JP2013245791A - Transmission control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transmission control device capable of securing acceleration performance after the completion of neutral idling control.SOLUTION: An engagement force of a lock-up clutch is increased when affordable hydraulic pressure of an oil pump reaches a predetermined value or above after the completion of neutral idling control.

Description

  The present invention relates to a transmission control device.

  Patent Document 1 below discloses a neutral idle control technique for releasing the forward clutch and stopping the engine torque when the vehicle is stopped.

JP 2004-52643 A

  When the vehicle starts, the neutral idle control ends, the forward clutch is engaged, and the lockup clutch of the torque converter is in a slip lockup state in which slip engagement is performed. The forward clutch and the lockup clutch are engaged by hydraulic pressure generated by an oil pump driven by the engine. However, immediately after the end of the neutral idle control, the engine speed is not sufficiently increased, and the hydraulic pressure generated by the oil pump is insufficient, so that the fastening force of the forward clutch may be reduced.

  In order to solve the above problems, in the present invention, after the neutral idle control is finished, the fastening force of the lockup clutch is increased when the oil pressure that can be supplied by the oil pump becomes a predetermined value or more.

  Therefore, acceleration performance after the end of neutral idle can be ensured.

FIG. 3 is a schematic diagram of a continuously variable transmission mechanism according to the first embodiment. FIG. 3 is a control block diagram according to the first embodiment. It is a time chart which shows the state of each element from the neutral idle control of Example 1 to after the end of neutral idle control.

[Example 1]
[Configuration of continuously variable transmission]
FIG. 1 is a schematic diagram of a continuously variable transmission mechanism 1. The continuously variable transmission mechanism 1 receives power from the engine output shaft 7a of the engine 7, shifts the rotational speed of the engine output shaft 7a, and transmits it to the drive wheels 8 via the drive shaft 80.
The continuously variable transmission mechanism 1 includes a torque converter 2 that is a starting element having a torque increasing function, a belt-type continuously variable transmission 3 that performs shifting, a low speed mode and a high speed mode as a forward travel stage, and a reverse mode as a reverse travel stage. A sub-transmission 4 that switches between and a terminal mechanism 6 that enables differential operation of the left and right drive wheels 8.

(Configuration of torque converter)
The torque converter 2 includes a pump impeller 20 that rotates integrally with the engine output shaft 7a, a turbine runner 21 provided to face the pump impeller 20, and a stator 22 provided between the pump impeller 20 and the turbine runner 21. And a lock-up clutch 23 that allows the engine output shaft 7a and the torque converter output shaft 2b to rotate together when engaged.

  The pump impeller 20 is connected to the engine output shaft 7a via the front cover 2a, and rotates integrally with the engine output shaft 7a. The turbine runner 21 is connected to the torque converter output shaft 2b and rotates integrally with the torque converter output shaft 2b. The stator 22 is supported on the transmission housing 93 via a one-way clutch 22a that allows rotation in only one direction relative to the transmission housing 93.

  The lockup clutch 23 is slidable in the axial direction with respect to the turbine runner 21. The lockup clutch 23 separates the lockup oil chamber 2c on the front cover 2a side and the converter oil chamber 2d on the turbine runner 21 side.

  The lock-up oil chamber 2c and the converter oil chamber 2d are supplied with hydraulic oil regulated by a control valve unit 200 described later. The lock-up clutch 23 is in a non-lock-up state, a lock-up standby state, a slip lock-up state, and a complete lock-up depending on a pressure difference (hereinafter referred to as a lock-up differential pressure) of the lock-up oil chamber 2c with respect to the hydraulic pressure in the converter oil chamber 2d. Controlled by the state.

  In the non-lock-up state, the lock-up differential pressure is set to negative (hereinafter, non-lock-up control). As a result, a force acts on the lockup clutch 23 in a direction away from the front cover 2a. In the lockup standby state, the lockup differential pressure is set to almost zero (hereinafter, lockup standby control). As a result, the lock-up clutch 23 is in a state where the force from the hydraulic oil is canceled out. In the slip lock-up state, the lock-up differential pressure is set to be positive (hereinafter, slip lock-up control). As a result, a force acts on the lock-up clutch 23 on the front cover 2a side, and the slip-up state between the lock-up clutch 23 and the front cover 2a is created by controlling the lock-up differential pressure. In the complete lockup state, the lockup differential pressure is set to be positive (hereinafter, complete lockup control). As a result, a force acts on the lockup clutch 23 on the front cover 2a side, and the lockup clutch 23 and the front cover 2a rotate together by controlling the lockup differential pressure.

