CN113606330A

CN113606330A - Starting control method for automobile double-clutch automatic transmission

Info

Publication number: CN113606330A
Application number: CN202110949135.2A
Authority: CN
Inventors: 洪洁; 李明; 史力铭; 卞雷锋; 温敏; 吴全军
Original assignee: Anhui Jianghuai Automobile Group Corp
Current assignee: Anhui Jianghuai Automobile Group Corp
Priority date: 2021-08-18
Filing date: 2021-08-18
Publication date: 2021-11-05
Anticipated expiration: 2041-08-18
Also published as: CN113606330B

Abstract

The invention discloses a starting control method of an automobile double-clutch automatic transmission, which comprises the following steps: judging whether the vehicle is in a starting state or not; if so, calculating a starting target rotating speed; according to the starting target rotating speed, the automatic gearbox control unit sends a target rotating speed request to the engine; and responding to the target rotating speed request, and performing starting control on the vehicle according to the rotating speed difference between the current engine rotating speed and the target rotating speed requested by the automatic gearbox control unit, wherein the starting control comprises a rotating speed responding stage and a torque increasing stage which are sequentially performed. According to the starting control method of the automobile double-clutch automatic transmission, the engine responds to the target rotating speed request of the transmission to maintain the rotating speed of the engine, the rotating speed of the engine does not need to be maintained by increasing or reducing the torque of the clutch, the automatic transmission control unit rapidly increases the rotating speed of the input shaft to be synchronous with the rotating speed of the engine by combining the clutch, so that the linearity of the increase of the torque of the clutch can be improved, and the starting smoothness is improved.

Description

Starting control method for automobile double-clutch automatic transmission

Technical Field

The invention relates to the technical field of automobile starting, in particular to a starting control method of an automobile double-clutch automatic transmission.

Background

A dual clutch automatic transmission (DCT), which is a kind of mechanical automatic transmission appearing in recent years, is gaining attention due to its advantages of high shift speed, high transmission efficiency, and the like.

At present, the existing starting control technology of the double-clutch automatic transmission mainly has the following problems: on one hand, the clutch is worn due to overlong sliding friction time in the starting process; on the other hand, the clutch engaging speed and the engine torque are unreasonably matched in the starting process, so that the difficulty in the calibration process is increased, the phenomena of engine rotating speed fluctuation and unsmooth vehicle starting in the starting process are caused, and the whole vehicle driving feeling in the starting process is influenced. Therefore, the starting control of the dual-clutch automatic transmission is always a technical problem.

Therefore, a starting control method of the automobile dual-clutch automatic transmission is needed.

Disclosure of Invention

The invention aims to provide a starting control method of an automobile dual-clutch automatic transmission, which aims to solve the problems in the prior art, improve the acceleration response when starting and the acceleration smoothness during starting, and reduce the impact during starting.

The invention provides a starting control method of an automobile double-clutch automatic transmission, which comprises the following steps of:

step S1, judging whether the vehicle is in a starting state or not;

if yes, executing step S2, and calculating a starting target rotating speed;

step S3, according to the starting target rotating speed, the automatic gearbox control unit sends a target rotating speed request to the engine;

and step S4, responding to the target rotating speed request, and performing starting control on the vehicle according to the rotating speed difference between the current rotating speed of the engine and the target rotating speed requested by the automatic gearbox control unit, wherein the starting control process comprises a rotating speed response stage and a torque increasing stage which are sequentially performed.

The starting control method for the automobile dual-clutch automatic transmission as described above, preferably, the step S1 of determining whether the vehicle is in a starting state includes: if the following two conditions are simultaneously met, determining that the vehicle is in a starting state:

the opening degree of the accelerator pedal is greater than a set threshold value of the opening degree of the accelerator pedal;

the current engine speed is less than the set speed threshold value when starting.

The starting control method for the automobile dual-clutch automatic transmission as described above, wherein preferably, the step S2 of calculating the starting target rotation speed includes:

and calculating to obtain the starting target rotating speed of the engine according to the current actual gear of the vehicle, the opening degree of an accelerator pedal, the oil temperature of the transmission and the ramp load.

