Methods for controlling the movement of electric vehicles

Abstract

This invention provides a driving control method for an electric vehicle. The method includes generating a motor torque command using a basic torque command and a virtual shift intervention torque for generating a realistic shift feel while the electric vehicle is in motion. The generated motor torque command is used to operate the motor used to drive the electric vehicle to generate a realistic shift feel. During the generation of the realistic shift feel, at least a portion of the time during which the realistic shift feel is generated, enhanced control of the motor operation is performed to generate a motor torque exceeding the permissible torque of the motor, thereby simultaneously performing the generation and enhancement control of the realistic shift feel.

Description

TECHNICAL FIELD

[0001] The present application relates to a travel control method for an electric vehicle, and more particularly, to a travel control method for an electric vehicle using an enhanced application control strategy that can improve both the drivability and the acceleration performance of the electric vehicle. BACKGROUND

[0002] As is well known, an electric vehicle (EV) uses one or more electric motors for propulsion. The drive system of an electric vehicle includes an electric motor that serves as a driving power source, a battery for supplying electric power to the electric motor, an inverter for driving the electric motor, and a reduction gear that reduces the rotational power of the electric motor and transmits the reduced rotational power to drive wheels. The electric motor is connected to the battery via the inverter, so that the battery is charged or discharged according to the operating mode of the electric motor.

[0003] During the driving operation of the electric motor, the inverter converts a direct current (DC) current into an alternating current (AC) current and supplies the resulting AC current to the electric motor through a cable. Conversely, during the regenerative power generation operation of the electric motor, the inverter converts the AC current generated by the electric motor (which operates as a generator) into a DC current and supplies the resulting DC current to the battery to charge the battery.

[0004] Unlike an internal combustion engine vehicle, an electric vehicle does not use a multi-gear transmission. Instead, the electric vehicle uses a reduction gear that is disposed between the electric motor and the drive wheels and uses a fixed transmission ratio. The reason for this is as follows. An internal combustion engine has a relatively wide energy efficiency distribution range according to the operating point, and provides high torque only at high speeds. In contrast, an electric motor has a relatively narrow energy efficiency distribution range according to the operating point, and can provide high torque even at low speeds only by its own characteristics.

[0005] On the other hand, the acceleration performance of an electric vehicle depends on the torque capacity of the electric motor. The torque capacity of the electric motor is affected by the performance of the inverter that controls the electric motor, the power supply capacity of the battery, and the maximum capacity of power electronics (PE) components, etc. In general, the maximum capacity is limited so that it is used within a range that ensures safety, and this limit is adjusted to maintain a thermodynamic equilibrium in a normal state. Therefore, when the load is at or exceeds this limit, a torque higher than the rated torque can be generated, which can increase the acceleration. However, especially the related PE components can be overheated, which can cause a fire of the vehicle.

[0006] In this context, the term "normal state" means a same condition or state maintained for a sufficiently long period of time. Therefore, the maximum capacity of each PE component is conservatively set. In other words, the maximum capacity is set assuming a normal state to be lower than the instantaneous performance. If it is assumed that the PE component is used only for a short time, i.e., the PE component is not used in the normal state, its instantaneous load tolerance can be increased to be higher than the capacity set in the normal state. The instantaneous increase in the output of each PE component (e.g., a motor) for this purpose is referred to as "boosting".

[0007] However, if boosting is performed to the maximum extent while the electric vehicle is running, it is necessary to alternately perform boosting operation and normal operation. However, this can cause a difference from the driver's expectation in terms of the acceleration feeling or the driving performance of the electric vehicle. Specifically, when boosting is frequently alternated with normal operation, the driving performance is degraded. For this reason, there is a need for a boosting application strategy that uses boosting function without degrading the driving performance. SUMMARY

[0008] The present application provides a boosting application control strategy that can improve both the driving performance and the acceleration performance of an electric vehicle. Another object of the present application is to provide a method of controlling the running of an electric vehicle by using a boosting application control strategy.

[0009] According to an aspect of the present application, a running control method of an electric vehicle can include enabling a controller to generate a motor torque command using a basic torque command and a virtual shift intervention torque for generating a real shift feeling while the electric vehicle is driven, and enabling the controller to operate a motor for driving the electric vehicle according to the generated motor torque command, thereby enabling generation of the real shift feeling; wherein, while the real shift feeling is generated, boosting control for operating the motor is performed so as to generate a motor torque exceeding a permissible torque of the motor for at least a part of the time during which the real shift feeling is generated, thereby enabling the generation of the real shift feeling and the boosting control to be performed in conjunction.

[0010] With the running control method of an electric vehicle according to the present application, torque boosting can be performed in conjunction with the implementation of a virtual multi-shift shift feeling in an electric vehicle equipped with a reduction gear. Therefore, the durability condition of the motor can be satisfied, and in addition, a torque higher than the normal torque of the motor can be generated, thereby increasing the acceleration. Furthermore, at a point in time at which a process for implementing the virtual multi-shift shift feeling can be expected to be performed, an instantaneous boosting operation can be performed. Therefore, the difference feeling of the driver during driving can be reduced. Furthermore, the driving performance can be improved while the acceleration performance can be increased. BRIEF DESCRIPTION OF DRAWINGS

[0011] The above and other objects, features and advantages of the present application will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings in which:

[0012] Figure 1 a block diagram showing the configuration of the apparatus for controlling an electric vehicle according to the present application;

[0013] Figure 2 a block diagram showing input and output variables of a virtual shift model according to the present application and intermediate variables for implementing virtual shift function of virtual shift;

[0014] Figure 3A and Figure 3B a diagram showing a shift schedule map for determining a virtual target gear according to the present application;

[0015] Figure 4 a diagram showing one shift schedule map which can be used for upshift and downshift according to the present application;

[0016] Figure 5 a diagram showing a maximum motor torque characteristic curve which varies with motor speed and a limit torque of each virtual gear according to the present application, which can be calculated to reflect gear ratio information of each gear by Figure 5

[0017] Figure 6 a diagram showing an example of a virtual shift intervention torque characteristic curve according to the present application;

[0018] Figure 7 a flowchart showing a method for implementing enhancement by real shift feel together according to the present application;

[0019] Figure 8 a diagram showing an excess portion and a deficiency portion of a limit torque of each virtual gear by comparison with a maximum motor torque characteristic curve according to an exemplary embodiment of the present application;

[0020] Figure 9 a reference diagram showing a change in vehicle acceleration with time when a shift is performed in a vehicle equipped with a real transmission, which represents an acceleration generated when a shift is performed in an electric vehicle equipped with a real transmission as Figure 9 shown in FIG. 6;

[0021] Figure 10 a diagram showing a state of a virtual shift intervention torque for implementing a real shift feel which is applied when accelerating according to the present application, which shows an acceleration simulation when a shift is performed in an electric vehicle implementing a virtual gear; and

[0022] Figure 11 and​Figure 12 Each shows an example of adjusting the magnitude of the push feeling when creating a real gear shift feeling according to the present application. DETAILED DESCRIPTION

[0023] It should be understood that the term "vehicle" or "vehicular" or other similar terms as used herein generally include motor vehicles such as passenger cars, sport utility vehicles (SUVs), large passenger vehicles, various commercial vehicles, including buses, trucks, etc., boats and ships, aircraft, etc., and includes hybrid vehicles, electric vehicles, plug-in hybrid electric vehicles, hydrogen-powered vehicles, and other alternative fuel vehicles (e.g., those powered by fuels other than petroleum products). As used herein, a hybrid vehicle is a vehicle having two or more sources of power, such as a vehicle having both gasoline power and electric power.

[0024] While the example embodiments are described as using a plurality of units to perform the example processes, it should be understood that the example processes can also be performed by one or more modules. Further, it should be understood that the term controller / control unit refers to a hardware device that includes a memory and a processor, and is specifically programmed to perform the processes described herein. The memory is configured to store modules, while the processor is specifically configured to execute the modules to perform one or more processes described further below.

[0025] The terminology used in the herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. As used herein the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0026] The term "about" as used herein is understood as being within the normal tolerances of the art, for example within two standard deviations of the mean. "About" can be understood to be within 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0.5%, 0.1%, 0.05%, or 0.01% of the stated value. Unless the context clearly indicates otherwise, all numerical values provided herein are modified by the term "about."

[0027] Embodiments of the present application will be described in detail below with reference to the attached drawings, so that those skilled in the art to which the present application pertains can practice the present application without undue experimentation. However, the present application is not limited to the exemplary embodiments to be described below, but can be modified and changed.

[0028] When the expression "comprising a component" is used throughout the specification, unless otherwise specifically indicated, the expression means "further comprising any other component" rather than "excluding any other component". The present application provides an enhanced application control method capable of improving both the driving performance and the acceleration performance of an electric vehicle, and provides a travel control method of an electric vehicle using the enhanced application control method. Thus, a method is provided in which a function to realize a real shift feeling in an electric vehicle and a function to execute an electric motor enhancement mode are executed in conjunction with each other, and thus the instantaneous enhancement torque is effectively utilized so that the driver does not feel a difference.

