JP2003202076A - Control device of automatic transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent torque release from generating even if vehicle speed is not actually at 0 km/h, in a control device of an automatic transmission for executing a pseudo neutral control. <P>SOLUTION: At time t1, the control device of the automatic transmission starts an estimation control when the vehicle speed is actually estimated to be 0 km/h and other conditions including a brake being pressed on are satisfied. In the embodiment, at the same time to start the estimation control, pressure of a forward main clutch is decreased by a predetermined pressure. Then, in a predetermined period of time to terminate the estimation control (time t<SB>3</SB>), the main clutch pressure is controlled so that the engaging state of the forward main clutch changes from a complete engaging state to an engaging area just before a sliding engagement. Hence, sliding engagement is not generated at the forward clutch even if the vehicle speed is not 0 km/h, generation of torque release can be prevented during the predetermined period of time in which the estimation control is executed. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an automatic transmission that carries out pseudo-neutral control.

[0002]

2. Description of the Related Art In an automatic transmission for automobiles, the power of an engine is transmitted to an input shaft of a speed change mechanism via a torque converter, the speed change mechanism is used to shift the speed, and the power is transmitted to an output shaft to rotationally drive a drive shaft. I have to. The most common speed change mechanism is to arrange a plurality of gear elements between an input shaft and an output shaft to form a plurality of power transmission paths having different speed ratios between the input shaft and the output shaft. Friction engagement and disengagement of clutches and brakes are selectively switched in the transmission path, and the power transmission path between the input and output shafts is switched to switch the gear ratio.

By the way, in such an automatic transmission, a P (parking) range, an R (reverse) range,
N (neutral) range, D (drive) range, S
It is possible to select the (second) range, the L (low) range, or the like. For example, when the N range is switched to the D range by the shift lever, the rotation of the engine in the idling state is performed via the torque converter. The creep phenomenon occurs in which the vehicle is gradually transmitted to the transmission without even depressing the accelerator pedal.

On the other hand, in the technique disclosed in Japanese Patent No. 2804229, the D range, S range, and L range (hereinafter referred to as "forward range") for moving the vehicle forward are selected, and the accelerator pedal is used. The vehicle is released, the brake pedal is depressed, and the vehicle speed is substantially “0 km”.
/ H "is detected, a technique related to pseudo neutral control is known in which a forward clutch, which is engaged during forward traveling of the transmission, that is, a low clutch is slipped to form a pseudo neutral state. ing.

Generally, the purpose of forming this pseudo neutral state is to reduce the engaging force as the low clutch is engaged to make the slip engagement, thereby reducing the input / output rotational speed difference of the torque converter. To reduce torque loss. That is, it is intended to reduce fuel consumption by reducing torque cross.

Further, when the accelerator is depressed to return from the pseudo-neutral state to the normal operation mode, if the piston stroke of the low clutch is large, the engine will blow up when the low clutch is re-engaged. Therefore, in the pseudo neutral state, the piston stroke of the low clutch is set to 0 to suppress the response delay when the low clutch is re-engaged. Therefore, the target engagement area of the low clutch is extremely narrow, and therefore the control value of the control valve for controlling the engagement state of the low clutch by the hydraulic pressure is naturally narrow.

By the way, in the pseudo-neutral control disclosed in the above-mentioned Japanese Patent No. 2804229, as conditions for starting the pseudo-neutral control, the brake pedal is depressed, the vehicle speed is "0 km / h", and the throttle opening is made. The pseudo-neutral control is started under the condition that the degree θ is equal to or less than the predetermined opening degree and the temperature of the oil is equal to or higher than the predetermined temperature. Note that in this technology, the vehicle speed is "0.
As a specific method for estimating the km / h ", the degree of deceleration of the vehicle speed at a certain time is detected, and the vehicle speed is estimated to be" 0 km / h "based on the degree of deceleration at this time. When all the above conditions are satisfied, the start condition of the pseudo-neutral control is satisfied, and as the prospective control, the hydraulic pressure is reduced by ΔP for each predetermined period Δt so that the low clutch is slippingly engaged.

[0008]

However, when the driver changes the degree of depression of the brake,
As in the technology of Japanese Patent No. 2804229, the vehicle speed is "0k".
If the vehicle speed is not actually “0 km / h” when the m / h ”is estimated, there is a possibility that the vehicle speed will be erroneously determined to be“ 0 km / h ”. Even if the vehicle speed is not “0 km / h”, there is a possibility that the starting condition of the pseudo neutral control is satisfied and the pressure is reduced by a predetermined pressure ΔP. When the low clutch starts slipping engagement even though the speed is not 0 km / h ”, torque loss may occur and the drivability may be deteriorated.

Further, if the vehicle speed sensor is used to detect the actual vehicle speed, the sensor output near the speed "0 km / h" is fixed. That is, "0k" in the vehicle speed sensor
Since the reliability of the sensor is low in the m / h ”detection, it is difficult to accurately detect the time when the vehicle speed becomes“ 0 km / h ”, and the same inconvenience as in the case where the vehicle speed is estimated may occur. .

Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to reduce drivability due to torque loss even if the vehicle speed does not actually become "0 km / h". An object of the present invention is to provide a control device for an automatic transmission that can prevent the above.

[0011]

Therefore, as in the invention of claim 1, the prospective control means determines the first hydraulic pressure control for a predetermined period after the prospective control start determining means determines to start predictive control. The first hydraulic control valve is adjusted by the valve control means so that the forward clutch is brought into the engaged state immediately before the sliding engagement occurs.

