KR102588930B1 - Shift control method for vehicle with dct - Google Patents

Abstract

The present invention includes a release initiation step in which the controller initiates release of the release side clutch; A first initialization step of setting the release-side clutch torque calculated using the release-side clutch torque model as a feedforward torque, and converging the release-side clutch torque to the feedforward torque for a predetermined first reference time; When the first reference time elapses, a first feedback control step of calculating a feedback torque according to the clutch slip change rate and controlling the release-side clutch torque as the sum of the feedforward torque and the feedback torque; While performing the first feedback control step, when it is determined that preparation for the torque phase is completed, the release side clutch is released for a predetermined second reference time and the first torque is increased to increase the engagement side clutch torque corresponding to the engine torque. It consists of a handover step.

Description

Shift control method for DCT vehicles {SHIFT CONTROL METHOD FOR VEHICLE WITH DCT}

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

Power On Downshift is the process of shifting gears to a target gear lower than the current gear while the driver presses the accelerator pedal.

At this time, shifting is accomplished by sequentially performing the inertia phase and the torque phase. In the inertia phase, the disengaging side clutch is started to be released, and the engine speed is equal to the disengaging side clutch speed connected to the current stage. It deviates from the target stage and rises toward the coupled clutch speed, and when the engine speed is synchronized with the coupled clutch speed, the torque phase is performed, while increasing the torque of the coupled clutch in accordance with the engine torque. At the same time, completely release the release side clutch to complete shifting.

If the control of increasing the engine speed from the disengaging side clutch speed and synchronizing it with the engaging side clutch speed in the inertia phase is performed stably and appropriately, the shifting feeling is improved with smooth shifting.

The matters described as the background technology of the above invention are only for the purpose of improving the understanding of the background of the present invention, and should not be taken as recognition that they correspond to prior art already known to those skilled in the art. It will be.

KR 1020150125756 A

The present invention provides a shift control method for a DCT vehicle that ultimately improves the marketability of the vehicle by improving the shifting feel through quick and smooth shifting through more stable and appropriate clutch control when the DCT-equipped vehicle performs power-on downshifting. The purpose is to provide.

The shift control method of the present invention DCT vehicle to achieve the above-mentioned purpose is,

When the power-on downshift is initiated, a release start step in which the controller initiates release of the release-side clutch to induce the engine speed to rise above the release-side clutch speed;

A first initialization step in which the controller sets the release-side clutch torque calculated using the release-side clutch torque model as a feedforward torque, and converges the release-side clutch torque to the feedforward torque for a predetermined first reference time; ;

When the first reference time elapses, a first feedback control step in which the controller calculates a feedback torque according to the clutch slip change rate and controls the release-side clutch torque as the sum of the feedforward torque and the feedback torque;

During the first feedback control step, when the controller determines that the torque phase is ready, the release side clutch is released for a predetermined second reference time and the engagement side clutch torque is increased corresponding to the engine torque. First talk handover step;

It is characterized by being composed including.

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

Before the first initialization step, the controller may be configured to further perform a shift type determination step to determine whether it is biaxial shifting or coaxial shifting, and in the case of biaxial shifting, perform the first initialization step.

If the controller performs the shift type determination step and is in a coaxial shift situation,

A second initialization step in which the controller sets the release-side clutch torque calculated using the release-side clutch torque model as a feedforward torque, and converges the release-side clutch torque to the feedforward torque for a predetermined third reference time; ;

When the third reference time elapses, a second feedback control step in which the controller calculates a feedback torque according to the clutch slip change rate and controls the release-side clutch torque as the sum of the feedforward torque and the feedback torque;

During the second feedback control step, when the controller determines that the torque phase is ready, 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 has elapsed, the controller switches the roles of the engaging side clutch and the disengaging side clutch, so that the clutch that has so far acted as the engaging side clutch becomes the disengaging side clutch, and the torque of this disengaging side clutch is changed. A third feedback control step of controlling by the sum of the feed forward torque calculated from the release side clutch torque model and the feedback torque according to the clutch slip change rate;

During the third feedback control step, when the controller determines that the torque phase is ready, the release side clutch is released for a predetermined fifth reference time and the engagement side clutch torque is increased corresponding to the engine torque. Third talk handover step;

It may be configured to further perform.