[0029] Generally, the maximum allowable charge torque and the maximum allowable discharge torque of an electric motor (i.e., a drive motor) for driving an electric vehicle are determined with reference to a normal state. Thus, when the electric motor is operated for a short time, a torque higher than the maximum allowable charge torque and the maximum allowable discharge torque (which are determined with reference to the normal state) is generated for the short time. In other words, the electric motor torque is temporarily (i.e., for a predetermined short time or less) increased to a torque higher than the permissible torque. This increase is referred to as "enhancement" of the electric motor.

[0030] When the function to realize a real shift feeling, which is based on a rhythmic feeling of accelerating and decelerating the vehicle and is generated by the feeling obtained through a virtual multi-gear transmission, is executed in conjunction with such inherent electric motor enhancement in an electric vehicle, the durability requirements of the electric motor are satisfied, and a torque greater than the normal torque of the electric motor is generated, thereby increasing the acceleration of the vehicle. Furthermore, the control can be executed so that the instantaneous enhancement operation is executed at a time point at which it is predictable that such operation will be executed. Thus, the driving difference felt by the driver is reduced.

[0031] The function to realize a real shift feeling, which is based on a rhythmic feeling of accelerating and decelerating the vehicle and is generated by the feeling obtained through a virtual multi-gear transmission, is executed in conjunction with such inherent electric motor enhancement in an electric vehicle, the durability requirements of the electric motor are satisfied, and a torque greater than the normal torque of the electric motor is generated, thereby increasing the acceleration of the vehicle. Furthermore, the control can be executed so that the instantaneous enhancement operation is executed at a time point at which it is predictable that such operation will be executed. Thus, the driving difference felt by the driver is reduced.

[0032] However, when a real shift feeling is generated during running of the electric vehicle, that is, when a real shift feeling is realized in a virtual shift situation (for example, a situation in which a shift is performed in a vehicle equipped with a multi-speed transmission), the vehicle is caused to have a discontinuous point of acceleration and deceleration in drivability during realization of the real shift feeling.

[0033] Effective use of the discontinuous point of acceleration and deceleration of the vehicle in drivability can associate a corresponding time point with the discontinuous point at which enhancement is to be applied and at which enhancement is not to be applied. With this association, enhancement can be effectively and naturally performed. Furthermore, satisfactory drivability of the vehicle can be ensured. A virtual shift function of an electric vehicle will be described below to help understanding of the present application.

[0034] In the following description, the electric motor denotes a drive electric motor that drives a vehicle. According to the present application, the vehicle that is a control target is an electric vehicle equipped with a reduction gear instead of an internal combustion engine (a conventional engine) and a multi-speed transmission. As described above, unlike the existing vehicle equipped with the internal combustion engine, a typical electric vehicle (electric motor drive vehicle) driven by the electric motor does not use the multi-speed transmission. Instead, in the typical electric vehicle, the reduction gear using a fixed gear is provided between the electric motor and the drive wheels.

[0035] The absence of the multi-speed transmission provides an advantage that no discontinuity in drivability occurs when a shift is performed, thus ensuring smoothness in drivability. However, a driver who likes to feel a real touch, fun, excitement, responsiveness, and the like (which can be provided by the multi-speed transmission) during driving can feel bored. Therefore, in the electric vehicle equipped with the reduction gear instead of the multi-speed transmission, a technique is required that enables the driver to feel the real touch, fun, excitement, responsiveness, and the like (which can be provided by the multi-speed transmission).

[0036] In the case where the driver likes to feel the real touch, fun, excitement, responsiveness, and the like (which can be provided only by the multi-speed transmission), the function of realizing the real shift feeling enables the driver to feel the desired feeling in the same vehicle without going to drive another vehicle. Therefore, the marketability of the electric vehicle and differentiation marketing can be improved.

[0037] In the existing electric vehicle, the driver cannot control the gear position, and only through the speed and accelerator pedal input, the driver can control the operation of the electric vehicle. In addition, if the virtual shift function is implemented in a high-performance vehicle capable of competitive driving, it is helpful for speed regulation around a target, load movement management, etc. during driving. Therefore, in an electric vehicle not equipped with a multi-gear transmission, virtual shift control is performed by using a virtual shift model established in the controller, which controls the drive motor in a manner that generates and implements a virtual multi-gear shift feeling.

[0038] In other words, under virtual shift control, the virtual shift intervention torque and the limit torque for each virtual gear are determined by the input variables through the virtual shift model, and the input items of the virtual shift model are the vehicle driving information collected in the vehicle while the vehicle is driving. The electric motor is operated using the determined virtual shift intervention torque and the limit torque for each virtual gear, and the motor torque command. Therefore, a virtual multi-gear shift feeling is achieved.

[0039] The virtual shift function is used to generate a real shift feeling, so that a multi-gear shift feeling that the driver can only feel when shifting in a vehicle equipped with a multi-gear transmission is simulated when an electric vehicle not equipped with a multi-gear transmission is driving. Therefore, based on preset variables (parameters) associated with the generation of a real shift feeling, and according to the driver's driving input value and the vehicle state, a real shift feeling is generated. Here, the real shift feeling is a feeling that the driver can feel during the process of shifting in a multi-gear transmission by simulating the behavior and movement of the vehicle, and the real shift feeling is generated and implemented by operating the drive motor under virtual shift control. Here, the multi-gear transmission is one of an automatic transmission (AT), a dual clutch transmission (DCT), and an automatic manual transmission (AMT).

[0040] According to the present application, by operating the drive motor, the behavior and movement of the vehicle that occur during the process of performing a shift operation in a vehicle equipped with one of these transmissions are generated and simulated. Therefore, a real shift feeling is provided, and enhanced control is performed while performing control for the real shift feeling.

[0041] Figure 1 A block diagram showing the configuration of the device for controlling an electric vehicle according to the present application is shown, and the configuration of the device performing control for a real shift feeling and enhanced control is shown. The control method according to the present application can include a virtual shift method for generating and implementing a real shift feeling through motor control while the vehicle is driving, the real shift feeling being generated by simulating a multi-gear shift feeling in an existing vehicle equipped with a multi-gear transmission.

[0042] The configuration of the apparatus for performing the virtual shift process is first described. As shown in Figure 1 The control apparatus according to the present application can include a driving information detection unit 12 configured to detect vehicle driving information, a first controller 20 configured to generate and output a torque command based on the vehicle driving information detected by the driving information detection unit 12, and a second controller 30 configured to operate a driving device 41 according to the torque command output by the first controller 20.

[0043] In addition, the control apparatus according to the present application can further include an interactive interface unit 11 for the driver to select and input one of the opening and closing of the virtual shift function of the vehicle. In the following description, the control entities are divided into the first controller 20 and the second controller 30. However, a plurality of controllers or one integrated control component is collectively referred to as a controller. Therefore, it can also be understood that the control process according to the present application is performed by the controller.

[0044] Any apparatus that the driver can open and close the virtual shift function in the electric vehicle can be used as the interactive interface unit 11. Examples of the interactive interface unit 11 include operating devices such as buttons and switches provided in the electric vehicle, and input devices, touch screens, etc. in an audio, video and navigation (ANV) system. The interactive interface unit 11 is connected to the first controller 20. When the driver turns on or off the virtual shift function, a signal for turning on or off the virtual shift function can be input into the first controller 20 through the interactive interface unit 11 accordingly. Therefore, the first controller 20 can be configured to detect whether the driver turns on or off the virtual shift function.

[0045] According to the present application, only in the case where the driver turns on the virtual shift function through the interactive interface unit 11, the virtual shift function that generates and realizes the real shift feeling when the electric vehicle is driven can be performed. In addition, although not shown in Figure 1 the driver can turn on or off the virtual shift function through a mobile device (not shown) instead of the interactive interface unit 11, which is an input device for the vehicle provided in the electric vehicle.

[0046] The mobile device can be communicably connected to an apparatus within the vehicle, such as the first controller. Therefore, a communication interactive interface (not shown) for input and output can be used to establish a communication connection between the mobile device and the first controller 20. The driving information detection unit 12 can be configured to detect vehicle driving information required to generate a motor torque command in the electric vehicle. Here, the vehicle driving information can include the driver's driving input information and vehicle state information.

[0047] According to an exemplary embodiment of the present application, the driving information detecting unit 12 can include an accelerator pedal detecting unit configured to detect accelerator pedal input information according to the driver's operation of the accelerator pedal, and a brake pedal detecting unit configured to detect brake pedal input information according to the driver's operation of the brake pedal. In addition, the driving information detecting unit 12 can further include a paddle shift and shift lever detecting unit, and a motor speed detecting unit configured to detect the rotational speed of the motor (hereinafter referred to as "motor speed") which is a driving device 41 for driving the electric vehicle.

