Reciprocating Internal Combustion Engines

(1)

Prof. Rolf D. Reitz, Engine Research Center,

University of Wisconsin-Madison

2012 Princeton-CEFRC

Summer Program on Combustion Course Length: 9 hrs

(Wed., Thur., Fri., June 27-29)

Hour 8

This material is not to be sold, reproduced or distributed without prior written permission of the owner, Rolf D. Reitz.

(2)

Short course outine:

Engine fundamentals and performance metrics, computer modeling supported by in-depth understanding of fundamental engine processes and detailed

experiments in engine design optimization.

Day 1 (Engine fundamentals)

Hour 1: IC Engine Review, 0, 1 and 3-D modeling Hour 2: Turbochargers, Engine Performance Metrics Hour 3: Chemical Kinetics, HCCI & SI Combustion Day 2 (Spray combustion modeling)

Hour 4: Atomization, Drop Breakup/Coalescence Hour 5: Drop Drag/Wall Impinge/Vaporization Hour 6: Heat transfer, NOx and Soot Emissions Day 3 (Applications)

Hour 7: Diesel combustion and SI knock modeling

Hour 8: Optimization and Low Temperature Combustion Hour 9: Automotive applications and the Future

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Overview of Optimization Techniques

Enumerative or exhaustive Calculus or gradient-based

“local” methods which search in the neighborhood of current design point

Random

“global” methods such as genetic algorithms (GA) which typically converge on a global optimum

Design of Experiments (DOE)

Two-level factorial designs (main and interaction effects)

Response surface methods (RSM) Statistical model building

Univariate (one-factor-at-a-time)

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Genetic Algorithms

“Individuals” are generated through random selection and a “population” is produced A model is used to evaluate the fitness of

each individual

The fittest individuals are allowed to

“reproduce”

A new “generation” is formed - “mutations”

are allowed through random changes

The fitness criteria thins out the population and the most fit solution is achieved over successive generations

Senecal & Reitz, SAE 2000-01-1890

(5)

Implementation of Algorithm



 _

 X_i_,max X_i_,min

2 1

Goldberg, 1989 Carrol, 1996 Senecal, 2000

Precision

Binary representation of parameters X - “genes”

10101101 01101 01001001 - “chromosome” gene string

X 1 X 2 X 3



Evaluate merit f (X) for each generation member - identify “fittest”

Binary tournament selection Bit-swapping “Cross-over”

10101101 0110101001001 01100100 1110110101011

10101101 1110110101011

Parent 1 Parent 2

01100100 0110101001001 Descendants

Bit-flipping

Random “mutation”

(6)

0.1 0.2 0.3

0.4 0.5

0.6 0.7 192

196 200 204 208

0.2 0.4

0.6 0.8

1.0

All Citizens Produced Pareto Citizens

GISFC[g/kW-hr]

Soot[g/kgf]

NOx [g /kgf]

0.5 1.5

2.5 3.5

4.5 0.6

0.7

0.8

0.9 0.15

0.2 0.25 0.3

bowl diameter swirl ratio

NOx[g/kgf]

0.16 0.18 0.2 0.22 0.24 0.26 0.28 0.3

Optimization Methodology

Multi-Objective Genetic Algorithm Nonparametric Regression Technique

Simultaneous optimization of many objectives [1]

No merit function required to drive search Pareto front offers more information than

a single optimum

Regression technique suitable for handling irregular and undesigned data sets (e.g., GA data) [2]

Utilizes otherwise discarded optimization data

Captures magnitude of effects AND the shape of their response

Coello Coello & Pulido , 2001

Liu, IJER 2006

(7)

Example Optimization - piston bowl design Parameters and Objectives

7 Geometry Parameters:

Pip height

Bowl diameter

of bowl bottom

4 curvature control points

Injector Spray Angle Optimize:

NOx Soot ISFC

Genzale, SAE 2007-01-0119.

Swirl Ratio

(8)

0.1 0.2

0.3 0.4

0.5 180

200 220 240 260 280 300

0.0 0.4

0.8 1.2

1.6 2.0 All Citizens

Pareto Citizens

GISFC[g/kW-hr]

Soot[/kgf]

NOx [g/kgf]

Pareto Front Designs

NOx Soot GISFC

↓5%

↓42%

↓6%

↓68%

↑77%

↑15%

↓57%

↑6%

↓0%

↓45%

↓30%

↓2%

NOx Soot GISFC swirl = 0.7

swirl = 1.4

swirl = 3.1

incre asing

swirl Bowl geometry or injection

targeting trends?

