An Engine System Approach to Exhaust Waste Heat …...An Engine System Approach to Exhaust Waste...

Caterpillar Engine Research

An Engine System Approach to Exhaust Waste Heat Recovery

Principal Investigator: David J. Patterson DOE Contract: DE-PS26-04NT42099-02 Presenter: Richard W. Kruiswyk DOE Technology Manager: John Fairbanks Caterpillar Inc. NETL Program Manager: Ralph Nine 15 August 2007 DEER Conference

Note: This presentation does not contain any proprietary or confidential information.

� Program Objectives

� Technical Approach

� Accomplishments

� Packaging Concepts

� Summary and Conclusions

Caterpillar Confidential: XXXXXEngine Research

Program Objectives

� Recover energy lost in the exhaust processes of an internal combustion engine and utilize that energy toimprove engine thermal efficiency

� Improve engine efficiency with: � No increase in emissions

� No reduction in power density

� Compatibility with anticipated aftertreatment

� TARGET – Demonstrate 10% improvement in overallthermal efficiency (OTE)


Ambient

Stack

Engine C15

A/C

LP Comp

HP Comp

LP Turb

HP Turb

DPF

CGICooler

HP Turb

Technical Approach

Recover energy lost

in the exhaust

processes

Baseline Engine

Caterpillar Confidential: XXXXEngine Research

CGI

Brake Power

Ambient

Stack

Engine C15

A/C

LP Comp

HP Comp

LP Turb

HP Turb

DPF

CGI Cooler CGI

BrakePower

Ambient

Stack

Engine C15

A/C

LP Comp

HP Comp

LP Turb

HP Turb

DPF

CGICooler

HP Turb

0.00

50.00

100.00

150.00

200.00

250.00

Ava

ilabl

e E

nerg

y (k

w)

Technical Approach

CGI

Brake Power

A/C

Ambient CGI

BrakePower

~ 34% of Exhaust availability used

~8% (primarily ports)

~16% (throttling, turbines, DPF)

~ 34% exits stack

~8% CGI flow (dumped)

Need System Level Approach to Maximize Exhaust Recovery

Peak Torque ConditionEngine C15

HP Comp HP Turb

Stack

LP Comp LP Turb

StackDPF

EnergyCGI

Cooler

Destruction

Heat LossCGI Energy

LP Work

HP Work

From Cylinder Caterpillar Confidential: XXXXEngine Research

Ambient

Stack

Engine C15

A/C

LP Comp

HP Comp

LP Turb

HP Turb

DPF

CGICooler

HP Turb

turbines, DPF)

umped)

~8% (primarily ports)

~8% CGI flow (d

Technical Approach

0.00

50.00

100.00

150.00

200.00

250.00

Ava

ilabl

e E

nerg

y (k

w)

Heat Loss

HP Work

LP Work

CGI Energy

Stack Energy

Destruction

CGI

Brake Power

Ambient

Stack

Engine C15

A/C

LP Comp

HP Comp

LP Turb

HP Turb

DPF

CGI Cooler CGI

BrakePower

~ 34% of Exhaust availability used

~16% (throttling,

~ 34% exits stack

Recovery Method

Insulation

Bottoming Cycle

Bottoming Cycle

Turbomachinery Intercooling

Peak Torque Condition

From Cylinder Caterpillar Confidential: XXXXEngine Research

(0.5%) (0.5%) (1.3%)

High Eff.LP Turb

Compressors

ry)

ompound or Bottoming Cycleoc

Technical Approach Port Insul. PipingPoPort Insul.rt Insul. PipingPiping

(0.5%)(0.5%) IntercoolingIIntercoolingntercooling(0.5%)(0.5%) (1.(1 3%3 ). %)


High Eff. HP Turbine (2.0%)

ine (1.0%)

(0.7%)

Stack Recove (4.0%

* Turb

High Eff.HP Turbine(2.0

High Eff.

