Active sound effect generation device and active sound effect generation method

Abstract

The invention provides an active sound effect generation device and an active sound effect generation method. An active sound effect generation device (10) that causes a speaker (12) to output a sound effect into a cabin of a vehicle driven by an electric motor, the active sound effect generation device (10) being provided with: a signal generation unit (34) that generates a first sound effect signal, which is a signal for causing the speaker to output the sound effect; a gain setting unit (35) that sets a gain in accordance with the amount of regeneration of the motor; the output unit (30) outputs, to the speaker, a second sound effect signal generated by multiplying the first sound effect signal by the gain. Therefore, a better active sound effect generating device can be provided.

Description

Technical Field

[0001] The present invention relates to an active sound effect generation device and an active sound effect generation method. Background Art

[0002] In Japanese Patent Publication No. 6371328, an active sound effect generation device is disclosed. The active sound effect generation device generates a sound effect in the passenger compartment of a vehicle having an electric motor. Summary of the Invention

[0003] A better active sound effect generation device and an active sound effect generation method are desired.

[0004] An object of the present invention is to solve the above technical problems.

[0005] A first aspect of the present invention is an active sound effect generation device that outputs a sound effect from a speaker into the passenger compartment of a vehicle driven by an electric motor. The active sound effect generation device includes a signal generation unit, a gain setting unit, and an output unit. The signal generation unit generates a first sound effect signal for causing the speaker to output the sound effect. The gain setting unit sets a gain according to the regeneration amount of the electric motor. The output unit outputs a second sound effect signal generated by multiplying the first sound effect signal by the gain to the speaker.

[0006] A second aspect of the present invention is an active sound effect generation method that outputs a sound effect from a speaker into the passenger compartment of a vehicle driven by an electric motor. The active sound effect generation method generates a first sound effect signal for causing the speaker to output the sound effect, sets a gain according to the regeneration amount of the electric motor, and outputs a second sound effect signal generated by multiplying the first sound effect signal by the gain to the speaker.

[0007] According to the present invention, a better active sound effect generation device and an active sound effect generation method can be provided.

[0008] The above objects, features, and advantages should be easily understood from the following description of the embodiments with reference to the drawings. Brief Description of the Drawings

[0009] Figure 1 It is a block diagram showing the structure of an active sound effect generation device in an embodiment.

[0010] Figure 2 It is a schematic diagram showing the frequency band of the linked sound and the frequency band of the background sound.

[0011] Figure 3It is a graph showing the frequency components of the motor sound and the frequency components of the synthesized sound.

[0012] Figure 4 It is a block diagram showing the structure of the first linked sound signal generation unit in one embodiment.

[0013] Figure 5 It is a mapping diagram of the gain in one embodiment.

[0014] Figure 6 It is a mapping diagram of the gain in one embodiment.

[0015] Figure 7 It is a mapping diagram of the gain in one embodiment.

[0016] Figure 8 It is a mapping diagram of the gain in one embodiment.

[0017] Figure 9 It is a mapping diagram of the gain in one embodiment.

[0018] Figure 10 It is a block diagram showing the structure of the first background sound signal generation unit in one embodiment.

[0019] Figure 11 It is a flowchart of the sound effect generation process executed in the active sound effect generation device in one embodiment. Detailed Embodiments

[0020] In a vehicle having an engine as a drive source, when the vehicle is traveling on a downhill road surface, engine braking is sometimes applied. When engine braking is applied, the engine speed increases and the engine sound echoing in the passenger compartment becomes louder.

[0021] In a vehicle having an electric motor as a drive source, regenerative braking of the electric motor is used instead of engine braking. When regenerative braking is applied, sounds such as engine sound do not echo in the vehicle, and thus, it is difficult for the occupants to recognize that regenerative braking is being applied.

[0022] In the active sound effect generation device of the present invention, it is possible to make the occupants recognize that regenerative braking is being applied.

[0023] 〔One Embodiment〕 [Structure of Active Sound Effect Generation Device] Figure 1FIG. 0 is a block diagram showing the configuration of an active sound generation device 10 in an embodiment. The active sound generation device 10 is mounted on a vehicle driven by an electric motor. A vehicle driven by an electric motor refers to a BEV (Battery Electric Vehicle), an HEV (Hybrid Electric Vehicle), a PHEV (Plug-in Hybrid Electric Vehicle), an FCEV (Fuel Cell Electric Vehicle), etc. Hereinafter, a vehicle driven by an electric motor will be referred to as an electric vehicle.

[0024] The active sound generation device 10 is a device that outputs a sound effect that changes according to the rotational speed of the electric motor through a speaker 12 provided in the passenger compartment of the electric vehicle. The sound effect enhances the attractiveness of the electric vehicle to the occupants.

[0025] The active sound generation device 10 includes an arithmetic unit 14 and a storage unit 16. The arithmetic unit 14 is, for example, a processor such as a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit).

