Emission Standards EPA Heavy-Duty Engine · Cummins Confidential EURO-III, ... Cummins Confidential Driving EGR - Engine ... Provide data necessary to isolate and repair engine •

Cummins Confidential

0

5

10

15

20

1970 1975 1980 1985 1990 1995 2000 2005 2010Model Year

Oxi

des

of N

itrog

en (g

/bhp

-hr)

0.0

0.5

1.0

1.5

2.0Particulate M

atter (g/bhp-hr)PM

Steady StateTest

NOx + HC

Transient Test

NOx(Unregulated)

PM(Unregulated)

NOx

NOx + HC

NOx

PMUrban Bus PM

NOx + HC

(Proposed)NOx = 0.20PM = 0.01

EPA Heavy-Duty EngineEmission Standards


Medium-Duty Engines- ISB, ISC, Urban Bus Engines

Heavy-Duty Engines- ISL, ISM, N14, ISX, SIG-600

0

2

4

6

Jan ‘99 Oct ‘02

2.5g NOx+HC

4.0g NOx FTP

6.0g NOx EURO

Current Transient Test

EURO-III Steady-State Test

1998 1999 2000 2001 2002 2003 2004

2002 Product Development with Cooled EGR

0

2

4

6

Jan ‘99 Oct ‘02

2.5g NOx+HC

4.0g NOx FTP, EURO

6.0g NOx EURO-III

1998 1999 2000 2001 2002 2003 2004

Chrysler Pick-Up Engines

0

2

4

6

Oct ‘02

2.5g NOx+HC

4.0g NOx FTP, EURO

1998 1999 2000 2001 2002 2003 2004

Jul ‘99

Nov ‘99 Jan ‘04


EURO-III, and Not-to-Exceed

1000 1200 1400 1600 1800 20000

2000

Not-to-Exceed RegionEURO-III Steady-State Test Points

1500

1000

Engine Speed RPM

Torque ft-lb


Transient Not-to-Exceed

1000 1200 1400 1600 1800 20000

2000

1500

1000

Engine Speed RPM

Torque ft-lb

Time [sec]0.0 10.0

Engine Load [%]

0%

30%

100%

Random Test Points

1000 1200 1400 1600 18000

2000

1500

1000

Torque ft-lb FTP Transient Test



Emission Certification Test and Requirements

• Current Transient Test• EURO ESC 13 Mode Steady-State Test• Not-To-Exceed Requirements• Transient Not-To-Exceed Requirements• In-Use Testing and Compliance• Full disclosure of AECDs (Auxiliary Emissions Control Devices)

Consent Decree emissions requirements apply over a broad range of ambientconditions and altitudes:

• ambient temperature 55 - 95 degF - full compliance with NTE - no correction factors• humidity 50 - 75 grains / lb of air - full compliance with NTE - no correction factors• altitude - full compliance up to at least 5500 feet


5400

Peak Flame Temperature (R)

3600 4500

Mea

sure

d fs

NO

x (g

/kg)

1

10

100

Engine NOx Control Basics

• NOx Emissions Are VerySensitive To FlameTemperature• Low Temperatures Required

to Achieve 2gm/Hp-hr

• Need To Reduce FlameTemperatures ~400°

• How Do We Cost EffectivelyControl Temperatures?

~8gmNOx/Hp-hr

~2gmNOx/Hp-hr


What Is EGR?

Recirculated Exhaust Gas (EGR)

Engine

Exhaust6<%/v O2<18

Fresh Air21%/v O2

Charge(EGR + AIR)c.18%/v O2

EGR Gives Us A Handy Way To Reduce• Oxygen Concentration• Flame Temperature• NOx Emissions


Have a FlameTemperature High

Enough to Control DryParticulate4000

4500

5000

5500

6000

0 10 20 30 40 50 60 70 80-10-20-30

Tem

pera

ture

[R]

Crank Angle [CA]

Have a FlameTemperature LowEnough to Control

NOx

The Challenge:Alter the Combustion Event


NOx / BSFC & NOx / Soot Trade-Offs

1.0 2.0 3.0 4.0 5.0 6.0

0.360

0.350

0.340

0.330

0.320

0.0

Fuel

Con

sum

ptio

n[l

b/B

HP

-hr]

EURO-III NOx [g/BHP-hr]

Soot

Loa

din

g[%

at

250

hrs

]

7.0

1.0

2.0

3.0

4.0

5.0

Retarded Timing,No EGR

Design Envelopeof Current HDHardware

RetardedTiming, No EGR

App

rox.

