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ARAMCO SERVICES COMPANY, ARAMCO RESEARCH CENTER · PDF file Aramco purchased a 2013MY Cummins ISX 15L 450hp engine as a research test bed Low NOx GCI Test Engine. 5 Confidential •Estimated

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Text of ARAMCO SERVICES COMPANY, ARAMCO RESEARCH CENTER · PDF file Aramco purchased a 2013MY Cummins...

  • System Level 1-D Analysis of an Air-System for a Heavy-Duty Gasoline

    Compression Ignition Engine

    *PRAVEEN KUMAR, YU ZHANG, MICHAEL TRAVER

    ARAMCO SERVICES COMPANY, ARAMCO RESEARCH CENTER–DETROIT

    JOHN P. WATSON

    BORGWARNER TURBO SYSTEMS

    GT CONFERENCE November 4-5, 2019 │ Plymouth, MI, USA

  • 2

    Confidential

     Motivation

     Experimental Baseline

     Methodology for GCI System development

     Air-System Configurations

     Results/Discussions

    Presentation Outline

  • 3

    Confidential

    Motivation Future Demand

    • Stringent criteria pollutants emissions regulations

    • Global economic growth drives increase in commercial demand

    ExxonMobil 2017 Outlook for Energy: A View to 2040

    Total cost of ownership pressures will make gasoline range fuels attractive

    Cummins Atlantic LLC

    On-road HD

  • 4

    Confidential

    E G

    R C

    o o

    ler

    IAT

    EGR Valve

    Exhaust

    Restriction

    Valve

    C A

    C

    Exhaust

    Intake

    Displacement Volume 14.9 L

    Number of Cylinders 6

    Bore 137 mm

    Stroke 169 mm

    Compression Ratio 18.9, variants at 17.3 & 15.7

    Diesel Fuel System 2500 bar common-rail

    Air System single-stage VGT

    high pressure cooled EGR loop

    charge air cooler

    Engine Ratings 450 hp @ 1800 rpm

    1750 lb-ft @ 1000 rpm

    • Modern heavy duty highway diesel engine that can be installed in all major truck brands – non-

    road variant also available

    Aramco purchased a 2013MY Cummins ISX 15L 450hp engine as a research test bed

    Low NOx GCI Test Engine

  • 5

    Confidential

    • Estimated energy distribution for the stock engine operation.

    • Stock engine-out NOx target ~ 3-4 g/kWh

    A well matched air-system managed the pumping losses within 1.5-4.5%.

    Baseline GT-Power simulated ULSD CR17.3 perfromance

  • 6

    Confidential

    Low NOx GCI System Targets & Methodology

    GT-Power 1-D engine model & 3-D CFD model close-coupling for system design analysis.

    RON80 CR16.5

    HP-EGR Out

    Temp (C)

    LP-EGR

    Out Temp (C)

    CAC Out

    Temp (C)

    Intake

    Man Temp (C)

    110-130 70-80 45-46 65-70

    RON80 CR16.5

    A100 B25 B50 B75 C100

    IntMan P

    (bar) 3.56 1.48 2.42 3.16 3.67

    EGR +Res

    (%) 36.8 43.2 43.6 39.4 37.7

    EO NOx

    (g/kWh) 1.5 1.0 1.0 1.5 1.5

    ULSD CR 17.3

    A100 B25 B50 B75 C100

    IntMan P

    (bar) 2.9 1.2 1.9 2.5 2.4

    EGR

    (%) 19.1 26.4 24.9 22.5 21.6

    EO NOx

    (g/kWh) 3.9 4.0 3.7 3.9 3.4

    Ref: *SAE 2018-01-0226

  • 7

    Confidential

    Low NOx GCI  Combustion Behavior Matching (IMT 65-70C)

    Reasonable matching of ICP and HRR profiles between 3-D and 1-D models.

  • 8

    Confidential

    Low NOx GCI  Multiple Air Path Configurations

    Multiple air system configurations evaluated.

  • 9

    Confidential

    Air Systems  Configuration I : 1-Stage VGT HPEGR

    RON80 CR16.5

    HP-EGR Out Temp (C)

    LP-EGR Out Temp (C)

    CAC Out Temp (C)

    Intake Man Temp (C)

    110-130 70-80 45-46 65-70

     1-Stage VGT Turbine.

