ic engine combustion research, development, and challenges · ic engine combustion research,...

Research and Advanced Engineering

1

IC Engine Combustion Research, Development, and Challenges

J. James Yi

Technical Leader and Manager

Combustion System R & D

Ford Motor Company

June 5, 2013


2

�Technology Drivers

�Ford’s Global Technology Migration Strategy

�Ford EcoBoost Combustion system Development

�Future Research Opportunities

�Summary

Outline


3

Aggressive CO2 fleet targets will require advanced technologies for a variety of P/T combinations and vehicle applications.

0

2000 2005 2010 2015 2020 2025 2030 2035Model Year

New

Fle

et

LD

V G

as

oli

ne

Eq

uiv

ale

nt

g C

O2

/ k

m

NA WRE450

NA: Metro-Highway test cycle

EU: NEDC test cycle

EU WRE450

U.S. CAFE / CO2 Standard

U.S. One National Standard

(35.5 mpg in 2016)

New Proposal(54.5 mpg in 2025)

EU Legislation

0

2000 2005 2010 2015 2020 2025 2030 2035Model Year

New

Fle

et

LD

V G

as

oli

ne

Eq

uiv

ale

nt

g C

O2

/ k

m

NA WRE450

NA: Metro-Highway test cycle

EU: NEDC test cycle

EU WRE450

U.S. CAFE / CO2 Standard

U.S. One National Standard

(35.5 mpg in 2016)

New Proposal(54.5 mpg in 2025)

EU LegislationEU Legislation

Future CO2 Requirements


4

Emissions Regulations

Along with more stringent Nox and UHC emissions standard, Particulate emissions standards are reaching a level that has an impact not only on diesel vehicles, but also gasoline vehicles.

Emissions Regulations

3

4

5

6

7

150

Stage V

200 250

NOx + HC (mg/km)

PM

(m

g\k

m)

Stage VIIForecast

*

T2B5

Stage VI *2

100

0

1

0 50

SULEV30

*Estimated from particle number


5

Ford believes that the IC engine will play a key role in transportation in the near and mid-term and will continue to develop technologies to further extend its potential.

Begin migration to advanced technology

Full implementation of known technology

Continue leverage of Hybrid technologies and deployment of alternative energy sources

�Significant number of vehicles with EcoBoost engines

�Flex Fuel Vehicles

�Increased hybrid applications

�Stop/Start systems (micro hybrids) introduced

�Dual clutch and 6 speed transmissions replace 4 & 5 speeds

�Electric power steering – begin global migration

�Increased unibody applications

�Introduction of additional small vehicles

�Battery management systems –begin global migration

�Aero improvements

�CNG/LPG Prep Engines available where select markets demand

• EcoBoost engines available in nearly all vehicles

• Vehicle capability to fully leverage available renewable fuels*

• Increased application of Stop/Start

• Increased use of Hybrid Technologies

• Introduction of PHEV and BEV

• Diesel use as market demands

�Electric power steering - High volume

�Six speed transmissions - High volume

• Weight reduction of 250 – 750 lbs

• Engine displacement reduction aligned with weight save

• Additional Aero improvements

• Continue improving efficiency of internal combustion engines

• Volume expansion of Hybrid and PHEV technologies

• Continued leverage of BEV

• Continue to develop fuel cells; implementation timing aligned with fuels and infrastructure

• Continued weight reduction actions via advanced materials

2007 2011 2020 2030

Global Technology Migration Strategy


623

All-New 6.7L Power Stroke® V8 Turbo Diesel

2011 Super Duty

In the near-term, Ford has been adopting an aggressive strategy for both gasoline and diesel engines to reduce fuel consumption in major markets.

EcoBoost3.5L V6 Gasoline Engine

TaurusSHO

Near-Term CO2 Reduction

Ford Fiesta1.6L I4 Duratorq Diesel Engine


7





�Summary

Outline


EcoBoost Principles – Best Brake Thermal Efficiency (BTE)

0 1000 2000 3000 4000 5000 6000

Speed (rpm)

BM

EP

(bar)

20

15

10

5

0

Baseline PFI NA

Peak Power

• Boosting expands the good BTE island

• Downsizing shifts it to area of higher utilization

GTDI Extends the High Efficiency

region as well as the torque curve

Peak Torque

FTP

• FTP Drive Cycle typically centered about the ~25% load point for NA engines.

• For a naturally aspirated engine best BTE is typically about 80% load.

