JP2022155834A - Sound generation device for vehicles - Google Patents

Abstract

To assist a driver in perceiving a change of the force applied to a vehicle and improve the accuracy of driving operation.SOLUTION: A sound generation device 1 for vehicles comprises: a controller 10 (sound control unit 11) constituted so as to set a plurality of frequencies f1-f5 corresponding to a motor rotation speed R of an electric motor 3 and generate a synthetic sound signal that represents a synthetic sound including sounds S1-S5 of the plurality of frequencies f1-f5, as well as set the localization of the synthetic sound; and a front speaker 20A and a rear speaker 20B capable of outputting a sound that corresponds to the synthetic sound signal the localization of which has been set by the controller 10, at least from the front and the rear of a driver seat of a vehicle 2. The controller 10 sets the localization of the synthetic sound such that the sound image of a low frequency component (e.g., a frequency f1) of the synthetic sound is located at a position behind the driver of the vehicle 2 when an increment ΔT per unit time of a motor torque value T is larger than a prescribed value.SELECTED DRAWING: Figure 5

Description

The present invention relates to a vehicle sound generator, and more particularly to a vehicle sound generator that outputs a predetermined sound while the vehicle is running.

2. Description of the Related Art Conventionally, there has been known a technique of outputting a pseudo engine sound or motor sound to a driver in accordance with the driving state of a vehicle such as vehicle speed and the driver's driving operation such as accelerator opening. (For example, see Patent Document 1 and Patent Document 2).

In the vehicle interior sound field control device described in Patent Document 1, by controlling the signal processing of the sound field control means according to the driving state, the engine sound is reproduced from a plurality of speakers, and the sound field of the engine sound is reproduced. controlled according to the state. As a result, a vivid engine sound that reflects the driving conditions is generated in the passenger compartment.

In addition, in the vehicle active sound effect generator described in Patent Document 2, by giving a delay to the sound effect output from the rear speaker according to the amount of change per unit time of the accelerator opening or the accelerator opening itself, Sound effects that reflect the driver's operation of the accelerator pedal are produced, such as outputting sound effects that take into account the time difference between the intake sound and the exhaust sound, and producing a sense of movement of the sound source.

Japanese Patent Application Laid-Open No. 2007-10810 JP 2013-167851 A

However, the technique of the above-mentioned patent document simply reproduces the sound originally generated by the vehicle, such as the engine sound, and cannot make the driver perceive the change in the force applied to the vehicle.

SUMMARY OF THE INVENTION The present invention has been made in order to solve such problems, and provides a vehicle sound generator that can help the driver perceive changes in the force applied to the vehicle and improve the accuracy of the driving operation. intended to provide.

In order to achieve the above objects, the present invention provides a vehicle sound generating device mounted on a vehicle, which generates a synthesized sound signal representing a synthesized sound containing a plurality of frequencies and sets localization of the synthesized sound. and a sound output unit capable of outputting a sound corresponding to the synthesized sound signal localized by the sound control unit at least from the front and rear of the driver's seat of the vehicle. , the sound control unit is configured to position the sound image of the low-frequency component of the synthesized sound behind the driver of the vehicle when the amount of increase per unit time of the physical quantity correlated with the forward acceleration of the vehicle is greater than a predetermined value. In addition, it is characterized by setting the localization of the synthesized sound.

According to the present invention configured as described above, when the increase amount per unit time of the physical quantity correlated with the forward acceleration of the vehicle is larger than a predetermined value, the sound image position of the low frequency component of the synthesized sound is transmitted to the driver. move backwards. As a result, when the load shifts from the front to the rear of the vehicle with the start of acceleration, the driver can easily perceive this load shift through the movement of the sound image position of the low-pitched sound that gives the impression of weight and power. be able to. That is, it helps the driver to perceive changes in the force applied to the vehicle, thereby improving the accuracy of the driving operation.

Further, in the present invention, preferably, when the amount of increase per unit time of the physical quantity correlated with the forward acceleration of the vehicle is equal to or less than a predetermined value, the sound image position of the low-frequency component is not biased toward the front and rear of the driver. to set the localization of the synthesized sound.
According to the present invention configured as described above, when the vehicle has not started to accelerate and no load shifts from the front to the rear of the vehicle, the position of the sound image for low sounds is not biased to the front and rear of the driver. Therefore, the driver can more easily perceive the movement of the sound image position of the low-pitched sound when the load shifts, and the driver can easily recognize that the sound of the low-frequency component is related to the load shift of the vehicle. can.

In the present invention, the vehicle preferably runs using a rotary power source including an electric motor and/or an engine, and the physical quantity correlated with the forward acceleration of the vehicle is the output torque of the rotary power source.
According to the present invention configured as described above, control is performed using the output torque of the rotary power source, which changes before the acceleration of the vehicle and the suspension stroke. Movement can be perceived by the driver and can help the driver anticipate changes in vehicle behavior.

Further, in the present invention, preferably, the vehicle runs using a rotational power source including an electric motor and/or an engine, and the sound control unit controls an increase per unit time of a physical quantity correlated with forward acceleration of the vehicle. is greater than a predetermined value, the output level of the sound output from the rear of the driver's seat by the sound output unit is set to be higher when the rotation speed of the rotary power source is equal to or less than the predetermined value than when the rotation speed is greater than the predetermined value. do.
According to the present invention configured as described above, when the number of revolutions of the rotary power source is small, that is, when the vehicle starts to move from a stopped state or a steady running state, the driver is particularly aware of the occurrence of a load shift from the front to the rear of the vehicle. It is possible to make the driver more effectively perceive the movement of the sound image position of the low-pitched sound in the scene where it is desired to perceive the low-pitched sound.

