JP2006264502A - Engine sound control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To supply an engine sound comfortable for a passenger in a passenger compartment.
In an engine sound control system 10, an engine sound control device 100 detects the characteristics of a music sound emitted from an audio device 11 into a vehicle compartment by a tempo detection unit 120 and a beat amount detection unit 130, respectively. And based on the beat amount. In the audio signal generation unit 150, in order to match the engine sound to the characteristic of the specified music, it is set for the specified characteristic among the orders of the engine sound set in advance in association with the characteristic of the music. The sound signal of the adjustment sound having a frequency corresponding to the order is generated according to the sound pressure level of the music detected by the sound pressure level detection unit 140. The sound signal of the adjustment sound is amplified by the amplifier 14 and finally emitted from the speaker 15 as the adjustment sound.
[Selection] Figure 1

Description

  The present invention relates to a technical field of an engine sound control device for controlling engine sound in a vehicle interior.

  As this type of technology, for example, one that generates a synthesized sound synchronized with engine rotation has been proposed (see, for example, Patent Document 1).

  According to the vehicle interior sound control device disclosed in Patent Document 1 (hereinafter referred to as “conventional technology”), sound characteristics that are appropriately selected by the occupant are given to the synthesized sound, and according to the occupant's preference. It is said that a comfortable engine sound and a sound synchronized with the engine sound can be generated, and a passenger compartment comfortable for passengers can be formed.

  A technique for synthesizing and outputting a specific chord based on the frequency component having the largest sound pressure among engine sounds has also been proposed (see, for example, Patent Document 2).

JP 2000-172281 A JP 2001-290489 A

  The conventional technology can give various sound characteristics to the engine sound by the operation of the occupant. However, if the engine sound is adjusted so as to match the sound in the vehicle interior, for example, music output from the audio, it is frequently used. You have to choose the sound characteristics. This makes it difficult to match the engine sound to the sound in the vehicle interior in a situation where the sound in the vehicle interior can change frequently or indefinitely. Further, there is no guarantee that a sound characteristic consistent with the sound in the passenger compartment is always selected by the passenger. Thus, if the engine sound cannot be matched with the sound in the passenger compartment, the passenger may be uncomfortable. That is, the conventional technique has a technical problem that it is practically difficult to supply a comfortable engine sound to the passenger in the passenger compartment.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide an engine sound control device that can supply engine sound that is comfortable for the passenger in the vehicle interior.

  In order to solve the above-described problems, an engine sound control apparatus according to the present invention is an engine sound control apparatus for controlling engine sound in a vehicle interior of a vehicle including an audio device, and the audio apparatus includes: Characteristic specifying means for specifying the characteristics of music to be emitted into the vehicle interior as an output of the audio device from the sound emission means provided; and the specified frequency band of the engine sound based on the specified characteristics. The audio signal generating means for generating an audio signal having a frequency corresponding to the characteristic, and the audio device are provided so that the sound corresponding to the generated audio signal is emitted into the vehicle interior. And a control means for controlling at least one of the sound emission means and the sound emission means provided in the audio device.

  The “audio device” according to the present invention reads out data or signals relating to music from various recording media such as tape, HD (Hard Disk), CD (Compact Disc), or MD (Mini Disc), and performs various signal processing. It is a concept that encompasses a device or a system for emitting a musical composition via the vehicle interior of the vehicle. In addition, the audio device may be configured as a part of a processing system such as a car navigation system, or by being configured to be connectable to a network such as the Internet, the music data acquired via these networks may be You may have the form which sounds a music based on. In the present invention, “music” is a concept including all music and music information that can be viewed by a user regardless of the genre, such as rock, pop, enka, jazz, or classical music.

  According to the engine sound control apparatus of the present invention, during the operation, the feature specifying means specifies the feature of the music that is emitted into the passenger compartment. The music is emitted from the sound emitting means such as a speaker provided in the audio device into the passenger compartment as the output of the audio device. In addition, the type, performance, and quantity of sound emission means provided in these audio devices are not limited.

  At this time, the feature specifying means may specify the feature of the music by acquiring the value of some item (for example, tempo, beat, etc.) that can define the feature of the music in real time. In this case, the specified characteristic may be the value itself, or each qualitative category classified according to the value (for example, “fast tempo” or “has a beat”). It may be. Alternatively, the feature specifying means may specify the feature of the music by acquiring data representing the feature itself, not based on such a value. Note that the feature of the music specified by the feature specifying means may include a property given by the audio device. For example, the volume and sound quality may be included. The feature specified by the feature specifying means may not be one for one music piece.

  The characteristics of the music may not necessarily be specified based on the music emitted in the passenger compartment. For example, if a signal or data relating to a music piece is being processed in the audio device, and if it is possible to acquire data representing the value of the item or the feature itself based on the signal or data, the method is performed. Based on the values and data acquired in this way, the characteristics of the music may be specified before the music is emitted as sound. Alternatively, if data representing the characteristics of a song is supplied via a network or the like and the data can be obtained via the network by the audio device, the characteristics of the song are specified based on such data or the like. May be.

  When the characteristics of the music are specified, an audio signal having a frequency corresponding to the specified characteristics in the engine sound frequency band is generated by the audio signal generation means.

  The frequency band of the engine sound includes a frequency corresponding to the music feature. The frequency having such a correspondence includes, for example, a frequency at which the music feature can be further emphasized and a frequency at which the music feature is inhibited. Therefore, by adjusting the engine sound based on the sound having a frequency having this correspondence relationship, it becomes possible to match the engine sound to the characteristics of the music. The sound signal generated by the sound signal generating means is a sound signal related to the sound for adjusting the engine sound to match the feature of the music in this way, and is generated based on the feature specified by the feature specifying means. Is done. By adjusting the engine sound to match the characteristics of the music, the engine sound matches the sound in the passenger compartment. Hereinafter, such a sound for adjusting the engine sound to match the sound in the passenger compartment will be referred to as “adjustment sound” as appropriate.

