Crankshaft Sensor Inverted Connection Detection
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Solution Overview
Problem
Crankshaft sensors can experience connection errors during mounting or replacement, leading to inverted wire connections, which result in angular position detection errors and incorrect engine orientation.
Innovation Solution
A method and device that diagnose inverted connections by calculating a ratio of tooth times using the formula Ri=(Ti−1)2/(Ti*Ti−2) and comparing it with low and high thresholds to differentiate between correct and inverted connections, utilizing the distinct behavior of tooth time ratios in correctly and incorrectly connected sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the crankshaft sensor is used to determine angular position during engine start-up, then the engine control can introduce fuel at the correct orientation, but an inverted wire connection causes angular offset in the detection of tooth and turn marker
Solution Approach 1:
The patent applies preliminary action by performing inversion detection during engine start-up before normal operation begins. The method acquires signals and calculates tooth time ratios during the start-up phase, allowing the system to identify connection errors before they affect fuel injection timing and engine operation
Solution Approach 2:
The patent implements feedback by continuously monitoring the tooth time ratio and comparing it against threshold values. The system calculates Ri=(Ti-1)²/(Ti×Ti-2) for each detected tooth and compares the ratio with predetermined thresholds to determine whether an inverted connection exists, providing real-time feedback on connection status
2Ease of operation
If wire connection is inverted during mounting or replacement, then the sensor can still provide a signal, but the observed signal is inverted causing detrimental angular offset
Solution Approach 1:
The patent applies self-service by enabling the sensor system to automatically detect and diagnose its own connection status. The method uses the sensor's own output signals to calculate tooth time ratios and determine whether wires are inverted, allowing the system to self-diagnose connection errors without external intervention
Solution Approach 2:
The patent introduces an intermediary diagnostic parameter - the tooth time ratio Ri - that mediates between the raw sensor signals and the final angular position determination. This intermediate ratio provides information about connection status that is separate from the normal position measurement, allowing the system to detect inversion without affecting the primary measurement function
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
Effectively detects inverted connections by identifying the ratio behavior, allowing for accurate determination of crankshaft angular position and preventing detrimental measurement errors, with thresholds judiciously determined to differentiate between correct and inverted sensor states.
Implementation Method 1
a magnetic sensing element, rigidly connected to a frame, that can detect the presence and/or the absence of matter, and placed in proximity to the periphery of said toothed wheel
Implementation Method 2
Such a sensing element measures, and provides, across two terminals/wires, a potential difference indicative of an electrical field forming in the sensing element
Data Source
AI summary
A method for diagnosing an inversion of a crankshaft sensor includes the following steps: acquiring a signal by way of the crankshaft sensor, at each detection of a tooth, determining a tooth time elapsed since the previous tooth detection, at each detection of a tooth, calculating a ratio Ri of the tooth times according to the formula Ri=(Ti−1)2/(Ti*Ti−2), where Ri is the ratio, Ti is the last tooth time, Ti−1 is the penultimate tooth time, and Ti−2 is the tooth time preceding the penultimate tooth time, comparing the ratio Ri with a low threshold Sb, indicative of a turn marker, and a high threshold Sh, indicative of an absence of inversion, a ratio Ri between the two thresholds Sb, Sh being indicative of an inversion.