JP3494875B2 - Control device for automatic transmission - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a neutral transmission for an automatic transmission which shifts the automatic transmission to a neutral state in order to prevent creep under a predetermined condition, and performs learning control of clutch hydraulic pressure in the neutral state. Regarding the control device.

[0002]

2. Description of the Related Art Generally, an automatic transmission for a vehicle is designed to transmit rotational power from an engine to a gear transmission equipped with a clutch via a hydraulic torque converter. , The vehicle speed and the accelerator opening (accelerator depression amount) are changed according to a predetermined shift pattern. The shift range of the automatic transmission includes a drive range (forward drive range), a neutral range, and the like. However, when the drive range is selected, a creep that causes the vehicle to move forward little by little occurs. This is because when the drive range is set, the gear stage of the gear transmission is set to the first speed and the engine is idling, so that some torque is transmitted to the wheel side via the torque converter. .

During actual driving, the creep phenomenon is suppressed by stepping on the foot brake while maintaining the shift range in the drive range. During this period, the load of the creep is applied to the engine, so the fuel consumption of the engine is reduced. It is inevitable that it will get worse.

Therefore, there is a technique for preventing the creep by setting the automatic transmission in the neutral state when the predetermined condition is satisfied even in the drive range.
It is proposed in Japanese Patent No. 5869, Japanese Patent Application Laid-Open No. 6-147312, and the like. The predetermined conditions in this case are:
It is usually said that the accelerator is released (fully closed), the foot brake is depressed, and the vehicle speed is detected to be substantially zero.

Further, when the neutral state is formed under the condition that the vehicle is stopped, the clutch hydraulic pressure can be set to a value immediately before the clutch has a capacity and the value can be learned. , JP-A-7-293687, and JP-A-8-128527. In this case, the change in rotational speed between the engine speed and the main shaft speed of the automatic transmission is monitored, and if there is no change in differential speed, the clutch hydraulic pressure is increased by a specified amount. By reducing the set amount by a predetermined amount, an appropriate learning value is searched for.

[0006]

By the way, when the vehicle is stopped by a red signal or the like, the brake is stepped on and the vehicle is gradually decelerated to stop. At this time, immediately before the vehicle actually stops. (About 3 m before the target stop position), that is, at a very low speed (a speed around 11 km / h),
A downshift to the lowest speed (first speed) occurs. Therefore, in a vehicle equipped with the above-mentioned creep prevention device (= neutral control device), after traveling a certain distance (about 3 m) in the first speed state, the vehicle stops and shifts to the neutral state for the first time at that stage. Will be done.

However, in reality, in the case where the vehicle is decelerated at the first speed immediately before the stop when the braking is gently applied, the engine braking is not expected so much, and accordingly, the fuel consumption by the neutral control is correspondingly increased. There was a problem that the saving effect weakened.

Therefore, the applicant of the present invention thought that the fuel economy could be further improved by forming the neutral state at a certain timing immediately before the vehicle actually stops. However, in doing so, the learning control method described in the conventional publication makes the learning control of the clutch hydraulic pressure unstable, and there is a concern that there may be a case where proper learning cannot be actually performed.

In view of the above circumstances, it is an object of the present invention to provide an automatic transmission control device capable of further improving the fuel consumption saving effect and optimizing the learning control of the clutch hydraulic pressure.

[0010]

According to the invention of claim 1, even when the shift range is set to the travel range, the automatic transmission is set to the neutral state when the predetermined condition is satisfied, and the automatic transmission is set to the neutral state. In a control device for an automatic transmission that performs clutch hydraulic pressure learning control for learning a clutch hydraulic pressure at which a clutch of a transmission has a predetermined torque transmission capacity, (a) accelerator opening is used as means for determining whether the predetermined condition is satisfied. Means for determining that the value is less than or equal to a predetermined value (b) Means for determining that the brake is depressed (c) Vehicle speed is 1 speed
Shift down to the driving range Judge that the vehicle speed is below
Means provided with a that, when all of the determination means these determines the establishment of the condition, with a neutral control execution means to shift the automatic transmission to the neutral state, the New
The automatic transmission is updated by means of the general control execution means.
After shifting to the neutral state, a neutral state determination means for determining that the neutral state is established based on the relationship between the engine rotational speed and the main shaft rotational speed of the automatic transmission, and an idle state determination engine for determining that the engine is in the idle state. And a learning control start permission unit that permits the start of the learning control of the clutch hydraulic pressure when the determination unit determines that the neutral state is established and is in the idle state.