[0026] The arithmetic unit 14 functions as a first linked sound signal generation unit 18, a second linked sound signal generation unit 20, a first background sound signal generation unit 22, a second background sound signal generation unit 24, a third background sound signal generation unit 26, a fourth background sound signal generation unit 28, and an output unit 30. The first linked sound signal generation unit 18, the second linked sound signal generation unit 20, the first background sound signal generation unit 22, the second background sound signal generation unit 24, the third background sound signal generation unit 26, the fourth background sound signal generation unit 28, and the output unit 30 are implemented by executing a program stored in the storage unit 16 in the arithmetic unit 14.

[0027] At least a part of the first associated sound signal generation unit 18, the second associated sound signal generation unit 20, the first background sound signal generation unit 22, the second background sound signal generation unit 24, the third background sound signal generation unit 26, the fourth background sound signal generation unit 28, and the output unit 30 can also be implemented by an integrated circuit such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field-Programmable Gate Array). At least a part of the first associated sound signal generation unit 18, the second associated sound signal generation unit 20, the first background sound signal generation unit 22, the second background sound signal generation unit 24, the third background sound signal generation unit 26, the fourth background sound signal generation unit 28, and the output unit 30 can also be implemented by an electronic circuit including discrete devices.

[0028] The storage unit 16 is composed of a volatile memory (not shown) and a non-volatile memory (not shown) which are computer-readable storage media. The volatile memory is, for example, a RAM (Random Access Memory) or the like. The non-volatile memory is, for example, a ROM (Read Only Memory), a flash memory, or the like. Data and the like are stored in the volatile memory, for example. Programs, tables, maps, and the like are stored in the non-volatile memory, for example.

[0029] At least a part of the storage unit 16 can also be provided in the above-mentioned processor, integrated circuit, etc. At least a part of the storage unit 16 can also be mounted on a device connected to the active sound effect generation device 10 through a network.

[0030] Sound source data is stored in the storage unit 16. The sound source data is information on a sound composed of a plurality of frequency components in a first frequency band. Hereinafter, the sound composed of a plurality of frequency components in the first frequency band may sometimes be referred to as a sound source. The sound source data is digital data sampled at a prescribed sampling period. The sound source data has data that reaches a prescribed reproduction time when the sound source is reproduced at a reproduction speed of 1 time. The first frequency band is, for example, 650 Hz to 950 Hz, and its center frequency is 800 Hz. The first frequency band is not limited to 650 Hz to 950 Hz and may be other frequency bands. The entire first frequency band may be covered in the sound source and the frequency components may be uniformly contained. The sound pressure (amplitude) of each frequency component included in the sound source may also be equal to each other.

[0031] The active sound effect generating device 10 generates a linked sound signal, which is an electrical signal for causing the speaker 12 to output a linked sound that varies in association with the change in the rotational speed of the motor. In addition, the active sound effect generating device 10 generates a background sound signal, which is an electrical signal for causing the speaker 12 to output a background sound that does not vary in association with the change in the rotational speed of the motor. Figure 2 It is a schematic diagram showing the frequency band of the linked sound and the frequency band of the background sound.

[0032] The first linked sound signal generation unit 18 generates a first linked sound signal Sa1. The first linked sound signal Sa1 is a signal of a sound composed of a plurality of frequency components in a specified frequency band centered on the 24th-order frequency of the rotational speed of the motor. The specified frequency band centered on the 24th-order frequency of the rotational speed of the motor is Figure 2 shown as bandwidth A in

[0033] The second linked sound signal generation unit 20 generates a second linked sound signal Sa2. The second linked sound signal Sa2 is a signal of a sound composed of a plurality of frequency components in a specified frequency band centered on the 48th-order frequency of the rotational speed of the motor. The specified frequency band centered on the 48th-order frequency of the rotational speed of the motor is Figure 2 shown as bandwidth B in

[0034] The first background sound signal generation unit 22 generates a first background sound signal Sb1. The first background sound signal Sb1 is a signal of a sound composed of a plurality of frequency components in a specified frequency band centered on the frequency f1. The specified frequency band centered on the frequency f1 is Figure 2 shown as bandwidth C in. The state of outputting the first background sound signal Sb1 to the output unit 30 and the state of not outputting the first background sound signal Sb1 to the output unit 30 are switched by the first selection switch 23. In the present embodiment, the state of outputting the first background sound signal Sb1 to the output unit 30 is selected by the first selection switch 23.

[0035] The second background sound signal generation unit 24 generates a second background sound signal Sb2. The second background sound signal Sb2 is a signal of a sound composed of a plurality of frequency components in a specified frequency band centered on the frequency f2. The specified frequency band centered on the frequency f2 is Figure 2 shown as bandwidth D in. The state of outputting the second background sound signal Sb2 to the output unit 30 and the state of not outputting the second background sound signal Sb2 to the output unit 30 are switched by the second selection switch 25. In the present embodiment, the state of outputting the second background sound signal Sb2 to the output unit 30 is selected by the second selection switch 25.

