KR101988131B1 - Method of controlling shift for dct vehicle - Google Patents

Abstract

A method of controlling a shift of a DCT vehicle according to the present invention includes the steps of: detecting whether the control unit starts an inertia phase period during upshift of the vehicle; Determining whether the gear releasable condition is satisfied based on at least one of an inclination of a road surface, a vehicle speed, a transmission oil temperature, or an accelerator pedal depression amount when the inertia phase section starts as a result of the sensing step; And releasing the engagement of the N-stage gear, which is the release gear, when the controller determines that the gear releasable condition is satisfied as a result of the determining step.

Description

METHOD OF CONTROLLING SHIFT FOR DCT VEHICLE [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shift control method for a DCT vehicle that minimizes a transmission drag due to unnecessary gear engagement by releasing a release gear conditionally in a state in which a torque phase is completed during an upshift.

DCT (Dual Clutch Transmission) has two input shafts connected to the two clutches, and the arrangement of the speed change gears provided on these two input shafts is divided into an odd numbered side and an even numbered side so that one of two input shafts is shifted And the other one is provided to implement the even-numbered speed change stage.

When the DCT is sequentially shifted from a certain gear position to the next gear position, the clutch connected to the input shaft is released as long as the present gear position gear is engaged, and the other input shaft So that the shifting is performed while the connected clutch is engaged.

Thus, there is an advantage that shifting can be performed while preventing the torque transmitted to the drive wheels from being completely disconnected during shifting.

Generally, the upshift in the DCT vehicle is performed after the torque phase period in which the release side clutch torque is switched to the engagement side clutch torque, in the Inertia Phase period in which the engine speed is synchronized with the engagement side input shaft speed It is done while passing.

At this time, the release side gear is generally controlled to be released after the inertia phase period is completed.

It should be understood that the foregoing description of the background art is merely for the purpose of promoting an understanding of the background of the present invention and is not to be construed as an admission that the prior art is known to those skilled in the art.

KR 10-1996-0037452 A

SUMMARY OF THE INVENTION The present invention has been proposed in order to solve such a problem, and it is an object of the present invention to minimize drag of a transmission due to unnecessary gear engagement by releasing a release gear conditionally when an inertia phase is started in an upshift situation And to provide a shift control method of a DCT vehicle that can be used for a vehicle.

According to another aspect of the present invention, there is provided a shift control method for a DCT vehicle, the method including: sensing whether an inerter phase period starts during an upshift of the vehicle; Determining whether the gear releasable condition is satisfied based on at least one of an inclination of a road surface, a vehicle speed, a transmission oil temperature, or an accelerator pedal depression amount when the inertia phase section starts as a result of the sensing step; And releasing the engagement of the N-stage gear, which is the release gear, when the controller determines that the gear releasable condition is satisfied as a result of the determining step.

In the determining step, when the inclination is included in the set gradient area, the vehicle speed is equal to or higher than the set vehicle speed, the transmission oil temperature is equal to or higher than the set temperature, and the accelerator pedal depression amount is included in the set opening area, It is determined that the condition is satisfied.

The control unit may determine that the gear releasable condition is satisfied when the vehicle speed is equal to or greater than a value obtained by adding an offset vehicle speed to a downshift gearshift pattern at the lower end of the vehicle speed.

If the result of the determination step indicates that the gear releasable condition is unsatisfactory, the control unit may maintain the engagement of the Nth gear as the release gear.

Determining whether the gear pre-sum condition is satisfied based on at least one of a target vehicle speed, a current vehicle speed, or an engine angular acceleration, which is a vehicle speed required when the control unit shifts up the (N + 2) th stage after the releasing step; And if the result of the checking step indicates that the gear set sum condition is satisfied, the controller may preliminarily arrange the (N + 2) -th gear as the pre-combination gear.

