Engine Synchronization Using Learned Camshaft Edge Positions
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Solution Overview
Problem
Current engine synchronization methods are slow due to the need for a wide tolerance to account for mechanical tolerances, leading to delayed engine start times and potential edge confusion when rising and falling edges of the camshaft target are close, which prevents accurate identification.
Innovation Solution
A method that uses a learning process to determine the actual positions of the camshaft edges during initial synchronizations, allowing for a smaller tolerance threshold to be set, reducing synchronization time and preventing edge confusion, by averaging edge positions over multiple synchronizations and recording them for future use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a wide tolerance threshold is used to account for mechanical tolerances during engine synchronization, then the reliability of edge detection is improved, but the synchronization time increases significantly
Solution Approach 1:
The patent applies preliminary action by performing multiple test synchronizations before the actual engine operation to learn and store the precise positions of camshaft target edges. During these preliminary synchronizations, the system detects and records the actual positions of rising and falling edges with wide tolerance, then stores these learned positions in memory. When the engine needs to start, the system retrieves these pre-stored positions and uses them with a narrow tolerance threshold, achieving both high reliability and fast synchronization.
2Productivity
If a narrow tolerance threshold is used to reduce synchronization time, then the productivity is improved, but the risk of edge misidentification increases due to mechanical tolerances
Solution Approach 1:
The patent implements feedback by using the results of preliminary synchronizations to inform and adjust the synchronization process for actual operation. During preliminary synchronizations, the system detects edge positions and feeds this information back by storing it in memory. This learned feedback is then used during subsequent engine starts to guide the synchronization process with high precision, allowing the use of narrow tolerance thresholds without risking misidentification of edges.
3Device complexity
If the rising and falling edges of the camshaft target are positioned close together, then the device complexity is reduced, but the difficulty of detecting and measuring individual edges increases
Solution Approach 1:
The patent applies copying by creating a digital replica of the camshaft target edge positions through the learning process. Instead of relying on physical separation of edges to make them distinguishable, the system detects and stores precise copies of edge positions in memory during preliminary synchronizations. This digital copy allows the system to identify and distinguish even closely-spaced edges during operation by comparing sensor signals against the stored reference positions, overcoming the physical constraint of edge spacing.
Data Source
AI summary
Disclosed is a method for synchronizing a combustion engine of a motor vehicle, including the steps of detection of the reference position of a first toothed wheel during a rotation of the crankshaft from the measurements sent by a first measuring sensor, detection of rising and falling edges of the teeth of a second toothed wheel during a concomitant rotation of the camshaft from the measurements sent by a second measuring sensor, identification of the detected edges with a first tolerance threshold on the angular position of the camshaft from recorded positions of the edges to synchronize the engine, the recorded positions being predetermined by learning from theoretical positions with a second tolerance threshold on the angular position of the camshaft, the first tolerance threshold being less than the second tolerance threshold, and synchronization of the engine from the identified edges of the teeth of the second toothed wheel.