  For example, if the phase of the adjustment sound having a certain frequency is shifted by 180 degrees from the phase of the engine sound having the frequency, the engine sound is canceled and attenuated by the adjustment sound. Conversely, if the phase of the adjustment sound is the same as the phase of the engine sound, the engine sound is emphasized and amplified by the adjustment sound. Further, when the volume as one of the features of the music is large, the signal level of the audio signal can be increased regardless of cancellation or emphasis. If the volume is small, the signal level may be small. Thus, the audio signal generation means generates an audio signal based on the identified feature. The engine sound control apparatus according to the present invention may be equipped with a DSP (Digital Signal Processor) or the like for performing the signal processing of the adjustment sound.

  The correspondence between the characteristics of the music and the frequency of the engine sound may be determined in advance experimentally, empirically, or by simulation, or may be determined by some algorithm each time. When the correspondence relationship is predetermined, data corresponding to the correspondence relationship related to some storage means may be stored.

  When the audio signal is generated, the control unit emits the sound corresponding to the generated audio signal into the vehicle interior, and the sound output unit provided separately from the audio device and the release provided in the audio device. At least one of the sound means is controlled. That is, the adjustment sound is emitted by some sound emitting means that can emit sound into the passenger compartment.

  As described above, the adjustment sound is a sound having a frequency corresponding to the characteristic of the specified music in the frequency band of the engine sound, and the signal level (sound pressure) or phase of the music is specified. The sound is determined based on the characteristics. For this reason, in the vehicle interior, the engine sound and the adjustment sound interact with each other, for example, an engine sound having a certain frequency is emphasized. Or the engine sound of a certain frequency attenuates. As a result, for example, an engine sound that increases the force when an energetic musical piece is flowing into the passenger compartment, or an engine sound that is attenuated as a whole when a quiet musical piece is flowing can be supplied. . As described above, according to the engine sound control apparatus of the present invention, the engine sound in the vehicle interior is efficiently matched to the music that is one of the sounds in the vehicle interior, so that it is comfortable for the passenger in the vehicle interior. It is possible to supply engine sound.

  In one aspect of the engine sound control apparatus according to the present invention, the engine sound control device further includes sound collecting means for collecting engine sound in the vehicle interior, and the sound signal generating means is configured to perform the sound generation based on the collected engine sound. Generate an audio signal.

  According to this aspect, the engine sound in the passenger compartment is collected by sound collecting means such as a microphone (hereinafter referred to as “microphone” as appropriate), and a sound signal is generated based on the collected engine sound. Is done. That is, feedback control is performed. Therefore, it becomes possible to match the engine sound with the sound in the passenger compartment with relatively high accuracy and efficiency.

  In another aspect of the engine sound control apparatus according to the present invention, the engine sound control device further includes a music feature amount acquisition unit that acquires a music feature amount quantified for each predetermined feature item, and the feature specifying unit includes: The feature of the music is specified based on the music feature.

  In the present invention, the “feature item” is a parameter prepared in advance to represent the characteristics of the music. For example, the characteristics of the music such as “tempo”, “beat”, or “pitch” are used as physical numerical values. Refers to a replaceable item. The music feature amount means such a value of each parameter. In addition, as long as it is not contrary to the meaning, the kind and quantity of the feature item according to the present invention are not limited at all. Moreover, the aspect of the music feature amount specifying means for specifying such a music feature amount may be freely determined as appropriate.

  According to this aspect, since the feature of the music is specified based on such a music feature amount, it is possible to specify the feature of the music relatively accurately.

  In this aspect, the feature item may include at least one of a tempo and a beat in the music. The tempo or beat is an item that can largely define the characteristics of the music among the characteristic items that can quantitatively (numerically) express the characteristics of the music. By acquiring these music features, the music It is possible to suitably acquire the characteristics.

  In another aspect of the engine sound control apparatus according to the present invention, the frequency corresponding to the specified feature is set in advance for each feature of the music as defining the frequency of the engine sound to be emphasized or attenuated. Of the orders of the engine sound, the frequency corresponds to the order corresponding to the specified feature.

  According to this aspect, the order of the engine sound is set in advance for each feature of the music as defining the frequency of the engine sound to be emphasized or attenuated.

  The “order of engine sound” according to the present invention refers to the ratio between the engine speed and the vibration frequency. For example, in the case of a general four-cylinder four-cycle engine, four explosions occur during two revolutions of the crankshaft, so the basic engine sound order is “2”. Hereinafter, among the engine sounds, a sound corresponding to a frequency whose engine sound order is “N” is appropriately referred to as “Nth engine sound”. In a four-cylinder four-cycle engine, the engine sound is formed including the various harmonics (for example, the fourth-order engine sound, the sixth-order engine sound, etc.) based on the second-order engine sound. In the case of a 6-cylinder 4-cycle engine, the order of the basic engine sound is 3. That is, the tertiary engine sound is fundamental.

  For example, taking the tempo as described above as an example, for a song with a sense of tempo (a song with a fast tempo), in the case of a four-cylinder engine, the second, fourth and sixth engine sounds are emphasized. Can make such a sense of tempo stand out. Therefore, in this case, the second order, the fourth order, and the sixth order may be set to define the frequencies to be emphasized. In addition, if the music has a beat feeling, these second-order, fourth-order, and sixth-order engine sounds, and further half-order engine sounds, for example, 2.5th-order, third-order, 3.5th-order, and 4.5th By emphasizing the engine sound such as the following, the beat feeling can be emphasized. Alternatively, in the case of music that does not have a sense of tempo or a beat, the engine sound of the above order does not match the music, so that the characteristics of the music can be prevented from being impaired by attenuation. Here, “preset” indicates that, for example, information specifying the order of the engine sound is stored for each feature of the music. At this time, the mode of the storage means for storing such information is not particularly limited as long as it can be directly or indirectly referred to by the audio signal generation means. Note that the correspondence between the characteristics of the music, the order of the engine sound, and the mode of increase / decrease control thereof may be determined in advance experimentally, empirically, or based on simulation, for example. Good. Further, as described above, the number of engine sound orders set for each music feature is not limited.