    1. Simplistic solution.

    2. Three different compressor maps.

    3. Variable geometry turbine provide superior control

    features.

    (I) 1-Stage VGT, HP Loop EGR

    Same configuration as production engine.

  • 10

    Confidential

    High pumping losses

    1-Stage + HPEGR Stock Turbocharger

    Insufficient pressure ratio range for the stock turbine to deliver the desired boost.

    BCs not met

  • 11

    Confidential

    1-Stage + HPEGR BS1 w/ HPEGR

    The boosting system satisfactorily delivers the air-thermal BCs.

    Combined turbocharger efficiency ~55% through mid-high load operations except C100.

  • 12

    Confidential

    Air Systems  Configuration III : 1-Stage (WG) LPEGR

    (III) 1-Stage WG, LP Loop EGR

    EGR flow controlled by back-pressure valve (BPV).

    CAC

    Mixer

    HPC T WG

    LP-EGR

    BPV

    IAT

    RON80 CR16.5

    HP-EGR Out Temp (C)

    LP-EGR Out Temp (C)

    CAC Out Temp (C)

    Intake Man Temp (C)

    110-130 70-80 45-46 65-70

  • 13

    Confidential

    BS3 w/ LPEGR

    Combined turbocharger efficiency ~50-55%.

    Strictly LPEGR flow incurred much higher pumping losses.

    High pumping losses

  • 14

    Confidential

    Low Pressure EGR challenges (Test cell)

    1. Test cell capability allowed to target 70-80C. (Cooling Tower)

    2. On vehicle LPEGR either cooled by Air-Air, Coolant-Air or a separate circuit.

    A sensitivity study conducted to understand the impact of LPEGR cooler Out T impact on the production BW 1-Stage DLEGR turbocharger matching.

    (IV) 1-Stage, Dual Loop EGR

    In a hybrid EGR configuration, low pressure EGR may allow efficiency benefits with the

    turbine.

    Air Systems  Configuration IV : 1-Stage DLEGR

    RON80 CR16.5

    HP-EGR Out Temp

    (C)

    LP-EGR Out

    Temp (C)

    CAC Out

    Temp (C)

    Intake Man

    Temp (C)

    110-130 70-80 45-46 65-70

  • 15

    Confidential

    1-Stage DLEGR HP-Prop% Sweep

    A100

    B50

    B25

    C100

    Inflection point: Dependent on boundary conditions

    LP EGR portion assisted boosting system to meet the BCs targets.

    HP-Portion (%) HP-Portion (%) HP-Portion (%)HP-Portion (%)

  • 16

    Confidential

    BS4 w/ DLEGR

    Combined turbocharger efficiency surpassed ~60%.

    Brake efficiency closer to stock ULSD @ CR 17.3 operation.

    A100

    (HP-Prop 41%)

    B75

    (HP-Prop 60%)

    B50

    (HP-Prop 53%)

    C100

    (HP-Prop 98%)

    B25

    (HP-Prop 69%)

    Best pumping #s from a 1-Stage turbocharger

  • 17

    Confidential

    BS4 system with combined turbocharger efficiency ~60% using a DLEGR system displayed

    superior performance.

    Pumping Losses All 5 Configurations

  • 18

    Confidential

     GT-Power based 1-D and 3-D CFD coupled methodology for boosting system

    evaluations.

     1-Stage HPEGR Configuration

     Very high combined turbocharger efficiency desired for HPEGR only configurations.

     1-Stage LPEGR Configuration

     System incurred terribly high pumping losses due to the LPEGR configuration.

     1-Stage DLEGR Configuration

     With a waste-gated option and appropriate EGR split strategy, combined turbocharger

    efficiency stretched to 60%.

     Stock boost option performed with DLEGR reasonable.

    HD-GCI Conclusions

  • 19

    Confidential

    Acknowledgements

    • David Branyon, Staff Engineer, Powertrain Design, SwRI.

  • 20

    Confidential

    Thank you for your attention

    Praveen Kumar, Ph.D.

    Research Scientist – Commercial

    Transport Fuels Research

    Aramco Services Company

    Fuel Technology

    Aramco Research Center – Detroit

    Tel.: +1 (248) 896-3873

    Email:

    Praveen.Kumar@aramcoservices.com

    mailto:Praveen.Kumar@aramcoservices.com

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