1. Field of the Invention
The present invention relates to a vehicular active noise/vibration/sound control system having at least two of an active noise control apparatus (hereinafter referred to as “ANC”) for reducing noise in a vehicle cabin based on a detected signal representative of engine vibrations, an active vibration control apparatus (hereinafter referred to as “AVC”) for reducing vehicle vibrations based on the above detected signal, and an active sound control apparatus (hereinafter referred to as “ASC”) for generating a sound effect in the vehicle cabin based on the above detected signal, and a vehicle incorporating such a vehicular active noise/vibration/sound control system.
2. Description of the Related Art
Noise that is primarily generated by explosions in the engine 12 is perceived by the ears of passengers seated on front and rear seats of the ANC-mounted vehicle 10N. Microphones 18, 20 are fixedly positioned on the interior roof or upper portion of seats near the ears of the passengers. Speakers 22, 24 fixedly mounted in the ANC-mounted vehicle 10N near the front and rear seats radiate canceling sounds for minimizing the sounds (noise) that are applied to the microphones 18, 20. The ANC 16 generates control signals S1, S2 that are supplied to the speakers 22, 24 to radiate the canceling sounds.
The ANC 16 comprises a reference signal generator 26 for generating a sine-wave reference signal proportional to the frequency of engine rotation cycles from the engine rotation pulses Ep and a pair of adaptive filters 28, 30 for changing the phase and amplitude of the reference signal to generate the control signals S1, S2 to minimize output signals from the microphones 18, 20.
As shown in
The load sensors 46, 48 supply their output signals to the AVC 50. The engine rotation pulses Ep are also supplied to the AVC 50.
The AVC 50 comprises the reference signal generator 26 for generating a sine-wave reference signal proportional to the frequency of engine rotation cycles from the engine rotation pulses Ep and a pair of adaptive filters 52, 54 for changing the phase and amplitude of the reference signal to generate the control signals S3, S4 to minimize changes in output signals from the load sensors 46, 48.
The ASC-mounted vehicle 10S has an ASC 60 comprising the reference signal generator 26 for generating a sine-wave reference signal proportional to the frequency of engine rotation cycles from the engine rotation pulses Ep and a pair of acoustic controllers 56, 58 for changing the phase and amplitude of the reference signal to generate control signals S5, S6. The control signals S5, S6 are supplied to the speakers 22, 24 to cause the speakers 22, 24 to radiate a sound effect depending on the acceleration of the ASC-mounted vehicle 10S.
It may be proposed to install all the ANC 16, the AVC 50, and the ASC 60 in a vehicle to provide a more comfortable vehicle cabin environment.
There has been proposed a vehicular acoustic enhancement system including an ASC having a sound source for generating a sound effect and an ANC having an adaptive noise cancellation controller (see Japanese Patent No. 3261128). In the disclosed vehicular acoustic enhancement system, while the vehicle is being accelerated, the sound source outputs an accelerating sound simulating that of a high-output vehicle through a mixer and speakers, and the adaptive noise cancellation controller generates a noise cancellation signal based on a signal obtained from the engine and representing an engine rotational speed and a reference signal obtained from a microphone and supplies the noise cancellation signal to the mixer.
However, the vehicular acoustic enhancement system disclosed in Japanese Patent No. 3261128 is disadvantageous in that since the ASC and the ANC are activated at all times, they may interfere with each other depending on the running state of the vehicle, possibly impairing the noise and acoustic environment in the vehicle.
For example, when the ASC operates to emphasize the accelerating sound upon acceleration of the vehicle, the ANC operates to cancel the accelerating sound. As a result, the driver of the vehicle is unable to enjoy acceleration as is otherwise felt by the emphasized accelerating sound.
It is therefore an object of the present invention to provide a vehicular active noise/vibration/sound control system which has at least two of an ANC, an AVC, and an ASC and which is arranged to prevent the ANC, the AVC, and the ASC from interfering with each other to impair a vibratory acoustic (noise) environment, and a vehicle incorporating such a vehicular active noise/vibration/sound control system.
