Electric vehicles

Abstract

To provide a function which relates to technology that generates an artificial sound in an electric vehicle that changes in response to a driving condition, and which enables a driver to enjoy an artificial sound more than before.SOLUTION: An electric vehicle includes one or more processors constituted to generate an artificial sound that changes in response to the driving condition of the electric vehicle and output the artificial sound from a speaker mounted to the electric vehicle. The one or more processors further recognize the travel state of other vehicles traveling in the surround of the electric vehicle, and executes at least one of a first processing and a second processing in response to the recognized travel state of the other vehicles. The first processing involves changing the sound source of the artificial sound. The second processing involves generating a harmonious sound that harmonizes with the artificial sound and outputting the harmonious sound from the speaker superimposing it on the artificial sound.SELECTED DRAWING: Figure 5

Description

Technical Field

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[0001] The present disclosure relates to an electric vehicle having an electric motor as a drive source.

Background Art

[0002] Patent Document 1 discloses a sound control device mounted on an electric vehicle. The sound control device disclosed in Patent Document 1 controls a pseudo engine sound so as to realistically represent the engine sound generated when shifting gears in an engine vehicle.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Since an electric motor has a small driving sound, a driver who drives an electric vehicle usually has few opportunities to feel the driving state of the electric vehicle by sound. Therefore, by generating an artificial sound that changes in response to the driving state of an electric vehicle, such as a pseudo engine sound, it becomes possible for the driver to enjoy driving the electric vehicle by sound. For example, the pseudo engine sound can give the driver a sense of presence as if driving an engine vehicle.

[0005] By providing a function that allows the driver to more enjoy such an artificial sound, it is possible to improve the user's satisfaction. One of the things that the driver enjoys is considered to be the change in the artificial sound related to the running of the electric vehicle. As an element related to the running of the electric vehicle, there is a change in the running situation of other vehicles running around the electric vehicle. One object of the present disclosure is to provide a function that allows the driver to more enjoy an artificial sound by focusing on the change in the running situation of other vehicles running around the electric vehicle. [Means for solving the problem]

[0006] One aspect of this disclosure relates to an electric vehicle having an electric motor as a power source. The electric vehicle includes one or more processors configured to generate artificial sounds that change in response to the driving state of the electric vehicle and to output the artificial sounds from a speaker mounted on the electric vehicle. The one or more processors further recognize the driving conditions of other vehicles traveling around the electric vehicle and perform at least one of the following first and second processes in response to the recognized driving conditions of other vehicles. The first process is a process of changing the sound source of the artificial sound. The second process is a process of generating a harmonic sound that harmonizes with the artificial sound and superimposing the harmonic sound on the artificial sound and outputting it from the speaker. [Effects of the Invention]

[0007] According to this disclosure, by executing the first and second processes in response to the driving conditions of other vehicles, changes in the driving conditions of other vehicles can be reflected in changes in the artificial sound output from the speaker. This provides a function that allows drivers to enjoy the artificial sound more. As a result, user satisfaction of electric vehicles can be improved. [Brief explanation of the drawing]

[0008] [Figure 1] This is a conceptual diagram showing an electric vehicle and vehicle management system according to an embodiment. [Figure 2] This is a conceptual diagram illustrating an example of the basic functional configuration of a vehicle management system. [Figure 3] This is a conceptual diagram illustrating the overview of the sound source change function. [Figure 4] This is a conceptual diagram illustrating the overview of the harmonic sound output function. [Figure 5] This diagram shows the functional configuration of the vehicle management system related to the sound source change function and the processing flow of the processes executed by the vehicle management system. [Figure 6]This diagram shows the functional configuration of the vehicle management system related to the harmonic sound output function and the processing flow of the processes performed by the vehicle management system. [Figure 7] This is a block diagram showing an example configuration of a power control system for an electric vehicle. [Modes for carrying out the invention]

[0009] Embodiments of this disclosure will be described with reference to the attached drawings.

[0010] 1. Electric vehicles and vehicle management systems Figure 1 is a conceptual diagram showing an electric vehicle 10 and a vehicle management system 100 according to this embodiment. The electric vehicle 10 has an electric motor 44 as a drive source. Examples of the electric motor 44 include a brushless DC motor and a three-phase AC synchronous motor. The electric vehicle 10 uses the electric motor 44 as a power device for driving.

[0011] Furthermore, the electric vehicle 10 is equipped with various sensors 11. These sensors 11 detect the driving state of the electric vehicle 10. Examples of the sensors 11 include an accelerator position sensor, a brake position sensor, a steering angle sensor, a steering torque sensor, a wheel speed sensor, an acceleration sensor, a rotational speed sensor, a position sensor, and a recognition sensor. The accelerator position sensor detects the amount of operation of the accelerator pedal. The brake position sensor detects the amount of operation of the brake pedal. The steering angle sensor detects the steering angle of the steering wheel. The steering torque sensor detects the steering torque of the steering wheel. The wheel speed sensor detects the rotational speed of the wheels of the electric vehicle 10. The acceleration sensor detects the lateral and longitudinal acceleration of the electric vehicle 10. The rotational speed sensor detects the rotational speed of the electric motor 44. The position sensor detects the position of the electric vehicle 10. An example of a position sensor is a GNSS (Global Navigation Satellite System) sensor. The recognition sensor is a sensor for recognizing (detecting) the surrounding conditions of the electric vehicle 10. Examples of recognition sensors include cameras, LiDAR (Light Detection and Ranging), radar, and others.