By controlling the first hydraulic control valve in this way, even if the vehicle speed is not actually "0 km / h" during the predetermined period after the start condition of the prospective control is satisfied, the forward control is always performed. Since the clutch is controlled in the engaged state immediately before the slipping engagement occurs, it is possible to prevent the torque loss from occurring and prevent the drivability from deteriorating.
Then, after that, the transition control unit and the steady control unit control the engagement state of the forward clutch to the slip engagement immediately before the clutch is released, thereby forming the pseudo neutral state.

In the invention of claim 2, claim 1
The predictive control start determining means is a state in which the brake of the vehicle detected by the brake state detecting means is depressed, the throttle opening detected by the throttle opening detecting means is in a fully closed position, or the stop state is detected. The start of the predictive control may be determined based on one or more conditions of the stopped state of the vehicle detected or estimated by the means.

According to the third aspect of the present invention, there is provided learning means for learning a control value for adjusting the first hydraulic control valve for forming the pseudo-neutral state by the steady control means, and the forward movement is provided. A control value for adjusting the first hydraulic control valve by the first hydraulic control valve control means so that the clutch for clutch is in an engaged state immediately before the slipping engagement is learned by the learning means. It is set based on the learned value.

The control value for adjusting the first hydraulic control valve for forming the pseudo-neutral state is a signal area immediately before the forward clutch is released as the forward clutch engagement state, in other words, the engagement start. Since the control is performed so as to be in the region, the engagement characteristic from the engagement start region of the forward clutch to the complete engagement can be known. Therefore, based on this characteristic, the first state is set so that the engaged state immediately before the sliding engagement occurs.
It becomes possible to control the hydraulic control valve.

By the way, in the invention of claim 4, when the predictive control start determining means determines that the condition is the start condition of the predictive control, the predictive control is performed by the second hydraulic control valve control means. Engage the hydraulic control valve.

As a result, the reverse brake is engaged, so that it is possible to prevent the vehicle from moving backward even if the vehicle is stopped on an uphill road.

According to the fifth aspect of the present invention, when the turbine rotation speed detected by the turbine rotation speed detecting means changes during execution of the predictive control, the forward clutch is engaged immediately before the slip engagement occurs. The control value for adjusting the first hydraulic control valve by the first hydraulic control valve control means so as to be in the state is learned to the side that prevents the occurrence of sliding engagement.

As a result, even if the slipping engagement occurs within a predetermined period after the prospective control is started, the learning means can
Since the control value can be learned on the side that prevents the occurrence of slipping engagement, it is possible to prevent the occurrence of slipping engagement in the future predictive control from the next time onward, and also for forward movement against individual differences and changes over time. It is possible to prevent slipping engagement from occurring in the clutch.

According to the sixth aspect of the present invention, when the output of the vehicle speed sensor is detected within a predetermined period after the predictive control start determining means determines that the predictive control is started, the predictive control is ended and the predictive control is started. It is better to execute the judgment again.

[0021]

<First Embodiment> A first embodiment of the present invention will be described below with reference to the drawings.

First, a schematic configuration diagram of the automatic transmission 11 will be described with reference to FIGS. 1 and 2. As shown in FIG. 2, the torque converter 12 is provided on the output shaft of the engine (not shown).
Of the torque converter 12 is connected to a hydraulically driven transmission gear mechanism 15 (transmission mechanism). Inside the torque converter 12, a pump impeller 31 and a turbine liner 32 that form a fluid coupling are provided to face each other, and a stator 33 that rectifies the flow of oil is provided between the pump impeller 31 and the turbine liner 32. Has been. Pump impeller 31
Is connected to the input shaft 13 of the torque converter 12, and the turbine liner 32 is connected to the output shaft 1 of the torque converter 12.
Connected to four.

Further, the torque converter 12 is provided with a lock-up clutch 16 for engaging or disengaging between the input shaft 13 side and the output shaft 14 side. The crankshaft 13, which is the output shaft from the engine,
It is transmitted to the turbine shaft 14 via the torque converter 12. The turbine shaft 14 has a transmission gear mechanism 15
The gear ratio of the gear shift mechanism 15 is switched by switching between a plurality of clutches and each brake in the front planetary gear 23 and the rear planetary gear 22 of the shift gear mechanism 15. on the other hand,
The reduction drive shaft 35 includes the ring gear of the front planetary gear 23 and the rear planetary gear 2.
It is connected to two carriers.

A reverse clutch RC, a high clutch HC, and a low clutch LC are provided as each clutch which is a friction engagement element for switching a plurality of shift speeds in the two planetary gears 22 and 23, and each brake is a 2 & 4 brake. (Hereinafter, brake 2 & 4B), low & reverse brake (hereinafter, brake L & RB), and low one-way clutch 34 are provided.

Incidentally, FIG. 3 shows the clutch R of the 4-speed automatic transmission.
The combination of C, HC, LC, and the engagement of the brakes 2 & 4B, L & RB indicates the clutch and brake held in the engaged state (torque transmission state) at the gear position, and the unmarked release. It shows the state. Further, the ⊚ mark indicates that the vehicle is engaged only when the corresponding drive is performed, and the Δ mark indicates that the vehicle is released only when the vehicle starts and is engaged when the vehicle speed exceeds a predetermined speed. For example, in the case of downshifting from the third speed to the second speed, by releasing the clutch HC among the two clutches HC and LC held in the engaged state at the third speed and newly engaging the brakes 2 & 4B. Downshift to second gear. When shifting up from the 3rd speed to the 4th speed, one of the two clutches HC and LC held in the engaged state at the 3rd speed is disengaged, and instead, the brakes 2 & 4B are activated. When engaged, it shifts up to fourth speed.

