Dosing Module Air Gap Insulation for Thermal Management
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Solution Overview
Problem
Existing exhaust gas aftertreatment systems face challenges in withstanding high thermal loads during internal combustion engine operation, leading to potential overheating and damage.
Innovation Solution
A dosing module with a multi-part heat sink housing that incorporates air gap insulation and water cooling, using a hybrid component design with separate areas for cooling fluid flow and air gap insulation to minimize sealing points and accommodate different thermal expansion coefficients, while ensuring effective cooling and protection against temperature shocks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the dosing module is exposed to high thermal loads during engine operation, then the reducing agent can be effectively injected into the exhaust stream, but the dosing module components may overheat and suffer thermal damage
Solution Approach 1:
The housing is divided into multiple shells (first shell, second shell, third shell) that can be assembled together. This segmentation allows each shell to be optimized for specific thermal functions - the first shell provides structural support, the second shell incorporates cooling channels, and the third shell provides additional protection. The segmented design enables targeted thermal management without requiring the entire housing to be complex.
Solution Approach 2:
A cooling medium is introduced as an intermediary substance that flows through channels in the housing shells. This cooling medium acts as a thermal mediator, absorbing excess heat from the dosing module components and transporting it away from the critical areas. The cooling medium enables effective heat management without direct contact between the hot exhaust gases and the dosing module electronics.
2Temperature
If cooling channels are incorporated into the housing, then thermal management is improved, but the housing structure becomes more complex and requires more sealing points
Solution Approach 1:
The cooling channels are merged directly into the housing shells themselves, rather than being separate components. The first, second, and third shells are designed with integrated cooling passages that allow the cooling medium to flow through the housing structure. This merging eliminates the need for separate cooling components and reduces the number of interfaces requiring sealing.
Solution Approach 2:
The housing shells serve multiple functions simultaneously: they provide structural support for the dosing module, contain the cooling channels for thermal management, and act as thermal barriers. The first shell provides structural integrity, the second shell with its cooling channels provides thermal management, and the third shell provides additional protection. This multi-functionality reduces the overall number of components needed.
3Temperature
If the housing material is chosen to withstand high temperatures, then thermal resistance is improved, but the material may have high thermal expansion coefficients causing stress from thermal expansion differences
Solution Approach 1:
Different regions of the housing are designed with different material properties to match local thermal requirements. The first shell uses a material optimized for structural strength and thermal resistance, while the second and third shells use materials with appropriate thermal expansion characteristics. This local quality differentiation allows each region to perform its specific function while minimizing overall thermal expansion stress.
Solution Approach 2:
The housing design explicitly accounts for thermal expansion by using materials with appropriate coefficients of thermal expansion for each shell. The first shell material is selected for high-temperature stability, while subsequent shells use materials that can accommodate thermal expansion differences. This thermal expansion consideration prevents stress concentration at the interfaces between different housing shells during temperature cycling.
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 cools the dosing module, including the area around the outlet opening for the reducing agent, and other critical areas, providing thermal mass for delayed heating and preventing damage from temperature peaks, while avoiding electrical short circuits and stress from thermal expansion differences.
Implementation Method 1
air gap insulation can be implemented, for example, which protects against overheating damage
Implementation Method 2
a cooling fluid flows, in particular for cooling an injection valve for the reducing agent
Implementation Method 3
the dosing element is surrounded by a heat sink which—comprising several parts—completely encloses the dosing valve
Data Source
AI summary
The invention relates to a device for cooling a metering module (10), in particular a module for metering an operating agent/auxiliary agent such as a reducing agent into the exhaust gas system of an internal combustion engine. A cooling device comprising a cooling member (17, 20, 24, 28, 29) through which a cooling liquid flows is associated with the metering module (10). The cooling member (17, 20, 24, 28, 29) acts as a housing (12) for the metering module (10). A first group of parts (17, 20, 28) forms an air gap insulation (38; 54, 56, 58) on an electric contact (16, 36), while cooling fluid flows through a second group of parts (28, 29, 40).