Electric vehicle

Abstract

To provide a technique which enables a driver of a vehicle to be informed about the driver's condition, when driving in an MT mode.SOLUTION: An electric vehicle 1 comprises: a driver monitor 2 which estimates a driver's condition indicating a condition of a driver 4; and one or multiple processors 60 that generate a simulated engine sound and output the simulated engine sound through an on-board speaker 3. The one or multiple processors 60 vary the simulated engine sound, based on the driver's condition, in an MT mode simulating an MT vehicle.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to an electric vehicle that uses an electric motor as a power unit for running. [Background technology]

[0002] Patent Document 1 discloses a technology for generating, in the vehicle cabin, a virtual sound that is generated when a virtual vehicle equipped with a virtual engine as a driving force source is driven. In this conventional technology, the load on the virtual engine when the virtual engine is controlled based on the driving operation is estimated, and the virtual sound that is generated in the vehicle cabin when the virtual engine is controlled to achieve the estimated load is estimated. Furthermore, in the conventional technology, an acoustic device is controlled so that the estimated virtual sound is generated in the vehicle cabin of a real vehicle. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2022-036005 [Patent Document 2] JP 2002-008159 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, when driving an electric vehicle in manual mode (MT mode), the driver has to perform more driving operations than when driving in automatic mode (AT mode). When driving an electric vehicle long distances in MT mode, the driver may become fatigued or stressed. Depending on the driver's condition, driving safety may not be ensured.

[0005] One object of the present disclosure is to provide a technique that can inform the driver of the vehicle of the driver's state while driving in MT mode. [Means for solving the problem]

[0006] One aspect of the present disclosure relates to an electric vehicle that uses an electric motor as a power unit for running and has a manual transmission mode that simulates a manual transmission vehicle. The electric vehicle includes a driver monitor that estimates a driver state that indicates the state of the driver, and one or more processors that are configured to generate a pseudo engine sound and output the pseudo engine sound through an in-vehicle speaker. In the manual transmission mode, the one or more processors change the pseudo engine sound based on the driver state. Effect of the Invention

[0007] According to the present disclosure, the driver's state is estimated, and in the MT mode, the pseudo engine sound is changed based on the driver's state. This makes it possible to inform the driver of the vehicle's state, which is expected to lead to the driver taking a break. Therefore, driving safety is improved. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram for explaining an overview of an electric vehicle according to an embodiment. [Diagram 2] FIG. 2 is a block diagram showing an example of the functions of a processor; [Diagram 3] 1 is a block diagram showing an example of the configuration of a power control system of an electric vehicle; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] An electric vehicle according to an embodiment of the present disclosure will be described with reference to the accompanying drawings.

[0010] 1. Overview FIG. 1 is a diagram for explaining an overview of an electric vehicle 1 (hereinafter simply referred to as vehicle 1) according to an embodiment. Vehicle 1 uses an electric motor as a power unit for traveling. Vehicle 1 also has an MT mode that simulates a manual transmission vehicle. The configuration of a power control system for vehicle 1 will be described in detail later.

[0011] As shown in FIG. 1, a vehicle 1 includes a driver monitor 2, one or more in-vehicle speakers 3 (hereinafter simply referred to as speakers 3), and an information processing device 10. The driver monitor 2 estimates a driver state indicating the state of a driver 4. The driver monitor 2 includes a sensor and a control device that estimates the driver state based on information detected by the sensor. Examples of the sensor include an in-vehicle camera that captures images inside the vehicle and a smart watch that detects biological information. The biological information is heart rate, etc. The driver state will be described in detail later. The speaker 3 is an in-vehicle speaker that outputs sound inside the vehicle.

[0012] The information processing device 10 generates a pseudo engine sound to be output from a speaker 3. The information processing device 10 is, for example, an ECU (Electronic Control Unit), a tablet PC, or the like. The information processing device 10 includes one or more processors 60 (hereinafter simply referred to as processor 60) and one or more storage devices 70 (hereinafter simply referred to as storage devices 70). The processor 60 executes various types of processing. An example of the processor 60 is a CPU (Central Processing Unit). The storage device 70 stores various types of information required for processing by the processor 60. An example of the storage device 70 is a volatile memory, a non-volatile memory, a HDD (Hard Disk Drive), an SSD (Solid State Drive), or the like.