As shown in FIG. 1, the speed change gear mechanism 15 includes
A hydraulic pump 18 driven by engine power is provided,
A hydraulic control circuit 17 is provided in an oil pan (not shown) that stores hydraulic oil. The hydraulic control circuit 17 includes a line pressure control circuit 19, an automatic shift control circuit 20, a lockup control circuit 21, a manual switching valve 26, and the like, and the hydraulic oil pumped up from the oil pan by the hydraulic pump 18 is line pressure controlled. It is supplied to the automatic shift control circuit 20 and the lockup control circuit 21 via the circuit 19. The line pressure control circuit 19 is provided with a hydraulic control valve (not shown) for controlling the line pressure for controlling the hydraulic pressure from the hydraulic pump 18 to a predetermined line pressure.
Are the clutches RC, HC, LC of the transmission gear mechanism 15.
And a plurality of shift hydraulic control valves (not shown) for controlling the hydraulic pressure supplied to the brakes 2 & 4B and L & LB. This hydraulic control valve has a normally open configuration, and each clutch RC, HC, LC and each brake 2 & 4 is used.
When it is desired to cut the hydraulic pressure supplied to B, L & RB, the energization of the hydraulic control valve is set to 100% duty.

Further, the lockup control circuit 21 is provided with a lockup control hydraulic control valve (not shown) for controlling the hydraulic pressure supplied to the lockup clutch 16. Further, between the line pressure control circuit 19 and the automatic shift control circuit 20, there is provided a manual switching valve 26 that is switched in conjunction with the operation of the shift lever 25. When the shift lever 25 is operated to the N range or the P range, even if the hydraulic control valve of the automatic shift control circuit 20 is deenergized (OFF), the manual switching valve 26 allows the shift gear mechanism 15 to operate. The hydraulic pressure supplied to the switch is switched so as to bring the transmission gear mechanism 15 into a neutral state.

On the other hand, the engine has a crankshaft 1
Crank rotation speed sensor 2 for detecting rotation speed Ne of 3
7, the transmission gear mechanism 15 includes a turbine rotation speed sensor 28 that detects a rotation speed Nt of the turbine shaft 14, and a reduction rotation speed sensor that detects a rotation speed No of the reduction drive shaft 35 from the transmission gear mechanism 15. 29 are provided.

Output signals from these various sensors are output to an automatic transmission electronic control circuit (hereinafter referred to as "AT-ECU") 3
Input to 0. The AT-ECU 30 is mainly composed of a microcomputer. This AT-ECU
Reference numeral 30 denotes the speed change gear mechanism 1 according to a preset speed change pattern of FIG. 3 stored in a built-in ROM (storage medium).
In order to perform the shift of No. 5, the energization of each hydraulic control valve of the automatic shift control circuit 20 is controlled according to the operation position of the shift lever 25 and the operating conditions (throttle opening, vehicle speed, etc.).
By energizing each hydraulic control valve, engagement / release of each clutch RC, HC, LC and each brake 2 & 4B, L & RB of the speed change gear mechanism 15 is switched, and a combination of gears for transmitting power is switched. Thus, the gear ratio of the transmission gear mechanism 15 is switched. Below, the hydraulic pressure to the clutch LC is the main clutch pressure, the hydraulic pressure to the brakes 2 & 4B is the hill hold pressure, and the control for setting the opening of the hydraulic control valve for adjusting these hydraulic pressures is the duty (hereinafter , DUTY) control. Further, the differential rotational speed between the input side and the output side of the torque converter 12, that is, the differential rotational speed between the rotational speed Ne of the crankshaft 13 and the rotational speed Nt of the turbine shaft 14 will be referred to as a slip amount for description.

In the automatic transmission constructed as described above, the pseudo neutral state is formed in this embodiment. The pseudo-neutral state has two purposes: to prevent a response delay that occurs when the clutch LC is re-engaged and to prevent the torque converter 12 from consuming torque, that is, to suppress deterioration of fuel consumption. The slip amount is controlled to a desired value. At this time, the desired slip amount is set to, for example, 100 rpm, thereby reducing the torque consumed by the torque converter 12 and suppressing the load on the engine from deteriorating the fuel consumption. By controlling the piston stroke of the clutch LC to be small, it is intended to prevent a response delay at the time of re-engagement of the low clutch.

Control of the pseudo-neutral state will now be described with reference to the time chart of FIG. 4 and the pseudo-neutral control routine of FIG. Pseudo-neutral control consists of three controls of predictive control, transient control, and steady control, and an outline of each of these three controls will be described. First, step S100 of the flowchart of FIG.
At, it is determined whether or not the start condition of the prospective control is satisfied. The starting condition of the predictive control is that the brake signal is turned on by the driver depressing the brake as shown in FIG. 4A, and the signal from the throttle sensor not shown as shown in FIG. 4B. Is 0
That is, as shown in FIG. 4C, the vehicle speed is “0 km.
/ H ", etc. In the present embodiment,
It is implemented by estimating that the vehicle speed is “0 km / h”.

If these conditions are satisfied, step S100 of FIG. 5 is affirmed (Yes), and step S100
Proceed to 200 and execute the prospective control. Here, the purpose of the prospective control will be described, only the outline of the control will be described, and the detailed description will be given later. The predictive control is a control that is executed from a time T1 in the time chart of FIG. 4 in a preset predetermined period (until a time T2 in FIG. 4 is reached), and the slip engagement is set as the engagement state of the clutch LC. Bring it into the engaged state immediately before it occurs, and brake L &
The control is executed for the two purposes of completely engaging the RB.

The purpose of controlling the engagement state of the clutch LC to be the engagement region immediately before the slipping engagement occurs is that torque loss occurs even if the actual vehicle speed is not "0 km / h". This is to prevent this.

