EGR Cooler Condensate Control via Flow Modulation
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Solution Overview
Problem
Existing engine heat exchangers face issues with condensate accumulation, which can lead to misfires and component degradation due to the difficulty in predicting condensation and the complexity of bypass systems, especially in exhaust gas recirculation coolers where acidic compounds are present.
Innovation Solution
A method that increases exhaust gas recirculation (EGR) flow responsive to condensation in EGR coolers by estimating the accumulated condensate based on formed and evaporated condensate, allowing for accurate determination and removal without a complicated bypass system, using a condensation model that considers operating parameters like EGR rate, boost pressure, and mass air flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a bypass line is provided around the heat exchanger to prevent condensate accumulation, then condensate accumulation is prevented, but device complexity and cost increase
Solution Approach 1:
The patent extracts the condensate removal function from the main EGR flow path by implementing a separate condensate drain system with drain valves positioned at the lowest points of the heat exchanger. This allows condensate to be removed independently without requiring a complex bypass line around the entire heat exchanger, thereby preventing condensate accumulation while minimizing device complexity.
Solution Approach 2:
The patent introduces condensate drain valves as intermediary components that mediate between the heat exchanger and the external environment. These valves act as controlled access points for condensate removal, enabling effective condensate management without the need for a comprehensive bypass system, thus resolving the contradiction between reliability and device complexity.
2Reliability
If a bypass line is used to avoid condensate deposition, then condensate accumulation is prevented, but manufacturing cost increases
Solution Approach 1:
The patent extracts only the essential condensate removal function from the expensive bypass line concept, implementing a simplified system using existing heat exchanger low points and adding only necessary drain valves and piping. This approach prevents condensate accumulation while significantly reducing manufacturing cost compared to a full bypass line installation.
Solution Approach 2:
The patent employs relatively simple and inexpensive drain valves and short drain lines as disposable-like components that can be easily manufactured and installed. These low-cost components effectively perform condensate removal without the high manufacturing cost associated with complex bypass systems, resolving the contradiction between reliability and ease of manufacture.
3Reliability
If bypass is activated based on inaccurate condensation prediction, then condensate accumulation may be prevented, but charge air temperature increases and density decreases
Solution Approach 1:
The patent implements preliminary action by proactively removing condensate through drain valves before it can accumulate to harmful levels and cause misfires. This preventive approach eliminates the need for reactive bypass activation based on condensation predictions, thereby maintaining charge air density and productivity while still preventing condensate accumulation.
Solution Approach 2:
The patent enables the heat exchanger to serve itself by incorporating self-draining capabilities through strategically positioned drain valves at the lowest points. The system automatically removes condensate through gravity drainage without requiring external bypass control systems or complex prediction algorithms, thus maintaining charge air quality and engine productivity while preventing condensate-related issues.
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 effectively prevents condensate accumulation in engine heat exchangers, reducing the risk of misfires and component degradation while simplifying the engine control system by accurately tracking and removing condensate, thus maintaining engine efficiency and component integrity.
Implementation Method 1
when the air in the heat exchanger is cooled below its dew point, condensate can form within the heat exchanger
Implementation Method 2
exhaust gas recirculation coolers which cool exhaust being recirculated back to the intake
Data Source
AI summary
Embodiments for controlling condensate in an engine heat exchanger are disclosed. In one example, a method for an engine comprises increasing exhaust gas recirculation (EGR) flow responsive to condensation in an EGR cooler. In this way, condensate in the EGR cooler may be controlled via modulation of EGR flow.