Crankshaft Sensor Signal Encoding for Malfunction Diagnosis
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Solution Overview
Problem
Crankshaft sensors in motor vehicles fail to communicate malfunctions such as air gap defects, alignment issues, and radial runout, leading to inaccurate determination of speed and direction of rotation.
Innovation Solution
The method involves generating additional pulse durations in the signal output to produce a binary coding that represents abnormal magnetic field measurements, allowing processing means to diagnose malfunctions by comparing measured values with predetermined threshold values and generating specific pulse durations to indicate malfunctions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sensor delivers only standard digital signals for normal operation, then the system operation is simple, but the sensor cannot communicate malfunctions such as air gap defects, alignment issues, and radial runout
Solution Approach 1:
The patent combines normal measurement signal transmission with malfunction indication into a single integrated signal system. The sensor continues to deliver standard digital signals for normal operation while simultaneously encoding malfunction information in the same signal stream, eliminating the need for separate communication channels or additional hardware components.
Solution Approach 2:
The patent changes the temporal parameters of the digital signal by introducing variable pulse durations. Different pulse duration values encode different malfunction types (e.g., air gap defect, alignment issue, radial runout), allowing the sensor to communicate multiple states using the existing digital signal infrastructure without adding hardware complexity.
2Reliability
If additional hardware components are added to detect and communicate malfunctions, then the diagnosis capability is improved, but the system cost and complexity increase significantly
Solution Approach 1:
The sensor performs self-diagnosis by monitoring its own operational parameters and automatically encoding malfunction information in its output signal. The sensor identifies conditions such as air gap defects, alignment issues, and radial runout through its existing measurement functions and communicates these self-detected malfunctions without requiring external diagnostic hardware.
Solution Approach 2:
The existing digital signal output of the sensor is made multi-functional, serving both as a normal operational measurement signal and as a malfunction communication channel. This universal use of the signal system eliminates the need for separate dedicated diagnostic hardware, reducing manufacturing costs while maintaining comprehensive diagnosis capability.
3Measurement precision
If the sensor monitors multiple parameters continuously, then the measurement precision is improved, but the processing time and computational load increase
Solution Approach 1:
The sensor pre-establishes threshold values and comparison criteria for detecting malfunctions during system setup or calibration. By having these reference values predetermined, the sensor can quickly compare real-time measurements against these thresholds without performing complex real-time calculations, thus maintaining high detection precision while minimizing processing time.
Solution Approach 2:
The sensor implements selective monitoring by focusing on specific critical parameters that indicate malfunctions (such as magnetic field amplitude variations) rather than continuously processing all possible measurement data. This partial action approach maintains sufficient measurement precision for malfunction detection while reducing overall processing time and computational load.
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
This approach enables the processing means to effectively diagnose and communicate malfunctions, such as air gap defects and radial runout, to the central unit, improving the accuracy of speed and direction of rotation measurements without requiring significant hardware changes, only software modifications.
Implementation Method 1
a magnetic field sensor, measuring values of the magnetic field generated by the passage of the teeth in front of said sensor
Data Source
AI summary
The subject of the present invention is a method for communicating a malfunction of a system for measuring speed and direction of rotation of a rotary shaft, said system comprising:a toothed wheel associated with said rotary shaft, called target (14),a magnetic field sensor (10′), measuring values (K, A) of the magnetic field (B, B′, B″) generated by the passage of the teeth (T1, T2 . . . Ti) in front of said sensor (10′) and delivering a signal (S, S′, S″) to processing means 13).According to the invention, the method comprises the following steps:step 1: comparison by the sensor between the measured values and predetermined threshold values of the magnetic field,step 2: if the measured values are below the predetermined threshold values,step 3: generation by the sensor of a coding on the signal, representative of the measured values, to communicate a malfunction of the system to the processing means.