Genzale, SAE 2007-01-0119.

(9)

Regression – Used to Identify Dominant Design Parameters

0.5 1.5 2.5 3.5 4.5 0.60.65

0.70.75 0.80.85

0.9 0.2

0.4 0.6 0.8

swi rlrati o bowl dia

meter (%b ore)

soot[g/kgf]

50 55 60 65

70 75

8085 0

0.2 0.4 0.6 0.6

0.8 1 1.2 1.4

pipheight (%bowldepth) spray angle

soot[g/kgf]

50 55 60 65

70 75

80 85 0.5 1.5

2.5 3.5

4.5 0

0.5 1 1.5 2

swirlratio spray

angle

soot[g/kgf]

• 3 dominant design parameters identified:

Regression fits performed for each design on the Pareto front

1. Spray angle 2. Swirl ratio

3. Bowl diameter

Genzale, SAE 2007-01-0119.

(10)

Increased swirl ratio is predicted to enhance soot reduction near the optimal spray angle.

Increases soot emissions at narrow spray angles.

Response Surface Observations:

An optimal spray angle is predicted.

Increased swirl ratio is predicted to decrease soot at all bowl diameters.

50 55 60 65

70 75

80 85 0.5 1.5

2.5 3.5

4.5 0

0.5 1 1.5 2

s wirlrati o sprayangle

soot[g/kgf]

0.5 1.5 2.5 3.5 4.5 0.60.65

0.70.75 0.80.85

0.9 0.2

0.4 0.6 0.8

swi rlrati o bowl dia

meter (%b ore)

soot[g/kgf]

Regression – Used to Understand Parameter Effects

NOx Soot GISFC

↓45%

↓30%

↓2%

swirl = 3.1

Genzale, SAE 2007-01-0119.

(11)

Optimization of Low Temperature Combustion - LTC

Increased interest in new combustion regimes

HCCI, PCCI, MK - offers simultaneous reduction of NOx and soot

High CO, HC High loads Transients

Challenges

NOx

EGR

Soot

Klingbeil, SAE 2003-01-0341

(12)

6 bar IMEP

0 10 20 30 40 50 60

0 20 40 60 80 100

250

180 g/kW-hr

MISFIRE

190 g/kW-hr

PRF[-]

EGR Rate [%]

10 bar/deg.

5.6 bar/deg.

Combustion Optimization - Fuel and EGR Selection HCCI simulations used to choose

optimal EGR rate and PRF (isooctane/n-heptane) blend

At 6, 9, and 11 bar IMEP 1300 rev/min

As load is increased the minimum ISFC cannot be achieved with either neat diesel fuel of neat gasoline

Predicted contours are in good agreement with HCCI

experiments

⁰ ¹⁰ ²⁰ ³⁰ ⁴⁰ ⁵⁰ ⁶⁰

190 g/kW-hr 180 g/kW-hr

10 bar/deg.

170 190 210 230 240

Net ISFC [g/kW-hr]

9 bar IMEP

0 10 20 30 40 50 60

16 bar/deg.

230

220

180 MISFIRE

210

190 200

11 bar IMEP

EGR Rate [%]

PRF

Kokjohn, SAE 2009-01-2647

(13)

Desirable to use traditional diesel type injector

Large nozzle hole (250 μm)

Wide angle (145° included angle)

KIVA + Multi-Objective Genetic Algorithm (MOGA)

Fuel reactivity and EGR from HCCI investigation (9 bar IMEP)

Global PRF = 65 EGR rate = 50%

Five optimization parameters Minimize two objectives

Wall film amount PRF Inhomogeneity

Simulations run to 10 °BTDC

21 generations with a population size of 24

Inj. 1 Pressure 100 to 1500 bar Inj. 2 Pressure 100 to 1500 bar

SOI 1 IVC to (SOI2-20) ºATDC

SOI 2 -50 to -30 ºATDC

Fuel split 0 ~ 100 % Diesel Fuel

0 1 2 3 4 5 6 7 8

0.18 0.20 0.22 0.24 0.26 0.28 0.30

All Solutions Pareto Solutions

PRFInhomogeneity[-]

Wall Film [% of Total Fuel]

 