According to this apparatus, even when the vehicle speed is not always zero (for example, the vehicle speed is 11 km or less), the neutral state may be entered. At that stage, depending on the results of the neutral state determining means and the idle state determining means. , The learning control start permission means does not permit the start of learning control, the vehicle finally stops, the neutral state is completely established, and the learning control is started only when the engine speed and the main shaft speed are stable. To do. Therefore, highly accurate learning is possible.

Further, in claim 1, the learning control start permitting means starts learning control of the clutch hydraulic pressure a predetermined time after the determination means determines that the neutral state is established and the idle state is established. It is also possible to permit.

In this apparatus, even if the neutral state is completely established and the idle state is entered, the learning control is not performed immediately, but after a short time, more appropriate learning control is possible.

According to a second aspect of the present invention, in the first aspect, when the learning control start permission means does not permit the start of the learning control of the clutch hydraulic pressure, the value based on the learning value obtained by the learning control up to the previous time is set. A clutch hydraulic pressure setting means for setting the clutch hydraulic pressure command value during the neutral control is provided.

In this device, when the learning control cannot be performed, the clutch hydraulic pressure is set by using the learning value up to the previous time. Therefore, even in the neutral state, the clutch is always made to stand by in the state immediately before having the capacity. The clutch can be set, and the clutch can be immediately put into the engaged state when a command to release the neutral state is issued.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. First, the configuration of the control device according to the embodiment will be described with reference to FIG. This control device sets the automatic transmission to a neutral state with respect to a clutch hydraulic pressure control means 2 that controls the hydraulic pressure of a clutch (here, the clutch on the engagement side for forming the first speed) 1 of the automatic transmission. It has a neutral control means 3 for giving a command for The neutral control means 3 includes a signal from the range detection means 4, a signal from the accelerator opening detection means 5, a signal from the brake operation detection means 6, a signal from the downshift detection means 7, a signal from the vehicle speed detection means 8, and an engine cooling. A signal from the water temperature detecting means 9 and a signal from the automatic transmission oil temperature detecting means 10 are input.

On the basis of these signals, the neutral control means 3 operates in the case where the shift range is the forward traveling range, (a) the accelerator opening is below a predetermined value, and (b) the brake is depressed (c). ) It is the timing at which the downshift is performed. (D) Condition satisfaction determination means 3A that determines that the automatic transmission should be set to the neutral state, with the main condition of the predetermined condition being that the vehicle speed is below a predetermined value. , The clutch hydraulic pressure control means 2 when the condition is satisfied
Includes a neutral control execution means 3B for issuing a signal for instructing the transition to the neutral state. The condition determination unit 3A determines to prohibit the shift to the neutral state when the temperature of the engine cooling water is below a predetermined value and when the oil temperature of the automatic transmission is below a predetermined value. Has become.

Further, this control device sets the clutch hydraulic pressure to a value immediately before the clutch starts to have a capacity when the neutral state is formed, and the learning control executing means 11 for learning the value. The learning control start permission means 12 for permitting the start and the learning control stop means 17 for stopping the learning control are included.

The learning control permitting means 12 learns the clutch hydraulic pressure when the neutral state determining means 16 determines that the neutral state is completely established and the idle state determining means 13 determines that the neutral state is currently in the idle state. Allow control to start. Neutral state determination means 16
Is a predetermined time (time that can be estimated that the neutral state is sufficiently formed) after the command to shift to the neutral state is issued, and the engine speed NE detected by the engine speed detecting means 14 (of the torque converter The relationship between the input rotational speed) and the main shaft rotational speed NM (output rotational speed of the torque converter) detected by the main shaft rotational speed detection means 15 of the automatic transmission is NM ≧ NE * 0.
When 9 (however, "*" represents "x"),
Judge that the neutral state is completely established. In addition,
As the idle state determination means 13, it is also possible to employ means for detecting that the vehicle speed has become substantially zero.