  The pump impeller 20 is provided with a pump impeller side sprocket 20a so as to rotate integrally. An oil pump-side sprocket 5b is provided on the drive shaft 5a of the oil pump 5 so as to rotate integrally. A chain 5c is stretched between the pump impeller side sprocket 20a and the oil pump side sprocket 5b. That is, the oil pump 5 is driven by the engine 7.

  A counter gear mechanism 90 is provided between the torque converter 2 and the belt type continuously variable transmission 3. The counter gear mechanism 90 includes an input side counter gear 91 and an output side counter gear 92 that meshes with the input side counter gear 91. The input side counter gear 91 is provided so as to rotate integrally with the torque converter output shaft 2b, and the output side counter gear 92 is provided so as to rotate integrally with the transmission input shaft 3a.

(Configuration of belt type continuously variable transmission)
The belt type continuously variable transmission 3 includes a primary pulley 30 that rotates integrally with the transmission input shaft 3a, a secondary pulley 31 that rotates integrally with the transmission output shaft 3b, and a primary pulley 30 and a secondary pulley 31. And a belt 35 provided.
The primary pulley 30 includes a fixed sheave 30a provided with fixed movement in the axial direction with respect to the transmission input shaft 3a and a movable sheave 30b provided with movement in the axial direction with respect to the transmission input shaft 3a. ing. A primary hydraulic chamber 32 is provided on the back surface of the movable sheave 30b. The primary hydraulic chamber 32 communicates with the oil pump 5 via the control valve unit 200.

  The secondary pulley 31 includes a fixed sheave 31a provided with fixed movement in the axial direction with respect to the transmission output shaft 3b, and a movable sheave 31b provided with movement in the axial direction with respect to the transmission output shaft 3b. ing. A secondary pressure chamber 33 is provided on the back surface of the movable sheave 31b. The secondary pressure chamber 33 is provided with a spring 33a that urges the movable sheave 31b toward the fixed sheave 31a.

The belt 35 includes a V-shaped sheave surface 30c formed by the fixed sheave 30a and the movable sheave 30b of the primary pulley 30, and a V-shaped sheave surface 31c formed by the fixed sheave 31a and the movable sheave 31b of the secondary pulley 31. It is stretched over.
When the pressure in the primary hydraulic chamber 32 is low, the space between the fixed sheave 30a and the movable sheave 30b of the primary pulley 30 is wide, and the belt 35 is in contact with the inner peripheral side of the primary pulley 30. At this time, the space between the fixed sheave 31a and the movable sheave 31b of the secondary pulley 31 is narrow, and the belt 35 is in contact with the outer peripheral side of the primary pulley 30. That is, the belt type continuously variable transmission 3 decelerates and outputs the rotational speed of the transmission input shaft 3a to the transmission output shaft 3b.

  When the pressure in the primary hydraulic chamber 32 is high, the space between the fixed sheave 30a and the movable sheave 30b of the primary pulley 30 is narrow, and the belt 35 is in contact with the outer peripheral side of the primary pulley 30. At this time, the fixed sheave 31a of the secondary pulley 31 and the movable sheave 31b are wide, and the belt 35 is in contact with the inner peripheral side of the primary pulley 30. That is, the belt-type continuously variable transmission 3 increases the rotational speed of the transmission input shaft 3a to the transmission output shaft 3b and outputs it.

(Sub-transmission configuration)
The sub-transmission 4 includes a planetary gear mechanism 40, a low brake LB that is engaged in the low speed mode, a high clutch HC that is engaged in the high speed mode, and a reverse clutch RC that is engaged in the reverse mode.
The planetary gear mechanism 40 is a Ravigneaux type planetary gear mechanism, which is a front sun gear Sf that rotates integrally with the transmission output shaft 3b, a first pinion P1 that meshes with the front sun gear Sf, a second pinion P2 that meshes with the first pinion P1, The ring gear R meshes with the two-pinion P2, the rear sun gear Sr meshed with the second pinion P2, the first pinion P1, and the carrier C that rotatably supports the second pinion P2. The carrier C is connected to the auxiliary transmission output shaft 4a.

