JP2009275812A - Automatic transmission controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a shock from occurring when restoring a transmission gear mechanism of an automatic transmission from a quasi-neutral state (a state of decreasing an engaging force of a clutch on an engaging side) to a normal state. <P>SOLUTION: When a releasing condition of the quasi-neutral state has been established during quasi-neutral control for making the transmission gear mechanism into the quasi-neutral state, restoring control is performed to restore the transmission gear mechanism from the quasi-neutral state to the normal state. In this restoring control, an oil pressure command value of the clutch on the engaging side is corrected depending on a revolution speed difference between an input shaft revolution speed Nt of the transmission gear mechanism and a target synchronous revolution speed (a revolution speed obtained by multiplying a first-stage transmission ratio by an output shaft revolution speed No of the transmission gear mechanism). As a result, even if a revolution speed difference is small between the input shaft revolution speed Nt of the transmission gear mechanism and the target synchronous revolution speed during quasi-neutral control, the input shaft revolution speed Nt of the transmission gear mechanism is allowed to gently decease during restoring control, thereby moderately proceeding to the target synchronous revolution speed. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an automatic transmission control device having a function of controlling a speed change mechanism to a pseudo neutral state when a predetermined condition is satisfied.

  An automatic transmission for an automobile transmits a driving force of an internal combustion engine to an input shaft of a transmission mechanism through a torque converter, shifts the transmission by the transmission mechanism and transmits it to an output shaft, and rotationally drives a drive wheel. Yes. In general, a speed change mechanism has a plurality of gears arranged 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. Are provided with friction engagement elements such as clutches and brakes, and by individually controlling the hydraulic pressure applied to each friction engagement element in response to a shift request, engagement and release of each friction engagement element are selectively performed. By switching, the power transmission path between the input and output shafts is switched to switch the gear position (speed ratio).

  In such an automatic transmission control device, as described in Patent Document 1 (Japanese Patent Application Laid-Open No. 2003-202076), a D lever (drive range) is used with a shift lever for the purpose of improving the fuel consumption of the internal combustion engine. The engagement force of the engagement side frictional engagement element to be engaged when traveling in the travel range when the vehicle is in a stopped state and the internal combustion engine is in the idle operation state with the travel range such as There is a type in which pseudo neutral control is performed to control the hydraulic pressure command value of the engagement side frictional engagement element so that the transmission mechanism is lowered and maintained in a pseudo neutral state (hereinafter referred to as “pseudo neutral state”). .

  In such a system that performs pseudo-neutral control, even when the travel range is selected, when the speed change mechanism is set to the pseudo-neutral state, torque is not transmitted to the wheels so much that the vehicle is stopped on the uphill road. Immediately after releasing the brake to start the vehicle, the vehicle may move backward.

As a countermeasure, as described in Patent Document 2 (Japanese Patent Application Laid-Open No. 2004-225797), the slope of the uphill road where the vehicle is stopped is detected during pseudo neutral control, and the slope of the uphill road is large. The torque transmitted to the wheel is increased by controlling the hydraulic pressure command value of the engagement side frictional engagement element so as to increase the difference (slip amount) between the input shaft rotation speed and the output shaft rotation speed of the torque converter. There is something to let you do.
Japanese Patent Laid-Open No. 2003-202076 (see page 3) JP 2004-225797 A (see page 2 etc.)

  Incidentally, during the pseudo neutral control, the present inventor first performs the return control for returning the transmission mechanism from the pseudo neutral state to the normal state by, for example, depressing the accelerator pedal and establishing the pseudo neutral state release condition. The pressure increase control for increasing the hydraulic pressure command value of the engagement side frictional engagement element with a predetermined constant gradient is executed, and after detecting the change in the input shaft rotational speed of the speed change mechanism due to the pressure increase control, the input of the speed change mechanism The hydraulic pressure command value of the engagement side frictional engagement element is feedback controlled so that the change rate (decreasing gradient) of the shaft rotation speed matches the target change rate, and the progress rate of the return control reaches a predetermined value during this feedback control. When the target change rate is moderated, the input shaft rotational speed of the transmission mechanism is changed to the target synchronous rotational speed (the rotational speed obtained by multiplying the output shaft rotational speed of the transmission mechanism by the first gear ratio) While studying a system for slowly soft landing feedback control to converge towards, new challenges such as the following were found in the research process.

