Membrane Pressure Sensor Elastic Measuring Spring for Combustion Engine
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Solution Overview
Problem
High-temperature and high-pressure diaphragm pressure sensors in internal combustion engines are prone to failure due to inability to absorb and cushion pressure peaks, leading to rapid destruction from sudden pressure surges.
Innovation Solution
A diaphragm pressure sensor design featuring an elastically resilient measuring spring with a central bore and radial play, which absorbs pressure shocks through elastic deformation, reducing the impact on the measuring surface and preventing destruction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a non-elastic pressure plunger is used to transmit pressure to the piezoelectric measuring element, then the pressure transmission is direct and simple, but the pressure peaks cannot be absorbed and cushioned, leading to rapid destruction of the membrane surface
Solution Approach 1:
The patent applies beforehand cushioning by introducing an elastic measuring spring that can absorb and cushion pressure peaks before they reach the membrane surface. The measuring spring is designed with elastic properties to deform under pressure peaks, thereby protecting the membrane from direct impact of pressure surges and extending its service life.
Solution Approach 2:
The patent changes the mechanical parameter of the pressure transmission element from non-elastic (rigid plunger) to elastic (measuring spring). This parameter change allows the system to absorb pressure peaks through elastic deformation, transforming the rigid pressure transmission into a compliant one that can withstand pressure surges without destroying the membrane surface.
2Ease of manufacture
If a loosely displaceable structure with plugged components is used, then assembly is simple, but components displace during operation causing warping and unfavorable bending frequency
Solution Approach 1:
The patent applies segmentation by dividing the pressure transmission system into distinct functional segments: the diaphragm disk, the measuring spring, and the mounting sleeve. Each segment has a specific function and is connected in a way that maintains positional stability during operation while allowing for thermal expansion and contraction without causing warping or displacement.
Solution Approach 2:
The patent introduces an intermediary mounting sleeve that mediates between the measuring spring and the sensor housing. This intermediary component provides a stable mounting structure that prevents displacement of the measuring spring during operation, while also allowing for thermal compensation, thereby maintaining component position stability without compromising assembly simplicity.
3Reliability
If a very long measuring spring is used to clamp piezoelectric measuring elements, then the spring can absorb pressure peaks, but the long construction results in unfavorable bending frequency preventing accurate measurement
Solution Approach 1:
The patent optimizes the geometric parameters of the measuring spring, specifically the ratio of length to diameter and the wall thickness. By changing these parameters, the spring achieves the right balance between pressure peak absorption capability and bending frequency characteristics. The spring is designed to be long enough to provide adequate cushioning but with adjusted dimensions to maintain favorable bending frequency for accurate measurement.
Solution Approach 2:
The patent employs composite material construction for the measuring spring, combining materials with appropriate elastic moduli and damping characteristics. This allows the spring to achieve both pressure peak absorption and optimal bending frequency properties that would be difficult to obtain with a single material, thereby resolving the contradiction between reliability and measurement precision.
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 sensor effectively dampens pressure peaks, extending its service life and preventing destruction from extreme pressure shocks, while maintaining accurate measurements and resisting temperature fluctuations.
Implementation Method 1
A diaphragm pressure sensor design featuring an elastically resilient measuring spring with a central bore and radial play, which absorbs pressure shocks through elastic deformation
Data Source
Figure 1A~1C
Figure 2~5
Figure 6~10
AI summary
Membrane pressure sensor for detecting the combustion chamber pressure in internal combustion engines, in particular diesel engines and gas engines, wherein a membrane disk (12) is provided on the front of a sensor housing (1, 1', 1"), sealed to the sensor housing (1, 1', 1") and exposed to the combustion chamber atmosphere, the deflection of which can be transmitted to a sensor via one or more transmission elements, wherein, for transmitting the deflection of the membrane disk (12) to a measuring surface (18) of a sensor (19, 20), a measuring spring (10, 10', 10") with an approximately hat-shaped or sleeve-shaped profile is connected to the membrane disk (12) at its lower axial end, and is connected at its opposite axial end to a mounting sleeve (7) forming a radial cavity (42), and wherein the assembly of measuring spring (10, 10', 10") and mounting sleeve (7) has a radial clearance (45) to the inner circumference of the sensor housing (1, 1', 1").