Active type effect sound generation device and active type effect sound generation method

Abstract

To provide an improved active type effect sound generation device and an improved active type effect sound generation method.SOLUTION: An active type effect sound generation device 10 outputting effect sound from a speaker 12 to a cabin of a vehicle driven by an electric motor comprises: a signal generating part which generates a first effect sound signal to cause the speaker to output effect sound; a second gain setting part which sets a gain according to a regeneration amount of the electric motor; and an output part 30 which generates a second effect sound signal by multiplying the first effect sound signal by the gain and outputs the second effect sound signal to the speaker.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to an active sound effect generating device and an active sound effect generating method.

Background Art

[0002] Patent Document 1 below discloses an active sound effect generating device that generates a sound effect from a speaker in the passenger compartment of a vehicle equipped with an electric motor.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] There is a long-felt need for a better active sound effect generating device and an active sound effect generating method.

[0005] An object of the present invention is to solve the above-described problems.

Means for Solving the Problems

[0006] A first aspect of the present disclosure is an active sound effect generating device that outputs a sound effect from a speaker toward the passenger compartment of a vehicle driven by an electric motor, the device including: a signal generation unit that generates a first sound effect signal, which is a signal for outputting the sound effect from the speaker; a gain setting unit that sets a gain according to a regeneration amount of the electric motor; and an output unit that outputs a second sound effect signal, which is generated by multiplying the gain by the first sound effect signal, to the speaker.

[0007] A second aspect of the present disclosure is an active sound effect generation method for outputting a sound effect to a speaker toward the interior of a vehicle driven by an electric motor, the method including generating a first sound effect signal that is a signal for outputting the sound effect to the speaker, setting a gain according to a regeneration amount of the electric motor, and outputting a second sound effect signal generated by multiplying the gain by the first sound effect signal to the speaker.

Advantages of the Invention

[0008] According to the present invention, a better active sound effect generation device and an active sound effect generation method can be provided.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

DETAILED DESCRIPTION OF THE INVENTION

[0010] In a vehicle having an engine as a drive source, when the vehicle is traveling on a downhill road surface, engine braking may be applied. When engine braking is applied, the engine speed increases and the engine noise that sounds in the vehicle interior becomes louder.

[0011] In a vehicle having an electric motor as a drive source, a regenerative brake of the electric motor is used instead of engine braking. When the regenerative brake is applied, since a sound as loud as the engine noise does not sound in the vehicle interior, it is difficult for the passenger to recognize that the regenerative brake is applied.

[0012] In the active effect sound generation device of the present disclosure, it is possible to make the passenger recognize that the regenerative brake is applied.

[0013] 〔Embodiment〕 [Configuration of Active Effect Sound Generation Device] FIG. 1 is a block diagram showing the configuration of an active effect sound generation device 10 according to an embodiment. The active effect sound generation device 10 is mounted on a vehicle driven by an electric motor. A vehicle driven by an electric motor is a BEV (Battery Electric Vehicle), HEV (Hybrid Electric Vehicle), PHEV (plug-in Hybrid Electric Vehicle), FCEV (Fuel Cell Electric Vehicle), or the like. Hereinafter, a vehicle driven by an electric motor will be referred to as an electric vehicle.

[0014] The active effect sound generation device 10 is a device that causes a speaker 12 provided in the vehicle interior of an electric vehicle to output an effect sound that changes according to the rotational speed of the electric motor. The effect sound enhances the attractiveness of the electric vehicle to the passenger.

[0015] The active sound effect generation device 10 includes an arithmetic unit 14 and a storage unit 16. The arithmetic unit 14 is a processor such as a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit).

[0016] 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 realized by a program stored in the storage unit 16 being executed in the arithmetic unit 14.

[0017] At least a part of 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 may be realized 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 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 may be realized by an electronic circuit including discrete devices.

[0018] 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, etc. are stored in the non-volatile memory, for example.

[0019] At least a part of the storage unit 16 may be provided in the above-described processor, integrated circuit, etc. At least a part of the storage unit 16 may be mounted on a device connected to the active sound effect generator 10 via a network.

[0020] 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, a sound composed of a plurality of frequency components in the first frequency band may be referred to as a sound source. The sound source data is digital data sampled at a predetermined sampling period. The sound source data has data that results in a predetermined 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 sound source may contain frequency components evenly over the entire first frequency band. The sound pressure (amplitude) of each frequency component included in the sound source may be equal to each other.

