Development of Enabling Technologies for High Efficiency ...

Engine Technologies

Development of Enabling Technologies for High Efficiency, Low Emissions Homogeneous Charge Compression Ignition (HCCI) Engines

Program Manager: David Milam Caterpillar ®

DOE Contract DE-FC26-05NT42412 DOE Technology Development Manager: Roland Gravel NETL Project Manager: Ralph Nine

DOE Merit Review Washington, D.C. February 26, 2008

This presentation does not contain any proprietary or confidential information

CAT, CATERPILLAR, their respective logos, “Caterpillar Yellow” and the POWER EDGE trade dress, as well as corporate and product identity used herein, are trademarks of Caterpillar and may not be used without permission.

Outline

� Purpose of Work � Previous Reviewer Comments � Barriers � Approach � Performance Measures and Accomplishments � Technology Transfer / Collaborations � Publications/Patents � Plans for Next Fiscal Year � Summary

Caterpillar Confidential: XXXXXEngine Technologies

Caterpillar Non-Confidential

HECC Program

Integrated

Purpose of Work

� Develop technologies to enable a low emissions, high efficiency, production viable, low-temperature combustion engine system

Ther

mal

Effi

cien

cy (%

)

60

55

50

45

40

35

DOE Goal: 55% Thermal Efficiency

EWHR Program Technologies

HTCD Demo (w/NOx A/T)

MY 2007 Production

Goal �10% improvement in brake thermal efficiency �2010 on-highway/Tier 4 off-road emissions �w/o NOx aftertreatment �Maximize EWHR opportunity �Improved customer value

2006 2010 2013



10% Thermal Efficiency Improvement

46%

2007 baseline

Penalty with increased EGR, low Nox combustion (MY ‘07 technologies) Increased cylinder

pressure limit

Optimized combustion

Improved air system efficiency

Optimized cooling

Reduced parasitic losses

Bra

ke T

herm

al E

ffic

ien

cy

Why Low Temperature Combustion? – Potentially short combustion durations are thermodynamically attractive – Low NOx and PM emissions reduce or eliminate need for aftertreatment ÆReduced backpressure and lower cost ÆReduced regeneration cost



High Efficiency Combustion Minimize combustion duration Optimize combustion phasing High equivalence ratio combustion

Clean Combustion Low NOx emissions Minimize soot emissions

Previous Reviewer Comments

� “… insufficient discussion on meeting thermal efficiency targets.” – Path to 10% improvement in thermal efficiency was presented earlier in

this presentation.

� “… nothing was shown on how simulation is used to help direct investigations.” – Engine simulation was key to identifying the path to 10% thermal

efficiency improvement.



Potential Technology Solutions

High-Efficiency, Clean Combustion Barriers

Gap Analysis• Evaluate Production readiness • Evaluate customer value • Evaluate competing technologies

Technology Development

Production Viable

Solution

Technology Gaps

Potential Technology Solutions

� Mixture Preparation / Air Utilization – Excessive HC,CO and soot emissions with HCCI –

type combustion – Excessive soot at high BMEP (Ø > 0.8)

� High heat rejection – Increased EGR requirements – Increased in-cylinder heat transfer with HCCI

� Power density / load capability – Cylinder pressure and rise rate limits – High equivalence ratio at high BMEP

� Robust combustion control – Transient control of HCCI – Combustion feedback sensors – Combustion mode switching



Systems approach to high-efficiency, clean combustion development



�Develop advanced technologies to enable high thermal efficiency

�Develop a fundamental understanding of combustion processes

�Collaborate with technology experts

.

. . .

.

2.0 3 MPa/CAD

17 MPa 50 % 26 g/hp hr 1.4 g/hp hr 0.2 g/hp hr 0.1 FSN

-29.5°

-39.5°

-49.5°

-59.5° -64.5° -69.5°

Optical Engine Testing with Sandia National Lab

35

ISEC = dP/dCA =

30 � Objective: 25

PCP = 20 EGR =

Ove

rlim

it [-]

– Understand emissions and other trade-offs for early,narrow-angle injection strategy

ISCO = -ISHC =

15

10� Approach: ISNOx =

5 Smoke = – Sweeps of 7 parameters: inj. timing, inj. pressure, equivalence ratio, EGR, intake temperature, load, and boost

0

– Applied overlimit function to quantify proximity to compliance with emissions & other targets Injection Timing

– Used spatially integrated natural luminosity (SINL) 2.0 200 2.0 10

as measure of radiative heat transfer from combustion chamber 8 160

1.5 1.5

ISN

Ox

[g/h

p-hr

]

