JP2000283282A - Control method for deceleration of automatic transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To securely shift gear to substantially maximum change gear ratio by providing a transmission path connection means adjustable torque capacity electronically at a rear step of a change gear part and controlling in such a way that torque capacity of the connection means is smaller than set torque capacity if change gear ratio when a vehicle stops does not reach substantially maximum change gear ratio. SOLUTION: A rear step clutch 20 such as an electromagnetic clutch is provided as a transmission path connection means adjustable torque capacity electronically at a rear step of 8 change gear part 8. The rear step clutch 20 is connected with a control means 22 constituting a controller at the time of deceleration. This control means 22 controls in such a manner that torque capacity of the rear step clutch 20 is smaller than set torque capacity if change gear ratio of the change gear part 8 does not reach substantially maximum change gear ratio when a vehicle speed is below set vehicle speed and a vehicle substantially stops at the time of deceleration of the vehicle. According to the control method at the time of deceleration, it is possible to securely shift change gear ratio of the change gear part 8 to substantially maximum change gear ratio when the vehicle stops substantially.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control method for an automatic transmission at the time of deceleration, and more particularly, to a method for surely changing the speed ratio of a transmission unit to a substantially maximum speed ratio when a vehicle is substantially stopped. ,
The present invention relates to a deceleration control method for an automatic transmission that can ensure a driving force at the next start and can accurately reflect a driving operation of a driver and can achieve a driving performance required by the driver.

[0002]

2. Description of the Related Art Some vehicles have an automatic transmission connected to a power source such as an engine or a motor mounted on the vehicle. Some automatic transmissions include a transmission unit including a driving pulley and a driven pulley, and a belt wound around the driving pulley and the driven pulley.

[0003] The automatic transmission is controlled by control means. Some control means perform control so that the speed ratio of the transmission unit becomes substantially the maximum speed ratio when the vehicle speed is substantially equal to or lower than the set vehicle speed when the vehicle is decelerated.

As such a deceleration control method for an automatic transmission, Japanese Patent Laid-Open Publication No. 63-268745 and Japanese Patent Laid-Open Publication
There is one disclosed in Japanese Patent No. 36837.

Japanese Unexamined Patent Application Publication No. 63-268745 discloses an automatic transmission having a slip-type starting clutch capable of arbitrarily controlling a transmission torque. When the rate of change over time is equal to or greater than an allowable value, the starting clutch is controlled from a completely engaged state to a slipping state or a disconnected state.

Japanese Unexamined Patent Publication No. 1-136837 discloses a technique for estimating an engine generated torque from a throttle opening and an engine speed, and correcting the estimated engine generated torque by a time rate of change of the engine speed. The hydraulic pressure in the load thrust control oil chamber provided on either the drive pulley or the driven pulley of the V-belt continuously variable transmission is adjusted to a hydraulic pressure corresponding to the corrected engine generated torque.

[0007]

When the vehicle is stopped after deceleration of the vehicle, in order to secure a driving force at the next start, the automatic transmission is shifted by the transmission unit until the next start. It is desirable to return the ratio to the maximum speed ratio at which the ratio is at the maximum deceleration state.

In this case, in an automatic transmission provided with a transmission portion capable of changing the gear ratio steplessly by a driving pulley, a driven pulley, and a belt, the pulley and belt are rotated to change the gear ratio. Need to be done. In addition, when the transmission path connecting means is provided at the preceding stage (drive source side) of the transmission unit, the rotation of the pulley and the belt connected to the drive wheels is stopped while the vehicle is stopped. is there.

As a method of coping with such a problem, a method of returning the gear ratio to the maximum gear ratio while the pulley and the belt are rotating before stopping is generally used. However, fuel consumption, drivability and system cost are reduced. Is disadvantageous.

Therefore, in the automatic transmission, a transmission path connecting means such as a clutch, a brake, a torque converter and the like is provided at a rear stage (on a driving wheel side) of the transmission section so that the pulley and the belt can be rotated even when the vehicle is stopped so that the speed can be changed. Some are provided.

When such an automatic transmission is improved or deployed in a so-called hybrid vehicle equipped with an engine and a motor as a power source, a transmission path connection is provided in a transmission path between the power source and the transmission. Means may be added.

However, in the case of such a system, when the vehicle is stopped, the transmission path connecting means added to the preceding stage of the transmission unit slips, and the transmission path connecting means at the rear stage of the transmission unit may not slip. There is. As a result, there is a problem that the belt and the pulley cannot be rotated, and the shift cannot be performed as described above.