[0021] The active sound effect generator 10 generates a linked sound signal, which is an electrical signal for causing the speaker 12 to output a linked sound that changes in conjunction with fluctuations in the rotational speed of the electric motor. Further, the active sound effect generator 10 generates a background sound signal, which is an electrical signal for causing the speaker 12 to output a background sound that does not change in conjunction with fluctuations in the rotational speed of the electric motor. FIG. 2 is an image diagram showing the frequency band of the linked sound and the frequency band of the background sound.

[0022] The first linked sound signal generation unit 18 generates a first linked sound signal Sa1. The first linked sound signal Sa1 is a sound signal composed of a plurality of frequency components in a frequency band within a predetermined range centered on the 24th frequency of the rotational speed of the electric motor. The frequency band within a predetermined range centered on the 24th frequency of the rotational speed of the electric motor is shown as band A in FIG. 2.

[0023] The second interlocking sound signal generation unit 20 generates a second interlocking sound signal Sa2. The second interlocking sound signal Sa2 is a sound signal composed of a plurality of frequency components in a frequency band within a predetermined range centered on the 48th frequency of the rotational speed of the electric motor. The frequency band within a predetermined range centered on the 48th frequency of the rotational speed of the electric motor is shown as band B in FIG. 2.

[0024] The first background sound signal generation unit 22 generates a first background sound signal Sb1. The first background sound signal Sb1 is a sound signal composed of a plurality of frequency components in a frequency band within a predetermined range centered on the frequency f1. The frequency band within a predetermined range centered on the frequency f1 is shown as band C in FIG. 2. By the first selection switch 23, the state in which the first background sound signal Sb1 is output to the output unit 30 and the state in which the first background sound signal Sb1 is not output to the output unit 30 are switched. In the present embodiment, the state in which the first background sound signal Sb1 is output to the output unit 30 is selected by the first selection switch 23.

[0025] The second background sound signal generation unit 24 generates a second background sound signal Sb2. The second background sound signal Sb2 is a sound signal composed of a plurality of frequency components in a frequency band within a predetermined range centered on the frequency f2. The frequency band within a predetermined range centered on the frequency f2 is shown as band D in FIG. 2. By the second selection switch 25, the state in which the second background sound signal Sb2 is output to the output unit 30 and the state in which the second background sound signal Sb2 is not output to the output unit 30 are switched. In the present embodiment, the state in which the second background sound signal Sb2 is output to the output unit 30 is selected by the second selection switch 25.

[0026] The third background sound signal generation unit 26 generates a third background sound signal Sb3. The third background sound signal Sb3 is a sound signal composed of a plurality of frequency components in a frequency band within a predetermined range centered on the frequency f3. The frequency band within a predetermined range centered on the frequency f3 is shown as the band E in FIG. 2. The third selection switch 27 switches between a state in which the third background sound signal Sb3 is output to the output unit 30 and a state in which the third background sound signal Sb3 is not output to the output unit 30. In the present embodiment, the third selection switch 27 selects a state in which the third background sound signal Sb3 is output to the output unit 30.

[0027] The fourth background sound signal generation unit 28 generates a fourth background sound signal Sb4. The fourth background sound signal Sb4 is a sound signal composed of a plurality of frequency components in a frequency band within a predetermined range centered on the frequency f4. The frequency band within a predetermined range centered on the frequency f4 is not shown in FIG. 2. The fourth selection switch 29 switches between a state in which the fourth background sound signal Sb4 is output to the output unit 30 and a state in which the fourth background sound signal Sb4 is not output to the output unit 30. In the present embodiment, the fourth selection switch 29 selects a state in which the fourth background sound signal Sb4 is not output to the output unit 30.

[0028] The output unit 30 synthesizes the first interlocking sound signal Sa1, the second interlocking 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 an effect sound 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 interlocking sound signal Sa1, the second interlocking 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 effect sound signal Sc. The output unit 30 outputs the generated effect sound signal Sc to the speaker 12. The speaker 12 generates an effect sound corresponding to the effect sound signal Sc in the vehicle interior.