[0036] The third background sound signal generation unit 26 generates a third background sound signal Sb3. The third background sound signal Sb3 is a signal of a sound composed of a plurality of frequency components in a specified frequency band centered on a frequency f3. The specified frequency band centered on the frequency f3 is represented as a bandwidth E in Figure 2 The state where the third background sound signal Sb3 is output to the output unit 30 and the state where the third background sound signal Sb3 is not output to the output unit 30 are switched by the third selection switch 27. In the present embodiment, the state where the third background sound signal Sb3 is output to the output unit 30 is selected by the third selection switch 27.

[0037] The fourth background sound signal generation unit 28 generates a fourth background sound signal Sb4. The fourth background sound signal Sb4 is a signal of a sound composed of a plurality of frequency components in a specified frequency band centered on a frequency f4. The specified frequency band centered on the frequency f4 is not shown in Figure 2 The state where the fourth background sound signal Sb4 is output to the output unit 30 and the state where the fourth background sound signal Sb4 is not output to the output unit 30 are switched by the fourth selection switch 29. In the present embodiment, the state where the fourth background sound signal Sb4 is not output to the output unit 30 is selected by the fourth selection switch 29.

[0038] The output unit 30 synthesizes the first linked sound signal Sa1, the second linked sound signal Sa2, the first background sound signal Sb1, the second background sound signal Sb2, the third background sound signal Sb3, and the fourth background sound signal Sb4 to generate a sound effect signal Sc. In the present embodiment, since the fourth background sound signal Sb4 is not output to the output unit 30, actually, the output unit 30 synthesizes the first linked sound signal Sa1, the second linked sound signal Sa2, the first background sound signal Sb1, the second background sound signal Sb2, and the third background sound signal Sb3 to generate the sound effect signal Sc. The output unit 30 outputs the generated sound effect signal Sc to the speaker 12. The speaker 12 generates a sound effect corresponding to the sound effect signal Sc in the vehicle compartment.

[0039] Figure 3 is a graph showing the frequency components of the motor sound and the frequency components of the synthesized sound. The synthesized sound is the synthesized sound of the motor sound and the sound effect signal Sc generated from the speaker 12. Figure 3 The graph shown by the thin line in represents the frequency components of the motor sound, and the graph shown by the thick line represents the frequency components of the synthesized sound. Figure 3 represents the frequency components when the motor is at a rotational speed N1 (refer to Figure 2 ). In addition, the motor sound is not limited to the sound generated by the motor itself. The motor sound may also include the sound generated by a gear rotating synchronously with the motor, etc.

[0040] As Figure 3As shown, the sound pressure levels of the 24th-order frequency components and the 48th-order frequency components are more prominent than those of other frequency components. Therefore, the sounds of the 24th-order frequency components and the 48th-order frequency components are clearly heard by the vehicle occupants, which may cause discomfort to the occupants. Therefore, by causing the speaker 12 to generate the first linked sound signal Sa1, the sound pressure level of the components in the frequency band within a specified range centered on the 24th-order frequency is increased (refer to the part shown as A in Figure 3 . In addition, by generating the second linked sound signal Sa2, the sound pressure level of the components in the frequency band within a specified range centered on the 48th-order frequency is increased (refer to the part shown as B in Figure 3 . Accordingly, it is possible to obtain a synthesized sound in which the prominence of the sounds of the 24th-order frequency components and the 48th-order frequency components is alleviated and which is linked to the change in the rotational speed of the motor.

[0041] The order of the frequency components with prominent sound pressure levels varies depending on the specifications of the motor, the transmission, the power transmission system, etc. Therefore, the order of the frequency components with prominent sound pressure levels is not limited to the 24th order and the 48th order. In addition, the number of parts with prominent sound pressure levels varies depending on the specifications of the motor, the transmission, the power transmission system, etc. Therefore, the number of parts with prominent sound pressure levels is not limited to two parts (the 24th order and the 48th order). For example, when the sound pressure level is prominent at three parts, in addition to the first linked sound signal generation unit 18 and the second linked sound signal generation unit 20 shown in Figure 1 , a third linked sound signal generation unit (not shown) may also be provided in the active sound effect generation device 10.

[0042] In addition, sometimes the vehicle body resonates with the motor sound, and the sound pressure level of the components of the resonance frequency of the vehicle body is more prominent than that of other frequency components. Therefore, by causing the speaker 12 to generate the first background sound signal Sb1, the second background sound signal Sb2, and the third background sound signal Sb3, it is possible to increase the sound pressure level of the components in the frequency band within a specified range centered on the resonance frequency of the vehicle body (refer to the parts shown as C, D, and E in Figure 2 . Accordingly, it is possible to obtain a synthesized sound in which the prominence of the resonance sound is alleviated.

