Electric vehicles and vehicle management systems

Abstract

To provide an electric vehicle in which pseudo engine sounds to be output respectively to a vehicle interior and a vehicle exterior are appropriately controlled in consideration of each of a function for a driver and a function for surrounding people.SOLUTION: An electric vehicle includes speakers including a vehicle interior speaker that outputs sound to a vehicle interior and a vehicle exterior speaker that outputs sound to a vehicle exterior. The electric vehicle also includes one or more processors configured to generate a pseudo engine sound and output the pseudo engine sound from the speaker. When vehicle speed of the electric vehicle is higher than first speed, the one or more processors outputs the pseudo engine sound from the vehicle interior speaker without outputting the pseudo engine sound from the vehicle exterior speaker. When the vehicle speed of the electric vehicle is equal to or lower than the first speed, the one or more processors also output the pseudo engine sound from both the vehicle interior speaker and the vehicle exterior speaker.SELECTED DRAWING: Figure 3

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 vehicle control device that generates a pseudo engine sound (virtual sound) that occurs when driving in a virtual vehicle equipped with a virtual engine as a drive source in a real vehicle equipped with an electric motor (rotating machine) as a drive source. In addition, there is the following Patent Document 2 as a document showing the technical level of the technical field related to the present disclosure.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] An electric vehicle has a small driving sound of an electric motor, and the running sound during low-speed driving is particularly quiet. Therefore, there is a concern that people around may not notice the presence of the vehicle during low-speed driving. Therefore, in an electric vehicle, it is required to notify people around of the approach of the vehicle during low-speed driving.

[0005] Simulated engine sounds are attracting attention because they can give drivers a sense of realism, making them feel as if they are driving a vehicle powered by an internal combustion engine (a gasoline-powered vehicle). On the other hand, the engine sounds produced by actual gasoline-powered vehicles are also transmitted outside the vehicle, serving to notify people nearby of the vehicle's approach. However, conventionally, controlling the output of simulated engine sounds while considering this function has not been sufficiently considered. Simulated engine sounds emitted outside the vehicle may, depending on the situation, simply become noise.

[0006] One objective of this disclosure is to provide an electric vehicle that can appropriately control the simulated engine sound output inside and outside the vehicle, taking into consideration both the function for the driver and the function for people in the surrounding area. [Means for solving the problem]

[0007] The first aspect relates to an electric vehicle that uses an electric motor as a power source for driving. The electric vehicle is equipped with speakers, including in-cabin speakers that output sound inside the vehicle and external speakers that output sound outside the vehicle. The electric vehicle is also equipped with one or more processors configured to generate a simulated engine sound and output the simulated engine sound from the speakers. When the vehicle speed of the electric vehicle is greater than a first speed, the one or more processors output a simulated engine sound from the in-cabin speakers without outputting the simulated engine sound from the external speakers. When the vehicle speed of the electric vehicle is less than or equal to the first speed, the one or more processors output a simulated engine sound from both the in-cabin speakers and the external speakers.

[0008] The second aspect relates to a vehicle management system applicable to electric vehicles that use an electric motor as the power source for driving. The vehicle management system comprises one or more processors configured to generate a simulated engine sound and output the simulated engine sound from speakers mounted on the electric vehicle. The speakers mounted on the electric vehicle include in-cabin speakers that output sound inside the vehicle and external speakers that output sound outside the vehicle. Alternatively, when the vehicle speed of the electric vehicle is greater than a first speed, the processors output a simulated engine sound from the in-cabin speakers without outputting the simulated engine sound from the external speakers. Also, when the vehicle speed of the electric vehicle is less than or equal to the first speed, the processors output a simulated engine sound from both the in-cabin speakers and the external speakers. [Effects of the Invention]

[0009] According to this disclosure, when the electric vehicle's speed is greater than the first speed, a simulated engine sound is output from the in-vehicle speakers, but not from the exterior speakers. When the electric vehicle's speed falls below the first speed, a simulated engine sound is output from both the in-vehicle and exterior speakers. This gives the driver a sense of realism as if they were driving a gasoline-powered vehicle. Furthermore, the simulated engine sound can notify people in the vicinity that the vehicle is approaching when the electric vehicle is traveling at low speeds below the first speed. In addition, when the electric vehicle's speed is greater than the first speed, no simulated engine sound is output from the exterior speakers. Therefore, it is possible to prevent the simulated engine sound from becoming mere noise.