[0029] FIG. 3 is a graph showing the frequency components of the electric motor sound and the frequency components of the synthesized sound. The synthesized sound is a synthesized sound of the electric motor sound and the effect sound signal Sc generated from the speaker 12. The graph shown by the thin line in FIG. 3 shows the frequency components of the electric motor sound, and the graph shown by the thick line shows the frequency components of the synthesized sound. FIG. 3 shows the frequency components when the electric motor is at the rotational speed N1 (see FIG. 2). Note that the electric motor sound is not limited to the sound generated by the electric motor itself. The electric motor sound may include the sound generated by a gear that rotates in synchronization with the electric motor and the like.

[0030] As shown in FIG. 3, the sound pressure levels of the 24th-order frequency component and the 48th-order frequency component are prominent compared to the sound pressure levels of other frequency components. Therefore, to the vehicle occupants, the sound of the 24th-order frequency component and the sound of the 48th-order frequency component are likely to be prominently heard, which may give the occupants a sense of discomfort. Therefore, by generating the first interlocking sound signal Sa1 from the speaker 12, the sound pressure level of the components in a predetermined frequency band centered on the 24th-order frequency is increased (see the portion indicated by A in FIG. 3). Also, by generating the second interlocking sound signal Sa2, the sound pressure level of the components in a predetermined frequency band centered on the 48th-order frequency is increased (see the portion indicated by B in FIG. 3). Thereby, it is possible to obtain a synthesized sound that is linked to the fluctuation of the rotational speed of the electric motor, in which the prominence of the sound of the 24th-order frequency component and the sound of the 48th-order frequency component is alleviated.

[0031] The order of the frequency component with a prominent sound pressure level varies according to the specifications of the electric motor, the transmission, the power train, and the like. Therefore, the order of the frequency component with a prominent sound pressure level is not limited to the 24th order and the 48th order. Also, the number of locations where the sound pressure level is prominent varies according to the specifications of the electric motor, the transmission, the power train, and the like. Therefore, the locations where the sound pressure level is prominent are not limited to two locations (the 24th order and the 48th order). For example, when the sound pressure level is prominent at three locations, in addition to the first interlocking sound signal generation unit 18 and the second interlocking sound signal generation unit 20 shown in FIG. 1, a third interlocking sound signal generation unit (not shown) may be provided in the active type effect sound generation device 10.

[0032] In addition, the vehicle body may resonate with the electric motor sound, and the sound pressure level of the component at the resonance frequency of the vehicle body may be prominent compared to the sound pressure levels of other frequency components. Therefore, by generating the first background sound signal Sb1, the second background sound signal Sb2, and the third background sound signal Sb3 from the speaker 12, the sound pressure level of the component in the frequency band within a predetermined range centered on the resonance frequency of the vehicle body is increased (see the portions indicated by C, D, and E in FIG. 2). Thereby, a synthesized sound with reduced prominence of the resonance sound can be obtained.

[0033] Since the resonance frequency varies depending on the vehicle body, the center frequencies of the first background sound signal Sb1, the second background sound signal Sb2, and the third background sound signal Sb3 are determined by being adjusted for each vehicle body. Also, since the number of resonance frequencies also varies depending on the vehicle body, 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 be two or fewer types of background sound or four or more types of background sound. For example, when the number of types of background sound is two, the third selection switch 27 shown in FIG. 1 may be used to select a state in which the third background sound signal Sb3 is not output to the output unit 30. For example, when the number of types of background sound is four, the fourth selection switch 29 shown in FIG. 1 may be used to select a state in which the fourth background sound signal Sb4 is output to the output unit 30. For example, when the number of types of background sound is five, in addition to 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 in FIG. 1, a fifth background sound signal generation unit (not shown) may be provided in the active sound effect generation device 10.

[0034] [Configuration of Interlocking Sound Signal Generation Unit] FIG. 4 is a block diagram showing the configuration of the first interlocking sound signal generation unit 18 in the present embodiment. The first interlocking sound signal generation unit 18 includes a reproduction magnification setting unit 32, a signal generation unit 34, a gain setting unit 35, and a correction unit 46.

[0035] 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 electric motor. In formula (1), fa is the center frequency [Hz] of the first frequency band of the aforementioned sound source.

[0036]

Number

[0037] The signal generation unit 34 generates a first linked sound signal sa1 from the sound source data. The first linked sound signal sa1 is the 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 the 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 frequency of the rotational speed of the electric motor as the center frequency. The first linked sound is created 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 sequence of the sound source data and arranges the selected digital signals along the time series to generate the digital signal sequence 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.

