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In In - - Use, On Use, On - - Road Emissions Testing of Road Emissions Testing of Heavy Heavy - - Duty Diesel Vehicles : Challenges Duty Diesel Vehicles : Challenges and Opportunities and Opportunities Mridul Gautam Professor Department of Mechanical and Aerospace Engineering West Virginia University NATIONAL RESEARCH CENTER FOR ALTERNATIVE TRANSPORTATION FUELS, ENGINES AND EMISSIONS

OnUse, On--Road Emissions Testing of Road Emissions ......SwRI (Human and Ullman, 1992) • General Motors (Kelly and Groblicki, 1993) • Ford Motor Company, 1994 • U.S. Coast Guard,

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  • InIn--Use, OnUse, On--Road Emissions Testing of Road Emissions Testing of HeavyHeavy--Duty Diesel Vehicles : Challenges Duty Diesel Vehicles : Challenges

    and Opportunitiesand Opportunities

    Mridul GautamProfessor

    Department of Mechanical and Aerospace EngineeringWest Virginia University

    NATIONAL RESEARCH CENTER FOR ALTERNATIVE TRANSPORTATION FUELS, ENGINES AND EMISSIONS

  • MOBILE EMISSIONS MEASUREMENT SYSTEMMOBILE EMISSIONS MEASUREMENT SYSTEM

    Mack TruckMack Truck

  • Purpose Of InPurpose Of In--use Emissions Measurementsuse Emissions Measurements

    •COMPLIANCE•I/M•SCREENING•INVENTORY•TECHNOLOGY DEVELOPMENT AND/OR

    ASSESSMENT

  • West Virginia University, Morgantown,WV 26506

    Available ToolsAvailable Tools

    • Engine Test Cells (Engine Recalls)

    • Chassis Dynamometers

    •Fixed and Transportable Chassis Dynamometers

    • On-road, On-board Emission Measurement Systems

  • Testing An Urban Transit Bus(WVU Transportable Heavy-duty Vehicle Emissions Testing Laboratory)

  • Need For On-board Emissions Measurement Systems

    • Real-world, on-road emissions are very different from in-laboratory emissions

    • Engine certification cycles are not representative of in-use, on-road operation• Federal Test Procedure (FTP)• Urban Dynamometer Driving Schedule (UDDS)

    • FTP and UDDS were developed by studying traffic patterns in New York and Los Angeles during the 1970s

    • Traffic patterns have changed over the years.• Different chassis dynamometer cycles yield

    very different emissions results

  • Challenges to Measurement of Challenges to Measurement of OnOn--board, Onboard, On--road Diesel Emissionsroad Diesel Emissions

    • Torque (or percent load) broadcast• Instrumentation

    –Portability; Bulk • Obsession with brake-specific emissions

    –It is recognized that the FTP (brake-specific emissions) is essential

    –However, In-use fuel-specific emissions would eliminate majority of challenges associated with brake-specific emissions measurements

  • Prior Art in Portable InPrior Art in Portable In--field field MeasurementsMeasurements

    • Caterpillar (Englund, 1982)• SwRI (Human and Ullman, 1992)• General Motors (Kelly and Groblicki,

    1993)• Ford Motor Company, 1994• U.S. Coast Guard, 1997• Flemish Institute for Technology Research,

    VITO, (Since 1991; de Vlieger, 1997)West Virginia University,Morgantown,WV 26506

  • West Virginia University, Morgantown,WV 26506

    InIn--Use Emissions Work at WVUUse Emissions Work at WVURelated to Consent DecreesRelated to Consent Decrees

    • PHASE I: DEVELOPMENT OF A STATE-OF-THE-ART MOBILE EMISSIONS MEASUREMENT SYSTEM FOR ON-BOARD, IN-USE HEAVY-DUTY VEHICLE APPLICATIONS

    • PHASE II: DEVELOPMENT OF IN-USE EMISSIONS TESTING PROCEDURES, AND TEST ROUTES

    • PHASE III: CONDUCT EMISSIONS TESTING ON A VARIETY OF IN-SERVICE DIESEL ENGINES USING THE WVU MOBILE EMISSIONS MEASUREMENT SYSTEM (MEMS) TO CHARACTERIZE REAL-WORLD EMISSIONS FROM SUCH ENGINES

  • West Virginia University, Morgantown,WV 26506

    InIn--Use Emissions Work at WVUUse Emissions Work at WVURelated to Consent Decrees (…Cont’d)Related to Consent Decrees (…Cont’d)

    • PHASE IV: CONDUCT ON-ROAD COMPLIANCE MONITORING OF HEAVY-DUTY DIESEL VEHICLES USING THE MONITORING TECHNOLOGY, AND PREVIOUSLY DEFINED TESTING PROCEDURES (AND DRIVING ROUTES) DEVELOPED BY WVU, AND APPROVED BY THE US EPA.

