Vehicle management system and electric vehicle

Abstract

To further enhance reality of a pseudo engine sound relating to a technology for generating the pseudo engine sound in an electric vehicle having an electric motor as a drive source.SOLUTION: An electric vehicle includes one or more processors configured to generate a pseudo engine sound and output the pseudo engine sound from a speaker mounted on the electric vehicle. The one or more processors obtain a load weight of the electric vehicle. Then, the one or more processors change the pseudo engine sound in accordance with the load weight.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] Conventionally, in an electric vehicle, a technique of generating a pseudo engine sound that occurs when driving in a virtual engine vehicle having an internal combustion engine (engine) as a drive source has been considered. For example, Patent Document 1 discloses estimating the load applied to a virtual engine when the virtual engine is controlled based on a driving operation, and estimating the pseudo engine sound (virtual sound) generated in the vehicle interior when the virtual engine is controlled so as to have the estimated load, and a vehicle control device including a controller that controls an acoustic device so as to generate the estimated pseudo engine sound.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By generating a pseudo engine sound in an electric vehicle, it is possible to give the driver a sense of presence as if driving an engine vehicle. Furthermore, by enhancing the reality of the pseudo engine sound, it contributes to improving the satisfaction of the driver who wants to hear the pseudo engine sound.

[0005] The characteristics of the pseudo engine sound generated in an actual engine vehicle vary depending on the weight of the entire vehicle that the engine attempts to drive. The weight of the entire vehicle changes according to the number of passengers, the contents of the luggage loaded, etc., for each situation when driving is performed. Conventionally, the generation of a pseudo engine sound that reflects such a change in the weight of the entire vehicle has not been considered. One object of the present disclosure is to focus on the change in the weight of the entire vehicle and enhance the reality of the pseudo engine sound.

Means for Solving the Problem

[0006] The first aspect relates to an electric vehicle having an electric motor as a drive source. The electric vehicle includes one or more processors configured to generate a pseudo engine sound and output the pseudo engine sound from a speaker mounted on the electric vehicle. The one or more processors are configured to acquire the loaded weight of the electric vehicle and change the pseudo engine sound according to the loaded weight.

Effect of the Invention

[0007] According to the present disclosure, the pseudo engine sound output from the speaker changes according to the loaded weight of the electric vehicle. Thereby, a pseudo engine sound with higher reality can be output.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments 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 power device for traveling.

[0011] In addition, the electric vehicle 10 is equipped with various sensors 11. The various sensors 11 detect the driving 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 surrounding environment recognition sensor, and the like. 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 surrounding environment recognition sensor is a sensor for recognizing (detecting) the surrounding environment of the electric vehicle 10. Examples of the surrounding environment recognition sensor include a camera, a lidar (Light Detection And Ranging), a radar, and the like. The driver recognition sensor is a sensor for recognizing (detecting) the driver of the electric vehicle 10.

[0012] In the present embodiment, the various sensors 11 particularly include a weight sensor for detecting the load weight of the electric vehicle 10. The load weight of the electric vehicle 10 is the weight increased due to the boarding of people or the loading of goods with respect to the standard vehicle weight of the electric vehicle 10. For example, the on-vehicle weight includes the weight increased by the weight of the passenger 1 or the weight increased by the luggage loaded in the luggage compartment 14. That is, the load weight is a parameter representing the change in the weight of the entire vehicle. The weight sensor is constituted by, for example, a weighing scale embedded in the seat or the luggage compartment 14.

[0013] 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 vehicle cabin 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 provided with both an in-vehicle speaker and an out-vehicle speaker.

[0014] In addition, the electric vehicle 10 is provided 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.

[0015] 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, etc.

[0016] In addition, the electric vehicle 10 is configured to be able to tow another vehicle (the towed vehicle 20) by including a towed vehicle attachment portion 15. The electric vehicle 10 may be configured such that the towed vehicle attachment portion 15 is provided to be usable only when towing is to be performed. For example, the towed vehicle attachment portion 15 may be a component that is manually attached to the electric vehicle 10 by the user. Alternatively, the towed vehicle attachment portion 15 may normally be in a stored state and may be pulled out when towing is performed. In this case, the towed vehicle attachment portion 15 may be automatically pulled out in response to a request from the user via the HMI 12. The structure of the towed vehicle attachment portion 15 is not particularly limited. It may directly attach the towed vehicle 20 or may connect the towed vehicle 20 via a rope or the like. Also, the towed vehicle 20 may be a vehicle in various forms. For example, as the towed vehicle 20, there may be mentioned other general vehicles that have become immovable due to running out of gas or a breakdown, trailers for loading cargo, movable batteries used as external batteries for the electric vehicle 10, and the like.