[0038] 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.

[0039] The first gain setting unit 36 sets the gain G1 according to the output of the electric motor. FIG. 5 is a map 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. FIG. 6 is a map of the gain G2 in the present embodiment. The third gain setting unit 40 sets the gain G3 according to the remaining amount of the battery. FIG. 7 is a map of the gain G3 in the present embodiment. The battery is charged by the regenerative power during the regeneration of the electric motor. The fourth gain setting unit 42 sets the gain G4 according to the accelerator pedal opening. FIG. 8 is a map of the gain G4 in the present embodiment. The fifth gain setting unit 44 sets the gain G5 according to the gradient of the road surface on which the vehicle is traveling. FIG. 9 is a map of the gain G5 in the present embodiment.

[0040] The correction unit 46 multiplies the first linked sound signal sa1 generated by 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 by the signal generation unit 34 corresponds to the first effect sound signal of the present invention. The first linked sound signal Sa1 generated by the correction unit 46 corresponds to the second effect sound signal of the present invention.

[0041] Similar to the first linked sound signal generation unit 18, the second linked sound signal generation unit 20 includes a playback magnification setting unit 32, a signal generation unit 34, a gain setting unit 35, and a correction unit 46. The second linked sound signal generation unit 20 is different from the first linked sound signal generation unit 18 in that the playback magnification α is obtained by the following formula (2) in the playback magnification setting unit 32, but the other configurations are the same as those of the first linked sound signal generation unit 18.

[0042]

Equation

[0043] [Configuration of Background Sound Signal Generation Unit] FIG. 10 is a block diagram showing the configuration of the first background sound signal generation unit 22 in the present embodiment. The first background sound signal generation unit 22 includes a playback magnification setting unit 48, a signal generation unit 50, a gain setting unit 51, and a correction unit 62.

[0044] The reproduction magnification setting unit 48 sets the reproduction magnification β of the sound source data. The reproduction magnification β is obtained by the following formula (3) according to the center frequency f1 [Hz] of the first background sound signal Sb1.

[0045]

Equation

[0046] The signal generation unit 50 generates a first background sound signal sb1 from the sound source data. The first background sound signal sb1 is a 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 the first background sound signal Sb1. The sound source data is a 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 a signal of a first background sound composed of a plurality of frequency components in a third frequency band with f1 [Hz] as the center frequency. The first background sound is generated by reproducing the sound source at β times the speed. Therefore, the signal generation unit 50 selects digital signals every (β - 1) from the digital signal sequence of the sound source data, and arranges the selected digital signals in time series to generate the digital signal sequence of the first background sound signal sb1. By repeatedly arranging the selected digital signals, a first background sound signal sb1 with a reproduction time longer than the reproduction time of the original sound source data can be generated.

[0047] 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.

[0048] The first gain setting unit 52 sets the gain G1 according to the output of the electric motor. The gain G1 is set based on the map in FIG. 5 described above. The second gain setting unit 54 sets the gain G2 according to the acceleration and deceleration of the vehicle. The gain G2 is set based on the map in FIG. 6 described above. The third gain setting unit 56 sets the gain G3 according to the remaining amount of the battery. The gain G3 is set based on the map in FIG. 7 described above. The fourth gain setting unit 58 sets the gain G4 according to the accelerator pedal opening. The gain G4 is set based on the map in FIG. 8 described above. The fifth gain setting unit 60 sets the gain G5 according to the gradient of the road surface on which the vehicle is traveling. The gain G5 is set based on the map in FIG. 9 described above.

[0049] The correction unit 62 multiplies the first background sound signal sb1 generated by the signal generation unit 50 by the gains G1 to G5 to generate the first background sound signal Sb1. The first background sound signal sb1 generated by the signal generation unit 50 corresponds to the first effect sound signal of the present invention. The first background sound signal Sb1 generated by the correction unit 62 corresponds to the second effect sound signal of the present invention.

[0050] The second background sound signal generation unit 24 has a playback magnification setting unit 48, a signal generation unit 50, a gain setting unit 51, and a correction unit 62, similar to the first background sound signal generation unit 22. The second background sound signal generation unit 24 is different from the first background sound signal generation unit 22 in that the playback magnification β is obtained by the following formula (4) in the playback magnification setting unit 48, but the other configurations are the same as those of the first background sound signal generation unit 22.

