JPH02306845A - Device for reducing vehicle indoor noise - Google Patents

Abstract

PURPOSE:To rapidly cope with various changes of vehicle conditions by determining the frequency of each filter according to the engine speed of an engine, comparing the filter output with a standard sound pressure every rotation order component, and correcting phase and sound pressure control quantities in such a manner as to minimize noise. CONSTITUTION:The sound pressure level outputted from a speaker 8 is offset by various indoor noises caused by engine rotation such as stuffy noise, but it is still imperfect to real-time noise change of a vehicle. The indoor noise remaining not offset is detected by a mike, and the detected sound pressure level is amplified by an amplifier 57. It is contracted to a determined band by band-pass filters 101-10n every order component, and correction parts 54b1-54bn and correction parts 55b1-55bn further correct the values obtained by processing the outputs of oscillators 61-6n in processing parts 54a1-54an and processing parts 55a1-55an for respective rotation order component, and impart the resulting values to a speaker 8, whereby feedback is applied.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a device for reducing noise inside a vehicle, and more particularly to a device for actively reducing low-frequency noise in a closed space such as an automobile that has a periodic sound source. It is something.

[Conventional technology]

Noise inside a vehicle such as a car is caused by the resonance phenomenon that occurs in the cabin, which forms a closed space, under certain conditions.
The vibrational force that is the cause of this is thought to be due to the rotational vibration component of the engine.

The measures initially taken to reduce such noise were passive, such as improving the coupling rigidity of the engine system, which is the source of vibration, and improving the coupling rigidity of the transmission system. The company tuned each mount, adjusted the panel rigidity for the sounding element inside the vehicle, and also installed mass dampers, dynamic dampers, etc. on the resonant parts to prevent resonance.

Such passive means have resulted in an increase in cost and weight, and their effects have not been fully satisfactory.

For this reason, JP-A-48-82304 and JP-A-59
Devices capable of actively reducing noise have been proposed in Japanese Patent Publications No. 9699-9699 and the like.

In particular, the latter Japanese Patent Application Laid-Open No. 59-9699 describes a four-cylinder vehicle in which muffled noise is a problem. Process the signal in various ways,
By separately adding a sound from a speaker that has the opposite phase and the same magnitude as each frequency component (rotational order component) of the noise observed at the driver's listening point in the vehicle interior, the sound can be heard through the interference effect. This offsets and reduces the noise level at the point.

(Problems to be Solved by the Invention) However, the above conventional example is a device for reducing only the muffled noise caused by the secondary component of engine rotation (one explosion component) of the noise inside the vehicle. , even if there is a noise component caused by a rotation order component (explosion order component) other than the rotation second order component (explosion first order component) due to engine explosion (rotation), it cannot be removed and noise reduction is impossible. It doesn't become something.

In addition, it is constantly affected by changes over time in the vehicle's engine system, mounting system, electrical system, etc., changes in the temperature characteristics of the electrical signal system, changes in the number of occupants, changes in the cabin temperature, etc., and the intrusion of some external disturbance. There was a problem that it was impossible to deal with the problem or the immediate response of the control could not be obtained.

Therefore, an object of the present invention is to realize a device that can remove not only muffled sounds in a vehicle interior but also noise components other than muffled sounds, and can quickly respond to various changes in vehicle conditions.

[Means for Solving the Problems] In order to achieve the above object, the vehicle interior noise reduction device according to the present invention includes a means for detecting a rotational order component due to an explosion of the engine, and a means for detecting a rotational order component due to an explosion of the engine, and a means for detecting a rotational order component due to an engine explosion. a plurality of oscillators provided to generate a sine wave output, and a sine wave output of the oscillator having a predetermined rotational order component corresponding to the engine rotational speed detected by the detection means, synchronized with the engine rotation, and the predetermined rotational order. A control means for processing each of the sine wave outputs according to pre-stored phase and sound pressure control amounts for the components, an amplifier for amplifying the output of the control means to drive a speaker, and a microphone for detecting the level of noise inside the vehicle. , a filter for each rotational order component through which the microphone output passes, and the control means determines the frequency of each filter according to the engine rotational speed and calculates the filter output and a reference sound pressure for each rotational order component. The phase/sound pressure control amount is corrected so that the noise is minimized by comparison.