In particular, when the transmission path connecting means added in front of the transmission section is a torque converter, such a tendency becomes remarkable as shown in FIG. In FIG. 4, while the vehicle is stopped at a vehicle speed of 0, the input rotation speed and the input speed of the rear clutch, which is the transmission path connecting means at the rear stage of the transmission unit, due to slippage of the torque converter which is the transmission path connection unit at the front stage of the transmission unit. The output rotational speed becomes zero, and the rear clutch does not slip so that shifting is impossible.

Therefore, when the vehicle is substantially stopped, the speed ratio of the transmission cannot be changed to the substantially maximum speed ratio, and the driving force at the next start cannot be secured. In contrast to the driving operation of the driver, the start of the vehicle may be sluggish, and the driving performance required by the driver may not be realized.

[0015]

SUMMARY OF THE INVENTION Therefore, in order to eliminate the above-mentioned disadvantages, the present invention provides an automatic transmission connected to a power source mounted on a vehicle, the transmission being driven by a driving pulley, a driven pulley, and a belt. An automatic transmission that is provided with a transmission unit capable of changing the ratio steplessly and that controls the transmission ratio of the transmission unit to be substantially the maximum transmission ratio when the vehicle speed is substantially stopped below a set vehicle speed during deceleration of the vehicle. In the control method during deceleration of the machine, a transmission path connecting means capable of electronically adjusting the torque capacity is provided at a subsequent stage of the transmission unit, and when the vehicle speed is substantially stopped at a vehicle speed equal to or less than a set vehicle speed at the time of deceleration of the vehicle, When the speed ratio of the transmission unit does not reach the substantially maximum speed ratio, the torque capacity of the transmission path connecting means is controlled to be smaller than the set torque capacity.

Further, in this deceleration control method, the torque capacity of the transmission path connecting means when the vehicle is started when the vehicle speed is substantially stopped below a set vehicle speed when the vehicle is decelerated. Is controlled to be larger than the set torque capacity.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A deceleration control method for an automatic transmission according to the present invention is characterized in that a torque capacity is electronically provided at a subsequent stage of a transmission section in which a gear ratio can be steplessly changed by a driving pulley, a driven pulley and a belt. Transmission path connecting means that can adjust the transmission path connecting means if the speed ratio of the transmission unit does not reach the substantially maximum speed ratio when the vehicle speed is substantially stopped below the set vehicle speed during deceleration of the vehicle. Is controlled to be smaller than the set torque capacity, so that when the vehicle is substantially stopped, the transmission path connecting means at the subsequent stage of the transmission unit is reliably slid, and the drive is performed by the sliding of the transmission path connecting means. The rotation of the side pulley and the driven side pulley and the belt can be enabled,
The gear ratio can be changed to a substantially maximum gear ratio.

In this deceleration control method, the torque capacity of the transmission path connection means is set when the vehicle is started when the vehicle speed is substantially stopped below the set vehicle speed when the vehicle is decelerated. By controlling the torque to be larger than the torque capacity, it is possible to transmit the driving force to the driving wheels by reducing slippage of the transmission path connecting means at the subsequent stage of the transmission unit when starting.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 3 show an embodiment of the present invention. In FIG. 2, reference numeral 2 denotes a drive source mounted on a vehicle (not shown), 4 denotes an automatic transmission, and 6 denotes drive wheels. The driving force of the driving source 2 such as an engine or a motor is converted in rotational speed and torque by the automatic transmission 4 and transmitted to the driving wheels 6.

The automatic transmission 4 is provided with a transmission unit 8 for converting a driving force. The transmission unit 8 includes the driving pulley 1
0 and a driven pulley 12 and a belt 14 wound around the driving pulley 10 and the driven pulley 12. The belt width is relatively increased or decreased by increasing or decreasing the groove width of the driving pulley 10 and the driven pulley 12. By changing the turning radius of No. 14, the gear ratio is changed steplessly.

In the preceding stage of the transmission section 8 (on the side of the driving source 2),
A torque converter 16 as a transmission path connecting means and a forward / reverse switching mechanism 18 for reversing the rotational direction of the driving force are provided. At the subsequent stage (on the drive wheel 6 side) of the transmission unit 8, as transmission path connecting means capable of electronically adjusting the torque capacity,
A rear clutch 20 such as an electromagnetic clutch is provided. Transmission path connecting means capable of electronically adjusting the torque capacity include hydraulic transmission path connection means, pneumatic transmission path connection means, electromagnetic powder type transmission path connection means, and a transmission path in which a clutch position adjusting means is attached to a manual clutch. Connection means and the like can be used.

