JP3048494B2 - Shift control method 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 shift control method for a continuously variable transmission, and more particularly to a shift control method for a continuously variable transmission capable of performing a shift control suitable for a driving operation and a running state of a vehicle.

[0002]

2. Description of the Related Art In a vehicle, a transmission is interposed between an internal combustion engine and driving wheels. In this transmission, the driving force of the drive wheels and the traveling speed are changed in accordance with the traveling conditions of the vehicle which change over a wide range, and the performance of the internal combustion engine is sufficiently exhibited. The transmission is formed between both pulley parts of a pulley having, for example, a fixed pulley part fixed to a rotating shaft and a movable pulley part attached to the rotating shaft so as to be able to approach and separate from the fixed pulley part. There is a continuously variable transmission that changes the groove width by hydraulic pressure to reduce or increase the radius of rotation of the belt wound around the pulley, transmits power, and changes the belt ratio (speed ratio).

[0003] Some continuous variable transmissions have a hydraulic clutch for interrupting power by hydraulic pressure. The hydraulic clutch is controlled in various control modes based on signals such as an engine speed and a carburetor throttle valve opening.

In the continuously variable transmission, for example, a shift control for adjusting a gear ratio so as to make the actual engine speed match the final target engine speed by, for example, adding transient correction to obtain the final target engine speed. There is. Rate limit control is a method for obtaining a final target engine speed by transiently correcting the target engine speed in a steady state. Rate limit control limits the amount of change in the final target engine speed per unit time. As the rate limit control, there is a transient control for performing the rate limit control with a value larger than a normal change amount and a control value. The transient control when the throttle opening sharply increases is the throttle transient control. The transient control at the time of the shift operation is the shift transient control.

As a control method of a continuously variable transmission for a vehicle, as disclosed in Japanese Patent Publication No. 4-28947, in a continuously variable transmission for a vehicle in which the speed ratio is continuously changed, a predetermined relation is set. A control target value is determined based on the actual acceleration operation amount, and the engine speed or speed ratio is controlled to follow the control target value, wherein the acceleration operation member of the vehicle is rapidly operated. In the transient state, a transient control target value that changes more slowly than the control target value and changes at least in relation to the operation speed of the accelerator pedal of the vehicle is set in place of the control target value.

[0006]

As a conventional transient control method for speed change control of a continuously variable transmission, a rate limit control is performed by using a difference between a target value in a steady state and an engine speed as a factor. Limit value).

[0007] As shown in FIG.
HR) from the rapid increase to the point A, that is, the engine speed (NE) is the engine speed trigger (NESPRU).
The throttle transient control is performed until the speed reaches.

Further, in the prior art, the final target engine speed (NESPRF) has a value considerably higher than the engine speed trigger (NESPRU) at the point A described above.

At this time, the engine speed (NE) is
Since the control is performed so as to be equal to the final target engine speed (NESPRF), the throttle transient control does not work extra as much as the final target engine speed (NESPRF) is larger than the engine speed trigger (NESPRU). However, there is a disadvantage that it is disadvantageous in practical use.

The engine speed (NE) is:
Since it constantly fluctuates, the conventional control method is easily affected by disturbance. For example,
As shown at point B in FIG. 18, when the engine speed (NE) temporarily drops due to disturbance or the like, the difference between the target engine speed (NESPR) in the steady state and the engine speed (NE) becomes large. , The limit value (R
ATUPN) becomes large, and the final target engine speed (NESPRF) temporarily increases suddenly.

[0011]

SUMMARY OF THE INVENTION Accordingly, in order to eliminate the above-mentioned disadvantages, the present invention is directed to a pulley portion comprising a fixed pulley portion and a movable pulley portion which is detachably attached to the fixed pulley portion. The rotation width of the belt wound around the two pulleys is increased or decreased by increasing or decreasing the groove width between the one piece by hydraulic pressure, and transient correction is made to the steady state target engine rotation speed calculated from the throttle opening map and the vehicle speed map. In the shift control method for a continuously variable transmission that performs shift control so that the actual engine speed matches the final target engine speed after the start, an engine speed trigger for the throttle opening is calculated from an engine speed trigger map, During transient correction of the steady-state target engine speed, the steady-state target engine speed is filtered and the The amount of change in the target engine speed is set by a limit value taking into account at least the previous final target engine speed, and the difference between the engine speed trigger and the final target engine speed or the steady-state target engine speed and the final target engine speed. Shift control is performed so as to change the limit value according to a difference from the engine rotation speed.

[0012]

According to the invention described above, the engine speed trigger for the throttle opening is calculated in advance from the engine speed trigger map, and when the steady-state target engine speed is transiently corrected, the steady-state target engine speed is reduced. In addition to performing the filtering process, the amount of change in the final target engine speed per unit time is set at least by a limit value that takes into account the last final target engine speed, and the difference between the engine speed trigger and the final target engine speed is calculated. Shift control is performed to change the limit value according to the difference between the target engine speed in the steady state and the final target engine speed.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings.

