KR102598561B1 - Control method for shift of hybrid electric vehicle - Google Patents

Abstract

The present invention relates to a control method when shifting gears in a hybrid vehicle. When the driver operates the shift lever during deceleration of the hybrid vehicle and the gear range of the transmission changes from the drive range (D range) to the neutral range (N range), the vehicle's The main purpose is to provide a control method when shifting that can appropriately maintain a sense of deceleration. To achieve the above purpose, before clutch slip, brake coordination control is performed to generate hydraulic braking force based on the amount of regenerative braking, and after slip, brake coordination control is performed to generate hydraulic braking force based on clutch transmission torque. A method for controlling gear shifting of a hybrid vehicle is disclosed.

Description

Control method for shift of hybrid electric vehicle}

The present invention relates to a control method when shifting gears in a hybrid vehicle, and more specifically, to a control method that can maintain a sense of vehicle deceleration when shifting to a transmission neutral range (N range) during deceleration of a hybrid vehicle.

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

Hybrid vehicles can output optimal torque and maximize fuel efficiency depending on how the engine and motor operate harmoniously during the driving process.

Hybrid vehicles can have a drivetrain with various structures. The TMED (Transmission Mounted Electric Device) hybrid system, which connects the engine and motor through an engine clutch and connects a transmission to the motor output side, is known.

In the TMED hybrid system, a 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 rotation speed (i.e. 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 motor and transmits it to the driving wheel through the drive shaft. The transmission in a hybrid vehicle is an automatic transmission (AT) or a dual clutch transmission (Dual Clutch Transmission). DCT) may be used.

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

Additionally, when the vehicle is braking or coasting due to inertia, a regenerative mode is performed in which the vehicle's kinetic energy is recovered through the motor to charge the battery.

In regenerative mode, the vehicle's kinetic energy is transmitted to the motor through the vehicle wheels, and at this time, the motor operates as a generator and charges the battery through the inverter.

Meanwhile, when a TMED hybrid vehicle is equipped with a transmission that physically disengages the gear when in N gear (neutral gear) and regenerative braking is performed while the vehicle is decelerating (while braking), the driver operates the shift lever to change the transmission to N gear. In this case, it is difficult to maintain a sense of vehicle deceleration, and impacts are likely to occur.

Normally, for safety reasons, the power transmission from the transmission is cut off mechanically or electronically when in N gear. In this case, if the power transmission is mechanically cut off, vehicle control becomes difficult and drivability becomes vulnerable.

In particular, when the clutch in the transmission is disengaged, power is cut off at the rear end of the motor, so the motor speed rapidly decreases due to negative motor torque, and the sudden change in clutch transmission torque causes a loss of power experienced during braking of a conventional internal combustion engine vehicle. The impact of not being able to do something can occur and become a source of dissatisfaction.

In addition, the brake controller (Brake Control Unit, BCU) controls the generation of hydraulic braking torque excluding the regenerative braking amount to satisfy the required braking torque. When the transmission enters N gear and the clutch transmission torque rapidly decreases, The hybrid controller (Hybrid Control Unit, HCU) relatively slowly increases the torque command (motor torque command) for the vehicle's driving source, and the brake controller applies brake hydraulic pressure based on this, causing the vehicle to fail to maintain a constant sense of deceleration and bounce. An exit phenomenon may occur.

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

In other words, in a situation where the clutch is released and slip occurs, even though the output torque is unrelated to the input torque, brake control only considers the regenerative braking torque, making it impossible to secure a certain deceleration rate.

In addition, when control is terminated in this way, it is not easy to predict changes in motor speed, which is disadvantageous in linking with the next control.

Figure 1 is a diagram illustrating the prior art and illustrates a control state when the driver operates the shift lever to N while the vehicle is decelerating.

Figure 1 shows two diagrams, with diagrams shown on the upper and lower sides, respectively. In the upper diagram, the vertical axis represents speed (ω) and 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 area below represents the negative (-) torque area, and the area above represents the positive (+) torque area.

In addition, in the diagram of FIG. 1, N _Mj represents the synchronous speed in the previous driving range (D gear) N, N _M represents the transmission input shaft rotation speed (transmission input speed), and in the TMED hybrid system, the transmission input shaft rotation speed ( N _M ) is equal to the speed of the motor that drives the vehicle.