  • Mobile Emissions Measurement System(MEMS)

    Exhaust Samplingand Conditioning

    FlowMeter

    EngineInterface

    AmbientSensors

    ExhaustConstituentsNOx & CO2

    Differential Pressure,Absolute Pressure,and Temperature

    Engine Speed,Vehicle Speed,

    & TorqueAmbient

    Temperature,Pressure,

    & Humidity

    GPS

    Vehicle Speed & Location

  • MEMS Sampling and Emissions Analysis System

  • Mobile Emissions Measurement SystemFlow

    AnnubarDifferential Pressure TransducerAbsolute Pressure TransducerThermocouples

    EmissionsSolid State NDIR for CO2Zirconium Oxide Sensor for NOxNO2 ConverterThermoelectric ChillerHeated Sampling System

    Engine PowerECU Protocol AdaptorSerial Interface to DAS

  • Mobile Emissions Measurement SystemGPS

    DifferentialSerial or Analog Interface to DAS

    Ambient SensorsAbsolute Pressure TransducerRelative HumidityThermocouple

    System IntegrationNational Instruments PXI-1025 Chassis; PC-104Serial Interface Card64 Analog ChannelsExpandable to 256+ Analog ChannelsVisual Basic Interface Environment

  • V-Cone®No straight pipe runs

    “Pre-conditions”the flow

    Accuracy to +/-0.5%

    Repeatability to 0.1%

    Low headloss

    Low maintenance

    No recalibration

  • V-Cone®

  • CO2 Mass Emission Rates UsingV-Cone® and Annubar®

    (DDC Series 60, MY2000)

    0

    5

    10

    15

    20

    25

    30

    35

    -50 50 150 250 350 450 550 650

    Time (sec)

    CO

    2 (g

    /sec

    )

    CO2-AnnubarCO2 VCone

  • 0.6

    0.7

    0.8

    0.9

    1.0

    5400 7200 9000 10800 12600

    time (s)

    norm

    aliz

    ed r

    espo

    nse

    R12 - 9.1 umref - 9.8 umR12 - 10.8 umSF6 - 10.6 um

    (offset for clarity)

    30 ppm60ppm

    100 ppm120 ppm

    pressure transient when SF6 valve opens

    ~3 ppm

    Solid State NDIR Sensor - Response to SF6

    The signal to noise ratio for these deflections indicates a sensitivity limit of ~3 ppm for SF6 when the system response time is 1 second. Averaging over 5-10 seconds should improve sensitivity to better than 1 ppm.

    0102030405060708090

    100

    8.5 9.0 9.5 10.0 10.5 11.0 11.5

    wavelength (um)

    Tran

    smis

    sion

    (%)

    T1 - 9.1 umT2 - 9.8 umT3 - 10.8 umT4 - 10.6 um

    SF6

    R12

    GB

    GD

    GA

    Source: Ion-Optics, Inc.

  • Percentage of NO2 Reported by Zirconia Sensor

    NO2 Concentration (ppm) before NOx

    Converter

    Percent of NO2 after Converter Reported

    by MEXA-120

    62 - 124 70 186 78 248 82 310 78 372 74 434 70 496 65 558 62 620 58

  • Effect of Sampling Lines on NOx Measurements

    DD60SeriesEngine

    FourierTransformInfraredSpectrometerAnalyzer

    A

    B

    C

    D

    Heated Stainless Steel Line

    Cold Teflon Line

    Heated Filter

    NOx Converter

    Dryer

  • 0

    50

    100

    150

    200

    250

    300

    0 200 400 600 800 1000 1200 1400 1600 1800

    Time (Seconds)

    NO

    2 (p

    pm)

    NO2 emissions-450F (ppm) NO2 emissions-400F (ppm) NO2 emissions-300F (ppm)NO2 measured with dryer (ppm) NO2 measured without dryer (ppm) NO2 baseline (250F)-dry (ppm)

    A. Heated line

    C. Heated line + Converter + Dryer + Teflon line

    B. Heated line + Converter + Dryer + Heated line

    D. Heated line + Converter + Teflon line

    Effect of Sampling Lines on NOx Measurements

  • Comparison of Concentrations Reported by the 955 NOx Analyzer with Wet and Dry

    Exhaust Samples from a Mack E7-400 Engine

    -200

    0

    200

    400

    600

    800

    1000

    1200

    1400

    1600

    0 200 400 600 800 1000 1200

    Time (s)

    Con

    cent

    ratio

    n (p

    pm)

    Lab NOx - no chillerLab NOx - with chiller

    Cycle Integrated Percent Difference with Chiller: =8.5%

  • NOX Index

    (Concentration of NOx) x (Exhaust flow rate) x MWNOx

    (Concentration of CO2) x (Exhaust flow rate) x (12.011+1.008*(H:C))

    grams of NOx / kg of Fuel

    •NOx concentration•CO2 concentration•Fuel H:C ratio

  • NH3Oxidation

    NOX Sensor

    NH3 Sensor

    NH3 deNOx

    Exhaust gas

    NOX= (A+B)/2

    NH3= (A-B)/2

    Output: B (ppm)

    B=a –b

    (Here, a>b)

    Output: A (ppm)

    A=a + b

    NOx= a (ppm)

    NH3=b (ppm)

    NOx/ NH3 Zirconia Sensor

    Kobayashi et al. (2001), Mitsubishi Heavy Industries, Ltd., Technical Review Vol. 38, No. 3, Oct. 2001

  • t (msec)

    I (m

    A)

    t (msec)

    T (K

    )

    λλλλ (µµµµm)

    Flux

    (a.u

    .)

    λλλλ (µµµµm)

    Flux

    (a.u

    .)

    λλλλ (µµµµm)

    Flux

    (a.u

    .)

    t (msec)

    T (K

    )Source driver

    Source temperature

    Source emission

    Optical efficiencyGas attenuation

    Dual wavelength source/detector

    Detector response

    Sensor-on-a-Chip

    Source: Ion-Optics, Inc.

  • Real-Time Particulate Mass MonitorMARI Model RPM 100®

    Sample Conditioning System and a Microbalance

    Model RPM 100

    Model RPM 100

    Model RPM 100

    Model RPM 100

    MARIMARIMARIMARI

    Dilution Ratios – 1:12 to 1:2000

  • Crystal Surfaces

  • Continuous TPM Measured with MARI MODEL RPM 100®

    TPM Trace vs. Power: FTP Cycle

    -1000

    -500

    0

    500

    1000

    1500

    2000

    2500

    3000

    3500

    4000

    4500

    0 200 400 600 800 1000 1200 1400

    Time(s)

    Con

    cent

    ratio

    n (u

    g/m

    3)

    -100

    -50

    0

    50

    100

    150

    200

    Pow

    er(h

    p)

  • TPM Trace over the Transient Portion (Sinusoidally Varying) of a Customized Engine Cycle

    1000

    1100

    1200

    1300

    1400

    1500

    1600

    1700

    1800

    1900

    2000

    700.00 710.00 720.00 730.00 740.00 750.00 760.00 770.00 780.00 790.00 800.000

    50

    100

    150

    200

    250

    conc 10 sec

    conc 2 secs

    Speed

    Torque

    Pow er

  • ECU Derived Engine Torque

    WVU Approach:

    Measure the no-load percent load through the speed domain at the curb and employ the lug curve obtained through laboratory testing or from manufacturer-supplied data. .

    .

    ( ) rpmrpmnoload

    rpm

    rpmnoload

    rpmrpm T

    ECUECUECUECUtT max

    max%

    % ∗

    −−=

    Function of: Lug CurveFriction Torque (Zero Fueling Curve or Zero

    Flywheel (Zero Output Shaft Load) Percent Load Curve

  • Shaft Torque and ECU Percent Load Variation for a Modern Electronically

    Controlled Engine

    0

    100

    200

    300

    400

    500

    600

    500 1000 1500 2000 2500 3000Engine Speed (rpm)

    Shaft

    Tor

    que (

    ft-lb)

    0

    20

    40

    60

    80

    100

    120

    ECU

    Perce

    nt Lo

    ad (%

    )

    T2

    P2

    T3

    T1

    P3

    P1

  • Error in the Inferred Torque Due to an Error in Measured Percent Load

    -10

    -8

    -6

    -4

    -2

    0

    2

    4

    6

    8

    10

    0 20 40 60 80 100

    Percent Load (%)

