CN112460253B

CN112460253B - Control method for time step length of quick oil filling stage of automatic transmission

Info

Publication number: CN112460253B
Application number: CN202011578230.8A
Authority: CN
Inventors: 杨涛; 邱兵; 杨治学
Original assignee: Shengrui Transmission Co Ltd
Current assignee: Shengrui Transmission Co Ltd
Priority date: 2019-12-30
Filing date: 2020-12-28
Publication date: 2022-05-06
Anticipated expiration: 2040-12-28
Also published as: CN112460253A; CN111022635A; CN112413110A; CN112413110B

Abstract

The invention discloses a control method of time step length of a quick oil filling stage of an automatic transmission, which comprises the steps of manually determining the quick oil filling time and a slip critical value of the automatic transmission; confirming a batch slip threshold

And a step of FT for batch quick oil filling time; determining self-learning clutch slip n_negAnd learning step length

The self-learning method has the advantages that time step self-learning can be carried out during gear shifting, self-adaptive control of oil filling time of the clutch in a rapid oil filling stage is achieved, software coverage is improved, gear shifting impact is avoided, and protection of a gearbox is facilitated.

Description

Control method for time step length of quick oil filling stage of automatic transmission

Technical Field

The invention belongs to the technical field of automatic transmission control, and particularly relates to a control method for time step length of a quick oil filling stage of an automatic transmission.

Background

A complete upshift process of an AT automatic transmission can be divided into 3 stages, as shown in fig. 1, and a clutch shift process is composed of three parts, an oil pressure build stage, a torque exchange stage, and a speed change stage.

An oil pressure establishing stage: the OG clutch begins draining oil and the OC clutch builds up oil pressure from 0. In the torque phase, the OG clutch and the OC clutch realize torque exchange, and the OC clutch bears the torque borne by the OG clutch before. And in the phase-changing stage, the adjustment of the rotating speed of the turbine is realized according to a target gear, and then gear shifting is completed.

The oil pressure establishing stage is divided into a clutch fast oil charging stage (FastPoint) and a clutch friction plate combining stage (KissPoint), and the main control mode of the FastPoint stage is to use higher oil pressure to quickly fill oil in a clutch cavity, so that the oil charging time has important influence on the gear shifting quality. If the oil filling time is controlled to be too long, oil in the clutch cavity can be filled with oil, meanwhile, enough pressure can be generated to push the friction plates to be combined, and the clutch is combined in advance in the oil pressure building stage to cause gear shifting impact, so that the gear shifting smoothness is affected. If the control oil pressure is too small, the gear shifting time is prolonged, the gear shifting response is slow, friction plates are abraded, and the gearbox is damaged. Therefore, in one shift, the timing of the oil pressure build-up phase is critical. Due to the difference of electromagnetic valves of the gearbox and the gradual change of the required pressure of the same gearbox in the life cycle, a single oil filling time parameter cannot meet the requirement of software coverage.

Because the oil pressure holding time is controlled in the fast oil charging stage to be too long, the actual oil pressure can jump, the oil pressure jumps, the OC clutch friction plate can be combined in advance to enable the clutch to be matched and interfered, finally, the turbine rotating speed jumps, serious impact is generated in the gear shifting process, and the driving smoothness is influenced, as shown in fig. 2.

AT present, domestic AT automatic transmission control software and self-adaptive technology thereof are few and few, are basically in a blank state, and have not found that the control software can realize time step self-learning during gear shifting.

Disclosure of Invention

The invention aims to solve the technical problem of providing a control method for oil filling time in a quick oil filling stage of an automatic transmission, overcoming the defects of the existing control method, realizing time step self-learning during gear shifting by adopting the control method, avoiding gear shifting impact and being beneficial to protecting a gearbox.

In order to solve the technical problem, the technical scheme of the invention is as follows: the control method of the time step length of the quick oil filling stage of the automatic transmission is characterized by comprising the following steps of: manually determining the quick oil filling time and the slip critical value of the automatic transmission;

identifying a batch slip threshold

And a step of FT for batch quick oil filling time;

determining self-learning clutch slip n_negAnd learning step length

A step of;

and (5) self-learning of software.

Further, the step of manually determining the fast fill time and the slip threshold of the automatic transmission comprises:

with a default oil-filled time FT_defOn the basis of a step-wise increase in the filling time, the increase being in steps FT_stepCalculating and recording the clutch slip after increasing the oil charge time each time;

when the impact is detected, the oil filling time before the impact occurs is used as the quick oil filling time of the gearbox, and the clutch slip before the impact occurs is used as the slip critical value of the gearbox slip impact.