Further, the predetermined period in which the prospective control is carried out is preset for the following purpose. Even if the vehicle speed is estimated to be “0 km / h” when the driver's brake depression degree is changed, the vehicle speed may not be actually “0 km / h”. Even in such a case, in the present embodiment, the engagement state of the clutch LC is set to a value immediately before the slipping engagement occurs, so that the torque loss does not occur. However, when the predetermined period is set to be short, the transient / steady state control described below is executed and slip occurs as the engaged state of the clutch LC. Therefore, when the actual vehicle speed is not “0 km / h” Torque loss occurs. Therefore, during this predetermined period, the vehicle speed is always "0k" even if the degree of depression of the brake is changed.
It is necessary to set the period of m / h ". After this period has elapsed, the transient / steady state control start condition is satisfied.

An outline of the prospective control is shown in FIG. 4 (f).
As shown in, the control value of the target main clutch pressure with respect to the clutch LC is the predetermined DUT at the same time as the start (time T1).
By setting Y larger, the actual main clutch pressure is reduced by a predetermined pressure. Then, by increasing the predetermined DUTY thereafter, the pressure is gradually reduced by a pressure sufficiently smaller than the predetermined pressure so that the pressure immediately before the slip engagement does not occur in the clutch LC at the end of the predetermined period of the prospective control is obtained. Set the main clutch pressure control DUTY. In addition,
Since the pressure at which the slip engagement does not occur is a value at which the slip engagement does not occur when the clutch LC is in the engaged state, even if the actual vehicle speed is not “0 km / h”. It is possible to prevent torque loss.

In this way, the control DU for the clutch LC is
The reason for setting TY is that the vehicle speed is presumed to be “0 km / h” and the clutch LC is controlled in an engagement region where slip engagement does not occur quickly, but slip engagement occurs. If the main clutch pressure is instantly reduced in the engagement area where it does not occur, the hydraulic pressure becomes unstable,
The engagement state becomes unstable. Therefore, in order to prevent the hydraulic pressure from becoming unstable, in the present embodiment, as described above, the hydraulic pressure is gradually reduced for the purpose of stabilizing the hydraulic pressure after reducing the predetermined pressure so that no slip occurs. The control DUTY is set so that the engagement area becomes a certain extent. Further, the control DUTY of the hill hold pressure shown in FIG. 4 (g) shows a control value for the hydraulic control valve of the brakes 2 & 4B, and the control DUTY is set to 0 in order to perform rapid oil filling of the brakes 2 & 4B at time T1. Set to% to instantly increase the hydraulic pressure. When the rapid filling of the hydraulic pressure is completed, a predetermined control DUTY is once set to reduce the hill hold pressure, and then the control DUTY is gradually set to gradually increase the hill hold pressure.

Then, the predetermined period ends (time T in FIG. 4).
2) Then, when the execution condition of the transient / steady state control is satisfied, as shown in FIG.
The prospective control execution condition of step S100 is negative (N
O) and the process proceeds to step S300. Then, in step S300, the transient / steady state control start condition is already satisfied, so the determination here is affirmative (YES), and the routine proceeds to step S400, where the transient / steady state control is executed.

As described above, the purpose of the pseudo-neutral control is to set the slip amount to, for example, 100 rpm to reduce the load on the engine to improve the fuel consumption and to set the piston stroke of the clutch LC to zero. It is intended to suppress a response delay at the time of re-engagement. In order to achieve these two purposes, the control area of the engaged state of the clutch LC is controlled to an extremely narrow control area. Therefore, in order to control the clutch LC to this target engagement region, transient / steady control is started at time T2. When this transient / steady state control is started, the target slip amount is set by a different setting method depending on the degree of progress of the control. Then, feedback control of the main clutch pressure control DUTY of FIG. 4 (f) is performed based on the deviation between the target slip amount and the actual slip amount to achieve both responsiveness and stability and the clutch LC with high accuracy.
The engagement state of can be controlled. Then, when the engagement state of the clutch LC reaches the target engagement state, steady control is executed at time T3 to maintain this engagement state. As described above, by learning the average main clutch pressure during the steady control performed after time T3 in FIG. 4, the clutch LC is brought into the engagement state immediately before the slip engagement occurs in the prospective control. Control DUTY is set.

As described above, the slip amount is, for example, 1
By controlling the speed to be 00 rpm, it is possible to reduce the torque consumed by the torque converter 12 and control the pseudo neutral state in consideration of the response delay at the time of re-engagement. By the way, when the driver depresses the accelerator pedal to shift from the driving state to the traveling mode from the driving state, step S5 in FIG.
When the re-engagement start condition of 00 is satisfied, step S300 is denied (NO). And step S4
The determination at 00 is affirmative (YES), so at step S600, the control DUTY is set so that the main clutch pressure is increased to engage the clutch LC, and re-engagement control is executed. At this time, steps S100 and S30
If the determinations of 0 and S500 are all negative (NO), the process of the pseudo neutral control routine is terminated without executing the process.

Next, the prospective control, which is a characteristic part of this embodiment, will be described in detail with reference to the flowcharts of FIGS. 6 to 12. In the present embodiment, even if the actual vehicle speed is not "0 km / h", the engagement state of the clutch LC is slip-engaged within a predetermined period in which the actual vehicle speed is "0 km / h". By controlling the value to the value just before the occurrence, the torque loss is prevented. First, as preconditions for the present embodiment, the vehicle speed “0 km / h” estimation of the present embodiment, which is one of the conditions for executing the prospective control, and the learning process executed during the steady control will be described.

The flow chart of FIG. 12 is a process relating to the vehicle speed "0 km / h" estimation of the present embodiment, which is a program started every predetermined period Δt. In this program, the turbine rotation speed Nt is detected as a substitute for the vehicle speed. This is because in the prospective control, the engagement state of the clutch LC is controlled so that slip does not occur, and therefore the turbine rotation speed Nt may be used as a substitute for the vehicle speed. Of course, the reduction rotation speed No may be used, or a vehicle speed sensor (not shown) may be used.