  As in the technique of Patent Document 2, the difference (slip amount) between the input shaft rotational speed and the output shaft rotational speed of the torque converter is increased as the slope of the uphill road where the vehicle is stopped is increased during pseudo neutral control. When the hydraulic pressure command value of the engagement side frictional engagement element is controlled so as to increase, the difference between the input shaft rotation speed of the transmission mechanism and the target synchronous rotation speed is reduced, so the transmission mechanism is returned from the pseudo-neutral state to the normal state. When the pressure increase control and the feedback control are executed, the time until the input shaft rotation speed of the transmission mechanism decreases to the vicinity of the target synchronous rotation speed is shortened. For this reason, before the effect of the feedback control is obtained, the input shaft rotational speed of the transmission mechanism reaches the target synchronous rotational speed, and the input shaft rotational speed of the transmission mechanism can be gradually converged to the target synchronous rotational speed. There is a possibility that a shock will occur.

  The present invention has been made in view of such circumstances. Accordingly, an object of the present invention is to prevent a shock from occurring when the transmission mechanism is returned from the pseudo-neutral state to the normal state. An object of the present invention is to provide a control device for an automatic transmission.

  To achieve the above object, the invention according to claim 1 is applied to a vehicle that transmits the power of an internal combustion engine to a wheel side via a torque converter and a speed change mechanism, and a plurality of friction engagements provided in the speed change mechanism. Hydraulic control means is provided with hydraulic control means for selectively switching engagement and disengagement of each friction engagement element by individually controlling the hydraulic pressure applied to the elements to switch the gear stage of the transmission mechanism. When the vehicle is in a stopped state and the internal combustion engine is in an idling operation state, the engagement-side frictional engagement element that is engaged when the vehicle travels in the travel range reduces the engagement force of the engagement-side friction engagement element. In a control device for an automatic transmission that controls a hydraulic pressure command value of an engagement side frictional engagement element so as to maintain a mechanism in a pseudo neutral state (hereinafter referred to as a “pseudo neutral state”), the hydraulic control means includes a pseudo Rotation speed obtained by multiplying the input shaft rotational speed of the speed change mechanism and the output shaft rotational speed of the speed change mechanism by the speed ratio of the gear stage at the start of the vehicle (for example, the speed ratio of the first speed) when the release condition of the total state is satisfied The hydraulic pressure command value of the engagement side frictional engagement element is changed in accordance with the difference from the following (hereinafter referred to as “target synchronous rotation speed”).

  In this configuration, even if the difference between the input shaft rotational speed of the transmission mechanism and the target synchronous rotational speed is small during pseudo neutral control for controlling the transmission mechanism to the pseudo neutral state, the condition for canceling the pseudo neutral state is satisfied, and When the mechanism is returned from the pseudo-neutral state to the normal state, the hydraulic pressure command value of the engagement side frictional engagement element is changed in accordance with the difference between the input shaft rotational speed of the speed change mechanism and the target synchronous rotational speed. By controlling the hydraulic pressure of the engagement side frictional engagement element so as to gently decrease the input shaft rotation speed of the mechanism, the input shaft rotation speed of the speed change mechanism can be gradually converged to the target synchronous rotation speed. Occurrence can be prevented in advance.

  The present invention executes pressure increase control for increasing the hydraulic pressure command value of the engagement side frictional engagement element with a predetermined gradient when the condition for canceling the pseudo-neutral state is satisfied. When detecting a change in the input shaft rotation speed of the speed change mechanism by the control and applying it to a system that feedback-controls the hydraulic pressure command value of the engagement side frictional engagement element so that the rate of change of the input shaft rotation speed matches the target value good. In this way, when the condition for canceling the pseudo-neutral state is established and the transmission mechanism is returned from the pseudo-neutral state to the normal state, the input shaft rotational speed of the transmission mechanism is reduced before the effect of feedback control is obtained. Even when the vicinity of the target synchronous rotational speed is reached, by changing the hydraulic pressure command value of the engagement side frictional engagement element according to the difference between the input shaft rotational speed of the transmission mechanism and the target synchronous rotational speed, the speed change mechanism The input shaft rotation speed can be gradually converged to the target synchronous rotation speed.

  Further, as in claim 3, when a change in the input shaft rotational speed of the speed change mechanism by the pressure increase control is detected and the difference between the input shaft rotational speed of the speed change mechanism and the target synchronous rotational speed is equal to or less than a predetermined value, Feedback control of the hydraulic pressure command value of the engagement side frictional engagement element may be prohibited by the feedback control prohibiting means. That is, when the difference between the input shaft rotational speed of the speed change mechanism and the target synchronous rotational speed is equal to or smaller than a predetermined value, the input shaft rotational speed of the speed change mechanism is already near the target synchronous rotational speed. It is determined that there is no need to perform feedback control of the hydraulic command value of the element, and feedback control is prohibited. Thereby, it is possible to simplify the control when the transmission mechanism is returned from the pseudo-neutral state to the normal state.

