JP3392149B2 - Vehicle noise control device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for controlling engine noise to be reduced in a vehicle cabin. 2. Description of the Related Art Conventionally, as a noise control device of this kind, there is a device disclosed in, for example, Japanese Patent Application Laid-Open No. H1-1501344. This is, for example, as shown in FIG.
M microphones 1, 1,... Arranged at predetermined positions in the vehicle interior 32 to be subjected to noise control and detecting sound, and arranged at predetermined positions in the vehicle interior 32 to emit sound into the vehicle interior 32 L to generate
, And the synthesized sound of the noise in the cabin 32 and the sound emitted from each speaker 2 is output to each microphone 1.
, And the microphone 1 outputs microphone signals e1 to eM. Speaker signal y output to each speaker 2
1 to yL are obtained by passing a signal called a reference signal x output from the reference signal output device 103 through the digital filters F1 to FL. [0005] Reference numeral 15 denotes the digital filters F1 to FL.
Are operated to output signals y1 to y to each speaker 2.
A speaker signal generation device comprising a CPU for generating L, wherein the adaptive algorithm unit 16 of the speaker signal generation device generates the digital signal so that the sum of squares of the synthesized sound signal detected by each microphone 1 is minimized. The parameters of the filters F1 to FL are automatically adjusted.
As an algorithm for this adjustment, Least Mean Squ
are method (= LMS) is performed, and by this adjustment, the output signals y1 to the speakers 2 are reduced so that the sound detected by each microphone 1 is reduced based on the reference signal x from the reference signal output device 103. Generate yL.
Note that the reference signal x is a digital filter. [0005] The signal is input to the adaptive algorithm unit 16 through the filter. [0007] This is a model of a transfer characteristic between the L-th speaker 2 and the M-th microphone 1. In the speaker signal generator 15, since the signal processing is performed by digital calculation, the A / D converter 7 is provided at the input stage of the reference signal x, and the linear amplifier is provided at the input stage of the microphone signals e1 to eM. , And A / D converters 18, 18,.
However, the output stages of the speaker signals y1 to yL have D / A
, And speaker amplifiers 20, 20,... Formed of linear amplifiers, respectively. The reference signal x output from the reference signal output device 103 is input to the speaker signal generation device 15.
The microphone signals e1 to eM, which are analog signals output from the respective microphones 1, are amplified by the microphone amplifiers 17, respectively, are digitally converted by the A / D converter 18, and are input to the speaker signal generator 15. Further, the digital signals output from the speaker signal generation device 15 are converted into analog speaker signals y1 to yL by the D / A converter 19, respectively, and then amplified by the speaker amplifier 20 to be output to each speaker 2. . The reference signal x is a signal obtained from a vehicle noise source such as engine noise and running noise, and has a high correlation with the noise. For example, in the case of engine noise, noise levels at frequencies twice (secondary sound) or four times (quaternary sound) the engine speed are particularly audible, and a sine wave signal of these frequencies is used as the reference signal x. Thus, the engine noise that changes according to the operating state of the engine is controlled. In this case, as shown in the figure, an ignition pulse signal of the vehicle engine is detected by the ignition pulse detector 4, the signal is shaped by the waveform shaper 105, the signal is converted into a digital signal, and the sine wave signal is converted by the reference signal generator 108. Is generated. Specifically, in obtaining a sine wave signal as the reference signal x, in the above-described conventional example, a method is used in which an ignition pulse signal of an engine is divided and then tracking is performed by a tracking filter to obtain the reference signal x. A method of measuring a pulse period and generating a sine wave reference signal x based on the pulse period is shown. However, the above-mentioned conventional method requires a special tracking filter and a counter for measuring an ignition pulse period, and the circuit configuration and arithmetic processing are complicated. There was a problem that it took time. SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and an object of the present invention is to improve the method of generating a sine wave signal as a reference signal when controlling engine noise so that the reference signal can be simplified. An object of the present invention is to enable quick generation by a circuit configuration and arithmetic processing. In order to achieve the above object, according to the present invention, a triangular wave signal is generated from an ignition pulse signal of an engine, and the triangular wave signal and the original ignition pulse signal are generated. A sawtooth signal is generated based on the signal, and a sine wave signal as a reference signal is generated based on the sawtooth signal. Specifically, according to the present invention, a vehicle interior sound detecting means for detecting a vehicle interior sound, a speaker for generating a sound in the vehicle interior, and a reference for outputting a reference signal related to engine vibration in the vehicle. A vehicle comprising: a signal output unit; and a speaker signal generation unit that generates an output signal to a speaker based on the reference signal from the reference signal output unit so as to reduce a sound detected by the vehicle interior sound detection unit. The premise is a noise control device. [0015] Then, the reference signal output means, an ignition pulse detection means for detecting an ignition pulse signal of the engine, this Igunissho
The ignition pulse signal detected by the pulse detection means is input to a waveform shaper to generate a square wave signal.
