KR20200124349A - Control method for shift of hybrid electric vehicle - Google Patents

Abstract

The present invention relates to a control method during shifting of a hybrid vehicle. The main object is to provide a shift control method during shifting, which can properly maintain the feeling of deceleration of a vehicle when a gear of a transmission is changed from a driving gear (D gear) to a neutral gear (N gear) by operating a shift lever during deceleration of the hybrid vehicle. To this end, disclosed is the control method during shifting of a hybrid vehicle, wherein brake cooperative control for generating hydraulic braking force based on the amount of regenerative braking is performed before a clutch slip, and brake cooperative control for generating hydraulic braking force based on clutch transmission torque is performed after the slip.

Description

Control method for shift of hybrid electric vehicle {Control method for shift of hybrid electric vehicle}

The present invention relates to a control method for shifting a hybrid vehicle, and more particularly, to a control method capable of maintaining a vehicle deceleration feeling when shifting to a transmission neutral (N-stage) during deceleration of a hybrid vehicle.

A hybrid vehicle refers to a vehicle using two or more different types of driving sources, and generally refers to a vehicle driven by an internal combustion engine (ICE) and an electric motor.

Hybrid vehicles are capable of maximizing vehicle fuel economy as well as outputting optimal torque depending on how the engine and motor are harmoniously operated during the driving process.

A hybrid vehicle can constitute a drivetrain in various structures, and a transmission mounted electric device (TMED) hybrid system in which an engine and a motor are connected through an engine clutch and a transmission is connected to the motor output side is known.

In the TMED hybrid system, the transmission is mounted on the output side of the vehicle driving motor, and the motor output shaft is connected to the transmission input shaft, so the transmission input shaft rotational speed (that is, the transmission input speed) is the same as the motor speed.

The transmission shifts the rotational power of the motor or the combined rotational power of the engine and the motor and transmits it to the driving wheel through the drive shaft, and as a transmission of a hybrid vehicle, an automatic transmission (AT) or a dual clutch transmission (Dual Clutch Transmission) DCT) can be used.

The hybrid vehicle can be driven in an electric vehicle (EV) mode, which is a pure electric vehicle mode that runs using only the power of a motor, or in a hybrid electric vehicle (HEV) mode, which runs using a combination of engine power and motor power.

In addition, during braking of the vehicle or coasting due to inertia, a regenerative mode is performed in which kinetic energy of the vehicle is recovered through a motor to charge the battery.

In the regenerative mode, the motor receives the kinetic energy of the vehicle through the vehicle wheel, and the motor operates as a generator to charge the battery through the inverter.

On the other hand, when regenerative braking is executed during vehicle deceleration (during braking) while the transmission is mounted in the TMED hybrid vehicle that physically releases the gear in N-speed (neutral), the driver manipulates the shift lever to change the transmission to N-speed. In this case, it is difficult to maintain the feeling of deceleration of the vehicle, and shock is likely to occur.

In general, for safety reasons, the transmission of power from the transmission is mechanically and electronically cut off at the N-speed. At this time, if the power transmission is mechanically cut off, it is difficult to control the vehicle.

In particular, when the clutch in the transmission is disengaged, the power is cut off at the rear end of the motor, so the motor speed decreases rapidly due to the negative motor torque, and the experience during braking of an existing internal combustion engine vehicle due to a sudden change in the clutch transmission torque. It can be a dissatisfaction factor due to the occurrence of an unsuccessful shock.

In addition, the brake control unit (BCU) controls the generation of hydraulic braking torque except for the regenerative braking amount in order to satisfy the required braking torque.In the case of N-stage in the transmission, the clutch transmission torque decreases rapidly, The hybrid control unit (HCU) relatively slowly raises the torque command (motor torque command) to the vehicle drive source, and the brake controller applies the brake hydraulic pressure based on this, and the vehicle bounces without maintaining a certain deceleration. Exiting may occur.

In addition, even if it is electronically controlled, it is difficult to maintain a constant vehicle acceleration by raising the input torque command value irrespective of the clutch control like the conventional physical gear release system.

That is, in a situation in which slip occurs due to the release of the clutch, even though the output torque is irrelevant to the input torque, the brake control only considers the regenerative braking torque, making it impossible to secure a constant deceleration.

In addition, when the control is terminated in this way, it is difficult to predict the change in the motor speed, and thus it is disadvantageous in connection with the next control.

1 is a diagram illustrating a prior art, and illustrates a control state when a driver operates a shift lever in an N-level during vehicle deceleration.

1 is a diagram showing two diagrams on the upper side and the lower side, respectively, in the upper diagram, the vertical axis represents speed (ω), the horizontal axis represents time, and in the lower diagram, the vertical axis represents torque (TQ), and the horizontal axis represents time. Represents.

In the lower diagram, based on the horizontal axis (TQ = 0Nm), the lower region represents the negative (-) torque region and the upper region represents the positive (+) torque region.

In addition, in the diagram of FIG. 1, N _Mj denotes the synchronous speed at the previous driving stage (D stage) of the N stage, N _M denotes the transmission input shaft rotation speed (transmission input speed), and in the TMED hybrid system, the transmission input shaft rotation speed ( N _M ) is the same as the speed of the motor that drives the vehicle.

