Median-Based Cylinder Control for Combustion Engine Stability
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Solution Overview
Problem
Existing methods for cylinder equalization in internal combustion engines are vulnerable to outliers and inaccurate signals, leading to unstable control and uneven performance across cylinders.
Innovation Solution
Using the median of cylinder-specific signals as the setpoint for combustion parameter adjustment, rather than the arithmetic mean, to create a more robust and stable control system, with adjustments made to fuel quantity and ignition timing based on deviations from the median target.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the arithmetic mean of cylinder signals is used as the target value, then the control system is simple to implement, but the target value becomes unstable and inaccurate due to outliers and sensor errors
Solution Approach 1:
The patent changes the statistical parameter used for target value calculation from arithmetic mean to median. This parameter change makes the target value robust against outliers and measurement errors while maintaining computational simplicity. The median is calculated by sorting the cylinder signals and selecting the middle value, which inherently filters out extreme values without requiring complex algorithms.
2Ease of manufacture
If the arithmetic mean of cylinder signals is used as the target value, then the calculation is straightforward, but the control stability deteriorates when outliers or corrupted signals are present
Solution Approach 1:
The patent replaces the arithmetic mean parameter with the median parameter for target value determination. This change maintains ease of calculation through simple sorting and selection operations while dramatically improving control stability by eliminating the sensitivity to outliers and corrupted signals that plagues the arithmetic mean approach.
3Device complexity
If global control of combustion parameters is used, then the control system is simple, but cylinder performance becomes uneven due to individual cylinder variations
Solution Approach 1:
The patent implements local quality adjustment by determining individual cylinder offset values based on the deviation of each cylinder's signal from the median target value. Each cylinder receives customized fuel quantity or ignition timing adjustments rather than uniform global control, thereby improving performance uniformity while maintaining overall system simplicity through the robust median-based target value.
Data Source
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AI summary
The method involves detecting a cylinder-specific signal of each cylinder, such as of cylinder internal pressure, cylinder exhaust gas temperature, nitrogen oxide emissions or combustion-air ratio, and forming a set value from the signals of the cylinder. A combustion parameter of the corresponding cylinder is adjusted in dependence on the deviation of a signal from the set value. The signal is tracked to the target value, where the median of the signals is formed as the set value.