[0010] In particular, the simulated engine sound output from the external speakers is also output from the internal speakers. Moreover, the output of the simulated engine sound from the internal speakers continues before and after the start of the output from the external speakers. As a result, even when the output of the simulated engine sound from the external speakers begins, the driver can continue driving naturally without feeling any discomfort. [Brief explanation of the drawing]

[0011] [Figure 1] This is a conceptual diagram showing an electric vehicle and vehicle management system according to an embodiment. [Figure 2] Block diagram showing an example of the functional configuration of a vehicle management system. [Figure 3] This flowchart shows the processes executed by the output unit of the vehicle management system. [Figure 4] This is a block diagram showing an example of the functional configuration of the output unit in a modified form. [Figure 5] This is a block diagram showing a first example configuration of a power control system for an electric vehicle. [Figure 6] This block diagram shows a second example configuration of a power control system for an electric vehicle. [Modes for carrying out the invention]

[0012] Embodiments of this disclosure will be described with reference to the attached drawings.

[0013] 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 is equipped with an electric motor 44. 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.

[0014] The electric vehicle 10 is also 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 wheel speed sensor, an acceleration sensor, a rotational speed sensor, a position sensor, a sound level meter, and the like. 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 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 sound level meter measures the noise level around the electric vehicle 10.

[0015] Furthermore, the electric vehicle 10 is equipped with speakers. The speakers installed in the electric vehicle include an in-vehicle speaker 70a that outputs sound inside the electric vehicle 10 and an external speaker 70b that outputs sound outside the electric vehicle 10.

[0016] The vehicle management system 100 is applied to such an electric vehicle 10 and manages the electric vehicle 10. The vehicle management system 100 has the function of a sound management system that manages sounds related to the electric vehicle 10. In particular, the vehicle management system 100 generates and manages the sounds output from speakers mounted on the electric vehicle 10. Furthermore, the vehicle management system 100 outputs the generated sounds through speakers mounted on the electric vehicle 10.

[0017] 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 a management server outside the electric vehicle 10. In that case, the vehicle management system 100 may remotely manage sounds related to the electric vehicle 10. As yet another example, the vehicle management system 100 may be distributed between the electric vehicle 10 and the management server.

[0018] 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. Examples of the processor 101 include 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, and / or a combination thereof. The processor 101 can also be referred to as circuitry or processing circuitry. The circuitry is hardware programmed to implement the described functions or hardware that executes the functions. The storage device 102 stores (stores) various information. Examples of the storage device 102 include a volatile memory, a non-volatile memory, a HDD (Hard Disk Drive), a SSD (Solid State Drive), and the like. Through the cooperation of the processor 101 and the storage device 102, the functions of the vehicle management system 100 are realized.

[0019] 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 10,5 may be recorded on a computer-readable recording medium.

[0020] Output of pseudo engine sound 2.1 Overview The vehicle management system 100 according to this embodiment, in its function as a sound management system, generates a "simulated engine sound" that mimics the engine sound generated in a vehicle (engine vehicle) that has an internal combustion engine as its power source. The vehicle management system 100 then outputs the simulated engine sound through a speaker installed in the electric vehicle 10.

[0021] Incidentally, the electric vehicle 10 is equipped with an in-car speaker 70a and an external speaker 70b. The simulated engine sound output from the in-car speaker 70a is transmitted inside the vehicle and heard by at least the driver. Therefore, by outputting a simulated engine sound from the in-car speaker 70a, it is possible to give the driver a sense of realism as if they were driving a gasoline-powered vehicle.