[0048] Here, the accelerator pedal detecting unit can be a conventional accelerator position sensor (APS) installed on the accelerator pedal and configured to output an electric signal according to the state of the driver's operation of the accelerator pedal. The brake pedal detecting unit can be a conventional brake pedal sensor (BPS) installed on the brake pedal and configured to output an electric signal according to the state of the driver's operation of the brake pedal. In addition, the motor speed detecting unit is a well-known resolver installed in the driving device (driving motor) 41.

[0049] In particular, the driver's driving input information can include an accelerator pedal input value (APS value) detected by the accelerator pedal detecting unit and a brake pedal input value (BPS value) detected by the brake pedal detecting unit. In addition, the driver's driving input information can further include paddle shift input information according to the driver's operation of the paddle shift and shift lever input information (P-, R-, N-, or D- indicated gear information) according to the driver's operation of the shift lever.

[0050] The shift lever input information can be detected by the shift lever detecting unit, and the paddle shift input information can be inputted from the paddle shift into the first controller 20. In addition, the vehicle state information can include the motor speed detected by the motor speed detecting unit. The vehicle running information used by the torque command generating unit 21 to generate the basic torque command can further include the vehicle speed as the vehicle state information. In particular, although not shown in Figure 1 the driving information detecting unit 12, the driving information detecting unit 12 can further include a vehicle speed detecting unit configured to detect the current running speed of the vehicle. The vehicle speed detecting unit can include a wheel speed sensor installed on the driving wheel of the electric vehicle.

[0051] The first controller 20 can include a torque command generation unit 21 configured to generate a basic torque command from vehicle running information, a virtual shift controller 22 configured to generate a compensation torque command (e.g., a virtual shift intervention torque command for realizing a real shift feel) for generating and realizing a real shift feel from the vehicle running information, and a final torque command generation unit 23 configured to generate a final torque command generated by changing the basic torque command using the compensation torque command.

[0052] The basic torque command is a motor torque command determined and generated based on driving information collected while a conventional electric vehicle is running. The torque command generation unit 21 is a vehicle control unit (VCU) or a component thereof in a conventional electric vehicle, which is configured to generate a motor torque command based on driving information. Further, according to the present application, the virtual shift controller 22 can be configured to determine, generate, and output a virtual shift intervention torque command, which is a compensation torque command for realizing a real shift feel, independently of the basic torque command. The virtual shift controller 22 can be added as a component of a vehicle unit or provided as a control component separate from a vehicle controller.

[0053] In the final torque command generation unit 23, the basic torque command input from the torque command generation unit 21 can be changed using the compensation torque command input from the virtual shift controller 22. In other words, the virtual shift intervention torque command as the compensation torque command is added to the basic torque command, thereby obtaining a final torque command. The second controller 30 can be configured to receive the torque command transmitted by the first controller 20, i.e., the final torque command determined by the final torque command generation unit 23 of the first controller 20, and operate the drive device 41 therefrom.

[0054] According to the present application, the drive device 41 is a motor (drive motor) driving an electric vehicle, and the second controller 30 is a well-known motor control unit (MCU) in a conventional electric vehicle, which drives the motor through an inverter and controls the operation of the motor. On the other hand, according to the present application, a virtual shift model is provided and input to the virtual shift controller 22, an input item of the virtual shift model is set to vehicle running information collected in an electric vehicle, and the virtual shift model determines and outputs a virtual shift intervention torque command.

[0055] According to the present application, the input variables of the virtual shift model are the vehicle running information detected by the driving information detection unit 12, which, as described above, includes the driver's driving input information and the vehicle state information. The driver's driving input information here includes the accelerator pedal input information (APS value information), the brake pedal input information (BPS value information), the shift paddle input information, and the shift lever input information (gear position information indicated by P-, R-, N-, and D-). The vehicle state information includes the motor speed.

[0056] In the virtual shift controller 22, the value of an intermediate variable can be calculated from the model input variables using the virtual shift model. Further, a torque instruction for generating and realizing a real shift feeling only, and a limit torque of each virtual gear position reflecting the gear ratio information can be determined from the value of the intermediate variable, and the torque instruction and the limit torque are output. The torque instruction for generating and realizing a real shift feeling only here is not only a virtual shift intervention torque instruction, but also a compensation torque instruction for changing the basic torque instruction.

[0057] Figure 2 The accelerator pedal input information (APS value information), the brake pedal input information (BPS value information), the shift paddle input information, the shift lever input information (gear position information indicated by P-, R-, N-, and D-), and the motor speed (OmegaM) information, which are the vehicle running information, are shown as the input variables of the virtual shift model (M). Further, Figure 2 The intermediate variable for executing the virtual shift function in the virtual shift model (M), that is, the model intermediate variable for generating a real shift feeling obtained by the input variables in the virtual shift model, is shown.

[0058] According to the exemplary embodiment of the present application, the model intermediate variable obtained by the input variables includes a virtual vehicle speed (SpdVir), a downshift virtual vehicle speed (SpdVirDn), a virtual target gear position (TarGe), a target gear position in a virtual manual shift mode (TarGeMan), a virtual current gear position (CurGe), a virtual engine speed (OmegaVir), a gear ratio for the virtual gear position (rG1, rG2, and so on, up to rGi), a virtual longitudinal deceleration gear ratio (rFg), a target input speed based on the virtual target gear position (OmegaTar), a target input speed based on the virtual current gear position (OmegaCur), and a virtual shift progress ratio (xProgress).

[0059] "input speed" here denotes the virtual engine speed which forms the input speed of the virtual transmission when a virtual transmission and a virtual engine are assumed to be present in the electric vehicle. Thus, "target input speed based on virtual target gear" denotes the virtual engine speed for the virtual target gear, and "target input speed based on virtual current gear" denotes the virtual engine speed for the virtual current gear. According to the present application, the intermediate variables for the virtual gearshift are independent of the physical values of the actual hardware of the electric vehicle, but are only used to achieve a real gearshift feeling.

[0060] According to the present application, the actual physical variables which are physically contained in the drive system of the electric vehicle or used as actual measured values include the input variables (APS value, BPS value, shift paddle input value and shift lever input value), the electric motor speed (OmegaM), the virtual gearshift intervention torque (tqltv), and the limit torque (tqLmt) for each virtual gear. Furthermore, according to the exemplary embodiment of the present application, the output variables of the virtual gearshift model (M) include the virtual gearshift intervention torque instruction (compensation torque instruction) (Tqltv) for providing and achieving a real gearshift feeling.

[0061] In addition, the output variables of the virtual gearshift model (M) can also include the limit torque (tqLmt) for each virtual gear. Furthermore, according to the exemplary embodiment of the present application, the output variables of the virtual gearshift model (M) can also include at least one or several of the intermediate variables for the virtual gearshift. For example, the output variables of the virtual gearshift model (M) can also include the virtual target gear (TarGe), the virtual current gear (CurGe) and the virtual engine speed (OmegaVir) of the intermediate variables for the virtual gearshift.

[0062] The virtual target gear (TarGe), the virtual current gear (CurGe) and the virtual engine speed (OmegaVir) output from the virtual gearshift model (M) are transmitted to a cluster controller (not shown) and made a segment of the cluster display information displayed on a cluster device (not shown). The virtual gearshift intervention torque instruction output from the virtual gearshift controller 22 and the limit torque for each virtual gear (for example, the limit torque for the current gear) are input into the final torque instruction generation unit 23 and then used in the final torque instruction generation unit 23 to generate a final torque instruction from the basic torque instruction.

[0063] In other words, in the final torque command generation unit 23, the base torque command is limited to the limit torque for each virtual gear if necessary. When the base torque command is lower than the limit torque value, then the base torque command is used as is. However, when the base torque command is equal to or greater than the limit torque value, then the base torque command can be limited to the limit torque value. In this way, the base torque command limited within the limit torque for each virtual gear in the final torque command generation unit 23 is then added to the virtual shift intervention torque command, and the resulting torque command becomes the final motor torque command.

[0064] When the base torque command is equal to or greater than the limit torque value, the final motor torque command can be determined as the sum of the limit torque value and the virtual shift intervention torque command. In this way, the final motor torque command calculated in the final torque command generation unit 23 can be transmitted to the second controller 30, and the second controller 30 can be configured to operate the motor according to the final motor torque command.

[0065] The intermediate variables used for virtual shifting in the virtual shift model (M) within the virtual shift controller 22 will be described in more detail below. First, a virtual vehicle speed (SpdVir) can be generated as an input to the shift schedule map in the virtual shift model (M) within the virtual shift controller 22. The virtual vehicle speed (SpdVir) can be used as a reference vehicle speed in the virtual shift function. The virtual vehicle speed (SpdVir) can be calculated as a value proportional to the real motor speed (OmegaM) using the real motor speed (OmegaM), which is one of the model input variables, and a virtual longitudinal reduction ratio (rFg).

[0066] In the example of Figure 2 However, according to the exemplary embodiments of the present application, the virtual longitudinal reduction ratio is a preset value. Furthermore, in the virtual shift model, a downshift virtual vehicle speed (SpdVirDn) is generated. The downshift virtual vehicle speed (SpdVirDn) is a variable that is used as an input to the shift schedule map when downshifting. The downshift virtual vehicle speed (SpdVirDn) can be calculated by applying a preset scaling factor and an offset value to the virtual vehicle speed (SpdVir).

