Knocking Determination Device Frequency Band Segmentation
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Solution Overview
Problem
Existing knocking determination devices for internal combustion engines face challenges in accurately distinguishing between vibrations caused by knocking and noise, leading to reduced accuracy in knocking detection due to varying frequency components and noise interference.
Innovation Solution
A knocking determination device that extracts vibrations at both a predetermined frequency band and a broader frequency band, allowing for comparison with stored waveforms to differentiate between knocking and noise components, thereby enhancing the accuracy of knocking detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a predetermined frequency band is used to extract knocking vibrations, then the magnitude of knocking vibrations can be detected, but noise components in broader frequency bands cannot be removed
Solution Approach 1:
The patent divides the frequency spectrum into multiple bands: a predetermined frequency band for extracting knocking vibration magnitudes, and a broader frequency band for extracting waveform characteristics. This segmentation allows independent processing of magnitude and waveform data to distinguish knocking from noise
Solution Approach 2:
Different frequency bands are assigned different functions: the predetermined frequency band focuses on magnitude detection while the broader band captures waveform shape. This local specialization of frequency bands enables the system to simultaneously detect magnitude and waveform characteristics without mutual interference
2Measurement precision
If a broader frequency band is used to extract vibrations, then waveform detection can be performed, but noise components cannot be removed
Solution Approach 1:
The patent separates waveform extraction from magnitude detection by using different frequency bands. The broader frequency band is dedicated to waveform extraction while the predetermined band handles magnitude, allowing noise removal through comparative analysis
Solution Approach 2:
The patent introduces a control unit as an intermediary that compares waveform data from the broader frequency band with magnitude data from the predetermined frequency band. This intermediary processing enables distinction between actual knocking and noise components
3Productivity
If frequency components in predetermined frequency bands are detected, then knocking detection can be performed, but accuracy deteriorates due to varying frequency components and noise
Solution Approach 1:
The patent dynamically adjusts the analysis by comparing both magnitude and waveform characteristics. Instead of relying on a fixed frequency threshold, the system adapts its determination criteria based on the relationship between magnitude data and waveform shape, improving accuracy under varying operating conditions
Solution Approach 2:
The control unit uses feedback from both the magnitude detector and waveform extractor to make knocking determinations. The system continuously compares the relationship between magnitude and waveform characteristics against predetermined thresholds, adjusting its determination based on this feedback loop
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
The device achieves high accuracy in determining whether knocking occurred by isolating vibrations specific to knocking and removing noise components, ensuring precise waveform detection and operation state control of the engine.
Implementation Method 1
a vibration detecting unit detecting vibrations of an internal combustion engine
Data Source
AI summary
An engine ECU includes a bandpass filter (1) extracting only vibrations at a first frequency band A, a bandpass filter (2) extracting only vibrations at a second frequency band B, a bandpass filter (3) extracting only vibrations at a third frequency band C, and a bandpass filter (4) extracting only vibrations at a fourth frequency band D including the first to third frequency bands A-C. The engine ECU determines whether knocking occurred or not based on a vibration waveform of the fourth frequency band D and a peak value in magnitude of vibrations in a synthesized waveform of the first to third frequency bands.