JP2004316838A - Gear change unit of automatic transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To surely attenuate the shock of gear change even if the torque rise for avoiding a torque drop is not sufficient at an engine torque upper limit. <P>SOLUTION: The drop of the output torque shown in the dotted line of (a) is dissolved by the waveform of an engine torque TeU at the time of torque increase, which realizes the aimed waveform To(t) in the correspondent period and the subsequent aimed output torque waveform To(t) is realized by the torque decrease TeD and the aimed shelf pressure Pco. When the TeU is restricted to the upper limit value of the engine torque Teup as (b) and the deficiency in the torque increase shown in the hatching part is caused, it is improved only to the degree that shows in (b) with a chain line although the drop as shown in (a) with a dotted line is improved only to the degree as shown in (b) with a chain line and the subsequent steep increase becomes big. In this case, Pco is recalculated to a value (which becomes lower as Teup becomes smaller) shown by (b) so that the torque difference level does not become big around t2 and the torque waveform of TeU is the torque waveform simultaneously so that it is increasing gradually toward Teup between t2 from t1. Thereby, the torque waveform shown in (b) with the chain line is improved as shown with the dotted line. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shift control device for an automatic transmission that increases the torque of a power source such as an engine (performs a torque increase) in order to advance a shift as scheduled.
[0002]
[Prior art]
2. Description of the Related Art As a torque-up technique for reducing a shift shock by causing a shift to proceed as planned during a shift of an automatic transmission, a shift-time torque-up technique such as that described in Patent Document 1 is conventionally known. ,
As a technique for appropriately controlling the engagement capacity of the friction element for shifting in order to reduce the shift shock, a technique for feedback-controlling the clutch pressure in accordance with the engine torque as described in, for example, Japanese Patent Application Laid-Open No. H11-216, is known.
[0003]
[Patent Document 1]
JP-A-7-127490
[Patent Document 2]
Japanese Patent Publication No. 6-056204
[0004]
The torque increase technique during shifting described in Patent Document 1 is based on the following concept.
At the time of an upshift from the low gear to the high gear, for example, as shown in FIG. 18A, the engagement pressure Pc of the engagement friction element to be engaged in the gear is increased as shown in FIG. The engagement pressure of the release-side friction element to be released is omitted) The shift is advanced.
[0005]
In the torque phase, which is the previous stage of the inertia phase, in which the effective gear ratio represented by the ratio of the transmission input / output rotation speed changes from the pre-shift gear ratio to the post-shift gear ratio, it is used to prevent the engine from blowing. Due to the overlap in which the engagement-side friction element and the release-side friction element are engaged together, the transmission output torque To is drawn in, for example, as shown by a dashed line in FIG. , A thrust shock is generated.
[0006]
In order to eliminate the pull-in of the transmission output torque To generated in the torque phase as shown by the solid line, the torque up at the time of the upshift is performed by increasing the engine torque command value Tes by Δteu to make it like TeU. It is.
The above-mentioned thrust shock in the inertia phase is reduced by a torque-down control such as TeD by reducing the engine torque command value Tes by Δted.
[0007]
At the time of a downshift from the high gear to the low gear, for example, as shown in FIG. 19A, the engagement pressure Po of the release-side friction element to be released during the gear shift is reduced as shown in the figure ( The engagement pressure of the engagement-side friction element to be engaged is omitted) The shift is advanced.
In the torque phase during shifting, the transmission output torque To is drawn in, for example, as shown by a broken line in the same figure as in the upshift, to generate a pulling shock, and in the subsequent inertia phase to generate a thrust shock.
[0008]
In order to eliminate the pull-in of the transmission output torque To generated in the torque phase as shown by the solid line, the torque increase at the time of the downshift is performed by increasing the engine torque command value Tes by Δteu to make it like TeU. According to this, at the same time, the transmission response can be enhanced as is clear from the comparison of the transmission output torque (To) waveform shown by the broken line with the transmission output torque (To) waveform shown by the solid line.
The above-mentioned thrust shock in the inertia phase is reduced by a torque-down control such as TeD by reducing the engine torque command value Tes by Δted.
[0009]
[Problems to be solved by the invention]
Incidentally, the engine has a torque range that can be realized according to the performance and the operating state, and the upper limit of the engine torque is also determined.
In other words, the engine torque is usually increased by operating the throttle opening and controlling the ignition timing.However, for high rotation, high load operation, etc., the throttle opening of the engine is set to a large opening near full opening, or the ignition timing is increased. Cannot be realized even if there is a large torque-up command.
[0010]
Under such a condition, a predetermined shift shock reduction effect cannot be expected with the torque-up technology described in Patent Document 1.
That is, when the engine torque upper limit Telmt is large and the torque-up engine torque TeU is smaller than the engine torque upper limit Telmt as shown in FIGS. And improved shift response as scheduled,
As shown in FIGS. 18 (b) and 19 (b), when the engine torque upper limit Telmt is small and the torque-up engine torque TeU is larger than the engine torque upper limit Telmt, FIGS. As is clear from the comparison between the transmission output torque (To) waveform shown by the dashed line and the broken line and the transmission output torque (To) waveform shown by the solid line in (b), the torque increase shortage indicated by hatching is apparent. However, the above-described effect of reducing the retraction shock and improving the shift response cannot be realized as scheduled.