In the starting control method of the dual clutch automatic transmission for the vehicle as described above, it is preferable that the target rotational speed requested by the automatic transmission control means coincides with the calculated starting target rotational speed.

The starting control method for the dual clutch automatic transmission of the automobile as described above, wherein preferably, in step S4, in response to the target rotation speed request, the vehicle is controlled to start according to the rotation speed difference between the current engine rotation speed and the target rotation speed requested by the automatic transmission control unit, and the starting control process includes a rotation speed response phase and a torque increase phase which are sequentially performed, and specifically includes:

step S41, the electronic control unit determines the control stage of the clutch torque according to the relationship between the absolute value of the first speed difference between the current engine speed and the target speed requested by the automatic gearbox control unit and the first preset speed difference threshold value;

step S42, if the absolute value of the first speed difference between the current engine speed and the target speed requested by the automatic gearbox control unit is larger than or equal to the first preset speed difference threshold, performing clutch torque control on the clutch in the engine speed response stage;

step S43, if the absolute value of the first speed difference between the current engine speed and the target speed requested by the automatic gearbox control unit is smaller than the first preset speed difference threshold value, performing second-stage torque control on the clutch;

step S44, judging whether a second speed difference between the current engine speed and the speed of the input shaft corresponding to the current gear of the gearbox is smaller than a starting completion speed difference threshold value or not, if so, executing step S45; if not, returning to the step S43;

step S45 ends the start.

The starting control method for the dual clutch automatic transmission of the automobile as described above, preferably, the step S42, performing the clutch torque control of the clutch in the engine speed response phase, specifically includes:

calculating a third rotation speed difference between the starting target rotation speed and the current engine rotation speed in real time;

calculating the change rate of the engine speed;

according to a third speed difference between the current engine speed and the starting target speed and the change rate of the engine speed, looking up a table to obtain a first clutch torque change amount;

and obtaining the clutch torque at the next moment of the engine speed response stage according to the current clutch torque and the first clutch torque variation.

The starting control method for the dual clutch automatic transmission of the automobile as described above, wherein the step S43 of performing the second stage torque control on the clutch preferably includes:

obtaining a second clutch torque variation according to the accelerator opening, the current engine flywheel end torque and the current clutch torque;

obtaining the torque variation of a third clutch according to the variation rate of the torque of the flywheel end of the engine;

calculating the torque variation of a fourth clutch in a PI closed-loop control mode according to the current engine speed and the starting target speed;

and obtaining the clutch torque at the next moment of the second stage according to the clutch torque, the second clutch torque variation, the third clutch torque variation and the fourth clutch torque variation when the engine speed response stage is finished.

The starting control method for the automobile dual-clutch automatic transmission preferably obtains the second clutch torque variation according to the accelerator opening, the current engine flywheel end torque and the current clutch torque, and specifically includes:

looking up a table according to the opening degree of the accelerator to obtain a power coefficient;

calculating the torque difference between the current flywheel end torque of the engine and the current clutch torque;

and obtaining the torque variation of the second clutch according to the torque difference between the power coefficient and the torque of the flywheel end of the current engine and the torque of the current clutch.

The starting control method for the automobile dual-clutch automatic transmission, wherein preferably, the calculating the torque variation of the fourth clutch by a PI closed-loop control method according to the current engine speed and the starting target speed specifically includes:

obtaining proportional control calculation torque according to the third rotation speed difference and the proportional term control parameter;

calculating a speed difference change rate of a third speed difference between the starting target speed and the current engine speed;

obtaining integral control calculation torque according to the rotating speed difference change rate and the integral term control parameter;

and calculating the torque according to the proportional control calculation torque and the integral control calculation torque to obtain the torque variation of the fourth clutch.