  Further, as in claim 4, when the feedback control of the hydraulic pressure command value of the engagement side frictional engagement element is prohibited, the hydraulic pressure command value of the engagement side frictional engagement element is set to the value at the end of the pressure increase control. It is better to maintain the hydraulic pressure command value. In other words, since the input shaft rotation speed of the transmission mechanism is already near the target synchronous rotation speed, if the feedback control of the hydraulic pressure command value of the engagement side frictional engagement element is prohibited, the hydraulic pressure of the engagement side frictional engagement element is By maintaining the command value at the hydraulic pressure command value at the end of the pressure increase control, the input shaft rotation speed of the speed change mechanism can be gradually converged to the target synchronous rotation speed.

Hereinafter, an embodiment embodying the best mode for carrying out the present invention will be described.
First, a schematic configuration of the automatic transmission 11 will be described with reference to FIGS. 1 and 2.
As shown in FIG. 2, an input shaft 13 of a torque converter 12 is connected to an output shaft of an engine (not shown), and a hydraulically driven transmission gear mechanism 15 (speed change) is connected to the output shaft 14 of the torque converter 12. Mechanism). Inside the torque converter 12, a pump impeller 31 and a turbine runner 32 constituting a fluid coupling are provided to face each other, and a stator 33 for rectifying the flow of oil is provided between the pump impeller 31 and the turbine runner 32. It has been. The pump impeller 31 is connected to the input shaft 13 of the torque converter 12, and the turbine runner 32 is connected to the output shaft 14 of the torque converter 12.

  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 engine output torque is transmitted to the transmission gear mechanism 15 via the torque converter 12, and is shifted by a plurality of gears (front planetary gear 23, rear planetary gear 22 and the like) of the transmission gear mechanism 15 to drive the vehicle drive wheels (front wheels or Is transmitted to the rear wheels. The transmission gear mechanism 15 is provided with a plurality of clutches RC, HC, LC and brakes B0, B1, which are friction engagement elements for switching a plurality of shift stages, and a low one-way clutch 34. As shown in FIG. 3, the gear ratio is switched by switching the engagement / release of each of the clutches RC, HC, LC and the brakes B0, B1 by hydraulic pressure and switching the combination of gears for transmitting power. Yes.

  FIG. 3 shows a combination of engagement of the clutches RC, HC, LC and brakes B0, B1 of the 4-speed automatic transmission. The circles are held in the engaged state (torque transmission state) at the gear stage. The clutch and brake are shown, and the unmarked state shows the released state. The symbol ◎ indicates that the engagement is performed only at the time of the corresponding drive, and the symbol Δ indicates that the engagement is performed only when the vehicle is started and the vehicle speed exceeds a predetermined value.

  For example, in the D range (drive range) saccel stepping-on state, the vehicle is upshifted to the first speed, the second speed, the third speed, and the fourth speed as the vehicle speed increases. In the shift from the first speed to the second speed, B1 is released from the engaged state of LC and B1, and B0 is newly engaged. In the shift from the second speed to the third speed, B0 is released from the engaged state of LC and B0, and HC is newly engaged. In the shift from the 3rd speed to the 4th speed, the LC is released from the engaged state of the HC and the LC, and B0 is newly engaged.

  As shown in FIG. 1, the transmission gear mechanism 15 is provided with a hydraulic pump 18 driven by engine power, and a hydraulic control circuit 17 is provided in an oil pan (not shown) for storing hydraulic oil (oil). Is provided. The hydraulic control circuit 17 is composed of a line pressure control circuit 19, an automatic transmission control circuit 20, a lockup control circuit 21, a manual switching valve 26, and the like. The hydraulic oil pumped up from the oil pan by the hydraulic pump 18 is controlled by the line pressure. This is supplied to the automatic transmission control circuit 20 and the lockup control circuit 21 via the circuit 19. The line pressure control circuit 19 is provided with a hydraulic pressure control valve (not shown) for controlling the hydraulic pressure from the hydraulic pump 18 to a predetermined line pressure. The automatic transmission control circuit 20 has a transmission gear mechanism. A plurality of shift hydraulic control valves (not shown) for controlling the hydraulic pressure supplied to the 15 clutches RC, HC, LC and the brakes B0, B1 are provided. 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.