  Here, the frequency corresponding to the order of the engine sound changes in accordance with the engine speed. Therefore, in this case, for example, the engine speed may be specified based on a pulse signal synchronized with engine rotation, such as a crank pulse or an ignition pulse, and the frequency may be specified based on the engine speed.

  According to this aspect, since the order of the engine sound is set in advance for each feature of the music as defining the frequency of the adjustment sound (that is, the engine sound to be emphasized or attenuated), the sound signal generating means The sound signal of the adjustment sound may be generated so as to have a frequency corresponding to the order corresponding to the identified feature. Therefore, the engine sound in the passenger compartment can be matched to the music simply and effectively.

  In order to solve the above-described problem, another engine sound adjustment device according to the present invention is an engine sound control device for controlling engine sound in a vehicle interior of a vehicle including an audio device, wherein the audio A first frequency characteristic specifying means for specifying a frequency characteristic of music to be emitted into the vehicle interior as an output of the audio device from a sound emitting means provided in the apparatus; and the engine based on the frequency characteristic of the specified music An audio signal generating means for generating an audio signal having a frequency to be adjusted in a frequency band of sound, and the audio device so that sound corresponding to the generated audio signal is emitted into the vehicle interior. And a control means for controlling at least one of the sound emitting means provided separately and the sound emitting means provided in the audio device. To.

  According to another engine sound control apparatus according to the present invention, the frequency characteristic of the music that is the output of the audio device is specified by the first frequency characteristic specifying means.

  Here, the frequency characteristic of the music is a characteristic in the frequency domain of the audio signal of the music. Such frequency characteristics may be specified by, for example, an apparatus or system including an FFT (Fast Fourier Transfer) analyzer. The sound signal generation means generates a sound signal having a frequency to be adjusted in the frequency band of the engine sound based on this frequency characteristic. Note that the frequency characteristics of the music may be specified sequentially in real time, every cycle that is short enough to be regarded as real time, or may be specified every certain time interval.

  Here, the “frequency to be adjusted” is the frequency of the sound for adjusting the engine sound so as to match the frequency characteristic of the music, that is, the frequency of the adjustment sound described above. The frequency of the adjustment sound may be set in advance in association with the frequency characteristics of the music, or may be determined as appropriate according to the frequency characteristics of the music each time. When such a frequency to be adjusted is set in advance, the frequency may be set experimentally, empirically, or based on simulation. If the frequency to be adjusted is set in advance, the frequency characteristics of the music may be grouped in advance, and the frequency to be adjusted may be assigned to each group.

  The audio signal generation means generates an audio signal having such a frequency to be adjusted based on the frequency characteristics of the music. For example, if the frequency characteristic of the music at a certain point is sinusoidal, a frequency corresponding to a relatively large amplitude in the frequency band of the engine sound can be set to a relatively high output. . Therefore, it is not necessary to adjust the engine sound, or an adjustment sound whose phase is matched with the engine sound may be appropriately added. On the other hand, it is preferable to actively attenuate a frequency corresponding to a relatively small amplitude. In this case, an adjustment sound having an opposite phase to the engine sound may be added to the engine sound.

  When the sound signal of such adjustment sound is generated, the adjustment sound is emitted from some sound emission means provided in the passenger compartment, and the engine sound is adjusted. As described above, according to another engine sound adjustment device according to the present invention, the engine sound is efficiently matched with the frequency characteristic of the music, which is one of the sounds in the vehicle interior, so that it is comfortable for the passenger in the vehicle interior. Therefore, it is possible to supply a simple engine sound.

  In another aspect of the engine sound adjusting apparatus according to the present invention, the engine sound adjusting device further includes a second frequency characteristic specifying unit that specifies a frequency characteristic of the engine sound, and the sound signal generating unit includes the frequency of the specified music piece. The voice signal is generated based on a comparison between a characteristic and a frequency characteristic of the identified engine sound.

  According to this aspect, the frequency characteristic of the engine sound is specified by the second frequency characteristic specifying unit. Here, the second frequency characteristic specifying means may include the above-described FFT analyzer and the like. In this case, for example, the characteristics in the time domain of the engine sound collected by the sound collecting means such as a microphone may be converted into the characteristics in the frequency domain.

  The sound signal generation means generates a sound signal of the adjustment sound based on a mutual comparison between the frequency characteristic of the music and the frequency characteristic of the engine sound. Here, “based on mutual comparison” is not limited to an aspect as long as the result of the mutual comparison and the sound signal of the adjustment sound are in some correspondence. For example, feedback control may be performed so that the frequency characteristic of the engine sound approaches the frequency characteristic of the music.

  In another aspect of the engine sound adjusting device according to the present invention, the frequency to be adjusted includes a frequency corresponding to the order of the engine sound.

  According to this aspect, the frequency to be adjusted, that is, the frequency of the adjustment sound includes the frequency corresponding to the order of the engine sound. Since the frequency corresponding to the order of the engine sound is a frequency resulting from the explosion of the engine, the engine sound corresponding to this frequency occupies a large position in the entire engine sound. Therefore, the frequency to be adjusted includes the frequency corresponding to the order of the engine sound, so that the engine sound can be efficiently adapted to the frequency characteristics of the music. For example, among the orders of engine sound, as described above, engine sounds corresponding to the second, fourth and sixth orders (in the case of four cylinders) fall into the category with the highest sound pressure level. Therefore, it is possible to adjust the engine sound suitably.

  In order to solve the above-described problem, still another engine sound control apparatus according to the present invention is an engine sound control apparatus for controlling engine sound in a vehicle compartment of a vehicle, and specifies a frequency characteristic of the engine sound. Based on the difference between the frequency characteristic specifying means, the moving average calculating means for calculating the specified frequency characteristics, and the difference between the moving average and the specified frequency characteristics, the frequency band of the engine sound is adjusted. Audio signal generating means for generating an audio signal having a frequency to be used, and control means for controlling a predetermined sound emitting means so that sound corresponding to the generated audio signal is emitted into the room. It is characterized by that.