[0011]
On the other hand, even if the technique described in Patent Document 2 is used in such a state and the engagement pressure of the friction element is feedback-controlled according to the torque increase shortage, the engagement of the friction element having a low control response is originally achieved. Because the pressure is the control target, and because of the low response due to the feedback control, the torque step of the transmission output torque cannot be reliably absorbed sufficiently, and a sufficient shift shock countermeasure is expected. There is a problem that can not be.
[0012]
In other words, at the time of the upshift, as shown in FIG. 18C, the engagement pressure Pc of the engagement-side friction element is reduced by feedback control corresponding to the torque-up shortage indicated by hatching, whereby the transmission output is reduced. Although the level after the pull-in indicated by the one-dot chain line of the torque To is suppressed, the level of the transmission output torque To immediately after the pull-in cannot be greatly reduced due to the poor control response due to the feedback control described above, and the transmission output In addition to the fact that the pull-in indicated by the one-dot chain line of the torque To is the same as that in FIG. 18B, the torque step of the transmission output torque To cannot be reduced as shown by the solid line in FIG. However, there is a problem that the feeling of torque thrust immediately after the pull-in cannot be sufficiently eliminated.
[0013]
At the time of a downshift, as shown in FIG. 19 (c), the engagement pressure Po of the disengagement-side friction element is reduced by feedback control corresponding to the torque-up shortage indicated by hatching, whereby the transmission output is reduced. Although the shift response is slightly increased by the improvement of the torque To from the torque waveform shown by the broken line to the torque waveform shown by the solid line, the level of the transmission output torque To immediately after the pull-in is greatly reduced due to the poor control response due to the feedback control described above. 19, the torque step of the transmission output torque To cannot be reduced as shown by the solid line in FIG. 19A, and the sense of torque thrust immediately after pull-in cannot be sufficiently eliminated. There is.
[0014]
The present invention compensates for insufficient torque increase due to the torque upper limit of the power source by correcting the engagement pressure of the shifting friction element. However, based on the fact that the above problem is caused by a response delay due to feedback control in response to the insufficient torque increase. It is another object of the present invention to provide a shift control device for an automatic transmission in which the above-mentioned problem can be solved by performing the correction by feedforward control instead of feedback control.
[0015]
[Means for Solving the Problems]
To this end, a shift control device for an automatic transmission according to the present invention has the following features.
A power source torque upper limit value calculation means, a power source torque calculation means at the time of torque increase, and a speed control device of the automatic transmission configured to increase the torque of the power source in order to advance the shift as scheduled. , A target engagement pressure setting means, a power source torque control means, and a friction element engagement control means.
[0016]
The power source torque upper limit value calculation means obtains a power source torque upper limit value that can be generated during the above-mentioned shift at the time of a shift command.
The torque-up power source torque calculating means obtains a torque-up power source torque generated by the power source due to the torque increase at the time of a shift command.
If the target engagement pressure setting means determines that the power source torque at the time of torque increase exceeds the power source torque upper limit value based on signals from these means at the time of a gearshift command, the gearshift friction to be changed during the gearshift is used. The target engagement pressure of the element is set based on the power source torque upper limit value.
The power source torque control means controls the power source so that the output torque becomes equal to the torque upper limit value during shifting, when the torque at the time of torque increase exceeds the power source torque upper limit value.
When the power source torque at the time of torque increase exceeds the power source torque upper limit value, the friction element engagement control means controls the engagement of the transmission friction element during gear shifting such that the engagement pressure becomes the target engagement pressure.
[0017]
【The invention's effect】
According to the shift control device of the present invention, when the torque increase shortage due to the torque upper limit value of the power source is compensated for by the engagement pressure correction of the shifting friction element, the correction is performed by feedforward control.
Even if the target of the correction is the engagement pressure of the shifting friction element, the problem regarding low response in the case of feedback control does not occur, and the output torque step immediately after the torque phase during shifting is reliably absorbed and absorbed. It can be made small, and sufficient shift shock countermeasures can be guaranteed.
[0018]
BEST MODE FOR CARRYING OUT 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 a control system thereof. 1 is an engine (or an electric motor) as a power source. An automatic transmission including a continuously variable transmission forms a power train of a vehicle by tandem coupling of these.
The output of the engine 1 is adjusted by a throttle valve 4 whose opening increases from fully closed to fully opened as the accelerator pedal 3 is depressed in conjunction with an accelerator pedal 3 operated by the driver, and the engine output is automatically shifted through a torque converter T / C. It is assumed that the information is input to the device 2.
[0019]
The throttle valve 4 of the engine 1 is electronically controlled by a throttle actuator 5 in accordance with the depression amount (accelerator opening amount) APO of the accelerator pedal 3 basically. The opening degree can also be controlled in response to this, so that the engine output torque can be adjusted as described below to cope with a shift shock.
