JP3206768B2 - Shift 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 shift control device for a continuously variable transmission, and more particularly to suppressing a rise in engine speed after shifting from a start mode in a control mode to a drive mode to improve a starting feeling. The present invention also relates to a shift control device for a continuously variable transmission that can prevent occurrence of overshoot and swell of the engine speed.

[0002]

2. Description of the Related Art In a vehicle, a transmission is interposed between an internal combustion engine and wheels since the characteristics of the internal combustion engine are unsuitable as they are. This transmission changes the driving force and the number of revolutions of the wheels in accordance with the running conditions of the vehicle which vary over a wide range, thereby sufficiently exhibiting the performance of the internal combustion engine.

[0003] As a transmission, there is a continuously variable transmission having a hydraulic clutch and continuously changing a speed ratio (belt ratio) by changing a rotation radius of a belt wound around a driving pulley and a driven pulley. .

A continuously variable transmission mounted on a vehicle is provided with a transmission control device for controlling an engine speed, a gear ratio, and the like according to various control modes (control modes) determined by a control means (ECM). ing.

In this transmission control apparatus, a line pressure control valve, a clutch pressure control valve, and a ratio pressure control valve are provided as various pressure control valves in order to control the hydraulic pressure applied to the driving pulley, the driven pulley, and the hydraulic clutch. In addition, a line solenoid valve, a clutch solenoid valve, and a ratio solenoid valve for operating these pressure control valves are provided.

The various control modes include, for example, a neutral mode, a hold mode, a normal start mode as a start mode, and a drive mode.

The neutral mode is determined when the position of the shift lever is parking "P" or neutral "N" and the hydraulic clutch is completely disengaged, and the clutch pressure to the hydraulic clutch is zero.

[0008] The hold mode is determined based on the position of the shift lever, the engine speed, the vehicle speed, and the depressed state of the accelerator pedal. That is, in the hold mode, the condition that the position of the shift lever is drive “D”, low “L” or reverse “R”, and the engine speed (NE) <1000 rpm
And the condition of the rotation of the clutch output shaft of the hydraulic clutch (vehicle speed) (NCO) <8 km / h, and the driver demand switch is turned off, that is, the driver intends to run the vehicle without the accelerator pedal being depressed. It is determined when the condition without the above is satisfied. In this hold mode, the clutch pressure of the hydraulic clutch is set such that the clutch pressure target value becomes 4.5 kg / cm ² (creep pressure).
Feedback control is performed by a clutch solenoid duty output signal to the clutch solenoid valve. The clutch solenoid duty output signal is a pulse signal output from the control signal, and controls the operation of the clutch solenoid valve by changing the duty ratio. That is, this hold mode is used when there is no driving intention of the vehicle, or
This is the case when it is desired to decelerate during running to cut off the engine torque. Also, the clutch pressure of the hydraulic clutch is
It hardly transmits engine torque, but is maintained at a low value such that the hydraulic clutch is slightly engaged.

The normal start mode is determined based on the position of the shift lever, the engine speed, the vehicle speed, and the depressed state of the accelerator pedal. That is, in this normal start mode, the position of the shift lever is set to drive “D” and low “L”.
Or, the condition of reverse "R" and vehicle speed (NCO) <8k
m / h, the condition where the accelerator pedal is depressed and the driver demand switch is on, and the engine speed (NE)
It is determined when the condition of ≧ 1000 rpm is satisfied. In the normal start mode, when the hydraulic clutch is to be engaged again when the vehicle starts or after the clutch is disengaged, a clutch pressure corresponding to the engine generated torque (clutch input torque) is applied to the hydraulic clutch, whereby The clutch pressure is maintained at an appropriate value with a quick response in order to prevent the engine speed from rising and to start the vehicle smoothly.

The drive mode is determined based on the position of the shift lever, the vehicle speed, and the clutch slip amount. That is, in this drive mode, the shift lever position satisfies the condition of drive "D", low "L" or reverse "R", the condition of vehicle speed (NCO) ≥ 8 km / h, and the clutch slip amount ≤ 20 rpm. It is determined when it is done. In this drive mode, the vehicle shifts to a complete running state and the hydraulic clutch is completely connected (clutch lockup state), or the hydraulic clutch substantially locks up when shifting from the normal start mode. When the hydraulic clutch is completely connected to the running state and the hydraulic clutch is completely engaged, a high clutch pressure (pressure equal to the line pressure) having a margin enough to withstand the engine torque is applied to the hydraulic clutch.

