EGR Cooler Barrier Layer Prevents Varnish Deposition
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Solution Overview
Problem
Standard EGR cooler designs fail to effectively prevent the deposition of hydrocarbons and soot, which form a varnish that reduces the cooler's effectiveness, restricts airflow, and causes corrosion, leading to increased NOx emissions.
Innovation Solution
An EGR cooler with a barrier layer, comprising a refractory solid oxide and platinum group metals or mixed metal oxides, is applied to prevent the accumulation of varnish on components, allowing for efficient heat transfer while preventing hydrocarbon and soot deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a standard EGR cooler design is used, then the structure is simple and manufacturing is easy, but varnish deposits form on components reducing cooler effectiveness and causing corrosion
Solution Approach 1:
A barrier layer is introduced as an intermediary substance between the exhaust gases and the cooler components. This barrier layer prevents direct contact between the varnish-forming hydrocarbons and the cooler surfaces, thereby preventing varnish deposition while maintaining the basic cooler structure and effectiveness.
Solution Approach 2:
The barrier layer is formed from a composite material containing a refractory solid oxide and a platinum group metal or mixed metal oxide. This composite structure provides both the thermal stability needed to withstand exhaust temperatures and the catalytic activity needed to prevent varnish formation, resolving the contradiction between maintaining cooler effectiveness and preventing deposition.
2Productivity
If the EGR cooler operates without a barrier layer, then the device complexity is low, but hydrocarbons and soot accumulate forming varnish that restricts airflow
Solution Approach 1:
The barrier layer serves as an intermediary that prevents varnish accumulation on cooler surfaces. By eliminating this deposition barrier, airflow remains unrestricted and productivity is maintained without requiring complex additional components or structures.
3Reliability
If no barrier layer is used, then the manufacturing process is simple, but corrosion of components occurs due to acidity of soot
Solution Approach 1:
The barrier layer acts as a protective intermediary between the acidic soot and the cooler components. This prevents direct corrosive interaction while maintaining the relatively simple cooler structure, thereby improving component durability without significantly increasing device complexity.
Solution Approach 2:
The composite material comprising refractory solid oxide and platinum group metal or mixed metal oxide provides both corrosion resistance and catalytic activity. This composite structure protects components from acidic soot while maintaining the simplicity of the overall cooler design.
4Reliability
If the barrier layer is applied to all surfaces, then protection is maximized, but the package size increases
Solution Approach 1:
The barrier layer is applied selectively to specific surfaces where varnish deposition is most problematic, rather than coating all surfaces uniformly. This localized application provides adequate protection effectiveness while minimizing the increase in package size.
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 barrier layer enhances the EGR cooler's effectiveness, reducing NOx emissions, minimizing airflow restriction, and preventing corrosion, thereby maintaining the cooler's performance and reducing the overall package size of emissions equipment.
Implementation Method 1
allowing sufficient heat transfer between exhaust gases and the cooling medium
Implementation Method 2
The catalytic barrier layer may include a refractory solid oxide and a platinum group metal or mixed metal oxide to prevent accumulation of varnish material deposited onto EGR cooler components
Implementation Method 3
exhaust gases may be at higher temperature and aid in burning off hydrocarbons and soot preventing varnish formation
Data Source
AI summary
Aspects of the disclosure relate to providing an EGR cooler including a barrier layer applied to EGR cooler components while allowing sufficient heat transfer between exhaust gases and the cooling medium. A barrier layer may be applied onto particular surfaces of the EGR cooler components to prevent deposition of hydrocarbons or soot on the EGR cooler components. In some arrangements, the barrier layer may comprise a refractory solid oxide. In other arrangements, an EGR cooler may comprise a catalytic barrier layer. The catalytic barrier layer may include a refractory solid oxide and a platinum group metal or mixed metal oxide to prevent accumulation of varnish material deposited onto EGR cooler components.