[0051]

Equation

[0052] The third background sound signal generation unit 26 has a playback magnification setting unit 48, a signal generation unit 50, a gain setting unit 51, and a correction unit 62, similar to the first background sound signal generation unit 22. The third background sound signal generation unit 26 differs from the first background sound signal generation unit 22 in that the playback magnification β is obtained by the following formula (5) in the playback magnification setting unit 48, but the other configurations are the same as those of the first background sound signal generation unit 22.

[0053]

Number

[0054] The fourth background sound signal generation unit 28 has a playback magnification setting unit 48, a signal generation unit 50, a gain setting unit 51, and a correction unit 62, similar to the first background sound signal generation unit 22. The fourth background sound signal generation unit 28 differs from the first background sound signal generation unit 22 in that the playback magnification β is obtained by the following formula (6) in the playback magnification setting unit 48, but the other configurations are the same as those of the first background sound signal generation unit 22.

[0055]

Number

[0056] [Regarding the gain] As described above, the first gain setting unit 36 sets the gain G1 according to the output of the electric motor based on the map in FIG. 5.

[0057] As shown in FIG. 5, when the output of the electric motor is equal to or greater than a predetermined output Wa [kW] (Wa <0) and less than a predetermined output Wb [kW] (Wb> 0), the gain G1 is set to a value equal to or less than a predetermined gain Ga. When the sound effect signal Sc is equal to or less than the predetermined gain Ga, the sound effect output from the speaker 12 is buried in the outside noise of the vehicle or the running sound of the vehicle, and the passengers in the vehicle interior can hardly recognize it. As a result, when the vehicle speed is extremely low, the passengers cannot recognize the sound effect, and the quietness in the vehicle interior can be improved.

[0058] As shown in FIG. 5, when the output of the electric motor is equal to or greater than a predetermined output Wc [kW] (Wc>Wb), the gain G1 is set to increase as the output of the electric motor increases. Thereby, the sound pressure of the effect sound increases proportionally according to the acceleration of the vehicle, and the passenger can feel the linearity between the vehicle behavior and the effect sound.

[0059] As shown in FIG. 5, when the output of the electric motor is equal to or greater than a predetermined output Wd [kW] (Wd<Wa) and less than a predetermined output Wa [kW], the gain G1 is set to increase as the regeneration amount of the electric motor increases. Thereby, the sound pressure of the effect sound increases proportionally according to the deceleration of the vehicle, and the passenger can feel the linearity between the vehicle behavior and the effect sound.

[0060] As shown in FIG. 5, when the output of the electric motor is less than a predetermined output Wd [kW], the magnitude of the gain G1 is made constant regardless of the regeneration amount of the electric motor. Thereby, the sound pressure of the effect sound does not become too large during vehicle deceleration, and the discomfort of the passenger can be suppressed.

[0061] As described above, the second gain setting unit 38 sets the gain G2 according to the acceleration and deceleration of the vehicle based on the map of FIG. 6.

[0062] As shown in FIG. 6, when the acceleration and deceleration of the vehicle are equal to or greater than a predetermined acceleration and deceleration Aa [G] (Aa<0) and less than a predetermined acceleration and deceleration Ab [G] (Ab>0), the gain G2 is set to increase as the acceleration and deceleration of the vehicle move away from 0 [G]. Thereby, when the vehicle is in the cruise state, the effect sound can be reduced to enhance the quietness in the vehicle interior. Also, when the vehicle behavior changes from the cruise state to the acceleration and deceleration state, the sound pressure of the effect sound can be smoothly changed to give the passenger a sense of unity between the vehicle behavior and the effect sound.

[0063] Also, when the acceleration or deceleration of the vehicle is less than the predetermined acceleration Aa [G], or when the acceleration or deceleration of the vehicle is greater than or equal to the predetermined acceleration Ab [G], regardless of the acceleration or deceleration of the vehicle, the magnitude of the gain G2 is made constant. When the acceleration or deceleration of the vehicle is less than the predetermined acceleration Aa [G], or when the acceleration or deceleration of the vehicle is greater than or equal to Ab [G], regardless of the acceleration or deceleration, the sound pressure of the effect sound changes according to the output of the electric motor.

[0064] As described above, the third gain setting unit 40 sets the gain G3 according to the remaining amount of the battery based on the map of FIG. 7.

