JP2002081535A - Control device for automatic transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To converge racing in a short time in an automatic transmission in which engagement of different friction engagement elements is changed for speed changing while controlling accumulator back pressure. SOLUTION: When generation of racing is detected at the time of up-shifting from a second gear speed to a third gear speed for fastening a high clutch H/C simultaneously as a brake band 2 and 4/B is released, accumulator back pressure of the high clutch H/C is increased stepwise, and on detecting convergence of racing, increasing correction to the accumulator back pressure in steps is stopped.

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, and more particularly, to a technique for suppressing the occurrence of idling during speed change control.

[0002]

2. Description of the Related Art Conventionally, there has been known an automatic transmission configured to perform a shift by changing a friction engagement element that simultaneously performs engagement control and release control of two different friction engagement elements. As a shift control device for performing the shift change of the friction engagement element, for example, Japanese Patent Laid-Open No. 11-03032
As disclosed in Japanese Patent Laid-Open No. 4 (1999) -1994, an accumulator is provided in a supply path of oil to each friction engagement element, and a gradient of an increase or a decrease in hydraulic pressure is suppressed by controlling a back pressure of the accumulator. There was something.

[0003] On the other hand, in the above-described shift control device for performing a shift change of the friction engagement element, as a technique for suppressing the occurrence of idling at the time of shifting, Japanese Patent Laid-Open Nos. 7-012210, 5-039843 and JP 2000
There was one disclosed in Japanese Patent Application Publication No. 055180. In the device disclosed in Japanese Patent Application Laid-Open No. H07-122210, a pressure switch detects an increase in the hydraulic pressure of the engagement-side frictional engagement element and determines the timing for releasing the hydraulic pressure of the release-side frictional engagement element. I have.

[0004] Further, in Japanese Patent Laying-Open No. 5-039843, when the slip amount of the disengagement side frictional engagement element is equal to or more than a threshold value, the hydraulic pressure of the disengagement side frictional engagement element is increased. When the rate of change of the slip amount is 0 or less, the hydraulic pressure of the disengagement-side friction engagement element is reduced. Further, in Japanese Patent Application Laid-Open No. 2000-0555180, the stroke completion of the engagement-side friction engagement element is predicted, and the line pressure is reduced by timing the stroke completion.

[0005]

However, the configuration using a pressure switch has a problem that the system cost of the automatic transmission increases because the pressure switch is generally expensive. In the configuration in which the hydraulic pressure is controlled in accordance with the slip amount of the release-side friction engagement element, the shift time is extended because the hydraulic pressure of the release-side friction engagement element is controlled to converge so as to maintain the small slip amount. As a result, there is a possibility that the shifting performance is deteriorated.

Further, in a configuration in which the line pressure is reduced by timing the completion of the stroke of the engagement side frictional engagement element,
Due to a prediction error at the time of completion of the stroke, the occurrence of idling cannot be suppressed stably, and a decrease in the line pressure (original pressure) in the torque phase causes a decrease in the responsiveness of the clutch hydraulic pressure. There was a possibility that it would promote the blowing.

Further, as disclosed in Japanese Patent Application Laid-Open No. H11-030324, the timing of draining the accumulator back pressure of the disengagement side frictional engagement element is controlled based on the accumulator back pressure of the engagement side frictional engagement element. In this configuration, the torque capacity on the release side can be reduced at the timing when the torque capacity on the engagement side is secured by setting the back pressure on the accumulator on the engagement side optimally. Since the oil in the joint element and the hydraulic path escapes, the hydraulic response on the engagement side is slowed down at the time of shifting for the first time after the start of the operation, and there is a possibility that a large air blow is generated.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and in an automatic transmission for performing a shift change by controlling the back pressure of an accumulator, the cost does not increase and the shift time is not prolonged. It is an object of the present invention to be able to stably suppress the occurrence of air blowing.

[0009]

Therefore, according to the first aspect of the present invention, while controlling the back pressure of the accumulator, the frictional engagement element for simultaneously performing the engagement control and the release control of two different frictional engagement elements is controlled. A control device for an automatic transmission configured to shift by shifting, wherein when an idle engine blow is detected during shifting, the accumulator back pressure of the engagement side frictional engagement element is stepwise increased and corrected. did.

