Variable Reluctance Sensor Interface with Clearing Signal Generator
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Solution Overview
Problem
Variable reluctance sensors (VRSs) face inaccuracies in determining the angular position and speed of rotating objects due to noise spikes, particularly from ignition events, leading to erroneous transitions and synchronization issues in detect signal generation, which can result in incorrect engine timing and potential engine damage.
Innovation Solution
A VRS interface with a clearing signal generator that generates a clearing signal to prevent unwanted transitions caused by noise, either by blanking during anticipated noise events or resetting after the event to ensure accurate detection of tooth edges, thereby improving the accuracy of position and motion determinations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If noise filtering is applied to eliminate ignition event interference, then measurement precision improves, but response time increases due to signal blanking periods
Solution Approach 1:
The system performs preliminary actions by predicting ignition event timing based on detected tooth positions and engine timing parameters. The clearing signal is generated in advance of actual ignition events, allowing the system to prepare for and filter noise proactively rather than reactively, thus minimizing response time loss while maintaining measurement precision.
Solution Approach 2:
The system uses feedback from detected tooth edges and engine timing parameters to dynamically adjust the clearing signal timing and duration. This feedback mechanism allows the system to optimize the balance between noise filtering effectiveness and response time, ensuring that blanking periods are applied only when necessary and for the minimum required duration.
2Reliability
If clearing signals are generated to prevent erroneous transitions during ignition events, then reliability improves, but device complexity increases due to additional signal generation and timing control circuitry
Solution Approach 1:
The clearing signal generator is designed to perform multiple functions: it generates clearing signals for noise filtering, provides timing synchronization for the detection circuit, and can be integrated with existing engine control unit functions. This multi-functionality reduces the need for separate dedicated components, thereby limiting the increase in device complexity while maintaining improved reliability.
Solution Approach 2:
The system uses its own detected tooth position information and existing timing parameters to generate the clearing signals, rather than requiring external synchronization sources or additional sensors. This self-service approach leverages already-available system data, reducing the need for additional complex circuitry while ensuring reliable noise filtering.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The proposed solution reduces the probability of erroneous transitions and missed transitions in the detect signal, enhancing the accuracy of position and motion determinations, ensuring proper engine timing and preventing potential engine damage.
Implementation Method 1
each tooth passing by the VRS changes the magnetic flux which is converted to an electrical voltage induced in the coil
Implementation Method 2
The VRS typically includes a coil and biasing magnet positioned near the toothed wheel
Implementation Method 3
Variable reluctance sensors (VRSs) are commonly used to measure the angular position and/or speed of a moving or rotating ferromagnetic object
Data Source
AI summary
The embodiments described herein include systems with a variable reluctance sensor (VRS) interface and methods of their operation. Embodiments of VRS interfaces include a clearing signal generator configured to generate a clearing signal corresponding with the timing of a noise event. The clearing signal may be configured to clear a post-processing circuit.