JP4339565B2 - Shift control device for continuously variable transmission - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a transmission control device for a continuously variable transmission having a torque converter with a lock-up clutch.
[0002]
[Prior art]
As a continuously variable transmission used for a vehicle such as an automobile, there are a belt type and a toroidal type. A belt-type continuously variable transmission has an input-side primary pulley provided on an input shaft, an output-side secondary pulley provided on an output shaft, and a power transmission element such as a belt or a chain spanned between these pulleys. is doing. By changing the groove width of each pulley and changing the winding diameter of the power transmission element, the transmission gear ratio changes steplessly, and the rotation of the input shaft can be transmitted to the output shaft by controlling it to a predetermined rotational speed. it can.
[0003]
Such a speed change control device for a continuously variable transmission has a memory in which a normal speed change characteristic map is stored, and refers to the normal speed change characteristic map based on parameters indicating operating conditions such as throttle opening and vehicle speed. Thus, the target rotational speed of the primary pulley is set, and the follow-up control is performed so that the actual primary pulley rotational speed converges on the target rotational speed. For example, when the accelerator pedal is depressed to accelerate the vehicle speed, the target speed of the primary pulley is controlled so that the target speed ratio corresponding to the throttle opening, that is, the speed change line is obtained. As a result, the gear ratio is continuously controlled from low to overdrive, but the target speed of the primary pulley calculated based on the throttle opening and the vehicle speed is determined by considering the normal driving feeling. The target gear ratio is shifted to the overdrive side as the opening is smaller.
[0004]
On the other hand, in a vehicle in which a torque converter with a lock-up clutch is provided between the engine and the continuously variable transmission, when the vehicle speed exceeds a predetermined value, the lock-up clutch is engaged to make the engine a primary pulley. They are directly connected. Although it is preferable to engage the lockup clutch at a low vehicle speed as much as possible from the viewpoint of fuel efficiency, the engine speed decreases toward the shift line when the lockup clutch is engaged, so the acceleration of the vehicle speed decreases. It will be.
[0005]
[Problems to be solved by the invention]
In particular, the deviation between the engine rotational speed and the primary pulley rotational speed when the throttle opening is low, that is, in the state of a low shift line and the acceleration is enhanced under a low vehicle speed. Therefore, if the lock-up clutch is engaged at such a time from the viewpoint of emphasizing fuel efficiency, the engine speed is greatly reduced toward the shift line. When the engine rotational speed is reduced in this way, the acceleration of the vehicle is reduced, so that a feeling of being pulled in and a feeling of slippage are generated, driving feeling and running feeling are deteriorated, and a problem arises that the passenger feels uncomfortable.
[0006]
In order to prevent the occupant from feeling uncomfortable when the lock-up clutch is engaged, in the speed change control device disclosed in Japanese Patent Laid-Open No. 7-248056, the speed ratio is set smaller than the maximum speed ratio at the start, Shift control is performed so as to match the maximum gear ratio as the lock-up clutch is engaged. However, if the gear ratio is set smaller than the maximum gear ratio at the time of starting, the driving force of the engine cannot be sufficiently exerted at the time of starting when the driving force is required, and the starting acceleration performance is impaired.
[0007]
Further, in the shift control device disclosed in Japanese Patent Laid-Open No. 63-192629, it is based on map data during normal driving until a predetermined time elapses after the lockup clutch engagement command is output. Thus, the target rotational speed of the primary pulley is set, and after a predetermined time elapses, gear shift control is performed so as to decrease the target rotational speed, and the engine rotational speed is decreased during the lockup clutch engagement process. However, such a control method has a problem that start acceleration cannot be sufficiently ensured.
[0008]
Further, in the toroidal type continuously variable transmission disclosed in Japanese Patent Laid-Open No. 9-210166, a control signal is output to the transmission with a delay from the output of the engagement command to the lockup clutch, and the transmission ratio is Is controlled so as to shift the speed to the deceleration side before engagement of the lockup clutch, thereby preventing the occurrence of an engagement shock due to a response delay of the lockup clutch. However, since the gear ratio is changed after the engagement command is output, there is a problem that the start acceleration performance cannot be sufficiently ensured.
[0009]
An object of the present invention is to improve the start acceleration of a continuously variable transmission.