Further, a batch slip threshold is identified

The method comprises the following steps:

after determining the slip critical values of a plurality of transmissions, eliminating abnormal slip critical values, and selecting the minimum slip critical value as a batch slip critical value

。

Further, the step of determining the batch fast oil filling time FT comprises the following steps:

and after the quick oil filling time of a plurality of transmissions is determined, eliminating the abnormal quick oil filling time, and selecting the maximum quick oil filling time as the quick oil filling time FT of the whole batch project.

Further, a self-learning clutch slip n is determined_negAnd learning step length

The method comprises the following steps:

starting from the time of oil filling before the impact occurs, will increase by x steps FT_stepThe clutch slip after that is taken as the clutch slip n_negFirst slip n of_neg1Taking x-h step length FT_stepThe sum of which is the learning step length

；

Continue to increase by y steps FT_stepThe clutch slip after that is taken as the clutch slip n_negSecond slip n_neg2Taking y-h step lengths FT_stepThe sum of the learning step length

；

Continue to increase by z steps FT_stepThe clutch slip thereafter being a third slip n_neg3Taking z-h step sizes FT_stepThe sum of which is the learning step length

。

Further, the step size is learned

The number of (2) is 18-22.

Further, the software self-learning step comprises the following steps:

during gear shifting, the actual slip of the clutch is detected to exceed the slip critical value

If yes, judging the clutch is overfilled, calculating the actual slip of the clutch, and determining the slip n of the self-learning clutch_negAnd corresponding learning step length

Controlling the next shift time minus the corresponding learning step length

。

Further, the software self-learning step further comprises:

continuously detecting actual slip of the clutch, and if the actual slip is larger than the slip critical value

Then the above operations are repeated until the actual slip of the clutch is less than the slip threshold

And exiting self-learning, and taking the corresponding oil filling time as the quick oil filling time of the gearbox and storing the quick oil filling time in a gearbox controller.

By adopting the technical scheme, compared with the prior art, the invention has the following advantages: the self-learning of time step length can be carried out during gear shifting, self-adaptive control of the oil charging time of the clutch in the rapid oil charging stage is realized, the software coverage is improved, gear shifting impact is avoided, and the protection of the gearbox is facilitated.

Drawings

FIG. 1 is a control timing diagram for a normal upshift shifting process for a transmission;

FIG. 2 is a timing diagram of the overfill;

FIG. 3 is a timing diagram illustrating the determination of default fill time and actual slip in the fast fill time according to an embodiment of the present invention;

FIG. 4 is a timing diagram of the oil fill time and the actual slip for one step added to the determination of the fast oil fill time in an embodiment of the present invention;

FIG. 5 is a timing diagram illustrating the oil fill time and the actual slip for determining n steps in the fast oil fill time according to an embodiment of the present invention;

FIG. 6 is a timing diagram of the oil fill time and actual slip when the self-learning step first shifts to generate a bump in an embodiment of the present invention;

FIG. 7 is a timing diagram of the oil fill time and actual slip after the first adjustment by the self-learning step in an embodiment of the present invention;

FIG. 8 is a timing diagram of the oil fill time and actual slip after the self-learning step adjustment is completed in an embodiment of the present invention.

Detailed Description

In order to more clearly understand the technical features, objects and effects of the present invention, the embodiments of the present invention will be described with reference to the accompanying drawings, and it will be understood by those skilled in the art that the following should not be construed as limiting the scope of the present invention.

In the embodiment, as shown in fig. 6-8, a method for controlling the time step of the fast oil filling stage of an automatic transmission, during normal driving, when a gear shifting signal is detected, the clutch is slipped

And

comparing, and controlling the time step of FastPoint according to the comparison result;

when detecting that

≤

When the fast shift command is received, the fast shift command is not subjected to time step control, and a next shift command is waited;

when in use

＞

When the oil is excessively filled, the software judges that the oil is excessively filled, calculates the time step length required to be reduced according to the table 1, and controls the next gear shifting time to subtract the time step length;

next shift continue detection

Up to

≤

And stopping time step control and waiting for the next gear shifting command.

And controlling the clutch in the quick oil filling stage by using the clutch slip as a judgment basis.

