Epoxy Resin PCB Differential Pressure Sensor for Exhaust Gas
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Solution Overview
Problem
Prior differential pressure sensors for exhaust gas systems are expensive due to the use of ceramic printed circuits and often inadequately protect electrical connections from aggressive exhaust gases, leading to partial exposure.
Innovation Solution
A differential pressure sensor utilizing an epoxy resin printed circuit board with a protective housing filled with epoxy resin to create isolated pressure paths and encapsulate electrical connections, eliminating the need for a protective wall and reducing manufacturing complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a ceramic printed circuit board is used, then resistance to aggressive exhaust gas environment is improved, but manufacturing cost increases
Solution Approach 1:
The patent changes the material parameter of the printed circuit board from ceramic to epoxy resin, which is inherently resistant to exhaust gas corrosion. This eliminates the need for additional protective coatings while maintaining reliability and reducing manufacturing complexity
Solution Approach 2:
The patent uses an epoxy resin printed circuit board that combines the substrate and protective function in a single composite material, eliminating the need for separate ceramic layers or protective coatings, thus reducing cost and simplifying manufacturing
2Reliability
If a protective wall is added to shield electrical connections, then protection from exhaust gases is improved, but device complexity increases
Solution Approach 1:
The patent merges the protective function with the printed circuit board itself by using exhaust gas-resistant epoxy resin material. The PCB serves both as the electrical connection substrate and as the protective barrier, eliminating the need for a separate protective wall structure
Solution Approach 2:
The epoxy resin printed circuit board performs multiple functions simultaneously: it provides electrical connections, structural support, and protection against aggressive exhaust gas environment. This multi-functionality eliminates the need for additional protective components
3Reliability
If gel is applied to protect pressure sensitive element, then resistance to exhaust gas fouling is improved, but manufacturing steps increase
Solution Approach 1:
The patent applies the protective effect at the material selection stage by choosing epoxy resin that is inherently resistant to exhaust gas corrosion. This preliminary action eliminates the need for subsequent gel application steps, simplifying the manufacturing process
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 solution provides a cost-effective and more robust differential pressure sensor that effectively insulates electrical components from exhaust gases, enhancing resistance to the harsh environment while simplifying the manufacturing process.
Implementation Method 1
a solid material partially filling the cavity of the protective housing and coating the printed circuit so as to insulate its external surface from exhaust gases
Implementation Method 2
to form two pressure paths isolated from each other by the solid material, including a first pressure path connecting the first pressure inlet to the lower surface of the pressure-sensitive element and a second pressure path connecting the second pressure inlet to the upper surface of the pressure-sensitive element
Implementation Method 3
a pressure sensitive element... mounted on the printed circuit board... electrically connected to the pressure-sensitive element
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The present invention relates to a differential pressure sensor (1) for measuring the pressure in an exhaust gas pipe of a heat engine, and to the manufacturing method thereof. The differential pressure sensor (1) for measuring the pressure in an exhaust gas pipe of a heat engine includes a pressure-sensitive element (2), a printed circuit (3) including an opening (4) that is closed by the pressure-sensitive element (2), and electronic components that are electrically connected to the pressure-sensitive element (2) by means of electrical connections (5), and a protective housing (6) including a cavity (7) in which the printed circuit (3) and the pressure-sensitive element (2) are housed. Said protective housing (6) includes a first pressure inlet (8) and a second pressure inlet (9). According to the invention, the printed circuit (3) is an epoxy resin printed circuit, and the pressure sensor (1) includes a solid material (10) that partially fills the cavity (7) of the protective housing (6) and coats the printed circuit (3) so as to insulate the outer surface thereof that comprises the exhaust gas copper tracks (11 and 32) and so as to form two pressure paths (12a, 12b) that are insulated from one another by the solid material (10), a first pressure path (12a) of said paths connecting the first pressure inlet (8) to the bottom surface (13) of the pressure-sensitive element (2) and a second pressure path (12b) of said paths connecting the second pressure inlet (9) to the top surface (14) of the pressure-sensitive element (2).