1. C & R TECHNOLOGIES 303.971.0292 Fax 303.971.0035 www.crtech.com Modeling IC Engines and Turbochargers Using SINDA/FLUINT and Sinaps ® Sinaps, C&R Thermal Desktop, RadCAD and FloCAD are registered trademarks of C&R Technologies. SpaceClaim is a registered trademark of SpaceClaim Corporation.

2. C&R TECHNOLOGIES www.crtech.com Overview l Detailed (high temporal fidelity) IC Engine Model Inline 6 cylinder, atmospherically aspirated Seeking temperature/pressure/flow histories over a cam cycle as a function of RPM l Turbocharged IC Engine Model Add compressor, turbine, intercooler, waste gate, pop-off valve Modify intake and exhaust Seeking: Parametric sweeps, including TC speed vs. Engine speed Fast Transient: TC performance over a cam cycle (pressure waves) Slow Transient: Engine speed variations (boost lag, valve responses) l Full documentation and models are available at www.crtech.com www.crtech.com

3. C&R TECHNOLOGIES www.crtech.com Wave Propagation l SINDA/FLUINT is a finite difference, finite volume solver, not a method of characterisics (MOC) solver Can handle much more complex phenomena than can MOC The solution is implicit: can take large time steps. So time steps must be constrained to capture wave motions Waves appear, even though they aren’t explicitly modeled l Coarse axial resolution is OK for demonstration and preliminary design* Easy to increase resolution at any time l Can choose to neglect high-frequency terms at any point in the fluid network Can opt instead for quasi-steady solutions for faster run times * For liquid systems, low resolution is tolerable even for detailed design work. 100mm long by 10mm diameter dead-end tube with sinusoidal and step function excitations

4. C&R TECHNOLOGIES www.crtech.com Sample Engine Specs. l 4-cycle inline 6 cylinder, with SOHC 3.7L displacement 9:1 compression ratio (CR) Firing sequence: 1, 5, 3, 6, 2, 4 Fixed valve lift profile Easy to vary if needed l Intake and Exhaust Intake manifold 85x110x210 mm box, with 500mm long by 45mm diameter runners, with notional air filter losses Exhaust manifold blended runners, 356mm long by 41.3mm diameter, with a 305mm long 6-1 transition section Exhaust pipe 3.05m long by 57.2mm diameter with notional muffler and catalytic converter losses Intake valve lift profile from 0 TDC

5. C&R TECHNOLOGIES www.crtech.com Simplifying Assumptions l Simplified Combustion Event Cylinder was a boundary condition, not a focus of the model Instant heating by 2200K over intake manifold temperature at 0 TDC l Cylinder Heat Transfer Convective and radiative heat transfer used, adjusted to yield roughly 1/3 rd total loss to engine block l Piston Motion Pure sinusoid was used Could easily apply more realistic motion given crank and rod lengths l Valve Flow Resistance Sharp annular gap assumed, modeled as an effective orifice Verified that within-cylinder axial fluid motions (e.g., knocking) could be neglected for this model: the cylinder could be a single control volume l Engine RPM Prescribed as an input: no vehicle/load model used l Manifolds Coarse axial resolutions (L/D ~ 5) were used, with few additional irrecoverable losses. These could be easily modified based on an actual design.

6. C&R TECHNOLOGIES www.crtech.com Postprocessed Sinaps Network

7. C&R TECHNOLOGIES www.crtech.com Parametrically Defined

8. C&R TECHNOLOGIES www.crtech.com Sample Results Cylinder Temps at 4000RPM

9. C&R TECHNOLOGIES www.crtech.com Sample Results: Pressures and Flows at 6000RPM, Cylinder #1

10. C&R TECHNOLOGIES www.crtech.com Next Model: Turbocharged l Intake Modifications 150mm long by 50mm diameter intake runners 610mm long by 100mm diameter pipe as manifold l Waste Gate Details of servo line, dynamic stem motions etc. could have been included, but were neglected since this is not the focus Proportional control valve, open at 2.2 bar (intake manifold), closed at 2.0 bar Proportional control (vs. bang-bang) used for convenience: allows steady state solutions l Pop-off Valve Proportional control valve, open at 2.4 bar, closed at 2.2 bar l Intercooler Notional/place-holder, despite heat exchangers being a forté: this was not the focus Achieved minimal cooling, had minimal flow resistance l 5 Compressors and 6 Turbines were evaluated CompAero and TurbAero software (www.turb-aero.com) employedwww.turb-aero.com

11. C&R TECHNOLOGIES www.crtech.com Compressor l Design Point: 70000 RPM P ratio = 2.5 4000 RPM engine 0.245 kg/s 25°C, 86kPa inlet (total) l Design Summary: Centrifugal with basic volute-type outlet, 49mm inlet diameter Vaneless vaned compressors were also evaluated 72% efficiency (T-T)

12. C&R TECHNOLOGIES www.crtech.com Turbine l Design Point: 70000 RPM P ratio = 2.61 (T-S) 4000 RPM engine 0.245 kg/s 695K, 324kPa inlet (total) 124kPa exit (static) 110% of est. power required by compressor l Design Summary: Radial, 94mm blade tip diameter Vaneless vaned compressors were also evaluated 82% efficiency (T-S)

13. C&R TECHNOLOGIES www.crtech.com Turbocharger Dynamics Rotational inertia ( I ) of whole turbocharger subsystem was estimated to be 7.68e-3 kg-m 2 l Notional friction (f) as a function of RPM l Current net torque (T net ) used to co-solve 1 st order ODE: T net – f*  = I *d  / dt l Can also use in a sizing mode parametrically sweep  to find the balance point (zero net torque)

14. C&R TECHNOLOGIES www.crtech.com System Network: Detailed Model

15. C&R TECHNOLOGIES www.crtech.com Sample Results Pressures at 3000RPM, Cylinder #1

16. C&R TECHNOLOGIES www.crtech.com System Network: Simplified Model l Replace engine with steady-flow, steady heating model based on averages of detailed model as a function of RPM l Change focus from small to large time scale including steady state l Used to generate TC speed at balance point For use as an initial condition in detailed model

17. C&R TECHNOLOGIES www.crtech.com Sample Results: Parametric Sweeps

18. C&R TECHNOLOGIES www.crtech.com Sample Results: Engine Transient

19. C&R TECHNOLOGIES www.crtech.com Sample Results: Engine Transient Compressor surges

20. C&R TECHNOLOGIES www.crtech.com Geometry (CAD/FDM/FEM) Model Development l Sinaps ® is nongeometric SINDA/FLUINT models can be created from CAD geometry too use any combination of: lumped parameter (network) finite difference finite element l C&R Thermal Desktop ® FloCAD for fluid modeling Includes turbomachinery, rotating passages (secondary flows) RadCAD for radiation l CRTech SpaceClaim ® CAD import or generation healing, defeaturing, meshing

21. C&R TECHNOLOGIES www.crtech.com Conclusions l CRTech tools are applicable to: IC engine fuel/air system design studies Turbocharger design (including IC engine interactions) at both short and long time scales Basic models are available as starting points l Possible Extensions Exhaust Gas Recirculation (EGR) integration Waste gate control systems and detailed design Variable geometry turbines (VGT) Multiple turbochargers (parallel or series) In-system turbine and compressor design optimization Requires development cooperation with meanline analysis software