阅读说明：本技术 一种双离合自动变速箱离合器预同步控制方法 (Pre-synchronization control method for clutches of double-clutch automatic gearbox ) 是由 吴伟 王德伟 闵立 于 2020-12-04 设计创作，主要内容包括：本发明共公开一种双离合自动变速箱离合器预同步控制方法,其特征在于：判断当前挡位后在降挡前且是在预选挡位同步器动作之前的时间t内,让预选挡位离合器快速与发动机结合后再脱开,使预选挡离合器输入轴与发动机速度同步,并延长预选挡换挡过程的时间。本发明通过判断车辆是否处于低挡位降挡过程,以判断是否需要执行离合器预同步动作。通过执行离合器预同步动作,以减小预选挡位输入轴与输出轴之间的转速差,防止预选挡位输入轴与齿轮与同步器结合后出现先加速后减速的现象,从而有效地防止了车辆低速降挡过程中发生抖动异响的问题。(The invention discloses a pre-synchronization control method for clutches of a double-clutch automatic gearbox, which is characterized by comprising the following steps: and (3) in the time t before the gear is downshifted after the current gear is judged and before the pre-selected gear synchronizer acts, the pre-selected gear clutch is quickly combined with the engine and then disengaged, the speed of the input shaft of the pre-selected gear clutch is synchronized with the speed of the engine, and the time of the gear shifting process of the pre-selected gear is prolonged. The invention judges whether the pre-synchronization action of the clutch needs to be executed or not by judging whether the vehicle is in the low gear down-shifting process or not. The pre-synchronization action of the clutch is executed to reduce the speed difference between the input shaft and the output shaft of the pre-selected gear, and the phenomenon that the input shaft of the pre-selected gear is accelerated and then decelerated after being combined with the gear and the synchronizer is prevented, so that the problem of shaking and abnormal sound in the low-speed gear-down process of a vehicle is effectively prevented.)

1. A pre-synchronization control method for a clutch of a double-clutch automatic gearbox is characterized by comprising the following steps: and (3) in the time t before the gear is downshifted after the current gear is judged and before the pre-selected gear synchronizer acts, the pre-selected gear clutch is quickly combined with the engine and then disengaged, the speed of the input shaft of the pre-selected gear clutch is synchronized with the speed of the engine, and the time of the gear shifting process of the pre-selected gear is prolonged.

2. The dual clutch automatic transmission clutch presynchronization control method according to claim 1, characterized in that: the time t ranges from 0.25s to 0.33 s.

3. The dual clutch automatic transmission clutch presynchronization control method according to claim 1 or 2, characterized in that the downshift control procedure is as follows:

s1, judging whether the current gear is a low gear: "yes" to proceed to the next step, "no" to execute the normal shift routine;

s2, whether the accelerator pedal opening is reduced and the brake is applied: yes, the next step is carried out, wherein if no, a normal gear shifting program is executed;

s3, the gearbox preselects the next gear of the current gear, the TCU sends out an instruction to enable the clutch of the preselect gear to establish pressure to be combined with the engine within the time t before the action of the preselect gear synchronizer, and the pressure of the clutch is released when the rotating speed of the input shaft of the preselect gear reaches a set value;

and S4, executing a pre-gear selection operation and properly prolonging the gear shifting time.

4. The dual clutch automatic transmission clutch presynchronization control method according to claim 3, characterized in that: the low gear in S1 is the value 3 or 2.

5. The dual clutch automatic transmission clutch presynchronization control method according to claim 3, characterized in that: the set value in S3 is the current engine speed.

6. The dual clutch automatic transmission clutch presynchronization control method according to claim 3, characterized in that: in S4, the synchronizer operating time is 0.2S to 0.4S.

Technical Field

The invention belongs to the technical field of automatic transmissions, and particularly relates to a pre-synchronization control method for clutches of a double-clutch automatic transmission.

Background

The basic operating principle of a DCT (Dual clutch transmission) gearbox, namely a double-clutch gearbox, is that two independent clutches work alternately, one clutch is responsible for power transmission of odd gears, and the other clutch is responsible for power transmission of even gears. The DCT gearbox has two actions at each gear shift, namely engaging the current gear while preselecting the next gear, which the vehicle will preselect at the time of the current gear according to the driver's intention. Because of the large speed ratio difference between the low gears, the gearbox produces more obvious speed fluctuations during the downshift. Particularly, in the braking process of a vehicle, the speed change of an input shaft where a gear is preselected by a gearbox is large in the acceleration and deceleration processes, so that the rotating speed of the input shaft fluctuates sharply, and the impact of a transmission part is caused to generate shaking abnormal sound.

