JP3293531B2 - Control device for continuously variable transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a continuously variable transmission mounted on a vehicle, and more particularly to a control device for improving a vehicle starting characteristic on a low friction coefficient road surface such as a frozen road surface or a wet tiled road surface. It was made.

[0002]

2. Description of the Related Art In general, in a vehicle transmission, in order to ensure stable running on a low friction coefficient road surface such as an icy road or a swayed tile road surface, for example, "NISSAN full-range electronically controlled automatic transmission FULL" is used.
As described in "RANGE 5E-AT Maintenance Manual" (issued in June 1989), select "AUTO" for normal running and "SNOW" for running on a low friction coefficient road with the A / T mode switch. When the "AUTO" mode is selected, the D range pattern having the shift lines from the first speed to the fifth speed during normal running is selected, and "SN" is selected.
When the "OW" mode is selected, as shown in FIG. 16, by adopting the shift pattern for the snow mode in which the first and second speed states are removed from the D range pattern, the slip when starting the vehicle on the road surface with a low friction coefficient is adopted. And good starting characteristics are obtained.

[0003]

However, in the above conventional vehicle transmission, the transmission is an automatic transmission, and the transmission ratio can be set freely when the vehicle starts moving. In a belt type continuously variable transmission or a toroidal type continuously variable transmission, a forward / reverse switching mechanism is provided on an input side connected to the engine, and when the vehicle is stopped, rotation from the engine to the continuously variable transmission is performed. When the input of the driving force is interrupted, the rotational driving force from the engine is transmitted to the input side via the forward / reverse switching mechanism when the vehicle starts moving, so that the gear can be shifted for the first time, When the vehicle stops, the speed ratio of the continuously variable transmission is returned to the maximum speed ratio in the normal running state.
Even when a limited speed change pattern in which the maximum speed ratio in the speed change pattern during normal running is limited to the minimum speed ratio corresponding to the OW "mode is selected, the vehicle starts at the maximum speed ratio in the normal running state when the vehicle starts. When starting on a low friction coefficient road surface such as a frozen road surface or a wet tile road surface,
There is an unsolved problem that the driving torque is too large, which causes wheel slip and deteriorates the vehicle starting characteristics.

Accordingly, the present invention has been made in view of the above-mentioned unsolved problems of the prior art, and has a limitation in which the maximum speed ratio in the speed change pattern during normal running when starting the vehicle is limited to the minimum speed ratio side. A control device for a continuously variable transmission that improves the starting characteristics of a vehicle by reducing the output of a rotational drive source that transmits rotational driving force to the continuously variable transmission when a shift pattern is selected. It is intended to provide.

[0005]

In order to achieve the above object, a control device for a continuously variable transmission according to a first aspect of the present invention selects a corresponding shift pattern from a plurality of shift patterns according to a running state of a vehicle. And in the control device of the continuously variable transmission configured to control the speed ratio of the continuously variable transmission connected to the rotary drive source according to the selected shift pattern, a start state detection unit that detects a start state of the vehicle, A pattern selection detecting means for detecting that a limited gear shift pattern in which a maximum gear ratio side is limited to a minimum gear ratio side with respect to a gear shift pattern during normal traveling, and a starting state of the vehicle are detected by the starting state detecting means. and detects that said pattern selection detecting means with the restriction shift pattern is selected, varying further the limited
The maximum gear ratio side is limited to the minimum gear ratio side by the speed pattern.
If the deviation between the set target gear ratio and the actual gear ratio is
At one time, an output reduction means for reducing the output of the rotary drive source.

According to the first aspect of the present invention, the starting state detecting means detects the starting state of the vehicle, and the pattern selection detecting means sets the maximum gear ratio side to the minimum gear ratio side with respect to the shift pattern during normal running. detects that restricted restricted shift pattern is selected, further the limited transmission path
The maximum gear ratio side is limited to the minimum gear ratio side by the turn
The deviation between the target speed ratio and the actual speed ratio is greater than or equal to a predetermined value
In some cases, the output of the rotary drive source that transmits the rotary drive force to the continuously variable transmission is reduced by the output reduction unit. For this reason, even when the continuously variable transmission is controlled to the maximum gear ratio when the vehicle starts,
The output torque of the continuously variable transmission can be suppressed, and the starting characteristics on a road surface with a low friction coefficient can be improved. Ma
Also, when the vehicle starts, the deviation between the target gear ratio and the actual gear ratio
When the difference decreases, the output reduction state of the rotary drive source is released.
It is.

A control device for a continuously variable transmission according to a second aspect is characterized in that, in the first aspect, the limited shift pattern is a shift pattern for traveling on a road with a low friction coefficient.

In the invention according to the second aspect, the limited speed change pattern is a speed change pattern for traveling on a road with a low coefficient of friction, so that the first to second speeds in the automatic transmission when the vehicle starts moving.
The speed ratio corresponding to the speed is removed, and an optimum speed ratio for starting on a road surface with a low friction coefficient can be obtained.

Further, a control device for a continuously variable transmission according to a third aspect is characterized in that, in the invention of the first or second aspect, the selection of the limited shift pattern is performed by a selection switch.

According to the third aspect of the present invention, since the selection of the limited speed change pattern is performed by the selection switch, the selection can be easily performed.

According to a fourth aspect of the present invention, in the control device for a continuously variable transmission according to any one of the first to third aspects of the present invention, the output reducing means includes a throttle opening and a vehicle speed.
Output reduction amount based on the calculated output reduction amount.
Is characterized in that has been configured to control the output of the rotary drive source are.

Further, according to a fourth aspect of the present invention, in the control device for a continuously variable transmission according to any one of the first to third aspects, the output reduction means includes an output reduction amount based on a throttle opening and a vehicle speed. Is calculated, and the output of the rotary drive source is controlled based on the calculated output reduction amount.

According to the fourth aspect of the present invention, since the output reduction amount is calculated based on the throttle opening and the vehicle speed, it is possible to calculate the output reduction amount according to the running state of the vehicle.

According to a fifth aspect of the present invention, in the control device for a continuously variable transmission according to any one of the first to fourth aspects, the output reduction means reduces the output reduction amount based on a throttle opening and a vehicle speed. It is characterized in that the calculated output reduction amount is corrected in accordance with the deviation between the target speed ratio calculated based on the limited speed change pattern and the actual speed ratio.

According to the fifth aspect of the present invention, the output reduction amount calculated based on the throttle opening and the vehicle speed is corrected according to the actual shift state, so that the output reduction amount can be continuously changed. it can.

Furthermore, the control device for a continuously variable transmission according to claim 6, wherein the output reduction means, the output reduction amount so that the smaller value in accordance with the deviation becomes small and the actual speed ratio and the target gear ratio It is characterized in that it is configured to correct.

In the invention according to claim 6 , the deviation between the target gear ratio and the actual gear ratio increases when the vehicle starts on a road surface with a low friction coefficient, so that the output reduction amount also increases and the vehicle starts gently. Thereafter, as the deviation between the target speed ratio and the actual speed ratio decreases, the output reduction amount also decreases,
Ensure acceleration performance.

