JP3539308B2 - Lockup control device for automatic transmission - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a lockup control technique for an automatic transmission that locks up a torque converter even during coasting of a vehicle to improve fuel efficiency.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, as a technique for temporarily releasing lockup during traveling, a technique disclosed in Japanese Patent Application Laid-Open No. 3-189471 is known.
[0003]
The purpose of this conventional source is to provide a control device for a continuously variable transmission having a lock-up fluid coupling that can effectively utilize the fluid coupling and improve running performance not only at the time of starting but also at the time of acceleration. An apparatus is described that includes means for quickly determining the presence or absence of acceleration and means for temporarily releasing lockup when an acceleration signal is input in a lockup state.
[0004]
[Problems to be solved by the invention]
However, in the prior art, since the acceleration signal for temporarily releasing the lockup is determined from the viewpoint of the driver's acceleration operation, the lockup is always performed if the accelerator pedal depression speed is equal to or higher than the set fixed value. There is a problem that the lockup is temporarily released, and the frequency of lockup release is high, which hinders improvement in fuel efficiency.
[0005]
On the other hand, when the accelerator is depressed from the coast lockup state, there is a problem that a so-called jerky vibration is generated as described in JP-A-8-177540. The jerky vibration is caused by the natural vibration of the drive system due to the step torque input to the drive system when the throttle opening shifts from a constant opening including a fully closed state to a high opening stepwise. Vibration that changes the longitudinal acceleration applied to the vehicle.
[0006]
Therefore, there is a possibility that the torque converter exerts a fluid coupling function by temporarily releasing the lock-up, thereby absorbing the torque fluctuation to suppress the rattling vibration.
[0007]
On the other hand, when the conventional technology is applied and the threshold value of the accelerator depression speed is set to a fixed value, there are the following problems.
[0008]
(1) If a low fixed value is set in the low vehicle speed range or the low gear ratio range where the rattling vibration is the most severe, the rattling vibration hardly occurs, or the vibration level is small even if it occurs. In a high vehicle speed range or a high gear ratio range, lockup is released more than necessary, which hinders improvement in fuel efficiency.
[0009]
(2) Jerky vibration is less likely to occur, or even if it occurs, the vibration level is small, and if it is set to a high fixed value under the condition of high gear ratio range, at low vehicle speed range or low gear ratio region, However, the occurrence of the rattling vibration is allowed, and the occurrence of the rattling vibration that is originally aimed at cannot be suppressed.
[0010]
The present invention has been made in view of the above problem, and the switching speed threshold for temporarily releasing the lock-up is switched by a parameter correlated with the level (easiness of occurrence) of the rattling vibration, whereby the rattling is achieved. An object of the present invention is to provide a lock-up control device for an automatic transmission that can achieve both suppression of generation of vibration and improvement of fuel efficiency.
[0011]
[Means for Solving the Problems]
According to the first aspect of the present invention, there is provided a lock-up control device for an automatic transmission including lock-up control means for engaging and operating a lock-up clutch of a torque converter even during coasting of a vehicle,
The vehicle speed at the start of accelerator depression correlated with the jerky vibration levelAnd gear ratioByAccelerator opening threshold value setting means for setting an accelerator opening threshold value by a larger value as the vehicle speed is higher and the transmission ratio is higher,
Coast lockup stateIn the case where the detected accelerator opening is equal to or greater than the set accelerator opening threshold during the set time from the start of accelerator depression,Temporary lock-up release means for temporarily releasing lock-up,
Is provided.
[0014]
Function and Effect of the Invention
In the invention according to claim 1 of the present invention, the lock-up control means engages the lock-up clutch of the torque converter even during coasting of the vehicle due to release of the accelerator. AndAccelerator opening threshold setting meansThe vehicle speed at the start of accelerator depression correlated with the rattling vibration levelAnd gear ratioByThe accelerator opening threshold value is set to a larger value as the vehicle speed is higher and the gear ratio is higher.In the temporary lockup release means, the coast lockup stateIn the case where the detected accelerator opening is equal to or greater than the set accelerator opening threshold during the set time from the start of accelerator depression,Lockup is temporarily released.
[0015]
That is, in the low vehicle speed range where the rattling vibration is likely to occur when the accelerator is depressed, or in the low gear ratio range,Accelerator opening thresholdWill be set to a low value, and if you suddenly operate the accelerator from the coast lockup state,Accelerator openingExceeds the threshold value, the lock-up is temporarily released, the torque fluctuation is absorbed by the torque converter by the fluid coupling function, and the rattling vibration is suppressed.
[0016]
On the other hand, in the high vehicle speed region where the rattling vibration is hardly generated, or the vibration level is small even if it is generated, or in the high gear ratio range,Accelerator opening thresholdIs set to a high value, and unless the accelerator is depressed quickly from the coast lockup state, the pedaling speed is fast enough.Accelerator openingDoes not exceed the threshold value, lock-up is maintained and fuel efficiency is improved.
[0017]
Thus, the lock-up releaseAccelerator opening thresholdThe parameters that correlate with the level of the vibration(Vehicle speed and transmission ratio), It is possible to achieve both the suppression of the rattling vibration and the improvement of fuel efficiency.