1 to 11 show an embodiment of the present invention. In FIG. 2, 2 is a continuously variable transmission, 4 is a belt, 6 is a driving pulley, 8 is a driving fixed pulley piece,
10 is a drive side movable pulley piece, 12 is a driven side pulley,
14 is a driven-side fixed pulley part, and 16 is a driven-side movable pulley part. As shown in FIG. 2, the driving pulley 6 includes a driving fixed pulley piece 8 that is fixed to a rotating shaft 18 that is rotated by a prime mover, and the rotating shaft that is movable in the axial direction of the rotating shaft 18 and cannot rotate. And a drive-side movable pulley piece 10 mounted on the drive pulley 18. In addition, the driven pulley 12
Has a configuration similar to that of the drive side pulley 6 and includes a driven side fixed pulley portion 14 and a driven side movable pulley portion 16.

A first housing 20 and a second housing 20 are attached to the movable pulley 10 and the movable pulley 16.
22 are respectively mounted on the first and second hydraulic chambers 2.
4 and 26 are respectively formed. The second hydraulic chamber 26 on the driven side
A pressing spring 28 for urging the driven-side movable pulley piece 16 toward the driven-side fixed pulley piece 14 is provided therein.
Is provided.

An oil pump 30 is provided at an end of the rotating shaft 18. The oil pump 30 supplies the oil in the oil pan 32 through an oil filter 34 to first and second oil passages 38 and 40 constituting a hydraulic circuit 36.
Is supplied to the first and second hydraulic chambers 24 and 26. In the middle of the first oil passage 38, a primary pressure control valve 44 as a speed change control valve constituting a pressure control means 42 for controlling a primary pressure as an input shaft sheave pressure is provided. A third oil passage 46 communicating with the first oil passage 38 closer to the oil pump 30 than the primary pressure control valve 44 applies a line pressure (generally, 5 to 25 ° / 〓 ² ) to a constant pressure (for example, 3 to 4).圧 / 〓 ² ) Constant pressure control valve 4
8 are provided. Further, the primary pressure control valve 44 includes:
A first three-way solenoid valve 52 for primary pressure control is connected via a fourth oil passage 50.

In the middle of the second oil passage 40,
A line pressure control valve 54 having a relief valve function of controlling a line pressure serving as a pump pressure is connected to a fifth oil passage 56. The line pressure control valve 54 is connected to a second three-way solenoid valve 60 for line pressure control via a sixth oil passage 58.

Further, a clutch pressure control valve 62 for controlling a clutch pressure is provided in the second oil passage 40 on the second hydraulic chamber 26 side of a portion where the line pressure control valve 54 communicates with the fifth oil passage 56. Is provided using the other end of the branch. This clutch pressure control valve 62 has a third three-way solenoid valve 6 for clutch pressure control via an eighth oil passage 66.
8 is communicated.

The primary pressure control valve 44, the first solenoid valve 52 for primary pressure control, the constant pressure control valve 48,
The line pressure control valve 54, the second three-way solenoid valve 60 for line pressure control, the clutch pressure control valve 62, and the third three-way solenoid valve 68 for clutch pressure control are connected to each other by a ninth oil passage 70.

The clutch pressure control valve 62 communicates with a hydraulic clutch 74 via a tenth oil passage 72 communicating with a seventh oil passage 64. This tenth oil passage 7
A pressure converter 78 is communicated with the pressure transducer 78 via the eleventh oil passage 76 on the way. The pressure transducer 78 can directly detect the oil pressure when controlling the clutch pressure in the hold and start modes, and makes the detected oil pressure coincide with the target clutch pressure. In the drive mode, the clutch pressure becomes substantially equal to the line pressure, which also contributes to the line pressure control.

The hydraulic clutch 74 includes a piston 80,
It comprises an annular spring 82, a first pressure plate 84, a friction plate 86, a second pressure plate 88 and the like.

Further, a control means (ECU) 90 is provided as an electronic control unit for inputting various conditions such as the throttle opening of a carburetor (not shown) of the vehicle and the engine rotation, changing the duty ratio and performing shift control. 90
The first three-way solenoid valve 5 for primary pressure control
2. It is configured to control opening and closing operations of a second three-way solenoid valve 60 for controlling line pressure and a third three-way solenoid valve 68 for controlling clutch pressure, and to supply power to the pressure converter 78. The various signals input to the control means 90 and the function of the input signals will be described in detail. A shift lever position detection signal... P, R, N, D, L, etc. Required line pressure, belt ratio, clutch control, carburetor throttle opening detection signal ... Detects engine torque from memory previously input into the program, determines target belt ratio or target engine speed, carburetor idle position Detection signal of ..... Improvement of accuracy in correction and control of carburetor throttle opening sensor, Accelerator operation signal ........ Detects driver's will by the depression state of accelerator pedal, determines control direction when driving or starting, and brakes Signal: Detects whether the brake pedal is depressed or not, and performs control methods such as disengaging the clutch. Constant,
Power mode option signal: Used as an option to make the performance of the vehicle sporty (or economy).

