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Title:
ACTIVE NOISE CANCELLATION SYSTEM FOR REDUCING NOISE GENERATED BY CLIMATE CONTROL SYSTEM
Document Type and Number:
WIPO Patent Application WO/2019/152241
Kind Code:
A1
Abstract:
A noise cancellation system for a vehicle includes a climate control system including one or more components that generate noise inside the vehicle during operation. A noise frequency determination module is configured to identify N noise frequencies generated by the one or more components, where N is an integer greater than zero. An audio system includes a microphone to measure noise at the N noise frequencies and is configured to generate a noise cancellation signal based on the measured noise at the N frequencies to at least partially cancel the noise generated by the one or more components of the climate control system.

Inventors:
SCHUMACHER, Darren Andrew (4483 Links Court, Ann Arbor, Michigan, 48108, US)
IQBAL, Syed Rafat (645 International Avenue, LaSalle, Ontario N9J 0A5, 0A5, CA)
Application Number:
US2019/014779
Publication Date:
August 08, 2019
Filing Date:
January 23, 2019
Export Citation:
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Assignee:
GENTHERM INC. (21680 Haggerty Road, Northville, Michigan, 48167, US)
International Classes:
G10K11/178
Domestic Patent References:
WO2017064603A12017-04-20
Foreign References:
DE102016005876A12017-11-16
US20100172511A12010-07-08
DE102014002554A12015-08-27
FR2996342A12014-04-04
JPH01186419A1989-07-25
US20170330551A12017-11-16
EP3130897A12017-02-15
Attorney, Agent or Firm:
WIGGINS, Michael D. (Harness, Dickey & Pierce P.L.C.,P.O. Box 82, Bloomfield Hills Michigan, 48303, US)
Download PDF:
Claims:
CLAIMS

What is claimed is:

1. A noise cancellation system for a vehicle, comprising:

a climate control system including one or more components that generate noise inside the vehicle during operation;

a noise frequency determination module configured to identify N noise frequencies generated by the one or more components, where N is an integer greater than zero; and

an audio system including a microphone to measure noise at the N noise frequencies and configured to generate a noise cancellation signal based on the measured noise at the N frequencies to at least partially cancel the noise generated by the one or more components of the climate control system.

2. The noise cancellation system of claim 1 , wherein the audio system further comprises speakers to output the noise cancellation signal.

3. The noise cancellation system of claim 1 , wherein the one or more components are selected from a group consisting of a fan motor and a compressor.

4. The noise cancellation system of claim 1 , wherein the climate control system includes the noise frequency determination module.

5. The noise cancellation system of claim 1 , wherein the audio system includes the noise frequency determination module.

6. The noise cancellation system of claim 1 , wherein the audio system is configured to generate the noise cancellation signals in response to changes in an operating state of the one or more components of the climate control system.

7. The noise cancellation system of claim 1 , wherein the audio system is configured to generate the noise cancellation signals in response to changes in an operating state of the climate control system.

8. The noise cancellation system of claim 7, wherein the noise frequency determination module is configured to wait a predetermined period after the climate control system changes the operating state to perform noise cancellation.

9. The noise cancellation system of claim 2, wherein the noise frequency determination module is configured to:

a) monitor control signals to the one or more components; and

b) identify the N noise frequencies for the one or more components based on the control signals.

10. The noise cancellation system of claim 1 , wherein the noise determination module is configured to:

a) monitor control signals to the one or more components;

b) identify the N noise frequencies based on the control signals;

c) monitor noise levels at the N noise frequencies using the microphone; and d) selectively perform noise cancellation at selected ones of the N noise frequencies if measured noise levels at the N noise frequencies are greater than corresponding ones of N predetermined noise thresholds, respectively.

1 1. The noise cancellation system of claim 10, wherein the noise determination module is configured to:

e) monitor noise levels in a predetermined range around other ones of the N noise frequencies; and

f) selectively perform noise cancellation if measured noise levels in the predetermined range around the other ones of the N noise frequencies are greater than corresponding ones of the N predetermined noise thresholds, respectively.

12. A noise cancellation system for a vehicle, comprising:

a climate control system to generate control signals to control one or more components thereof based on a desired operating state of the climate control system, wherein the one or more components generate noise inside of the vehicle during operation; and

a noise cancellation module configured to: determine first estimated noise signals produced by the one or more components when operating in the desired operating state;

determine second estimated noise signals produced by the one or more components when operating in an adjacent operating state that is adjacent to the desired operating state; and

select one of the desired operating state and the adjacent operating state for operating the climate control system based on the first estimated noise signals, the second estimated noise signals and noise criteria.

13. The noise cancellation system of claim 12, wherein the climate control system operates in the selected one of the desired operating state and the adjacent operating state.

14. The noise cancellation system of claim 13, further comprising an audio system to generate a noise cancellation signal to cancel the noise signals generated by the one or more components of the climate control system when the climate control system is operated in the selected one of the desired operating state and the adjacent operating state.

15. The noise cancellation system of claim 12, wherein the noise cancellation module selects the desired operating state when noise at N noise frequencies of the first estimated noise signal are less than N thresholds, respectively.

16. The noise cancellation system of claim 15, wherein the noise cancellation module selects the adjacent operating state when noise at at least one of the N noise frequencies of the second estimated noise signal is greater than the N thresholds.

17. The noise cancellation system of claim 12, wherein the noise cancellation module determines the first estimated noise signals and the second estimated noise signals using at least one of a model, a synthesizer, a lookup table and a formula.

18. The noise cancellation system of claim 12, wherein the noise cancellation module determines the first estimated noise signals and the second estimated noise signals by operating in the desired operating state and the adjacent operating state and measuring noise signals at N noise frequencies.

19. The noise cancellation system of claim 12, wherein the noise cancellation module includes:

one or more noise synthesizers to synthesize noise output by the one or more components, respectively, based on control signals output to the one or more components;

a summer configured to sum outputs of the one or more noise synthesizers; and

N filters configured to filter an output of the summer;

N comparators configured to compare outputs of the N filters to N thresholds, respectively; and

an operating condition selector configured to select one of the desired operating state and the adjacent operating state based on outputs of the N comparators.

20. The noise cancellation system of claim 12, wherein the noise cancellation module includes:

one or more lookup tables to estimate noise output by the one or more components, respectively, based on control signals output to the one or more components;

a combiner configured to combine outputs of the one or more lookup tables; a frequency range analyzer configured to receive and analyze an output of the combiner at N noise frequencies using N noise thresholds, respectively; and

an operating condition selector configured to select one of the desired operating state and the adjacent operating state based on an output of the frequency range analyzer.

Description:
ACTIVE NOISE CANCELLATION SYSTEM FOR REDUCING NOISE GENERATED

BY CLIMATE CONTROL SYSTEM

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Patent Application Serial No. 62/625,681 , filed on February 2, 2018, which is hereby incorporated by reference in its entirety.

FIELD

[0002] The present disclosure relates to active noise cancellation systems, and more particularly to active noise cancellation systems for reducing noise generated by a climate control system.

BACKGROUND

[0003] The background description provided here is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.

[0004] As a vehicle travels at speed, road noise is generated by wind hitting the vehicle, tire contact with road surfaces, engine and transmission noise, brake noise, and/or other noise sources. For some drivers, road noise is an enjoyable part of the driving experience. For other drivers, however, road noise is annoying. Road noise may make it difficult to have a conversation in the vehicle and/or to listen to music.

[0005] Noise cancelling systems typically include one or microphones that are arranged in the interior of the vehicle. The microphones are used to identify different sources of road noise. The noise cancelling system generates audio signals that destructively interfere with the noise (e.g. they are 180-degrees out of phase with the noise) to cancel the noise and create a quieter environment.

SUMMARY

[0006] A noise cancellation system for a vehicle includes a climate control system including one or more components that generate noise inside the vehicle during operation. A noise frequency determination module is configured to identify N noise frequencies generated by the one or more components, where N is an integer greater than zero. An audio system includes a microphone to measure noise at the N noise frequencies and is configured to generate a noise cancellation signal based on the measured noise at the N frequencies to at least partially cancel the noise generated by the one or more components of the climate control system.

[0007] In other features, the audio system further comprises speakers to output the noise cancellation signal. The one or more components are selected from a group consisting of a fan motor and a compressor. The climate control system includes the noise frequency determination module. The audio system includes the noise frequency determination module.

[0008] In other features, the audio system is configured to generate the noise cancellation signals in response to changes in an operating state of the one or more components of the climate control system. The audio system is configured to generate the noise cancellation signals in response to changes in an operating state of the climate control system. The noise frequency determination module is configured to wait a predetermined period after the climate control system changes the operating state to perform noise cancellation.

[0009] In other features, the noise frequency determination module is configured to monitor control signals to the one or more components and identify the N noise frequencies for the one or more components based on the control signals.

[0010] In other features, the noise determination module is configured to monitor control signals to the one or more components, identify the N noise frequencies based on the control signals, monitor noise levels at the N noise frequencies using the microphone, and selectively perform noise cancellation at selected ones of the N noise frequencies if measured noise levels at the N noise frequencies are greater than corresponding ones of N predetermined noise thresholds, respectively.

[0011] In other features, the noise determination module is configured to monitor noise levels in a predetermined range around other ones of the N noise frequencies, and selectively perform noise cancellation if measured noise levels in the predetermined range around the other ones of the N noise frequencies are greater than corresponding ones of the N predetermined noise thresholds, respectively.

[0012] A noise cancellation system for a vehicle includes a climate control system to generate control signals to control one or more components thereof based on a desired operating state of the climate control system. The one or more components generate noise inside of the vehicle during operation. A noise cancellation module is configured to determine first estimated noise signals produced by the one or more components when operating in the desired operating state; determine second estimated noise signals produced by the one or more components when operating in an adjacent operating state that is adjacent to the desired operating state; and select one of the desired operating state and the adjacent operating state for operating the climate control system based on the first estimated noise signals, the second estimated noise signals and noise criteria.

[0013] In other features, the climate control system operates in the selected one of the desired operating state and the adjacent operating state. An audio system generates a noise cancellation signal to cancel the noise signals generated by the one or more components of the climate control system when the climate control system is operated in the selected one of the desired operating state and the adjacent operating state.

[0014] In other features, the noise cancellation module selects the desired operating state when noise at N noise frequencies of the first estimated noise signal are less than N thresholds, respectively. The noise cancellation module selects the adjacent operating state when noise at at least one of the N noise frequencies of the second estimated noise signal is greater than the N thresholds.

[0015] In other features, the noise cancellation module generates the first estimated noise signals and the second estimated noise signals using at least one of a model, a synthesizer, a lookup table and a formula. The noise cancellation module determines the first estimated noise signals and the second estimated noise signals by operating in the desired operating state and the adjacent operating state and measuring noise signals at N noise frequencies.

[0016] In other features, the noise cancellation module includes one or more noise synthesizers to synthesize noise output by the one or more components, respectively, based on control signals output to the one or more components. A summer is configured to sum outputs of the one or more noise synthesizers. N filters are configured to filter an output of the summer. N comparators are configured to compare outputs of the N filters to N thresholds, respectively. An operating condition selector is configured to select one of the desired operating state and the adjacent operating state based on outputs of the N comparators.

[0017] In other features, the noise cancellation module includes one or more lookup tables to estimate noise output by the one or more components, respectively, based on control signals output to the one or more components. A combiner is configured to combine outputs of the one or more lookup tables. A frequency range analyzer is configured to receive and analyze an output of the combiner at N noise frequencies using N noise thresholds, respectively. An operating condition selector is configured to select one of the desired operating state and the adjacent operating state based on an output of the frequency range analyzer.

[0018] A method cancels noise generated by one or more components of a climate control system in a vehicle. The method includes identifying N noise frequencies generated by the one or more components, where N is an integer greater than zero. The method includes measuring noise at the N noise frequencies and generating a noise cancellation signal based on the measured noise at the N frequencies to at least partially cancel the noise generated by the one or more components of the climate control system.

[0019] In other features, the method includes using speakers to output the noise cancellation signal. The one or more components are selected from a group consisting of a fan motor and a compressor.

[0020] In other features, the method includes generating the noise cancellation signals in response to changes in an operating state of the one or more components of the climate control system. The method includes waiting a predetermined period after the climate control system changes the operating state to perform noise cancellation.

[0021] In other features, the method includes monitoring control signals to the one or more components and identifying the N noise frequencies for the one or more components based on the control signals.

[0022] In other features, the method includes monitoring control signals to the one or more components, identifying the N noise frequencies based on the control signals, monitoring noise levels at the N noise frequencies using the microphone, and selectively performing noise cancellation at selected ones of the N noise frequencies if measured noise levels at the N noise frequencies are greater than corresponding ones of N predetermined noise thresholds, respectively.

[0023] In other features, the method includes monitoring noise levels in a predetermined range around other ones of the N noise frequencies, and selectively performing noise cancellation if measured noise levels in the predetermined range around the other ones of the N noise frequencies are greater than corresponding ones of the N predetermined noise thresholds, respectively. [0024] A method cancels noise of one or more components of a climate control system inside a vehicle. The method includes generating control signals to control one or more components of the climate control system based on a desired operating state of the climate control system. The method includes determining first estimated noise signals produced by the one or more components when operating in the desired operating state; determining second estimated noise signals produced by the one or more components when operating in an adjacent operating state that is adjacent to the desired operating state; and selecting one of the desired operating state and the adjacent operating state for operating the climate control system based on the first estimated noise signals, the second estimated noise signals and noise criteria.

[0025] In other features, the method includes operating in the selected one of the desired operating state and the adjacent operating state. The method includes generating a noise cancellation signal to cancel the noise signals generated by the one or more components of the climate control system when the climate control system is operated in the selected one of the desired operating state and the adjacent operating state.

[0026] In other features, the method includes selecting the desired operating state when noise at N noise frequencies of the first estimated noise signal are less than N thresholds, respectively. The method includes selecting the adjacent operating state when noise at at least one of the N noise frequencies of the second estimated noise signal is greater than the N thresholds.

[0027] In other features, the method includes determining the first estimated noise signals and the second estimated noise signals using at least one of a model, a synthesizer, a lookup table and a formula. The method includes determining the first estimated noise signals and the second estimated noise signals by operating in the desired operating state and the adjacent operating state, respectively, and measuring noise signals at N noise frequencies.

[0028] In other features, the method includes synthesizing noise output by the one or more components, respectively, based on control signals output to the one or more components. The method generating a summed outputs from the one or more noise synthesizers. The method includes filtering the summed output using N filters. The method includes comparing outputs of the N filters to N thresholds, respectively. The method includes selecting one of the desired operating state and the adjacent operating state based on outputs of the N comparators. [0029] In other features, the method includes estimating noise output by the one or more components, respectively, using one or more lookup table indexed by control signals output to the one or more components. The method includes combining outputs of the one or more lookup tables into a combined output. The method includes analyzing the combined output at N noise frequencies using N noise thresholds. The method includes selecting one of the desired operating state and the adjacent operating state based on the analyzing.

[0030] Further areas of applicability of the present disclosure will become apparent from the detailed description, the claims and the drawings. The detailed description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The present disclosure will become more fully understood from the detailed description and the accompanying drawings, wherein:

[0032] FIG. 1 is a functional block diagram of an example of an environment including an audio system with noise cancellation and a climate control system according to the present disclosure;

[0033] FIGs. 2-5 are flowcharts of examples of methods for controlling the audio system to perform noise cancellation for noise generated by climate control system components according to the present disclosure;

[0034] FIG. 6 is a functional block diagram of an example of an audio system with a noise synthesizer and operating condition selector according to the present disclosure;

[0035] FIG. 7 is a functional block diagram of another example of an audio system with a noise analyzer and operating condition selector according to the present disclosure; and

[0036] FIGs. 8-9 are flowcharts of examples of methods for controlling the audio system to perform noise cancellation for noise generated by climate control system components according to the present disclosure.

[0037] In the drawings, reference numbers may be reused to identify similar and/or identical elements. DETAILED DESCRIPTION

[0038] Noise canceling systems and methods according to the present disclosure may be used to further enhance the operation of audio systems with noise cancellation. The noise canceling systems disclosed herein address noise generated during operation of climate control systems associated with cabin or space air conditioning systems and climate seat conditioning systems. The noise canceling systems disclosed herein reduce (or eliminate) the number of noise sensors required for the cancellation of noise generated by these conditioning systems.

[0039] Climate control systems such as heating, ventilation and air conditioning (HVAC) systems or climate controlled seats typically include one or more fans, compressors or other components. The climate control systems generate component control signals to control the one or more fans, compressors, and/or other components. For example, digital control signals and/or analog control signals (such as voltage signals or pulse width modulated (PWM) signals) are output to achieve a desired fan speed, compressor speed or other operating condition.

[0040] The climate control system includes a climate controller that identifies one or more expected noise frequencies of one or more components based upon the component control signals. In some examples, the expected noise frequencies are determined based on the voltage (or PWM) signal, the operating speed of the component and/or other parameters. In some examples, the climate controller outputs the expected noise frequencies to the noise cancellation system of the audio system to allow additional noise reduction.

[0041] During development of the climate control system, noise testing is performed to identify the expected noise frequencies during operation of the components when driven by the component control signals. Because some components like fan motors emit noise at one or more frequencies when operating at a given speed, the noise cancellation system applies signal processing techniques to identify the fan noise and to adjust the noise cancellation accordingly.

[0042] When the climate control system is adjusted by a vehicle occupant, the component control signals change. In other words, the control signals for the components vary based on the new operating condition or state. The component control signals are monitored. The component control signals are used to access one or more lookup tables or as inputs to functions or models. In some examples, a voltage control signal output to the component is used to access the lookup table. The lookup table generates one or more expected noise frequencies based on the one or more component control signals. In some examples, interpolation may be used to determine interpolated values between values stored in the lookup table. In still other examples, a model or function can be used to relate the component control signals to the one or more expected noise frequencies.

[0043] The one or more expected noise frequencies are output to the noise cancellation module associated with the audio system. The noise cancellation system generates audible output signals at the one or more expected noise frequencies that destructively interfere with the noise signals produced by the components.

[0044] If no noise is actually present at the expected frequencies, the noise cancellation system may inadvertently add noise to the environment. In some examples, to avoid adding noise to the environment, the noise cancellation system attempts to detect noise at the one or more expected noise frequencies using the microphones. Then, the noise canceling system generates the output signals to destructively interfere with the noise only if noise is detected at the one or more expected noise frequencies.

[0045] Operation of the components may change over time. As a result, the noise profile of the component may also change. In some examples, if no noise is found at some of the expected noise frequencies, the noise canceling system searches adjacent frequency bands and cancels the noise at newly identified frequencies. The models, lookup tables and/or equations may also be modified for the subsequent use. The adaptation makes the noise canceling system more robust to variations due to manufacturing or longevity-based variability.

[0046] It may be desirable to let the occupants know that noise cancellation is occurring. In some examples, the noise canceling system provides audible feedback to the passenger to identify that the noise cancelling system was turned on. For example, the noise canceling system may be initiated a predetermined period after the climate control system is turned on or transitions to a new operating state (and the component noise is generated) so that the component noise can be heard briefly prior to noise cancellation.

[0047] In some examples, noise levels at the expected noise frequencies are actively managed to one or more predetermined noise levels, respectively, above background ambient noise levels. Alternatively, the noise quality can be analyzed and altered to make it less objectionable (e.g. incomplete destructive interference may be used). [0048] Referring now to FIG. 1 , an environment 100 (such as a room or vehicle) includes an audio system 1 10. The audio system 110 includes an audio system control module 1 12 and a noise canceling module 1 14. The audio system control module 1 12 controls operation of the audio system 1 10 based upon user inputs to a user interface (not shown). For example, the audio system control module 1 12 receives a desired volume level, media selection, and/or other audio control parameters via the user interface and outputs audio signals to one or more speakers 1 16 located in the environment. In some examples, the noise canceling module 1 14 may synthesize and output noise canceling audio signals to the speakers 1 16. In other examples, the noise canceling module 1 14 outputs the noise canceling audio signals to speakers dedicated to noise cancellation.

[0049] The noise canceling module 1 14 receives inputs from one or more noise canceling microphones 1 18. The one or more noise canceling microphones 1 18 are arranged in the environment and are used to measure ambient noise levels and/or noise levels at one or more specific frequencies. In some examples, one or more noise canceling error microphones 122 may optionally be used to detect noise canceling errors such as incomplete destructive interference. In some examples, one or more accelerometers 124 may be used to detect vibration to facilitate detection of road noise.

[0050] Examples of suitable noise canceling systems are described in US. Patent Publication No. 2017/0330551 , European Patent Application No. 3 130 897, and PCT Publication No. 2017/064603, which are hereby incorporated herein by reference in their entirety.

[0051] The environment 100 further includes a climate control system 130 including a climate controller 134. The climate controller 134 includes a noise frequency module 136 and a climate control module 138. The noise frequency module 136 identifies one or more noise frequencies for the components based upon a current operating state or a desired operating state. While the noise frequency module 136 is shown as part of the climate controller 134, the noise frequency module 136 can also be a part of the audio system and receive either climate control operating state information or control signals from the climate controller 134 or a vehicle bus.

[0052] The climate controller 134 further includes a fan motor driver 140 that generates component control signals to control speeds of one or more fan motors 148. A compressor motor driver 142 generates component control signals that are output to one or more compressors 150. In some examples, the component control signals are voltage signals or pulse width modulated (PWM) signals. The climate control system 130 may further include sensors for monitoring operational parameters of the various components (e g. component speed, temperature, pressure), and that generate signals or sensor inputs 144 indicative of the measured parameters. Operation of the climate control system 130 may be controlled by an operator interface 146.

[0053] The noise frequency module 136 monitors the component control signals that are used to control the one or more fan motors 148 and/or the one or more compressors 150. The noise frequency module 136 outputs one or more expected noise frequencies for the one or more components based upon the component control signals that are output to the one or more components.

[0054] In some examples, the noise frequency module 136 outputs the one or more expected noise frequencies that are expected using a lookup table that is indexed by the component control signals for the components. In some examples, interpolation can be performed by the noise frequency module 136 between lookup table values. In other examples, the noise frequency module 136 uses a model or function to determine the one or more expected noise frequencies for the one or more components based upon the component control signals output to the one or more components.

[0055] In some examples, noise cancellation is enabled after the ambient noise level in the environment exceeds a predetermined ambient noise level. In some examples, an ambient noise threshold can be varied based upon the speed of the vehicle. For example, noise cancellation may be enabled at different ambient noise levels since the ambient noise levels in the environment at 100 km/hour is significantly higher than ambient noise levels in the environment at 30 km/hour or in a stationary vehicle.

[0056] In some examples, noise cancellation may be performed on selected ones of the expected noise frequencies and not all of the expected noise frequencies. For example, specific frequencies and/or amplitudes may be more irritating to passengers than other noise frequencies and/or amplitudes. For example, noise cancellation may be used for a fan blade pass frequency and not used for other expected noise frequencies of the component.

[0057] In other examples, noise cancellation may be performed on frequencies or tones in the audible frequency range that are above the ambient noise level by a predetermined noise level such as 7dB.

[0058] Referring now to FIG. 2, a method 200 for controlling the noise canceling system is shown. At 210, the method determines whether the climate central system is activated. If 210 is true, the method monitors the output signals to the components. At 214, the method determines one or more noise frequencies where noise is expected when operating the components based on the component control signals. At 218, the one or more expected noise frequencies are output to a noise canceling system. At 220, noise cancellation is performed at some or all of the one or more expected noise frequencies.

[0059] Referring now to FIG. 3, a method 230 for controlling the noise canceling system is shown. At 210, the method determines whether the climate system is activated. Prior to initiating noise cancellation, the method determines at 232 whether the ambient noise is greater than one or more ambient noise thresholds NTH. If 232 is true, the method monitors the output signals to the components. At 214, the method determines one or more noise frequencies where noise is expected when operating the components based on the output signal. At 218, the one or more expected noise frequencies are output to a noise cancellation module. At 220, noise cancellation is performed based upon the one or more expected noise frequencies.

[0060] Referring now to FIG. 4, a method 300 for controlling the noise canceling system is shown. At 310, the method determines whether the climate control system is activated. If 310 is true, the method monitors the output signals to the components. At 314, the method determines one or more noise frequencies where noise is expected for the components based on the component control signals. At 318, the one or more expected noise frequencies are output to a noise cancellation module. At 328, the noise cancellation module measures noise at the expected noise frequencies using one or more noise canceling microphones. At 332, the method determines whether noise is detected at the frequencies that were identified for the climate control system components. If 332 is true, the method performs noise cancellation at the one or more expected noise frequencies. If 332 is false, the noise canceling system searches for noise at other frequencies that are identified based on the one or more expected noise frequencies using the microphones at 344. For example, the noise canceling system may search within a predetermined frequency range of the one or more expected noise frequencies. In some examples, the predetermined frequency range is +/- 100 Hz, +/- 200 Hz or +/- 400 Hz of the expected noise frequency.

[0061] If noise is detected for the climate control system component as determined at 348, noise cancellation is performed at one or more new noise frequencies where the noise is found at 352. At 354, the modules, lookup tables or equations relating the control signal to the expected noise frequencies are adjusted based on the new noise frequencies.

[0062] Referring now to FIG. 5, a method 400 for controlling the noise canceling system is shown. At 410, one of the one or more frequencies in the audible frequency range is selected. At 414, the method determines whether the noise at the selected frequency is greater than ambient noise. For example, the method may determine whether the noise at the selected frequency is greater than the ambient noise plus a noise threshold NTH2. If 414 is true, the method uses noise cancellation at the selected frequency at 418. If 414 is false, the method continues at 422 and determines whether other noise frequencies have been identified. If 422 is true, the method selects another one of the one or more frequencies in the audible frequency range at 424 and returns to 414.

[0063] In other examples, the climate control system generates or synthesizes a composite noise signal. Referring now to FIG. 6, a portion of a noise cancellation module 460 includes a noise analyzer 468 and an operating condition selector 464. The operating condition selector 464 receives a desired operating condition as an input. The operating condition selector 464 determines whether or not to operate at the desired operating condition or an adjacent operating condition after analyzing the noise levels in various ways described further below. In some examples, the adjacent operating condition may include a different fan speed (such as fan speeds above or below a fan speed corresponding to the desired operating condition), a different temperature setpoint (such as one or more degrees above or below the desired setpoint) or other adjacent operating conditions.

[0064] The noise analyzer 468 includes one or more component noise synthesizers 472-1 , 472-2, and 472-C (collectively, component noise synthesizers 472), where C is an integer. The component noise synthesizers 472 synthesize noise outputs of corresponding components based upon an operating condition or state that is input to the component noise synthesizer 472 by the operating condition selector 464. In some examples, the component noise synthesizers 472 include noise models of the corresponding components. For example, each of the component noise synthesizers 472 correspond to one or more vehicle components that generate noise during operation. The component noise synthesizers 472 generate noise signals representing expected noise generated by the component at the operating condition or state. [0065] In some examples, the component noise synthesizers 472 receive the operating condition or state for the respective component. For example, the component may correspond to a seat ventilation fan, the operating condition may correspond to ON HIGH, and the operating state may correspond to operation of the fan at 320 rpm. The component noise synthesizer 472 for the seat ventilating fan generates a noise signal including noise levels in different frequency ranges when the seat ventilating fan is operated at 320 rpm. A similar approach may be used for other components.

[0066] In some examples, the component noise synthesizers 472 use a function or a numerical model that models or estimates noise output by the component as a function of the operating condition or operating state (e.g. Component Noise = ^Operating state)). In other examples, the function or a numerical model is also a function of other conditions such as component age, ambient temperature, vehicle speed, engine speed, etc. In other examples, the component noise synthesizers 472 store representations of stored noise signals as a function of frequency for each operating condition. The stored noise signals may be sampled in the vehicle or in a controlled environment.

[0067] Since the vehicle may include multiple components that are changing operating conditions or states and each of the components may generate noise in various frequency ranges (that may or may not overlap with noise output by other components), the noise signals of the components are summed. For example, outputs of the component noise synthesizers 472 are input to a summer 474 to create a composite noise signal.

[0068] The composite noise signal output by the summer 474 is input to filters 476-1 , 476-2, ... , and 476-N (collectively filters 476) (where N is an integer greater than one) that pass different frequency ranges. Generally, analysis will occur in an audible frequency range since operation outside of the audible frequency range is generally not important to interior noise levels. For example only, each of the filters 476 may include a band pass filter or a combination of a low pass filter and a high pass filter for a particular frequency range of interest. Each of the filters 476 passes a different frequency range. Flowever, the frequency ranges of the filters 476 can be partially overlapping, adjacent or non-overlapping.

[0069] Outputs of the filters 476 are input to comparators 480-1 , 480-2, ... , and 480-N (collectively comparators 480). The comparators 480 also receive signal noise thresholds THi , TH2, ... , and TFIN, which can be the same for each frequency range or different. In some examples, the thresholds set peak noise levels across each frequency range, average noise levels for the frequency range and/or peak noise levels for the frequency ranges. However, more complex analysis may be performed.

[0070] In addition, the signal noise thresholds THi , TH2, ... , and THN can be modified or varied as a function of the mode of operation of the vehicle or ambient interior noise levels. For example, the signal noise thresholds can be changed for different driving modes such as idle operation, startup, city driving, highway driving, etc. or based on sensed ambient noise levels in the vehicle. In other words, more aggressive noise cancelling may be performed for lower ambient noise levels associated with idle operation as compared to highway speeds.

[0071] Outputs of the comparators 480 are input to the operating condition selector 464. The operating condition selector 464 receives a desired operating condition as an input. The operating condition selector 464 outputs the operating condition or states corresponding to the desired operating condition to each of the component noise synthesizers 472. The operating condition selector 464 receives results from the comparators 480. The operating condition selector 464 uses the results from the comparators and selection criteria to determine whether or not to use the desired operating condition or to continue trying one or more adjacent operating conditions.

[0072] In some examples, the selected operating condition may be the same as the desired operating condition. Noise cancellation may be performed to further reduce the noise generated by the desired operating condition. In other examples, the selected operating condition corresponds to an adjacent operating condition and is not the same as the desired operating condition. For example, when the noise levels for the desired operating condition do not meet the noise criteria, adjacent operating conditions may be evaluated and used if they meet the noise criteria. Noise cancellation may be performed to further reduce the noise generated by the adjacent operating condition as well.