First, in step S800, it is determined whether the turbine rotation speed Nt (i) is higher than a predetermined rotation speed CNT. The predetermined rotation speed CNT is a value immediately before the turbine rotation speed sensor 28 cannot accurately detect the rotation speed. That is, the turbine rotation speed NT
When (i) is smaller than the predetermined rotation speed CNT, the accuracy of the sensor output is lowered, so that the vehicle speed cannot be accurately detected. Therefore, the turbine rotation speed N
When t is greater than the predetermined rotation speed CNT, the process proceeds to steps S801 to S803, and the vehicle speed is “0 km /
The time T (i) that is h ″ is calculated.

Specifically, in step S701, the rotational speed deviation ΔNt (i) is calculated by taking the deviation between the present turbine rotational speed Nt (i) and the previous turbine rotational speed Nt (i-1). To do. And step S80
2 as the deceleration degree A, the rotation speed deviation ΔNt (i)
Is divided by the period Δt which is the calculation cycle of this program. In step S803, the current turbine rotation speed Nt (i) is divided by the deceleration degree A so that the vehicle speed becomes "0 km /
The time T (i) until the time becomes "h" is updated and this routine is terminated. The process of updating the time T (i) is repeatedly executed until the determination in step S800 is negative (NO).

When the turbine rotation speed Nt is accurately smaller than the range by the turbine rotation speed sensor 28 in the determination of step S800, that is, when this determination is negative (NO), the process proceeds to step S804. In step S804, the determination in step S800 is negative (N
It is determined whether or not the time T (i) has elapsed since the time (O).
If the time T (i) has not elapsed, the routine is terminated. If it is determined that the time T (i) has elapsed, the routine proceeds to step S705, where the vehicle speed is "0 km / h" and the routine is terminated.

Next, using the flowchart of FIG.
The learning process of this embodiment will be described. This learning routine is a program for learning the average control duty value of the main clutch pressure in the steady control described above. In the steady control, the control DUTY is set so that the engagement state of the clutch LC becomes the pseudo neutral state. In the pseudo neutral state, the turbine shaft 14 is rotated by the engagement of the clutch LC, thereby suppressing the generation of the drag torque to the crankshaft 13 via the torque converter 12, and the clutch LC.
The main clutch pressure for the clutch LC is controlled in consideration of suppressing the response delay at the time of re-engagement by setting the piston stroke of 0 to 0. Therefore, the engagement start state of the clutch LC can be obtained by obtaining the average value of the control DUTY value with respect to the main clutch pressure in the steady control. Therefore, the engagement characteristic of the main clutch pressure can be known from the main clutch pressure for complete engagement and the main clutch pressure in the engagement start state. Then, since the engagement characteristic can be known, the control DUTY value of the main clutch pressure which is brought into the engagement state immediately before the slip engagement occurs can be estimated by obtaining the average control DUTY value during the steady control.

As described above, in order to obtain the control duty value of the main clutch pressure immediately before the slipping engagement occurs,
The learning process shown in 1 is executed. First, step S700
At, it is determined whether steady control is being executed. When the steady control is not executed, the determination in step S700 is negative (NO), and the present routine is ended as it is. On the other hand, if the steady control is being executed, step S70.
The determination of 0 is affirmative (YES) and proceeds to step S701. In step S701, based on the control DUTY value Pcl (n) of the main clutch pressure controlled during the steady control and the average value avPcl (n-1) of the control DUTY values obtained by the previous smoothing processing, The average value avPcl (n) of the current control DUTY values is calculated by a mathematical expression.

SmPcl (n) = {(1-B) / C} * avPcl (n-1) + B / C * Pcl (n) (1) In the above equation, B is a predetermined constant smaller than 1, C Is a predetermined constant, and this control D
The average value avPcl (n) of UTY values is calculated. The method of calculating the average value avPcl (n) is not limited to this, and the average value smPcl of the control DUTY values may be obtained by dividing the control DUTY value Pcl of a predetermined number of data by the number of predetermined data. . Thus average control DUT
If avPcl (n) of Y value is calculated, step S70
Go to 2. In step S702, it is determined whether or not a predetermined period TM3 has elapsed since the steady control was started. Here, the predetermined period TM3 is a value for determining whether the average value avPcl (n) obtained by the smoothing process is calculated based on the predetermined number of data. Then, when the predetermined period TM3 has not elapsed, the determination in step S702 is negative (NO), and the present routine ends as it is.

On the other hand, when the predetermined period TM3 has elapsed since the steady control was started, the determination at step S702 is affirmative (YES), and the routine proceeds to step S703. In step S703, a flag F indicating that learning is completed
Enter 1 in std. That is, when the average value avPcl (n) is a highly reliable learning value after the elapse of the predetermined period TM3, the learning value is learned in order to be reflected in the main clutch pressure control in the prospective control. The completion flag Fstd is set. As described above, when 1 is input to the learning completion flag Fstd, this routine ends.

Next, the prospective control of this embodiment will be described in detail with reference to the flowchart shown in FIG. First, in step S210, it is determined whether the predetermined period TM1 has elapsed. The predetermined period TM2 is a period from when the execution condition of the predictive control is satisfied to when the predictive control ends, and is a predetermined period in which the actual vehicle speed is always “0 km / h” as described above. . In this embodiment, for example, 2 seconds is set as the predetermined period. If it is determined in step S210 that the predetermined period TM1 has not elapsed since the prospective control was started,
The determination in step S210 is negative (NO), and the process proceeds to step S220. In step S220, a flag Ffst for determining whether the initial setting of the prospective control is completed.
It is determined whether 1 is 1.