The control means 90 calculates an engine speed trigger for the throttle opening from an engine speed trigger map, and performs a filter process on the steady state target engine speed when the steady state target engine speed is transiently corrected. In addition, the amount of change in the final target engine speed per unit time is set by a limit value taking into account at least the previous final target engine speed, and the difference between the engine speed trigger and the final target engine speed or the target engine in a steady state is set. The shift control is performed to change the limit value according to the difference between the rotation speed and the final target engine rotation speed.

The control means 90 has a configuration as shown in FIG. 12 and obtains a final target engine speed (NESPRF).

As shown in FIG. 12, the throttle opening (TH
Based on the values of R), the vehicle speed (NCO), and the shift operation, a steady state target engine speed (NESPR) is set (201).

The set target engine speed (NESP)
R) is subjected to transient correction based on the driving operation and the running state of the vehicle (202), and becomes the final target engine speed (NESPRF) subjected to the transient correction.

Then, the actual engine speed (NE)
Target transient engine speed (NES)
(PRF) to adjust the gear ratio so as to perform engine rotation control, that is, gear shift control.

That is, the final target engine speed (N
ESPRF) adjusts the ratio solenoid duty Ur, which becomes the gear ratio, based on the neutral value Un of the ratio solenoid duty Ur after performing the PI control (203) based on the integral value and the belt slip prevention process (204). .

The target engine speed (NESPR)
When setting is made, the engine speed (NES) with respect to the throttle opening (THR) is obtained from a map (RACRVT) (see FIG. 13) using the throttle opening (THR) as a factor.
PRT) and upper limit (NESPRL) and lower limit (NESPRL) of engine speed (NESPRT) with respect to throttle opening (THR) from maps (RACRVH, RACRVL) (FIG. 14) using vehicle speed (NCO) as a factor. ) And the throttle opening (TH
R), the target engine speed (NESPR) is limited by the engine speed (NESPRT), the upper limit (NESPRH), and the lower limit (NESPRL).
Is set.

A map (RACRVT) using the throttle opening (THR) as a factor and a map (RACRVH, RACRVL) using the vehicle speed (NCO) as a factor are provided for each shift position. (T
HR) and vehicle speed (NCO), if the shift position is different, the target engine speed (NESP)
R) are different.

Further, the target engine speed (NESP)
As shown in FIG. 16, the transient correction of R) is performed by subjecting the target engine speed (NESPR) to filter processing (301) to obtain a processed value of NESPF and the final target engine speed (NESPRF) per unit time. Limiting the amount of change, that is, the upper limit (RATUP) of the amount of change in the final target engine speed (NESPRF) per unit time
And a lower limit value (RATLO).

In this rate limit control (302), the final target engine speed (NESPR) per unit time set by the driving operation and the running state of the vehicle is set.
The lower limit value (RATLO) (303) and the upper limit value (RATUP) (304) of the amount of change in F) are, as is apparent from FIG. 16, the last final target engine speed (NESPR).
F), that is, set in consideration of NESPRN.

When the throttle opening (THR) is rapidly increased by a driving operation or when a shift operation is performed, rate limit control (transient control) is performed with a limit value larger than a normal limit value.

The control means 90 calculates an engine speed trigger (NESPRU) for the throttle opening (THR) from an engine speed trigger map (NESPRU map) in addition to the normal control described above.
During transient correction of the steady state target engine speed (NESPR), the steady state target engine speed (NESPR) is corrected.
PR), the amount of change in the final target engine speed per unit time is set by a limit value that takes into account at least the previous final target engine speed, and the engine speed trigger (NESPRU) and the final target are set. Difference from engine speed (NESPRF) (ER
RT) or steady state target engine speed (NE)
SPR) and final target engine speed (NESPRF)
A shift control function is added so as to change the limit value according to the difference (ERRN).

The limit value is a limit value in the increasing direction of the change amount of the final target engine speed (NESPRF) per unit time, that is, an upper limit value (RATUP) and a final target engine speed per unit time (NESPRF). Is a limit value in the decreasing direction of the amount of change, that is, a lower limit value (RATLO).

The upper limit (RATUP) and the lower limit (RA
TLO) is a rate limit control value (RATUPN,
RATLON) and a shift transient control value (RA
TUPS, RATLOS) and the throttle transient control value (RATUPT) are selected and set.

The rate limit control value (RATUP)
N, RATLON) are the steady-state target engine speed (NESPR) and the final target engine speed (NESPR).
PRF) (ERRN) as a factor (RUC)
RVN, RLCRVN).

The shift transient control value (RAT)
UPS, RATLOS) are the steady-state target engine speed (NESPR) and the final target engine speed (N
ESPRF) (ERRN) as a factor (R
UCRVS, RLCRVS).

The throttle transient control value (R
ATUPT) determines an engine speed trigger (NESRU) for the throttle opening (THR) from an engine speed trigger map (RACRVU), and calculates a difference between the engine speed trigger (NESPRU) and the final target engine speed (NESPRF). It is calculated from the relationship (RUCRVT) with (ERRT) as a factor.

In the shift transient control, a lower limit map (RACRVLE, RACRVLE) for calculating a steady-state target engine speed (NESPR) is used.
I, RACRVLP, RACRVLL).

