Water-Cooled EGR Cooler Bubble Removal and Thermal Deformation Control

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Solution Overview

Problem

Existing EGR coolers made of stainless materials are heavy, have low heat transfer efficiency, poor moldability, and are expensive, while those made of aluminum are prone to thermal deformation and coolant leaks due to bubble formation, affecting cooling performance and engine reliability.

Innovation Solution

A water-cooled EGR cooler design featuring a housing with a heat exchange member and bypass passages to facilitate smooth coolant flow and bubble removal, using aluminum materials for the heat exchange member, upper, and lower boards, with brazed connections and strategically formed gaps to manage coolant flow and prevent thermal deformation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an EGR cooler is made of stainless material, then corrode resistance is improved, but weight increases and heat transfer efficiency decreases

Engineering Contradiction:

Improvecorrode resistanceVSAvoidweight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The EGR cooler employs a composite structure combining aluminum alloy (for heat exchange components requiring high heat transfer efficiency) and stainless steel (for components requiring high corrode resistance). Specifically, the heat exchange member is made of aluminum alloy while the housing and certain structural components use stainless steel, creating an optimized composite material solution that balances both corrosion resistance and weight reduction.

Inventive Principle:

Principle #40Composite materials

2Temperature

If an EGR cooler is made of aluminum material, then heat transfer efficiency is improved, but thermal deformation resistance decreases

Engineering Contradiction:

Improveheat transfer efficiencyVSAvoidthermal deformation resistance

Core Design Contradiction:

TemperatureVSStability of the object's composition

Solution Approach 1:

Different regions of the EGR cooler are assigned different materials based on their specific functional requirements. The heat exchange member (exhaust gas passages and coolant passages) is made of aluminum alloy for high heat transfer efficiency, while the housing and structural support components are made of stainless steel for high thermal deformation resistance. This local quality differentiation allows each component to optimize its performance for its specific function.

Inventive Principle:

Principle #3Local quality

3Ease of operation

If coolant inlet is at the lower portion and outlet is at the upper portion, then bubble discharge is improved, but thermal deformation resistance decreases

Engineering Contradiction:

Improvebubble dischargeVSAvoidthermal deformation resistance

Core Design Contradiction:

Ease of operationVSStability of the object's composition

Solution Approach 1:

The EGR cooler is divided into multiple functional segments: the housing provides structural support and thermal deformation resistance, while the heat exchange member (separated into exhaust gas passages and coolant passages) provides heat transfer functionality. The coolant passage is specifically designed with inlet at the lower portion and outlet at the upper portion to facilitate bubble discharge, while the housing structure compensates for thermal deformation through its material properties and structural design.

Inventive Principle:

Principle #1Segmentation

4Ease of manufacture

If aluminum material is used for heat exchange member, then cost is reduced, but reliability against thermal deformation decreases

Engineering Contradiction:

ImprovecostVSAvoidthermal deformation resistance

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

Inventive Principle:

Principle #40Composite materials

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

Stably removes coolant bubbles, maintains cooling performance, and prevents engine failure by reducing thermal deformation and leaks, enhancing the overall efficiency and cost-effectiveness of the EGR cooler.

Implementation Method 1

a heat exchange member (110) disposed in the housing (130) and provided with exhaust gas passages from the inlet (102) to the outlet (112)

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

a coolant passage through which a coolant flows from an inlet of a lower portion to an outlet of an upper portion between the exhaust gas passages

Methodology Applied

Scientific EffectConvection: Convection

Data Source

PatentUS10087893B2Water-cooled EGR cooler

Publication Date: 2018.10.02 HYUNDAI MOTOR CO LTD

AI summary

A water-cooled EGR cooler is to be supplied with exhaust gas from an exhaust line and is to re-circulate the cooled exhaust gas to an intake line. A housing has an exhaust inlet, an exhaust outlet, a coolant inlet, and a coolant outlet. A heat exchange member is disposed in the housing and includes exhaust gas passages from the exhaust inlet to the exhaust outlet at a predetermined interval and also includes a coolant passage through which coolant can flow from the coolant inlet to the coolant outlet between the exhaust gas passages. A pipe member includes a bypass passage formed between an upper surface of the heat exchange member and an inside upper surface of the housing to allow the exhaust gas to bypass the heat exchange member and flow between the upper surface of the heat exchange member and the coolant outlet.