In the formula:

is the target rotational speed of the clutch,

the actual rotational speed of the clutch is indicated,

for the transmission ratio of the present gear position,

the rotational speed of the output shaft is,

different gearboxes are arranged differently for the clutch slip threshold.

From the above formula

The rotating speed of the clutch pushed back by the rotating speed of the output shaft,

for clutch speed monitored by sensors, and therefore during normal gear shifting

。

The control method of the time step of the automatic clutch in the quick oil filling stage comprises the following steps:

the first step is as follows: manually determining a fast fill time FT and a slip threshold for an automatic transmission

With software default oil fill time FT_defOn the basis of a step-wise increase in the filling time, the increase being in steps FT_stepAnd calculating and recording the clutch slip after increasing the oil filling time each time. FT_defTypically set to 100 + -20 ms, FT_stepTypically set at 10ms, which is adjusted for different transmissions.

The method comprises the following specific steps:

as shown in FIGS. 3-5, FIG. 3 shows the default oil fill time FT_defThe actual slip N of the clutch at the moment is recorded_thrAt FT_defAdding a step size FT on the basis_step(see FIG. 4), the oil-filling time at this time is FT_step1（FT_step1=FT_def+FT_stepAnd so on) and then record the clutch slip N at that time_thr1Then continues to increase the step size FT_stepAnd recording the time of fill and clutch slip at this time, as in FT_defAdding n step lengths FT on the basis_stepThen, an impact (as shown in FIG. 5) occurred, and the oil-filling time FT at that time was recorded_stepnAnd clutch slip N_thrn(see fig. 5) and then choose to increase n-1 steps FT_stepTime of oil charge FT_stepn-1The fast oil filling time FT of the gearbox is selected to increase n-1 step length FT_stepTime clutch slip N_thrn-1As a slip threshold for the impact of the gearbox slip

。

Because the time required by the quick oil filling of the gearbox is different due to the problems of assembly of the gearbox, processing consistency of parts and the like, a plurality of transmissions are selected when the quick oil filling time FT is determined, generally 10 transmissions are selected to meet the batch requirement, repeated testing is carried out according to the steps, then the quick oil filling time obtained by each gearbox is integrated, the abnormal quick oil filling time is eliminated, the abnormality refers to the fact that indexes of the mass-produced transmissions are consistent, the quick oil filling time of the plurality of transmissions is within a certain reasonable interval, and if a numerical value with a larger difference with other data occurs, the abnormality is judged; and selecting the maximum quick oil filling time as the quick oil filling time FT of the whole batch project. The reason for selecting the maximum value is that the oil filling time is too short, so that the oil filling is insufficient in the gear shifting process, and the serious result of damaging the gearbox is caused by insufficient oil filling. When the value is larger than the fast oil filling time FT of the gearbox, the self-learning function of the software is triggered, and then the oil filling time is learned and adjusted to ensure the gear shifting quality.

The second step is that: identifying a batch slip threshold

Determining slip threshold values for multiple transmissions

Then, the abnormal slip critical value is eliminated

Selecting the minimum threshold value of slip

As a bulk slip threshold

The corresponding oil filling time is used as the batch quick oil filling time FT, and the abnormity refers to that the indexes of the mass-produced transmissions are consistent, and the slip critical values of a plurality of transmissions are

Should be within a certain reasonable interval of time,if a numerical value which is greatly different from other data appears, judging the data to be abnormal; because of the slip threshold

Can cover the impact slip of the gearbox to the maximum extent.

The third step: determining self-learning clutch slip n_negAnd learning step length

When in FT_defAdding n step lengths FT_stepIn the presence of shock, i.e. the fast fill time FT and the slip threshold

Initially, it continues with a step size FT_stepIncreasing oil fill time to determine self-learning clutch slip n_neg。

Self-learning clutch slip n_negSelecting: time FT of oil charge from before the occurrence of impact_stepn-1To begin with, x (6 in this example) steps FT will be added_stepThe following clutch slip is taken as the first slip n_neg1Taking x-h step size FT_stepThe sum of the learning step length

(ii) a Continue to increase by y (9 in this example) steps

Long FT_stepThe clutch slip after that is taken as the second slip n_neg2Taking y-h step lengths FT_stepThe sum of the learning step length

(ii) a Z (12 in this example) steps FT are continued to be added_stepThe clutch slip thereafter being a third slip n_neg3Taking z-h step sizes FT_stepThe sum of the learning step length

