阅读说明：本技术 电动车辆的行驶控制方法 (Method for controlling running of electric vehicle ) 是由 吴智源 鱼祯秀 于 2020-11-26 设计创作，主要内容包括：本发明提供一种电动车辆的行驶控制方法。所述方法包括在电动车辆行驶时,使用基本扭矩指令和用于产生真实换挡感觉的虚拟换挡干预扭矩来产生电动机扭矩指令。根据所产生的电动机扭矩指令来使得用于驱动电动车辆的电动机运行以产生真实换挡感觉。在产生真实换挡感觉时,在产生真实换挡感觉的至少一部分时间的过程中,执行对电动机运行的增强控制从而使得产生超过电动机的许可扭矩的电动机扭矩,从而联同地执行真实换挡感觉的产生和增强控制。(The invention provides a running control method for an electric vehicle. The method includes generating a motor torque command while the electric vehicle is in motion using a base torque command and a virtual shift intervention torque for generating a real shift feel. A motor for driving the electric vehicle is operated according to the generated motor torque command to produce a real gear change feeling. In generating the real shift feel, the intensifying control of the operation of the electric motor is performed so that the electric motor torque exceeding the allowable torque of the electric motor is generated during at least a part of the time when the real shift feel is generated, thereby performing the generating and intensifying control of the real shift feel in conjunction.)

1. A running control method of an electric vehicle, comprising:

generating, by the controller, a motor torque command using the base torque command and a virtual shift intervention torque for generating a real shift feel while the electric vehicle is running;

operating, by a controller, a motor for driving the electric vehicle according to the generated motor torque command, and generating a real gear change feeling,

wherein the enhancing control of the motor operation is executed so that the motor torque exceeding the allowable torque of the motor is generated during at least a part of the period during which the real shift feeling is generated, thereby executing the generation of the real shift feeling and the enhancing control in conjunction.

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

3. The running control method of an electric vehicle according to claim 1, wherein the boost control is an operation of the electric motor with a motor torque command generated by using a virtual shift intervention torque that is higher than a maximum allowable torque.

4. The running control method of an electric vehicle according to claim 3, wherein in generating a real shift feel, when a virtual upshift is performed, the electric motor is operated with a motor torque command generated by using a virtual shift intervention torque that is larger than a maximum allowable discharge torque of the electric motor, thereby achieving a thrust feel of the electric vehicle.

5. The running control method of an electric vehicle according to claim 3, wherein in generating the real shift feeling, when the virtual downshift is performed, the electric motor is operated with a motor torque command generated by using a virtual shift intervention torque larger than a maximum allowable charging torque of the electric motor, thereby realizing a feeling of retardation of the electric vehicle.

6. The running control method of an electric vehicle according to claim 3, wherein, when a real shift feeling is generated, the controller is configured to:

executing an intensified on-control using a virtual shift intervention torque higher than a maximum allowable torque of the electric motor and executing an intensified off-control by using a virtual shift intervention torque lower than the maximum allowable torque of the electric motor,

and using a virtual shift intervention torque that is lower than a maximum allowable torque of the electric motor during a remaining portion that is not the at least a portion of the time to produce the real shift feel.

7. The running control method of an electric vehicle according to claim 6, wherein, in generating the real shift feel, the controller is configured to adjust a ratio of a torque excess portion, which is a torque excess portion where the virtual shift intervention torque exceeds a maximum allowable torque of the electric motor, to a torque deficiency portion, which is a torque deficiency portion where the virtual shift intervention torque is lower than the maximum allowable torque of the electric motor, in accordance with an operation state of a powertrain electronic component.

8. The running control method of an electric vehicle according to claim 7, wherein the operation 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.

9. The running control method of an electric vehicle according to claim 6, wherein, in generating a real shift feel, the controller is configured to adjust a magnitude of a torque excess portion or a maintenance time of the torque excess portion, which is the torque excess portion where the virtual shift intervention torque exceeds the maximum allowable torque, in accordance with an operation state of a powertrain electronic component.

10. The running control method of an electric vehicle according to claim 9, wherein the operation 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.

11. The running control method of an electric vehicle according to claim 1, wherein the boost control includes, with respect to a limit torque of each virtual gear: the motor is operated using a motor torque command generated by the base torque command defined as a limit torque having a value higher than a torque value on a maximum motor torque characteristic curve, the limit torque being set to define the base torque command.

12. The running control method of an electric vehicle according to claim 11, wherein 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 the motor rotation speed, and the value of the limit torque of each virtual gear is set to be equal to or less than the corresponding value on the maximum motor torque characteristic curve in the remaining intervals of the motor rotation speed different from the one or several intervals.

Technical Field

The present invention relates to a travel control method of an electric vehicle, and more particularly, to an enhanced application control strategy capable of improving both drivability and acceleration performance of an electric vehicle, and a travel control method of an electric vehicle using the enhanced application control strategy.

Background

Electric Vehicles (EVs) are known that use one or more electric motors for propulsion. A drive system of an electric vehicle includes: an electric motor serving as a driving force source; a battery for supplying electric power to the motor; an inverter for driving the motor; and a decelerator that reduces the rotational power of the motor and transmits the reduced rotational power to the driving wheels. The motor is connected to the battery via an inverter, so that the battery is charged or discharged according to an operation mode of the motor.

During a driving operation of the motor, the inverter converts a Direct Current (DC) current into an Alternating Current (AC) current and supplies the resulting alternating current to the motor through a cable. In contrast, during a regenerative power generation operation of the motor, the inverter converts alternating current generated by the motor (which operates as a generator) into direct current and supplies the resulting direct current to the battery to charge the battery.

Unlike internal combustion engine vehicles, electric vehicles do not use a multi-speed transmission. Instead, electric vehicles use a retarder, which is arranged between the electric motor and the driving wheels and uses a fixed transmission ratio. The reason for this is as follows. The internal combustion engine has a wide energy efficiency distribution range according to an operating point and provides high torque only at high speeds. In contrast, the motor has a relatively narrow energy efficiency distribution range according to an operating point, and can provide high torque even at low speed using only its own characteristics.

On the other hand, the acceleration performance of the electric vehicle depends on the torque capacity of the motor. The torque capacity of the motor is affected by the performance of the inverter that controls the motor, the power supply capacity of the battery, and the maximum capacity of the power transmission electronics (PE) components, among other things. Generally, the maximum capacity is defined so that it is used within a range in which safety is ensured, and the limit value is adjusted to maintain thermodynamic equilibrium in a normal state. Therefore, when the load is at or above the limit value, a torque higher than the rated torque may be generated, and thus acceleration may be increased. However, especially the PE components involved may overheat, leading to vehicle fires.

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

However, if the boost is performed to the maximum extent while the electric vehicle is running, it is necessary to alternately perform the boost operation and the normal operation. However, this may cause a difference from the driver's expectation in the acceleration feeling or drivability of the electric vehicle. Specifically, when the enhancement is frequently alternated with the normal operation, the drivability is degraded. For this reason, there is a need for an enhanced application strategy that uses an enhanced function without degrading drivability.

Disclosure of Invention

The present invention provides an enhanced application control strategy that can both improve drivability and enhance acceleration performance of an electric vehicle. It is another object of the present invention to provide a method of controlling the driving of an electric vehicle by using an enhanced application control strategy.

