JP2004116641A - Speed change controller of continuously-variable transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve travelling quality when switching a lock-up clutch from a releasing state to an engaging state. <P>SOLUTION: A torque converter with the lock-up clutch is arranged between the continuously-variable transmission having a primary pulley and a secondary pulley and transmitting revolutions of an input shaft to an output shaft in a continuously-variable state by changing each width of pulley grooves and an engine. A speed change controller sets up a target revolution of the primary pulley in a regular revolution of speed change based on a parameter showing an operating state such as speed of a vehicle and a throttle position, and also sets up the target revolution in a starting revolution lower than the regular revolution of speed change until completing engagement of the lock-up clutch. Deviation between the starting revolution and the regular revolution of speed change gets smaller while the throttle position or an accelerator position gets larger. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a shift control device for a continuously variable transmission having a torque converter with a lock-up clutch.
[0002]
[Prior art]
Continuously variable transmissions used in vehicles such as automobiles include a belt type and a toroidal type. The belt-type continuously variable transmission includes 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 bridged between these pulleys. are doing. By changing the groove width of each pulley and changing the winding diameter of the power transmission element, the gear ratio changes steplessly, and the rotation of the input shaft can be controlled and transmitted to the output shaft at a predetermined speed. it can.
[0003]
The shift control device of such a continuously variable transmission has a memory in which a normal shift characteristic map is stored, and refers to the normal shift characteristic map based on parameters indicating an operating state such as a throttle opening and a vehicle speed. Then, the target rotation speed of the primary pulley is set, and the following control is performed so that the actual primary pulley rotation speed converges to the target rotation speed. For example, when the accelerator pedal is depressed to accelerate the vehicle speed, the target rotation speed of the primary pulley is controlled so that a target speed ratio corresponding to the throttle opening, that is, a speed change line is obtained. As a result, the gear ratio is continuously controlled from low to overdrive, but the target rotation speed of the primary pulley, which is calculated based on the throttle opening and the vehicle speed, is adjusted in consideration of the normal driving feeling. The target gear ratio shifts to the overdrive side as the opening degree decreases.
[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 reduce the power of the engine to the primary. The lock-up clutch is preferably engaged with the vehicle at the lowest possible speed from the viewpoint of fuel efficiency, but when the lock-up clutch is engaged, the engine speed decreases toward the shift line. Will do.
[0005]
[Problems to be solved by the invention]
In particular, when the throttle opening is low, that is, in the state of a low shift line, and the vehicle speed is low when starting, etc., the deviation between the engine speed and the primary pulley speed is large. If the lock-up clutch is engaged from the viewpoint of emphasizing fuel consumption at the time, the engine speed will decrease significantly toward the shift line. When the engine speed decreases in this way, the acceleration of the vehicle decreases, so that a feeling of being pulled in or a slipping feeling is generated, a driving feeling and a running feeling are deteriorated, and a problem arises that an occupant feels uncomfortable.
[0006]
In order to eliminate a sense of incongruity due to a shock at the time of engagement of the lock-up clutch or fluctuations in the engine speed, for example, in a shift control device disclosed in JP-A-8-326891, the lock-up release state and the lock-up release state are changed to the engagement state. During this process, the gear ratio is controlled so that the rotational difference between the input and output shafts of the torque converter, that is, the slip rotation, is eliminated, and the lock-up clutch is engaged without changing the engine speed.
[0007]
However, the driving force transmitted from the engine to the drive wheels via the transmission is large when the lock-up clutch is released and the torque converter is operating, becomes small when the lock-up clutch is engaged, and becomes small when the lock-up clutch is engaged. It changes depending on the engagement of the clutch. This change in the driving force is larger when the vehicle is starting at a low vehicle speed, for example, when the throttle opening is small than when the throttle opening is large, and gives an uncomfortable feeling to the occupant.
[0008]
An object of the present invention is to improve the running feeling when the lock-up clutch is switched from the disengaged state to the engaged state.
[0009]
[Means for Solving the Problems]
A shift control device for a continuously variable transmission according to the present invention includes a continuously variable transmission that changes the rotation of an input-side rotating body in a stepless manner via a power transmission element and transmits the rotation to an output-side rotating body, an 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 transmission. A normal speed mode setting means for setting the speed change speed, a start mode determining means for determining when the vehicle starts, and when the start mode determining means determines that the vehicle is in the start mode, the lockup clutch is not engaged. The target rotation speed of the input-side rotator is set to a start rotation speed that is lower than the normal speed rotation speed, and the start rotation speed increases as the throttle valve opening increases. And having a launch mode setting means for setting a small deviation between the number and the normal shift speed.
