Integrated Pressure Temperature Sensor Port Geometry
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Solution Overview
Problem
Existing combined temperature and pressure sensors face accuracy and response time issues due to protective packages creating thermal barriers and displacing temperature and pressure sensing elements, which hinder simultaneous and accurate measurement at the same location.
Innovation Solution
A MEMS-based pressure measurement apparatus and thermistor-based temperature measurement apparatus are integrated in a common package with a sensor port geometry that increases the contact area between the fluid media and the temperature sensor, maintaining a centered location and improving response time and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protective package is used to enclose the temperature and pressure sensing elements, then the sensor is protected from environmental forces and corrosive effects, but the protective walls create a thermal barrier that delays the response time of the temperature sensor
Solution Approach 1:
The patent employs a thin-walled protective package structure that minimizes thermal resistance while maintaining mechanical protection. The protective package includes a diaphragm with a thickness of 0.002 to 0.006 inches, which is sufficiently thin to allow rapid thermal conduction from the fluid to the temperature sensing element while still providing protection from environmental forces and corrosive effects.
2Device complexity
If the temperature sensing element and pressure sensing element are displaced some distance from each other to fit within the protective package, then both sensors can be housed in a single package, but the displacement prevents measurement at the same location
Solution Approach 1:
The patent implements a nested configuration where the temperature sensing element is positioned within a cavity formed by the diaphragm, and the pressure sensing element is positioned on the opposite side of the diaphragm. Both sensing elements are displaced no more than 0.020 inches from each other, allowing them to effectively measure at the same location while being housed within a single protective package.
Solution Approach 2:
The patent utilizes the third dimension (depth) by positioning the temperature sensing element within a cavity formed by the diaphragm, rather than placing both sensors on the same plane. This dimensional arrangement minimizes the displacement between sensors while accommodating both within the compact protective package structure.
3Device complexity
If an off-center sensor configuration is used to accommodate both temperature and pressure sensors, then both sensors can be integrated, but the off-center location causes the sensor elements to be deployed in different locations depending on threading tightness
Solution Approach 1:
The patent employs an asymmetric design where the temperature sensing element is positioned within a cavity formed by an asymmetric diaphragm structure. This asymmetric configuration provides natural positioning features that ensure consistent sensor location regardless of threading tightness, eliminating the problems associated with off-center symmetric configurations.
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 faster and more accurate temperature and pressure measurements, enhancing fuel efficiency and emissions control in automotive applications by reducing thermal barriers and maintaining a centered sensor configuration.
Implementation Method 1
temperature sensors include a thermistor to measure a temperature of a fluid
Implementation Method 2
Traditional pressure sensors generally include a diaphragm type pressure sensing element, or a piezo-electric pressure sensing element
Implementation Method 3
The increased contact area provides improved response time and accuracy compared to previously known integrated pressure-temperature sensors
Data Source
AI summary
A combined pressure and temperature sensing device includes a sensor port geometry that provides improved contact between a fluid media being measured and a thermistor cavity of the sensor port. The increased contact area provides improved response time and accuracy compared to previously known integrated pressure-temperature sensors. A temperature sensor element is offset from a pressure sensor element relative to a central axis of the temperature-pressure sensor body/package to facilitate substantially increasing a pressures sensor cavity volume without increasing the overall sensor port diameter. A wire-bondable thermistor support portion facilitates high volume automated production line. The temperature sensing element may be resistance welded to the thermistor support portion in a parallel manufacturing process.