Compressible Volume Reduction Member for Freezing Reductant Damage
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Solution Overview
Problem
Non-purge SCR systems face damage from reductant expansion due to freezing in the RDU injector, as the reductant remains in the injector during cold conditions, leading to potential system failure.
Innovation Solution
A fluid injector with a volume reduction member made from resilient, compressible materials such as rubber or closed-cell foam, which compresses to accommodate expanding reductant, reducing the volume of the reductant fluid path and minimizing damage from freezing forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the RDU injector remains filled with reductant in non-purge SCR systems, then the system maintains readiness for immediate operation, but the injector becomes susceptible to damage from reductant expansion during freezing conditions
Solution Approach 1:
The patent introduces a compressible material (such as a spring element or foam) positioned in the reductant flow path that acts as a cushioning element before freezing occurs. This material is pre-installed to compress and absorb the expansion forces when reductant freezes, preventing damage to the injector body and internal components.
Solution Approach 2:
The patent employs an intermediary compressible material placed between the reductant and the injector structure. This intermediary element absorbs the mechanical stress of freezing reductant expansion, mediating the interaction between the harmful expanding ice and the vulnerable injector components, thereby protecting the system while maintaining operational readiness.
2Object-affected harmful factors
If the volume of reductant in the injector is reduced to prevent freezing damage, then the susceptibility to expansion damage decreases, but the amount of reductant available for immediate injection is also reduced
Solution Approach 1:
By installing the compressible material in advance, the system can maintain a larger volume of reductant in the injector without increasing freezing damage risk. The cushioning element provides a safety buffer that allows maximum reductant storage while protecting against expansion forces, resolving the trade-off between quantity and safety.
3Object-affected harmful factors
If purge systems are used to empty the reductant from the RDU when the vehicle is turned off, then freezing damage is prevented, but system complexity and operational convenience are reduced
Solution Approach 1:
The patent extracts the protective function from the complex purge system architecture and integrates it directly into the injector body as a built-in compressible element. This eliminates the need for separate purge valves, control logic, and associated components, significantly reducing system complexity while maintaining freezing protection.
Solution Approach 2:
The compressible material within the injector provides automatic, passive protection against freezing damage without requiring active control systems, sensors, or additional components. The system protects itself through the inherent mechanical properties of the compressible element, eliminating the need for complex purge management systems.
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 susceptibility of the injector to damage from reductant expansion by minimizing the volume of reductant that can freeze, thereby enhancing the robustness of the RDU injector in cold conditions.
Implementation Method 1
The resilient, compressible material includes one of a rubber composition and closed cell foam... freezing or frozen reductant disposed in the calibration filter tube expands through the holes and at least partially compresses the volume reduction member
Implementation Method 2
AUS-32, or AdBlue, has a freezing point of -11 C, and system freezing is expected to occur in cold climates. Since these fluids are aqueous, volume expansion happens after the transition to the solid state upon freezing.
Data Source
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AI summary
A fluid injector includes a calibration filter tube including a bore defined in an axial direction through the calibration filter tube, the bore defining at least a portion of a fluid path through the fluid injector, the calibration filter tube including a plurality of holes which extend from the bore to an outer surface of the calibration filter tube. A volume reduction member has a bore though which the calibration filter tube extends, the volume reduction member occupying a space between the outer surface of the calibration filter tube and an inner surface of the tube member, the volume reduction member being constructed from resilient, compressible material. Freezing or frozen fluid disposed in the calibration filter tube expands through the holes and at least partially compresses the volume reduction member, so as to reduce fluid expansion forces damaging other components of the fluid injector.