[0012] Furthermore, the electric vehicle 10 is equipped with one or more speakers 70. For example, the speaker 70 is an in-vehicle speaker that outputs sound into the cabin of the electric vehicle 10. In other examples, the speaker 70 may be an external speaker that outputs sound outside the electric vehicle 10. The electric vehicle 10 may have both in-vehicle speakers and external speakers.

[0013] Furthermore, the electric vehicle 10 is equipped with a human-machine interface (HMI) 12 as an interface with the user. The HMI 12 presents various information to the user through display and sound, and also accepts various inputs from the user. The HMI 12 consists of a display (e.g., multi-information display, meter display), switches, speakerphone, touch panel, etc. The speaker 70 may also be configured as part of the HMI 12.

[0014] Furthermore, the electric vehicle 10 is equipped with a communication device 13 that communicates with external devices to send and receive information. Examples of the communication device 13 include a device that connects to the internet to send and receive information with various servers, a device that communicates with infrastructure facilities to send and receive infrastructure information, and a device that communicates with surrounding vehicles to send and receive information about other vehicles.

[0015] The vehicle management system 100 is applied to such an electric vehicle 10 and manages the electric vehicle 10. The entire vehicle management system 100 may be installed in the electric vehicle 10. As another example, at least a part of the vehicle management system 100 may be contained in an external management server outside the electric vehicle 10. In that case, the vehicle management system 100 may manage the electric vehicle 10 remotely. As yet another example, the vehicle management system 100 may be distributed between the electric vehicle 10 and the management server.

[0016] Generally speaking, the vehicle management system 100 includes one or more processors 101 (hereinafter simply referred to as the processor 101) and one or more storage devices 102 (hereinafter simply referred to as the storage device 102). The processor 101 executes various processes. The processor 101 is composed of a general-purpose processor, a special-purpose processor, a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), an integrated circuit, a conventional circuit, etc. The processor 101 can also be referred to as circuitry or processing circuitry. Circuitry is hardware programmed to realize the described functions, or hardware that executes functions. The storage device 102 stores (stores) various information. Examples of the storage device 102 include a volatile memory, a non-volatile memory, an HDD (Hard Disk Drive), an SSD (Solid State Drive), etc. Through the cooperation of the processor 101 and the storage device 102, the functions of the vehicle management system 100 are realized.

[0017] One or more vehicle management programs 105 (hereinafter simply referred to as the vehicle management program 105) are computer programs executed by the processor 101. The functions of the vehicle management system 100 may be realized by the cooperation of the processor 101 that executes the vehicle management program 105 and the storage device 102. The vehicle management program 105 is stored in the storage device 102. Alternatively, the vehicle management program 105 may be recorded on a computer-readable recording medium.

[0018] For example, the vehicle management system 100 has a function as a sound management system that manages sounds related to the electric vehicle 10. As a function of the sound management system, the vehicle management system 100 generates and manages the sound output from the speaker 70 mounted on the electric vehicle 10. In particular, as a function of the sound management system, the vehicle management system 100 generates an artificial sound that changes in response to the driving state of the electric vehicle 10. Then, the vehicle management system 100 outputs the generated artificial sound from the speaker 70 mounted on the electric vehicle 10. The driving state of the electric vehicle 10 is the operating state of the driving operation members (e.g., accelerator pedal, brake pedal, steering wheel) by the driver, the driving state of the electric vehicle 10, etc. Examples of the artificial sound that changes in response to the driving state include a "pseudo engine sound" that simulates the engine sound of an engine vehicle. An engine vehicle is a vehicle equipped with an engine (internal combustion engine) and having the engine as a driving source.

[0019] Note that the artificial sound generated and output from the speaker 70 is not limited to the pseudo engine sound. For example, the artificial sound may be a pseudo driving sound that simulates the driving sound of a moving body different from an automobile (e.g., train, airplane, etc.). As another example, the artificial sound may be music. In the following description, as an example, it is described that the artificial sound is a "pseudo engine sound". However, the technical features of the present disclosure described below are similarly applicable to other artificial sounds. When generalizing, the "pseudo engine sound" in the following description should be appropriately read as "artificial sound".

[0020] FIG. 2 is a block diagram showing a basic functional configuration of the vehicle management system 100 as a sound management system. The vehicle management system 100 includes, as functional blocks, a driving state acquisition unit 110, a sound source data management unit 120, an engine sound generation unit 130, and a sound output control unit 140. These functional blocks are realized, for example, by the cooperation of a processor 101 that executes the vehicle management program 105 and a storage device 102.