Further, this control device has a learning control stopping means 17 for stopping the learning control when a certain condition is satisfied. A certain condition in this case is a ratio ETR (= NE) of the main shaft rotation speed NM of the automatic transmission and the engine rotation speed NE in the state where the neutral state is formed.
/ NM = slip ratio of torque converter), and in order to detect the sudden change, the learning control stopping means 17 includes:
The signal of the ETR calculation means 18 is input. And
When the learning control stop means 17 detects a sudden change in the ETR, the learning control stop means 17 lowers the clutch hydraulic pressure and issues a command to stop the learning control. In other words, at the time of learning, the value immediately before the clutch starts to grab (immediately before starting to hold the capacity) is learned, but even if the value is learned with a large grip, it will be erroneous learning. If it can be judged that the player has grabbed a large amount, learning is stopped.

When the learning control start permission means 12 does not permit the start of the clutch hydraulic pressure learning control, the clutch hydraulic pressure control means 2 determines the value (learning value) based on the learning value obtained in the previous learning control. (Slightly smaller value)
Is set as the clutch hydraulic pressure command value during the neutral control.

Here, the structure of the driving force transmission system in the vehicle of the embodiment will be briefly described. This driving force transmission system is of a parallel biaxial type as shown in FIG. 2, and the driving force of the engine is transmitted to the transmission input shaft X via the torque converter TC and the lockup clutch L, and the gear shifting is performed. It is transmitted from the machine input shaft X to the transmission output shaft Y via the clutch C. In the figure, reference symbol Tt is turbine torque, To
ut represents the output torque, Nout represents the output shaft rotation speed, and the symbol i represents the gear ratio.

Next, the contents of the control performed by the control device will be described in detail with reference to the flow chart. FIG. 3 defines the process up to setting the flag NEUG for performing the neutral control, and FIG. 3 shows the details of step S2 in the process. When the process of FIG. 3 starts, it is determined in a first step S1 whether or not the neutral control flag F-NEUG is 1.
If YES, this routine process is terminated, and if NO, the process proceeds to step S2 to make a neutral control permission decision.

As shown in FIG. 4, when the routine process for determining permission is started, the current shift range is checked in step S21. That is, the shift range is D4
Or not. This step S21 is D4.
Neutral control is not performed outside the range, so it is provided to check it. That is, the shift position in which the shift such as the second speed range and the first speed range is held is selected because it is necessary for the driver to drive (engine braking etc.), and at that time, the neutral control is not performed. This is because. D4 in this case
The range refers to a forward traveling range including the highest speed.

In step S22, it is checked whether the oil temperature TATF of the automatic transmission is a predetermined value (for example, 60 degrees) or more, and in step S23, the engine cooling water temperature TW is a predetermined value (for example, 70 degrees) or more. Then, in step S24, it is checked whether or not the accelerator pedal is released, and in step S25, it is checked whether or not the foot brake is depressed. The determination in step S24 is whether or not the current accelerator opening AP is smaller than a predetermined value APZ (a value that can substantially determine whether the accelerator pedal is fully closed) or whether a flag APZ that indicates the accelerator pedal is fully closed is set to 1. Done in. Further, the determination in step S25 is that the brake is ON.
This is performed depending on whether or not the flag BRK indicating 1 is set.

If all the conditions are YES, step S2
Proceeding to step 6, the permission flag F-N for shifting to neutral control
Set up EUOK. Also, if even one of the conditions is not met, in order not to allow the transition to neutral control,
In step S27, the shift permission flag F-NEUOK to the neutral control is reset, and the neutral control start delay timer tmNEUON is set to a predetermined stored value tmNEUONS (for example, about 100 ms).

The reason why the neutral control is not performed when the oil temperature condition is not OK is that the response of the automatic transmission is poor when the oil temperature is low and the controllability at the time of restarting becomes poor. . In addition, the neutral control is not performed when the water temperature condition is not OK,
This is because the idling speed is high when the water temperature is low. The neutral state in this device does not mean that the clutch hydraulic pressure is set to zero, but it is a marginal state where torque is transmitted when the hydraulic pressure is raised even slightly, that is, the driver's braking operation or accelerator pedal depression operation. In this case, it refers to a delicate state in which the vehicle can get out of the neutral state with high response. Therefore, in the case where it is an obstacle to secure such a delicate state, the oil temperature condition and the water temperature It is excluded by the judgment of the conditions.