[0067] However, when the upshift shift schedule map and the downshift shift schedule map are set separately for use, it is safe to use only the virtual vehicle speed (SpdVir) as the reference speed. When one shift schedule map is set for use without any distinction between the upshift shift schedule map and the downshift shift schedule map, the downshift virtual vehicle speed (SpdVirDn) is used in addition to the virtual vehicle speed (SpdVir) as the reference vehicle speed, to increase the hysteresis effect between upshift and downshift. According to the present application, in order to achieve a normal hysteresis effect, the downshift virtual vehicle speed (SpdVirDn) can be determined to a value that is generated by adding a positive offset value to a value obtained by multiplying the virtual vehicle speed (SpdVir) by a scale factor greater than 1.

[0068] Figure 3A and Figure 3B A shift schedule map for determining a virtual target gear (TarGe) according to the present application is shown. Figure 3A and Figure 3B An upshift shift schedule map and a downshift shift schedule map that are set separately are shown. In each of the shift schedule maps shown, the horizontal axis represents the vehicle speed (km / h), and the vertical axis represents the accelerator pedal input value (APS value). In particular, the vehicle speed of the horizontal axis is the virtual vehicle speed (SpdVir) as the reference vehicle speed. In this way, the input item of the shift schedule map can be set to the accelerator pedal input value (APS value) that indicates the virtual vehicle speed (SpdVir) and the intention of the driver. The virtual vehicle speed (SpdVir) and the virtual target gear (TarGe) corresponding to the accelerator pedal input value (APS value) can be determined by the shift schedule map.

[0069] As shown in Figure 3A and Figure 3B In the case where the upshift shift schedule map and the downshift shift schedule map are set separately from each other, one virtual vehicle speed can be used as the vehicle speed for determining the virtual target gear (TarGe). At this time, as described above, the virtual vehicle speed is the virtual vehicle speed (SpdVir) as the reference vehicle speed, which is obtained by the real motor speed (OmegaM) and the virtual longitudinal deceleration ratio (rFG).

[0070] In this way, when using the upshift shift schedule map and the downshift shift schedule map separately from each other, the virtual target gear (TarGe) can be determined from the virtual vehicle speed (SpdVir) as the reference vehicle speed and in accordance with the accelerator pedal input value (APS value). However, when using one shift schedule map for upshift and downshift, the virtual target gear (TarGe) can be determined using a downshift virtual vehicle speed (SpdVirDn) separate from the virtual vehicle speed (SpdVir) as the reference vehicle speed.

[0071] Figure 4 One shift schedule map according to the present application is shown which can be used for both upshift and downshift. Figure 4 One shift schedule map shown in Fig. 7 can be used both for upshift and for downshift. In particular, for upshift, the virtual vehicle speed (SpdVir) as the reference vehicle speed, which becomes the upshift virtual vehicle speed, is used as an input variable in the shift schedule map for determining the virtual target gear (TarGe). Further, for downshift, the downshift virtual vehicle speed (SpdVirDn) is used as an input variable in the shift schedule map for determining the virtual target gear (TarGe).

[0072] In other words, when using one shift schedule map, for upshift, the virtual target gear (TarGe) can be determined from the virtual vehicle speed (SpdVir) as the reference vehicle speed and in accordance with the accelerator pedal input value (APS value). Further, for downshift, the virtual target gear (TarGe) can be determined in accordance with the downshift virtual vehicle speed (SpdVirDn) and the accelerator pedal input value (APS value). In other words, in the shift schedule map of Fig. 7, for upshift, the vehicle speed of the horizontal axis is the virtual vehicle speed (SpdVir) as the reference speed. Further, for downshift, the vehicle speed of the vertical axis is the downshift virtual vehicle speed (SpdVirDn). Figure 4 In other words, when using one shift schedule map, for upshift, the virtual target gear (TarGe) can be determined from the virtual vehicle speed (SpdVir) as the reference vehicle speed and in accordance with the accelerator pedal input value (APS value). Further, for downshift, the virtual target gear (TarGe) can be determined in accordance with the downshift virtual vehicle speed (SpdVirDn) and the accelerator pedal input value (APS value). In other words, in the shift schedule map of Fig. 7, for upshift, the vehicle speed of the horizontal axis is the virtual vehicle speed (SpdVir) as the reference speed. Further, for downshift, the vehicle speed of the vertical axis is the downshift virtual vehicle speed (SpdVirDn).

[0073] Figure 3A In other words, when using one shift schedule map, for upshift, the virtual target gear (TarGe) can be determined from the virtual vehicle speed (SpdVir) as the reference vehicle speed and in accordance with the accelerator pedal input value (APS value). Further, for downshift, the virtual target gear (TarGe) can be determined in accordance with the downshift virtual vehicle speed (SpdVirDn) and the accelerator pedal input value (APS value). In other words, in the shift schedule map of Fig. 7, for upshift, the vehicle speed of the horizontal axis is the virtual vehicle speed (SpdVir) as the reference speed. Further, for downshift, the vehicle speed of the vertical axis is the downshift virtual vehicle speed (SpdVirDn). Figure 3B In other words, when using one shift schedule map, for upshift, the virtual target gear (TarGe) can be determined from the virtual vehicle speed (SpdVir) as the reference vehicle speed and in accordance with the accelerator pedal input value (APS value). Further, for downshift, the virtual target gear (TarGe) can be determined in accordance with the downshift virtual vehicle speed (SpdVirDn) and the accelerator pedal input value (APS value). In other words, in the shift schedule map of Fig. 7, for upshift, the vehicle speed of the horizontal axis is the virtual vehicle speed (SpdVir) as the reference speed. Further, for downshift, the vehicle speed of the vertical axis is the downshift virtual vehicle speed (SpdVirDn). Figure 4 In other words, when using one shift schedule map, for upshift, the virtual target gear (TarGe) can be determined from the virtual vehicle speed (SpdVir) as the reference vehicle speed and in accordance with the accelerator pedal input value (APS value). Further, for downshift, the virtual target gear (TarGe) can be determined in accordance with the downshift virtual vehicle speed (SpdVirDn) and the accelerator pedal input value (APS value). In other words, in the shift schedule map of Fig. 7, for upshift, the vehicle speed of the horizontal axis is the virtual vehicle speed (SpdVir) as the reference speed. Further, for downshift, the vehicle speed of the vertical axis is the downshift virtual vehicle speed (SpdVirDn).

[0074] When the virtual vehicle speed (SpdVir) as the reference vehicle speed is the upshift virtual vehicle speed, as in the following Equation 1, the downshift virtual vehicle speed (SpdVirDn) is determined as a value that is generated by adding an offset value (β) to a value obtained by multiplying the upshift virtual vehicle speed (SpdVir) by a proportional factor (α).

[0075] Equation 1

[0076] SpdVir = SpdVirDn x α + β

[0077] Next, in the virtual shift model (M) within the virtual shift controller 22, it is determined whether to enter the manual shift mode. When the operation of the shift lever occurs or the input through the shift paddle occurs, the controller can be configured to determine the state of entering the manual shift mode (in the manual shift mode, the shift is made according to the intention of the driver) rather than the state of the usual automatic shift (in the state of the automatic shift, the shift is automatically made according to the preset shift schedule).

[0078] The target gear according to the intention of the driver can be different from the target gear given when the automatic shift is performed. Therefore, in response to the determination of the state of entering the manual shift mode, the target gear in the manual shift mode, that is, the target gear in the virtual manual shift mode (TarGeMan) can be determined in the virtual shift model (M) within the virtual shift controller 22. The target gear in the virtual manual shift mode (TarGeMan) can be determined according to the shift lever input information or the shift paddle input information of the driver.

[0079] In addition, the final target gear in the virtual shift function can be calculated in the virtual shift model (M) within the virtual shift controller 22. As described above, fundamentally, in the automatic shift mode, the target gear determined by the shift schedule map can be determined as the virtual target gear (TarGe). However, in the manual shift mode, the target gear in the virtual manual shift mode (TarGeMan) determined according to the shift lever input or the shift paddle input of the driver can be determined as the virtual target gear (TarGe).

[0080] As described above, the method of determining the target gear by the shift schedule map in the automatic shift mode (not in the manual shift mode) is to use a shift schedule map in which the input items are set to the load values such as the virtual vehicle speed (km / h) and the accelerator pedal input value (APS value) (%). The shift schedule map here is a map in which the input items are set to a plurality of vehicle load value information such as the virtual vehicle speed and the accelerator pedal input value, and in which a virtual target gear corresponding to each combination of the plurality of vehicle load value information is preset. In addition to the accelerator pedal input value (APS value) as the driver's driving input information, the brake pedal input value (BPS value), the basic torque command, and the like are used as the vehicle load value information.

