Float Fluid Level Sensing Using Magnetic Field Angle Detection
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Solution Overview
Problem
Existing sensors and techniques for determining fluid levels, such as Diesel Exhaust Fluid (DEF) in vehicle tanks, are not always satisfactory in terms of accuracy and reliability.
Innovation Solution
A fluid sensor system utilizing a float constrained by a guide, a permanent magnet, and a magnetic angle sensor to measure the angle of the magnetic field generated by the magnet, allowing for precise fluid level detection through the variation of the magnetic field angle as the float moves along a vertical axis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional sensors and techniques are used for fluid level sensing, then the system is simple in structure, but the measurement precision and reliability are not satisfactory
Solution Approach 1:
The patent replaces conventional mechanical contact-based fluid level sensors with a magnetic field-based non-contact sensing system. A permanent magnet is attached to the float, and a magnetic angle sensor measures the magnetic field angle to determine float position and fluid level, eliminating the need for direct mechanical contact between the sensor and float while achieving high measurement precision
Solution Approach 2:
The patent introduces a permanent magnet as an intermediary element that couples the mechanical float movement to the magnetic angle sensor. The magnet translates the float's linear motion into a varying magnetic field angle that the sensor can measure, providing accurate fluid level detection without direct mechanical contact between the sensor and float
2Measurement precision
If a magnetic angle sensor with a permanent magnet is used, then the measurement precision is improved, but the device complexity increases
Solution Approach 1:
The magnetic angle sensor serves multiple functions: it measures the magnetic field angle to determine float position, inherently compensates for vertical accelerations through its measurement principle, and provides accurate fluid level detection across the entire measurement range. This multi-functionality reduces the need for additional separate components
3Measurement precision
If the float moves along the vertical axis, then the fluid level measurement is achieved, but the measurement is affected by vertical accelerations
Solution Approach 1:
The patent replaces direct mechanical position measurement with magnetic field angle measurement. The magnetic angle sensor measures the angle of the magnetic field generated by the permanent magnet on the float, which varies as the float moves vertically. This non-contact magnetic measurement method is insensitive to vertical accelerations, eliminating the interference problem
4Reliability
If a non-contact measurement method is used, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The permanent magnet acts as an intermediary that enables non-contact measurement. It carries the float's position information through the magnetic field to the magnetic angle sensor without requiring direct mechanical contact, thereby improving reliability by eliminating wear and friction issues while maintaining a relatively simple overall system structure
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
Provides a linear, non-contact method for fluid level measurement that is independent of horizontal position shifts and resistant to vertical accelerations, offering accurate and reliable fluid level detection.
Implementation Method 1
a magnetic angle sensor configured to measure an angle of a magnetic field generated by the permanent magnet and positioned such that movement of the float along the vertical axis varies the angle of the magnetic field generated by the permanent magnet through the magnetic angle sensor
Implementation Method 2
The position of the float is influenced by a volume of the float submerged below a surface of the fluid
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A fluid sensor including a guide, a float, a permanent magnet, and a magnetic angle sensor. In one example, the float is constrained at least in part by the guide to move along a vertical axis. The permanent magnet is mechanically coupled to the float. The magnetic angle sensor is configured to measure an angle of a magnetic field generated by the permanent magnet and is positioned such that movement of the float along the vertical axis varies the angle of the magnetic field generated by the permanent magnet through the magnetic angle sensor.