[0021] The driving state acquisition unit 110 acquires driving state information DRV, which indicates the driving state of the electric vehicle 10. Typically, the driving state information DRV includes information detected by sensors 11 mounted on the electric vehicle 10. For example, the driving state information DRV includes the amount of accelerator pedal operation (accelerator opening), the amount of brake pedal operation (brake opening), steering angle, steering speed, steering torque, wheel speed, vehicle speed, longitudinal acceleration, lateral acceleration, rotational speed of the electric motor 44, etc. The driving state information DRV may also include the position of the electric vehicle 10.

[0022] Furthermore, the driving state information DRV includes the virtual engine rotation speed Ne. Here, it is assumed that the electric vehicle 10 uses a virtual engine as the power source for driving. The virtual engine rotation speed Ne is the rotation speed of the virtual engine when it is assumed that the electric vehicle 10 is driven by the virtual engine. For example, the driving state acquisition unit 110 may calculate the virtual engine rotation speed Ne so that it increases as the wheel speed increases. Also, if the electric vehicle 10 has a manual mode (MT mode) as described later, the driving state acquisition unit 110 may calculate the virtual engine rotation speed Ne in manual mode based on the wheel speed, the overall reduction ratio, and the slip ratio of the virtual clutch. Details of the method for calculating the virtual engine rotation speed Ne in manual mode will be described later.

[0023] The sound source data management unit 120 stores and manages sound source data EVS used to generate simulated engine sounds. The sound source data management unit 120 is mainly implemented by one or more storage devices 102. Typically, the sound source data EVS includes multiple types of sound source data. These multiple types of sound source data include, for example, sound source data for sounds caused by engine combustion (for low, medium, and high RPMs), sound source data for sounds caused by the drive system such as gears (for low, medium, and high RPMs), noise sound source data, event sound (e.g., grinding noise, engine stall sound) sound source data, etc. Each sound source data is pre-generated through simulations based on engine models and vehicle models of engine-powered vehicles. Each sound source data is flexibly adjustable. That is, at least one of the sound pressure and frequency of the sound indicated by the sound source data can be flexibly adjusted.

[0024] The engine sound generation unit 130 (engine sound simulator) is a simulator that generates a simulated engine sound. The engine sound generation unit 130 acquires at least a portion of the driving state information DRV from the driving state acquisition unit 110. In particular, the engine sound generation unit 130 acquires information on the virtual engine rotation speed Ne and vehicle speed from the driving state acquisition unit 110. The engine sound generation unit 130 also reads the sound source data EVS from the sound source data management unit 120. Then, the engine sound generation unit 130 generates a simulated engine sound that changes in response to the driving state of the electric vehicle 10 (virtual engine rotation speed Ne and vehicle speed) by combining one or more sound source data included in the sound source data EVS. The engine sound data ES is data that represents the generated simulated engine sound.

[0025] The method for generating the simulated engine sound is not particularly limited in this embodiment. For example, a well-known method used in games, etc., may be employed. Alternatively, for example, a method may be used in which the frequency is increased or decreased in proportion to the virtual engine rotation speed Ne, and the sound pressure is increased or decreased in proportion to the virtual engine torque, according to a map of virtual engine rotation speed Ne-frequency and a map of virtual engine torque-sound pressure.

[0026] The sound output control unit 140 acquires engine sound data ES generated by the engine sound generation unit 130. Based on the engine sound data ES, the sound output control unit 140 outputs a simulated engine sound from the speaker 70.

[0027] 2. Simulated engine sound that responds to the driving conditions of other vehicles. 2.1 Overview As described above, the vehicle management system 100 outputs artificial sounds, particularly simulated engine sounds, from the speaker 70 in response to the driving state of the electric vehicle 10. This allows the driver to enjoy simulated engine sounds while driving the electric vehicle 10. In particular, by listening to the simulated engine sounds, the driver can enjoy a sense of realism as if they were driving a gasoline-powered vehicle.

[0028] By providing a function that allows drivers to enjoy such simulated engine sounds more, user satisfaction can be improved. One of the things that drivers find enjoyable is the change in the simulated engine sound related to the driving of the electric vehicle 10. Therefore, the inventors of this disclosure focused on other vehicles driving around the electric vehicle 10 as an element related to the driving of the electric vehicle 10. While the electric vehicle 10 is driving, the driving conditions of other vehicles driving around the electric vehicle 10 are constantly changing. By reflecting these changes in the driving conditions of other vehicles in the changes in the simulated engine sound output from the speaker 70, it is expected that drivers will be able to enjoy the simulated engine sound more.