MP

G

7.26

7.05

6.84

6.64

6.46

10,000

50,000 App

rox.

Oil

Dra

in[m

iles]

NOx Control with Cooled EGR


NOX Reduction Mechanisms

1.0 2.0 3.0 4.0 5.0 6.0

0.360

0.350

0.340

0.330

0.320

0.0

Fuel

Con

sum

ptio

n[l

b/B

HP

-hr]

EURO-III NOx [g/BHP-hr]

Soot

Loa

din

g[%

at

250

hrs

]

7.0

1.0

2.0

3.0

4.0

5.0

Retarded Timing,No EGR

Fuel Consumption is based on EURO-3 weightings, M11 - percentage change based on 0.315 lb/BHP-hr at 7.0g NOx on EURO-3 cycleSoot loading based on VMS 500 mile Corporate Composite Route / Duty Cycle - EGR soot is extrapolated from available data

Design Envelopeof Current HDHardware

App

rox.

MP

G

7.26

7.05

6.84

6.64

6.46

10,000

50,000

App

rox.

Oil

Dra

in[m

iles]

Cooled EGR

Cooled EGR requiredto achieve 2.5NOx+HC

Cooled EGRRetardedTiming, No EGR


0.0

0.2

0.4

0.6

0.8

1.0

.18 .19 .20 .21 .22 .23 .24

FS N

Ox

Rat

io(F

S N

Ox

/ FS

NO

x at

Zer

o EG

R)

Intake Charge Oxygen Mass Fraction

Effect of Inert / O2 Mass Fraction

.82 .81 .80 .79 .78 .77 .76Intake Charge Inert Mass Fraction

Ambient


0%

5%

10%

15%

20%

25%

30%

18 20 22 24 26 28 30 32

EGR Mass Fraction

Fresh Air:Fuel Ratio

70%, 20.1%

60%, 20.9%

50%, 21.5%

25%, 22.6%

NOx Reduction, %O2

NOx Control with Cooled EGR

100%

80%

60%

40%

20%

0%

16% 18% 20% 22% 24%

Oxygen Mass Fraction [%]

NOx Reduction from Non-EGR Case


Cylinder Pressure - Impact of EGR

0

500

1000

1500

2000

2500

3000

-90 -75 -60 -45 -30 -15 0 15 30 45 60 75 90

Crank Angle [degrees]

Cyl

inde

r P

ress

ure

[psi

]

Without EGR

With EGR

Constant Air Mass FlowConstant Power Output

8.3 L, 2200 rpm, 0 &11% EGR, 53 lb/min fresh air flow


Why so much heat?

Heat Rejection23%Exhaust Energy

33%

Work44%

Work44%

Exhaust Energy26%

Additional Heat Rejection

7%

Heat Rejection23%

With cooled EGR, we take some of the exhaust flow andreject that heat back to the coolant.


Mutually Dependent Design Targets


Mutually DependentDesign Elements

Base Engine• Peak Cylinder Pressure• Cylinder Liner & Ring Pack• Lube Oil Formulation

Fuel Injection System• Injection Pressure• Multiple Injections• Low Soot Combustion System

Air Handling System• Turbocharger• EGR System• Controls and Diagnostics

Vehicle Integration• Cooling System• Packaging• Engine Power Density


Description of an EGR System• Turbomachinery and assist devices for increasing

exhaust manifold pressure sufficiently above intakemanifold pressure to allow scheduling of charge massand EGR fraction

• EGR take-off, transport, and return to intake• EGR valve and actuator to regulate amount of

exhaust to be re-circulated• EGR cooler• Actuators, sensors, controls• Attachment hardware


