JP2002089697A - Variable speed control device for automatic transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent occurrence of torque fluctuation at the time of down-shift when an accelerator is actuated from the coasting state in an automatic transmission for performing shifting by switching friction engagement elements. SOLUTION: When a down-shift caused by actuating the accelerator is requested, according to the comparison between an input shaft torque of the transmission and a designated value and the comparison between the engine speed and the turbine rotating speed, it is discriminated whether it is in the coasting state or in the running state where the driving force of an engine is applied, and if it is in the coasting state, the start of release control is delayed until the transition to the running state where the driving force of the engine is applied is caused.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shift control device for an automatic transmission configured to shift by changing a friction engagement element, and more particularly to a shift control at the time of a downshift accompanying depression of an accelerator.

[0002]

2. Description of the Related Art Conventionally, there has been known a shift control device of an automatic transmission configured to shift by changing a friction engagement element that simultaneously performs engagement control and release control of two different friction engagement elements. (See JP-A-6-341526 and JP-A-9-133205).

[0003]

By the way, when the accelerator is depressed from the coasting state (coast state) of the vehicle and a downshift request is generated in accordance with the depressing operation, the frictional engagement element is normally operated. When the release control is started, the release control is performed in a state where the gear fluctuates between the coast side and the apply side due to gear backlash during a transition from a coasting state to a state where driving force is applied. Therefore, unexpected large torque fluctuation may occur.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and it is an object of the present invention to provide a shift control for an automatic transmission capable of avoiding a large torque fluctuation even during a downshift caused by depressing an accelerator from a coasting state. It is intended to provide a device.

[0005]

Therefore, the invention according to claim 1 is configured to delay the start of the release control by a predetermined period when a downshift is requested due to depression of the accelerator. According to this configuration, when a downshift (hereinafter, also referred to as power-on-down) is requested due to depression of the accelerator, the start of the release control of the friction engagement element is delayed from the normal start timing, and the driving state corresponding to the depression of the accelerator is depressed. After that, release control is started.

According to the second aspect of the present invention, the release control is started when a downshift is requested due to depression of the accelerator and the vehicle is in a coasting state when the downshift is requested. Is delayed by a predetermined period. According to such a configuration, at the time of the power-on-down request, and when the request is generated and the vehicle is in the coasting state (coast state), the release control of the friction engagement element is started for a predetermined period. The release control is started by avoiding the transition from the coasting state (coast state) to the running state to which the driving force of the engine is applied.

According to a third aspect of the present invention, the predetermined period for delaying the start of the release control is a period from the coasting state to the driving state to which the driving force is applied. According to this configuration, the accelerator is depressed from the coasting traveling state (coast state), and the frictional engagement is performed after a response period elapses until the driving state is switched to the driving state to which the driving force of the engine is applied in accordance with the depression operation of the accelerator. The release control of the element is started, and the release control is started not in the coasting running state but in the running state where the driving force is applied.

According to a fourth aspect of the present invention, the predetermined period for delaying the start of the release control is a period until the change in the engine operating state accompanying the depression of the accelerator reaches a predetermined value. According to this configuration, the operation state of the engine changes with the depression of the accelerator, and the start of the release control of the friction engagement element is delayed until the operation state reaches a predetermined value.

According to a fifth aspect of the present invention, a period until the change in the engine operating state reaches a predetermined value is a period until the rotation speed of the engine reaches a predetermined value. According to this configuration, the start of the release control of the friction engagement element is delayed until the engine rotation speed increases and reaches a predetermined value with the depression of the accelerator, and the release control is started when the engine rotation speed reaches the predetermined value. To start.

According to a sixth aspect of the present invention, a period until the change in the engine operating state reaches a predetermined value is a period until the input shaft torque of the automatic transmission reaches a predetermined value. According to this configuration, the torque generated by the engine increases with the depression of the accelerator, and the input shaft torque of the automatic transmission changes accordingly, and the release control of the friction engagement element is started until the torque reaches a predetermined value. And release control is started when the input shaft torque reaches a predetermined value.