²



1

1 ncells

i i GLOBAL

i

PRF ncells

GLOBAL i

i

m PRF PRF NSD

PRF m





 



Results

Film (%) 0.45

PRF Inhomogeneity 0.19

Parameters

Inj. Pres. 1 (bar) 115 Inj. Pres. 2 (bar) 555 SOI1 (°ATDC) -67 SOI2 (°ATDC) -33 Fraction in first pulse 0.64

Charge preparation optimization

Premixed and Direct Injected fuel blending

Kokjohn, SAE 2009-01-2647 Kokjohn & Reitz ICLASS 2009

(14)

Direct injected diesel Port injected gasoline

-80 to -50 -45 to -30

Crank Angle (deg. ATDC) In je c ti o n S ig n a l

^Squish

Conditioning

Ignition Source

Gasoline

Optimized Reactivity Controlled Compression Ignition (RCCI)

Optimized fuel blending in-cylinder

Gasoline Diesel

Diesel

(15)

Heavy- and light-duty ERC experimental engines

Engine Heavy Duty Light Duty

Engine CAT SCOTE GM 1.9 L

Displ. (L/cyl) 2.44 0.477

Bore (cm) 13.72 8.2

Stroke (cm) 16.51 9.04

Squish (cm) 0.157 0.133

CR 16.1:1 15.2:1

Swirl ratio 0.7 2.2

IVC (°ATDC) -85 and -143 -132

EVO(°ATDC) 130 112

Injector type Common rail

Nozzle holes 6 8

Hole size (µm) 250 128

HD LD

Engine size scaling Staples, SAE

2009-01-1124

(16)

•

IMEP (bar) 9

Speed (rpm) 1300

EGR (%) 43

Equivalence ratio (-) 0.5

Intake Temp. (°C) 32

Intake pressure (bar) 1.74

Gasoline (% mass) 76 82 89

Diesel inject press. (bar) 800

SOI1 (°ATDC) -58

SOI2 (°ATDC) -37

Fract. diesel in 1^st pulse 0.62 IVC (ºBTDC)/Comp ratio 143/16

Computer modeling predictions confirmed

Combustion timing and Pressure Rise Rate control with diesel/gasoline ratio Effect of gasoline percentage

Hanson, SAE 2010-01-0864

-30 -20 -10 0 10 20 30

0 2 4 6 8 10 12

14 ^Experiment Simulation

Crank [ATDC]

Pressure[MPa]

0 200 400 600 800 1000 1200 1400

89%

Gasoline 76%

82%

89%

ApparentHeatReleaseRate[J/]

Neat Gasoline Neat

Diesel Fuel

Dual-fuel can be used to extend load limits of either pure diesel or gasoline

Experimental validation - HD Caterpillar SCOTE

(17)

4 6 8 10 12 14 16 45 48

51 54 57 0.00 0.01 0.02 0.03 0.0 0.1 0.2 0.3

Heavy-duty RCCI (gas/gas+3.5% 2-EHN, 1300 RPM) Heavy-duty RCCI (E-85/Diesel, 1300 RPM)

Heavy-duty RCCI (gas/diesel 1300 RPM)

GrossInd. Efficiency

Gross IMEP [bar]

Soot [g/kW-hr]

HD Target (~2010 Levels)

NOx [g/kW-hr]

HD Target (~2010 Levels)

RCCI – high efficiency, low emissions, fuel flexibility

Splitter, SAE 2010-01-2167; Hanson, SAE 2011-01-0361

Indicated efficiency of 58±1%

achieved with E85/diesel Emissions met in-cylinder,

without need for after-treatment Considerable fuel flexibility,

including ‘single’ fuel operation Diesel can be replaced with

<0.5% total cetane improver (2-EHN/DTBP) in gasoline - less additive than SCR DEF

(18)

Dual fuel RCCI combustion – controlled HCCI

Heat release occurs in 3 stages (SAE 2010-01-0345, 2012-01-0375) Cool flame reactions result from diesel (n-heptane) injection First energy release occurs where both fuels are mixed

Final energy release occurs where lower reactivity fuel is located Changing fuel ratios changes relative magnitudes of stages

Fueling ratio provides “next cycle” CA50 transient control

18

-20 -10 0 10 20

0 50 100 150 200

Crank [^oATDC]

AHRR[J/o ]