  The low brake LB is provided between the rear sun gear Sr and the case, and restricts the rotation of the rear sun gear Sr when fastened. The high clutch HC is provided between the sun gear S and the carrier C, and the sun gear S and the carrier C rotate integrally when fastened. The reverse brake RB is provided between the ring gear R and the case, and regulates the rotation of the ring gear R when fastened.

(Configuration of termination mechanism)
A terminal mechanism 6 is provided between the auxiliary transmission 4 and the drive wheel 8.
The end mechanism 6 is rotatably supported by a drive pinion 60 that rotates integrally with the auxiliary transmission output shaft 4a, a ring gear 61 that meshes with the drive pinion 60, a differential case 62 that rotates together with the ring gear 61, and the differential case 62. Differential pinion 63, left wheel side gear 64l that rotates integrally with left wheel drive shaft 80l connected to left drive wheel 8l, and right wheel side gear 64r that rotates integrally with right wheel drive shaft 80r connected to right drive wheel 8r. It is configured.

The rotation of the auxiliary transmission output shaft 4a is decelerated between the drive pinion 60 and the ring gear 61. The differential pinion 63 meshes with the left wheel side gear 64l and the right wheel side gear 64r, respectively, and enables operation between the left wheel side gear 64l and the right wheel side gear 64r.
A parking gear 65 is provided adjacent to the drive pinion 60. When the parking brake is operated, the drive pinion 60 and the parking gear 65 mesh with each other to restrict the rotation of the drive pinion 60.

[Configuration of control unit]
FIG. 2 is a control block diagram of an electronic control unit and a hydraulic control unit that control the continuously variable transmission mechanism 1.
The electronic control unit includes a continuously variable transmission controller 100, a neutral idle controller 300, and an engine controller 400.
The continuously variable transmission controller 100 includes accelerator pedal opening sensor 101 to accelerator pedal opening degree information, vehicle speed sensor 102 to vehicle speed information, primary speed sensor 103 to primary pulley 30 speed information, and secondary rotation. The rotational speed information of the secondary pulley 31 from the number sensor 104, the operating hydraulic pressure information in the continuously variable transmission mechanism 1 from the hydraulic sensor 105, the shift range position information selected by the driver from the inhibitor switch 106, and the brake pedal from the brake switch 107 Enter operation information.

The neutral idle controller 300 exchanges information with the continuously variable transmission controller 100.
The engine controller 400 independently controls the engine 7 by the accelerator pedal opening degree and the like, and controls the engine 7 in cooperation with the neutral idle controller 300.

(Continuously variable transmission control)
The continuously variable transmission controller 100 performs lockup control for controlling the lockup clutch 23 of the torque converter 2 to a non-lockup state, a lockup standby state, a slip lockup state, and a complete lockup state. That is, when neutral idle control, which will be described later, is being performed, the lockup state is controlled. Until the neutral idle control is canceled and the condition for sufficiently ensuring the oil pressure by the oil pump 5 is satisfied, the lockup standby state is controlled. The condition for ensuring sufficient oil pressure by the oil pump 5 is established, and the slip lock-up state is controlled until the vehicle speed satisfies the complete lock-up condition. When the vehicle speed satisfies the complete lockup condition, the vehicle is controlled to the complete lockup state.

The continuously variable transmission controller 100 performs line pressure control and speed ratio control of the belt type continuously variable transmission 3. That is, while performing the line pressure control to obtain the target line pressure according to the accelerator pedal opening, etc., the speed ratio control command for obtaining the target secondary rotational speed is determined by determining the target secondary rotational speed from the operating point based on the vehicle speed and the accelerator pedal opening. Output.
The continuously variable transmission controller 100 performs shift control of the auxiliary transmission 4. That is, it is determined whether the speed mode is the low speed mode or the high speed mode according to the driving point based on the vehicle speed and the accelerator pedal position, and the low brake LB is engaged in the low speed mode, and the high clutch HC is engaged in the high speed mode. Control to do. When the reverse range selected by the driver is selected, it is determined that the reverse mode is selected, and control is performed so that the reverse brake RB is engaged.

