Method for generating virtual internal combustion engine vibrations using a controller in an electric vehicle

Abstract

A method for generating virtual internal combustion engine vibrations using a controller in an electric vehicle, comprising the steps of: collecting driving variable information, determining virtual internal combustion engine vibration characteristics based on the collected driving variable information, determining a vibration torque command having the determined virtual engine vibration characteristics, determining a final motor torque command using a basic motor torque command determined from the collected driving variable information and the determined vibration torque command, and controlling the operation of a vehicle drive motor according to the determined final motor torque command.

Description

Technical Field

[0001] The present disclosure relates to a method for generating a virtual internal combustion engine vibration effect in an electric vehicle. Background Art

[0002] The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.

[0003] As is well known, an electric vehicle (EV) is operated by an electric motor. The drive system of such an electric vehicle includes an electric motor as a vehicle drive source, a battery connected to the electric motor in a rechargeable or dischargeable manner to supply power to drive the electric motor, an inverter connected to the battery to drive and control the electric motor, and a reduction gear that reduces the rotational force and transmits the rotational force to the drive wheels.

[0004] Here, the inverter is used to convert the direct current (DC) supplied by the battery into alternating current (AC), and supply the AC to the electric motor through a power cable during driving the electric motor, and then convert the AC generated by the electric motor into DC to supply to the battery to charge the battery.

[0005] Different from a conventional internal combustion engine vehicle, a multi-stage transmission is not used in a conventional electric vehicle, but a reduction gear with a fixed gear ratio is provided between the electric motor and the drive wheels. This is because in an internal combustion engine (ICE), the distribution range of energy efficiency depends on the operating point and is relatively wide, and high torque is only provided in the high-speed region. In the case of an electric motor, the difference in energy efficiency caused by the operating point is relatively small, and low speed and high torque can be achieved only through the characteristics of the electric motor.

[0006] In addition, for a vehicle equipped with a conventional internal combustion engine drive system, due to the characteristic that the internal combustion engine cannot be driven at low speed, transmission mechanisms such as a torque converter or a clutch are required. However, the electric vehicle drive system may not require such a transmission mechanism because the electric motor can be driven at low speed at any time. Due to this mechanical difference, an electric vehicle can provide smooth driving without interruption of driving performance due to shifting, which is different from an internal combustion engine vehicle.

[0007] Meanwhile, in a vehicle equipped with a conventional internal combustion engine drive system, the main vibration source is the engine (internal combustion engine). The vibration generated by the periodic explosion force of the engine in the starting state is transmitted to the vehicle body and passengers through the drive system or mounting parts. These vibrations are generally considered as negative factors that need to be suppressed. In this regard, since there is no vibration source in an electric vehicle in which the electric motor replaces the engine, the electric vehicle is more advantageous than the internal combustion engine vehicle in terms of improving ride comfort.

[0008] However, for drivers who enjoy driving, the lack of vibration from the engine can make them feel bored. In particular, there is a need for an electric vehicle characterized by aiming for high performance to provide a harsh and trembling effect, rather than just a gentle feeling. However, in the case of adopting a conventional motor control method in an electric vehicle, it may not be possible to provide such an effect to the driver. Summary of the Invention

[0009] The present disclosure provides a method for virtually generating an internal combustion engine (engine) vibration in an electric vehicle as in an internal combustion engine vehicle.

[0010] The present disclosure provides a method for generating virtual internal combustion engine vibration using a controller in an electric vehicle, the method comprising the steps of: collecting driving variable information; determining virtual internal combustion engine vibration characteristics based on the collected driving variable information; determining a vibration torque command having the determined virtual internal combustion engine vibration characteristics; determining a final motor torque command using a basic motor torque command determined from the collected driving variable information and the determined vibration torque command; and controlling the operation of a vehicle drive motor according to the determined final motor torque command.

[0011] According to the present invention, it is possible to virtually generate an internal combustion engine (engine) vibration in an electric vehicle as in an internal combustion engine vehicle, thereby providing a different driving feeling to the driver.

[0012] Furthermore, according to the present disclosure, the characteristics of the virtual internal combustion engine vibration can be adjusted according to driving information such as drive system measurement variables, torque commands, etc. or virtual drive system variables calculated in the electric vehicle, thereby providing a virtual vibration effect with enhanced realism.

[0013] Furthermore, according to the present disclosure, the occurrence of drive system recoil and collision can be suppressed, thereby ensuring the durability of the drive system.