The starting control method for the dual clutch automatic transmission of the automobile as described above, preferably, in step S4, the starting control for the vehicle is performed in response to the target rotational speed request based on a rotational speed difference between a current engine rotational speed and a target rotational speed requested by the automatic transmission control means, and the method further includes:

after step S42 is executed, the magnitude relation between the absolute value of the first rotational speed difference between the current engine rotational speed and the target rotational speed requested by the automatic transmission control unit and a first preset rotational speed difference threshold is judged,

if the absolute value of the first speed difference between the current engine speed and the target speed requested by the automatic gearbox control unit is greater than or equal to the first preset speed difference threshold, returning to the step S42, and performing clutch torque control on the clutch in an engine speed response stage;

and if the absolute value of the first speed difference between the current engine speed and the target speed requested by the automatic gearbox control unit is smaller than the first preset speed difference threshold value, executing step S43 and carrying out second-stage torque control on the clutch.

According to the starting control method of the automobile double-clutch automatic transmission, the automatic transmission control unit sends a target rotating speed request to the engine, the engine responds to the target rotating speed request of the transmission to maintain the rotating speed of the engine, the torque of the clutch does not need to be increased or reduced to maintain the rotating speed of the engine, the automatic transmission control unit is combined with the clutch to quickly increase the rotating speed of the input shaft to be synchronous with the rotating speed of the engine, and therefore the linearity of the increase of the torque of the clutch can be improved, and the starting smoothness is improved.

Drawings

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be further described with reference to the accompanying drawings, in which:

FIG. 1 is a schematic diagram of a conventional launch control;

FIG. 2 is a flowchart of an embodiment of a method for controlling a launch of a dual clutch automatic transmission of a vehicle according to the present invention;

FIG. 3 is a logic block diagram of an embodiment of a method for controlling a start of a dual clutch automatic transmission of a vehicle according to the present invention;

FIG. 4 is a clutch torque control logic diagram during an engine speed response phase provided by the present invention;

FIG. 5 is a second stage torque control logic diagram for the clutch provided by the present invention;

FIG. 6 is a schematic diagram of the launch control of the present invention.

Detailed Description

Various exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. The description of the exemplary embodiments is merely illustrative and is in no way intended to limit the disclosure, its application, or uses. The present disclosure may be embodied in many different forms and is not limited to the embodiments described herein. These embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. It should be noted that: the relative arrangement of parts and steps, the composition of materials, numerical expressions and numerical values set forth in these embodiments are to be construed as merely illustrative, and not as limitative, unless specifically stated otherwise.

As used in this disclosure, "first", "second": and the like, do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. The word "comprising" or "comprises", and the like, means that the element preceding the word covers the element listed after the word, and does not exclude the possibility that other elements are also covered. "upper", "lower", and the like are used merely to indicate relative positional relationships, and when the absolute position of the object being described is changed, the relative positional relationships may also be changed accordingly.

In the present disclosure, when a specific component is described as being located between a first component and a second component, there may or may not be intervening components between the specific component and the first component or the second component. When it is described that a specific component is connected to other components, the specific component may be directly connected to the other components without having an intervening component, or may be directly connected to the other components without having an intervening component.

All terms (including technical or scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs unless specifically defined otherwise. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail, but are intended to be part of the specification where appropriate.

As shown in fig. 1, the conventional starting control strategy uses the torque at the flywheel end of the engine as a reference torque, uses a set target rotational speed as a reference rotational speed, and then controls the torque of the clutch to increase the rotational speed of the input shaft of the transmission to be synchronous with the rotational speed of the engine. The prior art has the following defects for the starting control of the double-clutch automatic gearbox: the starting process is mainly characterized in that the target engine rotating speed is maintained by adjusting the torque of the clutch, when the starting is started, the torque of the engine is small, and at the moment, the rotating speed of the engine is increased, and the torque of the clutch must be kept in a low state; then when the rotating speed of the engine reaches the target rotating speed, in order to maintain the stable rotating speed of the engine, the torque of the clutch needs to be continuously adjusted according to the actual rotating speed of the engine, so that the calibration difficulty is increased, the acceleration in the starting process is not smooth, the starting impact is seriously caused, and the driving performance of the whole vehicle is influenced.