Further, in the present invention, preferably, the vehicle runs using a rotational power source including an electric motor and/or an engine, and the sound control section controls the sound output section so as to be proportional to the rotational speed of the rotational power source. Sets the frequency of the sound output from the rear of the seat.
According to the present invention configured in this manner, the acceleration of the vehicle can be recognized by the increase in the audible frequency as the number of revolutions of the rotary power source increases, so the behavior of the vehicle can be more effectively perceived by the driver. can be made

Further, in the present invention, preferably, the vehicle runs using a rotational power source including an electric motor and/or an engine, and the sound control unit sets a plurality of frequencies according to the rotational speed of the rotational power source, The sound output from the sound output unit behind the driver's seat based on a map that defines the relationship between the amount of increase per unit time in the physical quantity correlated with the forward acceleration of the vehicle and the output level of the low frequency among multiple frequencies. The map is set so that when the amount of increase in the physical quantity per unit time is greater than a predetermined value, the output level is higher than when it is not.
According to the present invention configured as described above, in the process of generating the synthesized sound, the determination process such as conditional branching is performed based on the amount of increase per unit time of the physical quantity correlated with the forward acceleration of the vehicle. It is possible to move the sound image position of the low-pitched sound by a simple control of just referring to the map.

According to the vehicle sound generation device of the present invention, it is possible to help the driver to perceive changes in the force applied to the vehicle, thereby improving the accuracy of the driving operation.

1 is an explanatory diagram of a vehicle sound generation device according to an embodiment of the present invention; FIG. 1 is a configuration diagram of a vehicle sound generation device according to an embodiment of the present invention; FIG. FIG. 2 is an explanatory diagram of a basic concept of control by the vehicle sound generation device according to the embodiment of the present invention; FIG. 2 is an explanatory diagram of a basic concept of control by the vehicle sound generation device according to the embodiment of the present invention; FIG. 4 is an explanatory diagram of the flow of sound generation processing in the vehicle sound generation device according to the first embodiment of the present invention; 4 is a flowchart of sound generation processing according to the first embodiment of the present invention; It is a 1st sound pressure level setting map which shows the relationship between motor rotation speed and a sound pressure level of embodiment of this invention. 5 is a second sound pressure level setting map showing the relationship between the motor torque value and the sound pressure level according to the embodiment of the present invention; 4 is a table showing an overview of equalizing processing in sound generation processing according to the first embodiment of the present invention; FIG. 10 is an explanatory diagram of the flow of sound generation processing in the vehicle sound generation device of the second embodiment of the present invention; 9 is a flowchart of sound generation processing according to the second embodiment of the present invention; 8 is a sound pressure level setting map showing the relationship between the motor rotation speed, the motor torque value, the motor torque increase amount, and the sound pressure level in the rear speaker of the second embodiment of the present invention.

A first embodiment and a second embodiment of the present invention will be described below with reference to the accompanying drawings. When there is no particular need to distinguish between these embodiments, they will simply be referred to as "embodiments." When they are distinguished, they will be referred to as "first embodiment" or "second embodiment."

First, with reference to FIGS. 1 and 2, the configuration of the vehicle sound generator of the present invention will be described. FIG. 1 is an explanatory diagram of a vehicle sound generation device, and FIG. 2 is a configuration diagram of the vehicle sound generation device.

As shown in FIGS. 1 and 2, the vehicle sound generation device 1 of the present embodiment includes a controller 10 mounted on a vehicle 2 and a front controller 10 that outputs sound from the front of the driver's seat in the vehicle interior toward the driver's seat. A speaker 20A, a rear speaker 20B that outputs sound from behind the driver's seat toward the driver's seat, and various sensor groups 30 that detect the state of the vehicle 2 are provided.

The vehicle 2 is a vehicle that runs using a rotational power source including an electric motor, an engine, etc. In this embodiment, the vehicle 2 is an electric vehicle (EV) that includes the electric motor 3. may be a hybrid vehicle having both an internal combustion engine and an electric motor, or may be a vehicle having only an internal combustion engine.

The controller 10 is a computer device that includes a processor, a memory (storage unit 12) that stores various programs, a data input/output device, and the like. The controller 10 is communicably connected to other in-vehicle devices via an in-vehicle communication line. The controller 10 is configured to output sound signals to the front speakers 20A and the rear speakers 20B by the processor executing a program based on the vehicle information from the sensor group 30 . At that time, the processor of the controller 10 functions as the sound control section 11 as described below.

The front speaker 20A and the rear speaker 20B are sound output units having amplifiers. The front speaker 20A and the rear speaker 20B receive sound signals from the controller 10, amplify the sound signals with a predetermined amplification factor, and output sounds based on the sound signals. Note that the front speakers 20A and the rear speakers 20B do not have to be provided in the vehicle interior, and it is sufficient if the sounds generated by the front speakers 20A and the rear speakers 20B can be localized to the driver.

The sensor group 30 includes a rotation speed sensor 31 that detects the rotation speed of the electric motor 3 and a PCM 32 that controls the electric motor 3 . These sensors 30 transmit signals indicating detected vehicle information through an in-vehicle communication line. The controller 10 can receive various vehicle information signals from the sensor group 30 via the in-vehicle communication line.

The vehicle information signal includes a motor rotation speed signal S _R and a motor torque value signal S _T . The controller 10 (processor) reads the motor rotation speed R from the motor rotation speed signal S _R and reads the motor torque value T from the motor torque value signal S _T . The motor torque value T is a requested motor torque value (or target motor torque value) for the electric motor 3 .

The PCM 32, like the controller 10, is a computer device equipped with a processor, a memory for storing various programs, a data input/output device, and the like. The PCM 32 receives a vehicle speed signal, an accelerator opening signal, and other signals via an in-vehicle communication line. The PCM 32 stores an acceleration characteristic map (stored in the memory of the PCM 32) that defines the relationship between the accelerator opening, gear stage, etc. (or accelerator opening and its rate of change (accelerator depression speed), gear stage, etc.) and target acceleration. ) is used to calculate the target acceleration from the current accelerator opening. Furthermore, the PCM 32 calculates a required motor torque value (or target motor torque value) for realizing the target acceleration.