[0014] Based on the description provided herein, further application areas will become apparent. It should be understood that this description and specific examples are for illustrative purposes only and are not intended to limit the scope of the present disclosure. Brief Description of the Drawings

[0015] To better understand the present disclosure, various forms thereof will now be described by way of example with reference to the accompanying drawings, wherein:

[0016] Figure 1 is a block diagram showing one form of a method for generating virtual engine vibration using a virtual engine model according to the present disclosure;

[0017] Figure 2 is a block diagram showing the configuration of an apparatus for performing a virtual engine vibration generation process according to one form of the present disclosure;

[0018] Figure 3 is a flowchart showing a process of generating virtual engine vibrations according to one form of the present disclosure;

[0019] Figure 4 is a diagram showing an example of determining a vibration level based on drive system speed information according to one form of the present disclosure;

[0020] Figure 5 is a diagram showing the vibration level of the drive system speed according to one form of the present disclosure;

[0021] Figure 6 is a diagram showing an example of determining a vibration level based on drive system speed information according to another form of the present disclosure;

[0022] Figure 7 is a diagram showing an example of setting a vibration level according to speed to represent the resonance of a secondary vibration system according to another form of the present disclosure;

[0023] Figure 8 is a diagram showing an example of determining a vibration level based on the drive system torque in the actual driving variable information according to another form of the present disclosure;

[0024] Figure 9 is a diagram showing an example of determining a vibration frequency based on drive system speed information according to another form of the present disclosure; and

[0025] Figure 10 is a diagram showing an example of simultaneously determining and superimposing multiple virtual vibration characteristics to generate virtual internal combustion engine vibrations according to another form of the present disclosure.

[0026] The accompanying drawings described herein are for illustrative purposes only and are not intended to limit the scope of the present disclosure in any way. Detailed Description

[0027] The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or use. It should be understood that in all the drawings, corresponding reference numerals represent similar or corresponding components and features.

[0028] The specific structures or functions described in various forms of the present disclosure are for illustrative purposes only. The present disclosure can be implemented in various forms, and it should be understood that it should not be construed as limited to the various forms described in this specification, but includes all modifications, equivalents, or alternatives included within the spirit and scope of the present disclosure.

[0029] It should be understood that here, although terms such as "first" and "second" can be used to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish elements from each other. For example, without departing from the teachings of the present disclosure, the first element discussed below can be referred to as the second element. Similarly, the second element can also be referred to as the first element.

[0030] It should be understood that when an element is referred to as "coupled" or "connected" to another element, the element can be directly coupled or connected to the other element, or there can be intermediate elements therebetween. In contrast, it should be understood that when an element is referred to as "directly coupled" or "directly connected" to another element, there are no intermediate elements. Other expressions for explaining the relationship between elements, such as "between", "directly between", "adjacent" or "directly adjacent", should be interpreted in the same way.

[0031] Throughout the specification, the same reference numerals denote the same components. At the same time, the terms used herein are only for the purpose of describing a specific form and not for limitation. As used herein, the singular forms "a", "an" and "the" are also intended to include the plural forms unless the context clearly indicates otherwise. It should be further understood that when terms such as "comprises", "comprising", "has" etc. are used in this specification, these terms specify the presence of the stated components, steps, operations and / or elements, but do not preclude the presence or addition of one or more other components, steps, operations and / or their elements.

[0032] Hereinafter, the present disclosure will be described in detail with reference to the accompanying drawings.

[0033] The operations of the methods or algorithms described in connection with the examples disclosed herein can be directly embodied in hardware or software modules executed by a processor, or in a combination thereof. The software modules can reside on a storage medium (i.e., a memory and / or a storage device), such as a RAM, a flash memory, a ROM, an EPROM, an EEPROM, a register, a hard disk, a removable disk, and a CD-ROM.

[0034] The present disclosure relates to a method of realistically generating virtual internal combustion engine (engine) vibrations in an electric vehicle using a drive motor. Specifically, the present disclosure includes a method of determining the amplitude and period of virtual internal combustion engine vibrations in order to generate virtual internal combustion engine vibrations.

[0035] According to the present disclosure, in an electric vehicle without an internal combustion engine (engine), virtual internal combustion engine vibrations are achieved by generating a torque for simulating the vibration characteristics of an internal combustion engine vehicle through a drive motor.

[0036] Figure 1The principle and method of generating vibrations of an internal combustion engine (engine) using a virtual engine model according to the present invention are shown. In the following description, the electric motor for generating virtual internal combustion engine vibrations is a drive motor connected to a drive wheel to drive a vehicle. In addition, those of ordinary skill in the art will understand that in the following description, the internal combustion engine and the engine can be used interchangeably.

[0037] According to the present disclosure, actual driving variable information for implementing virtual internal combustion engine vibrations during driving an electric vehicle is collected in real time, and a vibration torque command having virtual vibration characteristics of an internal combustion engine vehicle can be determined based on information of the input variables of the virtual internal combustion engine model in Figure 1 . Alternatively, after determining virtual state variable information in the virtual internal combustion engine (engine) model based on the collected actual driving variable information, a vibration torque command having vibration characteristics of an internal combustion engine vehicle to be implemented can be determined according to the determined virtual state variable information. Otherwise, both the actual driving variable information and the virtual state variable information can be used to determine the vibration torque command.

[0038] Here, the driving variable information is information about the actual system of the electric vehicle, which can be real-time vehicle driving information in the electric vehicle. In addition, the vehicle driving information can include driver input information and driving state information in the electric vehicle.