Primarly iso-octane n-heptane

+ entrained iso-octane

Iso-octane Burn PRF Burn

Cool Flame

Primarly n-heptane

80 90 100 110 120 130 140 150 160 170 55

60 65 70 75 80 85 90 95

Intake Temperature [^oC]

DeliveryRatio[%iso-octane]



 

CA50=2 ˚ATDC

RCCI

SOI = -50 ATDC

RCCI

Kokjohn, IJER 2011

(19)

Understanding RCCI Combustion Process

Location B with dummy plug installed

Location A with optics installed fiber to

FTIR

common rail injector

common rail fuel spray Location B

with dummy plug installed

Location A with optics installed fiber to

FTIR

common rail injector

common rail fuel spray

Port Fuel Injector Optical Cylinder Head

Splitter, SAE 2010-01-0345

(20)

Experimental in-cylinder FTIR measurements of combustion process at two locations

Spectra shows different fuel species at locations A and B, a result of the reactivity gradient

Fuel decomposition and combustion products form at a slower rate at location B, extending

combustion duration

-20 -15 -10 -5 0 5 10 15 20 0

2 4 6 8 10

Experiment Simulation

Crank [ATDC]

Pressure[MPa]

0 80 160 240 320 400

HeatReleaseRate[J/]

2300 2700 3100 3500 3900

Reactants

A

Wavelength (nm)

-11 deg ATDC Products

B

-20 -15 -10 -5 0 5 10 15 20 0

2 4 6 8 10

Crank [ATDC]

Pressure[MPa]

0 80 160 240 320 400

2300 2700 3100 3500 3900

Reactants

A

Wavelength (nm)

B

-20 -15 -10 -5 0 5 10 15 20 0

2 4 6 8 10

Crank [ATDC]

Pressure[MPa]

0 80 160 240 320 400

2300 2700 3100 3500 3900

Reactants

A

Wavelength (nm)

B

-20 -15 -10 -5 0 5 10 15 20 0

2 4 6 8 10

Crank [ATDC]

Pressure[MPa]

0 80 160 240 320 400

2300 2700 3100 3500 3900

Reactants

A

Wavelength (nm)

3 deg ATDC Products

B

-20 -15 -10 -5 0 5 10 15 20 0

2 4 6 8 10

Crank [ATDC]

Pressure[MPa]

0 80 160 240 320 400

2300 2700 3100 3500 3900

Reactants

A

Wavelength (nm)

16 deg ATDC Products

B

Location A Location B

Understanding RCCI Combustion Process

Splitter, SAE 2010-01-0345

(21)

RCCI optical experiments

RCCI experiments in Sandia heavy-duty optical engine

LED illumination through side windows to visualize sprays

Images recorded through both piston- crown and upper window

Crank-angle-resolved high-temperature chemiluminescence with high-speed CMOS camera

Short-wave pass filter to reject long- wavelength (green through IR) soot luminosity

Engine Cummins N-14

Bore x stroke 13.97 x 15.24 cm

Displacement 2.34 L

Geometric compression ratio 10.75

GDI Iso-octane

100 bar 7x150 micron

Common-rail n-heptane

600 bar 8x140 micron Inc. Ang. 152°

(22)

Load: 4.2 bar IMEP GDI SOI: -240°ATDC

Speed: 1200 rpm CR SOI: -57°/-37° ATDC

Intake Temperature: 90° C Equivalence ratio: 0.42

Intake Pressure: 1.1 bar abs. Iso-octane mass %: 64

Kokjohn, ILASS-2011

RCCI combustion luminosity imaging

(23)

Engine specifications

Three engines operating with different forms of LTC combustion

Case Diesel LTC¹ Ethanol PPCI² Dual-Fuel RCCI³

Engine Cummins N14 Scania D12 CAT 3401

Displacement (cm3) 2340 1966 2440

Stroke (mm) 152.4 154 165.1

Bore (mm) 139.7 127.5 137.2

Con. Rod (mm) 304.8 255 261

CR (-) 11.2 14.3:1 16.1

Swirl Ratio (-) 0.5 2.9 0.7

Number of nozzles 8 8 6

Nozzle hole size (μm) 196 180 250

1. Singh, CNF 2009

2. Manente, SAE 2010-01-0871 3. D. A. Splitter, THIESEL 2010

Comparison of dual fuel RCCI and single fuel LTC

Kokjohn, A&S 2011

(24)