According to the present invention, there is provided an active noise/vibration/sound control system for use in a vehicle, having at least two of an active noise control apparatus for reducing noise in a vehicle cabin based on a detected signal representative of engine vibrations, an active vibration control apparatus for reducing vehicle vibrations based on the detected signal, and an active sound control apparatus for generating a sound effect in the vehicle cabin based on the detected signal, the active noise/vibration/sound control system comprising running state detecting means for detecting a running state of the vehicle, and coordination control means for controlling activation and inactivation of the active noise control apparatus, the active vibration control apparatus, and the active sound control apparatus or controlling control characteristics thereof in relation to each other, depending on the detected running state.
With the above arrangement, depending on the running state of the vehicle detected by the running state detecting means, activation and inactivation of the active noise control apparatus, the active vibration control apparatus, and the active sound control apparatus are controlled or control characteristics thereof are controlled in relation to each other. Therefore, in the active noise/vibration/sound control system having at least two of the active noise control apparatus, the active vibration control apparatus, and the active sound control apparatus, these apparatus are prevented from interfering with each other and hence a vibratory acoustic (noise) environment in the vehicle is prevented from being impaired.
The running state detecting means may have an engine rotation frequency detector for detecting an engine rotation frequency and a frequency change detector for detecting a frequency change in the detected engine rotation frequency, and the coordination control means may comprise a weighting variable calculator for calculating weighting variables for control signals to be applied respectively to the active noise control apparatus, the active vibration control apparatus, and the active sound control apparatus, based on the engine rotation frequency and the frequency change. The active noise/vibration/sound control system thus constructed is relatively simple in arrangement.
If the vehicle has a transmission selectively operable in an automatic transmission mode and a manual transmission mode, then the weighting variable calculator may change weighting variables for the control signal to be applied to the active sound control apparatus depending on whether the transmission operates in the automatic transmission mode or the manual transmission mode. With this arrangement, the control apparatus may be controlled in a manner matching the selected transmission mode, e.g., to generate a sound effect in the vehicle to give the passengers in the vehicle sporty feeling when the transmission is in the manual transmission mode.
According to the present invention, since activation and inactivation of the active noise control apparatus, the active vibration control apparatus, and the active sound control apparatus are controlled or control characteristics thereof are controlled in relation to each other by the coordination control means depending on the running state of the vehicle detected by the running state detecting means, the control apparatus of the active noise/vibration/sound control system having at least two of the active noise control apparatus, the active vibration control apparatus, and the active sound control apparatus are prevented from interfering with each other and hence the vibratory acoustic (noise) environment in the vehicle is prevented from being impaired.
If the transmission of the vehicle is selectively operable in the automatic transmission mode and the manual transmission mode, then the weighting variable calculator changes weighting variables for the control signal to be applied to the active sound control apparatus depending on whether the transmission operates in the automatic transmission mode or the manual transmission mode. Therefore, a sound effect matching the selected transmission mode can be generated.
The present invention is also applied to a vehicle incorporating an active noise/vibration/sound control system having at least two of an active noise control apparatus for reducing noise in a vehicle cabin based on a detected signal representative of engine vibrations, an active vibration control apparatus for reducing vehicle vibrations based on the detected signal, and an active sound control apparatus for generating a sound effect in the vehicle cabin based on the detected signal.
The above and other objects, features, and advantages of the present invention will become more apparent from the following description when taken in conjunction with the accompanying drawings in which preferred embodiments of the present invention are shown by way of illustrative example.
Preferred embodiments of the present invention will be described below with reference to the drawings. Those parts of the preferred embodiments which are identical to those shown in
As shown in
A detector, not shown, detects the frequency of rotation cycles of the main shaft of the engine 12, and produces engine rotational pulses Ep corresponding to explosion periods of the engine 12. The engine rotational pulses Ep are supplied through the engine ECU 14 to the noise/vibration/sound control ECU 100.
The engine 12 is installed on the vehicle chassis by engine mounts 42, 44. The engine mounts 42, 44 have respective load sensors 46, 48 doubling as vibration sensors and respective actuators (vibration actuators) 43, 45 which apply vibrations to the engine 12 through the respective engine mounts 42, 44.