In the following description, the clutch means the clutch in the transmission, and more specifically, the clutch of the transmission that was coupled to transmit power from the driving stage before the shift when shifting from the driving stage (D stage) to the neutral stage (N stage), In other words, it refers to a release clutch, which is a clutch that must be released when shifting from the driving stage to the neutral stage.

In the diagram of FIG. 1, T _R represents the transmission torque of the transmission clutch (release clutch), and TC _R represents the clutch torque of the transmission clutch (release clutch).

T _o represents the transmission output torque (i.e., the transmission output shaft torque), T _i represents the transmission input torque (i.e., the transmission input shaft torque), and in the TEMD hybrid system, the transmission input torque is the torque of the vehicle drive source connected to the transmission input side.

In addition, in FIG. 1, T _T represents the total braking torque based on the transmission output shaft, and T _B represents the hydraulic braking torque.

Clutch torque (TC _R ) may mean a torque command value for controlling the clutch in a transmission, and transmission torque (T _R ) is a torque value transmitted by the clutch when the clutch is controlled according to the torque command value. It could mean something.

That is, if the clutch torque TC _R is a command value related to the torque output from the controller for clutch control, the transmission torque T _R can be said to be a torque in the clutch that is a control result according to the command value.

Referring to FIG. 1, when the shift stage is changed from D to N by the driver's operation of the shift lever while regenerative braking is being performed during braking and deceleration, the transmission input shaft rotational speed (transmission input speed) (N _M ) You can see the state of sudden descent.

In addition, when the driver in the vehicle changes the speed change from D to N by operating the shift lever, the release clutch is released so that the power is cut off (the clutch is released), so regenerative braking is not possible. Increase the hydraulic braking torque (T _B ) to satisfy the required braking torque.

As described above, releasing the release clutch to be in a power-disconnected state, as shown in FIG. 1, outputs the clutch torque (TC _R ) of the release clutch as a command value corresponding to 0 Nm, and is a result of clutch control according to the command value. It means that the transmission torque (T _A ) of the release clutch is reduced (increased on the drawing) to a torque of 0 Nm.

In addition, since the power is cut off when the shifting stage of the transmission is changed from D to N, as shown in Fig. 1, transmission input torque (transmission input shaft torque) (T _i ) and transmission output torque (transmission output shaft torque) (T _o ) will decrease based on the absolute value in the negative torque area, resulting in a torque of 0Nm.

In addition, referring to FIG. 1, the hydraulic braking torque (T _B ) is shown as a negative (-) torque value, and at this time, it is increased based on the absolute value in the negative torque region, that is, as a negative (-) value. On the drawing, you can see a state of sharply descending (decreasing).

Since the regenerative braking torque becomes a torque of 0 Nm when the shift to the N-speed is completed, the total braking torque required during deceleration is satisfied only with the hydraulic braking torque T _B.

However, according to the conventional shift control method as described above, as described above, a hybrid equipped with a transmission that electronically releases the gear when the shift lever is moved from the D gear (driving end) to the N gear (neutral gear). In a vehicle, since cooperative control with a brake controller considering only rapid release of the motor regenerative braking torque is performed, there is a problem in that it is impossible to maintain a feeling of deceleration of the vehicle.

In addition, it is difficult to predict the change in the motor speed after the control, and there is a disadvantage in the next control.

Accordingly, the present invention was created to solve the above problems, and the driver operates the shift lever during deceleration of the hybrid vehicle so that the gear stage of the transmission is changed from the driving stage (D stage) to the neutral stage (N stage). It is an object of the present invention to provide a control method during shifting that can properly maintain a feeling of deceleration of a vehicle.

In order to achieve the above object, according to an embodiment of the present invention, when the controller receives a shift command from the driving end to the neutral end of the transmission during regenerative braking during vehicle deceleration, the transmission torque of the release clutch is reduced in the clutch release direction. A first step of controlling the torque of the vehicle driving source connected to the transmission input side such that the transmission input torque decreases based on an absolute value in a negative torque region; When the controller determines that the transmission input shaft rotational speed differs from the set synchronous speed of the driving stage by a certain level or more, the release clutch is released by reducing the transmission torque of the release clutch, and the transmission input speed is set to a target speed. A second step of performing vehicle drive source speed control for a neutral shift to follow; And a third step of terminating the vehicle drive source speed control for the neutral shift when the controller determines that the release clutch has reached the release state, wherein in the first step, the controller is It provides a control method during shifting of a hybrid vehicle, characterized in that the hydraulic braking is controlled according to the hydraulic braking torque determined from the braking torque and the target regenerative braking execution amount.

In addition, in the second step, the controller controls the hydraulic braking according to the hydraulic braking torque determined from the total braking torque during vehicle deceleration and the torque of the release clutch.

In addition, in the second step, the controller has the transmission input speed as the target speed,'synchronous speed-(ΔN _M ) _B '(where (ΔN _M ) _B is a positive (+) value as a preset margin) It characterized in that it controls the speed of the vehicle drive source to follow.

Accordingly, according to the control method during shifting of the hybrid vehicle according to the present invention, it is possible to secure a uniform vehicle deceleration feeling without impact during the N-speed shift during deceleration (during braking).