• GTDI greatly expands the best BTE island.

• Downsizing will move the GTDI best BTE island to a useable range.

GTDI


Slide 9

Technical Challenge: DI vs. PFI

1. Cold start crank and run-up emissions are much more challenging in a DI

engine than PFI

2. Over entire speed and load operation map, mixing in a DI engine is much

more challenging than PFI.

3.5L V6 GTDI3.5L V6 PFI


Slide 10

Added Technical Challenge With Turbo DI

3. Turbo DI combustion system is more prone to knock due to higher power

density than naturally aspirated engines.

4. Turbocharging makes engine cold-start even more challenging because it

requires more heat to light off catalyst due to heat loss to the turbo

system.

CAT.

ENGINE

•Extra surface area /

thermal mass due to

turbocharger.

Heat Flux > 2x W/L

Heat Flux > x W/L


Optical Engine

Numerical Modeling

Dyno Testing

Optimized Design

Integrated Up-front Combustion System Optimization Methodology


Slide 12

Series - III

Injector Spray Pattern

Optimization

Optimized Injector

Series - I Series - II

Baseline Injector

1500rpm/5bar

0.0

0.5

1.0

1.5

270 280 290 300 310

SOI (deg. BTDC)

Sm

ok

e (

FS

N)

Baseline Injector Spray Pattern

Optimized Injector Spray Pattern

15o

1500rpm/5bar

0.0

0.5

1.0

1.5

270 280 290 300 310

SOI (deg. BTDC)

Sm

ok

e (

FS

N)



1500rpm/5bar

0.0

0.5

1.0

1.5

270 280 290 300 310

SOI (deg. BTDC)

Sm

ok

e (

FS

N)



15oS

moke (

FS

N)


Optimized Piston

•CA=760

Modeling

Prediction

Optical

Images

Mixture well-centered Mixture off-center

Piston Bowl Geometry Optimization

Baseline Piston

A/F

rich

lean

•CA=760

lean

Rich


Slide 14

Spray-Piston Interaction and Its Impact on Combustion Stability


Slide 15

Spray-Piston Interaction and Its Impact on Combustion Stability


Slide 16

Single Cylinder Optical /

Thermal

Design Optimization Multi Cylinder

•Multi-hole

Spray

•Intake

Port

50+

iterations

<10

iterations

<5

iterations

•Piston

System Development Methodology – Quality & Time


17





�Summary

Outline


COCOCOCO2222

NA 4VNA 4VNA 4VNA 4VDOHCDOHCDOHCDOHC

PFIPFIPFIPFI

Proven Proven Proven Proven capabilitycapabilitycapabilitycapability

VariableVariableVariableVariableCamCamCamCamTimingTimingTimingTiming

DIDIDIDIHomogeneousHomogeneousHomogeneousHomogeneous

(incl. CR)(incl. CR)(incl. CR)(incl. CR)

MultiMultiMultiMulti----stage Boostingstage Boostingstage Boostingstage Boosting

FullFullFullFull----range Cooled EGRrange Cooled EGRrange Cooled EGRrange Cooled EGRMax. lowMax. lowMax. lowMax. low----load efficiencyload efficiencyload efficiencyload efficiency

(Lean, HCCI,…)(Lean, HCCI,…)(Lean, HCCI,…)(Lean, HCCI,…)

EcoBoost –Future advancements

Naturally Aspirated pathNaturally Aspirated pathNaturally Aspirated pathNaturally Aspirated path

Under Under Under Under devel.devel.devel.devel.

Increased BMEPIncreased BMEPIncreased BMEPIncreased BMEPAdvanced BoostingAdvanced BoostingAdvanced BoostingAdvanced BoostingKnock mitigationKnock mitigationKnock mitigationKnock mitigation

Improved BTE:Improved BTE:Improved BTE:Improved BTE:---- Cooled EGR Cooled EGR Cooled EGR Cooled EGR

EcoBoost –Technology progression

TurbochargerTurbochargerTurbochargerTurbocharger& Downsizing& Downsizing& Downsizing& Downsizing(architecture)(architecture)(architecture)(architecture)

EcoBoost

EcoBoost – Future Technology Development

Future powertrain versions of EcoBoost will improve fuel economy and emissions capability.