The throttle opening degree control by the throttle actuator 5 is performed by the engine controller 6, and the engine controller 6 can adjust the engine output torque to cope with the shift shock by controlling the ignition timing of the engine 1.
[0020]
The engine controller 6 is not dedicated to the throttle opening control and the 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 an accelerator opening sensor 7 for detecting an accelerator pedal depression amount APO and a signal from an engine rotation sensor 8 for detecting an engine speed Ne.
[0021]
The automatic transmission 2 is a linear motion that directly controls a hydraulic pressure to be supplied to a gearshift friction element such as a hydraulic clutch or a hydraulic brake that determines a power transmission path (gear stage) of a gear transmission system. Therefore, the hydraulic pressure duty solenoids 12, 13, 14 are provided in the control valve 11 for speed change control by the number of the friction elements for speed change.
These hydraulic hydraulic duty solenoids 12, 13, and 14 individually control the hydraulic pressures of the corresponding frictional elements by duty, and selectively engage the corresponding frictional elements, thereby setting the automatic transmission 2 to a predetermined gear position. Be ready to be in a selected state.
Then, the automatic transmission shifts and outputs the engine power at a gear ratio corresponding to the selected shift speed.
[0022]
The drive duties of the duty solenoids 12, 13, and 14 are determined by a transmission controller 15, which includes a throttle opening (TVO) signal from sensors 7, 8 via an engine controller 6 and an engine. In addition to inputting the rotation speed (Ne) signal, the engine controller 6 inputs a signal relating to the actual engine torque (Te) obtained from the internal information and a signal relating to the engine torque upper limit Teup. A signal from the input rotation sensor 16 for detecting the number Ni and a signal from the output rotation sensor 17 for detecting the output rotation number No of the automatic transmission 2 are input.
[0023]
The engine torque upper limit Teup is the upper limit of the engine torque that can be generated in the current operating state, and is determined by the engine controller 6 corresponding to the power source torque upper limit calculating means as follows.
FIG. 6 is a functional block diagram showing a calculation process of the engine torque upper limit Teup, and a first engine torque upper limit calculator 21 for calculating an engine torque upper limit Telmt1 in consideration of the fuel consumption of the engine;
A second engine torque upper limit calculator 22 that calculates an engine torque upper limit Telmt2 in consideration of the controllability of the electronically controlled throttle valve;
A third engine torque upper limit calculator 23 that calculates an engine torque upper limit Telmt3 in consideration of the exhaust of the diesel engine;
A fourth engine torque upper limit calculator 24 that calculates an engine torque upper limit Telmt4 in consideration of noise and vibration;
A fifth engine torque upper limit calculator 25 that calculates an engine torque upper limit Telmt5 in consideration of switching of the engine operation mode;
The engine torque upper limit value selector 26 is provided.
[0024]
The first engine torque upper limit value calculation unit 21 performs the processing of FIG. 7 and the engine speed Ne and the accelerator pedal depression amount APO (even with the throttle opening TVO of the throttle valve 4) based on the engine torque upper limit map of FIG. Good), an engine torque upper limit Telmt1 is retrieved and set in consideration of the fuel efficiency of the engine.
Here, in the engine torque upper limit value map in consideration of the fuel efficiency shown in FIG. 8, although the fuel efficiency is different for each engine, the fuel efficiency deterioration area is defined by the engine speed Ne and the accelerator pedal depression amount APO (throttle opening TVO) as shown in FIG. Therefore, when the torque is increased, the map is set to an engine torque upper limit Telmt1 that prevents the engine torque Te from being set to a torque value corresponding to the fuel consumption deterioration region. The smaller the driving condition, the lower the fuel efficiency.
[0025]
The region where the fuel efficiency of the engine deteriorates (operating state) differs from engine to engine, but generally becomes as shown in FIG. 9. It is reasonable to do.
[0026]
When the second engine torque upper limit value calculation unit 22 in FIG. 6 determines that the engine is a gasoline engine by the processing in FIG. 10, based on the engine torque upper limit value map in FIG. 11, the engine speed Ne and the accelerator pedal depressed. From the amount APO (throttle opening TVO may be used), an engine torque upper limit Telmt2 is retrieved and set in consideration of controllability of the electronically controlled throttle valve.
Here, the engine torque upper limit value map in consideration of the controllability of the electronically controlled throttle valve shown in FIG. 11 is used when the electronically controlled throttle valve is in an operation state in which the opening degree is too large. Since the sensitivity becomes low and the throttle valve fluctuates, a map is set in which the engine torque upper limit Telmt2 is determined so as to prevent this.
[0027]
To explain the basis for the map as shown in FIG. 11, the lower the engine speed Ne, the lower the intake flow velocity and the smaller the torque change with respect to the throttle opening (TVO) change, so that the accelerator pedal operation amount tends to increase. For this reason, the engine torque upper limit Telmt2 is set to a small value on the assumption that the opening degree of the electronically controlled throttle valve becomes too large as the engine speed Ne becomes lower.
