JP4052169B2 - Shift control device for automatic transmission - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention controls the torque of a power source during shifting by engaging a shifting friction element so that the effective gear ratio follows the target gear ratio and shifts from the gear ratio before shifting to the gear ratio after shifting to prevent shifting shock. The present invention relates to a shift control apparatus for an automatic transmission.
[0002]
[Prior art]
As a technique for controlling the torque of the engine that is a power source during the shift of the automatic transmission, a technique for operating the throttle opening of the engine during the shift of the automatic transmission as described in Patent Document 1 has heretofore been known. It has been known.
[0003]
[Patent Document 1]
Japanese Patent Laid-Open No. 9-229176
[Problems to be solved by the invention]
By the way, the conventional engine torque control through throttle opening control has a large engine torque change rate with respect to the throttle opening change, and can secure a large torque control amount, but the engine intake amount by the throttle opening change. Because the response delay of the change is relatively large, when trying to make the effective gear ratio follow the target gear ratio by engine torque control via throttle opening control during gear shifting, the effective gear ratio is targeted with the required response. There is a problem in that it is difficult to follow the gear ratio, and it is difficult to achieve a good shift feeling as intended.
[0005]
In the present invention, the torque control technology during gear shifting is not limited to the throttle opening control, but an engine (power) that is capable of precise torque control although a large torque control amount cannot be obtained unlike the throttle opening control. Based on the fact that there is ignition timing control
An automatic transmission that enables the effective gear ratio to follow the target gear ratio with the required response by combining the throttle opening control and the ignition timing control, thereby realizing the desired gear change feeling. An object of the present invention is to provide a shift control apparatus.
[0006]
On the other hand, when trying to make the effective gear ratio follow the target gear ratio by torque control of the power source during gear shifting, the required effective gear ratio operation speed is high and a large torque control amount is required in the first half of the gear shifting period. On the other hand, in the latter part of the speed change period, fine adjustment of the effective gear ratio is required and high-accuracy torque control is required.
Based on this fact recognition, the present invention uses the torque control during shifting by throttle opening control and ignition timing control to match different torque control characteristics in the first and second stages of the shift period, respectively. It is also an object of the present invention to provide a shift control device for an automatic transmission that can provide a suitable shift feeling.
[0007]
[Means for Solving the Problems]
For these purposes, a shift control device for an automatic transmission according to the present invention is as described in claim 1.
Assuming an automatic transmission in which the power source is torque controlled so that the effective gear ratio follows the target gear ratio and is shifted from the pre-shift gear ratio to the post-shift gear ratio during a shift by engaging a shift friction element. ,
The shift period is divided into a first half and a second half. In the first half, the torque control of the power source is executed by a combination of throttle opening control and ignition timing control. In the second half, the torque control of the power source is performed. Configured to execute by ignition timing control,
Further, according to the deviation of the effective gear ratio from the target gear ratio during the transition process to the complete engagement of the speed change friction element , which is started when the effective gear ratio matches the post-shift gear ratio. In order to eliminate this divergence, the ignition timing control of the power source is executed following the latter period.
[0008]
【The invention's effect】
According to the speed change control apparatus of the present invention, the power source for causing the effective gear ratio to follow the target gear ratio in the first half of the speed change period in which the required effective gear ratio operation speed is high and a large torque control amount is required. On the other hand, in the latter part of the gear shift period when precise adjustment of the effective gear ratio is required and high-precision torque control is required, the effective gear ratio is adjusted. Since the torque control of the power source to follow the target gear ratio is performed by the ignition timing control of the power source,
In the first half of the shift period where high response torque control is required, the effective gear ratio can be made to follow the target gear ratio with the required response by using the throttle opening control and the ignition timing control in combination.
Also, in the latter part of the shift period where delicate torque control is required, the ignition timing control allows the effective gear ratio to follow the target gear ratio with the required high accuracy,
A suitable shift feeling as intended can be realized over the entire shift period. Moreover, since the ignition timing control of the engine is executed continuously after the latter period of the shift period so that the effective gear ratio matches the target gear ratio, the engine blow-off phenomenon that may occur after the latter period. Can also deal with.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 shows a power train of a vehicle provided with a shift control device for an automatic transmission according to an embodiment of the present invention, together with its control system. 1 is an engine (may be an electric motor) as a power source, 2 is It is an automatic transmission including a continuously variable transmission, and the power train of the vehicle is constituted by these tandem connections.
