Advanced Engine Thermal Management

Sudhi Uppuluri Principal Investigator,

CSEG, LLC

Computational Sciences Experts Group

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The Speaker

Sudhi Uppuluri, Principal Investigator Sudhi has over 14 years of experience in the simulation industry. He worked as a consulting engineer and sales manager at Flowmaster USA for 8 years where he worked on various advanced fluid system modeling in Automotive and Aerospace fields. He has various technical publications on related subjects in SAE and AIAA journals. He holds a Masters in Aerospace Engineering from the University of Illinois at Urbana-Champaign and a Certificate in Strategy and Innovation from the MIT Sloan School of business. Email: Sudhi.Uppuluri@cseg.us Full Profile on Linked in: Sudhindra Uppuluri

Topics

a) Engine thermal management challenges

b) Traditional cooling system – Key considerations

c) HEV, EV specific challenges

d) Bigger picture

e) Roadmap

Why is Engine Thermal Management important?

• Cold Engine = Bad Fuel Economy – Incomplete

combustion – Increased thermal

losses through the combustion chamber walls

– Increased friction losses with the increase of the lubricant oil viscosity.

Frictional losses reduce as engine warms up

Referemce: 2000-01-0299 Warm-Up of a D.I. Diesel Engine:

Experiment and Modeling L. Jarrier and J. C. Champoussin Ecole Centrale de LYON R.

Yu Renault D.R. D. Gentile University of Versailles

Challenges for Engine Thermal Management

Engines are getting smaller More components

need cooling

Not enough heat for satisfactory heater core performance. Cabin comfort is compromised!

Electric components (Battery, inverter etc.) need to be cooled Overheating and fires!

Tighter packaging!

Right size component.

Fuel economy sensitive to temperatures!

Challenges – Simulating Engine Thermal systems

Why Engine Thermal

Management Modeling is

hard!

Responsibility fragmented across the organization

Model is data

hungry

Data not readily

available Majority of

data is steady-

state

Experimental procedures are for validating designs, not

models

Requires expertise across

multiple subjects

Lets look at key considerations in modeling a

transient Engine Thermal model

Steady State Flow Model – Starting point

Fairly Straightforward – Based on Geometry and

component supplier data

Key issue #1: Model necessary thermal interactions between sub-

systems

Requires integration of all key thermal fluid systems –

Cooling, AC, Engine Oil, Transmission Oil, Front-End cooling pack

Key Issue #2: Get Heat additions correct

+Qcomb

+QFric

Combustion heat = Energy from Fuel &Air mixture – Exhaust Energy – Work (indicated Power)

Frictional heat = Indicated Power –Pumping Work

Key issue #2a: Get heat losses correct

Heat Loss to the ambient (Conduction + Natural convection + Forced convection)

Heat Loss to the Coolant

Heat Loss to the Oil

Heat absorbed by the mass

Where the heat goes during warm-up

SAE 2000-01-0299 Warm-Up of a D.I. Diesel Engine: Experiment and Modeling L. Jarrier and J. C. Champoussin Ecole Centrale de LYON R. Yu Renault D.R. D. Gentile University of Versailles

Key issue #3: Modeling Thermal inertia right

Thermal inertia option 1 – Capturing minimum number of masses to predict warm-up

Include the correct volume of fluid. (Thermal inertia of the fluid)

Cylinder head

Upper block

Lower block

Sump Engine Oil Circuit

Coolant Circuit

Key issue #3: Modeling Thermal inertia right

• Thermal inertia option 2 – Capturing every heat transfer path (more components = more data required)

Reference: SAE paper 910302, Kaplan and Heywood.

Key issue #3: Modeling Thermal inertia right

• Thermal inertia option 3 – Capturing every heat transfer path (more components = more data required)

Reference: SAE paper 960073, Bohac, Baker and Assanis.

Where the heat goes during warm-up

Reference: SAE paper 931153, Shayler et al.

Key Factors in warm-up

Thermal Inertia

Heat distribution and loss

Key Issue #5: Include a dynamic coolant Thermostat

• Include dynamic model – Lift vs temperature

(supplier data, left) – Test data (below) – Dynamic mechanical model

HEV, EV specific challenges

• Li-ion battery cooling is • more than just an

additional isolated • cooling task. It requires

• complex thermal management and

• careful analysis

• Reference: Behr Technical Press Day 2009; http://www.behr.de/internet/behrmm.nsf/lupgraphics/Behr_Thermomanagement_TPT09_E.pdf/$file/Behr_Thermomanagement_TPT09_E.pdf

HEV Additions – front-end cooling pack

• Reference: Behr Technical Press Day 2009; http://www.behr.de/internet/behrmm.nsf/lupgraphics/Behr_Thermomanagement_TPT09_E.pdf/$file/Behr_Thermomanagement_TPT09_E.pdf

Segmented heat exchanger analysis to enable higher fidelity cooling pack analysis

For 600s simulation, starting from 40degC:

standard model 0.4347 kg

with coldstart friction engine 0.4557 kg +4.8%

with coldstart friction transmission 0.4543 kg +4.5%

with coldstart friction engine & transm. 0.4799 kg +10.4%

Improving fuel economy

Accurate numerical model of Engine Thermal Management

Predictive fuel economy and Engine thermal model

Evaluate a wide array of solutions to improve fuel economy and added HEV cooling challenges

0 50 100 150 200 250 3000

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

t [s]

fue

l co

nsu

mp

tio

n [kg

/s]

standard modelwith coldstart friction enginewith coldstart friction transmissionwith coldstart friction eng&trans

Functionality

Valu

e

Thermo-Fluid System Analysis Roadmap

Ensure accurate system operation • Flow balancing to ensure all components have

adequate flow • Evaluate individual component performance

Troubleshoot and Optimize • Transient behavior of system providing insight

into delivering a robust design • Optimization of system variables

Collaborate • Provide trade-off across multiple systems (cooling,

Lubrication, AC, transmission, front-end cooling pack)

• Value-added partnership with customers and suppliers

Deliver • Fuel economy benefits with

effective thermal management strategy

• Predictive analytical capability reducing prototype costs

Analysis basics in place. Are we here?

Topics covered

a) Engine thermal management challenges

b) Traditional cooling system – Key considerations

c) HEV, EV specific challenges

d) Bigger picture

e) Roadmap

FURTHER DISCUSSION

Sudhi Uppuluri has over 14 years of experience in the simulation industry. He worked as a consulting engineer and sales manager at Flowmaster USA for 8 years .He has various technical publications on related subjects in SAE and AIAA journals. He holds a Masters in Aerospace Engineering from the University of Illinois at Urbana-Champaign and a Certificate in Strategy and Innovation from the MIT Sloan School of business. Contact: Sudhi Uppuluri Principal Investigator Sudhi.uppuluri@cseg.us (781) 640 2329 www.cseg.us