Also, since the throttle opening (TVO) tends to increase as the accelerator pedal depression amount APO increases, the electronic control type throttle valve has an excessively large opening degree as the accelerator pedal depression amount APO increases. The engine torque upper limit Telmt2 is set to be small.
[0028]
Further, in FIG. 10, when it is determined that the engine is not a gasoline engine, since the electronically controlled throttle valve is not used, there is no operation state in which the opening of the electronically controlled throttle valve becomes too large. The engine torque upper limit Telmt2 in consideration of controllability is determined as the engine torque maximum.
[0029]
When the third engine torque upper limit value calculation unit 23 in FIG. 6 determines that the engine is a diesel engine by the processing in FIG. 12, based on the engine torque upper limit value map in FIG. From the amount APO (throttle opening TVO may be used), an engine torque upper limit Telmt3 in consideration of exhaust from the diesel engine is searched and set.
Here, the engine torque upper limit map considering the exhaust shown in FIG. 13 is different for each diesel engine, but the exhaust deterioration area is defined by the engine speed Ne and the accelerator pedal depression amount APO (throttle opening TVO), for example, as shown in FIG. 14. Therefore, when the torque is increased, an engine torque upper limit Telmt3 is defined as a map that prevents the engine torque Te from being set to a torque value corresponding to the exhaust deterioration area. The smaller the setting, the more harmful the operating condition of the engine exhaust.
[0030]
The region in which the exhaust of the diesel engine deteriorates (operating state) differs from engine to engine, but generally becomes as shown in FIG. 14. Therefore, the operating state in which the exhaust deteriorates as the engine is in a high load and high revolution range. Is appropriate.
[0031]
In FIG. 12, when it is determined that the engine is not a diesel engine, the engine torque upper limit Telmt3 in consideration of the exhaust of the diesel engine is determined as the maximum value of the engine torque because the above-described problem regarding the exhaust of the diesel engine does not occur.
[0032]
The fourth engine torque upper limit value calculation unit 24 in FIG. 6 performs the processing in FIG. 15 and the engine speed Ne and the accelerator pedal depression amount APO (throttle opening TVO may be used) based on the engine torque upper limit value map in FIG. ), An engine torque upper limit Telmt4 in consideration of engine noise and vibration is retrieved and set.
Here, the engine torque upper limit map in consideration of noise and vibration shown in FIG. 16 shows an engine torque upper limit Telmt4 that prevents the engine torque Te from being set to a torque value corresponding to the noise and vibration deterioration region when the torque increases. As a determined map, the engine torque upper limit Telmt4 is set to be smaller as the operating state in which the engine noise and the vibration increase.
It is appropriate that the region (operating state) where the noise and vibration of the engine deteriorates is an operating state where the noise and vibration worsen as the engine has a higher load and a higher rotation speed.
[0033]
The fifth engine torque upper limit calculator 25 in FIG. 6 calculates the engine torque upper limit Telmt5 in consideration of the switching of the engine operation mode by the processing in FIG.
In FIG. 17, it is sequentially determined whether or not the engine is switching between stratified combustion and homogeneous combustion, whether or not the exhaust gas recirculation device is being switched on or off, and further, whether or not the engine valve timing is being switched. Check if it is not.
If the engine operation mode is not being switched, the engine torque upper limit Telmt5 is set as the maximum torque value that can be realized by the engine, and the engine torque is allowed to increase. If the engine operation mode is being switched, the engine torque upper limit is set. Telmt5 is set to the same torque value as the engine torque requested by the driver obtained from the accelerator pedal depression amount APO so that the engine torque is not increased.
Thus, it is possible to prevent the torque from being increased and the combustion from deteriorating when the engine operation mode is being switched.
[0034]
The engine torque upper limit value selecting unit 26 of FIG. 6 selects the smallest one of the engine torque upper limit values Telmt1, Telmt2, Telmt3, Telmt4, and Telmt5 obtained by the arithmetic units 21 to 25 as described above, respectively, and selects FIG. As described above, the engine torque upper limit value Teup to be commanded from the engine controller 6 to the transmission controller 15 is set.
[0035]
The transmission controller 15 executes a well-known control program (not shown) based on the input information including the engine torque upper limit Teup to control the automatic transmission 2 in the following manner.
First, from the vehicle speed VSP and the throttle opening TVO calculated from the transmission output rotational speed No, a shift speed suitable for the current operation state is determined based on a planned shift pattern not shown.
If the preferred gear and the currently selected gear are the same, the gearshift is not performed and no gearshift command is issued to maintain the drive duty of the duty solenoids 12, 13, and 14 as they are. , Maintain the current selected gear.
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 frictional element for shifting is released and the engagement is switched.
[0036]
By the way, in the present embodiment, at the time of the upshift, if the upshift is performed, the control program shown in FIG. 2 is executed in response to the upshift command, and as shown in FIG. The engagement pressure Pc of the side friction element (in FIG. 4, the engagement pressure of the release side friction element is omitted) is determined,
In the case of a downshift, by executing the control program shown in FIG. 3 in response to the downshift gearshift command, as shown in FIG. 5, a torque up / down command to the engine controller 6 and the engagement pressure Po of the release-side friction element (in FIG. , The fastening pressure of the fastening-side friction element is omitted).