[0043] The resonance frequency varies depending on the vehicle body. Therefore, the center frequencies of the first background sound signal Sb1, the second background sound signal Sb2, and the third background sound signal Sb3 are adjusted and determined according to the vehicle body. In addition, the number of resonance frequencies also varies depending on the vehicle body. Therefore, the background sound is not limited to the three types of the first background sound signal Sb1, the second background sound signal Sb2, and the third background sound signal Sb3, and may also be two or less types of background sounds or four or more types of background sounds. For example, when the number of types of background sounds is two, it can be achieved byFigure 1 The third selection switch 27 shown is used to select a state in which the third background sound signal Sb3 is not output to the output unit 30. For example, when there are four types of background sounds, the Figure 1 The fourth selection switch 29 shown is used to select a state in which the fourth background sound signal Sb4 is output to the output unit 30. For example, when there are five types of background sounds, in addition to Figure 1 the first background sound signal generation unit 22, the second background sound signal generation unit 24, the third background sound signal generation unit 26, and the fourth background sound signal generation unit 28 shown, a fifth background sound signal generation unit (not shown) may also be provided in the active sound effect generation device 10.

[0044] [Structure of the linked sound signal generation unit] Figure 4 It is a block diagram showing the structure of the first linked sound signal generation unit 18 in the present embodiment. The first linked sound signal generation unit 18 includes a playback magnification setting unit 32, a signal generation unit 34, a gain setting unit 35, and a correction unit 46.

[0045] The playback magnification setting unit 32 sets the playback magnification α of the sound source data. The playback magnification α is obtained by the following formula (1) according to the rotational speed N [rpm] of the motor. Fa in formula (1) is the center frequency [Hz] of the first frequency band of the aforementioned sound source.

[0046]

[0047] The signal generation unit 34 generates a first linked sound signal sa1 based on the sound source data. The first linked sound signal sa1 is a signal before the amplitude is corrected. In the correction unit 46 described later, the amplitude of the first linked sound signal sa1 is corrected to generate a first linked sound signal Sa1. The sound source data is a signal of a sound source composed of a plurality of frequency components in the first frequency band with a center frequency of fa [Hz]. The first linked sound signal sa1 is a signal of a first linked sound composed of a plurality of frequency components in the second frequency band with the 24th-order frequency of the rotational speed of the motor as the center frequency. The first linked sound is generated by playing back the sound source at α times speed. Therefore, the signal generation unit 34 selects digital signals every (α - 1) from the digital signal string of the sound source data, and arranges the selected digital signals in time sequence, thereby generating a digital signal string of the first linked sound signal sa1. By repeatedly arranging the selected digital signals, a first linked sound signal sa1 with a playback time longer than the playback time of the original sound source data can be generated.

[0048] The gain setting unit 35 functions as a first gain setting unit 36, a second gain setting unit 38, a third gain setting unit 40, a fourth gain setting unit 42, and a fifth gain setting unit 44.

[0049] The first gain setting unit 36 sets the gain G1 according to the output of the motor. Figure 5 is a mapping diagram of the gain G1 in the present embodiment. The second gain setting unit 38 sets the gain G2 according to the acceleration and deceleration of the vehicle. Figure 6 is a mapping diagram of the gain G2 in the present embodiment. The third gain setting unit 40 sets the gain G3 according to the remaining battery charge. Figure 7 is a mapping diagram of the gain G3 in the present embodiment. The battery is charged by the regenerative power during motor regeneration. The fourth gain setting unit 42 sets the gain G4 according to the accelerator pedal opening. Figure 8 is a mapping diagram of the gain G4 in the present embodiment. The fifth gain setting unit 44 sets the gain G5 according to the slope of the road surface on which the vehicle is traveling. Figure 9 is a mapping diagram of the gain G5 in the present embodiment.

[0050] The correction unit 46 multiplies the first linked sound signal sa1 generated in the signal generation unit 34 by the gains G1 to G5 to generate the first linked sound signal Sa1. The first linked sound signal sa1 generated in the signal generation unit 34 corresponds to the first sound effect signal of the present invention. The first linked sound signal Sa1 generated in the correction unit 46 corresponds to the second sound effect signal of the present invention.

[0051] Similar to the first linked sound signal generation unit 18, the second linked sound signal generation unit 20 has a playback magnification setting unit 32, a signal generation unit 34, a gain setting unit 35, and a correction unit 46. The difference between the second linked sound signal generation unit 20 and the first linked sound signal generation unit 18 is that the playback magnification α is obtained by the following formula (2) in the playback magnification setting unit 32, but other structures are the same as those of the first linked sound signal generation unit 18.

[0052]

[0053] [Structure of background sound signal generation unit] Figure 10 is a block diagram showing the structure of the first background sound signal generation unit 22 in the present embodiment. The first background sound signal generation unit 22 has a playback magnification setting unit 48, a signal generation unit 50, a gain setting unit 51, and a correction unit 62.

[0054] The playback magnification setting unit 48 sets the playback magnification β of the sound source data. The playback magnification β is obtained by the following formula (3) according to the center frequency f1 [Hz] of the first background sound signal Sb1.