The problems of abnormal sound vibration, noise and noise of the DCT gearbox are main complaints of customers in the current market, the problem of vibration and noise of the DCT gearbox is determined by the inherent structure and cannot be fundamentally solved, and the abnormal sound problem is basically relieved by calibration measures in various large host factories at present. For the problem of abnormal braking noise of the DCT, the main solution is to reduce the gear shifting force of the pre-selected gear or prolong the gear shifting time of the pre-selected gear by adjusting calibration parameters, so as to reduce the abnormal braking noise of the gear shifting.

The DCT gearbox has two actions at each gear shift, namely engaging the current gear while preselecting the next gear, which the vehicle will preselect at the time of the current gear according to the driver's intention. Because the speed ratio difference between the low gears is large, the gearbox generates obvious rotation speed fluctuation in the process of gear reduction of the automobile in the low gears. Particularly, in the braking process of a vehicle, an input shaft where a gear of a gearbox is pre-selected can accelerate first and then decelerate, and the speed change is large in the acceleration and deceleration processes, so that the rotating speed of the input shaft fluctuates sharply, and the shock of a transmission part is caused to generate shaking abnormal sound.

In the prior art, abnormal sound is reduced by reducing the gear shifting force of the pre-selected gear or prolonging the gear shifting time of the pre-selected gear, so that the gear shifting speed is sacrificed when the gear shifting time is prolonged, and the gear shifting speed response is slowed down; on the other hand, the reduction effect of the prolonged shift time on the abnormal sound is not very obvious.

Disclosure of Invention

Aiming at the problems in the prior art, the invention aims to provide a pre-synchronization control method for a clutch of a dual-clutch automatic gearbox, which can effectively reduce the jitter abnormal sound.

In order to achieve the aim, the invention provides a method for pre-synchronizing control of a clutch of a double-clutch automatic gearbox, which is characterized by comprising the following steps: and (3) in the time t before the gear is downshifted after the current gear is judged and before the pre-selected gear synchronizer acts, the pre-selected gear clutch is quickly combined with the engine and then disengaged, the speed of the input shaft of the pre-selected gear clutch is synchronized with the speed of the engine, and the time of the gear shifting process of the pre-selected gear is prolonged.

Preferably, the time t is in the range of 0.25s to 0.33 s.

Preferably, the downshift control procedure is as follows:

s1, judging whether the current gear is a low gear: "yes" to proceed to the next step, "no" to execute the normal shift routine;

s2, whether the accelerator pedal opening is reduced and the brake is applied: yes, the next step is carried out, wherein if no, a normal gear shifting program is executed;

s3, the gearbox preselects the next gear of the current gear, the TCU sends out an instruction to enable the clutch of the preselect gear to establish pressure to be combined with the engine within the time t before the action of the preselect gear synchronizer, and the pressure of the clutch is released when the rotating speed of the input shaft of the preselect gear reaches a set value;

and S4, executing a pre-gear selection operation and properly prolonging the gear shifting time.

Preferably, the low gear in S1 is the value 3 or 2.

Preferably, the set value in S3 is the current engine speed.

Preferably, in S4, the operation time of the synchronizer is 0.2S to 0.4S

The invention has the beneficial effects that: on the basis of adjusting the gear shifting force and the gear shifting time, the invention adds the CBS function (the Clutch before synchronization Clutch is presynchronized), and increases the effect of reducing abnormal sound under the condition of sacrificing the minimum gear shifting speed.

The invention judges whether the pre-synchronization action of the clutch needs to be executed or not by judging whether the vehicle is in the low gear down-shifting process or not. The pre-synchronization action of the clutch is executed to reduce the speed difference between the input shaft and the output shaft of the pre-selected gear, and the phenomenon that the input shaft of the pre-selected gear is accelerated and then decelerated after being combined with the gear and the synchronizer is prevented, so that the problem of shaking and abnormal sound in the low-speed gear-down process of a vehicle is effectively prevented.

Drawings

FIG. 1is a simple schematic diagram of a dual clutch transmission;

FIGS. 2 and 3 are block diagrams of the synchronizer and the range gears;

fig. 4 is a flow chart of the present invention.

In the figure: IS-1, gearbox input shaft 1; IS-2, gearbox input shaft 2; OS, Output boot Output shaft (connecting wheels); g1-1, 1 st gear input shaft gear; g1-2, 1 gear output shaft gear; g2-1, 2-gear input shaft gear; g2-2, 2-gear output shaft gear; s1, a 1-gear synchronizer; s2, a 2-gear synchronizer; clutch K1, Clutch K1; clutch K2, Clutch K2; engine, Engine; wheel, Wheel; 1. a synchronizer internal structure; 2. a synchronous gear ring; 3. and a gear wheel.

Detailed Description

The technical solutions of the present invention (including the preferred ones) are described in further detail below by means of fig. 1 to 4 and enumerating some alternative embodiments of the present invention. It is to be understood that the described embodiments are merely a few embodiments of the invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present invention without any inventive step, are within the scope of the present invention.