[0018]
Also, accelerator opening threshold value setting meansThe vehicle speed at the start of accelerator depressionAnd gear ratioThe lower the jerky vibration level estimated by, the harder it is to release lockup temporarilyAccelerator opening thresholdIs set to
[0019]
in this way,Accelerator opening thresholdIs not a step-by-step setting, but a parameter that is correlated with the level of jerky vibration(Vehicle speed and transmission ratio)By setting according to the jerky vibration level estimated by the above, regardless of the magnitude of the estimated jerky vibration level, it is possible to achieve both the suppression of the jerky vibration and the improvement of fuel efficiency.
[0020]
further,In the temporary lock-up release means, in the coast lock-up state, if the detected accelerator opening becomes equal to or more than the set accelerator opening threshold during the set time from the start of accelerator depression, the vehicle is temporarily locked. Up is released.
[0021]
That is, the accelerator stepping speed can be calculated from the amount of change in the accelerator opening per sampling period. However, if the sampling period is shortened, the calculation error increases, and if the sampling period is increased, the speed determination is delayed.
[0022]
On the other hand, the determination time of the accelerator depressing operation is determined in advance, and when the detected value of the accelerator opening at the time when the determination time has elapsed is equal to or greater than the accelerator opening threshold value, it is assumed that the accelerator is rapidly depressed. The speed comparison is performed substantially by comparing the detected accelerator opening without calculating the speed by the differential operation, and an effective lockup release condition without a calculation error or delay can be determined.
[0023]
BEST MODE FOR CARRYING OUT THE INVENTION
A lock-up control device for an automatic transmission according to the present invention will be described in detail with reference to the drawings.
[0024]
[Configuration of transmission unit and transmission control device of continuously variable transmission]
1 and 2 show a toroidal-type continuously variable transmission provided with a lock-up control device for an automatic transmission according to the present invention. FIG. 1 is a longitudinal sectional side view showing a transmission unit of the toroidal-type continuously variable transmission. FIG. 3 is a diagram illustrating a shift control device of the toroidal-type continuously variable transmission.
[0025]
First, a transmission unit which is a main part of a toroidal type continuously variable transmission will be described with reference to FIG. This transmission unit includes an input shaft 20 through which rotation from an engine (not shown) is transmitted via a torque converter with a lock-up clutch. As shown in FIG. 1, the input shaft 20 shifts its end far from the engine. It is rotatably supported in a machine case 21 via a bearing 22, and the center is rotatably supported in a middle wall 23 of the transmission case 21 via a bearing 24 and a hollow output shaft 25.
[0026]
The input shaft 20 supports the input cone disc 1, the hollow output shaft 25 supports the output cone disc 2, and the input and output cone discs 1 and 2 have their toroidal curved surfaces 1a and 2a facing each other. Coaxial arrangement.
[0027]
A pair of power rollers 3, 3 disposed on both sides of the input shaft 20 with the input shaft 20 interposed therebetween are interposed between the opposed toroid curved surfaces 1a, 2a of the input / output cone disks 1, 2, and these power rollers 3, 3 The following configuration is adopted in order to clamp the pressure between the input and output cone disks 1 and 2.
[0028]
That is, a loading nut 26 is screwed into the end of the input shaft 20 on the bearing 22 side, the cam disk 27 is prevented from falling off by the loading nut 26 and is rotationally engaged on the input shaft 20, and the toroid of the input cone disk 1 A loading cam 28 is interposed between the end surface far from the curved surface 1a, and rotation from the input shaft 20 to the cam disk 27 is transmitted to the input cone disk 1 via the loading cam 28.
[0029]
Here, the rotation of the input cone disk 1 is transmitted to the output cone disk 2 via the rotation of the two power rollers 3, 3, and during this transmission, the loading cam 28 generates a thrust proportional to the transmission torque, and , 3 are narrowed between the input and output cone disks 1, 2 to enable the power transmission.
[0030]
The output cone disk 2 is wedge-fitted to an output shaft 25, and an output gear 29 is fitted on the output shaft 25 so as to rotate integrally.
[0031]
The output shaft 25 is further rotatably supported in an end cover 31 of the transmission case 21 via a radial / thrust bearing 30, and the input shaft 20 is separately provided in the end cover 31 via a radial / thrust bearing 32. It is rotatably supported. Here, the radial and thrust bearings 30 and 32 are butted so as not to approach each other at the start of the spacer 33, and the corresponding output gear 29 has an axis relative to the input shaft 20 so that relative displacement in a direction away from each other is impossible. Make contact in the direction.
[0032]
With the above configuration, the thrust acting between the input and output cone disks 1 and 2 by the loading cam 28 becomes an internal force that sandwiches the spacer 33 and does not act on the transmission case 21.
[0033]
As shown in FIG. 2, the power rollers 3, 3 are rotatably supported by trunnions 41, 41. Each of the trunnions 41, 41 is rotatably supported at both ends of an upper link 43 by a spherical joint 42. The lower end is rotatably and swingably connected to both ends of a lower link 45 by a spherical joint 44.
[0034]
The upper link 43 and the lower link 45 are supported at the center thereof by the spherical joints 46 and 47 in the transmission case 21 so as to be able to swing up and down, and the two trunnions 41 and 41 are vertically moved synchronously in opposite directions. To get.
[0035]
A shift control device that performs a shift by vertically moving the two trunnions 41 in synchronization with each other in the above-described manner will be described with reference to FIG.
[0036]
Each of the trunnions 41, 41 is provided with a piston 6, 6 for individually moving the trunnions 41 in the vertical direction, and defines upper chambers 51, 52 and lower chambers 53, 54 on both sides of the pistons 6, 6, respectively. . To control the strokes of the pistons 6 and 6 in opposite directions, a shift control valve 5 is provided.