As shown in FIG. 2, an input shaft rotation detecting gear 102 is provided outside the first housing 20, and a first rotation detector on the input shaft side is provided near an outer peripheral portion of the input shaft rotation detecting gear 102. 104 are provided. An output shaft rotation detection gear 106 is provided outside the second housing 22, and a second rotation detector 108 on the output shaft side is provided near an outer peripheral portion of the output shaft rotation detection gear 106. Detection signals from the first rotation detector 104 and the second rotation detector 108 are output to the control means 90 and are used to determine the engine speed and the belt ratio.

The power transmission gear 1 is connected to the hydraulic clutch 74.
A third rotation detector 11 for detecting the rotation of the final output shaft is provided near the outer peripheral portion of the output transmission gear 110.
2 are provided. That is, the third rotation detector 112
Detects the rotation of a reduction gear, a differential, a drive shaft, and a final output shaft directly connected to a tire, and enables detection of a vehicle speed. In addition, the second rotation detector 10
8 and the third rotation detector 112, the hydraulic clutch 74
Can detect the rotation of the input shaft and the output shaft, and can detect the clutch slip amount.

Next, the operation of this embodiment will be described.

In the continuously variable transmission 2, as shown in FIG. 2, an oil pump 30 located on the rotating shaft 18 operates according to the rotation of the rotating shaft 18, and the oil in the oil pan 32 is filtered by an oil filter. Inhaled via. The line pressure, which is the pump pressure, is controlled by the line pressure control valve 54. If the amount of leakage from the line pressure control valve 54, that is, the relief amount of the line pressure control valve 54, is large, the line pressure becomes low, and conversely, the line pressure becomes small. If the line pressure is high.

The operation of the line pressure control valve 54 is controlled by a dedicated second three-way solenoid valve 60, and the line pressure control valve 54 operates following the operation of the second three-way solenoid valve 60. The second three-way solenoid valve 60 is controlled at a constant frequency duty ratio. That is, the duty ratio of 0% is a state in which the second three-way solenoid valve 60 does not operate at all, the output side is connected to the atmosphere side, and the output oil pressure becomes zero. Also, the duty ratio 10
When it is 0%, the second three-way solenoid valve 60 operates, the output side is connected to the input side, and the maximum output oil pressure is the same as the control pressure. That is, the output oil pressure is changed by changing the duty ratio to the second three-way solenoid valve 60. Therefore, the characteristics of the second three-way solenoid valve 60 allow the line pressure control valve 54 to operate in an analog manner,
The line pressure can be controlled by arbitrarily changing the duty ratio of 0. The operation of the second three-way solenoid valve 60 is controlled by the control means 90.

The primary pressure for shifting control is controlled by a primary pressure control valve 44, and the operation of this primary pressure control valve 44 is also controlled by a dedicated first three-way solenoid valve 52, similarly to the line pressure control valve 54. I have. This first
The three-way solenoid valve 52 is used to conduct the primary pressure to the line pressure or to conduct the primary pressure to the atmosphere side, and to conduct the line pressure to shift the belt ratio to the overdriver side or to conduct the belt ratio to the atmosphere side. To the full low side.

Clutch pressure control valve 6 for controlling clutch pressure
Reference numeral 2 denotes a connection to the line pressure side when the maximum clutch pressure is required, and a connection to the atmosphere side when the minimum clutch pressure is required. This clutch pressure control valve 62 is also similar to the line pressure control valve 54 and the primary pressure control valve 44,
Since the operation is controlled by the dedicated third three-way solenoid valve 68, the description is omitted here. The clutch pressure varies within a range from a minimum atmospheric pressure (zero) to a maximum line pressure.

There are, for example, five patterns for controlling the clutch pressure. (1) Neutral mode: When the shift position is N or P and the hydraulic clutch is completely disengaged, the clutch pressure is the minimum pressure (zero). (2) Hold mode: When the shift position is D or R, release the throttle. If there is no intention to drive, or if you want to decelerate during running and want to cut off the engine torque, the clutch pressure is low enough to make the clutch contact (3), normal start mode .... When trying to do so, the clutch pressure is adjusted to an appropriate level according to the engine generated torque (clutch input torque) that prevents the engine from blowing up and allows the vehicle to operate smoothly (4), special start mode ... (a), vehicle speed When the shift lever is repeatedly used in the order of D → N → D at 8 ° / H or more, or (B) a state in which the braking state is released at 8〓 / H <vehicle speed <15〓 / H during deceleration operation; (5) a drive mode: when the vehicle shifts to a complete running state and the clutch is completely engaged, There are five high clutch pressure levels that can afford enough to withstand engine torque.

This pattern (1) is performed by a dedicated switching valve (not shown) that is interlocked with the shift operation, and the other (2), (3), (4), and (5) are the first, This is performed by controlling the duty ratio of the second and third three-way solenoid valves 52, 60 and 68. In particular, in the state (5), the seventh oil passage 64 and the tenth oil passage 72 are communicated by the clutch pressure control valve 62 so that a maximum pressure is generated, and the clutch pressure becomes the same as the line pressure.

