Modular EGR Cooler Segmentation for Fouling Control
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Solution Overview
Problem
Current exhaust gas recirculation (EGR) systems in internal combustion engines face issues with fouling due to varying EGR flows and exhaust temperatures, leading to either overcooling or inadequate cooling, which can result in pumping losses and reduced emissions benefits.
Innovation Solution
The implementation of a multi-module EGR system with cooler and bypass portions, each equipped with a flow control device, allows for selective cooling or bypassing of exhaust gas, ensuring the exhaust recirculation gas temperature remains above the critical level, thereby preventing fouling and optimizing engine performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a single EGR cooler is designed to meet maximum cooling requirements, then cooling capacity is sufficient at high EGR flow and high exhaust temperature, but the cooler exit temperature drops below the critical temperature at lower EGR flow and lower exhaust temperature, causing fouling
Solution Approach 1:
The single EGR cooler is divided into multiple cooler modules (first cooler module, second cooler module, etc.), each capable of independent operation. This segmentation allows the system to provide appropriate cooling capacity for different operating conditions without overcooling, thereby preventing fouling while maintaining reliable emissions reduction across the full range of EGR flows and exhaust temperatures.
Solution Approach 2:
The system incorporates flow control devices (such as valves) that dynamically adjust the distribution of exhaust recirculation gas among different cooler modules based on operating conditions. This dynamic control ensures that the cooler exit temperature remains above the critical temperature across varying EGR flows and exhaust temperatures, preventing fouling while maintaining effective cooling when needed.
2Reliability
If a bypass is used to prevent overcooling, then fouling is reduced, but the exhaust recirculation gas may be at an undesirably high temperature during some operating conditions
Solution Approach 1:
By segmenting the EGR cooling system into multiple cooler modules with independent flow control, the system can selectively activate only the necessary number of coolers based on operating conditions. This avoids the need for a bypass while preventing both overcooling and insufficient cooling, as each module can be independently controlled to provide the exact cooling needed.
Solution Approach 2:
The system changes the operational parameters (which cooler modules are active and their individual flow rates) based on operating conditions such as EGR flow rate and exhaust temperature. This allows precise control of the exhaust recirculation gas temperature to remain within the optimal range, preventing both fouling and excessive temperature without requiring a bypass.
3Reliability
If the exhaust recirculation gas temperature increases to match varying EGR flows, then fouling is prevented, but pumping losses increase and the turbocharger must work harder
Solution Approach 1:
The system dynamically adjusts the cooling provided by individual cooler modules based on real-time operating conditions. By providing cooling only when and where needed, the system maintains exhaust recirculation gas temperature above the critical level to prevent fouling, while minimizing unnecessary cooling that would increase pumping losses and turbocharger workload.
Solution Approach 2:
The system changes the cooling parameters (activation and flow rate of cooler modules) to match the actual cooling demand at different operating conditions. This ensures the exhaust recirculation gas temperature is maintained within the optimal range, preventing fouling without excessive temperature increase that would lead to energy losses.
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 solution effectively maintains the exhaust recirculation gas temperature above the critical level, reducing fouling and optimizing engine performance by matching cooling needs with varying EGR flows and temperatures, thus enhancing fuel economy and emission reduction.
Implementation Method 1
The cooler portion cools fluid flowing therethrough
Data Source
AI summary
An EGR system compensates for differing EGR flows and/or exhaust temperatures and can maintain the cooler exit temperature above the critical temperature, thereby reducing the possibility of EGR cooler fouling. A plurality of exhaust gas recirculation cooler modules is disposed between an exhaust gas passage and an air passage. The cooler modules receive exhaust gas from the exhaust gas passage and supply the received exhaust gas to the air passage for recirculation into an intake manifold. Each of the cooler modules includes a cooler portion, a bypass portion, and a flow control device. The cooler portion and the bypass portion are arranged such that fluid flowing through the cooler portion and the bypass portion flows therethrough without flowing through the other of the cooler portion and the bypass portion. The cooler portion reduces a temperature of the fluid flowing through the cooler portion.