The output of the engine 1 is adjusted by a throttle valve 4 that increases in opening from fully closed to fully open in conjunction with an accelerator pedal 3 operated by a driver, and the engine output is automatically shifted through a torque converter T / C. Assume that it is input to the machine 2.
[0010]
The opening degree of the throttle valve 4 of the engine 1 is basically determined by the accelerator pedal 3, but the opening degree of the throttle valve 4 can be controlled by the throttle actuator 5, so that the engine output torque can be adjusted as described later for countermeasures against shift shocks. To be able to do.
The throttle opening degree control by the throttle actuator 5 is performed by the engine controller 6, and the engine controller 6 can also adjust the engine output torque for countermeasures against the shift shock by the ignition timing control of the engine 1.
[0011]
The engine controller 6 is not dedicated to throttle opening control and ignition timing control for the above-described shift shock countermeasure, but performs normal engine control such as fuel injection amount control. Inputs a signal from the throttle opening sensor 7 that detects the throttle opening TVO of the throttle valve 4 and a signal from the engine rotation sensor 8 that detects the engine speed Ne.
[0012]
The automatic transmission 2 is a linear motion that directly controls the hydraulic fluid pressure to be supplied to a frictional element for shifting such as a hydraulically operated clutch or a hydraulically operated brake that determines a power transmission path (shift stage) of the gear transmission system. Therefore, hydraulic fluid duty solenoids 12, 13, and 14 are provided in the control valve 11 for speed change control by the number of the friction elements for speed change.
These hydraulic fluid duty solenoids 12, 13, and 14 individually control the hydraulic fluid pressure of the corresponding friction elements, and selectively engage the friction elements to operate the automatic transmission 2 at a predetermined gear position. Allow it to be selected.
The automatic transmission shifts and outputs the engine power at a gear ratio corresponding to the selected shift speed.
[0013]
The drive duty of the duty solenoids 12, 13, and 14 is determined by the transmission controller 15, and the transmission controller receives the throttle opening (TVO) signal from the sensors 7 and 8 and the engine via the engine controller 6. In addition to inputting the rotation speed (Ne) signal, the engine controller 6 inputs a signal related to the actual engine torque (Te) obtained from the internal information, and further detects an input rotation speed Ni of the automatic transmission 2. 16 and a signal from the output rotation sensor 17 for detecting the output rotation speed No of the automatic transmission 2 are input.
[0014]
The transmission controller 15 executes a known control program (not shown) based on the input information described above, and controls the automatic transmission 2 as follows.
First, based on a vehicle speed VSP and a throttle opening TVO obtained by calculation from the transmission output rotational speed No, a gear stage suitable for the current operating state is obtained based on a planned shift pattern (not shown).
If the preferred shift speed matches the currently selected shift speed, the drive duty of the duty solenoids 12, 13, 14 is maintained as it is by not issuing a shift command not to perform a shift. The current selected gear position is maintained.
However, if the currently selected shift speed is different from the preferred shift speed, a shift command is issued to change the drive duty of the corresponding duty solenoids 12, 13, and 14, thereby shifting from the selected shift speed to the preferred shift speed. The release of the friction element for shifting and the fastening switching are executed.
[0015]
By the way, in the present embodiment, at the time of the gear shift, the engine torque control amount for preventing the shift shock is determined as shown in FIG. 3 by executing the control program shown in FIG.
In FIG. 3, the hydraulic fluid pressure Po of the disengagement friction element to be released at the time of shifting is lowered as shown in the figure to change the friction element from the engaged state to the disengaged state. The hydraulic fluid pressure Pc is increased as shown in the figure to change the friction element from the released state to the engaged state. By switching these friction elements, the high-side selected shift stage (third speed) is changed to the low-side suitable shift stage (first stage). The downshift when shifting to 2nd gear will be described.
