Electric vehicle

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

[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 reproduce the engine sound generated during a shift change 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 is possible for the driver to enjoy the driving of 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 satisfaction. It is considered that one of the pleasures that the driver feels is 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 state 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 the artificial sound by paying attention to the change in the running state of other vehicles running around the electric vehicle.

Means for Solving the Problems

[0006] One aspect of the present disclosure relates to an electric vehicle having an electric motor as a drive source. The electric vehicle includes one or more processors configured to generate an artificial sound that changes in response to an operating state of the electric vehicle and output the artificial sound from a speaker mounted on the electric vehicle. The one or more processors are further configured to recognize a driving situation of other vehicles traveling around the electric vehicle and execute at least one of the following first process and second process in response to the recognized driving situation of the other vehicles. The first process is a process of changing a sound source of the artificial sound. The second process is a process of generating a harmonic sound that harmonizes with the artificial sound, superimposing the harmonic sound on the artificial sound, and outputting the result from the speaker.

Advantages of the Invention

[0007] According to the present disclosure, by executing the first process and the second process in response to the driving situation of other vehicles, it is possible to reflect a change in the driving situation of other vehicles in a change in the artificial sound output from the speaker. As a result, it is possible to provide a function that allows a driver to enjoy the artificial sound more. As a result, the satisfaction of the user of the electric vehicle can be improved.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Mode for Carrying Out the Invention

[0009] Embodiments of the present disclosure will be described with reference to the accompanying drawings.

[0010] 1 Electric Vehicle and Vehicle Management System FIG. 1 is a conceptual diagram showing an electric vehicle 10 and a vehicle management system 100 according to the present 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 driving device for traveling.

[0011] In addition, the electric vehicle 10 is equipped with various sensors 11. The various sensors 11 detect the operating state of the electric vehicle 10. Examples of the various 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, a recognition sensor, etc. The accelerator position sensor detects the operation amount of the accelerator pedal. The brake position sensor detects the operation amount 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 acceleration 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 the position sensor is a GNSS (Global Navigation Satellite System) sensor. The recognition sensor is a sensor for recognizing (detecting) the situation around the electric vehicle 10. Examples of the recognition sensor include a camera, a lidar (Light Detection And Ranging), a radar, etc.

[0012] In addition, 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 inside the passenger compartment of the electric vehicle 10. As another example, the speaker 70 may be an out-vehicle speaker that outputs sound outside the electric vehicle 10. The electric vehicle 10 may be equipped with both an in-vehicle speaker and an out-vehicle speaker.

[0013] In addition, 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 by means of display and sound, and also receives various inputs from the user. The HMI 12 is composed of a display (e.g., a multi-information display, a meter display), a switch, a speakerphone, a touch panel, etc. The speaker 70 may be configured as part of the HMI 12.

[0014] In addition, the electric vehicle 10 is provided with a communication device 13 that communicates with an external device to transmit and receive information. Examples of the communication device 13 include a device that connects to the Internet to transmit and receive information with various servers, a device that communicates with infrastructure facilities to transmit and receive infrastructure information, a device that transmits and receives information with surrounding vehicles to transmit and receive other vehicle information, and the like.

[0015] The vehicle management system 100 is applied to such an electric vehicle 10 to manage the electric vehicle 10. The entire vehicle management system 100 may be mounted on the electric vehicle 10. As another example, at least a part of the vehicle management system 100 may be included in a 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. The functions of the vehicle management system 100 are realized by the cooperation of the processor 101 and the storage device 102.

[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 running state of the electric vehicle 10, etc. An example of the artificial sound that changes in response to the driving state is the "pseudo engine sound" that simulates the engine sound of a gasoline-powered vehicle. A gasoline-powered vehicle is a vehicle equipped with an engine (internal combustion engine) and having the engine as a power 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 the "pseudo engine sound". However, the technical features of the present disclosure described below are equally 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 the 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 a vehicle management program 105 and a storage device 102.