[0010]
In the shift control device for a continuously variable transmission according to the present invention, the normal shift mode setting means includes normal shift map data for setting a target rotation speed of the input-side rotator based on a parameter indicating an operation state, The mode setting means has start shift map data for setting the start rotation speed from the release state of the lock-up clutch to the completion of engagement.
[0011]
In the shift control device for a continuously variable transmission according to the present invention, the normal shift mode setting means includes normal shift map data for setting a target rotation speed of the input-side rotator based on a parameter indicating an operation state, The mode setting means is characterized in that the start rotation speed from the disengagement state of the lock-up clutch to the completion of engagement is calculated by subtracting from the normal shift map data.
[0012]
In the shift control device for a continuously variable transmission according to the present invention, the target rotation speed of the input-side rotator before the lock-up clutch is engaged is set to the starting rotation speed that is lower than the normal speed rotation speed. At the same time, as the opening of the throttle valve increases, the deviation between the starting rotation speed and the normal speed rotation speed is set to be small, so that the driving force transmitted to the driving wheels from when the vehicle starts until the vehicle reaches a predetermined vehicle speed is obtained. Can be made gentle, and the running feeling at the time of starting until the engagement of the lock-up clutch is completed can be improved.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic diagram showing a drive system of a vehicle provided with a belt-type continuously variable transmission as an example of an automatic transmission. In this continuously variable transmission, the rotation of a crankshaft 2 of an engine 1 is controlled by a torque as a fluid transmission mechanism. It has a primary shaft 5 on the driving side transmitted via the converter 3 and the forward / reverse switching device 4 and a secondary shaft 6 on the driven side which is parallel to the primary shaft 5.
[0014]
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 is attached to the primary shaft 5 in opposition thereto. And a movable pulley 7b which is slidably mounted in the axial direction, and the gap between the cone surfaces 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 And a movable pulley 8b that is slidably mounted in the axial direction in the same manner as described above, and the pulley groove width is variable.
[0015]
A belt 9 as a power transmission element is stretched between the primary pulley 7 and the secondary pulley 8, and the groove width of both pulleys 7 and 8 is changed to change the ratio of the winding diameter of the belt 9 to each pulley. Is changed, the rotation of the primary shaft 5 is transmitted to the secondary shaft 6 at a continuously variable speed. Assuming that 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, that is, the pulley ratio i is i = Rs / Rp.
[0016]
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 become front wheels.
[0017]
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 drive oil chamber 14 is formed by the 12 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. A driving oil chamber 17 is formed by the plunger 15 and the secondary cylinder 16. Each groove width is set by adjusting the primary pressure Pp introduced into the primary driving oil chamber 14 and the secondary pressure Ps introduced into the secondary driving oil chamber 17.
[0018]
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 lock-up clutch 22 that engages with a front cover 21 fixed to the side shell 18 is attached, and the torque converter 3 has a lock-up clutch. An apply chamber 22a is formed on one side of the lock-up clutch 22, and a release chamber 22b is formed on the other side.
[0019]
Adjusted hydraulic oil is supplied to the apply chamber 22a and the release chamber 22b. When the pressure of the hydraulic oil in the release chamber 22b is reduced, the lock-up clutch 22 is engaged with the front cover 21 by the hydraulic pressure supplied to the apply chamber 22a. In total, a full lock-up state, that is, a clutch engagement state is established. On the other hand, by increasing the hydraulic pressure supplied to the release chamber 22b and circulating the hydraulic oil from the release chamber 22b through the apply chamber 22a in the torque converter 3, the lock-up clutch 22 is released, and the torque converter 3 is brought into the operating state. Become. Then, by adjusting the hydraulic pressure supplied to the release chamber 22b, the lock-up clutch 22 is brought into a slip lock-up state in which the front cover 21 slips, that is, a half-clutch state.
[0020]
FIG. 2 is a schematic diagram showing a shift control device of the continuously variable transmission, in which 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. Has become. The secondary pressure passage 24 connected to the discharge port of the oil pump 23 is connected to the driving oil chamber 17 and to 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 corresponding to the transmission capacity required for the belt 9.
