Thermotec Engineering Services GmbH

Analysis of Vehicle Cooling Systems –

Approaches to Handle

System Complexity and

a Huge Number of Variants

Robert Tauscher

Overview

■ Introduction

■ Our daily business

■ System complexity and number of variants

■ Approaches to handle complexity and variants

■ Selected examples

■ Model generation level

■ HX-Subassembly

■ Engine model

■ Model calibration level

■ Steady state

■ Transient

■ Conclusion

Who is Thermotec?

■ an engineering company - 15 engineers and

.physicists - specialized on thermodynamics and

.fluid mechanics

■ automotive, aerospace and defense industries

■ simulation: thermal/hydraulic systems, thermal

.management and cooling .systems

(1D and 3D-CFD)

■ test benches: wind tunnel for radiator and heat

.exchanger performance tests

■ our customers:

www.thermotec-es.com

Our Daily Business

■ Analysis of vehicle cooling systems

■ Evaluation of concepts, variants, …

■ Dimensioning of components / complete systems

■ What if … analysis

■ Dimensioning / scaling

■ Pumps, fans (size, operating points, …)

■ Radiators (scaling)

■ Piping (pressure drop diameter, etc.)

■ Comparison of concepts / components …

■ Compare model with experimental data

■ Data pre-processing

■ Steady state and transient

■ Model calibration (experiment, 3D-CFD, …)

■ Evaluation / post-processing / documentation …

Vehicle Cooling System –

From a Simple Model to Complex Systems

and a Huge Number of Variants

Vehicle Cooling System –

From a Simple Model

The Challenge:

■ 1

■ 10

■ 40 – 50

■ 5.000 – 10.000

■ 25.000 – 100.000

■ 1 – 400 x 10 – 100

■ 15.000

Gamma‘s example of a simple

coolant System

(„coolant sytem 1D underhood“)

Facts & model data of a

state of the art

vehicle cooling system model

?

what is necessary and

how will the model look like,

that we can meet

the challenges?

Vehicle Cooling System – State of the Art Main Model Template

Visualization Evaluation

Coolant (HT)

Coolant (NT)

Hybrid-

Module

Driver Vehicle

Gearbox

Engine

Fan

Underhood

Air Flow

Aux. Comp.

el. Engine Air Con

Cond.

HX

HX

HX

HX

HX

HX

HX

HX

HX

HX

HX

HX

HX HX

HX

HX

HX

Tank Pump

Gear Driving Cycle Model Calibration

Air Calibration

Generator

Cabin

Wheel Transfer

Box Differential

Power Train

Clutch

Tire

ECU Thermal Management

Thermostat Oil

Thermostat Coolant Pump

Thermostat Coolant

Driving Strategy

Torque Converter

AC Circuit

Cabin

Eng. Cooling

Friction Eng. Oil C. Structure

Road

Environment

Oil Circuit

option: detailed models can be coupled

Gear Train

Vehicle Cooling System – Model Complexity and Variants

1

10

40 – 50

5.000 – 10.000

25.000 – 100.000

1 – 400 x 10 – 100

15.000

■ Universal GT-Main-Model(-Template)

■ Circuits: coolant (ht, lt,…), oil, air, refrigerant …

■ External subassemblies (placeholders) - main components of vehicle

■ Total number of parts in 1 model

■ Code lines in a „ready-to-simulate“ model file (*.dat-file)

■ Simulations/1night (variants x use cases)

■ Result files (400 variants with 10 use cases)

up to:

Approaches to Handle System Complexity and Number of Variants

■ Automated component-model setup consequently with modular blocks

■ 1 Subassembly for each component

■ Standard nomenclature and interfaces

■ Sub-assemblies can be exchanged easily

■ Optional more detailed models can be coupled

■ Components and main-model as templates

■ Model data provided from external files

■ Model creation via VBA (components, main-model, variants)

■ Automated pre- and post-processing – Excel / VBA

■ Pre-processing of component data and experimental data

■ Collection of results, data reduction

■ Standard reports, diagrams etc.

Examples for Automation

■ Automatic Component-model creation

■ Heat exchanger

■ Engine model

■ Model calibration steady state

■ Pre-processing of experimental data

■ Model calibration transient

■ Pre-processing of experimental data

■ System Identification

Automation – Component Generation: Heat Exchanger

Heat Exchanger

type

dimensions

hydraulic and thermal

performance

properties of matter

Heat Exchanger -

Process Relevant Data

manual step

Template

Data Sheet

automatic step

dimensions

properties of matter

efficiency

- hydraulic

- thermal

correction if necessary

Check

dimensions

height

# tubes

width

depth !

fins: spacing /

thickness

tubes: wall thickness

Scaling

(optional)

Visual Check & Last

Modifications

Generation of

GT-HX-Subassembly

and Automatic Pre-

processing

HX-test bench

Documentation of Nu-

Re-Regression Quality

correction of regression

to meet raw data (option)

add HX-Model to

Component Database

Engine

Automation – Component Generation: Engine–Model

type

variants

parameters

- approx. 100

performance maps

- approx. 50

Engine -

Process Relevant Data

manual step

Template

Data Sheets…

automatic step

.