[0029] From the above perspective, the vehicle management system 100 according to this embodiment is configured to provide two functions so that the driver can enjoy the simulated engine sound more. One is a function to change the sound source of the simulated engine sound in response to the driving conditions of other vehicles (hereinafter also simply referred to as "other vehicles") around the electric vehicle 10 (hereinafter referred to as the "sound source change function"). The other is a function to generate a harmonized sound that harmonizes with the simulated engine sound in response to the driving conditions of other vehicles and output it from the speaker 70 (hereinafter referred to as the "harmonized sound output function"). The outlines of each function will be described below.

[0030] Figure 3 is a conceptual diagram illustrating the overview of the sound source change function. First, the sound source change function recognizes the driving status of other vehicles. Figure 3 shows a case where four other vehicles 2a, 2b, 2c, and 2d are recognized around the electric vehicle 10.

[0031] Next, the sound source change function determines whether the recognized other vehicle includes the target vehicle (first target vehicle) related to the sound source change function. The first target vehicle is a vehicle that belongs to one of several types of vehicle models (vehicle model A, vehicle model B, vehicle model C, ...) managed by the vehicle management system 100. In Figure 3, other vehicles 2a, 2b, and 2c are first target vehicles, while other vehicle 2d is not. In particular, the vehicle management system 100 manages multiple sound source data EVS (EVS-1, EVS-2, EVS-3, ...) corresponding to each of the multiple types of vehicle models. The first target vehicle can also be described as a vehicle for which the corresponding sound source data EVS is managed. Sound source data EVS-i (i=1,2,3,...) typically indicates a sound source for generating a pseudo-engine sound that simulates the engine sound of the corresponding vehicle model.

[0032] When other recognized vehicles include the first target vehicles, one is selected from the first target vehicles. The selection may be configured to be made by driver 1. For example, the vehicle management system 100 displays a list of the first target vehicles on the HMI 12 and accepts selection input from driver 1 for each vehicle on the list.

[0033] Once a selection is made, the sound source for the simulated engine sound is changed to the sound source corresponding to the vehicle type of the selected first target vehicle (selected vehicle). More specifically, the sound source data EVS used by the engine sound generation unit 130 to generate the simulated engine sound is changed to the sound source data EVS corresponding to the vehicle type of the selected vehicle. As a result, the sound source change function outputs the simulated engine sound of the sound source corresponding to the vehicle type of the selected vehicle from the speaker 70. Figure 3 shows the case where another vehicle 2b is the selected vehicle. It also shows the case where the sound source data EVS used by the engine sound generation unit 130 to generate the simulated engine sound is changed from the original sound source data EVS-X to sound source data EVS-2 corresponding to vehicle type B.

[0034] In the sound source change function, if the recognized other vehicles do not include the first target vehicle, or if no other vehicles are recognized, the sound source will not be changed. Furthermore, the system may be configured not to change the sound source if the driver does not select the first target vehicle. Additionally, after the sound source has been changed, the system may be configured to revert to the original sound source data EVS-X upon request from driver 1.

[0035] Thus, with the sound source change function, when a first target vehicle is present around the electric vehicle 10, the sound source of the simulated engine sound can be changed to a sound source corresponding to the vehicle type of the first target vehicle. This allows driver 1 to enjoy various simulated engine sounds in response to the driving conditions of other vehicles. In particular, by enabling driver 1 to select the first target vehicle, driver 1 can change the simulated engine sound to a sound source corresponding to a vehicle type that interests them when they see one while driving the electric vehicle 10. In this way, the sound source change function allows driver 1 to enjoy the simulated engine sound output from speaker 70 even more.

[0036] Next, we will explain the overview of the harmonic sound output function. Figures 4A to 4C are conceptual diagrams illustrating the overview of the harmonic sound output function. First, the harmonic sound output function, like the sound source change function, recognizes the driving status of other vehicles. Figure 4A shows the case when no other vehicles are recognized. Figure 4B shows the case when one other vehicle 2v is recognized. Figure 4C shows the case when three other vehicles 2u, 2v, and 2w are recognized.

[0037] Next, the harmonic sound output function determines whether the recognized other vehicle includes a target vehicle (second target vehicle) related to the harmonic sound output function. The second target vehicle is a vehicle that is in a specific positional relationship with the electric vehicle 10. An example of a specific positional relationship is that it is located within a certain distance behind the electric vehicle 10. In other words, in this case, the second target vehicle is a following vehicle that is within a certain distance from the electric vehicle 10. The specific positional relationship can be appropriately determined depending on the situation in which this embodiment is applied. For example, the specific positional relationship can be that it is located within a certain distance in front of the electric vehicle 10. The following describes the case where the second target vehicle is a following vehicle of the electric vehicle 10.

[0038] In the harmonic sound output function, when the recognized other vehicles include a second target vehicle (following vehicle), a harmonic sound corresponding to each of the second target vehicles is generated. Each harmonic sound is generated, for example, based on the frequency of the simulated engine sound output from speaker 70. For example, each harmonic sound is generated to be an overtone of the simulated engine sound. Furthermore, the sound source of each harmonic sound may be changed according to the type of vehicle of the corresponding second target vehicle. Then, each generated harmonic sound is superimposed on the simulated engine sound and output from speaker 70.

