KR20200103208A - Shift control method for vehicle with dct - Google Patents

Abstract

An objective of the present invention is to provide a shift control method of a DCT vehicle, which can improve the marketability of a vehicle. The shift control method of a DCT vehicle comprises: a release start step in which a controller starts releasing a release side clutch; a first initialization step of setting release side clutch torque calculated by using a release side clutch torque model as feed forward torque, and allowing the release side clutch torque to converge to the feed forward torque during a prescribed first reference time; a first feedback control step of calculating feedback torque in accordance with a clutch slip change rate when the first reference time elapses to control the release side clutch torque by the sum of the feed forward torque and the feedback torque; and a first torque handover step of increasing coupling side clutch torque to correspond to engine torque while releasing the release side clutch during a prescribed second reference time when performance preparation of a torque phase is determined to be completed while performing the first feedback control step.

Description

DCT vehicle shift control method {SHIFT CONTROL METHOD FOR VEHICLE WITH DCT}

The present invention is a technology related to shift control of a vehicle equipped with DCT (Dual Clutch Transmission).

Power On Downshift is a process in which the driver shifts to the target stage lower than the current stage while stepping on the accelerator pedal.

At this time, shifting is performed by sequentially performing an inertia phase and a torque phase.In the inertia phase, the release clutch starts to be released and the engine speed is connected to the current end. The torque phase is performed when the target end is separated from and rises toward the coupling-side clutch speed to which the target end is connected, and when the engine speed is synchronized with the coupling-side clutch speed, the torque of the coupling-side clutch is increased corresponding to the engine torque. At the same time, completely release the release clutch to complete the shift.

If the control for synchronizing the engine speed to the engagement-side clutch speed by increasing the engine speed from the release-side clutch speed in the inertia phase is stable and properly performed, the shift feeling is improved with smooth shifting.

The matters described as the background technology of the present invention are only for enhancing an understanding of the background of the present invention, and should not be taken as acknowledging that they correspond to the prior art already known to those of ordinary skill in the art. Will be

KR 1020150125756 A

The present invention provides a shift control method of a DCT vehicle that improves the sense of shift with a quick and smooth shift through a more stable and appropriate clutch control when a DCT-equipped vehicle performs a power-on-downshift, thereby ultimately improving the marketability of the vehicle. It has its purpose in providing.

The present invention DCT vehicle shift control method for achieving the above object,

A release start step of inducing an engine speed to rise above the release clutch speed by starting the release side clutch when the power-on downshift is started;

A first initialization step of setting the release-side clutch torque calculated by the controller using the release-side clutch torque model as a feed forward torque, and converging the release-side clutch torque to the feed-forward torque for a predetermined first reference time; and ;

A first feedback control step of calculating, by the controller, a feedback torque according to a clutch slip change rate when the first reference time elapses, and controlling the release clutch torque as a sum of the feed forward torque and the feedback torque;

During the execution of the first feedback control step, if the controller determines that the torque phase is ready to be performed, the release clutch is released for a predetermined second reference time and the engagement clutch torque is increased corresponding to the engine torque. A first talk handover step;

It characterized in that it is configured to include.

After the release start step and before the first initialization step, when it is determined that the difference between the engine speed and the release side clutch speed is equal to or greater than a predetermined first reference value, the controller adjusts a slope for reducing the release side clutch torque. It may be configured to further perform the rate of change adjustment step.

Prior to the first initialization step, the controller may be configured to further perform a shift type determination step of determining whether a biaxial shift or a coaxial shift is performed, and in the case of a biaxial shift, perform the first initialization step.

