Exhaust Gas Recirculation Device With Segmented Heat Exchanger
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Solution Overview
Problem
Existing exhaust gas recirculation devices are not suitable for low-pressure operation due to high resistance in the exhaust gas recirculation channel, leading to insufficient controllability of recirculated exhaust gas flow and inability to meet legal emission standards, especially at low-pressure ranges.
Innovation Solution
The exhaust gas recirculation device features two structurally separate strands connected via a collector, with a flap valve that regulates exhaust gas flow through the heat exchanger, allowing for adjustable flow direction and reduced resistance, enabling efficient thermal energy recovery even at high recirculation rates and low pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If exhaust gas flows through a conventional exhaust gas recirculation duct with high resistance, then thermal energy can be recovered through the heat exchanger, but the device becomes unsuitable for low-pressure operation and cannot meet emission standards
Solution Approach 1:
The exhaust gas recirculation duct is divided into two separate strands (first strand and second strand) that are structurally separated. This segmentation reduces the resistance in each individual strand compared to a single duct, allowing exhaust gas to flow more easily while still enabling effective heat exchange. The collector combines the flows from both strands, maintaining the necessary recirculation rate without requiring high pressure.
2Object-generated harmful factors
If the exhaust gas recirculation rate is increased to meet emission standards, then pollutant emissions are reduced, but the resistance in the exhaust gas recirculation duct increases making the device unsuitable for low-pressure operation
Solution Approach 1:
By segmenting the recirculation path into two parallel strands with a collector, the system can achieve high recirculation rates without proportionally increasing resistance. Each strand handles a portion of the flow, reducing individual strand resistance and allowing the system to meet emission requirements while maintaining low-pressure operation capability.
Solution Approach 2:
The flap valve provides dynamic control over the exhaust gas flow distribution between the two strands and the direct exhaust path. This dynamic adjustment capability allows the system to optimize recirculation rates according to operating conditions, meeting emission standards when necessary while maintaining simplicity and adaptability.
3Device complexity
If a single exhaust gas recirculation duct is used, then the device structure is simpler, but the flow gradient must be sufficiently high to ensure adequate exhaust gas flow through the heat exchanger
Solution Approach 1:
The dual-strand configuration with collector provides two parallel flow paths that collectively offer lower resistance than a single duct. This segmentation allows adequate exhaust gas flow speed through the heat exchanger without requiring a steep flow gradient, while the overall structure remains relatively simple and manageable.
4Ease of operation
If the exhaust gas duct is closed in the region between the two branches, then exhaust gas flow can be directed through the first branch upstream, but the flap valve must be continuously adjustable between multiple positions
Solution Approach 1:
The flap valve is designed with continuous adjustability between multiple positions (fully open, intermediate positions, fully closed between branches). This dynamic adjustment capability provides ease of operation by allowing flexible flow direction control according to various operating conditions, while the mechanical design keeps the adjustment mechanism practical and manageable.
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
This design allows for efficient thermal energy recovery and improved controllability of exhaust gas recirculation, meeting emission standards across various operating conditions, including low-pressure ranges, by optimizing the flow through the heat exchanger and reducing cooling requirements.
Implementation Method 1
a heat exchanger, which cools the recirculated exhaust gas, thus reducing pollutant emissions after the cold start phase
Implementation Method 2
This thermal energy can be used, for example, to heat the internal combustion engine more quickly, to warm the driver's cab more quickly, or to reduce friction losses by heating the lubricant system
Data Source
Figure 1~4
Figure 5~6
AI summary
The present invention relates to an exhaust gas recirculation device (10) for an internal combustion engine comprising an exhaust gas duct (14), an inlet duct (22) and a heat exchanger (30) which can be connected fluidically at one end to the exhaust gas duct (14) and which can be connected fluidically at an opposite end to an exhaust gas recirculation duct (34) which opens into the inlet duct (22). The heat exchanger (30) has two sections (42, 44) which are separated structurally from one another and open into a manifold (46) which is connected fluidically to the exhaust gas recirculation duct (34). An exhaust gas recirculation valve (50) is arranged in the exhaust gas recirculation duct (34). Furthermore, the exhaust gas recirculation device (10) has a flap valve (54) which is arranged in the exhaust gas duct (14) in such a way that the flap valve (54) opens the exhaust gas duct (14) in a first position, and closes the exhaust gas duct (14) in the flow direction downstream of the two sections (42, 44) in a second position, with the result that the exhaust gas stream flows through the two sections (42, 44) in the direction of the exhaust gas recirculation duct (34), and the flap valve (54) closes the exhaust gas duct (14) in the region between the two sections (42, 44) in a third position, with the result that the exhaust gas stream can be conducted through the first section (44) which is arranged upstream in the exhaust gas direction, and the second section (42) can be flowed through in the opposite direction in a manner which is dependent on the position of the exhaust gas recirculation valve (50).