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

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

Additionally, in Figure 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 the transmission, and transmission torque (T _R ) may refer to the torque value transmitted by the clutch when the clutch is controlled according to the torque command value. It could mean something.

In other words, if the clutch torque (TC _R ) is a command value related to the torque output by the controller for clutch control, the transfer torque (T _R ) can be said to be the torque in the clutch that appears as a result of control according to the command value.

Referring to FIG. 1, when the shift range is changed from D to N by the driver's shift lever operation while regenerative braking is performed while the vehicle is braking and decelerating, the transmission input shaft rotation speed (transmission input speed) (N _M ) You can see that is rapidly falling.

In addition, when the driver operates the shift lever in the vehicle to change the gear range of the transmission from D to N, the release clutch is released so that the power is cut off (clutch release). At this time, regenerative braking is not possible, so the required Increase the hydraulic braking torque (T _B ) to satisfy the required braking torque.

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

In addition, when the gear shift of the transmission is changed from D to N, power is cut off, so as shown in FIG. 1, the transmission input torque (transmission input shaft torque) (T _i ) and the transmission output torque (transmission output shaft torque) (T _o ) will decrease based on absolute value in the negative (-) torque region, 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 increases based on its absolute value in the negative torque region, that is, as a negative (-) value. In the drawing, you can see a state of rapid decline (decrease).

When shifting to N gear is completed, the regenerative braking torque becomes 0 Nm, so the total braking torque required during deceleration is satisfied with only the hydraulic braking torque (T _B ).

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

In addition, it is difficult to predict changes in motor speed after control, resulting in disadvantages in the next control.

Therefore, the present invention was created to solve the above problems, and the driver operates the shift lever during deceleration of the hybrid vehicle to change the gear stage of the transmission from the driving range (D range) to the neutral range (N range). The purpose is to provide a control method when shifting that can appropriately maintain the sense of deceleration of the vehicle.

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

Additionally, in the second step, the controller controls hydraulic braking according to 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 sets the transmission input speed to the target speed as 'synchronous speed - (ΔN _M ) _B ' (where (ΔN _M ) _B is a preset margin and is a positive (+) value) It is characterized by controlling the speed of the vehicle drive source to follow.

Accordingly, according to the control method when shifting gears of a hybrid vehicle according to the present invention, it is possible to secure a uniform feeling of vehicle deceleration without shock when shifting to N gear during deceleration (during braking).

In other words, before clutch slip, brake coordination control is performed to generate hydraulic braking force based on the amount of regenerative braking, and after slippage, brake coordination control is performed to generate hydraulic braking force based on clutch transmission torque, thereby reducing the clutch transmission torque. It becomes possible to secure a uniform sense of deceleration without shock or variation in the sense of deceleration of the vehicle due to sudden changes in .

In addition, it is possible to secure responsiveness even after controlling the rotational speed of the transmission input shaft, which is performed when shifting to N during deceleration (during braking). To ensure responsiveness after shifting, the speed of the vehicle drive source is controlled lower than the synchronous speed in controlling the rotational speed of the transmission input shaft. By performing, it is possible to maintain the vehicle deceleration and have the advantage of being able to quickly respond to subsequent control by converging the vehicle drive source speed to the desired speed in advance.

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

Hereinafter, with reference to the attached drawings, embodiments of the present invention will be described in detail so that those skilled in the art can 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 in the entire specification is said to “include” a certain element, this means that it may further include other elements rather than excluding other elements, unless specifically stated to the contrary.

The present invention relates to a control method when shifting gears in a hybrid vehicle, wherein the driver operates the shift lever during deceleration (during braking) of the hybrid vehicle to change the gear range (shift range) of the transmission from the drive range (D range) to the neutral range (N However, the purpose is to provide a control method when shifting that can appropriately maintain the sense of deceleration of the vehicle when changing to (however).

To this end, an improved control method is disclosed that maintains a uniform sense of vehicle deceleration and controls the motor speed to a desired speed by varying brake coordination control depending on the clutch state of the transmission when changing to a neutral gear during deceleration.