[0039] The vehicle driving information can be sensor information detected by sensors and input via a vehicle network, information determined by a controller of a virtual engine vibration generator according to the present disclosure, or information input from another controller in the vehicle to the controller of the virtual engine vibration generator.

[0040] Specifically, among the items of driving variable information, the driver input information can be a driver pedal input value, and the driver pedal input value can be an accelerator pedal input value and a brake pedal input value. Here, the accelerator pedal input value (APS value) is obtained by the driver operating the accelerator pedal and can be information detected by an accelerator pedal detector (APS), as described below. In addition, the brake pedal input value (BPS value) is obtained by the driver operating the brake pedal and can be information detected by a brake pedal detector (BPS), as described below.

[0041] Among the items of driving variable information, the driving state information can include motor torque and drive system speed. Here, the motor torque can be a motor torque command determined by a controller based on vehicle driving information collected from the vehicle. More specifically, the motor torque can be a basic motor torque command determined and generated by a basic torque command generation unit ( Figure 2 the reference numeral “21” in

[0042] A basic motor torque command can be determined based on driving variable information, and methods and processes for determining and generating a basic motor torque command for controlling the torque output of a drive motor in an electric vehicle are known in the related art and will not be described in detail herein.

[0043] The drive system speed may include the motor speed, which is the actual motor speed measured by a speed detector. Here, the speed detector may be a resolver installed on the drive motor, as described below. Additionally, the drive system speed may include the drive wheel speed, and in this case, the speed detector may be a wheel speed sensor installed on the drive wheel. Moreover, the drive system speed may include the drive shaft speed. As described above, the drive system speed in the present disclosure may be defined as the rotational speed at any position of a vehicle drive system including a motor, a reducer, a drive shaft, and drive wheels.

[0044] Furthermore, in one form of the present disclosure, the vibration torque command may be determined as a function of the actual drive variables as described above, the vibration torque command may be determined as a function of the virtual state variables in an internal combustion engine determined from the actual driving variable values, or the vibration torque command may be determined as a function of the actual drive variables and the virtual state variables.

[0045] In one form of the present disclosure, a preset virtual internal combustion engine model may be used to obtain the virtual state variable values in an internal combustion engine from the actual driving variable values in an electric vehicle.

[0046] In one form of the present disclosure, when using a virtual internal combustion engine model including a virtual engine and a virtual transmission, the virtual engine speed becomes the input speed of the virtual transmission. This virtual engine speed can be calculated as a variable multiple of the drive system speed detected by the speed detector, where the drive system speed may be the motor speed. In this case, the coefficient value multiplied by the motor speed to calculate the virtual engine speed may be a value determined according to the virtual transmission and gear ratio model and the virtual current gear.

[0047] In an electric vehicle without a multi-stage transmission, a control method for generating a virtual transmission feeling for the electric vehicle is known, such that a multi-stage speed change feeling can be generated and realized through the torque control of the drive motor. Additionally, it is known that in the control process for generating a virtual transmission feeling for an electric vehicle, the virtual engine speed is used as one of the virtual state variables to generate and realize the multi-stage speed change feeling.

[0048] Therefore, according to the present invention, the virtual engine speed, as one of the virtual state variables for generating and realizing the multi-stage speed change feeling, can be used as the virtual state variable for generating virtual internal combustion engine vibrations. In one form of the present disclosure, the virtual vibration controller may use the virtual vehicle speed and the virtual current gear ratio information to determine the virtual engine speed.

[0049] Here, by using a virtual final reduction ratio and an actual motor speed as one of the actual driving variables, a virtual vehicle speed can be calculated as a value proportional to the actual motor speed, where the virtual final reduction ratio is a value preset in a virtual vibration controller. In one form of the present disclosure, the actual motor speed measured during vehicle driving and the virtual final reduction ratio can be used to calculate the virtual vehicle speed, and the virtual engine speed can be calculated in real time based on the virtual vehicle speed.

[0050] In this case, the virtual engine speed can be obtained based on the value obtained by multiplying the virtual vehicle speed by the virtual gear ratio of the virtual current gear, or the virtual engine speed can be obtained based on the value obtained by multiplying the drive system speed (such as the motor speed) by the virtual gear ratio of the virtual current gear.

[0051] In addition, the virtual current gear stage can be determined from the virtual vehicle speed and the accelerator pedal input value (APS value) according to a transmission schedule map preset in the virtual vibration controller. When the virtual current gear stage is determined as described above, the virtual engine speed can be calculated in real time using the virtual gear ratio corresponding to the gear stage and the virtual vehicle speed or the motor speed.

[0052] The virtual state variables determined by inputting the driving variables into a virtual internal combustion engine (engine) model are used alone or together with the driving variables to determine a vibration torque command. When generating the vibration torque command, after determining the virtual vibration characteristics, a final vibration torque command with the determined virtual vibration characteristics is determined. Here, the virtual vibration characteristics can include a vibration frequency and a vibration level (or amplitude).