The control unit may confirm that the gear set sum condition is satisfied when the calculated value obtained by dividing the value obtained by subtracting the current vehicle speed from the target vehicle speed by the engine angular acceleration is equal to or smaller than a set value .

According to the shift control method of the DCT vehicle having the above-described structure, when the torque phase section is completed in the upshift state and the inertia phase is started, the release side gear is released according to the conditions, (Drag) can be minimized.

Further, it is predicted that upshifting occurs one more time in succession, and the gearshift summing is performed quickly, so that the shift response of the vehicle can be improved.

1 is a flowchart showing a shift control method of a DCT vehicle according to an embodiment of the present invention;
2 is a simplified illustration of a DCT vehicle according to one embodiment of the present invention,
3 is a graph showing a vehicle state according to a shift control method of the DCT vehicle according to the present invention.

Hereinafter, a shift control method of a DCT vehicle according to a preferred embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a flowchart showing a shift control method of a DCT vehicle according to an embodiment of the present invention, and FIG. 2 is a view illustrating a DCT vehicle according to an embodiment of the present invention.

Referring to FIGS. 1 and 2, a method for controlling a shift of a DCT vehicle according to the present invention includes the steps of (S10) detecting whether the control unit 115 starts the inertia phase period during upshift transmission of the vehicle; As a result of the sensing step S10, when the inertia phase interval starts, the controller 115 determines whether the gear releasable condition is satisfied based on at least one of the inclination of the road surface, the vehicle speed, the transmission oil temperature, (S20); (S30), when the control unit 115 determines that the gear releasable condition is satisfied as a result of the determining step S20, canceling the engagement of the n-th gear as the release gear.

That is, when upshift transmission is performed from the n-th stage to the (n + 1) -th stage, the releasing-side clutch torque is released, and a torque phase section in which the coupling-side clutch torque rises occurs. Thereafter, the engine speed gradually decreases and an inertia phase section synchronized with the engagement-side rotational speed is generated.

In this inertia phase section, since the release side clutch torque is maintained in the released state, the release side gear (n-stage gear) does not need to be held in the engagement state separately.

Therefore, the control unit 115 of the present invention first confirms that the inertia phase period starts (S10), and if the condition for releasing the gear is satisfied (S20), the engagement of the n-stage gear as the release side gear is quickly released , It is possible to prevent a transmission drag force from being generated due to an unnecessary gear engagement and to prevent a shift jam due to gear engagement from occurring.

Further, since the releasing-side gear is released in the inertia-phase section for the main purpose, the speed of the releasing-side input shaft can be reduced at an earlier point in time, and the shifting can be performed quickly in the upshift situation that occurs thereafter. A detailed description will be given later.

In particular, in the determining step S20 of the present invention, the controller 115 determines that the inclination is included in the set gradient area, the vehicle speed is less than the set vehicle speed, the transmission oil temperature is equal to or higher than the set temperature, When it is included in the opening region, it can be determined that the gear releasable condition is satisfied.

The control unit 115 senses the inclination of the road surface using the inclination sensor, senses the vehicle speed through the vehicle speed sensor, senses the temperature of the transmission oil through the oil temperature sensor, accelerates the accelerator pedal through the APS Sensing the amount of input.

The gear releasable condition means a condition that is presented to be satisfied only when another upshift is expected to occur after the current upshift.

That is, the control unit 115 is set to release the releasing side gear (n-th gear) in the inertia phase only in a situation where another upshift is expected after the current upshift.

Specifically, in order to satisfy the gear releasable condition, the inclination of the road surface must be included in the set gradient area. Here, it is preferable that the set gradient area is set to an inclination determined to be a downhill length with a minimum value, and the maximum value is set to an inclination determined to be an uphill of a high gradient. That is, it is judged that another upshift can be predicted only after the inclination of the road surface is a flat or low grade inclination.

If the slope of the road surface is sharp, a downshift may occur. Even if the release side gear (n-stage gear) is released, the release side gear is required to be engaged again. .