[0081] As described above, the virtual vehicle speed (SpdVir) determined by the virtual longitudinal deceleration transmission ratio (rFg) and the real motor rotational speed (OmegaM) or the downshift virtual vehicle speed (SpdVirDn) determined by the virtual vehicle speed is used as the reference speed which is used as the input item of the shift schedule map. When the target gear is determined as described above, two target gears occur at the current time point, that is, two target gears determined respectively in accordance with the virtual vehicle speed (SpdVir) and in accordance with the downshift virtual vehicle speed (SpdVirDn) as the reference speed.

[0082] In particular, the final target gear can be determined using two values. In this determination method, only when the value of the target gear determined in accordance with the virtual vehicle speed (SpdVir) increases to a value greater than the previous gear (for example, from the first gear to the second gear), such a value is determined as a valid value. Therefore, the target gear determined in accordance with the virtual vehicle speed (SpdVir) can be determined and replaced as the final virtual target gear (TarGe).

[0083] Likewise, only when the value of the target gear determined in accordance with the downshift virtual vehicle speed (SpdVirDn) decreases to a value less than the previous gear (for example, from the second gear to the first gear), such a value is determined as a valid value. Therefore, the target gear determined in accordance with the downshift virtual vehicle speed (SpdVirDn) can be determined and replaced as the final virtual target gear (TarGe). For this, it is necessary to make the virtual target gear (TarGe) be calculated as a value falling within the range from the lowest selectable gear to the highest selectable gear.

[0084] On the other hand, in the virtual shift model (M) within the virtual shift controller 22, a delayed target gear can be determined from the virtual target gear (TarGe) with a value generated by delaying a fixed delay time. The fixed delay time is here a preset time and represents a time during which the gear for the virtual engine speed (OmegaVir) that plans to be changed to the target gear has not yet started. The fixed delay time is a time that represents a state reached before the start of the inertia phase in the real transmission. In the virtual shift model (M) within the virtual shift controller 22, a change in the target gear (TarGe) can be detected to calculate the virtual shift progress ratio (xProgress).

[0085] Here, the change in the target gear represents the determination of a new virtual target gear different from the current gear according to the shift schedule map or the shift paddle input information or the shift lever input information in the manual shift mode. The controller can be configured to start timing from the point in time at which the target gear changes, for example, the point in time at which the new virtual target gear is determined, as time 0. The shift progress ratio (xProgress) can be determined as a percentage of the timing time with respect to a preset total gear time. The shift progress increases to 100%.

[0086] The point in time at which the target gear changes represents the point in time at which the new virtual target gear is determined by the shift schedule map and from the virtual current gear, which is the previous target gear. In this way, the timer starts timing with the point in time at which the target gear changes set as time 0. However, the point in time at which the timing starts can also be replaced by the point in time at which the delay of the target gear change occurs.

[0087] In other words, when the changed virtual target gear is determined, the controller can be configured to start timing from the point in time of the delay time elapsed after the virtual target gear is determined. Then, the controller can be configured to determine the virtual shift progress ratio using the timed time in the same way. Alternatively, as another method, in terms of expression, it is also possible to use a percentage that indicates where the value of the current virtual engine speed (OmegaVir) obtained in real time in the course of performing the shift is located between the target input speed (OmegaCur) based on the virtual current gear, for example, the virtual engine speed for the virtual current gear, and the target input speed (OmegaTar) based on the virtual target gear, for example, the virtual engine speed for the virtual target gear.

[0088] In other words, at the point in time at which the virtual target gear is determined, the virtual shift progress ratio can be determined as a percentage of a speed difference between a target input speed based on the virtual target gear (OmegaTar) and a target input speed based on the virtual current gear (OmegaCur) with respect to a speed difference between a target input speed based on the virtual current gear (OmegaCur) and a virtual engine speed (OmegaVir) generated in the course of performing the shift.

[0089] In the virtual shift model (M) within the virtual shift controller 22, fundamentally, a virtual vehicle speed (SpdVir) as a reference vehicle speed and a virtual gear ratio (rGi) for the virtual current gear can be used to determine a virtual engine speed (OmegaCur). In other words, the virtual engine speed (OmegaCur) can be obtained by a value generated by multiplying the virtual vehicle speed (SpdVir) and the virtual gear ratio (rGi) for the virtual current gear together. Alternatively, the virtual engine speed (OmegaCur) can be obtained by a value generated by multiplying a drive system speed (e.g., motor speed) and the virtual gear ratio (rGi) for the virtual current gear together.

[0090] Further, in the course of performing the shift starting from the point in time at which the target gear is changed (i.e., the point in time at which the shift is started), a virtual engine speed (OmegaVir) can be determined from a target input speed based on the virtual current gear (OmegaCur) (=virtual engine speed for the virtual current gear) and a target input speed based on the virtual target gear (OmegaTar) (=virtual engine speed for the virtual target gear). At this time, the target input speed based on the virtual current gear (OmegaCur) can be obtained using the virtual vehicle speed (SpdVir) at the point in time at which the target gear is changed and the virtual gear ratio (rGi) for the virtual current gear (CurGe).

[0091] The target input speed based on the virtual target gear (OmegaTar) can be obtained using the virtual vehicle speed (SpdVir) at the point in time at which the target gear is changed and the virtual gear ratio (rGi) for the virtual target gear (TarGe). Subsequently, in the course of performing the shift, the virtual engine speed (OmegaVir) obtained can be a value generated by applying a preset change rate limit to the target input speed based on the virtual current gear.

[0092] According to the present application, a current virtual engine speed (OmegaVir) to be reached in the course of performing a shift can be obtained by a virtual vehicle speed in real time, and the current virtual engine speed (OmegaVir) can be determined as a value that varies within a preset rate of change limit (a value for limiting a rate of change) ranging from a virtual speed based on a current gear (a target input speed based on a virtual current gear) to a virtual speed based on a target gear (a target input speed based on a virtual target gear).

[0093] Further, subsequently, as the shift proceeds to a certain extent, the virtual engine speed (OmegaVir) that is set to the target input speed based on the virtual current gear (OmegaCur) (= virtual engine speed for the virtual current gear) is replaced by the target input speed based on the virtual target gear (OmegaTar) (= virtual engine speed for the virtual target gear). As another method, the virtual engine speed (OmegaVir) can be calculated by applying a rate of change limit to a value obtained by multiplying the virtual vehicle speed (SpdVir) that serves as a reference vehicle speed by the virtual gear ratio (rGi) that corresponds to the previously calculated delay target gear.

[0094] On the other hand, in the virtual shift model (M) within the virtual shift controller 22, fundamentally, the virtual current gear (CurGe) indicates a current gear at a previous time, that is, a current gear that functions until the shift completion condition is satisfied before the shift is started. In other words, the value of the current gear can be maintained until the shift completion condition is satisfied. The virtual target gear determined according to the shift schedule map can be maintained as a target gear that is achieved after the shift is completed.

[0095] However, when the shift completion condition is satisfied after the shift is started, the virtual current gear (CurGe) that functions until the condition is satisfied is replaced by the virtual target gear (TarGe). From the point in time at which the shift completion condition is satisfied, the previous target gear becomes the current gear.

[0096] At this time, the shift completion condition can include one or more of the following conditions:

[0097] 1) a condition that the value of the virtual shift progress ratio (xProgress) is 100%;

[0098] 2) a condition that the value of the virtual shift progress ratio (xProgress) is reset to 0%;

[0099] 3) a condition that the value of the virtual shift progress ratio (xProgress) is equal to or greater than a fixed value;

[0100] 4) the condition that the difference between the virtual engine speed (OmegaVir) and the virtual engine speed (OmegaTar) for the virtual target gear (i.e. the target input speed based on the virtual target gear) is equal to or less than a fixed value; and

[0101] 5) the condition that the value obtained by multiplying the virtual vehicle speed (SpdVir) (which is the reference vehicle speed) by the virtual gear ratio (rGi) (which corresponds to the delayed target gear) is the same as the virtual engine speed (OmegaVir) obtained by using the rate of change limit value for the value obtained by said multiplication, or the difference between the value obtained by said multiplication and the virtual engine speed (OmegaVir) is equal to or less than a fixed value.

[0102] At this time, as to the "condition for resetting the value of the virtual shift progress ratio (xProgress) to 0%", in the case where the control logic is configured in such a manner that the virtual shift progress ratio reaches 100% and then is immediately reset to 0%, as described above, it is determined that the time point at which the reset to 0% is performed is the time point at which the shift is completed. In other words, the shift progress ratio is kept at 0% until after the shift event is started again. However, it is possible to determine that the time point at which the shift progress ratio first reaches 0% itself is the time point at which the shift is completed.

[0103] As described above, the completion of the shift can be determined based on the virtual shift progress ratio (xProgress) and can be determined based on the virtual engine speed. When the virtual engine speed converges to the virtual engine speed for the virtual target gear such that the difference between these two is equal to or less than a fixed value, it can also be determined that the shift completion condition is satisfied.