A shift control device for such a continuously variable transmission is disclosed, for example, in Japanese Patent Application Laid-Open No. 64-44346. In this publication, a throttle opening detection signal and a vehicle speed detection signal are input to a control unit, and a first target engine rotation speed based on a throttle opening detection signal and a second target engine rotation speed based on a vehicle speed detection signal are shifted. The optimum target engine speed is determined based on the rotation speed limit command at the position, and the shift control is performed in accordance with the optimum target engine speed.

[0012]

By the way, in a continuously variable transmission, during a normal start mode in various control modes, a solenoid duty value to a ratio solenoid valve is 0%, and hydraulic pressure is applied to a drive pulley. It is not working. As described above, when the mode is shifted from the state in which the hydraulic pressure is not acting on the drive pulley to the drive mode,
The shift control is delayed, and it takes a long time until the engine speed converges to the target engine speed. Therefore, there is a disadvantage that the shift to the drive mode adversely affects the line pressure and the like and deteriorates the starting feeling.

That is, as shown in FIGS. 9 and 10, the normal start mode (NST) is changed to the drive mode (DR).
The determination to V) is made when the rotation difference between the clutch input shaft and the clutch output shaft of the hydraulic clutch becomes small, that is, when the clutch input shaft and the clutch output shaft rotate substantially synchronously.

In the normal start mode (NST), since the hydraulic clutch is slipping, the clutch input speed (NOI) ≠ the clutch output speed (vehicle speed) (NCO), and the engine speed (NE) ) ≠ speed ratio (RATC) x clutch output speed (NCO) (1)
It becomes an expression.

On the other hand, in the drive mode (DRV), the clutch input speed (NCI) = the clutch output speed (NCO), and the engine speed (NE) = the speed ratio (RATC) × the clutch output speed. Number (NCO) ... (2)
It becomes an expression.

According to the above equations (1) and (2), in the drive mode (DRV), the engine speed (NE) is determined by the clutch output speed (NCO) and the gear ratio (RATC). However, the normal start mode (NS
At T), the engine speed (NE) has not been determined.

In the normal start mode (NST),
The above equation (2) is satisfied, only if the normal start mode (NST) of the drive mode (DRV) migrated point _{X 10.}

In FIG. 11, the transmission ratio (RAT)
C) is fixed at full low (F / L) and the start control is performed. In this case, the engine speed (NE)
Is maintained at a constant speed by the clutch pressure control during the normal start mode (NST). During the normal start mode (NST), the gear ratio (RAT)
Since C) is fixed at full low (F / L), the clutch input speed (NCI) is also a constant speed. Then, when the clutch input shaft and the clutch output shaft rotate in synchronization with each other and shift from the normal start mode (NST) to the drive mode (DRV), the engine speed (NE)
Is determined by the above equation (2).

Since the shift control in the drive mode (DRV) is feedback-controlled, an error is generated between the filtered target engine speed (NESPRF), which is the target engine speed, and the actual engine speed (NE). Unless
Since the speed change ratio (RATC) does not change and the speed change control is in a slow state, the delay of the speed change control is increased, and the inertia of the vehicle body is larger than the inertia of the internal combustion engine.

For this reason, the normal start mode (NS
T), the engine speed (NE) is changed to the clutch output speed (NC) for a while after shifting to the drive mode (DRV).
O) and the gear ratio (RATC) at the time of transition from the normal start mode (NST) to the drive mode (DRV). Therefore, the difference between the full low line (F / L LINE), which is the speed ratio limit value, and the target engine speed (NESPRF) after filtering increases, and the engine speed (NE) rises (FIGS. 9 and 10). , 1
1 (indicated by the hatched portion).

As described above, when the engine speed (NE) rises, the starting feeling deteriorates, and when the shift control is performed so that the engine speed (NE) absorbs the rise, the engine speed becomes higher. (NE) overshoot and swell occurred.

At this time, if the filtered target engine speed (NESPRF) matches the full low line (F / R LINE) after shifting to the drive mode (DRV), the engine speed (NE) is blown. No rise.
However, the actual target engine speed after filtering (NESP
RF) is the lower limit line (RATC) than the full low line.
LINE), the lower the throttle opening (THR), the lower the limit line (RATCLINE).

[0023]

SUMMARY OF THE INVENTION Accordingly, in order to eliminate the above-mentioned disadvantages, the present invention changes the rotation ratio of the belt wound around the driving pulley and the driven pulley in various control modes to continuously change the gear ratio. In the shift control device for a continuously variable transmission for a vehicle, the clutch output rotational speed is triggered when the vehicle starts in the various control modes or in a start mode in which the clutch is re-engaged after the clutch is disengaged. When the value is equal to or greater than the value, the belt is changed so as to reduce the gear ratio by changing the turning radius of the belt,
The speed ratio limit value immediately after the shift to the drive mode is set to the target engine speed so as to suppress the engine speed assumed based on the value of the speed ratio when the shift to the drive mode in which the clutch is completely engaged from the start mode. A control means for approaching the side is provided.

