JPH03281976A - Control device for sound from engine and its device - Google Patents

Abstract

PURPOSE:To emphasize good feeling sound by selecting different phase difference in a phase difference imparting process, and thereby freely selecting attenuating or emphasizing engine generating sound in a control device for engine generating sound including the phase difference imparting process which changes the phase of an electric signal due to an oscillation of air passing through an engine. CONSTITUTION:A phase control circuit 20 is provided, which inputs the detected signal V1 of a revolution detecting sensor 10, and the noise signal V4 of a noise sensor 11 such as a microphone and the like disposed on an inlet air duct 7. In addition, change- over switches 4 and 5 for a first mode and a second mode are disposed on an instrument 3 within a cabin, and respective input signals V2 and V3 are also inputted into the phase control circuit 20. And when change-over to the first mode is made, high frequency components included in noise signals are removed, only band frequencies other than high frequencies are allowed to pass through being reversed in phase, signals to which phase difference is imparted, are forwarded to the inside of an air cleaner by means of a speaker, and let them interfere with generated sound so that they are thereby attenuated. On the other hand, when change-over to the second mode is made, noise signals of specific frequencies included in the band frequencies are processed in such a way as to be left within the cabin as good feeling music sound.

Description

[Detailed Description of the Invention] 1 Yutaka Kojo ■ 1 minute update The present invention relates to a technology that can reduce the noise generated by an engine of an automobile, etc., and in particular, an engine generator that can provide a quiet space in the vehicle interior or emphasize a pleasant sound with a feeling of sports driving. This invention relates to sound control methods and devices.

Previously, there have been various types of silencers that reduce noise generated by engines, and noise detection sensors such as microphones are used to detect sound inside the intake pipe on the upstream and downstream sides of the air cleaner installed in the engine intake pipe. A system is known in which the noise is detected and the noise signal is offset and reduced by giving a phase difference to the noise signal using an interference wave.

The issue that Akira is trying to solve is that these noise reduction systems are insufficient to provide a suitable driving sensation for the driver and other occupants while the vehicle is running, and that there is little room for occupants to make choices regarding noise. There wasn't.

SUMMARY OF THE INVENTION An object of the present invention is to provide a silencing control method and apparatus for engine-generated noise that can arbitrarily select to emphasize or attenuate the pleasurable sound frequency among engine noise components by phase inversion.

The method for controlling engine noise according to the present invention involves a vibration detection process that converts the vibration of air passing through the engine into an electrical signal as a noise signal while the engine is running, and a phase change of the obtained electrical signal. The method includes a step of imparting a phase difference, which changes the phase, and a mixing step, which causes the sound waves of the loudspeaker driven by the phase-changed signal to interfere with the sound waves in the air. Attenuation and enhancement of the engine-generated sound can be selected by selecting different phase differences in the phase difference imparting process. It is also possible to perform filtering to remove signals of a specific frequency from the converted electrical signal.

In addition, in the embodiment of the present invention, the phase difference of the obtained electric signal is changed by a phase difference corresponding to the engine rotation speed in the step of providing one phase difference, which includes a step of detecting the rotation speed of the engine. By selecting different phase differences during the application process, it is possible to select attenuation or enhancement of the engine-generated sound.

The engine noise control device according to the present invention includes a noise sensor that converts the vibration of air passing through the engine into an electrical signal as a noise signal while the engine is operating, and an electrical signal output from the noise sensor based on the output of an input discrimination circuit. It has a phase difference applying means that changes the phase of a signal, and a loudspeaker that is driven by the output of the phase difference applying means and generates a sound wave that interferes with the sound wave in the air. Depending on the output of the mode selector switch, the input discrimination circuit generates different outputs, and it is possible to select whether to attenuate or emphasize the sound generated by the engine. Furthermore, a filter is provided to remove signals of specific frequencies from the converted electrical signals. Filters include bandpass filters and programmable filters, and include filters that remove signals at specific frequencies from electrical signals.