A triangular wave generating means for generating a triangular wave signal by integrating the rectangular wave signal of the above with an integrator, and a triangular wave signal generated by the triangular wave generating means is input to a divider, and a rectifier and
The amplitude of the triangular wave signal is calculated based on the average effective value that has passed through the smoothing circuit.
Adjust to a constant, adjust the amplitude of the adjusted triangular wave signal and
By multiplying the signal from the waveform shaper with a multiplier,
A sawtooth wave generating means for inverting the triangular wave signal with a rectangular wave signal to generate a sawtooth signal, and a sine wave signal as a reference signal based on the sawtooth signal generated by the sawtooth signal And a sinusoidal wave generating means. With the above arrangement, according to the present invention, the ignition pulse signal detected by the ignition pulse detecting means is input to the triangular wave generating means, and its waveform is shaped.
The square wave signal is generated by the integrator, and this square wave signal is
Triangular wave signal by integrating the Ru is generated. And this
The triangular wave signal is input to the divider of the sawtooth wave generating means,
Average effective through rectifier and smoothing circuit in divider of
The amplitude of the triangular wave signal is adjusted to a constant value based on the value.
Triangular wave signal with adjusted amplitude and signal from waveform shaper
Is multiplied by a multiplier, which results in a rectangular signal
The signal is inverted by the wave signal to generate a sawtooth signal. Since the sawtooth wave signal can be used as information indicating an angle that is an integral multiple of the engine rotation angle, a sine wave signal is generated as a reference signal in the sine wave generation means based on the sawtooth signal. Therefore, a sine wave signal can be obtained without using a conventional tracking filter or counter, and a reference signal required for controlling engine noise can be quickly generated with a simple circuit configuration and arithmetic processing. Embodiments of the present invention will be described below with reference to the drawings. Since the basic configuration of the vehicle noise control device according to this embodiment is the same as that of the conventional example, the same parts as those in FIG. 6 are denoted by the same reference numerals, and detailed description thereof will be omitted. That is, this control device controls the engine noise, which changes according to the operating state of the engine, as noise, and as shown in FIG. 2, M microphones 1, 1,.
, A plurality of L speakers 2, 2,..., A reference signal output device 3 for outputting a reference signal x related to vibration of an engine (not shown) in the vehicle, and a reference signal x from the reference signal output device 3. Based on
C for generating output signals y1 to yL to each speaker 2 so that the sound detected by each of the microphones 1, 1,.
And a speaker signal generation device 15 composed of a PU. FIG. 4 shows a specific example of the layout of each of the above devices in an automobile. Reference numeral 31 denotes a vehicle body, 32 denotes a vehicle room provided at the center of the vehicle body 31, and 33 to 36 denote doors for opening and closing the vehicle room 32. A pair of left and right front seats 3 are provided on the front side in the vehicle interior 32.
7, 38, and one rear seat 39 is provided on the rear side. Reference numeral 40 denotes a steering wheel. Right and left sides of the headrests 37a, 38a in the front seats 37, 38 (positions close to the ears of the occupants seated in the front seats 37, 38) and left and right headrests 39a, 39 of the rear seat 39.
are mounted on the left and right sides (positions close to the ears of the occupants seated on the left and right sides of the rear seat 39), respectively, and a total of four microphones 1, 1,.
By means of 1,..., The sound in the cabin 32 of the car is detected near the occupant's ear. There are five speakers 2 (in the case of L = 5) for generating a sound in the passenger compartment 32, and the left and right front doors 3 on the left and right center of the instrument panel at the front end of the passenger compartment 32.
3 and 34 are disposed on the left and right sides of the package tray at the rear end of the vehicle compartment 32, respectively, and these speakers 2, 2,... Are also used for audio. The controller 21 for controlling the audio output of the speakers 2, 2,...
It is located in the instrument panel in front. In the controller 21, the speaker signal generation device 1
, A reference signal output device 3, microphone amplifiers 17, 17,... For amplifying the microphone signals e1 to eM from the respective microphones 1, and A / D converters 18, 18, for digitally converting the signals e1 to eM. , And a D / A converter 1 for converting the reference signal x passed through the digital filters F1 to FL into analog speaker signals y1 to yL.
