Modeling a Phlegmatized Diesel-Engine in a Hybrid Electric Vehicle Using a Transient Predictive Model Michael Auerbach, October 25th, 2010, Frankfurt a. M.
Institut für Verbrennungsmotoren und Kraftfahrwesen Universität Stuttgart Michael Auerbach, Markus Ruf Prof. Dr.-Ing. Michael Bargende AUDI AG Pre-Development Diesel Engines Dr rer. nat. René van Doorn Dipl.-Ing. Immanuel Kutschera 2 Michael Auerbach, October 25th, 2010
Outline Motivation Introduction Phlegmatization Dynamic Simulation Engine Model Overview Injection Modeling Transient Simulation Summary & Outlook 3 Michael Auerbach, October 25th, 2010
Motivation Diesel vehicles: High market share (EU) Public opinion on emissions Conservation of ressources Reduction of fleet consumption Diesel Hybrid Electric Vehicle Main research aims for a P2-HEV-concept Fuel consumption Reduction of emissions Driveability 4 Michael Auerbach, October 25th, 2010
Introduction Phlegmatization General operating modes for Full-HEVs Electrical Driving Recuperation Load Shift of ICE Specific challenges for static Diesel-HEV emissions high values low values BSFC NO X torque torque 5 Michael Auerbach, October 25th, 2010 engine speed engine speed
Introduction Dynamic Effects on Emissions Effects on diesel engine emissions during dynamic load shift Inertia in air-system and control leads to miscalculation of cylinder state Decrease of load Lean zones in cylinder at high temperature Nitrous oxides Increase of load Rich zones in cylinder Soot High temperature NO X in remaining lean zones Reducing dynamic of the ICE in the HEV Phlegmatization of the Diesel Engine 6 Michael Auerbach, October 25th, 2010
Introduction Phlegmatization Simulated phlegmatized ICE-operation during driving cycle Electrical driving Upshift in ICE load Recuperation Downshift in ICE load torque [Nm] SOC [-] 240 200 160 120 80 40 0-40 -80-120 -160 80 70 0.40 60 0.39 50 0.38 40 0.37 30 0.36 20 0.35 10 0.34 500 510 520 530 540 550 560 570 0 580 time [s] 7 Michael Auerbach, October 25th, 2010 SOC v veh T ICE M EM velocity [km/h]
Introduction Transient Simulations Why transient Simulation? Mean-Value models are fast but hide numerous disadvantages Steady-state look up tables do not reflect realistic behavior of air path and heat up, therefore conditions for combustion may be incorrect Leaves the possibility to simulate emissions Delays in the air path and the control can be modeled Allows simulation of engine and exhaust aftertreatment warm-up Interaction with combustion model (wall heat transfer) and friction model Models of aftertreatment system can be added Inevitable for the simulation of effects on phlegmatization 8 Michael Auerbach, October 25th, 2010
Engine Model Overview Requirements for a transient diesel engine model Various (fast) sub-models and appropriate controls Model scheme Injection Model for transient simulations Soft - ECU EGR VNG Injection Aftertreatment Model Engine Model* Thermal Model * 1D-Simulation and Combustion 9 Michael Auerbach, October 25th, 2010
Engine Model Injection Measurements for each operating point (OP) High experimental effort Limited ability to simulate transient load/speed shifts Good and fast results at discrete OP s Physical incompressible flow model High modeling effort Lot of data needed (geometries, coefficients, fluid properties, ) High calculation effort though high access to physical processes Empirical model Reasonable experimental effort Experimental data adequate for parameterization Accurate results combined with acceptable computational effort 10 Michael Auerbach, October 25th, 2010
Engine Model Injection Measurements Preprocessing Model Generating Integration Fingerprint measurements Gradually incrementing injection duration at constant rail pressure level Repeating measurement for various rail pressure levels injector potential [V] 160 140 120 100 80 60 40 20 0-20 200 µs @ 1600 bar 500 µs @ 1600 bar 800 µs @ 1600 bar 1100 µs @ 1600 bar injection rate [mg/s] [mgs] 11 Michael Auerbach, October 25th, 2010 40 35 30 25 20 15 10 5 0-5 -0.0005 0.0000 0.0005 0.0010 0.0015 0.0020 0.0025 0.0030 0.0035 time [s]
Engine Model Injection Measurements Preprocessing Model Generating Integration Data preprocessing Extending gradient of rising and falling edge Defining start of injection (SOI) and end of injection (EOI) 40 35 injection rate [mg/ms] 30 25 20 15 10 5 0-5 -0.0005 0.0000 0.0005 0.0010 0.0015 0.0020 0.0025 0.0030 0.0035 SOI time [s] EOI 12 Michael Auerbach, October 25th, 2010
Engine Model Injection Measurements Preprocessing Model Generating Integration Data preprocessing Extending gradient of rising and falling edge Defining start of injection (SOI) and end of injection (EOI) Saving profiles to database 40 35 injection rate [mg/ms] 30 25 20 15 10 5 0-5 -0.0005 0.0000 0.0005 0.0010 0.0015 0.0020 0.0025 0.0030 0.0035 time [s] 13 Michael Auerbach, October 25th, 2010
Engine Model Injection Measurements Preprocessing Model Generating Integration Using RLTDependenceProfXYZ Used RLTs are rail pressure and injector activation duration Profiles from database are processed as XYTables in a XYZMapOfTables rail pressure [bar] 2200 2000 1800 1600 1400 1200 1000 800 600 400 200 14 Michael Auerbach, October 25th, 2010 0 0 100 200 300 400 500 600 700 800 900 1000 1100 injection activation duration [ms]
Engine Model Injection Measurements Preprocessing Model Generating Integration Soft - ECU AD SOA SOI InjMultiProfileConn p Rail ID m Inj t Inj p drop dm Inj /dt Start of Injection Variable Profile Dependency Object RLTs (ID, p Inj ) Mass flow drop 15 Michael Auerbach, October 25th, 2010
Engine Model Injection Measurements Preprocessing Model Generating Integration From Soft ECU: Start of activation, activation duration, rail pressure Injection rate [mg/s] injection delay SOA(MI) SOI(PI2) SOI(PI1) SOI(MI) TDC time [s] Crank Angle [ CA] 16 Michael Auerbach, October 25th, 2010
Transient Simulation Results Validation: Load shift @ 2000 rpm Time-scale results 3.5 Engine model vs. Engine test bench Cuts at discrete time steps ( CA-based) Injector model vs. Injector test bench measurement simulation 0 5 10 15 20 25 30 time [s] 28 24 20 16 12 8 4 0 80 IMEP [bar] injection rate [mg/ CA] 3.0 2.5 2.0 1.5 1.0 0.5 70 60 50 40 30 20 10 injected mass [mg] 0.0-50 -30-10 10 30 crank angle [ CA] 17 Michael Auerbach, October 25th, 2010-50 -30-10 10 30 crank angle [ CA] 0
Summary & Outlook Diesel-HEV is important for future mobility Control-strategy must focus on emissions, fuel consumption and driveability Main effect on emissions is Phlegmatization Transient engine simulation is inevitable for surveys on this effect Fast injection model and control needed for transient simulations Approach to a phenomenological injection model was shown Outlook Coupling of further models (thermal, exhaust aftertreatment, ) Using model for pre-application and testing of Diesel-HEV-Strategy 18 Michael Auerbach, October 25th, 2010
Thank you for your attention! Acknowledgements Thanks for support and inspiration to Michael Grill (FKFS), Björn Lumpp (MAN) and Torsten Rausch (AUDI AG) 19 Michael Auerbach, October 25th, 2010