[0039] In the example shown in Figure 4A, no other vehicle is recognized, so no harmonic sound is generated. Therefore, only a simulated engine sound is output from speaker 70. In the example shown in Figure 4B, other vehicle 2v becomes the second target vehicle, and a first harmonic sound corresponding to other vehicle 2v is generated. Both a simulated engine sound and the first harmonic sound are output from speaker 70. In the example shown in Figure 4C, other vehicles 2v and 2w become the second target vehicles, and first and second harmonic sounds corresponding to other vehicles 2v and 2w are generated, respectively. Both a simulated engine sound and the first and second harmonic sounds are output from speaker 70.

[0040] Thus, with the harmonic sound output function, when a second target vehicle is present around the electric vehicle 10, the speaker 70 outputs a harmonic sound corresponding to each second target vehicle, superimposed on the simulated engine sound. The superimposition of the harmonic sounds makes the simulated engine sound output from the speaker 70 feel more substantial to the driver 1. Furthermore, as the number of superimposed harmonic sounds increases, the substantiality of the simulated engine sound becomes even more pronounced. As a result, the driver 1 can enjoy the changes in the simulated engine sound in response to the driving conditions of other vehicles. In this way, the harmonic sound output function allows the driver 1 to enjoy the simulated engine sound output from the speaker 70 more.

[0041] As described above, the vehicle management system 100 according to this embodiment is configured to provide a sound source modification function and a harmonic sound output function. However, the vehicle management system 100 may be configured to provide only one of the sound source modification function or the harmonic sound output function. The configuration of the vehicle management system 100 related to each function will be described in detail below.

[0042] 2.1 Configuration related to the sound source change function Figure 5A is a block diagram showing an example of the functional configuration of a vehicle management system 100 related to the sound source change function. In the example shown in Figure 5A, the vehicle management system 100 includes, in addition to the functional blocks described in Figure 2, another vehicle recognition unit 150 and a sound source change determination unit 160. These functional blocks are realized, for example, through the cooperation of a processor 101 that executes a vehicle management program 105 and a storage device 102.

[0043] The sound source data management unit 120 stores multiple sound source data EVS (EVS-1, EVS-2, ..., EVS-N) corresponding to each of the multiple types of vehicle models, compared to the case described in Figure 2. The sound source data EVS-i (1≦i≦N) is pre-generated through simulations based on the engine model and vehicle model of the corresponding vehicle model. The engine sound generation unit 130 is configured to read one of the multiple sound source data EVS. In the initial state, the engine sound generation unit 130 may read a specific sound source data EVS (e.g., EVS-1), or it may read a randomly selected sound source data EVS.

[0044] The other vehicle recognition unit 150 recognizes other vehicles traveling around the electric vehicle 10 and acquires the driving status OVS of the recognized other vehicles. The other vehicle recognition unit 150 acquires the driving status OVS based, for example, on detection information detected by various sensors 11 and communication information received by the communication device 13. The driving status OVS includes information such as the number of other vehicles, the position or relative position of each other vehicle, the type of each other vehicle, and the driving status of each other vehicle (vehicle speed, acceleration, posture, etc.). The other vehicle recognition unit 150 transmits the acquired driving status OVS to the sound source change determination unit 160.

[0045] The sound source change determination unit 160 determines whether to change the sound source of the simulated engine sound as follows: The sound source change determination unit 160 determines from the driving situation OVS whether other vehicles include one or more first target vehicles. If other vehicles do not include the first target vehicles, the sound source change determination unit 160 determines not to change the sound source. On the other hand, if other vehicles include one or more first target vehicles, the sound source change determination unit 160 acquires one of the one or more first target vehicles as the selected target vehicle. The sound source change determination unit 160 may be configured to accept selection input from the driver 1 via the HMI 12 and to make the selected first target vehicle the selected target vehicle. When the sound source change determination unit 160 acquires the selected target vehicle, it determines to change the sound source and outputs a change request CR to the engine sound generation unit 130. The change request CR includes information on the sound source data EVS corresponding to the vehicle type of the selected target vehicle.

[0046] When the engine sound generation unit 130 receives a change request CR from the sound source change determination unit 160, it reads the target sound source data EVS-k from the sound source data management unit 120 according to the change request CR. Then, the engine sound generation unit 130 generates a pseudo-engine sound using the read sound source data EVS-k.

[0047] By providing the vehicle management system 100 with this functional configuration, the sound source change function can be realized. Figure 5B is a flowchart showing an example of the processing flow of the process (first process) that the vehicle management system executes with respect to the sound source change function based on the functional configuration described above. The processing flow shown in Figure 5B may be executed repeatedly at a predetermined processing cycle.

[0048] First, the vehicle management system 100 recognizes other vehicles traveling around the electric vehicle 10 (step S110) and obtains the OVS (Optical Vehicle Status) of the other vehicles (step S120).