[0016]
As described later in detail, the transmission controller 15 obtains an engine torque increase amount | Ttvo | by increasing the throttle opening and an engine torque feedback control amount | Trtd | by ignition timing control. In response to the engine controller 6, the throttle opening control and / or ignition timing control by the throttle actuator 5 increases the output torque of the engine 1 by a torque increase amount | Ttvo | and a feedback control amount | Trtd | Only amend it.
[0017]
The control program in FIG. 2 shows processing by the transmission controller 15, and is assumed to start at the instant t1 in FIG. 3 when the shift command is issued.
First, in step S1, an inertia in which the effective gear ratio Gr (= Ni / No) represented by the ratio between the transmission input / output rotational speeds Ni and No changes from the pre-shift gear ratio G1 to the post-shift gear ratio G2. A target output torque waveform that defines a time-series change in transmission output torque To to be targeted during the phase is selected.
Although this target output torque waveform is not shown, it is set as a combination of the target inertia phase time Δt1 and the target inertia phase torque Tos,
Based on the type of shift, the vehicle speed VSP, the throttle opening TVO, the transmission input torque Ti (for the sake of convenience, this is treated as the same as the engine torque Te), the transmission output torque To is the output torque before the shift ( It is previously determined by experiment or the like with the aim of changing from Ti × G1) to the post-shift output torque (Ti × G2) in a suitable manner for gear shift shock countermeasures.
Next, in step S2, a target inertia phase time Δt1 and a target inertia phase torque Tos are set from the selected target output torque waveform.
[0018]
In step S3, the target gear ratio Gr during the inertia phase is calculated as follows.
First, by multiplying the transmission input torque Ti by a constant α corresponding to the target inertia phase torque Tos, the target engagement capacity Tdt (= Ti × α) in the inertia phase of the engagement side friction element is calculated, and at the time of this shift From the target engagement capacity Tdt and the above target inertia phase time Δt1, the target engine torque Tet in the inertia phase is calculated as follows.
That is, the rotational inertia coefficient I of the rotating portion on the engine side with respect to the engagement-side friction element, the input rotational step ΔNi from the pre-shift value to the post-shift value of the transmission input rotational speed Ni, and the target engagement capacity Tdt in the inertia phase And the target engine torque Tet in the inertia phase
I × ΔNi ＝ Tdt−Tet
Is established, and the target engine torque Tet in the inertia phase is calculated using this equation.
Then, the waveform of the target engine torque Tet at the inertia phase is set from the target engine torque Tet in the inertia phase and the target inertia phase time Δt1.
[0019]
Here, the calculation procedure of the target gear ratio Grt will be described with respect to the calculation of the target gear ratio Grt1 when a certain time has elapsed from the start of the inertia phase.
The input rotational step ΔNi1 between the start of the inertia phase (the transmission input rotational speed at this time is Ni1) and the target transmission input rotational speed Nit1 when the certain time has passed from then is the inertia phase From the target engagement capacity Tdt at the time, the target engine torque Tet at the inertia phase, and the rotational inertia coefficient I described above,
ΔNi1 = (Tdt−Tet) / I
Can be obtained by the following calculation.
[0020]
Then, the transmission input rotation speed at the start of the inertia phase is Ni1, and the input rotation step ΔNi1 described above, the target transmission input rotation speed Nit1 when the certain time has elapsed is
Nit ＝ Ni1−ΔNi1
Can be obtained.
Next, the target gear ratio Grt1 (= Nit1 / No) can be obtained by dividing the target transmission input rotational speed Nit1 at the time when the certain time elapses by the transmission output rotational speed No at the same instant. .
By executing the above calculation step by step, the target gear ratio Grt during the inertia phase can be obtained as shown by a broken line in FIG.
[0021]
In the next step S4, as shown in FIG. 3, a timer value Ts1 for starting torque up and a timer value Ts2 for ending torque up are set starting from the shift command time t1.
In step S5, it is determined whether or not the shift has ended. In this determination, the shift end determination is made based on whether or not the effective gear ratio Gr has steadily settled to the post-shift gear ratio, or from the shift command instant t1. The end of the shift is checked based on whether or not the set time has passed.
If the shift is complete, the control is terminated. If the shift is not complete, the following shift control is executed.