[0018]

According to the control device for a continuously variable transmission according to the first aspect, when the vehicle is started to travel on a road surface with a low friction coefficient, the maximum gear ratio is set to the minimum gear ratio with respect to the gearshift pattern during normal traveling. When the limited speed change pattern limited to the ratio side is selected, the maximum speed ratio
Deviation between target gear ratio limited to gear ratio and actual gear ratio
When is greater than or equal to a predetermined value, the output of the rotary drive source that transmits the rotary drive force to the continuously variable transmission is reduced,
Even if the continuously variable transmission is controlled to the maximum gear ratio at the time of starting the vehicle, the output torque of the continuously variable transmission is suppressed, so that the starting characteristic does not occur when starting on a low friction coefficient surface without slipping. Can be improved and the vehicle
Starts, and the deviation between the target gear ratio and the actual gear ratio is small.
When the output power of the rotary drive source is
In, effect that Ru can be secured subsequent acceleration performance.

According to the control device for a continuously variable transmission according to the second aspect, the limited speed change pattern is a speed change pattern for traveling on a road surface with a low friction coefficient. Is eliminated, and an effect is obtained that an optimal speed ratio for starting on a road surface with a low friction coefficient can be obtained.

Further, according to the control device for the continuously variable transmission according to the third aspect, since the selection of the limited speed change pattern is performed by the selection switch, an effect is obtained that the selection can be easily performed.

[0021]

Further, according to the control device for the continuously variable transmission according to the fourth aspect , the output reduction amount is calculated based on the throttle opening and the vehicle speed, so that the output reduction amount according to the running state of the vehicle is calculated. It is possible to obtain the effect that the vehicle can be smoothly started on the low friction coefficient surface.

Further, according to the control device for a continuously variable transmission according to the fifth aspect , the output reduction amount calculated based on the throttle opening and the vehicle speed is corrected according to the actual shift condition, so that the output reduction amount is obtained. Can be continuously changed, and it is possible to reliably prevent the driver from feeling uncomfortable.

Further, according to the control device for a continuously variable transmission according to the sixth aspect, the deviation between the target speed ratio and the actual speed ratio becomes large when the vehicle starts on a road surface with a low friction coefficient, so that the output reduction amount is also large. As the deviation between the target gear ratio and the actual gear ratio increases, the output reduction amount also decreases, and the effect of securing the acceleration performance according to the actual gear condition can be obtained. Can be

[0025]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram showing a first embodiment when the present invention is applied to a toroidal-type continuously variable transmission.

In FIG. 1, reference numeral 1 denotes an engine as a rotary drive source. A rotary drive force output from the engine 1 is input to a forward / reverse switching mechanism 4 via a torque converter 2, and the forward / reverse switching mechanism is provided. 4 outputs a driving force that rotates forward during forward movement and reversely rotates during reverse movement to the continuously variable transmission 5, and outputs the output of the continuously variable transmission 5 through the final reduction gear 6 to the rear wheels 7 serving as driving wheels. Is transmitted to Note that a fluid coupling may be used for the torque converter 2.

Here, as shown in FIG. 1, the continuously variable transmission 5 has input disks 11 and 12 which rotate integrally with the rotation shaft of the forward / reverse switching mechanism 4, and the input disks 11 and 12
The output disk 13 and the input disk 11
A pair of transmission rollers 15 provided between the output disk 13 and transmitting the rotational force therebetween, and a pair of transmission rollers 16 provided between the input disk 12 and the output disk 13 and transmitting the rotational force therebetween. I have at least.

Here, the contact surfaces between the input disks 11, 12 and the output disk 13 and the transmission rollers 15, 16 are formed as toroidal surfaces, and the transmission rollers 15, 16 are tilted with respect to the input disks 11, 12 and the output disk 13. By changing the angle, the rotation speed ratio between the input disks 11, 12 and the output disk 13 can be continuously changed.

The tilt angles of the transmission rollers 15, 16 with respect to the input disks 11, 12 and the output disk 13 are controlled by a hydraulic control device 20. As shown in FIG. 2, the hydraulic control device 20 includes a shift control valve 21 having a spool 21b slidably disposed in a valve body 21a, and a rack and pinion mechanism for shifting the spool 21b of the shift control valve 21. And a stepping motor 22, which is moved via a gear, and one of the piston rods
A hydraulic cylinder 23 connected to a rotation shaft of a support mechanism 17 for rotatably supporting the hydraulic cylinder 23, a precess cam 24 having a precess cam surface attached to the tip of the other piston rod of the hydraulic cylinder 23, and one end of the precess cam 24. An L-shaped link 25 is provided which engages with the cam surface and the other end of which engages with a projecting piece 21 c formed on the valve body 21 a of the transmission control valve 21.

The input port Ps of the transmission control valve 21
Is supplied with a line pressure PL from a line pressure regulating circuit (not shown), and input / output ports Po1 and Po2 are connected to pressure chambers 23b and 23c defined by a piston 23a of a hydraulic cylinder 23 via hydraulic piping, respectively. Drain port P
_D is connected to the tank. 27 is the valve body 2
This is a return spring that returns 1a to a neutral position.

Therefore, the spool 21b of the control valve 21 moves to the right in response to, for example, clockwise rotation of the step motor 22, whereby a predetermined line pressure PL is applied to the pressure chamber 23b of the hydraulic cylinder 23 via the input / output port Po1. While being supplied, the pressure oil in the pressure chamber 23c is returned to the tank via the input / output port Po2 and the drain port Pd. Therefore, the piston 23a moves downward, and the support mechanism 17 supporting the transmission roller 15 is moved downward from the neutral position.

For this reason, the precess cam 24 is also moved downward, so that the control valve 2 is connected via the L-shaped link 25.
When the first valve body 21a moves to the right, the input / output port P
o1 and Po2 are closed, and at the same time, the transmission roller 1
5 and 16 start tilting, so that the precess cam 2
4 rotates, and the valve body 21a is further moved to the right in response to this, and the line pressure PL is applied to the input / output port Po2 in the opposite manner.
Is supplied, the support mechanism 17 is returned to the neutral position, and the precess cam 24 is raised and the valve body 2
1a moves to the left, the input / output ports Po1 and Po2 are closed, and the tilting angles of the transmission rollers 15 and 16 are
The angle is changed by an angle corresponding to the number of steps of 2.

When the step motor 22 is driven and controlled by the shift control controller 35, the tilt angle of the transmission rollers 15, 16 with respect to each input / output disk changes in accordance with the number of steps of the step motor 22. The number of steps of the step motor 22 and the gear ratio uniquely correspond.