ISH

C [g

/hp-

hr]

Smok

e [F

SN]

6 120

� Accomplishment: 1.0 1.0

– Excessive smoke is primary barrier, followed by HC, 4

CO, and NOx (90% efficient oxidation catalyst 0.5 0.5 2 40assumed)

– Emissions trends correlate well with peak SINL 0.0 0.0 0 0 0 2 4 6 0 2 4 6

Peak SINL [mW] Peak SINL [mW]



ISC

O [g

/hp-

hr]

80



Optical Engine Testing with Sandia National Lab

� Objective: – Understand why emissions are well- correlated

with peak SINL

� Approach: – Combine pressure-based analysis, SINL, spray

visualization, and natural luminosity (NL) Cylinder-wall window spray visualization images for SOIa= -69.5 aTDC imaging diagnostics

� Accomplishment: – Peak SINL occurs after end of significant heat

release– Spray visualization movies show liquid fuel Cylinder-wall window high speed NL images for SOIa= -69.5 aTDC

impingement in piston bowl – NL movies show that pool fires from impinged

fuel lead to high peak SINL– If pool fires ignite Æ higher smoke & NOx from

stoichiometric & rich regions– If pool fires don’t ignite Æ slowly evaporating

fuel film gives higher HC (& CO?) Piston window high speed NL images for SOIa= -69.5 aTDC

IVA

Limit

Single-Cylinder Engine Testing Design-Expert® Software RiseRate RiseRate 65Design Points

6.24585 0 0Minimum 0.419553 IVA Limit

60

� Objective: X1 = A: Phasing 22Lower BMEPX2 = B: EGR

55Quantify the fundamental relationships betweencontrol parameters and engine performance and

Higher BMEP–

EGR

(%)

1 Air-fuel 50 22 ratio limit

emissions 2

45 3 4

Æ Input to 0-d combustion model for enginesystem simulation and basis for model based

6 5

40 Rise Rate Limitcontrol 6

35 -10 -5 0 5 10 15Æ Define optimal combustion mode for improved

thermal efficiency Phasing (ATDC)

BMEP Design-Expert® SoftwareFuel Efficiency BSCO (g/hp-hr)Design-Expert® Software

BMEPBSCO 1065 Design Points� Approach:

Design Points (BMEP at fixed fueling)

BSCO 25.0969

614.106 2.53647

547.033– Extensive exploration of key control parameters Combustion Retard X1 = A: Phasing 22Generated response surfaces to key control 60 Minimum X1 = A: SOI

X2 = B: EGR

parameters 25– X2 = B: Phasing 5IVA Limit 25

Com

bust

ion

Ret

ard

B: P

hasi

ng 20 20

610 1555 15 10 10

5 322222222

� Accomplishments: EGR

(%)

50 22600

0

– Established the effect of key control parameters 45 590

580on engine operating limits 570 -5

40 Rise 5Rise Rate LimitRate Limit 10

-1035 -10 -5 0 5 10 15 -100 -90 -80 -70 -60 -50 -40 -30 -20 -10

Caterpillar Confidential: XXXXX Phasing (ATDC) A: SOI Engine Technologies


Fuel Property Investigationin collaboration with ExxonMobil

� Objective: – Tailor fuel properties to engine operating conditions

for low temp combustion – Establish impact of fuel properties on emissions with

low temperature combustion

� Approach: – Tested diesel and gasoline/diesel blend fuels with

varying derived cetane number – Overlimit function used to evaluate fuels

• Compare combined effect on engine emissions and performance measures

� Accomplishments: – Gasoline/diesel blending is a feasible method to vary

the ignition characteristics of the fuel – Improved engine emissions and performance with

gasoline/diesel blends



The Overlimit is a function defined in: Cheng, A.S., Upatnieks, A., Mueller, C.J., “Investigation of Fuel Effects on Dilute, Mixing-Controlled Combustion in an Optical Direct-Injection Diesel Engine,” Energy & Fuels 21: 1989-2002 (2007).