When the controller is in a coaxial shift situation as a result of performing the shift type determination step,

A second initialization step of setting the release-side clutch torque calculated by the controller using the release-side clutch torque model as a feed forward torque, and converging the release-side clutch torque to the feed-forward torque for a predetermined third reference time; and ;

A second feedback control step of calculating, by the controller, a feedback torque according to a clutch slip change rate, and controlling the release clutch torque as a sum of the feed forward torque and the feedback torque when the third reference time elapses;

During the execution of the second feedback control step, if the controller determines that the torque phase is ready to be performed, the release side clutch is released for a predetermined fourth reference time and the engagement side clutch torque is increased corresponding to the engine torque. A second talk handover step;

When the fourth reference time elapses, the controller switches the roles of the engagement-side clutch and the release-side clutch to each other, making the clutch that has been acting as the engagement-side clutch so far as the release-side clutch, and the torque of the release-side clutch A third feedback control step of controlling the feed forward torque calculated from the release-side clutch torque model and the sum of the feedback torque according to the clutch slip change rate;

During the execution of the third feedback control step, if the controller determines that the torque phase is ready to be performed, the release clutch is released for a predetermined fifth reference time, and the coupling-side clutch torque is increased corresponding to the engine torque. A third torque handover step;

It may be configured to further perform.

The release clutch torque model is the following equation,

; 해방측클러치 토크

; Release clutch torque

; 엔진토크

; Engine torque

; 엔진 관성모멘트

; Engine moment of inertia

Slip; Ne-Ni

Ne; Engine speed

Ni; Coupling side clutch rotation speed

; 구동계 관성에 기인한 토크

; Torque due to drive system inertia

It can be configured as

In the controller, the engagement of the target gear is completed while the first feedback control step is performed, the shift progress rate is equal to or greater than a predetermined second reference value, or the difference between the engine speed and the engagement side clutch speed is greater than or equal to the third reference value, and the engagement side clutch When the preparation for fastening of is completed, it may be configured to determine that the preparation for performing the torque phase is complete.

During the second feedback control step, the engagement of the target gear is completed, the shift progress rate is greater than or equal to a predetermined fourth reference value, or the difference between the engine speed and the engagement side clutch speed is greater than or equal to the fifth reference value, and the engagement side clutch When the preparation for fastening of is completed, it may be configured to determine that the preparation for performing the torque phase is complete.

During the third feedback control step, the engagement of the target gear is completed, the shift progress rate is equal to or greater than a predetermined sixth reference value, or the difference between the engine speed and the engagement side clutch speed is greater than or equal to the seventh reference value, and the engagement side clutch When the preparation for fastening of is completed, it may be configured to determine that the preparation for performing the torque phase is complete.

The feedback torque is calculated using a difference between a target clutch slip change rate and a measured clutch slip change rate calculated from a difference between the measured engine speed and the clutch speed;

The release-side clutch torque model for calculating the feedforward torque may be configured to use the target clutch slip change rate.

The present invention enables a DCT-equipped vehicle to improve the sense of shift through a more stable and appropriate clutch control when performing a power-on-downshift, and ultimately improve the marketability of the vehicle.

1 is a configuration diagram of a DCT-equipped vehicle to which the present invention can be applied,
2 is a flow chart showing an embodiment of a shift control method of a DCT vehicle according to the present invention;
3 is a block diagram illustrating a shift control method of the present invention.

1 is a configuration diagram of a DCT-equipped vehicle to which the present invention can be applied, wherein the power of the engine E is through a first clutch CL1 and a second clutch CL2, respectively, a first input shaft IN1 and a first input shaft of the DCT. 2 It is transmitted to the input shaft IN2 and shifted, and then supplied to the driving wheel W through the output shaft OUT.

In addition, a clutch actuator (CA) for driving the first clutch (CL1) and the second clutch (CL2), and a shift actuator (SA) for performing a shift with a selecting and shifting function are provided, and a controller (CLR) By being controlled by, it is configured to automatically shift.

The controller (CLR) receives the driver's accelerator pedal operation amount through the APS (Accelerator Position Sensor), and receives other information such as engine speed, torque, and vehicle speed, and receives the clutch actuator (CA) and the shift actuator (SA). It is configured to automatically change the DCT according to the driving situation of the vehicle by controlling the control.

Meanwhile, the engine is controlled by a separate EMS (Engine Management System), and the controller (CLR) communicates with the EMS to receive the engine information, and the engine is When requesting the EMS to adjust the torque of the EMS, the EMS is configured to control the engine in consideration of the request.

For reference, the controller (CLR) as described above may be configured as a TMS (Transmission Management System), and in some cases may be configured as an integrated control system in which the EMS and TMS are integrated.