On the other hand, the vehicle is constituted by a rotary potentiometer or the like,
A throttle opening sensor (throttle opening detecting means) 41 for detecting O; an input shaft speed sensor 4 for detecting the speed of the input disk 11 of the toroidal type continuously variable transmission 5
2. An output shaft rotation speed sensor 43 for detecting the rotation speed of the output disk 13, and a select signal FD when a D range, which is a normal traveling range, is selected by a select lever (not shown).
Selector switch 44 that outputs the logical value “1”
A snow mode switch 45 that turns on a switch signal SW _SNOW when a snow mode instructing a snow mode running pattern for a low friction road surface such as a snowy road or a sandy road is selected.
And at least an engine speed sensor 46 for detecting the number of revolutions of the output shaft of the engine 1, and these are provided at appropriate places.

The throttle opening sensor 41 includes:
The throttle opening of the engine 1 is detected as a voltage signal,
When the accelerator pedal depression amount is "0", that is, when the equivalent throttle opening is in the fully closed state, the minimum value TVO _MIN is set, and the accelerator pedal depression amount is the maximum, that is, the throttle equivalent. where opening is fully opened as the maximum value TVO _MAX, analog signal TVO which to example 7 divided according to the throttle opening degree between these minimum TVO _MIN and the maximum value TVO _MAX is configured to output .

The speed control controller 35
Is a microcomputer 36 for performing arithmetic processing for speed ratio control and other speed change function control, which will be described later, and a motor drive circuit 3 for driving the step motor 22.
7 is provided.

The microcomputer 36 includes an input interface circuit 36a having an A / D conversion function for reading signals from the sensors, and an arithmetic processing unit 36b including a microprocessor unit MPU and the like.
A storage device 36c having a ROM, a RAM, and the like;
An output interface circuit 36d having an A-conversion function and the like.

Then, the microcomputer 36
Is a calculation process for a gear ratio control described later, for example.
Therefore, the throttle opening from the throttle opening sensor 41 is
Degree TVO and output shaft speed from output speed sensor 43
Vehicle speed V calculated based on No _SP, D range is selected
Or not, and whether the snow mode is selected
Target input rotation to be achieved by the continuously variable transmission based on
The number of turns is calculated, and based on this, the toroidal continuously variable transmission
5 to calculate and set the gear ratio C to be achieved,
Drive the stepper motor 21 necessary to achieve
Motor control signal S for_MIs generated, and the motor driving circuit 3
7, and will be described later when starting in the snow mode.
To the engine controller 50 that controls the engine 1
In response, a torque down request is made.

The motor drive circuit 37 outputs the motor control signal S _M output from the microcomputer 36 to
The signal is converted into a drive signal for the step motor 22 and output.
Further, the engine 1 has an engine speed, an intake air amount,
Intake air temperature, throttle opening, vehicle speed, engine water temperature,
The ignition timing, the fuel injection amount, and the like are controlled by an engine controller 50 to which a signal or the like from a brake switch is input, and the controller 50 provides a torque-down permission signal that is turned on when torque-down is possible. the ST _Y sends out to the shift control controller 35, when a torque down request signal ST _C from the shift control controller 35 is inputted, reads the torque reduction amount TD input from the shift control controller 35, the The ignition timing correction amount and the fuel injection correction amount are calculated based on the torque reduction amount, and the ignition timing and the fuel injection amount are controlled based on these correction amounts.

Next, the gear ratio control processing executed by the arithmetic processing unit 36b of the microcomputer 36 will be described with reference to the flowchart shown in FIG. This arithmetic processing is executed by a timer interrupt every sampling period of, for example, about 10 msec.

The speed ratio control process is performed, for example, for 10 msec.
This is executed as a timer interrupt process for each c. First, in step S1, the throttle opening TVO from the throttle opening sensor 41, the engine speed Ne from the engine speed sensor 46, and the input from the input shaft speed sensor 42. Shaft rotation speed Nt, output shaft rotation speed N from output shaft rotation speed sensor 43
o, switch signal S from snow mode switch 45
W, selector position signal FD from selector switch 44
Read.

Next, the process proceeds to step S2, where the output shaft
From the rotational speed No, the vehicle speed V is calculated based on the following equation (1)._SPCalculate
You. Note that A in the equation is a conversion coefficient. V_SP= No × A (1) Then, the process proceeds to step S6, where the vehicle speed V_SPWill be described later
Maximum gear ratio C in gear shift pattern_MAXTo the characteristic line
On the other hand, when the throttle opening TVO is "0"
Vehicle speed threshold value V set to the vehicle speed at the separation point from the line_0NLess than
It is determined whether or not there is_SP<V_0NIf
And then proceeds to step S7.
As a result, the target speed ratio Ct and the actual speed ratio Cp are normally changed.
Speed ratio C in speed pattern_MAXAfter setting together
The process proceeds to step S12 to be described _SP≧ V_0NWhen
To step S8.

[0043] In step S8, the vehicle speed V _SP and with reference to the normal mode shift pattern shown in FIG. 5 calculates a target input rotational speed TN _t the throttle opening TVO based on which the final target rotational speed Ni Set as ₀ .

[0044] Here, the normal mode shift pattern shown in FIG. 5, the ordinate abscissa the vehicle speed V _SP, the target input shaft rotational speed TNT, and overall control map of a normal shift pattern of the throttle opening TVO as a parameter A straight line that is equivalent and has a constant slope passing through the origin may be considered as having a constant speed ratio. For example, a straight line having the largest slope in the entire region of the shift pattern has the largest reduction ratio of the entire vehicle, that is, the maximum gear ratio C _MAX, and a straight line having the smallest slope has the smallest reduction ratio, that is, the minimum gear ratio. Ratio C _MIN
Is represented. Then, even comparable vehicle speed V _SP, depression amount is large throttle opening TV of the accelerator pedal
When O is large, for example, an acceleration force is required, or a load required for the engine due to a traveling load such as an uphill road or a head wind resistance is large, so that the engine rotation speed is increased to increase the output torque. Need to
Therefore, using the throttle opening TVO detected by the throttle opening sensor 41 as a parameter, the target input shaft speed TNt is set to be larger as the throttle opening TVO becomes larger. In a region where the vehicle speed _VSP is smaller than a certain speed ratio control start threshold, the speed ratio is set to the maximum speed ratio _CMAX .

Next, the process proceeds to step S9, where a time constant Kr is set according to, for example, the vehicle characteristics. The time constant Kr is a weighting factor indicating how much the first-order lag target rotation speed Ni ₁ (k−1) described later is reflected on the attained target rotation speed Ni ₀ , and is set to a value satisfying 0 <Kr <1. You. In addition,
Time constant Kr is also a fixed value, may be reduced to "0" to "1" in response to an increase in the vehicle speed when the vehicle speed V _SP is equal to or larger than a predetermined vehicle speed.

Next, the process proceeds to step S10, where the first-order lag target rotation speed Ni ₁ (k) is calculated based on the following equation (2). Ni ₁ (k) = [Ni ₀ + Ni ₁ (k−1) × Kr] / (Kr + 1) (2) where Ni ₁ (k−1) is a predetermined memory at the time of the previous execution of the shift control process. This is the primary delay target rotation speed at the time of the previous calculation stored in the area.