[0037]
Here, the shift control valve 5 slidably fits the spool-type inner valve element 5a and the sleeve-type outer valve element 5b so that the outer valve element 5b can slide on the valve case 5c. It is configured by fitting.
[0038]
The speed change control valve 5 has an input port 5d connected to a pressure source 55, one communication port 5e connected to the piston chambers 51 and 54, and the other communication port 5f connected to pistons 52 and 53, respectively.
[0039]
Then, the inner valve body 5a cooperates with the cam surface of the precess cam 7 fixed to the lower end of the one trunnion 41 via a bell crank type shift lever 8, and the outer valve body 5b is used as a stepping motor 4 as a shift actuator. Then, drive engagement is performed in a rack and pinion type.
[0040]
The operation command of the shift control valve 5 is given by the step motor 4 responsive to the actuator drive position command Asstep (step position command) as a stroke to the outer valve body 5b via a rack and pinion.
[0041]
With this operation command, when the outer valve body 5b of the shift control valve 5 is displaced from the neutral position relative to the inner valve body 5a to, for example, the position of FIG. Is supplied to the chambers 52 and 53, the other chambers 51 and 54 are drained, and the outer valve body 5b of the transmission control valve 5 is relatively moved with respect to the inner valve body 5a. When the shift control valve 5 is opened by being displaced in the opposite direction from the neutral position, the fluid pressure from the pressure source 55 is supplied to the chambers 51 and 54, while the other chambers 52 and 53 are drained and the two trunnions 41 and 41 are discharged. Is displaced in the corresponding vertical direction in the figure by the fluid pressure via the pistons 6 and 6 in opposite directions.
[0042]
As a result, the two power rollers 3, 3 are rotated₁Is the rotation axis O of the input and output cone disks 1 and 2.₂Is offset from the illustrated position (offset amount y) intersecting with the power rollers 3, 3 due to the nuclear offset, the power rollers 3, 3 are self-rotating axis O due to the swinging component from the input / output cone disks 1, 2.₁The swing axis O that goes straight to₃(Inclination angle φ) to perform continuously variable transmission.
[0043]
During such a shift, the precess cam 7 coupled to the lower end of the one trunnion 41 controls the above-described vertical movement (offset amount y) and the tilt angle φ of the trunnion 41 and the power roller 3 via the shift link 8. Feedback is mechanically fed back to the inner valve body 5a of the valve 5 as indicated by x.
[0044]
When the speed ratio command value corresponding to the actuator drive position command Asstep to the step motor 4 is achieved by the stepless speed change, the mechanical feedback through the precess cam 7 causes the inner valve of the speed change control valve 5 to move. The body 5a is returned to the initial neutral position relative to the outer valve body 5b, and at the same time, both power rollers 3, 3 are rotated by the rotation axis O.₁Is the rotation axis 0 of the input and output cone disks 1 and 2.₂By returning to the illustrated position intersecting with the above, it is possible to maintain the state of achievement of the above-mentioned speed ratio command value.
[0045]
Since the aim of the control is to make the power roller tilt angle φ a value corresponding to the gear ratio command value, the precess cam 7 basically has to feed back only the power roller tilt angle φ. Here, the reason why the power roller offset amount y is also fed back is to avoid a hunting phenomenon of the shift control by giving a damping effect of preventing the shift control from becoming oscillating.
[0046]
The actuator drive position command Asstep to the step motor 4 is set by the controller 61.
[0047]
For this purpose, as shown in FIG. 2, a signal from a throttle opening sensor 62 for detecting an engine throttle opening TVO, a signal from a vehicle speed sensor 63 for detecting a vehicle speed VSP, and a rotation speed of the input cone disk 1 are provided to the controller 61 as shown in FIG. A signal from an input rotation sensor 64 for detecting Ni (or an engine rotation speed Ne), a signal from an output rotation sensor 65 for detecting a rotation speed No of the output cone disk 2, and an oil temperature for detecting a transmission working oil temperature TMP. The signal from the sensor 66, the line pressure P from the hydraulic pressure source 55_L(Usually the line pressure P_LIs detected by an internal signal of the controller 61 because the controller 61 controls the controller 61), a signal from a line pressure sensor 67, a signal from an engine rotation sensor 68 for detecting the engine speed Ne, and a signal about range information from the inhibitor switch 60. , A signal about UP / DOWN information from the UP / DOWN switch 69, a selection mode signal from the mode selection switch 70, a torque down permission signal from the engine control device 310, and an ABS control from the anti-skid control device (ABS) 320 A signal, a TCS control signal from the traction control device (TCS) 330, and a constant speed running operation signal from the constant speed running device 340 are input.
[0048]
The controller 61 sets the actuator drive position command Asstep (shift command value) to the step motor 4 by the following calculation based on the above various input information.
[0049]
[Controller configuration]
In the present embodiment, the controller 61 is configured as shown in FIG.
[0050]
The shift map selection unit 71 selects a shift map in accordance with various conditions such as the oil temperature TMP detected by the sensor 66 in FIG. 2 and whether or not the exhaust purifying catalyst is being activated.