The release side clutch torque model is the following formula,

; Release side clutch torque

; engine torque

; Engine moment of inertia

Slip; Ne-Ni

Ne; engine speed

Ni; Combined clutch rotation speed

; Torque due to drivetrain inertia

It can be configured as follows.

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

While performing the second feedback control step, the controller completes engagement of the target gear, 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 the fifth reference value, and the engagement side clutch When preparations for the engagement are completed, it may be configured to determine that preparations for performing the torque phase are complete.

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

The feedback torque is calculated 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 clutch speed;

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

The present invention improves the shifting feel through quick and smooth shifting through more stable and appropriate clutch control when a DCT-equipped vehicle performs a power-on downshift, ultimately improving the marketability of the vehicle.

1 is a configuration diagram of a DCT-equipped vehicle to which the present invention can be applied;
Figure 2 is a flowchart showing an embodiment of a shift control method for a DCT vehicle according to the present invention;
Figure 3 is a block diagram explaining the 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, in which the power of the engine E is transmitted to the first input shaft IN1 and the second input shaft IN1 of the DCT through the first clutch CL1 and the second clutch CL2, respectively. 2 It is transmitted to the input shaft (IN2), shifted, and then supplied to the drive 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 shifting with a selecting and shifting function are provided, and the controller (CLR) Controlled by , it is configured to automatically shift gears.

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

Meanwhile, the engine is controlled by a separate EMS (Engine Management System), and the controller (CLR) can receive information about the engine by communicating with the EMS, and operates the engine according to the driving situation and shifting situation of the vehicle. When the EMS is requested 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 Transmission Management System (TMS), and in some cases, it may be configured as an integrated control system that integrates the EMS and TMS.

Here, when the first clutch (CL1) and the second clutch (CL2) shift, one is released and the other is engaged, and depending on the shift situation, one of the two clutches is disconnected from the engine. One is the release side clutch, and the other is the engagement side clutch that is coupled to the engine.

Referring to FIG. 2, in an embodiment of the shift control method for a DCT vehicle of the present invention, when the power-on downshift is initiated, the controller initiates release of the release side clutch to induce the engine speed to rise above the release side clutch speed. Step (S10) and; A first initialization step in which the controller sets the release-side clutch torque calculated using the release-side clutch torque model as a feedforward torque, and converges the release-side clutch torque to the feedforward torque for a predetermined first reference time ( S40) and; When the first reference time elapses, a first feedback control step (S50) in which the controller calculates a feedback torque according to the clutch slip change rate and controls the release side clutch torque as the sum of the feed forward torque and the feedback torque. and; While performing the first feedback control step (S50), when the controller determines that the torque phase is ready, the release side clutch is released for a predetermined second reference time and the engagement side clutch torque is adjusted to correspond to the engine torque. It is configured to include a first torque handover step (S60) to increase the torque.

That is, in the embodiment of the present invention, when the power-on downshift is initiated, the release side clutch is first initiated to allow the engine speed to rise deviating from the release side clutch speed, and then the release side clutch torque is transferred to the release side clutch. It converges to the feedforward torque calculated through the torque model, and then controls the release-side clutch torque according to the sum of the feedforward torque and the feedback torque, so that the power-on downshift inertia phase is properly controlled in a quick and stable state. By providing control, it is possible to improve the shifting feel of the vehicle.

In particular, as shown in FIG. 3, the feedback torque is calculated 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 clutch speed, and the feedforward torque is calculated. The release-side clutch torque model is configured to use the target clutch slip change rate, so that both the feedforward torque and the feedback torque are calculated using the target clutch slip change rate, which is the same physical quantity, so that control consistency is ensured and the release-side clutch This is to ensure appropriate control.

Meanwhile, in the embodiment of FIG. 2, the present invention is such that after the release start step (S10) and before the first initialization step (S40), the controller determines that the difference between the engine speed and the release side clutch speed is greater than or equal to a predetermined first reference value. If it is determined that this is the case, a change rate adjustment step (S20) of adjusting the slope to reduce the release side clutch torque is further performed.