That is, before the clutch slip, brake cooperative control to generate hydraulic braking force based on the amount of regenerative braking is performed, and after slipping, brake cooperative control to generate hydraulic braking force based on the clutch transfer torque is performed. It becomes possible to secure a uniform deceleration feeling without fluctuations in shock and vehicle deceleration due to sudden change in

In addition, it is possible to secure responsiveness even after the transmission input shaft rotational speed control performed during the N-speed shift during deceleration (during braking).In order to secure responsiveness after shifting, the vehicle drive source speed is controlled to be lower than the synchronous speed in controlling the transmission input shaft rotational speed. By performing the operation, it is possible to maintain the vehicle deceleration rate, but there is an advantage in that the vehicle driving source speed can be converged to a desired speed in advance to quickly respond to subsequent control.

1 is a diagram illustrating a control state during an N-speed shift according to the prior art.
2 is a system configuration diagram of a hybrid vehicle to which a control method for shifting according to the present invention can be applied.
3 is a block diagram showing main functions performed by each controller in a plurality of vehicles in the present invention.
4 is a flowchart illustrating a control process when changing an N-stage of a hybrid vehicle according to an embodiment of the present invention.
5 is a diagram illustrating a control state diagram of a hybrid vehicle according to an embodiment of the present invention when the N-stage is changed.
6 is an enlarged view of a portion indicated by a circle in FIG. 5.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those of ordinary skill in the art may easily implement the present invention. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms.

When a part of the specification "includes" a certain component, it means that other components may be further included rather than excluding other components unless otherwise stated.

The present invention relates to a control method during shifting of a hybrid vehicle, in which a driver operates a shift lever during deceleration (during braking) of a hybrid vehicle so that a gear stage (shift stage) of a transmission is shifted from the driving stage (D stage) to the neutral stage (N However, it is intended to provide a control method during shifting that can properly maintain the feeling of deceleration of the vehicle when it is changed to).

To this end, an improved control method for maintaining a uniform vehicle deceleration feeling by changing the brake cooperative control according to a clutch state of a transmission when the neutral stage is changed during deceleration and controlling the motor speed to a desired speed is disclosed.

The shift control method of the present invention can be applied to a hybrid vehicle in which regenerative braking and hydraulic braking are performed. As an example, it can be applied to a TMED hybrid vehicle, and an automatic transmission (AT) or a dual clutch transmission (DCT) is used. It can be applied to equipped vehicles.

In addition, the pre-stop downshift control process of the present invention includes known in-vehicle controllers, that is, a hybrid controller (HCU), a transmission control unit (TCU), a motor controller (Motor Control Unit, MCU), A plurality of controllers such as an engine controller (ECU) and a brake controller (BCU) may be cooperatively controlled and performed, or may be performed by one controller having an integrated function of these controllers.

Hereinafter, a method for controlling a downshift before stopping of a hybrid vehicle according to an embodiment of the present invention will be described in detail with reference to FIGS. 2 to 6.

2 is a system configuration diagram of a hybrid vehicle to which the shift control method of the present invention can be applied, and shows the system configuration of a TMED hybrid vehicle.

As shown, in the hybrid vehicle, the engine 90 and the motor 110, which are driving sources for vehicle driving, the engine clutch 100 interposed between the engine 90 and the motor 110, and the output side of the motor 110 It includes a transmission 120 connected to.

In addition, the hybrid vehicle is equipped with a hybrid controller (HCU) 20, which is a host controller that controls the overall operation of the vehicle, and various controllers that control various devices of the vehicle are provided.

For example, an engine controller (ECU) 30 that controls the operation of the engine 90, a transmission controller (TCU) 40 that controls the operation of the transmission 120, and the state information of the battery 70 are collected and A battery controller (BMS) 50 that uses, provides, and performs control for battery management, a motor controller 60 for driving and controlling the motor 110, and a brake controller (BCU) for performing braking control of the vehicle ( 80) and the like are provided.

Here, the brake controller 80 may be an electronic control unit of an active hydraulic booster (AHB) known as a regenerative braking device of an eco-friendly vehicle that performs regenerative braking control and hydraulic braking control.

In addition, the battery 70 is connected to the motor 110 to be charged and discharged through an inverter (not shown) of the motor controller 60.

In FIG. 2, reference numeral 130 denotes a hydraulic circuit for generating brake hydraulic pressure, and reference numeral 131 denotes a wheel brake installed on the vehicle wheel 9 to generate hydraulic braking force (ie, friction braking force).

The hybrid vehicle is provided with a hydraulic braking device (friction braking device), and the hydraulic braking device is installed in the hydraulic circuit 130 for generating brake hydraulic pressure, and the brake hydraulic pressure generated by the hydraulic circuit 10 by being installed on the vehicle wheel 9. It includes a wheel brake 131 that generates a braking force (friction braking force) thereby.

The brake controller 80 controls the operation of the hydraulic brake system, and controls the operation of hydraulic actuators and valves not shown in the hydraulic circuit 130 to control the brake hydraulic pressure applied to the wheel cylinder of the wheel brake 131 do.

The hybrid controller 20 and each controller perform cooperative control on the in-vehicle device while exchanging information with each other through CAN communication, and the upper controller transmits control commands to the lower controller while collecting various information from the lower controllers. .

In FIG. 2, the driving information detection unit indicated by reference numeral 10 is for detecting vehicle driving information, and the vehicle driving information may include driving input information and vehicle state information.

The driving input information may include a driver's brake pedal operation state, accelerator pedal operation state, and shift lever operation state, and the vehicle state information may include vehicle speed and motor speed.