[0051]
A description will be given of the case where the shift map selected in this way is, for example, as shown in FIG. 4. The reaching input rotation speed calculating section 72 calculates the throttle opening TVO and the throttle opening TVO detected by the sensors 62 and 63 in FIG. From the vehicle speed VSP, based on a shift map corresponding to the shift diagram in the same figure, a reached input speed Ni to be a steady target input speed in the current driving state.^*Search for and ask.
[0052]
The reaching gear ratio calculating section 73 calculates the reaching input rotational speed Ni.^*Is divided by the transmission output rotation speed No detected by the sensor 65 in FIG.^*Attained gear ratio i which is a steady target gear ratio corresponding to^*Ask for.
[0053]
The shift time constant calculator 74 includes a selection range (forward normal travel range D, forward sports travel range Ds), a vehicle speed VSP, a throttle opening TVO, an engine speed Ne, an accelerator pedal operation speed, and a torque down control device (not shown). ), The speed reduction according to various conditions such as a torque reduction amount signal, a torque reduction permission signal, an anti-skid control signal, a traction control signal, a constant speed traveling signal, and a speed ratio deviation RtoERR from a target speed ratio Ratio0 described later. A first speed change time constant Tg1 and a second speed change time constant Tg2 for the control are set, and the ultimate speed ratio i^*And a deviation Eip between the target gear ratio Ratio0 and the target gear ratio Ratio0.
[0054]
Here, the first speed change time constant Tg1 and the second speed change time constant Tg2, which are set to correspond to the secondary delay system of the toroidal type continuously variable transmission, are equal to the ultimate speed ratio i.^*The target speed ratio calculating unit 75 sets the shift speed by setting the response of the speed change to the target speed ratio.^*Are calculated at the transitional time and moment, respectively, for realizing with the shift response determined by the first shift time constant Tg1 and the second shift time constant Tg2, and only the target shift ratio Ratio0 is calculated. Is output.
[0055]
The input torque calculation unit 76 obtains the transmission input torque Ti by a known method, first obtains the engine output torque from the throttle opening TVO and the engine speed Ne, and then obtains the input / output speed (Ne, Ni), the torque ratio t of the torque converter is obtained from the speed ratio, and finally the engine output torque is multiplied by the torque ratio t to calculate the transmission input torque Ti.
[0056]
The torque-shift-compensated transmission ratio calculation unit 77 uses the transient target transmission ratio Ratio0 and the transmission input torque Ti to remove a torque shift (incorrect transmission ratio) peculiar to a toroidal-type continuously variable transmission. A compensation speed ratio TSrto is calculated.
[0057]
Here, a supplementary explanation of the torque shift of the toroidal type continuously variable transmission is as follows. During transmission of the toroidal type continuously variable transmission, the power rollers 3, 3 are connected between the input and output cone disks 1, 2 as described above. The clamping causes a deformation of the trunnion 41, which changes the position of the precess cam 7 at the lower end of the trunnion, causing a change in the path length of the mechanical feedback system composed of the precess cam 7 and the speed change link 8, thereby causing The torque shift is generated.
[0058]
Therefore, the torque shift of the toroidal-type continuously variable transmission differs depending on the target speed ratio Ratio0 and the transmission input torque Ti, and the torque shift compensation speed ratio calculation unit 77 searches the torque shift compensation speed ratio TSrto from these two-dimensional maps. Ask by.
[0059]
The actual speed ratio calculating unit 78 calculates the actual speed ratio Ratio by dividing the transmission input speed Ni by the transmission output speed No detected by the sensor 65 in FIG. The speed ratio deviation calculating section 79 subtracts the actual speed ratio from the target speed ratio Ratio0 to obtain a speed ratio deviation RtoERR (= Ratio0-Ratio) between the two.
[0060]
The first feedback (FB) gain calculator 80 calculates a gear ratio feedback correction amount by well-known PID control (P is proportional control, I is integration control, and D is differential control) according to the gear ratio deviation RtoERR. Among the feedback gains of the respective controls, a first proportional control feedback gain fbpDATA1, an integral control feedback gain fbiDATA1, and a differential control feedback gain to be set according to the transmission input rotation speed Ni and the vehicle speed VSP. fbdDATA1 is obtained.
[0061]
These first feedback gains fbpDATA1, fbiDATA1 and fbdDATA1 are previously determined as a two-dimensional map of the transmission input rotation speed Ni and the vehicle speed VSP, and based on this map, the transmission input rotation speed Ni and the vehicle speed VSP are used to determine the first feedback gain fbpDATA1, fbiDATA1 and fbdDATA1. Shall be sought.
[0062]
The second feedback (FB) gain calculator 81 calculates the transmission working oil temperature TMP and the line pressure P among the feedback gains used when calculating the speed ratio feedback correction amount by the PID control._L, A second proportional control feedback gain fbpDATA2, an integral control feedback gain fbiDATA2, and a differential control feedback gain fbdDATA2 to be set in accordance with the above.
[0063]
These second feedback gains fbpDATA2, fbiDATA2, fbdDATA2 are determined by the hydraulic oil temperature TMP and the line pressure PMP._LIs determined in advance as a two-dimensional map of the hydraulic oil temperature TMP and the line pressure P based on this map._LFrom the search.
[0064]
The feedback gain calculation unit 83 multiplies the first feedback gain and the second feedback gain by the corresponding feedback gains, and obtains a proportional control feedback gain fbpDATA (= fbpDATA1 × fbpDATA2) and an integral control feedback gain fbiDATA ( = FbiDATA1 × fbiDATA2) and the differential control feedback gain fbdDATA (= fbdDATA1 × fbdDATA2).