This means that the slope at which the torque of the release side clutch begins to be reduced in the release start step (S10) and the slope of the release side clutch torque reduction after the difference between the engine speed and the release side clutch speed becomes more than the first reference value are set to be different. By doing so, it is possible to achieve a smoother start of the inertia phase and a more rapid end of the inertia phase.

That is, in the release start step (S10), the slope at which the release-side clutch torque begins to be reduced is relatively small so that the engine is spaced relatively gently from the release-side clutch, thereby enabling a smooth start of the inertia phase, and then the release-side clutch. By making the reduction slope of the side clutch torque relatively large, the engine speed can increase more quickly, making it possible to end the inertia phase in a shorter time.

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

Meanwhile, in this embodiment, before the first initialization step (S40), the controller further performs a shift type determination step (S30) to determine whether the controller is biaxial shifting or coaxial shifting, and in the case of biaxial shifting, the first initialization step ( S40) is performed, and if, as a result of performing the shift type determination step (S30), it is a coaxial shift situation, the following steps are additionally performed.

That is, in an embodiment of the present invention, when the shift type determination step (S30) is performed and a coaxial shift situation is in effect, the controller sets the release-side clutch torque calculated using the release-side clutch torque model as the feedforward torque, a second initialization step (S70) of converging the release-side clutch torque to the feedforward torque for a predetermined third reference time; When the third reference time elapses, a second feedback control step (S80) in which the controller calculates a feedback torque according to the clutch slip change rate and controls the release side clutch torque as the sum of the feed forward torque and the feedback torque. and; While performing the second feedback control step (S80), when the controller determines that the torque phase is ready, the release side clutch is released for a predetermined fourth reference time and the engagement side clutch torque is adjusted to correspond to the engine torque. a second torque handover step (S90) of increasing the torque; When the fourth reference time has elapsed, the controller switches the roles of the engaging side clutch and the disengaging side clutch, so that the clutch that has so far acted as the engaging side clutch becomes the disengaging side clutch, and the torque of this disengaging side clutch is changed. A third feedback control step (S100) of controlling by the sum of the feed forward torque calculated from the release side clutch torque model and the feedback torque according to the clutch slip change rate; During the third feedback control step (S100), when the controller determines that the torque phase is ready, the release side clutch is released for a predetermined fifth reference time and the engagement side clutch torque is adjusted to correspond to the engine torque. It is configured to further perform a third torque handover step (S110) to increase the torque.

For reference, the first reference time and point can 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 side clutch torque model. Depending on the difference between the forward torque and the release-side clutch torque at the time of the first reference time, it can be configured to be obtained by a map such that the larger the difference, the longer the time is secured.

That is, the first reference time can be viewed as the time required for the release-side clutch torque to converge to the feedforward torque, so a map is provided in which a longer time is secured as the difference becomes larger, and an appropriate time is provided according to the difference. This 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 in the case of coaxial shifting, distinguishing it from the first reference time used in the case of biaxial shifting. In order to do so, like the first reference time, the time point can be set after completion of the change rate adjustment step (S20) or after completion of the shift type judgment step (S30), and the release side clutch torque and release at this point It can be determined through a map based on the difference in feedforward torque determined by the side clutch torque model.

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

here,

; Release side clutch torque

; engine torque

; Engine moment of inertia

Slip; Ne-Ni (=clutch slip)

Ne; engine speed

Ni; Coupled side clutch rotation speed (=engaged side input shaft rotation speed)

; Torque due to drivetrain inertia

Meanwhile, as described above, the feedback torque is generated using a conventionally known PID control using a clutch slip change rate error, which is 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. It can be configured to calculate the feedback torque using the same method as calculating it by (Proportional Integral Derivative Control).

While performing the first feedback control step (S50), the controller completes engagement of the target gear, the shift progress rate is greater than or equal to 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, When preparations for engaging the engagement side clutch are completed, it is determined that preparations for performing the torque phase are completed.