[0017] In this way, the electric vehicle 10 performs towing of another vehicle (the towed vehicle 20) using the towed vehicle attachment portion 15. In relation to the performance of towing, in the present embodiment, the various sensors 11 may further include a towing information detection sensor for detecting information related to towing (towing information). The towing information detection sensor is composed of, for example, a weighing scale, a camera, etc. provided in the towed vehicle attachment portion 15. Also, in the present embodiment, the communication device 13 may include a device that performs vehicle-to-vehicle communication with the towed vehicle 20 to acquire towing information. By the towing information detection sensor and the communication device 13, information such as whether towing is being performed, the resistance force received by the towed vehicle 20, the weight of the towed vehicle 20, the vehicle type and kind of the towed vehicle 20, the attitude of the towed vehicle 20, etc. is acquired.

[0018] The vehicle management system 100 is applied to such an electric vehicle 10 and manages the electric vehicle 10. The entire vehicle management system 100 may be 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.

[0019] 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 the 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.

[0020] 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.

[0021] For example, the vehicle management system 100 has a function as 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 the speaker 70 mounted on the electric vehicle 10. Further, the vehicle management system 100 outputs the generated sounds through the speaker 70 mounted on the electric vehicle 10.

[0022] In particular, as a function of the sound management system, the vehicle management system 100 generates a "pseudo engine sound" that simulates the engine sound of an engine vehicle. Then, the vehicle management system 100 outputs the pseudo engine sound from the speaker 70 mounted on the electric vehicle 10. Note that an engine vehicle is a vehicle that has an internal combustion engine (engine) and uses the engine as a power unit (drive source) for driving.

[0023] By outputting the pseudo engine sound from the speaker 70 in the electric vehicle 10 by the vehicle management system 100, it is possible to give the driver a sense of presence as if driving an engine vehicle. Further, by enhancing the reality of the pseudo engine sound, an improvement in the driver's satisfaction can be expected. By the way, the characteristics of the engine sound generated in an actual engine vehicle vary depending on the weight of the entire vehicle that the engine is trying to drive. This is because when the weight of the entire vehicle increases, the torque required to drive the entire vehicle increases.

[0024] The vehicle management system 100 according to this embodiment focuses on changes in the weight of the entire vehicle and enables the output of a more realistic pseudo engine sound. Hereinafter, the vehicle management system 100 according to this embodiment will be described in detail regarding the function as a sound management system that outputs a pseudo engine sound.

[0025] 2 Output of pseudo engine sound FIG. 2 is a block diagram showing an example of the functional configuration of the vehicle management system 100 related to the function of outputting a pseudo engine sound. The vehicle management system 100 includes, as functional blocks, an information 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.

[0026] The information acquisition unit 110 acquires various types of information related to the electric vehicle 10. For example, the information acquisition unit 110 acquires information detected by various sensors 11 mounted on the electric vehicle 10. Also, for example, the information acquisition unit 110 acquires information input by the driver via the HMI 12. Also, for example, the information acquisition unit 110 acquires information received by the communication device 13.

[0027] In particular, the information acquisition unit 110 acquires driving state information DRV indicating the driving state of the electric vehicle 10. The driving state information DRV includes information regarding the driving operation by the driver, information regarding the running state of the electric vehicle 10, information regarding the situation around the electric vehicle 10, and the like. 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 also includes the virtual engine rotational speed Ne. Here, it is assumed that the electric vehicle 10 uses a virtual engine as a power device (drive source) 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 information acquisition unit 110 may calculate the virtual engine rotational speed Ne so as to increase as the wheel speed increases. When the electric vehicle 10 is provided with a manual mode (MT mode) described later, the information 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.

[0028] In addition, in particular, the information acquisition unit 110 acquires information on the load weight LW of the electric vehicle 10. The information acquisition unit 110 can acquire information on the load weight LW from a weight sensor.

