Fuel Tank Breather Filter Baffle Unit Design

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Solution Overview

Problem

Air breather filters in vehicles are prone to soaking due to fluid leakage, leading to increased pressure drops and fuel consumption issues, as existing technologies fail to effectively prevent fluid from entering the filter device through the outlet, causing contamination and unbalanced fuel levels in dual tanks.

Innovation Solution

A filter device with a baffle unit that deflects fluid flows, separating liquid and gaseous fluids, preventing liquid from entering the filter and ensuring gaseous fluids pass through, while using a second filter for liquid fuel and a labyrinth geometry for additional protection against water ingress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the air breather filter is installed in the fuel tank venting system, then the filter can trap small particles and extend engine component lifetime, but the filter paper gets soaked with fuel leakage and pressure drop increases dramatically

Engineering Contradiction:
Improveengine component lifetimeVSAvoidfuel leakage soaking filter
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A baffle unit is introduced as an intermediary element between the filter and the fuel tank interior. The baffle unit has a specific geometry that redirects fuel flow away from the filter, preventing direct contact between fuel and filter paper while allowing air to pass through the filter normally.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The venting system is segmented into distinct functional zones: a filter protection zone created by the baffle unit that separates the filter from direct fuel exposure, and a fuel flow zone that allows normal fuel tank venting. This segmentation enables the filter to perform its particle-trapping function without being contaminated by fuel.

Inventive Principle:
Principle #1Segmentation

2Productivity

If the filter paper is exposed to the fuel tank interior, then the filter can vent air from the tank, but fuel leakage causes the filter to get soaked and pressure drop increases

Engineering Contradiction:
Improvefuel tank venting efficiencyVSAvoidfilter soaking
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The baffle unit serves as a protective intermediary that allows air to pass through to the filter while blocking fuel from reaching the filter. The baffle's geometry creates a flow pattern where air can access the filter for venting purposes, but fuel is redirected along the baffle surface away from the filter media.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If the pressure drop over the filter increases due to fuel soaking, then fuel level unbalance occurs in dual tanks, but the filter cannot be protected from fuel ingress

Engineering Contradiction:
Improvefuel level balanceVSAvoidfluid entering through outlet
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The baffle unit introduces a spatial dimension to the problem solution by creating a three-dimensional flow pattern. Instead of a simple linear path where fuel could directly contact the filter, the baffle creates a redirected flow path in multiple directions, using vertical and horizontal flow components to separate fuel from the filter while maintaining air access.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 prevents filter paper soaking, maintains normal filter operation during fuel leakage, reduces pressure drops, and ensures efficient fuel consumption by separating liquid and gaseous fluids, thereby protecting the filter and maintaining fuel balance in dual tanks.

Implementation Method 1

a baffle unit arranged in the housing for covering the at least one filter in relation to the second port, wherein the baffle unit is arranged to deflect a fluid flow entering the filter device through the second port

Methodology Applied
Scientific EffectFluid flow deflection:

Implementation Method 2

Air breather filters are commonly utilized in vehicles, particularly commercial vehicles such as trucks and buses. They consist of filter paper to be able to catch especially small particles of down to 4 μm and smaller.

Methodology Applied
Scientific EffectFiltration: Filter (physical)

Implementation Method 3

When air is needed for fuel flow, a vacuum within the fuel tank pulls the perimeter of the diaphragm downward, which breaks a seal with the concave bottom to allow air flow which enters the system through an air filter arranged above the diaphragm.

Methodology Applied
Scientific EffectVacuum pressure: Pressure Gradient

Data Source

PatentEP2773523B1Filter device and arrangement for ventilating a tank comprising a filter device
Publication Date: 2017.12.13 VOLVO TRUCK CORP
  • EP2773523B1 patent drawingFigure 1a
  • EP2773523B1 patent drawingFigure 1b
  • EP2773523B1 patent drawingFigure 2a

AI summary

The invention relates to a filter device (10), particularly an air breather filter device for venting a fuel tank, comprising a housing (20) with a first port (12) being provided as an inlet in normal operation of the filter device (10) and a second port (14) being provided as an outlet under normal operation of the filter device (10), the housing (20) enclosing at least one filter (50) and an air passage (40) extending from the first port (12) to the second port (14) passing through the filter (50). Inside the housing (20) a baffle unit (70) is arranged in the housing (20) for covering the at least one first filter (50) in relation to the second port (14), wherein the baffle unit (70) is arranged to deflect a fluid flow entering the filter device (10) through the second port (14).