Here, the shift progress rate is calculated by the following equation 2.

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

Therefore, the second and third reference values are set to values that can confirm that the engine speed is substantially close to the engagement side clutch speed and the actual end point of the inertia phase has been reached, based on numerous experiments and analyses. It can be decided by design.

In addition, the case where the engagement side clutch is ready to engage refers to a situation in which the engagement side clutch torque can be generated immediately when the engagement side clutch is moved near the touch point and control is initiated. For example, the engagement side clutch torque is If it is more than -2Nm, preparation for fastening can be considered 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 in the case of [current stage - target stage < 2 stages], that is, when the current stage is stage 4 and the target stage is stage 3.

Therefore, when it is determined that preparation for the torque phase is completed while performing the first feedback control step (S50) as described above, the controller releases the release side clutch and simultaneously raises the engagement side clutch to correspond to the engine torque. While doing so, perform the torque phase to complete the shift.

At this time, the controller controls the torque phase to be completed during a predetermined second reference time, and this second reference time can be configured to use a preset value in consideration of vehicle speed, etc.

On the other hand, when it is determined that coaxial shifting is performed in the shift type determination step (S30), that is, 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 performed sequentially to complete the coaxial shift. It is supposed to be done.

Hereinafter, the description will be made assuming that the current stage is stage 4 and the final target stage is stage 2.

While performing the second feedback control step (S80), the controller completes engagement of the target gear, 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, When preparations for engaging the engagement side clutch are completed, it is determined that preparations for performing the torque phase are completed.

In this case, the target gear refers to the third gear. In other words, coaxial shifting is performed in a way that shifting from 4th gear to 3rd gear and shifting from 3rd gear to 2nd gear are performed sequentially. In this step, the target gear is first set to 3rd gear and the gear shift is determined by whether the 3rd gear is engaged. This is to determine whether the talk phase is ready to be performed.

As with the second and third reference values, the fourth and fifth reference values can be confirmed that the engine speed is substantially close to the engagement side clutch speed (= synchronous speed), which is the actual end point of the inertia phase. It is set to certain values and can be determined by design through multiple experiments and analysis.

If the controller determines that the preparation for the torque phase is complete while performing the second feedback control step (S80), it 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, etc.

As a result, the DCT has almost completed shifting to 3rd gear, and immediately thereafter shifts to 2nd gear. As described above, the clutch that has served as the engaging side clutch becomes the disengaging side clutch. , the clutch that served as the release side clutch becomes the engagement side clutch.

After the roles of the clutches are 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 is If the predetermined sixth standard value is greater than or the difference between the engine speed and the engagement side clutch speed is greater than the seventh standard value, and preparations for engaging the engagement side clutch are completed, it is determined that preparations for performing the torque phase are completed.

In this case, the target gear refers to the 2nd gear, and the 6th and 7th reference values, like the 2nd and 3rd reference values, are substantially close to the engagement side clutch speed (= synchronous speed). , These are values that confirm that the actual end point of the inertia phase has arrived, and can be determined by design through multiple experiments and analysis.

During the third feedback control step (S100), when the controller determines that preparation for the torque phase is complete, the controller releases the release side clutch during the fifth reference time and simultaneously raises the engagement side clutch to correspond to the engine torque. Perform the torque phase to end the shift.

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

Although the present invention has been shown and described in relation to specific embodiments, it is known in the art that various improvements and changes can be made to the present invention without departing from the technical spirit of the invention as provided by the following claims. This will be self-evident to those with ordinary knowledge.