[0024]

According to the structure of the present invention, when the clutch output rotation speed is equal to or more than the trigger value in the start mode in which the vehicle is started in various control modes or the clutch is re-engaged after the clutch is disengaged. By changing the turning radius to reduce the gear ratio, the engine speed assumed to be suppressed by the value of the gear ratio when shifting from this start mode to the drive mode in which the clutch is completely engaged is suppressed. Since the speed ratio limit value immediately after the transition to the drive mode is closer to the target engine speed side, after shifting from the start mode to the drive mode, the speed ratio limit value and the target engine speed are reduced to reduce the engine speed. Suppresses the upswing, thus improving the starting feeling by smoothing the starting of the vehicle, and the overshoot of the engine speed. The occurrence of the can be prevented.

[0025]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention; 1 to 8 show an embodiment of the present invention. In FIG. 8, reference numeral 2 denotes a continuously variable transmission mounted on the vehicle and transmitting the driving force of an internal combustion engine (not shown) to the wheel side. The continuously variable transmission 2 includes a driving pulley (primary pulley) 4, a driven pulley (secondary pulley) 6, and a belt 8 wound around the driving pulley 4 and the driven pulley 6, and is hydraulically controlled. The rotation radius of the lever 8 is changed to continuously change the gear ratio.

The drive pulley 4 includes a drive shaft 10 connected to the internal combustion engine, a drive-side fixed pulley piece 12 provided integrally with the drive shaft 10, And a drive-side movable pulley piece 14 provided non-rotatably. A drive-side belt groove 16 around which the belt 8 is wound is formed between the drive-side fixed pulley piece 12 and the drive-side movable pulley piece 14. On the back side of the drive-side movable pulley portion 14, a drive-side housing 20 that forms a drive-side hydraulic chamber 18 in cooperation with the back surface of the drive-side movable pulley portion 14 is fixed to the drive shaft 10. I have. A drive shaft side oil passage 22 formed at an end portion of the drive shaft 10 is communicated with the drive side hydraulic chamber 18.

An oil pump 24 is provided on the rear side of the driving-side fixed pulley piece 12. The oil pump 24 is supported by a pump housing 26 fixed to the drive shaft 10. This oil pump 2
The oil suction passage 30 is driven by the rotation of the drive shaft 10 and connects the oil in the oil pan 28 to the suction side.
And lubricated from the discharge side to a hydraulic control system or a lubrication system. In the oil pan 28, the oil suction passage 3
An oil strainer 32 is attached to the opening of the oil suction passage 30 for filtering the oil to zero.

The driven pulley 6 is provided with a driven shaft 34 arranged in parallel with the drive shaft 10 and a driven shaft provided corresponding to the drive side movable pulley piece 14 and provided integrally with the driven shaft 34. A side fixed pulley portion 36 and a driven side movable pulley portion 38 arranged corresponding to the drive side fixed pulley portion 12 and provided on the driven shaft 34 so as to be axially movable and non-rotatably provided. are doing. Driven side fixed pulley piece 36
A driven-side belt groove 40 around which the belt 8 is wound is formed between the driven-side movable pulley piece 38 and the driven-side movable pulley piece 38. On the back side of the driven side movable pulley portion 38, a driven side housing 44 forming a driven side hydraulic chamber 42 in cooperation with the back side of the driven side movable pulley portion 38 is fixed to the driven shaft 34. I have. The driven-side hydraulic chamber 42 is in communication with a driven-shaft-side oil passage 46 formed at an end portion of the driven shaft 34.

In the driven hydraulic chamber 42, between the back surface of the driven movable pulley 38 and the driven housing 44, the driven movable pulley 38 is pressed toward the driven fixed pulley 36. The spring 48 is contracted.
The spring 48 keeps the gear ratio full low (F / L) and prevents the belt 8 from slipping even when the rotation of the oil pump 24 is low and the line pressure (pump pressure) is low at the time of starting the internal combustion engine or the like. The minimum belt holding force is given.

A hydraulic clutch 50 is provided on the rear side of the driven-side fixed pulley piece 36.