In the embodiment of the present invention, a rotation speed detection means for detecting the engine rotation speed, a mode changeover switch, an input discrimination circuit that generates different outputs depending on the output of the mode changeover switch, and a phase difference corresponding to the engine rotation speed are provided. An inverting amplifier circuit is provided that changes the phase of the electrical signal obtained by the input discriminator circuit and selectively attenuates or enhances the engine noise based on the output of the input discrimination circuit. The filter circuit removes harmonic components contained in the noise signal and leaves or passes specific frequencies.

Operation 1: Converts air vibrations passing through the engine during engine operation into electrical signals as noise signals. Different phase differences are selected to vary the phase of the resulting electrical signal. The phase-changed signal drives a loudspeaker to cause sound waves in the loudspeaker to interfere with sound waves in the air. Thereby, it is possible to select whether to attenuate or emphasize the sound generated by the engine.

Furthermore, the engine rotation speed is detected, and the phase of the obtained electrical signal is changed with a phase difference corresponding to the engine rotation speed. In this manner, by selecting different phase differences, it is possible to select attenuation or enhancement of the engine generated sound.

The noise sensor converts air vibrations passing through the engine during operation of the engine into electrical signals as noise signals. The input discrimination circuit generates different outputs depending on the output of the mode changeover switch, and the phase difference applying means changes the phase of the electrical signal output from the noise sensor based on the output of the input discrimination circuit. The loudspeaker is driven by the output of the phase difference applying means and generates a sound wave that interferes with the sound wave in the air, so that attenuation or emphasis of the engine-generated sound can be selected. The filter removes signals of a specific frequency from the converted electrical signal. Filters include bandpass filters and programmable filters, and remove signals at specific frequencies from electrical signals.

In the embodiment of the present invention, a detection signal of the engine rotation speed is sent to the phase control circuit, and by arbitrarily selecting a mode changeover switch in the passenger compartment, a signal for either the first mode or the second mode is sent to the phase control circuit. Sent.

Further, a noise signal caused by engine-generated sound detected between the engine and the air cleaner is sent to the filter circuit of the phase control circuit.

When switching to the first mode, the first filter of the filter circuit removes harmonic components included in the detected noise signal,
Pass only band frequencies other than harmonics. The band frequency that has passed through the first filter is sent out from the second filter as it is. The phase of the transmitted band frequency signal is inverted by an inverting amplifier circuit, and the phase-differenced signal is sent through a loudspeaker into the air cleaner, where it interferes with the generated sound passing through the air cleaner and is attenuated. That is, the detected noise signal is substantially muted, and the interior of the vehicle is maintained as a quiet space.

Furthermore, by switching to the second mode, the first filter of the filter circuit removes harmonic components contained in the detected noise signal and passes only the band frequency. At this time, the second filter is activated by an activation signal from the input discrimination circuit, which is controlled based on the engine rotation signal and the second mode signal.

That is, the second filter leaves a noise signal of a specific frequency included in the frequency band passed through the first filter in the vehicle interior as a favorable musical tone. Further, frequencies of components other than the specific frequency are sent out from the second filter. The phase of this transmitted band frequency signal is inverted by the inverting amplifier circuit of the phase control circuit.

A signal with a phase difference is sent through a loudspeaker into the air cleaner,
It is emphasized by interfering with the generated sound passing through the air cleaner.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a method and apparatus for controlling engine noise according to the present invention will be described with reference to the drawings. The subject here is the control of engine-generated noise in the intake duct of an automobile engine.

In FIGS. 1 and 2, the required configuration of the control device 1 according to the present invention is as follows.

■ A rotation speed detection sensor 10 that is a means for detecting the rotation speed N (rpm) of the engine 2; ■ A first mode changeover switch 4 disposed in the vehicle interior instrument 3 to actively make the vehicle interior a quiet space; A second mode selector switch 5 which obtains a sports driving sensation by extracting a signal of a specific frequency from the engine noise and controlling it to a favorable sound; Noise sensor 11゜ which is a means for detecting noise ■ A detection signal v1 is sent to the rotation speed detection sensor 1o, and each input signal V2 of the first mode and second mode is input by turning on the changeover switch 4.5. Input discrimination circuit 3 that performs control based on v□
o, and a filter circuit 40 that removes harmonic components included in the detection signal v4 from the noise sensor 11 and leaves or passes a specific frequency, and an inverting amplifier circuit that inverts the phase of the signal passed through the filter circuit 4o. A phase control circuit 20゜ equipped with 5o is also installed inside the air cleaner 6 and generates a signal sent from the inverting amplifier circuit 5o to interfere with and attenuate the generated sound passing through the air cleaner 6. It consists of a loudspeaker 8 and the like.

