Engine Knock Detection Using Vibration Intensity Segmentation
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Solution Overview
Problem
Conventional knock determination apparatuses in internal combustion engines fail to accurately detect knocking due to variations in components and divergence of vibration intensity distributions, leading to false negatives during frequent knocking conditions.
Innovation Solution
A knock determination apparatus that sets a vibration intensity reference value in a region where the vibration intensity is smaller, using a mathematical expression to calculate a knock reference value with reduced influence from divergence, allowing for accurate detection of knocking while minimizing the impact of component variations and maintaining the shape of the vibration intensity distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the knock reference value is calculated using the central value of the vibration intensity distribution, then the influence of component variations is eliminated, but the knock reference value becomes very large when knocking frequently occurs, leading to failure to detect knocking
Solution Approach 1:
The patent segments the vibration intensity distribution into two regions: a first region with smaller vibration intensity values and a second region with larger vibration intensity values. The knock reference value is calculated using only data from the first region, excluding the influence of the second region where knocking data resides. This segmentation allows the system to maintain an accurate knock reference value even when knocking occurs frequently, resolving the contradiction between reliability and measurement precision.
Solution Approach 2:
The patent extracts and excludes the second region (larger vibration intensity values) from the calculation of the knock reference value. By taking out the portion of the distribution that contains knocking data, the system prevents knocking occurrences from inflating the knock reference value, thereby maintaining measurement precision while still achieving reliable knock detection through comparison of current vibration intensity against this stable reference.
2Stability of the object's composition
If the vibration intensity distribution diverges due to frequent knocking, then the knock reference value becomes very large, but the shape of the distribution in the lower intensity region remains substantially the same
Solution Approach 1:
The patent applies local quality by treating different regions of the vibration intensity distribution differently. The first region (smaller intensity values) is used to calculate the knock reference value to maintain stability and eliminate component variations, while the second region (larger intensity values) is excluded from this calculation to prevent divergence. This localized approach allows the system to leverage the stable lower-intensity region while ignoring the divergent higher-intensity region, resolving the contradiction between distribution shape stability and reference value stability.
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
Enables accurate detection of knocking even under conditions of divergence, with a knock reference value set close to that during no knocking, eliminating the influence of component variations and improving detection accuracy.
Implementation Method 1
a vibration intensity or magnitude calculated from an output signal of a knock sensor
Data Source
AI summary
In determining a knock of an engine, a vibration intensity is calculated by logarithm-transforming a peak value or an integral value of an output signal of a knock sensor. Further, a central value VMED of a vibration intensity distribution is calculated, and also a standard deviation σ in a region where the vibration intensity is smaller than this central value VMED is calculated. A vibration intensity reference value VIB is calculated as VMED−u×σ, thereby setting the vibration intensity reference value VIB to be close to a minimum of the vibration intensity distribution. Further, a knock reference value KCK is set by adding a predetermined value K to the vibration intensity reference value VIB. The vibration intensity detected by the knock sensor is compared with the knock reference value KCK to determine presence/absence of a knocking.