The hydraulic clutch 50 includes a clutch casing 52 fixed at the end of a driven shaft 34 serving as a clutch input shaft, and a step 54 of the clutch casing 52.
A pressing piston 56 slidably provided in the driven shaft 34 so as to be axially movable, a clutch hydraulic chamber 58 formed between the clutch casing 52 and the pressing piston 56, and the clutch hydraulic chamber 58 is reduced. A diaphragm spring 60 for urging the pressing piston 56 in the direction, and a direction substantially parallel to the axial direction of the driven shaft 34 so as to move in the axial direction of the driven shaft 34 by the pushing force of the pressing piston 56 and the urging force of the diaphragm spring 60. Clutch casing 5 located
2, a pressure plate 64 slidably provided on the outer peripheral edge 62 of the clutch casing 52, an end plate 66 connected to an end of the outer peripheral edge 62 of the clutch casing 52, and a pressure plate 6.
And a friction plate 70 disposed in a clutch space 68 between the end plate 4 and the end plate 66. A driven shaft clutch oil passage 72 formed at an end of the driven shaft 34 communicates with the clutch hydraulic chamber 58.

The friction plate 70 is connected to a clutch output shaft 74 rotatably provided on the driven shaft 34.

In the hydraulic clutch 50, when the hydraulic pressure acting on the clutch hydraulic chamber 58 is increased, the pressing piston 56 is pushed, and the pressure plate 64 is pushed by the urging force of the diaphragm spring 60. The pressure plate 64 makes the friction plate 70 adhere to the end plate 66,
The connected state of the hydraulic clutch 50, that is, the connected state.
On the other hand, when the clutch pressure applied to the clutch hydraulic chamber 58 is reduced, the urging force of the diaphragm spring 60 causes the pressing piston 56 to move in the contracting direction of the clutch hydraulic chamber 58, and the friction plate 70 to be separated from the end plate 66. The hydraulic clutch 50 is disengaged. Therefore, this hydraulic clutch 50
The clutch is engaged / disengaged depending on the clutch pressure state, and interrupts the driving force to the clutch output shaft 74 side.

The clutch hydraulic chamber 5 of the hydraulic clutch 50
8, a clutch pressure (PCLU) that is changed according to various control modes (control modes) determined by the control unit 134 described later is applied.

The various control modes include, for example, a neutral mode (NEU) and a hold mode (HL).
D), a start mode includes a normal start mode (NST), a drive mode (DRV), and the like.

The neutral mode (NEU) is determined when the shift lever is in the parking position "P" or neutral "N" and the hydraulic clutch 50 is completely disengaged, and the clutch pressure to the hydraulic clutch 50 becomes zero. It is a state of.

The hold mode (HLD) is determined based on the position of the shift lever, the engine speed, the vehicle speed, and the state of depression of the accelerator pedal. That is, the hold mode (HL
D) is the condition that the shift lever position is drive “D”, low “L” or reverse “R”, and the engine speed (N
E) The condition of <1000 rpm and the rotation (vehicle speed) of the clutch output shaft 74 of the hydraulic clutch 50 (NCO) <8 km /
h and a driver demand switch 158 to be described later.
Is off, that is, when the accelerator pedal (not shown) is not depressed and the condition that the driver does not intend to drive the vehicle is satisfied. In the hold mode (HLD), the clutch pressure (PCLU) applied to the clutch hydraulic chamber 58 of the hydraulic clutch 50 is such that the target clutch pressure value (CPSP) is 4.5 kg / cm ² (creep pressure).
So that the clutch solenoid valve 10 described later
6 clutch solenoid duty output signal (OPW
CLU). The clutch solenoid duty output signal is a pulse signal output from the control means 134, and controls the operation of the clutch solenoid valve 106 by changing the duty ratio. This hold mode (HLD) is used when there is no driving intention of the vehicle.
Alternatively, this is the case where it is desired to decelerate during running to cut off the engine torque. The clutch pressure (PCLU) of the hydraulic clutch 50 hardly transmits engine torque, but is maintained at a low value such that the hydraulic clutch 50 is slightly connected.

In the normal start mode (NST), the position of the shift lever, the engine speed (NE) and the vehicle speed (NC)
O) and the state of depression of the accelerator pedal. That is, in the normal start mode (NST), the conditions of the shift lever position of drive "D", low "L" or reverse "R", the condition of vehicle speed (NCO) <8 km / h, and the accelerator pedal are depressed. And the condition that the driver demand switch 158 is turned on and the engine speed (NE) ≧
It is determined when the condition of 1000 rpm is satisfied.
In the normal start mode (NST), when the vehicle is started or when the hydraulic clutch 50 is to be engaged again after the clutch is disconnected, the clutch pressure (P) corresponding to the engine generated torque (clutch input torque) is increased.
CLU) act on the hydraulic clutch 50,
The clutch pressure is maintained at an appropriate value with a quick response in order to prevent the engine speed from rising and to start the vehicle smoothly.