[0104] Next, in a vehicle equipped with a real transmission, each time an upshift is performed, the gear ratio decreases. Therefore, the torque multiplication effect between the front gears and the rear gears in the transmission decreases. Therefore, eventually, even if the engine produces the same torque, the acceleration eventually obtained decreases. In order to simulate this effect, according to the present application, the limit torque (tqLmt) for each virtual gear can be calculated and used to limit the torque command.

[0105] At this time, in the virtual shift model (M) within the virtual shift controller 22, the limit torque (tqLmt) for each virtual gear (the limit torque for the current gear) can be calculated by multiplying the virtual gear ratio (rGi) (which corresponds to the virtual current gear (CurGe)), the virtual longitudinal deceleration gear ratio (rFg), and the limit torque setting parameter. Furthermore, the limit torque (tqLmt) for each virtual gear is set in both directions, i.e. in the drive direction of the motor and in the regenerative power generation direction. This is achieved by using two limit torque setting parameters.

[0106] In order to apply the limit torque and thereby control the motor torque, the motor torque in the drive direction can be limited to the value of the limit torque (tqLmt) for the drive direction, and the motor torque in the regenerative power generation direction can be limited to the value of the limit torque (tqLmt) for the regenerative power generation direction.

[0107] There is another method. Three types of motor torque instructions, i.e., a regenerative power generation motor torque instruction, an inertia coasting motor torque instruction, and a drive motor torque instruction, are generated and added together, thereby generating a basic torque instruction. Then, during running, the torque instruction is limited to the value of the limit torque (tqLmt) for the drive direction. During inertia coasting and during regenerative power generation, the torque instruction is limited to the value of the limit torque (tqLmt) for the regenerative power generation direction. Of course, the values of the regenerative power generation torque instruction and the inertia coasting torque instruction can be 0 during driving, and the value of the drive torque instruction can be 0 during regenerative power generation or inertia coasting.

[0108] Furthermore, in order to not only limit the maximum value of the torque, but also to simulate the effect of the transmission ratio applied in proportion, when determining the value between the accelerator pedal input value (APS value) and the drive torque, the application ratio of the accelerator pedal input value with respect to the value of the limit torque (tqLmt) for the drive direction is used, instead of the application ratio of the accelerator pedal input value (APS value) with respect to the maximum motor torque.

[0109] Furthermore, in addition to the method of determining the torque instruction using the simple ratio of the limit torque (tqLmt) for each virtual gear position to the accelerator pedal input value (APS value), a torque ratio that is a function of the preset accelerator pedal input value of the limit torque (tqLmt) can be used to determine the torque instruction. For example, when the accelerator pedal input value (i.e., the APS value) is 20%, 50%, and 80%, respectively, the torque of the basic torque instruction can be determined to be 20%, 50%, and 80% of the limit torque (tqLmt), respectively. However, if the torque ratio values mapped to the APS values are 40%, 70%, and 85%, respectively, when the APS values are 20%, 50%, and 80%, respectively, the torque of the basic torque instruction can be determined to be 40%, 70%, and 85% of the limit torque (tqLmt), respectively.

[0110] Figure 5 A graph showing the maximum motor torque characteristic curve according to the motor rotational speed and the limit torque of each virtual gear position (gear positions 1, 2, 3, 4, 5, etc.) according to the present application is shown. Figure 5 It is shown that the higher the motor rotational speed, the higher the gear position (gear), and the higher the gear position, the lower the maximum motor torque. Furthermore, Figure 5It is shown that the higher the gear is, the lower the transmission ratio is, and the final wheel transmission torque is reduced in the high gear compared to the low gear. The maximum motor torque characteristic curve is a curve showing a preset maximum allowable torque for each motor speed. The limit torque of each virtual gear can be calculated to reflect the transmission ratio information of each gear.

[0111] Figure 5 Examples in which the limit torque of each virtual gear is determined are shown. As described above, the limit torque of each virtual gear (the limit torque for the current gear) can be calculated as a value obtained by multiplying the virtual transmission ratio (rGi) corresponding to the virtual current gear (CurGe), the virtual longitudinal deceleration transmission ratio (rFg), and the limit torque setting parameter.

[0112] This means that the magnitude of the limit torque of each virtual gear can be set according to the limit torque setting parameter value. Figure 5 It is shown that the limit torque of each virtual gear can be adjusted to have a value above or below the maximum motor torque characteristic curve. As such an example, as shown in Figure 5 , the limit torque of each virtual gear can be set to have a value greater than the corresponding maximum motor torque on the maximum motor torque characteristic curve. In particular, the maximum performance of the motor can be achieved.

[0113] Alternatively, the curve of the limit torque of the virtual gear can be drawn in such a way as to intersect the maximum motor torque characteristic curve. The value of the limit torque of each virtual gear can be set to be greater than the corresponding value on the maximum motor torque characteristic curve in one or several intervals of motor speed, and for this the value of the limit torque is set to be equal to or less than the corresponding value on the maximum motor torque characteristic curve in other intervals of motor speed. Thus, for each virtual gear, the maximum performance of the motor can be achieved in one or several intervals of motor speed, and the effect of different transmission ratios between gears can also be achieved in one or several intervals of motor speed.

[0114] Furthermore, the value of the limit torque of each virtual gear can be set to be less than the corresponding value on the maximum motor torque characteristic curve in all intervals of motor speed. In particular, the maximum performance of the motor is not possible, but the effect of different transmission ratios between gears can be maximized. On the other hand, the final torque command generation unit 23 of the first controller 20 can be configured to receive the basic torque command generated by the addition of the motor torque commands from the torque command generation unit 21, and the virtual shift intervention torque command from the virtual shift controller 22.

[0115] Further, the final torque command generation unit 23 can be configured to use the virtual shift intervention torque command generated in the virtual shift controller 22 to correct the basic torque command generated in the torque command generation unit 21. At this time, the final torque command generation unit 23 can be configured to additionally add the virtual shift intervention torque command, which is a compensation torque command for generating a real shift feeling, to the basic torque command, which is generated by adding the motor torque command, thereby generating the final torque command.

[0116] Figure 6 A graph showing an example of a virtual shift intervention torque characteristic curve according to the present application. Thus, the second controller 30 can be configured to receive the final torque command generated and output by the final torque command generation unit 23 of the first controller 20, and then operate the inverter according to the received final torque command, thereby operating the drive device 41. As a result, the vehicle urging phenomenon that occurs according to the shift effect when a virtual shift is performed is realized in a similar manner to when a shift is performed in a real transmission.

[0117] In the virtual shift model (M) within the virtual shift controller 22, the virtual shift intervention torque (tqItv) is set in the form of a torque characteristic curve in which a virtual shift progress ratio (xProgress) is set as an argument. Alternatively, the virtual shift intervention torque (tqItv) can be provided by mapping a model based on the following physical values: a virtual engine speed (OmegaVir), a target input speed (OmegaCur) based on a virtual current gear (i.e., a virtual engine speed for a virtual current gear), and a target input speed (OmegaTar) based on a virtual target gear (i.e., a virtual engine speed for a virtual target gear).

[0118] Further, in calculating the virtual shift intervention torque command, the shape of the virtual shift intervention torque should be different according to the type of the transmission and the shift classification. The type of the transmission includes an automatic transmission (AT), a dual clutch transmission (DCT), an automated manual transmission (AMT), and the like. Further, the shift classification includes a power-on upshift, a power-off upshift (lift-foot-up), a power-on downshift (kick-down), a power-off downshift, and a near-stop downshift.

[0119] To calculate the virtual shift intervention torque command, the virtual shift controller 22 can be configured to determine a current shift classification. In this determination method, when a virtual target gear (TarGe) is higher than a virtual current gear (CurGe) (i.e., virtual target gear > virtual current gear), it is an upshift case. Conversely, when a virtual target gear (TarGe) is lower than a virtual current gear (CurGe) (i.e., virtual current gear > virtual target gear), it is a downshift case.

[0120] Further, when the basic torque command is greater than a preset reference torque value, it is a power-on case. Conversely, when the basic torque command is less than the preset reference torque value, it is a power-off case. As a result, according to the present application, when a current shift classification is determined based on a virtual current gear, a virtual target gear, etc., a virtual shift intervention torque characteristic curve corresponding to the current shift classification is selected from among virtual shift intervention torque characteristic curves for shift classifications. A virtual shift intervention torque for generating a real shift feeling can be determined in real time according to the selected virtual shift intervention torque characteristic curve.

[0121] At this time, a value of the virtual shift intervention torque corresponding to a current virtual shift progress ratio can be determined according to the selected virtual shift intervention torque characteristic. The virtual shift intervention torque characteristic is information preset for each shift classification to be added to a virtual shift model (M) within the virtual shift controller 22. The virtual shift intervention torque characteristic can be preset to vary according to the type of the transmission and the shift classification.

[0122] The magnitude of the virtual shift intervention torque can be set to be adjusted by using one or more combinations of the virtual engine speed (OmegaVir), the accelerator pedal input value (APS value), the real motor torque (i.e., the basic torque command of the motor generated in the torque command generation unit 23), and one or both of the virtual current gear (CurGe) and the virtual target gear (TarGe) as torque magnitude setting variables.

