and switches 11 that span information, an ECCS control unit 12 that outputs a predetermined control signal based on input information, and an actuator 13 such as a fail injector.

In the automatic transmission 20, a combination of three-stage switching by the first transmission 22 and two-stage switching by the second transmission 23 enables a total of six stages of shifting as shown in the following table. Become.

By the way, the first and second transmissions 22 and 24 are each engaged or disengaged by friction elements such as clutches and brakes incorporated in the respective gear trains, as generally performed in automatic transmissions. The shift is switched, and the engagement and release of the friction element is switched by a hydraulic pressure supplied from the control valve 24.

The control of the hydraulic pressure by the control valve 24 is A / A
This is performed by a control signal output from the T control unit 25, and a throttle opening sensor 26, a vehicle speed sensor 27, an oil temperature sensor 28, a turbine speed sensor 29, a drum speed sensor 30, etc. are connected to the control unit 25. And
A control signal corresponding to the vehicle operating condition input information from these is calculated. For example, the shift point control unit uses a throttle opening signal, a vehicle speed signal, and the like as vehicle operating conditions, and determines a shift point according to a shift schedule previously input to the A / T control unit 25.

Here, in the present embodiment, as shown in the above-mentioned shift operation table, the shift direction between the first transmission 22 and the second transmission 23 is in the A / T control unit 25 in the opposite direction. 2nd gear → up to 3rd gear or 4th gear →
A shift start for obtaining a fifth speed shift determination based on an internal shift command from the shift point control unit, starting an upshift of the first transmission 22, and then starting a downshift of the second transmission 23. The timing control unit predicts the shift end timings of the first and second transmissions 22 and 23 after the start of the shift by assuming that the shift progresses at the same change gear ratio change rate from the change in the previous and current gear ratios. The first transmission 22 and the second transmission 22 during the shift operation such that the actual shift end timing coincides with the target shift end timing for reducing the shift shock based on the shift end timing prediction unit and the shift end timing prediction information. Each transmission control unit of the transmission 23 and the ECCS control unit 12
A shift end timing correction control unit that outputs a control correction command to at least one of them.

 Next, the operation will be described.

FIG. 3 shows an example of a flow chart of the embodiment of the present invention, which is applied to the speed change control of Japanese Patent Application No. 62-83541 shown as a conventional example. The description is given with the same reference numerals.

Note that while this flow chart shows taking an example case where the upshift to the second speed to the third speed, also the upshift for fastening the brake B ₂ provided in the first transmission 22, the the brake B ₀ provided 2 of the transmission 23 is intended to be carried out by opening.

First, the flag T is set to zero. Since the flag T determined in step 800 is zero, a gear shift determination is made in the next step 900. If it is determined that, for example, the second speed is changed to the third speed, the oil temperature is determined in steps 902 and 904. throttle opening is monitored, and an upshift of the first transmission 22 is started by outputting a hydraulic pressure supply command to the brake B ₂ of the first transmission 22 at step 906.

Next, in step 1002, calculation of the gear ratios i ₁ and i ₂ between the first transmission 22 and the second transmission 23 is started by the following equation.

i ₁ = 1/1 (1 + α ₁ ) + α ₁ · N _co / N _t i ₂ = ｛(1 + α ₁ ) N _t −α ₁ · N _co ｝ / N _o α ₁ ; the planetary gear of the first transmission 22 Gear ratio (number of sun gear teeth) / (number of ring gear teeth) N _co ; rotation number of drum member N _t ; turbine rotation number N _o ; output shaft rotation number (obtained by vehicle speed sensor) The time T _D is determined from the start of the shift of the first transmission 22, the flag T is rewritten to 1 in step 802, and the time determination in step 908 is repeated. If T ≧ T _D , the process proceeds to step 910. , downshift second transmission 23 is started by outputting a hydraulic drain command to the brake B ₀ of the second transmission 23.

In step 1004, each prediction time T _E1 , T _E2 , T _e , and T _ED is calculated.

T _E1 ; Predicted time till the end of the shift of the first transmission 22 T _E2 ; Estimated time till the end of the shift of the second transmission 23 T _e ; T _E1 −T _E2 T _ED ; T _E1 or T _E2 is zero the difference between T _E1 and T _E2 when a namely, T _ED is positive when the T _ED when the first transmission 22 is completed earlier negative, the second transmission 23 is completed earlier .