(Function) Figure 12 shows the rotation of 1 to 8 caused by the explosion of a 4-cylinder engine.
A waterfall diagram showing the sound pressure level of the next component.
These rotational order components cause vehicle interior noise, and these rotational order components are generated based on the inertial force of the piston and the explosive force within the cylinder.

Therefore, the ignition (ignition) point of the engine that brings about such each rotational order component is determined, and the delay time Li (the first
3 (see Figure 3 (a))) and ignites it (ignition).
By controlling the phase of the sine wave signal from the oscillator synchronized with the time, the engine cabin noise component can be reduced.

On the other hand, the time α from the top dead center (hereinafter referred to as TDC) to the ear, which is the listening point, for the rotational order component shown in FIG. 13(a) is the transmission of nonlinear characteristics from engine mount → cab → cabin space. It depends on the route and is considered to be an approximately constant time.

Therefore, how far should the phase of the sine wave signal from the oscillator synchronized with the engine rotation (TDC) be advanced for each rotational order component to reduce the noise as the time from ignition (ignition) to TDC becomes ti-α? What is necessary is to measure in advance in accordance with the engine rotational speed and store it in the control means as the phase side it.

In addition, in order to optimally reduce static noise, it is necessary not only to control the phase but also to control the sound pressure corresponding to the sound pressure of the noise (reverse phase control). Is the sound pressure side measured in advance according to the engine speed for each component and used as a control means? Store it as 3H5t.

Then, an oscillator is prepared for each rotation order component shown in FIG. A control means energizes the oscillators corresponding to all rotation order components corresponding to the engine rotation speed and synchronizes the sinusoidal output signal with the engine rotation.

Also, the phase control amount and sound pressure side stored in the control means? 1
Of flt, the phase control amount and sound pressure control 3'g amount in the predetermined rotational speed order component corresponding to the detected current engine rotational speed are output.

The control means controls this phase control Hi and the sound pressure side (21
By processing the oscillator's sine wave output signal of each corresponding rotational speed order component using 1M, and amplifying these processed signals with an amplifier, a signal component that can eliminate the noise of a predetermined rotational order component is output from the speaker. It will be output.

In this way, it is ideal that the signal output from the speaker by the feedforward control iR can reduce the noise of all rotational order components without any control deviation, but as mentioned above, vehicle conditions change variously, so this is not possible. To respond quickly, it is necessary to further apply feedback to the speaker output for correction.

Therefore, in the present invention, a microphone is provided to pick up the cabin noise caused by the engine rotation (explosion) that remains and cannot be canceled out even with the above control, and the signal picked up by this microphone is fed back to the control means to control the noise. The jlU means uses the noise level and the reference sound pressure determined in advance for each rotation order component to determine the phase control amount and sound pressure side determined above so as to minimize the cabin noise based on the engine rotation. To more completely and quickly reduce vehicle interior noise by correcting lff1.

Particularly in this case, a filter for passing the output of the microphone is provided for each rotational order component, and the control means controls the control target frequency in each rotational order component according to the engine rotational speed from the engine rotational speed detection means. The passing frequency of each filter is determined and applied to each filter, and the output that has passed through each filter is compared with the reference sound pressure set for each rotational order component to perform a correction operation to minimize the noise inside the vehicle. conduct.

Therefore, the band of each rotational order component is narrowed, and highly accurate feedback control can be realized.

〔Example〕

FIG. 1 shows the overall configuration of a vehicle interior noise reduction device according to the present invention, in which 1 is a car, 2 is an engine of the car 1, 3 is a crank angle sensor of the engine 2, and 4 is a sensor for the engine 2. The installed temperature sensor, 5 is a controller as a control means that performs predetermined calculations based on the outputs of sensors 3 and 4, and 61 to 6R (n>1) are components of each rotational order (1st to 8th order) shown in Fig. 12. n oscillators are prepared in the controller 5 correspondingly and output a sine wave signal synchronized with engine rotation, and 7 amplifies and synthesizes each output of the oscillators 61 to 6m from the controller 5 to drive the speaker B. 9 is a microphone for detecting the sound pressure level of noise inside the vehicle, and 10, to 10. ．． is connected to the controller 5 and is connected to a band-pass digital filter (B
, P, P,). In this embodiment, a four-cylinder engine is used, and the crank angle sensor 3 is the second one.
As shown in the figure, for example, means for detecting each rotational order component from the number of rotating gears within a reference time of a magnetic gear 12 provided coaxially with the crankshaft 11 is configured.