.., the analogy is repeated, in this example, h takes a value of 2, two time steps are subtracted, the purpose of the setting is mainly to prevent that oil filling is insufficient due to too long reduction time of a gearbox, the number of the subtracted steps is not limited, and the adjustment is performed according to actual conditions. Wherein the values of x, y and z can be adjusted according to different conditions, and in general, x is adjusted<y<z, as in Table 1:

TABLE 1

	0	n_thr	n_neg1	n _neg2	n _neg3
						FastPointTm	0	0	Tm _neg1	Tm _neg2	Tm _neg3

n_neg1、 n_neg2、 n_neg3Arranged according to the performance of the vehicle

The value of the one or more of the one,

、

、

learning step sizes for FastPoint phases

Generally, about 20 learning steps are set

Empirically different gearboxes have errors but do not differ significantly.

Slip n of clutch_negThis is provided because the closer to the slip threshold value the more

The higher the control accuracy required for the rotational speed point of (1) and the smaller the impact feeling, the slip threshold value is set

The nearby impact area needs fine multi-step adjustment to prevent damage to the gearbox caused by too short control time. The farther the slip is from the threshold

The larger the point impact, the faster the adjustment to the slip threshold is required

Then fine tuning so as to move away from the slip threshold

A large time step may be selected.

The fourth step: software self-learning step

In the normal shifting process

If FastPoint is too long, overfilling (FIG. 2) can result, which can cause the OC clutch to engage prematurely, causing turbine speed fluctuations

. Thereby can be provided with

The value is used as the judgment basis of the overfilled oil working condition.

During one gear shifting, when the gearbox control software detects that the actual slip of the clutch exceeds the slip critical value

After that, i.e.

Determining to be overfilled, shortening FastPoint phase time (see FIG. 6), and calculating actual clutch slip

Then look-up table and self-learning clutch slip n_negComparing (Table 1) to confirm the position of the clutch slip in Table 1, and comparing the clutch slip n in the table with the self-learning clutch slip n_negCorresponding learning step length

And then subtracting the look-up table from the next shift

Value (see fig. 7) while continuing to detect clutch slip at that time, and re-monitoring

If the slip of the tested clutch is still greater than the slip threshold, the above operations are repeated until the actual slip of the clutch is less than the slip threshold, i.e. the clutch is opened

At the moment, the software considers that the gear shifting state reaches the target requirement (figure 8), self-learning is quitted, and the corresponding oil filling time at the moment is taken as the speed changeThe time for the tank to fill quickly is stored in the transmission controller.

The foregoing is illustrative of the best mode contemplated for carrying out the present invention and the details not specifically mentioned are within the knowledge of one of ordinary skill in the art. The protection scope of the invention is subject to the content of the claims

Equivalent modifications based on the teachings of the present invention are also within the scope of the present invention.

Claims

1. The control method of the time step length of the quick oil filling stage of the automatic transmission is characterized by comprising the following steps of:

the method comprises the steps of manually determining a fast fill time and a slip threshold of the automatic transmission, comprising:

when the impact is detected, taking the oil filling time before the impact occurs as the quick oil filling time of the automatic transmission, and taking the clutch slip before the impact occurs as the slip critical value of the slip impact of the automatic transmission;

identifying a batch slip threshold

And a step of FT for batch quick oil filling time;

identifying a batch slip threshold

The method comprises the following steps:

；

The step of determining the batch quick oil filling time FT comprises the following steps:

after the quick oil filling time of a plurality of transmissions is determined, the abnormal quick oil filling time is eliminated, and the maximum quick oil filling time is selected as the quick oil filling time FT of the whole batch project;

determining self-learning clutch slip n_negAnd learning step length

The method comprises the following steps:

starting from the time of oil charge before the occurrence of the impact, will increase by x steps FT_stepThe clutch slip after that is taken as the clutch slip n_negFirst slip n_neg1Taking x-h step size FT_stepThe sum of the learning step length

；

；

Continue to increase by z steps FT_stepThe clutch slip thereafter being a third slip n_neg3Taking z-h step sizes FT_stepThe sum of the learning step length

；

Self-learning of software:

Controlling the next shift time to subtract the corresponding learning step length

；

And exiting self-learning, and taking the corresponding oil filling time as the quick oil filling time of the automatic transmission and storing the quick oil filling time in a transmission controller.

2. The method of controlling a time step in a fast fill phase of an automatic transmission of claim 1, wherein: learning step length

The number of (2) is 18-22.