According to an aspect of the present invention, a travel control method of an electric vehicle may include: enabling the controller to generate a motor torque command using the base torque command and a virtual shift intervention torque for generating a real shift feel 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 a real gear change feeling to be generated; wherein, in generating the real shift feeling, the intensifying control for operating the electric motor is executed so that the electric motor torque exceeding the allowable torque of the electric motor is generated during at least a part of the time when the real shift feeling is generated, so that the generating and intensifying control of the real shift feeling can be executed in conjunction.

With the running control method of an electric vehicle according to the present invention, torque boosting can be performed in conjunction with realization of a virtual multiple gear shift feel in a reducer-equipped electric vehicle. Therefore, the durability condition of the motor can be satisfied, and in addition, a higher torque than the normal torque of the motor may be generated, thereby increasing the acceleration. Further, the transient enhancing operation may be performed at a point in time that it can be expected to perform a process to achieve the virtual multiple shift feeling. Therefore, the sense of variation of the driver during driving can be reduced. Further, drivability can be improved while acceleration performance can be improved.

Drawings

The above and other objects, features and advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

fig. 1 is a block diagram showing a configuration of an apparatus for controlling an electric vehicle according to the present invention;

FIG. 2 shows a block diagram of input and output variables of a virtual shift model and intermediate variables of a virtual shift to implement a virtual shift function, according to the present invention;

fig. 3A and 3B show diagrams of a shift schedule map (schedule map) for determining a virtual target gear according to the invention;

FIG. 4 shows a diagram of one shift schedule map that may be used for upshifts and downshifts according to the invention;

FIG. 5 shows a maximum motor torque characteristic as a function of motor speed and a plot of the limiting torque for each virtual gear as may be calculated from FIG. 5 to reflect gear ratio information for each gear, according to the present invention

FIG. 6 shows a graph of an example of a virtual shift intervention torque characteristic curve in accordance with the present disclosure;

FIG. 7 illustrates a flow chart of a method of achieving augmentation through true shift feel coupling in accordance with the present invention;

FIG. 8 is a graph illustrating the excess and deficiency of limit torque for each virtual gear by comparison to a maximum motor torque characteristic curve, according to an exemplary embodiment of the present invention;

fig. 9 is a reference diagram showing a change over time in vehicle acceleration when a shift is performed in a vehicle equipped with an actual transmission, which represents acceleration generated when a shift is performed in an electric vehicle equipped with an actual transmission as shown in fig. 9;

FIG. 10 is a graph illustrating the state of virtual shift intervention torque applied at acceleration for achieving a real shift feel, illustrating acceleration simulations when executing a shift in an electric vehicle implementing virtual gears, in accordance with the present disclosure; and

fig. 11 and 12 each show a diagram of an example of adjusting the magnitude of the pushing pressure feeling when a real shift feeling is generated according to the present invention.

Detailed Description

It should be understood that the term "vehicle" or "vehicular" or other similar terms as used herein generally includes motor vehicles, such as passenger vehicles including Sport Utility Vehicles (SUVs), buses, trucks, various commercial vehicles, watercraft including a variety of boats and ships, aircraft, and the like, and includes hybrid vehicles, electric vehicles, plug-in hybrid electric vehicles, hydrogen-powered vehicles, and other alternative fuel vehicles (e.g., fuels derived from non-petroleum sources). As referred to herein, a hybrid vehicle is a vehicle having two or more power sources, such as a vehicle having both gasoline power and electric power.

While the exemplary embodiments are described as performing an exemplary process using multiple units, it should be understood that the exemplary process may also be performed by one or more modules. Further, it should be understood that the term controller/control unit means a hardware device including a memory and a processor, and is specifically programmed to perform the processes described herein. The memory is configured to store modules, and the processor is specifically configured to execute the modules to perform one or more processes described further below.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. 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, values, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, values, 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.

Unless specifically stated or otherwise apparent from the context, the term "about" as used herein is understood to be within the normal tolerance of the art, e.g., 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. All numerical values provided herein are modified by the term "about," unless the context clearly dictates otherwise.

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

When the expression "including a constituent element" is used throughout the specification, unless otherwise specifically stated, the expression means "further including any other constituent element" rather than "excluding any other constituent element". The present invention provides an enhanced application control method capable of improving drivability of an electric vehicle and acceleration performance thereof, and provides a travel control method of an electric vehicle using the enhanced application control method. Therefore, a method is provided in which the function of realizing the real gear change feeling in the electric vehicle and the function of executing the motor-enhanced mode are executed in conjunction with each other, and thus the transient enhancing torque is effectively utilized so that the driver does not feel the difference.

In general, the maximum allowable charge torque and the maximum allowable discharge torque of a motor (i.e., a driving motor) for driving an electric vehicle are determined with a normal state as a reference. Therefore, when the 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 the normal state as a reference) is generated for the short time. In other words, the motor torque is instantaneously (i.e., for a predetermined short time or less) increased to a torque higher than the allowable torque. This increase is referred to as "boosting" of the motor.

When a motor-enhanced and true-shift rhythmic feeling is achieved in this manner by using a technique in which the motor torque is instantaneously increased to a torque greater than the allowable torque in an electric vehicle, the durability requirement of the motor is satisfied, and a torque greater than the normal torque of the motor is generated, thereby increasing the acceleration of the vehicle. Further, the control may be performed such that the transient enhancing operation is performed at a point in time at which it can be expected that such an operation will be performed. Thus, the driving difference felt by the driver is reduced.

In an electric vehicle, the function of generating a real shift feel, which is based on a rhythmic feel of accelerating and decelerating the vehicle and is generated by the feel obtained by the virtual multi-speed transmission, is performed in conjunction with this inherent motor enhancement. The concept of the number of gears is not applicable to an electric vehicle that does not have a function of producing a real gear shift feeling. Thus, drivability is provided in a continuous and seamless manner.

However, when a real shift feel is produced during the running of the electric vehicle, that is, when the real shift feel is realized in a virtual shift situation (for example, a situation where a shift is performed in a vehicle equipped with a multi-speed transmission), a discontinuous point of acceleration and deceleration in drivability of the vehicle is produced in the process of realizing the real shift feel.

Efficient utilization of discrete points of vehicle acceleration and deceleration in terms of drivability may associate respective points of time at which enhancement is applied and at which enhancement is not applied with the discrete points. By this association, enhancement can be performed efficiently and naturally. Further, satisfactory driving ability of the vehicle can be ensured. The virtual shift function of the electric vehicle will be described below to help understand the present invention.

In the following description, the motor means a driving motor that drives a vehicle. According to the present invention, the vehicle as the 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 conventional vehicle equipped with an internal combustion engine, a typical electric vehicle (motor-driven vehicle) driven by an electric motor does not use a multi-speed transmission. Instead, in a typical electric vehicle, a reduction gear using a fixed gear is provided between the electric motor and the driving wheels.

The absence of a multi-speed transmission provides the following advantages: discontinuity in drivability does not occur when the shift is performed, and therefore smoothness in drivability is ensured. However, drivers who enjoy feeling a real tactile sensation, fun, excitement, responsiveness, etc., which may be provided by a multi-gear transmission, during driving may be bored. Therefore, in an electric vehicle equipped with a reduction gear instead of a multi-speed transmission, a technique is required which enables a driver to feel a real feeling of touch, fun, excitement, responsiveness, and the like (which can be provided by the multi-speed transmission).

In the case where the driver likes to feel the real sense of touch, fun, excitement, responsiveness, etc., which can be provided only by the multi-speed transmission, the function of realizing the real shift feeling enables the driver to feel a desired feeling in the same vehicle without going to drive another vehicle. Therefore, marketability of the electric vehicle can be improved and differentiated marketing can be performed.

