Engine Speed Extrapolation for Active Vehicle Noise Control
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Solution Overview
Problem
Active noise reduction systems in motor vehicles face challenges due to the limited availability of continuous engine speed reference signals, which are necessary for effective noise compensation, especially when the engine speed changes rapidly during acceleration and braking, leading to suboptimal noise reduction performance.
Innovation Solution
A method that extrapolates the engine speed reference variable using a time-discrete extrapolation model, allowing for the generation of a practically continuous reference signal, which is then used to control the compensation noise introduction with high amplitude and phase precision, eliminating the need for additional measurement sensors and cabling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a digital bus system with low sampling rate (e.g., CAN bus) is used to transmit engine speed data, then device complexity is reduced and integration with existing systems is improved, but the reference variable is only available at discrete time intervals (e.g., every 100 milliseconds), which reduces the responsiveness and effectiveness of active noise reduction during dynamic engine operation
Solution Approach 1:
The patent applies preliminary action by using an extrapolation model to predict future engine speed values based on historical data from the digital bus. This allows the noise reduction system to have reference signals available before they are actually transmitted over the low-speed bus, effectively preparing the system in advance for upcoming noise conditions and eliminating the time delay caused by discrete sampling.
Solution Approach 2:
The patent creates a copied and enhanced version of the discrete reference signal by generating a continuous reference signal through extrapolation. Instead of directly using the sampled engine speed data from the CAN bus, the system creates a continuous time-series copy that fills in the gaps between samples, maintaining the benefits of digital bus integration while restoring temporal continuity for effective noise control.
2Measurement precision
If additional measurement sensors and cabling are installed to provide continuous reference signals, then measurement precision and real-time control capability are improved, but device complexity and installation cost increase
Solution Approach 1:
The patent introduces an intermediary - the extrapolation model - that mediates between the discrete digital bus data and the continuous noise reduction control requirements. This mathematical intermediary processes the existing digital bus signals to generate continuous reference signals, eliminating the need for additional physical sensors and cabling while achieving the desired measurement precision and temporal continuity.
Solution Approach 2:
The patent replaces the mechanical approach of adding physical sensors and wiring with a computational approach using signal extrapolation. Instead of mechanically extending the sensing infrastructure, the system uses algorithms to generate continuous reference signals from discrete digital bus data, substituting mechanical complexity with computational processing.
3Use of energy by moving object
If the reference signal is updated at a low rate (e.g., 10 times per second), then energy consumption is reduced and communication load on the digital bus is minimized, but the noise reduction system cannot adapt quickly enough to rapid changes in engine speed during acceleration and braking
Solution Approach 1:
By using extrapolation to predict future engine speed values, the system performs preliminary action to prepare reference signals for upcoming noise conditions. This allows the noise reduction actuators to respond proactively to anticipated changes rather than reactively to past changes, significantly improving adaptability during rapid engine transients while keeping the actual data communication rate low.
Solution Approach 2:
The patent applies dynamics by making the reference signal generation adaptive and time-varying through the extrapolation model. The system dynamically adjusts the reference signal based on the current operating state and historical trends, enabling rapid adaptation to changing engine conditions without requiring a high fixed sampling rate, thus maintaining energy efficiency while improving responsiveness.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables reliable and efficient active noise reduction across varying engine speeds by providing real-time adaptation of compensation noise, improving noise reduction performance and eliminating the need for additional measurement sensors and cabling.
Implementation Method 1
the characteristic reference variable which is present in a time-discrete manner is extrapolated proceeding from the respective readout instants, at least two values of the reference variable which have been read out beforehand with respect to time being used in an extrapolation model
Implementation Method 2
the noise is reduced by superimposition of additional vibrations, so-called anti-noise
Implementation Method 3
Systems for actively influencing noise, which are also called ANC systems (active noise control), are used, for example, in a passenger compartment of a motor vehicle to reduce the noise level of a source of disturbance
Data Source
AI summary
Method for influencing noise, wherein a noise source (16), in particular an engine in a motor vehicle, generates the noise with a substantially periodically variable excitation, and wherein a reference variable which is characteristic of the noise source, in particular an engine speed, is present at predetermined successive supply instants (ti), comprising the method steps; reading out at least a first value (Ni−1) of the reference variable at a first supply instant (ti−1) and a second predetermined value at a second supply instant (ti); generating the reference signal (12) at at least one instant (t) between the second supply instant (ti) and a third supply instant (ti+1) as a function of the first and second values that were read out; and sending the reference signal (12) to a device for actively influencing noise (11), which generates activation signals (13) for at least one actuator (14) as a function of the reference signal (12), wherein the at least one actuator (14) emits compensation sound, which interferes with the noise.