Furthermore, the signal line of the engine temperature sensor 4 is shown as a dotted line because it is not essential.

FIG. 2 shows an embodiment in which the controller 5 in the vehicle interior noise reduction device shown in FIG. and a condition determining section 52 that inputs this engine rotation speed (and the engine temperature from the temperature sensor 4 as necessary) and makes various condition determinations; a ROM 53 that outputs a phase control amount φ and a sound pressure control amount G for each order component of the engine speed according to the engine speed; and an oscillator 6.
．． ~ Is the phase of each sine wave output signal from 6o each phase system from ROM53? 11 phase control section 54 controlled by the amount φ
and an oscillator 6. A sound pressure control section 55 controls the sound pressure of each sine wave output signal from 6I to 6o using a sound pressure control amount G from a ROM 53, and a phase/sound pressure controlled oscillator 51 controls the sound pressure of each sine wave output signal from 6I to 6o. A bandpass digital filter (B, P, F,
)56.

Note that 57 is an amplifier (preamplifier) that amplifies the output signal of the microphone 9, and the output of this amplifier 57 is passed through a band pass filter 10. ~10. However, according to the frequency band determined by the condition determining unit 52 according to the engine rotation speed from the crank angle sensor 3, each rotational order component from 1 to n is appropriately passed through the band to be controlled by the phase control unit 54 and the sound pressure control unit. 55.

In addition, in FIG. 2, n outputs of the bandpass filter 56, the amplifier 76, the phase control section 54, and the sound pressure control section 55 are individually processed, and the amplifier 7 synthesizes these outputs and supplies them to the speaker 8. It may be configured as follows.

Further, the phase control unit 54 changes the output of the oscillation RW 6 + to 67 to I? Phase processing section 54a that processes using the output of 0M53
, ~54a7, and these phase processing parts 54a, ~54a
The output of 7 is further filtered 10. It includes phase correction sections 54b and 54b7 that correct by the output of 10o,
The sound pressure control section 55 includes an oscillator 6. ~6. ．． The output of ROM5
Sound pressure processing section 55a, ~55a,
Then, the outputs of these sound pressure processing units 55a, 55aA are further passed through a filter 10. -1o, and sound pressure correction sections 55b1 to 55b, l.

Next, an explanation will be given of the operation of the embodiment in the case where the engine temperature from the temperature sensor 4 shown in FIG. 2 is not used.

First, the counter section 51 counts engine rotation speed pulses (corresponding to TDC) from the crank angle sensor 3 and provides them to the condition determination section 52, and the condition determination section 52, which has input this engine rotation speed, The oscillators 61 to 6.
The oscillators selected from among the oscillators are controlled so that each sine wave output signal is generated in synchronization with the TDC of the engine rotation.

The rotational order components to be selected in advance in this case are explained using the three-dimensional graph diagram (waterfall diagram) in Fig. 12. The rotational order components shown in the figure are due to the engine rotation (explosion); , in this example, rotation 2~
4 (A-H of the 2/2.5/3/3.5n order components
is selected based on the fact that it has the highest sound pressure level of vehicle interior noise.

Therefore, n oscillators 61 to 6. is 6. ~64(7)
Four (n-4) oscillators should be prepared.
In the IIfD range ■, the oscillator L corresponds to the oscillator L, and the oscillator 6.
．． 6. ), and in the control range ■, the rotational quadratic component C
Oscillators 61 to 6.corresponding to the rotation 2.5-order component, the rotation 3-order component E, the rotation 3.5-order component F, and the rotation 4-order component H. is selected, and a sine wave output signal synchronized with engine rotation is generated.

Therefore, when the condition determining unit 52 confirms that the engine speed detected by the crank angle sensor 3 belongs to the control) 1 target range shown in FIG.
All rotational order components from 3 (2/2°5/3/3.
The phase control amount φ and the sound pressure control amount G for each of the rotation order components corresponding to the current engine rotation speed in the fifth order component)
Select and read out.

