Convex Arc Membrane for Thermal Shock Resistance in Pressure Sensors
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Solution Overview
Problem
Pressure sensors in combustion chambers of internal combustion engines face challenges with thermal shock due to high and rapid temperature fluctuations, leading to measurement errors and reduced service life, as existing membranes optimized for thermal shock either have limited service life or decreased sensitivity.
Innovation Solution
A pressure sensor design featuring a rotationally symmetrical membrane with a convex circular arc segment of constant thickness, where the inner end point of the arc is set back relative to the outer end point, enhancing force distribution and strength, and potentially incorporating a sealing cone or protective sleeve for protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the membrane is made thinner to reduce thermal expansion effects, then thermal shock behavior improves, but strength and service life decrease
Solution Approach 1:
The membrane is designed with a convex arc cross-section instead of being flat or concave. This curved geometry creates an arch structure that naturally distributes mechanical stresses more effectively across the membrane surface, allowing it to withstand higher pressures and thermal stresses without requiring increased thickness. The curvature transforms the membrane from a flat vulnerable surface into a structurally efficient arch that resists deformation while maintaining thin-walled construction for thermal shock resistance.
Solution Approach 2:
The patent applies different geometric characteristics to different regions of the membrane. The cross-section features a convex arc with specific radius and height parameters, while the longitudinal section may include straight portions or different curvature radii. This localized geometric optimization allows the membrane to achieve maximum strength where needed while maintaining overall thin-walled construction for thermal performance.
2Duration of action of stationary object
If the membrane is made thicker to increase service life, then strength improves, but thermal shock behavior deteriorates
Solution Approach 1:
The convex arc cross-section creates an arch structure that provides exceptional strength-to-thickness ratio. This geometric configuration allows the membrane to achieve the structural integrity of a thick membrane while maintaining the thin-walled construction necessary for thermal shock resistance. The arch geometry distributes stresses along the curved surface, preventing stress concentration that would occur in flat or thick membranes.
3Object-affected harmful factors
If the membrane is made thinner to improve thermal shock behavior, then thermal shock resistance improves, but measurement sensitivity decreases
Solution Approach 1:
The convex arc geometry maintains membrane flexibility necessary for pressure transmission to the measuring element while providing structural strength. The curved cross-section allows the thin membrane to deflect appropriately under pressure changes, ensuring that pressure variations are accurately transmitted to the measuring element without the membrane becoming too rigid. This preserves measurement sensitivity while enabling thin-walled construction for thermal shock resistance.
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
This design improves thermal shock behavior and measurement accuracy by reducing stresses within the membrane, thereby extending its service life and maintaining sensitivity.
Implementation Method 1
The cross-section of the ring-shaped membrane segment is designed as a convex arc of a circle on the pressure chamber side with a constant material thickness. The convex arcuate membrane can withstand an external pressure much better than a membrane of other geometry, since the pressure supports the strength of the arch construction.
Implementation Method 2
The membrane transfers the pressure prevailing in the combustion chamber directly or indirectly to the measuring element.
Implementation Method 3
a flexible, ring-shaped membrane segment. The annular diaphragm segment connects the plunger to the peripheral edge portion of the diaphragm.
Data Source
Figure 1~2
Figure 3
AI summary
In a pressure sensor (1) for measuring pressures in pressure chambers (2), in particular in combustion chambers of internal combustion engines, comprising a sensor housing (3) with a longitudinal axis (A) and an interior space (4), a measuring element (5) which is arranged in the interior space (4) of the sensor housing (3), and a rotationally symmetrical diaphragm (6) which has a peripheral edge section (7) by means of which the diaphragm (6) is connected to a pressure chamber-side end of the sensor housing (3) and seals the interior space of the sensor housing (3) on the pressure chamber side; wherein the diaphragm (6) further comprises a central pressure plunger (8) operatively connected to the measuring element (5) and a flexible, annular diaphragm segment (9), wherein the annular diaphragm segment (9) connects the pressure plunger (8) to the peripheral edge section (7) of the diaphragm (6);It is intended that the ring-shaped membrane segment (9) is designed in cross-section as a convex circular arc (10) on the pressure chamber side with constant material thickness.