Template

Performance Maps…

all parameter and data

sheets available?

parameter and data

consistent?

Check

Generation of GT-

engine Subassembly

Modular Internal Sub-

Assemblies

- heat rejection

- charge air

- coolant

- engine oil

- mechanics

- gas exchange cycle

- friction

- thermal mass /

structure

Hydraulic Calibration

(GEM3D, CFD…)

pressure drop water

jacket

Thermal Calibration

(System Identification)

heat rejection: road test

non-linear black-box mod.

0 500 1000 1500 2000 2500 3000 3500-5

-4

-3

-2

-1

0

1

2

3

4

5

6

7

Zeit [s]

T

KM

-Mota

us [

°C]

0 500 1000 1500 2000 2500 3000 35000

50

100

150

200

250

Zeit [s]

Geschw

indig

keit [

km

/h]

Versuch-GT (mod.)

Geschwindigkeit

Versuch-SYSID

add Engine-Model to

Component Database

Automation – Model Calibration

Goal:

■ find measurement errors / uncertainties and model calibration factors for

■ heat flow: heat rejection engine, air cond, gear box, …

■ flow rates: coolant, air, oil, atf, …

■ performance maps: heat exchangers, pumps, …

■ that the model can reproduce the measured temperatures

■ for all (sensor) positions

■ simultaneously and

■ for all use cases

■ as automated as possible

Automation – Model Calibration Steady State

Vehicle

Experiment

steady state

use cases:

wind tunnel

dynamo-

meter

test bench

Measurement errors vs.

CFD uncertainties used for model generation

temperatures

no feasible physical solution

flow rates

heat flow rates

perf. maps

Check &

Process co

nsis

ten

cy

no

me

ncla

ture

ma

tch

diffe

rentd

ata

so

urc

es

Pre-Process

Experimental Data

e.g. find steady state

temperatures when „not

steady state“

end of

experiment

steady

temperature

measured

coolant temp.

regression

Mod.

mo

de

l ge

ne

ratio

n

Cal.

loa

d, h

yd

rau

lic, u

nd

erh

ood flo

w

automatic optimization based

on maximum likelihood

simultaneous correction of

- flow rates

- heat flow rates

- performance maps (HX, …)

calibrated GT-Model

reproducing - in all probability -

correct temperatures at all

(measured) positions and for all

media flows (consistent solution)

Automation – Model Calibration Transient

calibrated GT-Model

reproducing

correct steady

temperatures at all

positions and

for all media flows

Model

Steady State

match GPS vehicle data

to road topology:

road grade, curvature

and

environment conditions:

temperature, pressure…

wind speed and wind

direction, …

Pre-Process

Experimental Data

thermal masses and

engine response, …

System Identification

e.g. Inertia

Google Earth &

GeoContext

global weather data:

wind speed and direction

Topology

.

Merged and Matched

Road & Vehicle Data

circuit segments

speed road grade

System Identification

Heat Rejection Engine

heat rejection @ road test

non-linear black-box or

grey box models

0 500 1000 1500 2000 2500 3000 3500-5

-4

-3

-2

-1

0

1

2

3

4

5

6

7

Zeit [s]

T

KM

-Mota

us [

°C]

0 500 1000 1500 2000 2500 3000 35000

50

100

150

200

250

Zeit [s]

Geschw

indig

keit [

km

/h]

Versuch-GT (mod.)

Geschwindigkeit

Versuch-SYSID

GT-Component

Generation

GT-Simulink Harness

for identified models

e.g.

thermal inertia

engine response

engine heat rejection

calibrated GT-Model

reproducing measured

temperature gradients

Model

Transient

96

98 9898 98

99 9998

97

9898 98

9898

98

92 92

93 93

95

97 96

9798

99

95

97 9798

97

9697 97

9898 98

99

90

102 102

101100

10099

98

96 96

95

97

99

98

95

91

98

99100

101

10099 99

102

99100

101

102

103

9999

98

100

100

90

95

100

105

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21

v.Fz

g [k

m/h

]

mittlere Geschwindigkeit/Runde v.Fzg [km/h] GDX F30N55RT

GDX F32B46RT

GDX F30B58RT

GDX F30B58RT

GDX F56B48JCW

Conclusion

■ What is necessary to handle and simulate complex cooling systems and

what is possible with Gamma Technologies GT-Suite?

■ Models / Simulation

■ Very short simulation times / fast covergence

■ Robust models

■ Modelling

■ Automation of model generation (VBA)

■ Component and system-model generation / modification

■ Co-simulation with System Identification / Simulink (SimulinkHarness)

■ Model data: administration in external file(s) or database (Excel)

■ Tools to model specified components very detailed

■ Simulation

■ Automation of pre- and post-processing (VBA, Excel)

■ Automation and organisation of simulation-runs 24/7 workload of server and

licenses (VBA, Excel)

■ Automation of model calibration (VBA and GT)

Thank You for Your Attention!

www.thermotec-es.com