[0010]
[Means for Solving the Problems]
  The transmission control device for a continuously variable transmission according to the present invention includes a continuously variable transmission that continuously changes the rotation of an input-side rotating body via a power transmission element and transmits the rotation to an output-side rotating body, the engine, and the continuously variable transmission. A transmission control device for a continuously variable transmission including a torque converter with a lock-up clutch provided between the transmission and a target rotational speed of the input-side rotating body based on a parameter indicating an operating state. Normal transmission mode setting means for setting the speed of rotation, start acceleration mode determination means for determining when the vehicle starts acceleration,When the vehicle speed is not more than a predetermined value, the opening degree of the throttle valve is not less than a predetermined value, and the opening speed of the throttle valve is not less than a predetermined value and the start acceleration mode determining means determines the start acceleration mode, From the start of rear shiftUntil the lockup clutch is completely engaged, the amount of change in the rotational speed of the input side rotating body is lower than the target speed ratio in the normal speed change modeFrom the normal shift modeStart acceleration mode setting means to set large andWhen the vehicle speed is equal to or higher than the predetermined value, the throttle valve opening is larger than the predetermined value, and the opening speed of the throttle valve is higher than the predetermined value, the target gear ratio is set to a lower speed side than the start acceleration mode. Kickdown mode setting means to setIt is characterized by having.
[0011]
  In the transmission control device for a continuously variable transmission according to the present invention, the start acceleration mode determination means determines that the start acceleration mode is selected when the accelerator opening is equal to or greater than a predetermined value and the accelerator opening speed is equal to or greater than a predetermined value. It is characterized by doing.
[0012]
  The shift control device for a continuously variable transmission according to the present invention includes a start acceleration mode cancel determining unit that determines cancel of the start acceleration mode, and normal control when the cancel of the start acceleration mode is determined by the start acceleration mode cancel determining unit. Change the gear ratio change until the target gear ratio is reached.More than the gear ratio change amount in the normal gear shift modeAnd a target gear ratio change amount limiting means for limiting.
[0013]
  In the speed change control device for a continuously variable transmission according to the present invention, the start acceleration mode release determination means may determine the start acceleration mode when the opening of the throttle valve is equal to or smaller than a predetermined value and the opening continues for a predetermined time. It is characterized by determining release of.
[0014]
  In the transmission control device for a continuously variable transmission according to the present invention, the start acceleration mode release determination means cancels the start acceleration mode when the accelerator opening is equal to or less than a predetermined value and the opening continues for a predetermined time. It is characterized by determining.
[0015]
  The transmission control device for a continuously variable transmission according to the present invention includes a continuously variable transmission that continuously changes the rotation of an input-side rotating body via a power transmission element and transmits the rotation to an output-side rotating body, the engine, and the continuously variable transmission. A transmission control device for a continuously variable transmission including a torque converter with a lock-up clutch provided between the transmission and a target rotational speed of the input-side rotating body based on a parameter indicating an operating state. A normal transmission mode setting means for setting the speed change rotation, a start acceleration mode determination means for determining when the vehicle starts acceleration,When the vehicle speed is not more than a predetermined value, the opening degree of the throttle valve is not less than a predetermined value, and the opening speed of the throttle valve is not less than a predetermined value and the start acceleration mode determining means determines the start acceleration mode, From the start of rear shiftUntil the lockup clutch is completely engaged, the amount of change in the rotational speed of the input side rotating body is lower than the target speed ratio in the normal speed change modeFrom the normal shift modeStart acceleration mode setting means to set large andWhen the vehicle speed is equal to or higher than the predetermined value, the throttle valve opening is larger than the predetermined value, and the opening speed of the throttle valve is higher than the predetermined value, the target gear ratio is set to a lower speed side than the start acceleration mode. Kickdown mode setting means to setAnd a start acceleration mode release determining means for determining release of the start acceleration mode, and a speed ratio until the target speed ratio of the normal speed mode is reached when the start acceleration mode release determining means determines release of the start acceleration mode. And target speed ratio change amount limiting means for limiting the change amount with respect to the change amount in the normal shift mode.