[0123] Generally, it is natural that the greater the magnitude of the motor torque (i.e., the basic torque command), the greater the magnitude of the virtual shift intervention torque should be; this is because the higher the gear, the lower the ratio between gears, so the magnitude of the virtual shift intervention torque should be decreased; and because the higher the virtual engine speed, the higher the degree of speed reduction and increase when performing a shift, so the magnitude of the virtual shift intervention torque should also be increased. On the other hand, as described above, according to the present application, the enhancement is defined as instantaneously generating a motor torque greater than the maximum permissible torque, which is determined with the normal state as a reference.

[0124] According to the present application, the final motor torque command determined in the final torque command generation unit 23 of the first controller 20 can be changed to a value greater than the maximum allowable torque for a short time (i.e., instantaneously and temporarily), and then can return to the initial state. In this way, motor enhancement is achieved.

[0125] The travel control method of the electric vehicle according to the present application can include: generating a motor torque command using a basic torque command and a virtual shift intervention torque for generating a real shift feeling while the electric vehicle is driven; and operating a motor for driving the electric vehicle according to the generated motor torque command, thereby generating the real shift feeling; wherein, in generating the real shift feeling, an enhancement control (which controls the operation of the motor) is executed so that a motor torque exceeding an allowable torque of the motor is generated for at least a part of the time in the process of generating the real shift feeling, thereby executing the generation of the real shift feeling and the enhancement control in conjunction with each other.

[0126] At this time, the at least a part of the time in the process of generating the real shift feeling can be an interval simulating an inertia phase in a virtual shift process. According to the present application, the method of generating a virtual shift feeling in conjunction with instantaneous enhancement is roughly divided into two methods:

[0127] 1) implementing an excess portion of the maximum output torque of the virtual gear,

[0128] 2) implementing a torque phase characteristic of the virtual shift intervention torque and implementing a push or resistance feeling in the inertia phase at the time of acceleration.

[0129] Figure 7 A flowchart showing a method of implementing enhancement and a real shift feeling in conjunction according to the present application is shown. First, the implementation of an excess portion of the maximum output torque of the virtual gear will be described. In a vehicle equipped with a real transmission, upshift from a low gear to a high gear makes the transmission ratio decrease. Therefore, the torque multiplication effect between the front gear and the rear gear in the transmission is reduced. For this reason, even if the engine generates the same torque, the final acceleration obtained is reduced. In implementing the virtual shift function, the torque multiplication effect should be simulated. In order to implement the virtual shift function, the limit torque of each virtual gear is calculated and used.

[0130] As described above with reference to Figure 5As described, the limit torque of each virtual gear is used by executing the "encompassing type" technique, the "intersecting type" technique, or the "truncated type" technique. In the "encompassing type" technique, the limit torque used for each virtual gear is higher than the corresponding limit torque on the maximum motor torque characteristic curve. In the "intersecting type" technique, the limit torque used for each virtual gear is equal to the corresponding limit torque on the maximum motor torque characteristic curve. In the "truncated type" technique, the limit torque used for each virtual gear is lower than the corresponding limit torque on the maximum motor torque characteristic curve.

[0131] The maximum motor torque characteristic curve is here shown as a curve of the maximum permissible torque preset for each motor speed using the normal state as a reference, and is the maximum torque characteristic curve generated when no enhancement is executed. According to the present application, in order to execute effective enhancement using virtual gears, it is preferable to set the limit torque of each virtual gear to the torque on the maximum motor torque characteristic curve.

[0132] In other words, according to the present application, in order to execute enhancement control, among the above-described techniques of calculating the limit torque of each virtual gear, the "intersecting type" technique in which the limit torque of each virtual gear is plotted so as to intersect the maximum motor torque characteristic curve can be applied. In the intersecting type technique, the value of the limit torque of each virtual gear is set to be greater than the corresponding value on the maximum motor torque characteristic curve in one or several intervals of motor speed, and for this the value of the limit torque is set to be equal to or less than the corresponding value on the maximum motor torque characteristic curve in other intervals of motor speed.

[0133] Figure 8 A diagram showing the excess and deficiency of the limit torque of each virtual gear according to an exemplary embodiment of the present application, which are generated by comparison with the maximum motor torque characteristic curve varying with motor speed when the "intersecting type" technique is applied. As shown, in order to control, a torque excess interval in which the limit torque of each virtual gear exceeds the maximum motor torque corresponding to the current motor speed is set to an interval in which enhancement is executed. Further, in order to control, a torque deficiency interval in which the limit torque of each virtual gear is less than the maximum motor torque corresponding to the current motor speed is set to an interval in which enhancement is not executed but the load is adjusted. Thus, the enhancement is turned on and off in conjunction with a real gear shift feeling.

[0134] At this time, the ratio of the torque excess portion in the enhanced excess region and the torque deficiency portion in the non-enhanced deficiency region is adjusted according to the specifications of the electric motor. Based on the "intersection type" technique, it can be determined whether to set the limit torque of each virtual gear as described above in a similar manner to when the "encompassing type" technique is applied or in a similar manner to when the "truncation type" technique is applied. This can be applied not only to the torque in the acceleration direction (electric motor discharge direction and drive direction) but also to the torque in the deceleration direction (electric motor charge direction and regenerative power generation direction).

[0135] Furthermore, the limit torque of each virtual gear, and thus the ratio of the torque excess portion and the torque deficiency portion, can be adjusted according to the state of the PE component (i.e., the current temperature of the PE component such as the electric motor), the temperature of the coolant, and the like. For example, the magnitude of the limit torque of each virtual gear is set in a manner that the torque excess portion and the torque deficiency portion alternately appear in a repetitive manner according to the electric motor rotational speed, fundamentally applying the "intersection type" technique. However, when the enhancement is limited to be performed due to high temperature, the magnitude of the limit torque is relatively set in a similar manner to when the "truncation type" technique is performed. In contrast, when the temperature is low and cooling is easily performed, the magnitude of the limit torque is set in a similar manner to when the "encompassing type" technique is performed.

[0136] As described above, the limit torque (tqLmt) of each virtual gear can be calculated by multiplying the virtual transmission ratio (rGi) corresponding to the virtual current gear (CurGe), the virtual longitudinal deceleration transmission ratio (rFg), and the limit torque setting parameter. As described above, the adjustment of the limit torque setting parameter enables the adjustment of the limit torque of each virtual gear. Next, the implementation of the torque phase characteristics of the virtual shift intervention torque, and the implementation of the push-back feeling or the retardation feeling in the inertia phase at the time of acceleration will be described.

[0137] Figure 9 A reference graph showing the change in vehicle acceleration over time when a shift is performed in a vehicle equipped with a real transmission is shown. Figure 10 A graph showing the state of the virtual shift intervention torque applied at the time of acceleration according to the present application for implementing a real shift feeling, i.e., for simulating the change in vehicle acceleration as shown in Figure 9 in a vehicle equipped with a real transmission, the output torque of the transmission changes due to the interaction of the friction elements and the change in the input torque of the transmission at the time of performing a shift. This change occurs in the torque phase and the inertia phase at the time of performing a shift.

[0138] Furthermore, in the inertia phase, when a shift is performed, the following occurs: due to the speed change in the transmission under the inertia of the previous gear, an additional acceleration / deceleration torque is applied in the transmission toward the next gear, which is different from the input torque. When an upshift is performed in a vehicle equipped with a real transmission, if the inertia of the previous gear in the transmission is such that it decelerates, a torque in the acceleration direction is applied toward the output shaft. This application is called a push-through feeling. Conversely, when a downshift is performed, if the inertia of the previous gear in the transmission is such that it accelerates, a torque in the deceleration direction is applied toward the output shaft. This application is called a drag feeling.

[0139] Figure 10 An example of the enhanced opening / closing control for simulating the vehicle acceleration when a shift is performed in an electric vehicle implementing a real shift feeling according to the present application is shown, and an example in which the torque overshoot is enhanced to produce a push-through feeling is shown. In Figure 10 , the dashed line represents the maximum permissible torque (which is determined with the normal state as a reference) produced when the enhancement is not performed. The torque overshoot represents the torque magnitude by which the electric motor torque represented by the solid line exceeds the corresponding maximum permissible torque represented by the dashed line.

[0140] Furthermore, the torque undershoot represents the torque magnitude by which the electric motor torque represented by the solid line falls below the corresponding maximum permissible torque represented by the dashed line. In Figure 10 , the solid line represents the electric motor torque according to the present application, which is used to simulate the acceleration when a shift is performed in an electric vehicle equipped with a transmission as shown in Figure 9 . The electric motor torque represented by the solid line is a virtual shift intervention torque (compensation torque) for implementing a real shift feeling.

[0141] Furthermore, the torque represented by the solid line in Figure 10 can be a torque command, and according to the present application, it is a virtual shift intervention torque command for performing the enhancement and the real shift feeling in conjunction. Specifically, the torque represented by the solid line in Figure 10 is a torque command output by the virtual shift controller 22 of the first controller 20 among the constituent elements of Figure 1 . According to the present application, when the second controller 30 operates the electric motor according to the final torque command generated in the first controller 20, the state of the vehicle acceleration as shown in Figure 9 is evoked.

