Magnetic Sensor Fault Signaling via Pulse Pattern Encoding
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Solution Overview
Problem
Magnetic sensors in automotive systems face challenges in independently signaling possible faults to the Electronic Control Unit (ECU) while maintaining the ability to transmit profile information of a rotating magnet wheel, as per safety standards like ISO 26262, without compromising the transmission of profile data.
Innovation Solution
The magnetic sensor is configured to transmit safe-state and diagnosis information via specific pulse patterns during designated time periods, such as reference zone gaps or tooth gaps, allowing it to independently signal faults without interfering with the transmission of profile information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the magnetic sensor transmits fault information independently to the ECU, then the safety level of the automotive system is improved, but the device complexity increases due to additional transmission mechanisms
Solution Approach 1:
The patent combines fault information transmission with the existing profile information transmission by encoding fault status in the pulse patterns of the same output signal. The magnetic sensor uses different pulse patterns (e.g., modified pulse widths, frequencies, or sequences) to convey both wheel profile data and fault status through a single output channel, eliminating the need for separate transmission mechanisms and reducing device complexity while maintaining high safety levels
Solution Approach 2:
The output signal of the magnetic sensor is designed to serve multiple functions simultaneously: it transmits both the wheel profile information and the fault status information through a single communication channel. The ECU is configured to interpret different aspects of the same signal for different purposes, making the transmission system universal and multi-functional without requiring additional hardware components
2Loss of information
If the magnetic sensor transmits fault information during designated time periods, then the interference with profile information transmission is reduced, but the loss of time for fault signaling occurs
Solution Approach 1:
The patent implements periodic transmission of fault information by encoding it in specific pulse patterns that occur at regular intervals within the rotation cycle. The ECU is trained to recognize these periodic patterns as fault indicators, allowing fault information to be transmitted continuously over time without requiring dedicated transmission windows, thus eliminating time loss while minimizing interference through pattern recognition
3Measurement precision
If the magnetic sensor uses specific pulse patterns for fault information, then the clarity of fault signaling is improved, but the difficulty of detecting and measuring increases due to pattern recognition complexity
Solution Approach 1:
The patent applies local quality by introducing distinct, localized modifications to specific portions of the pulse signal rather than changing the entire signal structure. For example, only certain pulse widths or specific pulse positions are modified to indicate fault conditions, while the rest of the signal maintains its original profile information structure. This localized approach improves fault detection clarity while keeping the overall pattern recognition relatively simple for the ECU
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
Enables the magnetic sensor to effectively transmit fault information to the ECU in real-time, ensuring high safety levels for fail-safe automotive systems without compromising the ability to transmit profile information of the magnet wheel.
Implementation Method 1
A magnetic sensor may sense a magnetic field produced or distorted by a rotating magnet wheel
Data Source
AI summary
A magnetic sensor may sense a magnetic field during a rotation of a wheel. The sensed magnetic field may represent a profile of the wheel during the rotation. The magnetic sensor may determine, based on the sensed magnetic field, information associated with a possible fault of at least one of the magnetic sensor or the wheel. The magnetic sensor may transmit a first set of output pulses corresponding to the profile of the wheel during the rotation. The first set of output pulses may be transmitted during the rotation of the wheel. The magnetic sensor may transmit a second set of output pulses that corresponds to the information associated with the possible fault.