2009,., July 6th 2009 Overview Simulation benefits in the framework of the powertrain development process Boundary conditions for powertrain development Challenges and requirements for incylinder CFD CAE organisation at BMW Powertrain The incylinder simulation workflow at BMW Powertrain Development Challenges and requirements in powertrain CFD CFD in the framework of the engine development and simulation process Examples Summary & Outlook of CFD applications in powertrain development at BMW Development and trends Summary Outlook
July 6th 2009 Customer Expectations and Legal Requirements. Dynamics performance, response, agility smoothness sound, sound comfort smoothness, weight reduction Customer Fuel Efficiency/ CO2 Legislation, Society Focus: worldwide Self Commitment ACEA 2008, ACEA 2012 Japan 2010 Tail Pipe Emissions Focus: USA / California LEV I o LEV II o ULEV II PZEV: SULEV/Zero Evap EU4 Æ EU5 Æ EU6 July 6th 2009 Comparison of Emissions Requirements for Diesel Engines. NOx 0.25 EU4 EU5 EU6 +PN PM [g/km] 0.025 [g/km] [g ] 0 18 0.18 0.08 0 08 0.05 0.005 0 0045 0.0045 0.5 EU4 Gasoline 1 CO [g/km] 0.09 HC [g/km] 0.1
July 6th 2009 Comparison of Emissions Requirements for Gasoline Engines. NOx EU4 PM [g/km] EU5 EU6 Diesel +PN PN EU6 +PN 0.005 0.0045 0.0045 [g/km] 0.08 0 06 0.06 0.011 0.006 (NMOG) 0.006 SULEV 0.068 NMHC HC [g/km] 0.1 0.09 0.59 1 CO [g/km] Diesel and gasoline emissions requirements are converging towards similar values Most stringent regulations in CARB states of the US Particulate number as additional restriction July 6th 2009 Development of the BMW EfficientDynamics Gasoline Engines. SULEV ULEV II ULEV BMW engines with VALVETRONIC -5% -10% -20% BMW engines with HPI BMW engines with VALVETRONIC BMW engines with BIVANOS HC, NOx, particulate emissions -15% CO2 emissions
Overview of EfficientDynamics CO 2 Measures. Powertrain Central DI in lean burn mode High Precision Injection Twin Turbo Variable Twin Turbo Engine Downsizing Gearbox efficiency Aerodynamics Air flow Through flow Active aerodynamics Road resistance Tyres with reduced rolling resistance Electrification Hybridisation Auto Start Stop Function Brake Energy Regeneration Electrical Assist Electrical driving Light weight design Requirement lightweight design Concept lightweight design Material lightweight design Manufacture lightweight design Heat management Selective Aggregate-Component cooling Fest heating Insulation Friction reduction Energy Gasoline Diesel Natural Gas Alternative Fuels GTL, BTL Hydrogen Additional components Demand oriented control Electr. water pump Electr. steering Climate compressor decoupling Electr. driving dynamics system y g g y y Outlook: Models with 140g/km and less. BMW EfficientDynamicsi i Minimalism * Data as of April 2009 27 BMW G d l b l 140 /k CO 27 BMW Group models below 140 g/km CO 2 about 40 % of the European BMW Group sales
Fuel Consumption BMW Group vs. ACEA. Competitor A Competitor B 65% of consumption reduction due to powertrain enhancements Engine Measures Energy Management Reduction Driving Losses Gearbox Drive Train Overview Simulation benefits in the framework of the powertrain development process Boundary conditions for powertrain development Challenges and requirements for incylinder CFD CAE organisation at BMW Powertrain The incylinder simulation workflow at BMW Powertrain Development Challenges and requirements in powertrain CFD CFD in the framework of the engine development and simulation process Examples Summary & Outlook of CFD applications in powertrain development at BMW Development and trends Summary Outlook
BMW EfficientDynamics. Driving pleasure Increased efficiency Reduced emissions BMW EfficientDynamics: Less Input More Output. More Power Less Weight Less Consumption and Emissions