A microphone 18 is fixed to the interior roof of the vehicle 102 at a transversely central position close to a passenger position 47, i.e., the position of an ear of the driver in the present embodiment. Speakers 22 for radiating acoustic sounds to passengers are fixedly mounted respectively on the inner panels of respective front doors on both sides.
Actually, other speakers are installed near rear seats and microphones are installed near rear-seat passenger positions, as shown in
The noise/vibration/sound control ECU 100 is supplied with the engine rotation pulses Ep, a reference signal Sr from the microphone 18, and a load signal Sk from the load sensor 48, and outputs a control signal Da as a drive signal for the actuator 45 and a control signal Sp as a drive signal for the speaker 22, respectively to the actuator 45 and the speaker 22.
As shown in
The frequency of the engine rotation pulses Ep (hereinafter referred to as “engine rotation frequency fe”) is supplied from an engine rotation frequency detector 106 to the AVC 50, the ANC 16, the ASC 60, etc. The engine rotation frequency detector 106 comprises a frequency counter or the like for detecting, i.e., calculating, the engine rotation frequency fe from the engine rotation pulses Ep, which are generated by a Hall device or the like when the output shaft of the engine 12 makes revolutions.
It is known that the frequency change Δaf is of a different value depending on which gear position the transmission of the vehicle 102 is in. Specifically, the frequency change Δaf is greater when the transmission is in a lower gear position and is smaller when the transmission is in a higher gear position.
The engine rotation frequency detector 106 and the frequency change detector 108 jointly make up a running state detecting means 136 according to the present embodiment.
The reference signal generator 126 generates a sine-wave reference signal Sn of harmonics (integral multiples and/(or) real number multiples ranging from the first to sixth harmonics) which matches the type of the vehicle 102 based on the engine rotation frequency fe.
Harmonics to be generated with respect to the adaptive filter 54 of the AVC 50 and the adaptive filter 28 of the ANC 16 are determined as follows: Gain characteristics (transfer characteristics defined by frequencies [Hz] on a horizontal axis and gains [dB] on a vertical axis) according to various vibration characteristics and noise characteristics of an entire system of the AVC 50 and the ANC 16 depending on the vehicle type to be applied are measured in advance. Then, the reference signal generator 126 generates a sine-wave reference signal Sn of one or more harmonics corresponding to the measured frequency range.
The acoustic controller 56 of ASC 60 is supplied with three reference signals Sn of orders corresponding to harmonics that are four, five, and six times, for example, the engine rotation frequency fe in order to produce a sporty sound effect (alternatively, a brisk sound effect or a massive sound effect) in view of human sensitivity.
A weighting variable calculator 110, which functions as a coordination control means, calculates weighting variables W1, W2, W3 to be set respectively in weighting units 121, 122, 123 that are connected between the output terminals of the AVC 50, ANC 16, and the ASC 60, and the actuator 45 of the engine mount 44 to be controlled and the speaker 22, based on the engine rotation frequency fe and the frequency change Δaf. Each of the weighting variables W1, W2, W3 has a value in the range from 0 to 1.
The weighting unit 121 weights a control signal Da output from the adaptive filter 54, and outputs a control signal Da×W1 to the actuator 45 to be controlled.
The weighting unit 122 weights a control signal Sp2 output from the adaptive filter 28, and outputs a control signal Sp2×W2 as the control signal Sp for the speaker 22 to be controlled.
The weighting unit 123 weights a control signal Sp3 output from the acoustic controller 56, and outputs a control signal Sp3×W3 as the control signal Sp for the speaker 22 to be controlled.
The control signal Sp for the speaker 22 is a combined signal (added signal) produced when the control signal Sp2×W2 and the control signal Sp3×W3 are combined with (added to) each other by an adder 124.
The adaptive filter 54 of the AVC 50 adaptively changes the amplitude and phase of the reference signal Sn to generate a control signal Da for reducing a change in the load signal Sk, based on the engine rotation frequency fe and the load signal (detected signal) Sk which has been detected by the load sensor 48 and converted into an electric signal, and outputs the generated control signal Da.
