Knock Sensor Signal Decomposition for Internal Combustion Engine Control
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Solution Overview
Problem
Existing internal combustion engine knock control systems fail to accurately detect knocking when the opening/closing timing of intake and exhaust valves overlaps with knocking occurrences.
Innovation Solution
An internal combustion engine control apparatus that uses a knock sensor signal input to an electronic control device, applying short-time Fourier transform and semi-supervised non-negative matrix factorization to decompose vibration data into knocking and mechanical vibration components, enabling precise knocking detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If frequency analysis is performed using a fixed knock analysis section, then the system structure is simple, but knocking cannot be detected when valve timing overlaps with knocking occurrence
Solution Approach 1:
The knock analysis section is made dynamic by adjusting its timing based on the opening/closing timing of intake and exhaust valves. The control device determines a corrected knock analysis section that avoids overlapping with valve timing, allowing accurate knocking detection without fixed rigid boundaries. This dynamic adjustment resolves the contradiction by adapting the analysis window to operating conditions.
Solution Approach 2:
The timing parameters of the knock analysis section are changed based on valve timing information. By modifying the start and end points of the knock analysis section according to intake/exhaust valve opening and closing timings, the system achieves accurate knocking detection under varying operating conditions while maintaining a relatively simple overall system structure.
2Measurement precision
If the knock analysis section is adjusted based on valve timing, then knocking detection accuracy improves, but the control processing becomes more complex
Solution Approach 1:
The control device preliminarily determines the corrected knock analysis section by acquiring intake/exhaust valve opening and closing timings before performing frequency analysis. This preliminary timing adjustment ensures that the knock analysis section does not overlap with valve timing, improving detection accuracy while organizing the control flow in a systematic manner that manages complexity.
Solution Approach 2:
The system uses feedback from valve timing information to continuously adjust the knock analysis section. By incorporating valve timing data into the determination of the knock analysis section, the system maintains accurate knocking detection across different operating conditions, with the feedback mechanism managing the complexity through structured information flow.
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
Accurately detects knocking by removing mechanical noise, preventing erroneous determinations and ensuring effective control without complicating the system, thus maintaining the ability to detect abnormal combustion.
Implementation Method 1
a signal from a knock sensor configured to detect vibration of an internal combustion engine is to be input
Implementation Method 2
subject the signal from the knock sensor to short-time Fourier transform, to thereby generate an observation matrix
Implementation Method 3
subject a noise basis matrix obtained by subjecting a signal from the knock sensor in a state in which mechanical vibration other than knocking occurs to non-negative matrix factorization and the observation matrix to semi-supervised non-negative matrix factorization, to thereby decompose the observation matrix into knocking vibration data being data on vibration caused by knocking and mechanical vibration data being data on vibration other than the knocking
Data Source
AI summary
In an internal combustion engine control apparatus, an electronic control device is configured to subject a signal from a knock sensor to short-time Fourier transform, to thereby generate an observation matrix. Further, the electronic control device is configured to decompose the observation matrix into knocking vibration data being data on vibration caused by knocking and mechanical vibration data being data on vibration other than the knocking.