  A manual switching valve 26 that is switched in conjunction with the operation of the shift lever 25 is provided between the line pressure control circuit 19 and the automatic transmission control circuit 20. When the shift lever 25 is operated to the N range (neutral range) or the P range (parking range), even if the power supply to the hydraulic control valve of the automatic transmission control circuit 20 is stopped (OFF), The hydraulic pressure supplied to the transmission gear mechanism 15 by the manual switching valve 26 is switched so that the transmission gear mechanism 15 is in a neutral state.

  On the other hand, the engine is provided with an engine rotation speed sensor 27 that detects an engine rotation speed Ne (the rotation speed of the input shaft 13 of the torque converter 12). The transmission gear mechanism 15 has an input shaft rotation speed of the transmission gear mechanism 15. An input shaft rotational speed sensor 28 for detecting Nt (rotational speed of the output shaft 14 of the torque converter 12) and an output shaft rotational speed No of the transmission gear mechanism 15 (rotational speed of the output shaft 35 of the transmission gear mechanism 15) are detected. An output shaft rotation speed sensor 29 is provided.

  Output signals of these various sensors are input to an automatic transmission electronic control circuit (hereinafter referred to as “AT-ECU”) 30. The AT-ECU 30 is configured mainly by a microcomputer, and functions as hydraulic control means in the claims by executing each routine stored in a built-in ROM (storage medium), and is set in advance. Energizing each hydraulic control valve of the automatic transmission control circuit 20 according to the operating position of the shift lever 25 and the operating conditions (throttle opening, vehicle speed, etc.) so that the transmission of the transmission gear mechanism 15 is executed according to the transmission pattern. By controlling the hydraulic pressure applied to each clutch RC, HC, LC and each brake B0, B1 of the transmission gear mechanism 15, as shown in FIG. 3, each clutch RC, HC, LC and each brake B0. , B1 are switched to engage / release, and the gear ratio of the transmission gear mechanism 15 is switched by switching the combination of gears that transmit power.

  Further, the AT-ECU 30 executes a pseudo neutral control routine (not shown), and as shown in FIG. 4, the shift lever 25 causes the D range (drive range), 2 range (second range), L range (low range), etc. When the vehicle is stopped with the travel range selected, and the engine is in the idle operation state, the hydraulic command for the engagement clutch (for example, clutch LC) to be engaged when traveling in the travel range. By reducing the value to lower the hydraulic pressure of the engagement side clutch, the engagement force of the engagement side clutch is reduced to maintain the transmission gear mechanism 15 in a pseudo neutral state (hereinafter referred to as “pseudo neutral state”). Perform pseudo-neutral control.

  In such a system that performs pseudo-neutral control, even when the travel range is selected, when the transmission gear mechanism 15 is in the pseudo-neutral state, torque is not transmitted to the wheels so much that the vehicle is stopped on an uphill road. Immediately after releasing the brake to start from the state, the vehicle may move backward.

  As a countermeasure against this, as shown in FIGS. 5 and 6, the slope of the uphill road where the vehicle is stopped is detected during pseudo neutral control, and the higher the slope of the uphill road, the higher the input shaft rotation speed of the torque converter 12 becomes. By controlling the hydraulic pressure command value of the engagement side clutch so as to increase the slip amount which is the difference from the output shaft rotational speed (that is, the difference between the engine rotational speed Ne and the input shaft rotational speed Nt of the transmission gear mechanism 15). You may make it increase the torque transmitted to a wheel.

  Further, the AT-ECU 30 executes the routines shown in FIGS. 7 and 8 to be described later, and, as shown in FIG. 4, for example, the accelerator pedal is depressed during the pseudo neutral control, and the release condition for the pseudo neutral state is satisfied. When this is done, return control is performed to return the transmission gear mechanism 15 from the pseudo-neutral state to the normal state.

  In this return control, as shown in FIG. 4, first, at time t1 when the condition for canceling the pseudo-neutral state is satisfied, pressure increase control is executed to increase the hydraulic pressure command value of the engagement side clutch with a predetermined constant gradient. As a result, the hydraulic pressure of the engagement side clutch is increased and the engagement force of the engagement side clutch is increased, so that the input shaft rotation speed Nt of the transmission gear mechanism 15 starts to decrease.

  Thereafter, at the time t2 when the change in the input shaft rotational speed Nt of the transmission gear mechanism 15 due to the pressure increase control is detected, the change rate (decrease gradient) of the input shaft rotational speed Nt of the transmission gear mechanism 15 is made to coincide with the target change rate. F / B control (feedback control) for controlling the hydraulic pressure command value of the engagement side clutch is executed, and at the time t3 when the rate of progress of return control reaches a predetermined value during this F / B control, the target change rate The input shaft rotational speed Nt of the transmission gear mechanism 15 is multiplied by the target synchronous rotational speed (the output shaft rotational speed No of the transmission gear mechanism 15 is multiplied by the speed ratio of the first speed that is the gear stage at the start of the vehicle. The soft landing F / B control is performed to converge gently toward the rotation speed.