[0065] As shown in FIG. 7, the gain G3 when the remaining amount of the battery is equal to or greater than the predetermined amount Qa [%] is smaller than the gain G3 when the remaining amount of the battery is less than the predetermined amount Qa [%]. Thereby, when the battery is close to full charge, the sound pressure of the effect sound becomes smaller. Thereby, when the vehicle is decelerating, a difference can be caused between the sound pressure of the effect sound when the electric motor is regenerating and the sound pressure of the effect sound when the electric motor is not regenerating. Therefore, it is possible to make the occupant recognize that the regeneration of the electric motor is not being performed. When the vehicle is accelerating, the remaining amount of the battery decreases, so there is no difference between the sound pressure of the effect sound when the electric motor is performing power running and the sound pressure of the effect sound when the electric motor is not performing power running.

[0066] Also, as shown in FIG. 7, the gain G3 when the remaining amount of the battery is less than the predetermined amount Qb [%] is smaller than the gain G3 when the remaining amount of the battery is equal to or greater than the predetermined amount Qb [%]. Thereby, when the remaining amount of the battery is almost zero, the sound pressure of the effect sound becomes smaller. Therefore, it is possible to make the occupant recognize that the remaining amount of the battery is almost zero.

[0067] As described above, the fourth gain setting unit 42 sets the gain G4 according to the accelerator pedal opening based on the map of FIG. 8.

[0068] As shown in FIG. 8, when the accelerator pedal opening is less than a predetermined opening Pa [%], the gain G4 is set to increase as the accelerator pedal opening increases. Thereby, the sound pressure of the sound effect increases proportionally according to the accelerator pedal opening, and the linearity between the accelerator pedal operation by the occupant and the sound effect can be felt.

[0069] As shown in FIG. 8, when the accelerator pedal opening is greater than or equal to the predetermined opening Pa [%], the magnitude of the gain G4 is made constant regardless of the magnitude of the accelerator pedal opening. Thereby, when the occupant depresses the accelerator pedal, the sound pressure of the sound effect does not become too large, and the discomfort of the occupant can be suppressed.

[0070] As described above, the fifth gain setting unit 44 sets the gain G5 according to the gradient of the road surface on which the vehicle is traveling based on the map of FIG. 9.

[0071] When the uphill gradient of the road surface is large, the accelerator pedal opening becomes large. Since the sound pressure of the sound effect increases as the accelerator pedal opening increases, when the vehicle is traveling on an uphill gradient, the sound pressure of the sound effect becomes excessive, giving the occupant a sense of discomfort. In the present embodiment, as shown in FIG. 9, the gain G5 is set to decrease as the uphill gradient of the road surface increases. Therefore, even when the vehicle is traveling on an uphill gradient, the sound effect is prevented from becoming excessive, and the discomfort given to the occupant can be reduced.

[0072] When the downhill gradient of the road surface is large, the accelerator pedal opening becomes small. Since the sound pressure of the sound effect decreases as the accelerator pedal opening decreases, when the vehicle is traveling on a downhill gradient, the sound pressure of the sound effect becomes too small. Even though the regenerative brake is generated when the vehicle is traveling on a downhill gradient, the sound pressure of the sound effect becomes too small, giving the occupant a sense of discomfort. In the present embodiment, as shown in FIG. 9, the gain G5 is set to increase as the downhill gradient of the road surface increases. Therefore, even when the vehicle is traveling on a downhill gradient, the sound effect is prevented from becoming too small, and the discomfort given to the occupant can be reduced.

[0073] [Sound effect generation process] FIG. 11 is a flowchart of an effect sound generation process executed in the active effect sound generation device 10 according to the present embodiment. The effect sound generation process is repeatedly executed at a predetermined cycle while the electric vehicle is running.

[0074] In step S1, the first interlocking sound signal generation unit 18 generates a first interlocking sound signal Sa1. Also, the second interlocking sound signal generation unit 20 generates a second interlocking sound signal Sa2. Then, the process proceeds to step S2.

[0075] In step S2, the first background sound signal generation unit 22 generates a first background sound signal Sb1. Also, the second background sound signal generation unit 24 generates a second background sound signal Sb2. Also, the third background sound signal generation unit 26 generates a third background sound signal Sb3. Also, the fourth background sound signal generation unit 28 generates a fourth background sound signal Sb4. Then, the process proceeds to step S3.