[0053] Subsequently, the vibration torque command determined as described above is added to the original motor torque command, and then the operation of the motor is controlled according to the added final motor torque command to generate torque through the motor. As a result, a virtual vibration such as an actual internal combustion engine vibration can be generated.

[0054] In one form of the present disclosure, the vibration torque command becomes a correction torque command for generating a virtual internal combustion engine vibration. In addition, the original motor torque command is a command corresponding to the driver-requested torque determined according to the driver's driving input value, that is, a basic motor torque command, which becomes the motor torque command before correction. In addition, in the present disclosure, correcting the original motor torque command can mean adding the vibration torque command to the original motor torque command. At this time, the added final motor torque command becomes the corrected motor torque command.

[0055] Hereinafter, a method of generating a virtual vibration according to one form of the present disclosure will be described in more detail with reference to the following drawings.

[0056] Figure 2 is a block diagram showing a configuration of an apparatus for performing a virtual engine vibration generation process according to one form of the present disclosure, Figure 3 is a flowchart showing a process of generating virtual engine vibration according to one form of the present disclosure.

[0057] As Figure 2 shown, the apparatus for performing the virtual internal combustion engine vibration generation process includes: a driving information detector 12 that detects vehicle driving information (which is driving variable information), a first controller 20 that generates and outputs a torque command based on the vehicle driving information detected by the driving information detector 12, and a second controller 30 that controls the operation of a driving device 41 according to the torque command output from the first controller 20.

[0058] In addition, the apparatus for performing the virtual internal combustion engine vibration generation process may further include an interface unit 11 that is configured to allow a driver to selectively input to turn on or off the virtual internal combustion engine vibration generation function.

[0059] Although the controllers are shown as being divided into the first controller 20 and the second controller 30, the vibration generation control process and the vehicle driving control process may be performed by a single integrated controller instead of by multiple controllers.

[0060] The single integrated controller and the separate controllers may be collectively referred to as a controller, and the control process for generating virtual internal combustion engine vibration as described below may be performed by this controller. For example, the first controller 20 and the second controller 30 in the form described later may be collectively referred to as a controller.

[0061] The interface unit 11 may be any type of interface unit as long as it has a function that enables a driver to manipulate to turn on and off the function of generating virtual internal combustion engine vibration in a vehicle. For example, the interface unit may be an operating device such as a button or a switch provided in the vehicle, or an input device or a touch screen of an audio, video, navigation (AVN) system.

[0062] The interface unit 11 may be connected to the first controller 20, and more specifically, to a virtual vibration control unit 22 in the first controller 20, which will be described below. Therefore, when the driver manipulates a turn-on or turn-off operation through the interface unit 11, an on or off signal from the interface unit 11 may be input to the virtual vibration control unit 22 of the first controller 20. As a result, the virtual vibration control unit 22 of the first controller 20 can recognize the on or off operation state of the driver with respect to the virtual internal combustion engine vibration generation function (see Figure 3 step S1 in).

[0063] In the present disclosure, the function of generating virtual internal combustion engine vibrations during vehicle driving is executed only when the driver inputs an activation operation through the interface unit 11. Additionally, the interface unit 11 may be an in-vehicle input device provided in the vehicle, or the interface unit may be a mobile device through which the driver can input the activation / deactivation operation of the virtual internal combustion engine vibration generation function. The mobile device needs to be communicatively connected to an in-vehicle device, such as the first controller 20, and for this purpose, an input / output communication interface for communicating between the mobile device and the first controller 20 is used.

[0064] The driving information detector 12 is a unit that detects vehicle driving information (driving variable information) to execute the virtual internal combustion engine vibration generation function and detects vehicle driving information (driving variable information) to generate a basic motor torque command in the vehicle. In one form of the present disclosure, the driving information detector 12 includes an accelerator pedal detection unit that detects accelerator pedal input information (accelerator pedal input value) based on the driver's accelerator pedal operation, a brake pedal detection unit that detects brake pedal input information (brake pedal input value) based on the driver's brake pedal operation, and a speed detection unit that detects the speed of the vehicle drive system.

[0065] Here, the accelerator pedal detection unit may be a conventional accelerator pedal position sensor (APS) installed on the accelerator pedal to output an electrical signal based on the driver's accelerator pedal operation state. The brake pedal detection unit may be a conventional brake pedal sensor (BPS) installed on the brake pedal to output an electrical signal based on the driver's brake pedal operation state.

[0066] The speed detection unit is provided to obtain the speed information of the vehicle drive system, where the speed information of the vehicle drive system may include the motor speed, i.e., the rotational speed of the drive motor 41. In this case, the speed detection unit may be a resolver installed on the drive motor 41. Alternatively, the speed information of the vehicle drive system may include the rotational speed of the drive wheels 43 (drive wheel speed), and in this case, the speed detection unit may be a wheel speed sensor installed on the drive wheels 43. Alternatively, the speed information of the vehicle drive system may include the rotational speed of the drive shaft (drive shaft speed), and in this case, the speed detection unit may be a sensor capable of detecting the rotational speed of the drive shaft.

