Sensor Cover Apertures for Diesel Exhaust Fluid Bubble Management
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Sensors in diesel exhaust fluid tanks face interference from air or gaseous bubbles formed due to fluid splashing or sloshing, leading to inaccurate measurements of fluid concentration and quality.
Innovation Solution
A sensor assembly with a cover assembly that is impermeable to gases except for specific apertures or slots, allowing gas bubbles to escape while maintaining the integrity of the sensing volume, and a baffle to prevent bubbles from entering the sensing area, ensuring accurate fluid concentration and quality detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the sensing volume is enclosed to protect the sensor, then measurement precision is improved, but gas bubbles accumulate inside the sensing volume causing measurement distortion
Solution Approach 1:
The cover assembly incorporates a porous structure with controlled permeability that allows gas bubbles to pass through while blocking liquid fluid. The porous material enables selective transmission based on phase differences between gas and liquid, resolving the contradiction by allowing gas escape while maintaining sensor protection and measurement accuracy.
Solution Approach 2:
The cover assembly acts as an intermediary component between the sensor and the fluid environment. It mediates the interaction by selectively permitting gas passage while preventing liquid access to the sensor, thus protecting the sensor from harmful gas bubble interference while maintaining measurement precision.
2Quantity of substance
If the tank fluid level is low, then fluid consumption is reduced, but air bubbles form due to splashing causing sensor interference
Solution Approach 1:
The porous cover assembly converts the harmful effect of air bubbles entering the sensing volume into a beneficial outcome by allowing these bubbles to escape through the porous structure. The same feature that would normally cause measurement interference (gas permeability) is used to eliminate the interference source, enabling accurate measurement even at low fluid levels.
3Object-affected harmful factors
If the cover assembly is made impermeable to gas, then gas bubble interference is prevented, but gas bubbles cannot escape from the sensing volume
Solution Approach 1:
The cover assembly exhibits local quality differences in its permeability characteristics. Different regions or aspects of the cover have different permeability properties, allowing it to block liquid while permitting gas passage. This localized differentiation in material properties resolves the contradiction by providing selective permeability tailored to specific functional requirements.
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 solution effectively reduces the impact of air bubbles on sensor accuracy, allowing for reliable detection of fluid concentration and quality even when the fluid level is low, thereby enhancing the precision of fluid management in diesel exhaust systems.
Implementation Method 1
a transmitter configured to transmit a signal into a sensing volume and a receiver configured to receive the signal after the signal passes through a portion of the sensing volume; wherein the signal is sonic
Implementation Method 2
a cover assembly at least partially enclosing the sensing volume and being substantially impermeable to a gas portion of the fluid, the cover assembly including apertures defined therein which are permeable to the gas portion of the fluid
Data Source
AI summary
A sensor assembly is provided for detecting a concentration of a fluid. The sensor assembly includes a sensing unit and a cover assembly. The sensing unit includes a transmitter configured to transmit a signal into a sensing volume and a receiver configured to receive the signal after the signal passes through a portion of the sensing volume. The cover assembly at least partially encloses the sensing volume and is substantially impermeable to a gas portion of the fluid. The cover assembly includes apertures defined therein which are permeable to the gas portion of the fluid. A first plurality of apertures are defined along a top surface of the cover assembly.