[0021]
The secondary pressure passage 24 is connected to a 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 via a primary pressure passage 28 to a primary-side drive oil chamber. 14. The primary pressure adjusting valve 26 adjusts the primary pressure Pp to a value corresponding to the target speed ratio, the vehicle speed, and the like, and changes the groove width of the primary pulley 7 to control the speed ratio. The secondary pressure regulating valve 25 and the primary pressure regulating valve 26 are proportional solenoid valves, respectively. The secondary pressure Ps and the primary pressure Ps are controlled by controlling current values supplied from the transmission control unit 30 to the respective solenoid coils 25a and 26a. Pp is adjusted. On the other hand, a transmission is connected to a solenoid coil 29a of a proportional solenoid valve 29 for controlling a lock-up clutch for controlling the pressure of the release chamber 22b to set the lock-up clutch 22 to a full lock-up state, a release state, and a slip state. A control signal is sent from the control unit 30.
[0022]
The transmission control unit 30 includes a primary pulley rotation speed sensor 31 as 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 detecting means, a throttle opening sensor 34 for detecting an opening of a throttle valve, a vehicle speed sensor 35 for detecting a running speed of the vehicle, and a control lever operated by a driver are selected. Detection signals from a range detection sensor 36 for detecting the set traveling range, an accelerator opening sensor 37 for detecting depression of an accelerator pedal, and various other sensors 38 of the rotation system are input to the transmission control unit 30.
[0023]
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 respective sensors and the like, control data such as tables, maps, and arithmetic expressions, and control data. And a ROM for temporarily storing data, an input / output port, and the like.
[0024]
In this transmission control device, the lock-up clutch 22 of the torque converter 3 provided between the engine 1 and the continuously variable transmission selects the D range, that is, the forward travel range by the driver's operation of the select lever. When the traveling speed becomes, for example, about 8 km / h, the engagement state is controlled by a signal from the vehicle speed sensor 35, the range detection sensor 36, or the like.
[0025]
FIG. 3 is a shift control characteristic diagram showing a relationship between target speed Np of primary pulley 7 and vehicle speed V in the continuously variable transmission shown in FIGS. 1 and 2, for example, when accelerating with the accelerator pedal fully opened. , the target rotational speed Np of the primary pulley 7 is reached while the point a of the low R _L gear ratio is the largest gear ratio, then slightly along with the shift to overdrive R _O side speed ratio is minimum speed ratio The vehicle speed V is increased while increasing the rotation to reach the highest speed point B. Or releases the accelerator pedal from the state, C remains the gear ratio is fixed to the overdrive side R _O in the case of performing the braking, slowing through D, the gear ratio is an overdrive further along the lowest transmission line Is shifted to the low side to reach the point E, and the vehicle stops at the low level due to braking. In actual running, according to the running state of the vehicle, it is between the gear ratio R _O of the gear ratio of the low side R _L and the overdrive side, freely gear ratio within the range indicated by E from the code A Is set.
[0026]
Characteristic diagram respectively speed ratio plurality of thin solid line shows the relationship between the target speed and the vehicle speed in the case of a constant between the overdrive R _O between the low R _L and the point CD between points AE in FIG. 3 is there. 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, each of which has a predetermined throttle opening. The relationship between the vehicle speed V corresponding to the degree and the target rotation speed Np of the primary pulley 7 is shown. The map data corresponding to the normal shift mode is stored in a memory such as a ROM in the transmission control unit 30. Therefore, in the normal shift mode, for example, when the accelerator pedal is depressed by the driver so as to have the throttle opening indicated by point TH1 in FIG. 3, the shift ratio is controlled by the shift characteristics indicated by the shift line passing through the accelerator pedal. Is done. Similarly, when the accelerator pedal is depressed so as to have a throttle opening larger than the point TH1 and an opening indicated by the point TH2, the gear ratio is controlled by the shift characteristic indicated by the shift line passing through the accelerator pedal. . This shift characteristic is stored in the map data for each throttle opening.
[0027]
In FIG. 3, symbols EN1 and EN2 indicate changes in the engine speed when the accelerator pedal is depressed so as to attain the corresponding throttle opening degrees TH1 and TH2, respectively. As the engine speed increases and the vehicle speed increases, for example, the engagement of the lock-up clutch 22 starts at the vehicle speed V1, and when the engagement is completed at the vehicle speed V1, the primary rotation speed is changed to the normal shift mode. When the speed of the line, that is, the primary speed is set to the normal speed, which is small, the engine speed falls as indicated by arrows G1 and G2, and the acceleration of the vehicle decreases as described above. There is a problem that a feeling of slippage and a feeling of slippage occur, the driving feeling and the running feeling are deteriorated, and the occupant is given a sense of discomfort.
