LR-EGR Cooler Coolant Switching for Temperature Control
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Solution Overview
Problem
Current turbocharged automotive systems face challenges in designing the Long Route (LR-EGR) cooler to efficiently operate both during engine warmup and high engine loads, as it risks water condensation at low temperatures and overheating at high loads, making it difficult to extend the usage of the LR-EGR system safely across these conditions.
Innovation Solution
Incorporating a switch valve that connects the LR-EGR coolant circuit to a low temperature coolant circuit, allowing for switching between engine coolant and low temperature coolant, such as from a Water-cooled Charge Air Cooler, based on exhaust gas temperature, to manage coolant temperature and prevent overheating, with operation potentially controlled by an Electronic Control Unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the LR-EGR cooler efficiency is low to allow early activation during engine warmup, then condensation is avoided, but compressor overheating occurs at high engine loads
Solution Approach 1:
The patent applies dynamics by making the cooler efficiency variable through a switchable coolant circuit configuration. The system dynamically adjusts between a first coolant circuit (lower efficiency, higher temperature) for warmup conditions and a second coolant circuit (higher efficiency, lower temperature) for high load conditions, allowing the cooler performance to adapt to changing operational requirements rather than being fixed
Solution Approach 2:
The patent changes the parameter of coolant circuit configuration to resolve the contradiction. By switching between different coolant circuits with different thermal characteristics, the system modifies the effective cooler efficiency parameter based on operating conditions, enabling early activation during warmup while preventing compressor overheating at high loads
2Temperature
If the LR-EGR cooler efficiency is high to prevent compressor overheating at high loads, then compressor temperature is controlled, but water condensation occurs during engine warmup
Solution Approach 1:
The system dynamically switches coolant circuits based on operational phase. During warmup, the first coolant circuit with lower cooler efficiency is used to maintain higher temperatures and prevent condensation. When transitioning to high load operations, the system switches to the second coolant circuit with higher efficiency to control compressor temperature, thus adapting cooler performance to current operational needs
3Device complexity
If a single coolant circuit is used for the LR-EGR cooler, then system complexity is reduced, but the system cannot safely operate across both warmup and high load conditions
Solution Approach 1:
The patent segments the coolant supply system into multiple independent circuits (first coolant circuit and second coolant circuit), each with different thermal characteristics. This segmentation allows selective activation of appropriate circuits based on operational conditions, enabling the LR-EGR system to safely operate across both warmup and high load conditions while maintaining manageable system complexity through modular architecture
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 enables earlier activation of the LR-EGR system during engine warmup and extends its use across higher engine loads while avoiding compressor overheating, ensuring efficient operation and safe condensation prevention.
Implementation Method 1
a LR-EGR cooler (500), which is cooled by a LR-EGR coolant circuit (515)
Implementation Method 2
The switch valve (510) is configured to switch between a high temperature circuit and a low temperature circuit
Implementation Method 3
The switch valve (510) includes a bimetallic element (650) operated as a function of an exhaust gas temperature
Data Source
AI summary
A turbocharged automotive system includes an internal combustion engine and a Long Route Exhaust Gas Recirculation system connected to an exhaust line of the engine. The LR-EGR system is equipped with a LR-EGR cooler, which is cooled by a LR-EGR coolant circuit receiving coolant from an engine coolant circuit. The turbocharged automotive system further includes a low temperature coolant circuit and a connecting element for connecting the LR-EGR coolant circuit with the low temperature coolant circuit bypassing the engine coolant circuit.