[0011] In the invention according to the seventh aspect, the discrimination between the coasting traveling state and the traveling state to which the driving force is applied is made based on the input shaft torque of the automatic transmission. According to this configuration, the coasting traveling state and the traveling state to which the driving force is applied are determined based on whether the input shaft torque of the automatic transmission is greater than a predetermined value. The invention according to claim 8 is configured to determine the coasting traveling state and the traveling state to which the driving force is applied based on a comparison between the rotation speed of the engine and the rotation speed of the input shaft of the automatic transmission.

According to this configuration, in a configuration in which the engine driving force is transmitted through the torque converter, in a state where the engine output torque is transmitted to the automatic transmission,
The rotational speed on the engine side becomes higher with the torque converter interposed, and conversely, during coasting when the engine is driven from the drive wheel side, the rotational speed on the transmission side becomes higher with the torque converter interposed therebetween. Thus, a coasting traveling state and a traveling state to which a driving force is applied are determined.

[0013]

According to the first aspect of the present invention, the start of release control is delayed when a power-on-down request is made,
The release control can be started while avoiding a transition period until the operating state is commensurate with the depression of the accelerator, and there is an effect that a large torque fluctuation can be avoided by performing the release control in the transition period. .

According to the second aspect of the present invention, when a power-on / down request is made from the coasting state, the release control can be started while avoiding a transition from the coasting state to the traveling state to which the driving force of the engine is applied. Thus, there is an effect that it is possible to avoid a large torque fluctuation during the shift control. According to the third aspect of the present invention, the release control is started after switching from the coasting running state to the running state to which the driving force of the engine is applied, so that the start of the release control is not excessively delayed and a large torque fluctuation is caused. This has the effect that it is possible to reliably avoid inducing.

According to the inventions described in claims 4 to 6, the transition period until the operating state is commensurate with the depression of the accelerator is accurately determined from changes in the engine operating state such as the engine speed and the input shaft torque of the transmission. It has the effect of being able to judge. According to the invention of claim 7, there is an effect that the coasting traveling state and the traveling state to which the driving force of the engine is applied can be accurately determined based on the input shaft torque of the transmission.

According to the present invention, the coasting state and the running state to which the driving force of the engine is applied can be accurately determined from the correlation between the engine speed and the input shaft speed of the transmission. is there.

[0017]

Embodiments of the present invention will be described below. FIG. 1 shows a transmission mechanism of an automatic transmission according to an embodiment, in which an output of an engine is transmitted to a transmission mechanism 2 via a torque converter 1.

The transmission mechanism 2 includes two sets of planetary gears G1,
G2, 3 sets of multiple disc clutches H / C, R / C, L / C, 1
A set of brake bands 2 & 4 / B, a set of multiple disc brakes L & R / B, and a 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 is configured to be connectable to the input shaft IN by a reverse clutch R / C, and is configured to be fixable by a brake band 2 & 4 / B. Sun gear S2 of the planetary gear set G2
Are directly connected to the input shaft IN. The carrier c1 of the planetary gear set G1 is configured to be connectable to the input shaft I by a high clutch H / C, while the ring gear r2 of the planetary gear set G2 is connected to the planetary gear set G1 by a low clutch L / C.
And the carrier c1 of the planetary gear set G1 can be fixed by the 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 2 having the above-described configuration, the first to fourth speeds and the reverse are realized by a combination of engagement states of the clutches and brakes, as shown in FIG. In FIG. 2, a circle indicates the engaged state, and a part without a symbol indicates the open state. In particular, the engaged state indicated by a black circle of the low & reverse brake L & R / B at the first speed. Indicates the fastening only in one range.

According to the combination of the engaged states of the clutches and brakes shown in FIG. 2, for example, during a downshift from the fourth speed to the third speed, the brake bands 2 & 4 / B are released and the low clutch L / C is engaged. During the downshift from the third speed to the second speed, the high clutch H / C is released and the brake bands 2 & 4 / B are engaged. At the time of the upshift from the second speed to the third speed,
The brake bands 2 & 4 / B are released and the high clutch H / C is engaged. At the time of the upshift from the third speed to the fourth speed, the low clutch L / C is released and the brake bands 2 & 4 / B are engaged. Will be.