In this embodiment, the motor torque value T is the required motor torque value for the electric motor 3, but it is not limited to this, and may be the actual motor torque value actually output by the electric motor 3. . However, the use of the required motor torque value rather than the actual motor torque value can provide the driver with sound output more quickly in response to the driver's accelerator operation, making a greater contribution to the improvement of driving operability. can be expected. In this regard, it is preferable to use the requested motor torque value rather than the actual motor torque value.

Further, in the present embodiment, the controller 10 receives the motor torque value signal S _T from the PCM 32, but the present invention is not limited to this. The motor torque value T may be calculated from

Next, with reference to FIGS. 3A and 3B, control by the vehicle sound generation device 1 of the present embodiment will be described. 3A and 3B are explanatory diagrams of the basic concept of control by the vehicle sound generation device 1 of this embodiment. In FIGS. 3A and 3B, the position of the ellipse conceptually represents the sound image position with respect to the driver, and the size of the ellipse conceptually represents the sound pressure level. The dotted line represents the state before the sound image position and the sound pressure level change, and the solid line represents the state after the change.

FIG. 3A shows the state when the vehicle 2 starts accelerating. When the vehicle 2 starts to accelerate from a stopped state or a state of running at a constant speed, inertial force acts on the center of gravity of the vehicle 2, thereby reducing the load on the front wheels and increasing the load on the rear wheels. That is, a load shift occurs from the front wheels to the rear wheels. At this time, even if the driver can perceive that the vehicle 2 has started accelerating, it is difficult for the driver to perceive the rate of change in acceleration (jerk or jerk) and the movement of the load based only on the sense of equilibrium of the body. Therefore, in the present embodiment, the vehicle sound generation device 1 controls the sound image localization of the sound output from the front speaker 20A and the rear speaker 20B, and changes the arrival direction of the sound to the driver according to the load movement of the vehicle 2. This assists the driver in perceiving changes in force applied to the vehicle.

Specifically, the controller 10 generates a synthesized sound of sounds of a plurality of frequencies, and causes the driver to output this synthesized sound from the front speaker 20A and the rear speaker 20B. Physical quantity correlated with the forward acceleration of the vehicle 2 (e.g. acceleration, motor torque value, rear suspension stroke amount) per unit time increase (e.g. jerk, torque increase, pitch rate in the direction in which the rear suspension sinks) ) is less than or equal to a predetermined value, i.e., when the weight shift from the front to the rear of the vehicle 2 does not occur or is sufficiently small even if it does occur, the controller 10 adjusts the weight and strength of the synthesized sound. The low-frequency components that make us feel are transmitted from the front speaker 20A and the rear speaker 20B so that the sound image position is not biased toward the front and back of the driver (that is, the bass that gives a sense of weight and strength can be heard evenly from around the driver). output. For example, if the difference in sound pressure level before and after the headrest of the driver's seat is less than 4 dB, it can be said that the sound image position is not biased toward the front and rear of the driver. Further, the controller 10 outputs the high-frequency component of the synthesized sound from the front speaker 20A so that the sound image position is in front of the driver (that is, the high-pitched sound can be heard from the front of the driver).

On the other hand, when the amount of increase per unit time of the physical quantity correlated with the forward acceleration of the vehicle 2 is larger than the predetermined value, that is, when the load shifts from the front to the rear in the vehicle 2 as shown in FIG. 3A. , the controller 10 controls the position of the sound image of the low-frequency component of the synthesized sound that gives a sense of weight and power to move behind the driver (that is, if the source of the low-frequency component of the synthesized sound is behind the driver, ), the sound pressure level of the low-frequency component output from the rear speaker 20B is increased. In this way, by moving the sound image position of the low-pitched sound that gives the impression of weight and strength to the rear of the driver, the driver can be made to perceive that the load of the vehicle 2 is moving rearward.

FIG. 3B shows a state in which the vehicle 2 continues accelerating at a constant acceleration after the state of FIG. 3A. That is, since the vehicle 2 has finished moving the load from the front to the rear, the controller 10 controls the sound image position of the low-frequency component of the synthesized sound, which gives a feeling of weight and power, to be not biased toward the front and back of the driver. , output from the front speaker 20A and the rear speaker 20B. Further, as the vehicle 2 continues to accelerate, the load on the electric motor 3 increases, so the controller 10 increases the sound pressure level of the high-frequency component output by the front speaker 20A. This allows the driver to perceive that the load on the electric motor 3 is increasing.

Next, with reference to FIG. 4, the flow of sound generation processing in the vehicle sound generation device 1 of the first embodiment will be described. FIG. 4 is an explanatory diagram of the flow of sound generation processing in the vehicle sound generation device 1 of the first embodiment.

As shown in FIG. 4, the vehicle sound generation device 1 of the first embodiment first sets a plurality of frequencies based on the motor rotation speed R in the sound generation process (frequency setting). Each frequency is set so as to be proportional to the number of revolutions R of the motor. That is, each frequency becomes higher as the motor rotation speed R increases.

Next, the vehicle sound generation device 1 sets the sound pressure level of each set frequency based on the motor rotation speed R and the motor torque value (sound pressure setting). Specifically, a first sound pressure level setting map that defines the relationship between the motor rotation speed R and the sound pressure level is referenced, and the first sound pressure level p1 corresponding to the motor rotation speed R is set for each frequency. , the second sound pressure level setting map that defines the relationship between the motor torque value and the sound pressure level is referred to, and the second sound pressure level p2 corresponding to the motor torque value is set for each frequency. Then, the sum of the first sound pressure level p1 and the second sound pressure level p2 is set as the sound pressure level of the sound of each frequency. Although one first sound pressure level setting map and one second sound pressure level setting map are shown in FIG. 4, actually, the first and second sound pressure level setting maps are shown for each of a plurality of frequencies. are prepared in advance and stored in the storage unit 12 .