[0029] The sound source data management unit 120 stores and manages the sound source data EVS used to generate the pseudo engine sound. In particular, the sound source data management unit 120 may store and manage a plurality of sound source data EVS (EVS-A, EVS-B, EVS-C, ···) corresponding to each of a plurality of vehicle types (A, B, C ···). That is, the sound source data management unit 120 may store and manage the sound source data EVS for each vehicle type. The sound source data EVS is typically composed of a plurality of types of sound source data. The plurality of types of sound source data includes, for example, sound source data of sounds caused by engine combustion (for low engine speeds, medium engine speeds, high engine speeds), sound source data of sounds caused by drive systems such as gears (for low engine speeds, medium engine speeds, high engine speeds), sound source data of noise sounds, sound source data of event sounds (e.g., rattling sounds, engine stall sounds), etc. Each sound source data is generated in advance through simulations based on the engine model and vehicle model of the engine vehicle. Each sound source data is configured to be able to flexibly adjust at least one of the sound pressure and frequency of the sound.

[0030] The engine sound generation unit 130 (engine sound simulator) is a simulator that generates a pseudo engine sound. The engine sound generation unit 130 reads the sound source data EVS from the sound source data management unit 120. When the sound source data management unit 120 stores and manages the sound source data EVS for each vehicle type, the engine sound generation unit 130 selects and reads one of the plurality of sound source data EVS. At this time, the engine sound generation unit 130 may be configured to select and read the sound source data EVS corresponding to the vehicle type specified by the driver among the plurality of vehicle types. The driver can specify the vehicle type via the HMI 12. The engine sound generation unit 130 generates a pseudo engine sound by combining one or more sound source data included in the sound source data EVS.

[0031] The engine sound generation unit 130 includes a basic sound generation unit 131, a correction specification generation unit 132, and a correction unit 133. The engine sound generation unit 130 acquires the driving state information DRV and the loaded weight LW of the electric vehicle 10 from the information acquisition unit 110.

[0032] The basic sound generation unit 131 generates a basic pseudo engine sound ES0 corresponding to the driving state (virtual engine rotational speed Ne and vehicle speed) of the electric vehicle 10 based on the driving state information DRV. The method for generating the basic pseudo engine sound ES0 is not particularly limited in this embodiment. For example, the basic sound generation unit 131 may be configured to generate the basic pseudo engine sound ES0 by a well-known engine simulator employed in a game or the like. Also, for example, the basic sound generation unit 131 may generate the basic pseudo engine sound ES0 by increasing or decreasing the frequency in proportion to the virtual engine rotational speed Ne and increasing or decreasing the sound pressure in proportion to the virtual engine torque according to a virtual engine rotational speed Ne - frequency map and a virtual engine torque - sound pressure map. The basic pseudo engine sound ES0 generated by the basic sound generation unit 131 is transmitted to the correction unit 133.

[0033] The correction specification generation unit 132 generates a correction specification (correction specification RS) for correcting the basic pseudo engine sound ES0 to be executed in the correction unit 133 described later. The correction specification RS indicates, for example, a correction value for sound pressure, a correction value for frequency, correction of timbre, sound source data to be added, and the like. In particular, in the present embodiment, the correction specification generation unit 132 generates the correction specification RS based at least on the loaded weight LW of the electric vehicle 10. The correction specification RS generated at this time reproduces the change in the engine sound caused by the change in the weight of the entire vehicle in an actual engine vehicle. Typically, the correction specification generation unit 132 generates the correction specification RS so as to increase the sound pressure correction value as the loaded weight LW increases. This reproduces the increase in the sound pressure of the engine sound due to the increase in the torque required to drive the entire vehicle. The correction specification generation unit 132 can determine the sound pressure correction value for the loaded weight LW using a map of the loaded weight LW - sound pressure correction value and generate the correction specification RS. FIG. 2 shows an example of a map of the loaded weight LW - sound pressure correction value. In addition, the correction specification generation unit 132 may determine the sound source data to be added to reproduce the change in the engine sound in an actual engine vehicle according to the loaded weight LW and generate the correction specification RS. The sound source data to be added may be included in the sound source data EVS read by the engine sound generation unit 130. For example, the sound source data EVS may include a plurality of sound source data recorded for each loaded weight when the loaded weight is changed in the corresponding actual engine vehicle. The correction specification RS generated by the correction specification generation unit 132 is transmitted to the correction unit 133.