Specifically, a rotation speed detection sensor 10 that detects the rotation speed N (rpm) of the engine 2 is arranged, and this detection signal v1 is sent to a phase control circuit 20 by a microcomputer.
will be sent to. In addition, an air cleaner 6 is installed in the intake duct 7.
is arranged, and the engine 2 is installed on the upstream side of this air cleaner 6.
A noise sensor 11 such as a microphone is disposed in the intake duct 7 between the two. The signal v4 of the noise generated by the engine 2 detected by the noise sensor 11 is also sent to the phase control circuit 20.
will be sent to.

Further, the vehicle interior instrument 3 is provided with a first mode changeover switch 4.5 and a second mode changeover switch 4.5, which are operated directly by the driver or by another passenger. That is, the input signal v by turning on the arbitrarily selected changeover switch 4.5,
, v, are sent to the phase control circuit 20.

Here, in the configuration of the phase control circuit 20 shown in FIG. 2, the main body 30 of the microcomputer is a CPU (central processing unit).
31, memory 32 that stores in advance a phase difference signal corresponding to the engine rotation speed, l10 (input/output) boat 33 and D
/A converter 34, and these are connected by a data bus 35 and an address bus 36. The detection signal v1 from the rotational speed detection sensor 10 mentioned above and the input signals V2 and V1 input by arbitrarily selecting one of the first mode and second mode changeover switches 4.5 are input to the I10 port 33. It is input to the CPU 31 from the input port. These input signals V1. V4 is stored in memory 32.

Further, the phase control circuit 20 is provided with a filter circuit 4°. In general, a filter circuit is a circuit that has the property of blocking alternating current at a certain frequency or frequency range, or on the contrary, selectively passing it through.It is usually a filter using a combination of a coil or a resistor and a capacitor. be. Depending on their characteristics, they are classified into low-pass (pass) filters, high-pass (pass) filters, band (pass-band-pass) filters, and band-elimination filters.

A signal V4 detected by the noise sensor 11 is input to the filter circuit 40. The filter circuit 40 includes a first filter 41 and a second filter 42 as band-pass filters, and the noise signal V is first input to the first filter 41. This first filter 41 cuts unpleasant sounds called harmonics among the frequencies of the noise signal v4, and passes band frequencies. Further, the second filter 42 leaves a specific frequency out of the band frequencies passed by the first filter 41, and sends out the other frequency signal v4.

The second filter 42 is the I10 port 3 of the input discrimination circuit 30.
It is connected to the output port of No. 3, and is actuated by an activation signal from there to send out a signal v4. The signal V sent out from this second filter 42 is sent to the next inverting amplifier circuit 50.

That is, the 1-phase control circuit 20 has an inverting amplifier circuit 50, which includes a first amplifier 51 and a delay circuit 52 connected to the D/A converter 34 of the input discrimination circuit 30, and a filter circuit. It has a second amplifier 53 connected to the second filter 42 of 4o. The second amplifier 53 constitutes a phase difference imparting means for inverting the phase of the signal v4 sent out from the second filter 42. The first amplifier 51 is connected to a loudspeaker 8 within the air cleaner 6.

Next, the operation and effect of the embodiment will be explained.

As the engine 2 operates, the frequency of engine-generated noise changes in the intake duct 7 over a wide operating range from low speed to high speed.

The rotation speed N (rpm) of the engine 2 is sequentially detected by the rotation speed detection sensor 10, and this rotation signal V1 is sent to the input discrimination circuit 30 of the phase control circuit 20. The input discrimination circuit 30 selects phase difference data corresponding to the rotation signal v1 from the memory 32. The phase difference data in the memory 32 is sent to the delay circuit 52.

