Crankshaft Torsion Compensation in Internal Combustion Engines
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Solution Overview
Problem
Existing methods for controlling internal combustion engines fail to accurately determine crank angle deviations for individual cylinders, leading to inefficiencies and inaccuracies in crank angle-dependent control signals due to limited consideration of torsional twisting, which affects power output and efficiency.
Innovation Solution
A method that determines cylinder-individual crank angle deviations for each position of the crankshaft, allowing for crank angle-dependent signal corrections by using a substitute function that calculates torsion characteristics based on firing order, spacing, and material properties, enabling precise adjustments for each cylinder throughout the engine cycle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If cylinder-individual corrections for crank angle signals are provided using performance maps of correction values, then the power output and efficiency of the internal combustion engine are improved, but the complexity of the control system increases due to storing and processing multiple correction values for each cylinder
Solution Approach 1:
The patent segments the crankshaft into multiple measurement sections (first, second, third sections) with individual angle position sensors, allowing localized measurement of crank angle positions. This segmentation enables cylinder-individual correction values to be determined more efficiently without requiring complex global corrections for the entire crankshaft, thereby improving productivity while managing control system complexity.
Solution Approach 2:
The patent introduces an intermediary calculation approach where a substitute function is used to calculate expected crank angle positions based on nominal values and measured deviations from intermediate measurement sections. This intermediary method simplifies the determination of correction values compared to direct measurement of all crank angle positions, reducing control system complexity while maintaining improved power output and efficiency.
2Device complexity
If only local twisting or overall twisting of the crankshaft is determined, then the measurement and control processes are simplified, but the accuracy of crank angle information for individual cylinders is insufficient
Solution Approach 1:
The crankshaft is divided into multiple measurement sections (first, second, third sections) with individual angle position sensors placed at each section. This segmentation enables simultaneous determination of both local twisting (between adjacent sections) and overall twisting (across the entire crankshaft), providing accurate crank angle information for individual cylinders while maintaining manageable measurement and control processes through modular sensor placement and processing.
Solution Approach 2:
The patent adds a temporal dimension to the measurement process by continuously monitoring crank angle positions at multiple sections throughout the engine cycle. This multi-dimensional approach (spatial segmentation across multiple sections plus temporal monitoring) enables accurate determination of crank angle deviations for individual cylinders at different crankshaft positions, transforming the measurement from a single-point snapshot to a comprehensive multi-point continuous process.
3Device complexity
If crank angle information is ascertained only for a single selected crankshaft angle position, then the control system is simpler to implement, but the precision of timing and measurement alignment for all positions is compromised
Solution Approach 1:
Instead of measuring crank angle at a single position, the patent segments the measurement process across multiple crankshaft sections (first, second, third sections) with individual sensors at each section. This segmentation enables determination of crank angle information for all crankshaft positions by combining measurements from multiple sections, achieving precise timing and measurement alignment for the entire engine cycle while maintaining relatively simple control system implementation through standardized sensor placement and processing.
Solution Approach 2:
The patent applies preliminary corrections to crank angle signals by determining correction values based on measurements from multiple sections before using these corrected values for control decisions. This preliminary action of correcting crank angle deviations based on multi-section measurements ensures accurate timing and measurement alignment for all positions throughout the engine cycle, rather than relying on uncorrected single-point measurements.
Data Source
AI summary
A method of controlling an internal combustion engine having a plurality of cylinders, in particular a stationary internal combustion engine, wherein actuators of the internal combustion engine are actuable in crank angle-dependent relationship and/or sensor signals of the internal combustion engine can be ascertained in crank angle-dependent relationship,for compensation of a torsion of a crankshaft, by which torsion deviations in the crank angle occur between a twisted and an untwisted condition of the crankshaft,wherein for at least two of the cylinders a cylinder-individual value of the angle deviation is ascertained and the crank angle-dependent actuator or sensor signals are corrected in dependence on the detected angle deviation.