As described above, the shift in which the engagement control and the release control of the clutch / brake (friction engagement element) are simultaneously controlled to change the friction engagement element is referred to as a shift change. Each of the clutches and brakes (friction engagement elements) is operated by a supply hydraulic pressure.
The supply hydraulic pressure for each clutch / brake is adjusted by various solenoid valves included in the solenoid valve unit 11 shown in FIG.

An A / T controller 12 for controlling various solenoid valves of the solenoid valve unit 11 includes an A / T oil temperature sensor 13, an accelerator opening sensor 14,
Detection signals from the vehicle speed sensor 15, the turbine rotation sensor 16, the engine rotation sensor 17, the air flow meter 18, and the like are input, and the engagement hydraulic pressure in each friction engagement element is controlled based on the detection results.

In FIG. 3, reference numeral 20 denotes an engine combined with the automatic transmission. Here, the state of the shift change control at the time of a downshift (hereinafter, referred to as power-on-down) due to the depression of the accelerator,
The description will be given in accordance with the flowcharts of FIGS. 5 to 17 while referring to the time chart of FIG.

The flowchart of FIG. 5 shows a main control routine common to the engagement-side friction engagement element and the release-side friction engagement element. In step S1, it is determined whether a power-on-down request has occurred. A / T controller 12
A shift map in which the shift speed is set in accordance with the vehicle speed VSP and the accelerator opening (throttle opening) is stored in advance, for example, the current shift speed (before shifting) and the shift speed searched from the shift map. The state in which the gear is different from the gear and is in the downshift direction and the accelerator is not fully closed is determined as a power-on-down shift request.

When a power-on-down shift request is determined, the process proceeds to step S2, where the ratio is calculated as the ratio between the input shaft rotation speed (turbine rotation speed) and the output shaft rotation speed (vehicle speed) of the transmission mechanism. It is determined whether or not the gear ratio (gear ratio = input shaft rotation speed / output shaft rotation speed) is higher than a feedback (F / B) start gear ratio set based on the gear ratio before shifting.

The determination as to whether the gear ratio is higher than the F / B start gear ratio is to determine the start of the change in the gear ratio due to slippage of the disengagement side frictional engagement element. B
The start gear ratio is set as a gear ratio slightly higher than the gear ratio before the gear change. When the gear ratio is equal to or less than the F / B start gear ratio (from the time when the power-on-down shift request is issued until the gear ratio becomes the F / B start gear ratio),
The preparation phase process of step S3 is executed.

The preparation phase process in step S3 includes:
The release-side preparation phase process is divided into the release-side process and the engagement-side process, and is shown in the flowcharts of FIGS. The flowchart of FIG. 6 shows a main routine of a preparation phase process of a disengagement side (for high speed) frictional engagement element. In step S31, the vehicle coasts when a power-on-down shift request is issued. It is determined whether the vehicle is in a state (coast state) or in a running state to which an engine driving force is applied (hereinafter, referred to as an engine driving state).

If it is determined in step S31 that the engine has been driven when the power-on / down shift request is issued, the flow jumps to step S33 to determine the start of release control. On the other hand, if it is determined in step S31 that the vehicle is in the coasting state at the time when the power-on-down shift request is issued, the process proceeds to step S32.

In step S32, it is determined whether or not the state has been switched from the coasting running state to the engine driving state, and the determination in step S32 is repeated until the state is switched to the engine driving state. Proceed to and determine the start of release control. Therefore, when the vehicle is in the coasting state when the power-on-down shift request is issued, the start of the release control is delayed until the vehicle is switched to the engine driving state.

The discrimination between the coasting state and the engine driving state in steps S31 and S32 is performed as shown in the flowchart of FIG. In the flowchart of FIG. 7, in step S311, it is determined whether or not the input shaft torque of the transmission is smaller than a predetermined value. If it is determined in step S311 that the input shaft torque of the transmission is smaller than the predetermined value, the process proceeds to step S31.
Proceeding to 2, it is determined that the vehicle is coasting.