Next, the routine proceeds to step S11, where the target speed ratio is calculated according to the following equation (3) based on the primary delay target rotation speed Ni ₁ (k) and the output shaft rotation speed No calculated in step S10. Calculate Ct.

Ct = Ni ₁ (k) / No (3) Then, the process proceeds to step S12, where it is determined whether or not the switch signal SW of the snow mode switch 45 is on, and the switch is off. Sometimes, the process proceeds to step S13 to set the maximum speed ratio C _MAX during normal running as the maximum speed ratio limit value C _MAXL , and then _proceeds to step S15. Maximum speed ratio C _MAX during normal running as value C _MAXL
After setting the maximum speed ratio C _MAX 'corresponding to, for example, the second speed of the smaller automatic transmission, the process proceeds to step S15.

In step S15, step S7 or S
Maximum gear ratio at which the target gear ratio Ct calculated in 11 is set
Limit value C_MAXLIt is determined whether or not Ct ≧ C_MAXL
, The process proceeds to step S16 and the target gear ratio C
The maximum gear ratio limit value C as t _MAXLAfter setting
The process proceeds to S17, and Ct <C_MAXLIf it is
Then, control goes to a step S17.

[0050] At step S17, determines whether or not the target gear ratio Ct is less than or equal to the minimum speed ratio C _MIN, Ct ≦ C
_{If MIN} , the process proceeds to step S18, where the minimum speed ratio C _MIN is set as the target speed ratio Ct, and then the process proceeds to step S19. If Ct>, the process directly proceeds to step S19.

In step S19, a step motor control process for calculating and outputting a target number of steps for driving the step motor 22 based on the set target gear ratio Ct is executed, and the process is terminated. Return to the main program.

In the step motor control process, the control speed is defined because the step motor 22 cannot instantaneously achieve the target position. As shown in the flowchart of FIG. 4, first, at step S20, Based on the engine speed Ne and the throttle opening TVO, FIG.
The engine torque Te is calculated from a control map showing the correspondence between the engine speed Ne and the engine torque Te using the throttle opening TVO as a parameter as shown in FIG. And
This engine torque Te and the torque converter ratio t
From (e), the estimated input torque Tin of the continuously variable transmission 5 is calculated according to the following equation (4). It should be noted that the torque converter ratio t (e) is based on the input shaft speed Nt and the engine speed N
Based on the speed ratio e obtained from E and the following equation (5), the speed ratio is calculated with reference to a torque ratio map shown in FIG.

Tin = Te × t (e) (4) e = Nt / Ne (5) Next, in step S21, the target gear ratio set in the processing described above with reference to the control map of FIG. Based on Ct and the estimated input torque Tin, a torque shift compensation speed ratio Ca is set as a feedforward speed ratio in consideration of torque shift compensation.

Next, the process proceeds to step S22, where the current actual gear ratio Cp (= Nt / Nt) is obtained from the input shaft speed Nt from the input shaft speed sensor 42 and the output shaft speed No from the output shaft speed sensor 43. No) is calculated. Here, in a low vehicle speed state where the output shaft rotation speed No is small, the maximum gear ratio C _MAX
Is set as the actual gear ratio Cp.

Next, the routine proceeds to step S23, where the deviation ΔC between the target speed ratio Ct and the actual speed ratio Cp (= Ct−C
The feedback correction speed ratio Cf is calculated by multiplying p) by the feedback gain Kf.

Next, the routine proceeds to step S24, where the actual target gear ratio C ^* (= Ca + Cf) is calculated by adding the feedback correction gear ratio Cf to the feedforward gear ratio that becomes the torque shift compensation gear ratio Ca.

[0057] Then, the process proceeds to step S25, corresponding to the actual target speed ratio C ^*, the actual target step number STP ^* is the step number of the step motor 22, shown in FIG. 9, the actual target speed ratio C ^* And the number of steps STP of the step motor 22 from the control map.

Next, the process proceeds to step S26 to determine whether or not the actual target step number STP ^* obtained in step S25 is smaller than the current step number STP _NOW of the step motor 22. And the current step number STP
_{If the} actual target step number STP ^* is not smaller than _NOW (STP ^* ≧ STP _NOW ), the process proceeds to step S27, and the unit step amount ΔSTP is changed to the current step number S
The temporary target step number STP 'is calculated by adding to TP _NOW .

[0059] Then, the process proceeds to step S28, 'determines whether is greater than the actual target step number STP ^*, temporary target step number STP' temporary target step number STP than the actual target step number STP ^* If larger, the process proceeds to step S29, sets the actual target step number STP ^* as a motor control signal S _M. And step S
30 proceeds to, and outputs the motor control signal S _M to the motor drive circuit 32, returns to the main program terminates the processing.

On the other hand, if the provisional target step number STP 'is not larger than the actual target step number STP ^* (STP'≤STP ^* ) in the process of step S28, the process proceeds to step S28.
31 proceeds to transitions from set the temporary target step number STP 'as a motor control signal S _M to the step S30.

The current step is executed in the process of step S26.
STP_NOWIs the actual target number of steps STP^*Larger than
If not, the process proceeds to step S32 and the current step number S
TP _NOWIs subtracted from the unit step amount ΔSTP from
The target step number STP 'is calculated. Then, step S
33, and the number of temporary target steps STP 'is
Step number STP^*Is smaller than ST
P '<STP^*If not, proceed to step S34.
Then, the provisional target step number STP 'is set to the motor control signal S_M
Then, the process proceeds to step S30.

On the other hand, in the process of step S33, if the provisional target step number STP 'is smaller than the actual target step number STP ^* (STP'<STP ^* ), the processing proceeds to step S33.
Move to 29.

In the processing of FIGS. 3 and 4, the processing of steps S6 to S11 constitutes a target speed ratio calculating means.
The processing of steps S12 to S14 constitutes a pattern switching means, the processing of steps S20 and S21 constitutes a torque shift compensating means, the processing of steps S22 to S24 constitutes a feedback control means, and steps S26 to S3
The processing of 0 constitutes the step motor control means.

Further, the arithmetic processing unit 36b of the microcomputer 36 executes the torque down request processing shown in FIG. 10 by a timer interruption processing every predetermined time (for example, 10 msec).

In this torque-down request processing, first,
In step S41, the input from the engine controller 50
Torque down permission signal TD_YIs on
The torque down permission signal ST_YIs off
When there is, move to step S42, and
Torque-down request signal ST to controller 50 _C
Is set to the off state, and then the process proceeds to step S43.
Set the torque down amount TD to “0”, and
Then, the process proceeds to step S44, where_Cas well as
The required torque reduction amount TD is stored in the engine controller 50.
Timer processing after performing output processing to output to
And returns to the predetermined main program.

[0066] On the other hand, if the decision result in the step S41 the torque down permission signal ST _Y is turned on, the process proceeds to step S45, the switch signal SW snow mode switch 45 is determined whether the ON state When it is off, it is determined that the mode is the normal mode, and the process proceeds to step S42, and when it is on, the process proceeds to step S46.