[0076] In step S3, the output unit 30 generates an effect sound signal Sc. Also, the output unit 30 outputs the effect sound signal Sc to the speaker 12. In this way, the effect sound generation process is performed.

[0077] 〔Other Embodiments〕 In one embodiment, in each of the first interlocking sound signal generation unit 18 and the second interlocking sound signal generation unit 20, the correction unit 46 multiplies the first interlocking sound signal sa1 and the second interlocking sound signal sa2 generated by the signal generation unit 34 by gains G1 to G5 to generate the first interlocking sound signal Sa1 and the second interlocking sound signal Sa2. On the other hand, the value obtained by multiplying the gains G1 to G5 may be set as the gain G by the gain setting unit 35. Also, the correction unit 46 may multiply the gain G by the first interlocking sound signal sa1 and the second interlocking sound signal sa2 to generate the first interlocking sound signal Sa1 and the second interlocking sound signal Sa2.

[0078] In one embodiment, in each of 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, 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. On the other hand, the gain setting unit 51 may set the value obtained by multiplying the gains G1 to G5 as the gain G. Alternatively, the correction unit 62 may multiply the gain G by 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 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.

[0079] When traveling at the same speed as on flat ground on an uphill slope of the road surface, the output of the electric motor when traveling on the uphill slope is larger than the output of the electric motor when traveling on flat ground. If the gain G is set only according to the output of the electric motor, the gain G increases as the uphill slope of the road surface increases. Therefore, when the vehicle is traveling on an uphill slope, the sound pressure of the sound effect becomes excessive, giving the passenger a sense of discomfort.

[0080] The gain G is set according to at least the output of the electric motor, the acceleration of the vehicle, and the slope of the road surface on which the vehicle is traveling. As shown in FIG. 5, when the output of the electric motor is 0 [kW] or more, the gain G1 increases as the output of the electric motor increases. As shown in FIG. 6, when the acceleration of the vehicle is less than the predetermined acceleration Ab [G], the gain G2 decreases as the acceleration decreases. Also, as shown in FIG. 9, the gain G5 decreases as the uphill slope of the road surface increases.

[0081] Thereby, when the vehicle is cruising at a constant speed on an uphill slope, it is possible to suppress the sound effect from becoming excessive and reduce the discomfort given to the passenger.

[0082] Regarding the above embodiment, the following additional remarks are further disclosed.

[0083] (Appendix 1) The active sound effect generating device (10) of the present disclosure is an active sound effect generating device that outputs a sound effect to a speaker (12) toward the interior of a vehicle driven by an electric motor, and includes a signal generation unit (34) that generates a first sound effect signal which is a signal for outputting the sound effect to the speaker, a gain setting unit (35) that sets a gain according to the amount of regeneration of the electric motor, and an output unit (30) that outputs a second sound effect signal generated by multiplying the gain by the first sound effect signal to the speaker. Thereby, the sound effect can be changed according to the amount of regeneration of the electric motor.

[0084] (Appendix 2) In the active sound effect generating device according to Appendix 1, the gain when the remaining amount of the battery of the vehicle charged by the regenerative power of the electric motor is equal to or more than a predetermined amount may be smaller than the gain when the remaining amount of the battery is less than the predetermined amount. Thereby, the sound effect when the electric motor is regenerating and the sound effect when the electric motor is not regenerating can be made different.

[0085] (Appendix 3) In the active sound effect generating device according to Appendix 1, the gain setting unit may further set the gain according to the gradient of the road surface on which the vehicle is traveling. Thereby, the sound effect can be changed according to the gradient of the road surface on which the vehicle is traveling.

[0086] (Appendix 4) In the active sound effect generating device according to Appendix 1, the gain may be larger as the amount of regeneration is larger. Thereby, the sound effect can be changed according to the amount of regeneration of the electric motor.

[0087] (Appendix 5) In the active sound effect generating device according to Appendix 1, the gain setting unit may further set the gain according to the deceleration of the vehicle, and the gain may be larger as the deceleration is larger. Thereby, the sound effect can be changed according to the deceleration of the vehicle.

