Fuel Sensor with Shielding and Dual-Mode Detection
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Solution Overview
Problem
Existing sensors for measuring electrochemical properties of fluids in electromagnetically polluted environments, such as those in vehicles, face challenges like interference, measurement errors due to electromagnetic interference, and dirt build-up, especially when designed for dynamic sensing or large tanks, leading to reduced accuracy and reliability.
Innovation Solution
A sensor design with axial inner electrodes and a cylindrical or frustoconical outer electrode, housed in a fuel rail, utilizing a shielding element to reduce noise and prevent dirt build-up, with adjustable electrode spacing for optimal measurement sensitivity and resistance/capacitance detection, and integrated with a temperature probe for compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the radial distance between electrodes is increased to facilitate fluid outflow and avoid dirt build-up, then the flow characteristics improve, but the sensor properties change from capacitive to resistive detection, reducing dynamic sensing capability
Solution Approach 1:
The patent implements a dual-mode detection system that can dynamically switch between capacitive and resistive detection modes. The sensor includes both a measuring capacitor (Cm) with adjustable electrode spacing for capacitive detection and a measuring resistor (Rm) for resistive detection, allowing the system to adapt to different fluid conditions and maintain optimal performance across varying operational requirements.
2Productivity
If the sensor is installed in proximity to interference sources such as combustion engines, then the sensor can monitor fuel properties in real-time, but electromagnetic interference affects the measurement process
Solution Approach 1:
The patent employs a shielding element (Erdschirm) that is electrically connected to the housing and positioned between the electrodes and the external environment. This shielding structure converts the harmful electromagnetic interference into a controllable factor by providing a reference potential and creating a controlled electric field environment, thereby protecting the sensitive measurements while maintaining real-time monitoring capability.
3Measurement precision
If laboratory equipment is used to measure electrochemical properties of fluids, then measurement accuracy is improved, but the equipment becomes complex and delicate, making practical use in vehicles hardly practicable
Solution Approach 1:
The patent integrates multiple detection functions into a single compact sensor unit. The sensor simultaneously provides capacitive detection (for dielectric constant measurement), resistive detection (for conductivity measurement), and temperature measurement, all within one device that can be directly installed in the fuel system. This multi-functional integration eliminates the need for separate laboratory equipment while maintaining measurement accuracy and enabling practical vehicle application.
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 provides accurate and reliable detection of fluid properties with reduced electromagnetic interference and improved sensitivity, capable of dynamic sensing and resistant to dirt build-up, ensuring precise measurements in electromagnetically challenging environments.
Implementation Method 1
a measuring capacitor (Cm) having an inner electrode (12, 13) and an outer electrode (14), said inner electrodes (12, 13) being arranged coaxially to said outer electrode (14), said inner electrodes (12, 13) and said outer electrode (14) being spaced apart from each other by a given radial distance
Implementation Method 2
a measuring capacitor (Cm) having an inner electrode (12, 13) and an outer electrode (14)... for detecting changes in the dielectric and/or in the electrical conductivity of the liquid fuel
Implementation Method 3
a measuring resistor (Rm) having a first inner electrode (12, 13) and a second inner electrode (12, 13), said first inner electrode (12, 13) being arranged coaxially to said second inner electrode (12, 13), said first inner electrode (12, 13) and said second inner electrode (12, 13) being spaced apart from each other by a given axial distance... for detecting changes in the dielectric and/or in the electrical conductivity of the liquid fuel
Implementation Method 4
a shielding element (24), in particular a housing, arranged to shield the inner electrodes (12, 13) and the outer electrode (14) from external interference
Data Source
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AI summary
The invention relates to a sensor for detecting the properties of the fuel of an internal combustion engine. The sensor comprises at least one pair of internal electrodes (12, 13) extending in an axial direction relative lo a further or third external electrode (14) which surrounds them. The invention also relates lo a fuel rail (2) to which the sensor may be mounted, and a method for detecting the properties of the fluid.