[0142] According to the present application, when a real shift feeling is implemented, it is also possible to simulate the torque change as described above. Therefore, a method of opening and closing the enhancement in conjunction with the torque change is proposed. With this method, it is possible to apply the strategy of performing the enhancement bidirectionally in the direction of exceeding the maximum permissible charge torque and the maximum permissible discharge torque (to simulate a real shift feeling).

[0143] Figure 10 It is indicated that the enhanced non-execution interval (enhanced-off interval) and the enhanced execution interval (enhanced-on interval) are repeatedly alternated, in the enhanced non-execution interval, the motor torque is reduced to be lower than the existing maximum allowable torque determined with the normal state as a reference, in the enhanced execution interval, the motor torque is increased to exceed the existing maximum allowable torque. In Figure 10 In the enhanced non-execution interval, the torque deficiency portion is a torque magnitude in which the motor torque (torque command) drops below the maximum allowable torque when a real shift feeling is generated. Therefore, in the virtual shift process, the space for the motor torque command is as large as the torque deficiency portion. The motor torque command has a value smaller than the maximum allowable torque at this time. This contributes to cooling of the PE components, such as the motor.

[0144] On the other hand, in the enhanced execution interval, the torque excess portion is a torque magnitude in which the motor torque (torque command) exceeds the maximum allowable torque. The motor torque command is generated so as to temporarily exceed the maximum allowable torque when a real shift feeling is generated in the virtual shift process. Therefore, in the process of realizing the virtual shift feeling, the motor torque that exceeds the maximum allowable torque can be output. Therefore, it is possible to realize a push feeling while executing motor enhancement.

[0145] Figure 11 And Figure 12 Each shows a graph that illustrates an example of adjusting the push feeling magnitude when a real shift feeling is generated according to the present application. Figure 11 And Figure 12 Each shows a motor torque characteristic curve (a curve for a virtual shift intervention torque command) that shows a virtual shift intervention torque when an upshift is executed. In Figure 11 And Figure 12 In the enhanced non-execution interval, the torque deficiency portion is a torque magnitude in which the motor torque (torque command) drops below the maximum allowable torque when a real shift feeling is generated. Therefore, in the virtual shift process, the space for the motor torque command is as large as the torque deficiency portion. The motor torque command has a value smaller than the maximum allowable torque at this time. This contributes to cooling of the PE components, such as the motor.

[0146] When a downshift is executed, a motor torque characteristic curve (e.g., a curve for a virtual shift intervention torque command) is obtained by inverting the illustrated motor torque characteristic curve generated when an upshift is executed upside down. At this time, the maximum allowable torque characteristic curve becomes a maximum allowable charge torque characteristic curve. With respect to the virtual shift intervention torque, when a downshift is executed, a retardation feeling can be realized by a torque excess portion that exceeds the maximum allowable charge torque.

[0147] In other words, when an upshift is executed, a push feeling of the inertia phase can be realized by a torque excess portion that exceeds the maximum allowable discharge torque. However, when a downshift is executed, a retardation feeling of the inertia phase can be realized by a torque excess portion that exceeds the maximum allowable charge torque (e.g., an excess portion that exceeds the absolute value of the charge torque).

[0148] Further, according to the present application, the characteristic of the virtual shift intervention torque can be adjusted in accordance with the operating state of the PE component (i.e., the current temperature of the PE component (e.g., the electric motor)), the temperature of the coolant for cooling the PE component (e.g., the electric motor), and the like. Thus, the ratio of the torque excess portion to the torque deficiency portion can be adjusted. For example, when the temperature is low and cooling is easily performed, as in the example of Figure 11 , the magnitude of the push or resistance feeling can be set to an increased magnitude. Further, when the enhancement is limited due to high temperature, as in the example of Figure 12 , the magnitude of the push or resistance feeling can be set to a decrease. Further, in addition to the method of adjusting the magnitude of the push or resistance feeling, the ratio of the limit torque excess portion to the limit torque deficiency portion is adjusted by a method of adjusting the duration of the push or resistance feeling (the maintenance time of the torque excess portion), a method of adjusting the offset amount of the virtual shift intervention torque characteristic curve, and the like.

[0149] Referring to Figure 7 , when the virtual shift function is on, the electric motor enhancement function can also be on. When the virtual shift function is on and the enhancement is on, the controller can be configured to determine whether the enhancement is additionally performed or whether the enhancement is limited. Further, when the enhancement can be additionally performed, the enhancement on interval and the torque excess portion are increased, as in Figure 11 . Further, when the enhancement is limited, the enhancement on interval and the torque excess portion are relatively decreased, as in Figure 12 .

[0150] The embodiments of the present application are described in detail above, but this does not limit the scope of the claimed present application. Various modifications and improvements of the present application by those of ordinary skill in the art using the basic concept of the present application defined by the appended claims are also included in the scope of the claimed present application.

Claims

1. A travel control method of an electric vehicle, comprising: generating, by a controller, an electric motor torque command using a basic torque command and a virtual shift intervention torque for generating a real shift feeling while the electric vehicle is traveling; operating, by the controller, an electric motor for driving the electric vehicle in accordance with the generated electric motor torque command, and generating a real shift feeling, wherein at least a part of a period during which the real shift feeling is generated, an enhanced control of operating the electric motor is executed so that an electric motor torque exceeding a permissible torque of the electric motor is generated, whereby the generation of the real shift feeling and the enhanced control are executed in conjunction.

2. The travel control method of an electric vehicle according to claim 1, wherein At least a part of the period during which the real shift feeling is generated is an interval during which an inertia phase in a virtual shift process is simulated.

3. The travel control method of the electric vehicle according to claim 1, wherein When the real shift feeling is generated, when a virtual upshift is executed, the electric motor is operated with an electric motor torque command generated by using a virtual shift intervention torque that is larger than a maximum allowable discharge torque of the electric motor, whereby a push feeling of the electric vehicle is realized.

4. The travel control method of the electric vehicle according to claim 1, wherein When the real shift feeling is generated, when a virtual downshift is executed, the electric motor is operated with an electric motor torque command generated by using a virtual shift intervention torque that is larger than a maximum allowable charge torque of the electric motor, whereby a drag feeling of the electric vehicle is realized.

5. The travel control method of the electric vehicle according to claim 1, wherein When the real shift feeling is generated, the controller is configured to: execute an enhanced opening control using a virtual shift intervention torque that is higher than a maximum permissible torque of the electric motor and execute an enhanced closing control using a virtual shift intervention torque that is lower than the maximum permissible torque of the electric motor, and during a remaining part of the at least a part of the period during which the real shift feeling is generated, use a virtual shift intervention torque that is lower than the maximum permissible torque of the electric motor.

6. The travel control method of an electric vehicle according to claim 5, wherein When the real shift feeling is generated, the controller is configured to adjust a ratio of a torque excess part to a torque deficiency part in accordance with an operating state of a powertrain electronic component, the torque excess part being a torque excess part in which the virtual shift intervention torque exceeds the maximum permissible torque of the electric motor, the torque deficiency part being a torque deficiency part in which the virtual shift intervention torque is lower than the maximum permissible torque of the electric motor.

7. The travel control method of the electric vehicle according to claim 6, wherein The operating state of the powertrain electronic component is indicated by a temperature of the electric motor or a temperature of a coolant that cools the electric motor.

8. The travel control method of the electric vehicle according to claim 5, wherein When the real shift feeling is generated, the controller is configured to adjust a magnitude of the torque excess part or a maintenance time of the torque excess part in accordance with an operating state of a powertrain electronic component, the torque excess part being a torque excess part in which the virtual shift intervention torque exceeds the maximum permissible torque.

9. The travel control method of the electric vehicle according to claim 8, wherein The operating state of the powertrain electronic component is indicated by a temperature of the electric motor or a temperature of a coolant that cools the electric motor.

10. The travel control method of the electric vehicle according to claim 1, wherein The enhanced control includes operating the electric motor using an electric motor torque command generated by the basic torque command, the basic torque command being defined as a limit torque having a value higher than a torque value on a maximum electric motor torque characteristic curve, the limit torque being set to define the basic torque command.

11. The travel control method of an electric vehicle according to claim 10, wherein The value of the limit torque of each virtual gear position is set to be greater than the corresponding value on the maximum motor torque characteristic curve in a partial range of the motor rotational speed, and the value of the limit torque of each virtual gear position is set to be equal to or less than the corresponding value on the maximum motor torque characteristic curve in the remaining range of the motor rotational speed different from the partial range of the motor rotational speed. The value of the limit torque of each virtual gear position is set to be greater than the corresponding value on the maximum motor torque characteristic curve in a partial range of the motor rotational speed, and the value of the limit torque of each virtual gear position is set to be equal to or less than the corresponding value on the maximum motor torque characteristic curve in the remaining range of the motor rotational speed different from the partial range of the motor rotational speed.

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