  Thereafter, at the time point t4 when the difference between the input shaft rotational speed Nt of the transmission gear mechanism 15 and the target synchronous rotational speed becomes equal to or smaller than the determination value and the first gear ratio is established, the hydraulic command value for the engaging clutch is maximized. End control for increasing the pressure to a high pressure is executed to increase the hydraulic pressure of the engagement side clutch to the maximum pressure, thereby completing the return control.

  By the way, as shown in FIG. 5, in pseudo neutral control, the difference between the input shaft rotational speed and the output shaft rotational speed of the torque converter 12 (that is, the engine rotational speed) is increased as the slope of the uphill road where the vehicle is stopped is larger. When the hydraulic pressure command value of the engagement side clutch is controlled so as to increase the slip amount, which is the difference between Ne and the input shaft rotation speed Nt of the transmission gear mechanism 15, the input shaft rotation speed Nt of the transmission gear mechanism 15 and the target synchronization are controlled. Since the difference with the rotational speed becomes small, when the pressure increase control and the F / B control are executed when the speed change gear mechanism 15 is returned from the pseudo neutral state to the normal state, the input shaft speed of the speed change gear mechanism 15 is increased. The time until Nt decreases to near the target synchronous rotation speed is shortened. Therefore, if nothing is done, the input shaft rotational speed Nt of the transmission gear mechanism 15 reaches the target synchronous rotational speed before the effect of the F / B control is obtained, and the input shaft rotational speed of the transmission gear mechanism 15 is reached. Nt cannot be gradually converged to the target synchronous rotation speed, and a shock may occur.

  As a countermeasure against this, in this embodiment, as shown in FIG. 6, when the return control for returning the transmission gear mechanism 15 from the pseudo-neutral state to the normal state is performed when the release condition for the pseudo-neutral state is established, Depending on the rotational speed difference between the input shaft rotational speed Nt of the gear mechanism 15 and the target synchronous rotational speed (the rotational speed obtained by multiplying the output shaft rotational speed No of the transmission gear mechanism 15 by the first gear ratio), Correct the hydraulic pressure command value. As a result, even if the rotational speed difference between the input shaft rotational speed Nt of the transmission gear mechanism 15 and the target synchronous rotational speed is small during pseudo neutral control, the input shaft rotational speed Nt of the transmission gear mechanism 15 is gradually reduced during the return control. By controlling the hydraulic pressure command value of the engagement side clutch so as to decrease the input shaft rotational speed, the input shaft rotational speed Nt of the transmission gear mechanism 15 can be gradually converged to the target synchronous rotational speed.

  The return control from the pseudo-neutral state described above is executed by the AT-ECU 30 according to the routines shown in FIGS. Hereinafter, the processing content of each of these routines will be described.

[Return control routine]
The return control routine shown in FIG. 7 is executed at predetermined intervals while the AT-ECU 30 is powered on. When this routine is started, first, in step 101, it is determined whether the condition for canceling the pseudo neutral state is satisfied, for example, whether the accelerator pedal is depressed during the pseudo neutral control, whether the brake operation is released. Judgment is based on whether or not.

  If it is determined in step 101 that the condition for canceling the pseudo-neutral state is not satisfied, the process proceeds to step 102 where the input shaft rotational speed Nt of the transmission gear mechanism 15 (that is, before the return control is started) and the target synchronization are performed. The rotational speed difference with the rotational speed (the rotational speed obtained by multiplying the output shaft rotational speed No of the transmission gear mechanism 15 by the speed ratio of the first speed, which is the shift stage when the vehicle starts) is calculated and stored in the memory.

Thereafter, when it is determined in step 101 that the condition for canceling the pseudo-neutral state is satisfied, the process proceeds to step 103, and the control stage flag FlagAN for determining the stage of return control is set to the initial value “0”. After resetting, the routine proceeds to step 104, where the engagement side clutch hydraulic pressure control routine of FIG. 8 is executed.
[Engagement side clutch hydraulic control routine]
The engagement side clutch hydraulic pressure control routine shown in FIG. 8 is a subroutine executed in step 104 of the return control routine of FIG. When this routine is started, first, in step 201, the current return control stage is determined depending on whether the value of the control stage flag FlagAN is 0 to 4.