Based on the phase difference data, the delay circuit 52 can shift the phase by a desired amount of time suitable for attenuating or emphasizing engine noise. At this time, a noise signal v4 generated by the engine 2 is detected by the noise sensor 11 in the intake duct 7, and this noise signal v4 is also sent to the phase control circuit 20.

On the other hand, while driving, depending on the arbitrary selection of one passenger,
The first mode can be set to reduce the noise generated by the engine to make the interior of the vehicle completely silent, or the second mode can be set to make use of the noise generated by the engine to create a sports driving sensation.

When the changeover switch 4 is turned on to set the first mode, the first mode changeover signal v2 is sent to the phase control circuit 20. That is, in the phase control circuit 2°, along with this first mode switching signal v2, the rotation signal V and the noise signal v
Control based on 4 is performed. During this time, I10 port 3
3, control signals v2 and 3 are also sent to the first amplifier 51 and delay circuit 52 of the inverting amplifier circuit 5o.

The noise signal v4 is first input to the first filter 41 of the filter circuit. Here, unpleasant sounds called harmonics in the frequency components of the noise signal V are cut. The band frequency, which is another component of the noise signal v4, is passed through the first filter 41 as it is.
pass through. At this time.

The second filter 42 is not activated. Therefore, the band frequency passed through the first filter 41 also passes through the second filter 42 as is. Filter signal (band frequency) sent out from the second filter 42 ■4 is the next inverting amplifier circuit 5
The phase is inverted by the second amplifier 53 of 0. The phase of the phase-inverted filter signal is shifted by a delay circuit 52, etc.
After being amplified again by the first amplifier 51, it is sent to the loudspeaker 8.

The sound emitted from the loudspeaker 8 interferes with the generated sound passing through the air cleaner 6 to reduce attenuation. This makes it possible to create a quiet space in the vehicle interior with almost all noise being muted.

Further, when the changeover switch 5 is turned on to set the second mode, the second mode changeover signal V3 is output to the phase control circuit 2.
Sent to 0. That is, in the phase control circuit 20, control is performed based on the rotation signal V and the noise signal V as well as the second mode switching signal V. Input discrimination circuit 30
A control signal v1 is output from the I10 port 33 of the control signal V1, and is sent to the second filter 42 of the filter circuit 40 as an actuation signal ■. During this time, the control signals v2 and 3 are also sent from the I10 port 33 to the first amplifier 51 and delay circuit 52 of the amplifier circuit 50.

The noise signal v4 is first input to the first filter 41 of the filter circuit. Here, unpleasant sounds called harmonics in the frequency components of the noise signal v4 are cut. The band frequency, which is another component of the noise signal v4, is passed through the first filter 41 as it is.
pass through. At this time, the second filter 42 is activated by a control signal from the input discrimination circuit 3o. First filter 41
The second filter 42 leaves only the specific frequency component of the band frequencies passed through. The signal with this specific frequency is a component of the initial noise signal v4 that becomes a musical tone with a pleasant sensation. Signals with components other than the specific frequency are sent out from the second filter 42 as a filter signal V. The phase of the filter signal v4 is inverted by the second amplifier 53 of the next inverting amplifier circuit 50. The phase of the phase-inverted filter signal is shifted in the delay circuit 52, and after being amplified again in the first amplifier 51, it is sent to the loudspeaker 8. The sound from the loudspeaker 8 interferes with the generated sound passing through the air cleaner 6 to emphasize musical sounds and attenuate and reduce unpleasant sounds.

In this manner, in the second mode, the second filter 42 extracts only the favorable musical tone component from the noise signal v4 to obtain a sports feeling while driving. In addition, noise components other than musical tones are passed through an air cleaner 6 through a loudspeaker 8 after being given a phase difference.
By flowing inside the air cleaner 6, it is possible to interfere with the generated sound passing through the air cleaner 6, reduce unpleasant sounds by attenuation, and emphasize musical sounds.

As explained above, in the present invention, by switching to the first mode, most of the engine noise generated during driving can be silenced, and a quiet interior space can be obtained. Also, the second
When switching to this mode, only the pleasant musical tones contained in the noise are extracted, giving a comfortable sports sensation while driving.