  According to this aspect, the frequency characteristic of the engine sound is specified by the frequency specifying means. The moving average calculating means calculates a moving average of the frequency characteristic.

  Such a frequency characteristic of the engine sound may be specified through a device or system including an FFT analyzer or the like from a time-domain sound signal collected by sound collecting means such as a microphone. In the frequency characteristic of the engine sound, suddenly generated sound or conversation in the passenger compartment becomes so-called random noise, and thus attenuates to a level that does not need to be taken into consideration in the moving average. Therefore, a significant signal in the moving average of such frequency characteristics may be considered almost purely as engine sound. The calculated moving average represents a sound that constantly exists in the passenger compartment.

  This moving average naturally changes depending on the engine speed, but if attention is paid to one engine speed, if the engine sound is always approximated to this moving average, the sound in the passenger compartment is always kept uniform. Is done. In this case, it is comfortable for the passenger. However, the sound pressure of the engine sound always fluctuates indefinitely due to minute changes such as the explosion state of the engine. For example, in the moving average, the sound pressure level of the engine sound at a certain point in time is higher than the sound pressure level at a certain frequency, and the engine sound pressure level at a certain point of time tends to vary.

  Therefore, the audio signal generation means generates an audio signal having a frequency to be adjusted based on the difference between the identified frequency characteristic and the calculated moving average. The audio signal having the frequency to be adjusted is an audio signal of an adjusted sound.

  How the sound signal of the adjustment sound is determined is not limited as long as the frequency characteristic of the engine sound approaches the moving average to some extent. For example, in the specified frequency characteristic, an audio signal may be generated in which the engine sound is attenuated for a frequency that is higher than the moving average and the engine sound is increased for a frequency that is lower than the moving average.

  The sound corresponding to the generated sound signal (that is, the adjustment sound) is emitted into the passenger compartment by a predetermined sound emission means, and the engine sound is adjusted to match the moving average. Therefore, the engine sound in the passenger compartment is eliminated from indefinite changes, and only changes linearly according to the engine speed, making it comfortable for the passenger. That is, it is possible to supply engine sound that is comfortable for the occupant in the passenger compartment.

  The moving average may be acquired, for example, when the vehicle travels for the first time, and may be stored in an appropriate storage unit in a form that can be referred to later. This is preferable because it is not necessary to calculate the moving average every time the vehicle is driven.

  The moving average may be updated as appropriate. For example, if the frequency characteristic of the engine sound specified in real time and the moving average are too large, the load applied to the sound signal generating means will be large, and the moving average itself will be the sound inside the vehicle ( The target value may not be eligible. In such a case, for example, the moving average may be learned again when the deviation from the frequency characteristic of the engine sound to be specified becomes a predetermined value or more.

  Such an operation and other advantages of the present invention will become apparent from the embodiments described below.

<Embodiment of the Invention>
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

<First Embodiment>
<Configuration of Embodiment>
First, the configuration of the engine sound control system according to the first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a block diagram of the engine sound control system 10.

  In FIG. 1, an engine sound control system 10 includes an audio device 11, a pulse detection unit 12, a microphone 13, an amplifier 14, a speaker 15, and an engine sound control device 100, and is a system for controlling engine sound in a vehicle cabin of a vehicle. It is.

  The audio device 11 is a device configured to be able to emit music in the passenger compartment. The audio device 11 emits music from a speaker (not shown) provided in the audio device 11.

  The engine pulse detection unit 12 is configured to be able to detect an engine ignition pulse.

  The microphone 13 is an example of the “sound collecting means” according to the present invention, which is installed to collect engine sound in the vehicle interior. The microphone 13 is configured to be able to supply an electric signal corresponding to the collected engine sound to the engine sound control apparatus 100.

  The amplifier 14 is an amplifier that amplifies a sound signal of an adjustment sound, which will be described later, output from the engine sound control apparatus 100. The amplifier 14 is installed separately from the audio device 11.

  The speaker 15 is an example of “sound emitting means provided separately from the audio device” according to the present invention, which is configured to be able to emit the adjustment sound into the vehicle interior.

  The engine sound control apparatus 100 includes a control unit 110, a tempo detection unit 120, a beat detection unit 130, a sound pressure level detection unit 140, and an audio signal generation unit 150.

  The control unit 110 includes a CPU (Central Processing Unit) 111, a ROM (Read Only Memory) 112, and a RAM (Random Access Memory) 113.

  The CPU 111 is a control unit that controls the operation of the engine sound control unit 100. The ROM 112 stores an engine sound control program for controlling the engine sound. The CPU 111 reads the engine sound control program from the ROM 112 and executes engine sound control processing to control the engine sound. It is configured to be possible. The RAM 113 is configured to be able to temporarily store various data generated in the process in which the CPU 111 executes the engine sound control process.

  The tempo detection unit 120 is configured to be able to detect the tempo of music that is emitted from the audio device 11 into the passenger compartment by quantifying it.

  The beat detection unit 130 is configured to be able to detect and digitize the beat of the music emitted from the audio device 11 into the passenger compartment.

  The sound pressure level detection unit 140 is configured to be able to detect and digitize the sound pressure level of the music emitted from the audio device 11 into the passenger compartment.

  The audio signal generation unit 150 is configured to be able to generate an audio signal related to the adjustment sound for adjusting the engine sound.

<Operation of Embodiment>
In the engine sound control system 10, the engine sound control device 100 executes the engine sound control process, whereby the engine sound can be matched with the music emitted from the audio device 11 into the vehicle interior. Here, the details of the engine sound control process will be described with reference to FIG. FIG. 2 is a flowchart of the engine sound control process.

  In FIG. 2, the CPU 111 first determines whether or not music is being emitted in the passenger compartment (step A10). When the music is not emitted in the passenger compartment (step A10: NO), the CPU 111 waits until the music emission is started.

  When the music is being emitted (step A10: YES), the CPU 111 executes various processes for specifying the characteristics of the emitted music as parallel processing.