[0016]
In the speed change control device for a continuously variable transmission according to the present invention, until the lockup clutch is completely engaged in the start acceleration mode, the speed change device is at a lower speed than the target speed ratio in the normal speed change mode, and the input side rotating body Since the change amount of the engine speed is set to be large, it is possible to prevent the engine speed from dropping when the lockup clutch is engaged, and to improve the driving feeling. When it is determined that the start acceleration mode is to be released, the target speed ratio change amount is limited until the target speed ratio in the normal speed mode is reached, so the engine speed is controlled so that the target speed ratio is gradually reached. Thus, it is possible to shift to a normal gear ratio with good fuel efficiency without reducing the drop in driving force and deteriorating the driving feeling. Since the start acceleration mode control is performed when the vehicle speed is equal to or lower than the predetermined value, and the kick down control is performed when the vehicle speed is equal to or higher than the predetermined value, simultaneous establishment of the start acceleration mode and the kick down mode can be avoided.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic diagram showing a drive system of a vehicle equipped with a belt-type continuously variable transmission as an example of an automatic transmission. In this continuously variable transmission, the torque of a crankshaft 2 of an engine 1 serves as a fluid transmission mechanism. A drive-side primary shaft 5 transmitted via the converter 3 and the forward / reverse switching device 4 and a driven-side secondary shaft 6 parallel to the drive-side primary shaft 5 are provided.
[0018]
The primary shaft 5 is provided with a primary pulley 7 as an input side rotating body. The primary pulley 7 is a fixed pulley 7a integrated with the primary shaft 5, and a ball spline or the like on the primary shaft 5 opposite thereto. The movable pulley 7b is mounted so as to be slidable in the axial direction, and the cone surface interval of the pulley, that is, the pulley groove width is variable. The secondary shaft 6 is provided with a secondary pulley 8 as an output side rotating body. The secondary pulley 8 is a fixed pulley 8a integrated with the secondary shaft 6, and a movable pulley 7b on the secondary shaft 6 opposite to the fixed pulley 8a. And a movable pulley 8b that is slidably mounted in the axial direction, and the pulley groove width is variable.
[0019]
A belt 9 as a power transmission element is stretched between the primary pulley 7 and the secondary pulley 8, and the ratio of the winding diameter of the belt 9 to each pulley is changed by changing the groove width of both pulleys 7 and 8. Is changed, the rotation of the primary shaft 5 is steplessly changed and transmitted to the secondary shaft 6. If the winding diameter of the drive belt 9 around the primary pulley 7 is Rp and the winding diameter around the secondary pulley 8 is Rs, the gear ratio, i.e., the pulley ratio i is i = Rs / Rp.
[0020]
The rotation of the secondary shaft 6 is transmitted to the drive wheels 11a and 11b via a gear train having a reduction gear and a differential device 10, and in the case of front wheel drive, the drive wheels 11a and 11b are front wheels.
[0021]
In order to change the groove width of the primary pulley 7, a plunger 12 is fixed to the primary shaft 5, and a primary cylinder 13 slidably contacting the outer peripheral surface of the plunger 12 is fixed to the movable pulley 7b. A driving oil chamber 14 is formed by the primary cylinder 13 and the primary cylinder 13. On the other hand, in order to change the groove width of the secondary pulley 8, a plunger 15 is fixed to the secondary shaft 6, and a secondary cylinder 16 slidably contacting the outer peripheral surface of the plunger 15 is fixed to the movable pulley 8b. The plunger 15 and the secondary cylinder 16 form a drive oil chamber 17. Each groove width is set by adjusting the primary pressure Pp introduced into the primary side drive oil chamber 14 and the secondary pressure Ps introduced into the secondary side drive oil chamber 17.
[0022]
The torque converter 3 has a pump-side shell 18 as an input element connected to the crankshaft 2 and a turbine runner 20 as an output element connected to the torque converter output shaft 19. A lockup clutch 22 that engages with a front cover 21 fixed to the side shell 18 is attached, and the torque converter 3 has a lockup clutch. An apply chamber 22a is formed on one side of the lockup clutch 22, and a release chamber 22b is formed on the other side.