[0022]
In step S6, whether or not the timer TM measuring the elapsed time from the shift command instant t1 has reached the timer value Ts1 for starting torque increase set in step S4, or the effective gear ratio Gr is the torque. It is checked whether or not the instant t2 in FIG. 3 at which the engine torque for the shift shock prevention should be increased is reached depending on whether or not the set gear ratio Gs1 (not shown) for starting up is reached.
Control is returned to step S5 until the moment t2 is reached, and the determination in step S5 and step S6 is continued, and in step S7, the torque increase is determined (commanded) in step S6. Based on the gear ratio Gr and the engagement capacity (operating hydraulic pressure) of the disengagement side friction element, the engine torque increase amount Ttvo by throttle opening control required for preventing the shift shock is calculated as shown in FIG.
[0023]
Next, in step S8, an engine torque increase start command by throttle opening control is issued, and in step S9, an engine torque increase amount Ttvo by throttle opening control is transmitted to the engine controller 6.
The engine controller 6 receives the signal related to the engine torque increase amount Ttvo, and increases the throttle opening TVO by the throttle actuator 5 so that the torque increase is realized.
[0024]
Thereafter, in step S10, it is determined whether or not the inertia phase start instant indicated by t3 in FIG. 3 has been reached, depending on whether or not the effective gear ratio Gr is equal to or greater than the inertia phase start determination gear ratio, and the above loop is executed until the start of the inertia phase. Repeatedly, after the start of the inertia phase, it is determined in step S11 whether or not the inertia phase end instant indicated by t5 in FIG. 3 has been reached.
During the inertia phase in which it is determined in step S11 that the inertia phase has not ended, in step S12, the timer TM that measures the elapsed time from the shift command instant t1 is the torque increase end timer set in step S4. The engine torque increase for stopping the shift shock should be terminated depending on whether the value Ts2 has been reached, or whether the effective gear ratio Gr has reached the set gear ratio Gs2 (not shown) for terminating the torque increase. It is checked whether or not an instant t4 of 3 has been reached.
[0025]
If it is determined after step t10 that the inertia phase is started, after the moment t3, the step t11 determines that the inertia phase is in progress. In the case where it is determined by the direct selection of S13, or when it is determined in step S12 that the moment t4 at which the engine torque increase for preventing the shift shock should be finished is reached, the selection of step S13 after the selection of step S14 makes the above-described target An engine torque feedback control amount Trtd based on ignition timing control for calculating the gear ratio deviation ΔGr of the effective gear ratio Gr with respect to the gear ratio Grt (Gr = Grt) is calculated.
[0026]
Next, in step S15, the engine torque feedback control amount | Trtd | by ignition timing control is transmitted to the engine controller 6.
The engine controller 6 receives the signal related to the engine torque feedback control amount Trtd and adjusts the ignition timing of the engine 1 so that the engine torque feedback control amount is realized.
Even when it is determined in step S12 that the instant t4 at which the engine torque increase for preventing shift shock is to be finished has been reached, the processing in steps S13 and S15 is continued as described above so that the effective gear ratio Gr becomes the target gear ratio Grt. The engine torque feedback control by the ignition timing control that follows is continued, but when it is determined that the instant t4 has been reached, in addition to that, in step S14, the engine torque increase amount Ttvo by the throttle opening control is set to zero. This is transmitted to the engine controller 6 to finish the torque increase of the engine by the throttle opening control as shown in FIG.
[0027]
When it is determined in step S11 that the moment of inertia phase end indicated by t5 in FIG. 3 has been reached, in step S16, the same processing as in step S13 is performed, according to the gear ratio deviation ΔGr of the execution gear ratio Gr with respect to the target gear ratio Grt. Further, an engine torque feedback control amount Trtd by ignition timing control for setting (Gr = Grt) is calculated.
Next, in step S17, the engine torque feedback control amount | Trtd | by ignition timing control is transmitted to the engine controller 6.
The engine controller 6 receives the signal related to the engine torque feedback control amount Trtd and adjusts the ignition timing of the engine 1 so that the engine torque feedback control amount is realized.