According to this configuration, by increasing and correcting the back pressure of the accumulator on the engagement side, the engagement pressure of the engagement side frictional engagement element is started up in a responsive manner, thereby converging the idling state due to insufficient torque capacity. According to the second aspect of the present invention, the stepwise increase correction amount of the back pressure of the accumulator is determined according to at least one of the engine speed and the temperature of the hydraulic oil.

According to this configuration, the correction amount when the accumulator back pressure of the engagement-side frictional engagement element is stepwise increased and corrected is correlated with the engine rotation speed correlated with the discharge amount of the oil pump driven by the engine, and / or Is determined according to the oil temperature correlated with the viscosity of the hydraulic oil. According to the third aspect of the present invention, the accumulator back pressure of the engagement-side frictional engagement element is controlled to the maximum hydraulic pressure for a predetermined period from the start of the gear shift, while the predetermined period is at least the engine rotation speed and the temperature of the hydraulic oil. The configuration is determined according to one of them.

[0012] According to this configuration, the pre-charge control for controlling the accumulator back pressure of the engagement-side friction engagement element to the maximum hydraulic pressure for a predetermined period from the start of the shift operation causes the engagement-side friction engagement element to be filled with oil. The period of the precharge control is determined according to an engine rotation speed correlated with a discharge amount of an oil pump driven by the engine and / or an oil temperature correlated with a viscosity of hydraulic oil.

According to the present invention, the occurrence of idling is determined by determining the difference between the input shaft rotation speed of the transmission mechanism and the reference input shaft rotation speed calculated from the output shaft rotation speed of the transmission mechanism and the gear ratio before shifting. The detection is performed according to the deviation. According to this configuration, from the output shaft rotation speed and the gear ratio before shifting,
The input shaft rotation speed when the gear ratio of the transmission mechanism maintains the gear ratio before the gear shift is calculated, and the calculated input shaft rotation speed (reference turbine rotation speed) is used as the actual input shaft rotation speed (turbine rotation speed). And when the actual input shaft rotation speed exceeds the reference input shaft rotation speed by a predetermined value or more, the occurrence of idling is detected.

According to the fifth aspect of the present invention, the convergence of the idling is determined by comparing the input shaft rotation speed of the transmission mechanism with the reference input shaft rotation speed calculated from the output shaft rotation speed of the transmission mechanism and the gear ratio before the shift. The detection is performed based on the differential value of the deviation. According to this configuration, whether the actual input shaft rotation speed is deviating from the reference input shaft rotation speed, which is the input shaft rotation speed when the gear ratio of the transmission mechanism maintains the gear ratio before the shift, or the reference input shaft rotation speed It is determined whether the actual input shaft rotation speed is approaching based on the differential value of the difference between the actual input shaft rotation speed and the reference input shaft rotation speed to detect the convergence of the airflow.

According to the present invention, the occurrence and convergence of the idling are detected based on a comparison between a gear ratio calculated from the input shaft rotation speed and the output shaft rotation speed of the transmission mechanism and a predetermined value. did. According to this configuration, the gear ratio is calculated from the input shaft rotation speed and the output shaft rotation speed of the transmission mechanism,
When the input shaft rotation speed increases with respect to the output shaft rotation speed and the gear ratio (gear ratio = input shaft rotation speed / output shaft rotation speed) exceeds a predetermined value, occurrence of idling is detected and the input shaft is detected. When the gear ratio becomes smaller than a predetermined value due to a decrease in the rotation speed, the convergence of the wind blow is detected.

[0016]

According to the first aspect of the present invention, when an idling occurs, the torque capacity of the engagement-side frictional engagement element is increased with a good response, so that the idling can be quickly converged. There is. According to the invention described in claim 2,
The accumulator back pressure rise control is optimally controlled according to the change in the discharge amount of the oil pump and the viscosity of the hydraulic oil, so that the torque capacity of the engagement side frictional engagement element can be increased without excess and deficiency. is there.

According to the third aspect of the present invention, by pre-charging the oil to the engagement-side frictional engagement element, it is possible to ensure the responsiveness of the hydraulic pressure in the engagement-side frictional engagement element, thereby generating the idling. Can be suppressed more effectively.
According to the fourth aspect of the present invention, there is an effect that the occurrence of an idling can be detected accurately and responsively even when the vehicle speed changes.

