Engine Control Unit Disturbance Detection via Frequency Component Analysis
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Solution Overview
Problem
Existing control systems for internal combustion engines face accuracy issues in determining disturbances, as fluctuation rates of rotational speed can be misinterpreted due to unstable combustion or lack thereof, leading to incorrect determination of disturbance occurrence.
Innovation Solution
A control apparatus equipped with an electronic control unit that analyzes rotational speed signals by extracting first-order and n-th-order components, using thresholds to differentiate between disturbances and unstable combustion, thereby improving the accuracy of disturbance detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the fluctuation rate of rotational speed is used to determine disturbance occurrence, then the determination process is simple, but the accuracy deteriorates due to periodic fluctuations and unstable combustion
Solution Approach 1:
The rotational speed signal is segmented into multiple frequency components (first-order, second-order, and higher-order components) corresponding to different combustion cycles. By analyzing each component separately, the system can distinguish between periodic fluctuations (affecting all components uniformly) and actual disturbances (affecting specific components), thereby improving determination accuracy without significantly complicating the overall process.
Solution Approach 2:
Instead of analyzing the entire rotational speed signal or using only the first-order component, the invention selectively analyzes specific higher-order components (n-th order where n≥2) in addition to the first-order component. This partial analysis of excessive components allows the system to capture disturbance characteristics that would be missed by simple first-order analysis, improving accuracy while maintaining reasonable computational complexity.
2Ease of manufacture
If the fluctuation rate is calculated using consecutive rotational speed detections, then the calculation is straightforward, but false negatives occur when the detection period coincides with fluctuation cycles
Solution Approach 1:
The invention transitions from time-domain analysis (comparing consecutive rotational speed values) to frequency-domain analysis by extracting components at different combustion cycle orders. This dimensional change allows the system to detect disturbances regardless of the detection timing relative to fluctuation cycles, as frequency components reveal periodic patterns that time-domain comparisons may miss.
Solution Approach 2:
The invention introduces frequency component extraction as an intermediary step between raw rotational speed detection and disturbance determination. By using Fourier analysis or similar techniques to extract first-order, second-order, and higher-order components, the system creates an intermediate representation that reveals the true nature of rotational speed variations, enabling more reliable disturbance detection.
3Device complexity
If only the first-order component is analyzed for disturbance detection, then the detection method is simple, but false positives occur due to unstable combustion states
Solution Approach 1:
The invention extracts and separately analyzes higher-order components (n-th order where n≥2) in addition to the first-order component. By taking out these additional frequency components for analysis, the system can distinguish between unstable combustion (which primarily affects the first-order component) and actual disturbances (which affect multiple components including higher-order ones), thereby reducing false positives while maintaining manageable complexity.
Data Source
AI summary
A control apparatus for an internal combustion engine (i) acquires a rotational speed signal correlated with a rotational speed of the internal combustion engine, (ii) extracts, from the acquired rotational speed signal, at least first-order and lower-order than the first-order components of the rotational speed signal, (iii) extracts, from the acquired rotational speed signal, at least an n-th-order component of the rotational speed signal, (iv) determines that no disturbance has occurred when a first-order parameter regarding a magnitude of an amplitude of the extracted first-order and lower-order than the first-order components is smaller than a first threshold, and (v) determines that a disturbance has occurred when the first-order parameter is equal to or larger than the first threshold and an n-th-order parameter regarding an amplitude of the extracted n-th-order component is equal to or larger than a second threshold.