[0049] Next, the vehicle management system 100 determines from the acquired driving status OVS whether the other vehicles include one or more first target vehicles that belong to one of the multiple types of vehicles managed (step S130). If the other vehicles do not include the first target vehicles (step S130; No), the process ends without changing the sound source.

[0050] If other vehicles include one or more first target vehicles (step S130; Yes), the vehicle management system 100 acquires one of the one or more first target vehicles as a selected target vehicle (step S140). Then, the vehicle management system 100 changes the sound source of the simulated engine sound to the sound source corresponding to the vehicle type of the selected target vehicle (step S150). After step S150, this process ends.

[0051] 2.2 Configuration related to the harmonic sound output function Figure 6A is a block diagram showing an example of the functional configuration of a vehicle management system 100 related to the harmonic sound output function. In the example shown in Figure 6A, the vehicle management system 100 includes, in addition to the functional blocks described in Figure 2, a vehicle recognition unit 150 and a harmonic sound generation unit 170. However, the vehicle recognition unit 150 is the same as the one described in Figure 5A. These functional blocks are realized, for example, through the cooperation of a processor 101 that executes a vehicle management program 105 and a storage device 102.

[0052] The harmonic sound generation unit 170 acquires the driving status (OVS) of other vehicles from the other vehicle recognition unit 150. The harmonic sound generation unit 170 also reads sound source data (EVS) from the sound source data management unit 120, similar to the engine sound generation unit 130. Furthermore, the harmonic sound generation unit 170 acquires the generation specification GS of the generated pseudo-engine sound from the engine sound generation unit 130. The generation specification GS includes information such as the sound pressure and frequency of the pseudo-engine sound, and the sound source data used.

[0053] The harmonic sound generation unit 170 determines from the acquired driving conditions OVS whether the other vehicles include one or more second target vehicles (following vehicles). If the other vehicles do not include second target vehicles, the harmonic sound generation unit 170 does not generate harmonic sounds. On the other hand, if the other vehicles include second target vehicles, the harmonic sound generation unit 170 generates one or more harmonic sounds corresponding to one or more second target vehicles from the sound source data EVS and generation specifications GS. The harmonic sound data HS is data indicating the one or more harmonic sounds that were generated.

[0054] When the sound output control unit 140 acquires harmonic sound data HS from the harmonic sound generation unit 170, it superimposes the harmonic sound onto the simulated engine sound based on the harmonic sound data HS and outputs it from the speaker 70.

[0055] By providing the functional configuration of the vehicle management system 100 in this way, the harmonic sound generation function can be realized. Figure 6B is a flowchart showing an example of the processing flow of the process (second process) that the vehicle management system 100 performs with respect to the harmonic sound generation function based on the functional configuration described above. The processing flow shown in Figure 6B may be executed repeatedly at a predetermined processing cycle.

[0056] First, the vehicle management system 100 recognizes other vehicles traveling around the electric vehicle 10 (step S210) and obtains the OVS (Optical Vehicle Status) of the other vehicles (step S220).

[0057] Next, the vehicle management system 100 determines from the acquired driving status OVS whether the other vehicle includes one or more second target vehicles (following vehicles) (step S230). If the other vehicle does not include second target vehicles (step S230; No), the process ends without outputting a harmonic sound.

[0058] If the other vehicles include one or more second target vehicles (step S230; Yes), the vehicle management system 100 generates a harmonic sound corresponding to each second target vehicle (step S240). Then, the vehicle management system 100 superimposes the generated harmonic sound onto the simulated engine sound and outputs it from the speaker 70 (step S250). After step S250, this process ends.

[0059] 3. Application to electric vehicles equipped with manual mode (MT mode) The electric motors used as the power source for driving in conventional electric vehicles (EVs) have significantly different torque characteristics compared to the internal combustion engines used as the power source for conventional vehicles (CVs). Due to these differences in torque characteristics, CVs require a transmission, whereas electric vehicles generally do not. Of course, conventional electric vehicles do not have a manual transmission (MT) that allows the driver to manually switch gear ratios. Therefore, there is a significant difference in driving feel between driving a manual transmission vehicle (hereinafter referred to as an MT vehicle) and driving an electric vehicle.

[0060] On the other hand, the torque of an electric motor can be controlled relatively easily by controlling the applied voltage and field. Therefore, with an electric motor, it is possible to obtain the desired torque characteristics within the motor's operating range by implementing appropriate control. Taking advantage of this characteristic, the torque of an electric vehicle can be controlled to simulate the torque characteristics unique to a manual transmission (MT) vehicle. Furthermore, to allow the driver to experience a driving sensation similar to that of an MT vehicle, a pseudo-shifter that mimics the gear shifting components used in an MT vehicle can be installed in the electric vehicle. In this way, it becomes possible to simulate an MT vehicle in an electric vehicle.