As a configuration of the hydraulic control unit, a control valve unit 200 is provided. The control valve unit 200 adjusts the hydraulic pressure of the hydraulic oil supplied from the oil pump 5 in accordance with a command from the continuously variable transmission controller 100 and supplies it to each device.
The control valve unit 200 performs lockup hydraulic pressure control of the torque converter 2. That is, at the time of a non-lockup control command from the continuously variable transmission controller 100, the converter hydraulic pressure is supplied to the lockup oil chamber 2c and the converter oil chamber 2d of the torque converter 2. The converter oil chamber 2d is supplied with hydraulic oil that is slightly lower in pressure than the hydraulic oil supplied to the lockup oil chamber 2c through the orifice. As a result, the hydraulic pressure in the converter oil chamber 2d becomes lower than the hydraulic pressure in the lockup oil chamber 2c, and the lockup clutch 23 is separated from the front cover 2a. When a lockup control command is issued from the continuously variable transmission controller 100, the converter hydraulic pressure is supplied to the converter oil chamber 2d of the torque converter 2, and the lockup oil chamber 2c communicates with the drain.

The control valve unit 200 performs gear ratio hydraulic control of the belt type continuously variable transmission 3. That is, in response to a gear ratio control command from the continuously variable transmission controller 100, the primary pressure is guided to the primary hydraulic chamber 32, and the target speed ratio is obtained by the belt type continuously variable transmission 3.
The control valve unit 200 performs transmission hydraulic pressure control of the auxiliary transmission 4. That is, when the low-speed mode command is issued from the continuously variable transmission controller 100, the low brake pressure is guided to the low brake LB of the auxiliary transmission 4. When the high-speed mode command is issued from the continuously variable transmission controller 100, the high clutch pressure is guided to the high clutch HC of the auxiliary transmission 4. At the time of reverse mode command from the continuously variable transmission controller 100, reverse brake pressure is guided to the reverse brake RB of the auxiliary transmission 4. In addition, if a gear shift command to the high speed mode is issued from the continuously variable transmission controller 100 when the low speed mode is selected, a reshuffling shift that supplies high clutch pressure to the high clutch HC is performed while releasing the low brake pressure of the low brake LB. . When a gear shift command to the low speed mode is issued from the continuously variable transmission controller 100 when the high speed mode is selected, a crossover gear shift that supplies low brake pressure to the low brake LB is performed while releasing the high clutch pressure of the high clutch HC.

(Neutral idle control)
The neutral idle control will be described. The position of the shift range input from the inhibitor switch 106 is the forward travel position (eg, “D” or “L” position), and the vehicle speed is substantially zero for a predetermined time (several seconds) with the brake pedal depressed. About) If it continues, it is determined that the neutral idle control condition is satisfied. When the neutral idle control condition is satisfied, the engaged high clutch HC or low brake LB is released, and the engine torque is reduced more than before the neutral idle condition is satisfied. As a result, it is possible to improve fuel efficiency by reducing the load on the engine 7 and also reducing the engine torque itself.

  If the brake pedal is released and the brake switch 107 is turned off during the neutral idle control, the neutral idle condition is not satisfied, and the released low brake LB is started. That is, when the driver's intention to start is detected, control for starting the vehicle is performed. The vehicle speed is generated when the low brake LB is engaged, but the engine torque is not increased according to the accelerator pedal opening until the vehicle speed exceeds the predetermined vehicle speed (hereinafter referred to as the torque down end vehicle speed). The engine torque is controlled so as to maintain the engine speed that tends to decrease as the load increases due to the fastening of the LB. As a result, it is possible to prevent the engine speed from being increased due to an increase in engine torque before the low brake LB is completely engaged.

(Lock-up clutch control)
The control of the lockup clutch 23 will be described in detail below.
<When the vehicle is stopped>
When the vehicle is stopped, the lock-up clutch 23 of the torque converter 2 is released and controlled to a non-lock-up state. As a result, the pump impeller 20 and the turbine runner 21 can be operated. It is controlled to the non-lock-up state even during neutral idle control.