[0067] In addition, the first controller 20 may include: a basic torque command generation unit 21 that determines and generates a basic motor torque command from vehicle driving information; a virtual vibration control unit 22 that determines and generates a correction torque command (i.e., a vibration torque command) using one or both of an actual drive variable and a virtual state variable to generate motor vibration for virtual internal combustion engine vibration; and a final torque command generation unit 23 that generates a corrected final motor torque command by correcting the basic motor torque command using the corrected torque command.

[0068] The basic motor torque command is a motor torque command determined and generated based on vehicle driving information collected during driving of a conventional electric vehicle, and the basic torque command generation unit 21 may be a vehicle control unit (VCU) or a part thereof that generates a motor torque command based on vehicle driving information of a conventional electric vehicle.

[0069] In addition, the virtual vibration control unit 22 is a novel component that determines, generates, and outputs a vibration torque command in addition to the basic motor torque command according to the present disclosure. The vibration torque command is a correction torque command used only to achieve virtual internal combustion engine vibration. The virtual vibration control unit may be added to the vehicle controller as a part of the vehicle controller, or may be provided as a control element independent of the vehicle controller.

[0070] In one form of the present disclosure, the virtual vibration control unit 22 is a control element that performs overall control for achieving virtual internal combustion engine vibration, and obtains virtual state variable information (see step S2 in Figure 3 ) in an internal combustion engine (virtual internal combustion engine model) based on variables and actual drive variables (such as drive system speed) in the electric vehicle.

[0071] In addition, the virtual vibration control unit 22 uses one or both of the actual drive variable and the virtual state variable to determine the virtual vibration characteristics (see step S3 in Figure 3 ), and determines and generates a final correction torque command (vibration torque command) for generating virtual internal combustion engine vibration according to the determined virtual vibration characteristic information.

[0072] In the final torque command generation unit 23, the basic motor torque command input from the basic torque command generation unit 21 is corrected by the correction torque command input from the virtual vibration control unit 22, and the final motor torque command may be calculated by adding the corrected vibration torque command and the basic motor torque command.

[0073] The second controller 30 receives the torque command transmitted from the first controller 20, i.e., the final motor torque command determined by the final torque command generation unit 23 of the first controller 20, so as to control the operation of the drive device 41. Here, the drive device 41 is a drive motor 41 that is connected to the drive wheel 43 to drive the vehicle. At this time, the second controller 30 can be a known motor control unit (MCU), which drives the drive motor 41 through an inverter and controls the drive of the drive motor 41 in a conventional electric vehicle.

[0074] In one form of the present disclosure, a vibration torque command for generating virtual internal combustion engine vibration is used to transfer the virtual internal combustion engine vibration to the torque of the motor, so as to generate a slight tremor of the motor torque that matches the virtual vibration characteristics. The command value of the vibration torque command can fluctuate in a waveform having a predetermined frequency (or period) and amplitude (vibration amplitude). That is, the command value of the vibration torque command can be associated with the virtual vibration characteristics, and for example, can correspond to the vibration frequency (or period) and amplitude (vibration amplitude) in the virtual vibration characteristics.

[0075] In one form of the present disclosure, the torque and rotational force output by the motor as the drive device 41 are reduced by the speed reducer 42 and then transmitted to the drive wheel 43, as Figure 2 shown. When controlling the drive of the motor 41 according to the final motor torque command corrected by the vibration torque command as described above, the motor torque is output together with the virtual internal combustion engine vibration.

[0076] In Figure 3 it, after determining the final motor torque command by correcting the basic motor torque command according to the vibration torque command having virtual vibration characteristics, it is checked in step S4 whether the motor state is in a normal operating state, the gear transmission state is checked in step S5, and then the drive of the motor 41 is controlled according to the final motor torque command in step S6, so as to provide a vibration effect.

[0077] Meanwhile, in the virtual vibration control unit 22 of the first controller 20, the virtual vibration characteristics can be determined by using the actual drive variables and virtual state variables as described above. For example, the virtual vibration characteristics are determined based on the motor torque and motor speed, and the vibration torque command for generating the virtual internal combustion engine vibration is determined according to the determined virtual vibration characteristics.

[0078] Figure 4 is a diagram showing a state of generating a final motor torque command for realizing virtual internal combustion engine vibration based on the vibration amplitude determined according to the drive system speed information according to one form of the present disclosure. As Figure 4As shown, when determining the basic motor torque command and detecting the motor speed in real time, the vibration amplitude in the virtual vibration characteristics can be determined based on the detected motor speed. Subsequently, when determining the vibration torque command with the determined vibration amplitude, the final motor torque command can be determined by correcting the basic motor torque command with the vibration torque command. At this time, the final motor torque command can be determined as the value obtained by adding the vibration torque command to the basic motor torque command.