[0067] In the step S46, it determines whether or not the throttle opening detection value TVO is preset predetermined setting value TVO _S (e.g. 3/8) or more, TVO <TV
When it is O _S, it is determined that a slow acceleration state shifts to the step S42, when it is TVO ≧ TVO _S, it is determined that the rapid acceleration state shifts to step S47.

[0068] In the step S47, the high speed running state when it is determined whether the low vehicle speed range including low vehicle speed threshold V _TH less stopped state where the vehicle speed V _SP is preset, a V _SP> V _TH Therefore, it is determined that the torque down control is not required, and the process proceeds to step S42, where V _SP ≦ V _TH
If it is, the process moves to step S48.

In step S48, the actual target gear ratio Ct and the actual gear ratio C _P calculated in the gear shift control process of FIG.
It is determined whether or not the absolute value of the gear ratio deviation ΔC, which is the deviation of the gear ratio, is equal to or greater than a preset value ΔC _S , and | ΔC | <ΔC
When it is _S , it has reached the actual target gear ratio Ct, it is determined that there is no need for torque down control, and the routine proceeds to step S42. When | ΔC | ≧ ΔC _S , the necessity of torque down control is high. It is determined that there is, and the process proceeds to step S49.

In this step S49, the torque-down request signal ST _C to the engine controller 50 is set to the ON state, and then the process proceeds to step S50.
Storage device the throttle opening TVO and the vehicle speed V _SP based on 3
The torque down amount TD is calculated with reference to the torque down amount control map shown in FIG. 11 stored in advance in FIG. 6c, and after setting this, the process proceeds to step S44.

[0071] Here, torque down amount control map, as shown in FIG. 11, the required torque reduction amount TD regardless of the vehicle speed V _SP is set to 0% in the low throttle opening the idle switch is turned on, Throttle opening TVO
Increases the required torque reduction amount TD as larger but this required torque reduction amount TD is set so as to decrease by the increase in the vehicle speed V _SP, 0% irrespective of the throttle opening TVO is equal to or greater than the set vehicle speed V _TH described above Is set to

In the torque down request processing of FIG. 10, the processing of step S45 corresponds to the pattern selection detecting means, and the processing of steps S46 to S48 corresponds to the starting state detecting means.

The engine controller 50 performs ignition timing control and fuel injection amount control in accordance with a main program.
The torque-down control process shown in FIG.
msec) as a timer interrupt process.

In the torque down control process, first, in step S61, it is determined whether or not the torque down request signal ST _C is on. If the torque down request signal ST _C is on, the process proceeds to step S62, where the shift control controller 35
The required torque reduction amount TD input from the CPU is read, and based on this, the ignition timing calculated in the ignition timing control process in the main program and the ignition timing correction amount and the fuel injection amount for the fuel injection amount calculated in the fuel injection amount control process The correction amount is calculated, and then the process proceeds to step S63, in which the calculated ignition timing correction amount and fuel injection correction amount are updated and stored in a predetermined storage area of a storage device that can be referred to from the main program, and then the timer interrupt processing is terminated. To return to the predetermined main program.

On the other hand, if the result of determination in step S61 is that the torque-down request signal TD is in the OFF state, the process proceeds to step S64, where both the ignition timing correction amount and the fuel correction amount are set to "0". Move to step S63.

Here, the torque-down request processing in FIG. 10 and the torque-down control processing in FIG. 12 correspond to output reduction means. Therefore, the vehicle is stopped when the select position has selected the parking range or the neutral range on a high friction coefficient road surface such as a dry asphalt road surface or a concrete road surface where a sufficient friction coefficient state is maintained between the tires. It is assumed that the snow mode switch 45 is kept off.

If the select position is set to the D range suitable for normal traveling from this stopped state, the vehicle speed _VSP is "0" when the shift control process of FIG. 3 is executed.
Both the target speed ratio Ct and the actual speed ratio Cp are the maximum speed ratio C
_Since the snow mode switch 45 is set to _MAX (step S7) and the snow mode switch 45 is off, the maximum speed ratio C _MAX is maintained as it is as the target speed ratio Ct (step S7).
14 to S17).

Then, after the torque shift compensation is performed in steps S20 and S21 to calculate the torque shift compensation speed ratio Ca which becomes the feedforward speed ratio, the feedback correction speed ratio Cf is calculated (step S23).
Since the target speed ratio Ct matches the actual speed ratio Cp, the feedback correction speed ratio Cf becomes “0”, and the torque shift compensation speed ratio Ca is set as the actual target speed ratio C ^* .

An actual target step number STP ^* corresponding to the actual target gear ratio C ^* is set (step S25), and the step motor 22 is controlled so as to control the continuously variable transmission 5 to the maximum gear ratio _CMAX. .

At this time, the continuously variable transmission 5 shifts to step S7 at the end of the previous running, so that the maximum speed ratio C
Since it is controlled to _MAX , the actual target gear ratio and the actual gear ratio match.

[0081] On the other hand, in the torque-down request processing of FIG. 10, the torque down permission signal ST _Y from the engine controller 50 is assumed to be input, the process proceeds from step S41 to step S42, the snow mode switch 45 Since it is off, step S42
To set the torque-down request signal ST _C to the off state, and then in step S43, the required torque-down amount T
After setting D to “0”, the process proceeds to step S44,
Torque reduction request signal ST _C and required torque reduction amount T
D is sent to the engine controller 50.

For this reason, the engine controller 50 executes the torque-down control process of FIG. 12, so that the torque-down request signal ST _C is in the OFF state in step S62. The correction amount and the fuel injection correction amount are both set to “0” and updated and stored in a predetermined storage area of the storage device.

For this reason, when the ignition timing control processing and the fuel injection quantity control processing in the main program refer to the predetermined storage area of the storage device, the ignition timing correction quantity and the fuel injection correction quantity are both "0". Normal ignition timing and fuel injection amount control are continued without making a correction based on a torque down request, and a rotational driving force of an output torque sufficient to start the vehicle on a road surface with a high friction coefficient is updated via the torque converter 2 in advance. This is transmitted to the switching mechanism 4.

In this state, when the D range, which is the normal traveling range, is selected with the select lever, the forward rotation driving force is transmitted from the forward / reverse switching mechanism 4 to the input disk 1 of the continuously variable transmission 5.
1,12 is transmitted, this is transmitted is transmitted to the output disk 13 at the maximum speed ratio C _MAX to wheel 9 after the drive wheel via a final reduction gear 8 vehicle to start.

[0085] When the vehicle speed V _SP reaches the predetermined vehicle speed V _0N, the shift control process in FIG. 3, results in a transition from step S6 to step S8, the vehicle speed V _SP at that time
The target input rotational speed Ni ₀ is calculated based on the normal mode shift pattern of FIG. 5 based on the throttle opening TVO and the target opening speed TVO, and the target speed ratio Ct is calculated based on the target input speed Ni _0. Is driven so that the tilt angles of the transmission rollers 15 and 16 of the continuously variable transmission 5 match the actual target gear ratio C ^* .