Next, the vehicular sound generation device 1 synthesizes the sound of each frequency for which the sound pressure is set, thereby producing a front-channel synthesized sound signal for the front speaker 20A and a rear-channel synthesized sound signal for the rear speaker 20B. and are generated (synthetic sound generation processing). In the first embodiment, both the front channel and rear channel synthesized sound signals are generated by synthesizing sounds of all frequencies set in the sound pressure settings. That is, at this stage, the synthesized sound signal of the front channel and the synthesized sound signal of the rear channel are the same.

Next, the vehicle sound generation device 1 performs equalizing and gain adjustment on each of the synthesized sound signal of the front channel and the synthesized sound signal of the rear channel. At this time, the vehicular sound generation device 1 reduces the sound pressure level of the high frequency components in the synthetic sound signal of the rear channel, thereby setting the localization so that the sound image position of the high frequency components is in front of the driver. In addition, the vehicle sound generator 1 adjusts the sound pressure level of the low-frequency component in the synthetic sound signal of the rear channel based on the amount of increase in the motor torque value, thereby causing a load shift from the front to the rear of the vehicle 2. The localization is set so that the sound image position of the low frequency component is positioned behind the driver when the driver is on.

Then, the vehicle sound generation device 1 outputs the synthesized sound signal _SSF of the front channel after equalization and gain adjustment to the front speaker 20A, and outputs the synthesized sound signal _SSR of the rear channel after equalization and gain adjustment to the rear speaker 20B. output to The front speaker 20A receives the synthesized sound signal _SSF , amplifies it, and outputs it to the driver as a synthesized sound. The rear speaker _20B receives the synthesized sound signal SSR, amplifies it, and outputs it to the driver as a synthesized sound. output to.

Next, sound generation processing of the vehicle sound generation device 1 of the first embodiment will be described with reference to FIGS. 5 to 8. FIG. FIG. 5 is a flowchart of the sound generation process of the first embodiment, FIG. 6 is a first sound pressure level setting map showing the relationship between the motor rotation speed and the sound pressure level of this embodiment, and FIG. 7 is the motor torque of this embodiment. A second sound pressure level setting map showing the relationship between values and sound pressure levels, and FIG. 8 is a table showing an overview of the equalizing process in the sound generation process of the first embodiment.

The vehicle sound generation device 1 repeatedly executes the sound generation process shown in FIG. 5 at predetermined time intervals (for example, every 10 ms).

When the sound generation process is started, the controller 10 first acquires sensor information from the sensor group 30 via the in-vehicle communication line (step S1). As described above, the controller 10 acquires at least the motor rotation speed R and the motor torque value T. FIG.

Next, the controller 10 (sound control unit 11) performs frequency setting processing (step S2). In the frequency setting process, a plurality of frequencies are set based on the number of revolutions R of the motor. Specifically, five frequencies f1 to f5 are set according to the following equations for the motor rotation speed R, which is the primary frequency (fundamental frequency).
fk (Hz) = R (Hz) x nk (Formula 1)

Here, k=1 to 5, and nk is the order with respect to the motor speed R. Specifically, n1 is 3.3, n2 is 4, n3 is 5.3, n4 is 6.7, and n5 is 8, for example. For example, the 3.3rd order frequency f1 is a frequency that is 3.3 times the motor rotation speed R (R (Hz)×3.3). In this embodiment, the fundamental frequency is the motor rotation speed R, but the fundamental frequency is not limited to this, and may be a frequency that increases with an increase in the motor rotation speed R (for example, a proportional relationship).

For example, when the motor rotation speed R is 50 Hz (3000 rpm), the frequency f1 is 165 Hz, the frequency f2 is 200 Hz, the frequency f3 is 265 Hz, the frequency f4 is 335 Hz, and the frequency f5 is 400 Hz.

Next, the controller 10 (sound control unit 11) refers to the first sound pressure level setting map (hereinafter also referred to as “map M1”) stored in the storage unit 12, and based on the motor rotation speed R, each frequency A first sound pressure level p1 is set (step S3). As shown in FIG. 6, the map M1 is set for each of frequencies f1 to f5 of five orders n1 to n5. The map M1 defines the first sound pressure level p1 (dB) of the sounds S1 to S5 of frequencies f1 to f5 with respect to the motor rotation speed R (rpm).

In the map M1, the first sound pressure level p1 generally increases as the motor rotation speed R increases. In this embodiment, the driver can hardly recognize sound with a sound pressure level lower than 40 dB, and can recognize sound with a sound pressure level of 40 dB or higher (audible sound pressure level) as a guideline. Therefore, according to the map M1, for example, at the frequency f4, the motor rotation speed R is less than about 2500 rpm and the first sound pressure level p1 is set to less than 30 dB. Unable to hear S4. Therefore, the driver cannot unconsciously hear the frequency sound of about 30 dB contained in the synthesized sound SC. However, even such a frequency sound of about 30 dB may unconsciously affect the vehicle operation of the driver.

Next, the controller 10 (sound control unit 11) sets the second sound pressure level of each frequency f1 to f5 based on the second sound pressure level setting map (also referred to as “map M2”) stored in the storage unit 12. A level p2 is set (step S4). As shown in FIG. 7, the map M2 is set for each of frequencies f1 to f5 of orders n1 to n5. The map M2 defines the second sound pressure level p2 (dB) at each frequency f1 to f5 with respect to the motor torque value T (N·m). In the map M2, a positive motor torque indicates that the electric motor 3 is operating in a power running state, and a negative motor torque indicates that the electric motor 3 is operating in a regenerative state.