The rear clutch 20 is connected to control means 22 constituting a deceleration control device. This control means 2
Reference numeral 2 denotes a vehicle speed sensor 24 for detecting a vehicle speed, an accelerator pedal sensor 26 for detecting a depression state of an accelerator pedal (not shown), a speed ratio sensor 28 for detecting a speed ratio of the transmission unit 8, an engine speed and a torque converter. A sensor 30 for detecting other signals such as 16 input rotation speeds and the like are connected.

The control means 22 controls the speed ratio of the transmission unit 8 in accordance with the driving state of the vehicle in accordance with the signals input from the sensors 24 to 30. Is controlled so that the transmission ratio of the transmission unit 8 becomes substantially the maximum transmission ratio.

When the vehicle speed is substantially stopped at a vehicle speed equal to or lower than a set vehicle speed during deceleration of the vehicle, the control means 22 determines whether the speed ratio of the transmission unit 8 has not reached the substantially maximum speed ratio.
The torque capacity of the rear clutch 20 is controlled to be smaller than the set torque capacity.

When the vehicle is started at a time when the vehicle speed is substantially equal to or lower than the set vehicle speed at the time of deceleration of the vehicle, the control means 22 changes the torque capacity of the rear clutch 20 from the set torque capacity. Is also controlled.

Next, deceleration control will be described with reference to FIG.

When the control is started (100), the control means 22 determines whether or not the vehicle speed is substantially equal to or lower than a set vehicle speed (102).

If the determination (102) is NO, other shift control processing is performed (104), other rear clutch control processing is performed (106), and the routine returns (10).
8).

If the determination (102) is YES, it is determined whether an accelerator pedal (not shown) has been depressed (110).

If the judgment (110) is YES, the process shifts to the process (104). This judgment (110) is N
In the case of O, it is determined whether or not the gear ratio is substantially the maximum gear ratio (full low) (112).

If the determination (112) is YES, a gear shift control process for maintaining the gear ratio at substantially the maximum gear ratio is performed (1).
14), and proceed to the processing (106).

If the determination (112) is NO, a gear shift control is performed to return the gear ratio to the substantially maximum gear ratio (116), and a process is performed in which the torque capacity of the rear clutch 20 is reduced to be smaller than the set torque capacity and the clutch is slipped. (118) and return (1)
08).

As described above, according to the control method during deceleration, the control unit 22 changes the speed ratio of the transmission unit 8 to the substantially maximum speed ratio when the vehicle speed is substantially equal to or lower than the set vehicle speed during vehicle deceleration. If not reached, the torque capacity of the rear clutch 20 is controlled to be smaller than the set torque capacity,
Further, when the vehicle is started at the time when the vehicle speed is substantially stopped below the set vehicle speed when the vehicle is decelerating, the torque capacity of the rear clutch 20 is controlled to be larger than the set torque capacity.

Since the purpose of the control for making the torque capacity of the rear clutch 20 smaller than the set torque capacity is to return the speed ratio of the transmission unit 8 to the substantially maximum speed ratio, the substantially maximum speed ratio is realized in the substantially stopped state. After this, it is not necessary to rotate the driving pulley 10, the driven pulley 12, and the belt 14.

That is, it is not necessary to slide the rear clutch 20 after the substantially maximum speed ratio is achieved in the substantially stopped state. Therefore, when the gear ratio is substantially the maximum gear ratio (full low) in the determination (112), the gear ratio is held at the substantially maximum gear ratio (114), and the process proceeds to other rear clutch control processing (106). .

The other rear-stage clutch control (106)
The control is such that the rear clutch 20 is brought into a half clutch state or the rear clutch 20 is brought into a complete clutch connected state after the clutch connection. At this time, the rear clutch 20
Is larger than a value equal to or less than the set torque capacity for surely sliding the rear clutch 20.

In this deceleration control method, control is performed to return the gear ratio to the substantially maximum gear ratio in the substantially stopped state, and the rear clutch 20 reliably slips at least until the gear ratio reaches the substantially maximum gear ratio. Control.