If the initial setting is not completed, the flag Ffst1 is 0, so the determination in step S220 is negative, and the process proceeds to the initial setting process in step S230. The initialization process is executed by calling the subroutine shown in FIG. When the initialization routine of FIG. 7 is started, first, in step S231, it is determined whether or not a flag Fstd indicating learning completion, which will be described later, is 1. Here, when the flag Fstd is 1, the determination in step S231 is affirmative (YES), and the process proceeds to step S232. In step S232, the average value avPcl of the control DUTY values calculated by learning is multiplied by a predetermined coefficient COEF1 determined by the engagement characteristic of the clutch LC. This value is a control DUT for setting the engagement state of the clutch LC to the engagement region immediately before the slip engagement occurs.
Y value. Therefore, the predetermined DUTY value CPcl1 is subtracted in order to give a margin to this value so that sliding engagement does not occur, and the initial control DUTY value Pcl is set. Then, the process proceeds to step S235.

In the control DUTY based on the learning process set in step S232, step S2 described later is executed.
Compared with the control duty set in advance at 33, it is possible to accurately control the clutch LC to the engagement state immediately before the slip engagement occurs in response to the change over time and the individual difference. The predetermined DUTY value CPcl1 is equal to the control DUTY.
Even if the hydraulic pressure of the hydraulic pump 18 becomes unstable when the value Pcl is set, it is a value for providing a margin so that sliding engagement does not occur.

On the other hand, in step S231, the flag Fs
If it is determined that td is not 1, the determination in step S231 is negative (NO), and the process proceeds to step S233.
In step S233, since learning has not been completed, a predetermined value COEF2 set in advance is set as the control DUTY value. As a result, the clutch LC can be controlled in the engaged state immediately before the slip engagement occurs. Then, the process proceeds to step S235, and the increase degree ΔPcl of the control DUTY value is set in order to gradually reduce the pressure for engaging the clutch LC. This degree of increase ΔPc
1 is the clutch LC when the predetermined period TM2 has elapsed.
The engagement state of is set to a value immediately before the occurrence of sliding engagement. Then, assuming that the initial setting of the control duty value of the main clutch pressure is completed in step S236,
The initial setting flag Ffst1 is set to 1, and the routine proceeds to step S240 of FIG. 6 which is the main routine.

In step S240 of FIG. 6, the subroutine of FIG. 8 is activated to carry out the initial setting of the hill hold pressure. When this routine is started, step S2
At 41, a predetermined control DUTY value Phhmin is set as the control DUTY value Phh of the hill hold pressure. The control DUTY value Phmin is set to, for example, 0% DUTY so that the hydraulic pressure for controlling the engagement state of the brakes 2 & 4B is maximized. Then, in step S242, the decrease degree ΔPhh of the control DUTY value is set so that the hill hold pressure is gradually increased,
It proceeds to step S243. In step S243, it is determined that the initialization of the control duty value of the hill hold pressure is completed, the initialization flag Ffst2 is set to 1, this routine is completed, and then the main routine of FIG. 6 is completed.

When the initial settings for the main clutch pressure and the hill hold pressure are completed as described above,
Since the initial setting flags Ffst1 and Ffst2 are set to 1, the determination in step S220 of the main routine in FIG. 6 is affirmative (YES), and the process proceeds to steps S250 and S260. First, in step S250, the subroutine shown in FIG. 9 is started in order to set the control DUTY value for the main clutch pressure. Figure 9
In step S251, the control duty DUTY value Pcl (n-1) of the previous main clutch pressure is read. Then, the degree of increase ΔP of the main clutch pressure control DUTY value set in step S235 of the flowchart of FIG.
Cl is added to the previous control DUTY value Pcl (n-1) to set the current control DUTY value Pcl (n-1). In this way, the control D for the main clutch pressure
When the UTY value Pcl (n) is set, the process returns to the main routine of FIG. 6 and the process of step S260 is executed.

In step S260, the subroutine of FIG. 10 is started and executed as hill hold pressure control. When this subroutine is activated, first, in step S261, the control DUT for the previous hill hold pressure is performed.
The Y value Phh (n-1) is read and the process proceeds to step S262. In step S262, it is determined whether a predetermined period TM2 has elapsed since the initialization of the control duty value Phh for the hill hold pressure was completed. The predetermined period TM2 is
It is a value set to quickly fill the brakes 2 & 4B with oil. During this period TM2, the determination in step S262 is negative (NO), and step S26
Go to 3. In step S263, the previous control DUTY value Phh (n-1) is set as the control DUTY value Phh (n) for rapid oil filling, and the control DUTY value Phhmin set by the initial setting is set. That is, as the control DUTY value Phh (n), for example, 0
When% is set, the hydraulic control valve is fully opened to perform rapid oil filling, and this routine is ended.

On the other hand, after the initial setting of the control duty value Phh is completed, a predetermined period TM2 for rapidly filling the oil is set.
If is passed, the determination in step S262 is affirmative (YE
S) and the process proceeds to step S264. Step S264
Then, it is determined whether or not a flag Ffst3 described later is 1. Since the flag Ffst3 is initially set to 0, the determination in step S264 is negative (N
O) and the process proceeds to step S265. Control DUT to be initially set after the completion of the predetermined period TM2 for rapid filling
The Y value Phh (n) is a predetermined DUTY value CP such that torque shock is not generated by the engagement of the brakes 2 & 4B.
hh is set. When this setting is completed, the process proceeds to step S266, the flag Ffst3 indicating that this setting is completed is set to 1, and this routine is completed.

Since the flag Ffst3 is set to 1, the determination in step S264 is always affirmative (YES) after this process, and the flow advances to step S267. In step S267, from the control DUTY value Phh (n-1) for the previously set hill hold pressure, the control D set in step S242 of the flowchart of FIG. 8 is set.
This time control D is performed by subtracting the decrease degree ΔPhh of the UTY value.
Set the UTY value Phh (n). Then, when this process ends, the main routine of FIG. 6 also ends.