[Brief explanation of drawings]

1 and 2 are a layout diagram of a control device for engine generated noise and a block diagram of a phase control circuit according to the present invention. 2. Engine, 4.5. First mode and second mode selector switch, 6. Air cleaner, 7 Intake duct,
8. Loudspeaker, 10. Rotation speed detection sensor (engine rotation speed detection means), 11.. Noise sensor (noise detection means)
, 20... Phase control circuit, 30... Input discrimination circuit, 40
...filter circuit, 41..first filter, 42..second filter, 50..inverting amplifier circuit.

Claims (9)

[Claims] (1) A vibration detection process that converts air vibrations passing through the engine into electrical signals as noise signals during engine operation, a phase difference imparting process that changes the phase of the obtained electrical signal, and a signal with a changed phase. A method for controlling engine sound that includes a mixing process in which sound waves from a loudspeaker driven by a loudspeaker interfere with sound waves in the air, in which different phase differences are selected in the phase difference imparting process to attenuate and emphasize the engine sound. A method for controlling engine noise, which is characterized by being selectable. (2) The method for controlling engine noise according to claim (1), further comprising a filtering process for removing a signal of a specific frequency from the converted electrical signal. (3) A vibration detection process that converts air vibrations passing through the engine during engine operation into electrical signals as noise signals, a phase difference imparting process that changes the phase of the obtained electrical signal, and a signal with a changed phase. A method for controlling engine sound that includes a mixing process in which sound waves from a loudspeaker driven by Control of engine noise, characterized in that it is possible to change the phase of the obtained electrical signal with a phase difference corresponding to the phase difference, and select a different phase difference in the phase difference imparting process to select attenuation or emphasis of the engine noise. Law. (4) A noise sensor that converts air vibrations passing through the engine into an electrical signal during engine operation, and a phase difference that changes the phase of the electrical signal output from the noise sensor based on the output of the input discrimination circuit. In a control device for engine-generated sound, which includes a applying means and a loudspeaker that is driven by the output of the phase difference applying means and generates a sound wave that interferes with the sound wave in the air, the input discriminating circuit changes depending on the output of the mode changeover switch. A control device for engine-generated sound, characterized in that it can generate output and select attenuation or emphasis of the engine-generated sound. (5) The engine-generated sound control device according to claim (4), further comprising a filter that removes a signal of a specific frequency from the converted electrical signal. (6) The engine-generated sound control device according to (5), wherein the filter includes a bandpass filter and a programmable filter, and includes a filter that removes a signal of a specific frequency from the electrical signal. (7) A noise sensor that converts the vibration of air passing through the engine into an electrical signal as a noise signal during operation of the engine, a phase difference applying means that changes the phase of the electrical signal output from the noise sensor, and a phase difference applying means A control device for engine-generated sound comprising a loudspeaker driven by the output of the engine and generating a sound wave that interferes with the sound wave in the air, comprising: a rotation speed detection means for detecting the rotation speed of the engine; a mode changeover switch; The input discrimination circuit generates different outputs depending on the output of the changeover switch, and the phase of the electrical signal obtained by changing the phase difference corresponding to the engine rotation speed is changed, and the output of the input discrimination circuit selectively changes the engine noise. 1. A control device for engine-generated noise, comprising an inverting amplification circuit that attenuates or enhances the noise. (8) The engine-generated sound control device according to claim (7), further comprising a filter circuit that removes harmonic components contained in the noise signal and leaves or passes a specific frequency. (9) A noise sensor that converts the vibration of air passing through the engine into an electrical signal as a noise signal during operation of the engine, a phase difference imparting means that changes the phase of the electrical signal output from the noise sensor, and a phase difference imparting means A loudspeaker that is driven by the output of a noise signal and generates a sound wave that interferes with the sound wave in the air. A filter circuit having a programmable filter that waves, a rotation speed detection means for detecting the engine rotation speed, a mode changeover switch that selects a specific frequency of the programmable filter, and an input discrimination circuit that generates different outputs depending on the output of the mode changeover switch. and an inverting amplifier circuit that changes the phase of the electrical signal obtained by a phase difference corresponding to the engine rotational speed, and selectively attenuates or enhances the engine-generated sound using the output of the input discrimination circuit. Features a control device for engine noise.