On the other hand, if it is determined in step S311 that the input shaft torque of the transmission is equal to or greater than the predetermined value, the flow proceeds to step S311.
Proceeding to 313, the engine drive state is determined. The input shaft torque of the transmission mechanism may be detected by a sensor, but can be estimated from operating conditions. For example, the output torque of the engine estimated from the intake air amount, the engine speed, etc. It can be estimated from the torque ratio.

As described above, in the case of determining the coasting state and the engine driving state based on the input shaft torque, the input shaft torque becomes smaller than a predetermined value when a power-on-down shift request is issued. If it is smaller, the start of the release control will be delayed until the input shaft torque reaches a predetermined value. Further, the determination of the coasting state and the engine driving state in steps S31 and S32 may be performed as shown in the flowchart of FIG.

In the flowchart of FIG. 8, step S321 determines whether or not the engine speed is lower than the turbine speed (input shaft speed of the transmission) + a predetermined value HYS. When it is determined in step S321 that the engine rotation speed is smaller than the turbine rotation speed + predetermined value HYS, the process proceeds to step S322.
It is determined that the vehicle is coasting.

On the other hand, if it is determined in step S321 that the engine speed is equal to or higher than the turbine speed + predetermined value HYS, the flow advances to step S323 to determine the engine driving state. As described above, in a configuration in which the coasting state and the engine driving state are determined based on a comparison between the engine rotation speed and the turbine rotation speed, the engine rotation is performed at the time when the power-on / down shift request is issued. If the speed is lower than the turbine rotation speed + predetermined value HYS, the start of the release control is delayed until the engine rotation speed reaches the turbine rotation speed + predetermined value HYS.

Since the vehicle was in the coasting state when the power-on-down shift request was issued, even if the process proceeds to the delay processing of step S32, the state shifts to the engine driving state after a predetermined time has elapsed. When the determination has not been made, it is preferable to forcibly start the release control. If the release control is started immediately as usual while the vehicle is in the coasting state at the time of the power-on-down shift request, the gears will backlash during the transition from the coasting state to the engine drive state, and The release control is performed in a state in which the torque fluctuates between the coast side and the apply side, and an unexpected large torque fluctuation may occur.

On the other hand, as described above, if release control is started after switching to the engine drive state,
Release control can be performed without being affected by gear backlash, and large torque fluctuations can be avoided. After performing the delay processing, if the start of the release control is determined in step S33, the process proceeds to step S3.
After step 4, a preparation phase process, which is the first process of the release control, is executed.

In step S34, a predetermined time TIMER
It is determined whether only one has elapsed from the release control start determination. If it is within the predetermined time TIMER1, the process proceeds to step S35 to calculate the release initial oil pressure. The calculation of the initial disengagement hydraulic pressure in step S35 is shown in detail in the flowchart of FIG. 9. In step S351, the non-shift-time hydraulic pressure Po0 and the disengagement initial hydraulic pressure Po1 of the friction engagement element for performing the release control are calculated.

The non-shifting oil pressure Po0 is calculated as Po0 = K1 × (Tt × Tr-o × room allowance (0)) + Prtn-o. Here, K1 is a coefficient for converting the transmission torque capacity of the disengagement side frictional engagement element into hydraulic pressure.

Tt is an estimated value of the input shaft torque of the speed change mechanism, and is estimated from, for example, the output torque of the engine estimated from the intake air amount and the engine speed, and the torque ratio of the torque converter. Tr-o is a critical torque ratio for obtaining a critical transmission torque capacity at which the friction engagement element causes slippage with respect to the input shaft torque Tt.

The allowance (0) is a correction coefficient for adding a marginal torque capacity to the critical transmission torque capacity, and is stored in advance as a value of, for example, about 3.0. P
rtn-o is a release-side standby pressure (release-side return spring pressure) and is stored in advance for each friction engagement element.
On the other hand, the release initial oil pressure Po1 is calculated as Po1 = K1 × (Tt × Tr-o × room allowance (1)) + Prtn-o.