[0023]
Adjusted hydraulic fluid is supplied to the apply chamber 22a and the release chamber 22b. When the pressure of the hydraulic fluid in the release chamber 22b is reduced, the lockup clutch 22 is engaged with the front cover 21 by the hydraulic pressure supplied to the apply chamber 22a. As a result, a full lockup state, that is, a clutch engagement state is obtained. On the other hand, the hydraulic pressure supplied to the release chamber 22b is increased and the hydraulic oil is circulated in the torque converter 3 from the release chamber 22b through the apply chamber 22a, whereby the lock-up clutch 22 is released and the torque converter 3 is put into an operating state. Become. Then, by adjusting the hydraulic pressure supplied to the release chamber 22b, the lockup clutch 22 enters a slip lockup state in which the lockup clutch 22 slips with respect to the front cover 21, that is, a half clutch state.
[0024]
FIG. 2 is a schematic diagram showing a speed change control device for a continuously variable transmission. The drive oil chambers 14 and 17 are supplied with hydraulic oil in an oil pan by an oil pump 23 driven by an engine or an electric motor. It has become. The secondary pressure path 24 connected to the discharge port of the oil pump 23 is communicated with the drive oil chamber 17 and is communicated with the secondary pressure port of the secondary pressure regulating valve 25. The secondary pressure Ps supplied to the drive oil chamber 17 by the secondary pressure adjusting valve 25 is adjusted to a pressure commensurate with the transmission capacity required for the belt 9.
[0025]
The secondary pressure passage 24 is connected to the secondary pressure port of the primary pressure adjustment valve 26 via a communication oil passage 27, and the primary pressure port of the primary pressure adjustment valve 26 is connected to the primary side drive oil chamber via the primary pressure passage 28. 14. The primary pressure adjusting valve 26 adjusts the primary pressure Pp to a value corresponding to the target gear ratio, the vehicle speed, etc., and the groove width of the primary pulley 7 is changed to control the gear ratio. The secondary pressure adjustment valve 25 and the primary pressure adjustment valve 26 are proportional solenoid valves, respectively, and the secondary pressure Ps and the primary pressure are controlled by controlling the current value supplied from the transmission control unit 30 to the solenoid coils 25a and 26a. Pp is adjusted. On the other hand, the transmission of the solenoid coil 29a of the proportional solenoid valve 29 for controlling the lockup clutch for adjusting the pressure in the release chamber 22b to set the lockup clutch 22 to the full lockup state, the release state, and the slip state A control signal is sent from the control unit 30.
[0026]
The transmission control unit 30 has a primary pulley rotation speed sensor 31 as an input side rotation speed detection means for detecting the rotation speed of the primary pulley 7 and a detection from a secondary pulley rotation speed sensor 32 for detecting the rotation speed of the secondary pulley 8. A signal is input. Further, an engine speed sensor 33 as an engine speed detection means, a throttle opening sensor 34 for detecting the opening of the throttle valve, a vehicle speed sensor 35 for detecting the traveling speed of the vehicle, and a control lever operated by the driver are selected. Detection signals from a range detection sensor 36 that detects the travel range, an accelerator opening sensor 37 that detects depression of the accelerator pedal, and other various sensors 38 of the rotating system are input to the transmission control unit 30.
[0027]
The transmission control unit 30 includes a microprocessor CPU that calculates control signals for the solenoid coils 25a, 26a, and 29a based on signals from the respective sensors, control data such as tables, maps, and arithmetic expressions, and control data. A ROM for storing the program, a RAM for temporarily storing data, an input / output port, and the like.
[0028]
FIG. 3 is a shift control characteristic diagram showing the relationship between the target rotational speed Np of the primary pulley 7 and the vehicle speed V in the continuously variable transmission shown in FIGS. 1 and 2, for example, when acceleration is performed with the accelerator pedal fully opened. The target rotational speed Np of the primary pulley 7 is low R where the gear ratio is the maximum gear ratio._LThe overdrive R with the speed ratio set to the minimum speed ratio is reached._OThe vehicle speed V is increased while the speed is slightly increased and the vehicle speed V is increased to reach the highest speed point B. If the accelerator pedal is returned or braked from this state, the gear ratio will be overdrive side R_OThen, the vehicle is decelerated through C and D while being fixed, and the gear ratio is shifted from the overdrive to the low side along the lowest transmission line to reach the point E, and the vehicle stops while maintaining low by braking. In actual traveling, the low-side gear ratio R according to the traveling state of the vehicle._LAnd overdrive gear ratio R_OThe transmission ratio is freely set within a range indicated by reference signs A to E.
