Engine Angular Position Determination via Crankshaft Camshaft Sensor Synchronization
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Solution Overview
Problem
Existing engine synchronization methods fail to accurately determine the angular position in reverse rotation, leading to potential fuel injection errors and adverse engine effects.
Innovation Solution
A method using a crankshaft sensor with a toothed wheel and a camshaft sensor to detect 'missing tooth' events, switching between fast and slow modes to determine the angular position, ensuring accurate synchronization by verifying events within a tolerance window and adjusting based on direction changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If fast mode synchronization is used to quickly determine engine angular position, then productivity is improved, but reliability deteriorates because the system cannot detect reverse rotation and may synchronize incorrectly
Solution Approach 1:
The system dynamically switches between fast mode and slow mode based on detected conditions. Fast mode is used for normal operation to maintain high productivity, while slow mode is activated when reverse rotation is detected to ensure reliable synchronization. This dynamic adaptation resolves the contradiction by allowing the system to optimize for speed when safe and for accuracy when risk of reverse rotation exists.
Solution Approach 2:
The system uses feedback from tooth event timing and camshaft-crankshaft synchronization status to detect reverse rotation conditions. When the timing of tooth events deviates from expected patterns or when camshaft position does not match expected relationship with crankshaft, the system identifies reverse rotation and switches modes accordingly, preventing incorrect synchronization while maintaining fast operation during normal conditions.
2Reliability
If the system continuously monitors for reverse rotation using slow mode, then reliability is improved, but productivity deteriorates due to increased synchronization time
Solution Approach 1:
The system dynamically adjusts its monitoring intensity based on operational context. During normal forward rotation, fast mode provides sufficient reliability with minimal time penalty. When reverse rotation conditions are detected through timing analysis or camshaft-crankshaft relationship verification, the system transitions to slow mode to ensure accurate detection, thus maintaining high productivity while providing reliable reverse rotation detection when needed.
Solution Approach 2:
The system skips the time-consuming slow mode synchronization process during normal operation by using fast mode, which quickly determines engine angular position. However, the system remains vigilant for reverse rotation conditions and will immediately switch to slow mode if such conditions are detected, effectively rushing through normal synchronization while maintaining the capability for thorough verification when necessary.
Data Source
AI summary
A method for determining the angular position of an engine by a crankshaft sensor and a camshaft sensor. The method includes production by the crankshaft sensor of a revolution event, determination of the angular position of the camshaft by identifying the start-of-tooth and end-of-tooth events following the revolution event, in rapid mode, over at most one revolution of the crankshaft, if a no tooth event occurs after the revolution event and if the determination of the angular position of the camshaft fails, the method continues with a step of determining the angular position of the camshaft by identification, in slow mode, over at least two crankshaft revolutions.