In the map M2, the second sound pressure level p2 is a negative value at each frequency f1 to f5, and the second sound pressure level p2 also increases as the positive motor torque value increases. Therefore, in this embodiment, the first sound pressure level p1 is set by the motor rotation speed R, and when the driver's acceleration request (accelerator operation) is low, the sound pressure level is corrected to be lowered by the second sound pressure level p2. A mixed sound is generated. That is, during acceleration, the higher the motor rotation speed R or the motor torque value T, the higher the output level of the sound output from the front speaker 20A and the rear speaker 20B.

Further, in the map M2, at the frequencies f1 and f3, even if the motor torque value T increases from zero, the second sound pressure level p2 does not increase until the amount of increase in the motor torque value T exceeds a predetermined amount. is set. On the other hand, at frequencies f2, f4, and f5, when the motor torque value T increases from zero, the second sound pressure increases approximately in proportion to the amount of increase in the motor torque value T without waiting for a predetermined amount of increase. The level p2 is set to increase. Therefore, when the driver accelerates the vehicle 2 by operating the accelerator, the sounds of the lower frequencies f1 and f3 are always emphasized and output. That is, during acceleration, at least the sound in the lowest range (k=1) rises quickly, followed by the sounds in the higher range (k=2, 4, 5).

Next, the controller 10 (sound control unit 11) calculates the sum of the first sound pressure level p1 and the second sound pressure level p2 of the sounds S1 to S5 of the frequencies f1 to f5 as the sounds S1 to S5 of the frequencies f1 to f5. By setting the sound pressure level and synthesizing the sounds S1 to S5 of the frequencies f1 to f5 for which the sound pressure is set, the synthetic sound signal SSF of the front channel for the front speaker 20A and the rear channel sound signal _SSF for the rear speaker 20B are obtained. A channel synthesized sound signal _SSR is generated (step S5).

Next, the controller 10 (sound control unit 11) individually performs equalizing processing on the synthesized sound signal _SSF of the front channel and the synthesized sound signal _SSR of the rear channel (step S6).

As shown in FIG. 8, in the equalizing process of the first embodiment, the controller 10 (sound control unit 11) reduces the sound pressure level of high frequency components in the synthetic sound signal _SSR of the rear channel by 40 dB. As shown in FIGS. 6 and 7, the sound pressure level of the synthesized sound is set at a maximum of about 80 dB. Therefore, by reducing the sound pressure level by 40 dB in this equalizing process, the high frequency components of the rear channel can be reduced. The sound pressure level is less than 40 dB. That is, the driver cannot subconsciously hear the high frequency components of the sound output from the rear speaker 20B. As a result, the localization is set so that the sound image position of the high frequency component of the synthesized sound output from the front speaker 20A and the rear speaker 20B is in front of the driver.

In addition, the controller 10 (sound control unit 11) controls the low-frequency component of the synthetic sound signal _SSR of the rear channel by controlling the motor torque value as the amount of increase per unit time of the physical quantity correlated with the forward acceleration of the vehicle 2. Equalizing is performed based on whether or not the amount of increase ΔT of T per unit time is greater than a predetermined value ΔT0. Specifically, when the amount of increase ΔT per unit time of the motor torque value T is equal to or less than the predetermined value ΔT0, that is, the motor torque value T does not increase, or even if it does increase, it is sufficiently small, and the vehicle 2 is driven from the front. When the weight shift to the rear is sufficiently small, the controller 10 (sound control unit 11) does not change the sound pressure level of the low frequency component in the synthetic sound signal _SSR of the rear channel from the value set in step S5.

On the other hand, when the amount of increase ΔT per unit time of the motor torque value T is greater than the predetermined value ΔT0, that is, when the motor torque value T is increasing and the load is shifting from the front to the rear in the vehicle 2, the controller 10 (sound control unit 11) increases the sound pressure level of the low-frequency component in the synthetic sound signal _SSR of the rear channel. At this time, when the motor rotation speed R is equal to or less than a predetermined value R0, equalization is performed so that the sound pressure level of the low-frequency component in the synthesized sound signal _SSR of the rear channel becomes higher than when the motor rotation speed R is greater than R0. process. That is, in the example of FIG. 8, when the increase amount ΔT per unit time of the motor torque value T is larger than ΔT0 (ΔT>ΔT0) and the motor rotation speed R is less than or equal to R0 (R≦R0), the controller 10 (sound control unit 11) increases the sound pressure level of the low-frequency component in the synthetic sound signal _SSR of the rear channel by 30 dB. On the other hand, when the motor rotation speed R is greater than R0 (R>R0), the sound pressure level of the low frequency component in the synthesized sound signal _SSR of the rear channel is increased by 20 dB. As a result, when the load shifts from the front to the rear of the vehicle 2, the sound image position of the low frequency component of the synthesized sound output from the front speaker 20A and the rear speaker 20B is localized so as to be positioned behind the driver. is set. In particular, when the motor rotation speed R is small, the rearward movement of the sound image position of the low frequency components is emphasized.

Further, as shown in FIG. 8, in the equalizing process of the first embodiment, the controller 10 (sound control unit 11) changes the sound pressure level of the synthetic sound signal _SSF of the front channel from the value set in step S5. do not do.

Next, the controller 10 (sound control unit 11) performs gain adjustment processing on each of the synthesized sound signal _SSF of the front channel and the synthesized sound signal _SSR of the rear channel, and adjusts the amplitude of the synthesized sound as a whole for each channel. Adjust (step S7).

Then, the front speaker 20A receives the synthesized sound signal _SSF , performs amplification processing, and outputs it to the driver as a synthesized sound, and the rear speaker _20B receives the synthesized sound signal SSR, performs amplification processing, and outputs it as a synthesized sound. Output to the driver (step S8).

