Knock Determination Device Using Waveform Model Comparison
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Solution Overview
Problem
Existing knock determination devices for internal combustion engines often incorrectly determine whether an engine is knocking, as vibrations attributed to faults or the engine itself can be misinterpreted, leading to inaccurate assessments.
Innovation Solution
A knocking determination device that detects crank angles and vibration waveforms between predetermined angles, using a storage unit to compare detected waveforms with pre-stored knock waveforms specific to engine states or operations, allowing for accurate identification of knocking occurrences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a single knock waveform model is used for all engine types and states, then data storage requirements are reduced and setup is simplified, but the ability to accurately distinguish knocking from other vibrations may be compromised
Solution Approach 1:
The patent extracts only the essential characteristic features of knock waveforms (such as specific frequency ranges, amplitude patterns, and temporal characteristics) rather than storing complete waveform data. This extraction approach maintains detection accuracy while significantly reducing data storage requirements.
Solution Approach 2:
The patent transforms the knock detection approach by changing parameters from storing complete waveforms to storing simplified waveform characteristics and using adaptive thresholding. This parameter transformation enables a single model to effectively handle different engine types and operating states without requiring extensive data storage for each specific condition.
2Device complexity
If vibration magnitude threshold is used to determine knocking, then simple detection is achieved, but vibrations from engine faults or normal operation may be misidentified as knocking
Solution Approach 1:
The patent performs preliminary analysis of vibration waveforms by comparing them against stored knock waveform characteristics before making a knocking determination. This preliminary comparison action filters out false positives from engine faults or normal operation vibrations, improving identification accuracy while maintaining relatively simple detection methodology.
Solution Approach 2:
The system incorporates feedback mechanisms where detection results are continuously refined by comparing against established knock waveform patterns. This feedback loop enables the system to distinguish true knocking events from other vibrations by evaluating multiple waveform characteristics rather than relying on simple magnitude thresholds alone.
Data Source
AI summary
An engine ECU executes a program including the steps of: setting a knock waveform model corresponding to engine speed sensed by a crank position sensor; calculating knock intensity N based on the result of comparison between a detected waveform and the set knock waveform model; when the knock intensity N is larger than a predetermined reference value, determining that knocking has occurred; and when the knock intensity N is not larger than the predetermined reference value, determining that knocking has not occurred.