[0028]
In the present invention, the start mode is executed until the engagement of the lock-up clutch 22 is completed. When the start-up mode is set, when the lock-up clutch 22 is released and the torque converter 3 is in the operating state, the gear ratio is set so that the throttle opening is smaller than the shift line in the normal shift mode. That is, the target rotation speed Np of the primary pulley 7 is set to the starting rotation speed that is lower than the normal speed rotation speed in the normal speed change mode. The reduction amount of the target rotation speed with respect to the normal rotation speed of the starting rotation speed may be set to be the same as the deviation between the engine rotation speed and the target rotation speed in the normal transmission mode, or set to a reduction amount close thereto. Is also good.
[0029]
Then, when the engagement of the lock-up clutch 22 is started, the gear ratio and the engine speed are transiently controlled so as to converge on the shift line in the normal shift mode. That is, the start rotation speed in the transient control is set to the low side so that the lockup clutch 22 becomes the normal speed rotation speed in the normal speed change mode when the lockup clutch 22 is engaged, in other words, the engagement is started after the lockup clutch 22 starts engagement. Since the rotation speed of the primary pulley is increased from the normal speed change mode until the completion, the engine rotation speed can be prevented from being greatly reduced. Therefore, when switching the lock-up clutch 22 from the disengaged state to the engaged state, the running feeling is improved without the occurrence of a retracted feeling or a slipping feeling. The vehicle speed V1 at which engagement of the lock-up clutch 22 is started changes according to the engine speed and the road surface gradient.
[0030]
As described above, the speed ratio in the start mode, that is, the speed change line, is set to a start speed in which the target speed Np of the primary pulley 7 is lower than that in the speed change line in the normal speed mode. It is set so that the smaller the θ is, the larger the decrease amount becomes. For example, when the accelerator pedal is depressed so that the throttle opening becomes TH1, the target rotation speed Np of primary pulley 22 with respect to the normal speed change line is lower than when the accelerator pedal is depressed so that the opening becomes TH2. The starting rotation speeds H1 and H2 are set so that the amounts become large. Therefore, the deviation between the engine speed and the target speed Np of the primary pulley 7 increases as the throttle opening θ decreases.
[0031]
The control of the starting rotation speed until the lock-up clutch 22 is completely engaged may be performed based on the starting shift map data stored in the memory, and the deviation is subtracted from the normal shift map data stored in the memory. You may ask for it. When the deviation is subtracted, the amount of data stored in the memory can be reduced as compared with the case where the starting shift map data is set. Therefore, the transmission control unit 30 has a normal shift mode setting function, a start mode determination function, a start mode setting function, and the like.
[0032]
FIG. 4 is a characteristic diagram showing a change in the driving force transmitted to the driving wheels until the vehicle starts moving up to a predetermined speed by depressing the accelerator pedal. Until completion, in the case of the shift control in the normal shift mode, when the engine speed is greatly reduced as indicated by arrows G1 and G2 in FIG. 3, the drive until the engagement of the lock-up clutch 22 is completed is completed. The force changes as shown by the dashed line in FIG. On the other hand, when the start mode is provided, the driving force from the start of the start of the vehicle to the predetermined vehicle speed changes gently as a whole, and the driving feeling is improved. Further, since the deviation between the starting rotation speed and the normal speed rotation speed is changed in accordance with the throttle opening, the change in the driving force is set to an optimum state in accordance with the throttle opening.
[0033]
FIG. 5 shows the target rotation speed of the primary pulley 7, that is, the deviation ΔN between the start rotation speed and the engine rotation speed under the state where the lock-up clutch 22 is released and the start mode is set, and the vehicle speed. FIG. 7 is a characteristic diagram showing that the value is changed according to V and a throttle opening θ. As shown in FIG. 5, under the state where the lockup clutch 22 is released, the smaller the throttle opening θ, the larger the deviation ΔN between the engine speed and the starting speed is set so as to increase the vehicle speed V Is set so that the deviation ΔN increases as the value of.