[0029]
In FIG. 3, low R between points AE_LAnd overdrive R between point CD_OA plurality of thin solid lines between are characteristic lines showing the relationship between the target rotational speed and the vehicle speed when the speed ratio is constant. A plurality of shift lines indicated by broken lines between the highest shift line between the points AB and the lowest shift line between the points DE are shift characteristic diagrams corresponding to the normal shift mode, and each has a predetermined throttle opening. The relationship between the vehicle speed V corresponding to the degree and the target rotational speed Np of the primary pulley 7 is shown. Map data corresponding to the normal transmission mode is stored in a memory such as a ROM in the transmission control unit 30. Therefore, in the normal speed change mode, for example, when the driver depresses the accelerator pedal so that the throttle opening indicated by the point TH in FIG. 3 is reached, the speed change ratio is controlled by the speed change characteristic indicated by the speed change line passing therethrough. Is done. This shift characteristic is stored in the map data for any throttle opening.
[0030]
In FIG. 3, symbol EN indicates a change in the engine speed when the accelerator pedal is depressed so that the throttle opening degree TH is reached. As the engine speed increases and the vehicle speed increases, for example, the engagement of the lockup clutch 22 is started at the vehicle speed V1, and the engine speed is indicated by an arrow G when the engagement is completed at the vehicle speed V2. In addition, if the vehicle is lowered toward the shift line in the normal shift mode, that is, the normal shift rotation speed, the acceleration of the vehicle decreases as described above. There is a problem that the feeling is worsened and the passenger feels uncomfortable.
[0031]
  In the present invention, the vehicle speed is a predetermined value or less.That is, the mode judgment vehicle speed or lessWhen the driver depresses the accelerator pedal at a speed greater than or equal to a predetermined value under the driving condition, that is, the opening speed of the throttle valve is greater than or equal to a predetermined value.That is, the mode judgment opening speed is exceededFurthermore, the throttle valve is more than the predetermined openingIn other words, more than mode judgment openingWhen it becomes, the start acceleration mode is executed. When the start acceleration mode is executed, the speed ratio is set to the maximum speed ratio until the vehicle speed indicated by the symbol F in FIG. Thereafter, until the lock-up clutch 22 is completely engaged, the speed is lower than the target gear ratio in the normal transmission mode indicated by the broken line passing through the throttle opening TH, and the amount of change in the rotation speed of the primary pulley 7 is set to be large. Is done. The start-only characteristics in this start acceleration mode are as indicated by the symbol H in FIG. Moreover, the engine speed EN is increased without decreasing until the lockup clutch 22 is completely engaged.
[0032]
In this manner, while the engine speed is increased after the engagement of the lockup clutch 22 is started, the target speed of the primary pulley 7 is made to approach the engine speed until the lockup clutch 22 is completely engaged. Therefore, when switching to the lock-up clutch engaged state, the feeling of running is improved without causing a feeling of being pulled or slipping. The start acceleration mode is not executed when the throttle opening is equal to or less than the predetermined value.For example, the start acceleration mode is not set in situations where driving and stopping are repeated, such as during traffic jams. Fuel consumption can be improved by performing normal control. Note that the vehicle speed V1 at which engagement of the lockup clutch 22 is started varies depending on the throttle opening and the road surface gradient.
[0033]
After the engagement of the lockup clutch 22 is completed, as indicated by an arrow I in FIG. 3, the engine speed is gradually reduced to approach the shift line in the normal shift mode. The speed ratio control at this time is a transient control so as to limit the speed ratio change amount in the normal speed change control mode by performing a target change amount limiting process. As a result, the drop in driving force during transient control can be reduced, and the normal gear ratio with good fuel efficiency can be restored without deteriorating the driving feeling.
