EGR Valve Integration in Exhaust Manifold
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Solution Overview
Problem
Existing EGR systems face issues with thermal degradation of valve assemblies, high costs, and increased losses due to complex valve configurations, which affect engine compactness and efficiency.
Innovation Solution
An engine design incorporating a valve adjustment system with cam profile switching (CPS) devices to selectively control exhaust gas flow between an EGR conduit and an exhaust system using dedicated cylinder valves and conduits, eliminating the need for external valve assemblies and allowing for improved combustion efficiency and reduced emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If valve assemblies are used to regulate exhaust flow to EGR conduit and exhaust system, then exhaust gas flow can be controlled, but the valve assemblies are susceptible to thermal degradation from high temperature exhaust gases
Solution Approach 1:
The patent removes the EGR valve from the hot exhaust gas path by routing exhaust gases through a cooler pathway to the EGR conduit. The valve is positioned in the cooler EGR conduit rather than in the hot exhaust manifold or exhaust system, extracting it from the high-temperature environment that causes thermal degradation.
2Ease of operation
If multiple valve assemblies are used to control exhaust flow, then exhaust gas recirculation can be regulated, but the EGR valves increase engine cost
Solution Approach 1:
The exhaust manifold serves multiple functions: it collects exhaust gases from all cylinders and also acts as the housing for the EGR valve. This multi-functionality eliminates the need for separate EGR valve housings and reduces the number of components required, thereby reducing manufacturing cost.
Solution Approach 2:
The patent combines the EGR valve assembly with the exhaust manifold structure. The EGR valve is integrated into the exhaust manifold housing, merging two separate components into one unified assembly, which reduces part count and manufacturing complexity.
3Ease of operation
If valve assemblies are installed in EGR conduits, then exhaust gas flow can be regulated, but losses in the EGR conduit and exhaust system increase
Solution Approach 1:
The EGR valve is extracted from the main exhaust flow path and placed in a separate, dedicated EGR conduit. This allows the main exhaust system to remain unobstructed while EGR gases are diverted through a separate pathway, minimizing flow restrictions and energy losses in both the EGR conduit and the main exhaust system.
4Ease of operation
If complex valve networks are used for EGR control, then exhaust gas flow can be managed, but the engine compactness is decreased
Solution Approach 1:
The EGR valve housing is merged with the exhaust manifold structure, eliminating the need for separate EGR valve housings and mounting brackets. This integration reduces the overall space required for EGR components and maintains engine compactness.
Solution Approach 2:
The exhaust manifold serves as both the exhaust collection system and the housing for the EGR valve assembly. This multi-functionality eliminates the need for dedicated EGR valve housings and reduces the number of separate components, thereby maintaining compact engine packaging.
Data Source
AI summary
An engine is provided that includes an exhaust gas recirculation (EGR) conduit in fluidic communication with a first exhaust valve in a cylinder and an intake system, an exhaust conduit in fluidic communication with a second exhaust valve in the cylinder and an emission control device. During operation with the first valve active and the second valve deactivated, a fixed EGR level can be provided. However, during operation with the first valve deactivated and the second valve active, increased engine output can be achieved with reduced EGR without requiring additional exhaust throttling or switching valves.