[0065]
The PID control unit 84 uses the feedback gain obtained as described above to calculate the gear ratio feedback correction amount FBrto by the PID control according to the gear ratio deviation RtoERR,
The speed ratio feedback correction amount by the proportional control is obtained by RtoERR × fbpDATA,
Next, the gear ratio feedback correction amount by the integral control is obtained by ∫RtoERR × fbiDATA,
Further, the speed ratio feedback correction amount by the differential control is obtained by (d / dt) RtoERR × fbdDATA,
Finally, the sum of the three is set as a gear ratio feedback correction amount FBrto (= RtoERR × fbpDATA + ∫RtoERR × fbiDATA + (d / dt) RtoERR × fbdDATA) by PID control.
[0066]
The target gear ratio corrector 85 corrects the target gear ratio Ratio0 by the torque shift compensation gear ratio TSrto and the gear ratio feedback correction amount FBrto to obtain a corrected target gear ratio DsrRTO (= Ratio0 + TSrto + FBrto). The target step number (actuator target drive position) calculation unit 86 obtains the target step number (actuator target drive position) DsrSTP of the step motor (actuator) 4 for realizing the corrected target gear ratio DsrRTO by searching a map.
[0067]
The step motor drive position command calculation unit 87 determines that the step motor 4 is capable of setting the target step number DsrSTP during one control cycle even at the limit drive speed of the step motor 4 set by the step motor drive speed setting unit 88 based on the transmission operating oil temperature TMP and the like. When the step motor 4 cannot be displaced, the achievable limit position achievable at the above limit drive speed of the step motor 4 is set as the drive position command Astep to the step motor 4, and the step motor 4 sets the target step number DsrSTP during one control cycle. When it can be displaced, the target step number DsrSTP is directly used as the drive position command Astep to the step motor 4.
[0068]
Accordingly, the drive position command Asstep can always be regarded as the actual drive position of the step motor 4.
[0069]
The step motor 4 is displaced in the direction and the position corresponding to the drive position command Astep to cause the outer valve body 5b of the speed change control valve 5 to stroke through the rack and pinion, as described above for the toroidal type continuously variable transmission. The speed can be changed as desired.
[0070]
When a speed ratio command value corresponding to the drive position command Asstep is achieved by this shift, mechanical feedback via the precess cam 7 causes the inner valve element 5a of the shift control valve 5 to move relative to the outer split element 5b. At the same time, the power rollers 3 and 3 are simultaneously rotated to the rotation axis 0.₁Is the rotation axis 0 of the input and output cone disks 1 and 2.₂By returning to the illustrated position intersecting with the above, it is possible to maintain the state of achievement of the above-mentioned speed ratio command value.
[0071]
In the present embodiment, a step motor follow-up determination section 89 is additionally provided.
[0072]
The step motor follow-up determination section 89 determines whether or not the step motor 4 can follow the target step number (actuator target drive position) DsrSTP corresponding to the corrected target gear ratio DsrRTO as follows.
[0073]
That is, the determination unit 89 first obtains a step number deviation (actuator driving position deviation) △ STP between a target step number (actuator target driving position) DsrSTP and a driving position command Asstep that can be regarded as an actual driving position.
[0074]
The determination unit 89 determines the step number deviation (actuator drive) in which the step motor 4 cannot be canceled within one control cycle even at the limit drive speed of the step motor 4 set as described above by the step motor drive speed setting unit 88. Lower limit of position deviation)） STP_LIMStep number deviation (actuator drive position deviation) △ STP is smaller than (△ STP <△ STP_LIM), It is determined that the step motor 4 can follow the target step number (actuator target drive position) DsrSTP corresponding to the corrected target gear ratio DsrRTO,
Conversely, △ STP ≧ △ STP_LIM, It is determined that the step motor 4 cannot follow the target step number (actuator target drive position) DsrSTP.
[0075]
If the determination unit 89 determines that the step motor 4 can follow the target step number (actuator target drive position) DsrSTP corresponding to the corrected target speed ratio DsrRTO, the PID control unit 84 determines the PID as described above. The calculation of the gear ratio feedback correction amount FBrto by the control is continued.
[0076]
In this way, when it is determined that the step motor 4 cannot follow the target step number (actuator target drive position) DsrSTP, the gear ratio feedback correction amount 積分 RtoERR × fbiDATA by the integral control is held at the value at the time of the determination. To the PID control unit 84 to perform the operation.
[0077]
Further, in the present embodiment, when the step motor drive position command calculation unit 87 cannot displace the step motor 4 to the target step number DsrSTP during one control cycle even at the limit drive speed of the step motor 4, the step motor 4 The achievable limit position achievable at the drive speed is set as a drive position command Astep to the step motor 4, and this drive position command Astep is used as an actual drive position of the step motor 4 by the determination unit 89 for the step motor follow-up determination. I decided to contribute
The actual drive position of the step motor 4 necessary for making such a follow-up determination is detected by the drive position command Astep from the transmission control device to the step motor 4. This can be performed at low cost without relying on the actual measurement of the actual driving position.