E; engine
CL1; 1st clutch
CL2; 2nd clutch
IN1; 1st input axis
IN2; 2nd input axis
OUT; output shaft
W; driving wheel
CA; Clutch Actuator
SA; Shift actuator
CLR; controller
S10; Release start stage
S40; First initialization step
S50; 1st feedback control stage
S60; First talk handover step
S20; Rate of change adjustment stage
S30; Shift type judgment stage
S70; Second initialization step
S80; Second feedback control stage
S90; Second talk handover step
S100; Third feedback control stage
S110; Third talk handover step

Claims (9)

When the power-on downshift is initiated, a release start step in which the controller initiates release of the release-side clutch to induce the engine speed to rise above the release-side clutch speed;
A first initialization step in which the controller sets the release-side clutch torque calculated using the release-side clutch torque model as a feedforward torque, and converges the release-side clutch torque to the feedforward torque for a predetermined first reference time; ;
When the first reference time elapses, a first feedback control step in which the controller calculates a feedback torque according to the clutch slip change rate and controls the release-side clutch torque as the sum of the feedforward torque and the feedback torque;
During the first feedback control step, when the controller determines that the torque phase is ready, the release side clutch is released for a predetermined second reference time and the engagement side clutch torque is increased corresponding to the engine torque. First talk handover step;
A shift control method for a DCT vehicle, comprising: In claim 1,
After the release start step and before the first initialization step, if the controller determines that the difference between the engine speed and the release side clutch speed is greater than or equal to a predetermined first reference value, the controller adjusts the slope for reducing the release side clutch torque. Configured to perform further rate-of-change adjustment steps
A shift control method for a DCT vehicle characterized by . In claim 1,
Before the first initialization step, the controller is configured to further perform a shift type determination step to determine whether it is biaxial shifting or coaxial shifting, and in the case of biaxial shifting, perform the first initialization step.
A shift control method for a DCT vehicle characterized by . In claim 3,
If the controller performs the shift type determination step and is in a coaxial shift situation,
A second initialization step in which the controller sets the release-side clutch torque calculated using the release-side clutch torque model as a feedforward torque, and converges the release-side clutch torque to the feedforward torque for a predetermined third reference time; ;
When the third reference time elapses, a second feedback control step in which the controller calculates a feedback torque according to the clutch slip change rate and controls the release-side clutch torque as the sum of the feedforward torque and the feedback torque;
During the second feedback control step, when the controller determines that the torque phase is ready, 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 has elapsed, the controller switches the roles of the engaging side clutch and the disengaging side clutch, so that the clutch that has so far acted as the engaging side clutch becomes the disengaging side clutch, and the torque of this disengaging side clutch is changed. A third feedback control step of controlling by the sum of the feed forward torque calculated from the release side clutch torque model and the feedback torque according to the clutch slip change rate;
During the third feedback control step, when the controller determines that the torque phase is ready, the release side clutch is released for a predetermined fifth reference time and the engagement side clutch torque is increased corresponding to the engine torque. Third talk handover step;
A shift control method for a DCT vehicle, characterized in that it is configured to further perform. In claim 1,
The release side clutch torque model is the following formula,

; Release side clutch torque
; engine torque
; Engine moment of inertia
Slip; Ne-Ni
Ne; engine speed
Ni; Combined clutch rotation speed
; Torque due to drivetrain inertia
A shift control method for a DCT vehicle, characterized in that it is configured as follows. In claim 1,
While performing the first feedback control step, the controller completes engagement of the target stage gear, the shift progress rate is greater than or equal to a predetermined second reference value, or the difference between the engine speed and the engagement side clutch speed is greater than the third reference value, and the engagement side clutch When preparations for conclusion are completed, it is configured to determine that preparations for execution of the torque phase are complete.
A shift control method for a DCT vehicle characterized by . In claim 4,
While performing the second feedback control step, the controller completes engagement of the target gear, 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 the fifth reference value, and the engagement side clutch When preparations for conclusion are completed, it is configured to determine that preparations for execution of the torque phase are complete.
A shift control method for a DCT vehicle characterized by . In claim 4,
While performing the third feedback control step, the controller completes engagement of the target gear, the shift progress rate is greater than or equal to a predetermined sixth reference value, or the difference between the engine speed and the engagement side clutch speed is greater than the seventh reference value, and the engagement side clutch When preparations for conclusion are completed, it is configured to determine that preparations for execution of the torque phase are complete.
A shift control method for a DCT vehicle characterized by . In claim 1,
The feedback torque is calculated 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 clutch speed;
The release-side clutch torque model that calculates the feedforward torque is configured to use the target clutch slip change rate.
A shift control method for a DCT vehicle characterized by .

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