Here, when the first clutch CL1 and the second clutch CL2 are shifted, one of the clutches is released while the other is engaged, and one of the two clutches is separated from the engine according to the shifting situation. The release side clutch to be used, the other is to be a coupling side clutch that is coupled to the engine.

Referring to FIG. 2, in an embodiment of the shift control method of a DCT vehicle according to the present invention, when the power-on and downshift is initiated, the controller initiates the release-side clutch release to induce the engine speed to increase above the release-side clutch speed. Step (S10) and; A first initialization step of setting the release-side clutch torque calculated by the controller using the release-side clutch torque model as a feed forward torque, and converging the release-side clutch torque to the feed-forward torque for a predetermined first reference time ( S40) and; When the first reference time elapses, the controller calculates a feedback torque according to the clutch slip change rate, and controls the release clutch torque as the sum of the feed forward torque and the feedback torque (S50). Wow; During the execution of the first feedback control step (S50), if the controller determines that the preparation of the torque phase is completed, the release clutch is released for a predetermined second reference time and the engagement clutch torque corresponds to the engine torque. It is configured to include a first torque handover step (S60) to increase the upward.

That is, in the embodiment of the present invention, when the power-on-downshift is initiated, the release-side clutch is firstly released to increase the engine speed away from the release-side clutch speed, and then the release-side clutch torque is reduced to the release-side clutch. By converging to the feed forward torque calculated through the torque model, and then controlling the release clutch torque according to the sum of the feed forward torque and the feedback torque, the power-on downshift inertia phase is appropriately fast and stable. By making it possible to control, it is possible to improve the shifting feeling of the vehicle.

In particular, as shown in Figure 3, the feedback torque is calculated by using the difference between the target clutch slip change rate and the measured clutch slip change rate calculated from the difference between the measured engine speed and the clutch speed, and calculates the feed forward torque. The release clutch torque model is configured to use the target clutch slip change rate, so that both the feed forward torque and the feedback torque are calculated using the target clutch slip change rate, which is the same physical quantity, thereby ensuring the consistency of control and This is to ensure adequate control.

On the other hand, in the embodiment of Figure 2, the present invention, after the release start step (S10) and before the first initialization step (S40), the controller has a difference between the engine speed and the release clutch speed is equal to or greater than a predetermined first reference value. If it is determined to be, it is configured to further perform a rate of change adjustment step (S20) of adjusting a slope for reducing the release clutch torque.

This is to set a different slope for reducing the torque of the release-side clutch in the release start step (S10) and the release-side clutch torque reduction slope after the difference between the engine speed and the release-side clutch speed becomes more than the first reference value. By doing so, it is possible to start a smoother inertia phase and to end the inertia phase more quickly.

That is, in the release start step (S10), the slope at which the release-side clutch torque starts to be reduced is relatively small, so that the engine is relatively gently separated from the release-side clutch, thereby enabling the initiation of a smooth inertia phase, and then the release. By making the reduction slope of the side clutch torque relatively large, the engine speed is increased more rapidly and the inertia phase can be terminated within a shorter time.

Accordingly, the first reference value may be determined design by experiment and analysis according to the above-described purpose, and may be set to 50 RPM, for example.

On the other hand, in this embodiment, before the first initialization step (S40), a shift type determination step (S30) for determining whether the controller is a biaxial shift or a coaxial shift is further performed, and in the case of a biaxial shift, the first initialization step ( S40) is performed, and as a result of performing the shift type determination step (S30), the following steps are additionally performed in the case of a coaxial shift situation.

