Elevated Fastener Brackets for Doser Thermal Isolation
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Solution Overview
Problem
Existing emission control systems for diesel engines face challenges due to high heat and mechanical stress, leading to failures in doser systems used for reducing NOx emissions, which are exacerbated by the durability and serviceability issues related to the placement of these components.
Innovation Solution
A doser mounting system with a thermal isolator and elevated fastener brackets that maintain an air gap between the fastener head and the mounting plate, reducing heat transfer and incorporating low thermal conductivity materials like mica to prevent overheating and mechanical stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the doser system is placed close to the engine exhaust components, then the system can effectively treat emissions, but the components are subjected to excessive heat and mechanical stress leading to failure
Solution Approach 1:
A thermal isolator is introduced as an intermediary component between the doser mounting system and the exhaust component. This thermal isolator reduces heat transfer from the exhaust component to the doser system, thereby protecting the doser system from excessive heat while maintaining its proximity to the exhaust for effective emissions treatment.
Solution Approach 2:
The mounting system is segmented into distinct components: a mounting plate, fastener brackets, and a thermal isolator. This segmentation allows the thermal isolator to be specifically positioned between the exhaust heat source and the doser system, providing targeted thermal protection while maintaining the overall compact structure.
2Reliability
If the doser system is placed close to the engine exhaust components, then the system can effectively treat emissions, but the components are subjected to mechanical stress and vibrations leading to failure
Solution Approach 1:
The thermal isolator also serves as a mechanical buffer between the exhaust component and the doser system. This intermediary structure absorbs and isolates mechanical stress and vibrations from the exhaust environment, protecting the doser system components from mechanical failure while maintaining effective proximity for emissions treatment.
3Device complexity
If traditional mounting methods are used, then the structure is simple, but the fasteners are exposed to high heat causing thermal expansion and potential failure
Solution Approach 1:
The thermal isolator acts as a thermal barrier between the hot exhaust component and the fasteners. This intermediary structure reduces heat transfer to the fasteners, preventing thermal expansion and potential failure while maintaining a relatively simple mounting system structure.
Solution Approach 2:
The fastener brackets are elevated above the mounting plate surface, creating a spatial dimension that positions fasteners away from the primary heat source. This dimensional change allows fasteners to be protected from excessive heat while maintaining the structural integrity of the mounting system.
4Device complexity
If the fastener head is in direct contact with the mounting plate, then the structure is compact, but heat transfer to the fastener head causes thermal stress
Solution Approach 1:
The fastener brackets are elevated above the mounting plate surface, creating a spatial gap that positions the fastener heads away from the hot mounting plate. This dimensional change reduces direct heat transfer to the fastener heads, preventing thermal stress while maintaining a relatively compact overall structure.
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 heat-related failures and improves the reliability and serviceability of the doser system by maintaining lower temperatures and withstanding severe vibrations, thus enhancing the durability and performance of the selective catalytic reduction system.
Implementation Method 1
The thermal isolator is composed of low thermal conductive material such as mica
Implementation Method 2
an air gap is maintained between the head of the fastener and the surface of the mounting plate
Data Source
AI summary
A system and method for providing a selective catalytic reduction system with a doser mounting system. A mounting plate includes an aperture in a surface with a plurality of fastener brackets coupled to the surface. The fastener brackets are positioned about a peripheral portion of the aperture. The fastener brackets each include an opening for inserting a fastener. The opening is elevated from the surface of the mounting plate. The fasteners each have a fastener head and a fastener shaft positioned in the opening of the fastener brackets. The fastener shaft extends from the opening in a direction having an orthogonal component with respect to the surface of the mounting plate. A doser is coupled to the doser mounting system. The fastener shafts extend through openings in legs of the doser. An injector port of the doser is aligned with the aperture in the mounting plate.