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

[0022] Further, the driving state information DRV includes the virtual engine rotational speed Ne. Here, it is assumed that the electric vehicle 10 uses a virtual engine as a power device for running. The virtual engine rotational speed Ne is the rotational 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 rotational speed Ne so as to increase as the wheel speed increases. Further, when the electric vehicle 10 is provided with a manual mode (MT mode) described later, the driving state acquisition unit 110 may calculate the virtual engine rotational speed Ne in the manual mode based on the wheel speed, the overall reduction ratio, and the slip ratio of the virtual clutch. Details of the calculation method of the virtual engine rotational speed Ne in this manual mode will be described later.

[0023] The sound source data management unit 120 stores and manages the sound source data EVS used to generate the pseudo engine sound. 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. The multiple types of sound source data include, for example, sound source data of the sound caused by engine combustion (for low engine speeds, medium engine speeds, and high engine speeds), sound source data of the sound caused by the drive system such as gears (for low engine speeds, medium engine speeds, and high engine speeds), sound source data of noise, sound source data of event sounds (e.g., clicking sound, stalling sound), and the like. Each sound source data is pre-generated through simulations based on the engine model and vehicle model of the engine vehicle. Each sound source data can be flexibly adjusted. 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 pseudo engine sound. The engine sound generation unit 130 acquires at least a part 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. Also, the engine sound generation unit 130 reads the sound source data EVS from the sound source data management unit 120. Then, the engine sound generation unit 130 generates a pseudo engine sound that changes in response to the driving state (virtual engine rotation speed Ne and vehicle speed) of the electric vehicle 10 by combining one or more sound source data included in the sound source data EVS. The engine sound data ES is data indicating the generated pseudo engine sound.

[0025] Note that the method for generating the pseudo engine sound is not particularly limited in this embodiment. For example, a well-known method adopted in games or the like may be adopted. Also, for example, a method of increasing or decreasing the frequency in proportion to the virtual engine rotation speed Ne and increasing or decreasing the sound pressure in proportion to the virtual engine torque according to the virtual engine rotation speed Ne - frequency map and virtual engine torque - sound pressure map may be used.

[0026] The sound output control unit 140 acquires the 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 pseudo engine sound from the speaker 70.

[0027] 2 Pseudo engine sound in response to the driving conditions of other vehicles 2.1 Overview As described above, according to the vehicle management system 100, an artificial sound, particularly a pseudo engine sound, in response to the driving state of the electric vehicle 10 is output from the speaker 70. Thereby, the driver can enjoy the pseudo engine sound during the driving of the electric vehicle 10. In particular, the driver can enjoy a sense of presence as if driving an engine vehicle by listening to the pseudo engine sound.

[0028] By providing a function that allows the driver to enjoy such a pseudo engine sound more, the user satisfaction can be improved. One of the things that the driver can feel pleasure in is considered to be the change in the pseudo engine sound related to the driving of the electric vehicle 10. Therefore, the inventor according to the present disclosure focused on other vehicles traveling around the electric vehicle 10 as an element related to the driving of the electric vehicle 10. While the electric vehicle 10 is traveling, the driving conditions of other vehicles traveling around the electric vehicle 10 are constantly changing. By reflecting the change in the driving conditions of these other vehicles in the change in the pseudo engine sound output from the speaker 70, it can be expected that the driver can enjoy the pseudo engine sound more.

[0029] From the above viewpoints, the vehicle management system 100 according to the present embodiment is configured to provide two functions so that the driver can enjoy the pseudo engine sound more. One is a function of changing the sound source of the pseudo 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 of generating a harmony sound that harmonizes with the pseudo engine sound in response to the driving conditions of other vehicles and outputting it from the speaker 70 (hereinafter referred to as the "harmony sound output function"). Hereinafter, the outline of each function will be described.