That is, only the margin is different from the arithmetic expression of the non-shift-time hydraulic pressure Po0, and the arithmetic expression of the release initial hydraulic pressure Po1 uses a relatively low value of the allowance (1) of about 1.2. . At the time of non-shift, it is controlled to the non-shift hydraulic pressure Po0, but when releasing in response to a shift request, the hydraulic pressure is reduced from the non-shift hydraulic pressure Po0 to the release initial hydraulic pressure Po1 within the predetermined time TIMER1. In step S352, the hydraulic pressure gradient Rmp-Po1 within the predetermined time TIMER1 is calculated as Rmp-Po1 = (Po0-Po1) / TIMER1.

Then, the hydraulic pressure is reduced by (Rmp-Po1) every unit time from the non-shifting hydraulic pressure Po0, and is reduced to the release initial hydraulic pressure Po1 when a predetermined time TIMER1 has elapsed. As described above, the predetermined time TI
After the pressure is reduced to the release initial oil pressure Po1 until MER1 elapses, and until the gear ratio is determined to be higher than the F / B start gear ratio in step S36, step S37 is performed. Is executed.

The details of the sharing ratio ramp control in step S37 are shown in the flowchart of FIG. 10. In step S371, the release initial oil pressure Po1 and the release oil pressure Po2 are calculated. The release hydraulic pressure Po2
Is calculated as Po2 = K1 × (Tt × Tr−o × room allowance (2)) + Prtn-o, and the margin allowance (2) is 1.0.
Use a smaller value, for example, about 0.8 (Margin (0)>
Extra room (1)>0> extra room (2)).

In step S372, a predetermined time TIME
In R2, the release hydraulic pressure Po1 is changed to the release hydraulic pressure Po2.
The oil pressure ramp gradient (the oil pressure decrease width per unit time) for decreasing the pressure is calculated as Rmp-Po2 = (Po1-Po2) / TIMER2.

If the gear ratio is not higher than the F / B start gear ratio within the predetermined time TIMER2 from the time when the predetermined time TIMER1 has elapsed, the hydraulic pressure is increased by (Rmp-Po2) every unit time. Decrease. On the other hand, the preparation phase process on the fastening side is shown in the flowchart of FIG. The flowchart of FIG. 11 shows a routine of a preparation phase process on the engagement side (for the low speed stage). In step S41, a predetermined time T from the shift determination is determined.
It is determined whether or not only IMER0 has elapsed.

If it is determined in step S41 that the predetermined time TIMER0 has not elapsed since the shift determination,
Proceeding to step S42, hydraulic pressure precharge for the engagement-side friction engagement element is performed. The hydraulic pressure precharge processing is performed by setting a predetermined precharge pressure to the predetermined time TIME.
This is a process of continuously outputting only R0. If the start of the release-side preparation phase processing (start of release control) is not delayed, the precharge processing and the release control are started at the same time. In the case of delaying, as shown in FIG. 4, release control is started with a delay after the start of precharge.

When the predetermined time TIMER0 has elapsed,
In step S43, the gear ratio is set to a predetermined engagement start gear ratio (1).
Then, while the gear ratio is equal to or less than the engagement start gear ratio (1), the process proceeds to step S44, and the standby pressure Prtn- stored in advance for each friction engagement element is determined.
A standby pressure process for performing the output of c is performed. Here, returning to the flowchart of FIG. 5 described above, if it is determined in step S2 that the gear ratio has become larger than the F / B start gear ratio, the process proceeds from step S2 to step S4, where the gear ratio is It is determined whether or not the F / B end gear ratio is slightly larger than the gear ratio after the shift.

If it is determined that the gear ratio is larger than the F / B start gear ratio but is equal to or smaller than the F / B end gear ratio, an inertia phase process in step S5 is executed. The inertia phase process for the release side is shown in the flowchart of FIG.

The flowchart of FIG. 12 shows the main routine of the release-side inertia phase process. In step S51, basic control of the release-side hydraulic pressure is performed. In the basic control, the release-side command oil pressure Po3 is calculated as follows: Po3 = K1 × (Tt−Tinr × HOSEI− _VSP ) × Tr−o + P
Calculated as rtn-o.