The shift control method of the present invention can be applied to hybrid vehicles in which regenerative braking and hydraulic braking are implemented. For example, it can be applied to TMED hybrid vehicles, and can also be applied to automatic transmission (AT) or dual clutch transmission (DCT). It can be applied to vehicles equipped with it.

In addition, the pre-stop downshift control process of the present invention is performed using known in-vehicle controllers, such as a hybrid controller (Hybrid Control Unit, HCU), a transmission control unit (TCU), a motor controller (Motor Control Unit, MCU), Cooperative control may be performed by a plurality of controllers, such as an Engine Control Unit (ECU) and a Brake Control Unit (BCU), or may be performed by one controller having the integrated functions of these controllers.

Hereinafter, a method for controlling downshifting 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.

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

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

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

For example, status information of the engine controller (ECU) 30 that controls the operation of the engine 90, the transmission controller (TCU) 40 that controls the operation of the transmission 120, and the battery 70 are collected and A battery controller (BMS) 50 that utilizes, provides, and performs control for battery management, a motor controller 60 for driving and controlling the motor 110, and a brake controller (BCU) that performs braking control of the vehicle ( 80) etc. 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 for eco-friendly vehicles, that performs regenerative braking control and hydraulic braking control.

Additionally, the battery 70 is connected to the motor 110 through an inverter (not shown) of the motor controller 60 to enable charging and discharging.

In FIG. 2, reference numeral 130 represents a hydraulic circuit that generates brake hydraulic pressure, and reference numeral 131 represents a wheel brake installed on the vehicle wheel 9 to generate hydraulic braking force (i.e., friction braking force).

The hybrid vehicle is equipped with a hydraulic braking device (friction braking device), and the hydraulic braking device is installed on a hydraulic circuit 130 that generates brake hydraulic pressure and the vehicle wheel 9 to apply brake hydraulic pressure generated in the hydraulic circuit 10. It includes a wheel brake 131 that generates braking force (friction braking force).

The brake controller 80 controls the operation of the hydraulic braking device. It 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 of devices in the vehicle while exchanging information with each other through CAN communication. The upper controller collects various information from lower controllers and transmits control commands to the lower controllers. .

The driving information detection unit indicated by reference numeral 10 in FIG. 2 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 the driver's brake pedal operation status, accelerator pedal operation status, and shift lever operation status, and vehicle status information may include vehicle speed and motor speed.

The driving information detection unit 10 includes an accelerator pedal sensor (APS), which outputs a signal according to the driver's operation of the accelerator pedal, and a brake pedal sensor (Brake Pedal Sensor, BPS), which outputs a signal according to the driver's operation of the brake pedal. , may include a shift detection unit for detecting the position of the shift lever, a vehicle speed detection unit for detecting vehicle speed, and a motor speed detection unit for detecting the motor speed, and these include a hybrid controller 20 and a shift controller 40, and the in-vehicle controller It can be connected to allow input of detection values.

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

That is, the shift controller 40 determines that the gear of the transmission has been operated from D to N by the driver based on 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 of the transmission is operated from D to N. At this time, the control command value for the release clutch, that is, the clutch A command value corresponding to the torque (TC _R ) is output, and 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.

Additionally, the shift controller 40 transmits information about clutch transmission torque to the hybrid controller 20 for hydraulic braking cooperative control, as will be described later.

The hybrid controller 20 performs control to release the transmission input torque (T _i ) to a torque value of 0 Nm when operating in N gear, and transmits the target regenerative braking execution amount (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.

Additionally, the hybrid controller 20 controls the speed of the vehicle drive source, which becomes 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 slip occurs during N-range operation, the hybrid controller 20 performs control to release the transmission input torque (T _i ) until slip is determined, and after slip is judged, based on the target input speed. The transmission input shaft rotation speed (N _M ) is controlled.

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 necessary to control the transmission input shaft rotation speed (N _M ). It is possible to control engine speed along with city motor speed.

The target input speed refers to the set target speed in the driving range (D range) before shifting to N range, 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 Controls the operation of the hydraulic braking device to generate the necessary hydraulic braking force (hydraulic braking torque) during the control process when shifting.