In the existing electric vehicle, the driver cannot control the gear, and only by the speed and the input of the accelerator pedal, the driver can control the operation of the electric vehicle. Further, if the virtual shift function is implemented in a high-performance vehicle capable of racing travel, it is useful for speed regulation around a target, load motion management, and the like during driving. Therefore, in an electric vehicle not equipped with a multi-speed transmission, virtual shift control is executed by using a virtual shift model established within a controller, which controls a drive motor in such a manner as to generate and realize a virtual multi-speed shift feel.

In other words, under the virtual shift control, the virtual shift intervention torque and the limit torque for each virtual gear are determined from input variables by a virtual shift model whose input items are vehicle travel information collected in the vehicle while the vehicle is traveling. 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. Thus, a virtual multi-gear shift feel is achieved.

The virtual shift function is used to generate a real shift feeling that a driver can feel when shifting gears in a vehicle equipped with a multi-speed transmission, so that the multi-speed shift feeling is simulated while the electric vehicle not equipped with the multi-speed transmission is running. Therefore, the real gear change feeling is generated based on the preset variables (parameters) associated with the generation of the real gear change feeling, and in accordance with the driving input value of the driver and the vehicle state. Here, the real gear change feeling is a feeling generated by simulating the behavior and movement of the vehicle, which the driver can feel during the execution of gear change in the multi-speed transmission, and is generated and realized by operating the drive motor under the virtual gear change control. Here, the multi-speed transmission is one of an Automatic Transmission (AT), a Dual Clutch Transmission (DCT), and an Automatic Manual Transmission (AMT).

According to the present invention, the behavior and motion of the vehicle occurring during the execution of a shift operation in a vehicle equipped with one of these transmissions is generated and simulated by operating the drive motor. Therefore, a real shift feeling is provided, and the intensifying control is executed while the control for the real shift feeling is executed.

Fig. 1 shows a block diagram of a configuration of a device for controlling an electric vehicle according to the present invention, and shows a configuration of a device that performs control for a real gear change feeling and enhancement control. The control method according to the invention may include a virtual shift method that generates and implements a real shift feeling by motor control while the vehicle is running, the real shift feeling being generated by simulating a multi-gear shift feeling in an existing vehicle equipped with a multi-gear transmission.

First, the configuration of an apparatus for performing a virtual shift process is described. As shown in fig. 1, the control apparatus according to the present invention may include: a driving information detection unit 12 configured to detect vehicle travel information; a first controller 20 configured to generate and output a torque command based on the vehicle travel information detected by the driving information detection unit 12; and a second controller 30 configured to operate the driving device 41 according to the torque command output by the first controller 20.

In addition, the control device according to the present invention may further include an interactive interface unit 11 for the driver to select and input one of the turning on and off of the virtual gear shift function of the vehicle. In the following description, the control entity is divided into the first controller 20 and the second controller 30. However, a plurality of controllers or an integrated control assembly is collectively referred to as a controller. Therefore, it can also be understood that the control process according to the present invention is performed by the controller.

Any device that a driver can turn on and off a virtual shift function in an electric vehicle can be used as the interactive interface unit 11. Examples of the interactive interface unit 11 include operation devices such as buttons and switches provided in an electric vehicle, and input devices, touch screens, and the like 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 may be input into the first controller 20 through the interactive interface unit 11, respectively. Thus, the first controller 20 may be configured to detect whether the driver turns the virtual shift function on or off.

According to the present invention, the virtual gear shift function that generates and implements a real gear shift feeling while the electric vehicle is running can be executed only in the case where the driver turns on the virtual gear shift function through the interactive interface unit 11. Further, although not shown in fig. 1, the driver may 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 a vehicle provided in an electric vehicle.

The mobile device may be communicatively connected to a device within the vehicle, such as a first controller. Accordingly, a communication connection between the mobile device and the first controller 20 may be established using an input and output communication interface (not shown). The driving information detection unit 12 may be configured to detect vehicle travel information required to generate a motor torque command in the electric vehicle. Here, the vehicle travel information may include driving input information of the driver and vehicle state information.

According to an exemplary embodiment of the present invention, the driving information detecting unit 12 may include: an accelerator pedal detection unit configured to detect accelerator pedal input information according to an operation of an accelerator pedal by a driver; and a brake pedal detection unit configured to detect brake pedal input information according to a driver's operation of the brake pedal. Further, the driving information detection unit 12 may further include: a shift paddle (paddle shift) and a shift lever detecting unit; and a motor rotation speed detection unit configured to detect a rotation speed (hereinafter referred to as "motor rotation speed") of a motor, which is a driving device 41 that drives the electric vehicle.

Here, the accelerator pedal detection unit may be a conventional Accelerator Position Sensor (APS) mounted on an accelerator pedal, and configured to output an electric signal according to a state in which a driver operates the accelerator pedal. The brake pedal detection unit may be a conventional Brake Pedal Sensor (BPS) mounted on a brake pedal, and configured to output an electric signal according to a state in which a driver operates the brake pedal. The motor rotation speed detection means is a known resolver incorporated in the drive device (drive motor) 41.

In particular, the driving input information of the driver may include an accelerator pedal input value (APS value) detected by an accelerator pedal detection unit and a brake pedal input value (BPS value) detected by a brake pedal detection unit. Further, the driver's driving input information may also include shift pad input information according to the driver's operation of the shift pad and shift lever input information (shift position information represented by P-, R-, N-, or D-in accordance with the driver's operation of the shift lever).

The shift lever input information may be detected by the shift lever detection unit and the shift paddle input information may be input from the shift paddle into the first controller 20. Further, the vehicle state information may include the motor rotation speed detected by the motor rotation speed detection unit. The vehicle running information used by the torque command generating unit 21 to generate the basic torque command may also include the vehicle speed as the vehicle state information. In particular, although not shown in fig. 1, the driving information detecting unit 12 may further include a vehicle speed detecting unit configured to detect a current running speed of the vehicle. The vehicle speed detection unit may include a wheel speed sensor mounted on a driving wheel of the electric vehicle.

The first controller 20 may include: a torque command generation unit 21 configured to generate a basic torque command according to vehicle travel 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 according to vehicle travel information; and a final torque command generation unit 23 configured to generate a final torque command, the final torque command being generated by changing the basic torque command using the compensation torque command.

The base torque command is a motor torque command that is determined and generated based on driving information collected while the regular electric vehicle is running. The torque command generating unit 21 is a Vehicle Control Unit (VCU) in a conventional electric vehicle or a component thereof, and the torque command generating unit 21 is configured to generate a motor torque command based on driving information. Further in accordance with the present invention, the virtual shift controller 22 may be configured to determine, generate and output a virtual shift intervention torque command independent of the base torque command, the virtual shift intervention torque command being a compensation torque command for achieving only a true shift feel. The virtual shift controller 22 may be added as a component of the vehicle unit, or provided as a control component separate from the vehicle controller.

In the final torque command generation unit 23, the compensation torque command input from the virtual shift controller 22 may be used to change the basic torque command input from the torque command generation unit 21. In other words, the virtual shift intervention torque command, which is the compensation torque command, is added to the base torque command, thereby obtaining the final torque command. The second controller 30 may be configured to receive the torque command transmitted by the first controller 20, that is, the final torque command determined by the final torque command generating unit 23 of the first controller 20, and operate the driving device 41 accordingly.