On the other hand, when the driver performs the starting operation, the transmission is controlled so as to reduce the slip of the rear clutch 20 regardless of the processing (118) in order to give priority to the transmission of the driving force to the driving wheels 6. I do. The start operation is determined (110).
Is determined based on the depression state of the accelerator pedal. The determination of the start operation may be during the operation of the accelerator pedal or during the non-operation of the brake pedal.

At a vehicle speed other than a substantially stopped state where the vehicle speed exceeds the set vehicle speed, even if the rear clutch 20 does not slide,
The gear ratio can be changed by rotating the driving pulley 10, the driven pulley 12, and the belt 14 in conjunction with the rotation of the driving wheel 6. Therefore, the rear clutch 20 is controlled so that slippage is eliminated.

When the automatic transmission 4 is selected to be in the non-running state (neutral state, parking state), the other rear clutch control processing (106) is generally released.

As shown in FIG. 3, the control method for the automatic transmission 4 at the time of deceleration, as shown in FIG. 20 is controlled so that there is a difference between the input rotational speed and the output rotational speed of the second clutch 20 so that the rear clutch 20 is reliably slid.
The slip of the rear clutch 20 enables the rotation of the driving pulley 10, the driven pulley 12, and the belt 14, and the speed ratio can be changed to a substantially maximum speed ratio.

Further, in this deceleration control method, the slipping is reduced by increasing the torque capacity of the rear clutch 20 at the rear of the transmission unit 8 at the time of starting, and the driving force is transmitted to the driving wheels 6. Can be.

Therefore, according to the deceleration control method, when the vehicle is substantially stopped, the speed ratio of the transmission unit 8 can be reliably shifted to the substantially maximum speed ratio, and the driving force at the next start is determined. , The driving operation of the driver can be faithfully reflected, and the driving performance required by the driver can be realized.

[0044]

As described above, according to the control method for automatic transmission during deceleration of the present invention, when the vehicle is substantially stopped, the transmission path connecting means at the rear stage of the transmission section is surely slid, and the transmission path connection is performed. The slippage of the means enables the rotation of the driving pulley, the driven pulley, and the belt, so that the gear ratio can be changed to a substantially maximum gear ratio.

In this deceleration control method, it is possible to reduce the slip of the transmission path connecting means at the subsequent stage of the transmission unit at the time of starting and transmit the driving force to the driving wheels.

For this reason, this deceleration control method can surely change the speed ratio of the transmission unit to the substantially maximum speed ratio when the vehicle is substantially stopped, and secures the driving force at the next start. Accordingly, the driving operation of the driver can be faithfully reflected, and the driving performance required by the driver can be realized.

[Brief description of the drawings]

FIG. 1 is a control flowchart of deceleration control according to an embodiment of the present invention.

FIG. 2 is a block diagram of a deceleration control device.

FIG. 3 is a timing chart of control during deceleration.

FIG. 4 is a timing chart of conventional control during deceleration.

[Explanation of symbols]

 Reference Signs List 2 drive source 4 automatic transmission 6 drive wheel 8 transmission unit 10 drive pulley 12 driven pulley 14 belt 16 torque converter 18 forward / reverse switching mechanism 20 rear clutch 22 control means 24 vehicle speed sensor 26 accelerator pedal sensor 28 gear ratio sensor 30 other Sensor

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Claims (2)

[Claims] An automatic transmission connected to a power source mounted on a vehicle is provided with a transmission portion capable of continuously changing a speed ratio by a driving pulley, a driven pulley, and a belt, when the vehicle decelerates. In a deceleration control method for an automatic transmission in which the speed ratio of the transmission unit is controlled to be substantially the maximum speed ratio when the vehicle speed is substantially stopped below a set vehicle speed, electronically controlling a torque at a subsequent stage of the transmission unit. A transmission path connecting means capable of adjusting a capacity is provided, and when the vehicle speed is substantially stopped at a vehicle speed equal to or less than a set vehicle speed during deceleration of the vehicle, the transmission is performed if the speed ratio of the transmission unit does not reach the approximately maximum speed ratio. A control method during deceleration of an automatic transmission, wherein the torque capacity of the path connecting means is controlled to be smaller than a set torque capacity. 2. The method according to claim 1, wherein when the vehicle is decelerated and the vehicle speed is substantially equal to or lower than a set vehicle speed and the vehicle is started, the torque capacity of the transmission path connecting means is made larger than the set torque capacity. 2. The deceleration control method for an automatic transmission according to claim 1, wherein the control is performed so as to be as follows.