[0034] The correction unit 133 corrects the basic pseudo engine sound ES0 according to the correction specification RS. For example, the correction unit 133 corrects the sound pressure of the basic pseudo engine sound ES0 according to the sound pressure correction value indicated by the correction specification RS. Also, for example, the correction unit 133 adds the sound source data indicated by the correction specification RS to the basic pseudo engine sound ES0.

[0035] The pseudo engine sound generated by the engine sound generation unit 130 is the basic pseudo engine sound corrected by the correction unit 133. The engine sound generation unit 130 outputs engine sound data ES, which is data indicating this pseudo engine sound. By the way, as described above, the correction specification RS is generated based on at least the load weight LW of the electric vehicle 10. Therefore, the pseudo engine sound generated by the engine sound generation unit 130 reflects the information of the load weight LW. Typically, the pseudo engine sound generated by the engine sound generation unit 130 has a higher sound pressure as the load weight LW increases.

[0036] The sound output control unit 140 receives the engine sound data ES generated by the engine sound generation unit 130. Then, based on the engine sound data ES, the sound output control unit 140 outputs a pseudo engine sound through the speaker 70.

[0037] FIG. 3 is a flowchart showing an example of a processing flow of processing executed by the vehicle management system 100 regarding the function of outputting a pseudo engine sound based on the above-described functional configuration. The processing flow shown in FIG. 3 is repeatedly executed at a predetermined processing cycle.

[0038] First, in step S110, the vehicle management system 100 acquires driving state information DRV.

[0039] Next, in step S120, based on the driving state information DRV, the vehicle management system 100 generates a basic pseudo engine sound ES0 corresponding to the driving state of the electric vehicle 10.

[0040] Next, in step S130, the vehicle management system 100 acquires the load weight LW of the electric vehicle 10.

[0041] Next, in step S140, the vehicle management system 100 generates a correction specification RS based on at least the load weight LW.

[0042] Next, in step S150, the vehicle management system 100 generates a pseudo engine sound by correcting the basic pseudo engine sound ES0 according to the correction specification RS.

[0043] Then, in step S160, the vehicle management system 100 outputs the generated basic pseudo engine sound from the speaker 70.

[0044] As described above, the vehicle management system 100 according to the present embodiment is configured. According to the vehicle management system 100 according to the present embodiment, the pseudo engine sound output from the speaker 70 changes according to the payload LW of the electric vehicle 10. The payload LW is a parameter representing the change in the weight of the entire vehicle. Therefore, the pseudo engine sound can reproduce the change in the engine sound due to the change in the weight of the entire vehicle in an actual engine vehicle. In this way, according to the vehicle management system 100 according to the present embodiment, a more realistic pseudo engine sound can be output. Consequently, an improvement in driver satisfaction can be expected.

[0045] 2.1 Sound management considering the towing implementation status The electric vehicle 10 according to the present embodiment is configured to be able to tow other vehicles (the towed vehicle 20). When the electric vehicle 10 performs towing, the weight of the entire vehicle that the drive source attempts to drive increases by the weight of the towed vehicle 20. Consequently, the torque required to drive the entire vehicle increases. Therefore, when assuming an actual engine vehicle, it is conceivable that the characteristics of the pseudo engine sound change when towing is performed. On the other hand, the weight of the towed vehicle 20 does not appear in the payload LW. Therefore, the vehicle management system 100 according to the present embodiment can be configured to generate a pseudo engine sound output from the speaker 70 while further considering the towing implementation status.

[0046] FIG. 4 is a block diagram showing an example of the functional configuration of the vehicle management system 100 when considering the implementation status of towing. In the example shown in FIG. 4, in addition to the functional blocks described in FIG. 3, a towing implementation status determination unit 150 is further included. This functional block is realized, for example, by the cooperation of the processor 101 and the storage device 102.

[0047] The towing implementation status determination unit 150 acquires information regarding towing (towing information TIN) via the information acquisition unit 110. Then, the towing implementation status determination unit 150 determines the towing implementation status (towing implementation status TS) based on the towing information TIN. The towing implementation status TS includes at least information on whether or not the electric vehicle 10 is performing towing. The towing implementation status TS may further include the weight of the towed vehicle 20. In addition, the towing implementation status TS may include information such as the resistance force received by the towed vehicle 20, the vehicle type and kind of the towed vehicle 20, and the attitude of the towed vehicle 20. The towing implementation status determination unit 150 transmits the towing implementation status TS to the correction specification generation unit 132.