That is, in the embodiment of the present invention, as a result of performing the shift type determination step (S30), in the case of a coaxial shift situation, the controller sets the release side clutch torque calculated using the release side clutch torque model as the feed forward torque, A second initialization step (S70) of converging the release clutch torque to the feed forward torque for a predetermined third reference time; When the third reference time elapses, the controller calculates a feedback torque according to the clutch slip change rate, and controls the release clutch torque as the sum of the feed forward torque and the feedback torque (S80). Wow; While performing the second feedback control step (S80), if the controller determines that the preparation of the torque phase is completed, the release clutch is released for a predetermined fourth reference time, and the engagement clutch torque corresponds to the engine torque. A second torque handover step (S90) of increasing the level; When the fourth reference time elapses, the controller switches the roles of the engagement-side clutch and the release-side clutch to each other, making the clutch that has been acting as the engagement-side clutch so far as the release-side clutch, and the torque of the release-side clutch A third feedback control step (S100) of controlling the sum of the feed forward torque calculated from the release clutch torque model and the feedback torque according to the clutch slip change rate; During the execution of the third feedback control step (S100), if the controller determines that the preparation of the torque phase is completed, the release clutch is released for a predetermined fifth reference time, and the engagement clutch torque corresponds to the engine torque. It is configured to further perform the third torque handover step (S110) to increase the level.

For reference, the first reference time and time may be set after completion of the change rate adjustment step (S20) or after completion of the shift type determination step (S30), and the length is the feed calculated by the release clutch torque model. According to the difference between the forward torque and the release clutch torque at the time point of the first reference time, the larger the difference may be configured to be obtained by a map or the like to ensure a longer time.

That is, the first reference time can be viewed as a time required for the release clutch torque to converge to the feed forward torque, so a map is provided in which a longer time is secured as the difference increases, and an appropriate It configures the time value to be selected.

In addition, the third reference time has almost the same technical meaning as the first reference time, and the third reference time is only used when the first reference time is a coaxial transmission, different from that used when the first reference time is a biaxial transmission. As for the first reference time, the time point may be set after the completion of the change rate adjustment step (S20) or after the completion of the shift type determination step (S30), and the release side clutch torque and release at this time It can be determined through a map or the like according to a difference in feed forward torque determined by the side clutch torque model.

The release clutch torque model can be expressed as Equation 1 below.

here,

; 해방측클러치 토크

; Release clutch torque

; 엔진토크

; Engine torque

; 엔진 관성모멘트

; Engine moment of inertia

Slip; Ne-Ni (= clutch slip)

Ne; Engine speed

Ni; Engagement side clutch rotation speed (= engagement side input shaft rotation number)

; 구동계 관성에 기인한 토크

; Torque due to drive system inertia

Meanwhile, the feedback torque is, as described above, using a clutch slip change rate error that is a difference between the target clutch slip change rate and the measured clutch slip change rate calculated from the difference between the measured engine speed and clutch speed, It can be configured to calculate the feedback torque by the same method as calculated by (Proportional Integral Derivative Control).

In the controller, while performing the first feedback control step (S50), the engagement of the target gear is completed, and the shift progress rate is equal to or greater than a predetermined second reference value, or the difference between the engine speed and the engagement side clutch speed is equal to or greater than a third reference value, When the preparation for fastening of the coupling side clutch is completed, it is configured to determine that the preparation for performing the torque phase is complete.

Here, the shift progress rate is calculated by Equation 2 below.

That is, the shift progress rate indicates how close the engine speed to the engagement clutch speed (= synchronous speed) from the release clutch speed.

Accordingly, the second reference value and the third reference value are set to values that can confirm that the engine speed is substantially close to the coupling side clutch speed, and the actual inertia phase ends. It can be determined by design.

In addition, the case where the preparation of the engagement side clutch is completed refers to a situation in which the engagement side clutch torque may be immediately generated when the engagement side clutch moves near the touch point and control is started. For example, the engagement side clutch torque is If it is more than -2Nm, it can be said that the preparation for fastening is complete.

For reference, the first initialization step (S40), the first feedback control step (S50), and the first torque handover step (S60) are steps performed during biaxial shifting. For example, in the shift type determination step (S30), [ This is a series of steps performed when the current stage-target stage <2 stage], that is, when the current stage is 4 stages and the target stage is 3 stages.

Therefore, while performing the first feedback control step (S50) as described above, when it is determined that the preparation for performing the torque phase is complete, the controller releases the release clutch and at the same time raises the engagement clutch to correspond to the engine torque. While performing a torque phase to finish shifting.

In this case, the controller controls to complete the torque phase during a predetermined second reference time, and the second reference time may be configured to use a preset value in consideration of vehicle speed and the like.