In the present invention, when shifting to N gear, the brake controller 80 performs hydraulic braking control to generate and control hydraulic braking torque based on the target regenerative braking execution amount (torque value) transmitted by the hybrid controller 20. Hydraulic braking control is performed to generate and control hydraulic braking torque based on torque information of the release clutch transmitted by 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 before determining slip, and controls generating hydraulic braking torque based on the torque value of the release clutch after determining slip. Perform.

As described above, the control process according to the embodiment of the present invention can be performed by cooperative control between a plurality of controllers. Hereinafter, the plurality of controllers are divided according to function, and the divided plurality of controllers perform cooperative control. A description will be given of performing a control process according to an embodiment of the invention.

However, not only can a plurality of controllers be collectively described as one controller, but furthermore, one integrated controller can actually perform the control process according to an embodiment of the present invention.

Figure 4 is a flowchart showing the control process when changing the N range of a hybrid vehicle according to an embodiment of the present invention, and Figure 5 is a diagram illustrating a control state when changing the N range of a hybrid vehicle according to an embodiment of the present invention. It shows the motor speed and torque status while shifting from D to N.

In addition, FIG. 6 is an enlarged view of the circled portion of FIG. 5 and shows an enlarged portion of a speed control state for maintaining a sense of deceleration when changing from D to N of a hybrid vehicle.

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

And, Figure 5 is a diagram in contrast to Figure 1 illustrating the prior art, and like Figure 1, two diagrams are shown on the upper and lower sides, respectively.

In the upper diagram of FIG. 5, the vertical axis represents speed (ω) and 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, the area below the horizontal axis (TQ = 0Nm) represents a negative (-) torque area, and the area above represents a positive (+) torque area.

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

Additionally, 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 is coupled to transmit power in the drive range before shifting when shifting from the drive range (D range) to the neutral range (N range). This refers to the release clutch, which is the clutch that must be released when shifting from drive to neutral.

In addition, in Figure 5, T _o represents the transmission output torque (i.e., transmission output shaft torque), T _i represents the transmission input torque (i.e., transmission input shaft torque), T _T represents the total braking torque based on the transmission output shaft, and T _B is Indicates 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 ) may mean the torque transmitted by the clutch when the clutch is controlled according to the torque command value. It may mean torque value.

In other words, if the clutch torque (TC _R ) is a command value related to the torque output by the transmission controller 40 for clutch control, the transmission torque (T _R ) can be said to be the torque in the clutch that appears as a result of control according to the command value. there is.

Additionally, in the present invention, the transmission output torque (T _o ) is equal to the transmission torque (T _R ) of the release clutch.

In Figure 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 in the TMED hybrid system, the transmission input torque (T _i ) is the torque of the vehicle drive 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 and the hydraulic braking torque T _B , and the transmission torque T _R and the transmission output torque T _o are torques that appear as a result of control.

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

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

This transmission output shaft reference torque may be a torque directly obtained, estimated, or calculated based on the transmission output shaft in addition to the converted equivalent torque.

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

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

That is, as shown in FIG. 4, the shift controller 40 receives a shift command to N gear according to the driver's operation while the vehicle is decelerating and determines that there is an N gear operation. This determination is made by the shift controller 40. This can be done by receiving a signal from the shift detection unit of the driving information detection unit 10, which detects the position of the shift lever.

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

In FIG. 5, the A-B section is an input torque reduction section, and in the control stage of the input torque reduction section, control to release the release clutch in the engaged state begins in the shift controller 40.

At this time, the shift controller 40 gradually reduces and outputs the clutch torque (TC _R ) command value of the release clutch, and the release clutch is controlled according to the clutch torque (TC _R ) command, so that the torque in the release clutch, that is, the release clutch The transmission torque (T _R ) gradually decreases.

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

In addition, even if the torque of the release clutch (T _R ) 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 the target regenerative braking is executed, which is a negative (-) torque value. If the amount is increased, the transmission input torque (T _i ) level at the time of clutch slip occurrence can be maintained close to the 0 torque (0 Nm) level, and the sense of deceleration of the vehicle can be improved through cooperative control with the brake controller 80. It is possible to adjust it.