Here, Tinr is an inertia torque associated with an increase in rotation due to power on / down, and is stored in advance in a table corresponding to the target shift time. HOSEI- _VSP is an inertia torque correction coefficient stored in advance in a table corresponding to the vehicle speed VSP. In step S52, the turbine rotation (rpm) is subjected to turbine rotation feedback control for matching the turbine rotation (rpm) to the target turbine rotation according to the elapsed time from the start of the shift, using the release-side instruction hydraulic pressure Po3 as a basic value.

More specifically, a target gear ratio is set in accordance with the elapsed time from the start of gear shifting, and a target turbine rotation is calculated from the target gear ratio and the output shaft rotation (vehicle speed VSP). Then, from the deviation between the actual turbine rotation and the target turbine rotation, for example, proportional / integral / differential control (PID control)
The release-side command hydraulic pressure Po3 is corrected by the feedback correction amount.

On the other hand, the inertia phase process on the fastening side is shown in the flowchart of FIG. In the flowchart of FIG. 13, in step S61, it is determined whether the gear ratio has exceeded the engagement start gear ratio (1). Until the gear ratio exceeds the engagement start gear ratio (1), the process proceeds to step S62, and the standby in the preparation phase is performed. Subsequent to the pressure control, standby pressure control for maintaining the engagement side hydraulic pressure at the standby pressure Prtn-c is performed.

If it is determined in step S61 that the gear ratio has exceeded the engagement start gear ratio (1), then in step S63 the gear ratio exceeds the engagement start gear ratio (2) (> the engagement start gear ratio (1)). Is determined. Then, during a period from the time when the gear ratio exceeds the engagement start gear ratio (1) to the time when the gear ratio exceeds the engagement start gear ratio (2), the process proceeds to step S64, and the changeover preparation control as the preparation for the changeover control in the torque phase is performed. Do.

In the changeover preparation control, the inertia torque Tinr and the correction coefficient HOSEI- _VSP of the inertia torque Tinr according to the vehicle speed are set in the same manner as in the release side control, and the hydraulic pressure equivalent to the inertia torque is set as follows. calculate. Hydraulic oil equivalent to inertia torque = Tr-o x Tinr x HOSEI- _VSP
× K1 + Prtn-c Here, Prtn-c is the standby pressure on the fastening side.

During the period from the engagement start gear ratio (1) to the engagement start gear ratio (2), the standby pressure Prtn-
The pressure is increased from c to the hydraulic pressure equivalent to the inertia torque.
If the engagement start gear ratio (2) is exceeded, the process proceeds to step S66 when the time is within the predetermined time TIMER3 determined in step S65, and the changeover control is executed. In the changeover control, first, a ramp Rmp-Tr (1) for increasing the hydraulic pressure on the engagement side with time is stored in advance in accordance with the elapsed time after exceeding the engagement start gear ratio (2). Search from a table.

Then, the engagement-side command pressure Pc1 is calculated from the ramp Rmp-Tr (1), the inertia torque Tinr, the estimated input torque Tt, and the like according to the following equation. Pc1 = K2 × Tt × Tr-c × Rmp-Tr (1) + Tr-o × Tin
r × HOSEI- _VSP × K1 + Prtn-c In the above equation, K2 is a conversion coefficient for converting the transmission torque capacity on the engagement side into hydraulic pressure, Tt is an estimated input shaft torque, Tt is
rc is a critical torque ratio set for each frictional engagement element on the engagement side, and a minimum hydraulic pressure (critical transmission torque capacity) on the engagement side capable of transmitting the input torque at that time is obtained from K2 × Tt × Tr-c. Rara.

Here, the lamp Rmp-Tr (1) is initially 0
Then, after a predetermined time TIMER3 has elapsed, it rises to 1
K2 × Tt × Tr-c × Rmp-Tr (1) is initially 0,
After the elapse of the fixed time TIMER3, K2 × Tt × Tr-c is obtained.
You. Also, Tr-o x Tinr x HOSEI-_{V SP}× K1 + Prtn-c
Is the hydraulic pressure equivalent to the inertia torque,
For a predetermined time TIMER
Within 3, the oil pressure is increased and changed by K2 × Tt × Tr-c.