[0078]
Further, in the present embodiment, the step motor follow-up possibility determining section 89 determines the step number deviation (actuator drive position deviation) between the target step number (actuator target drive position) DsrSTP and the actual drive position (drive position command) Asstep. ΔSTF is a tracking determination standard deviation determined for each limit driving speed of the step motor 4 ΔSTP_LIMLess than ($ STP <$ STP_LIM), It is determined that the step motor 4 can follow the target step number (actuator target drive position) DsrSTP corresponding to the corrected target gear ratio DsrRTO, and conversely, △ STP ≧ △ STP_LIM, It is determined that the step motor 4 cannot follow the target step number (actuator target drive position) DsrSTP.
It is possible to reliably determine that the stepping motor 4 can follow, regardless of the limit driving speed of the stepping motor 4 that changes variously depending on the oil temperature TMP or the like.
[0079]
[About shift control]
When the controller 61 of FIG. 2 is constituted by a microcomputer, the shift control described with reference to FIG. 3 is executed by the program of FIG.
[0080]
FIG. 5 shows the entire shift control, and this routine is executed, for example, every 10 ms. First, in step 91, the shift time constant calculation unit 74 (FIG. 3) inputs the vehicle speed VSP detected by the vehicle speed sensor 63 (FIG. 2), the engine speed Ne detected by the engine rotation sensor 68 (FIG. 2), and inputs. The transmission input rotation speed Ni detected by the rotation sensor 64 (FIG. 2), the throttle opening TVO detected by the throttle opening sensor 62 (FIG. 2), and range information (automatic transmission) from the inhibitor switch 60 (FIG. 2). (D) range, sports running (S) range, etc.) are read.
[0081]
Next, in step 92, the reached input speed calculating unit 72 (FIG. 3) calculates the actual speed ratio Ratio by dividing the input speed Ni by the transmission output speed No. Next, at step 93, the target input rotational speed Ni is calculated based on the throttle opening TVO and the vehicle speed VSP based on the shift map shown in FIG.^*Search for and ask.
[0082]
Next, at step 94 as the reaching speed ratio setting means, the reaching speed ratio calculating section 73 (FIG. 3) determines the reaching input rotational speed Ni.^*Is divided by the transmission output speed No to obtain the attained gear ratio i^*Is calculated. Next, in step 95 as the deviation calculating means, the shift time constant calculating unit 74 (FIG. 3) determines the attained speed ratio i^*Then, the deviation Eip is calculated by subtracting the target gear ratio Ratio0 calculated in the previous routine (this is calculated in a later step 99).
[0083]
Next, at step 96, it is determined whether or not there is a stepped shift by mode switching and manual shift (hereinafter, referred to as "switch shift"). Specifically, in response to a selection mode signal from the mode selection switch 70 (FIG. 2), the presence or absence of switching between the power mode and the snow mode is detected, and a manual range signal is output from the inhibitor switch 60 (FIG. 2). At the same time, it is determined whether or not a signal regarding UP / DOWN information has been detected from the UP / DOWN switch 69 (FIG. 2). Next, in steps 97 and 98 as the mode setting means and in step 99 as the target gear ratio setting means, the shift time constant calculating section 74 (FIG. 3) sets the time constant calculation mode, Tg1 and Tg2, a target speed ratio Ratio0 and an intermediate speed ratio Ratio00 are calculated, respectively.
[0084]
Thereafter, in step 100, the torque shift compensation speed ratio calculation unit 77 (FIG. 3) calculates the torque shift compensation speed ratio TSrto from the map relating to the target speed ratio Ratio0 and the transmission input torque Ti. Next, in step 101, the PID control unit 84 (FIG. 3) calculates the gear ratio feedback correction amount FBrto by PID control. Next, in step 102, the target gear ratio correction unit 85 (FIG. 3) calculates the corrected target gear ratio DsrRTO by adding the torque shift compensation gear ratio TSrto and the gear ratio feedback correction amount FBrto to the target gear ratio Ratio0. Next, in step 103, a drive position command Asstep to the step motor 4 (FIG. 2) is calculated, and this routine ends.
[0085]
[Lockup control processing]
FIG. 6A is an overall flowchart showing a lockup determination process in the lockup control program.
[0086]
In step 104, the sudden depression lock-up prohibition determination processing shown in FIG. 7 is performed, and the routine proceeds to step 105.
[0087]
In step 105, it is determined whether the result of the determination in step 104 is lock-up permission or lock-up prohibition. If lock-up is permitted, the process proceeds to step 106;
[0088]
In step 106, other prohibition conditions, such as low oil temperature, ABS operation, TCS operation, reverse, low input rotation, etc., are determined, and the routine proceeds to step 107.
[0089]
In step 107, it is determined whether or not lock-up is prohibited because the prohibition condition in step 106 is satisfied. If NO, proceed to step 108, and if YES, proceed to step 111.
[0090]
In step 108, the lockup area is determined based on the vehicle speed VSP, and the process proceeds to step 109. Here, as shown in FIG. 6B, the lockup region is set to a region where the vehicle speed VSP is equal to or higher than the set vehicle speed (for example, 20 km / h) regardless of the throttle opening (0% to 100%). ing. Therefore, even if the vehicle speed condition is satisfied during the coasting due to the accelerator release, the vehicle is locked up.
[0091]
In step 109, it is determined whether or not the determination in step 1208 is the lock-up area. If YES, the process proceeds to step 110, and if NO, the process proceeds to step 111.
[0092]
In step 110, a lockup state is established in which the lockup clutch is engaged.
[0093]
In step 111, a torque converter state for releasing the lock-up clutch is set.
[0094]
FIG. 7 is a flowchart showing a sudden depression lock-up prohibition determination process in the lock-up control program.