When the hybrid controller 20 receives a signal from the shift controller 40 at point A indicating that the driver has shifted to N gear, it reduces the transmission input torque (T _i ) and performs cooperative control based on the target regenerative braking amount. The reduction amount of the transmission input torque (T _i ) may be set to ensure stable responsiveness to the brake hydraulic pressure generated and controlled by the brake controller 80.

In the AB section, the transmission input torque (T _i ) is a negative (-) torque applied through regenerative braking, so reducing the transmission input torque (T _i ) as described above means reducing the transmission input torque (T _i ) to a negative (-) torque. ) means reducing the torque range based on its absolute value, and actually increasing the transmission input torque upward in the drawing in FIG. 5 from a negative (-) value to a direction closer to 0, that is, to a gradually larger value. means that

In addition, reducing the transmission input torque (T _i ) based on its absolute value means releasing the transmission input torque (T _i ), and in this way, before slip occurs in the release clutch, the hybrid controller 20 reduces the transmission input torque. (T _i ) is controlled to be released.

In the AB section, the brake controller 80 performs control to generate and apply hydraulic braking torque (T _B ) by the amount of decrease (increase in the drawing) based on the absolute value of the transmission input torque (T _i ). In this case, 'total braking torque = It is controlled so that hydraulic braking torque that satisfies the relationship of 'target regenerative braking execution amount + hydraulic braking torque' is generated and applied.

Regarding the process of obtaining the target amount of regenerative braking during deceleration (during braking) in the hybrid controller 20, a person skilled in the art will be asked in the cooperative control process to ensure that the total braking torque required during braking is satisfied by the regenerative braking torque and hydraulic braking torque. Since this is a well-known technical matter, detailed explanation will be omitted.

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

Next, the condition in which slip of the release clutch occurred can be set as an entry condition for the BC section, and specifically, the condition in which a decrease in the transmission input shaft rotation speed (N _M ) is detected is set to determine the occurrence of slip in the release clutch. It can be.

More specifically, in a TMED hybrid vehicle, the transmission input shaft rotation speed (N _M ) becomes the speed of the motor connected to the transmission input side, so the motor speed detected by the motor speed detection unit has a difference of more than a certain level from the synchronous speed (N _Mj ). If it is in a reduced state, it can be set to enter the BC section.

At this time, the hybrid controller 20 receives the signal from the motor speed detector, determines that the entry conditions for the B-C section are satisfied, and then communicates with other controllers to perform the control process for the B-C section.

The BC section is a section where brake coordination 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 control to release the release clutch following the A-B section. However, from point B, it can be said that the release clutch has slipped.

In the BC section, like the AB section, the shift controller 40 gradually reduces and outputs the command value of the clutch torque (TC _R ) of the release clutch, thereby controlling the transmission torque (T _R ) of the release clutch to gradually decrease.

In this way, in reducing the torque of the release clutch (TC _R ,T _R ) in the BC section, the shift controller 40 reduces the torque of the release clutch (TC _R ,T _R ) at a certain slope, and the slope is determined by the brake controller It is set to a level that ensures the responsiveness of brake hydraulic pressure in cooperative control with (80).

Ultimately, in the B-C section, release is completed after slip of the release clutch occurs.

In addition, the shift controller 40 calculates the 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 transmission torque estimate by estimating the actual transmission torque and provides it to the brake controller 80 for cooperative control. Transmit.

The equation for calculating the transmission torque estimate is as follows.

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

Here, T _{R_est} represents the estimated amount of transmission torque, N _M represents the transmission input shaft rotation speed, and N _Mj represents the synchronous speed in the driving range before shifting.

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

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

As in equation (1), the transmission torque estimate (T _{R_est} ) calculated from the transmission input shaft rotation speed (N _M ) and clutch torque (TC _R ) can be calculated, and this transmission torque estimate (T _{R_est} ) is the actual transmission output shaft Therefore, in the present invention, when the shift controller 40 calculates the transmission torque estimate (T _{R_est} ) and transmits it to the brake controller 80, the brake controller 80 calculates the brake hydraulic pressure based on the transmission torque estimate (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 set target speed, that is, 'N _Mj - (ΔN _M ) _B ', and at this time, controls the vehicle drive source speed. For this reason, the hybrid controller 20 can 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.