Returning to FIG. 3, after the process of step S2, the process proceeds to step S3 to check the state of the shift permission flag F-NEUOK to the neutral control. If the flag F-NEUOK is set, it means that the precondition for shifting to the neutral control has been passed.
The process proceeds to the actual condition determination after step S4. Flag F-NE
If UOK is not set, then in step 10, the flag NEUG indicating that the neutral control is in progress is set to zero, and the process is terminated.

In step S4, the timing at which a downshift command from 3rd speed → 1st speed or 2nd speed → 1st speed is generated is detected. This downshift command is predetermined for each shift range. For example, in the case of the D4 range,
Depending on the throttle opening (or accelerator pedal opening) and the vehicle speed, a downshift command is generated when the vehicle crosses a shift line on the downshift side (to the 1st speed operation range) in a predetermined shift map. Has become. Therefore, the current throttle opening and vehicle speed are detected,
As a result of comparison with the shift line of the shift map, a downshift command is generated.

In the present embodiment, the timing of the downshift means that the engagement is currently performed by the downshift command from the time the downshift command is issued.
It can be arbitrarily set until the disengagement of the first-speed or second-speed clutch (when the clutch has no transmission capacity). For example, when a command to release the engaging force of the currently engaged clutch based on a downshift command is issued, or when there is a change in the rotational speed between the input side and the output side of the currently engaged clutch When I did it. That is, step S4 is intentionally provided because the neutral control is executed in synchronization with the timing of disengaging the clutch that has been engaged by the downshift.

When the downshift timing is detected in step S4 (when the determination in step S4 is YES),
In step S5, the vehicle speed at that moment is checked. Vehicle speed V
Is smaller than a predetermined value VNDOWN (for example, a value near 11 km / h at which a downshift to the 1st speed occurs), the process proceeds to step S6 to set a flag F-NEUG which indicates that the neutral control is being performed, and the timer. tmNEU
Set the CUT. This timer tmNEUCUT is
It is a timer that confirms by time whether the clutch hydraulic pressure is completely released after starting the neutral control.
It is set to a value in seconds. Then, when the processing of this step S6 is completed, this routine processing is ended.

If it is not the downshift timing,
Alternatively, if the vehicle speed has not decreased even at the downshift timing, the process proceeds to step S7. In this step S7, it is determined whether or not the vehicle has stopped by checking whether or not the vehicle speed V has become smaller than a predetermined value VNEUN (a value near 1 km / h which can be regarded as substantially zero vehicle speed). There is. If not stopped, step S8
To the neutral control start delay timer tmN
A predetermined storage value tmNEUONS (for example, about 1 second) is set in EUON. If stopped, the process proceeds from step S8 to step S9, waits for the neutral control start delay timer tmNEUNON to count up, and then proceeds to step S6 described above to set the flag F-NEUG indicating that the neutral control is being performed. Stand up.

Next, the routine shown in FIG. 5 is executed. In this routine, it is determined in step S31 whether the flag F-NEUG indicating that the neutral control is being performed is set, and Y
In the case of ES, the process proceeds to the neutral control subroutine of step S32, and in the case of NO, the process proceeds to the in-gear subroutine of step S33.

In the neutral control subroutine, the clutch of the automatic transmission is released to create the neutral state. When the brake is turned off or the accelerator is depressed in the neutral state, the neutral state is stopped and the normal control is resumed.

When such neutral control is executed, the vehicle is already in the neutral state before the vehicle actually stops, so that fuel consumption can be reduced accordingly. Further, since the shift to the neutral state is made at the timing of downshifting from the third speed → the first speed or the second speed → the first speed, the downshift to the first speed stage (the establishment of the gear stage) does not actually occur. Therefore, the downshift to the first speed is eliminated, and the neutral state is shifted to the neutral state at the downshift timing instead of shifting to the neutral state in the stationary state, which causes a slight shock to the driver. Can also be relaxed.