If the gear ratio exceeds the F / B end gear ratio, the process proceeds from step S4 to step S6 in the flowchart of FIG. 5, and a predetermined time TIMER4 has elapsed since the F / B end gear ratio was exceeded, and The predetermined time TI
It is determined whether or not a predetermined time TIMER5 has elapsed from the time when MER3 has elapsed. If any one of them has not elapsed, the process proceeds to step S7 to execute a torque phase process.

The torque phase process on the release side is shown in the flowchart of FIG.
Then, the ramp control for reducing the oil pressure on the release side to 0 at the predetermined time TIMER4 is executed. Specifically, the release side hydraulic pressure at the time when the gear ratio exceeds the F / B end gear ratio
Based on Po5 and the predetermined time TIMER4, a decrease gradient Rmp-Po3 of the hydraulic pressure is calculated as Rmp-Po3 = (Po5-0) / TIMER4, and the hydraulic pressure is reduced by the Rmp-Po3 per unit time.

On the other hand, the torque phase process on the fastening side is shown in the flowchart of FIG. In the flowchart of FIG. 15, in a step S81, it is determined whether or not a predetermined time TIMER3 has elapsed since the gear ratio exceeded the engagement start gear ratio (2). And the predetermined time TI
If MER3 has not elapsed, the process proceeds to step S82, and the switching control is continued following the process in the inertia phase.

In step S81, the predetermined time TIMER
If it is determined that 3 has elapsed, step S8
Then, it is determined whether or not a predetermined time TIMER5 has elapsed from the time when the predetermined time TIMER3 has elapsed. If the time is within the predetermined time TIMER5, the flow proceeds to step S84 to execute shelf pressure control.

In the shelf pressure control, first, the torque sharing ratio of the engagement-side friction engagement element after the shift is set, and then the engagement-side command pressure Pc2 is calculated according to the following equation. Pc2 = K2 × Tt × Tr-c + Tr-o × Tinr × HOSEI- _VSP
× K1 + Prtn-c When the predetermined time TIMER4 has elapsed after exceeding the F / B end gear ratio, and further when the predetermined time TIMER5 has elapsed since the predetermined time TIMER3 has elapsed, in the flowchart of FIG. S
7 and after a predetermined time TIMER5 has elapsed,
It is determined whether a predetermined time TIMER6 has elapsed.

If the predetermined time TIMER6 has not elapsed, an end phase process in step S9 is executed. The release-side end phase process is shown in the flowchart of FIG. 16. In step S901, a process of maintaining the release-side hydraulic pressure (= 0) at the end of the torque phase is performed.

On the other hand, the termination phase process on the fastening side is shown in FIG.
7 is shown in the flowchart. In the flowchart of FIG. 17, in step S91, if it is determined that the predetermined time TIMER6 has not elapsed since the shift to the end phase process, the process proceeds to step S92 to execute the end phase process on the fastening side. In the termination phase process on the engagement side, first, the ramp Rmp- which increases the transmission torque capacity of the friction engagement element on the engagement side from the value (critical pressure) at the end of the torque phase to, for example, 1.2 times in the predetermined time TIMER6. Set Tr (2).

Then, based on the ramp Rmp-Tr (2), the command pressure on the fastening side is calculated according to the following equation. Pc3 = K2 × Tt × Tr-c × (1 + 0.2 × Rmp-Tr
(2)) + Tr-o × Tinr × HOSEI- _VSP × K1 + Prtn-c During the predetermined time TIMER6, the hydraulic pressure is increased to about 1.2 times the critical pressure by controlling the pressure to the command pressure Pc3 calculated by the above equation. Is the predetermined time TIMER
At the time when 6 has elapsed, the hydraulic pressure is increased stepwise to the maximum pressure.

If the start of the release control is delayed until switching to the engine drive state when the vehicle is in the coasting state when the power downshift request is generated, the details of the release control and the engagement control in the shift change may be described. It is not limited to the above. Further, simply, when a power-on downshift request is generated, the start of the release control may always be delayed by a fixed time without determining whether the vehicle is in the coasting state.