After that, when the accelerator pedal is released and the brake pedal is depressed in place of this to bring the brake state, the throttle opening TVO becomes 0/8 indicating the fully closed state, and the normal mode shown in FIG. Following the characteristic line corresponding to the minimum speed ratio C _MIN of the speed change pattern, when the vehicle speed V _SP falls below the set vehicle speed V _{HN, the} speed is gradually shifted to the maximum speed ratio C _MAX , and when the vehicle speed V _SP reaches a predetermined vehicle speed V _0N , the maximum speed ratio C is reached. _MAX next, when the subsequent further vehicle speed V _SP is lowered, in the shift control process in FIG. 3, the process proceeds to step S7, the target gear ratio Ct vehicle is stopped from being fixed at the maximum speed ratio C _MAX.

On the other hand, when the vehicle is stopped on a low friction coefficient road surface on which a sufficient friction coefficient state cannot be obtained between the vehicle and a tire such as wet asphalt road surface or icy snow road surface, the vehicle starts smoothly. The driver sets the snow mode switch 4
When 5 was set to the ON state, when the shift control process in FIG. 3 has been executed, the target gear ratio Ct is set to the maximum speed ratio C _MAX once in step S7, step S12
Since the switch signal SW of the snow mode switch 45 is in the ON state, the process proceeds to step S14, and the limited maximum speed ratio C _MAX 'corresponding to the second speed in the automatic transmission is set as the maximum speed ratio limit value C _MAXL. As a result, the target speed ratio Ct is limited to the limited maximum speed ratio C _MAX 'in step S16 after step S15.

Therefore, the normal mode gearshift pattern of FIG. 5 is selected in the same manner as the snowmode gearshift pattern limited between the limited maximum gear ratio C _MAX ′ shown by the broken line and the minimum gear ratio C _MIN shown by the solid line. It is equivalent to

For this reason, the step motor 22 of the hydraulic control circuit 20 is controlled to the step number position corresponding to the limited maximum gear ratio C _MAX '. At this time, the input disk 11 of the continuously variable transmission 5 is controlled. , 12 are not transmitted, the tilt angles of the transmission rollers 15, 16 are not changed, and the maximum gear ratio _CMAX is maintained.

On the other hand, in the torque-down request processing of FIG.
Is in the ON state, so that steps S45 to S
The process moves to 46, the vehicle is in a stopped state, since not depressed the accelerator pedal, the throttle opening TVO is a "0", is smaller than the set value TVO _S,
Proceeding to step S42, the torque down request signal ST
_C continues the OFF state, and also in the torque down control process of FIG. 12, the state where both the ignition timing correction amount and the fuel injection correction amount are set to “0”.

In this state, when the D range, which is the normal travel range, is selected with the select lever, and the accelerator pedal is depressed to start the vehicle, the forward / reverse switching mechanism 4 outputs the forward rotation driving force. The power is transmitted to the input disks 11 and 12 of the step transmission 5 and is transmitted to the transmission rollers 1.
5 and 16 to the output disk 13.

However, the torque shown in FIG.
When the down request processing is executed, the throttle opening TV
O is the set value TVO_SAs described above, the process proceeds to step S47.
Since the vehicle shifts to the stopped state, V_SP<V_THTona
Therefore, the process proceeds to step S48, and the target
The gear ratio Ct is equal to the limited maximum gear ratio C_MAX′
The actual gear ratio C_MAXAnd these deviations Δ
The absolute value of C is the set value ΔC _SThat is all for step S49.
Move to

Therefore, the torque reduction request signal ST _C is set to the ON state, and the required torque is determined by referring to the torque reduction amount control map of FIG. 11 based on the vehicle speed V _SP and the throttle opening TVO at that time. The down amount TD is calculated. At this time, the calculated required torque reduction amount TD is
Since the vehicle speed V _SP is “0”, a value from 10% to 50% is selected according to the throttle opening TVO.

The torque-down request signal ST _C and the required torque-down amount TD are stored in the engine controller 50.
Sent to Therefore, the engine controller 50
Since the torque-down request signal ST _C is in the ON state, the ignition timing correction amount and the fuel injection correction amount that satisfy the torque-down amount TD are calculated based on the required torque-down amount TD, and are calculated by the storage device. By performing update storage in the storage area, when the ignition timing control processing and the fuel injection amount control processing in the main program are executed, the correction based on the ignition timing correction amount and the fuel injection correction amount updated and stored in the storage device is performed. As a result, the output torque of the engine 1 is reduced by an amount corresponding to the required torque reduction amount TD.

Therefore, the input disk 1 of the continuously variable transmission 5
When the driving torque of the rotational driving force transmitted to the transmissions 1 and 12 is reduced, the transmission rollers 15 and 1 of the continuously variable transmission 5 are reduced.
6 even maintains the tilt angle corresponding to the maximum speed ratio C _MAX, will be output torque of the continuously variable transmission 5 is inhibited, during the starting of the low friction coefficient road surface, rear wheels is a driving wheel Can be reliably suppressed, and smooth starting can be performed while ensuring steering stability.

Since the step motor 22 is controlled to the number of steps corresponding to the limited maximum gear ratio C _MAX 'corresponding to the second speed of the automatic transmission when the vehicle is stopped as described above, The line pressure PL is supplied to the pressure chamber 23b of the hydraulic cylinder 23,
When the transmission rollers 15, 16 of the continuously variable transmission 5 start rotating, the transmission rollers 15, 16 are quickly moved to the tilt angle corresponding to the limited maximum speed ratio C _MAX 'with high responsiveness. Will be.

[0097] For this reason, the output torque of the continuously variable transmission 5 is further suppressed.
Slip generated on the rear wheels that are the driving wheels can be reliably suppressed, and smooth starting can be performed while ensuring steering stability.

[0098] Thereafter, when the vehicle speed V _SP is equal to or higher than a predetermined vehicle speed V _0N, the target input revolution speed of the vehicle speed V _SP and the throttle opening TVO with reference to the snow mode shift pattern of broken lines shown in FIG. 5 on the basis of that time Ni ₀ is calculated, and based on this, the target gear ratio Ct is calculated. When the calculated target gear ratio Ct is larger than the limited maximum gear ratio C _MAX ′, the target gear ratio Ct is limited to the limited maximum gear ratio C _MAX ′, when less than the gear ratio C _MIN, by being limited to the minimum speed ratio C _MIN, it is possible to secure stable running is reliably prevented from causing slippage of the drive wheels in a low friction coefficient road surface.

On the other hand, the required torque reduction amount TD calculated in the torque reduction request processing of FIG. 10 gradually decreases as the vehicle speed _VSP increases, and accordingly, the output torque of the engine 1 gradually decreases. When the vehicle speed returns to the normal output torque and the vehicle speed V _SP reaches the set vehicle speed V _TH , the required torque reduction amount TD becomes “0” and the engine controller 50
The corrections in the ignition timing control process and the fuel injection amount control process of the main program in response to the torque down request in step S1 are released, and the control returns to the normal control state.