[0037]
In the course of these shifts, the transmission controller 15 obtains a torque-up target engine torque TeU, as will be described in detail later, and combines this with a well-known torque-down target engine torque TeD (see FIGS. 18 and 19). As shown in FIG. 1, the output torque of the engine 1 is received by the engine controller 6 by the throttle opening control or the ignition timing control by the throttle actuator 5 during the torque phase and becomes the target engine torque TeU at the time of torque increase, and during the inertia phase the torque is increased. It is assumed that the downtime target engine torque TeD is set.
[0038]
First, the control at the time of the upshift performed as shown in FIG. 4 by the control program of FIG. 2 will be described.
The transmission controller 15 starts the control program of FIG. 2 at the moment when the upshift command is issued, and executes the steps S11 to S15 only once at the time of the upshift command. Based on the calculation result, at step S16, an engine torque up / down command (the torque down command is omitted because it is not related to the present invention, but is assumed to be the same as the above-described conventional TeD) by feedforward control. The engagement pressure Pc of the engagement-side friction element is controlled in a time-series manner.
[0039]
In step S11, the time-series change of the transmission output torque To to be targeted during the period from the instant t1 in FIG. 4A to the end of the shift in which the transmission output torque To starts to change (decrease) due to the shift is defined. The selected target output torque waveform To (t) is selected.
The target output torque waveform To (t) is set as illustrated by the solid line in FIG. 4A, and the type of shift (2 → 3 shift, 3 → 4 shift), the vehicle speed VSP, and the throttle opening TVO are set. During the predetermined target torque phase time and the target inertia phase time, the transmission output torque To shifts from the pre-shift output torque to the post-shift output torque through the predetermined inertia phase torque based on the transmission input torque and the like. It is determined in advance by an experiment or the like aiming at a place that changes in a suitable manner for shock measures.
[0040]
Next, in step S12, the target shelf pressure Pco relating to the engagement pressure Pc of the engagement-side friction element is calculated from the selected target output torque waveform To (t) and the transmission input torque as shown in FIG. 4A.
In step S13 corresponding to the torque-up power source torque calculating means, the output torque To at the instant t2 in FIG. 4 (a) is canceled by the dashed line and the output torque To is changed to the target output torque waveform To (t) shown by the solid line. The engine torque TeU at the time of torque increase, which is obtained by adding the amount of torque increase required to come, is obtained from the target shelf pressure Pco and the target output torque waveform To (t).
[0041]
In step S14, it is determined whether or not the torque-up engine torque TeU is equal to or less than the engine torque upper limit Teup from the engine controller 6.
As shown in FIG. 4A, if the engine torque upper limit Teup is large and TeU ≦ Teup, the operating state is such that the torque-up engine torque TeU can be completely realized without being limited to the engine torque upper limit Teup. By performing the feedforward shift control in step S16 without returning control to step S13 via step S15, in this shift control, the target shelf pressure Pco obtained as described above in step S12 and the target shelf pressure Pco obtained in step S13 are used. The torque-up engine torque TeU obtained as described above is used as it is.
[0042]
In this case, the pull-in of the output torque To shown by the broken line in FIG. 4A is canceled by the waveform of the torque-up engine torque TeU realized without being limited to the engine torque upper limit Teup, and the target torque in the corresponding period is eliminated. The output torque waveform To (t) can be realized, and the subsequent target output torque waveform To (t) can also be realized by the engine torque down TeD and the target shelf pressure Pco, so that good shift quality can be achieved. It is.
[0043]
However, as shown in FIG. 4B, when the engine torque upper limit Teup is small and TeU> Teup, the torque-up engine torque TeU is limited to the engine torque upper limit Teup, and only the hatched portion is torque limited. Since the increase cannot be realized as scheduled, the torque increase is insufficient.
In this case, the pull-in of the output torque To indicated by the broken line in FIG. 4A can be improved only to the level indicated by the dashed line in FIG. The push-up of the torque To also increases, and the shift shock cannot be sufficiently improved.
[0044]
In order to solve this problem, in the present embodiment, when the engine torque upper limit value Teup is small and TeU> Teup, step S14 in FIG. 2 advances the control to step S15 corresponding to the target engagement pressure setting means. The target shelf pressure Pco is recalculated as follows, and the control is returned to step S13. Here, the waveform of the torque-up engine torque TeU is calculated again as follows.
Therefore, step S13 corresponds to a torque-up target power source torque setting means.
[0045]
The recalculation of the target shelf pressure Pco in step S15 is performed based on the engine torque upper limit Teup. Even when the torque-up engine torque TeU is limited to the engine torque upper limit Teup, the output torque at the pull-in instant t2 is obtained. The target shelf pressure Pco is set to a value as exemplified in FIG. 4B (the engine torque upper limit value Teup is small) so that the torque step between the output torque and the subsequent output torque does not cause a large shift shock. (Lower shelf pressure).