According to the present invention, the driving device 41 is a motor (driving motor) that drives an electric vehicle, and the second controller 30 is a well-known Motor Control Unit (MCU) in a conventional electric vehicle that drives the motor through an inverter and controls the operation of the motor. On the other hand, according to the present invention, a virtual shift model is set and input into the virtual shift controller 22, the input items of the virtual shift model are set as the vehicle running information collected in the electric vehicle, and the virtual shift model determines and outputs a virtual shift intervention torque command.

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

In the virtual shift controller 22, the values of the intermediate variables can be calculated from the model input variables using the virtual shift model. Further, it is possible to determine a torque command for generating and realizing only a real gear shift feeling and a limit torque of each virtual gear reflecting gear ratio information according to the value of the intermediate variable, and output the torque command and the limit torque. The torque command used only to generate and achieve the actual shift feel is not only the virtual shift intervention torque command, but also a compensation torque command that is used to change the base torque command.

Fig. 2 shows that accelerator pedal input information (APS value information), brake pedal input information (BPS value information), shift paddle input information, shift lever input information (shift position information indicated by P-, R-, N-, and D-representations), and motor rotation speed (omega) information, which are vehicle travel information, are input variables of the virtual shift model (M). Fig. 2 also shows intermediate variables for executing the virtual shift function in the virtual shift model (M), i.e. model intermediate variables for generating a real shift feel, which are obtained from the input variables in the virtual shift model.

According to an exemplary embodiment of the present invention, the model intermediate variables obtained by the input variables include a virtual vehicle speed (SpdVir), a downshift virtual vehicle speed (SpdVirDn), a virtual target gear (TarGe), a target gear in a virtual manual shift mode (TarGeMan), a virtual current gear (CurGe), a virtual engine speed (omega vir), gear ratios for the virtual gears (rG1, rG2, etc. up to rGi), a virtual longitudinal reduction gear ratio (rFg), a target input speed based on the virtual target gear (omega tar), a target input speed based on the virtual current gear (omega cur), and a virtual shift progress ratio (xproges).

The "input speed" herein means a virtual engine speed that forms an input speed of a virtual transmission when it is assumed that the virtual transmission and the virtual engine exist in the electric vehicle. Thus, the "target input speed based on the virtual target gear" represents the virtual engine speed for the virtual target gear, and the "target input speed based on the virtual current gear" represents the virtual engine speed for the virtual current gear. According to the invention, the intermediate variables for the virtual gear change are independent of the physical values of the actual hardware of the electric vehicle, but are only used to achieve a real gear change sensation.

According to the present invention, physical variables actually physically included in a drive system of an electric vehicle or used as actual measured values include input variables (an APS value, a BPS value, a shift paddle input value, and a shift lever input value), a motor rotational speed (omega), a virtual shift intervention torque (tqltv), and a limit torque (tqLmt) of each virtual gear. Further, according to an exemplary embodiment of the present invention, the output variables of the virtual shift model (M) include a virtual shift intervention torque command (compensation torque command) (Tqltv) for providing and implementing a real shift feel.

In addition, the output variables of the virtual shift model (M) may also include the limit torque (tqLmt) for each virtual gear. Furthermore, according to an exemplary embodiment of the invention, the output variables of the virtual shift model (M) may further comprise at least one or several of the intermediate variables for the virtual shift. For example, the output variables of the virtual shift model (M) may further include a virtual target gear (TarGe), a virtual current gear (CurGe), and a virtual engine speed (omega vir) among the intermediate variables for the virtual shift.

The virtual target gear (TarGe), the virtual current gear (CurGe) and the virtual engine speed (omega vir) output from the virtual shift model (M) are transmitted to a cluster controller (not shown) and made a segment of cluster display information displayed on a cluster device (not shown). The virtual shift intervention torque command and the limit torque for each virtual gear (e.g., the limit torque for the current gear) output from the virtual shift controller 22 are input to the final torque command generating unit 23, and then used in the final torque command generating unit 23 to generate the final torque command according to the basic torque command.

In other words, in the final torque command generation unit 23, the basic torque command is defined as the limit torque of each virtual gear, if necessary. When the basic torque command is lower than the limit torque value, the basic torque command is used as it is. However, when the base torque command is equal to or greater than the limit torque value, the base torque command may be defined as the limit torque value. In this way, the basic torque command defined within the limit torque of each virtual gear in the final torque command generation unit 23 is then added to the virtual shift intervention torque command, and the resultant torque command becomes the final motor torque command.

When the base torque command is equal to or greater than the limit torque value, the final motor torque command may be determined as a 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 may be transmitted to the second controller 30, and the second controller 30 may be configured to operate the motor according to the final motor torque command.

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

In the example of fig. 2, it is shown that a virtual longitudinal reduction gear ratio is included in the intermediate variables for virtual gear shifting. However, according to an exemplary embodiment of the present invention, the virtual longitudinal reduction gear ratio is a preset value. Further, in the virtual shift model, a downshift virtual vehicle speed (SpdVirDn) is generated. 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) may be calculated by applying a preset scale factor and a deviation value to the virtual vehicle speed (SpdVir).

However, when the upshift and downshift shift schedule maps are separately set for use, it is possible to safely 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 invention, in order to achieve a normal hysteresis effect, the downshift virtual vehicle speed (SpdVirDn) may be determined to be a value generated by adding a positive deviation value to a value obtained by multiplying the virtual vehicle speed (SpdVir) by a scaling factor greater than 1.

Fig. 3A and 3B show shift schedule maps for determining a virtual target gear (TarGe) according to the invention. Fig. 3A and 3B show an upshift shift schedule map and a downshift shift schedule map that are separately provided. 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). Specifically, the vehicle speed of the horizontal axis is a virtual vehicle speed (SpdVir) as a reference vehicle speed. In this way, the input items of the shift schedule map may be set as accelerator pedal input values (APS values) indicating 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) may be determined from the shift schedule map.

As shown in fig. 3A and 3B, in the case where the upshift and downshift shift schedule maps are provided separately from each other, one virtual vehicle speed may 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 rotational speed (omega m) and the virtual longitudinal deceleration transmission ratio (rFG).

In this way, when the upshift and downshift shift schedule maps are used separately from each other, the virtual target gear (TarGe) can be determined from the virtual vehicle speed (SpdVir) as the reference vehicle speed and from the accelerator pedal input value (APS value). However, when one shift schedule map is used for upshifting and downshifting, the virtual target gear (TarGe) can be determined using the downshift virtual vehicle speed (SpdVir) separately from the virtual vehicle speed (SpdVir) as the reference vehicle speed.

Fig. 4 shows a shift schedule map according to the invention that can be used for both upshifts and downshifts. One shift schedule map shown in fig. 4 can be used both during upshifts and downshifts. In particular, at the time of upshift, a virtual vehicle speed (SpdVir) as a reference vehicle speed, which becomes an upshift virtual vehicle speed, is used as an input variable for determining a virtual target gear (TarGe) in the shift schedule map. Furthermore, at 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).

In other words, when one shift schedule map is used, at the time of upshift, the virtual target gear (TarGe) can be determined from the virtual vehicle speed (SpdVir) as the reference vehicle speed and from the accelerator pedal input value (APS value). Further, at the time of downshift, the virtual target gear (TarGe) may be determined from the downshift virtual vehicle speed (SPdVirDn) and the accelerator pedal input value (APS value). In other words, in the shift schedule map of fig. 4, the vehicle speed on the horizontal axis is the virtual vehicle speed (SpeVir) as the reference speed at the time of upshift. Further, at the time of downshift, the vehicle speed of the vertical axis is a downshift virtual vehicle speed (SpdVirDn).