[Brief description of the drawings]

FIG. 1 is a diagram showing a transmission mechanism of an automatic transmission according to an embodiment.

FIG. 2 is a diagram showing a correlation between a combination of engagement states of frictional engagement elements in the transmission mechanism and a shift speed.

FIG. 3 is a system diagram showing a control system of the automatic transmission.

FIG. 4 is a time chart showing a state of shifting by changing a friction engagement element in the embodiment.

FIG. 5 is a flowchart showing a state of a shift change control of a friction engagement element in the embodiment.

FIG. 6 is a flowchart illustrating a preparation phase process of a disengagement-side friction engagement element.

FIG. 7 is a flowchart showing a process for determining a coasting state and an engine driving state.

FIG. 8 is a flowchart showing a process of determining a coasting state and an engine driving state.

FIG. 9 is a flowchart showing a preparation phase process of a release-side friction engagement element.

FIG. 10 is a flowchart showing a preparation phase process of a release-side friction engagement element.

FIG. 11 is a flowchart illustrating a preparation phase process of a fastening-side friction engagement element.

FIG. 12 is a flowchart showing inertia phase processing of a disengagement-side friction engagement element.

FIG. 13 is a flowchart showing an inertia phase process of the engagement-side friction engagement element.

FIG. 14 is a flowchart showing a torque phase process of a disengagement side frictional engagement element.

FIG. 15 is a flowchart showing a torque phase process of the engagement-side friction engagement element.

FIG. 16 is a flowchart showing a termination phase process of a disengagement-side friction engagement element.

FIG. 17 is a flowchart showing a termination phase process of the engagement-side friction engagement element.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Torque converter 2 ... Transmission mechanism 11 ... Solenoid valve unit 12 ... A / T controller 13 ... A / T oil temperature sensor 14 ... Accelerator opening degree sensor 15 ... Vehicle speed sensor 16 ... Turbine rotation sensor 17 ... Engine rotation sensor 18 ... Air flow Meter 20: Engine G1, G2: Planetary gear H / C: High clutch R / C: Reverse clutch L / C: Low clutch 2 & 4 / B: 2nd / 4th speed band brake L & R / B: Low & reverse brake

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3J552 MA02 MA12 NA01 NB01 PA02 RA07 RB16 SA10 TA01 VA32W VA32Y VA34W VA48Z VB01Z VC01W VC05Z VD01W

Claims (8)

[Claims] 1. A shift control device for an automatic transmission configured to shift by changing a friction engagement element that simultaneously performs engagement control and release control of two different friction engagement elements, wherein the shift control apparatus accompanies depression of an accelerator. A shift control device for an automatic transmission, wherein a start of the release control is delayed by a predetermined period when a downshift is requested. 2. When a downshift request is made due to depression of an accelerator, and when the vehicle is coasting when the downshift request is issued, the start of the release control is delayed by a predetermined period. The shift control device for an automatic transmission according to claim 1, wherein the shift control is performed. 3. The shift control device for an automatic transmission according to claim 2, wherein the predetermined period is a period from a coasting running state to a running state to which a driving force is applied. 4. The shift control device for an automatic transmission according to claim 1, wherein the predetermined period is a period until a change in an engine operation state accompanying depression of the accelerator reaches a predetermined value. . 5. The shift of the automatic transmission according to claim 4, wherein a period until the change in the engine operation state reaches a predetermined value is a period until the rotation speed of the engine reaches a predetermined value. Control device. 6. A period until the change in the engine operating state reaches a predetermined value is a period until the input shaft torque of the automatic transmission reaches a predetermined value.
A shift control device for an automatic transmission according to claim 1. 7. The automatic transmission according to claim 2, wherein the coasting state and the driving state to which the driving force is applied are determined based on an input shaft torque of the automatic transmission. Control device. 8. The system according to claim 2, wherein the coasting running state and the running state to which the driving force is applied are determined based on a comparison between an engine speed and an input shaft speed of the automatic transmission. Or the shift control device of the automatic transmission according to 3.