End Plate Expansion Slots for Heat Exchanger Thermal Distortion

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Solution Overview

Problem

Heat exchangers in motor vehicles experience distortions and reduced service life due to thermal cycling and inhomogeneous temperature distributions, primarily caused by the difference in stiffness and thermal inertia between thicker end plates and thinner intermediate plates.

Innovation Solution

The heat exchanger design includes end plates with expansion zones, such as recesses, to reduce stiffness and mass, and optionally a reinforcing plate, which helps to align the stiffness of end and intermediate plates, minimizing distortion and stress, and features turbulence inserts for improved heat transfer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If end plates are made thicker to increase stiffness and strength, then structural strength is improved, but thermal inertia increases causing slower heating and cooling rates which leads to greater distortions during thermal cycling

Engineering Contradiction:

Improvestructural strengthVSAvoidthermal response time

Core Design Contradiction:

StrengthVSDuration of action of moving object

Solution Approach 1:

The end plates are designed with non-uniform thickness, featuring a thicker first region for structural strength and a thinner second region for faster thermal response. This local variation in thickness allows different parts of the same component to serve different functions - the thicker portion provides stiffness while the thinner portion reduces thermal inertia.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The end plate is segmented into distinct regions with different thicknesses (first region and second region). This segmentation allows the component to respond differently to thermal loads in different areas, with the thinner second region heating and cooling faster to reduce overall thermal cycling distortions.

Inventive Principle:

Principle #1Segmentation

2Stability of the object's composition

If end plates are made thicker to reduce deformation, then stiffness is improved, but distortion during thermal cycling increases due to mismatch with intermediate plates

Engineering Contradiction:

ImprovestiffnessVSAvoiddistortion

Core Design Contradiction:

Stability of the object's compositionVSShape

Solution Approach 1:

The end plates incorporate regions of different thicknesses to create local variations in stiffness. The thinner second region has lower stiffness that better matches the intermediate plates, reducing stiffness mismatch and thereby minimizing distortion during thermal cycling while the thicker first region maintains overall structural integrity.

Inventive Principle:

Principle #3Local quality

3Duration of action of moving object

If end plates are made thinner to reduce mass and thermal inertia, then thermal response time is improved, but structural strength decreases

Engineering Contradiction:

Improvethermal response timeVSAvoidstructural strength

Core Design Contradiction:

Duration of action of moving objectVSStrength

Solution Approach 1:

The end plates use non-uniform thickness distribution where the thinner second region provides fast thermal response while the thicker first region provides structural strength. This local quality variation allows the component to achieve both fast thermal response and adequate structural strength simultaneously.

Inventive Principle:

Principle #3Local quality

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 design extends the service life of the heat exchanger by reducing distortions and stress, while maintaining cost-effectiveness and reliability, and enhances heat transfer efficiency through turbulent flow.

Implementation Method 1

Heat exchangers are utilized in various technical applications for transferring heat from one fluid to another fluid. The cooling liquid or coolant takes up heat from the charge air and thereby cools the charge air.

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

Distortions within the heat exchanger occur because of thermal cycling and/or because of an inhomogeneous temperature distribution within the heat exchanger. The end plate having at least one expansion zone for reducing the stiffness thereof.

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS9243849B2Stacked plate heat exchanger with end plate expansion slots

Publication Date: 2016.01.26 MAHLE INT GMBH

AI summary

A heat exchanger has a plurality of intermediate plates arranged one atop the other to form a stack having first and second ends. At least one first fluid channel through conducts a first fluid and at least one second fluid channel through conducts a second fluid. The intermediate plates are geometrically configured to define at least a portion of each of the first and second fluid channels. An end plate is arranged on one of the ends of the stack and a first inlet opening communicates with the first fluid channel for introducing the first fluid and a first outlet opening communicates with the first fluid channel for conducting the first fluid out of the heat exchanger. A second inlet opening communicates with the second fluid channel for introducing the second fluid and a second outlet opening communicates with the second fluid channel for conducting the second fluid away from the heat exchanger. The end plate has at least one expansion zone for reducing the stiffness thereof.