  That is, the CPU 111 instructs the tempo detection unit 120 to detect the tempo of the music. Upon receiving such an instruction, the tempo detection unit 120 detects the tempo of the music. Further, the CPU 111 instructs the beat amount detection unit 130 to detect the beat amount of the music. Upon receiving this instruction, the beat amount detection unit 130 detects the beat amount of the music. When detecting these tempos and beats, specifically, an audio signal related to music is acquired from the audio device 11 through a low-pass filter that separates 200 Hz or less, and the time interval and level protrusion regarding the base drum are analyzed. The

  Further, the CPU 111 instructs the sound pressure level detection unit 140 to detect the sound pressure level of the music. In response to the instruction, the sound pressure level detection unit 140 detects the sound pressure level of the music. These detection results are temporarily stored in the RAM 113.

  When these parallel processes are completed, the CPU 111 identifies the characteristics of the music from the results of these parallel processes stored in the RAM 113 (step A14). At this time, the tempo and the beat amount are classified into a plurality of stages according to a predetermined standard, and the characteristics of the music composition are comprehensively determined based on the stages classified for each of the tempo and the beat amount. The reference is stored in the ROM 112 in advance. In addition, the sound pressure level among the characteristics of the music is used as a judgment material for determining the sound pressure level of the adjustment sound.

  When the characteristics of the music are specified, the CPU 111 instructs the audio signal generation unit 150 to generate the audio signal of the adjustment sound, and the audio signal generation unit 150 outputs the audio of the adjustment sound based on the instruction. A signal is generated (step A15).

  In the present embodiment, the “adjustment sound” refers to a sound added to the engine sound in order to adjust the engine sound. Here, the details of the adjustment sound will be described with reference to FIG. FIG. 3 is a table illustrating the correspondence between the characteristics of the music and the order of the engine sound.

  In FIG. 3, the characteristics of the music are shown as three types: “with a beat feeling”, “with a beat feeling and a tempo feeling”, and “without a beat feeling and a tempo feeling”. Here, “there is a feeling of beat” refers to a state in which the beat amount of the music detected by the beat amount detection unit 130 is larger than the reference. Further, “with a sense of tempo” refers to a state in which the tempo of the music detected by the tempo detection unit 120 is faster than the reference. Further, “no sense of beat and no sense of tempo” refers to a state where the amount of beat and the tempo are smaller and slower than the reference, respectively.

  In the case of music with a beat feeling, it is possible to further emphasize the beat feeling of the music by emphasizing the second, fourth and sixth engine sounds among the engine sounds. Therefore, the CPU 111 emphasizes the secondary, fourth, and sixth engine sounds for the audio signal generation unit 150 when the music emitted in the passenger compartment is a music with a sense of beat. A signal instructing generation of the adjustment sound is transmitted.

  If there is a sense of tempo in addition to the beat feeling, in addition to the above-mentioned second, fourth and sixth order engine sounds, half order, for example, 2.5th order, 3rd order, 3.5th order and 4.5th order By emphasizing the engine sound, it is possible to emphasize the tempo feeling in addition to the beat feeling. Accordingly, when the music being emitted into the passenger compartment is a music with a sense of tempo in addition to the beat feeling, the CPU 111 instructs the audio signal generation unit 150 to perform the second, fourth, sixth and half orders. A signal for instructing generation of an adjustment sound for enhancing the engine sound is transmitted.

  In addition, when there is neither a feeling of beat nor a feeling of tempo, there is a high possibility that the above-mentioned second, fourth, sixth and half order engine sounds do not match the characteristics of the music. Therefore, when the music emitted in the passenger compartment is a music without a feeling of beat and tempo, the CPU 111 instructs the audio signal generation unit 150 to use the adjustment sound for attenuating the engine sound of the order. A signal instructing generation is transmitted.

  Information regarding the order of the engine sound that defines the frequency of the adjustment sound is stored in advance in the ROM 112 for each characteristic of the music, and the CPU 111 specifies the specified information from the ROM 112 when the characteristics of the music are specified. The one corresponding to the feature is selected, and the audio signal generation unit 150 is instructed to generate the adjustment sound. However, the frequency of the adjustment sound may be determined by the CPU 111 according to some algorithm each time according to the characteristics of the specified music.

  When instructing the generation of these adjustment sounds, the CPU 111 further refers to the sound pressure level of the music detected by the sound pressure level detection unit 140 and designates the sound pressure of the adjustment sound. For example, the CPU 111 has a relatively high sound pressure of the adjustment sound when the sound pressure level of the music is relatively high, and also has a relatively low sound pressure of the adjustment sound when the sound pressure level of the music is relatively low. An instruction is issued to the audio signal generation unit 150.

  On the other hand, the frequency of the adjustment sound corresponding to the engine order varies with the engine speed. Here, the details of the order of the engine sound will be described with reference to FIG. FIG. 4 is a schematic diagram for explaining the order of the engine sound.

  In FIG. 4, the horizontal axis represents the engine sound frequency, and the vertical axis represents the engine speed. In this coordinate system, the characteristics of the second-order, fourth-order, and sixth-order engine sounds are shown by solid lines in the figure. Moreover, the thing corresponding to the half order mentioned above is drawn with the broken line. For example, the frequency of the secondary engine sound that is the basic sound of the engine sound is 100 Hz when the engine speed is 3000 rpm, and the frequency of the fourth-order engine sound that is the second harmonic is 200 Hz. is there. Accordingly, when adjusting the secondary engine sound when the engine speed is 3000 rpm, the CPU 111 instructs the audio signal generation unit 150 to generate a 100 Hz audio signal. In accordance with this, the audio signal generation unit 150 generates an audio signal of 100 Hz.

  As described above, when generating a sound signal having a frequency corresponding to the order of the engine sound, it is necessary to know the engine speed. Therefore, in step A15 in FIG. 2, the CPU 111 obtains an engine ignition pulse from the pulse detector 120 and calculates the engine speed.

