EGR Cooler Effectiveness Modeling for Deposit Mitigation

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

EGR cooler effectiveness decreases due to deposits forming on its inner walls, reducing heat dissipation and requiring continuous adjustments to maintain NOx reduction and engine performance, especially under intermittent engine operation.

Innovation Solution

A method of modeling EGR cooler effectiveness using temperature measurements and operational history to predict condensate formation and adjust EGR flow and temperature control, incorporating ambient conditions to maintain stable performance and prevent acidic material introduction into the engine cylinder.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If EGR cooler operates continuously, then cooling capacity is maintained, but deposits accumulate and reduce heat dissipation effectiveness

Engineering Contradiction:

Improvecooler effectivenessVSAvoidheat dissipation

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The system implements periodic engine shutdowns during intermittent operation cycles, allowing condensate to form and flush deposits from the cooler walls. This periodic cleaning action restores heat transfer effectiveness without requiring continuous operation, resolving the contradiction between maintaining cooling capacity and preventing deposit accumulation.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The system converts the harmful effect of condensate formation during shutdowns into a beneficial cleaning mechanism. The condensate that would normally be considered a harmful byproduct is instead utilized to flush and remove deposits from the cooler interior surfaces, thereby restoring heat dissipation effectiveness and converting a negative factor into a positive cleaning action.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Productivity

If engine operates intermittently, then fuel economy improves, but cooler effectiveness varies and requires continuous adjustment

Engineering Contradiction:

Improvefuel economyVSAvoidcooler performance stability

Core Design Contradiction:

ProductivityVSEase of operation

Solution Approach 1:

The system employs a control unit that continuously monitors cooler effectiveness and adjusts EGR flow rates based on feedback from temperature sensors and operational history. This closed-loop control compensates for performance variations caused by intermittent operation, maintaining stable NOx reduction despite varying fuel economy conditions.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system uses operational history tracking to predict when deposit accumulation will significantly impact performance. By monitoring shutdown durations and operational patterns in advance, the control unit can proactively adjust EGR flow rates before effectiveness degrades, preventing performance instability rather than reacting to it after the fact.

Inventive Principle:

Principle #10Preliminary action

3Object-affected harmful factors

If EGR flow is increased to maintain NOx reduction, then emissions control improves, but engine throttling increases and performance decreases

Engineering Contradiction:

ImproveNOx reductionVSAvoidengine performance

Core Design Contradiction:

Object-affected harmful factorsVSProductivity

Solution Approach 1:

The system dynamically adjusts EGR flow rates based on real-time cooler effectiveness parameters derived from temperature measurements and operational history. By optimizing the EGR flow parameter according to actual cooler performance rather than using fixed high flow rates, the system maintains effective NOx reduction while minimizing unnecessary engine throttling and preserving performance.

Inventive Principle:

Principle #35Parameter changes

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

The model stabilizes EGR cooler performance, reduces engine throttling, and extends engine life by predicting and mitigating deposit formation, ensuring consistent NOx reduction and improved heat exchange characteristics.

Implementation Method 1

EGR coolers are designed with a certain heat transfer capacity to achieve the degree of cooling required to maintain the system's thermodynamic effectiveness

Methodology Applied

Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

The recirculated exhaust is often cooled using liquid or air coolant as a cooling medium

Methodology Applied

Scientific EffectConvection: Convection

Implementation Method 3

as exhaust continues to flow through the EGR cooler, deposits form and accumulate on the inside wall of the cooler

Methodology Applied

Scientific EffectDeposition: Deposition (physical)

Implementation Method 4

The model includes the relationship between EGR cooler effectiveness and engine shutdowns and re-starts

Methodology Applied

Scientific EffectCondensation: Condensation

Data Source

PatentUS8725386B2Effectiveness modeling and control methods for EGR cooler

Publication Date: 2014.05.13 SOUTHWEST RES INST

AI summary

A method of modeling and testing the effectiveness of an EGR cooler. The cooler effectiveness is mathematically modeled as a function of various temperatures and over an operation history that includes one or more engine shut-downs.