[0079] In Figure 4 form, the vibration amplitude in the virtual vibration characteristics is determined based on the motor speed as the drive system speed, and the motor speed can be replaced by the vehicle speed or the virtual engine speed as the virtual drive system speed. Here, the vehicle speed can be the actual vehicle speed detected by a sensor, or a virtual vehicle speed calculated as being proportional to the actual motor speed (actual drive system speed) by using the actual motor speed (actual drive system speed) and the virtual final reduction ratio, as described above. Since the vehicle speed is also related to the drive system speed (e.g., motor speed), according to the present disclosure, the vehicle speed can be used as the speed information for realizing the virtual internal combustion engine vibration.

[0080] Figure 5 The vibration amplitude according to the drive system speed information is shown, where the drive system speed can be: the actual motor speed, i.e., the actual drive system speed, or the virtual engine speed, i.e., the virtual drive system speed, or the vehicle speed, as described above.

[0081] In addition, as will be described later, it is possible to set to determine the vibration amplitude by using the drive system speed and drive system torque (motor torque, APS value, etc.) information (refer to the description regarding Figure 10 ). That is, both the vibration amplitude determined based on the actual motor speed and the vibration amplitude determined based on the motor torque command can be used to generate the vibration torque command.

[0082] In one form of the present disclosure, as the drive system speed increases, the vibration amplitude can be determined to be a smaller value. In order to determine the vibration amplitude as the virtual vibration characteristics based on the drive system speed information, the setting information defining the correlation between the limit speed and the vibration amplitude can be input and stored in the controller in advance. Here, the setting information can be a map, graph, or function formula capable of determining the vibration amplitude using the speed as an input.

[0083] Referring to Figure 5, which shows a graph in which the vibration amplitude is set to a value corresponding to the speed, and it can be seen that the higher the speed, the smaller the set vibration amplitude. Using this graph, the vibration amplitude according to the current drive system speed (motor speed) can be determined. In addition, when the virtual engine speed is in the idle state or when the vehicle speed is in the stationary state, the engine idle vibration can be virtually generated by setting the vibration amplitude to the set maximum value.

[0084] Figure 6 is a graph showing the state of generating a final motor torque command for realizing virtual internal combustion engine vibration based on the vibration amplitude determined according to the drive system speed information according to another form of the present disclosure. In Figure 6 the form, as in Figure 4 the form, when the basic motor torque command is determined and the motor speed is detected in real time, the vibration amplitude in the virtual vibration characteristics can be determined according to the detected motor speed. Subsequently, when the vibration torque command with the determined vibration amplitude is determined, the final motor torque command can be determined by correcting the basic motor torque command with the vibration torque command. At this time, the final motor torque command can be determined as the value obtained by adding the vibration torque command to the basic motor torque command.

[0085] In Figure 6 the form, the vibration amplitude is determined to represent the resonance of the secondary vibration system. Generally, the amplitude (vibration amplitude) increases at the speed within the resonance region and then decreases as the speed leaves the resonance region. In view of this phenomenon, when the drive system speed (the above actual speed or virtual speed) is within a predetermined region, the vibration amplitude can be increased to a set value and then decreased.

[0086] Figure 7 is a graph showing an example of setting the vibration amplitude according to the speed to represent the resonance of the secondary vibration system according to one form of the present disclosure. In Figure 7 it, the speed can be the virtual engine speed. As Figure 7 shown, when the virtual engine speed is within the first region set to a relatively low (small) speed range, the vibration amplitude can be set to rapidly increase to the first set value and then decrease. In addition, when the virtual engine speed is within the second region set to a relatively high (large) speed range, the vibration amplitude can be set to rapidly increase to the second set value and then decrease.

[0087] In this case, the first region can be set as the idle region of the internal combustion engine, and the second region can be set as the speed region where the secondary natural vibration occurs. In addition, the first set value and the second set value can be the same or different values. Therefore, when the virtual engine speed is in the idle region, the first natural vibration can be generated, and as the virtual engine speed increases, the effect corresponding to the second natural vibration can also be generated.

[0088] Referring again to Figure 6 , as in the example of Figure 7 , when the vibration amplitude representing the resonance of the secondary vibration system is determined, a vibration torque command having the determined vibration amplitude can be determined, and then the final motor torque command can be determined by correcting the basic motor torque command with the vibration torque command. At this time, the final motor torque command can be determined as a value obtained by adding the vibration torque command to the basic motor torque command.

[0089] In Figure 7 , in addition to the virtual engine speed, this speed can also be the motor speed, that is, the drive system speed, or the vehicle speed. Here, the vehicle speed can be the actual vehicle speed detected by the speed detection unit, or can be a virtual vehicle speed calculated as being proportional to the actual motor speed by using the actual motor speed and the virtual final reduction ratio as described above.

[0090] Figure 8 is a diagram showing a state of generating a final motor torque command for realizing virtual internal combustion engine vibration based on the vibration amplitude determined according to the drive system torque in another form according to the present disclosure. As shown, when determining the virtual vibration characteristics of the vibration torque command for realizing virtual internal combustion engine vibration, the vibration amplitude in the virtual vibration characteristics can be determined based on the drive system torque.