Even if the target shelf pressure Pco is reduced by the recalculation as described above, the above-described target torque phase time is not changed. Therefore, the engagement of the engagement-side friction element during the instants t1 to t2 in FIG. The pressure Pc becomes gentler than the change rate of the fastening pressure Pc between the instants t1 and t2 in FIG.
[0046]
In the recalculation of the torque-up engine torque (TeU) waveform in step S13, the torque-up engine torque TeU starts to gradually increase from the engine torque value at the torque-up start instant t1, as shown by the solid line in FIG. Then, the torque waveform is determined so as to reach the engine torque upper limit Teup just at the torque-up end instant t2.
After the recalculation of the target shelf pressure Pco in step S15 and the recalculation of the torque-up engine torque (TeU) waveform in step S13 at the time of the upshift command, step S14 performs control based on the determination of TeU ≦ Teup. The process proceeds to step S16, in which the feedforward shift control after the shift command is performed based on the recalculated target shelf pressure Pco and the torque-up engine torque (TeU) waveform.
Therefore, step S16 corresponds to power source torque control means and friction element engagement control means.
[0047]
The target shelf pressure Pco that has been recalculated and the engagement pressure Pc of the engagement-side friction element that is gradually increased during the instants t1 to t2 in FIG. 4B are output torque at the instant t2. The pull-in of To and the subsequent increase in the output torque To can be reduced as is apparent from the output torque (To) waveform shown by the solid line in FIG. Shock can be sufficiently improved.
When the insufficient torque increase due to the engine torque upper limit Teup is compensated for by the correction of the engagement pressure Pc (target shelf pressure Pco) of the engagement-side friction element, the correction is performed by the feedforward control. Even with the engagement pressure Pc of the engagement-side friction element, a problem regarding low response in the case of feedback control does not occur, and a sufficient shift shock countermeasure can be ensured by ensuring the above-described operation and effect.
[0048]
Next, the control at the time of the downshift performed as shown in FIG. 5 by the control program of FIG. 3 will be described.
The transmission controller 15 starts the control program of FIG. 3 at the moment when the downshift command is issued, and executes steps S21 to S25 only once when the downshift command is issued. In step S26, the engine torque up / down command (the torque down command is not related to the present invention and its description is omitted because it is not related to the present invention, but is assumed to be the same as that of the conventional TeD described above) in a time series by feedforward control. And the engagement pressure Po of the release-side friction element is controlled in a time-series manner.
[0049]
In step S21, a target output torque waveform To (t) that defines a time-series change of the transmission output torque To to be a target during the shift is selected.
The target output torque waveform To (t) is set as illustrated by a solid line in FIG. 5A, and the type of shift (4 → 3 shift, 3 → 2 shift), the vehicle speed VSP, and the throttle opening TVO are set. In addition, the transmission output torque To is determined in advance by an experiment or the like with the aim of changing the transmission output torque To from the pre-shift output torque to the post-shift output torque in a manner suitable for a shift shock countermeasure based on the transmission input torque or the like. .
[0050]
Next, in step S22, a target decrease gradient θ related to the engagement pressure Po of the solution-side friction element is calculated from the selected target output torque waveform To (t) and the transmission input torque and set as shown in FIG. .
In step S23 corresponding to the power source torque calculating means at the time of increasing the torque, the pull-in of the output torque To shown by the broken line in FIG. ) Is obtained from the target engagement pressure (Po) decrease gradient θ and the target output torque waveform To (t).
[0051]
In step S24, it is determined whether or not the torque-up engine torque TeU is equal to or less than the engine torque upper limit Teup from the engine controller 6.
As shown in FIG. 5A, if the engine torque upper limit Teup is large and TeU ≦ Teup, the operating state is such that the torque-up engine torque TeU can be completely realized without being limited to the engine torque upper limit Teup. By performing the feedforward shift control in step S16 without passing through step S25, the target engagement pressure (Po) decreasing gradient θ obtained as described above in step S22 and the above-described in step S23 during this shift control. The torque-up engine torque TeU obtained as described above is used as it is.
[0052]
In this case, the pull-in of the output torque To indicated by the broken line in FIG. 5A is canceled by the waveform of the torque-up engine torque TeU realized without being limited to the engine torque upper limit Teup, and the target output torque waveform To (t) can be realized, and the target output torque waveform To (t) thereafter can also be realized by the torque down TeD of the engine, so that good shift quality can be achieved.
[0053]
However, as shown in FIG. 5B, when the engine torque upper limit Teup is small and TeU> Teup, the torque-up engine torque TeU is limited to the engine torque upper limit Teup, and only the hatched portion is torque limited. Since the increase cannot be realized as scheduled, the torque increase is insufficient.
In this case, the pull-in of the output torque To and the shift response delay indicated by the broken line in FIG. 5A are caused by the insufficient torque increase, and can be improved only to the level indicated by the dashed line in FIG. 5B.
[0054]
In order to solve this problem, in the present embodiment, when the engine torque upper limit Teup is small and TeU> Teup, step S24 in FIG. 3 advances the control to step S25 corresponding to the target engagement pressure setting means. The target engagement pressure (Po) decrease gradient θ is calculated again as follows.