The driving information detection unit 10 includes an accelerator pedal sensor (APS) that outputs a signal according to the driver's accelerator pedal operation, and a brake pedal sensor (BPS) that outputs a signal according to the driver's brake pedal operation. , A shift detection unit for detecting the position of the shift lever, a vehicle speed detection unit for detecting the vehicle speed, and a motor speed detection unit for detecting the motor speed, and these include the hybrid controller 20 and the shift controller 40 May be connected to enable input of a detection value to the field.

3 is a block diagram showing the main functions performed by the in-vehicle controllers in the present invention. When the controllers involved in the control method of the present invention are further described, the shift controller 40 is in the driving information detection unit 10 From the vehicle driving information detected by the driver, it is determined whether the gear stage of the transmission 120 has been changed from the driving stage D to the neutral stage N.

That is, the shift controller 40 determines that the gear stage of the transmission has been operated from the D gear to the N gear by the driver from the position information of the shift lever detected by the shift detection unit of the driving information detection unit 10.

In addition, the shift controller 40 performs torque control of the release clutch for shifting from D to N when the gear stage of the transmission is operated from D to N, at this time, the control command value for the release clutch, that is, the clutch By outputting a command value corresponding to the torque TC _R , the operation of the release clutch is controlled according to the output command value, so that the clutch transmission torque T _R in the transmission can be controlled.

In addition, the shift controller 40 transmits information on the clutch transmission torque to the hybrid controller 20 for hydraulic braking cooperative control, as described later.

The hybrid controller 20 performs control for releasing the transmission input torque T _i to be a torque value of 0Nm when the N-stage operation is performed, and transmits a target regenerative braking execution amount (which is a torque value) to the brake controller 80, The brake controller 80 allows hydraulic braking control based on the target regenerative braking execution amount to be performed.

Further, the hybrid controller 20 controls the speed of the vehicle driving source to be the transmission input shaft rotation speed N _M based on the target input speed.

In the present invention, when the release clutch is released and the slip occurs during the N-speed operation, the hybrid controller 20 performs a control to release the transmission input torque T _i until the slip determination, and after the slip determination, the target input speed is based. To control the transmission input shaft rotation speed (N _M ).

Here, the vehicle driving source in the speed control may be the motor 110 alone or the engine 90 and the motor 110, and in the present invention, the motor speed is controlled or required to control the transmission input shaft rotation speed (N _M ). It is possible to control the engine speed together with the motor speed at the time.

The target input speed means a set target speed at the driving stage (D stage) before shifting to the N stage, that is, the synchronous speed N _Mj based on the transmission input shaft.

In the TMED hybrid system, the transmission input shaft rotation speed (transmission input speed) (N _M ) is the same as the speed of the vehicle drive source connected to the transmission input side, that is, the speed of the motor.

In addition, the motor controller 60 performs motor speed control and motor torque control according to the control command of the hybrid controller 20, the engine controller 30 performs engine speed control when necessary, and the brake controller 80 It controls the operation of the hydraulic braking system to generate the necessary hydraulic braking force (hydraulic braking torque) during the control process during shifting.

In the present invention, during the N-speed shift, the brake controller 80 performs hydraulic braking control for generating and controlling hydraulic braking torque based on the target regenerative braking execution amount (which is a torque value) sent from the hybrid controller 20, and Hydraulic braking control for generating and controlling hydraulic braking torque is performed based on torque information of the release clutch transmitted from the shift controller 40.

In particular, the brake controller 80 performs control to generate hydraulic braking torque based on the target regenerative braking execution amount until the slip determination, and after the slip determination, the control to generate hydraulic braking torque based on the torque value of the release clutch. Perform.

As described above, the control process according to the exemplary embodiment of the present invention may be performed by cooperative control between a plurality of controllers. Hereinafter, a plurality of controllers are classified according to functions, and the plurality of divided controllers cooperatively control. It will be described as performing a control process according to an embodiment of the present invention.

However, a plurality of controllers may be collectively referred to as a single controller and described. Furthermore, one controller actually integrated may perform a control process according to an embodiment of the present invention.

4 is a flow chart showing a control process when changing the N-stage of a hybrid vehicle according to an embodiment of the present invention, and FIG. 5 is a diagram illustrating a diagram of a control state when changing the N-stage of a hybrid vehicle according to an embodiment of the present invention It shows the motor speed and torque status during the shift from D to N.

In addition, FIG. 6 is an enlarged view of a portion indicated by a circle in FIG. 5, and is an enlarged view of a part of a speed control state for maintaining a feeling of deceleration when a hybrid vehicle is changed from D to N.

First, briefly describing the drawings, FIG. 4 shows a main process of cooperative control performed by the hybrid controller (HCU) 20, the shift controller (TCU) 40, and the brake controller (BCU) 80.

In addition, FIG. 5 is a view in contrast to FIG. 1 illustrating the prior art. Like FIG. 1, diagrams are shown on the upper side and the lower side respectively, showing two diagrams.

In the upper diagram of FIG. 5, the vertical axis represents speed (ω), the horizontal axis represents time, and in the lower diagram, the vertical axis represents torque (TQ), and the horizontal axis represents time.

In addition, in the lower diagram of FIG. 5, based on the horizontal axis (TQ = 0Nm), the lower region represents a negative (-) torque region, and the upper region represents a positive (+) torque region.

