Engine Sound Processing System

• US 20080192954A1
• Filed: 03/10/2006
• Published: 08/14/2008
• Est. Priority Date: 03/11/2005
• Status: Active Grant

• Current Assignee: Yamaha Corporation
• Original Assignee: Yamaha Corporation
• Inventors: Yoshioka, Yasuo, Honji, Yoshikazu, Takahashi, Akio, Kobayashi, Tetsu
• Granted Patent: US 8,155,343 B2
• Time in Patent Office: Days
• US Class Current: 381/86
• CPC Class Codes: G10K 15/04 Sound-producing devices G10K15/02 takes precedence

Abstract

Microphones are provided at an air inlet of the engine and a vehicle-cabin-side wall surface of an engine room, and engine sounds are picked up. The engine sound is processed by a signal processing section, and the processed engine sound is output from a speaker provided in a vehicle cabin. The signal processing section is provided with a filter which simulates a sound insulation characteristic of the vehicle cabin and a transformation section for processing the engine sound according to driving condition. A spectrum transformation characteristic of the transformation section is determined according to values detected by a vehicle speed sensor, an engine speed sensor, and an accelerator depression sensor, and a spectrum of the engine sound is transformed by means of specification of the spectrum transformation characteristic, thereby enhancing an engine sound.

Claims

1. An engine sound processing system comprising:

a microphone which is disposed outside a vehicle cabin of an automobile and which picks up an engine sound of the automobile;

a sensor for detecting driving condition of the automobile;

a signal processing section which processes the engine sound picked up by the microphone in accordance with the detected result by the sensor and outputs the engine sound; and

a speaker for outputting the engine sound subjected to signal processing performed by the signal processing section.

2. The engine sound processing system according to claim 1, wherein the signal processing section includes a filter which exhibits a sound-insulation characteristic for simulating a sound insulation characteristic of a wall surface of the vehicle cabin and an active filter whose characteristic varies according to the driving condition.

3. The engine sound processing system according to claim 1, wherein the microphone is provided in numbers and disposed in one of or some of an air inlet and an air outlet of the engine, an engine head, and a wall surface of an engine room.

4. The engine sound processing system according to claim 1, wherein the sensor corresponds to one of a sensor for detecting an engine speed, a sensor for detecting a degree of depression of an accelerator, and a sensor for detecting speed of the automobile, or all of them.

5. The engine sound processing system according to claim 1 further comprising a control section which determines a signal processing characteristic according to the detected result by the sensor and which controls the signal processing section.

6. The engine sound processing system according to claim 5, wherein the control section includes a parameter table storing a relationship between the detected result by the sensor and the signal processing characteristic.

7. The engine sound processing system according to claim 5 further comprising an operation section which is connected to the control section and which enables a user to operate the signal processing characteristic of the control section.

8. The engine sound processing system according to claim 5 further comprising frequency analysis means for analyzing a frequency of engine sound picked up by the microphones, to determine a spectrum, wherein the signal processing section processes the spectrum determined by the frequency analysis means and sends an output to the speaker.

9. The engine sound processing system according to claim 8, wherein the control section enhances a peak of the spectrum determined by the frequency analysis means.

10. The engine sound processing system according to claim 8, wherein the control section increases a level of a valley between peaks of the spectrum determined by the frequency analysis means.

11. The engine sound processing system according to claim 5 further comprising:

frequency analysis means for analyzing a frequency of the engine sound picked up by the microphone and detecting a peak of the spectrum, wherein the signal processing section pitch-shifts the peak of the spectrum determined by the frequency analysis means, to enhance and output a specific frequency component; and

wherein the control section sets a frequency to be pitch-shifted by the signal processing section.

12. The engine sound processing system according to claim 5, further comprising:

a waveform generation section for generating a modulated signal waveform,

wherein the signal processing section outputs the modulated signal waveform generated by the waveform generation section to the speaker.

13. The engine sound processing system according to claim 12, wherein the control section sets a modulation period according to the detected result by the sensor.

14. The engine sound processing system according to claim 12, wherein the control section sets a depth of modulation according to the detected result by the sensor.

15. The engine sound processing system according to claim 12, wherein

the waveform generation section generates modulated signal waveforms corresponding to respective engine sounds picked up by the microphones;

and

the control section sets modulation periods of the modulated signal waveforms at periods synchronized with the respective engine sounds picked up by the microphones.