The vertical axis in fig. 3A and 3B and fig. 4 represents the accelerator pedal input value, i.e., the APS value (%) as described above. However, instead of the accelerator pedal input value, the vehicle load value for the other may be used as the value on the vertical axis in the shift schedule map. In other words, the vertical axis in the shift schedule map may represent a brake pedal input value (BPS value) or a basic torque command, instead of an accelerator pedal input value. The vertical axis in the shift schedule map may represent input variables in the shift schedule map for determining the virtual target gear with the vehicle speed.

When the virtual vehicle speed (SpdVir) as the reference vehicle speed is the upshift virtual vehicle speed, the downshift virtual vehicle speed (SpdVirDn) is determined as a value resulting from adding the deviation value (β) to a value obtained by multiplying the upshift virtual vehicle speed (SpdVir) by the scaling factor (α), as in the following equation 1.

Equation 1

SpdVir＝SpdVirDn×α+β

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

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

Furthermore, the final target gear in the virtual shift function may be calculated in a virtual shift model (M) within the virtual shift controller 22. As described above, fundamentally, in the automatic shift mode, the target gear determined from the shift schedule map may be determined as the virtual target gear (TarGe). However, in the manual shift mode, the target gear (TarGeMan) in the virtual manual shift mode, which is determined according to the driver's shift lever input or shift paddle input, may be determined as the virtual target gear (TarGe).

As described above, the method of determining the target gear from the shift schedule map in the automatic shift mode (not the manual shift mode) is to use the 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 is here a map whose input items are set as pieces of vehicle load value information, such as a virtual vehicle speed and an accelerator pedal input value, and in which a virtual target gear corresponding to each combination of the pieces of vehicle load value information is preset. In addition to an accelerator pedal input value (APS value) as driving input information of the driver, a brake pedal input value (BPS value), a basic torque command, and the like are used as vehicle load value information.

As described above, the virtual vehicle speed (SpdVir) determined from the virtual longitudinal reduction gear ratio (rFg) and the real motor rotational speed (omega) or the downshift virtual vehicle speed (SpdVirDn) determined from the virtual vehicle speed is used as the reference speed, which is used as an input item of the shift schedule map. When the target gear is determined as described above, two target gears, that is, two target gears determined based on the virtual vehicle speed (SpdVir) as the reference speed and the downshift virtual vehicle speed (SpdVirDn), respectively, occur at the current point in time.

In particular, two values may be used to determine the final target gear. In the determination method, a value of the target shift position determined from the virtual vehicle speed (SpdVir) is determined as a valid value only when such a value is increased to a value larger than the previous shift position (for example, changed from the first shift position to the second shift position). Therefore, the target gear determined from the virtual vehicle speed (SpdVir) can be determined and replaced with the final virtual target gear (TarGe).

Likewise, a value of the target shift range determined from the downshift virtual vehicle speed (SpdVirDn) is determined to be a valid value only when such value decreases to a value smaller than the previous shift range (e.g., changes from the second shift range to the first shift range). Therefore, a target gear determined from the downshift virtual vehicle speed (SpdVirDn) may be determined and replaced by the final virtual target gear (TarGe). For this purpose, it is necessary to calculate the virtual target gear (TarGe) as a value falling within a range from the lowest gear to the highest gear.

On the other hand, in the virtual shift model (M) within the virtual shift controller 22, a delay target gear having a value produced by delaying a fixed delay time may be determined from the virtual target gear (TarGe). The fixed delay time is a preset time here, and represents the following time: during this time, the gear for the virtual engine speed (omega vir), which gear is planned 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 inertia phase starts in a real transmission. In a virtual shift model (M) within the virtual shift controller 22, a change in the target gear (TarGe) may be detected to calculate a virtual shift progress ratio (xprogess).

Here, the change of the target gear means that a new virtual target gear different from the current gear is determined according to shift paddle input information or shift lever input information in the shift schedule map or the manual shift pattern. The controller may be configured to count from the point in time at which the target gear is changed (e.g., the point in time at which a new virtual target gear is determined) to time 0. The gear shift schedule ratio (xprogers) can be determined as a percentage of the timing time relative to the preset total gear time. The shift schedule is increased to 100%.

The time point at which the target gear is changed represents a time point at which a new virtual target gear is determined from the virtual current gear (which is the previous target gear) through the shift schedule map. In this way, the timer starts counting time, in which the time point of the target gear change is set to time 0. However, the time point at which the timing is started may be replaced with the time point at which the delay in the target gear change occurs.

In other words, when the changed virtual target gear is determined, the controller may be configured to count time from a time point of a delay time elapsed after the virtual target gear is determined. The controller may then be configured to determine the virtual shift schedule ratio in the same manner using the timed time. Alternatively, as another method, in terms of expression, it is also possible to use a percentage that indicates at which position between the following two the value of the current virtual engine speed (omega vir) obtained in real time during execution of the gear shift is located: a target input speed (omega cur) based on the virtual current gear (e.g., virtual engine speed for the virtual current gear) and a target input speed (omega tar) based on the virtual target gear (e.g., virtual engine speed for the virtual target gear).

In other words, at the time point when the virtual target gear position is determined, the virtual shift schedule ratio may be determined as a percentage of a speed difference between a real-time virtual engine speed (omega vir), which is generated during execution of the shift, and a target input speed (omega cur) based on the virtual current gear position, with respect to a speed difference between: a speed difference between a target input speed (omega tar) based on the virtual target gear position and a target input speed (omega cur) based on the virtual current gear position.

In the virtual shift model (M) within the virtual shift controller 22, fundamentally, the virtual engine speed (omega cur) can be determined using the virtual vehicle speed (SpdVir) as the reference vehicle speed and the virtual gear ratio (rGi) for the virtual current gear. In other words, the virtual engine speed (omega cur) may be obtained by a value resulting from multiplying the virtual vehicle speed (SpdVir) and the virtual gear ratio (rGi) for the virtual current gear together. Alternatively, the virtual engine speed (omega cur) may be obtained by a value resulting from multiplying the drive system speed (e.g., the motor speed) and the virtual gear ratio (rGi) for the virtual current gear together.

Further, during execution of the shift from the time point of change of the target gear (i.e., the time point of start of the shift), the virtual engine speed (omega vir) may be determined from the target input speed (omega cur) based on the virtual current gear (i.e., virtual engine speed for the virtual current gear) and the target input speed (omega tar) based on the virtual target gear (i.e., virtual engine speed for the virtual target gear). At this time, the virtual vehicle speed (SpdVir) at the time point of the target gear change and the virtual gear ratio (rGi) for the virtual current gear (CurGe) may be used to obtain the target input speed (omega cur) based on the virtual current gear.

The target input speed (omega tar) based on the virtual target gear may be obtained using the virtual vehicle speed (SpdVir) at the time point of changing the target gear and the virtual gear ratio (rGi) for the virtual target gear (TarGe). Subsequently, during execution of the gear shift, the obtained virtual engine speed (omega vir) may be a value generated by applying a preset change rate limit to the target input speed based on the virtual current gear.

According to the present invention, the current virtual engine speed (omega vir) to be reached in the course of executing the gear shift may be obtained from the real-time virtual vehicle speed, and may be determined as a value that varies within a preset variation rate limit (a value for defining the variation rate) ranging from a virtual speed based on the current gear (target input speed based on the virtual current gear) to a virtual speed based on the target gear (target input speed based on the virtual target gear).