Thermal Efficiency Improvement

100

� Objective: 90 80

– Compare energy flow of HCCI engine and 2007 conventional 70

on-highway diesel engine 60

– Quantify heat rejection differences between HCCI and 50

conventional combustion 40

30

Effect of reduced burn duration

Conventional HCCI

Const V

Const P

Ther

mod

ynam

ic E

ffici

ency

(%)

– Identify opportunities to increase engine thermal efficiency byutilizing low temperature combustion

� Approach: – Detailed system wide and individual component wide

analysis of energy and availability flow – Engine system simulation to evaluate thermal efficiency

building blocks � Accomplishments:

– Completed energy flow analysis for a multi-cylinder engine running in HCCI mode

– Identified opportunities for reducing heat losses including incylinder heat rejection

– Identified opportunities for optimally recovering wasted energy



20 10 0

6 8 10 12 14 16 18 20 22 24 26 28 30 Compression Ratio

Energy Flow Distribution for HCCI Engine

Pumping

Friction

Brake power Exhaust energy

Incomplete combustion

Other heat loss Engine heat

loss

% of fuel energy

Collaborations - External

•Program coordination

•Test/Analysis

•Truck/Machine system integration and packaging

•Combustion

•Fuels effects

•Combustion Chemistry/modeling

•Optical diagnostics

•Fuel spray and combustion

•Fuels effects

University of Wisconsin

Engine Research Center

Lund University

AEC MOU

•Closed loop control

•Transient controls

•Vehicle calibration

•Sensors



Collaborations - Internal

Advanced Material

TechnologyWorld-Class

Engine Testing

Resources Æ Results ÆCycle System Technology TransferSimulation Code Development

Aftertreatment Fuel Systems



Air Systems

3-D Combustion Simulation Code

Development

Controls & Sensors

Technology

Publications, Presentations, Patents

� 2007 DEER Presentation, “Heavy Duty Low Temperature Combustion Development Activities at Caterpillar”, Chris Gehrke, Michael Radovanovic, Doug Frieden, Eric Schroeder, Parag Mehresh, David Milam, Glen Martin, Charles Mueller and Paul Bessonette

� August 2007 AEC/HCCI Working Group Meeting Presentation, “DOE High Efficiency Clean Combustion”, Glen Martin and Charles Mueller

� Patent Applications – 2006- 11/498,001 - “Strategy for extending the HCCI operating range using low

cetane number diesel fuel and cylinder deactivation

– 2006- 11/584,889 - “Mixed high and low pressure EGR in HCCI engine” – 2007- 11/657,940 - “Power balancing cylinders in HCCI engine” – 2007- 11/699,522 - “Ignition timing control with fast and slow control loops” – 2007- 11/699,523 - “Recipe for high load HCCI operation”



Activities for Next Fiscal Year

Refine strategy to achieve 55% thermal efficiency – Determine best utilization of HCCI and other low temperature combustion technologies – Integration of exhaust waste heat recovery technologies

Identify and develop technologies to improve mixture preparation – Investigate injection strategy, spray characteristics and fuel property effects on mixture preparation and combustion – Investigate air motion and stratification impact on mixture preparation and combustion

Increase load range and thermal efficiency – Investigation of diesel/gasoline fuel blending as a means to increase load range and thermal efficiency of HCCI – Investigate other low temperature combustion regimes for high BMEP operation

Identify and develop technologies to reduce heat losses – Investigate concepts to reduce in-cylinder heat transfer – Evaluate concepts to reduce/recover heat from EGR system



Summary

� Focused on achieving 10% improvement in thermal efficiency without NOx aftertreatment to meet 2010 on-highway / Tier 4 off-road emissions standards

� Combine understanding of low temperature combustion fundamentals with development of enabling technologies to deliver a production viable, high-efficiency, clean combustion engine.

� Technical Accomplishments – Identified liquid fuel impingement as a significant factor in engine emissions – Established relationship between key control parameters and engine operating limits – Gasoline/diesel blending is a feasible method to vary the ignition characteristics of the fuel – Completed energy audit of HCCI engine and compare to conventional diesel engine – Completed design changes to variable compression ratio engine to reduce parasitic losses

� Collaborations key to success – Sandia providing key insight into combustion through optical engine explorations – ExxonMobil collaboration leading to improved understanding of fuel property effects on HCCI

combustion – IAV collaboration providing advanced transient controls insight



Back-up Slides



Thermal Efficiency Improvement (cont.)

� Objective: – Establish thermal efficiency benefit of a variable compression

ratio (VCR) engine using diffusion combustion– Reduce parasitic losses associated with VCR engine

� Approach: – Compared performance of to production C15 to quantify

parasitic losses

– Conducted teardown inspection of engine

� Accomplishments: – Identified root causes of increased parasitic losses associated

with VCR mechanism

– Identified design changes to reduce parasitic losses by 5% VCR - US Patent

Application 2006/0112911



Development of Enabling Technologies for High Efficiency ...

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