1. Combustion and Flow Measurementin Piston-Cylinder Assemblies Harold Schock Michigan State UniversityMechanical EngineeringME444 Fall 2007

2. In-Cylinder Process Quantification

State measurement (average /local) temperature, pressure

Air-flow quantification

• Swirl meter

• Tumble meter

• Laser diagnostics

Species quantification

• Laser induced fluorescence

• Sampling valves (helenoid & mass spectrometer)

• Flame ionization detector

• Chem luminescence detector

3. SAE 2000-01-2798 The 3-D In-Cylinder Charge Motion of a Four-Valve SI Engine under Stroke,Speed and Load Variation Hans G. Hascher, Mark NovakTom Stuecken and Harold J. Schock Engine Research LaboratoryMichigan State University, East Lansing, MI James Novak Powertrain Operations Ford Motor Company, Dearborn, MI International Fall Fuels and Lubricants Baltimore, MarylandOctober 16-19, 2000 4. Outline

Engine and measurement system

Mean velocity vector fields

Turbulent kinetic energy

• Isosurfaces

• Average

• Planar distribution

Tumble and swirl ratios

• Fixed vs. moving origin

• Planar

Conclusions

5. Engine and Measurement System 6. Model and Make Ford 4-Valve 4.6L Ford 4-Valve 5.4L Bore and Stroke 90.2 mm / 90.0 mm 90.2 mm / 105.4 mm Connecting Rod Length 150.7 mm 170.0 mm Valve Activation DOHC DOHC Intake Valve Diameter 37.0 mm 37.0 mm Exhaust Valve Diameter30.0 mm 30.0 mm Maximum Valve Lift10.02 mm at 120 CAD 10.02 mm at 120 CAD Zero CAD Intake TDC Intake TDC Intake Valve Opening6 CAD Before TDC 6 CAD Before TDC Intake Valve Closure250 CAD After BDC 250 CAD After BDC Exhaust Valve Opening126 CAD After TDC 126 CAD After TDC Exhaust Valve Closure16 CAD After TDC 16 CAD After TDC Compression Ratio 9.85 : 1 9.40 : 1 Piston Top FlatFlat Prototype Engine Specifications 7. Schematic of the LDV Setupfor 3-D Measurements 8. Coordinate System inside the Cylinder Volumewith Ten Measured Planes 9. Port Geometry with Pentroof Combustion Chamber at BDC for the 4.6L Setup 10. Calculations Grid for 127 MeasurementLocations in One Horizontal Slice 11. Mean Velocity Vector Fields 12. Mean Velocity Comparison in the Two Center Planesfor the 4.6L Setup WOT, between 600 rpmand 1500 rpm at 130 CAD Mean Velocity Comparison in the Two 13. Mean Velocity Comparison in the Two Center Planesfor the 5.4L Setup WOT, between 600 rpmand 1500 rpm at 130 CAD 14. Mean Velocity Comparison in the Center Plane for the 4.6L Setup Part Throttle Conditions,between 600 rpm and 1500 rpm at 130 CAD 15. Mean Velocity Comparison in the Two Center Planesfor the 4.6L Setup WOT, between 600 rpmand 1500 rpm at 243 CAD 16. Mean Velocity Comparison in the Two Center Planesfor the 5.4L Setup WOT,between 600 rpmand 1500 rpm at 243 CAD 17. Mean Velocity Comparison in the Center Planefor the 4.6L Setup Part Throttle Conditions,between 600 rpm and 1500 rpm at 243 CAD 18. Mean Velocity Distribution at z = 45mm in theMain Tumble Plane for the 5.4L Setup, at 600 rpmand 1500 rpm, and a Crank Angle of 130 Degrees 19. Turbulent Kinetic Energy

Isosurfaces

Average

Planar Distributions

20. Turbulent Kinetic Energy 21. Isosurfaces of TKE at 75 CAD for 4.6L, WOT at 600 rpm (left),IS-Level = 18.0 m 2 /s 2and for 4.6L, Part Throttle at 1500 rpm (right),IS-Level = 90.0 m 2 /s 2(scaled to 600 rpm: 14.4 m 2 /s 2 ).J/kg = m 2 /s 2 22. Isosurfaces of TKE 5.4L, WOT at 600 rpmat 298 CAD (left), IS-Level = 3.8m 2 /s 2and at313 CAD (right), IS-Level = 3.0m 2 /s 2 . J/kg = m 2 /s 2 23. Specific TKE for Nine Measured Planes for the 4.6L,Part Throttle Setup at 1500 rpm(TKE Axis Scaled to Lower Engine Speed) 24. Cylinder Coordinate Systemwith Moving Origin about the Instantaneous Center of the Volume Cylinder Coordinate Systemwith Fixed Origin at theTop Dead Center z z x y BDC x y TDC 25. Angular momentum per unit mass can be written as Hence, the angular momentum around the principal axis is Using the moment of inertia around the principal axis, The tumble ratio per specific CA can be defined 26. x-Tumble Ratios around the Moving Originfor All Six Engine Setups 27. x-Tumble Ratios around the Fixed Originfor all Six Engine Setups 28. x-Tumble Ratios around the Fixed Originfor the 4.6L WOT Setup at 600 rpm 29. Conclusions