According to the fifth aspect of the present invention, the convergence of the idling can be detected with good response and high accuracy as the time point at which the input shaft rotation speed switches to the rotation speed before shifting. There is. According to the sixth aspect of the invention, there is an effect that the occurrence and convergence of the blowing can be easily detected regardless of a change in the vehicle speed.

[0019]

Embodiments of the present invention will be described below. FIG. 1 shows a drive system of a vehicle according to an embodiment. An automatic transmission 103 is connected to an output shaft of an engine 101 via a torque converter 102, and the output shaft of the automatic transmission 103 is shown in FIG. The driving wheels of the vehicle that do not rotate are driven.

The automatic transmission 103 includes a transmission mechanism 10
3A and a control valve section 103B. The control valve section 103B is controlled by an A / T controller 104. The A / T controller 104 incorporates a microcomputer, and includes an A / T oil temperature sensor 105, an accelerator opening sensor 106, a vehicle speed sensor 1
07, a turbine rotation sensor 108, an engine rotation sensor 109, an arithmetic processing of detection signals from the air flow meter 110, etc., to output a control signal to the control valve section 103B.

FIG. 2 is a skeleton showing the transmission mechanism 103A. The transmission mechanism 103A includes two sets of planetary gears G1, G2 and three sets of multi-plate clutches (high clutch H /
C, reverse clutch R / C, low clutch L / C),
It is composed of one set of brake bands 2 & 4 / B, one set of multiple disc brakes (low & reverse brake L & R / B), and one set of one-way clutch L / OWC.

The two sets of planetary gears G1 and G2 are simple planetary gears including sun gears S1 and S2, ring gears r1 and r2, and carriers c1 and c2, respectively. The sun gear S1 of the planetary gear set G1 has a reverse clutch R /
C is configured to be connectable to the input shaft IN, and is configured to be fixable by the brake bands 2 & 4 / B.

The sun gear S2 of the planetary gear set G2 is directly connected to the input shaft IN. The carrier c1 of the planetary gear set G1 is configured to be able to be coupled to the input shaft IN by a high clutch H / C, while the ring gear r2 of the planetary gear set G2 is connected to the carrier of the planetary gear set G1 by a low clutch L / C. The carrier c1 of the planetary gear set G1 can be fixed by a low & reverse brake L & R / B.

The ring gear r1 of the planetary gear set G1 and the carrier c2 of the planetary gear set G2 are directly and integrally connected to the output shaft OUT. In the transmission mechanism 103A having the above configuration, the first to fourth speeds of forward movement and the reverse movement are realized by a combination of engagement states of the respective clutches and brakes, as shown in FIG.

In FIG. 3, the circles indicate the engaged state, and the parts without the symbols indicate the released state. In particular, the low & reverse brake L & R at the first speed is used.
The fastening state indicated by the black circle of / B indicates fastening only in one range. As shown in the combination of the engagement states of the clutches and brakes shown in FIG.
When upshifting from third gear to third gear, the low clutch L /
While maintaining the fastening state of C, brake bands 2 & 4 /
At the same time when B is released, the high clutch H / C is engaged. As described above, a shift in which the engagement and disengagement of the clutch / brake (friction engagement element) is simultaneously controlled to switch the friction engagement element is referred to as a shift shift.

FIG. 4 shows the control valve section 103.
4 shows details of B. The control valve section 103B shown in FIG. 4 includes a shift valve (A) 1, a shift valve (B) 2, an accumulation control valve 3 for L / C & H / C, an accumulation control valve 4 for 2 & 4 / B, and L / C timing valve (A) 5 and L / C
Timing valve (B) 6, 2 & 4 / B timing valve (A) 7, 2 & 4 / B timing valve (B) 8
, L / C accumulator 9, 2 & 4 / B accumulator unit 10, and H / C accumulator unit 1.
1 is provided.