  Since the control stage flag FlagAN is set to the initial value “0” at the time of starting the engagement side clutch hydraulic pressure control, the process proceeds to step 202 to increase the hydraulic pressure command value of the engagement side clutch at a predetermined constant gradient. Execute pressure increase control. As a result, the hydraulic pressure of the engagement side clutch is increased and the engagement force of the engagement side clutch is increased, so that the input shaft rotation speed Nt of the transmission gear mechanism 15 starts to decrease.

  Thereafter, the routine proceeds to step 203, where the rotational speed between the input shaft rotational speed Nt of the transmission gear mechanism 15 and the target synchronous rotational speed (the rotational speed obtained by multiplying the output shaft rotational speed No of the transmission gear mechanism 15 by the first gear ratio). The hydraulic pressure command value of the engagement side clutch is corrected according to the difference. In this case, a reduction correction value corresponding to the rotational speed difference between the input shaft rotation speed Nt of the transmission gear mechanism 15 and the target synchronous rotation speed is calculated with reference to the map of the reduction correction value shown in FIG. By subtracting the reduction correction value from the base hydraulic pressure command value of the engagement side clutch, the hydraulic pressure command value of the engagement side clutch is corrected to obtain the final hydraulic pressure command value of the engagement side clutch.

  The map of the reduction correction value shown in FIG. 9 shows that the reduction correction value increases as the rotational speed difference between the input shaft rotation speed Nt of the transmission gear mechanism 15 and the target synchronous rotation speed is smaller. Is set to increase slowly. As a result, the smaller the rotational speed difference between the input shaft rotational speed Nt of the transmission gear mechanism 15 and the target synchronous rotational speed is, the more gently the engagement force of the engagement side clutch is increased, and the input shaft rotational speed Nt of the transmission gear mechanism 15 is increased. It is set to decrease gradually.

  The method of correcting the hydraulic pressure command value of the engagement side clutch according to the rotational speed difference between the input shaft rotational speed Nt of the transmission gear mechanism 15 and the target synchronous rotational speed may be changed as appropriate. A correction coefficient corresponding to the rotation speed difference between the input shaft rotation speed Nt of the mechanism 15 and the target synchronous rotation speed is calculated from a map or the like, and the base hydraulic pressure command value of the engagement clutch is multiplied by the correction coefficient to thereby engage the engagement side. The clutch hydraulic pressure command value may be corrected to obtain a final engagement clutch hydraulic pressure command value. Alternatively, the final hydraulic pressure command value of the engagement side clutch may be obtained by a map or the like according to the rotational speed difference between the input shaft rotational speed Nt of the transmission gear mechanism 15 and the target synchronous rotational speed. At this time, the hydraulic pressure command value of the engaging clutch may be continuously changed according to the rotational speed difference between the input shaft rotational speed Nt of the transmission gear mechanism 15 and the target synchronous rotational speed, or stepwise. You may make it switch.

  Thereafter, the process proceeds to step 204, where whether the input shaft rotational speed Nt of the transmission gear mechanism 15 has changed due to the pressure increase control is determined, for example, by the input shaft rotational speed Nt before the start of the return control (before the pressure increase control starts) and the current Determination is made based on whether or not the difference from the input shaft rotational speed Nt is equal to or greater than a predetermined value. When it is determined that the input shaft rotational speed Nt has changed, the routine proceeds to step 205 where the input shaft rotational speed of the transmission gear mechanism 15 is changed. It is determined whether or not the rotational speed difference between Nt and the target synchronous rotational speed is equal to or less than a predetermined value.

  If it is determined in step 205 that the rotational speed difference between the input shaft rotational speed Nt of the transmission gear mechanism 15 and the target synchronous rotational speed is equal to or smaller than a predetermined value, the input shaft rotational speed Nt of the transmission gear mechanism 15 has already been determined. Since it is near the target synchronous rotation speed, it is determined that it is not necessary to perform the F / B control, the process proceeds to step 206, and the control stage flag FlagAN is set to “1”.

  On the other hand, if it is determined in step 205 that the rotational speed difference between the input shaft rotational speed Nt of the transmission gear mechanism 15 and the target synchronous rotational speed is greater than a predetermined value, the input shaft rotational speed of the transmission gear mechanism 15 is still Since the speed Nt has not reached the vicinity of the target synchronous rotation speed, it is determined that the F / B control needs to be performed, the process proceeds to step 207, and the control stage flag FlagAN is set to “2”.