In the diagram of FIG. 5, N _Mj denotes the synchronous speed, N _M denotes the transmission input shaft rotation speed (transmission input speed), and the transmission input shaft rotation speed in the TMED hybrid system is the same as the motor speed.

In addition, in the diagram of Fig. 5, T _R represents the transmission torque of the clutch, and TC _R represents the clutch torque.

In the following description, the clutch refers to the clutch in the transmission 120, and more specifically, the transmission that was coupled to transmit power from the driving stage before the shift when shifting from the driving stage (D stage) to the neutral stage (N stage) It refers to the release clutch, which is a clutch that must be released when shifting from the driving end to the neutral end.

In addition, in FIG. 5, T _o represents the transmission output torque (that is, the transmission output shaft torque), T _i represents the transmission input torque (that is, the transmission input shaft torque), T _T represents the total braking torque based on the transmission output shaft, and T _B is It represents the hydraulic braking torque based on the transmission output shaft.

Clutch torque (TC _R ) may mean a torque command value for controlling the clutch in the transmission 120, and transmission torque (T _R ) is transmitted by the clutch when the clutch is controlled according to the torque command value. It may mean a torque value.

That is, if the clutch torque (TC _R ) is a command value related to the torque output from the transmission controller 40 for clutch control, the transmission torque (T _R ) can be referred to as the torque in the clutch resulting from the control result according to the command value. have.

In addition, in the present invention, the transmission output torque (T _o ) is the same as the transmission torque (T _R ) of the release clutch.

In FIG. 5, the transmission input torque T _i is a torque value controlled by the control of the controller or cooperative control of the controllers, and the transmission input torque T _i in the TMED hybrid system is the torque of the vehicle driving source connected to the transmission input side. .

In the present invention, the torque controlled according to the command value is the transmission input torque T _i , the hydraulic braking torque T _B , and the like, and the transmission torque T _R and the transmission output torque T _o are torques resulting from the control.

In addition, torque values in FIG. 5 are all torque values based on the transmission output shaft except for the transmission input torque T _i .

That is, the transmission torque T _R , the clutch torque TC _R , the hydraulic braking torque T _B , the total braking torque T _T , including the transmission output torque T _o are all of the transmission output shaft reference torques, and these torques are the transmission 120 ), it can be said to be equivalent torque converted and converted to the torque value at the output shaft of the transmission considering the gear ratio corresponding to the gear stage of ).

The transmission output shaft reference torque may be a torque that is directly obtained or estimated and calculated based on the transmission output shaft in addition to the converted equivalent torque.

In addition, the target regenerative braking execution amount to be described later may also be an execution amount (which is a torque value) based on the transmission output shaft.

Hereinafter, a step-by-step description of the pre-stop downshift control process according to an embodiment of the present invention with reference to FIGS. 4 to 6 will be described. First, the current vehicle driving by the shift controller 40 detected by the driving information detection unit 10 From the information, it is determined whether the shift lever is operated from the D gear to the N gear by the driver while regenerative braking is being performed during vehicle deceleration (during braking).

That is, as shown in FIG. 4, the shift controller 40 determines that there is an N-speed operation by receiving a shift command to the N-speed according to the driver's operation during vehicle deceleration, and this determination is made by the shift controller 40 This may be achieved by receiving a signal of a shift detector for detecting the position of the shift lever among the driving information detector 10.

In this way, when the shift controller 40 determines that there is an N-speed operation at point A of FIG. 5, it communicates with other controllers to perform a control process of the section A-B.

In FIG. 5, the A-B section is an input torque reduction section, and in the control phase of the input torque reduction section, control for releasing the release clutch in the engaged state is started by the shift controller 40.

At this time, the transmission controller 40 of the torque, that is, release the clutch in the release clutch whereby the release clutch control in accordance with the clutch torque (TC _R) command gradually decrease the value to output, and clutch torque (TC _R) command of the release clutch The transmission torque (T _R ) gradually decreases.

Although the transmission torque (T _R ) of the release clutch gradually decreases, the state of the release clutch in the AB section is still a state before clutch slip occurs.

In addition, even if the torque (T _R ) of the release clutch decreases to some extent in the AB section, the same torque as before shifting is transmitted through the transmission and the internal release clutch before clutch slip occurs, and target regenerative braking, which is a negative torque value, is executed. When the amount is increased, it is possible to maintain the transmission input torque (T _i ) level close to the 0 torque (0 Nm) level at the time when the clutch slip occurs, and also, the reduction of the vehicle through cooperative control with the brake controller 80 It is possible to adjust.

When the hybrid controller 20 receives a signal indicating that the driver has operated in the N-speed position from the shift controller 40 at the point A, it reduces the transmission input torque T _i , but cooperatively controls the target regenerative braking execution amount. The reduction amount of the transmission input torque T _i may be set so as to secure a stable response in the brake hydraulic pressure generated and controlled by the brake controller 80.

Since the transmission input torque (T _i ) in the AB section is a negative (-) torque applied by regenerative braking, reducing the transmission input torque (T _i ) as described above makes the transmission input torque (T _i ) negative (- ) In the torque region of the absolute value, and actually increases the transmission input torque from a negative (-) value to a direction closer to 0, that is, to a gradually larger value. Means that.