The shift valve (A) 1 and the shift valve (B) 2 are connected to the first and second gears according to ON / OFF of the shift solenoid (A) 21 and the shift solenoid (B) 22.
The oil path is switched according to the combination of the engagement and the release corresponding to each of the fourth speed (OD) speeds. Specifically, as shown in FIG. 5, the ON / O of the shift solenoid (A) 21 and the shift solenoid (B) 22 is previously set for each gear position.
A combination of FFs is determined. For example, at the time of an upshift from the second speed to the third speed, the shift solenoid (A)
21 is continuously turned off, and the shift solenoid (B) 22 is switched from ON to OFF.

When the shift solenoid (A) 21 and the shift solenoid (B) 22 are in the OFF state, a pair of oil passages branched from one oil passage in the shift valve (A) 1 and the shift valve (B) 2 are provided. The lower side is selected, and conversely, when the shift solenoid (A) 21 and the shift solenoid (B) 22 are in the ON state, the upper side of the pair of oil passages is selected.

Therefore, at the time of the upshift from the second speed to the third speed, the hydraulic pressure supply path to the brake band 2 & 4 / B is connected to the drain side (indicated by X in FIG. 4), while the low clutch L / The D range pressure PD supply side is connected to the hydraulic pressure supply paths of C and the high clutch H / C. L / C
& H / C accumulation control valve 3 is a solenoid pressure generated by PL duty solenoid 23.
The line pressure PL is reduced according to the size of PSOLA, and L / C
Accumulator 9 and H / C accumulator unit 1
Output the accumulation control pressure PACCMA for adjusting the back pressure of 1.

The solenoid pressure PSOLA produced by the PL duty solenoid 23 is a pressure modifier valve (P.MF.V) for regulating a modifier pressure which is a signal pressure of a line pressure PL produced by a pressure regulator valve (not shown). ). Accumulation control valve 4 for 2 & 4 / B
Is the line pressure P according to the magnitude of the solenoid pressure PSOLB generated by the 2 & 4 / B duty solenoid 24.
L is reduced, and the accumulator control pressure PACCMB for adjusting the back pressure of the 2 & 4 / B accumulator unit 10 is output.

The L / C timing valve (A) 5
L / C when the L / C timing solenoid 25 is OFF
This is a switching valve in which the signal pressure oil passage in the timing valve (B) 6 is set to the drain side, and when turned on, the signal pressure oil passage is set to the communication side. The L / C timing valve (B) 6 controls the operation of the L / C accumulator 9 when shifting up to the fourth speed or downshifting from the fourth speed, that is, at the time of shifting to release or engage the low clutch L / C. Perform back pressure control.

The 2 & 4 / B timing valve (A) 7
Is a switching valve that sets the signal pressure oil passage in the 2 & 4 / B timing valve (B) 8 to the drain side when the 2 & 4 / B timing solenoid 26 is OFF, and sets the signal pressure oil passage to the communication side when it is ON. The 2 & 4 / B timing valve (B) 8 is used when shifting up to third speed or shifting down from third speed, that is, when the brake band 2
The back pressure control of the 2 & 4 / B accumulator 10 is performed at the time of shifting for releasing or engaging & 4 / B.

The L / C accumulator 9 is guided to the back pressure chamber through an L / C timing valve (B) 6 via an L / C timing valve (B) 6 to smooth the engagement and release of the low clutch L / C. The 2 & 4 / B accumulator unit 10 has an accumulator control pressure PACC via a 2 & 4 / B timing valve (B) 8 in its back pressure chamber.
MB is guided to smooth the fastening and release of brake band 2 & 4 / B.

The 2 & 4 / B accumulator unit 10 incorporates a piston and a spring in a cylinder and sets the directions of the springs to be opposite to each other with respect to the back pressure, thereby obtaining a two-stage accumulator characteristic having different shelf pressure levels. It is composed of two accumulators 10A and 10B. In the H / C accumulator unit 11, the accumulator control pressure PACCMA is directly guided to the back pressure chamber, and the engagement and release of the high clutch H / C are smoothed.