Comparison with single fuel LTC

Diesel LTC

Single early injection at 22° BTDC 1600 bar injection pressure

Diluted intake (~60% EGR) Ethanol PPCI

Single early injection at 60° BTDC 1800 bar injection pressure

No EGR Dual-fuel RCCI

Port-fuel-injection of low reactivity fuel (gasoline or E85)

Direct-injection of diesel fuel Split early injections

(SOI1 = 58° BTDC and SOI2 = 37° BTDC) 800 bar injection pressure

Vapor Fuel

Liquid Fuel Vapor Fuel

Kokjohn, A&S 2011

(25)

Dual-fuel RCCI

Comparison of gasoline-diesel and E85- diesel dual-fuel RCCI combustion

For fixed combustion phasing, E85-diesel DF RCCI exhibits significantly reduced RoHR (and therefore peak PRR)

compared to gasoline-diesel RCCI

allows higher load operation

E85-diesel RCCI combustion has larger spread between most reactive (lowest

RON) and least reactive (highest RON) ⁰

2 4 6 8 10

12 E85 and

Diesel Fuel

E85 & Diesel - Experiment E85 & Diesel - Simulation Gasoline & Diesel - Experiment Gasoline & Diesel - Simulation

Pressure[MPa]

Gasoline and Diesel Fuel

-20 -15 -10 -5 0 5 10 15 20

0 100 200 300 400 500 600 700

Crank [ATDC]

AHRR[J/deg]

85 90 95 100 105

0.00 0.05 0.10 0.15 0.20 0.25 0.30

E85 &

Diesel Fuel Gasoline &

Diesel Fuel

E85 & Diesel Gasoline & Diesel

RON [-]

MassFraction[-] RON Distribution at -20ATDC

Kokjohn, A&S 2011

(26)

Evolution of key intermediates:

Reaction progress

E85-diesel RCCI combustion shows a staged consumption of more reactive diesel fuel and less reactive E85

Ethanol and gasoline are not consumed until diesel fuel transitions to second

stage ignition ^1E-5

1E-4 1E-3 0.01

OH CH2O

C2H5OH Ethanol PPCI

MoleFraction[-] 1E-5

1E-4 1E-3 0.01

OH CH2O

Diesel Diesel LTC

-3 -2 -1 0 1 2 3

1E-5 1E-4 1E-3 0.01

Fuel E85 & Diesel

iC8H18

Diesel C2H5OH

CH2O OH

Dual-Fuel RCCI

Time [ms ATDC]



2

second stage first stage combustion combustion

fuel  CH O  OH



Comparison between diesel LTC, ethanol PPCI, and RCCI

Kokjohn, A&S 2011

(27)

Comparison between diesel LTC, ethanol PPCI, and RCCI

Diesel LTC

Earliest combustion phasing and most rapid energy release rate

High reactivity of diesel fuel requires significant charge dilution to

maintain appropriate combustion phasing (12.7% Inlet O₂)

Ethanol PPCI

Low fuel reactivity and charge cooling results in delayed combustion

Sequential combustion from lean- high temperature regions to rich- cool regions results in extended combustion duration

Dual fuel RCCI

Combustion begins only slightly later than diesel LTC

Combustion duration is broad due to spatial gradient in fuel reactivity Allows highest load operation due to

gradual transition from first- to second-stage ignition

-3 -2 -1 0 1 2 3

0 50 100 150 200 250 300 350

Ethanol PPCI Dual-Fuel

RCCI

Diesel LTC Ethanol PPCI Dual-Fuel RCCI (E85 & Diesel)

Time [ms ATDC]

AHRR[%FuelEnergy/ms]

Diesel LTC

RCCI Engine Experiments Hanson SAE 2010-01-0864 Kokjohn IJER 2011

Kokjohn SAE 2011-01-0357 Kokjohn, A&S 2011

(28)

‘Single fuel’ RCCI

RCCI is inherently fuel flexible and is promising to control PCI combustion.

Can similar results be achieved with a single fuel and an additive?

