Engine Knock Controller Using Minimum Value Background Level
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Solution Overview
Problem
Existing knock control systems for internal combustion engines face challenges in accurately detecting knocking occurrences due to distortion in the frequency distribution of knock signals, leading to inappropriate ignition timing adjustments and increased computational load.
Innovation Solution
A controller system that calculates a background level using a low pass filter with adjustable cutoff frequencies and performs minimum value detection processing to maintain accurate knock decision thresholds, regardless of frequency distribution distortions, thereby enhancing knock detection and suppression capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the average value of knock signal is calculated using low pass filter to determine background level, then knock detection is performed, but frequency distribution distortion causes background level to shift above expected value leading to inappropriate knock detection
Solution Approach 1:
The patent changes the parameter used for background level calculation from average value to minimum value. By using minimum value detection, the system identifies the lowest point in the knock signal frequency distribution, which remains stable even when the distribution is distorted by knocking occurrences. This parameter change resolves the contradiction by preventing the background level from shifting above the expected value while maintaining reliable knock detection.
2Measurement precision
If median and standard deviation are calculated to determine background level, then knock detection is performed, but square calculation and square root calculation increase processing load
Solution Approach 1:
The patent extracts only the minimum value from the knock signal frequency distribution to determine the background level, rather than calculating the entire distribution characteristics including median and standard deviation. This extraction approach eliminates the need for complex square calculations and square root calculations while maintaining sufficient accuracy for knock detection, thereby reducing computational load.
3Measurement precision
If background level is calculated by subtracting constant times standard deviation from median, then background level is determined, but frequency distribution distortion causes background level to deviate below distribution range or approach median
Solution Approach 1:
The patent changes the background level determination method from using median and standard deviation to using minimum value detection. The minimum value in the frequency distribution represents the lowest point that remains stable even when the distribution shape changes due to knocking. This parameter change ensures that the background level is determined consistently below the main distribution range, maintaining stability regardless of frequency distribution distortion.
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 system effectively detects knocking occurrences and suppresses them by maintaining stable background levels, even with distorted frequency distributions, ensuring appropriate ignition timing adjustments and reducing computational load.
Implementation Method 1
calculates a background level by processing a low pass filter to the knock signal
Data Source
AI summary
To provide a controller and a control method, for an internal combustion engine, that can detect occurrence of knocking appropriately, even though the frequency distribution of the knock signal is distorted according to the occurrence state of knocking. The controller for the internal combustion engine calculates the background level by processing a low pass filter to the knock signal; and performs a low side frequency increase which makes a low side frequency, which is a cutoff frequency of the low pass filter in the case where the knock signal is smaller than an output value of the low pass filter, higher than a high side frequency, which is a cutoff frequency of the low pass filter in the case where the knock signal is larger than the output value of the low pass filter.