The re-calculation of the target engagement pressure (Po) decrease gradient θ in step S25 is performed based on the engine torque upper limit Teup, and even when the torque-up engine torque TeU is limited to the engine torque upper limit Teup, the minimum is obtained. FIG. 5B illustrates a target engagement pressure (Po) decrease gradient θ in order to improve the speed limit response and, if possible, aim at a point where the torque step due to the pull-in of the output torque does not become small. (The lower the engine torque upper limit Teup, the steeper the slope).
[0055]
After the recalculation of the target engagement pressure (Po) decreasing gradient θ in the above-described step S25 is performed at the time of the downshift gearshift command, the feedforward shift control after the gearshift command in step S16 is performed by the recalculated target engagement pressure ( Po) Based on the decrease gradient θ and the torque-up engine torque (TeU) waveform.
Therefore, step S16 corresponds to power source torque control means and friction element engagement control means.
[0056]
Therefore, unlike the broken line in FIG. 5B, which shows the same variation as in FIG. 5A, the decrease in the release-side engagement pressure Po is indicated by a solid line by recalculating the target engagement pressure (Po) decrease gradient θ. It is performed with a series change, and the torque-up engine torque TeU is limited by the engine torque upper limit Teup, and is actually set to a value determined by the waveform shown by the solid line instead of the waveform shown by the broken line.
As a result, the torque waveform indicated by the one-dot chain line of the transmission output torque To can be changed to the torque waveform indicated by the solid line, and at the time of insufficient torque increase, at least the shift response can be improved as in FIG. it can.
[0057]
When the insufficient torque increase due to the engine torque upper limit Teup is compensated for by the correction of the engagement pressure Po (the target decrease gradient θ) of the release-side friction element, the correction is performed by the feedforward control. Even with the engagement pressure Po of the disengagement-side friction element, the problem of low response in the case of the feedback control does not occur, and the above-described operation and effect can be ensured and sufficient improvement of the shift response can be guaranteed.
[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 a control system thereof.
FIG. 2 is a flowchart showing a control program to be executed by the transmission controller during an upshift in the embodiment.
FIG. 3 is a flowchart showing a control program to be executed by the transmission controller at the time of downshifting in the embodiment.
FIG. 4 is an operation time chart according to the control of FIG. 2;
(A) is a time chart when the torque increase is sufficient,
(B) is a time chart when torque increase is insufficient.
FIG. 5 is an operation time chart based on the control of FIG. 3;
(A) is a time chart when the torque increase is sufficient,
(B) is a time chart when torque increase is insufficient.
FIG. 6 is a functional block diagram illustrating a calculation process of an engine torque upper limit value.
FIG. 7 is a flowchart of a control program showing processing by a first engine torque upper limit value calculation unit in FIG. 6;
FIG. 8 is a characteristic diagram showing a change characteristic of an engine torque upper limit value when fuel efficiency is considered.
FIG. 9 is a region diagram illustrating a fuel consumption deterioration region.
FIG. 10 is a flowchart of a control program showing a process by a second engine torque upper limit value calculator in FIG. 6;
FIG. 11 is a characteristic diagram showing a change characteristic of an engine torque upper limit value for a gasoline engine.
FIG. 12 is a flowchart of a control program showing a process by a third engine torque upper limit value calculator in FIG. 6;
FIG. 13 is a characteristic diagram showing a change characteristic regarding an engine torque upper limit value of a diesel engine.
FIG. 14 is a region diagram illustrating an exhaust deterioration region of the diesel engine.
FIG. 15 is a flowchart of a control program showing a process by a fourth engine torque upper limit value calculator in FIG. 6;
FIG. 16 is a characteristic diagram showing a change characteristic of an engine torque upper limit value when noise and vibration are considered.
FIG. 17 is a flowchart of a control program showing a process by a fifth engine torque upper limit value calculator in FIG. 6;
FIG. 18 is an operation time chart showing control at the time of an upshift by the conventional device,
(A) is a time chart when the torque increase is sufficient,
(B) is a time chart when torque increase is insufficient.
(C) is a time chart when the engagement pressure of the friction element is feedback-controlled when the torque increase is insufficient.
FIG. 19 is an operation time chart showing control at the time of downshifting by the conventional device;
(A) is a time chart when the torque increase is sufficient,
(B) is a time chart when torque increase is insufficient.
(C) is a time chart when the engagement pressure of the friction element is feedback-controlled when the torque increase is insufficient.
[Explanation of symbols]
1 engine
2 Automatic transmission
3 accelerator pedal
4 Throttle valve
5 Throttle actuator
6 Engine controller
7 Accelerator 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
21 First Engine Torque Upper Value Calculation Unit
22 Second Engine Torque Upper Value Calculation Unit
23 Third Engine Torque Upper Value Calculation Unit
24 Fourth Engine Torque Upper Value Calculation Unit
25 Fifth Engine Torque Upper Value Calculation Unit
26 Engine torque upper limit selection section

Claims (15)

In a shift control device for an automatic transmission, the torque is increased to increase the torque of a power source in order to advance a shift as scheduled.