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

[0031] Next, in the sound source change function, it is determined 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 corresponding to any of a plurality of vehicle types (vehicle type A, vehicle type B, vehicle type C,...) managed by the vehicle management system 100. In Figure 3, the other vehicles 2a, 2b, and 2c are the first target vehicles, while the other vehicle 2d is not the first target vehicle. In particular, the vehicle management system 100 manages a plurality of sound source data EVS (EVS-1, EVS-2, EVS-3,...) corresponding to each of the plurality of vehicle types. The first target vehicle can also be described as a vehicle for which the corresponding sound source data EVS is managed. The 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 type.

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

[0033] When a selection is made, the sound source of the pseudo engine sound is changed to the sound source corresponding to the vehicle type of the selected first target vehicle (selected target vehicle). More specifically, the sound source data EVS used by the engine sound generation unit 130 to generate the pseudo engine sound is changed to the sound source data EVS corresponding to the vehicle type of the selected target vehicle. As a result, in the sound source change function, the pseudo engine sound of the sound source corresponding to the vehicle type of the selected target vehicle is output from the speaker 70. FIG. 3 shows a case where the other vehicle 2b is the selected target vehicle. And it shows the case where the sound source data EVS used by the engine sound generation unit 130 to generate the pseudo engine sound is changed from the original sound source data EVS-X to the sound source data EVS-2 corresponding to vehicle type B.

[0034] In the sound source change function, when the recognized other vehicle does not include the first target vehicle, or when no other vehicle is recognized, the sound source is not changed. Also, when the driver does not select the first target vehicle, it may be configured not to change the sound source. Further, after the sound source is changed, it may be configured to be able to return to the original sound source data EVS-X according to a request from the driver 1.

[0035] According to the sound source change function in this way, when the first target vehicle exists around the electric vehicle 10, the sound source of the pseudo engine sound can be changed to the sound source corresponding to the vehicle type of the first target vehicle. Thereby, the driver 1 can enjoy the pseudo engine sounds of various sound sources in response to the driving conditions of other vehicles. In particular, by enabling the driver 1 to select the first target vehicle, when the driver 1 sees a vehicle type that attracts interest during the driving of the electric vehicle 10, the driver 1 can change it to the pseudo engine sound of the sound source corresponding to that vehicle type and enjoy it. In this way, with the sound source change function, the driver 1 can enjoy the pseudo engine sound output from the speaker 70 more.

[0036] Next, the outline of the harmonic sound output function will be described. FIGS. 4A to 4C are conceptual diagrams for explaining the outline of the harmonic sound output function. First, in the harmonic sound output function, similar to the sound source change function, the driving situation of other vehicles is recognized. FIG. 4A shows a case where no other vehicle is recognized. FIG. 4B shows a case where one other vehicle 2v is recognized. FIG. 4C shows a case where three other vehicles 2u, 2v, and 2w are recognized.

[0037] Next, in the harmonic sound output function, it is determined whether the recognized other vehicle includes the target vehicle (second target vehicle) related to the harmonic sound output function. The second target vehicle is a vehicle in a specific positional relationship with the electric vehicle 10. As an example of the specific positional relationship, it may be located within a certain distance range behind the electric vehicle 10. That is, in this case, the second target vehicle is a following vehicle within a certain distance range from the electric vehicle 10. The specific positional relationship can be appropriately determined according to the situation to which the present embodiment is applied. For example, the specific positional relationship may be that it is located within a certain distance range in front of the electric vehicle 10. Hereinafter, the case where the second target vehicle is a following vehicle of the electric vehicle 10 will be described.

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

[0039] In the example shown in FIG. 4A, since no other vehicle is recognized, no harmonic sound is generated. Therefore, only the pseudo engine sound is output from the speaker 70. In the example shown in FIG. 4B, the other vehicle 2v becomes the second target vehicle, and the first harmonic sound corresponding to the other vehicle 2v is generated. The pseudo engine sound and the first harmonic sound are output from the speaker 70. In the example shown in FIG. 4C, the other vehicles 2v and 2w become the second target vehicles, and the first harmonic sound and the second harmonic sound corresponding to each of the other vehicles 2v and 2w are generated. The pseudo engine sound, the first harmonic sound, and the second harmonic sound are output from the speaker 70.