[0034]
As described above, the start acceleration mode is set when the opening speed and the opening of the throttle valve exceed a predetermined value when the vehicle speed is a predetermined value or less. When it is determined that the driver has depressed the accelerator pedal with the intention of rapid acceleration under a predetermined value or more, the kick down mode is set. When the kick down mode is set, the speed change characteristic is set to the low side, that is, the low speed side, rather than the start exclusive characteristic of the start acceleration mode indicated by the symbol H in FIG. The vehicle speed for determining the start acceleration mode and the kick down mode is set to substantially the same vehicle speed, such as 8 km / h. However, the opening speed and opening of the throttle valve set in the kick down mode are set to values larger than those set in the start acceleration mode.
[0035]
  The shift control in the above-described start acceleration mode and kick down mode includes map data for the start acceleration mode and kick down mode stored in a memory such as a ROM in the transmission control unit 30 in addition to the map of the normal shift mode. This is done by reading. Therefore, the transmission control unit 30 has a normal transmission mode setting function, a start acceleration mode determination function, a start acceleration mode setting function, a target gear ratio change amount limiting function, a kick down mode setting function, and the like.And normal shift mode setting means and kick down mode setting means.
[0036]
FIG. 4 is a flowchart showing a main routine of the shift control in the shift control apparatus of the present invention. In step S1, various parameters indicating the running state are read. The parameters are the range position, throttle opening, vehicle speed, etc. selected by the driver's select lever operation. Further, when the accelerator opening sensor 37 is provided as in a vehicle having an electronically controlled throttle, the accelerator opening may be used instead of the throttle opening.
[0037]
A start acceleration mode determination routine is executed in step S2 based on the parameters read in step S1, and the start acceleration mode determination flag F is set when the conditions for executing the start acceleration mode control are satisfied. In step S3, it is determined whether or not the flag F is set. If the flag F is set, the start acceleration mode control described above is executed in step S4. As a result, the gear ratio is set to the maximum gear ratio at the start of starting, and as shown in FIG. 3, when a predetermined vehicle speed F is exceeded, a start-only characteristic speed change control indicated by symbol H is executed. The number will continue to rise. On the other hand, when the flag F is not set, the normal transmission mode control in step S5 is executed, and the transmission ratio is controlled so as to be the transmission characteristic of the normal transmission mode indicated by the broken line in FIG.
[0038]
In step S6, it is determined whether or not the conditions for canceling the start acceleration mode are satisfied. If the release determination is not made, the process of step S4 is continued, and if the release determination is made, the target change amount restriction in step S7 is performed. The processing is executed, and the speed change characteristic is controlled as shown by an arrow I in FIG. This target change amount limiting process is executed until it is determined in step S8 that the target gear ratio of the normal transmission line has been reached. When it is determined that the target speed ratio has been reached, the routine shown in FIG. 4 is exited. Note that the routine shown in FIG. 4 is executed at a calculation cycle of about 20 ms, for example.
[0039]
FIG. 5 is a flowchart showing the start acceleration mode determination subroutine shown in step S2. In step S11, it is determined whether or not the kick down mode is set by depressing the driver's accelerator pedal, and the kick down mode is set. If it is, the start acceleration mode control is not executed. In step S12, it is determined whether or not the select lever is in the D range, that is, the forward travel range position. When another range such as the Ds range is selected, the start acceleration mode is not controlled. In step S13, it is determined whether or not the vehicle speed is a predetermined vehicle speed Vd, for example, 8 km / h or less. When the vehicle speed is equal to or higher than a predetermined value, the engine speed does not blow up and the driving feeling does not deteriorate when starting. The start acceleration mode control is not performed.
[0040]
Further, in step S14, it is determined whether or not the speed at which the throttle valve is opened, that is, the opening speed is a predetermined value THd, for example, 6 degrees / 2 seconds or more. In step S15, the throttle valve opening is determined to be a predetermined value THA, for example, 12 degrees. It is determined whether or not this is the case. Thereby, when the opening speed of the throttle valve is less than a predetermined value or when the opening degree is less than a predetermined value, the start acceleration mode control is not performed in order to emphasize the fuel consumption. In step S16, it is determined whether or not the throttle opening sensor 34 or the accelerator opening sensor 37 has failed.
