Ignition Timing Control Using Vibration Waveform Correlation
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Solution Overview
Problem
Existing ignition timing control devices for internal combustion engines are susceptible to inaccuracies in knocking determination due to independent statistical and waveform processing methods, leading to potential improper ignition timing adjustments that can result in insufficient output or increased knocking occurrences, especially under varying load conditions.
Innovation Solution
An ignition timing control device that includes a knock magnitude calculating portion, a control portion, a waveform detecting portion, a memory for storing standard vibration waveforms, and correcting and prohibiting portions to adjust the determination value based on detected vibration waveforms and load conditions, thereby distinguishing between knocking and noise components and optimizing ignition timing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If independent statistical processing and waveform processing are used for knocking determination, then the device can perform knocking detection, but the accuracy of each determination method is not improved and noise components cause deterioration of accuracy
Solution Approach 1:
The patent merges statistical processing and waveform processing into a unified determination framework. The waveform processing unit analyzes the shape characteristics of vibration signals, while the statistical processing unit evaluates magnitude distributions. Both processes work together to determine knocking, with the waveform analysis helping to filter out noise components that would otherwise degrade accuracy. This combined approach resolves the contradiction by making the system robust against noise while maintaining high determination accuracy.
2Reliability
If ignition timing is retarded when knocking is detected, then knocking is suppressed, but engine output becomes insufficient depending on the load
Solution Approach 1:
The patent applies local quality by making the ignition timing control strategy dependent on the engine load condition. When the load is low, the determination value is corrected to be more sensitive, allowing for greater ignition timing retard to suppress knocking. When the load is high, the determination value is not corrected, maintaining a higher threshold that prevents excessive retard and preserves engine output. This load-dependent approach resolves the contradiction by applying different control qualities to different operating conditions.
3Adaptability or versatility
If the determination value is corrected based on vibration magnitude, then the control adapts to engine conditions, but improper correction under varying load conditions leads to insufficient output or increased knocking
Solution Approach 1:
The patent implements dynamics by making the determination value adaptive to engine operating conditions through load-dependent correction. The correcting portion dynamically adjusts the determination value based on the relationship between vibration magnitude and engine load. When load is low, the determination value is corrected to reflect the lower threshold for knocking detection. When load is high, the determination value remains uncorrected to maintain appropriate sensitivity. This dynamic adjustment resolves the contradiction by adapting the control parameters to match the physical conditions of engine operation.
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 device accurately determines knocking occurrences and adjusts ignition timing to prevent knocking while maintaining engine output, by correcting the determination value based on vibration waveforms and load conditions, thus ensuring proper ignition timing control.
Implementation Method 1
a knock magnitude calculating portion for calculating knock magnitude related to magnitude of vibration due to knocking based on magnitude of vibration occurring in the internal combustion engine
Data Source
AI summary
An engine ECU executes a program including the steps of: comparing a vibration waveform of an engine and a knock waveform model stored in advance to calculate a correlation coefficient K; prohibiting correction when a correction prohibiting condition of a determination value V(KX) is satisfied, the determination value V(KX) compared with a knock magnitude N calculated from the correlation coefficient K so as to control the ignition timing; and correcting the determination value V(KX) based on a magnitude value LOG(V) calculated from a magnitude V of vibration in an ignition cycle in which the correlation coefficient K greater than a threshold value K(1) is calculated when the correction prohibiting condition of determination value V(KX) is not satisfied. The correlation coefficient K is calculated as a smaller value when the vibration waveform includes a waveform of vibration of a noise component as compared with that when the vibration waveform does not include it.