As shown in fig. 2 and fig. 3, the starting control method for the dual-clutch automatic transmission of the automobile provided by the embodiment specifically includes the following steps in an actual execution process:

and step S1, determining whether the vehicle is in a starting state.

Step S1, determining whether the vehicle is in a starting state, specifically including: if the following two conditions are simultaneously met, determining that the vehicle is in a starting state: (a) the opening degree of the accelerator pedal is greater than a set threshold value of the opening degree of the accelerator pedal; (b) the current engine speed is less than the set speed threshold value when starting.

If it is determined that the vehicle is in the starting state, step S2 is executed to calculate a starting target rotation speed.

Specifically, the starting target rotating speed of the engine is calculated according to the actual gear of the current vehicle, the opening degree of an accelerator pedal, the oil temperature of the transmission and the ramp load.

And step S3, according to the starting target rotating speed, sending a target rotating speed request to an engine by an automatic Transmission Control Unit (TCU).

Specifically, the TCU sends a target rotation speed request to an Electronic Control Unit (ECU) of the engine. As shown in fig. 3, the target rotational speed requested by the automatic transmission control unit is equal to the calculated starting target rotational speed, and both are N_tgt。

In an embodiment of the starting control method for the dual clutch automatic transmission of the vehicle according to the present invention, the step S4 may specifically include:

step S41, the electronic control unit calculates a target speed (N) requested by the automatic transmission control unit according to the current engine speed (EngN)_tgt) With a first predetermined speed difference threshold (Δ) from an absolute value of the first speed difference_rpm) Determines the control stage of the clutch torque.

Step S42, if the current engine speed (EngN) and the target speed (N) requested by the automatic gearbox control unit_tgt) Is greater than or equal to the first preset speed difference threshold value (delta)_rpm) Then, the clutch is subjected to clutch torque control in the engine speed response phase, that is, the clutch torque control in the first phase is performed.

As shown in fig. 4, in an embodiment of the starting control method for the dual clutch automatic transmission of the automobile according to the present invention, the step S42 may specifically include:

step S421, calculating the starting target rotating speed (N) in real time_tgt) A third speed difference from the current engine speed (EngN).

Specifically, the starting target rotational speed (N)_tgt) The third speed difference is obtained by subtracting the current engine speed (EngN).

And step S422, calculating the change rate of the engine speed.

And step S423, looking up a table to obtain the torque variation of the first clutch according to the third speed difference between the current engine speed and the starting target speed and the variation rate of the engine speed.

And step S424, obtaining the clutch torque at the next moment of the engine speed response stage according to the current clutch torque and the first clutch torque variation.

Specifically, the current clutch torque and the first clutch torque variation are added to obtain the clutch torque at the next moment.

Further, as shown in fig. 3, in some embodiments of the present invention, the step S4 further includes:

after step S42 is executed, the current engine speed (EngN) and the target speed (N) requested by the automatic transmission control unit are judged_tgt) With a first predetermined speed difference threshold (Δ) from an absolute value of the first speed difference_rpm) The relationship between the size of the first and the second,

if the current engine speed (EngN) and the target speed (N) requested by the automatic gearbox control unit_tgt) Is greater than or equal to the first preset speed difference threshold value (delta)_rpm) Returning to step S42, performing clutch torque control in an engine speed response phase for the clutch;

if the current engine speed (EngN) and the target speed (N) requested by the automatic gearbox control unit_tgt) Is smaller than said first preset rotational speed difference threshold value (Δ)_rpm) Then step S43 is executed to perform the second stage torque control of the clutch.

And step S43, if the absolute value of the first speed difference between the current engine speed and the target speed requested by the automatic gearbox control unit is smaller than the first preset speed difference threshold value, performing second-stage torque control on the clutch.

