Knock Determination Value Correction with Bounded Limits
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Solution Overview
Problem
Existing methods for determining knocking in internal combustion engines often lead to inaccurate results due to variations in vibration magnitude, which can result in incorrect determination of knocking occurrence, affecting precision.
Innovation Solution
A device with a knock sensor and an operation unit that calculates a first value based on vibration magnitude, corrects a second value using magnitudes from multiple ignition cycles, and sets upper and lower limits for the second value to ensure it remains within appropriate ranges, preventing extreme corrections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the knock determination value is corrected without limitation based on the frequency of occurrence of knocking, then the determination value adapts to different engine conditions, but the precision of knocking determination deteriorates due to extreme corrections making the value too large or too small
Solution Approach 1:
The knock determination value is dynamically corrected based on the frequency of knocking occurrence, allowing the system to adapt to different engine conditions. The correction amount varies according to how frequently knocking is detected, making the determination value flexible and condition-dependent rather than fixed.
Solution Approach 2:
The knock determination value is adjusted by changing its parameter (magnitude) based on the frequency of knocking occurrence. When knocking occurs frequently, the determination value is increased; when knocking occurs rarely, the determination value is decreased. This parameter change enables the system to adapt to different operational conditions while maintaining determination accuracy through bounded correction.
2Productivity
If the knock determination value is corrected to a very large or very small value, then the correction strongly responds to knocking frequency, but false determination occurs because the value becomes too large or too small relative to actual vibration magnitude
Solution Approach 1:
Upper and lower limit values are predetermined and stored in advance to cushion against extreme corrections. Before applying correction to the knock determination value, the system checks whether the corrected value would exceed these pre-established limits, preventing the value from becoming too large or too small and thus avoiding false determinations.
Solution Approach 2:
The system continuously monitors the frequency of knocking occurrence and uses this feedback to adjust the knock determination value. The correction process incorporates feedback loops where the determined knocking frequency directly influences the adjustment of the determination value, creating a self-regulating mechanism that responds to actual engine conditions while maintaining reliability through bounded adjustments.
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
This approach enhances the precision of knocking determination by ensuring the reference value for knocking detection is within the actual range of engine vibration, reducing false positives and negatives.
Implementation Method 1
a knock sensor detecting a magnitude of vibration of the internal combustion engine
Data Source
AI summary
An engine ECU executes a program including the steps of: calculating a magnitude value LOG(V) by logarithmically converting a magnitude V of vibration occurring in an engine, calculating a median V(50) and a standard deviation σ of magnitude values LOG(V); and setting, to the product of the standard deviation σ and a factor A, a first upper limit of a determination value V(KX) that is to be compared with a knock magnitude N for determining whether or not knocking has occurred, and setting a first lower limit of the determination value V(KX) to the product of the standard deviation σ and a factor B.