[0041]
Based on the determination results in these steps S11 to S16, when the above-described conditions are satisfied, the start acceleration mode determination flag F is set at step S17, and when the conditions are not satisfied, the start acceleration mode is set at step S18. The determination flag F is reset. Further, in addition to the determinations in steps S11 to S16, whether or not the oil temperature of the transmission is equal to or higher than a predetermined value, whether or not the temperature of the engine cooling water is equal to or higher than a predetermined value, and the rotation of the secondary pulley 8 The start acceleration mode determination flag may be set by determining whether or not the secondary pulley rotation speed sensor 32 that detects the number is out of order.
[0042]
FIG. 6 is a flowchart showing a determination routine for canceling the start acceleration mode. In step S21, it is determined whether or not the kick down K / D mode is set. If the K / D mode is determined, the start acceleration is performed. The mode is released. In step S22, it is determined whether or not the select lever is in the D range, that is, the forward travel range position. When a range other than the D range is selected, the start acceleration mode is canceled. Further, in step S23, it is determined whether or not the opening speed of the throttle valve is a predetermined value THe, for example, 0 degrees / 2 seconds or less. When the throttle valve opening speed is smaller than the predetermined value, the start acceleration mode is canceled to emphasize fuel consumption. In step S24, it is determined whether or not the throttle opening sensor 34 or the accelerator opening sensor 37 has failed, and when it has failed, the start acceleration mode is canceled.
[0043]
In step S25, the release determination throttle opening THB is calculated from the vehicle speed and the road surface gradient, and in step S26, the timer starts counting. If the throttle opening TH is larger than the release determination throttle opening THB calculated in step S25, the routine is exited. If the throttle opening TH is smaller, it is determined in step S28 whether or not the small state has exceeded a predetermined time TA. If the predetermined time has not elapsed, the timer is counted up in step S29 and returned to step S27. If the predetermined time has elapsed, the start acceleration mode determination flag F is reset in step S30 and the routine is exited.
[0044]
In this way, when the throttle opening TH is smaller than the predetermined release determination throttle opening THB for a predetermined time, the lockup engagement is terminated, and the start acceleration is performed to return to the normal shift line focusing on fuel consumption. Release mode control. The road slope is included in the parameter for setting the throttle opening for release determination. In order to improve the release performance on an uphill road, the lock-up engagement condition is determined by the throttle opening and the slope. The throttle opening means that the lockup engagement has been completed. Further, by setting the time condition, hunting is prevented and the lockup clutch is reliably controlled.
[0045]
The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention. For example, the continuously variable transmission shown in FIG. 1 is a belt type, but the present invention may be applied to control of a continuously variable transmission of a type that uses a chain as a power transmission medium. The present invention may be applied to control of a toroidal continuously variable transmission in which a power roller is disposed as a power transmission element between an input side disk and an output side disk as an output side rotating body.
[0046]
【The invention's effect】
According to the present invention, until the lockup clutch is completely engaged, the speed change rate is set to be lower than the target speed ratio in the normal speed change mode and the rotational speed of the input side rotating body is set large. It is possible to prevent the engine speed from dropping when the up-clutch is engaged, and to improve driving feeling. After the lockup clutch is engaged, the target speed ratio change amount is limited until the target speed ratio in the normal speed mode is reached, so the engine speed is controlled so that the target speed ratio is gradually reached. Thus, it is possible to shift to a normal gear ratio with good fuel efficiency without reducing the drop in driving force and deteriorating the driving feeling. Since the start acceleration mode control is performed when the vehicle speed is equal to or lower than the predetermined value, and the kick down control is performed when the vehicle speed is equal to or higher than the predetermined value, simultaneous establishment of the start acceleration mode and the kick down mode can be avoided.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing a drive system of a vehicle including a belt type continuously variable transmission as an example of an automatic transmission.
FIG. 2 is a schematic diagram showing a transmission control device for a continuously variable transmission.
FIG. 3 is a shift characteristic diagram showing a relationship between a target speed of a primary pulley and a vehicle speed in a continuously variable transmission.
FIG. 4 is a flowchart showing a main routine of shift control.
FIG. 5 is a flowchart showing a subroutine for starting acceleration mode determination.
FIG. 6 is a flowchart showing a start acceleration mode release determination routine.