Further, the control unit 115 releases the release side gear (n-stage gear) only when the vehicle speed is equal to or higher than the set vehicle speed. In other words, if the vehicle is traveling in a lower range, noise is generated during gear engagement / disengagement to give a feeling of discomfort to the driver, and there is a high possibility that a downshift will occur in the future.

Then, the control unit 115 releases the releasing side gear (n-stage gear) only when the transmission oil temperature is equal to or higher than the set temperature. Even in vehicles with DCT (Dual Clutch Transmission), transmission oil is required for gearing, lubrication and cooling of the transmission. At this time, if the temperature of the transmission oil is too low, the viscosity of the oil becomes high, and it takes a long time to perform gear shifting, which makes it difficult to provide a quick shift response and cause a severe gear engagement noise. Therefore, it can be compared with the set temperature to determine whether the transmission oil temperature is extremely low.

In addition, the control unit 115 releases the releasing side gear (n-th gear) only when the amount of the accelerator pedal depression is included in the set opening region.

The minimum value in the set opening range is set to determine whether the amount of the accelerator pedal input is excessively small, and the maximum value is set as a value for determining whether there is a high possibility that a downshift will occur later. That is, when the amount of the accelerator pedal is too small to be less than the set opening degree, the engagement state of the releasing side gear is maintained in the low opening state, so that the shifting engagement occurs due to releasing of the releasing side gear in the quiet state, .

Further, when the amount of the accelerator pedal depression is excessively larger than the set opening degree region, it is determined that there is a high possibility that downshift shifting will occur after that, and the engagement of the release side gear is maintained. Therefore, it is possible to minimize the occurrence of noise due to unnecessary gear engagement or disengagement.

That is, when the inclination of the road surface is included in the set gradient area, the vehicle speed is equal to or higher than the set vehicle speed, the transmission oil temperature is equal to or higher than the set temperature, and the accelerator pedal depression amount is included in the set opening range, It is determined that the noise is minimized and the releasing gear is released.

Alternatively, in the determining step S20, the controller 115 may determine that the gear releasable condition is satisfied when the vehicle speed is equal to or greater than the value obtained by adding the offset vehicle speed to the downshift shift pattern at the lower end.

That is, when the APS sensing value and the vehicle speed value of the current vehicle are shifted away from the downshift shift pattern in the n-th stage in the state where the shift from the n-th stage to the (n + 1) th stage is performed, It is determined that the gear releasable condition is satisfied to release the n-th gear as the gear. Therefore, the release side input shaft rotational speed can be rapidly reduced, and the upshift can be promptly performed later.

The offset vehicle speed means a value set in order to confirm that the current vehicle speed is formed at a position spaced apart from the lower-stage downshift shift pattern within a speed change pattern by a predetermined vehicle speed difference, and an appropriate value can be calculated through a plurality of experiments.

In addition, the present invention further includes a step (S40) of, when it is determined that the gear releasable condition is unsatisfactory as a result of the determining step (S20), the control unit 115 maintains the engagement of the nth gear as the release gear can do.

That is, when the gear releasable conditions are unsatisfactory, the control unit 115 maintains the disengagement state of the disengagement side gear to prevent noise from being released by gear release or engagement, and unnecessarily target It prevents the gear from being released.

If the gear trap sum condition is satisfied based on at least one of the target vehicle speed, the current vehicle speed or the angular acceleration of the engine, which is the vehicle speed required when the control unit 115 shifts up by n + 2 steps after the releasing step S30 (S50); And the step S60 of accumulating the (n + 2) -th gear as the pre-combination gear when the control unit 115 confirms that the gear set summing condition is satisfied as a result of the checking step (S50) .

That is, after releasing the n-th gear as the release side gear, the controller 115 predicts the (n + 2) -th upshift and pre-arranges the (n + 2) -th gear so that the vehicle can be quickly shifted.