[0061] In other words, the electric vehicle controls the output of the electric motor to simulate the driving characteristics (torque characteristics) unique to a manual transmission (MT) vehicle. The driver operates a simulated shifter to perform a simulated manual gear change. In response to the driver's simulated manual gear change, the electric vehicle changes its driving characteristics (torque characteristics) to simulate an MT vehicle. As a result, the driver of the electric vehicle can get the feeling that they are driving an MT vehicle. The electric motor control mode used to simulate the driving characteristics and manual gear change operation of an MT vehicle will be referred to as "manual mode" or "MT mode" below.

[0062] The electric vehicle 10 described herein may also be equipped with such a manual mode (MT mode). In MT mode, the electric vehicle 10 generates a simulated engine sound in response to the driver's driving operations and outputs the simulated engine sound from the speaker 70. Not only the driving operations of an MT vehicle but also the engine sound of an MT vehicle are reproduced, thus increasing the satisfaction of drivers seeking realism.

[0063] The following describes an example configuration of an electric vehicle 10 equipped with a manual mode (MT mode).

[0064] Figure 7 is a block diagram showing an example configuration of the power control system of the electric vehicle 10 according to this embodiment. The battery 46 stores electrical energy to drive the electric motor 44. In other words, the electric vehicle 10 is a battery electric vehicle (BEV) that runs on the electrical energy stored in the battery 46. The inverter 42 converts the DC power input from the battery 46 during acceleration into driving power for the electric motor 44. The inverter 42 also converts the regenerative power input from the electric motor 44 during deceleration into DC power and charges the battery 46.

[0065] The electric vehicle 10 is equipped with an accelerator pedal 22 for the driver to input an acceleration request to the electric vehicle 10. The accelerator pedal 22 is equipped with an accelerator position sensor 32 for detecting the accelerator opening degree.

[0066] The electric vehicle 10 is equipped with a sequential shifter 24. The sequential shifter 24 is a simulated shifter that mimics the shifter found in a genuine manual transmission vehicle. The sequential shifter 24 may be a paddle-type simulated shifter or a lever-type simulated shifter.

[0067] In the case of a paddle-type pseudo-shifter, the sequential shifter 24 is equipped with an upshift switch and a downshift switch that determine the operating position. The upshift switch emits an upshift signal when pulled towards the user, and the downshift switch emits a downshift signal when pulled towards the user.

[0068] On the other hand, in the case of a lever-type pseudo-shifter, the sequential shifter 24 is configured to output an upshift signal when the shift lever is moved forward and a downshift signal when the shift lever is moved backward.

[0069] Wheel speed sensors 36 are provided on the wheels of the electric vehicle 10. The wheel speed sensors 36 are used as vehicle speed sensors to detect the vehicle speed of the electric vehicle 10. In addition, a rotational speed sensor 38 is provided on the electric motor 44 to detect its rotational speed.

[0070] The electric vehicle 10 is equipped with a control device 50. The control device 50 is typically an electronic control unit (ECU) installed in the electric vehicle 10. The control device 50 may be a combination of multiple ECUs.

[0071] The control device 50 controls the electric motor 44 by PWM control of the inverter 42. The control device 50 processes various input signals and calculates a motor torque command value for PWM control of the inverter 42.

[0072] The control device 50 includes an automatic mode (EV mode) and a manual mode (MT mode) as control modes. The automatic mode is programmed to continuously change the output of the electric motor 44 in response to the operation of the accelerator pedal 22. On the other hand, the manual mode is a control mode for driving the electric vehicle 10 like a manual transmission vehicle. In manual mode, the output characteristics of the electric motor 44 in response to the operation of the accelerator pedal 22 are programmed to change in response to upshift and downshift operations on the sequential shifter 24.

[0073] The control device 50 includes an automatic mode torque calculation unit 54 and a manual mode torque calculation unit 56. Each unit 54 and 56 may be an independent ECU, or it may be an ECU function obtained by executing a program stored in memory on a processor.

[0074] The automatic mode torque calculation unit 54 has a function to calculate the motor torque when the electric motor 44 is controlled in automatic mode. The automatic mode torque calculation unit 54 stores a motor torque command map. The motor torque command map is a map that determines the motor torque from the accelerator opening and the rotational speed of the electric motor 44. Signals from the accelerator position sensor 32 and the rotational speed sensor 38 are input to each parameter of the motor torque command map. The motor torque corresponding to these signals is output from the motor torque command map. Therefore, in automatic mode, even if the driver operates the sequential shifter 24, that operation is not reflected in the motor torque.

[0075] The manual mode torque calculation unit 56 includes an MT vehicle model. The MT vehicle model is a model for calculating the drive wheel torque that should be obtained by operating the accelerator pedal 22 and the sequential shifter 24, assuming that the electric vehicle 10 is an MT vehicle.

[0076] The MT vehicle model includes an engine model, a clutch model, and a transmission model. The engine model calculates virtual engine speed and virtual engine output torque. Virtual engine speed is calculated from wheel speed, overall reduction ratio, and virtual clutch slip ratio. Virtual engine output torque is calculated from virtual engine speed and accelerator opening. A map that defines the relationship between accelerator opening, virtual engine speed, and virtual engine output torque is used to calculate virtual engine output torque.