, And speaker amplifiers 20, 20,... For amplifying the signals y1 to yL and outputting the amplified signals to the respective speakers 2. In the controller 21, an operation switch 22 for switching the operation of the noise control system and the audio system by the speaker signal generation device 15 is arranged on the roof portion of the passenger compartment. As a feature of the present invention, the reference signal output device 3 is configured as shown in FIG.
That is, the reference signal output device 3 includes an ignition pulse detector 4 for detecting an ignition pulse signal of the engine, and the detector 4 is arranged in the engine room of the vehicle as shown in FIG. The output signal of the detector 4 is input to a waveform shaper 5, which generates a rectangular wave signal having a duty ratio of, for example, 50% from the ignition pulse signal. The rectangular wave signal from the waveform shaper 5 is input to an integrator 6, and the integrator 6 integrates the rectangular wave signal to generate a triangular wave signal. The triangular wave signal output from the integrator 6 is digitally converted by the A / D converter 7 and then input to the reference signal generator 8. The output signal of the waveform shaper 5 is also directly input to the reference signal generator 8. As shown in detail in FIG. 1, the reference signal generator 8 includes a rectifier 9 for rectifying the triangular wave signal, and a smoothing circuit 10 for smoothing a signal obtained by the rectifier 9. , 10 to calculate the average effective value of the signal. The output signal of the smoothing circuit 10 is input to a divider 11, which divides the triangular wave signal by its average effective value, thereby adjusting the amplitude of the triangular wave signal to be constant. By the waveform shaper 5 and the integrator 6
Thus, a triangular wave generation circuit 12 that generates a triangular wave signal from the ignition pulse signal detected by the ignition pulse detector 4 is configured. Further, the triangular wave signal output from the divider 11 and the signal from the waveform shaper 5 are combined with a multiplier 1
3 and are multiplied. The triangular wave signal is inverted by the rectangular wave signal to generate a sawtooth wave signal. Therefore, the rectifier 9, the smoothing circuit 10, the divider 11, and the multiplier 1
Reference numeral 3 denotes a sawtooth wave generating means for generating a sawtooth wave signal based on the triangular wave signal generated by the triangular wave generation circuit 12 and the ignition pulse signal detected by the ignition pulse detector 4. The output signal of the multiplier 13 is input to a sine wave generator 14, where a sine wave signal as a reference signal x is generated based on the sawtooth signal. Others are the same as the conventional example (see FIG. 6). Therefore, in the above embodiment, when the noise control system is operated by the operation switch 22, the reference signal x of the engine noise output from the reference signal output device 3 is output from the speaker signal generation device 1.
5 is input. Similarly, the microphone signals e1 to eM, which are analog signals output from the respective microphones 1, are respectively amplified by the microphone amplifiers 17, 17,.
The digital signals are converted by the A / D converters 18, 18,... And input to the speaker signal generator 15. Further, the digital signal generated by passing the reference signal x through the digital filters F1 to FL in the speaker signal generator 15 is converted into analog speaker signals y1 to yL by the D / A converters 19, 19,. The speaker signals y1 to yL are amplified by the speaker amplifiers 20, 20,. When the reference signal output device 3 generates the reference signal x, first, as shown in FIG. 3A, the ignition pulse signal detected by the ignition pulse detector 4 is input to the waveform shaper 5, FIG.
As shown in (b) , the waveform shaper 5 generates a rectangular wave signal having a duty ratio of 50%. As shown in FIG. 3C , a triangular wave signal is generated by integrating the rectangular wave signal by the integrator 6, and the triangular wave signal is digitally converted by the A / D converter 7, and then is converted by the reference signal generator 8.
Is input to The average effective value of the triangular wave signal is calculated by the rectifier 9 and the smoothing circuit 10 in the reference signal generator 8, and the divider 11 divides the triangular wave signal by the average effective value, as shown in FIG. , The amplitude of the triangular wave signal is adjusted to be constant. Further, the divider 1
By multiplying the triangular wave signal output from 1 and the signal from the waveform shaper 5 by the multiplier 13, FIG.