As shown in fig. 5, in an embodiment of the starting control method for the dual clutch automatic transmission of the automobile according to the present invention, the step S43 may specifically include:

and step S431, obtaining the torque variation of the second clutch according to the accelerator opening, the current flywheel end torque of the engine and the current clutch torque.

In an embodiment of the starting control method of the dual clutch automatic transmission for the vehicle according to the present invention, the step S431 may specifically include:

and S4311, looking up a table according to the opening degree of the accelerator to obtain the power coefficient.

The larger the opening degree of the accelerator is, the larger the corresponding power coefficient is, and the corresponding relation between the opening degree of the accelerator and the power coefficient can be obtained through a Map table calibrated in advance.

And step S4312, calculating the torque difference between the current flywheel end torque of the engine and the current clutch torque.

Specifically, the torque difference is obtained by subtracting the current clutch torque from the current engine flywheel end torque.

And S4313, obtaining the torque variation of the second clutch according to the power coefficient and the torque difference between the current flywheel end torque of the engine and the current clutch torque.

Specifically, the power coefficient obtained in step S4311 is multiplied by the torque difference obtained in step S4312, and the two-clutch torque variation is obtained.

And S432, obtaining the torque variation of the third clutch according to the torque variation rate of the flywheel end of the engine.

And S433, calculating the torque variation of the fourth clutch in a PI closed-loop control mode according to the current engine rotating speed and the starting target rotating speed.

In an embodiment of the starting control method for the dual clutch automatic transmission of the vehicle according to the present invention, the step S433 may specifically include:

and S4331, calculating a third rotation speed difference between the starting target rotation speed and the current engine rotation speed in real time.

As described above, the starting target rotational speed (N)_tgt) The third speed difference is obtained by subtracting the current engine speed (EngN).

And S4332, obtaining a proportional control calculation torque according to the third speed difference and the proportional (P) term control parameter.

Specifically, the third speed difference is multiplied by the proportional (P) term control parameter, and the proportional control calculated torque is obtained.

Step S4333, calculating the starting target rotational speed (N)_tgt) A speed difference change rate from a third speed difference of the current engine speed (EngN).

And S4333, obtaining integral control calculation torque according to the rotating speed difference change rate and the integral term control parameter.

Specifically, the rotating speed difference change rate is multiplied by the integral term control parameter, and the integral control calculation torque is obtained.

And S4334, calculating the torque according to the proportional control calculation torque and the integral control calculation torque to obtain a torque variation of a fourth clutch.

Specifically, the torque variation of the fourth clutch is obtained by adding the proportional control calculation torque and the integral control calculation torque.

And step S434, obtaining a clutch torque at the next moment of the second stage according to the clutch torque at the end of the engine speed response stage, the second clutch torque variation, the third clutch torque variation, and the fourth clutch torque variation.

Specifically, the clutch torque at the end of the engine speed response phase, the second clutch torque variation, the third clutch torque variation and the fourth clutch torque variation are added to obtain the clutch torque at the next moment. The first clutch torque variation, the second clutch torque variation, the third clutch torque variation, and the fourth clutch torque variation of the present invention may be positive values, negative values, or 0, and the present invention is not particularly limited thereto.

Step S44, judging the current engine speed (EngN) and the input shaft speed (N) corresponding to the current gear of the gearbox_inp) Is less than the start completion speed difference threshold value (θ), if yes, step S45 is executed; if not, the process returns to step S43 to continue the second-stage torque control of the clutch.

Step S45 ends the start.

The starting control method for the automobile dual-clutch automatic transmission is mainly used for the starting control process of the automobile with the dual-clutch automatic transmission, and can also be popularized and applied to the starting control process of other automatic transmissions which use clutches to transmit power, such as an Automated Manual Transmission (AMT).