  Returning to FIG. 2, when the sound signal of the adjustment sound is generated, the generated sound signal is amplified by the amplifier 14 and then emitted from the speaker 15 as the adjustment sound into the vehicle interior (step A16).

  Here, the mode of interference of the engine sound is determined by the relative relationship between the phase of the adjustment sound emitted from the speaker 15 and the phase of the engine sound. For example, when the phase of the engine sound matches the phase of the adjustment sound, they interfere with each other and the engine sound is emphasized. If these phase differences are 180 degrees, they weaken each other and the engine sound is attenuated.

  Therefore, the CPU 111 performs feedback control based on the engine sound in the passenger compartment collected by the microphone 13. That is, when emphasizing the secondary engine sound, the audio signal generation unit 150 generates an audio signal having a frequency corresponding to the secondary engine sound and having a predetermined sound pressure level. Regarding the phase of the signal, the engine sound in the passenger compartment input from the microphone 13 is referred to control the phase so that the secondary engine sound is most emphasized.

  When the adjustment sound is emitted into the passenger compartment, the process returns to step A10 again. When the sound emission of the music continues, the above process is looped.

  As described above, according to the engine sound control apparatus 100, the adjustment sound for adjusting the engine sound of the predetermined order so as to match the characteristics of the music emitted in the vehicle interior is emitted into the vehicle interior. Can do. Therefore, in the passenger compartment, for example, it is possible to easily emphasize the dynamic feeling, emphasize the force, and produce a sense of silence according to the characteristics of the music. Therefore, it is possible to supply engine sound that is comfortable for the occupant in the passenger compartment.

<Second Embodiment>
In the first embodiment, the engine sound is matched with the music in the passenger compartment by specifying the characteristics of the music, but there are other methods for matching the music with the music. Here, the second embodiment of the present invention will be described.

  First, the configuration of the engine sound control system according to the second embodiment of the present invention will be described with reference to FIG. FIG. 5 is a block diagram of the engine sound control system 20. In the figure, the same reference numerals are given to the same portions as those in FIG. 1 described above, and the description thereof is omitted.

  In FIG. 5, the engine sound control system 20 is different from the engine sound control system 10 according to the first embodiment in that an engine sound control apparatus 200 is provided instead of the engine sound control apparatus 100.

  The engine sound control apparatus 200 includes a control unit 110, a first frequency characteristic specifying unit 210, a second frequency characteristic specifying unit 220, a difference calculating unit 230, and an audio signal generating unit 150.

  The control unit 110 is similar to the first embodiment in terms of hardware, and the engine sound control process executed by the CPU 111 is configured differently from the first embodiment.

  The first frequency characteristic specifying unit 210 is configured to be able to acquire an audio signal of music from the audio device 11 and specify the frequency characteristic.

  The 2nd frequency characteristic specific | specification part 220 is comprised so that the audio | voice signal regarding the engine sound in a vehicle interior can be acquired from the microphone 13, and the frequency characteristic can be specified.

  The difference calculation unit 230 is a calculator that calculates the difference between the frequency characteristic of the music specified by the first frequency characteristic specifying unit and the frequency characteristic of the engine sound specified by the second frequency characteristic specifying unit. Here, the difference in frequency characteristics means a difference in component amount at each frequency in a frequency band that defines the frequency characteristics.

  Under such a configuration, the engine sound control apparatus 200 matches the engine sound to the music piece by the CPU 111 executing the engine sound control process. Here, with reference to FIG. 6, the details of the engine sound control process will be described as the operation of the engine sound control apparatus 200. FIG. 6 is a flowchart of the engine sound control process. 6 that are the same as those in FIG. 2 are denoted by the same reference numerals and description thereof is omitted.

  In FIG. 6, when the music is being emitted (step A10: YES), the CPU 111 controls the first frequency characteristic specifying unit 210 and the second frequency characteristic specifying unit 220 to specify the frequency characteristics of the music ( Step B10) and identification of the frequency characteristics of the engine sound (step B11) are performed. The frequency characteristic of the engine sound is such that the sound pressure level becomes relatively large at a frequency corresponding to the engine sound of each order.

  Here, with reference to FIG. 7, the details of the frequency characteristic of the music specified by the first frequency characteristic specifying unit 210 will be described. FIG. 7 is an illustration of the frequency characteristics of music.

  In FIG. 7, the vertical axis represents the sound pressure level, and the horizontal axis represents the frequency. The frequency is shown for a frequency band up to 10 kHz. The frequency characteristics of music vary greatly depending on the music category. For example, in rock and pops, the sound pressure level is relatively large in the band A of 80 to 200 Hz and the band C of 2 to 10 kHz, and the sound pressure level is relatively small in the band B of 300 Hz to 1 kHz. (FIG. 7A). In addition, a classic or the like often has an average sound pressure level for the entire band (FIG. 7B). Furthermore, in categories such as jazz, vocals, and talk, the sound pressure level is relatively small for band A and band C, and the sound pressure level is relatively large in band B (FIG. 7C).

  Returning to FIG. 6, when each frequency characteristic is specified, the CPU 111 controls the difference calculation unit 230 to calculate the difference (step B <b> 12). For example, the difference in sound pressure level is calculated for each frequency in the frequency band shown in FIG. When the difference is calculated, the CPU 111 instructs the audio signal generation unit 150 to generate an audio signal of the adjustment sound based on the difference. Based on such an instruction, the audio signal generation unit 150 generates an audio signal of the adjustment sound (step B13).

  Here, with reference to FIG. 7 again, the adjustment sound according to the present embodiment will be described. The adjustment sound in the present embodiment refers to a sound that should be added to the engine sound in order to match the engine sound to the music basically like the first embodiment. Here, basically, it is preferable that the adjustment sound corresponding to each order of the engine sound is generated so that the difference between the frequency characteristic of the music and the frequency characteristic of the engine sound is reduced. For example, for a certain frequency, if the sound pressure level in the frequency characteristic of the music is higher, the adjustment sound that increases the engine sound of the order corresponding to that frequency is also the sound pressure level in the frequency characteristic of the music. If is small, it is preferable to generate an adjustment sound that attenuates the engine sound of the order corresponding to the frequency. For example, if the frequency characteristics of the music are as shown in FIG. 7A, the engine sound of the second order (100 Hz) and the fourth order (200 Hz) are adjusted if the engine speed is 3000 rpm. Thus, the frequency characteristic of the engine sound can be approximated to that of the music.