[0088] (Appendix 6) In the active sound effect generating device described in Appendix 3, the gain may be smaller as the uphill gradient of the road surface increases, and the gain may be larger as the downhill gradient of the road surface increases. Thereby, it is possible to prevent the sound pressure of the sound effect from becoming excessive while the vehicle is traveling on an uphill gradient. Also, it is possible to prevent the sound pressure of the sound effect from becoming too small while the vehicle is traveling on a downhill gradient.

[0089] (Appendix 7) In the active sound effect generating device described in Appendix 1, the gain setting unit may set the gain according to the output of the electric motor, the gradient of the road surface on which the vehicle is traveling, and the acceleration of the vehicle. Thereby, the sound pressure of the sound effect is adjusted according to the output of the electric motor, the gradient of the road surface, and the acceleration of the vehicle.

[0090] (Appendix 8) In the active sound effect generating device described in Appendix 7, the gain may be larger as the output of the electric motor increases, the gain may be smaller as the uphill gradient of the road surface increases, and the gain may be smaller as the acceleration decreases. Thereby, it is possible to prevent the sound pressure of the sound effect from becoming excessive while the vehicle is traveling on an uphill gradient.

[0091] (Appendix 9) The active sound effect generation method of the present disclosure is an active sound effect generation method for outputting a sound effect from a speaker toward the passenger compartment of a vehicle driven by an electric motor, generating a first sound effect signal which is a signal for outputting the sound effect to the speaker, setting a gain according to the amount of regeneration of the electric motor, and outputting a second sound effect signal generated by multiplying the first sound effect signal by the gain to the speaker. Thereby, the sound effect can be changed according to the amount of regeneration of the electric motor.

[0092] Although the present disclosure has been described in detail, the present disclosure is not limited to the individual embodiments described above. These embodiments can be variously added, replaced, changed, partially deleted, etc., without departing from the gist of the present disclosure or without departing from the spirit of the present disclosure derived from the content described in the claims and its equivalents. Also, these embodiments can 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 examples and are not limited thereto. The same applies when numerical values or mathematical formulas are used in the description of the above-described embodiments.

Description of Reference Numerals

[0093] 10... Active sound effect generation device 12... Speaker 30... Output unit 34... Signal generation unit 35... Gain setting unit

Claims

1. An active sound effect generating device that outputs a sound effect to a speaker toward the interior of a vehicle driven by an electric motor, comprising: a signal generation unit that generates a first sound effect signal, which is a signal for outputting the sound effect to the speaker; a gain setting unit that sets a gain according to the amount of regeneration of the electric motor; an output unit that outputs a second sound effect signal, which is generated by multiplying the gain by the first sound effect signal, to the speaker. The active sound effect generating device is provided with the above components.

2. In the active sound effect generating device according to Claim 1, when the remaining amount of the battery of the vehicle charged by the regenerative power of the electric motor is equal to or more than a predetermined amount, the gain is smaller than the gain when the remaining amount of the battery is less than the predetermined amount. The active sound effect generating device.

3. In the active sound effect generating device according to Claim 1, the gain setting unit further sets the gain according to the gradient of the road surface on which the vehicle is traveling. The active sound effect generating device.

4. In the active sound effect generating device according to Claim 1, the greater the amount of regeneration, the greater the gain. The active sound effect generating device.

5. In the active sound effect generating device according to Claim 1, the gain setting unit further sets the gain according to the deceleration of the vehicle, and the greater the deceleration, the greater the gain. The active sound effect generating device.

6. In the active sound effect generating device according to Claim 3, the greater the uphill gradient of the road surface, the smaller the gain, and the greater the downhill gradient of the road surface, the greater the gain. The active sound effect generating device.

7. In the active sound effect generating device according to Claim 1, the gain setting unit sets the gain according to the output of the electric motor, the gradient of the road surface on which the vehicle is traveling, and the acceleration of the vehicle. The active sound effect generating device.

8. In the active sound effect generating device according to Claim 7, the greater the output of the electric motor, the greater the gain, the greater the uphill gradient of the road surface, the smaller the gain, and the smaller the acceleration, the smaller the gain. The active sound effect generating device.

9. An active sound effect generating method for outputting a sound effect to a speaker toward the interior of a vehicle driven by an electric motor, comprising: generating a first sound effect signal, which is a signal for outputting the sound effect to the speaker, Set a gain according to the amount of regeneration of the electric motor, An active sound effect generation method that outputs a second sound effect signal generated by multiplying the gain by the first sound effect signal to the speaker.

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