In the BC section, if the vehicle drive source speed (same as the motor speed), which becomes the transmission input shaft rotation speed (N _M ), is controlled to be greater than the synchronous speed (N _Mj ), a feeling of acceleration rather than deceleration may be created, so the synchronous speed (N _Mj) ), but set a positive (+) value (ΔN _M ) _B as a margin value, and speed control is performed with some margin so that the motor speed (N _M ) follows the value of 'N _Mj - (ΔN _M ) _B '. Conduct.

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

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

Generally, in N gear, speed is controlled until the transmission input shaft rotation speed (N _M ) reaches 0 rpm.

In contrast, in the present invention, as shown in the diagram of FIG. 5, even if the driver operates the shift lever to N, which is the neutral stage, the driving range (D stage) is assumed in N range to follow the synchronous speed (N _Mj ). Controls the speed of the vehicle's drive source.

In particular, in the BC section, instead of waiting until the release clutch is completely released, the transmission input shaft rotation speed (N _M ) is controlled in advance to be close to the synchronous speed (N _Mj ), thereby lowering the transmission input shaft rotation speed (transmission input speed). minimize.

At the same time, in the BC section, the brake controller 80 applies hydraulic braking torque considering the torque change of the release clutch, which is information received from the shift controller 40. At this time, the torque of the release clutch is used by the shift controller ( The transmission torque estimate (T _{R_est} ) transmitted in 40) can be used.

That is, after the brake controller 80 receives the transmission torque estimate (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 transmission torque estimate, The 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 torque based on the transmission output shaft and represents the estimated transmission torque of the release clutch, and T _B is also the torque based on the transmission output shaft and is 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 amount of transmission torque (T _{R_est} ) of the release clutch as shown in equation (2), and the determined target Hydraulic braking is controlled so that the 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, especially the transmission torque estimate (T _{R_est} ), is equal to the transmission output torque (transmission output shaft torque) (T _o ), and in equation (2), the transmission output torque ( 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 ), so the total braking torque can be maintained constant throughout the gear shift.

Referring to FIG. 5, when controlling the speed of the vehicle drive source in the BC section, the transmission input torque (T _i ) exceeds 0 Nm and becomes an amount (T i ) in a form corresponding to the change in vehicle drive source speed and transmission input shaft rotation speed (transmission input speed). You can see that it is controlled to have a torque value of +).

In addition, when speed control for the vehicle drive source is terminated after point C, the transmission input torque (T _i ) is controlled to 0 Nm after N gear shifting is completed, 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 point C.

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

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

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

The shift controller 40 requests the hybrid controller 20 to complete the shift at a point C when the absolute value of the release clutch torque becomes less than the set value, which is a small value. Accordingly, the hybrid controller 20 performs a shift completion request for N-range shifting. Speed control of the vehicle drive source ends.

As described above, in a situation where the transmission torque (T _R ) of the release clutch is reduced and power transmission is blocked, the speed control for N-range shifting is terminated and the next control is transitioned. The transmission input shaft rotation speed (N _M ) in the subsequent N range can be controlled to match the synchronous speed (N _Mj ) in the driving range before the shift, as shown in the diagram of FIG. 5 .

Referring to FIG. 5, when the vehicle is decelerated (during braking) and there is an operation to the neutral stage N, the driving stage (D stage) is assumed and the speed is controlled to follow the driving stage synchronous speed (N _Mj ), Before point C, speed is controlled by setting 'N _Mj - (ΔN _M ) _B ' as the synchronous speed, but after point C and after shifting to N gear is completed, speed is controlled by setting N _Mj as the synchronous speed. can see.

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

In this way, according to the control method when shifting to N gear of a hybrid vehicle according to the present invention, it is possible to secure a uniform feeling of vehicle deceleration without shock when shifting to N gear during deceleration (during braking).

In other words, before clutch slip, brake coordination control is performed to generate hydraulic braking force based on the amount of regenerative braking, and after slippage, brake coordination control is performed to generate hydraulic braking force based on clutch transmission torque, thereby reducing the clutch transmission torque. It becomes possible to secure a uniform sense of deceleration without shock or variation in the sense of deceleration of the vehicle due to sudden changes in .