The primary pressure control valve 44, the line pressure control valve 54, and the clutch pressure control valve 62 are respectively controlled by output hydraulic pressures from first, second, and third three-way solenoid valves 52, 60, and 68. However, the control oil pressure for controlling the first, second and third three-way solenoid valves 52, 60 and 68 is a constant oil pressure adjusted by the constant pressure control valve 48. This control oil pressure is always lower than the line pressure, but is a stable and constant pressure. The control oil pressure is also introduced into each of the control valves 44, 54, 62 to stabilize the control valves 44, 54, 62.

Next, the electronic control of the continuously variable transmission 2 will be described.

The continuously variable transmission 2 is hydraulically controlled, and receives a command from the control means 90 to control an appropriate line pressure for belt holding and torque transmission and a primary pressure for changing a gear ratio (belt ratio). The pressure and the clutch pressure for securely connecting the hydraulic clutch 74 are each secured.

Referring to FIG. 1, when the final target engine speed (NESPRF) reaches the engine speed trigger (NESPRU), the throttle transient control ends (point C). At this time, the engine rotation speed trigger (NESPRU) and the final target engine rotation speed (NESPRF) become substantially the same, and the routine shifts to general rate limit control.

Since the engine speed (NE) is controlled so as to be equal to the final target engine speed (NESPRF), the throttle transient control is performed by setting the engine speed (NE) to the engine speed trigger (NESPRU). The process is performed until the user approaches the vicinity.

Therefore, as in the prior art disclosed in FIG.
This prevents excessive throttle transient control. Also, as shown at point D in FIG. 1, even when the engine speed (NE) temporarily drops,
The temporary increase of the final target engine speed (NESPRF) is prevented without affecting the final target engine speed (NESPRF) or the general upper limit (RATOPN).

Next, a description will be given along a flowchart for setting the target engine speed in the steady state in FIG.

When the setting program starts (401), the engine speed (NESPRT) for the throttle opening (THR) is obtained, and the engine speed (NESPRT) for the throttle opening (THR) is obtained.
Upper limit (NESPRH) and lower limit (NESPRL)
(402) (see FIG. 9), and the throttle opening (TH
R) and the engine speed (NESPRT) with respect to the throttle opening (THR).
SPRT) and the upper limit value (NESPRH).
03).

In this comparison judgment (403), NES
If PRT <NESPRH, the throttle opening (T
HR) and engine speed (NSPRT) with respect to throttle opening (THR).
The process proceeds to a comparison judgment (404) with the lower limit value (ESPRL) of the ESPRT). If NESPRT ≧ NESPRH, the upper limit value (NESPRH) of the engine speed (NESPRT) with respect to the throttle (THR) is set to the target engine in the steady state. Rotational speed (NESPR) (40
5), and proceed to the end (408).

In the above-mentioned comparison judgment (404), when NESPRT> NESPRL, the engine speed (NESP) with respect to the throttle opening (THR) is determined.
RT) to the steady state target engine speed (NESP)
R) (406), and the process proceeds to the end (408).
If SPRT ≦ NESPRL, the engine speed (NESPRT) with respect to the throttle opening (THR)
The lower limit value (NESPRL) is set as the steady state target engine speed (NESPR) (407), and the process ends (408).
Move to

A description will now be given with reference to the flowchart of FIG. 11 for correcting the transient of the target engine speed.

The target engine speed (NES) in the steady state
When the transient correction program (PR) is started (501), the target engine speed (NESPR) in a steady state is filtered and set to NESPF (502).

Then, an upper limit (RATUP), which is a limit value in the increasing direction, and a lower limit value (RATLO), which is a limit value in the decreasing direction, of the amount of change in the final target engine speed (NESPRF) per unit time are set. 503).

As shown in FIG. 3, when the flowchart for setting the upper limit (RATUP) is started (601), the setting process (503) starts from the equation | NESPR-NESPRF |, that is, the target engine speed (NES) in the steady state.
PR), the final target engine speed (NESPRF), and the difference (absolute value) (ERRN) are obtained (602), and the general upper limit is obtained from a RATUPN map which is a general upper limit (RATUP), ie, RUCRVN (ERRN) in FIG. (RA
TUPN) is obtained (603).

Next, it is determined whether or not the traveling mode is LOW (604). If this determination (604) is NO, the determination is made as to whether or not the traveling mode is POWER (605). If the judgment (604) is YES, RACRVUL which is the RACRVU at the time of LOW is shifted.
(THR) is set as an engine speed trigger (NESPRU) at the time of throttle transient control (606).

If the determination (605) of whether or not the traveling mode is POWER is NO, the ECONOMY
RACRVUE (THR), which is the RACRVU at the time, is set as the engine speed trigger (NESPRU) at the time of throttle transient control (607). If the determination (605) is YES, RACRVUP (THR), the RACRVU at the time of POWER, is throttled. An engine speed trigger (NESPRU) at the time of transient control is set (608).