[0034]
FIG. 6 is a characteristic diagram showing that the deviation ΔN when the lock-up clutch 22 starts to be engaged is changed according to the vehicle speed V and the throttle opening θ. As the throttle opening becomes smaller, the engine speed increases. Is set so as to increase the deviation ΔN between the rotation speed and the starting rotation speed. As shown in FIG. 6, when engagement of the lock-up clutch 22 is started, the deviation ΔN between the starting rotational speed and the engine rotational speed is set to be larger as the throttle opening is smaller.
[0035]
FIG. 7 is a flowchart showing the main routine of the shift control in the shift control device of the present invention. The parameters are a range position, a throttle opening, a vehicle speed, and the like selected by the driver operating the select lever. Further, when the vehicle has an accelerator opening sensor 37 as in a vehicle having an electronic control throttle, the accelerator opening may be used instead of the throttle opening.
[0036]
A start mode determination routine is executed in step S2 based on the parameters read in step S1, and a start mode determination flag F is set when the conditions for executing the start mode are satisfied. In step S3, it is determined whether or not the flag F is set. If the flag F is set, the start mode control is executed in step S4. If the flag F is not set, the process proceeds to step S4. In S5, the normal shift mode control is executed. The routine shown in FIG. 7 is executed at a calculation cycle of, for example, about 20 ms.
[0037]
FIG. 8 is a flowchart showing a subroutine for starting mode determination shown in step S2 in FIG. 7. In step S11, it is determined whether or not the driver intends to rapidly depress the accelerator pedal to rapidly accelerate the vehicle. It is determined whether the / D mode is set or not. When the kick down mode is determined, another setting for shifting the speed change line to the lower speed side is performed, and the start mode control is not performed because emphasis is placed on acceleration. . In step S12, it is determined whether or not the select lever is at the D range, that is, the forward travel range position. When another range such as the Ds range is selected, the start mode control is not performed. In step S13, it is determined whether or not the vehicle speed is equal to or lower than a predetermined vehicle speed Vd, for example, 8 km / h. If the vehicle speed is equal to or higher than the predetermined value, it is not at the time of starting, but the engine speed does not increase and the driving feeling deteriorates. No start mode control is performed. Further, in step S14, it is determined whether or not the lock-up clutch 22 is in the released state. When the engagement of the lock-up clutch 22 has been completed, the start mode control is not performed. In step S15, it is determined whether the throttle opening sensor 34 or the accelerator opening sensor 37 has failed.
[0038]
Based on the determination results in steps S11 to S15, if the vehicle speed satisfies a condition such as a certain value or less, the start mode determination flag is set in step S16. If the condition is not satisfied, the process proceeds to step S17. The start mode determination flag is reset. Further, in addition to the determinations in steps S11 to S15, whether the oil temperature of the transmission is equal to or higher than a predetermined value, whether the temperature of engine cooling water is equal to or higher than a predetermined value, and the rotation of the secondary pulley 8 The start 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.
[0039]
FIG. 9 is a flowchart showing a subroutine of the start mode control in FIG. 7. In step S21, it is determined whether or not the lock-up clutch 22 is in an engagement start state. That is, it is determined whether or not the engagement start state V1 has been reached in the characteristic diagram shown in FIG. If NO in step S21, that is, if it is determined that the vehicle is not in the engagement start state, the vehicle speed is not at V1, and the starting rotational speed that is the target rotational speed NPTG of the primary pulley is stored in the map stored in the memory. Control is performed based on the data f1 (θ, v). On the other hand, if “YES” is determined in the step S21, it is a state of the transient control between V1 and V2 in FIG. 3, and the target rotation speed NPTG of the primary pulley is stored in the map data f2 (θ, v) stored in the memory. The starting rotation speed is controlled based on the starting rotation speed.
[0040]
FIG. 10 is a flowchart showing a subroutine of another control method of the start mode control. In step S24, the target rotation speed in the normal shift mode based on the map data f (θ, v) stored in the memory as the normal shift mode. NPTG1 is read, and it is determined in step S25 whether or not the lock-up clutch 22 is in the engagement start state as in step S21. If it is determined in step S25 that the engagement state is not established, step S26 is executed, and the deviation ΔN between the target rotation speed in the normal shift mode and the target rotation speed in the start mode is determined by the throttle opening θ and the vehicle speed V. Is obtained by an arithmetic expression ΔN = f3 (θ, V) using On the other hand, if it is determined that the vehicle is in the engaged state, step S27 is executed, and a similar deviation ΔN is obtained by the arithmetic expression ΔN = f4 (θ, V). In step S28, the deviation ΔN is subtracted from the target rotation speed NPTG1 of the primary pulley in the normal speed change mode obtained in step S24 to calculate the target rotation speed NPTG. As a result, in the start mode, the starting rotation speed is controlled to the same as when the map data is read and controlled.