[0091] Here, the drive system torque can be the motor torque or the motor torque command. Specifically, the motor torque can be the basic motor torque command generated by the basic torque command generation unit 22. In addition, the motor torque can be replaced by the accelerator pedal input value (APS value). In other words, the vibration amplitude as the virtual vibration characteristics can be determined based on the accelerator pedal input value. In addition, the motor torque can be replaced by the load value.

[0092] Generally, as the internal combustion engine load increases, the fuel injection amount and the explosion force increase, and the vibration transmitted to the vehicle body may also increase. In order to virtually generate this vibration effect, when the motor torque or the load value corresponding to the command or the accelerator pedal input value is large, the vibration amplitude as the virtual vibration characteristics can be set to a large value. In addition, since there is no fuel injection or explosion during the engine braking operation, in order to represent a smaller vibration effect, when the motor torque is zero or the regeneration torque is a negative torque, the vibration amplitude can be set to a smaller value.

[0093] Figure 9This is a diagram showing a state in which, according to one form of the present disclosure, after determining virtual vibration characteristics based on drive system speed information, a final motor torque command for implementing virtual internal combustion engine vibration is generated based on the vibration frequency in the virtual vibration characteristics. The vibration frequency (or period) is a fundamental element for generating more realistic virtual vibration. In the present disclosure, the vibration frequency of the virtual vibration characteristics can be determined based on the drive system speed, which is actual driving variable information.

[0094] Here, the drive system speed, which is the actual driving variable information for determining the vibration frequency, can be the actual motor speed detected by a speed detection unit. At this time, the motor speed can be replaced by the vehicle speed. Alternatively, the vibration frequency can be determined based on the virtual engine speed, which is virtual drive system speed information. The vehicle speed can be the actual vehicle speed (actual driving variable information) detected by the speed detection unit, or a virtual vehicle speed (virtual state variable) calculated as being proportional to the actual motor speed by using the actual motor speed and the virtual final reduction gear ratio as described above. Since the vehicle speed is also related to the drive system speed (e.g., motor speed), according to the present disclosure, the vehicle speed can be used as the speed information for implementing virtual internal combustion engine vibration.

[0095] Since the vibration of the internal combustion engine increases (more rapidly) as the rotational speed (rpm) increases, the vibration frequency in the virtual vibration characteristics can also be determined to have a larger value as the actual drive system speed or the virtual drive system speed increases. That is, as Figure 9 shown, as the motor speed increases, the vibration frequency can increase proportionally.

[0096] In addition, as Figure 9 shown, when determining the basic motor torque command and detecting the motor speed in real time, the vibration frequency in the virtual vibration characteristics can be determined based on the detected motor speed. Subsequently, when determining the vibration torque command having the determined vibration frequency, the final motor torque command can be determined by correcting the basic motor torque command with the vibration torque command. At this time, the final motor torque command can be determined as a value obtained by adding the vibration torque command to the basic motor torque command.

[0097] Next, Figure 10 This is a diagram illustrating another method of determining virtual vibration characteristics according to the present disclosure, in which multiple virtual vibration characteristics can be determined and applied simultaneously. That is, for example, the vibration amplitude in the virtual vibration characteristics can be determined by simultaneously using the drive system speed (e.g., actual motor speed or virtual engine speed) and the drive system torque (e.g., basic motor torque command or accelerator pedal input value).

[0098] For example, as described above, after determining the vibration amplitude based on the drive system speed and determining the vibration amplitude based on the drive system torque, the final vibration amplitude can be determined based on the vibration amplitude based on the drive system speed and the torque amplitude based on the drive system torque. In this case, the final vibration amplitude can be determined by multiplying the vibration amplitude based on the drive system speed by the vibration amplitude based on the drive system torque.

[0099] In this case, the vibration frequency can be determined by the drive system speed, as Figure 9 described. For example, the vibration frequency can be determined based on the motor speed, and the greater the motor speed, the greater the vibration frequency that can be determined.

[0100] When determining the vibration amplitude based on the drive system speed and the drive system torque, the drive system speed can be the actual drive system speed detected by the speed detection unit, or a virtual drive system speed determined based on the actual drive system speed, or the vehicle speed, as described above. In addition, the drive system torque can be the basic motor torque command as the motor torque or the accelerator pedal input value (APS value).

[0101] Therefore, when the vibration amplitude and the vibration frequency are determined as described above, a vibration torque command with the determined vibration amplitude and vibration frequency can be determined, and then the final motor torque command can be determined by correcting the basic motor torque command with the vibration torque command. At this time, the final motor torque command can be determined as the value obtained by adding the vibration torque command and the basic motor torque command.

[0102] In this way, after determining the vibration torque command using multiple virtual vibration characteristics, the basic motor torque command and the vibration torque command can be used to determine and generate the final motor torque command, and then the operation of the drive motor can be controlled according to the generated final motor torque command, so that the drive motor can generate virtual internal combustion engine vibration.

