Vehicle Pressure Sensor Venting with Hydrophobic Membrane
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Solution Overview
Problem
Existing pedestrian protection pressure sensor systems face challenges in accurately detecting vehicle impacts while preventing water ingress and maintaining reliable operation under varying pressure conditions.
Innovation Solution
A vehicle pressure sensing system with a housing in fluid communication with a pressure sensor, featuring a connection arrangement for a compressible sensing member and a venting arrangement that includes a filter arrangement allowing gas passage while preventing water, comprising a gas-permeable and water-resistant material with a flow path and drainage aperture, ensuring effective pressure equalization without compromising impact detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If a venting arrangement is provided to allow pressure equalization, then pressure increases during impacts are reduced, but water may ingress through the venting passage causing sensor malfunction
Solution Approach 1:
The patent employs a hydrophobic membrane with microporous structure that allows gas molecules to pass through while blocking water molecules. The membrane's pore size is specifically designed to permit gas permeation for pressure equalization while preventing water ingress, thus resolving the contradiction between pressure relief and water protection.
Solution Approach 2:
The patent utilizes the surface energy parameter of materials by incorporating a hydrophobic coating or selecting hydrophobic materials for the membrane. This parameter change enables the membrane to selectively interact with different substances (gas vs water) based on their molecular properties, allowing gas passage while repelling water.
2Object-affected harmful factors
If the internal space is completely enclosed to protect the sensor, then water ingress is prevented, but pressure equalization under varying temperature and environmental conditions is compromised
Solution Approach 1:
The hydrophobic membrane provides a controlled opening in the enclosure that maintains the sealed protection against water while allowing pressure equalization through its gas-permeable microporous structure. This resolves the contradiction by enabling selective permeability.
Solution Approach 2:
The hydrophobic membrane acts as an intermediary element between the enclosed internal space and the external environment. It mediates the interaction between the sealed enclosure and external pressure conditions while blocking harmful water ingress, thus allowing pressure equalization without compromising the sealed protection.
3Object-affected harmful factors
If a filter arrangement is added to prevent water ingress, then water protection is improved, but gas flow resistance increases affecting pressure sensing response
Solution Approach 1:
The hydrophobic membrane's microporous structure is specifically engineered to provide low flow resistance for gas molecules while maintaining effective water blockage. The pore size and hydrophobicity are optimized to minimize gas flow resistance while ensuring water prevention, thus resolving the contradiction between water protection and pressure sensing response reliability.
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
The system effectively reduces pressure increases above baseline levels by no more than 5% during impacts, maintaining sensor reliability and preventing water ingress, thus enhancing the accuracy of impact detection and preventing sensor malfunction due to high temperatures or water exposure.
Implementation Method 1
the filter arrangement allows the passage of gas therethrough but prevents or substantially prevents the passage of water through the filter arrangement
Implementation Method 2
a filter arrangement allowing gas passage while preventing water, comprising a gas-permeable and water-resistant material
Data Source
Figure 1~2b
Figure 3a~3d
Figure 4~5
AI summary
A vehicle pressure sensing system, comprising: a pressure sensor; a housing defining an internal space which is in fluid communication with the pressure sensor so that the pressure of gas within the internal space can be sensed by the pressure sensor; a first connection arrangement, allowing connection of the sensor to a substantially enclosed and compressible sensing member, so that variations in pressure in the sensing member are communicated to the internal space; and a venting arrangement, allowing gas communication between the internal space and the surrounding atmosphere, wherein the venting arrangement comprises: a passage comprising or leading to an exit port; a filter arrangement having an inner end and an outer end and being positioned within the passage so that it partially occludes the passage, the filter arrangement having at least one flow path formed therein passing from the inner end to the outer end but preventing or substantially preventing the passage of water through the filter arrangement.