Further, subsequently, as the gear shift progresses to some extent, the virtual engine speed (omega vir), which is set to the target input speed (omega cur) based on the virtual current gear (virtual engine speed for the virtual current gear), is replaced with the target input speed (omega tar) based on the virtual target gear (virtual engine speed for the virtual target gear). As another method, the virtual engine speed (omega vir) may be calculated by using the change rate limit for a 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 previously calculated delay target gear.

On the other hand, in the virtual shift model (M) within the virtual shift controller 22, basically, the virtual current gear (CurGe) represents the current gear of the previous-time gear, that is, after the current gear that is active before the start of the shift until the current shift completion condition is satisfied. In other words, the value of the current gear may be maintained until the shift completion condition is satisfied. The virtual target gear determined from the shift schedule map may be maintained as the target gear achieved after the gear shift is completed.

However, when the shift completion condition is satisfied after the shift is started, the virtual current gear (CUrGe) that was active before the satisfaction is replaced with the virtual target gear (TarGe). From the time point when the shift completion condition is satisfied, the previous target gear becomes the current gear.

At this time, the shift completion condition may include one or more of the following conditions:

1) provided that the value of the virtual shift progress ratio (xprogess) is 100%;

2) provided that the value of the virtual shift progress ratio (xprogess) is reset to 0%;

3) providing that a value of the virtual shift progress ratio (xprogrress) is equal to or greater than a fixed value;

4) provided that the difference between the virtual engine speed (omega vir) and the virtual engine speed (omega tar) 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

5) the condition is that a value obtained by multiplying a virtual vehicle speed (SpdVir) as a reference vehicle speed by a virtual gear ratio (rGi) corresponding to the delay target gear is the same as a virtual engine speed (omega vir) obtained by using a change rate limit value for the value obtained by the multiplication, or that a difference between the value obtained by the multiplication and the virtual engine speed (omega vir) is equal to or smaller than a fixed value.

At this time, regarding the "condition for resetting the value of the virtual shift progress ratio (xprogers) 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 immediately resets it to 0%, it is determined as described above that the time point at which the resetting to 0% is performed is the time point at which the shift is completed. In other words, the shift schedule ratio remains at 0% until after the shift event is again initiated. However, it is possible to determine that the time point at which the shift schedule first reaches 0% is itself the time point at which the shift is completed.

As described above, completion of the shift may be determined based on the virtual shift progress ratio (xprogers), and may be determined based on the virtual engine speed. It may also be determined that the shift completion condition is satisfied when the virtual engine speed converges to the virtual engine speed for the virtual target gear such that a difference between the two is equal to or smaller than a fixed value.

Next, in a vehicle equipped with a real transmission, the gear ratio is reduced each time an upshift is performed. Thus, the torque multiplier effect between the front and rear gears in the transmission is reduced. Therefore, eventually, even if the engine generates the same torque, the acceleration that is finally obtained decreases. To simulate this effect, according to the invention, the limit torque (tqLmt) for each virtual gear can be calculated and used to define the torque command.

At this time, in the virtual shift model (M) within the virtual shift controller 22, the limit torque (tqLmt) (limit torque for the current gear) for each virtual gear may be calculated by multiplying together 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. Further, the limit torque (tqLmt) of each virtual gear is set in two directions, that is, in the driving direction and the regenerative power generation direction of the motor. This is achieved by using two limit torque setting parameters.

In order to apply the limit torque and thereby control the motor torque, it is possible to define the motor torque in the driving direction as a value of the limit torque for the driving direction (tqLmt), and to define the motor torque in the regenerative generation direction as a value of the limit torque for the regenerative generation direction (tqLmt).

There is another method. Three types of motor torque commands, i.e., a regenerative-power-generation motor torque command, a coasting motor torque command, and a driving motor torque command, are generated and added to generate a basic torque command. Then, while driving, the torque command is defined as the value of the limit torque (tqLmt) for the driving direction. At the time of coasting and at the time of regenerative power generation, the torque command is defined as the value of the limit torque (tqLmt) for the regenerative power generation direction. Of course, the values of the regenerative power generation torque command and the coasting torque command may be 0 at the time of driving, and the value of the driving torque command may be 0 at the time of regenerative power generation or coasting.

Further, in order not only to define the maximum magnitude of the torque but also to simulate a ratio effect applied proportionally, in determining a value between an accelerator pedal input value (APS value) and a driving torque, an application ratio of the accelerator pedal input value with respect to a value of a limit torque (tqLmt) for a driving direction is used instead of an application ratio of the accelerator pedal input value (APS value) with respect to a maximum motor torque.

Further, in addition to the method of determining the torque command using a simple ratio of the accelerator pedal input value (APS value) to the limit torque (tqLmt) for each virtual gear, the torque command may be determined using a torque ratio that is a function of a preset accelerator pedal input value of the limit torque (tqLmt). 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 command may be determined as 20%, 50%, and 80% of the limit torque (tqLmt), respectively. However, when the APS values are 20%, 50%, and 80%, respectively, if the torque ratios mapped to the APS values are 40%, 70%, and 85%, respectively, the torques of the basic torque command may be determined as 40%, 70%, and 85% of the limit torque (tqLmt), respectively.

Fig. 5 shows a diagram of the maximum motor torque characteristic according to the motor speed and the limit torque for each virtual gear (gears 1, 2, 3, 4, 5, etc.) according to the invention. Fig. 5 shows that the higher the motor speed, the higher the gear (shift), and the higher the gear, the lower the maximum motor torque. Furthermore, fig. 5 shows that the higher the gear, the lower the transmission ratio and that the final wheel transfer torque in the high gear is reduced compared to the low gear. The maximum motor torque characteristic curve is a curve showing a preset maximum allowable torque for each motor rotation speed. The limit torque for each virtual gear may be calculated to reflect gear ratio information for each gear.

Fig. 5 shows various examples in which the limit torque of each virtual gear is determined. As described above, the limit torque for each virtual gear (limit torque for the current gear) may be calculated as a value obtained by multiplying together 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.

This means that the magnitude of the limit torque of each virtual gear can be set according to the limit torque setting parameter value. Fig. 5 shows that the limit torque for 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 fig. 5, the limit torque of each virtual gear may be set to have a value greater than the corresponding maximum motor torque on the maximum motor torque characteristic curve. In particular, maximum performance of the motor can be achieved.

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

Further, the value of the limit torque of each virtual gear may be set to be smaller than the corresponding value on the maximum motor torque characteristic curve in all the intervals of the motor rotation speed. In particular, it is not possible to achieve maximum performance of the electric motor, but the effect of the difference in transmission ratio between the gears can be achieved to the greatest extent. On the other hand, the final torque command generating unit 23 of the first controller 20 may be configured to receive the basic torque command resulting from the addition of the motor torque commands from the torque command generating unit 21, and receive the virtual shift intervention torque command from the virtual shift controller 22.

Further, the final torque command generating unit 23 may be configured to correct the basic torque command generated in the torque command generating unit 21 using the virtual shift intervention torque command generated in the virtual shift controller 22. At this time, the final torque command generating unit 23 may be configured to additionally add a virtual shift intervention torque command (which is a compensation torque command for producing a real shift feel) to the base torque command (which is produced by adding the motor torque commands), thereby producing a final torque command.

