Delivery Unit Deformable Sleeve Freezing Protection
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Solution Overview
Problem
Delivery units for liquid additives in motor vehicles, such as urea-water solutions, face issues with freezing at low temperatures, leading to volume expansion that can damage the unit, and require cost-effective production with high dosing accuracy and long service life.
Innovation Solution
A delivery unit design featuring a block with ducts connecting active components to a cylindrical collecting chamber, incorporating a deformable sleeve-shaped element that accommodates volume expansion during freezing, and uses a plastic block and elastic sleeve-shaped element for pressure compensation and cost-efficient production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a delivery unit stores liquid additive (urea-water solution) for use in motor vehicles, then it enables dosing of the additive to exhaust-gas treatment devices, but the liquid additive freezes at low temperatures causing volume expansion that can damage the delivery unit
Solution Approach 1:
The patent employs a flexible membrane that can deform elastically to accommodate volume expansion of the liquid additive when it freezes. This membrane acts as a flexible boundary that absorbs the expansion pressure without transmitting damaging forces to the rigid housing and internal components of the delivery unit, thus preserving structural integrity while maintaining freezing resistance.
Solution Approach 2:
The delivery unit design incorporates sufficient headspace and flexible elements that can absorb expansion before damage occurs. The flexible membrane is pre-configured to accommodate the expected volume expansion of the liquid additive during freezing conditions, cushioning the system against damage before it can occur to rigid components.
2Ease of manufacture
If the delivery unit uses rigid housing and fixed internal components, then manufacturing is simpler and more cost-effective, but the unit cannot accommodate volume expansion during freezing
Solution Approach 1:
The patent introduces a flexible membrane into the otherwise rigid structure of the delivery unit. This membrane is relatively simple to manufacture and install, requiring minimal additional processing steps. It provides the necessary adaptability to accommodate freezing-induced volume expansion while maintaining the cost-effectiveness and manufacturing simplicity of a predominantly rigid structure.
Solution Approach 2:
The delivery unit transitions from a completely static, rigid structure to one that includes dynamic, flexible elements. The membrane can deform and adapt its shape in response to volume changes during freezing, providing the necessary versatility without significantly complicating the overall manufacturing process. The rigid housing and flexible membrane work together in a complementary manner.
3Reliability
If the delivery unit incorporates flexible elements to accommodate freezing expansion, then freezing resistance improves, but manufacturing complexity and cost increase
Solution Approach 1:
The patent uses a single flexible membrane as the primary element to accommodate freezing expansion, rather than incorporating multiple complex flexible components or mechanisms. This membrane can be integrated into the existing housing structure with minimal additional parts, maintaining relatively simple overall device complexity while achieving the necessary freezing resistance.
Solution Approach 2:
The flexible membrane serves multiple functions simultaneously: it acts as a boundary containing the liquid additive, provides a flexible interface that accommodates volume expansion during freezing, and distributes expansion pressures evenly across the structure. This multi-functionality reduces the need for separate components, thereby limiting the increase in device complexity.
4Ease of manufacture
If the delivery unit uses simple, inexpensive materials for the block and ducts, then production cost decreases, but dosing accuracy and service life may be compromised
Solution Approach 1:
The patent specifies particular material properties and dimensional parameters for the block and ducts that ensure dosing accuracy is maintained even with cost-effective materials. By carefully controlling parameters such as duct dimensions, wall thickness, and material flow characteristics, the design achieves both manufacturing economy and dosing precision without requiring expensive specialized materials.
Solution Approach 2:
The delivery unit design incorporates features that allow the system to self-regulate and maintain dosing accuracy without requiring expensive active control mechanisms. The geometric design of the ducts and chambers, combined with the flexible membrane's pressure-compensating properties, enables the system to automatically maintain precise dosing throughout its service life using passive, cost-effective means.
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 design effectively compensates for ice pressure, prevents damage from freezing, and ensures reliable, accurate dosing while being cost-effective and durable, with the plastic block and elastic sleeve-shaped element providing efficient pressure management and long service life.
Implementation Method 1
a deformable, sleeve-shaped element disposed in the collecting chamber
Implementation Method 2
typical liquid additives (such as, for example, the described urea-water solution) freeze at low temperatures. AdBlue® freezes, for example, at approximately −11° C.
Implementation Method 3
When the liquid additive freezes, a volume expansion occurs which can damage the delivery unit
Data Source
AI summary
A delivery unit for a liquid additive includes a block having at least three ducts, at least one active component mounted on the block for delivering the liquid additive, a cylindrical collecting chamber into which the at least three ducts open, and a deformable, sleeve-shaped element disposed in the collecting chamber. A motor vehicle having a delivery unit is also provided.