This H / C accumulator unit 11
Also, the piston and the spring are incorporated in the cylinder and the directions of the springs are set opposite to each other with respect to the back pressure, and are constituted by two accumulators 11A and 11B which obtain two-stage accumulator characteristics having different shelf pressure levels. here,
In the shift control for automatically shifting the first to fourth speeds in the D range, a shift command is issued in accordance with a shift schedule set in advance based on the throttle opening and the vehicle speed. In accordance with the ON / OFF command of the shift solenoid for each shift speed shown in FIG.
The control is performed by issuing an ON or OFF command to the shift solenoid (A) 21 and the shift solenoid (B) 22 from the / T control unit 20.

The operation during shifting will now be described with reference to FIG. 6 taking the case of upshifting from second gear to third gear as an example. At the time of upshifting from second gear to third gear, the shift solenoid (A) 1 is operated. By turning off the shift solenoid (B) 22 from ON to OFF continuously, the D range pressure PD is continuously supplied to the low clutch L / C while the shift solenoid (B) 22 is continuously turned off. While the hydraulic pressure supply passage is drained, the D range pressure PD is supplied to the high clutch H / C which has been drained until then, and the release of the brake band 2 & 4 / B and the high clutch H
By engaging / C, the friction engagement element is switched to the engaged / released state at the third speed, and the upshift from the second speed to the third speed is performed.

When the brake band 2 & 4 / B is released with an upshift from the second speed to the third speed, the back pressure of the 2 & 4 / B accumulator unit 10 is drained by the 2 & 4 / B timing valves 7 and 8. The timing at which it is performed is controlled. FIG.
As shown in the time chart of FIG. 5, during the upshift from the second speed to the third speed, the shift solenoid (A) 1 is kept OFF continuously while the shift solenoid (B) 22
Is switched from ON to OFF, and the 2 & 4 / B timing solenoid 26 is switched from OFF to ON.

2 & 4 / B timing solenoid 26 is O
In the case of FF, the signal pressure to the 2 & 4 / B timing valve (B) 8 is drained, and the 2 & 4 / B timing valve (B) 8 is biased leftward in FIG. Accumulator unit 1
The accum control pressure PACCMB is directly guided to the back pressure chamber 0, and the drain process by the 2 & 4 / B timing valve (B) 8 is prohibited.

On the other hand, 2 & 4 / B timing solenoid 2
When the valve 6 is turned on, the 2 & 4 / B timing valve (A) 7 switches the signal pressure oil passage from the drain side to the communication side, and changes the signal pressure oil passage on the fastening side as a signal pressure acting in the direction of draining the 2 & 4 / B accumulator back pressure. The high clutch pressure PHC is supplied so that the drain processing by the pressure balance can be performed.

On the other hand, 2 & 4 / B timing valve (B)
In FIG. 8, the accumulator control pressure PACCMA on the fastening side is supplied as a signal pressure acting in the direction of supplying the 2 & 4 / B accumulator back pressure. As a result, the differential pressure ΔP between the accumulator control pressure PACCMA, which is the back pressure of the accumulator on the engagement side, and the high clutch pressure PHC, which is the operating pressure on the engagement side, becomes the set differential pressure (set by the spring load and the spool pressure receiving area). And 2 &
4 / B The spool of the timing valve (B) 8 is 2 & 4 /
The B accumulator back pressure is switched to the drain side.

When the spool of the 2 & 4 / B timing valve (B) 8 is switched to the side for draining the 2 & 4 / B accumulator back pressure, the D range pressure P as a signal pressure acting in the direction of draining the 2 & 4 / B accumulator back pressure.
D is supplied, whereby the drain state of the 2 & 4 / B accumulator back pressure is maintained. The operating pressure of the high clutch H / C, which is the engagement side, increases after the stroke of the clutch piston ends, and with the increase of the operating pressure, the first clutch pressure characteristic by the piston stroke operation of the accumulator 11B is exhibited.
The operation shifts to the second shelf pressure characteristic due to the piston stroke operation of A, and when the stroke operation by the accumulator 11A ends, the engagement pressure immediately increases to the line pressure level, and the high clutch H / C is engaged.

On the other hand, the brake bands 2 & 4 on the release side
/ B decreases from the engagement pressure based on the line pressure level to the accumulator back pressure level at once, and when the high clutch pressure PHC, which is the engagement side operating pressure, becomes the switching pressure of the 2 & 4 / B timing valve (B) 8, 2 & 4 / B. When the back pressure of the accumulator is drained, the brake band pressure P
24B drops at a large gradient, and reaches the release pressure level, and the brake bands 2 & 4 / B are released.