EGR System Schematic

EGR Cooler

EGR Control Valve

) (

VGTurbocharger


System Sensors/Actuators

EGR Control Valve

) (

Compressor InletTemperature

EGR Valve Position

EGR DeltaP

IMT/IMP

VG/WG ControlValve

TurbochargerSpeed

EGR ReturnTemperature

ExhaustPressure

Barometric Pressure

) (


EGR Valve

EGR Exit(to cooler)

Gear Train

Motor


EGR Hardware - EGR Valve

• The EGR valve regulatesthe amount of exhaustgas that is recirculatedinto the intake system.


EGR Cooler

• Tube-and-shelldesign

• Stainless steel

• Engineered by• Behr…a leader• in heat• exchangers


800 1100 1400 1700 2000 23000

100

200

300

400

500

600

700

MD - Med Speed

HD

MD - High Speed

Speed (rpm)Speed (rpm)

Speed (rpm)Speed (rpm)To

rque

(ft-l

b)To

rque

(ft-l

b)

Torq

ue (f

t-lb)

Torq

ue (f

t-lb)

600 900 1200 1500 1800 2100200

400

600

800

1000

1200

1400

1600HD

600 900 1200 1500 1800 2100200400600800

1000120014001600180020002200

800 1200 1600 2000 2400 2800 32000

100

200

300

400

500

600

Exhaust-to-Intake Pressure Difference - Current Engines

Intake ManifoldPressure ExceedsExhaust ManifoldPressure

Exhaust ManifoldPressure ExceedsIntake ManifoldPressure


Driving EGR - Engine DeltaP

Speed (rpm)

Torq

ue (f

t-lb)

600 900 1200 1500 1800 2100200400600800

1000120014001600180020002200

Doesn’t Drive EGR!


Driving EGR - Engine DeltaPMD - High Speed

Speed (rpm)

Torq

ue (f

t-lb)

800 1200 1600 2000 2400 2800 32000

100

200

300

400

500

600

Drives too much EGR!


Wastegate Turbocharger with Pneumatic Actuation

Chapter 6 - 31

Turbine

Fresh Air

Boost

Wastegate

Exhaust Gas In

Compressor

Canister

Intake ManifoldPressure Sensing Line

Exhaust GasOut


Variable Geometry Turbocharger with Pneumatic Actuation

Fresh Air

Brake Air Pressure

CompressorTurbine

Nozzle Ring

Yoke MechanismShroud Plate

SpeedSensor


Illustration of VG Nozzle Ring and Restrictor Plate


ISX Compression Braking

0

100

200

300

400

500

600

1300 1500 1700 1900 2100

Engine Speed

Bra

king

Hor

sepo

wer

Current ISX Family 1

ISX for 2002 (400-500hp)


Control System Responsibilities

• Manage Engine Operation• Produce Torque

• Performance (fuel consumption, transient operation,throttle response)

• EGR on and off• Compensate for ambient condition variation, variability,

and system deterioration• Limit emissions output to legislated levels

• Meet FTP and SET requirements• Implement Approved AECD’s• Least Practicable• In Use compliance

• Optimize tradeoffs (fuel consumption, heat rejection,etc.) if hardware is capable


Control System Responsibilities ( cont.)

• Manage Subsystems• Fuel System (HPCR and HPI)• Charge Management (Several configurations)• Braking

• Provide Component Protection• New for 2002

• Condensation (Intake Manifold, EGR Cooler)• EGR Cooler Fouling• EGR Valve• Turbocharger

• Compressor Outlet Temperature• Speed• Turbine Inlet Temperature

• Manage emission compliance during protection


• Manage Sensor Inputs and ActuatorOutputs within ECM resourceconstraints

• Recognize and accommodatecomponent faults• Prevent operation outside of design limits while fault

condition present• Provide data necessary to isolate and repair engine

• Requires more ‘in range’ fault detection andaccommodation due to system complexity

• Meet legislated requirements (OBD II)

• Provide a system that can be calibratedin an expedient manner

Control System Responsibilities ( cont.)