When the vehicle has been started and the vehicle is in the normal running state, and the absolute value of the deviation ΔC between the target speed ratio Ct and the actual speed ratio Cp becomes equal to or smaller than the set value ΔC _S , the process proceeds from step S48 to step S42. And the torque down request signal S
T _C is set to the off state, and then, in step S43, the required torque reduction amount TD is set to “0”, so that the correction by the torque reduction request in the engine controller 50 is canceled, and the output torque of the engine 1 is released. Is returned to the normal state.

[0102] Further, when starting of the vehicle, when the braking state depress the brake pedal, by the throttle opening TVO and the accelerator pedal is released is equal to or less than a predetermined value TVOS _S, Step S42 from Step S46
The process moves to, the torque down request signal ST _C while being controlled to the OFF state, is set to the torque down amount TD "0", the output torque of the engine 1 is returned to a normal torque value.

When the vehicle is running and the accelerator pedal is released and the vehicle is brought into a stopped state by the engine brake or the normal brake and the vehicle is shifted to a stop state, the minimum gear ratio C _MIN shown in FIG. 5 is traced. , Vehicle speed V _SP
When the vehicle speed becomes equal to or lower than the set vehicle speed V _HN , the speed ratio is gradually shifted to the maximum speed ratio C _MAX, and at the predetermined vehicle speed V _0S , the limited maximum speed ratio C
Reaching _MAX ', the subsequent further vehicle speed V _SP is lowered, the target speed ratio C in step S7 in the shift control process in FIG. 3
t is set to the maximum gear ratio C _MAX , but as long as the snow mode switch 45 is kept on, step S1
6, the target gear ratio Ct is limited to the limited maximum gear ratio C _MAX ′, so that the vehicle can be started at the limited maximum gear ratio C _MAX ′ at the time of restart, and stable without generating slip on the drive wheels. You can make a start.

When the vehicle is traveling on a road surface having a high friction coefficient from a road surface traveling on a road surface having a low friction coefficient,
By setting the snow mode switch 45 to the off state, in the shift control process of FIG.
Can be immediately switched to the normal mode shift pattern shown by the solid line, so that shift control corresponding to a road surface with a high friction coefficient can be performed.

Further, when the vehicle is stopped with the snow mode switch 45 turned on, the speed ratio is fixed to the limited maximum speed ratio C _MAX 'as described above. When the vehicle is running on a road surface with a high friction coefficient with the snow mode switch 45 turned off, the step motor 22 is moved to the step position corresponding to the maximum speed ratio C _MAX when the vehicle is stopped in the speed change control process of FIG.

Therefore, when the vehicle starts on a road surface with a high coefficient of friction, the rotational driving force is transmitted to the input disks 11, 12 of the continuously variable transmission 5, and the transmission rollers 15, 16 immediately start rotating. It is possible to quickly change the tilt angle corresponding to the limited maximum gear ratio C _MAX 'to the tilt angle corresponding to the maximum gear ratio C _MAX with high responsiveness and exhibit good starting characteristics on a road surface with a high friction coefficient. it can.

Next, a second embodiment of the present invention will be described with reference to FIGS. In the second embodiment, the required torque reduction amount TD calculated based on the throttle opening and the vehicle speed is changed to a gear ratio deviation | ΔC | which is an absolute value of a difference between the target gear ratio Ct and the actual gear ratio Cp. The correction is made accordingly.

In the second embodiment, the torque reduction request processing in the shift control controller 35 is performed as follows.
As shown in FIG. 13, FIG.
A step S51 of calculating the correction gain K based on the gear ratio deviation | ΔC | between steps S50 and S44 in the torque down request processing of 0, and the calculated correction gain K is multiplied by the torque down amount TD to obtain a request. It was treated in the same manner as FIG. 10 except that the the step S52 of calculating a torque reduction amount TD _C are added are denoted by the same step numbers and the corresponding process, and a detailed description thereof will be omitted this .

Here, the correction gain calculation processing in step S51 is based on the gear ratio deviation | ΔC |
The correction gain K is calculated with reference to the correction gain control map shown in FIG.

As shown in FIG. 14, the correction gain control map is formed as a characteristic diagram in which the abscissa indicates the speed ratio deviation | ΔC | and the ordinate indicates the correction gain, and the speed ratio deviation | ΔC | Is equal to the set value ΔC _S , the correction gain K is 0
%, And the parabolic characteristic curve L1 is set such that the correction gain K increases when the gear ratio deviation | ΔC | exceeds the set value ΔC _S.

According to the second embodiment, when the low friction coefficient road surface is started with the snow mode switch 45 turned on, the difference between the target speed ratio Ct and the actual speed ratio Cp is the same as at the start of starting. transmission ratio deviation | [Delta] C | when becomes a large value, correction gain K by is set to approximately 100%, the controller for the engine as the torque down amount TD is directly required torque reduction amount DT _C calculated in step S50 50, and the output torque of the engine 1 is reduced by an amount corresponding to the torque down amount TD.

Then, when the vehicle starts to move, the actual transmission ratio C is determined by the rotation of the transmission rollers 15 and 16 of the continuously variable transmission 5.
When p starts shifting toward the target gear ratio Ct, the difference | ΔC | between the two gradually decreases, and accordingly, in the torque-down request processing of FIG.
By correction gain K that is calculated is gradually smaller in, gradually become a smaller value the required torque reduction amount TD _C to the engine controller 50, for gradually normal output torque output torque of the engine 1 Increased.

The gear ratio deviation | ΔC | is equal to the set value ΔC
Rapid correction gain K toward the _S becomes closer to the 0%, rapidly demand torque reduction amount TD _C "0"
, The output torque of the engine 1 rapidly increases toward the normal output torque, and the speed ratio deviation | ΔC |
There shifts from step S48 becomes less than the set value [Delta] C _S in step S42, becomes the torque down request signal ST _C off, returning to the torque down control is stopped to the normal engine control state, the torque down amount Since TD is continuously reduced, a smooth torque reduction control can be performed without a sudden change in torque.

In the first embodiment, the throttle opening TVO is large, for example, at the time of sudden start.
When the torque down amount TD calculated in step S50 is large, in the above-described first embodiment, the target gear ratio C
Until the gear ratio deviation | ΔC |, which is the difference between the t and the actual gear ratio Cp, reaches the set value ΔC _S , the amount of torque reduction calculated by increasing the vehicle speed V _SP decreases. Is small, the decrease in the torque down amount TD is also small, and the speed ratio deviation | ΔC |
_{When S} reaches _S , the torque down amount TD may have a value larger than “0”, and this torque down amount TD becomes “0” at a stretch, so that the torque fluctuation of the output torque of the engine 1 is reduced. However, in the second embodiment, this problem can be solved.

In each of the above embodiments, the case where the half toroidal type continuously variable transmission 5 is applied as the continuously variable transmission has been described. However, the present invention is not limited to this, and the full toroidal type continuously variable transmission is not limited thereto. The present invention is also applicable to a belt-type continuously variable transmission in which a V-belt is stretched between a primary pulley and a secondary pulley.