Here, to explain the ROM53, this ROM5
The map stored in Figure 3 is based on phase and sound pressure control so that the protruding parts of each rotational order component in Figure 12 become smaller. l
1 fft (control 2 based on the sine wave output from the oscillator)
For example, by varying the output of one of the n oscillators and fixing the other oscillators, the engine rotation in the rotational order component related to that variable oscillator is determined experimentally. It is formed by the phase control amount φ and the sound pressure control 4'JLfflG obtained for the number.

In the ROM 53 formed in this way, the phase control amount φ and the sound pressure control amount in all rotational order components corresponding to the engine rotational speed from the condition determination unit 52 are stored. 1llG(
phase control unit 54 and sound pressure control unit 5.
5 processing parts 54a, ~54a, and processing parts 55a1~
55a7, respectively, and the oscillators 61-6. Each sinusoidal output signal synchronized with the engine rotation (TDC) from 1 is processed, the phase is delayed by a corresponding predetermined value, and a bandpass filter 56 is applied with an original waveform that reduces sound pressure to the maximum extent possible.
is applied to amplifier 7 via. The amplifier 7 adjusts the human signals to the optimum volume, synthesizes them, and outputs them from the speaker 8.

In this way, the sound pressure level output from the speaker 8 can cancel out various noises in the vehicle interior caused by engine rotation, including muffled sounds, but it can also compensate for real-time noise changes in the vehicle. is still incomplete.

Therefore, the noise inside the vehicle that still remains without being canceled out is detected by the microphone 9, and the detected sound pressure is amplified by the amplifier 57, and the band-pass filter IL-
10□ to narrow down to a predetermined band, and the correction units 54b1 to 54b,
, and the correction units 55bl to 55b7 output the oscillators 6. -6. Processing part 54a
I~54a,.

Then, the values processed by the processing units 55at to 55a6 are further corrected and fed back to the speaker 8. Note that in the above embodiment, n=4.

Bandpass filter 10. Regarding the operations in steps 106 to 106, first, as shown in FIG.
), the frequency band for each order component corresponding to this engine speed is determined from the map shown in FIG. 12 (Step T2)
Then, this determined frequency band is applied to each filter 10.
~10. .

(step T3).

Now, looking at FIG. 12, in the case of the engine rotation 2 component, regions A, B, and C are the control target regions, but for example, in the illustrated engine rotation speed X rps, about 110Hz of region C Filter 10. is assigned to the second-order component as the filter frequency. give to As shown in Figure 12,
If we control up to the area H of the 4th order component, in the case of Xrpso, we will control the area MC of the 2nd order component, the overlay of the 2.5th order component, the area F of the 3rd order component, and the area F of the 4th order component. The pass frequency band for the engine speed in region H is determined by each filter 10. ~1
It will be set to 0.

However, at this time, it is not necessary to accurately determine the pass band for each engine speed; for example, if the engine speed is 30 rρm,
Alternatively, it may have a width such as 60 "p-".

When the frequency band is set and given to each filter in this way, each filter uses the given frequency as the bandpass filter 101 to 10 as a digital filter.
4 controls the tap coefficients (not shown) to pass only the microphone output of each frequency band, and correctors 54b, -54
b7 and the correction units 55b1 to 55b.

Therefore, compared to the case where, for example, the rotational second to fourth order components up to 40011z are controlled as shown in FIG. 13, and only one fixed type filter common to all order components is used, the frequency band of each filter is narrowed. This means that good characteristics against noise can be obtained.

FIG. 4 shows correction units 54b1 to 54b7 and correction unit 551)
4 is a flowchart showing the correction algorithm from + to 55b7. Hereinafter, the correction operation of the present invention will be explained with reference to FIG. Note that this correction operation may be performed sequentially for each correction section, but it is better to perform it simultaneously for better responsiveness.

First, target values are determined in the )m pressure sections 54b and 54bfi (step Sl).

In order to determine this target value, the correction units 54b, ~54b7
As shown in Fig. 5, the effect of active control, which has been experimentally determined in advance for each rotational order component corresponding to the engine speed, can be fully felt by the sound pressure level +! Standard level STD (However, this is only the initial target (direct, not necessarily direct) at the start of feedback control, and the target sound is changed according to the current engine speed. A pressure level is determined.