16. The engine sound processing system according to claim 15, wherein the control section outputs peaks of the modulated signal waveform at the same timing as that of respective peaks of the picked-up engine sound.

17. The engine sound processing system according to claim 5 further comprising chord construction means for, when chord construction information is given, generating an audio consonant signal having a pitch in consonance with a pitch of the engine sounds picked up by the microphones, in accordance with the chord construction information and adding the audio signal of consonance to the engine sound and outputs the added engine sound.

18. The engine sound processing system according to claim 17, wherein the control means generates chord construction information according to the detected result by the sensor and provides the chord construction information to the chord construction means.

19. The engine sound processing system according to claim 17, wherein the control section specifies the driving condition according to a current value of the detected result by the sensor or a manner of change in a signal output from the sensor within a given period of time in the past, and generates chord construction information according to the driving conditions.

20. The engine sound processing system according to claim 17, wherein the chord construction means includes a pitch transformation section which subjects the picked-up engine sounds to pitch transformation, to generate the audio signal of consonance.

21. The engine sound processing system according to claim 17, wherein the chord construction means includes a synthesis section which synthesizes an audio consonant signal having a target pitch by taking an ignition pulse for the engine of the vehicle as a trigger.

22. The engine sound processing system according to claim 1, wherein the signal processing section includes phase correction means which has a plurality of types of correction modes and which makes, according to the correction mode selected by the user, a correction conforming to a frequency to a phase characteristic of an engine sound supplied to the speaker.

23. The engine sound generation system according to claim 22 further comprising an engine speed sensor for measuring an engine speed of the vehicle, wherein the phase correction means determines, according to an engine speed measured by the engine speed sensor, a frequency whose phase characteristic is to be corrected.

24. The engine sound generation system according to claim 22 further comprising an accelerator depression sensor for measuring the degree of depression of an accelerator of the vehicle, wherein the phase correction means increases or decreases an amount of correction to the phase characteristic according to the degree of depression of an accelerator measured by the accelerator depression sensor.

25. The engine sound generation system according to claim 1, wherein the signal processing section adds distortion to the engine sound picked up by the microphone.

26. The engine sound processing system according to claim 25, wherein a degree of the distortion is dynamically changed according to at least either an engine speed or the degree of depression of an accelerator.

27. The engine sound processing system according to claim 25, wherein a type of the distortion to be added is dynamically changed according to at least either an engine speed or the degree of depression of an accelerator.

28. The engine sound processing system according to claim 25, wherein an equalizer section whose frequency characteristic is dynamically changed according to at least either an engine speed or the degree of depression of an accelerator is interposed between the microphones and the distortion section.

29. The engine sound processing system according to claim 25 further comprising an amplifier for outputting to the speaker the engine sound imparted with distortion at a sound volume which is dynamically controlled according to at least an engine speed or the degree of depression of an accelerator.

30. The engine sound processing system according to claim 25, wherein the distortion imparted by the signal processing section, the frequency characteristic of the filter, or the manner in which the sound volume of the amplifier is dynamically changed is changed according to a rate of change in engine speed or a rate of change in degree of depression of an accelerator.

31. A vehicle cabin acoustic controller comprising:

a speaker disposed in a vehicle cabin;

signal generation means for generating an audio signal representing a pseudo engine sound;

engine sound signal generation means for generating an engine sound signal from the audio signal and supplying the engine sound signal to the speaker, wherein the engine sound signal generation means generates an audio consonant signal having a pitch in consonance with a pitch of the audio signal according to the chord construction information when being provided with chord construction information and adds the audio consonant signal to the audio signal, to generate the engine sound signal; and

control means which monitors driving condition, generates chord construction information according to driving condition, and imparts the chord construction information to the chord construction means.

32. An engine sound generation system comprising:

a speaker disposed in a vehicle cabin; and

signal generation means for generating an engine sound signal representing a pseudo engine sound and supplying the engine sound signal to the speaker,

wherein the signal generation means includes phase correction means which has a plurality of types of correction modes and makes a correction conforming to a frequency to a phase characteristic of an engine sound supplied to the speaker according to the correction mode selected by a user.