Supply Modulation Driver for Two-Wire Fluid Level Sensor Compatibility
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Solution Overview
Problem
Existing fluid level sensor products with three-wire connections are not compatible with two-wire float switches, which are unreliable due to temperature-dependent magnetic forces and require a signal line not available in two-wire systems, limiting their use in applications like automotive washer fluid containers.
Innovation Solution
A three-wire fluid level sensor assembly with a supply modulation driver that fluctuates the output signal between low and high levels, allowing it to interface with a two-wire ECU by creating a voltage oscillation, effectively mimicking a two-wire sensor and eliminating the need for magnets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a three-wire fluid level sensor is used, then measurement precision and reliability are improved, but device complexity and wiring requirements increase
Solution Approach 1:
The patent combines the third wire (signal output) function into the existing two-wire configuration by using the signal line to carry both supply voltage and output signal. The ECU detects fluid level changes by monitoring voltage fluctuations on this combined line, eliminating the need for a separate signal wire while maintaining three-wire sensor functionality.
Solution Approach 2:
The existing two-wire connection is made multi-functional by using it to carry both power supply and signal output functions. The ECU configures the input pin as an analog input that can detect voltage changes caused by the sensor's output, allowing the same physical connection to serve multiple purposes.
2Device complexity
If a two-wire float switch with magnets is used, then device complexity is reduced, but reliability deteriorates due to temperature-dependent magnetic force
Solution Approach 1:
The patent replaces the mechanical magnetic float switch system with an electronic fluid level sensor that uses electrical fields instead of magnetic fields. This substitution eliminates the temperature-dependent magnetic force issues while maintaining the simplicity of the two-wire connection through signal modulation on the available wires.
3Adaptability or versatility
If a three-wire sensor is adapted to two-wire system, then adaptability is improved, but device complexity increases due to supply modulation driver
Solution Approach 1:
The patent merges the signal output function into the power supply line by using voltage fluctuations on the two-wire connection to convey fluid level information. The supply modulation driver modulates the voltage on the shared line, allowing the ECU to detect fluid level changes without requiring a separate signal wire.
Solution Approach 2:
The supply modulation driver acts as an intermediary that translates the three-wire sensor's output signal into voltage fluctuations that can be detected by the two-wire ECU system. This intermediary component enables communication between incompatible interfaces by converting signal types.
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
Enables the use of three-wire fluid level sensors in two-wire float switch applications, improving reliability by avoiding temperature-dependent magnetic issues and providing accurate fluid level detection without loading the signal line, thus enhancing compatibility and performance.
Implementation Method 1
a supply modulation driver circuit 130. The supply modulation driver circuit (130) has a first input terminal 131 and a second input terminal 132. The supply modulation driver circuit (130) has an output terminal 133 electrically connected to the signal line (113). The supply modulation driver circuit (130) is configured to create a voltage oscillation
Implementation Method 2
a fluid level sensor 110 including first, second, and third wires (111, 112, 113). The third wire (113) carries an output signal configured to fluctuate between a low output signal level and a high output signal level
Data Source
AI summary
An active three-wire fluid level sensor employed in an application designed for a two-wire switch is disclosed. A fluid level sensor assembly includes a fluid level sensor including first, second, and third wires. The third wire carries an output signal configured to fluctuate between a low output signal level and a high output signal level. The fluid level sensor assembly also includes a supply modulation driver electrically connected to the third wire. The fluid level sensor, via the first, second, and third wires, is configured to serve as an input to a two-wire input electronic control unit (ECU). A method of operating a two-wire circuit function by supply modulation is also disclosed.