<Normal vehicle start>
The control of the lockup clutch 23 when the vehicle starts before entering the above-described neutral idle control will be described. When the brake pedal is released, lockup standby control is performed. Slip lockup control is performed by controlling so that the engaging force of the lockup clutch 23 increases as the accelerator pedal is depressed and the vehicle speed increases. By performing slip lock-up control, the load is gradually increased to lower the engine speed and increase the speed on the belt-type continuously variable transmission 3 side. As a result, the rotation of the engine output shaft 7a and the torque converter output shaft 2b can be synchronized at an early stage to shift to complete lockup control. Therefore, the fuel consumption of the engine 7 can be improved while obtaining the torque increasing action by the torque converter 2. When the rotation of the engine output shaft 7a and the torque converter output shaft 2b are synchronized, complete lockup control is performed.

<When the vehicle starts after neutral idle control ends>
The control of the lockup clutch 23 when the vehicle starts after the neutral idle control is finished will be described. When the driver's intention to start is detected, the neutral idle control ends and lockup standby control is performed. When the above-mentioned normal vehicle starts, slip lock-up control is performed when the accelerator pedal is depressed. On the other hand, when starting the vehicle after the end of neutral idle control, lock-up standby control is performed until the vehicle speed is equal to or higher than the above-described torque-down end vehicle speed and the engine speed is equal to or higher than a predetermined speed (hereinafter referred to as a speed at which hydraulic pressure can be secured). maintain. When the vehicle speed is equal to or higher than the torque reduction end vehicle speed and the engine speed is equal to or higher than the speed at which the hydraulic pressure can be secured, slip lock-up control and complete lock-up control are performed in the same manner as during normal start. In this embodiment, the suppliable hydraulic pressure of the oil pump 5 is estimated from the engine speed, but it may be estimated from the rotational speed and discharge flow rate of the oil pump 5, or the discharge hydraulic pressure of the oil pump 5 is measured. Also good. In any case, when the estimated or measured result is equal to or greater than a predetermined value (a hydraulic pressure that can be engaged with the lockup clutch 23 while engaging the low brake LB, or a value corresponding thereto), the slip lockup control and Perform full lockup control.

[Action]
(Operation after neutral idle control)
During the neutral idle control, the engine torque is made lower than before the neutral idle condition is established. Even after the driver's intention to start is detected by turning off the brake switch 107 or the like, the engine speed is lower than the engine torque corresponding to the accelerator pedal opening until the vehicle speed becomes equal to or higher than the vehicle speed at which the torque reduction is finished. The engine torque is set. Therefore, immediately after the neutral idle control is finished, the engine speed is low, and the oil pump 5 driven by the engine 7 cannot generate a sufficiently high hydraulic pressure. In this state, if the low brake LB is engaged and the slip lockup control of the lockup clutch 23 is performed at the same time, the low brake pressure cannot be sufficiently secured, and the vehicle start performance may be lowered.
Therefore, in the first embodiment, after the neutral idle control is finished, the slip lock-up control is prohibited until the vehicle speed becomes equal to or higher than the torque reduction finished vehicle speed and the engine speed becomes equal to or higher than the oil pressure securing speed.

FIG. 3 is a time chart showing the state of each element from the neutral idle control to after the end of the neutral idle control.
At time t1, the depression of the brake pedal is released, the brake switch is turned off, and the driver's intention to start is detected. At this time, the low brake pressure starts to increase and the load on the engine 7 increases. However, since the engine torque is controlled in accordance with the increase in the load, the rotational speed of the engine output shaft 7a is kept substantially constant. In the torque converter 2, a differential is generated between the pump impeller 20 and the turbine runner 21, and the rotational speed of the torque converter output shaft 2b is smaller than the rotational speed of the engine output shaft 7a. The lockup clutch 23 is switched from non-lockup control to lockup standby control, and the lockup differential pressure is set from negative to substantially zero.

  At time t2, the accelerator pedal is depressed and the accelerator pedal opening increases. At this time, the low brake pressure further increases and vehicle speed begins to occur. However, at this time, the vehicle speed is less than the torque-down end vehicle speed V1, and the engine torque is controlled according to the load regardless of the accelerator pedal opening, so the rotation speed of the engine output shaft 7a is kept almost constant. . Further, the lockup standby control is continued, and the lockup differential pressure is set to substantially zero.