%)HP Turbine(2.0%)

High Eff. LP Turbine(1.0%)

ineHigh Eff.LP Turb(1.0%)Compressors

(0.7%)(0Compressors

.7%)

Stack Recovery (4.0%)

StSt

* Turbocompound or Bottoming Cycle

ack Recovery(4.0%)

ack Recovery(4.0%)

* Turbocompound or Bottoming Cycle

Baseline is ’07 C15 Series Turbocharged On-Highway Truck Engine

XXXX

Nozzled / Divided Turbine vs Production

0.680

0.700

0.720

0.740

0.760

0.780

0.55 0.6 0.65 0.7 0.75 0.8

Velocity Ratio, U/C

Turb

ine-

Mec

h Ef

ficie

ncy

(%)

RND Data

Prod.Data

0.680

0.700

0.720

0.740

0.760

0.780

Accomplishments HPT +2.0%

Target: + 2.0% overall thermal efficiency ¾ Translates to ~ +10% turbine stage efficiency

Radial / Nozzled / Divided (RND) Turbine � High efficiency radial turbine wheel � Divided housing for engine breathing / pumping � Nozzled inlet for incidence control, turbine efficiency

Caterpillar Confidential: XEngine Research

+5% Turbine Efficiency Demonstrated Nozzled / Divided Turbine vs Production

0.55 0.6 0.65 0.7 0.75 0.8

Velocity Ratio, U/C

Turb

ine-

Mec

h Ef

ficie

ncy

(%)

RND Data

Prod. Data

XXXX

HPT +2.0%

Target: + 2.0% overall thermal efficiency ¾ Translates to ~ +10% turbine stage efficiency

Accomplishments

Mixed Flow Turbine � High efficiency wheel designed for improved pulse utilization � Inclined volute for maximum stage efficiency � Ball Bearings for low mechanical losses

Hardware Procured, Testing Underway

Caterpillar Confidential: XEngine Research

Flow Kg/s

Research Compressor

Production Compressor

Flow kg/sFlow Kg/s

Research Compressor


Flow Kg/s

Target: + 0.7% overall thermal efficiency ¾ Translates to ~ +2.5% compressor stage efficiency

Accomplishments Comp. +0.7%

High Efficiency Radial Compressor � Highly backswept wheel � Low solidity vaned diffuser

0.850.80.855

0.80.0.88

0.750.70.755

0.70.0.77

0.650.60.655

0.60.0.66

0.550.50.555

+2.5-3% Compressor Efficiency Demonstrated

Research Compressor


Effic

ienc

y -%

EfEffic

ienc

y -%

ficie

ncy

-%

Caterpillar Confidential: XXXXEngine Research 0.2 0.25 0.3 0.35 0.4

-– 0.0.2 0.25 0.3 0.35 0.4

-2 0.25 0.3 0.35 0.4

-Flow – kg/s

Supp.+4.0%

AdvantagesTurbocompound � Known Technology

� ‘Easy’ to package

Rankine Cycle � Cycle Efficiency � Insensitive to BP � ORC - additional fluid

Brayton Cycle � No additional fluid � Cycle Efficiency � Insensitive to BP � Packaging � Lower cost (compared

to Rankine) Caterpillar Confidential: XXXXXEngine Research

Target: + 4.0% overall thermal efficiency

Accomplishments

Stack Recovery Methods

� Packaging / cost

Disadvantages � Sensitive to BP

Ambient

Stack

Engine C15

A/C

LP Comp

HP Comp

LP Turb

HP Turb

DPFHE

Turb CompHP Turb

DPF

Turb


CGI

Brake Power

AmbientStack

Ambient

Stack

Engine C15

A/C

LP Comp

HP Comp

LP Turb

HP Turb

DPF

CGI

BrakePower

HE

Turb Comp


AmbientAmbientStack

Accomplishments

Supp. +4.0%

Brayton

Cycle

Mechanical or electrical connection


Accomplishments

Supp. +4.0%

Brayton Cycle – Engine Simulation Results � Simulated over speed load range w/ Brayton + port insul + IC

LPT comp

pipi

ng

Brayton

Insu

l.