[0041]
The present invention is not limited to the above embodiment, and can be variously modified without departing from the gist thereof. For example, the continuously variable transmission shown in FIG. 1 is a belt type, but the present invention may be applied to the control of a continuously variable transmission of a type using a chain as a power transmission medium. The present invention may be applied to the control of a toroidal type 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.
[0042]
【The invention's effect】
According to the present invention, the target rotation speed of the input-side rotator before the lock-up clutch is engaged is set to the starting rotation speed lower than the normal speed rotation speed, and the opening degree of the throttle valve increases. , The deviation between the starting rotation speed and the normal speed rotation speed is set to be small, so that the primary speed can be increased from the normal speed rotation speed from the start of engagement of the lock-up clutch to the completion of the engagement, and the turbine speed can be increased. The lock-up clutch can be engaged without lowering the engine speed, and the deviation between the starting rotational speed and the normal shift rotational speed can be reduced when the deviation between the engine rotational speed and the primary rotational speed is small and the throttle opening is large. Therefore, acceleration can be maintained. Therefore, it is possible to make the change in the driving force transmitted to the drive wheels from the start of the vehicle to the predetermined vehicle speed gentle, and to improve the driving feeling at the time of starting until the engagement of the lock-up clutch is completed. Can be improved.
[Brief description of the drawings]
FIG. 1 is a schematic diagram illustrating 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 shift control device of the continuously variable transmission.
FIG. 3 is a shift characteristic diagram showing a relationship between a target rotation speed of a primary pulley and a vehicle speed in a continuously variable transmission.
FIG. 4 is a characteristic diagram showing a change in driving force transmitted to driving wheels until the vehicle speed starts and reaches a predetermined vehicle speed.
FIG. 5 is a characteristic diagram showing a relationship between a deviation between a target rotation speed of a primary pulley and an engine rotation speed in a state where a lock-up clutch is released, and a throttle opening in accordance with a vehicle speed.
FIG. 6 is a characteristic diagram illustrating a relationship between a deviation and a throttle opening according to a vehicle speed when the lock-up clutch is in an engagement start state.
FIG. 7 is a flowchart showing a main routine of a shift control.
FIG. 8 is a flowchart illustrating a subroutine for starting mode determination.
FIG. 9 is a flowchart showing a subroutine of start mode control.
FIG. 10 is a flowchart showing a subroutine of another control method of the start mode control.
[Explanation of symbols]
DESCRIPTION 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 degree sensor 35 Vehicle speed sensor 36 Range position Detection sensor 37 Accelerator opening sensor

Claims (3)

With a continuously variable transmission that continuously changes the rotation of the input side rotating body via a power transmission element and transmits the rotation to the output side rotating body, and a lock-up clutch provided between the engine and the continuously variable transmission. A shift control device for a continuously variable transmission including a torque converter,
Normal speed mode setting means for setting a target speed of the input-side rotator to a normal speed speed based on a parameter indicating an operation state;
Start mode determining means for determining when the vehicle starts,
When the start mode is determined by the start mode determining means, the target rotation speed of the input-side rotator before engaging the lock-up clutch is set to a start rotation speed that is lower than the normal speed rotation speed. A shift control device for a continuously variable transmission, comprising: start mode setting means for setting and setting a smaller difference between a start rotation speed and a normal shift rotation speed as the opening of the throttle valve increases. 2. The shift control device for a continuously variable transmission according to claim 1, wherein the normal shift mode setting means has normal shift map data for setting a target rotation speed of the input-side rotator based on a parameter indicating an operation state, A shift control device for a continuously variable transmission, wherein the start mode setting means includes start shift map data for setting the start rotation speed from the release state of the lock-up clutch to the completion of engagement. 2. The shift control device for a continuously variable transmission according to claim 1, wherein the normal shift mode setting means has normal shift map data for setting a target rotation speed of the input-side rotator based on a parameter indicating an operation state, A shift control device for a continuously variable transmission, wherein the start mode setting means calculates the start rotational speed from the disengagement state of the lock-up clutch to the completion of engagement by subtracting the start rotational speed from the normal shift map data.

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