Diaphragm Pressure Sensor Deflection Channel for Thermal Shock Mitigation
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Solution Overview
Problem
Pressure sensors used in internal combustion engines face measurement errors due to temperature-dependent mechanical deformation of the membrane, caused by temperature shock waves, leading to uneven heating and significant temperature gradients among strain gauges.
Innovation Solution
A deflection mechanism is introduced in the connecting channel to guide the gas pressure wave away from directly hitting the membrane, allowing it to cool down and distribute heat evenly across the membrane carrier and membrane, reducing temperature gradients and measurement inaccuracies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a direct connection channel is used between the pressure measuring chamber and the membrane chamber, then the pressure measurement is simple and direct, but the temperature shock wave directly hits the membrane causing measurement errors
Solution Approach 1:
A deflection element is introduced as an intermediary component in the connecting channel. This deflection element redirects the temperature shock wave away from the membrane while still allowing the pressure wave to reach the membrane chamber. The deflection element acts as a mediator that separates the harmful thermal effects from the useful pressure measurement function.
Solution Approach 2:
The connecting channel is segmented into different functional zones by the deflection element. One zone handles the pressure wave transmission to the membrane, while another zone allows the temperature shock wave to be redirected and dissipated separately. This segmentation enables independent optimization of pressure measurement and temperature protection.
2Measurement precision
If the membrane is directly exposed to the pressure wave, then the pressure measurement is direct, but the membrane experiences uneven heating and temperature gradients causing measurement errors
Solution Approach 1:
The deflection element serves as a thermal intermediary that redistributes the temperature shock wave. Instead of the membrane receiving concentrated thermal energy, the deflection element disperses the temperature shock across a larger area and redirects it away from the membrane, reducing temperature gradients.
Solution Approach 2:
The deflection element creates different thermal conditions in different regions. The area behind the deflection element experiences reduced temperature shock, while the deflection element itself absorbs and redistributes the thermal energy. This local differentiation of thermal conditions protects the membrane from uneven heating.
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 deflection mechanism ensures a more homogeneous heating of the membrane and membrane carrier, significantly reducing measurement errors by minimizing temperature differences among strain gauges, thereby improving the accuracy of pressure measurements.
Implementation Method 1
the incoming gas pressure wave is cooled down by the membrane carrier and the sensor carrier
Implementation Method 2
Due to the temperature-dependent linear expansion, the membrane is also mechanically deformed due to the temperature level alone
Implementation Method 3
The membrane has a corresponding measuring device in order to measure its pressure-related deformation
Data Source
Figure 1~2
AI summary
The sensor has a sensor carrier (2) that arranges a membrane carrier (3), which receives a membrane (4). The sensor carrier has a connection channel (11) e.g. boring, which connects a membrane space (7) arranged in front side of the membrane with a pressure measuring space, and a deviation (9) cools a gas pressure wave (14) running from the pressure measuring space through the connection channel in the membrane space. The membrane is covered by the deviation in direction of the connection channel.