The prediction of T _E1 and T _E2 is based on the previous and current gear ratio changes.
It is calculated by the following equation, assuming that the shift proceeds at the same gear ratio change rate (see FIG. 5).

i ₁ ; current gear ratio of first transmission 22 i ₂ ; current gear ratio of _second transmission 23 i _1e ; gear ratio of first transmission 22 after shifting i _1b ; first transmission The gear ratio i _2e of the previous transmission of the transmission 22; the gear ratio i _{2b of} the second transmission 23 after the shift; the gear ratio Δt of the previous transmission of the second transmission 23 Δt; the time step of the previous and current gear ratio calculation At 1006, it is determined whether T _E1 = 0 and T _E2 > 0, that is, whether the first transmission 22 is predicted to end before the second transmission 23, and if YES, the, the process proceeds to step 1008, command down is outputted to the engine output by the fail-cut or the like with a command to down the shelf pressure of the brake B ₂ is output.

In step 1010, the shift end predicted time difference T _e (T _E1 −
T _E2 ) exceeds the maximum allowable value T _emax (signed), and if YES, the process proceeds to step 1014,
Command for down shelf pressure of the brake B ₀ with down the shelf pressure of the brake B ₂ is output.

In step 1012, the shift end predicted time difference T _e (T _E1 −
T _E2 ) exceeds the minimum allowable value T _emin (signed), and in the case of YES, the process proceeds to step 1016,
Command for down by failure cut like an engine output with the command to up-shelf pressure of the brake B ₀ is output with up shelf pressure of the brake B ₂ is output. Further, when the determination result is NO in step 1012, i.e., if the shift end estimated time difference T _e is within the range of the maximum allowable value T _emax and minimum allowable value T _emin that does not require correction of shift end timing Then, go to step 914.

Is inertia phase T ₄ of the first transmission 22 in step 914 is measured, until a T ₄ rewrites the flag T is 2 in step 801, it is repeated shift end timing correction control from step 1004, T ₄ quick draining command brake B ₀ is issued in step 916 to the time after.

Next, in step 1018, the calculation of the gear ratios i ₁ and i ₂ between the first transmission 22 and the second transmission 23 ends.

In step 920, the throttle opening θ is determined whether constant, if not constant, without correction control time T _D from the shift start of the first transmission 22 starts to shift the second transmission 23 If it is constant,
Performs _TD correction control.

Whether step 1022 T _ED (target value of T _ED) (difference between the two when T _E1 or T _E2 becomes zero) is T _ED <T _EDI is determined, when T _ED ≧ T _EDI, the step Go to 928 and take T _D
Rewritten to T _D -t _D, when the T _ED <T _EDI process proceeds to step 924, rewrites the T _D to T _D + t _D, is corrected in accordance with the first transmission 22 the value of T ₄ is actually in Suepppu 926 You. Then, in step 803, the flag T is rewritten to 0.

The above t _D is a constant determined by the type of throttle opening and shifting.

Accordingly, in the case of a simultaneous shift in which the first and second transmissions 22 and 23 generate a shift shock due to a shift in the shift end timing, as in the case of the second speed to third speed shift, the timing chart shown in FIG. As shown in step 1002, both transmissions 22, 23
The gear ratios i ₁ and i ₂ are calculated, and it is predicted in step 1004 how the shift will end. In steps 1014 and 1026, the shift end timing target value T _EDI is calculated based on the shift end timing prediction information. Correction control is performed so as to approach.

Here, in terms of how to determine the shift end timing target value T _EDI , as shown in the shift torque characteristics in FIGS. 6 to 8, when T _ED > 0, the torque jumps out and the shift shock is large. When T _ED = 0, the torque waveform is the best and the shift shock is the minimum. When T _ED <0, a negative torque jumps out, but the shift shock does not increase as much as when T _ED > 0. Therefore, it is most preferable to set T _EDI = 0. In this case, however, there is a possibility that T _ED > 0 due to a shift in shift timing. Therefore, even if the shift end timing is shifted, the shift shock is reduced. In order to suppress this, the correction control is performed by setting the shift end timing target value T _{EDI at} which T _ED becomes slightly negative. In addition, in step 1008, control is performed to minimize the torque jump-out when the second transmission 23 has finished shifting first.