The drive mode (DRV) is determined based on the position of the shift lever, the vehicle speed, and the clutch slip amount.
That is, in the drive mode (DVR), the shift lever position is a condition of drive "D", low "L" or reverse "R", a condition of vehicle speed (NCO) ≥ 8 km / h, and a clutch slip amount ≤ 20 rpm. Is determined when the condition is satisfied. In this drive mode (DRV), the vehicle shifts to a complete running state and the hydraulic clutch 50
Is fully connected (clutch lock-up state),
Alternatively, the hydraulic clutch 50 is substantially locked up at the time of transition from the normal start mode (NST), and when the vehicle completely transitions to the running state and the hydraulic clutch 50 is completely engaged, there is a margin enough to withstand engine torque. A high clutch pressure (line pressure) having a certain pressure is applied to the hydraulic clutch 50.

The speed of the continuously variable transmission 2 is controlled by a speed change control device 76 as shown in FIG.

The transmission control device 76 is provided with a line pressure passage 78 through which oil pressure-fed by the oil pump 24 is supplied to the driven hydraulic chamber 42 to apply a line pressure. One end of the line pressure passage 78 is connected to the oil pump 2.
4 and the other end is connected to the driven shaft side oil passage 46.

One end of a first oil passage 80 is connected in the middle of the line pressure passage 78. On the other end side of the first oil passage 80, a line pressure control valve 82 is provided. The line pressure control valve 82 controls the line pressure in the line pressure passage 78.

One side of the line pressure control valve 82 is provided with a second
One end of the oil passage 84 is connected. This second oil passage 84
A line solenoid valve 86 for controlling the operation of the line pressure control valve 82 is provided on the other end side.

The oil pump 24 and the first oil passage 80
In the middle of the line pressure passage 78 between the connection portions with
One end of the oil passage 88 is connected. This third oil passage 88
On the other end side, a ratio pressure control valve 90 is provided.
One end of a ratio pressure passage 92 is connected to the ratio pressure control valve 90. The other end of the ratio pressure passage 92 is connected to the drive shaft side oil passage 22 of the drive shaft 10.

The ratio pressure control valve 90 is connected to the drive pulley 4
This is for controlling a ratio pressure (primary pressure), which is a hydraulic pressure applied to the drive-side hydraulic chamber 18.

One side of the ratio pressure control valve 90 has a fourth
One end of the oil passage 94 is connected. This fourth oil passage 94
A ratio solenoid valve 96 for controlling the operation of the ratio pressure control valve 90 is provided at the other end of the valve.

One end of a fifth oil passage 98 is connected to the line pressure passage 78 between the connection portion of the first oil passage 80 and the oil passage 46 on the driven shaft side. On the other end side of the fifth oil passage 98, a clutch pressure control valve 100 is provided.

One end of a clutch pressure passage 102 is connected to the clutch pressure control valve 100. The other end of the clutch pressure passage 102 is connected to a driven shaft clutch oil passage 72 on the hydraulic clutch 50 side.

The clutch pressure control valve 100 controls a clutch pressure which is a hydraulic pressure applied to the clutch hydraulic chamber 58.

On one side of the clutch pressure control valve 100,
One end of the sixth oil passage 104 is connected. On the other end side of the sixth oil passage 104, a clutch solenoid valve 106 for controlling the operation of the clutch pressure control valve 100 is provided.

In the middle of the third oil passage 88, a seventh oil passage 10
8 is connected to one end. On the other end side of the seventh oil passage 108, one side of a constant pressure control valve 110 is provided.
The constant pressure control valve 110 is provided with a line pressure (generally 5 to 25 k
g / cm ² ) at a constant pressure (4-5 kg / cm ² ).

The other end of the constant pressure control valve 110 is connected to one end of an eighth oil passage 112. This eighth oil passage 11
The other end of 2 is branched into a ninth oil passage 114 and a tenth oil passage 116. The ninth oil passage 114 is connected to the line pressure control valve 8.
2 is connected to the other side. The tenth oil passage 116 is connected to the line solenoid valve 86.

In the middle of the eighth oil passage 112, one end of an eleventh oil passage 118 is connected. This eleventh
The other end of the oil passage 118 is branched into a twelfth oil passage 120 and a thirteenth oil passage 122. The twelfth oil passage 120 is connected to the other side of the ratio pressure control valve 90. 13th oilway 1
22 is connected to a ratio solenoid valve 96.

Further, one end of a fourteenth oil passage 124 is connected in the middle of the eighth oil passage 112. This 14th
The other end of the oil passage 124 is branched into a fifteenth oil passage 126 and a sixteenth oil passage 128. The fifteenth oil passage 126 is connected to the other side of the clutch pressure control valve 100. The sixteenth oil passage 128 is connected to the clutch solenoid valve 106.

In the middle of the clutch pressure passage 102, one end of a clutch pressure detection passage 130 is connected. At the other end of the clutch pressure detection passage 130, a hydraulic pressure sensor 132 for detecting the clutch pressure of the clutch pressure passage 102 is provided.