Splitter et al. (SAE 2010-01-2167) demonstrated single fuel RCCI in a heavy-duty engine using gasoline + Di- tertiary-Butyl Peroxide (DTBP)

SAE 2010-01-2167

0 2 4 6 8 10

20 25 30 35 40

Additive Concentration [Vol %]

EstimatedCN

DTBP EHN

2-Ethylhexyl Nitrate (EHN) is another common cetane improver

◦Contains fuel-bound NO and LTC results have shown increased engine-out NOx (Ickes et al. Energy and Fuels 2009)

Concentrations from SAE 2010-01-2167

Kaddatz SAE 2012-01-1110

EPA 420-B-04-005 Extrapolated

(29)

Comparison of E10-EHN and Diesel Fuel

E10+EHN

SOIc = -11.25°

Pinj = 500 bar Diesel Fuel SOIc = -11.25°

Pinj = 500 bar SOIc = -9.25°

Pinj = 900 bar SOIc = -7.9°

Engine experiments performed on ERC GM 1.9L engine

Diesel fuel and splash blended E10-3%

EHN mixtures compared under conventional diesel conditions

(5.5 bar IMEP, 1900 rev/min)

– Diesel fuel injection parameters adjusted to reproduce combustion characteristics of E10+EHN blend

Ignition Differences

– Diesel fuel SOI must be retarded to match ign. (Consistent with lower CN)

Mixing Differences

– Diesel fuel injection pressure must be increased by 400 bar to reproduce

premixed burn SOIc = -11.5 Pinj = 500 bar

SOIc = -9.25 Pinj = 500 bar SOIc = -7.9 Pinj = 900 bar

Diesel Fuel

(30)

Diesel fuel and E10-EHN compared under conventional diesel conditions (5.5 bar IMEP, 1900 rev/min)

– Diesel fuel injection parameters adjusted to reproduce combustion characteristics of E10+EHN blend

For CDC operation, E10+EHN and diesel fuel show similar NOx and soot

CDC operation with matched AHRR

Comparison of E10-EHN and Diesel Fuel

EPA 2010

(31)

-30 -20 -10 0 10 20 30 0

20 40 60 80 100 120

-42 SOIC (degATDC) Gasoline-diesel (84%)

CA [degATDC]

Pressure[bar]

0 40 80 120 160 200 240

HeatReleaseRate[J/deg]

E10+EHN/E10 (69%)

Diesel/Gasoline and E10+EHN RCCI

PFI E10 and direct-injected E10+3% EHN compared to gasoline – diesel RCCI operation

Combustion characteristics of gasoline- diesel RCCI reproduced with E10 – E10+3%EHN

– Adjustment to PFI percentage required to account for differences in ignitability

Operating Conditions

DI Fuel E10+EHN Diesel

PFI Fuel E10 Gasoline

Net IMEP (bar) 5.5

Engine Speed (RPM) 1900

Premixed Fuel (% mass) 69 84 Common Rail

SOIc(°ATDC) -32 to -52

Injection Pressure (bar) 500 800

Intake Temperature (C) 65 Boost Pressure (bar) 1.3

Swirl Ratio 1.5

EGR (%) 0

(32)

Performance of E10 and E10+EHN RCCI

Parametric studies performed to optimize efficiency of single-fuel RCCI at 5.5 and 9 bar IMEP Using a split-injection strategy,

performance characteristics of single-fuel + additive RCCI are similar to those of dual-fuel RCCI Peak efficiency data for E10/E10+EHN

shows higher NOx emissions, but levels meet EPA mandates

Soot is very low for all cases

E10/E10+EHN E10/Diesel

(33)

Additive Consumption Estimate Additive Consumption Estimate

Light-duty drive cycle average is 55% PFI fuel (i.e., 45% additized fuel)

3% additive level  EHN volume is ~1.4%

of the total fuel volume Similar to DEF levels

Assuming 50 mpg and 10,000 mile oil change intervals, additive tank must be

~2.7 gallons ¹⁰⁰⁰ ¹⁵⁰⁰ ²⁰⁰⁰ ²⁵⁰⁰ ³⁰⁰⁰

0 2 4 6 8 10 12

Speed [rev/min]

IMEP g[bar]

4 2 3

5

1

SAE 2001-01-0151 Size shows relative weighting

Assumes 50 mpg and 10,000 mile oil change interval

(34)

Summary and Conclusions

CFD modeling can be integrated with efficient optimization techniques for improved engine design

New combustion strategies can be discovered using CFD-optimization

Reactivity Controlled Compression Ignition strategy explained and validated with engine experiments

Dual fuel and single-fuel (with additive) RCCI demonstrated to provide combustion control using optimized blending of port- and direct-injected fuels

RCCI offers high thermal efficiency and meets EPA NOx and soot emissions mandates in-cylinder, without the need for after-treatment