Engine Synchronization Tolerance Adjustment for Stalling
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Solution Overview
Problem
Existing synchronization methods for internal combustion engines fail to accurately determine engine position during reverse rotation and stalling phases, leading to erroneous edge detection and potential engine damage or malfunction.
Innovation Solution
A synchronization method that reduces the tolerance range for comparing time signatures of detected edges with theoretical signatures when engine speed drops below a threshold, enhancing accuracy during stalling phases and ensuring effective resynchronization upon engine restart.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a fixed tolerance range is used for comparing time signatures during synchronization, then the synchronization method is simple to implement, but it produces erroneous edge detection during engine stalling and reverse rotation
Solution Approach 1:
The patent applies dynamics by making the tolerance range variable rather than fixed. The tolerance range is dynamically adjusted based on engine operating conditions: a first tolerance range is used during normal operation, while a second, narrower tolerance range is applied during stalling phases detected by the processor. This dynamic adaptation resolves the contradiction by maintaining high detection accuracy during critical stalling conditions without requiring complete redesign of the synchronization system.
Solution Approach 2:
The patent implements parameter changes by modifying the tolerance range parameter according to engine state. The system changes the tolerance parameter from a default value during normal operation to a reduced value when stalling is detected, based on analysis of camshaft position data and edge detection patterns. This parameter adjustment allows the system to maintain simplicity while improving accuracy during problematic operating conditions.
2Reliability
If the tolerance range is reduced during stalling phases, then edge detection accuracy improves, but the system requires complex logic to detect and respond to stalling conditions
Solution Approach 1:
The patent employs feedback mechanisms where the processor continuously monitors camshaft position data and edge detection results to detect stalling conditions. When stalling is detected through analysis of inconsistent edge timing and position data, the system provides feedback by adjusting the tolerance range parameter. This feedback loop enables reliable synchronization during stalling without requiring complex external control systems, as the stalling detection and response are integrated into the existing synchronization processor.
3Ease of operation
If conventional synchronization methods are used during reverse rotation, then the system operates with standard logic, but erroneous forward rotation detection occurs
Solution Approach 1:
The patent applies asymmetry by implementing different tolerance ranges for different operational states. The system uses a first tolerance range for normal forward rotation and a second, asymmetrically different tolerance range for stalling and reverse rotation conditions. This asymmetric approach allows the system to maintain simple standard operation while accurately detecting rotation direction and state, preventing erroneous forward rotation detection during reverse operation.
Data Source
AI summary
Disclosed is a method for synchronizing an engine including a camshaft and a position sensor for sensing the position of the camshaft. The method includes, for each detected tooth edge: computing a time signature of the detected edge; comparing the time signature of the detected edge with a set of theoretical signatures of edges of the target including a theoretical signature for each edge of the target, the comparison being implemented through a tolerance; and generating a synchronization or synchronization fault signal as a function of the result of the comparison. When the engine speed drops below a predetermined threshold, the tolerance adopted for comparing the time signature of a detected edge with the theoretical signature of an edge of the target is reduced in relation to the tolerance adopted for the same comparison before the engine speed drops below the threshold.