[0022] On the other hand, the simulated engine sound output from the external speaker 70b is transmitted outside the vehicle and is mainly heard by people around the electric vehicle 10. Engine sound is a sound unique to vehicles. Therefore, as is the case with actual engine-powered vehicles, it is expected that people around who hear the simulated engine sound will recognize that a vehicle is approaching from the direction from which the sound is coming. Thus, by outputting a simulated engine sound from the external speaker 70b, it is possible to notify people around that a vehicle is approaching. However, the simulated engine sound output from the external speaker 70b may, depending on the circumstances, simply become noise.

[0023] The vehicle management system 100 is configured to output a simulated engine sound from either the in-vehicle speaker 70a or the external speaker 70b, taking into consideration each of the above functions. The vehicle management system 100 as a sound management system will be described in detail below.

[0024] 2.2 Functional Configuration Figure 2 is a block diagram showing the 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 an output unit 140. These functional blocks may be realized through the cooperation of a processor 101 that executes the vehicle management program 105 and a storage device 102.

[0025] The driving status acquisition unit 110 acquires driving information DRV related to the electric vehicle 10. The driving information DRV includes information about the driver's driving operations, information about the driving state of the electric vehicle 10, information about the driving environment in which the electric vehicle 10 is located, etc. Typically, the driving information DRV includes sensor detection information detected by sensors 11 mounted on the electric vehicle 10. For example, the sensor detection information includes the amount of accelerator pedal operation (accelerator opening), the amount of brake pedal operation (brake opening), wheel speed, vehicle speed, longitudinal acceleration, rotational speed of the electric motor 44, the position of the electric vehicle 10 on a map, etc. The sensor detection information may also include the noise level around the electric vehicle 10.

[0026] Furthermore, the driving 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.

[0027] The sound source data management unit 120 stores and manages basic sound source data 200 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 basic sound source data 200 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 rotational speeds), sound source data for sounds caused by the drive system such as gears (for low, medium, and high rotational speeds), 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.

[0028] 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 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 basic sound source data 200 from the sound source data management unit 120. Then, the engine sound generation unit 130 generates a simulated engine sound corresponding 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 basic sound source data 200. The engine sound data ES is data that indicates the generated simulated engine sound.

[0029] Furthermore, the generation of simulated engine sounds is a well-known technique and is not particularly limited in this embodiment. For example, simulated engine sounds may be generated using a well-known engine sound simulator used in games, etc. Alternatively, one could have a map of virtual engine rotation speed Ne-frequency and a map of virtual engine torque-sound pressure, and increase or decrease the frequency of the simulated engine sound in proportion to the virtual engine rotation speed Ne, and increase or decrease the sound pressure in proportion to the virtual engine torque.

[0030] The output unit 140 receives engine sound data ES generated by the engine sound generation unit 130. The output unit 140 further acquires vehicle speed information of the electric vehicle 10 as driving information DRV from the driving state acquisition unit 110. The output unit 140 performs the process of outputting a simulated engine sound based on the engine sound data ES from either the in-vehicle speaker 70a or the external speaker 70b. In this process, the output unit 140 operates to use different speakers to output the simulated engine sound depending on the vehicle speed.

[0031] Figure 3 is a flowchart showing the process executed by the output unit 140. The process shown in the flowchart of Figure 3 may be repeatedly executed at a predetermined processing cycle.

[0032] In step S100, the output unit 140 acquires various information. In particular, the output unit 140 acquires engine sound data ES from the engine sound generation unit 130. The output unit 140 also acquires vehicle speed information of the electric vehicle 10 from the driving state acquisition unit 110.

[0033] Next, in step S110, the output unit 140 determines whether the acquired vehicle speed of the electric vehicle 10 is greater than the first speed or less than or equal to the first speed. The first speed is a threshold value that indicates when the electric vehicle 10 is traveling at a low speed. The specific value of the first speed may be suitably determined depending on the environment in which this embodiment is applied.

