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A Numerical Approach to Vehicle Thermal Management of Dynamic Driving Cycles STAR Global Conference 2014 Wien, March 17th 2014 Mario Disch, Walter Bauer, Daimler AG

Agenda How do computational methods contribute to the prototype development process at Mercedes-Benz? • Motivation • Vehicle Thermal Management Approach • Transient Simulation vs. Measurement • Conclusions and Future Work 2 A Numerical Approach to Vehicle Thermal Management of Dynamic Driving Cycles

Motivation Vehicle Thermal Management (VTM) for dynamic driving cycles  Transient thermal analysis of temperature components for a passenger car Mont Ventoux 1433 m a. s. l. Malaucène 410 m a. s. l.* T t Source: Google Earth * meters above sea level 3 A Numerical Approach to Vehicle Thermal Management of Dynamic Driving Cycles

Vehicle Thermal Management Approach Co-Simulation of a transient Solid Model (conduction and radiation) with a steady state Fluid Model (convection) Fluid Model (STAR-CCM+) Detailed modelling of the • Underhood flow • Coolant circuit • Exhaust flow • Oil circuit, in order to capture the internal heat transfer of the engine and the exhaust system. 4 A Numerical Approach to Vehicle Thermal Management of Dynamic Driving Cycles

Vehicle Thermal Management Approach Co-Simulation of a transient Solid Model (conduction and radiation) with a steady state Fluid Model (convection) Fluid Model (STAR-CCM+) Detailed modelling of the • Underhood flow • Coolant circuit • Exhaust flow thermostat valve • Oil circuit, in order to capture the internal heat transfer of the engine and the exhaust system. 5 A Numerical Approach to Vehicle Thermal Management of Dynamic Driving Cycles

Vehicle Thermal Management Approach Co-Simulation of a transient Solid Model (conduction and radiation) with a steady state Fluid Model (convection) Fluid Model (STAR-CCM+) Detailed modelling of the • Underhood flow • Coolant circuit • Exhaust flow • Oil circuit, in order to capture the internal heat transfer of the engine and the exhaust system. 6 A Numerical Approach to Vehicle Thermal Management of Dynamic Driving Cycles

Vehicle Thermal Management Approach Co-Simulation of a transient Solid Model (conduction and radiation) with a steady state Fluid Model (convection) Fluid Model (STAR-CCM+) Detailed modelling of the • Underhood flow • Coolant circuit • Exhaust flow • Oil circuit, in order to capture the internal heat transfer of the engine and the exhaust system. 7 A Numerical Approach to Vehicle Thermal Management of Dynamic Driving Cycles

Vehicle Thermal Management Approach Co-Simulation of a transient Solid Model (conduction and radiation) with a steady state Fluid Model (convection) Solid Model (STAR-CCM+) Detailed modelling of 4821 parts 𝑅 𝐷𝑝𝑛𝑐. and 151 material properties. Prediction of the heat transfer 𝑅 𝑆𝑏𝑒. mechanisms taking place inside 𝑅 𝐷𝑝𝑜𝑒𝑣𝑑𝑢𝑗𝑝𝑜 the vehicle structure based on the heat released inside the combustion chamber. 𝑅 𝐷𝑝𝑜𝑤𝑓𝑑𝑢𝑗𝑝𝑜 8 A Numerical Approach to Vehicle Thermal Management of Dynamic Driving Cycles

Transient Simulation vs. Measurement Replicated Up-hill Drive • Test car – Mercedes-Benz E-Class 220 CDI – in the climatic wind tunnel • The driving cycle is derived from the Mont Ventoux test track. It consists of a sequence of12 full throttle acceleration phases. v transient steady state preconditioning 0 1 2 11 12 length /km 9 A Numerical Approach to Vehicle Thermal Management of Dynamic Driving Cycles