As described above, in the shift control device of the embodiment, the shift end timing correction control is performed during the current shift based on the current shift end timing prediction information.
The shift end timing is not shifted due to a change in the state of the engine or the automatic transmission as in the case where the shift timing control is performed by learning control, and the first and second transmissions 22 and 23 are not shifted.
The synchronization of the gear shift end timing is achieved with high accuracy, and the gear shift shock can be reliably reduced.

Also, even if the shift end timing shifts due to some unpredictable cause, the shift end timing target value T
_{Since EDI} is set slightly negative, shift shock can be reduced.

Further, even if the second transmission 23 has already completed the shifting, the control in step 1008 minimizes the time lag and reduces the engine output by the command in step 1008. Can be prevented from occurring.

In the above-described embodiment, the shift is shifted up as a whole by the first transmission 22 being upshifted and the second transmission 23 being downshifted. Without limitation, the first transmission 22 is downshifted and the second transmission 23 is upshifted, so that the upshift is performed as a whole, or two other transmissions are arranged in tandem. Of course, the present invention can be applied to a simultaneous transmission in which the shift shock occurs due to a shift in the shift end timing between the two transmissions.

(Effects of the Invention) As described above, according to the present invention, in a vehicle automatic transmission having two transmissions arranged in tandem, the gears of the first transmission and the second transmission are provided. A gear ratio calculating means for calculating a ratio;
It is assumed that, when the transmission of the second transmission and the transmission of the second transmission are started, the shift proceeds at the same gear ratio change rate from the change of the previous and current gear ratios calculated by the gear ratio calculation means during the shift. A shift end timing estimating means for estimating shift end timings of the first and second transmissions, and an actual shift end timing based on shift end timing prediction information at the time of simultaneous shifts of the first and second transmissions. Shift end timing correction control for outputting a control correction command for correcting a shift progress speed by at least one of the both shift control means and the engine output control means during the shift so that the target shift end timing is made smaller. Means during the simultaneous shift in which a shift shock occurs due to a shift in the shift end timing of the two transmissions. The effect is obtained that the shift shock can be surely reduced irrespective of the state change.

[Brief description of the drawings]

FIG. 1 is a claim correspondence diagram showing a shift control device for a vehicle automatic transmission according to the present invention, and FIG. 2 is a schematic configuration diagram showing a power unit system to which the shift control device for a vehicle automatic transmission according to the embodiment is applied. FIG. 3 is a flowchart showing an example of processing when the control of the present invention is executed. FIG. 4 is a time chart showing a shift relationship in the first and second transmissions of the present invention. FIG. 6 is a conceptual diagram for explaining the shift end timing prediction in the example, FIG. 6 is a transmission torque characteristic diagram when the second transmission ends the shift first, and FIG. 7 is the first transmission and the second transmission.
Transmission torque characteristic diagram when the transmission of
FIG. 8 is a transmission torque characteristic diagram when the second transmission ends the shift with a delay, FIG. 9 is a time chart showing the relationship of the conventional transmission, FIG. 10 is a characteristic diagram of the conventional transmission torque, and FIG. The figure is a time chart showing the relationship of conventional ideal shifting,
FIG. 12 is a characteristic diagram of a conventional ideal transmission torque. a ... first transmission b ... second transmission c ... first transmission control means d ... second transmission control means e ... shift end timing prediction means f ... engine output control means g ... Shift end timing correction control means h ... Gear ratio calculation means

Claims (1)

(57) [Claims] A first transmission and a second transmission that automatically shift to at least two or more stages are arranged in tandem, and these transmissions are simultaneously or alternately controlled by first and second shift control means. An automatic transmission for a vehicle that achieves a multi-stage transmission by shifting the gears as a whole; a gear ratio calculating means for calculating a gear ratio between the first transmission and the second transmission; When the transmission of the second transmission and the transmission of the second transmission are started, it is assumed that the shift progresses at the same gear ratio change rate from the change of the previous and current gear ratios calculated by the gear ratio calculation means during the shift. A shift end timing estimating means for estimating shift end timings of the first and second transmissions, and an actual shift end timing based on shift end timing prediction information during simultaneous shifts of the first and second transmissions. Reduce shift shock A shift end timing correction control unit that outputs a control correction command for correcting a shift progress speed by at least one of the two shift control units and the engine output control unit during the shift so that the shift end timing coincides with the target shift end timing. A shift control device for an automatic transmission for a vehicle, comprising: