Frequency Spectrum Analysis for Engine Knocking Detection
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Solution Overview
Problem
Existing frequency spectrum analysis apparatuses for internal combustion engines fail to accurately determine knocking occurrences at high engine rotational speeds due to insufficient calculation time, leading to inaccurate results.
Innovation Solution
A frequency spectrum analyzing apparatus that samples operating parameters at predetermined intervals, calculates intensities of sine and cosine components, and uses preceding calculated values to improve calculation speed by replacing part of the integrated values when engine rotational speed exceeds a threshold, ensuring sufficient time for post-processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the frequency spectrum analysis is performed using conventional integration calculation methods, then the calculation accuracy is maintained, but the calculation time becomes excessively long at high engine rotational speeds
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing integration results in memory before they are needed. The integration calculation unit performs integration calculations in advance and stores the results, so that when frequency component intensity calculation is needed at high engine speeds, the pre-computed values can be retrieved immediately without performing the full integration calculation again, thus reducing calculation time while maintaining accuracy
Solution Approach 2:
The patent uses copying by creating and storing copies of integration results in memory. Instead of recalculating integration values during frequency spectrum analysis, the system creates copies of previously computed integration results and reuses them, significantly reducing the computational burden at high engine rotational speeds while preserving the accuracy of frequency component intensity calculations
2Productivity
If the calculation time period is shortened to meet high engine rotational speed requirements, then the productivity is improved, but the determination accuracy of knocking occurrence deteriorates
Solution Approach 1:
By performing integration calculations in advance and storing results in memory, the system prepares computation results before they are needed for knocking determination. This preliminary action ensures that when high engine speeds require rapid analysis, the necessary computational data is already available, maintaining both speed and accuracy in knocking detection
Solution Approach 2:
The system creates and stores copies of integration results that can be rapidly retrieved during knocking determination. These pre-copied values enable fast frequency spectrum analysis at high engine speeds without compromising the accuracy needed for reliable knocking occurrence detection
3Measurement precision
If the conventional frequency spectrum analysis method is used without optimization, then the measurement precision is maintained, but the device complexity increases due to insufficient time for post-processing
Solution Approach 1:
The patent segments the frequency spectrum analysis process into distinct functional units: integration calculation unit, frequency spectrum analysis unit, and post-processing unit. By dividing the system into specialized modules with dedicated functions, the complexity is distributed and managed more efficiently, allowing each unit to operate independently and optimally without requiring excessive overall system complexity
Solution Approach 2:
By storing copies of integration results in memory, the system eliminates the need for complex real-time computation during post-processing. The pre-copied data simplifies the post-processing unit's requirements, reducing overall system complexity while maintaining measurement precision through accurate frequency component intensity calculations
Data Source
AI summary
A frequency spectrum analyzing apparatus for performing a frequency spectrum analysis with respect to a detected value of an operating parameter of an internal combustion engine in synchronism with rotation of the engine, is provided. The operating parameter is sampled at predetermined time intervals, and a sampled value is converted to a digital value. Intensities of first and second elements are calculated with respect to a predetermined number of the sampled values. The first elements and second elements respectively correspond to a plurality of frequency components contained in the detected value, and a phase of the second element differs from a phase of the first element by 90 degrees. Frequency component intensities corresponding to the plurality of frequency components are calculated in synchronism with rotation of the engine, using the first element intensities and the second element intensities. The frequency component intensities are calculated by replacing a part of an integrated value of the first element intensities, and a part of an integrated value of the second element intensities respectively with corresponding preceding calculated values, when an rotational speed of the engine is higher than or equal to a set threshold value.