HEV Magnetic Speed Sensor Offset Algorithm for Crankshaft Disengagement
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Solution Overview
Problem
Current magnetic speed sensors are not designed to operate effectively in hybrid electric vehicle (HEV) environments, leading to incorrect pulse generation and misinformation when the crankshaft is disengaged, causing loss of sync with the engine management system.
Innovation Solution
A magnetic sensor module that measures a magnetic field oscillating between extrema, featuring a sensor circuit that generates a pulsed output signal and updates a switching threshold using an offset update algorithm, with selective enabling and disabling based on signal characteristics to prevent incorrect updates during crankshaft disengagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the offset update algorithm continuously updates the switching threshold based on measurement signal characteristics, then the speed sensor adapts to signal variations and maintains accuracy under normal operation, but during crankshaft disengagement the sensor incorrectly updates the offset based on random vibrations, leading to wrong pulse generation and loss of sync
Solution Approach 1:
The offset update algorithm is made dynamic by enabling it during normal crankshaft rotation when speed exceeds a threshold, and disabling it during crankshaft disengagement when vibrations cause false signals. This conditional activation based on operational state allows the system to adapt when needed while preventing incorrect updates when the crankshaft is free-moving, resolving the contradiction between measurement precision and reliability.
Solution Approach 2:
The system uses feedback from the measurement signal characteristics (frequency, amplitude, pattern recognition) to determine whether the crankshaft is rotating normally or disengaged. This feedback mechanism controls the offset update algorithm's activation, ensuring updates only occur when valid crankshaft rotation is detected, thus maintaining both accuracy and reliability.
2Adaptability or versatility
If the speed sensor operates in HEV environment with crankshaft disengagement, then the vehicle can run on electric propulsion, but the free crankshaft rotates randomly due to vibrations causing maximum and minimum events that trigger incorrect offset updates
Solution Approach 1:
The offset update algorithm acts as an intermediary between the raw measurement signal and the output pulses to the ECU. By selectively enabling/disabling this intermediary based on crankshaft state detection, the system filters out misinformation from random vibrations during disengagement while preserving valid speed information during normal operation, enabling HEV compatibility without information loss.
3Speed
If the switching threshold is continuously adapted to follow signal variations, then the sensor maintains sensitivity to speed changes, but during disengagement the threshold adapts to vibration patterns generating too many forward or backward pulses
Solution Approach 1:
The system applies preliminary anti-action by detecting crankshaft disengagement conditions in advance and preemptively disabling the offset update algorithm before wrong pulses can be generated. This prevents the switching threshold from adapting to vibration patterns, maintaining speed detection sensitivity during normal operation while blocking harmful adaptations during disengagement.
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 solution ensures accurate speed measurement and prevents incorrect pulse generation, maintaining system sync even when the combustion engine is off, by disabling offset updates during crankshaft disengagement, thus improving sensor reliability in HEV environments.
Implementation Method 1
magnetic sensor module configured to measure a magnetic field whose magnitude oscillates between a first extrema and a second extrema
Data Source
AI summary
Magnetic field sensors and sensing methods are provided. A magnetic sensor module is configured to measure a magnetic field whose magnitude oscillates between a first extrema and a second extrema. The magnetic sensor module includes a magnetic sensor configured to generate measurement values in response to sensing the magnetic field, and a sensor circuit. The sensor circuit is configured to generate a measurement signal based on the measurement values, adjust an offset of the measurement signal according to an offset update algorithm and a first characteristic of the measurement signal, generate a pulsed output signal having pulses that are generated based on the adjusted measurement signal crossing the switching threshold, and selectively enable and disable the offset update algorithm based on a second characteristic of the measurement signal.