Further, the transmission input torque (T _i) that reduces the absolute value of the reference is the transmission input torque (T _i), the meaning, and thus before slip generation in the release clutch hybrid controller 20, the transmission input torque to release Control to release (T _i ) is performed.

In the AB section, the brake controller 80 performs control to generate and apply hydraulic braking torque (T _B ) as much as the absolute value of the transmission input torque (T _i ) as a reference decrease (increase in the drawing), where'total braking torque = It controls to generate and apply hydraulic braking torque that satisfies the relationship of'target regenerative braking execution amount + hydraulic braking torque'.

For the process of obtaining the target regenerative braking execution amount during deceleration (during braking) in the hybrid controller 20, a general engineer in the cooperative control process in which the total braking torque required during braking is satisfied by the regenerative braking torque and hydraulic braking torque Since it is a well-known technical matter, a detailed description will be omitted.

As a preferred embodiment, in the AB section, the torque of the release clutch (TC _R , T _R ) and the input torque of the transmission (T _i ) are both reduced by a constant slope based on the absolute value in the negative torque region (Fig. In the drawing), and at this time, the hydraulic braking torque T _B may be increased with a certain slope based on the absolute value in the negative (-) torque region (fall in the drawing in the diagram of FIG. 5 ).

Next, as the entry condition of the BC section, a condition in which the slip of the release clutch occurs can be set, and specifically, a condition that detects a decrease in the rotation speed of the transmission input shaft (N _M ) to determine the occurrence of the slip of the release clutch is set. Can be.

In more detail, in a TMED hybrid vehicle, since the transmission input shaft rotational speed (N _M ) becomes the speed of the motor connected to the transmission input side, the motor speed detected by the motor speed detection unit is not less than a certain level of difference from the synchronous speed (N _Mj ). If the state is decreased to indicate, it may be set to enter the BC section.

At this time, the hybrid controller 20 receives a signal from the motor speed detection unit and determines that the entry condition of the B-C section is satisfied, and then communicates with other controllers to perform a control process of the B-C section.

The BC section is a section in which brake cooperative control that generates hydraulic braking force (hydraulic braking torque) based on the transmission torque (T _R ) of the release clutch and speed control of the vehicle drive source are performed.

In the B-C section, the shift controller 40 continues to perform the control for releasing the release clutch following the A-B section, but it can be said that the release clutch slip has occurred from the point B.

In the BC section, the shift controller 40 gradually decreases and outputs the command value of the clutch torque TC _R of the release clutch, as in the AB section, thereby controlling the transmission torque T _R of the release clutch to gradually decrease.

Thus torque release clutch in the BC region in reducing the (TC _R, T _R), the transmission controller 40 is to reduce the torque of the release clutch (TC _R, T _R) at a constant slope, the slope of the brake controller In the cooperative control with (80), it is set at a level that can ensure the responsiveness of the brake hydraulic pressure.

Eventually, in the B-C section, release is completed after the release clutch slips.

Then, the shift controller 40 calculates a current estimate of the transmission torque and transmits it to the brake controller 80 for cooperative control with the brake controller 80.

The shift controller 40 knows the clutch torque (TC _R ) corresponding to the control command value for the release clutch, but calculates the current estimated transmission torque estimated amount of the actual transmission torque to the brake controller 80 for cooperative control. Send out.

The equation for calculating the transfer torque estimator is as follows.

T _{R_est} = sign(N _M -N _Mj )μ|TC _R | (One)

Here, T _{R_est} represents the estimated transmission torque, N _M represents the transmission input shaft rotational speed, and N _Mj represents the synchronous speed at the driving stage before shifting.

In addition, sign(x) is a function representing the value of +1 when x> 0, and the value of -1 when x <0. In equation (1), when N _M > N _Mj , sign(N _M -N _Mj ) represents a value of +1, and when N _M <N _Mj , sign (N _M -N _Mj ) represents a value of -1.

In addition, μ represents the clutch friction coefficient, which is a value commonly known by the shift controller 40 of a hybrid vehicle (may be an estimated value estimated by a known process), and | | Is a symbol representing an absolute value.

As shown in Equation (1) above, the estimated transmission torque (T _{R_est} ) calculated from the transmission input shaft rotation speed (N _M ) and the clutch torque (TC _R ) can be calculated, and this transmission torque estimated amount (T _{R_est} ) is the actual transmission output shaft. Therefore, in the present invention, when the transmission torque estimated amount T _{R_est} is calculated by the shift controller 40 and transmitted to the brake controller 80, the brake controller 80 is based on the estimated transmission torque T _{R_est} . To be able to control.

In the BC section, the hybrid controller 20 controls the vehicle drive source speed so that the transmission input shaft rotation speed (N _M ) follows a predetermined target speed, that is,'N _Mj- (ΔN _M ) _B ', and at this time, the vehicle drive source speed is controlled. For this purpose, the hybrid controller 20 may control the motor speed through cooperative control with the motor controller 60 and, if necessary, control the engine speed through cooperative control with the engine controller 30.

If the vehicle drive source speed (same as the motor speed), which is the transmission input shaft rotation speed (N _M ) in the BC section, is controlled higher than the synchronous speed (N _Mj ), a feeling of acceleration rather than a feeling of deceleration may be formed, so the synchronous speed (N _Mj ) are not, as a clearance positive value (set ΔN _{M) B} and, the motor speed (N _M) of _{'N Mj - (ΔN M)} B' with a margin so as to follow the value of the speed control Conduct.

