EGR Control System Managing Temperature and Condensate
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Solution Overview
Problem
Low pressure exhaust gas recirculation (LP-EGR) systems in engines can lead to high temperatures and condensate formation, which can degrade components like the aluminum compressor wheel of a turbocharger, while high pressure EGR systems face similar issues with temperature and condensation, necessitating a more nuanced control of EGR rates to maintain component integrity and emissions standards.
Innovation Solution
A method to control the EGR rate by considering temperature and condensate constraints at specific locations within the EGR system, such as the compressor inlet and charge air cooler, allowing for independent adjustments to maintain components below threshold temperatures and reduce condensate formation, thereby optimizing EGR rates for desirable engine operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If an EGR cooler is used to reduce gas temperature, then the temperature of components is reduced, but water condensation increases which can degrade the aluminum compressor wheel
Solution Approach 1:
The control system dynamically adjusts EGR rate parameters based on operating conditions to maintain temperature within a safe range that prevents both overheating and condensation. By changing the EGR rate parameter according to engine load and speed, the system optimizes temperature control while avoiding water condensation that would damage the compressor wheel.
Solution Approach 2:
The system uses feedback from temperature sensors and operating condition data to continuously adjust the EGR rate. This closed-loop control ensures that temperature remains within safe limits without excessive cooling that would cause condensation, thereby protecting the aluminum compressor wheel while maintaining effective heat management.
2Reliability
If a global modification to the EGR table is applied to maintain temperature and condensate levels below threshold, then component safety is improved, but the EGR rate becomes overly conservative and less than desired
Solution Approach 1:
Instead of applying a uniform conservative limit across all operating conditions, the system applies location-specific and condition-specific EGR rate adjustments. Different regions of the EGR operating map have different optimal rates based on local temperature and condensation risks, allowing maximum EGR rate utilization while maintaining component safety.
Solution Approach 2:
The EGR rate is dynamically adjusted based on real-time operating conditions rather than using a static conservative table. The system adapts the EGR rate according to engine load, speed, and temperature conditions, enabling higher productivity when conditions permit while maintaining reliability when risks are present.
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 approach allows for maintaining a desirable EGR rate while keeping engine components within safe temperature and condensate limits, reducing the risk of damage and improving emissions and fuel efficiency.
Implementation Method 1
An EGR cooler may reduce the temperature of gasses
Implementation Method 2
the cooler can also condense water out
Data Source
AI summary
Various systems and methods are described for an exhaust gas recirculation (EGR) system coupled to an engine in a vehicle. One example method comprises, controlling an amount of EGR according to a minimum of a first EGR amount corresponding to a temperature of a first location and a second EGR amount corresponding to a condensate formation of a second location.