The line solenoid valve 86, the ratio solenoid valve 96, and the clutch solenoid valve 10
6 and the oil pressure sensor 132 are connected to a control means (ECM) 134
Has been contacted.

The control means 134 includes a drive shaft rotation sensor 136 for detecting the rotation of the drive shaft 10 as the engine speed (NE) of the internal combustion engine, and a driven shaft for detecting the rotation of the driven shaft 34 as the rotation of the clutch input shaft. A shaft rotation sensor 138,
An output shaft rotation sensor 140 that detects the rotation (NCO) of the clutch output shaft 74 as the vehicle speed is connected.

The drive shaft rotation sensor 136 detects the rotation of the drive shaft rotation detection gear 142 fixed to the drive shaft 10 on the rear surface of the drive side housing 20, and outputs a signal corresponding to the rotation of the drive shaft 10. 134.

The driven shaft rotation sensor 138 detects the rotation of the driven shaft rotation detecting gear 144 fixed to the driven shaft 34 on the rear side of the driven housing 44 and outputs a signal corresponding to the rotation of the driven shaft 34. 134.

The output shaft rotation sensor 140 has an output shaft rotation detecting gear 146 provided integrally with the clutch output shaft 74.
Rotation of the clutch output shaft 74 (vehicle speed)
(NCO) is output to the control means 134.

The control means 134 includes a shift lever position detection sensor 148 and a throttle opening sensor 150.
, An idle position switch 152, a brake switch 154, a power mode option switch 156,
A driver demand switch (DDT SW) 158 is communicated.

The shift lever position detecting sensor 148 detects the position of the shift lever, that is, the parking "P", the reverse "R", the neutral "N", the drive "D", and the low "L", and detects the signal. To the control means 134 to control the line pressure, the ratio pressure, and the clutch pressure required for each shift lever position.

The throttle opening sensor 150 detects the throttle opening (THR) state of a throttle valve (not shown), outputs a signal corresponding to the throttle opening (THR) to the control means 134, and outputs the signal to the control means 134. In this method, the engine torque is detected from the memory previously input to the program, and the target gear ratio and the target engine speed are determined.

The idle position switch 152 detects the fully opened state of the throttle where the throttle opening is the idling position and outputs a signal to the control means 134, and the control means 134 corrects the throttle opening sensor 150. This enhances the reliability of control.

The brake switch 154 detects whether or not the brake pedal is depressed and outputs a signal to the control means 134 so that the control means 134 determines the direction of control such as disconnecting the hydraulic clutch 50. is there.

Power mode option switch 156
Is used to make the performance of the vehicle sporty or economy, and outputs a signal to the control means 134 so that the control means 134 controls the ratio pressure and the like.

The driver demand switch 158 is operated according to the driver's intention to start, and the signal thereof is transmitted to the control means 1.
34.

The control means 134 inputs these various signals, and when the vehicle starts in the above various control modes or after the clutch disengages, the hydraulic clutch 50 which is the clutch again.
In the start mode (NST) in which the clutch output rotational speed (NCO) is engaged with the trigger value (NC).
At the time of (OTR) or more, the rotation radius of the belt 8 was changed to adjust the gear ratio (RATC) to decrease, and the mode was shifted from the start mode (NST) to the drive mode (DRV) in which the clutch was completely connected. (X in FIGS. 5 and 6)
The gear ratio limit value (RATC L) immediately after the transition to the drive mode (DRV) so as to suppress the engine speed (NE) assumed by the value of the gear ratio (RATC) at the first position.
INE) closer to the filtered target engine speed (NESPRF) which is the target engine speed.

The program of the control means 134 includes a gear ratio target value (R) as a function of the throttle opening (THR).
ATSP) (see FIG. 3) is input, and f (TH) for obtaining a gear ratio target value correction coefficient (ΔRATSP) as a function of the throttle opening (THR).
R) A curve (RSDLCV) map (see FIG. 4) is input.

The control means 134 operates in a normal start mode (NST) as shown in FIGS.
Is about to be completed, that is, in order to secure the starting drive force at low speed, the operation is not performed at low speed, and when the normal start mode (NST) is completed, the clutch output speed (NCO) At the Xo position when the trigger value (NCOTR), which is the clutch output speed trigger, is reached, that is, when the clutch output speed (NCO) is equal to or more than the trigger value (NCOTR), the turning radius of the belt 8 is changed.
The gear ratio (RATC) is gradually reduced from a fixed position of full low (F / L). This reduction amount of the gear ratio (RATC) is used to secure a predetermined driving force when the vehicle starts moving.
The value decreases as the throttle opening (THR) increases, and increases as the vehicle speed increases.