The adaptive filter 28 of the ANC 16 adaptively changes the amplitude and phase of the reference signal Sn to generate a control signal Sp2 for reducing the amplitude of the reference signal Sr which has been picked up by the microphone 18 and converted into an electric signal, based on the engine rotation frequency fe and the reference signal Sr from the microphone 18, and outputs the generated control signal Sp2.
Each of the engine rotation frequency detector 106, the frequency change detector 108, the load sensor 48, and the microphone 18 functions as a transducer.
The acoustic controller 56 of the ASC 60 comprises a flat corrector 128 and an order sound adjuster 130. The flat corrector 128 comprises three filters corresponding to the above orders, i.e., 4, 5, and 6, and having inverse gain characteristics which are an inversion of measured gain characteristics (defined by frequencies [Hz] on a horizontal axis and gains [dB] on a vertical axis, and referred to as “cabin sound field transfer characteristics”) from the reference signal generator 126 to the acoustic controller 56, the weighting unit 123, the adder 124, and the speaker 22 and from the speaker 22 to the passenger position 47 (the position of the microphone 18 in the present embodiment). In the flat corrector 128, these three filters adaptively change the amplitude and phase of the reference signals Sn of the orders 4, 5, 6 to generate respective control signals corresponding to the orders 4, 5, 6 for providing flat gain characteristics at the position of the microphone 18.
The order sound adjuster 130 of the ASC 60 comprises three adaptive filters corresponding to the respective corrected reference signals Sn of the orders 4, 5, 6 which are output from the flat corrector 128. The order sound adjuster 130 adaptively changes the amplitude and phase of the corrected reference signals Sn of the orders 4, 5, 6 and combines the reference signals Sn into a control signal Sp3 for controlling the speaker 22 to produce a sound effect depending on the engine rotation frequency fe.
A weighting variable W1 for the AVC 50, a weighting variable W2 for the ANC 16, and a weighting variable W3 for the ASC 60 shown in
According to the control apparatus inactivating and activating table 200 shown in
In a range (referred to as an accelerating range) in which the engine rotation frequency fe is high and the vehicle speed v is in a medium speed range and a high speed range for acceleration, only the ASC 60 is operated to generate a sound effect to give the driver and other passengers a sporty feeling, and the AVC 50 and the ANC 16 are inactivated to allow the driver and other passengers to realistically feel vibrations and noise generated on the vehicle 102 to enjoy active driving.
In a range (referred to as a cruising range) in which the engine rotation frequency fe is medium and the vehicle speed v is in the medium speed range and the high speed range for cruising, only the ANC 16 is operated to reduce noise, the AVC 50 is inactivated because vibrations are relatively small, and the ASC 60 is also inactivated as no sound effect for acceleration is required.
Since the ANC 16, the AVC 50 and the ASC 60 are controlled in a coordinated way as indicated by the control apparatus inactivating and activating table 200, vehicle cabin environment of vibrations, noise and sound is prevented from being impaired because the ANC 16, the AVC 50, and the ASC 60 are not independently controlled and are prevented from interfering with each other.
The map MP1 for the AVC 50 which has been tested many times on particular vehicle types and the vehicle 102 based on the index shown in
The map MP2 for the ANC 16 is arranged such that when the engine rotation frequency fe is low and medium and the frequency change Δaf is low and medium, the weighting variable W2 is set to 1 (Da=Da×W2) for effectively activating the ANC 16, and as the engine rotation frequency fe is higher and the frequency change Δaf is higher, the weighting variable W2 gradually changes from 1 to 0. When the engine rotation frequency fe is in a range higher than 90 [Hz], then the weighting variable W2 is set to 0 to inactivate the ANC 16. Therefore, the ANC 16 is inactivated in the accelerating range.
The map MP3 for the ASC 60 is arranged such that when the engine rotation frequency fe is low and the frequency change Δaf is low, the weighting variable W3 is set to 0 (Da=Da×W3) for inactivating the ASC 60, and as the engine rotation frequency fe and the frequency change Δaf are higher, the weighting variable W3 gradually increases for producing a greater sound effect.
