Flat Surface Temperature Sensor for Fluid Circuits
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Solution Overview
Problem
Existing temperature sensors for fluid circuits in motor vehicles are prone to disturbing fluid flow and are complex and expensive to manufacture, with reliability issues due to sensitive elements being housed in parts that can foul and connected by fragile means.
Innovation Solution
A temperature sensor with a body made of plastic or composite material, featuring a flat surface with an elongated thermosensitive track connected to electrical conductors embedded within the body, minimizing flow disturbance and optimizing signal transmission time, and having a simple, economical design with low fouling risk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a cage with cavity is used to position the sensitive element, then the sensitive element can contact the fluid flow, but the cage causes disturbance in the flowing of the flow
Solution Approach 1:
The patent removes the cage and cavity structure from the sensor design. Instead of housing the sensitive element in a three-dimensional cavity that disrupts flow, the sensitive element is applied directly as a thin track on the flat outer surface of the sensor body, eliminating the flow-disturbing cage structure while maintaining measurement capability.
Solution Approach 2:
The sensitive element is transitioned from being positioned within a three-dimensional cavity to being applied on a two-dimensional flat surface. This dimensional change allows the sensitive element to contact the fluid flow without creating the flow disturbances associated with three-dimensional cage structures.
2Reliability
If multiple pieces of different materials are used to construct the sensor, then the sensor can be functional, but the sensor becomes complex and expensive to manufacture
Solution Approach 1:
The patent combines multiple functional components into a single integrated sensor body made of one material (polyamide 6). The sensitive element, electrical conductors, and structural housing are merged into a unified component that can be manufactured in a single injection molding process, eliminating the need to assemble multiple pieces of different materials.
Solution Approach 2:
The sensor body performs multiple functions simultaneously: it provides structural support, houses the sensitive element, contains electrical conductors, and facilitates fluid flow. This multi-functionality is achieved through a single-component design that integrates all these features into one polyamide 6 part.
3Strength
If the sensitive element is housed in a part that can foul, then the sensitive element is protected, but the reliability of the sensor deteriorates due to fouling and fragile connections
Solution Approach 1:
Instead of housing the sensitive element within a protective cavity that can accumulate fouling, the patent inverts the approach by applying the sensitive element on the outer flat surface of the sensor body. This positioning allows the fluid flow to naturally sweep across and clean the sensitive element, preventing fouling while maintaining protection through the robust polyamide 6 material.
4Ease of manufacture
If fragile means such as soldering are used to connect the sensitive element to terminals, then the sensor can be assembled, but the reliability is not optimal due to fragile connections
Solution Approach 1:
The patent replaces fragile mechanical connections (soldering) with robust integral connections. The sensitive element, electrical conductors, and terminals are all embedded within and mechanically integrated into the polyamide 6 sensor body through injection molding, creating strong, reliable connections that are resistant to vibration and thermal cycling.
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 measures fluid temperature with minimal flow disruption, rapid signal transmission, and enhanced reliability, being easy and cost-effective to manufacture while reducing the risk of fouling.
Implementation Method 1
a track (41) forming said thermosensitive element, this track having a generally elongated shape and comprising opposite ends connected respectively to said terminals by electrical conductors (42) embedded in said body
Data Source
AI summary
The invention relates to a temperature sensor (10) for a fluid pipe, in particular for a motor vehicle, this sensor (10) comprising a first part (20) comprising a flat surface (22) configured to be in contact with a fluid and on which is located a track (41) forming a thermosensitive element (40), this track (41) having a generally elongated shape and comprising opposite ends (41A, 41B) connected respectively to terminals (43) of the sensor (10) by electrical conductors (42) embedded in said body (15).The invention also relates to a fluid pipe comprising such a sensor (10), a motor vehicle comprising such a sensor (10) or such a pipe and a method for manufacturing such a sensor (10).