[0034] When the vehicle speed of the electric vehicle 10 is greater than the first speed (step S110; Yes), the output unit 140 outputs a simulated engine sound based on the engine sound data ES from the in-vehicle speaker 70a (step S120). In particular, at this time, the output unit 140 does not output a simulated engine sound from the external speaker 70b. After step S120, the output unit 140 terminates the current process.

[0035] When the vehicle speed of the electric vehicle 10 falls below the first speed (step S110; No), the output unit 140 outputs a simulated engine sound from both the in-vehicle speaker 70a and the external speaker 70b (step S130). After step S130, the output unit 140 terminates the current process.

[0036] As explained above, the output unit 140 performs processing. According to the processing performed by the output unit 140, when the vehicle speed of the electric vehicle 10 is greater than the first speed, the simulated engine sound is output towards the inside of the vehicle but not towards the outside. When the vehicle speed of the electric vehicle 10 is less than or equal to the first speed and the vehicle is traveling at a low speed, the simulated engine sound is output both towards the inside and outside of the vehicle.

[0037] 2.3 Effects As described above, according to the vehicle management system 100 of this embodiment, when the vehicle speed of the electric vehicle 10 is greater than the first speed, a simulated engine sound is output from the in-vehicle speaker 70a, and no simulated engine sound is output from the external speaker 70b. When the vehicle speed of the electric vehicle 10 falls below the first speed, a simulated engine sound is output from both the in-vehicle speaker 70a and the external speaker 70b. In other words, the output of the simulated engine sound from the in-vehicle speaker 70a is performed while the electric vehicle 10 is in motion. On the other hand, the output of the simulated engine sound from the external speaker 70b is performed only when the electric vehicle 10 is traveling at a low speed.

[0038] This allows the driver to experience the feeling of driving a gasoline-powered vehicle while the electric vehicle 10 is in motion. Furthermore, at low speeds when the electric vehicle 10's engine noise is quiet, the simulated engine sound can notify people in the vicinity that the vehicle is approaching. Additionally, as the electric vehicle 10's speed increases, the output of the simulated engine sound directed outside the vehicle is stopped, preventing the simulated engine sound from becoming mere noise.

[0039] In particular, the simulated engine sound output from the external speaker 70b is also output from the internal speaker 70a. Moreover, the output of the simulated engine sound from the internal speaker 70a continues before and after the start of the output of the simulated engine sound from the external speaker 70b. Therefore, even when the output of the simulated engine sound from the external speaker 70b begins, the driver can continue driving naturally without any sense of discomfort. Furthermore, the driver can drive while being aware of the sounds that people around them would likely hear.

[0040] The vehicle management system 100 may also be configured to notify the driver that it is outputting a simulated engine sound from the external speaker 70b. For example, the vehicle management system 100 notifies the driver by displaying a message or generating a sound via the HMI installed in the electric vehicle 10. By providing such a notification, the driver can recognize that people in the surrounding area are being notified of the vehicle's approach.

[0041] 2.4 Variations The simulated engine sound output from the external speaker 70b will sound different to people in the vicinity depending on the noise level around the electric vehicle 10. For example, even if the same simulated engine sound is output, when the noise level is high, the simulated engine sound will sound quieter to people in the vicinity, and when the noise level is low, the simulated engine sound will sound louder to people in the vicinity. Therefore, depending on the noise level around the electric vehicle 10, the notification of the vehicle's approach by the simulated engine sound may not function effectively. For example, if the noise level is high, people in the vicinity may not be able to perceive the simulated engine sound. Also, if the noise level is low, people in the vicinity may perceive the simulated engine sound as too loud.

[0042] Therefore, the output unit 140 further acquires information on the noise level around the electric vehicle 10 as driving information DRV from the driving state acquisition unit 110. The output unit 140 can then be configured to change the characteristics of the simulated engine sound output from the external speaker 70b according to the noise level.

[0043] Figure 4 is a block diagram showing the functional configuration of the output unit 140 in a modified example. In the example shown in Figure 4, the output unit 140 includes a correction unit 141 and an output control unit 142.