[0013] The sound generation program (not shown) is a computer program executed by the processor 60. The processor 60 may execute the sound generation program to realize various functions of the information processing device 10. The sound generation program may be stored in the storage device 70, or may be recorded in a computer-readable storage medium.

[0014] The various information stored in the storage device 70 includes sound source data 71 and driving state information 72.

[0015] The sound source data 71 is used to generate a pseudo engine sound to be output from the speaker 3. The driving state information 72 indicates the driving state of the vehicle 1. Examples of the driving state of the vehicle 1 include a virtual engine rotation speed, a speed, and the like. The virtual engine rotation speed is the rotation speed of a virtual engine when it is assumed that the vehicle 1 is driven by the virtual engine. For example, the virtual engine rotation speed is calculated based on the rotation speed of the wheels, the overall reduction ratio, and the slip ratio of the virtual clutch. The speed is detected by a sensor mounted on the vehicle 1.

[0016] Consider a case where a pseudo engine sound is output from the speaker 3 in the vehicle 1. In this case, multiple types of basic sound source data for generating the pseudo engine sound are prepared as the sound source data 71. The multiple types of basic sound source data include, for example, sound source data of sounds caused by engine combustion (for low revolutions, medium revolutions, and high revolutions), sound source data of sounds caused by a drive system such as gears (for low revolutions, medium revolutions, and high revolutions), sound source data of noise sounds, sound source data of event sounds, and the like. The information processing device 10 generates a pseudo engine sound according to the driving state of the vehicle 1 by combining one or more basic sound source data. The method of generating the pseudo engine sound is not particularly limited. For example, the pseudo engine sound may be generated by a well-known pseudo engine sound simulator adopted in games and the like. In addition, the type of engine vehicle to be simulated may be specified by the driver 4.

[0017] The outline of the engine pseudo sound generation process by the processor 60 (information processing device 10) according to this embodiment is as follows. The processor 60 generates an engine pseudo sound and outputs the engine pseudo sound through the speaker 3. In the MT mode, the processor 60 changes the engine pseudo sound based on the driver state estimated by the driver monitor 2.

[0018] According to the present disclosure, the driver's state is estimated, and in the MT mode, the pseudo engine sound is changed based on the driver's state. This makes it possible to inform the driver of the vehicle of the driver's state, which is expected to lead to the driver taking a break. Therefore, driving safety is improved.

[0019] 2. Specific examples 2-1. Function examples 2 is a block diagram showing an example of functions of the processor 60. The processor 60 includes, as functional blocks, a variety of information acquisition unit 61, an engine pseudo sound generation unit 62, and a generated sound output unit 63.

[0020] The various information acquisition unit 61 acquires the sound source data 71 and the driving state information 72 from the storage device 70. The various information acquisition unit 61 also acquires the information on the driver's state from the driver monitor 2.

[0021] Consider the driver state acquired from the driver monitor 2. The driver state is expressed by at least one of, for example, a fatigue level, a stress level, and a sleepiness level. The fatigue level, the stress level, and the sleepiness level may be estimated in the driver monitor 2 based on an analysis result of a face image captured by an in-vehicle camera (e.g., a rate of change in the number of blinks of the driver 4, an eye opening / closing degree, and a frequency of yawning), or may be estimated based on biological information detected by a smart watch (e.g., a heart rate). For example, when a rate of change in the number of blinks of the driver 4 is equal to or greater than a threshold value, the driver monitor 2 may estimate that the fatigue level is high. As another example, when the heart rate of the driver 4 is equal to or greater than a reference value, the driver monitor 2 may estimate that the stress level is high. As yet another example, when the frequency of yawning of the driver 4 is estimated to be equal to or greater than a reference level, the driver monitor 2 may estimate that the sleepiness level is high.