After execution of step S17, control is returned to step S5, and the above loop is repeated.
[0028]
By the way, according to the present embodiment, the effective gear ratio Gr is made to follow the target gear ratio Grt in the first to third periods t3 to t4 of the shift period in which the required effective gear ratio operation speed is high and a large torque control amount is required. Engine torque control is performed by using throttle opening control (Ttvo) and ignition timing control (Trtd) in combination (steps S9 and S13). On the other hand, fine adjustment of the effective gear ratio Gr is required and high-precision torque control is required. From the latter t4 to t5 of the shift period in which engine speed is required, engine torque control for causing the effective gear ratio Gr to follow the target gear ratio Grt is performed by ignition timing control (Trtd) (step S14 and step S13).
The effective gear ratio Gr can be made to follow the target gear ratio Grt with the required response by combining the throttle opening control and the ignition timing control in the first half of the shift period in which high response torque control is required. 3 can be shortened as indicated by γ, the shift time as indicated by β,
Also, in the latter part of the shift period where delicate torque control is required, the ignition gear control allows the effective gear ratio Gr to follow the target gear ratio Grt with the required high accuracy.
A suitable shift feeling as intended can be realized over the entire shift period.
[0029]
The above-described effect is obtained by dividing the boundary t4 between the first period t3 to t4 of the shift period and the latter period t4 to t5 of the shift period, and a period in which the required effective gear ratio operation speed is high and a large torque control amount is required. Of course, it is possible to achieve the most prominent by setting a boundary with a period in which fine adjustment of the effective gear ratio is required and high-accuracy torque control is required.
[0030]
Further, according to the present embodiment, during the transition to the full engagement of the engagement side friction element as shown in FIG. 3 executed at the instant t5 when the effective gear ratio Gr coincides with the post-shift gear ratio Grt, the effective ratio with respect to the target gear ratio Grt. In accordance with the deviation ΔGr of the gear ratio Gr, the ignition timing control of the engine is executed from the latter t4 to t5 of the shift period and after the instant t5 so that the deviation disappears and the effective gear ratio Gr matches the target gear ratio Grt. Therefore (step S16 and step S17), it is possible to eliminate the engine blow-off phenomenon that may occur after the instant t5.
[Brief description of the drawings]
FIG. 1 is a system diagram showing a power train of a vehicle including a shift control device for an automatic transmission according to an embodiment of the present invention, together with its control system.
FIG. 2 is a flowchart showing a shift control program to be executed by the transmission controller in the same embodiment together with an engine torque control program executed by the engine controller for shift control.
FIG. 3 is a time chart showing a shift control operation in the same embodiment.
[Explanation of symbols]
1 Engine 2 Automatic transmission 3 Accelerator pedal 4 Throttle valve 5 Throttle actuator 6 Engine controller 7 Throttle opening sensor 8 Engine rotation sensor
11 Control valve
12 Duty solenoid
13 Duty solenoid
14 Duty solenoid
15 Transmission controller
16 Transmission input rotation sensor
17 Transmission output rotation sensor

Claims (2)

During a shift by engaging the shift friction element, the effective gear ratio represented by the ratio of the transmission input rotation speed to the transmission output rotation speed is made to follow the target gear ratio, and the gear ratio before the shift is changed to the gear ratio after the shift. Therefore, in an automatic transmission in which the power source is torque controlled,
The shift period is divided into a first half and a second half. In the first half, the torque control of the power source is executed by a combination of throttle opening control and ignition timing control. In the second half, the torque control of the power source is performed. Configured to execute by ignition timing control,
Further, according to the deviation of the effective gear ratio from the target gear ratio during the transition process to the complete engagement of the speed change friction element , which is started when the effective gear ratio matches the post-shift gear ratio. A shift control apparatus for an automatic transmission, characterized in that ignition timing control of the power source is executed subsequent to the latter period so as to eliminate this deviation. The shift control device according to claim 1, wherein the effective gear ratio is adjusted at a boundary between the first and second periods of the shift period, a period in which the required effective gear ratio operation speed is high and a large torque control amount is required. A shift control device for an automatic transmission, characterized in that it is a boundary between a required period and high-accuracy torque control.

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