[0048] When the correction specification generation unit 132 receives the towing implementation status TS, it generates a correction specification RS based on the towing implementation status TS in addition to the loaded weight LW. The correction specification generation unit 132 generates the correction specification RS so as to increase the sound pressure correction value at least when the electric vehicle 10 is performing towing. Thereby, it is possible to reproduce the increase in the sound pressure of the engine sound due to the increase in the torque required to drive the entire vehicle by the towed vehicle 20. Further, the correction specification generation unit 132 may generate the correction specification RS so as to increase the sound pressure correction value as the weight of the towed vehicle 20 increases. Alternatively, the correction specification generation unit 132 may determine the sound pressure correction value according to the vehicle type and kind of the towed vehicle and generate the correction specification RS. In this case, the sound pressure correction value is determined, for example, from the weight specifications of that vehicle type and kind.

[0049] The correction specification generation unit 132 may separately generate a correction specification RS based on the loading weight LW and a correction specification RS based on the towing execution status TS, or may generate them together. For example, when the electric vehicle 10 is performing towing, the correction specification generation unit 132 may determine a sound pressure correction value according to the sum of the loading weight LW and the weight of the towed vehicle 20 and generate the correction specification RS.

[0050] The other functional blocks are the same as the functions described in FIG. 2.

[0051] As described above, by providing the functional configuration of the vehicle management system 100, the pseudo engine sound output from the speaker 70 reflects the towing execution status. Typically, when the electric vehicle 10 is performing towing, the sound pressure of the pseudo engine sound increases. In this way, the vehicle management system 100 can be configured to output a more realistic pseudo engine sound in relation to the execution of towing.

[0052] 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: Conventional Vehicle). 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 manual operation of the driver. Therefore, 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.

[0053] On the one 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 MT vehicles. Also, in order for the driver to obtain a driving feeling like that of an MT vehicle, a pseudo shifter imitating a shift member used for the shifting operation of an MT vehicle can be provided in the electric vehicle. By these means, it becomes possible to simulate an MT vehicle in an electric vehicle.

[0054] That is, an electric vehicle controls the output of an electric motor so as to simulate the driving characteristics (torque characteristics) peculiar to MT vehicles. 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 simulates an MT vehicle and changes the driving characteristics (torque characteristics). Thereby, 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 manual shifting operation of an MT vehicle is referred to as the "manual mode" or the "MT mode".

[0055] 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 an MT vehicle but also the engine sound of an MT vehicle is reproduced, the satisfaction of the driver who pursues reality is enhanced.

[0056] Hereinafter, a configuration example of the electric vehicle 10 provided with the manual mode (MT mode) will be described.

[0057] FIG. 5 is a block diagram showing a configuration example of a 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.

[0058] The electric vehicle 10 includes an accelerator pedal 22 for a driver to input an acceleration request for the electric vehicle 10. The accelerator pedal 22 is provided with an accelerator position sensor 32 for detecting the accelerator opening.

[0059] The electric vehicle 10 includes a sequential shifter 24. The sequential shifter 24 is a pseudo shifter modeled after 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.

[0060] 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 emits an upshift signal when pulled forward, and the downshift switch emits a downshift signal when pulled forward.

[0061] 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 output a downshift signal by tilting the shift lever backward.

[0062] The wheels of the electric vehicle 10 are provided with wheel speed sensors 36. The wheel speed sensors 36 are used as vehicle speed sensors for detecting the vehicle speed of the electric vehicle 10. Further, the electric motor 44 is provided with a rotational speed sensor 38 for detecting its rotational speed.

[0063] The electric vehicle 10 includes 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 a plurality of ECUs.

[0064] 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.

[0065] 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 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.

[0066] 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.

[0067] 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. 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.

[0068] 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.

[0069] 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 for the calculation of the virtual engine output torque.

[0070] 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 for the calculation of the torque transmission gain.

[0071] 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 rotation speed in the engine model. To calculate the slip ratio, a map in which the slip ratio is given for the virtual clutch opening can be used, similar to the torque transmission gain.