+4%

+1.3% +0.5%

IC � Assumptions: 85% Brayton compressor 85% Brayton TurbineHPT 90% Heat Exch. Effectiveness3% Heat Exch. ΔP/P93% transmission efficiency

+5.8% Target at Design Pt. Backpressure representative of NOx A/T

plus partially loaded DPF


1000

1500

2000

1000

1500

2000

Accomplishments Target: + 4.0% overall thermal efficiencySupp.

+4.0%


30030 000

25025 000 5.8%5.8% 6.2%6.2%

Simulated Thermal Efficiency Δ

Design Point: + ~6%Drive Cycle: + 4-5%

Engi

ne L

oad

Engi

ne L

oad

4.3%4.3% 5.3%5.3%

4.0%4.0% 4.4%4.4%

500500

00500 1000 1500 2000500 1000 1500 2000Engine SpeedEngine Speed



Accomplishments

Supp.+4.0%


� Assumptions: 85% Brayton compressor 85% Brayton turbine 90% Heat Exch. effectiveness

Simulated Thermal Efficiency Δ 3% Heat Exch. ΔP/P Design Point: + ~6% 93% transmission efficiency Drive Cycle: + 4-5%


System will work if component performance targets are met

Effic

ienc

y (t/

s) @

Diff

user

Exi

t


Accomplishments

Supp. +4.0%

Brayton Cycle Component Development 0.88� Compressor Wheel (85% target) 0.86 � Aero Design Complete 0.84

0.82

0.80

0.78

0.76

0.74

0.72 1.0 1.2 1.4 1.6 1.8 2.0 2.2

� Turbine Wheel (85% target) � Aero Design CompleteCaterpillar Confidential: XXXXXEngine Research

Prototype Compressor Measured Performance

1.0

1.5

2.0

2.5

3.0

3.5

4.0

0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 normalized flow

pres

sure

ratio

85%

83%

81%

Normalized Flow

Pres

sure

Rat

io

Measured Performance

27G Axial Turbine Predicted

2.4 2.6 2.8 3.0

PressRatio(t/s) @ Diffuser Exit Ef

ficie

ncy

Pressure Ratio

Predicted Performance


Accomplishments

Supp. +4.0%

Brayton Cycle Component Development � Heat Exchanger (targets: 90% effective, 3% ΔP/P)

5 � Current ACPS technology: ~2ft3

Volu

me

(ft^3

) 4

3

2

1

0 80 85 90 95

Effectiveness (%)

� Unique microchannel manufacturing technology: ~1ft3


Ongoing research to achieve further reductions

Packaging

Base EngineCaterpillar Confidential: XXXXXEngine Research


Remote Mounting

Packaging

Base Engine On-Engine, 1ft3 H.E. On-Engine, 0.5ft3 H.E.

Foil Bearings

Summary

� Program goals can be achieved

� Path defined to achieve engine thermal efficiency of +10% at design point, + ~7% over drive cycle. Capability confirmed via engine simulation.

� Key components have been designed, analyzed, procured, and tested; component efficiencies at or close to target levels demonstrated

� Heat exchanger technology development key to packaging of system in mobile applications

� Next Steps: On-engine demonstration of advanced turbocharger technologies and design / procurement / bench-testing of Brayton cycle components


Acknowledgements

Caterpillar Thanks:

Turbomachinery design consulting, component procurement and integration.

Turbomachinery design consulting and optimization.

Turbomachinery design consulting and optimization.


Acknowledgements

Caterpillar Thanks:

• Department of Energy • Gurpreet Singh • John Fairbanks

• DOE National Energy Technology Laboratory• Ralph Nine


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An Engine System Approach to Exhaust Waste Heat …...An Engine System Approach to Exhaust Waste...

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