FIG. 6 shows a graph of an example of a virtual shift intervention torque profile according to the present disclosure. Accordingly, the second controller 30 may be configured to receive the final torque command generated and output by the final torque command generating unit 23 of the first controller 20 and then operate the inverter according to the received final torque command, thereby operating the driving device 41. As a result, a vehicle actuation phenomenon that occurs according to the shift effect when virtual shifting is performed is achieved in a manner similar to when shifting is performed in a real transmission.

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 the virtual shift progress ratio (xprogess) is set as an argument. Alternatively, the virtual shift intervention torque (tqItv) may be provided by a physical value mapping model based on: a virtual engine speed (omega vir), a target input speed (omega cur) based on the virtual current gear (i.e., a virtual engine speed for the virtual current gear), and a target input speed (omega tar) based on the virtual target gear (i.e., a virtual engine speed for the virtual target gear).

Further, in calculating the virtual shift intervention torque command, the shape of the virtual shift intervention torque should be different depending on the type of transmission and the shift classification. Types of transmissions include Automatic Transmissions (AT), Dual Clutch Transmissions (DCT), Automated Manual Transmissions (AMT), and the like. Further, the shift categories include power-on upshift (power-off upshift), power-off downshift (power-on downshift), power-on downshift (kick-down), power-off downshift (power-off downshift), and near-stop downshift (near-stop downshift).

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

Further, when the basic torque command is larger than the preset reference torque value, it is a case of a power supply type. In contrast, when the basic torque command is smaller than the preset reference torque value, it is a case of the power-off type. As a result, according to the present invention, when a current shift classification is determined based on a virtual current gear, a virtual target gear, etc., a virtual shift intervention torque profile corresponding to the current shift classification is selected from the virtual shift intervention torque profiles for the shift classification. The virtual shift intervention torque for producing a real shift feel can be determined in real time from the selected virtual shift intervention torque profile.

At this time, a value of virtual shift intervention torque corresponding to the current virtual shift schedule ratio may be determined based on the selected virtual shift intervention torque characteristic. The virtual shift intervention torque feature is information preset for each shift classification to be added to the virtual shift model (M) within the virtual shift controller 22. Virtual shift intervention torque characteristics that vary according to the type of transmission and shift classification may be preset.

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

Generally, it is natural that the greater the magnitude of the motor torque (i.e., the base torque command), the greater the magnitude of the virtual shift intervention torque; this is because the higher the gear, the lower the ratio between gears, so the magnitude of the virtual shift intervention torque should be reduced; and because the higher the virtual engine speed, the higher the degree of speed reduction and increase when the shift is performed, the magnitude of the virtual shift intervention torque should also be increased. On the other hand, as described above, according to the present invention, the boosting is defined as instantaneously generating a motor torque larger than the maximum allowable torque (which is determined with the normal state as a reference).

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

The running control method of an electric vehicle according to the present invention may include: generating a motor torque command using the base torque command and a virtual shift intervention torque for generating a real shift feel while the electric vehicle is driven; and operating a motor for driving the electric vehicle according to the generated motor torque command, thereby generating a real gear shift feeling; wherein, in generating the real shift feeling, the intensifying control (which controls the operation of the electric motor) is executed so that the electric motor torque exceeding the allowable torque of the electric motor is generated during at least a part of the time during which the real shift feeling is generated, so that the generation of the real shift feeling and the intensifying control are executed in conjunction with each other.

At this time, at least a part of the time during which the real shift feel is generated may be an interval that simulates an inertia phase during a virtual shift. According to the present invention, the methods for achieving the combination of producing the virtual shift feel and the transient boost are roughly divided into two methods:

1) an excess of the maximum output torque exceeding the virtual gear is achieved,

2) the torque phase characteristic of the virtual shift intervention torque is realized, and the thrust or retardation feeling of the inertia phase at the time of acceleration is realized.

Fig. 7 shows a flow chart of a method according to the invention for achieving an enhanced and real gear shift feel in combination. First, implementation of the excess portion of the maximum output torque exceeding the virtual gear will be described. In a vehicle equipped with a real transmission, an upshift from a low gear to a high gear causes a reduction in the gear ratio. 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 acceleration finally obtained decreases. When the virtual gear shifting function is realized, the torque multiplication effect should be simulated. To implement the virtual shift function, the limit torque of each virtual gear is calculated and used.

As described above with reference to fig. 5, the limit torque of each virtual gear is used by executing the "cover type" technique, the "intersection type" technique, or the "cut type" technique. In the "covered type" technique, the limit torque for each virtual gear used is higher than the corresponding limit torque on the maximum motor torque characteristic curve. In the "intersection type" technique, the limit torque for each virtual gear used is equal to the corresponding limit torque on the maximum motor torque characteristic curve. In the "cut-off type" technique, the limit torque for each virtual gear used is lower than the corresponding limit torque on the maximum motor torque characteristic curve.

The maximum motor torque characteristic curve here is a curve showing the maximum allowable torque preset for each motor rotation speed using the normal state as a reference, and is a maximum torque characteristic curve generated when no strengthening is performed. According to the present invention, in order to perform effective reinforcement using the virtual gears, it is preferable to set the limit torque of each virtual gear to the torque on the maximum motor torque characteristic curve.

In other words, according to the present invention, in order to perform the intensifying control, in the above-described technique of calculating the limit torque of each virtual gear, "intersection type" technique in which the curve of the limit torque of each virtual gear is plotted so as to intersect with the maximum motor torque characteristic curve may be applied. In the intersection 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 the motor rotation speed, and to this end, 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 the other intervals of the motor rotation speed.

Fig. 8 shows a graph of the excess and deficiency of the limit torque for each virtual gear, which are generated by comparison with the maximum motor torque characteristic curve as a function of the motor speed when the "intersection type" technique is applied, according to an exemplary embodiment of the present invention. As shown, for the control, a torque excess section in which the limit torque of each virtual gear exceeds the maximum motor torque corresponding to the current motor rotation speed is set as a section in which the boosting is performed. Further, for the control, a torque shortage section in which the limit torque of each virtual gear is smaller than the maximum motor torque corresponding to the current motor rotation speed is set as a section in which the load is adjusted without performing the boosting. Thus, the boost is turned on and off in conjunction with the real shift feel.

At this time, the ratio of the torque excess portion in the excess interval in which the strengthening is performed to the torque deficiency portion in the deficiency interval in which the strengthening is not performed is adjusted according to the specification of the motor. Based on the "intersection type" technique, it can be determined whether the limit torque of each virtual gear as described above is set in a manner similar to when the "cover type" technique is applied or in a manner similar to when the "cut type" technique is applied. This may apply not only to the torque in the acceleration direction (motor discharge direction and drive direction) but also to the torque in the deceleration direction (motor charge direction and regeneration direction).

Further, the limit torque of each virtual gear may be adjusted according to the state of the PE part (i.e., the current temperature of the PE part such as the motor), the temperature of the coolant, and the like, thereby adjusting the ratio of the torque excess portion to the torque deficiency portion. For example, the "intersection type" technique is fundamentally applied to set the magnitude of the limit torque of each virtual gear that varies with the motor speed so that the torque-exceeding portion and the torque-lacking portion alternately appear in a repeated manner. However, when the strengthening is limitedly performed due to the high temperature, the magnitude of the limit torque may be relatively set in a similar manner as when the "cutoff type" technique is performed. Conversely, when the temperature is low and it is easy to perform cooling, the magnitude of the limit torque is set in a similar manner as when the "cover type" technique is performed.