[0072] 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. To calculate the gear ratio, a map defining the relationship between the gear ratio and the virtual gear stage is used. 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, producing the feel of a vehicle equipped with a stepped transmission.

[0073] And 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.

[0074] The control device 50 converts the drive wheel torque calculated in the MT vehicle model into the required motor torque. The required motor torque is the motor torque necessary to achieve the drive wheel torque calculated in the MT vehicle model. To convert the drive wheel torque into 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 through the control of the inverter 42 according to the required motor torque.

[0075] 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). FIG. 5 shows an example of the output characteristics C10 of the electric motor 44 realized in the manual mode. In the manual mode, output characteristics C10 that simulate the torque characteristics of the MT vehicle can be realized according to the virtual gear stages (1st, 2nd, ···, 6th) set by the sequential shifter 24.

[0076] In the above-described configuration example, the case where the simulated shifter is configured by the sequential shifter 24 has been described. The configuration of the simulated shifter may adopt other forms assumed in an actual MT vehicle. 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.

[0077] 3.1 Torque Control Considering Payload As described above, by the control device 50 executing torque control of the electric motor 44 in the manual mode, the driver of the electric vehicle 10 can drive the electric vehicle 10 with torque characteristics as if driving an MT vehicle. By the way, in an actual MT vehicle, when the weight of the entire vehicle increases, the torque required to drive the entire vehicle increases. For this reason, when the payload increases, the driver may feel that the driving force is not as expected. This is a factor that reduces the driver's satisfaction in the manual mode.

[0078] Therefore, the control device 50 may be configured to change the output characteristic C10 of the electric motor 44 to be realized according to the loading weight LW of the electric vehicle 10 in the manual mode.

[0079] Refer to FIG. 5. Information on the loading weight LW of the electric vehicle 10 is input from the weight sensor 35 to the manual mode torque calculation unit 56 of the control device 50. The manual mode torque calculation unit 56 changes the output characteristic C10 of the electric motor 44 according to the loading weight LW. Typically, as the loading weight LW increases, the output characteristic C10 is changed so that the motor torque with respect to the vehicle speed (motor rotation speed) is increased in the low speed range. FIG. 6 is a conceptual diagram showing an example of the change in the output characteristic C10 when the loading weight LW increases. As shown in FIG. 6, the output characteristic C10b when the loading weight LW increases has a characteristic that allows a higher motor torque to be obtained in the low speed range compared to the output characteristic C10a before the loading weight LW increases. Note that the change in the output characteristic C10 according to the increase in the loading weight LW may be performed stepwise or continuously.

[0080] By changing the output characteristic C10 according to the loading weight LW in the manual mode in this way, it is possible to suppress the driver from feeling a lack of driving force when the loading weight LW increases. Also, when the loading weight LW is small, the driver can enjoy driving with torque that can cover from the low speed range to the high speed range. In this way, the satisfaction of the driver can be improved.

Description of Reference Numerals

[0081] 10 Electric vehicle, 44 Electric motor, 50 Control device, 70 Speaker, 100 Vehicle management system, 101 Processor, 102 Storage 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 a pseudo engine sound and output the pseudo engine sound from a speaker mounted on the electric vehicle, wherein the one or more processors acquire the payload of the electric vehicle, and are configured to change the pseudo engine sound according to the payload An electric vehicle.

2. The electric vehicle according to claim 1, wherein the one or more processors are configured to increase the sound pressure of the pseudo engine sound as the payload increases. An electric vehicle.

3. The electric vehicle according to claim 1, configured to be able to tow another vehicle, wherein the one or more processors judge the towing situation by the electric vehicle, and are configured to increase the sound pressure of the pseudo engine sound when the electric vehicle is towing. An electric vehicle.

4. The electric vehicle according to any one of claims 1 to 3, further comprising an accelerator pedal, a pseudo shifter imitating an operating member used for gear shifting of a manual transmission vehicle, and a control device that executes torque control for controlling the motor torque output by the electric motor, wherein the torque control includes a manual mode in which the motor torque is changed in response to the operating states of the accelerator pedal and the pseudo shifter. An electric vehicle.

5. The electric vehicle according to claim 4, wherein the control device is configured to change the output characteristics of the electric motor so that the motor torque increases in a low speed range as the payload increases in the manual mode. An electric vehicle. ​ ​ ​ ​ ​

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