Step S32 of the above neutral control
After proceeding to step 3, the neutral standby control (hereinafter referred to as N standby control) 34 is executed as it is. The N-standby control is executed when in the neutral state, and its contents will be described below with reference to the flowchart of FIG. 6 and the time chart of FIG. 7.

When this flow is entered, it is checked in step S41 whether the timer tmNEUCUT is counting "t".
Check whether mNEUCUT> 0 ”, and then step S
At 42, check whether the main shaft rotation has returned to near engine rotation by "NM <NE * 0.9 (or 0.9
5) ”or not. If YES in any case, the process proceeds to step S43. Here, YES means that the neutral state has not been completely established. In other words, it is determined in step S41 that the clutch hydraulic pressure is not completely cut off, and in step S42 it is determined that the main shaft rotation speed NM has not yet returned to a value close to the engine rotation speed NE. Therefore, there is a possibility that the neutral state is not yet completely formed. Therefore, in step S43, the clutch hydraulic pressure calculated value QON is set to "0" in order to achieve the complete neutral state. In actual control, this calculated value QON may be used as the clutch hydraulic pressure command value QAT as it is, but in this control device, QON and QAT may be considered to be the same.

If both the determinations in step S41 and step S42 are NO, it is considered that the neutral state is completely entered, and it is determined in step S44 whether or not the engine is in the idle state. This determination has the same meaning as determining whether the vehicle speed is 1 km or less, that is, whether or not the vehicle is almost stopped. Being idle means that the vehicle speed has dropped sufficiently. Also, if the vehicle is not idle, it can be considered that the vehicle speed has not dropped sufficiently. If the vehicle speed has not dropped sufficiently, that is, if the vehicle is not idling, the learning control of the clutch hydraulic pressure is not performed. Therefore, the process proceeds from step S44 to steps S45 and S46,
At 46, the clutch hydraulic pressure calculated value QON is obtained based on the clutch hydraulic pressure learned value QATG up to the previous time. That is, Q
A value obtained by multiplying ATG by a coefficient KQSTNBY smaller than 1 (QATG * KQSTNBY) is the clutch hydraulic pressure calculated value Q.
Set as ON. Further, in step S45 before that, the learning control delay timer tmNS after the idle determination is performed.
Set T. This delay timer is for waiting the start of the learning control for a predetermined time (for example, about 1 second) for the purpose of ensuring reliability when the idle state is changed to the idle state.

On the other hand, if the vehicle is idle, step S4
4 to step S47, the delay timer tm
Determine if NST is operating. This timer tmNS
T is used as a guide for determining whether or not the vehicle has definitely stopped. If the vehicle is operating, it is determined that the vehicle is not stopped sufficiently, and the process proceeds to step S46. If the vehicle is operating, it is considered that the vehicle is sufficiently stopped, and the process proceeds to step S48 to enter the learning control of the clutch hydraulic pressure command value QAT.

Looking at the flow described so far in the time chart of FIG. 7, the N standby control starts and the range of HA corresponds to the flow of steps S41 → 43. The range of HB corresponds to the flow of steps S41 → 42 → 43. H
The range of C is steps S41 → 42 → 44 → 45 → 46,
Alternatively, it corresponds to the flow of steps S41 → 42 → 44 → 47 → 46. HD range is step S41 → 42 → 44
This corresponds to the flow of → 47 → 48.

Next, the content of the learning control of the clutch hydraulic pressure command value QAT will be described with reference to the flowchart of FIG. 8 and the time chart of FIG. When entering this flow, step S
At 51, the calculated clutch oil pressure QON is QON <QATG.
* Whether or not it is KQSTD, that is, QON is the minimum command Q
Determine if lower than AT. KQSTD is a coefficient. If it is lower than the minimum command value, the process proceeds to step S52, where the learning value QATG obtained by learning up to the previous time is set as the initial value.
The value "QATG * KQSTD" (this is the minimum command value) based on is substituted (the portion A of the time chart).