Development of the BMW EfficientDynamics Gasoline Engines. thermodynamic efficiency Direct injection (DI) for homogenous + stratified mode DI ( >1) VALVETRONIC + DI ( =1) VALVETRONIC BIVANOS BMW Motoren mit VALVETRONIC 4/6/8-cylinder 12-cylinder Direct injection (DI) for homogenous operation mode 6-cylinder Port fuel injection (PFI) for homogenous operation mode Europa: CO 2 Emissionen technical complexity Applicability of the Stratified Lean Burning Mode. Stratified combustion system requires NOx adsorption catalyst as part of the exhaust aftertreatment system Applicability of NOx adsorption catalyst limited to regions where sulfur content is below 30 ppm Stratified lean combustion system currently not applicable worldwide
Fuel Efficiency Gains by the Various Technology Generations. V8 4.0l Inline6 3.0l Basis = Double VANOS - 10 % - 18 % - 21 % -8 % - 29 % Double VANOS * in EU test cycle VALVETRONIC High Precision Injection in Lean Burn Mode Upgrading g by Twin Turbo with High Precision Injection TwinPower Turbo with High Precision Injection and VALVETRONIC The Next Step in a Logical Row: TVDI. Turbocharging Valvetronic Direct Injection
Variabilities: Valvetronic Variable Valvelift. Variabilities: Valvetronic Variable Valvelift. Expansion Compression IO EO EC IC Normal Operation IO EO EC IC Low Valve Lift
Variabilities: Valvetronic Variable Valvelift. Normal Operation Low Valve Lift Valve Phasing Variabilities: Valvetronic Variable Valvelift. Phasing Masking 10 valve lift [mm] 8 ]Phasing-range 6 4 2 0 Different valve lift 0 10 20 30 40 50 60 70 80 90 100 110 excenterangle [% EW ] h h : masking height (2 mm) s : masking gap (0,4 mm) : angle (180 ) : orientation (90 ) s High swirl with different valve lifts (phasing) High tumble at low valve lifts with double - masking
Variabilities: Cam Phasing Variable Valve Timing. Normal Operation Early Inlet Valve Opening Late Inlet Valve Closing Large Valve Overlap Standard Loadpoints in Engine Loadmap. 1.4 1.2 290 1.0 Load [kj/l] Engine 0.8 0.6 0.4 0.2 800 1000 00 0.0 1000 3000 5000 7000 Standard Load Points Engine Speed [RPM] Efficiency improvements require complex mechanical and geometry changes Complexity of grid generation increases significantly
Overview Simulation benefits in the framework of the powertrain development process Boundary conditions for powertrain development Challenges and requirements for incylinder CFD CAE organisation at BMW Powertrain The incylinder simulation workflow at BMW Powertrain Development Challenges and requirements in powertrain CFD CFD in the framework of the engine development and simulation process Examples Summary & Outlook of CFD applications in powertrain development at BMW Development and trends Summary Outlook Efficient Meshing Strategies: Premeshing of Constant Grid Parts. Geometry model Intake Port Exhaust tport Combustion Chamber Piston Premeshing of constant geometry parts Interface Exhaust Port Spark Plug cut free Constant surface meshes Interface Intake Port Piston Combustion Chamber Exhaust Port Spark Plug cut free Intake Port Pistongrid for Extrusion
Efficient Meshing Strategies: Local Remeshing. Valve movement Sheared Cells Bad cell quality often locally confined to small areas (e.g. masking gap) Efficient Meshing Strategies: Extrusion Mesh. Standard mesh Extrusion mesh Piston movement is mostly realized by extrusion mesh Constant mesh quality in combustion chamber region during most of the piston movement
July 6th 2009 Efficient Meshing Strategies: Hex Mesh in Valve Gap. VH = 0 0.28 0.55 0.95 28 mm 55 95 VHV=H 0 0.05 0.07 0.13 = 13 05 07 0 0.28 0.55 0.95 28 55 95 mm mm Hexahedra mesh in valve g gap p for low valve lifts in Valvetronic p part lift conditions Valve opening at 0.05 mm possible vs. 0.3 mm standard. July 6th 2009 Efficient Meshing Strategies: Result.