TimeTimeTimeTime

Direct Injection+

Turbocharging+

Downsizing


19

• Advanced Gasoline Turbocharged Direct Injection Engine Development

• Joint project w/ Michigan Technological University (MTU)

• Demonstrate by modeling / analysis and with a full-scale vehicle the ability to achieve greater than 25% weighted fuel economy improvement with a gasoline engine / conventional automatic transmission, while meeting T2B2 emissions standard.

Department of Energy Funding Award

Development of advanced EcoBoost technologies will be a major focus.

Cooled EGR

RWFE

Enrichment Zone

BM

EP

Lean Combustion

Advanced

wide range

Boost

IEM T

C

Air

Filter

A/T

Mu

ffler

BFT

LP EGR

Valve

Throttle

EG

R

Co

ole

r

Intake Manifold

Cat

LP EGR Throttle

W

G

Integrated

CAC

CCC TWC(s)

Lean after treatment


20

Advanced Combustion Modes

3000

CO-HC

Soo

t-Pro

duct

ion

Soo

t-Pro

duct

ion

NO xProduction

600 1000 1400 1800 2200 26000

1

2

3

4

5

6

Temperature [K]

Equ

iva

len

ce

Ra

tio

Φ=

1/λ

Conv. Path

LTC Path.LTC Path.

HCCI PathHCCI Path

LTC / HCCI

High Efficiency

Low NOx

Low PM

Combustion noise control is critical, but often there is an efficiency-noise tradeoff

Co

mb

. N

ois

e

Fuel Consumption

LTC

Tradeoff


21

• Knock limits fuel consumption benefits

– Limits compression ratio

– Forces spark retard and, in the limit, forces enrichment (both limit downsizing potential)

• In the case of knocking condition, only a small portion of fast burn events are with knocking.

Knock Mitigation Via Reducing Cycle-Cycle Variation


Injection and Spray Atomization

-- Example of Flash Boiling

Winter-blend Gasoline, 1 msA DI Spray 12.5 cc/s @ 10 MPa)

20º C1 bar

100 bar

Fuel TemperatureAmbient Pressure

Fuel Pressure

90º C0.5 bar100 bar

1.5 ms PW ~ 14 mg


Soot Formation in DI Engines

23

Viewing Direction


24

SI Particulate Formation

FILM

c≡c

How much liquid fuel reaches the surface?

Is it evaporated by the time the flame passes?

How well do we know the rich zone characteristics?

Rich and Hot

φ > 2

T > 1800 K

•Mixing

Droplets

Film

Bulk Vapor

Near Liquid

•Atomization

•Volatility

•Atomization

•Volatility

•Spray Targeting

•Surface Temp.

Usually easy to avoid

Hard to eliminate

How much fuel actually sticks?

To model PM, we will need to accurately answer a number of open questions.

Unlike diesel engines,

gasoline particulate

formation is not driven by

mixing processes, but

surface wetting.

What is the role of fuel composition? What level of soot formation chemistry detail is appropriate to predict soot yield?


25

� The integrated upfront combustion system optimization

process (modeling, optical engine, dyno) is the key to

designing high quality combustion system with high

efficiency; It has been applied in all Ford recent IC

engine development.

� Further understanding of fundamental physics is the key to the advanced combustion system development

– Advanced combustion mode (lean, LTC, RCCI, EGR,…)

– Fuel Injection and spray atomization (flash boiling,…)

– Knock mitigation and Cyclic phenomena understanding and control

– Emissions especially soot emissions formation mechanism and mitigation gasoline engine particulates

– Noise tradeoffs and noise reduction in advanced combustion modes

Summary


Ford/ORNL Combustion

Variation Modeling

26

GOAL

• Most engine modeling provides an “average” cycle, neglecting variation. This work aims to develop an efficient high-performance computational strategy for modeling cyclic combustion variation and begin to understand the triggers for CCV that could be optimized.

Allocated 2 million processor-hours for

development and primary study.

SCOPE

• Adapt sampling algorithm to convert the sequential problem to a massively-parallel study that can utilize TITAN computer system capability.

– Simultaneously launch many CFD simulations with varying boundary

conditions.

– Use LES turbulence models and detailed-chemistry combustion within

CONVERGE to capture details of variation.


Synergy between DI and

Ethaneol Fuel

27

•Evaporative cooling benefit of ethanol is very important

•SAE 2012-01-1277

•Stein, et al.

•SAE 2013-01-1321

•Jung, et al.

1.9 compression ratio

increase for additional

10% splash-blended

ethanol

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