In the next step S53, it is determined whether or not the smoothing timer tmNWS is in operation. If it is in operation, the process proceeds to step S54, in which the average ETR value ETR.
The AVE value is stored as a reference value ETRA for determining a change in ETR. If the timer tmNWS is not operating, the process proceeds to step S55, and it is determined whether the timer tmWAIT is operating. The timer tmWAIT sets a time (for example, 1 second) as a step width when the clutch hydraulic pressure is increased stepwise in a small width for learning. When this timer is not operating, the routine proceeds to step S56, where the clutch hydraulic pressure calculated value QON is set to the current QON by a predetermined increment QNDS.
Set the value with T added. Next, the timer tmWAIT is set in step S57, and the counter cNMDN is reset in step S58.

In the next process, if the timer tmNWS is not operating and the timer tmWAIT has finished counting, the process proceeds to steps S56 → 57 → 58. Therefore, FIG.
As shown in (B) of the time chart of
The clutch hydraulic pressure QON is gradually increased for each time width set by AIT. On the other hand, when the timer tmWAIT is operating, the process proceeds to steps S53 → 55 → 59. In step S59, it is determined whether the ETR has changed significantly by "ET
It is determined whether or not R <ETRA-DETRSTX. If the determination is NO, it is determined whether or not the ETR is changed small in step S60 based on whether or not “ETR <ETRA-DETRST”. However, DETRSTX, DETRST
Is a constant, and DETRSTX is a value considerably larger than DETRST. If the determinations in steps S59 and S60 are both NO, this routine ends.

If the determination in step S60 is yes,
In step S61, the counter cNMDN is incremented. The process proceeds through this flow several times, and when the value of the counter cNMDN reaches the set value THRNMDN as shown in (C) of the time chart, the determination in step S62 becomes YES and the process proceeds to step S63. Then, the current QON is stored as the learning value QATG (the learning value is the point P1 in the D portion of the time chart). That is, ET
Counting is started by a slight change in R, and if it is confirmed by the count number that the minute change continues, the clutch hydraulic pressure at that time is learned. At the same time as learning, the clutch hydraulic pressure is changed to "QON-NSBK * QND" in step S63.
ST ". And at that time, the timer tmW
AIT (timer of about 1 second) is reset to zero, and a timer tmNWS for smoothing is set. Therefore. In the next process, the determination in step S53 is YES, and the process proceeds to step S54 to update ETRA. The smoothed time is the section (E) shown in the time chart.

Next, when the clutch hydraulic pressure is increased in the same manner as described above and a large change in ETR appears, the determination at step S59 becomes YES and the routine proceeds to step S64.
If the change in ETR is large, it is considered that the clutch is over-grasped, so the learning of the clutch hydraulic pressure is temporarily stopped at this point (the portion indicated by F in the time chart), and the clutch hydraulic pressure P2 at that time is memorized. Discard without doing. Then, in step S64, in order to immediately reduce the clutch hydraulic pressure, QON is set to "QON-QNDST * N".
SBK * 2 ”is set. In other words, the reduction of 2 when learning
Double decrease the clutch hydraulic pressure. At the same time, the timer tmWAIT is reset to zero, and the smoothing timer tmNWS is set. Therefore. The same time is repeated after the lapse of time.

According to this control device, as shown in the flowchart of FIG. 6 and the time chart of FIG. 7, the learning control of the clutch hydraulic pressure in the neutral state is performed only when the neutral state is completely established and the idle state is established. Since the engine speed NE and the main shaft speed NM are stable, highly accurate learning control can be performed. In particular, even if the neutral state is completely established and the idle state is entered, the learning control is not performed immediately, but the learning is performed after the stability increases after waiting for the set time of the timer tmNST, so that more appropriate learning control is performed. You can Also, even if learning control is not allowed,
Clutch hydraulic pressure QO using the learned value QATG up to the previous time
Since N is set, the responsiveness up to clutch engagement is improved when a neutral state release command is issued.

Further, after the learning control is started, the learning timing is set by the change of the slip ratio ETR of the torque converter. Therefore, unlike the conventional case in which the differential rotation of NE and NM is performed, the rotational change is made with a sharp waveform. It can be captured and the accuracy of learning can be improved. Further, when the ETR suddenly changes, the learning of the clutch hydraulic pressure is stopped for a while to reduce the clutch hydraulic pressure, so that the risk of erroneous learning can be eliminated.