[0040] According to the harmonic sound output function in this way, when a second target vehicle exists around the electric vehicle 10, the harmonic sound corresponding to each second target vehicle is output from the speaker 70 superimposed on the pseudo engine sound. By superimposing the harmonic sound, the driver 1 can feel the pseudo engine sound output from the speaker 70 as being more substantial. Furthermore, as the number of superimposed harmonic sounds increases, the substantiality of the pseudo engine sound becomes more prominent. As a result, the driver 1 can enjoy the change in the pseudo engine sound in response to the driving situation of other vehicles. In this way, with the harmonic sound output function, the driver 1 can enjoy the pseudo engine sound output from the speaker 70 more.

[0041] As described above, the vehicle management system 100 according to the present embodiment is configured to provide a sound source change function and a harmonic sound output function. Note that the vehicle management system 100 may be configured to provide only one of the sound source change function and the harmonic sound output function. Hereinafter, the configuration of the vehicle management system 100 related to each function will be described in detail.

[0042] 2.1 Configuration Related to Sound Source Change Function FIG. 5A is a block diagram showing an example of the functional configuration of a vehicle management system 100 related to a sound source change function. In the example shown in FIG. 5A, the vehicle management system 100 includes an other vehicle recognition unit 150 and a sound source change determination unit 160 in addition to the functional blocks described in FIG. 2. These functional blocks are realized, for example, by 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 a plurality of sound source data EVS (EVS-1, EVS-2, ···, EVS-N) corresponding to each of a plurality of vehicle types as compared with the case described in FIG. 2. The sound source data EVS-i (1 ≤ i ≤ N) is generated in advance through simulations based on the engine model and vehicle model of the corresponding vehicle type. The engine sound generation unit 130 is configured to read one of the plurality of sound source data EVS. In the initial state, the engine sound generation unit 130 may read a specific sound source data EVS (for example, EVS-1), or 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 obtains the driving situation OVS of the recognized other vehicles. The other vehicle recognition unit 150 obtains the driving situation OVS based on, for example, detection information detected by various sensors 11 and communication information received by the communication device 13. The driving situation OVS includes information such as the number of other vehicles, the position or relative position of each other vehicle, the vehicle type of each other vehicle, the driving state (vehicle speed, acceleration, attitude, etc.) of each other vehicle, and the like. The other vehicle recognition unit 150 transmits the obtained driving situation 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 pseudo engine sound as follows. The sound source change determination unit 160 determines whether the other vehicles include one or more first target vehicles from the driving situation OVS. When the 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, when the other vehicles include one or more first target vehicles, the sound source change determination unit 160 acquires one selected target vehicle among the one or more first target vehicles. The sound source change determination unit 160 may be configured to receive a selection input from the driver 1 via the HMI 12 and set the selected first target vehicle as the selected target vehicle. When the sound source change determination unit 160 acquires the selected target vehicle, it determines to perform a change of 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 acquires the 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 functional configuration of the vehicle management system 100 in this way, the sound source change function can be realized. FIG. 5B is a flowchart showing an example of the processing flow (first processing) executed by the vehicle management system regarding the sound source change function based on the above-described functional configuration. The processing flow shown in FIG. 5B may be repeatedly executed at a predetermined processing cycle.

[0048] First, the vehicle management system 100 recognizes other vehicles traveling around the electric vehicle 10 (step S110) and acquires the driving situation OVS of the other vehicles (step S120).

[0049] Next, the vehicle management system 100 determines whether the acquired driving situation OVS includes one or more first target vehicles corresponding to any of a plurality of types of vehicle models managed by other vehicles (step S130). If the other vehicles do not include the first target vehicles (step S130; No), the current process ends without changing the sound source.