As shown in fig. 1 to 4, in the method for controlling pre-synchronization of a clutch of a dual clutch automatic transmission according to the present invention, before the pre-selected gear synchronizer is activated, the pre-selected gear clutch is quickly coupled to the engine and then disengaged within a short time, generally 0.25s to 0.33s, so as to achieve the purpose of synchronizing the speed of the input shaft of the pre-selected gear clutch with the speed of the engine, and simultaneously, the time of the pre-selected gear shifting process is prolonged, thereby avoiding the problem of the chattering and abnormal sound caused by too fast rising of the rotation speed of the pre-selected gear input shaft and too violent fluctuation of the rotation speed, and the specific downshift control process is as follows:

1. judging the current gear, and if the current gear is 3 or 2, determining the current gear to be a low gear;

2. if the gear is a low gear and the brake is stepped on, the gearbox can downshift to pre-select the low gear;

3. taking the example of a 2-gear shift and a 1-gear shift, when the gearbox runs in the 2-gear shift, the clutch K2 (shown in FIG. 1) is combined with the engine to transmit power, and the power is transmitted to the 2-gear output shaft gear G2-2 through the 2-gear input shaft gear G2-1, G2-2 and the 2-gear synchronizer S2 to be connected so as to transmit the power to the output shaft OS;

4. after the brake is applied, the transmission is ready to pre-select gear 1. Before preselecting 1 gear, a TCU (Transmission control unit) sends a command to enable a 1-gear clutch K1 to build pressure to be combined with an engine, when the rotating speed of an input shaft reaches a set value, the clutch pressure is released, a clutch K1 is separated from the engine, and the rotating speed of the clutch K1 is synchronous with the rotating speed of the engine; namely, the speed of the input shaft 1IS-1 of the gearbox, the speed of the input shaft gear G1-1 of the 1 gear and the speed of the output shaft gear G1-2 of the 1 gear are consistent with the rotating speed of the engine, the output shaft gear G1-2 of the 1 gear IS not connected with the synchronizer S1 of the 1 gear, and the output shaft gear G1-2 of the 1 gear rotates on the output shaft OS in a idling mode and does not transmit power; clutch pressure is typically released when the input shaft speed reaches the current engine speed.

5. Executing a pre-selection gear operation, wherein the 1-gear synchronizer S1 synchronizes the speed with the 1-gear output shaft gear G1-2 through conical surface friction, and the speed of the 1-gear output shaft gear G1-2 is synchronized or close to the engine speed through a pre-synchronization function at the moment; at this time, the vehicle speed IS continuously reduced, the target speed of gear shifting (the gear shifting action IS executed only when the gear shifting box reaches the target rotating speed) IS also continuously reduced, the rotating speed difference between the input shaft 1IS-1 of the gear shifting box at this time and the target speed IS very small, and the gear shifting time IS properly prolonged, so that the rotating speed of the input shaft of the 1-gear IS slowly increased in the synchronizing process with the synchronizer S1, the rotating speed fluctuation IS smaller, and the problem of the jitter and the abnormal sound IS solved.

The speed of the input shaft of the pre-selection gear can be synchronized with the rotating speed of the engine through the step S4, and the speed difference between the pre-selection gear and the synchronizer is reduced; the step S5 is used for prolonging the time of the gear shifting process of the pre-selected gear, so that the problem that the speed of the input shaft rises too fast and the whole gear shifting process is milder is solved, and the problem of shaking and abnormal sound is solved, wherein in the general step S5, the action time of the synchronizer is 0.2S-0.4S.

Specifically, taking the case of a 2-gear shift down and a 1-gear shift down, the shift down process is as follows: when the vehicle is running in the 2-gear, the clutch K2 shown in FIG. 1is connected with the engine, and the driver steps on the brake pedal, so that the speed of the vehicle is reduced; the transmission is ready to pre-select 1 gear, the synchronizer of the 1 gear starts to act at the moment, the input shaft connected with the clutch K1 starts to accelerate gradually along with the output shaft along with the synchronizer, and the input shaft of the 1 gear is accelerated and then decelerated due to the deceleration of the vehicle, and the fluctuation of the rotating speed of the input shaft is large in the process, so that the jitter is generated. In order to solve the problems, the invention provides a control method, before the 1 st gear preselection synchronous action, the clutch K1 of the input shaft of the 1 st gear is combined with the engine to achieve speed synchronization and then released, so as to reduce the speed difference between the rotating speed of the input shaft of the preselection gear and the synchronous gear, reduce the gear shifting force and prolong the gear selecting time. By the method, the phenomenon that the rotation speed of the pre-selection gear shaft fluctuates too much in the pre-selection gear process can be avoided, and the problem of shaking abnormal sound is solved.

It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the invention, and any modification, combination, replacement, or improvement made within the spirit and principle of the present invention is included in the scope of the present invention.