[0044] The correction unit 141 receives engine sound data ES generated by the engine sound generation unit 130 and the ambient noise level around the electric vehicle 10 as input. The correction unit 141 corrects the engine sound data ES according to the noise level. For example, the correction unit 141 corrects the engine sound data ES to change the sound pressure of the simulated engine sound using a sound pressure map M10. The sound pressure map M10 is designed so that the sound pressure of the simulated engine sound increases as the noise level increases. In particular, the sound pressure map M10 may be designed to provide a sound pressure that allows people in the vicinity to perceive the simulated engine sound appropriately in relation to the noise level. Alternatively, the correction unit 141 may correct the engine sound data ES to change the frequency and timbre of the simulated engine sound according to the noise level.

[0045] The output control unit 142 receives the vehicle speed of the electric vehicle 10, engine sound data ES generated by the engine sound generation unit 130, and engine sound data ESr corrected by the correction unit 141 as input. The processing in the output control unit 142 is equivalent to the processing described in Figure 3. However, the output control unit 142 outputs a simulated engine sound based on the engine sound data ES from the in-vehicle speaker 70a, and a simulated engine sound based on the corrected engine sound data ESr from the external speaker 70b.

[0046] As explained above, according to the modified version, the characteristics of the simulated engine sound output from the external speaker 70b change according to the noise level around the electric vehicle 10. This makes it possible to adjust the simulated engine sound output from the external speaker 70b so that it can be appropriately perceived by people in the vicinity, especially in relation to the noise level. Consequently, the notification of the vehicle's approach to people in the vicinity using the simulated engine sound can be made to function effectively.

[0047] 2.5 Others The vehicle management system 100 can also be configured to generate and output other artificial sounds from a speaker instead of a simulated engine sound. Examples of artificial sounds that can be generated include simulated driving sounds that mimic the driving sounds of vehicles other than automobiles (e.g., trains, airplanes, etc.). Another example is that the artificial sound may be music. In this case, the functional configuration of the vehicle management system 100 can be similarly realized by appropriately replacing "simulated engine sound" with "artificial sound" in the above description.

[0048] In this case, the artificial sounds emitted from the in-car speaker 70a are not intended to give the driver a sense of realism as if they were driving a gasoline-powered vehicle. Instead, the artificial sounds emitted from the in-car speaker 70a may be intended to provide entertainment for the driver.

[0049] Furthermore, the vehicle management system 100 may be configured to allow the driver to select a notification sound different from the simulated engine sound to be output from the external speaker 70b. For example, the vehicle management system 100 may be configured to receive a selection of a sound to be output from the external speaker 70b from the driver via the HMI installed in the electric vehicle 10. The sound source data management unit 120 may be further configured to manage the notification sound data. The content of the notification sound may be designed as appropriate. For example, a notification sound could be an artificial sound that repeats a specific pitch, such as "beep, beep,...". If the driver selects a notification sound other than the simulated engine sound, the output unit 140 will output the notification sound from the external speaker 70b based on the data read from the sound source data management unit 120 when the vehicle speed of the electric vehicle 10 is below the first speed.

[0050] 3. Application to electric vehicles equipped with manual mode (MT mode) The electric motors used as the power source in conventional electric vehicles (EVs) have significantly different torque characteristics compared to the internal combustion engines used as the power source in 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 conventional vehicle with an MT (hereinafter referred to as an MT vehicle) and driving an electric vehicle.

[0051] 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, a simulated shifter can be installed in an electric vehicle to allow the driver to experience a driving sensation similar to that of an MT vehicle. In this way, it becomes possible to simulate an MT vehicle in an electric vehicle.

[0052] In other words, the electric vehicle controls the output of the electric motor to simulate the 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 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. This control mode of the electric motor for simulating the torque characteristics and manual gear change operation of an MT vehicle will be referred to below as "manual mode" or "MT mode". In contrast to the manual mode (MT mode), the normal control mode for driving the electric vehicle 10 as a typical electric vehicle will be referred to below as "automatic mode" or "EV mode".