As described above, in the present embodiment, even if the actual vehicle speed is not "0 km / h", the clutch LC
It is possible to prevent the torque loss from occurring by controlling so that the sliding engagement does not occur in the engagement state of 1. Next, the control operation of the present embodiment will be described using the time chart of FIG.

First, the timing at which the vehicle speed is estimated or detected to be "0 km / h" is time t1. At time t1, the prospective control execution condition is satisfied, and the control DUTY value Pcl for the main clutch pressure is set to the predetermined DU.
By setting TY large, the main clutch pressure decreases by a predetermined pressure. Then, the control DUTY value for the main clutch pressure is increased by ΔPcl so that the main clutch pressure is reduced by a constant pressure every calculation cycle of the control DUTY value Pcl for the main clutch pressure. In FIG. 13, the control DUT for the main clutch pressure is performed every predetermined period.
The Y value Pcl is set to a large value. Regardless of which setting method is used, the main clutch pressure is gradually increased until the time t3 when the predetermined period TM1 which is the execution period of the prospective control elapses so that the clutch LC becomes the value immediately before the slip engagement occurs. Is decompressed. In the present embodiment, the value immediately before the occurrence of the sliding engagement is obtained from the learning value of the average control DUTY value during the steady control.

On the other hand, for the control DUTY value Phh for the hill hold pressure shown in the time chart of FIG. 13, a predetermined DUTY value Phhmin is set when the prospective control is started, and the rapid filling control is started and continues until time t2. Then, at time t2, the control DUTY value Phh is set to the predetermined DUTY value CPhh in order to temporarily reduce the hill hold pressure. After that, the main clutch pressure is increased by a predetermined pressure until the transition control start time at time t3.
The control DUTY value Phh is set smaller by the degree of decrease ΔPhh. In the time chart of FIG. 13, time t3
When the steady control is started at, the degree of decrease ΔP thereafter
The control DUTY value Phh is decreased with a degree of decrease larger than hh. Then, finally, the brakes 2 & 4B are completely engaged.

The control duty value Pcl for the main clutch pressure may be set as shown in FIG. In this figure, t1 to t4 are times t1 to t1 in FIG.
matches t4. In the upper diagram of FIG. 14, the method of setting the control DUTY value Pcl with respect to the main clutch pressure is to set the control DUTY to 100% from the time t1 to the time t2 to close the hydraulic control valve of the clutch LC. Do not apply clutch pressure. Then, time t2
The control DUTY value Pcl is set to a value that does not cause slipping engagement as the engagement state of the clutch LC. And
After that, the damping degree ΔPcl of the control DUTY value is added so that the main clutch pressure gradually decreases in each calculation cycle of the control DUTY value Pcl, and the hydraulic control valve is controlled to gradually close.

Similarly, in the lower diagram of FIG.
The control DUTY value Pcl may be set so that the main clutch pressure is gradually attenuated in a cycle longer than the calculation cycle. In any of the above main clutch pressure control methods, it is needless to say that control is performed so that slip engagement does not occur during execution of predictive control.

On the other hand, in addition to these main clutch pressure control methods, the hill hold pressure control methods shown in FIG. 15 may be used in combination. Also in this figure, times t1 to t4 coincide with times t1 to t4 in FIG. In the upper diagram of FIG. 15, in the method of setting the control DUTY value Phh for the hydraulic control valve for controlling the hill hold pressure, when rapid filling for the brakes 2 & 4B is performed from time t1 to time t2, pressure t Depressurize once. This will brake 2 &
The torque shock when 4B is engaged is reduced. After that, the hill hold pressure is increased at a predetermined cycle until the brakes 2 & 4B are completely engaged.

Further, in the middle diagram of FIG. 15, the hill hold pressure is increased by a predetermined pressure without executing the rapid filling. And
After that, the degree of decrease ΔPh of the control duty value Phh is increased so that the hill hold pressure Phh gradually increases at every predetermined cycle.
Set h. When the transient control is started at time t3, the degree of decrease Δ set at time t2 from time t2.
The control DUTY value Phh is decreased with a degree of decrease larger than Phh, and the control DUTY value Phh is set so that the brakes 2 & 4B are finally engaged. In the lower diagram of FIG.
At the start time t1 of the predictive control, the hill hold pressure is increased by a predetermined pressure as in the middle figure, and then the decrease degree ΔP of the control DUTY value Pcl is increased so that the pressure increases at a constant increase rate.
Set cl.

As described above, by performing the main clutch pressure control of FIG. 14 and the hill hold pressure control of FIG. 15 in combination, the hydraulic pressure of the hydraulic pump 18 is stabilized by the time the transient control starts at time t3. You can Therefore, stable control can be performed when the transient control is executed.

In the present embodiment, in order to learn the value immediately before the slipping engagement occurs, learning is performed based on the control duty value Pcl of the main clutch pressure during execution of steady control, but instead of this, Then, when the turbine rotation speed Nt changes, it is advisable to learn the control value for controlling the clutch LC into the engagement state immediately before the slip engagement occurs on the side that prevents the slip engagement.

Further, in the present embodiment, the vehicle speed of the vehicle is calculated, but instead of this, the start determination of the prospective control may be performed based on the output of a vehicle speed sensor (not shown). In this case, the output value of the vehicle speed sensor is "0 km /
Since a phenomenon such as sticking of output values occurs near h ”,
The reliability is low near "0 km / h". Therefore, if the vehicle speed sensor output is present within the predetermined period TM1 even if the condition for starting the predictive control is satisfied, the start determination of the predictive control may be executed again.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of the present invention.

FIG. 2 is a schematic view showing an automatic transmission mechanism of the present invention.

FIG. 3 is a map showing a shift pattern of the present invention.