Objective for Charge Handling Control

EGR Cooler

EGR Control Valve

VG TurbineCompressor

Charge Air Cooler

Create Conditions in IntakeManifold to supportCombustion Goals!


The Automotive Control Approach

• MEGR = Mcharge - Mair

• Use Speed-Density to calculatecharge mass

• Measure Mair using a sensor• But….., for high output diesels

• If EGR is roughly 20% and errors in massflows are about 5%

• Error in EGR rate estimation becomes awhopping 25% or so of calculated value!

• Obviously, this is unacceptable


Other Control Approaches

• Our approach to controls has evolvedover time

• Generally, the simplest control systemsrelate a measured parameter directly toan actuator output command• First Try

• Operate EGR valve On/Off• VG Position = f(Delta P across engine)

• Later• EGR valve modulation was added

• Our current controls approachsignificantly more sophisticated


Component Protection Functions

• The following componentprotection algorithms arenecessary in the controls• Compressor Outlet Temperature• Turbocharger Speed• EGR Cooler Condensation• Intake Manifold Condensation• Turbine Inlet Temperature• EGR Valve


Diagnostics and Fault Accommodation

• Sensor Out of Range Testing• Actuator short/open• Actuator Temperature• In Range fault detection and

accommodation - e.g.• EGR Valve Position• Intake Manifold Pressure (High/Low)• Charge Temperature• VG Actuation• EGR Cooler fouling


Non-Attainment Areas - OzoneOzone Nonattainment Areas


PM2.5 Non-Attainment AreasParticulate Nonattainment Areas


Diesel Oxidation Catalyst• Cummins and diesel industry have extensive

experience with this technology• Effective at removing unburned fuels and lube

(soluble organic fraction)• Compatible with higher level sulfur fuels• Maintenance free• Through flow design


• PM -- 20-50% Reduction• CO and HC -- >90%• Toxic HCs -- >70%

CarbonSoot

CatalystCatalystCatalystCatalyst

CarbonSoot

Diesel Oxidation Catalyst


Catalyzed Soot Filter


NOx Reduction Technologies

• Exhaust Gas Recirculation (EGR)• Selective Catalytic Reduction• Lean NOx Catalyst Technology• NOx Adsorber Technology


Exhaust StreamExhaust Stream

• Urea solution is added to exhaust with compressed air for atomization• Urea decomposes to ammonia and reduces NOx over catalyst

ECM Aqueous (32%)UREA Storage

Vessel

Exhaust Stream

SCR Aftertreatment

Compressed AirSupplyUREA

MeteringSystem

Sensors HydrolysisH2N-CO-NH3 > 2 NH3 + CO2

NOx Sensor forClosed-LoopControl, Diagnostics

Catalyst 4NO + 4NH3 + O2 > 4N2 + 6H2O8 NH3 + 6 NO2 > 7 N2 + 12 H2O

Oxidation Catalyst

Typical SCR System


NOx Storage Catalyst Operation


NOx Storage Catalyst Operation


NOx Adsorber / SCR Comparison

NOx Adsorber• >50% NOx conversion on light-

duty European cycle• Requires complex engine

calibration linked to catalystregeneration and desulfation

• 3-5% reduction in fueleconomy

• Ultra low sulfur fuel is required- sulfur traps probably required

• Complex, parallel systemrequired for HDD - exhaustswitching

• Additional PM control burdenduring NOx regen anddesulfation

• No secondary reductant needed

SCR• >60% NOx conversion on

European LD cycle; > 85% onEuropean and US heavy dutycycles

• Engine may be tuned forincreased fuel efficiency - EGRsynergy

• Ultra low sulfur fuel required• No high temperature

desulfation strategy required• No additional PM control

burden• On board storage of urea or

other NH3 source required

Documents

Emission Standards EPA Heavy-Duty Engine · Cummins Confidential EURO-III, ... Cummins Confidential Driving EGR - Engine ... Provide data necessary to isolate and repair engine •