Next, the flow of sound generation processing in the vehicle sound generation device 1 of the second embodiment will be described with reference to FIG. FIG. 9 is an explanatory diagram of the flow of sound generation processing in the vehicle sound generation device 1 of the second embodiment.

As shown in FIG. 9, in the sound generation process, the vehicle sound generation device 1 of the second embodiment first sets a plurality of frequencies for the front channel for the front speaker 20A, and sets a plurality of frequencies for the rear speaker 20B. Setting one or more frequencies for the rear channels (frequency setting). Each frequency is set so as to be proportional to the number of revolutions R of the motor. That is, each frequency becomes higher as the motor rotation speed R increases.

The rear channel frequencies consist of the lower frequencies of the front channel frequencies. For example, the lowest frequency among a plurality of front channel frequencies is set as the rear channel frequency. Alternatively, a frequency lower than the frequency of the front channel may be set. As a result, the high frequency component of the synthesized sound is output only from the front speaker 20A, and the localization is set so that the sound image position of the high frequency component is in front of the driver.

Next, the vehicle sound generation device 1 sets the sound pressure level of each frequency set for the front channel for the front speaker 20A based on the motor rotation speed R and the motor torque value T (sound pressure setting). Specifically, similarly to the first embodiment, the first sound pressure level setting map is referred to, the first sound pressure level p1 corresponding to the motor rotation speed R is set for each frequency, and the second sound pressure level With reference to the setting map, the second sound pressure level p2 corresponding to the motor torque value T is set for each frequency. Then, the sum of the first sound pressure level p1 and the second sound pressure level p2 is set as the sound pressure level of the sound of each frequency in the front channel. Although FIG. 9 shows one each of the first sound pressure level setting map and the second sound pressure level setting map of the front channel, actually, the first and second sound pressure level setting maps are shown for each of the plurality of frequencies of the front channel. 2 A sound pressure level setting map is prepared in advance and stored in the storage unit 12 .

In addition, the vehicle sound generation device 1 adjusts the sound pressure level of the frequency set for the rear channel for the rear speaker 20B to the motor rotation speed R, the motor torque value T, and the increase amount ΔT of the motor torque value T per unit time. (sound pressure setting). Specifically, referring to the first sound pressure level setting map, the first sound pressure level p1 corresponding to the motor rotation speed R is set, and the second sound pressure level setting map is referred to, the motor torque value T , and a third sound pressure level p3 is set according to the increase amount ΔT of the motor torque value T per unit time with reference to the third sound pressure level map. In the third sound pressure level map, the third sound pressure level p3 is set to increase when the amount of increase ΔT per unit time of the motor torque value T is greater than a predetermined value. As a result, the sound pressure level of the low-frequency component of the synthesized sound output from the rear speaker 20B increases when the load shifts from the front to the rear of the vehicle 2, so that the sound image of the low-frequency component of the synthesized sound increases. The orientation is set so that the position is behind the driver.

The sum of the first sound pressure level p1, the second sound pressure level p2, and the third sound pressure level p3 set in this way is set as the sound pressure level of the rear channel sound. In FIG. 9, one each of the first sound pressure level setting map, the second sound pressure level setting map, and the third sound pressure level setting map for the rear channel is shown, but a plurality of maps are shown for the rear channel. When the frequencies are set, the first and second sound pressure level setting maps are prepared in advance for each of the plurality of frequencies, and the third sound pressure level setting map is prepared in advance for at least the lowest frequency, and the storage unit 12 is stored.

Next, the vehicle sound generation device 1 synthesizes the sounds of the respective frequencies of the front channels for which the sound pressure is set, thereby generating the synthesized sound signal _SSF of the front channels for the front speakers 20A. Also, by synthesizing the sound of the rear channel for which the sound pressure is set, the synthetic sound signal _SSR of the rear channel for the rear speaker 20B is generated (synthetic sound generation processing). In the second embodiment, since the frequency set in the frequency setting and the sound pressure level set in the sound pressure setting are different between the front channel and the rear channel, different synthetic sound signals are produced in the front channel and the rear channel. will be generated.

The vehicle sound generation device 1 outputs the synthesized sound signal _SSF of the front channel to the front speaker 20A, and outputs the synthesized sound signal _SSR of the rear channel to the rear speaker 20B. The front speaker 20A receives the synthesized sound signal _SSF , amplifies it, and outputs it to the driver as a synthesized sound. The rear speaker _20B receives the synthesized sound signal SSR, amplifies it, and outputs it to the driver as a synthesized sound. output to.

Next, sound generation processing of the vehicle sound generation device 1 of the second embodiment will be described with reference to FIGS. 10 and 11. FIG. FIG. 10 is a flowchart of sound generation processing of the second embodiment, and FIG. 11 is a relationship between the motor rotation speed R, the motor torque value T, and the motor torque increase amount ΔT in the rear speaker 20B of the second embodiment and the sound pressure level. It is a sound pressure level setting map showing .

The vehicle sound generation device 1 repeatedly executes the sound generation process shown in FIG. 10 at predetermined time intervals (for example, every 10 ms).

When the sound generation process is started, the controller 10 first acquires sensor information from the sensor group 30 via the in-vehicle communication line (step S11). As described above, the controller 10 acquires at least the motor rotation speed R and the motor torque value T. FIG.

Next, the controller 10 (sound control unit 11) performs frequency setting processing (step S12). In the frequency setting process, a plurality of frequencies are set for the front channels for the front speakers 20A and one or more frequencies are set for the rear channels for the rear speakers 20B based on the motor rotation speed R. . For example, for the front channel, five frequencies f1 to f5 are set as in the first embodiment. On the other hand, for the rear channel, frequency f1 is set.

Next, the controller 10 (sound control unit 11) refers to the first sound pressure level setting map (map M1) stored in the storage unit 12, and based on the motor rotation speed R, each frequency set for the front channel and the first sound pressure level p1 of the frequency set for the rear channel are set (step S13).