  When the control stage flag FlagAN is set to “1” in the above step 206 (when the rotational speed difference between the input shaft rotational speed Nt and the target synchronous rotational speed is equal to or smaller than a predetermined value), the next activation of this routine is performed. Sometimes, from step 201 to step 208, the F / B control is prohibited and the hydraulic pressure command value of the engagement side clutch is maintained at the hydraulic pressure command value at the end of the pressure increase control. The shaft rotational speed Nt is gradually converged to the target synchronous rotational speed.

  Thereafter, the process proceeds to step 209 to determine whether or not the first gear ratio is established, for example, whether the rotational speed difference between the input shaft rotational speed Nt of the transmission gear mechanism 15 and the target synchronous rotational speed is equal to or smaller than a determination value. It is determined by whether or not it has continued for a predetermined time or more. When it is determined that the first gear ratio is established, the process proceeds to step 210, and the control stage flag FlagAN is set to “4”.

  As a result, at the next activation of this routine, the routine proceeds from step 201 to step 217, where the end control for increasing the hydraulic pressure command value of the engagement side clutch to the maximum pressure is executed, and the hydraulic pressure of the engagement side clutch is maximized. After the pressure is raised to a high pressure, the process proceeds to step 215, the control stage flag FlagAN is reset to the initial value “0”, and the return control is completed.

  On the other hand, when the control stage flag FlagAN is set to “2” in step 207 (when the rotational speed difference between the input shaft rotational speed Nt and the target synchronous rotational speed is greater than a predetermined value), the next time When this routine is started, the routine proceeds from step 201 to step 211, where the engagement clutch hydraulic pressure command value is set so that the rate of change (decrease gradient) of the input shaft rotational speed Nt of the transmission gear mechanism 15 matches the target rate of change. The F / B control to be controlled is executed.

  Thereafter, the process proceeds to step 212, and it is determined whether or not the progress rate of the return control has reached a predetermined value. At this time, the progress rate of the return control is, for example, (the difference between the current input shaft rotational speed Nt and the target synchronous rotational speed) / (the input shaft rotational speed Nt before the start of the return control and the target synchronous rotational speed). Rotational speed difference).

When it is determined in step 212 that the return control progress rate has reached a predetermined value, the process proceeds to step 213 and the control stage flag FlagAN is set to “3”.
As a result, at the next startup of this routine, the routine proceeds from step 201 to step 214, where the target change rate is made gentle so that the input shaft rotational speed Nt of the transmission gear mechanism 15 converges gradually toward the target synchronous rotational speed. The soft landing F / B control is performed.

  Thereafter, the process proceeds to step 215 to determine whether or not the first gear ratio has been established, for example, whether the rotational speed difference between the input shaft rotational speed Nt of the transmission gear mechanism 15 and the target synchronous rotational speed is equal to or smaller than a determination value. It is determined by whether or not it has continued for a predetermined time or more. When it is determined that the first gear ratio is established, the process proceeds to step 216, and the control stage flag FlagAN is set to “4”.

  As a result, at the next activation of this routine, the routine proceeds from step 201 to step 217, where the end control for increasing the hydraulic pressure command value of the engagement side clutch to the maximum pressure is executed, and the hydraulic pressure of the engagement side clutch is maximized. After the pressure is raised to a high pressure, the process proceeds to step 218, where the control stage flag FlagAN is reset to the initial value “0” to complete the return control.

  In the present embodiment described above, when the release condition for the pseudo-neutral state is satisfied and the return control for returning the transmission gear mechanism 15 from the pseudo-neutral state to the normal state is performed, the input shaft rotation speed Nt of the transmission gear mechanism 15 is performed. And the target synchronous rotational speed (the rotational speed obtained by multiplying the output shaft rotational speed No of the transmission gear mechanism 15 by the speed ratio of the first gear) is corrected in accordance with the hydraulic command value of the engagement side clutch. Therefore, the rotational speed difference between the input shaft rotational speed Nt of the transmission gear mechanism 15 and the target synchronous rotational speed is small during the pseudo neutral control, and before the effect of the F / B control is obtained, the input shaft rotation of the transmission gear mechanism 15 is achieved. Even when the speed Nt reaches the vicinity of the target synchronous rotation speed, the hydraulic finger of the engagement side clutch is gradually decreased so that the input shaft rotation speed Nt of the transmission gear mechanism 15 is gradually reduced during the return control. By controlling the value, the input shaft rotational speed Nt of the transmission gear mechanism 15 can be gradually converged to the target synchronizing speed, it is possible to prevent the shock occurs.