At the time of the release control, the solenoid pressure PSOLB previously generated by the 2 & 4 / B duty solenoid 24 is reduced from the maximum line pressure PL to the target solenoid pressure PSOLB corresponding to the input shaft torque at that time. After that, the shift solenoid (B) 22 is switched from ON to OFF to reduce the fastening pressure of the brake bands 2 & 4 / B to the accumulator back pressure level corresponding to the input shaft torque.

Similarly, when the low clutch L / C is released and the brake band 2 & 4 / B is engaged, the upshift from the third speed to the fourth speed is performed in the same manner as described above. Drain timing control of the low clutch accumulator back pressure is performed. As described above, if the drain timing of the accumulator back pressure of the disengagement side frictional engagement element is controlled, it is possible to optimally control the drain timing regardless of the variation of the frictional engagement element and the hydraulic pressure fluctuation. In particular, during the first shift after the vehicle has been left for a long time, the oil in the clutch pack is completely drained and normal hydraulic response cannot be obtained, resulting in insufficient torque capacity at the time of changing gears, causing engine idling. May be.

Therefore, in the present invention, the above-mentioned air blow is shown in FIG.
In the following, the idling suppression control will be described with reference to the time chart of FIG. The flowchart of FIG. 7 is executed at the start of the shift change. First, in step S1, the occurrence of an idling is detected.

More specifically, a detection signal (output shaft rotation speed No) of the vehicle speed sensor 107 for extracting a rotation signal from the output shaft of the automatic transmission, and a gear ratio before the gear shift (the second gear in the second gear to the third gear). Gear ratio) and the reference turbine rotation speed NtS
When the (reference input shaft rotation speed) is calculated and the actual turbine rotation speed Nt (input shaft rotation speed) detected by the turbine rotation sensor 108 becomes higher than the reference turbine rotation speed NtS + the predetermined value HYS (1). (Nt> NtS +
HYS (1)), and detects the occurrence of idling.

In the present application, the gear ratio is: gear ratio = input shaft rotation speed / output shaft rotation speed. Further, instead of detecting the occurrence of idling based on the reference turbine rotation speed NtS, the detection signal (output shaft rotation speed) of the vehicle speed sensor 107 and the turbine rotation speed Nt (input shaft rotation speed) detected by the turbine rotation sensor 108 are used. ) To calculate a gear ratio (gear ratio = input shaft rotation speed / output shaft rotation speed), and the gear ratio becomes larger than the reference gear ratio (1) set based on the gear ratio before shifting. At this time, the occurrence of the blowing may be detected.

Until the occurrence of an idling is detected in step S1, the process proceeds to step S2, and the idling flag is set to 0. On the other hand, if the occurrence of idling is detected in step S1, the routine proceeds to step S3, where 1 is set in the idling flag, and the routine proceeds to step S4, where the accumulator back pressure of the frictional engagement element on the engagement side is set in the step. The correction is performed to increase the value.

For example, during an upshift from the second speed to the third speed, the band 2 & 4 / B is released and the high clutch H / C is engaged, so that the high clutch H / C corresponds to the engagement-side friction engagement element. To control the back pressure of the high clutch H / C
The control duty of the L-duty solenoid 23 (instruction oil pressure of the accumulation control pressure PACCMA) is stepwise increased and corrected.

More specifically, the base duty corresponding to the input shaft torque and the like is corrected by a predetermined correction amount, and the correction amount depends on the engine speed and the oil temperature as shown in FIG. The correction amount is set so that the correction amount increases as the engine rotation speed decreases and the oil temperature decreases. In the present embodiment, the oil pump that supplies the hydraulic oil is driven by the engine, and the lower the engine speed, the smaller the discharge amount of the oil pump.Therefore, the lower the engine speed, the larger the correction amount. The fastening-side accumulator back pressure is increased so that the torque capacity of the fastening-side frictional engagement element is rapidly increased.

When the temperature of the hydraulic oil is low, the hydraulic response is slow. Therefore, the correction amount is increased as the oil temperature is low, so that the torque capacity of the engagement side frictional engagement element is rapidly increased. is there. In step S5, it is determined whether or not 1 is set in the blowing flag.