[0050] If the other vehicles include one or more first target vehicles (step S130; Yes), the vehicle management system 100 acquires one selection target vehicle among the one or more first target vehicles (step S140). Then, the vehicle management system 100 changes the sound source of the pseudo engine sound to the sound source corresponding to the vehicle model of the selection target vehicle (step S150). After step S150, the current process ends.

[0051] 2.2 Configuration related to the harmonic sound output function FIG. 6A is a block diagram showing an example of the functional configuration of the vehicle management system 100 related to the harmonic sound output function. In the example shown in FIG. 6A, the vehicle management system 100 includes an other vehicle recognition unit 150 and a harmonic sound generation unit 170 in addition to the functional blocks described in FIG. 2. However, the other vehicle recognition unit 150 is the same as that described in FIG. 5A. 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.

[0052] The harmonic sound generation unit 170 acquires the driving situation OVS of other vehicles from the other vehicle recognition unit 150. Also, the harmonic sound generation unit 170 reads the sound source data EVS from the sound source data management unit 120 in the same manner as 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, frequency, and used sound source data of the pseudo engine sound.

[0053] The harmony sound generation unit 170 determines whether the acquired driving situation OVS includes one or more second target vehicles (following vehicles). When the other vehicles do not include the second target vehicles, the harmony sound generation unit 170 does not generate a harmony sound. On the other hand, when the other vehicles include the second target vehicles, the harmony sound generation unit 170 generates one or more harmony sounds corresponding to each of the one or more second target vehicles from the sound source data EVS and the generation specification GS. The harmony sound data HS is data indicating the generated one or more harmony sounds.

[0054] When the sound output control unit 140 acquires the harmony sound data HS from the harmony sound generation unit 170, based on the harmony sound data HS, the harmony sound is superimposed on the pseudo engine sound and output from the speaker 70.

[0055] By providing the functional configuration of the vehicle management system 100 in this way, the harmony sound generation function can be realized. FIG. 6B is a flowchart showing an example of a processing flow (second processing) executed by the vehicle management system 100 regarding the harmony sound generation function based on the above-described functional configuration. The processing flow shown in FIG. 6B may be repeatedly executed at a predetermined processing cycle.

[0056] First, the vehicle management system 100 recognizes other vehicles traveling around the electric vehicle 10 (step S210) and acquires the driving situation OVS of the other vehicles (step S220).

[0057] Next, the vehicle management system 100 determines whether the acquired driving situation OVS includes one or more second target vehicles (following vehicles) (step S230). When the other vehicles do not include the second target vehicles (step S230; No), the harmony sound is not output and the current processing ends.

[0058] When the other vehicle includes one or a plurality of 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 on the pseudo engine sound and outputs it from the speaker 70 (step S250). After step S250, the current process ends.

[0059] 3 Application to an electric vehicle equipped with a manual mode (MT mode) An electric motor used as a driving power device in a general electric vehicle has significantly different torque characteristics from an internal combustion engine that has been used as a driving power device in a conventional vehicle (CV). Due to the difference in the torque characteristics of the power device, a CV requires a transmission, while a general electric vehicle generally does not have a transmission. Of course, a general electric vehicle does not have a manual transmission (MT) that switches the gear ratio by the driver's manual operation. For this reason, there is a significant difference in the driving feeling between driving a manual transmission vehicle (hereinafter referred to as an MT vehicle) and driving an electric vehicle.

[0060] On the other hand, an electric motor can relatively easily control torque by controlling the applied voltage and field excitation. Therefore, in an electric motor, by implementing appropriate control, it is possible to obtain desired torque characteristics within the operating range of the electric motor. Taking advantage of this feature, the torque of an electric vehicle can be controlled to simulate the torque characteristics peculiar to an MT vehicle. Also, a pseudo shifter that mimics the shifting member used in the shifting operation of an MT vehicle can be provided in the electric vehicle so that the driver can obtain a driving feeling like that of an MT vehicle. By these means, it becomes possible to simulate an MT vehicle in an electric vehicle.