[0055]

[0056] The signal generation unit 50 generates a first background sound signal sb1 based on the sound source data. The first background sound signal sb1 is the signal before the amplitude is corrected. In the correction unit 62 described later, the amplitude of the first background sound signal sb1 is corrected to generate a first background sound signal Sb1. The sound source data is the signal of a sound source composed of a plurality of frequency components in a first frequency band with a center frequency of fa [Hz]. The first background sound signal sb1 is the signal of a first background sound composed of a plurality of frequency components in a third frequency band with a center frequency of f1 [Hz]. The first background sound is generated by playing back the sound source at β times speed. Therefore, the signal generation unit 50 generates a digital signal string of the first background sound signal sb1 by selecting every (β - 1)th digital signal from the digital signal string of the sound source data and arranging the selected digital signals in time sequence. By repeatedly arranging the selected digital signals, a first background sound signal sb1 with a playback time longer than the playback time of the original sound source data can be generated.

[0057] The gain setting unit 51 functions as a first gain setting unit 52, a second gain setting unit 54, a third gain setting unit 56, a fourth gain setting unit 58, and a fifth gain setting unit 60.

[0058] The first gain setting unit 52 sets a gain G1 according to the output of the motor. The gain G1 is set according to the mapping diagram of the aforementioned Figure 5 . The second gain setting unit 54 sets a gain G2 according to the acceleration and deceleration of the vehicle. The gain G2 is set according to the mapping diagram of the aforementioned Figure 6 . The third gain setting unit 56 sets a gain G3 according to the remaining battery charge. The gain G3 is set according to the mapping diagram of the aforementioned Figure 7 . The fourth gain setting unit 58 sets a gain G4 according to the accelerator pedal opening. The gain G4 is set according to the mapping diagram of the aforementioned Figure 8 . The fifth gain setting unit 60 sets a gain G5 according to the slope of the road surface on which the vehicle is traveling. The gain G5 is set according to the mapping diagram of the aforementioned Figure 9 .

[0059] The correction unit 62 generates a first background sound signal Sb1 by multiplying the first background sound signal sb1 generated in the signal generation unit 50 by gains G1 to G5. The first background sound signal sb1 generated in the signal generation unit 50 corresponds to the first sound effect signal of the present invention. The first background sound signal Sb1 generated in the correction unit 62 corresponds to the second sound effect signal of the present invention.

[0060] Similar to the first background sound signal generation unit 22, the second background sound signal generation unit 24 includes a playback magnification setting unit 48, a signal generation unit 50, a gain setting unit 51, and a correction unit 62. The difference between the second background sound signal generation unit 24 and the first background sound signal generation unit 22 is that the playback magnification β is obtained by the following formula (4) in the playback magnification setting unit 48, but the other structures are the same as those of the first background sound signal generation unit 22.

[0061]

[0062] Similar to the first background sound signal generation unit 22, the third background sound signal generation unit 26 includes a playback magnification setting unit 48, a signal generation unit 50, a gain setting unit 51, and a correction unit 62. The difference between the third background sound signal generation unit 26 and the first background sound signal generation unit 22 is that the playback magnification β is obtained by the following formula (5) in the playback magnification setting unit 48, but the other structures are the same as those of the first background sound signal generation unit 22.

[0063]

[0064] Similar to the first background sound signal generation unit 22, the fourth background sound signal generation unit 28 includes a playback magnification setting unit 48, a signal generation unit 50, a gain setting unit 51, and a correction unit 62. The difference between the fourth background sound signal generation unit 28 and the first background sound signal generation unit 22 is that the playback magnification β is obtained by the following formula (6) in the playback magnification setting unit 48, but the other structures are the same as those of the first background sound signal generation unit 22.

[0065]

[0066] [Regarding Gain] As described above, the first gain setting unit 36 sets the gain G1 based on Figure 5 the mapping diagram according to the output of the motor.

[0067] As Figure 5 shown, when the output of the motor is above the specified output Wa [kW] (Wa < 0) and less than the specified output Wb [kW] (Wb > 0), the gain G1 is set to a value below the specified gain Ga. When the sound effect signal Sc is below the specified gain Ga, the sound effect output from the speaker 12 will be drowned out by the outside noise of the vehicle and the driving sound of the vehicle, and the passengers in the compartment can hardly recognize it. Accordingly, when the vehicle speed is extremely low, the passengers cannot recognize the sound effect, which can improve the quietness inside the compartment.

[0068] As Figure 5As shown, when the output of the motor is equal to or greater than the specified output Wc [kW] (Wc > Wb), it is set such that the greater the output of the motor, the greater the gain G1. Accordingly, the sound pressure of the sound effect increases proportionally according to the acceleration of the vehicle, enabling the occupant to perceive the linear relationship between the vehicle behavior and the sound effect.

[0069] As Figure 5 shown, when the output of the motor is equal to or greater than the specified output Wd [kW] (Wd < Wa) and less than the specified output Wa [kW], it is set such that the greater the amount of regeneration of the motor, the greater the gain G1. Accordingly, the sound pressure of the sound effect increases proportionally according to the deceleration of the vehicle, enabling the occupant to perceive the linear relationship between the vehicle behavior and the sound effect.