Next, this target sound pressure level STD is compared with the actual sound pressure level X+ (i is the time of detection) detected by the microphone 9 (step S2). If it is, it is assumed that sufficient noise cancellation processing has already been performed and the feedback process is terminated (step 33), but if not, phase correction is executed (step S4). In this case, 1 of the phase correction amount is A unit is determined in advance, and the outputs of the processing units 54a1 to 54a5 are phase-corrected by an amount of phase correction that is +m times the unit.

This is to find the direction of the target value by performing large control and determine the direction of control.

Through this phase correction, it is checked whether the detected sound pressure xt has fallen below the target value STD (Step S5), S
When the TD is turned off, the control width is reduced to correct the phase by +1 unit (step S6), and the detected sound pressure is determined to be the same by comparing the current value and the previous value. Detect (steps S7, S8).

In step S5, if the detected sound pressure x1 has not reached the target (direct STD), it is determined that the control direction is the opposite, and the phase correction of m times the unit phase side ?111 amount is performed in the same way in the opposite direction. (Step S9).

Step S10) Check whether the detected sound pressure XI has fallen below the target value STD due to this phase correction.
, when the STD is turned off, the control width is reduced to correct the phase correction by 11 units (step 511), and the value at which the detected sound pressure is the same is determined by comparing the current value and the previous value. Detect (step S12.513).

The state of the above control is shown in the graph of Fig. 6, and the target value STD stored in each correction section is shown by a solid line. The pressure X, is controlled 2'i, and finally the target (laS T
Control is performed so that the value exceeding D (indicated by the dotted line) is set as the optimum value, that is, the minimum value.

It is more preferable to perform learning so that the optimum value obtained in this way is used for the next control.

After the phase correction operations in the correction units 54b1 to 54b9 are performed in this way, the correction unit 55
The same control as in steps S1 to S313 described above in steps S1 to S313 in b, ~55b7 is performed for the sound pressure.

FIG. 7 shows another embodiment, in which
This is an attempt to more precisely reduce noise by using the engine temperature from the temperature sensor 4 shown by the dotted line in FIG.

That is, the delay time ti shown in FIG. 13(a) is equal to fb in the same figure.
) to (d), as shown in 1 to t3, it increases as the engine temperature increases (the ignition point in the case of a diesel engine is delayed).

This is because when the temperature decreases, it takes time to atomize the fuel necessary from the time of injection to ignition and to raise the temperature of the combustion chamber.

Therefore, when controlling the phase of vehicle interior noise, it is necessary to take temperature into consideration.

Furthermore, in order to optimally reduce vehicle interior noise, it is necessary not only to control the phase, but also to control the sound pressure (reverse phase control) that corresponds to the nuisance noise in the vehicle interior. to be influenced.

In other words, when the engine temperature is low (during warm-up in a cold state), the time from injection to ignition is long, and since combustion starts all at once, the sound pressure of the muffled sound due to the diesel engine noise increases. As the engine gradually warms up, the diesel noise decreases and the noise sound pressure decreases.

After warming up, as the engine temperature increases, the fuel viscosity decreases due to the increase in the temperature of the fuel itself and the temperature of the fuel pipe, and the fuel injection rate decreases. For this reason, the amount of fuel is normally increased to compensate for the decrease in output, but the amount increases too much, causing the cylinder pressure to rise and the noise sound pressure to increase.

In this way, as shown in Figure 7, to reduce cabin noise, the engine temperature (detected by a cooling water temperature sensor or fuel temperature sensor installed in the engine) is detected, and as a result of this temperature change, the engine temperature is detected. Preferably, the phase and sound pressure are controlled.

Therefore, how to control the phase and sound pressure of the sine wave signal synchronized with the engine rotation according to the engine rotation speed and engine temperature may be determined in advance and stored in the control means.

For this reason, in FIG. 7, if another ROM 60 is prepared and the phase and sound pressure are processed from the sine wave signal from the oscillator synchronized with the TDC signal output from the condition determining section 52, it is possible to It is possible to reduce the noise inside the vehicle.

To create the map stored in the ROM 60 in the example shown in FIG. 12, first, the sine wave output signal of the oscillation H61 (synchronized with the engine rotation) regarding the second-order component of engine rotation is shown in FIG. In the control target range, a noise reduction experiment is conducted for engine rotation speed at predetermined intervals (for example, 100 rps+) and engine temperature at predetermined intervals (for example, 10''C) (however, other oscillator outputs are stopped), Phase control i
A ROM map can be created.