Benefit of New Workflow: Time for Charge Cycle Simulation. Conventional Method: Base: new geometry & valvetrain data & boundary conditions 1d 15-20d 4d 1d 21d -26d Change: boundary conditions and/or engine speed 4d 1d 5d New Method: CFX & ICEM (Tetra, Quad) Base: new geometry & valvetrain data & boundary conditions 2d 5d 1d 8d Change: boundary conditionsmanual and/or engine interaction speed by qualified personel required 4d 1d 5d Geometry repair Mesh generation CPU Simulation Postprocessing Benefit of New Method: Time for Charge Cycle Simulation. Conventional Method: Base: new geometry & valvetrain data & boundary conditions 1d 15-20d 4d 1d 21d -26d Change: geometry (ports, combustion chamber and/or piston) 1d 5-10d 4d 1d 11d -16d New Method: CFX & ICEM (Tetra, Quad) Base: new geometry & valvetrain data & boundary conditions 2d 5d 1d 8d Change: geometry (post, combustion chamber and/or piston) 1d 5d 1d 7d Geometry repair Mesh generation CPU Simulation Postprocessing
Vergleich mit bisheriger Berechnungsmethode Bearbeitungszeit simulationsbasierte Vorauslegung 1.4 1.2 Load variation WOT 290 Engine Lo oad [kj/l] 10 1.0 0.8 0.6 0.4 Speed variation 0.2 800 1000 0.0 1000 3000 5000 Engine Speed [RPM] 7000 Load points previously Possible load points now Incylinder Workflow: Result Mixture Preparation.
0.18 0.16 0.15 0.14 0.13 0.12 0.11 0.10 Füllkanal Tumblekanal Variante 1 Variante 2 Variante 3 Variante 4 Variante 7 N53: Füllkanal Saugmotor Optimierungsaufgabe 0.0 0.5 1.0 1.5 2.0 2.5 3.0 Tumble [-] [-] N55: Tumblekanal Turbomotor Overview Simulation benefits in the framework of the powertrain development process Boundary conditions for powertrain development Challenges and requirements for incylinder CFD CAE organisation at BMW Powertrain The incylinder simulation workflow at BMW Powertrain Development Challenges and requirements in powertrain CFD CFD in the framework of the engine development and simulation process Examples Summary & Outlook of CFD applications in powertrain development at BMW Development and trends Summary Outlook CFD in the Development Process at BMW Powertrain. IC Engine Concept Package Design 0.09 zunehmender Massenstrom Durchflussbeiwert [-] Trade-Off zunehmende Ladungsbewegung 1D-Simulation 3D-Simulation Analysis Concept Definition Design Series Development 3D-Simulation Optical Testing Mixture Preparation Combustion Analysis Charge Motion 1-Cylinder Testing Analysis 3D-Simulation Heat Transfer Kraftstoff Multi lticylinder Testing Analysis 3D-Simulation NOx- Sensor Gehäuse Detailed Analyses Spark Displacement Injector- Internal Flow Nadel
July 6th 2009 Turbocharger Development: Process and Interfaces. steady state mass flow through wastegate port vs. wastegate position definition of wastegate position throughout map transient simulation of exhaust system hot-end July 6th 2009 Turbocharger Development: Process and Interfaces. transient simulation of exhaust system yields heat transfer coefficients ffi i t Simulation of component
Overview Simulation benefits in the framework of the powertrain development process Boundary conditions for powertrain development Challenges and requirements for incylinder CFD CAE organisation at BMW Powertrain The incylinder simulation workflow at BMW Powertrain Development Challenges and requirements in powertrain CFD CFD in the framework of the engine development and simulation process Examples Summary & Outlook of CFD applications in powertrain development at BMW Development and trends Summary Outlook Summary and Outlook. Boundary conditions i for power train development are set by legislative l i requirements regarding emissions and expectations of customers regarding consumption and power output Complex technologies for BMW EfficientDynamics engines lead to high requirements regarding grid generation process An automated grid generation and incylinder simulation workflow has been developed and is successfully being applied Incylinder CFD is an established tool in the framework of the BMW powertrain development process. Demands from interfaces to many other applications (other CFD/mechanical) must be satisfied Plenty of application areas remain requiring further dedicated development and the challenges for CFD in the field are high due to the complex interaction of numerous physical phenomena Incylinder activities at ANSYS should still be enhanced, in order to provide more than the PistonGrid framework inside which the customer is required to develop methods