  Further, even if the absolute value of the difference is relatively large, for example, in FIG. 7A, the sound pressure level of the engine sound is higher at the frequency corresponding to the band A and the band C, and the engine at the frequency corresponding to the band C. If the sound pressure level of the sound is smaller, the frequency characteristic of the engine sound is generally similar to the frequency characteristic of the music shown in FIG. In such a case, the adjustment sound need not be positively applied.

  Furthermore, from the viewpoint of approximating the frequency characteristics of engine sound to that of music, in addition to realizing such approximation by emphasizing engine sound of a certain order, it is relatively possible to attenuate engine sound other than that order. A subtraction principle that performs such approximation can also be employed.

  Therefore, the CPU 111 can relatively freely determine the frequency and sound pressure level of the adjustment sound as long as the frequency characteristics of the music and the engine frequency characteristics are similar. In the process according to step B13 in FIG. 6, the CPU 111 controls the audio signal generation unit 150 so that the optimum adjustment sound is generated based on the comparison of the frequency characteristics.

  Returning to FIG. 6, when the audio signal is generated, the adjustment sound is emitted from the speaker 15 (step A16), and the engine sound is naturally matched with the frequency characteristics of the music by the interaction between the adjustment sound and the engine sound. It will be a thing. When the adjustment sound is emitted, the process returns to step A10, and the above-described series of processes is looped as long as the music is being emitted.

  Thus, according to the engine sound control apparatus 200 according to the second embodiment, the engine sound is increased or decreased with respect to the frequency corresponding to each order of the engine sound according to the frequency characteristics of the music, or By maintaining the engine sound, the engine sound can be adjusted to a sound that matches the frequency characteristics of the music. In other words, it is possible to supply engine sound that is comfortable for the occupant to the passenger compartment in a relatively simple manner.

<Third Embodiment>
The sound in the passenger compartment is not limited to the music emitted from the audio device as in the first and second embodiments described above. Here, a third embodiment of the present invention based on such a purpose will be described.

  First, the configuration of the third embodiment of the present invention will be described with reference to FIG. FIG. 8 is a block diagram of the engine sound control system 30 according to the third embodiment of the present invention. In the figure, the same parts as those in FIGS. 1 and 2 are denoted by the same reference numerals, and the description thereof is omitted.

  In FIG. 8, the engine sound control system 30 is different from the engine sound control system 100 in that an engine sound control device 300 is provided instead of the engine sound control device 100.

  The engine sound control apparatus 300 includes a control unit 110, a frequency characteristic specifying unit 310, a moving average calculation unit 320, a difference calculation unit 230, and an audio signal generation unit 150.

  The control unit 110 is similar to the first embodiment in terms of hardware, and the engine sound control process executed by the CPU 111 is different from the first embodiment.

  The frequency characteristic specifying unit 310 is configured to be able to specify the frequency characteristic of the engine sound in the vehicle interior from the engine sound in the vehicle interior collected by the microphone 13, and the second frequency according to the second embodiment. The characteristic specifying unit 220 and the hardware configuration are the same.

  The moving average calculation unit 320 is configured to be able to calculate a moving average related to the frequency characteristic of the engine sound specified by the frequency characteristic specifying unit 310. This moving average is used as a target sound in the passenger compartment.

  With this configuration, the engine sound control device 300 causes the engine sound to match the moving average of the engine sound in the passenger compartment by the CPU 111 executing the engine sound control process. Here, with reference to FIG. 9, the details of the engine sound control process will be described as the operation of the engine sound control apparatus 300. FIG. 9 is a flowchart of the engine sound control process. In FIG. 9, the same parts as those in FIGS. 2 and 6 are denoted by the same reference numerals, and the description thereof is omitted.

  In FIG. 9, when the frequency characteristic of the engine sound is specified (step B11), the CPU 111 determines whether or not the moving average of the frequency characteristic has already been calculated (step C10). Here, the moving average of the frequency characteristics is an average characteristic obtained by averaging the frequency characteristics of the engine sound over approximately several seconds, and is a target value of the sound in the passenger compartment. That is, the engine sound control device 300 controls the engine sound so that the engine sound always follows the moving average.

  For example, the moving average is calculated for each engine speed during the first driving of the vehicle, and stored in the RAM 113 of the control unit 110 for each engine speed. This moving average is used, for example, as a target value of the sound in the passenger compartment until the engine battery is replaced.

  Therefore, the process according to step C10 is a process of determining whether or not the moving average corresponding to the current engine speed is stored in the RAM 113. When the moving average is not stored (step C10: NO), the CPU 111 instructs the moving average calculation unit 320 to calculate the moving average. Based on such an instruction, the moving average calculation unit 320 calculates the moving average (step C11) and stores it in the RAM 113.

  On the other hand, when the moving average has already been calculated (step C10: YES), the CPU 111 instructs the difference calculation unit 230 to calculate the difference between the current frequency characteristic and the moving average. Based on the instruction, the difference calculation unit 230 calculates the difference (step C12). This difference is output, for example, as a difference in sound pressure level for each engine sound frequency.

  When the difference is calculated, the CPU 111 instructs the audio signal generation unit 150 to generate an audio signal related to the adjustment sound based on the difference, and the audio signal generation unit 150 generates the audio signal of the adjustment sound according to the instruction. To do.

  Here, the adjustment sound according to the present embodiment is a sound to be added to the engine sound in order to match the frequency characteristic of the engine sound at the present time to the moving average, and the sound pressure level for each frequency of the engine sound. The sound is emitted according to the difference between the two.