As shown in (1), a sawtooth signal is generated by inverting a triangular signal with a rectangular signal. The sawtooth signal is used as information representing an angle that is an integral multiple of the engine rotation angle, and based on this information, a sine wave signal as a reference signal x is generated by the sine wave generator 14 as shown in FIG. Generated. By generating the reference signal x as described above, a sine wave signal can be obtained without the need for a conventional tracking filter or counter, and the reference signal x necessary for controlling engine noise can be obtained with a simple circuit configuration and It can be generated quickly by arithmetic processing. In this embodiment, since the speaker 2 in the existing audio device is used, it is only necessary to add the microphone 1, the reference signal output device 3, the speaker signal generation device 15 and the like to the audio device, and the implementation is inexpensive. it can. The configuration of the triangular wave generation circuit 12 in the reference signal output device 3 may be changed as shown in FIG. That is, the rectifier 9 and the smoothing circuit 10 calculate the average effective value of the signal based on the output signal of the divider 11, return the average effective value to the divider 11, and adjust the amplitude of the triangular wave signal to be constant. I have to. In this case, the same operation and effect as in the above embodiment can be obtained. The present invention can be applied to vehicles other than automobiles. As described above, according to the first aspect of the present invention, a vehicle interior sound detecting means for detecting a vehicle interior sound and a speaker for generating a sound in the vehicle interior are provided. Based on a reference signal related to the vibration of the engine as a noise source, a vehicle noise control device that generates an output signal to a speaker so as to reduce the sound detected by the vehicle interior sound detection means. Input the ignition pulse signal to the waveform shaper to generate a square wave signal.
The triangular wave signal is generated by integrating this rectangular wave signal with an integrator, and the triangular wave signal is input to a divider, and a rectifier and
The average rms value passed through the smoothing circuit
Adjust the triangle wave signal and the signal from the waveform shaper
Is multiplied by a multiplier, and the triangular wave signal is
Ri is inverted to generate a sawtooth signal, since to generate a sine wave signal as the reference signal based on the saw-tooth wave signal, a reference signal necessary for controlling the engine noise, a tracking filter Ya It can be generated quickly with a simple circuit configuration and arithmetic processing without the need for a counter.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of an electric circuit showing a main part of a reference signal output device according to an embodiment of the present invention. FIG. 2 is a block diagram of an electric circuit showing an overall configuration of the noise control device. FIG. 3 is an explanatory diagram showing a process of generating a reference signal of engine noise. FIG. 4 is a plan view showing a layout of devices for an automobile. FIG. 5 shows a modification of the reference signal output device.
FIG. FIG. 6 is a diagram corresponding to FIG. 2 showing a conventional example. [Description of Signs] 1… Microphone (vehicle interior sound detection means) 2… Speaker 3… Reference signal output device (reference signal output means) 4… Ignition pulse detector 5… Waveform shaper 6… Integrator 8… Reference signal generation vessel 9 ... rectifier 10 ... smoothing circuit 11 ... divider 12 ... triangular wave generation circuit (triangular wave generating means) 13 ... multiplier 14 ... sinusoidal wave generator (sine wave generating means) 15 ... speaker signal generator device 17 ... microphone amplifier 20 ... Speaker amplifier 21 ... Controller 32 ... Cabin x ... Reference signals e1 to eM ... Microphone signals y1 to yL ... Speaker signals

Continuation of the front page (56) References JP-A-2-54678 (JP, A) JP-A-2-192209 (JP, A) JP-A-53-36162 (JP, A) JP-A-49-90070 (JP) JP-A-3-123105 (JP, A) JP-A 61-1749 (JP, U) JP-A 60-93332 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB Name) G10K 11/178 B60R 11/02 H03B 28/00 H03K 4/08 H04R 3/00 310

Claims (1)

(57) [Claims] [Claim 1] Vehicle interior sound detecting means for detecting vehicle interior sound, a speaker generating sound in the vehicle interior, and outputting a reference signal related to engine vibration in the vehicle And a speaker signal generating means for generating an output signal to a speaker based on the reference signal from the reference signal outputting means so as to reduce the sound detected by the vehicle interior sound detecting means. in the noise control device for a vehicle, the reference signal output means inputs an ignition pulse detection means for detecting an ignition pulse signal of the engine, an ignition pulse signal detected by the ignition pulse detecting means to the waveform shaper rectangular wave
A triangular-wave signal generating means for generating a triangular-wave signal by integrating the triangular-wave signal, and dividing the triangular-wave signal generated by the triangular-wave generating means.
Average rms value input through a rectifier and a smoothing circuit
The amplitude of the triangular wave signal is adjusted to be constant based on the
Multiplied by the adjusted triangular wave signal and the signal from the waveform shaper.
By multiplying by a calculator, the triangular wave signal is
And a sine wave generating means for generating a sine wave signal as a reference signal based on the sawtooth signal generated by the sawtooth wave signal. A noise control device for a vehicle, comprising: