Driving mode optimization engine order cancellation

Abstract

To provide drive mode optimized engine order cancellation (EOC).SOLUTION: An EOC system 400 generates feed forward noise signals with a noise signal generator 408 based on RPM of an engine and another rotating shaft, and uses those signals and an adaptively configured W-filter 418 to reduce an in-cabin SPL by radiating anti-noise through a speaker 424. The EOC system includes a drive mode detector 462 for detecting different vehicle drive modes based on an analysis of signals indicative of a current vehicle driving mode. Upon detection, the EOC system adaptively adjusts various tuning parameters for an EOC algorithm based on the current vehicle drive mode, and based on which engine orders are dominant during that drive mode, selectively targets different sets of engine orders for noise cancellation according to the current vehicle drive mode.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Application No. 62 / 869,247, filed July 1, 2019, the disclosure of which is incorporated herein by reference in its entirety.

[0002] The present disclosure is directed to engine order cancellation and, more particularly, to optimizing engine order cancellation and corresponding tuning parameters based on detected vehicle operating modes. [Background technology]

[0003] Active noise control (ANC) systems use feed-forward and feedback structures to attenuate undesirable noises and adaptively eliminate them in listening environments such as vehicle cabins. ANC systems generally cancel or reduce unwanted noises by generating canceling sound waves to destructively interfere with the unwanted audible noise. Destructive interference occurs when an "anti-noise" that is approximately the same magnitude but opposite in phase to the noise combines to reduce the sound pressure level (SPL) at a location. In a vehicle cabin listening environment, potential sources of undesirable noise come from sounds radiated by the engine, interactions between the vehicle's tires and the road surface on which the vehicle is traveling, and / or vibrations of other parts of the vehicle. Thus, the unwanted noise changes with speed, road conditions, and vehicle operating conditions.

[0004] An Engine Order Cancellation (EOC) system is a specific ANC system implemented in vehicles to reduce the level of unwanted interior vehicle noise originating from narrow-band acoustic and vibration emissions from the vehicle's engine and exhaust system or other rotating drivetrain components. EOC systems generate feed-forward noise signals based on the engine or other rotating shaft angular velocity, such as revolutions per minute (RPM), and use those signals and an adaptively configured W filter to reduce the SPL inside the vehicle cabin by radiating anti-noise through speakers.

[0005] EOC systems are typically least mean square (LMS) adaptive feedforward systems that continuously adapt a W-filter based on both RPM input from a driveshaft mounted sensor and signals from microphones located at various locations inside the vehicle's cabin. When tuning an EOC system, engineers start with a single wide open throttle (WOT) data run. By examining the sound measured at the passenger's ear versus RPM, dominant engine orders are identified. For each engine order, a single value for each of the key EOC algorithm parameters is identified. These EOC algorithm parameters typically include step size, stability SPL threshold, leakage, gain, etc. Summary of the Invention [Means for solving the problem]

[0006] Various aspects of the disclosure relate to optimizing engine order cancellation (EOC) parameters in an EOC system based on a current vehicle operating mode. In one or more exemplary embodiments, a method is provided for dynamically adjusting an EOC system based on a vehicle operating mode. The method may include the following steps: storing in a memory a set of EOC adjustment parameters for each of a plurality of vehicle operating modes, each set of EOC adjustment parameters differing between the vehicle operating modes; applying a first set of EOC adjustment parameters corresponding to the current vehicle operating mode; receiving at least one signal indicative of a vehicle operating condition; detecting a change in the current vehicle operating mode based on the at least one signal; and applying a second set of EOC adjustment parameters in response to the change in the current vehicle operating mode.

[0007] Implementations may include one or more of the following features: Applying the first set of EOC adjustment parameters corresponding to the current vehicle operating mode may include selecting from a memory a first set of EOC adjustment parameters corresponding to the first vehicle operating mode when the first vehicle operating mode is the current vehicle operating mode, and utilizing the first set of EOC adjustment parameters. Additionally, applying the second set of EOC adjustment parameters in response to a change in the current vehicle operating mode may include selecting from a memory a second set of EOC adjustment parameters corresponding to the second vehicle operating mode in response to a change in the current vehicle operating mode from the first vehicle operating mode to the second vehicle operating mode, and utilizing the second set of EOC adjustment parameters during EOC when the current vehicle operating mode is the second vehicle operating mode.

[0008] The set of EOC adjustment parameters for each of the plurality of vehicle driving modes may include at least a step size, a leakage value, a gain applied to one of the anti-noise signal and the noise signal, or a sound pressure level threshold applied to the error signal. The signal indicative of the vehicle operating condition may indicate engagement of a cruise control. Alternatively, the signal indicative of the vehicle operating condition may indicate at least one of revolutions per minute (RPM), speed, and torque. Thus, detecting a change in the current vehicle driving mode based on the at least one signal may include determining a rate of change of at least one of the RPM, speed, and torque, and comparing the rate of change to one or more predetermined thresholds.

[0009] The plurality of vehicle operating modes may include at least a partially open throttle operating mode and a constant speed operating mode. The plurality of vehicle operating modes may further include a wide open throttle operating mode.

[0010] One or more additional embodiments of the present disclosure are directed to an engine order cancellation (EOC) system. The EOC system may include at least one controllable filter configured to generate an anti-noise signal based on an adaptive transfer characteristic and a noise signal received from a noise signal generator. The adaptive transfer characteristic of the at least one controllable filter may be characterized by a set of filter coefficients. The EOC system may further include an adaptive filter controller including a processor and memory programmed to store a set of EOC tuning parameters for each of a plurality of vehicle driving modes, each set of EOC tuning parameters varying between the vehicle driving modes, apply the set of EOC tuning parameters corresponding to a current vehicle driving mode, and adapt the set of filter coefficients based on a noise signal and an error signal received from a microphone located in the vehicle cabin. The EOC system may also include a driving mode detector in communication with at least the adaptive filter controller. The driving mode detector may include a processor and memory programmed to receive at least one signal indicative of a vehicle operating condition, analyze the at least one signal to determine a current vehicle driving mode, and send a driving mode signal indicative of the current vehicle driving mode to the adaptive filter controller.

[0011] Implementations may include one or more of the following features: The driving mode detector may transmit a driving mode signal in response to detecting a change in a current vehicle driving mode. The set of EOC adjustment parameters for each of the plurality of vehicle driving modes may include at least one of a step size and a leakage value. The plurality of vehicle driving modes may include at least a partial open throttle driving mode and a constant speed driving mode. The at least one signal indicative of a vehicle operating condition may be indicative of at least one of revolutions per minute (RPM), speed, and torque. The at least one signal indicative of a vehicle operating condition may be indicative of a transmission gear condition.

[0012] One or more additional embodiments of the present disclosure are directed to a method for dynamically targeting dominant engine orders for active noise cancellation in an engine order cancellation (EOC) system based on a vehicle operating mode. The method may include storing a set of dominant engine orders for each of a plurality of vehicle operating modes, where each set of dominant engine orders differs between the vehicle operating modes, receiving at least one signal indicative of a vehicle operating condition, detecting a current vehicle operating mode based on the at least one signal, selecting a set of dominant engine orders corresponding to the current vehicle operating mode, and applying noise cancellation to each engine order in the set of dominant engine orders corresponding to the current vehicle operating mode.

[0013] Implementations may include one or more of the following features. The method may further include selecting a different set of dominant engine orders in response to detecting a change in a current vehicle operating mode. Each of the plurality of vehicle operating modes may correspond to a different condition of the vehicle transmission. For example, the present application provides the following: (Item 1) 1. A method for dynamically adjusting an engine order cancellation (EOC) system based on a vehicle operating mode, comprising: storing in a memory a set of EOC adjustment parameters for each of a plurality of vehicle operating modes, each set of EOC adjustment parameters differing between the vehicle operating modes; applying a first set of EOC adjustment parameters corresponding to a current vehicle operating mode; receiving at least one signal indicative of a vehicle operating condition; detecting a change in the current vehicle operating mode based on the at least one signal; Applying a second set of EOC adjustment parameters in response to a change in the current vehicle operating mode. The above method. (Item 2) applying the first set of EOC adjustment parameters corresponding to the current vehicle operating mode; selecting from a memory the first set of EOC adjustment parameters corresponding to the first vehicle operating mode when the first vehicle operating mode is the current vehicle operating mode; Utilizing the first set of EOC adjustment parameters during EOC and applying the second set of EOC adjustment parameters in response to the change in a current vehicle operating mode; in response to the change in current vehicle operating mode from the first vehicle operating mode to a second vehicle operating mode, selecting from memory the second set of EOC adjustment parameters corresponding to the second vehicle operating mode; utilizing the second set of EOC adjustment parameters during EOC when the current vehicle operating mode is a second vehicle operating mode. The method according to the above item, comprising: (Item 3) 2. The method of claim 1, wherein the set of EOC adjustment parameters for each of the plurality of vehicle operating modes includes at least a step size. (Item 4) 2. The method of claim 1, wherein the set of EOC adjustment parameters for each of the plurality of vehicle operating modes includes at least a leakage value. (Item 5) 2. The method of claim 1, wherein the set of EOC adjustment parameters for each of the plurality of vehicle operating modes includes at least a gain applied to one of an anti-noise signal and a noise signal. (Item 6) 2. The method of claim 1, wherein the set of EOC adjustment parameters for each of the plurality of vehicle operating modes includes at least a sound pressure level threshold applied to an error signal. (Item 7) 13. The method of claim 1, wherein the at least one signal indicates engagement of cruise control. (Item 8) 13. The method of any one of the preceding claims, wherein the at least one signal is indicative of at least one of revolutions per minute (RPM), speed, and torque. (Item 9) detecting the change in the current vehicle operating mode based on the at least one signal; Determining a rate of change of at least one of an RPM, a speed, and a torque; Comparing said rate of change to one or more predetermined thresholds. The method according to any one of the preceding items, comprising: (Item 10) 2. The method of claim 1, wherein the plurality of vehicle operating modes includes at least a partial open throttle operating mode and a constant speed operating mode. (Item 11) 20. The method of claim 19, wherein the plurality of vehicle operating modes further includes a wide open throttle operating mode. (Item 12) 1. An engine order cancellation (EOC) system, comprising: at least one controllable filter configured to generate an anti-noise signal based on an adaptive transfer characteristic and a noise signal received from a noise signal generator, the adaptive transfer characteristic of the at least one controllable filter being characterized by a set of filter coefficients; 1. An adaptive filter controller, comprising: storing a set of EOC adjustment parameters for each of a plurality of vehicle operating modes, each set of EOC adjustment parameters varying between vehicle operating modes; Applying the set of EOC adjustment parameters corresponding to the current vehicle operating mode; Adapting the set of filter coefficients based on the noise signal and the error signal received from a microphone located in the passenger compartment of the vehicle. the adaptive filter controller including a processor and memory programmed to an operating mode detector in communication with at least the adaptive filter controller, receiving at least one signal indicative of a vehicle operating condition; analyzing the at least one signal to determine the current vehicle operating mode; transmitting a driving mode signal indicative of the current vehicle driving mode to the adaptive filter controller; the operating mode detector including a processor and memory programmed to The engine order cancellation (EOC) system comprises: (Item 13) The system of claim 1, wherein the driving mode detector transmits the driving mode signal in response to detecting a change in the current vehicle driving mode. (Item 14) 20. The system of claim 19, wherein the set of EOC adjustment parameters for each of the plurality of vehicle operating modes includes at least one of a step size and a leakage value. (Item 15) 20. The system of claim 19, wherein the plurality of vehicle operating modes includes at least a partial open throttle operating mode and a constant speed operating mode. (Item 16) 20. The system of claim 19, wherein the at least one signal indicative of a vehicle operating condition is indicative of at least one of revolutions per minute (RPM), speed, and torque. (Item 17) 2. The system of claim 1, wherein the at least one signal indicative of a vehicle operating condition is indicative of a transmission gear condition. (Item 18) 1. A method for dynamically targeting a dominant engine order for active noise cancellation in an engine order cancellation (EOC) system based on a vehicle operating mode, comprising: storing a set of dominant engine orders for each of a plurality of vehicle operating modes, each set of dominant engine orders differing between vehicle operating modes; receiving at least one signal indicative of a vehicle operating condition; detecting a current vehicle operating mode based on the at least one signal; selecting the set of dominant engine orders corresponding to the current vehicle operating mode; applying noise cancellation to each engine order of said set of dominant engine orders corresponding to said current vehicle operating mode; The above method. (Item 19) 7. The method of any one of the preceding claims, further comprising selecting a different set of dominant engine orders in response to detecting a change in the current vehicle operating mode. (Item 20) 13. The method of claim 1, wherein each of the plurality of vehicle operating modes corresponds to a different condition of a vehicle transmission. (Summary) An engine order cancellation (EOC) system generates feed-forward noise signals based on the RPM of the engine and other rotating shafts and uses those signals and an adaptively configured W filter to reduce SPL within the vehicle cabin by radiating anti-noise through a speaker. The EOC system may include a driving mode detector for detecting different vehicle driving modes based on an analysis of a signal indicative of the current vehicle driving mode. Upon detection, the EOC system may adaptively adjust various tuning parameters for an EOC algorithm based on the current vehicle driving mode. The EOC system may also selectively target different sets of engine orders for noise cancellation according to the current vehicle driving mode based on which engine orders are dominant during that driving mode. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a block diagram of a vehicle having an engine order cancellation (EOC) system in accordance with one or more embodiments of the present disclosure. [Diagram 2]2 is a detailed diagram of the noise signal generator shown in FIG. 1 in accordance with one or more embodiments of the present disclosure. [Diagram 3] 1 is an exemplary graph showing sound pressure level (SPL) versus engine order for several different vehicle operating modes. [Figure 4] FIG. 1 is a schematic block diagram illustrating an EOC system including an operating mode detector in accordance with one or more embodiments of the present disclosure. [Diagram 5] 1 is an exemplary flowchart illustrating a method for optimizing an EOC adjustment parameter based on a vehicle operating mode in accordance with one or more embodiments of the present disclosure. [Figure 6] 1 is an example table illustrating EOC adjustment parameters that may be applied for a given driving mode or driving scenario in accordance with one or more embodiments of the present disclosure. [Figure 7] 1 is an exemplary plot showing relative SPL versus engine order measured for a vehicle in two different driving modes. [Figure 8] 1 is an example table illustrating advantageous engine orders for a given operating mode or operating scenario that may be targeted for EOC in accordance with one or more embodiments of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Where necessary, detailed embodiments of the present invention are disclosed herein, but it should be understood that the disclosed embodiments are merely exemplary of the present invention, which may be embodied in various and alternative forms. The figures are not necessarily to scale, and some features may be exaggerated or minimized to show details of specific components. Therefore, specific structural and functional details disclosed herein should not be construed as limiting, but merely as a representative basis for teaching those skilled in the art to variously utilize the present invention.

[0016] Any one or more of the controllers or devices described herein include computer executable instructions that may be compiled or interpreted from computer programs written using a variety of programming languages ​​and / or technologies. Generally, a processor (such as a microprocessor) receives instructions from, for example, a memory, a computer readable medium, etc., and executes the instructions. The processing unit includes a non-transitory computer readable storage medium capable of executing instructions of a software program. The computer readable storage medium may be, but is not limited to, an electronic storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination thereof.

[0017] FIG. 1 shows an engine order cancellation (EOC) system 100 for a vehicle 102 having a noise signal generator 108. The noise signal generator 108 may generate a reference noise signal X(n) corresponding to audible engine order noise of each engine order originating from the vehicle's engine and exhaust system 110. The EOC system 100 may be integrated with a feedforward and feedback active noise control (ANC) framework or system 104 that generates an anti-noise signal by adaptive filtering of the noise signal X(n) from the noise signal generator 108 using one or more microphones 112. The anti-noise signal Y(n) may then be played through one or more speakers 124. S(z) represents the transfer function between a single speaker 124 and a single microphone 112. It should be noted that while FIG. 1 shows a single noise signal generator 108, microphone 112, and speaker 124 for simplicity only, a typical EOC system may include multiple engine order noise signal generators 108 in addition to multiple speakers 124 (e.g., 4-8) and microphones 112 (e.g., 4-6).

[0018] 2, the noise signal generator 108 may include an RPM sensor 242 that may provide an RPM signal 244 (e.g., a square wave signal) indicative of the rotation of the engine drive shaft or other rotating shaft, which is indicative of the engine rotation speed. In some embodiments, the RPM signal 244 may be obtained from a vehicle network bus (not shown). Since the radiated engine orders are directly proportional to the drive shaft RPM, the RPM signal 244 represents the frequencies produced by the drive train, including the engine and exhaust system. Thus, the signal from the RPM sensor 242 may be used to generate reference engine order signals corresponding to each of the engine orders for the vehicle. Thus, the RPM signal 244 may be used in conjunction with a lookup table 246 of RPM versus engine order frequency.

[0019] More specifically, the lookup table 246 may be used to convert the RPM signal 244 to one or more engine order frequencies. The frequency of a given detected engine order at the detected RPM retrieved from the lookup table 246 may be provided to an oscillator or frequency generator 248, which may generate a sine wave at the given frequency. The sine wave represents a noise signal X(n) indicative of the engine order noise of the given engine order. Because there may be multiple engine orders, the EOC system 100 may include multiple noise signal generators 108 and / or frequency generators 248 to generate a noise signal X(n) for each engine order based on the RPM signal 244.

[0020] An engine rotating at a speed of 1800 RPM can be said to be running at a fundamental engine order frequency, or 30 Hz (1800 / 60=30), which corresponds to the primary engine order frequency. In a four-cylinder engine, two cylinders are fired during each crank revolution, resulting in a dominant frequency of 60 Hz (30x2=60) that defines the sound of a four-cylinder engine at 1800 RPM. It is also called the "second engine order" because in a four-cylinder engine, the frequency is twice the rotational speed of the engine. At 1800 RPM, the other dominant engine orders in a four-cylinder engine are the fourth order at 120 Hz, and the sixth order at 180 Hz. In a six-cylinder engine, the firing frequency results in a dominant third engine order, and in a V10, it is the dominant fifth engine order. As the RPM increases, the firing frequency also increases proportionately. As described above, the EOC system 100 may include multiple noise signal generators 108 and / or frequency generators 248 to generate a noise signal X(n) for each engine order based on the RPM signal 244. Additionally, the ANC framework 104 (e.g., the controllable filter 118, adaptive filter controller 120, secondary path filter 122) within the EOC system 100 may be adjusted to reduce or cancel each of these multiple engine orders. For example, an EOC system that reduces the second, fourth, and sixth engine orders would require three ANC frameworks or subsystems 104, one for each engine order. Certain system components, such as the error microphone 112 and the anti-noise speaker 124, may be common to all systems or subsystems.

[0021] Referring back to FIG. 1 , characteristic frequencies of noise and vibration originating from the engine and exhaust system 110 may be sensed by one or more of the RPM sensors 242 optionally included in the noise signal generator 108. The noise signal generator 108 may output a noise signal X(n), which is a signal representative of a particular engine order frequency. As mentioned above, the noise signals X(n) are possible at different engine orders of interest. Furthermore, these noise signals may be used separately or may be combined in various ways known to those skilled in the art. The noise signal X(n) may be filtered by the secondary path filter 122 with a modeled transfer characteristic S′(z) that estimates the secondary path (i.e., the transfer function between the anti-noise speaker 124 and the error microphone 112).

[0022] Drivetrain noise (e.g., engine, driveshaft, or exhaust noise) is mechanically and / or acoustically transmitted to the passenger compartment and received by one or more microphones 112 inside the vehicle 102. The one or more microphones 112 may be located, for example, in a headrest 114 of a seat 116, as shown in FIG. 1. Alternatively, the one or more microphones 112 may be located in a headliner of the vehicle 102, or in some other suitable location for sensing the acoustic noise field heard by an occupant inside the vehicle 102. The engine, driveshaft, and / or exhaust noise is transmitted to the microphone 112 according to a transfer characteristic P(z) that represents the primary path (i.e., the transfer function between the actual noise source and the error microphone).

[0023] The microphone 112 may output an error signal e(n) representative of the noise present in the cabin of the vehicle 102 as detected by the microphone 112. In the EOC system 100, the adaptive transfer characteristic W(z) of the controllable filter 118 may be controlled by the adaptive filter controller 120. The adaptive filter controller 120 may operate according to a known least mean square (LMS) algorithm based on the error signal e(n) and the noise signal X(n) optionally filtered with a transfer characteristic S'(z) modeled by the filter 122. The controllable filter 118 is often referred to as a W filter. The LMS adaptive filter controller 120 may provide an integrated cross spectrum configured to update the transfer characteristic W(z) filter coefficients based on the error signal e(n). The process of adapting or updating W(z) that leads to improved noise cancellation is called convergence. Convergence refers to creating a W filter that minimizes the error signal e(n) for a given input signal, which is controlled by a step size that constrains the speed of adaptation. The step size is a scaling factor that determines how quickly the algorithm converges to minimize e(n) by limiting the change in the magnitude of the W filter coefficients upon each update of the controllable W filter 118.

[0024] The anti-noise signal Y(n) may be generated by an adaptive filter formed by the controllable filter 118 and adaptive filter controller 120 based on the identified transfer characteristic W(z) and the noise signal, or a combination of the noise signal X(n). The anti-noise signal Y(n) ideally has a waveform such that when played through the speaker 124, an anti-noise is generated near the microphone 112 that is substantially opposite in phase to and identical in magnitude to the engine order noise heard by the passenger's ears and the passengers in the vehicle cabin. The anti-noise from the speaker 124 may combine with the engine order noise in the vehicle cabin near the microphone 112 to cause a reduction in the engine order noise induced sound pressure level (SPL) at this location. In certain embodiments, the EOC system 100 may receive sensor signals from an acoustic energy sensor, an acoustic intensity sensor, or other acoustic sensors in the passenger compartment, such as an acoustic particle velocity sensor or an acceleration sensor, to generate the error signal e(n).

[0025] Vehicles often have other shafts that rotate at other speeds compared to the engine RPM. For example, the drive shaft rotates at a speed associated with the engine by the current gear ratio set by the transmission. The drive shaft may have some eccentricity, so the drive shaft may not have perfect rotational balance. When rotating, the eccentricity creates a rotational imbalance that applies vibration forces to the vehicle, and these vibrations may cause audible noise in the passenger compartment. Other rotating shafts that rotate at different speeds than the engine include half shafts, or axles, that rotate at a speed set by the gear ratio in their differential. In certain embodiments, the noise signal generator 108 may have RPM sensors on different rotating shafts, such as the drive shaft or half shaft.

[0026] During operation of the vehicle 102, the processor 128 may collect and optionally process data from the RPM sensor 242 and the microphone 112 in the noise signal generator 108 to build a database or map containing data and / or parameters for use by the vehicle 102. The collected data may be stored locally in the storage 130 or in the cloud for future use by the vehicle 102. Examples of types of data related to the EOC system 100 that may be useful to store locally in the storage 130 include, but are not limited to, RPM history, microphone spectrum or time-dependent signals, microphone-based acoustic performance data, EOC tuning parameters based on driving mode, and dominant engine orders. Additionally, the processor 128 may analyze the RPM sensor and microphone data and extract key features to determine a set of parameters to be applied to the EOC system 100. The set of parameters may be selected when triggered by an event. In one or more embodiments, the processor 128 and the storage 130 may be integrated with one or more EOC system controllers, such as the adaptive filter controller 120.

[0027] The simplified EOC system schematic shown in FIG. 1 shows one secondary path between each speaker 124 and each microphone 112, denoted as S(z). As mentioned above, an EOC system typically has multiple speakers, microphones, and noise signal generators. Thus, a 6-speaker, 6-microphone EOC system has a total of 36 secondary paths (i.e., 6x6). Correspondingly, a 6-speaker, 6-microphone EOC system may similarly have 36 S'(z) filters (i.e., secondary path filters 122) that estimate transfer functions for each secondary path. As shown in FIG. 1, the EOC system also has one W(z) filter (i.e., controllable filter 118) between each noise signal X(n) from the noise signal generator 108 and each speaker 124. A 5-noise signal generator, 6-speaker EOC system may have 30 W(z) filters. Alternatively, a six frequency generator 248, six speaker EOC system may have 36 W(z) filters.

[0028] As mentioned above, the EOC system can be tuned starting with a single wide open throttle (WOT) data recording session. The dominant engine order is identified by examining the sound recorded at the crew's ear versus RPM. For each engine order, a single value for each of the key EOC algorithm parameters is typically identified. These EOC algorithm parameters typically include step size, stability SPL threshold, leakage, gain, etc. As mentioned above, step size is a scaling factor that determines how quickly the algorithm converges to minimize the error signal e(n) by limiting the change in the magnitude of the W filter coefficients based on each update of the controllable W filter. In adaptive LMS filtering, leakage refers to a step in the W filter update process. The W filter adapts by adding a term based on the error signal and step size to the previous W filter. When adding this update term, the previous W filter can also be reduced by multiplying it by a term less than one. Using leakage is the process of multiplying the magnitude of the previous W filter by a coefficient less than one during adaptation. The stability SPL threshold refers to a threshold applied to the error microphone output signal (i.e., error signal e(n)) above which the EOC system is at least temporarily deactivated. Finally, gain refers to an increase or decrease in amplitude of the output of the frequency generator 248 or any component in the noise signal generator 108 that causes an increase or decrease in the amplitude of X(n). In an alternative embodiment, the gain would refer to an increase or decrease in the amplitude of the anti-noise signal Y(n). In another alternative embodiment, the gain would refer to an increase or decrease in the amplitude of the controllable filter 118. A possible advantage of adjusting the gain in the anti-noise signal Y(n) or in the noise signal X(n) based on the driving mode is to adapt more quickly to the new driving mode. For example, when moving from a higher to a lower engine noise driving mode, decreasing the gain of the anti-noise signal Y(n) may help the W filter adapt to the new lower desired level of anti-noise more quickly than relying solely on a step-size gated W filter update process.

[0029] A single value of each of these algorithm parameters per engine order will not provide an optimal EOC experience for all vehicle driving scenarios (e.g., WOT vs. constant speed driving). Furthermore, the engine order that dominates during a WOT event is not necessarily the same as the order that dominates during idle mode and other vehicle driving modes. One or more embodiments of the present disclosure are directed to selecting an optimal set of EOC algorithm parameters based on the current vehicle operating condition or driving mode.

[0030] During a WOT event, the change in engine or other shaft RPM over time is large, so the engine order frequencies also change rapidly. In most cases, WOT situations exhibit the highest interior noise levels due to higher torque demands compared to constant speed or partial open throttle driving scenarios. A large step size is typically required for the EOC to maintain convergence (i.e., for the EOC system to continue reducing engine order noise) when engine order frequencies are changing rapidly or when engine noise levels are high. Additional leakage may also be required to maintain stability (i.e., avoid divergence) with rapidly changing frequencies using a relatively large step size.

[0031] However, when the vehicle is operated at steady state, the RPM is essentially constant and the vehicle's sound characteristics change. In this case, the step size may be reduced to improve noise cancellation since the LMS-based EOC system converges more accurately to the minimum acoustic energy with a small step size. Furthermore, a small step size may be utilized to reduce the audibility of "ANC wobble" or "ANC wander" where the LMS algorithm oscillates between several W filters (magnitude and phase values) and creates audible and undesirable fluctuations in the cancellation level. Furthermore, this small step size does not require high leakage values ​​to maintain stability. Thus, leakage can be reduced or eliminated to further improve the EOC cancellation depth and make the vehicle interior quieter. Thus, an aggressive leakage and step size may provide the best EOC during WOT. On the other hand, a less aggressive leakage and step size may provide the best EOC during steady state.

[0032] Any single set of EOC tuning parameters would of course compromise noise cancellation performance or stability under all driving conditions. Also, utilizing EOC parameters that are dependent on the driving scenario may facilitate specific EOC tuning, e.g., for known corners and divergence of the EOC algorithm after operating the vehicle for an extended period of time at highway speeds (i.e., steady state RPM). By providing a separate set of tuning parameters for this driving mode, compromises are unnecessary and divergence avoidance or stability is improved.

[0033] There are many more driving scenarios possible than just WOT and constant speed. Intermediate values ​​of tuning parameters may be possible at intermediate, or partial open throttle (POT) positions. Driving modes can be detected and labeled by monitoring the time history of RPM, speed, and torque, along with possible additional inputs from the vehicle controller area network (CAN) bus or from other systems. Non-limiting examples of various driving modes that may be detected and labeled may include WOT, towing, steady state at various speeds (e.g., 75 mph, 60 mph, and 30 mph), cylinder deactivation, coast down, partial open throttle (POT), idle, etc. FIG. 3 is a graph showing SPL in the cabin versus engine order for some of the driving modes mentioned above to demonstrate the effect of driving modes on engine order noise in the cabin.

[0034] In addition to monitoring the time history of RPM, speed, and torque, monitoring cruise control engagement or transmission gear status are other possible ways to identify vehicle operating modes. For example, a WOT (Wide Open Throttle) condition can be detected by the rate of change of RPM, sudden downshifts through multiple gears, rate of fuel flow into the engine (cylinders), rate of change of vehicle speed, pedal position, rate of change of engine torque output, vehicle acceleration values, etc. A POT (Partial Open Throttle) condition is a lower threshold for the same quantities listed above for WOT.

[0035] Towing may be detected by increased engine torque per RPM compared to "normal driving". For example, a range of engine output torque may be stored for "normal driving". If the torque exceeds this range of values ​​then a "tow" mode may be identified. Although not specifically mentioned, a "slope driving" mode (e.g., for climbing a mountain) is similar to the tow mode in both the detection method and the ideal EOC parameter selection. The two modes could be distinguished, for example, by input from an angular position sensor indicating the angle of the vehicle relative to the horizontal position.

[0036] A constant speed driving mode may be detected by a zero or negligible rate of change of RPM during a particular period of time. Cylinder deactivation may be detected by CAN messages or by acoustic detection of different engine orders. For example, when an eight cylinder engine stops operating two cylinders, it will emit the engine orders of a six cylinder engine (i.e., the third, sixth and ninth engine orders) rather than the second, fourth and sixth engine orders emitted by an eight cylinder engine. A coast down driving mode may be detected by a negative rate of change of RPM or by application of brakes within a particular force tolerance.

[0037] An idle condition can be identified by the engine running at a constant speed between cold and warm idle RPM. An alternative or secondary identification method is to simply detect that the vehicle's engine is on but the vehicle speed is substantially zero. The state of the transmission gear may also assist in identifying idle, but the gear state may be either park or drive at idle.

[0038] FIG. 4 is a schematic block diagram illustrating an EOC system 400 according to one or more embodiments of the present disclosure. The EOC system 400 may be a Filtered-X Least Mean Square (FX-LMS) EOC system, as will be appreciated by those skilled in the art. Similar to the EOC system 100, the EOC system 400 may include elements 408, 410, 412, 418, 420, 422, and 424, which are consistent with the operation of elements 108, 110, 112, 118, 120, 122, and 124, respectively, described above. FIG. 4 also illustrates the primary path P(z) and secondary path S(z) described with respect to FIG. 1. Since the engine order noise is narrowband, the error microphone signal e(n) may be filtered by a bandpass filter 450 before passing to the LMS-based adaptive filter controller 420. In one embodiment, the noise signal X(n) output by the noise signal generator 408 is bandpass filtered using the same bandpass filter parameters. Since the frequencies of the various engine orders are different, each engine order may have its own bandpass filter with different highpass and lowpass corner frequencies. The number of frequency generators and corresponding noise cancellation components will ultimately vary based on the number of engine orders for which level reduction is desired for a particular vehicle.

[0039] To detect the vehicle driving mode, the EOC system 400 may further include a driving mode detector 462. The driving mode detector 462 may include a processor and memory (not shown), such as the processor 128 and storage 130, programmed to identify and label various driving modes or driving scenarios as described above. Again, this driving mode detection may involve monitoring RPM, speed and torque time history, cruise control engagement, transmission gear status, etc. The driving mode detector 462 may be a dedicated controller for detecting the vehicle's driving mode or may be integrated with another controller or processor in the EOC system 400, such as the LMS adaptive filter controller 420. Alternatively, the driving mode detector 462 may be integrated with another controller or processor in the vehicle 102 that is separate from other components of the EOC system.

[0040] The driving mode detection scheme may result in identification of a particular driving mode after any period of analysis of the induction signal. For example, a driving mode may be identified after as little as 10 milliseconds of data analysis, with improved detection occurring after 100 milliseconds. Additionally, driving mode detection may be utilized continuously at regular time intervals and / or in response to a particular event. Such events may include, but are not limited to, receipt of a CAN message, an input identifying engagement of cruise control, an input identifying a change in transmission state from drive to park, receipt of a signal indicating the accelerator pedal is fully depressed, etc.

[0041] FIG. 5 is an exemplary flow chart illustrating a method 500 for optimizing EOC adjustment parameters based on vehicle driving mode, according to one or more embodiments of the present disclosure. Sensor data, including the types described above, may be acquired at step 510. For example, the system may monitor or receive signals indicative of vehicle driving conditions. As described above, this may involve monitoring time histories of RPM, speed, and torque, pedal position, fuel flow, as well as signals indicative of cruise control engagement, transmission gear status, etc. At step 520, the data may be analyzed and statistics may be calculated. For example, the driving mode detector 462 or another controller may calculate the rate of change of RPM, the rate of change of vehicle speed, or the rate of change of torque output of the engine. At step 530, the resulting statistics may be compared to predefined thresholds related to speed, pedal position, torque, etc. For example, a rate of change of RPM, speed, or torque between a first lower threshold and a second upper threshold may be indicative of a POT driving mode, while a rate of change above the second upper threshold may be indicative of a WOT driving mode. Additionally, the CAN message may optionally be received and compared to a list of CAN messages that identify a particular mode of operation.

[0042] Driving mode detector 462 may determine whether a change in driving mode has occurred, as shown in step 540. If the driving mode has not changed, no parameter change is necessary and new sensor data may be acquired at step 510, as shown. However, if a new driving mode is detected at step 540, driving mode detector 462 may send a signal 466 to adaptive filter controller 420 indicative of the current driving mode or driving scenario. In response to signal 466, adaptive filter controller 420 may modify one or more of the LMS algorithm parameters, as shown in step 550. For example, the step size and leakage may be adjusted to appropriate values ​​depending on the rate of change of the vehicle's current RPM.

[0043] FIG. 6 is an exemplary table 600 showing EOC adjustment parameters for each driving scenario. The four main adjustment parameters mentioned above may be intelligently adjusted based on the driving mode to maximize the EOC system performance. As shown, each adjustment parameter may be assigned a separate state (e.g., high / low, high / medium / low) based on the driving mode detected. For each adjustment parameter, a corresponding value associated with each state may be applied in the EOC algorithm by the adaptive filter controller 420. Alternatively, the table 600 may include specific numerical values ​​for each adjustment parameter to further optimize the EOC based on the various driving modes. These specific numerical values ​​may be predetermined and stored in the memory 130. For example, when moving from a low step size driving mode to a medium step size driving mode, the step size may be increased by a predetermined amount, such as 10 dB or 20 dB. When moving back from a medium step size driving mode to a low step size driving mode, the step size may be decreased by a predetermined amount, such as 10 or 20 dB. In one embodiment, when moving from a high leak to a low leak mode of operation, the leak value may be decreased a predetermined amount, such as 50% or 73%, In another embodiment, when moving from a high stability SPL threshold to a low stability SPL threshold, the SPL threshold may be reduced a predetermined amount, such as 10 dB.

[0044] In one or more embodiments, when a new driving mode (i.e., a gear shift) is identified (i.e., a change in driving mode is detected), the step size may be initially increased for a short period of time to reduce the adaptation time to this new driving mode. Following this short duration, the primary tuning parameters (including the step size) may be adjusted according to table 600 of FIG. 6 based on the particular driving mode detected.

[0045] In addition to modifying the EOC tuning parameters, engine order noise from dominant engine orders may be reduced based on the driving mode and / or transmission mode. Due to processing power and other EOC system limitations, the EOC system 400 and its corresponding algorithms may be limited in the number of engine order noise amplitudes that it can reduce. The number of machine code instructions that a computer can process while running a "standard" program is measured in MIPS (million instructions per second). Thus, for example, for a given MIPS and memory limitations, the EOC algorithm may only be able to reduce the amplitudes of five engine orders. Canceling more engine orders would require additional digital signal processing (DSP) resources that may not be available or desirable. However, the five dominant engine orders may be different for various driving or transmission modes.

[0046] The transmission modes may include, but are not limited to, Sport, Economy (ECO), Snow, Tow, Baja, Lock, and Truck. The transmission modes change the torque demand and the gear shift points on the engine, thereby changing the engine order levels. FIG. 7 is an exemplary plot showing relative SPL versus engine order measured on one vehicle in two different driving modes. The measurements in the first driving mode were taken while the vehicle was stationary and the engine was at warm idle speed. The measurements in the second driving mode were taken during WOT. As shown in FIG. 7, the five dominant engine orders are different in these two vehicle driving modes. Additionally, the single most dominant engine order also differs between these two driving modes. Two of the five most dominant engine orders differ by more than 15 dB between these two driving modes.

[0047] Therefore, to optimize EOC without dedicating DSP resources to cancel all engine orders, the EOC system 400 and corresponding algorithms may target the dominant engine orders at each driving mode, rather than just the dominant engine orders at WOT. If the EOC system can target five engine orders for noise cancellation, then the algorithm may select the five most dominant engine orders to target based on the driving mode or transmission mode. An additional benefit of using the gear or transmission state to identify the vehicle driving mode relates to driveline cancellation. As is commonly understood, certain acoustic sounds in the passenger compartment originate from vibrations induced by rotational imbalance of the driveshaft. For each transmission gear, the driveshaft RPM is related to the engine RPM by a different coefficient (due to different gear ratios). Thus, for each gear, a different set of RPM vs. frequency lookup tables is required for the EOC algorithm to cancel driveline induced noise in the vehicle. Similarly, for each operating condition, a different set of RPM vs. frequency look-up tables may be utilized such that the EOC algorithm targets the engine orders that dominate in each operating mode.

[0048] In view of the above, once a driving mode is identified, not only can the ideal adaptation parameters that result in optimal noise cancellation of a particular engine order be loaded, but also a list of dominant engine orders for that particular new driving mode. Similar to FIG. 6, FIG. 8 is an exemplary table 800 showing dominant engine orders for a particular engine for each driving scenario. This results in an overall lower overall noise floor for the vehicle, thereby further optimizing the noise cancellation performance experienced by the vehicle occupants.

[0049] Although exemplary embodiments have been described above, it is not intended that these embodiments describe all possible forms of the present invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the present invention. Moreover, features of various implementation embodiments may be combined to form further embodiments of the present invention.

[0050] 1 and 4 show LMS-based adaptive filter controllers 120 and 420, respectively, other methods and devices for adapting or creating the optimal controllable W filters 118 and 418 are possible. For example, in one or more embodiments, a neural network may be utilized to create and optimize the W filter instead of an LMS adaptive filter controller. In other embodiments, machine learning or artificial intelligence may be used to create the optimal W filter instead of an LMS adaptive filter controller.

[0051] Those skilled in the art will appreciate that functionally equivalent processing steps can occur in either the time domain or the frequency domain. Thus, although not explicitly stated for each signal processing block in the figures, signal processing may occur in either the time domain, the frequency domain, or a combination thereof. Furthermore, although various processing steps are described in terms typical of digital signal processing, equivalent steps may be performed using analog signal processing without departing from the scope of the present disclosure.

[0052] The terms "comprise," "comprises," "comprising," "having," "including," "includes," or any variation thereof, are intended to refer to a non-exclusive inclusion, whereby a process, method, article, composition, or apparatus that includes a list of elements includes not only those elements that are listed, but may include other elements not expressly shown or inherent to such process, method, article, composition, or apparatus. Other combinations and / or modifications of the above-described structure, arrangement, application, proportions, elements, materials, or components used in the practice of the inventive subject matter, in addition to those not specifically listed, may be changed or otherwise specifically adapted to particular environments, manufacturing specifications, design parameters, or other operating requirements without departing from the same general principles.

Claims

1. 1. A method for dynamically adjusting an engine noise cancellation system based on a vehicle operating mode, the method comprising: storing in a memory a set of engine noise cancellation adjustment parameters for each of a plurality of vehicle operating modes, each set of engine noise cancellation adjustment parameters differing between the vehicle operating modes; applying a first set of engine noise cancellation tuning parameters corresponding to a current vehicle operating mode; receiving at least one signal indicative of a vehicle operating condition; detecting a change in the current vehicle operating mode based on the at least one signal; applying a second set of engine noise cancellation tuning parameters in response to a change in the current vehicle operating mode; and Including, The method, wherein the set of engine noise cancellation tuning parameters for each of the plurality of vehicle operating modes includes at least a sound pressure level threshold applied to an error signal.

2. applying the first set of engine noise cancellation tuning parameters corresponding to the current vehicle operating mode; selecting, when a first vehicle operating mode is the current vehicle operating mode, the first set of engine noise cancellation tuning parameters from a memory corresponding to the first vehicle operating mode; utilizing the first set of engine noise cancellation adjustment parameters during engine noise cancellation; Including, applying the second set of engine noise cancellation tuning parameters in response to the change in a current vehicle operating mode; in response to the change in current vehicle operating mode from the first vehicle operating mode to a second vehicle operating mode, selecting from memory the second set of engine noise cancellation tuning parameters corresponding to the second vehicle operating mode; utilizing the second set of engine noise cancellation adjustment parameters during engine noise cancellation when the current vehicle operating mode is a second vehicle operating mode. The method of claim 1 , comprising:

3. The method of claim 1 , wherein the set of engine noise cancellation tuning parameters for each of the plurality of vehicle operating modes includes at least a step size.

4. The method of claim 1 , wherein the set of engine noise cancellation tuning parameters for each of the plurality of vehicle operating modes includes at least a gain applied to one of an anti-noise signal and a noise signal.

5. The method of claim 1 , wherein the at least one signal is indicative of cruise control engagement.

6. The method of claim 1 , wherein the at least one signal is indicative of at least one of revolutions per minute (RPM), speed, and torque.

7. detecting the change in the current vehicle operating mode based on the at least one signal; Determining a rate of change of at least one of RPM, speed, and torque; comparing said rate of change to one or more predetermined thresholds; The method of claim 6, comprising:

8. The method of claim 1 , wherein the plurality of vehicle operating modes includes at least a partial open throttle operating mode and a constant speed operating mode.

9. The method of claim 8 , wherein the plurality of vehicle operating modes further comprises a wide open throttle operating mode.

10. 1. An engine noise cancellation system, comprising: at least one controllable filter configured to generate an anti-noise signal based on an adaptive transfer characteristic and a noise signal received from a noise signal generator, the adaptive transfer characteristic of the at least one controllable filter being characterized by a set of filter coefficients; An adaptive filter controller, comprising: storing a set of engine noise cancellation adjustment parameters for each of a plurality of vehicle operating modes, each set of engine noise cancellation adjustment parameters differing between the vehicle operating modes; applying the set of engine noise cancellation tuning parameters corresponding to a current vehicle operating mode; and adapting the set of filter coefficients based on the noise signal and an error signal received from a microphone located in a passenger compartment of the vehicle; an adaptive filter controller including a processor and memory programmed to execute an operating mode detector in communication with at least the adaptive filter controller, the operating mode detector comprising: receiving at least one signal indicative of a vehicle operating condition; analyzing the at least one signal to determine the current vehicle operating mode; sending a driving mode signal to the adaptive filter controller indicative of the current vehicle driving mode; an operation mode detector including a processor and memory programmed to execute the steps of: Equipped with 11. An engine noise cancellation system, wherein the set of engine noise cancellation adjustment parameters for each of the plurality of vehicle operating modes includes at least a sound pressure level threshold applied to an error signal.

11. The system of claim 10 , wherein the driving mode detector transmits the driving mode signal in response to detecting a change in the current vehicle driving mode.

12. The system of claim 10 , wherein the set of engine noise cancellation tuning parameters for each of the plurality of vehicle operating modes includes at least a step size.

13. The system of claim 10 , wherein the plurality of vehicle operating modes includes at least a partial open throttle operating mode and a constant speed operating mode.

14. The system of claim 10 , wherein the at least one signal indicative of a vehicle operating condition is indicative of at least one of revolutions per minute (RPM), speed, and torque.

15. The system of claim 10 , wherein the at least one signal indicative of a vehicle operating condition is indicative of a transmission gear condition.

16. 1. A method for dynamically adjusting an engine noise cancellation system based on a vehicle operating mode, the method comprising: storing a set of engine noise cancellation adjustment parameters for each of a plurality of vehicle operating modes, each set of engine noise cancellation adjustment parameters varying between vehicle operating modes, the set of engine noise cancellation adjustment parameters for each of the plurality of vehicle operating modes including at least a sound pressure level threshold applied to an error signal; receiving at least one signal indicative of a vehicle operating condition; detecting a current vehicle operating mode based on the at least one signal; selecting the set of engine noise cancellation tuning parameters corresponding to the current vehicle operating mode; selecting a different set of engine noise cancellation tuning parameters in response to changes in the current vehicle operating mode; A method comprising:

17. The method of claim 16 , wherein each of the plurality of vehicle operating modes corresponds to a different condition of a vehicle transmission.

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