As in the parallel biaxial type, it is possible to form the second gear by grasping the second gear (second clutch) without engaging the first gear (first clutch). In the case of such an automatic transmission, it is possible to learn the hydraulic pressure of the second speed clutch in the neutral state. In that case, in the neutral state, the first speed clutch
Wait at a hydraulic pressure value less than or equal to the learning value of the hydraulic pressure of the fast clutch,
In that state, the second speed clutch may be set to a value immediately before the second speed clutch has a capacity and the value may be learned. That way, when you get out of neutral,
By stopping the learning of the high speed clutch and introducing the hydraulic pressure to the first speed clutch, it is possible to immediately form the first speed stage and start the vehicle.

[0049]

As described above, according to the first aspect of the present invention, the learning control of the clutch hydraulic pressure in the neutral state is performed only when the neutral state is established and the idle state is established. High-accuracy learning control can be performed while the shaft rotation speed is stable.

Further , even if the neutral state is established and the idle state is entered, the learning control is not performed immediately, but the learning is performed after the stability is increased after a while, so that more appropriate learning control can be performed. become.

According to the second aspect of the present invention, when the learning control is not permitted, the clutch hydraulic pressure is set by using the learning value up to the previous time, so that it is possible to immediately respond to the case where the neutral state cancellation command is issued. .

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a control device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a schematic configuration of a driving force transmission system in the vehicle of the same embodiment.

FIG. 3 is a flowchart showing the processing contents of the control device of FIG.

FIG. 4 is a flowchart showing a subroutine of step S2 in the flowchart of FIG.

FIG. 5 is a flowchart showing a routine executed after the flow of FIG.

FIG. 6 is a flowchart showing a subroutine of step S34 in the flow of FIG.

FIG. 7 is a time chart corresponding to the contents of the flow of FIG.

FIG. 8 is a flowchart showing a subroutine of step S48 in the flow of FIG.

9 is a time chart corresponding to the contents of the flow of FIG.

[Explanation of symbols]

1 clutch of automatic transmission 2 clutch hydraulic pressure control means 3 neutral control execution means (neutral control means) 4 range detection means 5 accelerator opening detection means 6 brake operation detection means 7 downshift detection means 8 vehicle speed detection means 11 learning control execution means 12 Learning Control Start Permitting Means 13 Idle State Determining Means 14 Engine Revolution NE Detecting Means 15 Main Shaft Revolution NM Detecting Means 16 Neutral State Determining Means 17 Learning Control Stopping Means 18 ETR (NE / NM) Computing Means

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-9-72416 (JP, A) JP-A-7-293687 (JP, A) JP-A-6-147312 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) F16H 59/00-63/48

Claims (2)

(57) [Claims] 1. An automatic transmission is placed in a neutral state and a clutch of the automatic transmission has a predetermined torque transmission capacity when a predetermined condition is satisfied even when the shift range is set to a travel range. In the control device of the automatic transmission for performing the clutch hydraulic pressure learning control for learning the following clutch hydraulic pressure, as means for determining whether the predetermined condition is satisfied, (a) means for determining that the accelerator opening is equal to or less than a predetermined value ( b) Means for determining that the brake is depressed (c) The vehicle speed is equal to or lower than the downshift vehicle speed to the first speed operation range.
Provided with a means for determining that there, when all of the determination means these determines the establishment of the condition, with a neutral control execution means to shift the automatic transmission to the neutral state, the neutral control execution means, said self
After shifting the dynamic transmission to the neutral state, the neutral state determining means for determining that the neutral state is established from the relationship between the engine speed and the main shaft rotational speed of the automatic transmission, and the engine being in the idle state. And a learning control start permitting means for permitting the start of the clutch hydraulic pressure learning control when the determining means determines that the neutral state is established and is in the idle state. Characteristic automatic transmission control device. 2. When the learning control start permitting unit does not permit the start of the clutch hydraulic pressure learning control, a value based on the learning value obtained by the previous learning control is used as the clutch hydraulic pressure command value during the neutral control. The control device for an automatic transmission according to claim 1, further comprising clutch hydraulic pressure control means for setting.