GT CONFERENCEFRANKFURT, 17TH OCTOBER 2016

SIMULATING THERMAL MANAGEMENT SYSTEMS AND ENGINE HEAT DISTRIBUTION

Remy Fontaine

Senior CAE 1d CFD

AGENDA

1. Intro & Agenda

2. Motivation driving improvements in Thermal

Management

3. Overview and key principles of

advanced Thermal Management concepts

4. Opportunities for simulation

5. Modeling approaches & simulation use cases

6. Summary

2

Regulatory emissions (CO2, PM,..)

MOTIVATION DRIVINGIMPROVEMENTS IN THERMAL MANAGEMENT

Drive Quality & Performance

Passenger comfort

Customer requirements:Engine thermodynamics Engine & Transmission Friction

Cabin heatingStoichiometric operation

Customer requirements ...

3

& influencing effects

driven by Thermal Mngmt as, ...

(- 67K)

(- 9K) (+6%) (+4%)

Actively controlled coolant temperature

& flow rate setpoints.

Requires functionality of actuators:

Electrical coolant pump

Coolant control valves

Legend:

Heat source

Heat sink

Heat source/sink

Electrical actuator

ADVANCED THERMAL MANAGEMENT CONCEPT- OVERVIEW & KEY PRINCIPLES

Generated heat shall be ...

... retained or ...

... distributed to heat sinks.

4

OPPORTUNITIES FOR SIMULATION

Controls support:

Development & Validation support:

- Evaluate controls operating strategies

& diagnostics virtually

check quality of control e.g.

no overshooting of critical limits

- Provide boundary conditions

- Interpretation of test results (plausibility)

- Model training predictive capability

System development:

- Evaluate architectures & requirements

- Identify/mitigate system shortcomings

- Develop initial operating strategies

operating

strategy #1operating

strategy #1operating

strategy #1operating

strategy #1simulation

simulate

evaluate

mitigate

system

arch. #1

5

Calibration support:

- Frontload with initial calibration virtually

- ... for proliferation of propulsion system

MODELING APPROACHES & SIMULATION USE CASES

Modeling approaches

Model training data source:

- Top-down requirements, paper values, etc.

- Higher fidelity simulation, as 3dCFD, etc.

- Bottom-up status from test cell, flow bench etc.

Proliferation

System functionality

Overall system coverage Subsystem interaction

Physical fidelity

Hardware detail

Balancing of model development & computational effort with model capabilities.“Model approach as simple as possible as complicated as necessary.”

Variants of subsystem models required that are suitable for the use case.

System designSystem development

tasks as ...

, which require models

characterized by ...

CalibrationControl algorithmTest definition

etc.

etc.

On following slides 4 simulation use cases are given with balanced model approaches

6

System operation modes

MODELING APPROACHES & SIMULATION USE CASES

Ensure

feasibility of

electrical pump

and identify

improvement

potentials.

@ operation mode: maximum cooling

Identify optimal pressure drop

characteristics of serial/parallel paths

for required flow rates.

radiatorrequired coolant flow rate (contour) [l/min]

Simple, hydraulic isothermal

model to conduct sensitivity

studies using DOE simulations.

7

path A path B

path

C & D

Use case #1: Hydraulic coolant circuit analysis for system with electrical pump

Identify hydraulic power losses.

MODELING APPROACHES & SIMULATION USE CASES

high speed &

max. load

medium speed

& high load

outlet

inlet

Model required with high fidelity on

the engine gas-exchange, comb-

ustion & engine thermal side.

8

Use case #2: Engine operation analysis on engine coolant temperature & fuel type

MODELING APPROACHES & SIMULATION USE CASES

Use case #2: Engine operation analysis on engine coolant temperature & fuel type

high speed &

max. load

medium speed

& high load

component protection max.limit

stoichometric lambda

outlet

inlet

RON91:

critical temperature exceeded for

high power & partially for lower.

RON91:

High pwr.: increasing coolant

temperature requires increasing

enrichment

Lower pwr.: enrichment req´d at

increased coolant temperature

Model required with high fidelity on

the engine gas-exchange, comb-

ustion & engine thermal side.

9

MODELING APPROACHES & SIMULATION USE CASES

reqmn´tcabin heater air discharge temperature

time [s]

tem

pera

ture

[°

C]

Variation of control strategy for ...

coolant pump & valves

engine actuators

transmission ratio etc.

... to achieve cabin heating requirement

= minimal air temperature @ time.

Vehicle level simulation

Operating conditions critical

for cabin heating

Modeling approach focused

on computational speed

and sufficiently exact heat

rates.

10

Use case #3: Warm-up of propulsion system during cabin heating mode

= baseline

MODELING APPROACHES & SIMULATION USE CASES

Comprehensive vehicle system model

Closed loop control representation

Varying thermal mngmt operating strategy

Drive cycle:

11

Op. strategy #2:

Pump speed 0,

until critical

temperature

limit is reached.

Op. strategy #1:

Min. pump

speed held

constant.

Evaluation of

operation strategy 2) to 1):

save electrical power

retain heat in engine to

reduce friction

, ... while targeting wall

temperatures for

optimized combustion

Use case #4: Pump operating strategy during warm-up of propulsion system

= blue = green

= blue

= green

= green

= blue

SUMMARY

‘Simulating Thermal Management Systems and Engine Heat Distribution’

Advanced Thermal Management concept was

introduced giving the underlying motivation as well as

the opportunities for simulation in system hardware

development.

Simulation use cases were shown highlighting the

importance of balancing the modeling approaches, ...

• ... ranging from simple isothermal hydraulic models

for initial sizing of hardware to ...

• ... sophisticated vehicle models for investigating

control strategies.

“One size fits all” modeling approach does not work!

12

ACKNOWLEDGEMENTS

Jerry Hysko

Santhosh Akkaladevi

Asrar Chiya

Brezhnev Jeevanandam

Irina Dmitirieva

Rob McAlpine

Paul Mrozek

et al.

GM collegues:

Peter Stopp *

Matt Warner

et al.

Gamma Technologies:

13

Thank you for your attention!