[0095]
In step 112, it is determined whether or not the result of the sudden step lock-up release determination processing shown in FIG. 8 is a sudden step or a step other than a sudden step. If the step is a sudden step, the process proceeds to step 115; .
[0096]
In step 113, the lock-up state is determined. When it is determined that the vehicle is in the torque converter state, the process proceeds to step 117.
[0097]
In step 114, a sudden depression lock-up release determination process shown in FIG. 8 is performed.
[0098]
In step 115, it is determined whether or not the lock-up prohibition timer value RELUTIM for continuing lock-up prohibition from the sudden depression determination is RELUTIM = 0, that is, whether or not the lock-up prohibition time has elapsed. If yes, go to step 116. The lock-up prohibition timer value RELUTIM is set in advance in a control constant table.
[0099]
In step 116, when it is determined in step 115 that the lock-up prohibition time has elapsed, it is determined that the operation is other than sudden depression, and the process proceeds to step 117.
[0100]
In step 117, it is determined that the lockup is permitted.
[0101]
In step 118, if it is determined in step 115 that the lock-up prohibition time has not elapsed, the lock-up prohibition timer value RELUTIM is subtracted from RELUTIM = RELUTIM−1, and the routine proceeds to step 119.
[0102]
In step 119, it is determined that lock-up is prohibited.
[0103]
FIG. 8 is a flowchart showing a sudden depression lock-up release determination process in the lock-up control program.
[0104]
In step 120, a control constant table corresponding to the range and the traveling mode is searched, and a low vehicle speed threshold value rpaclofl and a high vehicle speed threshold value rpaclofvh and an initial depression time tvotim for judging a sudden depression after the vehicle has become idle OFF are determined. Can be
[0105]
In step 121, it is determined whether or not the vehicle is in an idle state based on an idle switch signal. When the switch is ON, the process proceeds to step 122, and when the switch is OFF, the process proceeds to step.
[0106]
In step 122, if it is determined in step 121 that the vehicle is in the idle state, the timer value Timer is set to Timer = tvotim, and the process proceeds to step 123.
[0107]
In step 123, it is determined that the operation is other than the sudden depression for permitting the lockup.
[0108]
In step 124, if it is determined in step 121 that the idle is OFF, the timer value Timer is decremented by Timer = Timer−1, and the routine proceeds to step 125.
[0109]
In step 125, it is determined whether or not the vehicle speed VSP is within a range not less than the low vehicle speed threshold value rpaclofl and less than the high vehicle speed threshold value rpaclohvh. If the vehicle speed condition is not satisfied, the process proceeds to step 123. Proceed to step 126. Here, a low vehicle speed region below the low vehicle speed threshold value rpacloflvl indicates a non-lockup region, and a high vehicle speed region above the high vehicle speed threshold value rpaclofvh indicates a region where no rattling vibration occurs.
[0110]
In step 126, when the vehicle speed condition is satisfied in step 125, it is determined whether or not the timer value Timer is Timer = 0, that is, whether or not the step-on initial time for judging a sudden step has passed. If NO, step 127 is performed. The process proceeds to step 130 if YES.
[0111]
In step 127, a table is selected from the range and the travel mode, and based on the vehicle speed VSP, the throttle opening threshold value iftvo is set to a larger value as the vehicle speed VSP is higher and the speed ratio is higher. (Corresponding to the accelerator opening threshold value) is calculated, and the routine proceeds to step 128.(Corresponds to accelerator opening threshold setting means). The throttle opening threshold value iftvo is given by three values of low (low), mid (middle), and hi (high) depending on the vehicle speed VSP and the range position (gear ratio). The value may be given by any number of steps as long as the value has two or more steps, or may be given by a finer stepless value.
[0112]
In step 128, it is determined whether or not the current throttle opening TvoSEN (corresponding to the accelerator opening) detected by the throttle opening sensor 62 is equal to or greater than the throttle opening threshold iofvo determined in step 127. If yes, go to step 129; if no, go to step 130.
[0113]
In step 129, the accelerator operation condition in step 128 is satisfied, so that it is determined that the lock-up is forcibly depressed.
[0114]
In step 130, when it is determined in step 126 that the initial depression time has elapsed, or when the accelerator operation condition is not satisfied in step 128, the previous determination is retained.
[0115]
[Lock-up control action]
First, in the case of a continuously variable transmission, since the gear ratio can be continuously changed in a lock-up state, lockup can be performed from a low speed as compared with a stepped automatic transmission. If the vehicle speed is in the lock-up region shown in FIG. 6B, the flow proceeds from step 108 to step 109 to step 110 in FIG. The clutch is engaged. However, when the accelerator is depressed suddenly from the coast lockup state and it is determined that the accelerator is depressed rapidly, the flow proceeds to step 112 → step 115 → step 118 → step 119 in the flowchart of FIG. The lock-up is temporarily released for the time set by the lock-up prohibition timer value RELUTIM for the purpose of suppressing the rattling vibration.
[0116]
Here, the determination of the sudden depression operation of the accelerator is made in step 127 of the flowchart of FIG. 8 based on the vehicle speed VSP and the gear ratio at the start of accelerator depression, which are correlated with the rattling vibration level, as the vehicle speed VSP becomes higher, and The throttle opening threshold value iftvo is calculated based on a larger value as the transmission ratio becomes higher. In step 128, the throttle opening TvoSEN detected by the throttle opening sensor 62 at that time is set to a throttle opening threshold. It is determined whether or not the value is equal to or greater than the value iftvo. If the determination is YES, the process proceeds to step 129, where it is determined that the lock-up is abrupt depression.