[0053] The electric vehicle 10 described herein may be equipped with such a manual mode (MT mode). The manual mode (MT mode) and automatic mode (EV mode) may be switchable by the driver. In manual mode (MT mode), the electric vehicle 10 generates a simulated engine sound in response to the driver's driving operations. 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.

[0054] In particular, the vehicle management system 100 may be configured to stop the output of the simulated engine sound from the in-vehicle speaker 70a when the automatic mode (EV mode) is selected. Furthermore, the vehicle management system 100 may be configured to output a notification sound different from the simulated engine sound from the external speaker 70b when the automatic mode (EV mode) is selected. That is, when the vehicle speed of the electric vehicle 10 falls below the first speed, a notification sound is output from the external speaker 70b. The content of the notification sound may be set as appropriate. With this configuration, in automatic mode (EV mode), the driver can operate the electric vehicle 10 without hearing the engine sound from the in-vehicle speaker 70a. In addition, people in the vicinity can be notified of the vehicle's approach with a normal notification sound at low speeds. In this way, the automatic mode (EV mode) achieves the operation of a typical electric vehicle, even in terms of the sound output from the speakers. Consequently, the driver can enjoy driving the electric vehicle 10 in automatic mode (EV mode) without any discomfort.

[0055] The following describes an example configuration of an electric vehicle 10 equipped with a manual mode (MT mode).

[0056] 3.1 First Configuration Example (Sequential Shifter) Figure 5 is a block diagram showing a first configuration example 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.

[0057] 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 provided with an accelerator position sensor 32 for detecting the accelerator opening degree.

[0058] The electric vehicle 10 is equipped with a sequential shifter 24. The sequential shifter 24 may be a paddle-type shifter or a lever-type pseudo-shifter.

[0059] The paddle shifters are dummies and not genuine paddle shifters. The paddle shifters have an upshift switch and a downshift switch that determine the operating position. When the upshift switch is pulled towards the driver, it emits an upshift signal 34u, and when the downshift switch is pulled towards the driver, it emits a downshift signal 34d.

[0060] On the other hand, the lever-type pseudo-shifter, like the paddle-type shifter, is a dummy and not a real shifter. The lever-type pseudo-shifter is configured to output an upshift signal 34u when the shift lever is moved forward, and a downshift signal 34d when the shift lever is moved backward.

[0061] Wheel speed sensors 36 are provided on the wheels 26 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.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] The vehicle model consists of an engine model, a clutch model, and a transmission model. The engine model calculates the virtual engine speed and virtual engine output torque. The virtual engine 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 speed and the throttle opening. A map that defines the relationship between the throttle opening, virtual engine speed, and virtual engine output torque is used to calculate the virtual engine output torque.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] 3.2 Second Configuration Example Figure 6 is a block diagram showing a second configuration example of the power control system of the electric vehicle 10 according to this embodiment. Here, only the configurations that differ from the first configuration example described above will be explained. Specifically, in the second configuration example, the electric vehicle 10 is equipped with a pseudo-shift lever (pseudo-shift device) 27 and a pseudo-clutch pedal 28 instead of the sequential shifter 24 provided in the first configuration example. The pseudo-shift lever 27 and pseudo-clutch pedal 28 are merely dummies and are different from the actual shift lever and clutch pedal.

[0073] The simulated shift lever 27 has a structure that mimics the shift lever found in a manual transmission (MT) vehicle. The placement and feel of the simulated shift lever 27 are equivalent to those of an actual MT vehicle. The simulated shift lever 27 has positions corresponding to each gear, such as 1st, 2nd, 3rd, 4th, 5th, 6th, reverse, and neutral. The simulated shift lever 27 is equipped with a shift position sensor 27a that detects the gear by determining which position the simulated shift lever 27 is in.

[0074] The simulated clutch pedal 28 has a structure that simulates the clutch pedal found in a manual transmission vehicle. The simulated clutch pedal 28 is operated when the simulated shift lever 27 is operated. The simulated clutch pedal 28 is equipped with a clutch position sensor 28a for detecting the amount of depression of the simulated clutch pedal 28.