[0103] Although various forms of the present disclosure have been described in detail, the scope of the present disclosure is not limited to the above forms, and various modifications and changes made by those skilled in the art using the basic concepts of the present disclosure defined in the following claims are also included in the scope of the present disclosure.

Claims

1. A method for a controller to generate virtual internal combustion engine vibrations in an electric vehicle, the method comprises the following steps: Collect driving variable information; Determine virtual internal combustion engine vibration characteristics based on the collected driving variable information; Determine a vibration torque command having the determined virtual internal combustion engine vibration characteristics; Use a basic motor torque command determined from the collected driving variable information and the determined vibration torque command to determine a final motor torque command; And Control the operation of the vehicle drive motor according to the determined final motor torque command; wherein, the determined vibration torque command is added to the basic motor torque command, and then the operation of the motor is controlled according to the added final motor torque command to generate torque through the motor, so that virtual internal combustion engine vibrations as actual internal combustion engine vibrations are generated in the electric vehicle, wherein, when determining the virtual internal combustion engine vibration characteristics, the driving variable information for determining the virtual internal combustion engine vibration characteristics includes a virtual drive system speed determined from an actual drive system speed, wherein, the actual drive system speed is a motor speed, the virtual drive system speed is a virtual engine speed, and a coefficient value multiplied by the motor speed to calculate the virtual engine speed is a value determined according to a virtual transmission and gear ratio model and a virtual current gear position.

2. The method according to claim 1, wherein, the virtual internal combustion engine vibration characteristics include a vibration frequency and a vibration amplitude.

3. The method according to claim 1, wherein, the virtual engine speed is determined as a multiple value of the actual drive system speed.

4. The method according to claim 1, wherein, the virtual internal combustion engine vibration characteristics include a vibration amplitude, and wherein, when determining the virtual internal combustion engine vibration characteristics, the vibration amplitude is determined to become smaller as the actual drive system speed, the virtual drive system speed or the vehicle speed becomes larger.

5. The method according to claim 1, wherein, the virtual internal combustion engine vibration characteristics include a vibration frequency, and when determining the virtual internal combustion engine vibration characteristics, the vibration frequency is determined to become larger as the actual drive system speed, the virtual drive system speed or the vehicle speed becomes larger.

6. The method according to claim 1, wherein, the virtual internal combustion engine vibration characteristics include a vibration amplitude, and when determining the virtual internal combustion engine vibration characteristics, when the actual drive system speed, the virtual drive system speed or the vehicle speed is within a predetermined region, the vibration amplitude is determined to first increase to a set value and then decrease.

7. The method according to claim 6, the method further comprises: As the actual drive system speed or the virtual drive system speed increases, the controller generates an effect corresponding to secondary natural vibration, wherein, when determining the virtual internal combustion engine vibration characteristics, when the actual drive system speed or the virtual drive system speed is within a first region defined as a relatively low speed range, the vibration amplitude is determined to first increase to a first predetermined set value and then decrease, and When the actual drive system speed or the virtual drive system speed is within a second region defined as a speed range higher than the first region, the vibration amplitude is determined to first increase to a second predetermined set value and then decrease.

8. The method according to claim 7, wherein, the first region is the idling region of the internal combustion engine.

9. The method according to claim 1, wherein, the vehicle speed is the actual vehicle speed detected by a sensor or the virtual vehicle speed obtained from the actual drive system speed.

10. The method according to claim 1, wherein, when determining the virtual internal combustion engine vibration characteristics, the driving variable information includes one selected from the accelerator pedal input value determined based on the driver's accelerator pedal operation and the basic motor torque command.

11. The method according to claim 10, wherein, the virtual internal combustion engine vibration characteristics include the vibration amplitude, and when determining the virtual internal combustion engine vibration characteristics, the vibration amplitude is determined to increase as the accelerator pedal input value or the basic motor torque command increases.

12. The method according to claim 10, wherein, the virtual internal combustion engine vibration characteristics include the vibration frequency, and when determining the virtual internal combustion engine vibration characteristics, the vibration frequency is determined to increase as the accelerator pedal input value or the basic motor torque command increases.

13. The method according to claim 1, wherein, when determining the virtual internal combustion engine vibration characteristics, the driving variable information further includes: information of one selected from the accelerator pedal input value determined based on the driver's accelerator pedal operation and the basic motor torque command, and wherein the virtual internal combustion engine vibration characteristics include the vibration frequency and the vibration amplitude.

14. The method according to claim 13, wherein, when determining the virtual internal combustion engine vibration characteristics, the final vibration amplitude is determined by multiplying the vibration amplitude determined from the selected speed information by the vibration amplitude determined from the accelerator pedal input value or the basic motor torque command, and the vibration frequency is determined according to the selected speed information, the accelerator pedal input value or the basic motor torque command.

15. The method according to claim 13, wherein, the virtual engine speed is determined to be a multiple value of the actual drive system speed.

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