[0077] The clutch model calculates the torque transmission gain. The torque transmission gain is used to calculate the degree of torque transmission by the virtual clutch according to the virtual clutch opening. A map that defines the relationship between the virtual clutch opening and the torque transmission gain is used to calculate the torque transmission gain.

[0078] The clutch model calculates the clutch output torque using the torque transfer gain. The clutch output torque is the torque output from the virtual clutch. The clutch model also calculates the slip ratio. The slip ratio is used to calculate the virtual engine speed in the engine model. Similar to the torque transfer gain, a map can be used to calculate the slip ratio, where the slip ratio is assigned to the virtual clutch opening.

[0079] The transmission model calculates the gear ratio. The gear ratio is determined by the virtual gear stage in the virtual transmission. A map that defines the relationship between the gear ratio and the virtual gear stage is used to calculate the gear ratio. The transmission model uses the gear ratio obtained from the map and the clutch output torque to calculate the transmission output torque. The transmission output torque changes discontinuously in accordance with the gear ratio change. This discontinuous change in transmission output torque creates a shift shock, creating the impression of a vehicle with a stepped transmission.

[0080] In the MT vehicle model, the drive wheel torque is calculated from the transmission output torque calculated by the transmission model using a predetermined reduction ratio. For example, the drive wheel torque is given by the product of the transmission output torque and the reduction ratio.

[0081] The control device 50 converts the drive wheel torque calculated in the MT vehicle model into the required motor torque. The required motor torque is the motor torque necessary to achieve the drive wheel torque calculated in the MT vehicle model. The reduction ratio from the output shaft of the electric motor 44 to the drive wheels is used to convert the drive wheel torque into the required motor torque. The control device 50 then controls the electric motor 44 via the control of the inverter 42 according to the required motor torque.

[0082] In this way, the control device 50 performs torque control of the electric motor 44 in manual mode. As described above, in manual mode, the motor torque output by the electric motor 44 changes in response to the operation state of the accelerator pedal 22 and the sequential shifter 24 (pseudo-shifter).

[0083] The above example configuration describes the case where the simulated shifter is composed of a sequential shifter 24. The configuration of the simulated shifter may also be other forms that are expected in actual manual transmission vehicles. For example, the simulated shifter may consist of a simulated shift lever and a simulated clutch pedal. The simulated shift lever has positions corresponding to each gear, for example, 1st, 2nd, 3rd, 4th, 5th, reverse, and neutral. The simulated clutch pedal is operated when the simulated shift lever is operated. In such a configuration, the control device 50 can control the electric motor 44 in both automatic and manual modes in the same manner as described above. However, in such a configuration, the control device 50 determines the virtual gear by the shift position of the simulated shift lever in manual mode. [Explanation of symbols]

[0084] 10 electric vehicles, 44 electric motors, 70 speakers, 100 vehicle management systems, 101 Processor, 102 Storage device, 105 Vehicle management program

Claims

1. An electric vehicle having an electric motor as its driving source, The system comprises one or more processors configured to generate artificial sounds that change in response to the driving state of the electric vehicle and to output the artificial sounds from a speaker mounted on the electric vehicle. The one or more processors further include: The electric vehicle recognizes the driving conditions of other vehicles traveling around it. In response to the driving conditions of the other vehicle, at least one of the following processes is performed: a first process that changes the sound source of the artificial sound, and a second process that generates a harmonized sound that harmonizes with the artificial sound, superimposes the harmonized sound on the artificial sound, and outputs it from the speaker. It is configured in such a way An electric vehicle characterized by the following features.

2. An electric vehicle according to claim 1, The system further comprises one or more storage devices that store multiple sound sources corresponding to multiple types of vehicle models, The one or more processors are configured to execute the first process when the other vehicles include one or more first target vehicles that fall under any of the multiple types of vehicle models. In the first processing, the one or more processors Obtain one selected target vehicle from the one or more first target vehicles described above, The sound source of the artificial sound is changed to the sound source corresponding to the vehicle type of the selected vehicle from among the plurality of sound sources. It is configured in such a way An electric vehicle characterized by the following features.

3. An electric vehicle according to claim 1, The one or more processors are configured to perform the second process when the other vehicle includes one or more second target vehicles that are in a specific positional relationship with the electric vehicle. The aforementioned harmonic sound includes one or more harmonic sounds corresponding to each of the one or more second target vehicles. An electric vehicle characterized by the following features.

4. An electric vehicle according to claim 3, The one or more of the aforementioned second target vehicles are vehicles following the electric vehicle. An electric vehicle characterized by the following features.

5. An electric vehicle according to any one of claims 1 to 4, The aforementioned artificial sound is a simulated engine sound that mimics the sound of a gasoline engine. An electric vehicle characterized by the following features.

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