Then, the final target engine speed (NESPRF) subjected to the transient correction is compared with the engine speed trigger (NESPRU) for the throttle transient control (609), and NESPRF <NESPRU.
In the case of, the difference (ERRT) is calculated by the expression NESPRU-NESPRF (610), and RATUPT
From the map RUCRVT (ERRT) to the upper limit value (RATUP) R at the time of throttle transient control
ATUPT is obtained (611), and the process proceeds to shift transient control setting (612).

Further, in the comparison judgment (609), NE
If SPRF ≧ NESPRU, 0 (zero) is set to RA
TUPT is set (613), and the process proceeds to the setting of shift transient control (612).

Next, a RATUPS flag (RATUP) which is the upper limit (RATUP) at the time of shift transient control is set.
FLGU) is set (SET) or cleared (CLE)
AR) is determined (614), and in the determination (614), the RATUPS flag (RATF
LGU) is set (SET), RA
A value obtained by subtracting 1 from the TUPS timer (TIMESU) is used as the RATUPS timer (TIMESU) (61).
5) In the judgment (614), if the RATUPS flag (RATFLGU) is cleared (CLEAR), 0 (zero) is set as RATUPS, and
0 (zero) is used as a RATUPS timer (TIMESU), and a RATUPS flag (RATFFLGU) is cleared (CLEAR) (616).

A value obtained by subtracting 1 from the timer for RATUPS (TIMESU) is used as a value for the timer for RATUPS (TIMES).
After the processing (615) for U), a comparison determination is made between the RATUPS timer (TIMESU) and 0 (zero) (61).
7) If TIMESU> 0, RUCRVS
(ERRN) is set to RATUPS (618), and TIME
If SU ≦ 0, the process proceeds to the above-described processing (616).

Further, RUCRVS (ERRN) is changed to RAT
After the process for setting the UPS (618), a comparison is made between the target engine speed (NESPR) in the normal state and the final target engine speed (NESPRF) + RATUPS (6).
19) When NESPR> NESPRF + RATUPS, MAX (RATUPN, RATUPS, RATUPS)
TUPT) is selected as the RATUP (620), and the setting program is terminated (621).

Further, NESPR ≦ NESPRF + RAT
In the case of the UPS, the processing shifts to the above-described processing (616). When this processing (616) ends, MAX (RAT
After the process of setting the largest one among UPN, RATUPS, RATUPT) to RATUP (620), the process proceeds to the end of the setting program (621).

Further, as shown in FIG.
When the TLO (TLO) setting flowchart starts (701), the final target engine speed (NESPRF) and RA
A comparison is made (702) with the TLO engine speed trigger (NETRL), and if NESPRF> NETRL, the expression | NESPR-NESPRF |
PR), the final target engine speed (NESPRF) and the difference (absolute value) (ERRN) are obtained (703), and the NESP
MI that is the minimum RATLO when RF ≦ NETRL
The NRL is set to RATLO (704), and the process proceeds to the end of the setting program (714).

Then, after the process of calculating the difference (absolute value) (ERRN) (703), the RL of the RATLON map
CRVN (ERRN) is a general RATLO RAT
LON is set (705), and the process proceeds to the setting of shift transient control (706).

Next, a flag for RATLOS (RATFL)
GL) is set (SET) or cleared (CLEA)
R) is determined (707), and in the determination (707), the flag for RATLOS (RATF
LGL) is set (SET), RA
A value obtained by subtracting 1 from the TLOS timer (TIMESL) is used as the RATLOS timer (TIMESL) (70
8) In the judgment (707), when the RATLOS flag (RATFGL) is cleared (CLEAR), 0 (zero) is set to RATLOS which is RATLO at the time of shift transient control, and 0 (zero) is set. A timer for RATLOS (TIMESL) is set, and a flag for RATLOS (RATFLGL) is cleared (CLEAR) (709).

The value obtained by subtracting 1 from the RATLOS timer (TIMESL) is used as the value of the RATLOS timer (TIMES).
L), the processing (708) is performed, and a comparison is made between the RATLOS timer (TIMESL) and 0 (zero) (71).
0), and if TIMESL> 0, RUCRVS
(ERRN) is set to RATLOS (711), and TIME
If SL ≦ 0, the flow shifts to the above-described processing (709).

Further, RUCRVS (ERRN) is changed to RAT
After the process of setting LOS (711), the target engine speed (NESPR) in the normal state and the final target engine speed (NESPRF) -RATLOS are compared and determined (7).
12) If NESPR <NESPRF-RATLOS, the largest one from MAX (RATLON, RATLOS) is selected as RATLO (713),
The setting program ends (714).

Further, NESPR ≧ NESPRF-RAT
In the case of the LOS, the process proceeds to the above-described processing (709). When this processing (709) ends, MAX (RAT
LON, RATLOS)
After the process for setting LO (713), the process proceeds to the end of the setting program (714).

Then, the upper limit value (RATU) of the amount of change of the final target engine speed (NESPRF) per unit time is calculated.
P) and the lower limit (RATLO) (503), the steady state target engine speed (NESPF) after the filter processing and the last final target engine speed (N
ESPRN) is compared (504).