When 1 is set in the idling flag, the process proceeds to step S6, and it is determined whether or not the idling has converged. This convergence of the blowing is determined by the turbine rotation speed Nt.
When the differential value of the deviation from the reference turbine rotation speed Nts becomes smaller than a predetermined value HYS (2) (for example, 0) (d / dt (Nt-Nts) <HYS (2)), A configuration for detecting convergence may be employed.

According to this, when the turbine rotation speed Nt changes from a tendency to deviate from the reference turbine rotation speed NtS to a tendency to return toward the reference turbine rotation speed NtS, it is possible to detect the convergence of the blowing. Further, a gear ratio (gear ratio = input shaft rotation speed Nt / output shaft rotation speed N) is determined from the detection signal No of the vehicle speed sensor 107 and the turbine rotation speed Nt detected by the turbine rotation sensor 108.
o) is calculated, and when the gear ratio becomes smaller than the reference gear ratio (2) set based on the gear ratio in the second speed before the gear shift, the convergence of the airflow is detected. good.

Further, when Nt <NtS + HYS (2), the convergence of the blowing may be determined. In addition, if the convergence of the blowing is detected based on the differential value of the difference between the turbine rotation speed Nt and the reference turbine rotation speed NtS, the time when the blowing is reversed to the convergence tendency can be detected with good response, and It is possible to make the convergence of the air blow in a short time while avoiding the unnecessary correction, which is more preferable than the configuration in which the convergence of the air blow is detected based on the gear ratio.

When the convergence of the blowing is detected in step S6, the process proceeds to step S7, and the stepwise increase correction of the accumulator back pressure of the frictional engagement element on the engagement side is stopped. For example, when shifting from the second gear to the third gear, the increase correction of the control duty of the PL duty solenoid 23 that controls the accumulator back pressure of the high clutch H / C on the engagement side is stopped, and the base duty is returned.

When the occurrence of the idling is detected as described above, if the accumulator back pressure of the engagement-side friction engagement element is increased stepwise, the engagement pressure (torque capacity) of the engagement-side friction engagement element is increased. Can be increased with good response, and the blowing can be surely converged in a short time. Further, overshooting is performed by setting an increase correction amount of the accumulator back pressure of the engagement-side friction engagement element in accordance with an engine rotation speed correlated with a discharge amount of the oil pump and an oil temperature indicating viscosity of hydraulic oil. Without this, the engagement pressure (torque capacity) of the engagement-side frictional engagement element can be increased sufficiently for convergence of the idling.

Since it is presumed that the occurrence of idling is mainly caused by a delay in the hydraulic response of the engagement-side frictional engagement element, precharging is performed on the engagement-side frictional engagement element. Preferably, the precharge control will be described with reference to the flowchart of FIG. In the flowchart of FIG. 9, in step S11, the start of the shift change is determined, and when the shift change is started, the process proceeds to step S12.

In step S12, a precharge time TIM1 is set according to the engine speed and the oil temperature.
As shown in FIG. 10, the precharge time TIM1 is set to be longer as the engine speed is lower and the oil temperature is lower. This is because, similarly to the setting characteristic of the correction amount, the lower the engine speed, the smaller the discharge amount of the oil pump, and the lower the temperature of the hydraulic oil, the lower the hydraulic response.

In step S13, a timer for measuring the time elapsed since the start of the shift change is counted up. In step S14, it is determined whether or not the time measured by the timer is shorter than the precharge time TIM1. . If the time measured by the timer is shorter than the precharge time TIM1, the process proceeds to step S15, and precharge is performed on the frictional engagement element on the engagement side.

The precharging is performed by increasing the back pressure of the accumulator on the fastening side to the maximum pressure. Specifically, the precharge is performed by correcting the control duty of the PL duty solenoid 23 or 2 & 4 / B duty solenoid 24.
The accumulation control pressure PACCM is set to the maximum line pressure PL. Then, if the precharge for setting the accumulator back pressure of the engagement side frictional engagement element to the maximum pressure is continued for the precharge time TIM1, the process proceeds from step S14 to step S16, where the precharge is stopped and the engagement side frictional engagement is stopped. The accumulator back pressure of the element is returned to a value (base duty) corresponding to the input shaft torque.