Then, the oscillator 6° for the 2.5th order component is
1 and perform a similar experiment to find the phase of the 2.5th order component 'tJN
111 ffl Create ROM map. In this way, the phase control amount R for all four oscillators 61 to 64 is
Create an OM map.

Regarding the sound pressure G, we conducted experiments in the same manner for engine speeds and engine temperatures that fall within the control target range shown in Figure 12, and successively determined the sound pressure that would reduce the noise the most at the listening point. Sound pressure: t: (I?711 M
We can help you create a ROM map.

The ROM map 60 created in this way is based on the engine speed input to the condition determination unit 52, and the phase control amount at the current engine temperature for all rotational order components corresponding to the engine speed.・The phase control unit 54 controls the sound pressure control amount with respect to the output from the corresponding oscillator.
, and the sound pressure control section 55, optimal noise reduction can be achieved.

However, when the engine temperature changes from low temperature to normal temperature to high temperature, normally the water temperature does not rise at room temperature after 11 aircraft, so low temperature to normal temperature is controlled by water temperature, and normal temperature to high temperature is controlled by fuel temperature. It is necessary to control the Note that it is also possible to perform control using the intake air temperature during the switching from water temperature to fuel temperature.

By performing phase and sound pressure control based on temperature changes, for example, compared to performing only muffled sound control determined at room temperature for all temperatures, in water temperature control mode, as the temperature decreases, The effect of reducing muffled noise becomes greater, and in the fuel (intake temperature) control mode, the effect of reducing muffled sound becomes more noticeable as the temperature rises above room temperature.

In the above embodiment, a ROM of engine speed-phase/sound pressure with engine temperature as a parameter for each order component is used.
It is necessary to create a map, which results in a fairly large amount of data.

Therefore, instead of converting everything into ROM as described above, each output of the ROM 53 used in the embodiment shown in FIG. 2 may be temperature-corrected by using, for example, an analog correction circuit based on the engine temperature. .

That is, when the condition determining unit 52 gives the engine speed to the ROM 53, the ROM 53 reads out the phase control amount and the sound pressure control amount from the ROM map of each order component having the engine speed within the control range. The correction circuit is given the engine temperature from the condition determining section 52, and the phase and sound pressure corresponding to this engine temperature are determined by the phase system from the ROM 53. TII quantity and sound pressure output are added to the corresponding oscillators 61 to 6. The phase control unit 54 controls the output of the sound pressure? It can be processed at the 1j section 55.

In addition to the above embodiments, by preparing a ROM that takes into account the load detected using each load sensor and performing similar sound pressure control, it is possible to further cancel out the noise that varies depending on the load. becomes possible.

That is, in a diesel engine, for example, as the load increases, advance angle correction is performed by the load timer and the sound pressure also increases.

On the other hand, in the case of the above embodiment, the oscillator output is controlled based on the engine temperature based on the TDC of the engine rotation from the crank angle sensor 3, but even if this engine temperature is not measured, the noise can be reduced. It is more direct and preferable to detect the engine ignition or ignition explosion timing itself, which is the main factor, and control the phase and sound pressure.

Therefore, in the embodiment shown in FIG. 8, in the case of a diesel engine, a single ignition sensor 80 or a plurality of ignition sensors 80 are installed as shown in FIG. 9, and the sensor output waveform (FIG. 10 (a) )), and upon receiving this ignition output waveform, the condition determination unit 52 detects the engine rotation speed based on this signal and forms a shaped waveform ((b) in the same figure).
A reference signal is sent to each applicable oscillator. (In addition, since the condition determination unit 52 detects the engine speed based on the ignition output waveform, in this case, the rank angle sensor as shown in FIG. 2 is not necessary.) The oscillator that receives the reference signal outputs a sine wave ( (C)), and this sine wave output is stored in the ROM 53 as a phase control 1711Ll? of the corresponding rotational order component according to the engine rotational speed.
) Oppression: By reading and processing IIIFfi and generating speaker output ((d) in the same figure), more accurate position 1 can be obtained.
■・Sound pressure can be controlled.

When forming the ROM 53 used here, T
Instead of DC, the sensor output waveform (a) is used as the engine l timing pulse (bl), and the phase and sound pressure of the sine wave output waveform (C) are processed in the same way as in the case of Fig. 2 (engine temperature is not required) (d ) can be determined by experiment.