Next, the shift control of the continuously variable transmission 2 will be described with reference to the flowchart of FIG.

When the program starts in the control means 134 (step 202), it is first determined whether or not the normal start mode (NST) is set (step 20).
4).

If this step 204 is NO, it is determined whether or not a hold mode (HLD) is set (step 2).
06).

If YES in step 206,
The target gear ratio (RATSPH) in the hold mode is set as the target gear ratio (RATSP) (step 208), and the gear ratio control flag (RATMOD) is set (step 210). Then, the ratio solenoid duty (OPWRAT) Is calculated (step 212), and a return is made (step 214).

If NO in step 206, another shift control is performed (step 216), and the process is returned (step 214).

On the other hand, if step 204 is YES and the normal start mode (NST) is set, the target gear ratio (RATSP) = RATCV (T
HR), and a gear ratio target value correction coefficient (△ RATSP) = RSDLCV (TH
R) is determined (step 208). Where RATC
V is a RATSP = f (THR) curve, and RSDL
CV is a △ RATSP = f (THR) curve.

The relationship between the clutch output speed (NCO) and the clutch output speed trigger (NCOTR) is as follows:
It is determined whether NCO <NCOTR or NCO ≧ NCOTR (step 220). That is, this determination is made according to FIGS.
At the Xo position.

At step 220, NCO ≧ NCOTR
In the case of, the final correction value K of the gear ratio target value is calculated as K = △ RA
TSP × (NCO−NCOTR) is calculated (step 2
22) Then, the RATSP-K is changed to the gear ratio target value (RA
TSP), that is, RATSP-K → RATSP (step 224), and then the process proceeds to step 210.

In step 220, NCO <NCOTR
In this case, the gear ratio target value final correction value (K) is set to 0 (step 226), and the routine proceeds to step 224.

That is, the gear ratio (RATC) is shown in FIGS.
As shown in FIG.

The shift control of the continuously variable transmission 2 will be described with reference to the shift control block diagram of FIG.

The throttle opening (THR) is determined by the first map portion 302 having the map of FIG. 3 and the second map portion 302 having the map of FIG.
The data is input to the map unit 304 in parallel.

The gear ratio target value (RATSP) determined by the first map section 302 is output to the first calculation section 306.

The gear ratio target value correction coefficient (ΔRATSP) determined by the second map section 304 is output to a correction coefficient calculation section 308, where K = K
It is used for calculating ΔRATSP × (NCO−NCOTR). Here, K is a gear ratio target value final correction value.

The correction coefficient calculating section 308 is connected to a second switching section 310 having a second switch (SW2). In this second switching section 310, NCO <NC
OTR or NCO ≧ NCOTR is determined, and when NCO <NCOTR, the second switch (SW
2) While is connected to the zero side contact _{E 1} of "0" side, NC
In the case of O ≧ NCOTR is connected to the correction coefficient side contact _{E 2} which is contacted to the second switch (SW2) is correction coefficient calculating unit 308.

The second switch (SW2) is connected to the first switch (SW2).
The calculation unit 306 is communicated. This first calculation unit 306
In the above, calculation of a gear ratio target value (RATSP) and a gear ratio target value final correction value (K) is performed.

The first operation unit 306 is connected to a first switching unit 312 having a first switch (SW1). In the first switching section 312, the first switch (SW1) is in the control mode (CONTROL MOD MOD).
E) is operated according to the state, and the first switch (SW1) is set to the first state in the case of the normal start mode (NST).
While connected to the start-side contact E ₃ which contact the arithmetic unit 306, when the hold mode (HOL) is connected to the hold side contact E _4. The hold-side contact _{E 4,} processing unit 314 to RATSPH → RATSP are contacted.

The filter processing section 316 is connected to the first switch (SW1). The filtering section 316 filters the signal from the first switch (SW1).

The filter processor 316 is connected to a second calculator 318 for calculating a signal value from the filter processor 316 and a gear ratio (RATC).

The second operation unit 318 includes the PI control unit 3
20 have been contacted. This PI control unit 320
The signal from the arithmetic unit 318 is proportionally integrated and controlled.
The value obtained by performing the proportional-integral control is referred to as a ratio solenoid valve 96.
Solenoid Duty (OP
WRAT).

As a result, as shown in FIGS. 5 and 6, during the normal start mode (NST), the gear ratio (RATC)
The clutch output speed (NCO) is the trigger value (NCO
TR) When the vehicle is started with the turning radius of the belt 8 changed and adjusted so as to decrease, the normal start mode (NST) to the drive mode (DRV)
To the gear ratio limit value (RATC LIN
E) can be made closer to the target engine speed (NESPRF) after filtering, so that the gear ratio limit value (RATC
LINE) and the target engine speed after filtering (NESP)
RF), the shift control after shifting to the drive mode (DRV) is smooth, and the hydraulic clutch 50
, The engine speed (NE) after the connection becomes smooth, and it is possible to avoid the engine speed (NE) from rising, thereby improving the starting feeling and increasing the engine speed (NE). The occurrence of overshoot and undulation can be prevented beforehand.