[0117]
That is, in a low vehicle speed range or a low gear ratio range where rattling vibration is likely to occur when the accelerator is depressed, the throttle opening threshold value iofvo is set to a low value, and the accelerator from the coast lockup state is rapidly depressed. When operated, the throttle opening TvoSEN from the start of accelerator depression is determined to be a sudden depression exceeding the throttle opening threshold value iofvo before the initial depression time tvotim for judging sudden depression, and is temporarily determined. The lock-up is released, the torque fluctuation is absorbed by the torque converter by the fluid coupling function, and the rattling vibration is suppressed.
[0118]
On the other hand, the throttle opening threshold value iftvo is set to a high value in a high vehicle speed region or a high gear ratio region where the rattling vibration is not likely to occur or the vibration level is small even if the rattling vibration occurs. The throttle opening threshold TvoSEN from the start of the accelerator depression until the initial depression time tvotim for judging the sudden depression unless the depression speed is high enough even if the accelerator is suddenly depressed from the up state. The value does not exceed iftvo, lock-up is maintained, and fuel efficiency is improved.
[0119]
As described above, by switching the throttle opening threshold value iftvo for unlocking by the parameters (vehicle speed and gear ratio) correlated with the level of the rattling vibration, it is possible to suppress the occurrence of the rattling vibration and to improve the fuel efficiency at the same time. Can be planned.
[0120]
In step 127, the throttle opening threshold value iftvo is set such that the lower the jerking vibration level estimated from the vehicle speed VSP and the range position (gear ratio) at the start of depressing the accelerator, the more difficult it is to temporarily release lockup. Therefore, regardless of the estimated level of the jiggle vibration, it is possible to achieve both suppression of the jiggle vibration and improvement in fuel efficiency.
[0121]
Further, in step 128, in the coast lockup state, the throttle opening TvoSEN from the start of accelerator depression exceeds the throttle opening threshold value iftvo until the initial depression time tvotim for judging sudden depression. Is determined, and the lock-up is temporarily released. Therefore, without calculating the speed by the differential operation of the throttle opening, the detected throttle opening TvoSEN is compared with the throttle opening threshold iofvo. The speed comparison is performed substantially, and an effective lock-up release condition without a calculation error or delay can be determined.
[0122]
That is, the accelerator stepping speed can be calculated from the amount of change in the accelerator opening per sampling period. However, if the sampling period is shortened, the calculation error increases, and if the sampling period is increased, the speed determination is delayed.
[0123]
The present invention is not limited to the above embodiment, and many modifications and variations are possible.
[0124]
For example, in the above-described embodiment, an example in which the lockup control device for an automatic transmission according to the present invention is applied to a toroidal-type continuously variable transmission has been described. However, the lock-up control device may be applied to a V-belt-type continuously variable transmission. Further, the present invention can be applied to a stepped automatic transmission that employs coast lockup.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional side view of a toroidal type continuously variable transmission including a lockup control device for an automatic transmission according to the present invention.
FIG. 2 is a vertical sectional front view showing the toroidal-type continuously variable transmission shown in FIG. 1 together with a shift control system thereof.
FIG. 3 is a functional block diagram of a shift control executed by a controller of FIG. 2;
FIG. 4 is a shift diagram illustrating a shift pattern of the continuously variable transmission.
FIG. 5 is a flowchart showing the entire shift control program of the automatic transmission lock-up control device according to the present invention.
FIG. 6A is an overall flowchart showing lockup determination processing in a lockup control program, and FIG. 6B is a lockup area characteristic diagram.
FIG. 7 is a flowchart showing a sudden depression lock-up prohibition determination process in the lock-up control program.
FIG. 8 is a flowchart showing a sudden depression lock-up release determination process in the lock-up control program.
[Explanation of symbols]
1 input cone disk
2 output cone disk
3 Power roller
4 Step motor
5 Shift control valve
6 piston
7 Precess cam
8 Speed change link
20 input shaft
28 Loading cam
41 Trunnion
43 Upper Link
45 Lower Link
60 Inhibitor switch
61 Controller
62 Throttle opening sensor
63 Vehicle speed sensor
64 input rotation sensor
65 output rotation sensor
66 Oil temperature sensor
67 Line pressure sensor
68 Engine rotation sensor
69 UP / DOWN switch
70 Mode selection switch
71 Shift map selector
72 Arrival input rotation speed calculation unit
73 Achieved gear ratio calculator
74 Shift time constant calculator
75 Target gear ratio calculator
310 Engine control switch
320 Anti-skid control device
330 Traction control device
340 Constant speed traveling device

Claims (1)

A lock-up control device for an automatic transmission including a lock-up control unit that engages a lock-up clutch of a torque converter even during coasting of a vehicle (coast);
According to the vehicle speed and the gear ratio at the start of depressing the accelerator, which are correlated with the rattling vibration level, the accelerator that sets the accelerator opening threshold value with a larger value as the vehicle speed becomes higher and the gear ratio becomes higher. Opening threshold value setting means;
Temporary lock-up that temporarily releases lock-up when the detected accelerator opening exceeds the set accelerator opening threshold during the set time from the start of accelerator depression in the coast lock-up state Release means,
A lock-up control device for an automatic transmission, comprising:

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