[0070] As Figure 5 shown, when the output of the motor is less than the specified output Wd [kW], regardless of the amount of regeneration of the motor, the magnitude of the gain G1 is made constant. Accordingly, the sound pressure of the sound effect when the vehicle decelerates does not become too large, and the discomfort of the occupant can be suppressed.

[0071] As described above, the second gain setting unit 38 sets the gain G2 based on Figure 6 the mapping diagram according to the acceleration and deceleration of the vehicle.

[0072] As Figure 6 shown, when the acceleration and deceleration of the vehicle are equal to or greater than the specified acceleration and deceleration Aa [G] (Aa < 0) and less than the specified acceleration and deceleration Ab [G] (Ab > 0), it is set such that the farther the acceleration and deceleration of the vehicle are from 0 [G], the greater the gain G2. Accordingly, when the vehicle is in the cruise driving state, the sound effect can be reduced and the quietness inside the vehicle can be improved. In addition, when the vehicle behavior changes from the cruise driving state to the acceleration and deceleration state, the sound pressure of the sound effect can be smoothly changed, giving the occupant a sense of unity between the vehicle behavior and the sound effect.

[0073] In addition, when the acceleration and deceleration of the vehicle are less than the specified acceleration and deceleration Aa [G] or when the acceleration and deceleration of the vehicle are equal to or greater than the specified acceleration and deceleration Ab [G], regardless of the acceleration and deceleration of the vehicle, the magnitude of the gain G2 is made constant. When the acceleration and deceleration of the vehicle are less than the specified acceleration and deceleration Aa [G] or when the acceleration and deceleration of the vehicle are equal to or greater than Ab [G], regardless of the acceleration and deceleration, the sound pressure of the sound effect changes according to the output of the motor.

[0074] As described above, the third gain setting unit 40 sets the gain G3 based on Figure 7 the mapping diagram according to the remaining battery charge.

[0075] As Figure 7As shown, when the remaining battery power is equal to or greater than the specified amount Qa [%], the gain G3 is smaller than when the remaining battery power is less than the specified amount Qa [%]. Accordingly, when the battery is nearly fully charged, the sound pressure of the sound effect becomes smaller. Accordingly, when the vehicle is decelerating, it is possible to create a difference in the sound pressure of the sound effect during the positive regeneration of the motor and the sound pressure of the sound effect when the motor is not regenerating. Therefore, it is possible to make the occupant aware that the motor is not regenerating. When the vehicle is accelerating, the remaining battery power decreases. Therefore, there is no difference in the sound pressure of the sound effect during the positive power operation of the motor and the sound pressure of the sound effect when the motor is not in power operation.

[0076] In addition, as Figure 7 shown, when the remaining battery power is less than the specified amount Qb [%], the gain G3 is smaller than when the remaining battery power is equal to or greater than the specified amount Qb [%]. Accordingly, when the battery has little remaining power, the sound pressure of the sound effect becomes smaller. Therefore, it is possible to make the occupant aware that the battery has little remaining power.

[0077] As described above, the fourth gain setting unit 42 sets the gain G4 based on the Figure 8 mapping diagram according to the accelerator pedal opening.

[0078] As Figure 8 shown, when the accelerator pedal opening is less than the specified opening Pa [%], it is set that the larger the accelerator pedal opening, the larger the gain G4. Accordingly, the sound pressure of the sound effect increases proportionally according to the accelerator pedal opening, and it is possible to make the occupant feel the linear relationship between the accelerator pedal operation and the sound effect.

[0079] As Figure 8 shown, when the accelerator pedal opening is equal to or greater than the specified opening Pa [%], regardless of the size of the accelerator pedal opening, the size of the gain G4 is made constant. Accordingly, when the occupant steps on the accelerator pedal, the sound pressure of the sound effect does not become too large, and it is possible to suppress the discomfort of the occupant.

[0080] As described above, the fifth gain setting unit 44 sets the gain G5 based on the Figure 9 mapping diagram according to the slope of the road surface on which the vehicle is traveling.

[0081] When the upward slope of the road surface is large, the accelerator pedal opening becomes larger. The larger the accelerator pedal opening, the greater the sound pressure of the sound effect. Therefore, during uphill driving of the vehicle, the sound pressure of the sound effect becomes too large, causing discomfort to the occupant. In the present embodiment, as Figure 9 shown, it is set that the larger the upward slope of the road surface, the smaller the gain G5. Therefore, even during uphill driving of the vehicle, it is possible to suppress the sound effect from becoming too large and reduce the discomfort caused to the occupant.

[0082] When the downward slope of the road surface is relatively large, the opening degree of the accelerator pedal becomes smaller. The smaller the opening degree of the accelerator pedal, the smaller the sound pressure of the sound effect. Therefore, during downhill driving of the vehicle, the sound pressure of the sound effect becomes too small. Although regenerative braking occurs during downhill driving of the vehicle, due to the too small sound pressure of the sound effect, discomfort is brought to the occupants. In the present embodiment, as Figure 9 shown, it is set that the greater the downward slope of the road surface, the greater the gain G5. Therefore, even during downhill driving of the vehicle, it is possible to suppress the sound effect from being too small and reduce the discomfort brought to the occupants.