As shown in FIG. 6, in the first half of the normal start mode (NST), the gear ratio (RAT)
Since C) is substantially fixed to full low (F / L), a sufficient driving force can be secured.

Further, in this embodiment, the control means 1
Only the 34 programs need to be changed, the configuration is simple and practically advantageous.

In this embodiment, the gear ratio (RATC) in the normal start mode (NST) is set.
As shown in FIG. 7, the speed ratio (RATC) is adjusted from the beginning of the normal start mode (NST) as shown in FIG.
And it is possible to set the small permissible lower R ₁ position than Fururo (F / L) and the engine speed lower than the speed ratio when (NE).

In FIG. 7, when shifting from the normal start mode (NSE) to the drive mode (DRV), the fixed gear ratio line (RATC LIN) is set.
E) is the target engine speed (N
The engine speed (N) is set closer to the ESPRF) side.
The blow-up of E) can be prevented.

[0096]

As is apparent from the above detailed description, according to the present invention, the clutch output speed during the start of the vehicle in various control modes or in the start mode in which the clutch is engaged again after the clutch disengages. Is adjusted to reduce the gear ratio by changing the radius of rotation of the belt when is greater than or equal to the trigger value, and is assumed by the gear ratio value at the time of shifting from this start mode to the drive mode in which the clutch is completely connected. Control means for bringing the speed ratio limit value immediately after the shift to the drive mode closer to the target engine speed side so as to suppress the engine speed. The engine speed is reduced, and the engine speed is suppressed from rising. Therefore, the starting of the vehicle is smooth and the starting feeling is reduced. Improved, also, capable of preventing occurrence of overshoot and the waviness of the engine speed in advance.

Further, the present invention can be implemented only by changing the program of the control means, has a simple configuration, and is practically advantageous.

[Brief description of the drawings]

FIG. 1 is a flowchart of shift control of a continuously variable transmission.

FIG. 2 is a block diagram of shift control of the continuously variable transmission.

FIG. 3 is a relationship diagram between a throttle opening and a gear ratio target value.

FIG. 4 is a relationship diagram between a throttle opening and a gear ratio target value correction coefficient.

FIG. 5 is a time chart in a case where a vehicle is started with a gear ratio adjusted during a normal start mode.

FIG. 6 is a partial time chart in a case where a vehicle is started with a gear ratio adjusted during a normal start mode.

FIG. 7 shows that the gear ratio is set to a constant value R during a normal start mode.
₆ is a time chart in a case where the vehicle is started while being fixed at ₁ .

FIG. 8 is a system configuration diagram of a shift control device of the continuously variable transmission.

FIG. 9 is a time chart of a conventional shift control.

FIG. 10 is a time chart of a conventional shift control.

FIG. 11 is a time chart when the vehicle is started with the gear ratio fixed to the full low position during the normal start mode in the related art.

[Explanation of symbols]

 2 Continuously Variable Transmission 4 Drive Pulley 6 Driven Pulley 8 Belt 50 Hydraulic Clutch 76 Shift Control Device 78 Line Pressure Passage 82 Line Pressure Control Valve 86 Line Solenoid Valve 90 Ratio Pressure Control Valve 92 Ratio Pressure Passage 96 Ratio Solenoid Valve 100 Clutch Pressure Control Valve 102 Clutch pressure oil passage 106 Clutch solenoid valve 134 Control means

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-238129 (JP, A) JP-A-2-146367 (JP, A) JP-A-64-44346 (JP, A) JP-A-3- 249463 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) F16H 59/00-61/12 F16H 61/16-61/24 F16H 63/40-63/48

Claims (1)

(57) [Claims] 1. A speed change control device for a continuously variable transmission for a vehicle, wherein a speed ratio is continuously changed by changing a rotation radius of a belt wound around a driving pulley and a driven pulley in various control modes. In a start mode, in which the vehicle is started in the control mode or the clutch is engaged again after the clutch is disengaged, the turning radius of the belt is changed when the clutch output speed is equal to or more than the trigger value.
In this drive mode, the gear ratio is adjusted so as to decrease, and the engine speed assumed in accordance with the value of the gear ratio when shifting from the start mode to the drive mode in which the clutch is completely engaged is suppressed. A shift control device for a continuously variable transmission, further comprising control means for bringing a speed ratio limit value immediately after the shift closer to a target engine speed side.