[Explanation of symbols]
1 engine
3 Torque converter
7 Primary pulley
8 Secondary pulley
9 Belt
22 Lock-up clutch
30 Transmission control unit
31 Primary pulley speed sensor
32 Secondary pulley speed sensor
33 Engine speed sensor
34 Throttle opening sensor
35 Vehicle speed sensor
36 Range position detection sensor
37 Accelerator position sensor

Claims (6)

A continuously variable transmission that continuously changes the rotation of the input side rotating body via the power transmission element and transmits it to the output side rotating body, and a lock-up clutch provided between the engine and the continuously variable transmission A transmission control device for a continuously variable transmission including a torque converter,
Normal transmission mode setting means for setting the target rotational speed of the input-side rotator to a normal transmission rotational speed based on a parameter indicating an operating state;
Start acceleration mode determination means for determining when the vehicle starts acceleration;
When the vehicle speed is not more than a predetermined value, the opening degree of the throttle valve is not less than a predetermined value, and the opening speed of the throttle valve is not less than a predetermined value and the start acceleration mode determining means determines the start acceleration mode, Starting from the time when the rear shift is started until the lock-up clutch is engaged, the speed is lower than the target gear ratio in the normal shift mode, and the amount of change in the rotational speed of the input-side rotator is set larger than that in the normal shift mode. Acceleration mode setting means ;
When the vehicle speed is equal to or higher than the predetermined value, the opening degree of the throttle valve is larger than the predetermined value, and the opening speed of the throttle valve is larger than the predetermined value, the target gear ratio is set to the lower speed side than the start acceleration mode. And a kick-down mode setting means for controlling the continuously variable transmission. In the shift control device for a continuously variable transmission according to claim 1, wherein the starting acceleration mode determining means, when A Kuseru opening is above a predetermined value, and the accelerator opening speed is equal to or greater than a predetermined value, the starting acceleration mode A shift control device for a continuously variable transmission, characterized in that The shift control device for a continuously variable transmission according to claim 1 or 2 , wherein a start acceleration mode release determination means for determining release of the start acceleration mode and a start acceleration mode release determination by the start acceleration mode release determination means are determined. Shift control for a continuously variable transmission, characterized by comprising target speed ratio change amount limiting means for limiting the speed ratio change amount from the speed ratio change amount in the normal speed mode until the target speed ratio for normal control is reached. apparatus. 4. The speed change control device for a continuously variable transmission according to claim 3 , wherein the start acceleration mode release determination means starts acceleration when the opening of the throttle valve is not more than a predetermined value and the opening continues for a predetermined time. A speed change control device for a continuously variable transmission, characterized in that mode release is determined. 4. The speed change control device for a continuously variable transmission according to claim 3 , wherein the start acceleration mode release determination means is configured to start start acceleration mode when the accelerator opening is equal to or less than a predetermined value and the opening continues for a predetermined time. A shift control device for a continuously variable transmission, wherein release is determined. A continuously variable transmission that continuously changes the rotation of the input side rotating body via the power transmission element and transmits it to the output side rotating body, and a lock-up clutch provided between the engine and the continuously variable transmission A transmission control device for a continuously variable transmission including a torque converter,
A normal transmission mode setting means for setting the target rotational speed of the input-side rotator to a normal transmission rotation based on a parameter indicating an operation state;
Start acceleration mode determination means for determining when the vehicle starts acceleration;
When the vehicle speed is not more than a predetermined value, the opening degree of the throttle valve is not less than a predetermined value, and the opening speed of the throttle valve is not less than a predetermined value and the start acceleration mode determining means determines the start acceleration mode, Starting from the time when the rear shift is started until the lock-up clutch is engaged, the speed is lower than the target gear ratio in the normal shift mode, and the amount of change in the rotational speed of the input-side rotator is set larger than that in the normal shift mode. Acceleration mode setting means ;
When the vehicle speed is equal to or higher than the predetermined value, the opening degree of the throttle valve is larger than the predetermined value, and the opening speed of the throttle valve is larger than the predetermined value, the target gear ratio is set to the lower speed side than the start acceleration mode. Kick down mode setting means to perform,
Start acceleration mode release determination means for determining release of the start acceleration mode;
When the start acceleration mode release determining means determines release of the start acceleration mode, the target speed ratio change amount that limits the speed change amount until the target speed ratio of the normal speed change mode is reached with respect to the change amount of the normal speed change mode. And a speed change control device for a continuously variable transmission.

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