[0061] That is, the electric vehicle controls the output of the electric motor so as to simulate the driving characteristics (torque characteristics) peculiar to an MT vehicle. The driver operates the pseudo shifter to perform a pseudo manual shifting operation. In response to the pseudo manual shifting operation by the driver, the electric vehicle changes the driving characteristics (torque characteristics) by simulating an MT vehicle. As a result, the driver of the electric vehicle can obtain a feeling as if driving an MT vehicle. Hereinafter, the control mode of the electric motor for simulating the driving characteristics and the manual shifting operation of the MT vehicle is referred to as the "manual mode" or the "MT mode".

[0062] The electric vehicle 10 according to the present disclosure may be provided with such a manual mode (MT mode). In the MT mode, the electric vehicle 10 generates a pseudo engine sound in response to the driving operation of the driver and outputs the pseudo engine sound from the speaker 70. Since not only the driving operation of the MT vehicle but also the engine sound of the MT vehicle are reproduced, the satisfaction of the driver who pursues reality is enhanced.

[0063] Hereinafter, a configuration example of the electric vehicle 10 provided with the manual mode (MT mode) will be described.

[0064] FIG. 7 is a block diagram showing a configuration example of the power control system of the electric vehicle 10 according to the present embodiment. The battery 46 stores electric energy for driving the electric motor 44. That is, the electric vehicle 10 is a battery electric vehicle (BEV) that runs on the electric energy stored in the battery 46. The inverter 42 converts the DC power input from the battery 46 during acceleration into the driving power of the electric motor 44. Further, the inverter 42 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 includes an accelerator pedal 22 for the driver to input an acceleration request to the electric vehicle 10. The accelerator pedal 22 is provided 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 pseudo shifter that imitates the shifter provided in a conventional MT vehicle. The sequential shifter 24 may be a paddle-type pseudo shifter or a lever-type pseudo shifter.

[0067] In the case of a paddle-type pseudo shifter, the sequential shifter 24 includes an upshift switch and a downshift switch for determining the operation position. The upshift switch generates an upshift signal when pulled forward, and the downshift switch generates a downshift signal when pulled forward.

[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 by tilting the shift lever forward and a downshift signal by tilting the shift lever backward.

[0069] A wheel speed sensor 36 is provided on the wheels of the electric vehicle 10. The wheel speed sensor 36 is used as a vehicle speed sensor for detecting the vehicle speed of the electric vehicle 10. In addition, a rotational speed sensor 38 for detecting the rotational speed is provided on the electric motor 44.

[0070] The electric vehicle 10 is equipped with a control device 50. The control device 50 is typically an electronic control unit (ECU) mounted on 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 according 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 an MT vehicle. The manual mode is programmed to change the output characteristics of the electric motor 44 with respect to the operation of the accelerator pedal 22 according to the upshift operation and downshift operation with respect to 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 of the units 54 and 56 may be an independent ECU, or may be a function of an ECU obtained by executing a program recorded in a memory by a processor.

[0074] The automatic mode torque calculation unit 54 has a function of calculating the motor torque when controlling the electric motor 44 in the automatic mode. A motor torque command map is stored in the automatic mode torque calculation unit 54. 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 the automatic mode, even if the driver operates the sequential shifter 24, the 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 when 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 a virtual engine rotational speed and a virtual engine output torque. The virtual engine rotational speed is calculated from the wheel speed, the overall reduction ratio, and the slip ratio of the virtual clutch. The virtual engine output torque is calculated from the virtual engine rotational speed and the accelerator opening. A map defining the relationship between the accelerator opening, the virtual engine rotational speed, and the virtual engine output torque is used in the calculation of the virtual engine output torque.

[0077] The clutch model calculates a torque transmission gain. The torque transmission gain is a gain for calculating the degree of torque transmission of the virtual clutch according to the virtual clutch opening. A map defining the relationship between the virtual clutch opening and the torque transmission gain is used in the calculation of the torque transmission gain.