The first sound pressure level p1 of the front channel is set similarly to the first embodiment. That is, as shown in FIG. 6, based on a map M1 that defines the first sound pressure level p1 (dB) corresponding to the motor rotation speed R (rpm) for each of the five frequencies f1 to f5, the first sound pressure level p1 (dB) of the front channel A sound pressure level p1 is set.

Also, as shown in FIG. 11(a), the first sound pressure level p1 of the rear channel is defined as the first sound pressure level p1 (dB) corresponding to the motor rotation speed R (rpm) for one frequency f1. It is set based on the map M1. This map M1 can be the same as the map M1 for setting the first sound pressure level p1 for the frequency f1 of the front channel.

Next, the controller 10 (sound control unit 11) refers to the second sound pressure level setting map (map M2) stored in the storage unit 12, and based on the motor torque value T, each set for the front channel A second sound pressure level p2 of the frequency and a second sound pressure level p2 of the frequency set for the rear channel are set (step S14).

The second sound pressure level p2 of the front channel is set similarly to the first embodiment. That is, as shown in FIG. 7, based on a map M2 that defines the second sound pressure level p2 (dB) corresponding to the motor torque value T (N·m) for each of the five frequencies f1 to f5, the front channel A second sound pressure level p2 is set.

Further, as shown in FIG. 11B, the second sound pressure level p2 of the rear channel corresponds to the motor torque value T (N·m) for one frequency f1. It is set based on the prescribed map M2. This map M2 can be the same as the map M2 for setting the second sound pressure level p2 for the frequency f1 of the front channel.

Next, the controller 10 (sound control unit 11) refers to the third sound pressure level setting map (map M3) stored in the storage unit 12, and based on the increase amount ΔT of the motor torque value T per unit time, Then, the third sound pressure level p3 of the frequency set for the rear channel is set (step S15). The third sound pressure level p3 of the rear channel is, as shown in FIG. It is set based on a map M3 that defines the sound pressure level p3 (dB).

In the map M3, when the increase amount ΔT per unit time of the motor torque value T is equal to or less than a predetermined value (approximately 250 N·m/s in FIG. 11(c)), the third sound pressure level p3 remains 0 and does not increase. is set to The third sound pressure level p3 is set to increase stepwise by 20 dB when the increase amount ΔT per unit time of the motor torque value T exceeds a predetermined value. Therefore, when the increase amount ΔT per unit time of the motor torque value T exceeds a predetermined value and the load shifts from the front to the rear of the vehicle 2, the low frequency component of the synthesized sound output from the rear speaker 20B Since the sound pressure level of 1 increases, the localization is set so that the sound image position of the low frequency component of the synthesized sound is located behind the driver.

Next, the controller 10 (sound control unit 11) calculates the sum of the first sound pressure level p1 and the second sound pressure level p2 of the sounds S1 to S5 of the frequencies f1 to f5 as the sounds of the frequencies f1 to f5 in the front channel. By setting the sound pressure levels S1 to S5 and synthesizing the sounds S1 to S5 of the frequencies f1 to _f5 for which the sound pressures are set, the synthesized sound signal SSF of the front channel for the front speaker 20A is generated. Further, the controller 10 (sound control unit 11) converts the sum of the first sound pressure level p1, the second sound pressure level p2 and the third sound pressure level p3 of the sound S1 of the frequency f1 to the sound S1 of the frequency f1 in the rear channel. is set as the sound pressure level of , and the synthetic sound signal _SSR of the rear channel for the rear speaker 20B is generated (step S16).

Then, the front speaker 20A receives the synthesized sound signal _SSF , performs amplification processing, and outputs it to the driver as a synthesized sound, and the rear speaker _20B receives the synthesized sound signal SSR, performs amplification processing, and outputs it as a synthesized sound. Output to the driver (step S17).

In the above-described embodiment, when the load is moving from the front to the rear in the vehicle 2, the controller 10 controls the sound image of the sound S1 of the sound S1 of the low frequency component f1 among the plurality of frequencies f1 to f5. Although the localization of the synthesized sound is set so as to be positioned behind the driver, any or all of the sounds S1 to S5 of the frequencies f1 to f5 are positioned behind the driver of the vehicle 2. , the localization of the synthesized sound may be set. In this case, in the first embodiment, the localization of the synthesized sound may be set in the gain adjustment process of step S7 instead of the equalizing process of step S6.

Next, the effects of the vehicle sound generation device 1 of this embodiment will be described.
The vehicle sound generating device 1 of this embodiment is mounted on a vehicle 2 that runs using the electric motor 3 as a rotational power source, and sets a plurality of frequencies f1 to f5 according to the motor rotation speed R of the electric motor 3. , a controller 10 (sound control unit) configured to generate a synthesized sound signal representing a synthesized sound including sounds S1 to S5 of a plurality of frequencies f1 to f5 and to set the localization of the synthesized sound; It has a front speaker 20A and a rear speaker 20B capable of outputting sound corresponding to the synthesized sound signal whose localization is set at least from the front and rear of the driver's seat of the vehicle 2, and the controller 10 (sound control unit 11) , when the increase amount ΔT per unit time of the motor torque value T (physical quantity correlated with the forward acceleration of the vehicle 2) is larger than a predetermined value, the sound image of the low frequency component (for example, frequency f1) The localization of the synthesized sound is set so that it is positioned behind the second driver.

In this embodiment, when the increase amount ΔT per unit time of the motor torque value T (the physical quantity correlated with the forward acceleration of the vehicle 2) is larger than a predetermined value, the low frequency component (for example, the frequency f1 ) is moved behind the driver. As a result, when the load shifts from the front to the rear of the vehicle 2 due to the start of acceleration, the load shift can be easily perceived by the driver through the movement of the sound image position of the bass that gives the driver a feeling of weight and strength. can be made That is, it helps the driver to perceive changes in the force applied to the vehicle, thereby improving the accuracy of the driving operation.