    Erro

    r in T

    orqu

    e Valu

    e (%

    )

    14% Idle Point-2% Deviation-1% Deviation0% Deviation1% Deviation2% Deviation

  • Error in the Inferred Torque Due to an Error in No-Load ECU Load Reading

    -10

    -8

    -6

    -4

    -2

    0

    2

    4

    6

    8

    10

    0 20 40 60 80 100

    Percent Load (%)

    Erro

    r in T

    orqu

    e Valu

    e (%

    )

    14% Idle Point-3% Deviation-2% Deviation-1% Deviation0% Deviation1% Deviation2% Deviation3% Deviation

  • Integrated 30 Second Brake Power Windows Between Laboratory and ECU Inferred Data for a

    Modern Diesel Engine Exercised Through the FTP Cycle (600 to 1000 Seconds)

    0.0

    0.5

    1.0

    1.5

    2.0

    2.5

    3.0

    3.5

    600 650 700 750 800 850 900 950 1000Time (s)

    Integ

    rated

    Pow

    er (b

    hp-h

    r)

    Manufacturer SuppliedLaboratory SuppliedLaboratory Measured

  • Integrated 30 Second Brake Power Windows Percent Difference Between Laboratory and ECU

    Inferred Data for a Modern Diesel Engine Exercised through the FTP Cycle

    -100

    -75

    -50

    -25

    0

    25

    50

    0 200 400 600 800 1000 1200

    Time (s)

    Powe

    r Diffe

    renc

    e (%

    )

    Manufacturer SuppliedLaboratory Supplied

  • West Virginia University, Morgantown,WV 26506

    TEST ENGINES

    • Mack E7-400• 12 L, 400 hp, 1460 ft-lb torque

    • Cummins ISM-370• 10.8 L, 370 hp, 1350 ft-lb torque

    • Navistar T444E• 7.3 L, 210 hp, 520 ft-lb torque

  • West Virginia University,Morgantown, WV 26506

    NOX MASS EMISSION RATES ON FTP – REAL WORLD AND LABORATORY:

    CUMMINS ISM 370

    0.0

    0.1

    0.2

    0.3

    0.4

    0.5

    0 200 400 600 800 1000 1200

    Time (s)

    NO

    x (g

    /s)

    Dilute LaboratoryRaw MEMS

  • COMPARISON OF BRAKE SPECIFIC EMISSIONS

    RESULTS FROM THE FTP TEST CELL AND MEMS

    -4.39%

    524.0

    548.0

    CO2(g/bhp-hr)

    -0.18%Percent Difference

    4.389MEMS

    4.397Laboratory

    NOx(g/bhp-hr)FTP Cycle

  • West Virginia University, Morgantown,WV 26506

    CHASSIS DYNAMOMETER TESTING

    • Steady state testing was performed

    • Vehicle speeds of 35, 45, and 55 mph

    • Errors• MEMS CO2 = -2.17%• MEMS MEXA-120 =

    -2.14%0

    10

    20

    30

    40

    50

    60

    0 200 400 600 800 1000 1200Time (s)

    CO

    2 (g/

    s)

    Lab Dilute CO2MEMS CO2

    Cycle Integrated Percent DifferenceMEMS = -2.18

  • West Virginia University, Morgantown,WV 26506

    ON-ROAD ROUTE DEVELOPMENT• Four routes were developed to operate a heavy-

    duty Class 8 tractor throughout representative ranges of speed and load• Morgantown Route

    • Urban and highway operation

    • Saltwell Route• Highway operation

    • Bruceton Mills Route• Highway operation (mountainous terrain)

    • Pittsburgh Route• Urban and highway operation

  • CONCLUSIONS• An on-board emissions measurement system is needed to

    measure brake specific emissions from vehicles during their in-use operation, since engine and chassis dynamometer cycles are not representative of real-world driving conditions.

    • MEMS utilizes state-of-the-art technology to report emissions measurements. • Horiba BE-140 NDIR HC, CO, CO2 analyzer; Horiba MEXA-120 NOx

    analyzer.• Horiba NOx converter, M&C Products thermoelectric chiller.

    • MEMS is capable of reporting brake-specific emissions of CO2to within 3% and NOx to within 5% over an FTP cycle.

    • WVU has developed routes have been developed to operate the engine of a heavy-duty vehicle through a wide range of speed and load combinations.

    • It is anticipated that over the next couple of years in-use emissions measurement tools will be more compact, accurate, precise, rugged, and easy to use.