  Therefore, in the engine sound, the CPU 111 has a sound whose sound pressure is insufficient with respect to the moving average so that the adjustment sound is in phase with the engine sound, and the sound pressure is excessive with respect to the moving average. For the frequencies, the sound signals are generated so as to be the adjustment sounds having the phase reversed from that of the engine sound.

  When the audio signal related to the adjustment sound is generated, the adjustment sound is emitted into the vehicle interior via the amplifier 14 and the speaker 15 (step A16). When the adjustment sound is emitted, the process returns to step B11 again, and a series of processes is repeated. As a result, the sound in the passenger compartment constantly follows the moving average. That is, the sound in the passenger compartment is always equal for each engine speed by absorbing the variation in engine sound. Therefore, the engine speed and the sound in the vehicle compartment always have a linear relationship, and it is possible to supply engine sound that is comfortable for the occupant to the vehicle interior.

  If the engine does not change significantly, the moving average may not be updated semipermanently. However, since the engine deteriorates over time, the moving average itself may not be suitable as the target value of the sound in the passenger compartment. obtain. Therefore, the CPU 111 constantly calculates the moving average by controlling the moving average calculator 320 in the process of repeating the above processing. When the moving average is different from the moving average stored in the RAM 113 as a sound pressure level by a predetermined value, for example, 5 dB or more, the CPU 111 updates the moving average at the corresponding engine speed in the RAM 113. In this way, the moving average of sound in the passenger compartment is always kept optimal.

  The present invention is not limited to the above-described embodiments, and can be appropriately changed without departing from the gist or concept of the invention that can be read from the claims and the entire specification. Is also included in the technical scope of the present invention.

1 is a block diagram of an engine sound control system according to a first embodiment of the present invention. It is a flowchart of the engine sound control process which an engine sound control apparatus performs in the system of FIG. FIG. 3 is a table illustrating the correspondence between music features and engine sound orders in the process of FIG. 2. FIG. It is a schematic diagram for demonstrating the order of an engine sound in connection with the process of FIG. It is a block diagram of the engine sound control system which concerns on 2nd Embodiment of this invention. It is a flowchart of the engine sound control process which an engine sound control apparatus performs in the system of FIG. FIG. 7 is a schematic diagram of frequency characteristics of music in the process of FIG. 6. It is a block diagram of the engine sound control system which concerns on 3rd Embodiment of this invention. It is a flowchart of the engine sound control process which an engine sound control apparatus performs in the system of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Engine sound control system, 11 ... Audio apparatus, 12 ... Pulse detection part, 13 ... Microphone, 14 ... Amplifier, 15 ... Speaker, 20 ... Engine sound control system, 30 ... Engine sound control system, 100 ... Engine sound control apparatus , 110 ... control unit, 120 ... tempo detection unit, 130 ... beat amount detection unit, 140 ... sound pressure level detection unit, 150 ... sound signal generation unit, 200 ... engine sound control device, 210 ... first frequency characteristic specifying unit, 220 ... second frequency characteristic specifying unit, 300 ... engine sound control device, 310 ... frequency characteristic specifying unit, 320 ... moving average calculating unit.

Claims (9)

In a vehicle including an audio device, an engine sound control device for controlling engine sound in a vehicle interior of the vehicle,
Feature identifying means for identifying the characteristics of the music emitted into the vehicle interior as the output of the audio device from the sound emitting means provided in the audio device;
An audio signal generating means for generating an audio signal having a frequency corresponding to the specified characteristic in the frequency band of the engine sound based on the specified characteristic;
Controlling at least one of sound emitting means provided separately from the audio device and sound emitting means provided in the audio device so that sound corresponding to the generated sound signal is emitted into the vehicle interior And an engine sound control device. Sound collecting means for collecting engine sound in the vehicle interior;
The engine sound control apparatus according to claim 1, wherein the sound signal generation unit generates the sound signal based on the collected engine sound. The music further comprises a music feature amount acquisition means for acquiring a music feature amount quantified for each predetermined feature item,
The engine sound control apparatus according to claim 1, wherein the feature specifying unit specifies the feature of the music based on the music feature amount. The engine sound control apparatus according to claim 3, wherein the characteristic item includes at least one of a tempo and a beat in the music. The frequency corresponding to the specified feature is the specified feature among the orders of the engine sound set in advance for each feature of the music as defining the frequency of the engine sound to be emphasized or attenuated. The engine sound adjusting device according to any one of claims 1 to 4, wherein the engine sound adjusting device has a frequency corresponding to a corresponding order. In a vehicle including an audio device, an engine sound control device for controlling engine sound in a vehicle interior of the vehicle,
First frequency characteristic specifying means for specifying a frequency characteristic of music to be emitted into the vehicle interior as an output of the audio device from sound emitting means provided in the audio device;
An audio signal generating means for generating an audio signal having a frequency to be adjusted out of the frequency band of the engine sound based on the frequency characteristics of the specified music;
Controlling at least one of sound emitting means provided separately from the audio device and sound emitting means provided in the audio device so that sound corresponding to the generated sound signal is emitted into the vehicle interior And an engine sound control device. A second frequency characteristic specifying means for specifying a frequency characteristic of the engine sound;
The engine according to claim 6, wherein the sound signal generating unit generates the sound signal based on a mutual comparison between a frequency characteristic of the identified music and a frequency characteristic of the identified engine sound. Sound control device. The engine sound control device according to any one of claims 6 and 7, wherein the frequency to be adjusted includes a frequency corresponding to an order of the engine sound. An engine sound control device for controlling engine sound in a vehicle cabin,
A frequency characteristic specifying means for specifying a frequency characteristic of the engine sound;
Moving average calculating means for calculating a moving average of the identified frequency characteristics;
An audio signal generating means for generating an audio signal having a frequency to be adjusted in the frequency band of the engine sound, based on a difference between the moving average and the specified frequency characteristic;
An engine sound control apparatus comprising: control means for controlling predetermined sound emission means so that sound corresponding to the generated sound signal is emitted into the vehicle interior.

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