[0083] [Sound effect generation process] Figure 11 is a flowchart of the sound effect generation process executed in the active sound effect generation device 10 in the present embodiment. The electric vehicle repeatedly executes the sound effect generation process at a specified cycle during driving.

[0084] In step S1, the first linked sound signal generation unit 18 generates the first linked sound signal Sa1. In addition, the second linked sound signal generation unit 20 generates the second linked sound signal Sa2. After that, it proceeds to step S2.

[0085] In step S2, the first background sound signal generation unit 22 generates the first background sound signal Sb1. In addition, the second background sound signal generation unit 24 generates the second background sound signal Sb2. In addition, the third background sound signal generation unit 26 generates the third background sound signal Sb3. In addition, the fourth background sound signal generation unit 28 generates the fourth background sound signal Sb4. After that, it proceeds to step S3.

[0086] In step S3, the output unit 30 generates the sound effect signal Sc. In addition, the output unit 30 outputs the sound effect signal Sc to the speaker 12. In this way, the sound effect generation process is performed.

[0087] [Other embodiments] In one embodiment, in the first linked sound signal generation unit 18 and the second linked sound signal generation unit 20 respectively, the correction unit 46 multiplies the first linked sound signal sa1 and the second linked sound signal sa2 generated by the signal generation unit 34 by the gains G1 to G5 to generate the first linked sound signal Sa1 and the second linked sound signal Sa2. In contrast, the gain setting unit 35 may also set the value obtained by multiplying by the gains G1 to G5 as the gain G. In addition, the correction unit 46 may also generate the first linked sound signal Sa1 and the second linked sound signal Sa2 by multiplying the first linked sound signal sa1 and the second linked sound signal sa2 by the gain G.

[0088] In one embodiment, in the first background sound signal generation unit 22, the second background sound signal generation unit 24, the third background sound signal generation unit 26, and the fourth background sound signal generation unit 28 respectively, the correction unit 62 multiplies the first background sound signal sb1, the second background sound signal sb2, the third background sound signal sb3, and the fourth background sound signal sb4 generated by the signal generation unit 50 by gains G1 to G5 to generate the first background sound signal Sb1, the second background sound signal Sb2, the third background sound signal Sb3, and the fourth background sound signal Sb4. In contrast, the gain setting unit 51 may also set the values obtained by multiplying by gains G1 to G5 as the gain G. Additionally, the correction unit 62 may multiply the first background sound signal sb1, the second background sound signal sb2, the third background sound signal sb3, and the fourth background sound signal sb4 by the gain G to generate the first background sound signal Sb1, the second background sound signal Sb2, the third background sound signal Sb3, and the fourth background sound signal Sb4.

[0089] When driving at the same speed as on flat ground during an uphill on the road surface, the output of the motor during uphill driving is greater than the output of the motor during flat ground driving. When setting the gain G only based on the output of the motor, the greater the upward slope of the road surface, the greater the gain G. Therefore, during uphill driving of the vehicle, the sound pressure of the sound effect is too large, causing discomfort to the occupants.

[0090] The gain G is set based on at least the output of the motor, the acceleration of the vehicle, and the slope of the road surface on which the vehicle is traveling. As Figure 5 shown, when the output of the motor is 0 [kW] or more, the greater the output of the motor, the greater the gain G1. As Figure 6 shown, when the acceleration of the vehicle is less than the specified acceleration Ab [G], the smaller the acceleration, the smaller the gain G2. Additionally, as Figure 9 shown, the greater the upward slope of the road surface, the smaller the gain G5.

[0091] Accordingly, when the vehicle is cruising uphill at a constant speed, it is possible to suppress the sound effect from becoming too large and reduce the discomfort caused to the occupants.

[0092] Regarding the above embodiment, the following remarks are also disclosed.

[0093] (Remark 1) The active sound generation device (10) of the present invention outputs sound into the passenger compartment of a vehicle driven by an electric motor through a speaker (12). The active sound generation device (10) includes a signal generation unit (34), a gain setting unit (35), and an output unit (30). Among them, the signal generation unit (34) generates a signal, namely a first sound signal, for causing the speaker to output the sound; the gain setting unit (35) sets a gain according to the regeneration amount of the electric motor; the output unit (30) outputs a second sound signal generated by multiplying the first sound signal by the gain to the speaker. Accordingly, the sound effect can be changed according to the regeneration amount of the electric motor.

[0094] (Addendum 2) In the active sound generation device described in Addendum 1, it may also be that the gain when the remaining power of the vehicle's battery is above a specified amount is smaller than the gain when the remaining power of the battery is less than the specified amount, where the vehicle's battery is charged by the regenerative power of the electric motor. Accordingly, the sound effect when the electric motor is in positive regeneration can be made different from the sound effect when the electric motor is not in positive regeneration.

