Fluid Reservoir Bag Filter for DEF Debris Prevention

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Solution Overview

Problem

Existing diesel exhaust fluid (DEF) delivery systems face challenges with debris ingestion and contamination, particularly during refilling, which can lead to clogging and inefficiencies in SCR systems, and existing filtration solutions either impede filling processes or require costly temperature control measures to prevent fluid breakdown.

Innovation Solution

A fluid reservoir with a two-stage filtering system, including a bag filter that encloses the heater and sump location, and an inlet filter with larger porosity to prevent debris and ice accumulation, ensuring reliable DEF supply while maintaining rapid filling capabilities and avoiding thermal issues.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a filter is added at the fill opening or in-line with the DEF supply line, then debris ingestion is prevented, but the filling process is impeded and system complexity increases

Engineering Contradiction:
Improvedebris preventionVSAvoidfilling speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The filter bag is nested within the reservoir body, positioned to hang from the fill opening down into the reservoir. This nested configuration allows the filter to be integrated into the existing reservoir structure without adding external components that would impede filling operations, while still effectively capturing debris during both filling and operation.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The filter bag acts as an intermediary element between the fill opening and the DEF storage area. It intercepts debris before it can reach the pump or injector, while its positioning and design allow DEF fluid to pass through freely during filling operations, thus mediating between debris prevention and filling efficiency requirements.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If in-line filters are used in the DEF supply line, then debris is filtered, but the aqueous components are susceptible to thermal effects and freezing at low temperatures

Engineering Contradiction:
Improvedebris filtrationVSAvoidfreezing risk
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The filtration function is extracted from the traditional in-line supply line location and relocated to the reservoir interior where the filter bag hangs from the fill opening. This extraction removes the filter from the vulnerable supply line environment where thermal effects and freezing risks are present, while maintaining effective debris filtration at the source.

Inventive Principle:
Principle #2Taking out (Extraction)

3Temperature

If heaters and temperature control devices are added to DEF supply systems, then thermal effects and freezing are prevented, but system cost and complexity increase

Engineering Contradiction:
Improvethermal protectionVSAvoidsystem complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The invention accepts that thermal effects and freezing risks exist in the supply line, but converts this potential harm into a benefit by positioning the filter bag within the reservoir where it is naturally protected from extreme temperatures. The reservoir environment itself becomes the protective element, eliminating the need for active heating or temperature control systems.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 two-stage filtering system effectively prevents debris and ice ingestion, ensuring continuous and efficient DEF delivery to the SCR system, reducing clogging risks and eliminating the need for costly temperature control measures, thus enhancing operational efficiency and reliability.

Implementation Method 1

A bag filter is connected to the header. The bag filter completely encloses the heater and the sump location of the fluid draw conduit within the reservoir volume such that, when fluid is drawn from the reservoir volume through the sump location, the fluid is first filtered by the bag filter.

Methodology Applied
Scientific EffectFiltration: Filter (physical)

Data Source

PatentEP3094838B1Fluid reservoirs with filter bag
Publication Date: 2021.06.02 CATERPILLAR INC
  • EP3094838B1 patent drawingFigure 1
  • EP3094838B1 patent drawingFigure 2~3
  • EP3094838B1 patent drawingFigure 4

AI summary

A fluid reservoir (128) includes a reservoir (128) body (274) forming a reservoir volume (204) and a header opening (222). A header (202) seals the header opening (222) and includes at least a heater (212) disposed within the reservoir volume (204) and a fluid draw conduit (106). A bag filter (240) is connected to the header (202) such that it completely encloses the heater (212) and the fluid draw conduit (106) such that, when fluid is drawn from the reservoir volume (204) through the sump (218) location, the fluid is filtered by the bag filter (240)