[0075] The control device 50 receives signals from the accelerator position sensor 32, the shift position sensor 27a, the clutch position sensor 28a, the wheel speed sensor 36, and the rotational speed sensor 38. The control device 50 processes these signals and calculates a motor torque command value for PWM control of the inverter 42.

[0076] The control device 50, similar to the first configuration example described above, includes an automatic mode and a manual 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. The manual mode is programmed to change the output and output characteristics of the electric motor 44 in response to the operation of the accelerator pedal 22 in response to the operation of the simulated clutch pedal 28 and the simulated shift lever (simulated shift device) 27. In other words, the manual mode is a control mode that can change the output of the electric motor 44 in response to driving operations of vehicle components other than the accelerator pedal 22 or brake pedal.

[0077] The vehicle model provided by the manual mode torque calculation unit 56 is the same as described above. However, the virtual clutch opening is replaced by the amount of depression of the pseudo clutch pedal 28 detected by the clutch position sensor 28a. In addition, the virtual gear position is determined by the position of the pseudo shift lever 27 detected by the shift position sensor 27a. [Explanation of Symbols]

[0078] 10 Electric vehicles, 70a In-car speakers, 70b Exterior speakers, 100 Vehicle management system, 101 Processor, 102 Storage device

Claims

1. An electric vehicle that uses an electric motor as a power source for driving, A speaker system including in-car speakers that output sound inside the vehicle and external speakers that output sound outside the vehicle, One or more processors configured to generate a simulated engine sound and output the simulated engine sound from the speaker, Equipped with, The one or more processors described above are: When the vehicle speed of the electric vehicle is greater than the first speed, the simulated engine sound is not output from the external speaker, but the simulated engine sound is output from the internal speaker. When the vehicle speed of the electric vehicle is less than or equal to the first speed, The simulated engine sound is output from both the in-vehicle speaker and the out-of-vehicle speaker. The noise level around the aforementioned electric vehicle is obtained, The characteristics of the simulated engine sound output from the external speaker are changed according to the noise level. It is configured in such a way Electric vehicle.

2. An electric vehicle according to claim 1, It also features an accelerator pedal and a sequential shifter, In manual mode, the output characteristics of the electric motor in response to the operation of the accelerator pedal are configured to change according to the shift operation of the sequential shifter. Electric vehicle.

3. An electric vehicle according to claim 1, It further includes an accelerator pedal, a simulated clutch pedal, and a simulated shift device. The aforementioned simulated clutch pedal is operated when the simulated shift device is operated. In manual mode, the output of the electric motor in response to the operation of the accelerator pedal is configured to change according to the operation of the simulated clutch pedal and the operation of the simulated shift device. Electric vehicle.

4. An electric vehicle according to claim 2 or 3, It is configured to be switchable between the manual mode and an automatic mode in which the output of the electric motor is changed in response to the operation of the accelerator pedal. The one or more processors, when the electric vehicle is in automatic mode, The output of the simulated engine sound from the in-vehicle speaker is stopped. When the vehicle speed of the electric vehicle is less than or equal to the first speed, a notification sound different from the simulated engine sound is output from the external speaker. It is configured in such a way Electric vehicle.

5. A vehicle management system applicable to electric vehicles that use an electric motor as a power source for driving, The system comprises one or more processors configured to generate a simulated engine sound and output the simulated engine sound from a speaker mounted on the electric vehicle, The aforementioned speaker includes an in-car speaker that outputs sound inside the vehicle and an external speaker that outputs sound outside the vehicle. The one or more processors described above are: When the vehicle speed of the electric vehicle is greater than the first speed, the simulated engine sound is not output from the external speaker, but the simulated engine sound is output from the internal speaker. When the vehicle speed of the electric vehicle is less than or equal to the first speed, The simulated engine sound is output from both the in-vehicle speaker and the out-of-vehicle speaker. The noise level around the aforementioned electric vehicle is obtained, The characteristics of the simulated engine sound output from the external speaker are changed according to the noise level. It is configured in such a way Vehicle management system.

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