If the transmission input torque (T _i ) is fixed at 0Nm or the previous value without controlling the speed of the vehicle drive source after the clutch slip occurs in the BC section, it becomes difficult to predict the change in the transmission input shaft rotation speed (transmission input speed). .

In addition, if the transmission input torque T _i is controlled to 0Nm after the clutch is finally released, free-wheeling is performed, resulting in a disadvantage in terms of responsiveness during the next control.

In general, in the N-speed, the speed is controlled until the transmission input shaft rotational speed (N _M ) reaches 0 rpm.

On the other hand, in the present invention, as shown in the diagram of FIG. 5, even if the driver operates the shift lever in the neutral stage N stage, the driving stage (D stage) is assumed to follow the synchronous speed (N _Mj ). It controls the speed of the vehicle drive source.

In particular, the transmission input shaft rotation speed (transmission input speed) decreases by controlling the transmission input shaft rotational speed (N _M ) to be close to the synchronous speed (N _Mj ) in advance without waiting for the release clutch to be completely released in the BC section. Minimize

In addition, in the BC section, the brake controller 80 applies the hydraulic braking torque in which the torque change amount of the release clutch, which is information received from the shift controller 40, is taken into account, and the torque of the release clutch is the shift controller ( The transmission torque estimator T _{R_est} transmitted from 40) may be used.

That is, after the brake controller 80 receives the estimated transmission torque T _{R_est} calculated according to Equation (1) from the shift controller 40 and determines a target hydraulic braking torque that satisfies the total braking torque from the estimated transmission torque, A target hydraulic braking force is generated by controlling the hydraulic braking device based on the determined target hydraulic braking torque value.

At this time, the relationship between the total braking torque (T _T ), the transmission torque (T _R ), and the target hydraulic braking torque (T _B ) is as shown in Equation (2) below.

T _T = T _{R_est} + T _B (2)

In the above equation (2), T _T represents the total braking torque based on the transmission output shaft, T _{R_est} represents the estimated _amount of transmission torque of the release clutch as the torque based on the transmission output shaft, and T _B is also the torque based on the transmission output shaft and the target hydraulic braking torque. Represents.

The brake controller 80 determines a target hydraulic braking torque (T _B ) that satisfies the total braking torque (T _T ) based on the estimated transmission torque (T _{R_est} ) of the release clutch as shown in Equation (2), and the determined target Hydraulic braking is controlled so that a target hydraulic braking torque is applied based on the hydraulic braking torque value.

In the present invention, the transmission torque (T _R ) of the release clutch, in particular, the transmission torque estimation amount (T _{R_est} ) is the same as the transmission output torque (transmission output shaft torque) (T _o ), and the transmission output torque ( Since the sum of T _O ) and the hydraulic braking torque T _B based on the transmission output shaft becomes the total braking torque T _T , the total braking torque can be kept constant throughout the shift.

Referring to FIG. 5, when controlling the speed of the vehicle driving source in the BC section, the transmission input torque T _i exceeds 0 Nm and is in a form corresponding to the change in the vehicle driving source speed and the transmission input shaft rotational speed (transmission input speed). It can be seen that it is controlled to be a torque value of +).

In addition, when the speed control for the vehicle drive source is terminated after point C, the transmission input torque (T _i ) is controlled to 0 Nm after completion of the N-speed shift, and the clutch torque of the release clutch (TC _R ) and the transmission torque of the release clutch (T _R ), the transmission output torque (To) also becomes 0Nm around the point C.

On the other hand, when the torque of the release clutch reaches the torque value corresponding to the released state after completing the control of the section B-C, the shifting is completed at the point C.

As the entry condition at point C, a condition in which the state of'absolute value of release clutch torque ≤ set value' is continuously maintained for a predetermined set time may be set, where the set value is a small value close to 0 Nm in advance. It is a fixed value.

The absolute value of the release clutch torque, which is a positive (+) value in the entry condition, can be the absolute value of the release clutch transmission torque, that is, the absolute value of the estimated transmission torque T _{R_est} calculated according to Equation (1). , Or the absolute value of the clutch torque (TC _R ), which is a command value for the release clutch.

The shift controller 40 makes a request to complete the shift to the hybrid controller 20 at the point C when the absolute value of the release clutch torque is less than the set value, which is a small value, and the hybrid controller 20 The speed control of the vehicle drive source is ended.

As described above, when the transmission torque (T _R ) of the release clutch is reduced and power transmission is blocked, the speed control for the N-speed shift is terminated, and the shift to the next control is performed. The transmission input shaft rotational speed (N _M ) at the rear N gear may be controlled to match the synchronous speed (N _Mj ) of the driving gear before shifting as shown in the diagram of FIG. 5.

Referring to FIG. 5, when the vehicle is decelerated (during braking), when there is an operation to the neutral stage, the N stage, when speed control is performed to follow the driving stage synchronous speed (N _Mj ) assuming the driving stage (D stage), C point formerly _{'N Mj - (ΔN M)} B' , after a while the speed control is set to the synchronous speed, completing the shift to the subsequent C point and the N-range is set to N _Mj at a synchronous speed to the speed control can see.

In addition, as shown in FIG. 5, even after the point C and after the shift to the N gear is completed, the total braking torque during deceleration of the vehicle remains at a constant value without change as before the shift, but after the point C and to the N gear. After the shift is completed, the hydraulic braking is controlled so that the total braking torque is satisfied with only the hydraulic braking torque.