[0078] The clutch model calculates the clutch output torque using the torque transmission gain. The clutch output torque is the torque output from the virtual clutch. Also, the clutch model calculates the slip ratio. The slip ratio is used in the calculation of the virtual engine rotational speed in the engine model. A map in which the slip ratio is given for the virtual clutch opening can be used in the calculation of the slip ratio, similar to the torque transmission gain.

[0079] The transmission model calculates the gear ratio (shift ratio). The gear ratio is the gear ratio determined by the virtual gear stage in the virtual transmission. A map defining the relationship between the gear ratio and the virtual gear stage is used in the calculation of the gear ratio. The transmission model calculates the transmission output torque using the gear ratio obtained from the map and the clutch output torque. The transmission output torque changes discontinuously according to the switching of the gear ratio. This discontinuous change in the transmission output torque generates a shift shock, creating the feel of a vehicle equipped 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 a required motor torque. The required motor torque is the motor torque necessary to realize the drive wheel torque calculated in the MT vehicle model. For the conversion of the drive wheel torque to the required motor torque, the reduction ratio from the output shaft of the electric motor 44 to the drive wheels is used. Then, the control device 50 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 executes torque control of the electric motor 44 in the manual mode. As described above, in the manual mode, the motor torque output by the electric motor 44 changes in response to the operation states of the accelerator pedal 22 and the sequential shifter 24 (simulated shifter).

[0083] In the above configuration example, the case where the simulated shifter is configured by the sequential shifter 24 has been described. Other forms assumed in an actual MT vehicle may be adopted for the configuration of the simulated shifter. For example, the simulated shifter may be configured by a simulated shift lever and a simulated clutch pedal. The simulated shift lever is provided with positions corresponding to each gear stage of, for example, first speed, second speed, third speed, fourth speed, fifth speed, reverse, and neutral. The simulated clutch pedal is operated when the simulated shift lever is operated. Even in such a configuration, the control device 50 can control the electric motor 44 in the same manner as described above in each of the automatic mode and the manual mode. However, in the case of such a configuration, the control device 50 determines the virtual gear stage by the shift position of the simulated shift lever in the manual mode.

Explanation of Reference Numerals

[0084] 10 Electric vehicle, 44 Electric motor, 70 Speaker, 100 Vehicle management system, 101 Processor, 102 Memory device, 105 Vehicle management program

Claims

1. An electric vehicle having an electric motor as a drive source, comprising one or more processors configured to generate an artificial sound that changes in response to an operating state of the electric vehicle and output the artificial sound from a speaker mounted on the electric vehicle, wherein the one or more processors further recognize a driving situation of other vehicles traveling around the electric vehicle, and execute at least one of a first process of changing a sound source of the artificial sound in response to the driving situation of the other vehicles and a second process of generating a harmonic sound that harmonizes with the artificial sound, superimposing the harmonic sound on the artificial sound, and outputting the result from the speaker. The electric vehicle is configured as described above. An electric vehicle characterized by the above.

2. The electric vehicle according to claim 1, further comprising one or more storage devices that store a plurality of sound sources corresponding to each of a plurality of vehicle types, wherein the one or more processors are configured to execute the first process when the other vehicle includes one or more first target vehicles corresponding to any of the plurality of vehicle types, and in the first process, the one or more processors acquire a selected target vehicle from among the one or more first target vehicles, and change the sound source of the artificial sound to a sound source corresponding to the vehicle type of the selected target vehicle among the plurality of sound sources. The electric vehicle is configured as described above. An electric vehicle characterized by the above.

3. The electric vehicle according to claim 1, wherein the one or more processors are configured to execute the second process when the other vehicle includes one or more second target vehicles in a specific positional relationship with the electric vehicle, and the 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 above.

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

5. The electric vehicle according to any one of claims 1 to 4, wherein the artificial sound is a pseudo engine sound that simulates the engine sound of an engine vehicle. An electric vehicle characterized by the above.

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