Then, in the comparison judgment (504), NE is set.
If SPR <NESPRN, a value obtained by subtracting the steady-state target engine speed (NESPF) after filtering from the last final target engine speed (NESPRN) is calculated as the final target engine speed (NESRP) per unit time.
The process proceeds to a comparison judgment (505) with the lower limit (RATLO) of the variation of PRF).

In the comparison judgment (504), the NES
When PR ≧ NESPRN, a value obtained by subtracting the previous final target engine speed (NESPRN) from the target engine speed (NESPF) in the steady state after the filter processing and the final target engine speed (NESP) per unit time are used.
Then, the process proceeds to the comparison judgment (506) with the upper limit value (RATUP) of the change amount of RF).

In the above-mentioned comparison judgment (505), NE
If SPRN-NESPF> RATLO, NES
The value of PRN-RATLO is set to the final target engine speed (NESPRF) (507), and the NESP
If RN-NESPF ≦ RATLO, steady-state target engine speed (NESPF) after filtering
Is the final target engine speed (NESPRF) (508).

In the above-mentioned comparison judgment (506), if NESPF-NESPRN ≦ RATUP, the steady-state target engine speed (NESPF) after the filter processing is changed to the final target engine speed (NESP).
RF) (508), and the NESPF-
If NESPRN> RATUP, a value obtained by adding the upper limit value (RATUP) of the variation of the final target engine speed (NESPRF) per unit time to the last final target engine speed (NESPRN) is used as the final target engine speed. (NESPRF) (509).

Then, each processing (507), (508),
(509) Final target engine speed (NESPR
F) to the last target engine speed (NESPR)
N) (510), and end (511).

Here, a flowchart for setting the shift transient control will be described with reference to FIG.

When the flow chart for setting the shift transient control starts (801), the processing shifts to a setting map as shown in FIG. 12 (802).

Then, in the setting map as shown in FIG. 10, it is determined whether or not the setting is the previous value Z- ¹ which is the previous target engine rotation speed (803), and this determination (803) is NO. In the case of (1), it is determined whether or not the setting is LO in the setting map as shown in FIG.
Perform 4).

If the judgment (803) is YES, the flow chart for setting the shift transient control is terminated (807).

If the above judgment (804) is NO,
Set the RATUPS flag (RATFLGU) (S
ET), and set TIMESU to TIMESU (80
5) The shift transient control setting flowchart is terminated (807), and if the judgment (804) is YES, the RATLOS flag (RATFFLGL) is set (SET), TIMESLLI is set to TIMESL (806), and shift is performed. This is the end of the transient control setting flowchart (807).

The symbols used in FIG. 9 will be described below. D: Shift position is drive L: Shift position is low ECONOMY: Travel mode is economy POWER: Travel mode is power LOW: Travel mode is low RACORVH at ECONOMY RACRVHP: RACRVH at POWER POWER RACRVHL: RACRVH at LOW RACRVLE: RACRVL at ECONOMY RACRVLEI: RACR at idle switch ON
VLE RACRVLP: RACRVL at POWER time RACRVLL: RACRVL at LOW time

As a result, as shown at point D in FIG. 1, it is possible to prevent the fluctuation of the actual engine speed and the influence of the difference between the actual engine speed and the target engine speed on the final target engine speed. Transient correction of the target engine rotational speed in the steady state can be prevented from being performed more than necessary, and reliability of the shift control can be improved, which is practically advantageous.

Further, by controlling the shift so as to change the limit value in accordance with the difference between the engine speed trigger and the final target engine speed or the difference between the steady state target engine speed and the final target engine speed, It is possible to set a limit value suitable for the driving operation and the running state of the vehicle, improve the drivability, and easily reflect the change state of the engine generated torque on the change of the vehicle speed,
It is practically advantageous.

Further, since it can be dealt with only by changing the control program of the control means 90, the memory capacity can be saved and the tuning operation can be facilitated, which is economically and practically advantageous.

[0093]

As described above in detail, according to the present invention, the groove width between the fixed pulley part and the movable pulley part which is detachably attached to the fixed pulley part is reduced by the hydraulic pressure. The final target engine speed after transient correction is applied to the steady-state target engine speed calculated from the throttle opening map and the vehicle speed map by increasing or decreasing the radius of rotation of the belt wound around both pulleys In the shift control method for a continuously variable transmission, the shift control is performed to match the actual engine rotation speed with the actual engine rotation speed. At the time of correction, filter processing is performed on the steady-state target engine speed, and the amount of change in the final target engine speed per unit time is reduced. Set at least with the limit value that takes into account the previous final target engine speed, and according to the difference between the engine speed trigger and the final target engine speed or the difference between the steady-state target engine speed and the final target engine speed. The shift control is performed to change the limit value by changing the actual engine speed and the difference between the actual engine speed and the target engine speed can be prevented from affecting the final target engine speed. Transient correction of the target engine rotational speed can be prevented from being performed more than necessary, and reliability of the shift control can be improved. Also,
By controlling the shift so as to change the limit value according to the difference between the engine speed trigger and the final target engine speed or the difference between the steady-state target engine speed and the final target engine speed, the driving operation and the vehicle It is possible to set a limit value suitable for the running state, improve the drivability, and easily reflect the change state of the engine generated torque on the change of the vehicle speed, which is practically advantageous.
Furthermore, by being able to deal with only program changes,
This can save the memory capacity and facilitate the tuning operation, which is economically and practically advantageous.