In the above embodiment, the case where the valve body 21a and the spool 21b of the shift control valve 21 are relatively moved has been described. However, the present invention is not limited to this. By slidably inserting the sleeve and slidably arranging the spool in the sleeve, the sleeve can be displaced by the precess cam 24, whereby the same effect as described above can be obtained.

In each of the above embodiments, the case where the control unit is constructed by a microcomputer has been described. However, the present invention is not limited to this, and it is needless to say that electronic circuits such as arithmetic circuits may be combined. No.

Further, in the above embodiment, the case where the snow mode switch is applied as the pattern selection detecting means has been described. However, the present invention is not limited to this, and other selection detecting means such as a touch switch and a stick switch may be used. Can be applied.

Further, in each of the above embodiments,
Discusses vehicles with D range as normal driving range
As explained above, the maximum gear ratio is limited in addition to the D range.
Ratio C _MAX′ And the minimum gear ratio C
_MINLimit engine brake to a higher value
If you have a snow range,
Switch 45 is omitted, and a range switch is detected instead.
Detection means is provided as pattern selection detection means.
May be.

Further, in each of the above embodiments,
Although the case where the torque shift compensation is performed in steps S20 and S21 has been described, this can be omitted, and the open loop processing can be performed without the feedback control processing in steps S22 to S24.

In each of the above embodiments, when the snow mode switch 45 is in the ON state, the maximum gear ratio C _{MAX is set} in step S14 in the gear ratio control process of FIG.
However, when the snow mode switch 45 is on, the maximum speed ratio shown in FIG. 15 is changed to the maximum speed ratio shown in FIG. 15 instead of the normal mode shift pattern shown in FIG. compared to the normal mode shift pattern of, while being limited to a maximum speed ratio C _MAX 'corresponding to, for example, the second speed of the conventional automatic transmission, has been limited up to the target input shaft number TN _t to a value slightly lower select snow mode shift pattern, in accordance with the shift pattern may be calculated target input shaft rotational speed TN _t.

Further, in each of the above embodiments, the shift response can be improved by increasing the line pressure supplied to the shift control valve 21 when the vehicle starts when the snow mode switch 45 is on.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram illustrating an example of a control device for a continuously variable transmission according to the present invention.

FIG. 2 is a schematic configuration diagram of a hydraulic control device in FIG. 1;

FIG. 3 is a flowchart illustrating an example of a processing procedure of a shift control process in the microcomputer in FIG. 1;

FIG. 4 is a flowchart illustrating an example of a step motor control process of FIG. 3;

FIG. 5 is a diagram showing a control map showing a normal mode shift pattern showing a relationship between a vehicle speed and a target input rotation speed using a throttle opening as a parameter.

FIG. 6 is a diagram showing a torque ratio map showing a relationship between a speed ratio e and a torque converter ratio t (e).

FIG. 7 is a diagram showing a control map representing a correspondence between an engine speed Ne and an engine torque Te using a throttle opening TVO as a parameter.

FIG. 8 is a control map showing a correspondence between a target gear ratio Ct and an actual target gear ratio C ^{* using an} input torque Tin as a parameter.

FIG. 9 is a control map showing a correspondence between an actual target gear ratio C ^* and a step number STP of a step motor.

FIG. 10 is a flowchart illustrating an example of a torque-down request processing procedure in the microcomputer of FIG. 1;

FIG. 11 is an explanatory diagram showing a torque-down amount control map for calculating a required torque-down amount based on a vehicle speed and a throttle opening.

FIG. 12 is a flowchart illustrating an example of a torque-down control processing procedure in the engine controller of FIG. 1;

FIG. 13 is a flowchart illustrating an example of a torque-down request processing procedure in the microcomputer according to the second embodiment of the present invention.

FIG. 14 is an explanatory diagram showing a correction gain control map showing a relationship between a gear ratio deviation and a correction gain.

FIG. 15 is a characteristic diagram illustrating an example of a shift pattern for a snow mode.

FIG. 16 is a characteristic diagram showing a D range snow pattern in a conventional automatic transmission.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine 2 Torque converter 4 Forward / reverse switching mechanism 5 Toroidal-type continuously variable transmission 9 Driving wheel 11, 12 Input disk 13 Output disk 15, 16 Transmission roller 20 Hydraulic control device 21 Transmission control valve 35 Control unit 36 Motor drive circuit 41 Throttle Opening sensor 42 Input shaft speed sensor 43 Output shaft speed sensor 45 Snow mode switch 46 Engine speed sensor 50 Engine controller

Continuation of front page (56) References JP-A-8-218910 (JP, A) JP-A-8-158906 (JP, A) JP-A-3-99945 (JP, A) JP-A-2-144233 (JP) , A) JP-A-2-3734 (JP, A) JP-A-62-292536 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B60K 41/04-41/18 F02D 29/00-29/02

Claims (6)

(57) [Claims] 1. A speed change pattern selected from a plurality of speed change patterns according to a running state of a vehicle, and a speed ratio of a continuously variable transmission connected to a rotary drive source is controlled according to the selected speed change pattern. In the control device for a continuously variable transmission, a starting state detecting means for detecting a starting state of the vehicle and a limited speed change pattern in which a maximum speed ratio side is limited to a minimum speed ratio side with respect to a speed change pattern during normal running are selected and pattern selection detecting means for detecting that the said start detecting the starting state of the vehicle state detecting means, and detects that said pattern selection detecting means with the restriction shift pattern is selected, further
The maximum speed ratio side is the minimum speed due to the limited speed change pattern
The deviation between the target gear ratio limited to the ratio side and the actual gear ratio is
A control device for a continuously variable transmission , comprising: output reduction means for reducing the output of the rotary drive source when the output is equal to or greater than a predetermined value . 2. The speed change pattern according to claim 1, wherein the limited speed change pattern is a speed change pattern for running on a road surface with a low friction coefficient.
The control device for a continuously variable transmission according to any one of the preceding claims. 3. The control device for a continuously variable transmission according to claim 1, wherein the limit shift pattern is selected by a selection switch. 4. The method according to claim 1, wherein the output reducing means includes a throttle opening and a throttle opening.
The output reduction amount is calculated based on the vehicle speed and the vehicle speed.
Control device for a continuously variable transmission according to any one of claims 1 to 3, characterized in that has been configured to control the output of the rotary drive source based on the weight loss. 5. The target shift , wherein the output reduction means calculates an output reduction amount based on a throttle opening and a vehicle speed, and calculates the calculated output reduction amount based on a limited shift pattern.
The control device for a continuously variable transmission according to any one of claims 1 to 4, wherein correction is performed according to a deviation between the ratio and an actual speed ratio . 6. The output reduction means sets a target output reduction amount.
The smaller the deviation between the gear ratio and the actual gear ratio, the smaller
There value so as to correct control device for a continuously variable transmission according to claim 5 Symbol mounting, characterized in that it has been configured.