[0073] In some examples, the noise criteria may include all of the components being below the corresponding signal noise or signal power thresholds. In some examples, the noise criteria may include G of N of the frequencies being below the corresponding signal noise or power thresholds (where G is an integer, G > 0 and G < N). In some examples, a weighted function is used to generate a score. Some of frequency ranges are weighted higher or lower than others of the frequency ranges. While examples of criteria are described, other criteria may be used. In other examples, the results of the comparisons are stored, one or more adjacent operating conditions are evaluated (and results are stored) and then an operating condition corresponding to a lowest noise or highest or lowest score is selected.

[0074] Referring now to FIG. 7, an audio system control module 484 includes a noise analyzer 486 and an operating condition selector 464. Rather than synthesizing the expected noise, lookup tables may be used. The noise analyzer 486 includes one or more component lookup tables (LUT) 492-1 , 492-2, and 492-C (collectively, component LUTs 492), where C is an integer. The component LUTs 492 store noise information based upon an operating condition or state that is input to the component LUT 492. Each of the component LUTs 492 includes a table of values representing expected operating noise values at different frequencies that will be generated by the component at the operating condition or state. The component LUTs 492 output frequency range and noise level pairs. A similar approach may be used for other components.

[0075] Since the vehicle may include multiple components that are changing state and each of the components may generate noise in overlapping frequency ranges, the frequency range and noise level pairs of the components are combined in combiner 494. In other words, outputs of the component LUTs 492 are input to the combiner 494 to create composite noise value pairs including noise values at different frequencies for all of the components. In some examples, the noise levels of the components are summed in each of the frequency ranges.

[0076] The frequency range analyzer 496 receives the summed noise levels for each of the frequency ranges of interest. The frequency range analyzer 496 compares the summed noise levels at each of the frequency ranges to corresponding thresholds and outputs results of the comparisons to the operating condition selector 464.

[0077] The operating condition selector 464 outputs the operating condition to the component LUTs 492 and receives results from the frequency range analyzer 496. The operating condition selector 464 uses the results from the frequency range analyzer 496 and selection criteria to determine the selected operating condition. In some examples, the selected operating condition is the same as the desired operating condition. In other examples, the selected operating condition is not the same as the desired operating condition. For example, when the noise levels for the selected operating condition do not meet noise criteria, adjacent operating conditions may be evaluated and used if they meet the noise criteria. After the operating condition is selected, noise cancellation is performed. [0078] A similar result can be achieved by operating at the desired operating state and the adjacent operating state, measuring noise at the N frequencies at each mode and selecting one based on the measured noise at the N frequencies.

[0079] Referring now to FIG. 8, a method 500 is shown. At 510, the method determines whether there has been a requested change to a desired operating condition or state. At 514, the method determines the expected noise frequencies and noise levels of vehicle components at the desired operating state. As described above, the expected noise frequencies and noise levels can be determined using synthesizers, modeling, lookup tables or other methods. At 518, if the expected noise levels in the frequency ranges meet the predetermined criteria, the method continues at 522 and the vehicle transitions to the desired operating state.

[0080] If 518 is false and the expected noise levels of the frequency ranges do not meet the predetermined criteria, the method continues at 526 and identifies one or more adjacent operating states near the desired operating state. At 530, the method determines expected noise frequencies and noise levels of components at one of the adjacent operating states. At 534, the method determines whether the expected noise levels at the frequency ranges of the adjacent operating state meet the criteria. If 534 is true, the method continues at 538 and transitions to the adjacent operating state. If 534 is false, the method continues at 542 and determines whether there are other adjacent operating states to be considered. If 542 is true, the method returns to 534. If 542 is false, the method transitions to the desired operating state at 546. In other words, when none of the adjacent operating states meet the criteria, the method selects the desired operating state rather than the adjacent operating states.

[0081] As was described above, an alternate mode of operation involves evaluating the desired operating state and one or more adjacent operating states and selecting the best one based on selection criteria.

[0082] Referring now to FIG. 9, a method 604 for operating the active noise cancellation system is shown. At 604, the method determines whether a change is requested to a desired operating state. If 604 is true, the method continues at 608 and changes to the desired operating state (or an adjacent operating state as described above) without noise cancellation. After waiting a predetermined period in 612, the method continues at 616 and applies noise cancellation as described herein. As can be appreciated, if the noise cancellation is too fast to respond, the operator of the vehicle will not appreciate that noise cancellation is being performed. For example, by allowing operation without noise cancellation for a predetermined period in a range followed by operation with noise cancellation, the operator of the vehicle will notice the noise condition improvement. In some examples, the predetermined period is sufficient to allow the operator to notice the noise and the noise reduction. In some examples, the predetermined period is in a range from 0.5s to 10s. In other examples, the predetermined period is in a range from 0.5s to 3s.

[0083] The foregoing description is merely illustrative in nature and is in no way intended to limit the disclosure, its application, or uses. The broad teachings of the disclosure can be implemented in a variety of forms. Therefore, while this disclosure includes particular examples, the true scope of the disclosure should not be so limited since other modifications will become apparent upon a study of the drawings, the specification, and the following claims. It should be understood that one or more steps within a method may be executed in different order (or concurrently) without altering the principles of the present disclosure. Further, although each of the embodiments is described above as having certain features, any one or more of those features described with respect to any embodiment of the disclosure can be implemented in and/or combined with features of any of the other embodiments, even if that combination is not explicitly described. In other words, the described embodiments are not mutually exclusive, and permutations of one or more embodiments with one another remain within the scope of this disclosure.

[0084] Spatial and functional relationships between elements (for example, between modules, circuit elements, semiconductor layers, etc.) are described using various terms, including“connected,”“activated,”“coupled,”“ad jacent,”“next to,”“on top of,” “above,”“below,” and“disposed.” Unless explicitly described as being“direct,” when a relationship between first and second elements is described in the above disclosure, that relationship can be a direct relationship where no other intervening elements are present between the first and second elements, but can also be an indirect relationship where one or more intervening elements are present (either spatially or functionally) between the first and second elements. As used herein, the phrase at least one of A, B, and C should be construed to mean a logical (A OR B OR C), using a non-exclusive logical OR, and should not be construed to mean“at least one of A, at least one of B, and at least one of C.”

[0085] In the figures, the direction of an arrow, as indicated by the arrowhead, generally demonstrates the flow of information (such as data or instructions) that is of interest to the illustration. For example, when element A and element B exchange a variety of information but information transmitted from element A to element B is relevant to the illustration, the arrow may point from element A to element B. This unidirectional arrow does not imply that no other information is transmitted from element B to element A. Further, for information sent from element A to element B, element B may send requests for, or receipt acknowledgements of, the information to element A.

[0086] In this application, including the definitions below, the term“module” or the term “controller” may be replaced with the term“circuit.” The term“module” may refer to, be part of, or include: an Application Specific Integrated Circuit (ASIC); a digital, analog, or mixed analog/digital discrete circuit; a digital, analog, or mixed analog/digital integrated circuit; a combinational logic circuit; a field programmable gate array (FPGA); a processor circuit (shared, dedicated, or group) that executes code; a memory circuit (shared, dedicated, or group) that stores code executed by the processor circuit; other suitable hardware components that provide the described functionality; or a combination of some or all of the above, such as in a system-on-chip.

[0087] The module may include one or more interface circuits. In some examples, the interface circuits may include wired or wireless interfaces that are connected to a local area network (LAN), the Internet, a wide area network (WAN), or combinations thereof. The functionality of any given module of the present disclosure may be distributed among multiple modules that are connected via interface circuits. For example, multiple modules may allow load balancing. In a further example, a server (also known as remote, or cloud) module may accomplish some functionality on behalf of a client module.

[0088] The term code, as used above, may include software, firmware, and/or microcode, and may refer to programs, routines, functions, classes, data structures, and/or objects. The term shared processor circuit encompasses a single processor circuit that executes some or all code from multiple modules. The term group processor circuit encompasses a processor circuit that, in combination with additional processor circuits, executes some or all code from one or more modules. References to multiple processor circuits encompass multiple processor circuits on discrete dies, multiple processor circuits on a single die, multiple cores of a single processor circuit, multiple threads of a single processor circuit, or a combination of the above. The term shared memory circuit encompasses a single memory circuit that stores some or all code from multiple modules. The term group memory circuit encompasses a memory circuit that, in combination with additional memories, stores some or all code from one or more modules.

[0089] The term memory circuit is a subset of the term computer-readable medium. The term computer-readable medium, as used herein, does not encompass transitory electrical or electromagnetic signals propagating through a medium (such as on a carrier wave); the term computer-readable medium may therefore be considered tangible and non-transitory. Non-limiting examples of a non-transitory, tangible computer-readable medium are nonvolatile memory circuits (such as a flash memory circuit, an erasable programmable read-only memory circuit, or a mask read-only memory circuit), volatile memory circuits (such as a static random access memory circuit or a dynamic random access memory circuit), magnetic storage media (such as an analog or digital magnetic tape or a hard disk drive), and optical storage media (such as a CD, a DVD, or a Blu-ray Disc).

[0090] The apparatuses and methods described in this application may be partially or fully implemented by a special purpose computer created by configuring a general purpose computer to execute one or more particular functions embodied in computer programs. The functional blocks, flowchart components, and other elements described above serve as software specifications, which can be translated into the computer programs by the routine work of a skilled technician or programmer.

[0091] The computer programs include processor-executable instructions that are stored on at least one non-transitory, tangible computer-readable medium. The computer programs may also include or rely on stored data. The computer programs may encompass a basic input/output system (BIOS) that interacts with hardware of the special purpose computer, device drivers that interact with particular devices of the special purpose computer, one or more operating systems, user applications, background services, background applications, etc.

[0092] The computer programs may include: (i) descriptive text to be parsed, such as HTML (hypertext markup language), XML (extensible markup language), or JSON (JavaScript Object Notation) (ii) assembly code, (iii) object code generated from source code by a compiler, (iv) source code for execution by an interpreter, (v) source code for compilation and execution by a just-in-time compiler, etc. As examples only, source code may be written using syntax from languages including C, C++, C#, Objective-C, Swift, Haskell, Go, SQL, R, Lisp, Java®, Fortran, Perl, Pascal, Curl, OCaml, Javascript®, HTML5 (Hypertext Markup Language 5th revision), Ada, ASP (Active Server Pages), PHP (PHP: Hypertext Preprocessor), Scala, Eiffel, Smalltalk, Erlang, Ruby, Flash®, Visual Basic®, Lua, MATLAB, SIMULINK, and Python®.