[0022] The pseudo engine sound generating unit 62 generates a pseudo engine sound based on the sound source data 71 and the driving state information 72, and changes the pseudo engine sound based on the information on the driver state. Specifically, when at least one of the driver state, ie, fatigue level, stress level, and drowsiness level, is higher than a threshold, the pseudo engine sound generating unit 62 changes the pseudo engine sound. In this case, the pseudo engine sound is changed to a conspicuous sound that the driver 4 notices. Examples of conspicuous sounds that the driver 4 notices include sounds that stimulate the driver 4 (e.g., sounds with high sound pressure, heavy bass), sounds that make the driver 4 uncomfortable (e.g., sounds in a frequency band that people find uncomfortable, noise sounds, loud sounds), and the like. Therefore, in the process of changing the pseudo engine sound, the pseudo engine sound generating unit 62 executes at least one process among, for example, sound frequency control, sound pressure control, sound volume control, and a process of regenerating the pseudo engine sound (e.g., adding noise sounds). The process of changing the pseudo engine sound may be effective only in the MT mode.

[0023] The generated sound output unit 63 outputs the pseudo engine sound through the speaker 3 based on the data of the pseudo engine sound generated by the pseudo engine sound generation unit 62 .

[0024] 2-2.Vehicle configuration examples 2-2-1. First configuration example Case A in Fig. 3 is a block diagram showing a first configuration example of a power control system for vehicle 1. Vehicle 1 is equipped with electric motor 44, battery 46, and inverter 42. Electric motor 44 is a power device for traveling. Vehicle 1 is a battery electric vehicle (BEV) that runs on electric energy stored in battery 46. Inverter 42 converts DC power input from battery 46 during acceleration into drive power for electric motor 44.

[0025] The vehicle 1 is equipped with an accelerator pedal 22 for the driver to input an acceleration request to the vehicle 1. The accelerator pedal 22 is provided with an accelerator position sensor 32 for detecting the accelerator opening degree.

[0026] The vehicle 1 is equipped with a sequential shifter 24. The sequential shifter 24 may be a paddle-type shifter or a lever-type pseudo shifter. The paddle-type shifter and the lever-type pseudo shifter are dummies that are different from the actual paddle-type shifter or shifter.

[0027] The paddle-type shifter is equipped with an upshift switch and a downshift switch that determine the operation position. When the upshift switch is pulled toward the driver, it generates an upshift signal 34u, and when the downshift switch is pulled toward the driver, it generates a downshift signal 34d.

[0028] On the other hand, the lever-type pseudo shifter is configured to output an upshift signal 34u when the shift lever is tilted forward, and output a downshift signal 34d when the shift lever is tilted backward. The lever-type pseudo shifter is connected to the motor control device 50 via an in-vehicle network.

[0029] Wheel speed sensors 36 are provided on the wheels 26 of the vehicle 1. The wheel speed sensors 36 are used as vehicle speed sensors for detecting the speed of the vehicle 1. In addition, the electric motor 44 is provided with a rotation speed sensor 38 for detecting the rotation speed thereof.

[0030] The vehicle 1 is equipped with a motor control device 50. The motor control device 50 is a device that controls the electric motor 44 by PWM control of the inverter 42. The motor control device 50 processes various input signals shown in case A of FIG. 3, and calculates a motor torque command value for PWM controlling the inverter 42.

[0031] The motor control device 50 is an ECU mounted on the vehicle 1. The motor control device 50 may be a part of the information processing device 10, or may be independent of the information processing device 10. The above-mentioned driving state information 72 is generated by the motor control device 50, for example.

[0032] The motor control device 50 includes an automatic mode and a manual mode as control modes. The automatic mode is a control mode for driving the vehicle 1 as a general electric vehicle. 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 vehicle 1 as if it were a manual transmission vehicle. The manual mode is programmed to change the output characteristics of the electric motor 44 in response to the operation of the accelerator pedal 22 in response to upshifting and downshifting operations of the sequential shifter 24.

[0033] In the automatic mode, the motor control device 50 uses a map that determines the motor torque from the accelerator opening and the rotational speed of the electric motor 44, and outputs the motor torque corresponding to the signal of the accelerator position sensor 32 and the signal of the rotational speed sensor 38. Therefore, in the automatic mode, even if the driver operates the sequential shifter 24, the operation is not reflected in the motor torque.

