Filter Arrangement for SCR Reductant Supply System

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Solution Overview

Problem

The existing reductant supply systems for selective catalytic reduction (SCR) systems face issues with air bubbles entering the reductant reservoir during the purge process, leading to pump pressure drops and priming failures due to aeration, caused by the buoyancy of air in flexible filters and vibration or sloshing in the reservoir.

Innovation Solution

A filter arrangement with a restraining body mounted to the suction tube in the reductant liquid tank, which extends radially outwardly to prevent the filter from floating and directs gas towards the tube inlet, ensuring that air is removed during the priming process, thereby preventing aeration and maintaining pump pressure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a flexible filter is used in the suction tube, then the filter can be easily installed and maintained, but the filter floats upward due to buoyancy of gas, causing air to be drawn back into the reservoir during purge process

Engineering Contradiction:

Improvefilter installationVSAvoidpriming process

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

A restraining body is attached to the filter to counteract the buoyancy force. The restraining body extends radially outwardly from the suction tube and weights the filter assembly down, preventing the flexible filter from floating upward during the purge process when gas accumulates in the filter.

Inventive Principle:

Principle #8Anti-weight (Counterweight)

2Reliability

If the pump draws reductant from the injector back into the reservoir during purge, then damage by freezing is prevented, but air in the filter is also drawn back into the reservoir causing aeration

Engineering Contradiction:

Improvefreezing protectionVSAvoidair bubbles

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The harmful air bubbles are extracted and removed from the system through the suction tube inlet during the purge process. The suction tube inlet is positioned to allow air to be drawn out with the reductant, preventing air accumulation in the reservoir while maintaining the beneficial purge function.

Inventive Principle:

Principle #2Taking out (Extraction)

3Productivity

If the pump draws reductant through the filter during priming, then the reductant supply system is initialized, but air from the filter is drawn into the pump causing priming failure

Engineering Contradiction:

Improvepriming speedVSAvoidpriming success

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

Air is removed from the filter during the purge process before the priming process begins. This preliminary removal of air ensures that when priming starts, the filter contains minimal air that could interfere with the priming operation, thereby increasing priming success rate.

Inventive Principle:

Principle #10Preliminary action

4Ease of operation

If air is released from the filter through the suction tube during operation, then air can escape, but pump pressure drops due to aeration

Engineering Contradiction:

Improveair releaseVSAvoidpump pressure

Core Design Contradiction:

Ease of operationVSStress or pressure

Solution Approach 1:

The air that accumulates in the filter during normal operation is converted from a harmful element into a beneficial flushing mechanism. The air bubbles rise and escape through the suction tube inlet, creating a natural flushing action that prevents aeration in the pump while maintaining stable pressure.

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 filter arrangement effectively removes air from the system during the next operation cycle, ensuring successful priming and preventing pump pressure drops, thus maintaining the integrity of the reductant supply system.

Implementation Method 1

the filter from, under the effects of buoyancy of gas in the filter, floating upwardly

Methodology Applied

Scientific EffectBuoyancy: Archimedes' Principle (Buoyancy)

Implementation Method 2

a filter mounted to a suction tube in a reductant liquid tank

Methodology Applied

Scientific EffectFiltration: Filter (physical)

Data Source

PatentEP4144963B1A filter arrangement for a selective catalytic reduction system

Publication Date: 2024.10.16 PERKINS ENGINES

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AI summary

The present disclosure is directed towards a filter arrangement (11) for a reductant supply system (30) of a selective catalytic reduction system. The reductant supply system (30) comprises a tank (33) and a suction tube (35) mounted at least partially in the tank (33) for receiving reductant liquid (32) from the tank (33). The filter arrangement (11) comprises a restraining body (40), a filter (42) at least partially forming a filter chamber (45), a filter outlet (44) from the filter chamber (45) formed through the restraining body (40) and/or filter (42) and a filter mount (41) mounted to the restraining body (40) and/or filter (42). The restraining body (40) extends radially outwardly from the filter mount (41) and is configured to restrain the filter (42) such that, under the effect of buoyancy in the tank (33) in use, gas in the filter chamber (45) is directed towards the filter outlet (44).