  In this embodiment, when a change in the input shaft rotational speed Nt of the transmission gear mechanism 15 due to the pressure increase control is detected, the difference between the input shaft rotational speed Nt of the transmission gear mechanism 15 and the target synchronous rotational speed is a predetermined value. In the following cases, since the input shaft rotational speed Nt of the transmission gear mechanism 15 is already near the target synchronous rotational speed, it is determined that there is no need to perform the F / B control, and the F / B control is prohibited. Since the hydraulic pressure command value of the engagement side clutch is maintained at the hydraulic pressure command value at the end of the pressure increase control, the speed change gear mechanism 15 is simplified while the return control for returning from the pseudo neutral state to the normal state is performed. The input shaft rotational speed Nt of the mechanism 15 can be gradually converged to the target synchronous rotational speed.

  In the above embodiment, the present invention is applied to a system that performs pressure increase control and F / B control when performing return control for returning the transmission gear mechanism 15 from the pseudo neutral state to the normal state. The method may be changed as appropriate. For example, the present invention is applied to a system in which the hydraulic pressure command value of the engagement side clutch is controlled with the expectation without performing the pressure increase control or the F / B control in the return control. May be.

It is a schematic block diagram of the whole automatic transmission in one Example of this invention. It is a figure which shows typically the mechanical structure of an automatic transmission. It is a figure which shows the combination of engagement / release of the clutch and brake for each gear position. It is a time chart explaining pseudo neutral control and return control. It is a time chart explaining the return control of a comparative example. It is a time chart explaining the return control of a present Example. It is a flowchart explaining the flow of a process of a return control routine. It is a flowchart explaining the flow of a process of an engagement side clutch hydraulic pressure control routine. It is a figure which shows notionally an example of the map of a weight reduction correction value.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Automatic transmission, 12 ... Torque converter, 15 ... Transmission gear mechanism (transmission mechanism), 16 ... Lock-up clutch, 17 ... Hydraulic control circuit, 20 ... Automatic transmission control circuit, 25 ... Shift lever, 27 ... Engine speed Sensors 28... Input shaft rotational speed sensor 29... Output shaft rotational speed sensor 30... AT-ECU (hydraulic control means), RC, HC, LC .. clutch (friction engagement element), B 0, B 1. Engaging element)

Claims (4)

This is applied to a vehicle that transmits the power of an internal combustion engine to a wheel side via a torque converter and a speed change mechanism, and each frictional force is controlled by individually controlling the hydraulic pressure applied to a plurality of friction engagement elements provided in the speed change mechanism. Hydraulic control means for selectively switching engagement and disengagement of the coupling elements to switch the gear stage of the transmission mechanism, wherein the hydraulic control means is in a state where the vehicle is in a stopped state with a predetermined travel range selected; When the internal combustion engine is in the idling operation state, the engagement force of the engagement side frictional engagement element that is engaged when traveling in the travel range is reduced to make the speed change mechanism in a pseudo neutral state (hereinafter referred to as “pseudo”). In a control device for an automatic transmission that controls a hydraulic pressure command value of the engagement side frictional engagement element so as to be maintained in a "neutral state"),
The hydraulic control means multiplies the input shaft rotational speed of the transmission mechanism and the output shaft rotational speed of the transmission mechanism by the transmission gear ratio at the time of vehicle start when the condition for canceling the pseudo neutral state is satisfied. A control device for an automatic transmission, wherein a hydraulic pressure command value of the engagement side frictional engagement element is changed in accordance with a difference from a rotation speed (hereinafter referred to as "target synchronous rotation speed").   The hydraulic pressure control means executes pressure increase control for increasing a hydraulic pressure command value of the engagement side frictional engagement element with a predetermined gradient when the release condition of the pseudo neutral state is satisfied, and the pressure increase control performs the pressure increase control. After detecting a change in the input shaft rotational speed of the speed change mechanism, feedback control is performed on the hydraulic pressure command value of the engagement side frictional engagement element so that the rate of change of the input shaft rotational speed matches the target value. The control device for an automatic transmission according to claim 1.   When a change in the input shaft rotational speed of the speed change mechanism due to the pressure increase control is detected and the difference between the input shaft rotational speed of the speed change mechanism and the target synchronous rotational speed is a predetermined value or less, the engagement side friction The control apparatus for an automatic transmission according to claim 2, further comprising feedback control prohibiting means for prohibiting feedback control of the hydraulic pressure command value of the engagement element.   The hydraulic pressure control means increases the hydraulic pressure command value of the engagement side frictional engagement element when the feedback control prohibition means prohibits feedback control of the hydraulic pressure command value of the engagement side frictional engagement element. 4. The control apparatus for an automatic transmission according to claim 3, wherein the hydraulic pressure command value at the end of the control is maintained.

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