As described above, the vehicle 102 incorporates the noise/vibration/sound control ECU 100 according to the first embodiment shown in
Depending on the running state of the vehicle 102 detected by the running state detecting means 136, the weighting variable calculator 110 as the coordination control means selectively activates and inactivates the ANC 16, the AVC 50, and the ASC 60 or controls the control signals Da, Sp2, Sp3 representing their control characteristics in relation to each other. Consequently, the ANC 16, the AVC 50, and the ASC 60 are prevented from interfering with each other and hence the vehicle cabin environment of vibrations, noise, and sound is prevented from being impaired.
In the above embodiment, the vehicle 102 incorporates all of the three control apparatus, i.e., the ANC 16, the AVC 50, and the ASC 60. However, the principles of the present invention are also applicable to a vehicle incorporating at least two of the above three control apparatus.
In such a case, the function of the control apparatus which is not incorporated in the vehicle may be deleted from the noise/vibration/sound control ECU 100 or may not be performed, and the control apparatus inactivating and activating table 200 (excluding the control apparatus which is not incorporated) shown in
As shown in
The weighting variable calculator 110A of the noise/vibration/sound control ECU 100A calculates weighing variables W1, W2, W3 (W3a or W3m) to be set respectively in the weighting units 121, 122, 123 which are connected to the respective output terminals of the AVC 50, the ANC 16, the ASC 60, based on the engine rotation frequency fe, frequency change Δaf, and the manual transmission mode signal Sm from the transmission shifter 112.
The CVT basically comprises a drive pulley engaging the output shaft of the engine 12 and a driven pulley operatively coupled to the drive pulley through a steel belt. The drive and driven pulleys have respective slots in which the steel belt engages, and the widths of the slots are changed to relatively change the diameters of the torque transmission pitch circles for the steel belt to continuously change the transmission gear ratio of the CVT.
The shifter 112, which is coupled to the CVT, has a shift knob 138 that can selectively be brought into a parking position P, a reverse position R, a neutral position N, a drive position D for the CVT automatic transmission mode, and a low-gear drive position L. The shift knob 138 can also be brought from the drive position D into a manual transmission mode position M.
When the shift knob 138 is in the drive position D (CVT automatic transmission mode position), the CVT has its transmission gear ratio automatically variable continuously depending on the running state of the vehicle. When the shift knob 138 is in the manual transmission mode position M, the shift knob 138 can be manually moved in the positive or negative direction to change the transmission gear ratio through seven steps. The shifter 112 supplies a signal representing the manual transmission mode as the manual transmission mode signal Sm (which is turned on when the shift knob 138 is in the manual transmission mode position M and turned off in the other positions) to the weighting variable calculator 110A.
The noise/vibration/sound control ECU 100A according to the second embodiment operates as follows: In the automatic transmission mode when the manual transmission mode signal Sm is turned off, as can be seen from the weighing variable map MP3a that is applicable in the automatic transmission mode as shown in
In the manual transmission mode when the manual transmission mode signal Sm is turned on, as can be seen from the weighing variable map MP3m, as the engine rotation frequency fe increases from a low range to a high range and the frequency change Δaf increases from a low range to a high range, the weighting variable W3m gradually increases to operate the ASC 60. Since the ASC 60 is controlled to operate in almost all ranges except for an idling range, a sound effect is generated to give the driver or a passenger sporty feeling while driving the vehicle 102.
The present invention is not limited to the above embodiments. If the engine 12 is an engine having cylinders that can selectively be disabled, then the maps MP1, MP2, MP3, MP3a, MP3m may be changed to activate and inactivate the AVC 50, the ANC 16, the ASC 60 based on a cylinder disabling signal. Rotation pulses from the propeller shaft, rather than the engine rotation pulses Ep, may be used as the detected signal of vibrations of the engine.
Although certain preferred embodiments of the present invention have been shown and described in detail, it should be understood that various changes and modifications may be made therein without departing from the scope of the appended claims.
Number | Date | Country | Kind |
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2005-157662 | May 2005 | JP | national |
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09-060515 | Mar 1997 | JP |
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Number | Date | Country | |
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20060269078 A1 | Nov 2006 | US |