On the other hand, when it is determined in the shift type determination step (S30) that the difference between the current stage and the target stage is 2 stages, for example, when the current stage is 4 stages and the target stage is 2 stages, the second initialization step (S70), the second feedback control step (S80), the second torque handover step (S90), the third feedback control step (S100), and the third torque handover step (S110) are sequentially performed to complete the coaxial shift. It is supposed to be.

Hereinafter, it is assumed that the current stage is the 4th stage and the final target stage is the 2nd stage.

In the controller, while the second feedback control step (S80) is performed, the target gear is completely engaged, and the shift progress rate is greater than or equal to a predetermined fourth reference value, or the difference between the engine speed and the engagement side clutch speed is greater than or equal to a fifth reference value, When the preparation for fastening of the coupling side clutch is completed, it is configured to determine that the preparation for performing the torque phase is complete.

In this case, the target gear refers to a gear of the third gear. In other words, coaxial shifting is performed in a manner in which shifting from 4th to 3rd and shifting from 3rd to 2nd is carried out in succession.In this step, the target gear is first set to 3rd and the 3rd gear is engaged. It is to determine whether the talk phase is ready to be performed.

Similar to the second and third reference values, the fourth and fifth reference values are substantially close to the coupling-side clutch speed (= synchronous speed), and thus it can be confirmed that the actual inertia phase ends. As the values are set, they can be determined by design through a number of experiments and analysis.

During the execution of the second feedback control step (S80), when it is determined that the preparation of the torque phase is completed, the controller performs the torque phase for a predetermined fourth reference time.

Here, the fourth reference time, like the second reference time, is configured to use a preset value in consideration of vehicle speed and the like.

As a result, the DCT is in a state in which the shift to the third gear is substantially completed, and the shift to the second gear is carried out immediately. As described above, the clutch that has served as the engagement side clutch until now becomes the release side clutch. In addition, the clutch that used to serve as the release side clutch becomes the engagement side clutch.

After the role of the clutches is switched as described above, the third feedback control step (S100) is performed, and the controller completes the engagement of the target gear while performing the third feedback control step (S100), and the shift progress rate When the predetermined sixth reference value or more or the difference between the engine speed and the engagement-side clutch speed is greater than or equal to the seventh reference value, and the preparation for fastening of the engagement-side clutch is completed, it is determined that the preparation of the torque phase is completed.

In this case, the target gear refers to a second gear, and the sixth reference value and the seventh reference value are substantially close to the coupling side clutch speed (= synchronous speed) like the second reference value or the third reference value. , As values that can confirm that the actual inertia phase has ended, and can be determined by design through a number of experiments and analysis.

When the controller determines that the preparation for torque phase execution is complete while performing the third feedback control step (S100), the controller releases the release clutch for a fifth reference time and increases the engagement clutch to correspond to the engine torque. Perform a torque phase to end shifting.

Here, the fifth reference time is also configured to use a preset value in consideration of vehicle speed and the like.

Although the present invention has been shown and described in connection with specific embodiments, it is understood in the art that the present invention can be variously improved and changed within the scope of the technical spirit of the present invention provided by the following claims. It will be obvious to a person of ordinary knowledge.

E; engine
CL1; 1st clutch
CL2; 2nd clutch
IN1; 1st input axis
IN2; 2nd input shaft
OUT; Output shaft
W; Drive wheel
CA; Clutch actuator
SA; Variable speed actuator
CLR; controller
S10; Release start stage
S40; 1st initialization step
S50; The first feedback control step
S60; 1st torque handover phase
S20; Change rate adjustment stage
S30; Shift type judgment step
S70; 2nd initialization step
S80; 2nd feedback control step
S90; Second torque handover step
S100; 3rd feedback control step
S110; 3rd torque handover step

Claims (9)