Transient Simulation vs. Measurement Replicated Up-hill Drive Temperature prediction of the turbocharger housing * Referenced Temperature: delta T= T-T test_initial 10 A Numerical Approach to Vehicle Thermal Management of Dynamic Driving Cycles

Transient Simulation vs. Measurement Replicated Up-hill Drive Temperature prediction of the cylinder head * Referenced Temperature: delta T= T-T test_initial 11 A Numerical Approach to Vehicle Thermal Management of Dynamic Driving Cycles

Transient Simulation vs. Measurement Replicated Up-hill Drive Temperature prediction of the right and the left engine mount * Referenced Temperature: delta T= T-T test_initial 12 A Numerical Approach to Vehicle Thermal Management of Dynamic Driving Cycles

Transient Simulation vs. Measurement Replicated Up-hill Drive (real time=740 s) • Turn-around time 1 CPU 6 CPU 6 CPU 104 CPU 104 CPU 104 CPU >6 CPU >104 CPU (shared) April 2013 August 2013 March 2014 Prediction (multiple fluid computation) (event driven fluid computation) 13 A Numerical Approach to Vehicle Thermal Management of Dynamic Driving Cycles

Conclusions and Future Work Conclusions • Transient VTM approach combines transient solid computation with a sequence of steady state fluid computations including all the inner circuits. • The new VTM approach provides a good predictability for temperature, which has been validated with experimental data, especially for parts dominated by radiation and conduction. • High turn-around time is addressed by: - multiple fluid coupling scenario - parallelized solid computation - increasing computing performance 14 A Numerical Approach to Vehicle Thermal Management of Dynamic Driving Cycles

Conclusions and Future Work Future Work • Simulation of further driving cycles (urban driving cycles, stop & go, race track , …) • More detailed modeling of the coolant circuit (water pump as MRF-zone) • Adding the charge air path into the simulation water pump (MRF) dual stream T_compr. 15 A Numerical Approach to Vehicle Thermal Management of Dynamic Driving Cycles

Thank you ! 16 A Numerical Approach to Vehicle Thermal Management of Dynamic Driving Cycles

BACKUP Thorsten Schmitt, RD/FNE, xx.012.2014 17 A Numerical Approach to Vehicle Thermal Management of Dynamic Driving Cycles

Vehicle Thermal Management Approach Co-Simulation Coupling Procedure • The dynamics of the flow field are approximated by a sequence of steady state computations • 1D simulation results are applied as dynamic boundary conditions steady state FLUID Init. FLUID 𝑈 𝑋 Dynamic BC (1D GT-Suite) Dynamic BC (1D GT-Suite) 𝑔 Time (𝑢) Time 𝑔 (𝑢) [𝐿, 𝑙𝑕 [𝐿, 𝑙𝑕 [𝑡] [𝑡] 𝑡 , 𝑄𝑏] 𝑡 , 𝑄𝑏] 𝑢 𝑜 𝒈 (𝟏) 0 𝑔 0 (0) 𝑢 𝑜+1 = 𝑢 𝑜 + ∆𝑢 𝒈 (𝟐𝟏) 10 10 𝑔 (10) t+1 𝑔 (𝑢+1) 𝑔 t+1 (𝑢+1) ~1000 Its* ~1000 Its 𝑈 𝐺 𝑈 𝐺 transient ℎ 𝑢𝑠𝑏𝑜 ℎ 𝑢𝑠𝑏𝑜 SOLID 1x Δ t=10 s 0 Time / s * Its: Iterations 18 A Numerical Approach to Vehicle Thermal Management of Dynamic Driving Cycles

Vehicle Thermal Management Approach Model information Coolant Charge Models Solid Uhood Exhaust Circuit Oil Circuit Air Number of Cells (Mio.) 39.84 38.51 3.43 2.04 0.48 2.86 Mesh topology polyhedral hexahedral polyhedral polyhedral polyhedral hexahedral 19 A Numerical Approach to Vehicle Thermal Management of Dynamic Driving Cycles