Cavitation Anti-Resonance End Piece for Engine Pressure Sensor
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Solution Overview
Problem
Pressure sensors integrated into the combustion chamber of internal combustion engines face issues with soot deposits and parasitic acoustic waves, which lead to measurement noise and reduced sensitivity due to cavitation phenomena and thermal disturbances.
Innovation Solution
A pressure sensor design featuring an elongate frustoconical end piece that breaks the direct communication between the tubular cavity and the pressure-measuring means, creating a Venturi effect and forming a gas pocket for thermal isolation, preventing soot deposition and reducing acoustic wave interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a tubular cavity is used to give access to the combustion chamber, then the pressure sensor can measure combustion pressure, but parasitic acoustic waves are generated causing measurement noise
Solution Approach 1:
The end piece extracts the harmful acoustic wave propagation path from the system by blocking the tubular cavity opening with a hemispherical convexity, preventing wave reflection and cavitation while maintaining pressure measurement capability through the membrane
Solution Approach 2:
The end piece acts as an intermediary element between the tubular cavity and the pressure-measuring means, modifying the acoustic field by absorbing or dissipating wave energy at the cavity opening while allowing pressure transmission to the membrane
2Measurement precision
If the sensor is positioned facing the combustion chamber, then pressure measurement is enabled, but soot deposits on the sensor surface causing measurement distortion
Solution Approach 1:
The end piece extracts the sensor from direct exposure to soot-laden combustion gases by positioning the hemispherical convexity at the cavity opening, creating a protective barrier that prevents soot deposition on the membrane while maintaining pressure measurement capability
Solution Approach 2:
The end piece serves as a protective intermediary between the combustion chamber environment and the pressure-measuring means, filtering out soot particles while allowing pressure waves to reach the membrane sensor
3Measurement precision
If the sensor is exposed to combustion chamber thermal environment, then combustion pressure can be measured, but thermal shocks cause sensor deformations and reduce service life
Solution Approach 1:
The end piece extracts the sensor from the harsh thermal environment of the combustion chamber by positioning the hemispherical convexity at the cavity opening, creating a thermal barrier that reduces thermal shock exposure while maintaining pressure measurement capability through the membrane
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 ensures reliable pressure readings by minimizing soot deposits and acoustic wave disturbances, improving measurement accuracy and extending the sensor's service life by reducing thermal sensitivity and coking.
Implementation Method 1
creating a Venturi effect and forming a gas pocket for thermal isolation
Implementation Method 2
preventing soot deposition
Implementation Method 3
cavitation phenomena
Implementation Method 4
oscillatory harmonic acoustic waves. Such waves are due to the propagation of the pressure waves in the tube
Data Source
AI summary
A pressure sensor for an internal combustion engine, which includes: a body containing a pressure-measuring membrane and a device for attaching to the cylinder head of the engine; and an end piece which extends substantially in an axial extension of the body, and includes a long part, and a substantially hemispherical convexity positioned on the end part of the long part.