[0034] The motor control device 50 includes a vehicle model. The vehicle model refers to a model that calculates the drive wheel torque that should be obtained by operating the accelerator pedal 22 and the sequential shifter 24 when the vehicle 1 is assumed to be a manual transmission vehicle. In the manual mode, the motor control device 50 calculates the drive wheel torque, and converts the calculated drive wheel torque into a motor torque using a reduction ratio from the output shaft of the electric motor 44 to the drive wheels.

[0035] The vehicle model is composed of an engine model, a clutch model, and a transmission model. The engine model calculates a virtual engine rotation speed and a virtual engine output torque. The virtual engine rotation 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 rotation speed and the accelerator opening. A map that specifies the relationship between the accelerator opening, the virtual engine rotation speed, and the virtual engine output torque is used to calculate the virtual engine output torque.

[0036] 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 that defines the relationship between the virtual clutch opening and the torque transmission gain is used to calculate the torque transmission gain.

[0037] The clutch model uses the torque transmission gain to calculate the clutch output torque. 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 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, as in the case of the torque transmission gain.

[0038] The transmission model calculates the gear ratio (speed ratio). The gear ratio is determined by the virtual gear stage in the virtual transmission. A map that specifies the relationship between the gear ratio and the virtual gear stage is used to calculate the gear ratio. The transmission model calculates the transmission output torque using the gear ratio obtained from the map and the clutch output torque. The transmission output torque changes discontinuously as the gear ratio is switched. This discontinuous change in the transmission output torque generates a gear shift shock, creating the feeling that a vehicle equipped with a stepped transmission is equipped.

[0039] 2-2-2. Second configuration example Case B in Fig. 3 is a block diagram showing a second configuration example of the power control system of the vehicle 1. In the second configuration example, a pseudo shift lever 27 and a pseudo clutch pedal 28 are provided instead of the sequential shifter 24 provided in the first configuration example. The pseudo shift lever 27 and the pseudo clutch pedal 28 are dummies that are different from an actual shift lever and clutch pedal.

[0040] The pseudo shift lever 27 has positions corresponding to each gear stage, for example, 1st, 2nd, 3rd, 4th, 5th, 6th, reverse, and neutral. The pseudo shift lever 27 has a shift position sensor 27a that detects the gear stage by determining which position the pseudo shift lever 27 is in. The shift position sensor 27a is connected to the motor control device 50 by an in-vehicle network.

[0041] The pseudo clutch pedal 28 is provided with a clutch position sensor 28a for detecting the amount of depression of the pseudo clutch pedal 28. The clutch position sensor 28a is connected to the motor control device 50 via an in-vehicle network.

[0042] The motor control device 50 calculates a motor torque command value to be output to the inverter 42 based on input signals from the shift position sensor 27a and the clutch position sensor 28a. The motor control device 50 is programmed to change the output of the electric motor 44 in response to the operation of the accelerator pedal 22 in accordance with the operation of the pseudo clutch pedal 28 and the pseudo shift lever 27 in the manual mode.

[0043] In the vehicle model provided in the motor control device 50, the virtual clutch opening is replaced with the depression amount of the pseudo clutch pedal 28 detected by the clutch position sensor 28a. Also, the virtual gear stage is determined by the position of the pseudo shift lever 27 detected by the shift position sensor 27a.

[0044] 3. Other embodiments Even if the driver's state does not satisfy the condition for changing the pseudo engine sound, the processor 60 may change the pseudo engine sound after a certain distance has been traveled. Alternatively, when changing the pseudo engine sound, the processor 60 may issue a notification to prompt a change from the MT mode to the AT mode. This is expected to lead to a reduction in the driver's rest and the burden of driving operations, and to improve driving safety. [Explanation of symbols]

[0045] 1...vehicle, 2...driver monitor, 3...speaker, 4...driver, 10...information processing device, 60...processor, 70...storage device, 71...sound source data, 72...driving state information

Claims

[Claim 1] An electric vehicle that uses an electric motor as a power unit for driving and has an MT mode that simulates an MT vehicle, A driver monitor for estimating a driver state indicative of a driver's state; one or more processors configured to generate a simulated engine sound and output the simulated engine sound through an on-board speaker; The one or more processors are configured to change the pseudo engine sound based on the driver state in the MT mode. An electric vehicle characterized by

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