Specifically, in the checking step (S50), when the calculated value obtained by dividing the value obtained by subtracting the current vehicle speed from the target vehicle speed by the engine angular acceleration is equal to or smaller than the set value, .

Here, it can be determined that as the value obtained by subtracting the current vehicle speed from the target vehicle speed, which is the vehicle speed required at the (n + 2) -th stage upshift, becomes smaller, the possibility that the current vehicle speed is adjacent to the target vehicle speed and the upshift increases.

Further, it can be judged that as the angular acceleration of the engine becomes larger, the possibility that the engine speed quickly approaches the engagement-side input shaft rotation speed and the upshift occurs is increased.

Therefore, the control unit 115 predicts that the second upshift will be performed only when the calculated value obtained by dividing the value obtained by subtracting the current vehicle speed from the target vehicle speed by the engine angular acceleration is equal to or smaller than the set value, So that rapid shifting can be achieved.

3 is a graph showing a vehicle state according to a shift control method of the DCT vehicle according to the present invention.

When the n-stage n + an upshift starting with the first stage, the fastening from the release-side clutch torque and the engage-side clutch torque is the torque phase interval occurs which is inverted from each other, and the engine speed (Ne) a release-side input shaft speed (Ni ₁₎ The inertia phase interval synchronized with the side input shaft speed Ni ₂ is performed. At this time, when the gear releasing condition is satisfied and the engagement of the n-th gear is released, the release side input shaft speed Ni ₁ is reduced, and the upshift that occurs later can be quickly prepared.

According to the shift control method of the DCT vehicle having the above-described structure, when the torque phase section is completed in the upshift state and the inertia phase is started, the release side gear is released according to the conditions, (Drag) can be minimized.

Further, it is predicted that upshifting occurs one more time in succession, and the gearshift summing is performed quickly, so that the shift response of the vehicle can be improved.

While the present invention has been particularly shown and described with reference to specific embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the following claims It will be apparent to those of ordinary skill in the art.

S10: Detection phase
S20: Judgment step
S30: Release step
S40: Maintenance phase
S50: Identification step
S60: Deposit step
100: engine
105: ECU
110: Transmission
115:

Claims (6)

Detecting whether the control unit starts the inertia phase section during upshift of the vehicle;
Determining whether the gear releasable condition is satisfied based on at least one of an inclination of a road surface, a vehicle speed, a transmission oil temperature, or an accelerator pedal depression amount when the inertia phase section starts as a result of the sensing step; And
And releasing the engagement of the n-th gear, which is the release gear, when the controller determines that the gear releasable condition is satisfied as a result of the determining step,
Wherein the control unit determines that the gear releasable condition is satisfied when the vehicle speed is equal to or greater than a value obtained by adding an offset vehicle speed to a downshift shift pattern to a lower stage of the vehicle speed. The method according to claim 1,
In the determining step, when the inclination is included in the set gradient area, the vehicle speed is equal to or higher than the set vehicle speed, the transmission oil temperature is equal to or higher than the set temperature, and the accelerator pedal depression amount is included in the set opening area, And determines that the condition is satisfied. delete The method according to claim 1,
Further comprising the step of, when it is determined that the gear releasable condition is unsatisfactory as a result of the determining step, maintaining the engagement of the n-th gear, which is the release gear, by the control unit. The method according to claim 1,
Determining whether the gear set sum condition is satisfied based on at least one of a target vehicle speed, a current vehicle speed, or an engine angular acceleration, which is a vehicle speed required when the n + 2-th upshift is performed after the releasing step; And
Further comprising the step of preliminarily arranging the (n + 2) -th gear as the pre-combination gear, when it is confirmed that the gear pre-sum condition is satisfied as a result of the checking step. The method of claim 5,
Wherein the control unit confirms that the gear set sum condition is satisfied when the calculated value obtained by dividing the value obtained by subtracting the current vehicle speed from the target vehicle speed by the engine angular acceleration is equal to or smaller than a set value, .

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