Layered Tank Wall for Urea Dosing Heater Protection
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Solution Overview
Problem
Existing dosing devices for pollutant-reducing media in exhaust gas treatment face challenges with frost resistance, particularly with urea-water solutions like AdBlue, which freeze at low temperatures, and require complex heater protection and inefficient heat transfer due to plastic tank materials.
Innovation Solution
A dosing device with a layered storage tank structure featuring a protective layer, a heating layer with a flat PTC heater, and an outer layer for mechanical strength and thermal insulation, where the heating element is externally contacted to ensure efficient heat transfer to the medium while being shielded from the pollutant-reducing medium.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the heater is mounted on the outer surface of the plastic tank, then the heater is protected from the medium, but the thermal conductivity of the plastic represents a clear barrier to heat transport
Solution Approach 1:
The tank wall is divided into multiple functional layers: an inner protective layer that shields the heater from the medium, intermediate layers for structural support, and an outer insulating layer. This segmentation allows each layer to optimize its specific function while working together to achieve both heater protection and efficient heat transport.
Solution Approach 2:
The tank wall employs a composite structure combining materials with different properties: the inner layer uses chemically resistant material to protect against the medium, while the outer layer uses thermally insulating material to maintain temperature. This composite approach resolves the contradiction between protection and heat efficiency.
2Use of energy by moving object
If the heater is placed inside the tank, then heat transport is improved, but the heater must be protected against the liquid HWL and against ice pressure by means of complex protective measures
Solution Approach 1:
The inner tank wall layer acts as an intermediary between the heater and the urea-water solution. This intermediary layer provides both chemical resistance and mechanical strength, protecting the heater from the medium and ice pressure without requiring complex protective measures while maintaining efficient heat transport.
3Use of energy by moving object
If high temperature differences between the tank wall outside and inside are used, then high heat transport is enabled, but the temperature limits of the plastic prevent this
Solution Approach 1:
The multi-layer tank wall structure uses materials with appropriate thermal properties to manage temperature gradients. The inner layer handles chemical resistance at moderate temperatures, while the outer insulating layer maintains the temperature difference needed for efficient heat transport without exceeding material temperature limits.
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 provides effective heating of pollutant-reducing media at low temperatures with improved thermal efficiency and mechanical strength, preventing damage from the medium and ensuring reliable operation in cold conditions.
Implementation Method 1
The heating element is designed in particular as a printed heating element, in particular as a PTC heating element
Implementation Method 2
at least one outer layer (126) which is assigned to the outside (118) of the tank (112)
Data Source
Figure 1
AI summary
The invention relates to a dosing device (110) for introducing a pollutant-reducing medium (114), in particular a reducing agent and/or a reducing agent precursor, into an exhaust gas which flows through a flow pipe. The dosing device (110) comprises a supply system for providing the pollutant-reducing medium (114) having at least one reserve tank (112) for receiving a reserve of the pollutant-reducing medium (114). The reserve tank (112) has a tank wall (116). The tank wall (116) has a layered construction, having at least one protective layer (122), which faces toward a tank inner side (120), at least one heating layer (124), and at least one outer layer (126), which faces toward a tank outer side (118).