As described above, the limit torque (tqLmt) for each virtual gear may be calculated by multiplying together the virtual gear ratio (rGi), which corresponds to the virtual current gear (CurGe), the virtual longitudinal reduction gear ratio (rFg), and the limit torque setting parameter. As described above, the adjustment of the limit torque setting parameter enables the limit torque of each virtual gear to be adjusted. Next, implementation of the torque phase characteristic of the virtual shift intervention torque, and implementation of the thrust feeling or the retardation feeling of the inertia phase at the time of acceleration will be described.

Fig. 9 shows a reference diagram of the change over time of the vehicle acceleration when a gear shift is performed in a vehicle equipped with a real transmission. Fig. 10 shows a diagram of the state of the virtual shift intervention torque applied during acceleration according to the invention for realizing a real shift feel, i.e. for simulating a change in vehicle acceleration as shown in fig. 9 during acceleration. In a vehicle equipped with a real transmission, the output torque of the transmission changes due to the interaction of friction elements and the change in input torque of the transmission when a shift is performed. This change occurs during the torque phase and the inertia phase when the shift is performed.

Furthermore, in the inertia phase, when a shift is performed, the following occurs: due to the speed change in the transmission under inertia of the previous gear, an additional acceleration/deceleration torque different from the input torque is applied in the transmission towards the next gear. When an upshift is performed in a vehicle equipped with a real transmission, if the inertia of the previous gear in the transmission causes deceleration, a torque in the acceleration direction is applied toward the output shaft. This application is referred to as a push-on feel. In contrast, when a downshift is performed, if the inertia of the previous gear in the transmission causes acceleration, torque in the direction of deceleration is applied toward the output shaft. This application is called a feeling of blocking.

Fig. 10 shows an example of an enhanced on/off control for simulating vehicle acceleration when a shift is performed according to the present invention in an electric vehicle that realizes a real shift feeling, and shows an example in which enhancement of a torque excess portion is performed to generate a thrust feeling. In fig. 10, the broken line indicates the maximum allowable torque (which is determined with the normal state as a reference) generated when no strengthening is performed. The torque excess portion represents a torque magnitude at which the motor torque indicated by the solid line exceeds the corresponding maximum allowable torque indicated by the broken line.

Further, the torque shortage portion indicates that the motor torque indicated by the solid line falls to a torque magnitude smaller than the corresponding maximum allowable torque indicated by the broken line. The solid line in fig. 10 represents the motor torque according to the present invention, which is used to simulate the acceleration when a shift is performed in an electric vehicle equipped with the transmission shown in fig. 9. The motor torque indicated by the solid line is a virtual shift intervention torque (compensation torque) for realizing a real shift feel.

Further, the torque indicated by the solid line in fig. 10 may be a torque command, and according to the present invention, it is a virtual shift intervention torque command for jointly executing the enhanced and the real shift feel. Specifically, the torque indicated by the solid line in fig. 10 is a torque command output by the virtual shift controller 22 of the first controller 20 among the constituent elements of fig. 1. According to the present invention, when the second controller 30 operates the motor according to the final torque command generated in the first controller 20, the state of the vehicle acceleration as shown in fig. 9 is excited.

According to the present invention, it is also possible to simulate the torque variation as described above while realizing a real gear change feeling. Thus, a method of opening and closing the boost in conjunction with torque variation is presented. By this method, the strategy of performing the enhancement can be applied bi-directionally in a direction that exceeds the maximum allowable charge torque and the maximum allowable discharge torque (to simulate a real shift feel).

Fig. 10 shows that an enhanced non-execution section (enhanced off-section) in which the motor torque is reduced below the existing maximum allowable torque determined with reference to the normal state and an enhanced execution section (enhanced on-section) in which the motor torque is increased beyond the existing maximum allowable torque are repeatedly alternated. In fig. 10, the insufficient torque portion in the reinforcement non-execution section is that the motor torque (torque command) falls to a torque magnitude lower than the maximum allowable torque at the time of generation of the real shift feeling. Therefore, during the virtual shift, the space for the motor torque command is as large as the torque shortage portion. The motor torque command here has a value smaller than the maximum allowable torque. This helps to cool PE components, such as the motor.

On the other hand, the torque excess portion in the execution-enhanced section is a torque magnitude at which the motor torque (torque command) exceeds the maximum allowable torque. The motor torque command is generated such that the maximum allowable torque is temporarily exceeded when a real shift feel is produced during the virtual shift. Therefore, in the process of achieving the virtual shift feeling, the motor torque exceeding the maximum allowable torque can be output. Therefore, the pushing feeling can be realized while the motor reinforcement is performed.

Fig. 11 and 12 each show a diagram of an example of adjusting the magnitude of the pushing pressure feeling when a real gear shift feeling is generated according to the present invention. Fig. 11 and 12 each show a motor torque characteristic curve (a curve for a virtual shift intervention torque command) showing a virtual shift intervention torque when an upshift is performed. In fig. 11 and 12, the maximum allowable torque characteristic curve is the maximum allowable discharge torque characteristic curve.

When a downshift is executed, a motor torque characteristic curve (e.g., a curve for a virtual shift intervention torque command) is obtained that is generated by: the illustrated motor torque characteristic curve generated when an upshift is performed is reversed upside down. At this time, the maximum allowable torque characteristic curve becomes the maximum allowable charging torque characteristic curve. In executing the downshift, with respect to the virtual shift intervention torque, the feeling of retardation may be achieved by a torque excess portion that exceeds the maximum allowable charge torque.

In other words, when the upshift is performed, the pushing feeling in the inertia phase can be achieved by the torque excess portion that exceeds the maximum allowable discharge torque. However, when the downshift is performed, the feeling of retardation in the inertia phase can be achieved by a torque excess portion that exceeds the maximum allowable charging torque (e.g., an excess portion that exceeds the absolute value of the charging torque).

Furthermore, according to the present invention, the characteristics of the virtual shift intervention torque may be adjusted depending on the operating state of the PE component (i.e., the current temperature of the PE component (e.g., electric motor)), the temperature of the coolant used to cool the PE component (e.g., electric motor), and the like. Therefore, 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 shown in the example of fig. 11, the magnitude of the pushing feeling or the blocking feeling may be set to an increased magnitude. Further, when the strengthening is performed limitedly due to the high temperature, as shown in the example of fig. 12, the magnitude of the pushing feeling or the blocking feeling may be set to be reduced. Further, in addition to the method by adjusting the magnitude of the pushing feeling or the blocking feeling, the ratio of the limit torque excess portion to the limit torque deficiency portion is adjusted by: methods for adjusting the duration of the push feel or the hold feel (the duration of the torque override portion), methods for adjusting the offset of the virtual shift intervention torque profile, and the like.

Referring to fig. 7, when the virtual shift function is turned on, the motor boost function may also be turned on. When the virtual shift function is turned on and the boost is turned on, the controller may be configured to determine whether to additionally perform the boost or whether to restrict the boost from being performed. Further, when the strengthening can be additionally performed, the strengthening open interval and the torque excess portion are increased, as shown in fig. 11. Further, when the intensification is restricted, the intensification-opening interval and the torque excess portion are relatively reduced, as shown in fig. 12.

The embodiments of the present invention are described in detail above, but this does not limit the scope of the claimed invention. Variations and modifications which may occur to those skilled in the art using the basic idea of the invention as defined in the appended claims are also included in the scope of the invention as claimed.