  At time t3, the vehicle speed becomes equal to or higher than the torque reduction end vehicle speed V1. Therefore, the engine torque is set according to the accelerator pedal opening, and the rotational speed of the engine output shaft 7a is also increased. However, at this time, since the engine speed is less than the rotation speed R1 at which the hydraulic pressure can be secured, the lockup standby control is continued and the lockup differential pressure is set to substantially zero.

At time t4, the engine speed is equal to or higher than the rotation speed R1 at which the hydraulic pressure can be secured. Therefore, the lockup standby control is switched to the slip lockup control, and the lockup differential pressure increases according to the vehicle speed. By performing slip lock-up control, the load is gradually increased to lower the engine speed and increase the speed of the torque converter output shaft 2b.
At time t5, the rotation of the engine output shaft 7a and the torque converter output shaft 2b synchronizes and shifts to complete lockup control.

[effect]
The engine 7, the torque converter 2 having the lock-up clutch 23, the belt-type automatic transmission 3 (transmission), and the low brake LB (starting friction element) for connecting and disconnecting power transmission between the engine 3 and the drive wheels 8 ), The oil pump 5 that supplies hydraulic pressure to the lockup clutch 23 and the low brake LB by driving the engine 7, the lockup clutch 23 is released when the vehicle is stopped, and the lockup clutch 23 is increased as the vehicle speed increases when the vehicle travels. Continuously variable transmission controller 100 (lock-up clutch control means) that controls so that the fastening force of the vehicle is increased, and lowering the fastening force of the low brake LB when the vehicle is stopped than the fastening force when the vehicle is running, Neutral idle control that lowers the engine torque than before lowering the low brake LB engagement force after reducing the engagement force The continuously variable transmission controller 100 locks up when the available hydraulic pressure of the oil pump 5 exceeds a predetermined value after the neutral idle control is completed. The fastening force of the clutch 23 was increased.
Therefore, when the engine speed is low immediately after the end of the neutral idle control and the oil pump 5 cannot generate a sufficiently high hydraulic pressure, the slip lockup control of the lockup clutch 23 is not performed and the low brake LB is engaged. Priority can be given. For this reason, it is possible to ensure the vehicle start performance by sufficiently securing the low brake pressure when the vehicle starts.

[Other Examples]
As described above, the present invention has been described based on the first embodiment. However, the specific configuration of each invention is not limited to the first embodiment, and even if there is a design change or the like without departing from the gist of the present invention. Are included in the present invention. For example, in the first embodiment, the driver's intention to start is detected by turning off the brake switch 107, but it may be detected by reducing the brake pedal depression amount, or the accelerator pedal depression is started. This may be detected, and is not particularly limited. It is also possible to carry out only when it is detected that the brake switch 107 is turned off and the depression of the accelerator pedal is detected within a predetermined time (for example, within the time required to engage the low brake LB). It is.

2 Torque converter
3 Belt type automatic transmission (transmission)
5 Oil pump
7 Engine
23 Lock-up clutch
100 continuously variable transmission controller (lock-up clutch control means)
300 Neutral idle controller (neutral idle control means)
LB Low brake (starting friction element)

Claims (2)

Engine,
A torque converter having a lock-up clutch;
A transmission,
A starting friction element for connecting and disconnecting power transmission between the engine and the drive wheel;
An oil pump that supplies hydraulic pressure to the lock-up clutch and the starting friction element by driving the engine;
Lockup clutch control means for releasing the lockup clutch when the vehicle is stopped and controlling the fastening force of the lockup clutch to be increased in accordance with an increase in vehicle speed when the vehicle is running;
When the vehicle is stopped, the fastening force of the starting friction element is made lower than the fastening force when the vehicle is running, and after the fastening force of the starting friction element is reduced, the engine is more than before the fastening force of the starting friction element is reduced. Neutral idle control means for performing neutral idle control to reduce torque;
Have
The transmission control according to claim 1, wherein the lockup clutch control means increases the fastening force of the lockup clutch when the oil pressure that can be supplied by the oil pump becomes a predetermined value or more after the neutral idle control is finished. apparatus. 2. The transmission control apparatus according to claim 1, wherein the predetermined value is a hydraulic pressure capable of engaging the lockup clutch while engaging the starting friction element.

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