Fuel Level Sensor with Rectified Current and Calibration
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Solution Overview
Problem
Existing liquid level sensors in fuel tanks face accuracy issues due to variations in float placement, resistance values, and changes over time, leading to inconsistent fuel level indications.
Innovation Solution
A liquid level sensor system featuring a float-linked arm with conductive contacts on a variable resistance circuit, including rectifying elements, that adjusts current flow direction to determine resistance values for accurate fuel level measurement, utilizing a microcontroller to store and adjust for variations and calibrate the system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a float-linked variable resistor assembly is used to track liquid level, then the fuel level indication can be obtained, but the accuracy is affected by variations in sensor placement and resistance values over time
Solution Approach 1:
The system performs preliminary calibration by measuring the actual resistance values at known fuel levels (empty, half-full, full) during installation or initial operation. These measured values are stored in memory and used as reference points to compensate for variations in sensor placement and component tolerances, thereby improving measurement accuracy without requiring precise mechanical installation
Solution Approach 2:
The system continuously monitors the resistance values from the variable resistor assembly and compares them against the calibrated reference values stored in memory. Based on this feedback, the microcontroller adjusts the fuel level indication to compensate for drift in resistance values over time, maintaining reliable and consistent readings
2Device complexity
If current flows through the contact in both directions, then the circuit operation is simplified, but the contact experiences increased wear and potential corrosion
Solution Approach 1:
Instead of allowing bidirectional current flow through the contact, the invention introduces a rectifying element that permits current flow in only one direction. This inversion of the conventional bidirectional approach protects the contact from corrosive effects and wear while maintaining circuit functionality through the unidirectional current path
Solution Approach 2:
The rectifying element acts as an intermediary component between the power supply and the variable resistor assembly. It mediates the current flow by allowing passage in the forward direction while blocking reverse current, thereby protecting the contact from damage while still enabling the circuit to operate and provide fuel level indication
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 system provides precise and adaptive fuel level indications by accounting for variations in sensor placement and resistance values, ensuring accurate readings over time and under different conditions.
Implementation Method 1
a float buoyant in the liquid within the tank
Implementation Method 2
a circuit including a rectifying element and) one or more conductive elements, or b) one or more resistive elements
Data Source
AI summary
A liquid level sensor includes a liquid level responsive member that moves in response to changing liquid level, an electrically conductive contact associated with the liquid level responsive member, a circuit including a rectifying element and a) one or more conductive elements, or b) one or more resistive elements or c) one or more conductive elements and one or more resistive elements, wherein the contact is arranged to engage at least one of the elements in a, b, or c, and a power supply. The power supply is adapted to provide a voltage to the circuit causing a current flow in a first direction in the circuit wherein the current flows through the contact and to provide a current flow in a second direction in the circuit wherein the rectifying element prevents current flow through the contact.