A power source torque upper limit value calculating means for obtaining a torque upper limit value of the power source that can be generated during the shift, at the time of a shift command;
A torque-up power source torque calculating means for calculating a torque-up power source torque generated by the power source due to the torque increase, which is obtained at the time of a shift command,
When it is determined that the power source torque at the time of torque increase exceeds the power source torque upper limit value based on signals from these means at the time of a gearshift command, the target engagement pressure of the friction element for gearshift to be changed during the gearshift is determined by the power source. Target engagement pressure setting means for setting based on the torque upper limit value,
Power source torque control means for controlling the power source during shifting to control the output torque to be the torque upper limit when the power source torque at the time of torque increase exceeds the power source torque upper limit value;
When the power source torque at the time of torque increase exceeds the power source torque upper limit value, frictional element engagement control means for controlling the engagement of the transmission friction element during gear shifting so that the engagement pressure becomes the target engagement pressure is provided. A shift control device for an automatic transmission. The shift control device according to claim 1, wherein when the shift is an upshift, when it is determined that the torque-up power source torque exceeds a power source torque upper limit value at an upshift shift command, A torque-up target power source torque setting means for setting a target torque during torque-up to be smoothly increased from the power source torque at the start of torque-up to the power source torque upper limit value,
The power source torque control means controls the power source during shifting so that the output torque becomes the target power source torque at the time of increasing the torque instead of the torque upper limit value. Control device. 3. The shift control device according to claim 1, wherein when the shift is an upshift, a shelf pressure is set to a target engagement pressure of an engagement-side friction element to be changed from a release state to an engagement state during the shift. ,
A shift control device for an automatic transmission, wherein the target engagement pressure setting means sets a shelf pressure of the engagement-side friction element based on a power source torque upper limit value. 4. The automatic transmission according to claim 3, wherein the target engagement pressure setting means sets the shelf pressure of the engagement-side friction element to be lower as the power source torque upper limit value is smaller. Transmission control device. 2. The shift control device according to claim 1, wherein the target engagement pressure setting unit determines that, when the shift is a downshift, the torque-up power source torque exceeds a power source torque upper limit value at the time of a downshift shift command. When determining, the target engagement pressure reduction speed of the release-side friction element to be changed from the engagement state to the release state at the time of the gear shift is set based on the power source torque upper limit value,
The shift control device for an automatic transmission, wherein the friction element engagement control means controls the engagement of the speed change friction element such that an engagement pressure decreases at the target engagement pressure reduction rate during a gear shift. 6. The automatic transmission control device according to claim 5, wherein the target engagement pressure setting means increases a target engagement pressure decreasing speed of the release-side friction element as the power source torque upper limit value decreases. Transmission control device for transmission. 7. The transmission control device according to claim 1, wherein the power source torque upper limit value calculation unit sets the power source torque upper limit value to be smaller as the driving state in which the fuel efficiency of the power source deteriorates. 8. A shift control device for an automatic transmission, comprising: 8. The speed change control device according to claim 7, wherein the power source torque upper limit value calculating means is in an operating state in which the fuel efficiency of the power source deteriorates as the power source has a higher load and a higher rotation speed. Transmission control device for an automatic transmission. 7. The transmission control device according to claim 1, wherein the power source torque upper limit value calculating unit is configured to operate the power source electronically controlled throttle valve as the opening degree of the electronically controlled throttle valve becomes too large. A shift control device for an automatic transmission, wherein a source torque upper limit value is set to be small. 10. The speed change control device according to claim 9, wherein the power source torque upper limit value calculating means has a large accelerator pedal depression amount, which is a control factor when controlling the opening degree of the electronically controlled throttle valve, and the power source torque. A shift control device for an automatic transmission, wherein an opening degree of the electronically controlled throttle valve becomes too large as the number of revolutions becomes lower. 7. The transmission control device according to claim 1, wherein the power source torque upper limit value calculating unit operates in a driving state in which exhaust from the diesel engine is harmful when the power source is a diesel engine. 8. A shift control device for an automatic transmission, wherein the upper limit of the power source torque is set smaller as the power source torque increases. 12. The speed change control device according to claim 11, wherein the power source torque upper limit value calculation means is in an operating state in which exhaust is harmful due to high load and high speed operation of the diesel engine. Transmission control device for automatic transmission. 7. The shift control device according to claim 1, wherein the power source torque upper limit value calculating unit increases the power source torque upper limit value in an operation state in which the power source generates more noise and vibration. 8. A shift control device for an automatic transmission, which is set to a small value. 12. The transmission control device according to claim 11, wherein the power source torque upper limit value calculating means is in an operation state in which a high load and a high speed operation of the power source generate a large amount of noise and vibration. Transmission control device for automatic transmission. 7. The transmission control device according to claim 1, wherein the power source torque upper limit value calculating unit sets the power source torque upper limit value while the power source is switched between a combustion mode and a control mode. 8. A shift control device for an automatic transmission, wherein the shift control device is set to a value at which torque is not increased.

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