Camshaft Sensor Engine Synchronization via Ratio Comparison
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Solution Overview
Problem
Existing methods for synchronizing internal combustion engines rely on crankshaft sensors, which fail to provide effective synchronization when malfunctioning, leading to delays in engine startup and potential combustion issues due to the need for alternative methods that require multiple cam edge measurements and tolerance calculations.
Innovation Solution
A method that determines the synchronization of an internal combustion engine using camshaft sensor data by calculating and comparing actual ratios of cam edge times and angles within defined tolerance windows, allowing for quick synchronization without crankshaft sensor data, even when only five cam edges are detected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the crankshaft sensor is used for synchronization, then the piston position can be estimated, but the method fails when the crankshaft sensor malfunctions
Solution Approach 1:
The patent introduces a camshaft sensor as an intermediary device to determine piston position and engine phasing when the crankshaft sensor fails. The camshaft sensor detects camshaft rotation and uses this information to calculate piston position through geometric relationships between camshaft and crankshaft, providing a backup synchronization method that maintains system reliability without requiring the crankshaft sensor to be functional.
2Reliability
If alternative methods are used when crankshaft sensor fails, then synchronization can still be achieved, but the synchronization time is delayed
Solution Approach 1:
The patent performs preliminary calculations of piston position and engine phasing based on camshaft sensor data before combustion can occur. By continuously monitoring camshaft rotation and pre-calculating the corresponding crankshaft positions using geometric models, the system prepares synchronization information in advance, reducing the time delay associated with alternative synchronization methods when the crankshaft sensor is unavailable.
3Measurement precision
If multiple cam edge measurements are required, then accurate phasing can be determined, but the complexity of the synchronization process increases
Solution Approach 1:
The patent changes the parameters used for synchronization from direct crankshaft position measurements to camshaft rotation angle measurements. By using the camshaft sensor to detect camshaft rotation and converting this information to equivalent crankshaft positions through geometric calculations, the system achieves accurate phasing determination while simplifying the overall process to rely on a single sensor type and straightforward mathematical transformations rather than complex multi-sensor coordination.
Data Source
AI summary
A method for synchronizing an internal combustion engine includes: a) a first step of acquiring, by the camshaft sensor, signals corresponding to at least five cam edges x; b) a second step of determining the value, from the camshaft signal, of a first, second and third actual ratio; c) a third step of establishing, for each actual value ratio obtained in b), a list of possible cam edges x by comparing the values of the first, second and third actual ratios, respectively, with a tolerance window corresponding to a value of a first, second or third theoretical ratio for a given cam edge x, each weighted by a tolerance factor k; and d) a fourth step of determining the cam edge x seen by the camshaft sensor, the cam edge actually seen by the sensor corresponding to the cam edge x common to the three lists established in c).