A release start step of inducing an engine speed to rise above the release clutch speed by starting the release side clutch when the power-on downshift is started;
A first initialization step of setting the release-side clutch torque calculated by the controller using the release-side clutch torque model as a feed forward torque, and converging the release-side clutch torque to the feed-forward torque for a predetermined first reference time; and ;
A first feedback control step of calculating, by the controller, a feedback torque according to a clutch slip change rate when the first reference time elapses, and controlling the release clutch torque as a sum of the feed forward torque and the feedback torque;
During the execution of the first feedback control step, if the controller determines that the torque phase is ready to be performed, the release clutch is released for a predetermined second reference time and the engagement clutch torque is increased corresponding to the engine torque. A first talk handover step;
DCT vehicle shift control method, characterized in that configured to include. The method according to claim 1,
After the release start step and before the first initialization step, when it is determined that the difference between the engine speed and the release side clutch speed is equal to or greater than a predetermined first reference value, the controller adjusts a slope for reducing the release side clutch torque. Configured to further carry out rate-of-change adjustment steps
DCT vehicle shift control method, characterized in that. The method according to claim 1,
Before the first initializing step, the controller further performs a shift type determination step of determining whether a biaxial shift or a coaxial shift is performed, and in the case of a biaxial shift, the first initialization step is performed.
DCT vehicle shift control method, characterized in that. The method of claim 3,
When the controller is in a coaxial shift situation as a result of performing the shift type determination step,
A second initialization step of setting the release-side clutch torque calculated by the controller using the release-side clutch torque model as a feed forward torque, and converging the release-side clutch torque to the feed-forward torque for a predetermined third reference time; and ;
A second feedback control step of calculating, by the controller, a feedback torque according to a clutch slip change rate, and controlling the release clutch torque as a sum of the feed forward torque and the feedback torque when the third reference time elapses;
During the execution of the second feedback control step, if the controller determines that the torque phase is ready to be performed, the release side clutch is released for a predetermined fourth reference time and the engagement side clutch torque is increased corresponding to the engine torque. A second talk handover step;
When the fourth reference time elapses, the controller switches the roles of the engagement-side clutch and the release-side clutch to each other, making the clutch that has been acting as the engagement-side clutch so far as the release-side clutch, and the torque of the release-side clutch A third feedback control step of controlling the feed forward torque calculated from the release-side clutch torque model and the sum of the feedback torque according to the clutch slip change rate;
During the execution of the third feedback control step, if the controller determines that the torque phase is ready to be performed, the release clutch is released for a predetermined fifth reference time, and the coupling-side clutch torque is increased corresponding to the engine torque. A third torque handover step;
DCT vehicle shift control method, characterized in that configured to perform further. The method according to claim 1,
The release clutch torque model is the following equation,

; Release clutch torque

; Engine torque

; Engine moment of inertia
Slip; Ne-Ni
Ne; Engine speed
Ni; Coupling side clutch rotation speed

; Torque due to drive system inertia
DCT vehicle shift control method, characterized in that configured as. The method according to claim 1,
In the controller, the engagement of the target gear is completed while the first feedback control step is performed, the shift progress rate is equal to or greater than a predetermined second reference value, or the difference between the engine speed and the engagement side clutch speed is greater than or equal to the third reference value, and the engagement side clutch It is configured to judge that the preparation for the execution of the torque phase is completed when the preparation for the tightening is completed.
DCT vehicle shift control method, characterized in that. The method of claim 4,
During the second feedback control step, the engagement of the target gear is completed, the shift progress rate is greater than or equal to a predetermined fourth reference value, or the difference between the engine speed and the engagement side clutch speed is greater than or equal to the fifth reference value, and the engagement side clutch It is configured to judge that the preparation for the execution of the torque phase is completed when the preparation for the tightening is completed.
DCT vehicle shift control method, characterized in that. The method of claim 4,
During the third feedback control step, the engagement of the target gear is completed, the shift progress rate is equal to or greater than a predetermined sixth reference value, or the difference between the engine speed and the engagement side clutch speed is greater than or equal to the seventh reference value, and the engagement side clutch It is configured to judge that the preparation for the execution of the torque phase is completed when the preparation for the tightening is completed.
DCT vehicle shift control method, characterized in that. The method according to claim 1,
The feedback torque is calculated using a difference between a target clutch slip change rate and a measured clutch slip change rate calculated from a difference between the measured engine speed and the clutch speed;
The release clutch torque model for calculating the feedforward torque is configured to use the target clutch slip change rate.
DCT vehicle shift control method, characterized in that.

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