In this way, according to the control method for the N-speed shift of the hybrid vehicle according to the present invention, it is possible to ensure a uniform vehicle deceleration feeling without impact during the N-speed shift during deceleration (during braking).

That is, before the clutch slip, brake cooperative control to generate hydraulic braking force based on the amount of regenerative braking is performed, and after slipping, brake cooperative control to generate hydraulic braking force based on the clutch transfer torque is performed. It becomes possible to secure a uniform deceleration feeling without fluctuations in shock and vehicle deceleration due to sudden change in

In addition, it is possible to secure responsiveness even after the transmission input shaft rotational speed control performed during the N-speed shift during deceleration (during braking).In order to secure responsiveness after shifting, the vehicle drive source speed is controlled to be lower than the synchronous speed in controlling the transmission input shaft rotational speed. By performing the operation, it is possible to maintain the vehicle deceleration rate, but there is an advantage in that the vehicle driving source speed can be converged to a desired speed in advance to quickly respond to subsequent control.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by the person skilled in the art using the basic concept of the present invention defined in the following claims It is also included in the scope of the present invention.

9: vehicle wheel 10: driving information detection unit
20: hybrid controller (HCU) 30: engine controller (ECU)
40: shift controller (TCU) 50: battery controller (BMS)
60: motor controller (MCU) 70: battery
80: brake controller (BCU) 90: engine
100: engine clutch 110: motor
120: transmission 130: hydraulic circuit
131: wheel brake

Claims (12)

When the controller receives a shift command from the transmission driving stage to the neutral stage during regenerative braking during vehicle deceleration, it starts the control to decrease the transmission torque of the release clutch in the clutch release direction, and the transmission input torque is in the negative torque range. A first step of controlling the torque of the vehicle driving source connected to the transmission input side so as to decrease based on an absolute value;
When the controller determines the occurrence of slip of the release clutch, the release clutch is released by continuously reducing the transmission torque of the release clutch, and the vehicle drive source speed control for shifting to the neutral stage so that the transmission input speed follows a predetermined target speed. A second step of performing; And
A third step of terminating the vehicle drive source speed control for shifting to the neutral stage, when the controller determines that the release clutch has reached the release state,
In the first step, the controller controls the hydraulic braking according to the hydraulic braking torque determined from the total braking torque during vehicle deceleration and the target regenerative braking execution amount.
The method according to claim 1,
In the first step, the controller decreases the transmission torque of the release clutch to a predetermined slope.
The method according to claim 1
In the first step, the controller controls the torque of the vehicle driving source so that the transmission input torque decreases with a constant slope based on an absolute value.
The method according to claim 1
In the second step, the controller controls the hydraulic braking according to the hydraulic braking torque determined from the total braking torque during vehicle deceleration and the torque of the release clutch.
The method of claim 4
The hydraulic braking torque in the second step is determined so that the sum of the torque of the release clutch becomes a value that satisfies the total braking torque.
The method according to claim 1
In the second step, wherein the controller is as a transmission input speed above target speed _{'N Mj - (ΔN M)} B' ( wherein, N _Mj is the synchronization speed set for the running stage, (ΔN _{M) B} is to be set in advance A control method for shifting a hybrid vehicle, comprising controlling a speed of a vehicle driving source to follow a positive value as a margin value.
The method according to claim 1
In the third step, the controller determines that the release clutch has reached the release state when the state of'the absolute torque value of the release clutch ≤ set value' is continuously maintained for a predetermined set time. Control method when shifting.
The method of claim 4, 5, or 7
The torque of the release clutch is a transmission torque estimation amount obtained by estimating the transmission torque of the release clutch, and the transmission torque estimation amount is determined from a transmission input shaft rotation speed and a clutch torque that is a control command value for the release clutch. Control method.
The method of claim 8
The transmission torque estimation amount is a control method during shifting of a hybrid vehicle, characterized in that calculated by the following equation.
Equation: T _{R_est} = sign(N _M -N _Mj )μ|TC _R |
(Where, T _{R_est} is the estimated amount of transmission torque of the release clutch, N _M is the transmission input shaft rotation speed, N _Mj is the set synchronous speed of the driving stage, μ is the clutch friction coefficient, and TC _R is the clutch torque, which is the control command value for the release clutch, sign(x) is a function that indicates a value of +1 when x> 0, a function that indicates a value of -1 when x <0, and | | is a symbol that indicates an absolute value)
The method according to claim 1
In the third step, the controller controls the speed of the vehicle drive source so that the transmission input shaft rotational speed follows the set synchronous speed of the driving stage after terminating the vehicle drive source speed control for shifting to the neutral stage. Control method at the time of shifting of a hybrid vehicle.
The method according to claim 1,
After the start of the third step and in a state where the shift to the neutral stage is completed, the controller maintains the total braking torque during vehicle deceleration at the same value as before the shift, but performs hydraulic braking control so that the total braking torque is satisfied only with the hydraulic braking torque. A method for controlling the shift of a hybrid controller, characterized in that performing.
The method according to claim 1,
In the second step, the controller determines that slip of the release clutch has occurred when a difference between the transmission input shaft rotation speed and the set synchronous speed of the driving stage by a predetermined level or more occurs.

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