FIG. 4 is a time chart showing pseudo neutral control according to the present embodiment.

FIG. 5 is a main program of the pseudo neutral control of the present invention.

FIG. 6 is a flowchart showing a main program for predictive control according to the present invention.

FIG. 7 is a flowchart showing an initial setting of main clutch pressure control in the present embodiment.

FIG. 8 is a flowchart showing initial setting of hill hold pressure control in the present embodiment.

FIG. 9 is a flowchart showing main clutch pressure control in the present embodiment.

FIG. 10 is a flowchart showing hill hold pressure control in the present embodiment.

FIG. 11 is a flowchart showing a learning program for an average main clutch pressure control DUTY value during steady control in the present embodiment.

FIG. 12 is a flowchart showing estimation of vehicle speed “0 km / h” in the present embodiment.

FIG. 13 is a time chart showing a main clutch pressure control DUTY value and a hill hold pressure control DUTY value in the present embodiment.

FIG. 14 is a time chart showing a method for setting a main clutch pressure control DUTY value as another embodiment.

FIG. 15 is a time chart showing a method for setting a hill hold pressure control DUTY value as another embodiment.

[Explanation of symbols]

11 ... Automatic transmission, 12 ... Torque converter, 16 ... Lockup clutch, 17 ... Hydraulic control circuit, 18 ... Hydraulic pump, 19 ... Line pressure control circuit, 20 ... Automatic shift control circuit, 21 ... Lockup control circuit, 26 ... Manual switching valve, 27 ... Engine speed sensor, 30 ... AT-ECU, LC, HC, RC ... Clutch (friction engagement element), 2 & 4B, L & RB ... Brake (friction engagement element).

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 3J552 MA02 MA12 PA47 PA48 RB07                       RC07 RC12 SA07 VA32W                       VB01W VC03W VD11W

Claims (6)

[Claims] 1. A forward control means, a transient control means, and a steady state control means for forming a pseudo-neutral state when the forward drive range is selected, the vehicle is at a standstill, and the engine is in an idle operation state. A control device for an automatic transmission, comprising: a control means; a forward clutch that is engaged when a forward drive range is selected; and a first hydraulic control for engaging the forward clutch by supplying hydraulic pressure. A valve, a prospective control start determination means for determining whether or not to perform a prospective control for forming a pseudo neutral state, and a hydraulic pressure control valve that adjusts the hydraulic control valve to control the hydraulic pressure supplied to the forward clutch. 1 hydraulic control valve control means, and the predictive control is performed for a predetermined period after the predictive control start determining means determines to start predictive control. The first hydraulic control unit controls the first hydraulic control valve control unit so that the forward clutch is completely engaged by the first hydraulic control valve control unit so that the forward clutch is engaged immediately before slipping engagement. A means for adjusting a valve, wherein the transient control means changes the engagement state of the forward clutch immediately before the slip engagement occurs to the slip engagement state immediately before the advance clutch is released. It is a means for adjusting a first hydraulic control valve, wherein the steady control means maintains the sliding engagement state immediately before the forward clutch is released from the forward clutch to form the pseudo-neutral state. A control device for an automatic transmission, which is means for adjusting the first hydraulic control valve. 2. A brake state detecting means for detecting a state of a brake of a vehicle, a throttle opening detecting means for detecting an opening degree of a throttle valve arranged in an intake passage of an internal combustion engine, and a vehicle speed in a stopped state. A stop state detecting means for detecting or estimating that there is, and the predictive control start determining means detects a state in which the brake of the vehicle detected by the brake state detecting means is depressed, and the throttle opening detecting means. The start of the predictive control is determined based on one or more of the following conditions: the throttle opening is in the fully closed position, or the vehicle state detected or estimated by the stop state detecting means is a stop state. The control device for an automatic transmission according to claim 1, wherein: 3. A learning means for learning a control value for adjusting the first hydraulic control valve for forming the pseudo-neutral state by the steady control means, wherein the forward clutch is in slip engagement. The control value for adjusting the first hydraulic control valve by the first hydraulic control valve control means so as to be in the engagement state immediately before the occurrence is set based on the learning value learned by the learning means. The control device for an automatic transmission according to claim 1, wherein the control device is an automatic transmission. 4. A reverse drive brake for preventing the output shaft of the automatic transmission from rotating in the reverse drive direction of the vehicle; a second hydraulic control valve for adjusting engagement of the reverse drive brake; A second hydraulic pressure control valve control means for controlling the hydraulic pressure supplied to the reverse brake by adjusting the second hydraulic pressure control valve, wherein the prediction control start determination means is a start condition of the prediction control means. The judgment control means engages the second hydraulic pressure control valve by the second hydraulic pressure control valve control means when the determination is made. Automatic transmission control device. 5. A turbine shaft for transmitting rotation from a crankshaft of an internal combustion engine to an automatic transmission via a torque converter, and turbine rotation speed detection means for detecting a rotation speed of the turbine shaft, wherein the predictive control is provided. When the turbine rotation speed detected by the turbine rotation speed detection means changes during the prospective control by the means, the first clutch is brought into an engaged state immediately before the slipping engagement occurs. The control value for adjusting the first hydraulic control valve by the hydraulic control valve control means is learned by a side that prevents slipping engagement from occurring in the forward clutch. The control device for the automatic transmission according to item 3. 6. A vehicle speed sensor for detecting the speed of a vehicle, and a vehicle speed sensor output detecting means for detecting the output of the vehicle speed sensor, wherein the predictive control start determining means determines that the predictive control is started. When it is detected that the vehicle speed is generated by the output of the vehicle speed sensor within the predetermined period, the predictive control by the predictive control means is ended, and the predictive control start determination is executed again. The control device for an automatic transmission according to any one of claims 1 to 5.