[Brief description of the drawings]

FIG. 1A is a time chart of a throttle opening (THR) showing an embodiment of the present invention. (B) Actual engine speed (NE), steady state target engine speed (NESPR), final target engine speed (NESPRF), and engine speed trigger (N)
7 is a time chart of (ESPRU). (C) The difference (ERR) between the engine speed trigger (NESPRU) and the final target engine speed (NESPRF)
T) and steady state target engine speed (NESPR)
FIG. 9 is a time chart of a difference (ERRN) between the target engine rotation speed (NESPRF) and a final target engine rotation speed (NESPRF). (D) The limit value (R) in the increasing direction of the final target engine speed change amount per time during the throttle transient control.
7 is a time chart of (ATUPT) and a general limit value (RATUPN) in the increasing direction of the final target engine speed change amount per time.

FIG. 2 is a schematic diagram of a continuously variable transmission and a hydraulic circuit.

FIG. 3 is a flowchart for setting a limit value (RATUP) in an increasing direction of a change amount of a final target engine rotation speed per time.

FIG. 4 is a flowchart for setting a limit value (RATLO) in a decreasing direction of a final target engine rotation speed change amount per time.

FIG. 5 is a flowchart for setting shift transient control.

FIG. 6 is a RATUP map.

FIG. 7 is a RATLO map.

FIG. 8 is a NESPRU map.

FIG. 9 shows a target engine speed (NESPRT), a target engine speed upper limit (NESPRH), and a target engine speed lower limit (N) based on the throttle opening (THR).
7 is a map for setting (ESPRL).

FIG. 10 is a setting map for shift transient control.

FIG. 11 is a flowchart for transient correction of a target engine rotation speed (NESPR).

FIG. 12 is a block diagram of a shift control loop.

FIG. 13 is a diagram showing a target engine speed (NESPRT).

FIG. 14 shows upper and lower limit values (NES) of a target engine speed.
PRH, NESPRL).

FIG. 15 shows a target engine speed (NESP) in a steady state.
It is a flowchart for setting of R).

FIG. 16 shows a target engine rotation speed (NESP) in a steady state.
It is a block diagram of transient correction of R).

FIG. 17 shows a target engine speed (NESP) in a steady state.
It is a time chart of R).

FIG. 18A is a time chart of a throttle opening (THR) showing a conventional technique of the present invention. (B) Actual engine speed (NE), steady state target engine speed (NESPR), final target engine speed (NESPRF), and engine speed trigger (N)
7 is a time chart of (ESPRU). (C) The difference (ERRT) between the engine speed trigger (NESPRU) and the actual engine speed (NE) and the difference (ERRN) between the steady-state target engine speed (NESPR) and the actual engine speed (NE). 4) is a time chart. (D) The limit value (R) in the increasing direction of the final target engine speed change amount per time during the throttle transient control.
7 is a time chart of (ATUPT) and a general limit value (RATUPN) in the increasing direction of the final target engine speed change amount per time.

[Explanation of symbols]

 2 Continuously Variable Transmission 4 Belt 6 Drive Pulley 12 Driven Pulley 18 Rotary Shaft 30 Oil Pump 38 First Oil Passage 40 Second Oil Passage 42 Pressure Control Valve Means 44 Primary Pressure Control Valve 46 Third Oil Passage 48 Constant Pressure Control Valve 50 Fourth oil passage 52 First three-way solenoid valve for primary pressure control 54 Line pressure control valve 56 Fifth oil passage 58 Sixth oil passage 60 Second three-way solenoid valve for line pressure control 62 Clutch pressure control valve 64 7 oil passage 66 eighth oil passage 68 third three-way solenoid valve for controlling clutch pressure 70 ninth oil passage 72 10th oil passage 74 hydraulic clutch 76 11th oil passage 78 pressure converter 90 control means

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F16H 9/00 F16H 59/00-63/48

Claims (1)

(57) [Claims] 1. A groove between a fixed pulley portion and a movable pulley portion attached to and detachable from the fixed pulley portion, between the two pulley portions is increased or decreased by hydraulic pressure to be wound around the two pulley portions. In order to make the actual engine speed match the final target engine speed after transiently modifying the steady-state target engine speed calculated from the throttle opening map and the vehicle speed map by increasing and decreasing the belt turning radius. In the shift control method for a continuously variable transmission that performs shift control, an engine rotation speed trigger for a throttle opening is calculated from an engine rotation speed trigger map, and the steady state target engine rotation speed is corrected when the steady state target engine rotation speed is transiently corrected To the final target engine speed per unit time. The limit value is set by a limit value in consideration of the rotation speed, and the limit value is changed according to the difference between the engine speed trigger and the final target engine speed or the difference between the steady-state target engine speed and the final target engine speed. A shift control method for a continuously variable transmission, wherein the shift control is performed to perform the shift control.