[0095] (Addendum 3) In the active sound generation device described in Addendum 1, it may also be that the gain setting unit further sets the gain according to the slope of the road surface on which the vehicle is traveling. Accordingly, the sound effect can be changed according to the slope of the road surface on which the vehicle is traveling.

[0096] (Addendum 4) In the active sound generation device described in Addendum 1, it may also be that the greater the regeneration amount, the greater the gain. Accordingly, the sound effect can be changed according to the regeneration amount of the electric motor.

[0097] (Addendum 5) In the active sound generation device described in Addendum 1, it may also be that the gain setting unit further sets the gain according to the deceleration of the vehicle, and the greater the deceleration, the greater the gain. Accordingly, the sound effect can be changed according to the deceleration of the vehicle.

[0098] (Addendum 6) In the active sound generation device described in Addendum 3, it may also be that the greater the upward slope of the road surface, the smaller the gain, and the greater the downward slope of the road surface, the greater the gain. Accordingly, it is possible to prevent the sound pressure of the sound effect from becoming too large during uphill driving of the vehicle. In addition, it is possible to prevent the sound pressure of the sound effect from becoming too small during downhill driving of the vehicle.

[0099] (Addendum 7) In the active sound effect generation device described in Supplementary Note 1, it may also be that the gain setting unit sets the gain based on the output of the motor, the slope of the road surface on which the vehicle is traveling, and the acceleration of the vehicle. Accordingly, the sound pressure of the sound effect is adjusted according to the output of the motor, the slope of the road surface, and the acceleration of the vehicle.

[0100] (Supplementary Note 8) In the active sound effect generation device described in Supplementary Note 7, it may also be that the greater the output of the motor, the greater the gain, the greater the upward slope of the road surface, the smaller the gain, and the smaller the acceleration, the smaller the gain. Accordingly, it is possible to prevent the sound pressure of the sound effect from becoming too large when the vehicle is traveling uphill.

[0101] (Supplementary Note 9) The active sound effect generation method of the present invention outputs a sound effect from a speaker into the passenger compartment of a vehicle driven by a motor. The active sound effect generation method generates a first sound effect signal, which is a signal for causing the speaker to output the sound effect, sets a gain according to the regeneration amount of the motor, and outputs a second sound effect signal generated by multiplying the first sound effect signal by the gain to the speaker. Accordingly, the sound effect can be changed according to the regeneration amount of the motor.

[0102] The present invention has been described in detail, but the present invention is not limited to the above-described embodiments. These embodiments can be variously added, replaced, changed, partially deleted, etc. within the scope of not departing from the gist of the present invention or within the scope of not departing from the gist of the present invention derived from the content described in the technical solution and its equivalents. In addition, these embodiments can also be implemented in combination. For example, in the above-described embodiments, the order of each operation and the order of each process are shown as an example, but are not limited thereto. The same applies when numerical values or mathematical formulas are used in the description of the above-described embodiments.

Claims

1. An active sound effect generating device (10) that outputs a sound effect into the passenger compartment of a vehicle driven by an electric motor by a speaker (12), characterized in that it has a signal generation unit (34), a gain setting unit (35), and an output unit (30), where the signal generation unit (34) generates a signal for causing the speaker to output the sound effect, that is, a first sound effect signal; the gain setting unit (35) sets a gain according to the regeneration amount of the electric motor; the output unit (30) outputs a second sound effect signal generated by multiplying the first sound effect signal by the gain to the speaker.

2. The active sound effect generating device according to claim 1, characterized in that the gain when the remaining power of the vehicle's battery is above a specified amount is smaller than the gain when the remaining power of the battery is less than the specified amount, where the vehicle's battery is charged by the regenerative power of the electric motor.

3. The active sound effect generating device according to claim 1, characterized in that the gain setting unit also sets the gain according to the slope of the road surface on which the vehicle is traveling.

4. The active sound effect generating device according to claim 1, characterized in that the greater the regeneration amount, the greater the gain.

5. The active sound effect generating device according to claim 1, characterized in that the gain setting unit also sets the gain according to the deceleration of the vehicle, and the greater the deceleration, the greater the gain.

6. The active sound effect generating device according to claim 3, characterized in that the greater the upward slope of the road surface, the smaller the gain, and the greater the downward slope of the road surface, the greater the gain.

7. The active sound effect generating device according to claim 1, characterized in that the gain setting unit sets the gain according to the output of the electric motor, the slope of the road surface on which the vehicle is traveling, and the acceleration of the vehicle.

8. The active sound effect generating device according to claim 7, characterized in that the greater the output of the electric motor, the greater the gain, the greater the upward slope of the road surface, the smaller the gain, and the smaller the acceleration, the smaller the gain.

9. An active sound effect generating method that outputs a sound effect into the passenger compartment of a vehicle driven by an electric motor by a speaker, characterized in that generating a signal for causing the speaker to output the sound effect, that is, a first sound effect signal, setting a gain according to the regeneration amount of the electric motor, outputting a second sound effect signal generated by multiplying the first sound effect signal by the gain to the speaker.

Images