In addition, it is possible to secure responsiveness even after controlling the rotational speed of the transmission input shaft, which is performed when shifting to N during deceleration (during braking). To ensure responsiveness after shifting, the speed of the vehicle drive source is controlled lower than the synchronous speed in controlling the rotational speed of the transmission input shaft. By performing, it is possible to maintain the vehicle deceleration and have the advantage of being able to quickly respond to subsequent control by converging the vehicle drive source speed to the desired speed in advance.

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 can be made by those skilled in the art using the basic concept of the present invention as defined in the following patent claims. It is also included in the scope of rights of the present invention.

9: Vehicle wheel 10: Driving information detection unit
20: Hybrid controller (HCU) 30: Engine controller (ECU)
40: Transmission 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 command to shift from the transmission drive range to the neutral range during regenerative braking during vehicle deceleration, it starts control to reduce the transmission torque of the release clutch in the clutch release direction, and the transmission input torque is maintained in the negative torque region. A first step of controlling the torque of the vehicle drive source connected to the transmission input side to decrease based on the absolute value;
When the controller determines that slip of the release clutch occurs, it continues to reduce the transmission torque of the release clutch to release the release clutch, and controls the vehicle drive source speed for shifting to neutral so that the transmission input speed follows the set target speed. A second step of performing; and
A third step of terminating vehicle drive source speed control for shifting to the neutral range when the controller determines that the release clutch has reached a released state,
In the first step, the controller controls hydraulic braking according to hydraulic braking torque determined from the total braking torque during vehicle deceleration and the target regenerative braking execution amount.
In claim 1,
In the first step, the controller reduces the transmission torque of the release clutch to a certain slope.
In claim 1
In the first step, the controller controls the torque of the vehicle drive source so that the transmission input torque decreases at a constant slope based on the absolute value.
In claim 1
In the second step, the controller controls hydraulic braking according to hydraulic braking torque determined from the total braking torque during vehicle deceleration and the torque of the release clutch.
In claim 4
A control method when shifting gears in a hybrid vehicle, characterized in that the hydraulic braking torque in the second step is determined so that the sum of the torque of the release clutch is a value that satisfies the total braking torque.
In claim 1
In the second step, the controller sets the transmission input speed to 'N _Mj - (ΔN _M ) _B ' as the target speed (where N _Mj is the set synchronous speed of the driving range, and (ΔN _M ) _B is a preset A control method when shifting gears in a hybrid vehicle, characterized in that the speed of the vehicle drive source is controlled to follow a margin (a positive value as a margin value).
In claim 1
In the third step, the controller determines that the release clutch release state has been reached when the state of 'absolute torque of the release clutch ≤ set value' is continuously maintained for a predetermined set time. Control method when shifting.
In claim 4, claim 5, or claim 7
The torque of the release clutch is a transmission torque estimate obtained by estimating the transmission torque of the release clutch, and the transmission torque estimate is determined from the transmission input shaft rotation speed and the clutch torque, which is a control command value for the release clutch. Control method.
In claim 8
A control method for shifting gears in a hybrid vehicle, wherein the estimated amount of transmission torque is calculated by the following equation.
Expression: T _{R_est} = sign(N _M -N _Mj )μ|TC _R |
(Here, T _{R_est} is the estimated 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, TC _R is the clutch torque which is the control command value for the release clutch, sign(x) is a function that represents the value of +1 when x > 0 and the value of -1 when x < 0, | | is a symbol representing the absolute value)
In claim 1
In the third step, the controller terminates the vehicle drive source speed control for shifting to the neutral range and then controls the speed of the vehicle drive source so that the transmission input shaft rotation speed follows the set synchronous speed of the drive range. Control method when shifting gears in a hybrid vehicle.
In claim 1,
After the third step is started and the shift to the neutral stage is completed, the controller maintains the total braking torque during vehicle deceleration at the same value as before shifting, but performs hydraulic braking control to satisfy the total braking torque only with hydraulic braking torque. A control method for shifting gears of a hybrid controller, characterized in that:
In claim 1,
In the second step, the controller determines that slip of the release clutch has occurred when the rotational speed of the transmission input shaft differs from the set synchronous speed of the drive range by a certain level or more.

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