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Research on GDI Internal Combustion Engines @ IITDelhi

Research by Prof. P.M.V. Subbarao at IIT Delhi focuses on modeling and predicting new features for GDI engines. The study covers the effects of geometric and spray parameters like injector location, spray orientation, and droplet diameter. The research includes CFD package requirements, turbulence generation, charge homogenization, and comparison of DISC and Pent Roof chamber geometries for optimal performance.

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Research on GDI Internal Combustion Engines @ IITDelhi

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  1. Research on GDI Internal Combustion Engines @ IITDelhi P M V Subbarao Professor Mechanical Engineering Department I I T Delhi Models to Predict New & Better Anatomy of Artificial Horse …..

  2. Tracking of Post Injection Events inside Cylinder

  3. New Knowledge Required to Develop GDI Engines • Effect of Geometrical and Spray Parameters • Injector location, • Spray orientation, • Injection timing, • Droplet diameter, • Spray cone angle, • Type of spray, • Fuel temperature

  4. Required Features of CFD Package • Capability to model flow in complex geometry • Capability to model turbulent flow • Capability of handling moving boundaries • Generalized multi-block capability • Spray model • Robust Algorithm

  5. Deforming Mesh

  6. Initialize all variables Droplet Tracking Algorithm Source terms of Gas Phase Equation = 0 Solve for Gas Phase Equations Solve for Droplet Equations Cal. Gas Phase Source Terms Converged ? No ya Next Time Step

  7. Results : Turbulence Generation

  8. Turbulence Generation in DISC Chamber Geometry

  9. Turbulence Generating Geometry

  10. Turbulence Generation

  11. Turbulence Generation in Different Geometries

  12. Effect of Neck Size on Turbulence Generation

  13. Turbulence Generation

  14. Other Results Obtained from the Code • Effect of Compression ratio on turbulence • Effect of speed on turbulence • Effect of speed on squish generation

  15. Results : Quality of A/F Mixture

  16. Study of Charge Homogenization • Index for deviation from homogeneity

  17. DISC Chamber Geometry Studies

  18. Charge Formation at 100 micron, 1200 Cone Angle

  19. Charge Formation at 25 micron, 300 Cone Angle

  20. Selection of Optimum SOI

  21. Effect of Spray Cone Angle on Charge Homogeneity

  22. Selection of Optimum Droplet Size

  23. Conclusions for DISC Chamber • The Spray Cone Angle should be as wide as possible • Spray impingement is not avoidable even for smallest droplets • Bigger droplets travel fast to impinge fast – better for further homogenization • The earlier the better • The bigger the better • The wider the better for homogenization

  24. Pent Roof Geometry with Central Injector • Similar studies : 25 – 100 micron, 600 to 1200 • SOI – 900 aTDC (Suction)

  25. Pent Roof Chamber:Optimum Parameters

  26. Comparison of DISC and Pent Roof Chamber Geometries

  27. Conclusion Pent Roof > DISC for homogenization

  28. Charge Homogenization in Pent Roof Chamber with Side Injector • SOI = 900 • Orientation – 300 from horizontal • Droplet Dia – 100 to 25 micron • Spray Angle – 900 to 1200

  29. Optimum injection conditions for Pent Roof chamber with Side Injector

  30. Comparison of Side Injector with Central Injector

  31. Part Load Results: Generation of Stratified Charge

  32. Study of Charge Stratification in Different Configurations • DISC ChamberPent Roof with Central InjectorPent Roof with Side Injector • SOI – varied • Tumble Ratio - varied

  33. Stratified Charge Formation in Central Injector with Tumbling Flow

  34. Parametric Studies • Tumble Ratio (Maximum gas velocity/piston speed) – 5 to 7.5 • SOI – 900 to 1200 bTDC (Compression) • Dia - 100 micron to 25 micron

  35. Optimum Injection Parameters for Best Stratification

  36. Stratified Charge Formation in Side Injector with Tumbling Flow

  37. Parametric Studies • Drop Dia. – 100 micron • Compact Spray – 450 • Orientation of Injector from horizontal – 300, 450,600 • SOI – 900, 1200

  38. Optimum Injection Parameters for Pent roof Geometry with Side Located Injector

  39. Comparison of Side Injector & Central Injector

  40. Experimental Development • A special purpose test rig was developed in IC engine laboratory of Mechanical Engineering Department, IIT Delhi, to investigate the characteristics of GDI engines. • A four stroke engine of Kawasaki Bajaj two wheeler is modified to work as GDI engine. • A mechanical driven petrol injector is placed in the cylinder head. •  Pistons with various geometries of cavities (Cylindrical, Conical & Spherical) are tested using a compression ratio of 9.3 at various speeds. • Following preliminary results are obtained.

  41. Control System of A Conventional I.C. Engine

  42. Engine Geometric Ratios Engine Compression Ratio Cylinder Bore-to-Stroke Ratio Kinematic Rod Ratio

  43. Controlled Compression Ratio Instantaneous Piston Displacement:

  44. Conclusions • GDI Engine Technology is an obvious future choice. • Extensive CAD is essential for the development of GDI Engines. • CAD combined with experimental study will develop a better engine with faster development cycle. • More avenues for future research and development.

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