PCB Liquid Ingress Sensing for Electronic Control Housings
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Solution Overview
Problem
Existing electronic control devices for mechanical systems, such as vehicle braking systems, are vulnerable to liquid ingress, which can cause electrical shorts, malfunctions, overheating, and potential fires, and existing solutions like waterproofing and separate detection devices require design changes and are not timely in response.
Innovation Solution
A liquid detection device integrated into the circuit board of the electronic control device, using electrodes and sensors to measure resistance changes and automatically cut off power supply when liquid is detected, without altering the device's design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If waterproofing treatment or separate liquid detection device is installed, then reliability is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The liquid detection function is merged with the existing circuit board by integrating electrodes directly into the circuit board structure. This eliminates the need for separate detection devices and waterproofing treatments, reducing overall device complexity while maintaining liquid detection capability. The electrodes are formed as conductive patterns on the circuit board, utilizing existing manufacturing processes.
Solution Approach 2:
The circuit board itself serves the dual function of electrical connectivity and liquid detection. The electrodes integrated into the circuit board allow the board to detect liquid ingress autonomously without requiring external detection devices. The control unit, already present for brake control, is extended to monitor electrode resistance changes and trigger protective actions.
2Reliability
If conventional waterproofing or separate detection device is used, then reliability is improved, but manufacturing cost increases
Solution Approach 1:
The liquid detection functionality is combined with the existing circuit board manufacturing process. electrodes are created using standard PCB fabrication techniques (copper tracing, solder masking), eliminating the need for separate detection device assembly and reducing manufacturing costs. The integration utilizes existing materials and processes already present in brake control unit production.
3Reliability
If fuse or thermal fuse is used for short circuit protection, then safety is improved, but response time is delayed
Solution Approach 1:
The electrode-based detection system performs preliminary detection of liquid ingress before electrical short circuit occurs. By monitoring resistance changes between electrodes, the system identifies liquid presence early and can trigger preventive actions (warning signals, controlled shutdown) before damage happens, rather than waiting for fuse activation after short circuit damage has already occurred.
4Stability of the object's composition
If circuit board is tightly fixed in housing, then structural stability is improved, but vulnerability to liquid damage increases
Solution Approach 1:
The integrated electrodes provide continuous feedback about liquid presence in the housing. When liquid is detected through resistance changes, the control unit receives feedback and can take protective actions such as shutting down electrical components or issuing warnings. This feedback mechanism allows the tightly fixed circuit board structure to be protected through active monitoring and response.
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
Prevents electrical shorts and overheating by detecting liquid ingress and cutting power supply, reducing the risk of fires and mechanical damage, while maintaining the device's original design and reducing manufacturing costs.
Implementation Method 1
a sensor which is formed on the other side of the circuit board... the sensor includes a first electrode which is formed on the circuit board and a second electrode which is spaced apart from the first electrode by a predetermined distance
Data Source
AI summary
A device for detecting a liquid introduced into a housing of an electronic control device is provided. The device for detecting a liquid introduced into a housing of an electronic control device according to an exemplary embodiment of the present disclosure is a device for detecting a liquid introduced into the housing of an electronic control device including a housing, a circuit board installed in the housing and an electronic controller mounted on one side of the circuit board and connected to an operator located outside the housing to control the operator, and the device may include a sensor which is formed on the other side of the circuit board; and a first switch for cutting off power supplied to the electronic controller from a power source, wherein the sensor includes a first electrode which is formed on the circuit board and a second electrode which is spaced apart from the first electrode by a predetermined distance, wherein the first electrode includes a linear first sensing pattern extending in a first direction, and wherein the second electrode includes a linear second sensing pattern extending in the first direction.