Fluid Reservoir Baffle Design for Accurate Liquid Level Sensing

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Solution Overview

Problem

Existing fluid reservoirs for windscreen washing systems in vehicles, such as aircraft, often provide false indications of fluid level due to motion-induced tilting and shocks, leading to unnecessary service events and reduced reliability of the windshield wiping system.

Innovation Solution

A fluid reservoir design featuring a reserve chamber with a baffle portion between the sensing and reserve chambers, along with a sensor to accurately detect liquid levels, is implemented. This design includes a fill axis arrangement and baffles that minimize the impact of tilting and shocks on fluid displacement, ensuring accurate level detection within a predetermined range of aircraft pitch and roll.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional fluid reservoir design is used, then the structure is simple, but the sensor provides false indications due to motion-induced tilting and shocks

Engineering Contradiction:
Improvesensor indication accuracyVSAvoidreservoir structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The reservoir is divided into a sensing chamber and a reserve chamber separated by a baffle portion. The baffle creates a distinct sensing zone that isolates the sensor from fluid motion in the larger reserve chamber, allowing accurate level detection while maintaining overall reservoir functionality

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The baffle portion acts as an intermediary element between the sensing chamber and reserve chamber. It restricts fluid flow between chambers, creating a dampened sensing zone that prevents direct transmission of shocks and tilting effects to the sensor while still allowing fluid level to be accurately sensed

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If the sensing chamber volume is increased to improve detection accuracy, then the sensor can better detect liquid levels, but the overall reservoir capacity is reduced

Engineering Contradiction:
Improveliquid level detection accuracyVSAvoidfluid storage capacity
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The reservoir is segmented into two functional zones: a small sensing chamber optimized for accurate level detection and a large reserve chamber optimized for fluid storage. The baffle separates these zones, allowing each to be optimized for its specific function without compromising the other

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the reservoir are given different qualities: the sensing chamber has properties optimized for measurement (small volume, direct sensor access) while the reserve chamber has properties optimized for storage (large volume). The baffle creates this local differentiation within the overall reservoir structure

Inventive Principle:
Principle #3Local quality

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 allows for accurate detection of liquid levels, reducing the likelihood of wiper dry runs and enhancing the reliability of the windscreen washing system by minimizing erroneous signals caused by tilting and shocks.

Implementation Method 1

a baffle portion located between the sensing chamber portion and the reserve chamber portion

Methodology Applied
Scientific EffectFluid flow restriction:

Implementation Method 2

a sensor positioned on the sensing chamber portion and configured to report presence of a liquid surface within the sensing chamber

Methodology Applied
Scientific EffectLiquid surface detection:

Implementation Method 3

the sensing chamber and the reserve chamber are arranged along a fill axis, wherein the first neck portion and the second neck portion are located on opposite sides of the fill axis

Methodology Applied
Scientific EffectGravitation: Gravitation

Data Source

PatentEP3666608B1Fluid reservoirs for vehicles
Publication Date: 2021.08.18 ROSEMOUNT AEROSPACE INC
  • EP3666608B1 patent drawingFigure 1~2
  • EP3666608B1 patent drawingFigure 3~4
  • EP3666608B1 patent drawingFigure 5~6

AI summary

A fluid reservoir (100) for a vehicle includes a reservoir body with a sensing chamber portion (112), a neck portion (116,118), and a reserve chamber portion (114). The neck portion is connected to the sensing chamber portion and the reserve chamber portion is connected to the sensing chamber portion by the neck portion. The neck portion defines a neck portion volume that is smaller a volume defined by the sensing chamber to limit slosh in the sensing chamber when a reserve volume of fluid is present within the fluid reservoir. Windscreen washing systems (12) and aircraft (10) having fluid reservoirs are also described.