• • The measured velocities and flow patterns are mildly sensitive to the bore/stroke ratio studied, flow velocities scale with piston speed changes, and flow patterns diverge significantly under the changes in the throttle conditions investigated.

• • Normalization of total turbulent kinetic energy to specific turbulent kinetic energy can obscure important aspects of the flow, such as the increase in total TKE late in compression for the 5.4L setup, WOT, 1500 rpm.

30.

• • A similar sickle-shaped, TKE-isosurface structure appeared in almost all engine setups, at and after BDC.Exception: Part throttle at 600 rpm.

• • The fluctuating part of the measured velocities, calculated as TKE,after BDC, exhibited similar exponential decay, between different four-valve engine setups and intake configurations.

• • Due to the absence of counter-rotating vortices in this study, tumble ratios did detect major changes in the mean flow. Three dimensional planar tumble ratio plots vs. crank angles provide a significant improvement in flow description compared to thebulk two-dimensional plots.

Conclusions 31.

• Although the general shape of a bulk tumble ratio curve vs. crank angle may be independent of the calculation center, significant differences in important regions can occur based on the reference chosen.

• Mean velocity collision regions contribute to the increase of TKE.

• The 5.4L configuration exhibited significant TKE gradients late in compression.

Conclusions 32. SAE 2000-01-2799 A Comparison of Modeled and Measured 3-DIn-Cylinder Charge Motion Throughout the Displacement of a Four-Valve SI Engine Hans G. Hascher and Harold J. Schock Engine Research LaboratoryMichigan State University, East Lansing, Michigan Oshin Avanessian and James Novak Powertrain OperationsFord Motor Company, Dearborn, Michigan International Fall Fuels and Lubricants Baltimore, MarylandOctober 16-19, 2000 33. 34. 35. 36. Modeled and Measured Mean Velocity Distributionwithin the Main Tumble Plane for the 4.6L,WOT Setup at 75 CAD during Intake Stroke 37. 38. 39. 40. 41. 42. 43. 44. 45. 46.

• • The modeled and measured mean flow patterns match well in amplitude and direction for the investigated engine setup.

• • Differences in the mean flows occurred mostly in the outer regions of the cylinder, away from the main tumble plane. The flow differences in the off-center planes indicate the need for additional modeling effort. In multi-cylinder engines, the modeling should include evaluation of wave dynamics, associated with the intake and exhaust and other cyclic phenomena that can influence in-cylinder flows.

• • Prediction of tumble showed reasonable agreement with the measured results. Investigation for other geometries would allow one to determine if tumble ratio vs. crank angle is a useful descriptor of engine flows.

Conclusions 47.

• • The prediction of turbulent kinetic energy matches well after BDC, but exhibits significant differences during the intake stroke, both in amplitude and location. Improved turbulencemodels and higher grid resolution clearly need to be implemented if one is to resolve the significant flow details.

• • For engines with a similar geometry to the one studied, simulated flows using current RANS models to represent internal flows can predict general flow features. However, they are unlikely to be useful for prediction of heat transfer, ignition events, flame propagation rates or stratified charge engine performance.

Conclusions,continued 48. 49. Undelayed Image(crankangle = 90 degrees) Delayed Image(crankangle=90 degrees, delay=70s) Delayed & Undelayed Images 50. Test Rig for Flow Control Experiments 51. Open Port 52. Tumble Plate 53. Swirl Plate 54. 55. 56. 57. 58. 59. 60. 61. 62. CONFIGURATION A 63. CONFIGURATION B 64.

MTV technology provides a revolutionary new tool for quantifying engine combustion chamber flows

Analysis of approximately 400 cycles is necessary to determine averages which can be used for comparative evaluations (for this engine configuration)

Cycle-to-cycle variability requires that a statistical description of combustion chamber flows be evaluated

CMCVs have a profound influence on the flowfield, even to late compression

Summary and Conclusions 65.

Nature of the CMCV influence depends on the geometry of the CMCV as well as the induction system each new geometry is likely to produce different flows

The valve timing difference studied also had an influence on the flowfield to late compression

Circulation PDFs comparisons showed considerable differences for the cases studied

Other FM PDFs descriptions should be examined and the results compared to combustion events

Summary and Conclusions