Therefore, as shown in fig. 6, the starting control strategy of the present invention mainly sends a target rotation speed request to the electronic control unit through the automatic transmission control unit during starting, the electronic control unit stabilizes the engine rotation speed at the target rotation speed requested by the automatic transmission control unit in response to the target rotation speed request sent by the automatic transmission control unit, and then the automatic transmission control unit rapidly increases the rotation speed of the input shaft to be synchronous with the engine rotation speed by combining the clutch, and starting is completed. The first stage is that the engine speed responds to a target speed request sent by an automatic gearbox control unit to increase the engine speed to the target speed; the second stage is a clutch torque rapid increasing stage until the rotation speed of the input shaft is synchronous with the rotation speed of the engine, and starting is completed.

According to the starting control method of the automobile double-clutch automatic transmission provided by the embodiment of the invention, the automatic transmission control unit sends a target rotating speed request to the engine, the rotating speed of the engine is maintained by responding the target rotating speed request of the transmission through the engine, the rotating speed of the engine is maintained without increasing or reducing the torque of the clutch, and the rotating speed of the input shaft is rapidly increased to be synchronous with the rotating speed of the engine by combining the clutch, so that the linearity of the increase of the torque of the clutch can be improved, and the starting smoothness is improved.

Thus, various embodiments of the present disclosure have been described in detail. Some details that are well known in the art have not been described in order to avoid obscuring the concepts of the present disclosure. It will be fully apparent to those skilled in the art from the foregoing description how to practice the presently disclosed embodiments.

Although some specific embodiments of the present disclosure have been described in detail by way of example, it should be understood by those skilled in the art that the foregoing examples are for purposes of illustration only and are not intended to limit the scope of the present disclosure. It will be understood by those skilled in the art that various changes may be made in the above embodiments or equivalents may be substituted for elements thereof without departing from the scope and spirit of the present disclosure. The scope of the present disclosure is defined by the appended claims.

Claims

1. A starting control method of an automobile double-clutch automatic transmission is characterized by comprising the following steps:

step S1, judging whether the vehicle is in a starting state or not;

if yes, executing step S2, and calculating a starting target rotating speed;

2. The starting control method for the automobile dual-clutch automatic transmission according to claim 1, wherein the step S1 of determining whether the vehicle is in a starting state specifically comprises: if the following two conditions are simultaneously met, determining that the vehicle is in a starting state:

3. The starting control method for the automobile dual-clutch automatic transmission according to claim 1, wherein the step S2 of calculating the starting target rotating speed specifically comprises:

4. The starting control method for the automotive dual clutch automatic transmission according to claim 1, characterized in that the target rotational speed requested by the automatic transmission control unit coincides with the calculated starting target rotational speed.

5. The method for controlling starting of an automobile dual-clutch automatic transmission according to claim 1, wherein step S4 is to perform starting control on the vehicle according to a rotational speed difference between a current engine rotational speed and a target rotational speed requested by the automatic transmission control unit in response to the target rotational speed request, and the starting control process includes a rotational speed response phase and a torque increase phase which are performed in sequence, and specifically includes:

step S45 ends the start.

6. The method for controlling the start of the automatic dual-clutch transmission of the automobile as claimed in claim 5, wherein the step S42 of performing the clutch torque control in the engine speed response phase on the clutch specifically comprises:

calculating the change rate of the engine speed;

7. The method for controlling the starting of the automatic dual-clutch transmission of the automobile as claimed in claim 5, wherein the step S43 of performing the second stage torque control on the clutch specifically comprises:

8. The starting control method of the automobile dual-clutch automatic transmission according to claim 7, wherein the obtaining of the second clutch torque variation according to the accelerator opening, the current engine flywheel end torque and the current clutch torque specifically comprises:

9. The starting control method of the automobile dual-clutch automatic transmission according to claim 7, wherein the calculating of the torque variation of the fourth clutch by a PI closed-loop control method according to the current engine speed and the starting target speed specifically comprises:

10. The method for controlling starting of an automotive dual clutch automatic transmission according to claim 5, wherein said step S4, in response to the target rotational speed request, performs starting control of the vehicle based on a rotational speed difference between a current engine rotational speed and a target rotational speed requested by the automatic transmission control unit, further comprising: