CN109372982B

CN109372982B - Control method for power upshift and rotation speed synchronization of wet-type double-clutch automatic transmission

Info

Publication number: CN109372982B
Application number: CN201811613284.6A
Authority: CN
Inventors: 刘小龙; 黄辉; 韩涌波; 向光军; 蒋平; 胡显力
Original assignee: Chongqing Changan Automobile Co Ltd
Current assignee: Chongqing Changan Automobile Co Ltd
Priority date: 2018-12-27
Filing date: 2018-12-27
Publication date: 2020-09-08
Anticipated expiration: 2038-12-27
Also published as: CN109372982A

Abstract

The invention provides a control method for power upshift and rotation speed synchronization of a wet double-clutch automatic transmission, which subdivides a rotation speed synchronization stage in a power upshift process into a rotation speed disengagement stage, a rotation speed closed-loop control stage and a recovery stage in detail, improves the control method of each stage, realizes better clutch combination when controlling rotation speed synchronization, simultaneously accurately controls torque requests of an engine, and avoids impact generated when rotating speeds are synchronized to the maximum extent.

Description

Control method for power upshift and rotation speed synchronization of wet-type double-clutch automatic transmission

Technical Field

The invention belongs to the gear shifting control technology of an automobile automatic transmission, and particularly relates to a gear shifting control technology of a wet double-clutch automatic transmission (DCT for short).

Background

At present, vehicles carrying automatic transmissions are increasingly popularized, the requirements of consumers on the shifting quality of the automatic transmissions are also increasingly high, the existing double-clutch automatic transmission shifting quality calibration and matching technology is mostly mastered in foreign host factories, the double-clutch automatic transmissions independently researched and developed in China mostly have the problems of shifting, pause, impact and the like in different degrees, and the requirements of the consumers on the shifting quality cannot be met.

Because the control logic of the power upshift of the foreign automatic transmission cannot be known, the initial rough analysis can be only carried out on the cracked partial signals, and the problem of gear shifting impact and the like exist in the gear shifting process of a vehicle carrying the double-clutch automatic transmission. FIG. 1 shows data of a power upshift speed synchronization stage of a dual clutch automatic transmission vehicle, and the data are analyzed, so that the separation of a separation clutch is fast in the initial stage of speed synchronization, and the shaking occurs when the rotation speed of an input shaft is separated from the rotation speed of an engine; in the middle section of the rotating speed reduction, the slope of the rotating speed of the engine is obviously segmented, and acceleration fluctuation occurs; in the rotating speed synchronization stage, the long synchronization time causes long-time sliding abrasion of the clutch. It can be seen that there is room for optimization at this stage, both logically and nominally.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a control method for power upshift and rotation speed synchronization of a wet double-clutch automatic transmission, which subdivides rotation speed synchronization stages in the power upshift process in detail, improves the control method of each stage, better controls clutch combination during rotation speed synchronization, simultaneously accurately controls the torque request of an engine, and avoids impact generated during rotation speed synchronization to the maximum extent.

The technical scheme of the invention is as follows:

a control method for power upshift and rotation speed synchronization of a wet double-clutch automatic transmission comprises the following steps:

1. and (3) a rotating speed disengaging stage: the engine speed and the separating shaft speed are separated, and the engine speed and the separating shaft speed start to fall until the engine speed and the separating shaft speed are synchronous with the rotating speed of the combining shaft;

1.1, calculating a first target clutch torque through the opening degree of an accelerator, the current gear and the actual change rate of the rotating speed of the engine;

1.2, the engine torque request varies with a variation in engine torque without a TCU request;

1.3, when the rotating speed of the engine is lower than a certain rotating speed value A of the separating shaft, carrying out rotating speed closed-loop control; the fixed value A is controlled within 200rpm and is obtained by calibration.

2. A rotating speed closed-loop control stage: the torque of the clutch is controlled through a PID module, and continuous synchronization of the rotating speed is realized by matching with torque reduction;

2.1, calculating target rotating speed phase time through the opening degree of an accelerator and a target gear; calculating a target engine speed and an engine torque reduction target value through the target speed phase time, the actual engine speed, the separation shaft speed and the combined shaft speed; calculating a clutch feed forward torque from the engine torque without the TCU request;

2.2, sending an engine torque reduction request and adjusting an engine torque reduction target value in real time according to the engine torque without the TCU request;

and 2.3, the PID module calculates a second target clutch torque through the actual engine speed, the target engine speed, the accelerator opening, the target gear and the like, and compensates the second target clutch torque according to the clutch feedforward torque so as to respond to the change of the driver demand in real time and increase the system robustness.

And 2.4, calculating the time for entering the recovery phase through the opening degree of the accelerator, the target gear, the actual engine rotating speed and the combined shaft rotating speed.

3. And (3) a recovery stage: the engine torque request is recovered, and the engine rotating speed and the rotating speed of the combined shaft are controlled to be smoothly synchronized by combining the clutch;

3.1, calculating a torque reduction value according to the actual engine speed, the engine speed at the time of entering a recovery phase and the combined shaft speed, and completely recovering the engine torque to the value required by a driver when the actual engine speed and the combined shaft speed are synchronous;

3.2, calculating a final target clutch torque value through the engine torque and the target gear; and calculating the current target clutch torque through the final target clutch torque value, the accelerator opening and the current gear, and compensating the current target clutch torque according to the clutch feedforward torque.

According to the control method, each sub-stage of the double-clutch power upshift and rotation speed synchronization is accurately controlled, so that the impact generated in the rotation speed synchronization stage is effectively solved, and the driving feeling of a vehicle carrying the wet double-clutch transmission is improved.

Drawings

FIG. 1 is a data diagram of a power upshift speed synchronization phase of a dual clutch automatic transmission vehicle;

FIG. 2 is a schematic diagram of a power upshift speed synchronization phase of a dual clutch automatic transmission;

FIG. 3 is a diagram illustrating the calibration effect of the present invention;

fig. 4 is a control logic diagram of the present invention.

Detailed Description

The invention is described in further detail below with reference to the accompanying drawings:

the power upshift speed phase control aims to realize the reduction of the engine speed from the separation clutch speed to the synchronization with the combination clutch speed. In order to realize the rotation speed synchronization quickly and stably, the invention is realized by matching the engine torque request with the clutch torque control. Control involving mainly two large panels

1. Clutch control

The clutch control method is used for controlling the engine speed to switch from the separating shaft to the combining shaft with a certain gradient. The clutch is engaged using a profile control during a power upshift. The curve control is carried out by the following stages:

TABLE 1 rotational speed phase PID Curve control

2. Engine torque request

The engine torque request control controls engine torque down during a power upshift. Engine torque request control has three phases: the initial phase is maintained until the engine speed and the shaft speed are separated. The torque target is a fixed value (for torque drop, a percentage of engine torque without TCU request) that is controlled to reach the target with a slope. The final engine torque target is the percentage of engine torque requested without the TCU and the control to target is done at a fixed time rather than a fixed slope. The engine torque request for each program cycle is calculated from the remaining synchronization time and the difference between the current request and the final torque target. The engine torque ramp rate has a maximum limit value per program cycle to prevent jerks.

Based on the above thought, referring to fig. 4, the invention designs the following control method for power upshift and rotation speed synchronization of the wet double clutch automatic transmission. The control logic belongs to the sub-state of a clutch control plate in the gear shifting process under the working condition of power gear-up, and the following rotating speed phase stage is entered after the clutch torque switching process is completed:

first, the disengagement phase of the rotation speed-part a of fig. 2: this phase achieves disengagement of the engine speed and the disconnect shaft speed and begins to drop until synchronized with the engage shaft speed.

1. A first target clutch torque is calculated through the accelerator opening, the current gear and the actual engine speed change rate.

2. The engine torque request varies as a function of engine torque without a TCU request.

3. And when the actual engine rotating speed is lower than the rotating speed of the separation shaft by a certain value, the closed-loop control of the rotating speed is carried out.

Second, the rotation speed closed-loop control stage-the stage B part of fig. 2: in the stage, the clutch torque is controlled through the PID module, and continuous synchronization of the rotating speed is realized by matching with torque reduction.

1. And calculating the target rotating speed phase time through the opening degree of the accelerator and the target gear. And calculating a target engine speed and an engine torque reduction target value through the target speed phase time, the actual engine speed, the separating shaft speed and the combined shaft speed. The clutch feed forward torque is calculated from the engine torque without the TCU request.

2. An engine torque down request is sent and a torque down target value is adjusted in real time based on the engine torque without the TCU request.

3. The PID module calculates a second target clutch torque through the actual engine speed, the target engine speed, the accelerator opening, the target gear and the like. And the second target clutch torque is compensated according to the clutch feedforward torque so as to respond to the change of the requirement of the driver in real time and increase the robustness of the system.

4. And calculating the time for entering the recovery stage according to the accelerator opening, the target gear, the actual engine rotating speed and the combined shaft rotating speed.

Third, recovery phase-fig. 2 phase C part: the engine torque request is restored and the engine speed is controlled in conjunction with the clutch to smoothly synchronize with the shaft speed.

1. And calculating the torque reduction value according to the actual engine speed, the engine speed at the moment of entering the recovery phase and the combined shaft speed, so that the torque of the engine is completely recovered to the value required by a driver when the actual engine speed and the combined shaft speed are synchronous.

2. A final target clutch torque value is calculated from the engine torque and the target gear. And calculating the current target clutch torque through the final target clutch torque value, the accelerator opening and the current gear. And compensating the current target clutch torque according to the clutch feedforward torque.

And finally, exiting the rotating speed phase stage.

While a specific example is given above, it will be appreciated by those skilled in the art that: other control schemes can still be converted by modifying the technical scheme provided by the embodiment or replacing part of technical features of the technical scheme; the modifications and the substitutions of the system scheme of the invention do not make the essence of the corresponding technical scheme depart from the spirit and the scope of the technical scheme of the embodiments of the invention.

Claims

1. A control method for power upshift and rotation speed synchronization of a wet double clutch automatic transmission is characterized by comprising the following steps:

(1) and (3) a rotating speed disengaging stage: the engine speed and the separating shaft speed are separated, and the engine speed and the separating shaft speed start to fall until the engine speed and the separating shaft speed are synchronous with the rotating speed of the combining shaft;

(1.1) calculating a first target clutch torque according to the opening degree of an accelerator, the current gear and the actual change rate of the rotating speed of the engine;

(1.2) the engine torque request varies with a variation in engine torque without a TCU request;

(1.3) when the actual engine rotating speed is lower than the rotating speed of the separating shaft by a certain value A, entering rotating speed closed-loop control;

(2) a rotating speed closed-loop control stage: the torque of the clutch is controlled through a PID module, and continuous synchronization of the rotating speed is realized by matching with torque reduction;

(2.1) calculating target rotating speed phase time through the opening degree of an accelerator and a target gear; calculating a target engine speed and an engine torque reduction target value through the target speed phase time, the actual engine speed, the separation shaft speed and the combined shaft speed; calculating a clutch feed forward torque from the engine torque without the TCU request;

(2.2) sending an engine torque reduction request and adjusting an engine torque reduction target value in real time according to the engine torque without the TCU request;

(2.3) the PID module calculates a second target clutch torque through the actual engine speed, the target engine speed, the accelerator opening and the target gear, and compensates the second target clutch torque according to the clutch feedforward torque so as to respond to the change of the driver demand in real time and increase the system robustness;

(2.4) calculating the time for entering the recovery stage according to the opening degree of the accelerator, the target gear, the actual engine rotating speed and the combined shaft rotating speed;

(3) and (3) a recovery stage: the engine torque request is recovered, and the actual engine rotating speed and the rotating speed of the combined shaft are controlled to be smoothly synchronized by combining the clutch;

(3.1) calculating the torque reduction target value of the engine according to the actual engine speed, the engine speed at the time of entering the recovery phase and the combined shaft speed, and completely recovering the engine torque to the required value of a driver when the actual engine speed and the combined shaft speed are synchronous;

(3.2) calculating a final target clutch torque value from the engine torque and the target gear; and calculating the current target clutch torque through the final target clutch torque value, the accelerator opening and the current gear, and compensating the current target clutch torque according to the clutch feedforward torque.

2. The control method for synchronizing the power upshifting speed of the wet double clutch automatic transmission according to claim 1, characterized in that the certain value A is controlled within 200rpm and is obtained by calibration.

3. The control method for synchronizing power upshift speeds of a wet dual clutch automatic transmission according to claim 1, wherein in said speed disengagement phase, the control target is an initial slope to separate the actual engine speed from the disconnect shaft speed.

4. A control method of power upshift speed synchronization of a wet dual clutch automatic transmission according to claim 1, characterized in that in said speed closed loop control phase, the control target is that clutch torque is adjusted by PID so that actual engine speed follows a target slope and is transferred from the split shaft to the coupling shaft.

5. The control method for power upshift speed synchronization of a wet dual clutch automatic transmission according to claim 1, wherein said control target of the recovery phase is a small slope such that the engine speed is close to the joint shaft speed.