FIG. 11 shows the case where the ignition sensor 80 is used and the case where the fixed reference point (
TDC) is shown, and the shaded area shows that as the temperature rises, the volume reduction decreases.

If the ignition sensor is used in this way, control that takes into account at least the transmission characteristics of the engine mount system will suffice.

In addition, in the embodiments shown in FIGS. 7 and 8 described above, the second
Processed parts 54a1 to 54a1 and 55a+ to 5 as shown in the figure.
5an and correction units 54bl to 54b, 1 and 55b
Needless to say, processing and correction are performed according to steps 1 to 55b7.

〔Effect of the invention〕

As described above, the vehicle interior noise reduction device according to the present invention uses a plurality of oscillators corresponding to the rotational order components caused by engine explosion, and uses a plurality of oscillators to control noise according to engine rotation.
Detects the rotation order component to be generated and synchronizes the sine wave output from the corresponding oscillator with the engine rotation, and also uses a phase system that is stored in advance for each rotation order component. 3'jl and sound pressure control amount, and detect the cabin noise with a microphone, and pass the microphone output of the frequency band of each rotational order component determined according to the engine rotation speed to generate the noise for each rotational order component. Is the phase control amount and sound pressure controlled so that the noise is minimized by comparing it with the reference sound pressure? Since the configuration is configured to correct the amount of Il, it is possible to reduce not only the engine muffled noise but also other cabin noise as a whole caused by engine rotation (single engine), which cannot be offset by feedforward control. Even residual noise can be quickly minimized using feedbank control. Furthermore, since it is possible to extract the noise of the targeted frequency for each rotational order component, the device becomes resistant to unnecessary noise picked up by the microphone (good S/N), achieving even faster noise reduction. .

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of a vehicle interior noise reduction device according to the present invention. FIG. 2 is a block diagram showing a controller in an embodiment of the present invention in particular functionally. is a flowchart for determining the frequency band of the bandpass filter for each rotational order component used in the present invention; FIG. 4 is a flowchart showing an algorithm for phase/sound pressure correction according to the present invention; The figure is a graph showing the characteristics of the engine speed and target sound pressure for each order component of the engine speed in the present invention. Figure 6 explains the thorough sound pressure control according to the present invention. 7 is a block diagram showing the controller in a particularly functional manner in another embodiment; FIG. 8 is a block diagram showing the controller in a particularly functional manner in yet another embodiment; 9 is a diagram showing the arrangement of the ignition sensor, FIG. 10 is a waveform diagram when the output pulse of the ignition sensor is used as the reference timing, and FIG. 11 is a graph diagram showing the effect when using the ignition sensor. FIG. 12 is a three-dimensional graph diagram showing a control target region in terms of engine speed according to the present invention, and FIG. 13 is a waveform diagram for explaining a shift in ignition timing during advance angle correction. 1 and 2, I is a car, 2 is an engine, 3 is a crank angle sensor, 5 is a controller, 6. ~6
．． is an oscillator, 7 is an amplifier, 8 is a speaker, 9 is a microphone,
10. ~1011 is a band pass filter, 54 aI~5
4 a+ and 55al to 55a are processed parts, 54b
1 to 54ba and 55b1 to 55b respectively indicate correction units. In the figure, the same reference numerals indicate the same or i111 portions.

Claims (1)

[Claims] A means for detecting a rotational order component due to an explosion of the engine, a plurality of oscillators that are provided corresponding to the rotational order component and generate a sine wave output, and a predetermined rotational speed corresponding to the engine rotational speed detected by the detection means. A control means for synchronizing the sine wave output of the oscillator of the order component with the engine rotation and processing the sine wave output using pre-stored phase and sound pressure control amounts for the predetermined rotation order component, and the output of the control means. an amplifier that amplifies and drives a speaker, a microphone that detects the level of noise inside the vehicle, and a filter for each rotational order component that passes the output of the microphone, and the control means controls each rotational order component according to the engine rotational speed. A vehicle interior noise control system characterized by determining the frequency of a filter, comparing the filter output with a reference sound pressure for each rotational order component, and correcting the phase/sound pressure control amount so that the noise is minimized. Reduction device.