[Brief description of the drawings]

FIG. 1 is a system diagram showing a vehicle drive system according to an embodiment.

FIG. 2 is a skeleton diagram showing a transmission mechanism in the embodiment.

FIG. 3 is a diagram showing combinations of engagement states of frictional engagement elements at each shift speed in the embodiment.

FIG. 4 is a hydraulic circuit diagram showing a control valve unit in the embodiment.

FIG. 5 is a diagram showing a combination of ON / OFF of shift solenoids A and B at each shift speed in the embodiment.

FIG. 6 is a time chart showing control at the time of a second-speed to third-speed upshift in the embodiment.

FIG. 7 is a flowchart showing idling control at the time of a shift change in the embodiment.

FIG. 8 is a diagram showing characteristics of a correction amount of a back pressure control amount in the embodiment.

FIG. 9 is a flowchart illustrating engagement-side precharge control during a shift change according to the embodiment.

FIG. 10 is a diagram showing characteristics of a precharge time in the precharge control.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Shift solenoid (A) 2 ... Shift solenoid (B) 3 ... Accum control valve for L / C & H / C 4 ... Accum control valve for 2 & 4 / B 5 ... L / C timing valve (A) 6 ... L / C timing Valve (B) 7 ... 2 & 4 / B timing valve (A) 8 ... 2 & 4 / B timing valve (B) 9 ... L / C accumulator 10 ... 2 & 4 / B accumulator unit 11 ... H / C accumulator unit 21 ... Shift solenoid (A) 22: shift solenoid (B) 23: PL duty solenoid 24: 2 & 4 / B duty solenoid 25: L / C timing solenoid 26: 2 & 4 / B timing solenoid 101: engine 102: torque converter 103: automatic transmission 103A: transmission mechanism Part 103B ... Troll valve unit 104: A / T controller 105: A / T oil temperature sensor 106: accelerator opening sensor 107: vehicle speed sensor 108: turbine rotation sensor 109: engine rotation sensor G1, G2: planetary gear H / C: high clutch R /C...reverse clutch L / C ... low clutch 2 & 4 / B ... brake band L & R / B ... low & reverse brake L / OWC ... one-way clutch

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Claims (6)

[Claims] An automatic transmission configured to perform a shift by changing a friction engagement element that simultaneously performs engagement control and release control of two different friction engagement elements while controlling a back pressure of an accumulator. A control device for an automatic transmission, wherein an accumulator back pressure of a frictional engagement element on a fastening side is increased in a stepwise manner when an engine idling is detected during gear shifting. 2. The method according to claim 1, wherein the stepwise increase correction amount of the accumulator back pressure is determined according to at least one of an engine speed and a temperature of hydraulic oil.
A control device for an automatic transmission according to the above. 3. A structure in which the accumulator back pressure of the frictional engagement element on the engagement side is controlled to the maximum hydraulic pressure for a predetermined period from the start of gear shifting, while the predetermined period is controlled by at least one of the engine speed and the temperature of the hydraulic oil. 3. The control device for an automatic transmission according to claim 1, wherein the control device is determined according to the condition. 4. The occurrence of the idling is detected in accordance with a deviation between an input shaft rotation speed of a transmission mechanism and a reference input shaft rotation speed calculated from an output shaft rotation speed of the transmission mechanism and a gear ratio before shifting. The control device for an automatic transmission according to any one of claims 1 to 3, wherein: 5. The method according to claim 5, wherein the convergence of the idling is calculated as a differential value of a deviation between an input shaft rotation speed of the transmission mechanism and a reference input shaft rotation speed calculated from an output shaft rotation speed of the transmission mechanism and a gear ratio before gear shifting. The control device for an automatic transmission according to any one of claims 1 to 4, wherein the detection is performed based on the control information. 6. The method according to claim 1, wherein the occurrence and convergence of the idling are detected based on a comparison between a gear ratio calculated from an input shaft rotation speed and an output shaft rotation speed of a transmission mechanism and a predetermined value. The control device for an automatic transmission according to any one of claims 1 to 3.