Electronic Control Unit Liquid Detection via PCB Impedance
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Solution Overview
Problem
Current vehicle electrical systems lack the ability to determine the type of substance that has flowed into an electronic control unit, which is crucial for identifying the root cause of liquid inflow and preventing potential vehicle accidents and electrical system defects.
Innovation Solution
An electronic control unit with a housing, a circuit board featuring a first and second pattern, and a controller that monitors voltage changes to determine the type of substance based on reference data stored in memory, using the resistance formed between the patterns to identify the substance and output corresponding information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the Karl Fischer technique is applied for liquid detection, then detection accuracy is improved, but device complexity and cost increase due to additional circuits
Solution Approach 1:
The patent extracts only the essential detection function needed for liquid detection, removing the complex Karl Fischer technique and additional circuits. Instead, it uses a simple resistive component formed by a detection pattern on the PCB that changes resistance when liquid is present, achieving detection with minimal circuitry.
Solution Approach 2:
The patent employs a simple, inexpensive resistive detection pattern on the PCB that can be easily manufactured as part of the standard circuit board. This disposable-like approach uses standard PCB materials and processes, avoiding expensive specialized sensors or additional circuit components.
2Device complexity
If a detection pattern is disposed on the outside of the PCB to detect liquid presence, then device complexity is reduced, but the ability to identify the type of liquid is lost
Solution Approach 1:
The patent changes the detection parameter from simple presence/absence to multi-frequency impedance measurement. By measuring impedance at multiple frequencies, the system captures different electrical characteristics of various liquids, enabling identification of liquid type while still using a simple PCB-integrated detection pattern.
Solution Approach 2:
The patent employs periodic excitation signals at different frequencies to measure the impedance characteristics of the detection pattern. This periodic measurement approach allows the system to extract multiple parameters from the same simple sensor structure, enabling liquid identification without adding complex hardware.
3Ease of operation
If only liquid presence is detected without determining liquid type, then ease of operation is maintained, but the ability to identify root cause of liquid inflow is lost
Solution Approach 1:
The patent implements a feedback mechanism where the measured impedance values at multiple frequencies are compared against reference data stored in memory. This automatic comparison and identification process maintains ease of operation while providing detailed liquid type information for root cause analysis, eliminating the need for manual intervention.
Solution Approach 2:
The system performs self-identification of liquid type by automatically comparing measured impedance characteristics with stored reference data. This self-service capability enables the system to independently determine liquid type and provide diagnostic information without requiring external analysis or complex user interpretation.
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 identification of the substance that has flowed into the electronic control unit, helping to prevent vehicle accidents and electrical system malfunctions by determining the type of liquid and triggering appropriate responses.
Implementation Method 1
utilizing the principle that a resistive component is generated when the detection pattern comes into contact with the liquid
Data Source
AI summary
An electronic control unit includes a housing, a circuit board installed inside the housing and including a first pattern and a second pattern that is spaced apart from the first pattern by a predetermined interval and disposed parallel to the first pattern, and a controller mounted on the circuit board, wherein the controller may control a voltage output of the first pattern based on a determination of an inflow of a substance into the housing, monitor a voltage of a circuit electrically connected to the second pattern while controlling the voltage output of the first pattern, and determine a type of the substance based on data obtained from the monitoring and output corresponding information.