Further, in this embodiment, the higher the rotational speed or output torque of the electric motor 3, the higher the output level of the sound output from the front speaker 20A from the front of the driver's seat. This makes it possible for the driver to easily perceive an increase in vehicle speed due to acceleration and an increase in load on the electric motor 3 .

Further, in the present embodiment, the controller 10 controls the synthesized sound so that the sound image position of the low-frequency component of the synthesized sound is not biased toward the front and back of the driver when the increase amount ΔT per unit time of the motor torque value T is equal to or less than a predetermined value. Sets the sound localization.

With this configuration, in this embodiment, when the vehicle 2 does not start accelerating and no load shifts from the front to the rear of the vehicle 2, the position of the sound image of low sounds is not biased to the front and rear of the driver. Therefore, it is possible to make the driver more easily perceive the shift of the sound image position of the low-pitched sound when the load shift occurs, and to easily make the driver recognize that the sound of the low-frequency component is the sound related to the load shift of the vehicle 2. can.

Further, in this embodiment, the motor torque value T is used as a physical quantity that correlates with the forward acceleration of the vehicle 2 .

With this configuration, in the present embodiment, control is performed using the motor torque value T, which changes before the acceleration of the vehicle 2 or the suspension stroke. can be perceived to help the driver predict changes in the behavior of the vehicle 2 .

Further, in the first embodiment, the controller 10 adjusts the output level of the sound output from the rear speaker 20B from behind the driver's seat when the increase amount ΔT per unit time of the motor torque value T is larger than the predetermined value. When the number R is equal to or less than a predetermined value, the setting is made higher than when the motor rotation speed R is greater than the predetermined value.

With this configuration, in the first embodiment, when the motor rotation speed R is small, that is, when the vehicle 2 starts to move from a stopped state or steady running, the driver is particularly made to perceive that the load shifts from the front to the rear of the vehicle 2. It is possible to make the driver more effectively perceive the movement of the sound image position of the bass sound in the desired scene.

Further, in this embodiment, the controller 10 sets the frequency of the sound output from the rear of the driver's seat by the rear speaker 20B so as to be proportional to the number of revolutions R of the motor.

With this configuration, in the present embodiment, the acceleration of the vehicle can be recognized by the increase in the audible frequency as the motor rotation speed R increases, so the behavior of the vehicle 2 can be more effectively perceived by the driver. .

Further, in the second embodiment, the controller 10 sets a plurality of frequencies f1 to f5 according to the motor rotation speed R, and the increase ΔT per unit time of the motor torque value T and the low frequency among the plurality of frequencies Based on the third sound pressure level setting map that defines the relationship with the output level of f1, the output level of the sound output from the rear speaker 20B from the rear of the driver's seat is set. The output level is set to be higher when the increment ΔT of the value T per unit time is greater than a predetermined value.

With this configuration, in the second embodiment, in the process of generating a synthesized sound, the map is referred to without performing determination processing such as conditional branching based on the magnitude of the increase ΔT of the motor torque value T per unit time. It is possible to realize the movement of the bass sound image position with a simple control.

1 vehicle sound generation device 2 vehicle 3 electric motor 10 controller 11 sound control unit 12 storage unit 20A front speaker 20B rear speaker 30 sensor group 31 revolution sensor 32 PCM
M1 First sound pressure level setting map M2 Second sound pressure level setting map M3 Third sound pressure level setting map

Claims (6)

A vehicle sound generation device mounted on a vehicle,
a sound control unit configured to generate a synthesized sound signal representing a synthesized sound including a plurality of frequencies and to set localization of the synthesized sound;
a sound output unit capable of outputting, from at least in front and behind a driver's seat of the vehicle, a sound corresponding to the synthesized sound signal whose localization is set by the sound control unit;
When the amount of increase per unit time of the physical quantity correlated with the forward acceleration of the vehicle is larger than a predetermined value, the sound control unit causes the sound image of the low frequency component of the synthesized sound to move behind the driver of the vehicle. A vehicular sound generation device, characterized in that the localization of the synthesized sound is set so as to be positioned. When the amount of increase in the physical quantity per unit time is equal to or less than the predetermined value, the sound control unit sets the localization of the synthesized sound so that the sound image position of the low frequency component is not biased in front of or behind the driver. The vehicle sound generator according to claim 1. The vehicle runs using a rotary power source including an electric motor and/or an engine,
the physical quantity is the output torque of the rotational power source;
The vehicle sound generator according to claim 1 or 2. The vehicle runs using a rotary power source including an electric motor and/or an engine,
The sound control unit adjusts the output level of the sound output from behind the driver's seat by the sound output unit when the increase in the physical quantity per unit time is greater than the predetermined value. When the number of rotations is equal to or less than a predetermined value, the number of revolutions is set to be greater than when the number of revolutions is greater than the predetermined value.
The vehicle sound generation device according to any one of claims 1 to 3. The vehicle runs using a rotary power source including an electric motor and/or an engine,
The sound control unit sets the frequency of the sound output by the sound output unit from behind the driver's seat so as to be proportional to the rotation speed of the rotary power source.
The vehicle sound generation device according to any one of claims 1 to 4. The vehicle runs using a rotary power source including an electric motor and/or an engine,
The sound control unit sets the plurality of frequencies according to the rotational speed of the rotational power source, and determines the relationship between the amount of increase in the physical quantity per unit time and the output level of the low frequency among the plurality of frequencies. setting the output level of the sound output from the rear of the driver's seat by the sound output unit based on the prescribed map;
The map is set such that the output level is higher when the amount of increase in the physical quantity per unit time is greater than a predetermined value, compared to when it is not.
The vehicle sound generation device according to any one of claims 1 to 5.

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