1 / 26

Airflow and Fuel Spray Interaction in a Gasoline DI Engine

Airflow and Fuel Spray Interaction in a Gasoline DI Engine. Professor Morgan Heikal Internal Combustion Engines Group University of Brighton & Ricardo UK Ltd. Presentation outline. Area of Study Test Equipment and Methods Mie scatter studies Backlighting studies CFD analysis

alice
Download Presentation

Airflow and Fuel Spray Interaction in a Gasoline DI Engine

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Airflowand Fuel Spray Interaction in a Gasoline DI Engine Professor Morgan Heikal Internal Combustion Engines GroupUniversity of Brighton & Ricardo UK Ltd

  2. Presentationoutline • Area of Study • Test Equipment and Methods • Mie scatter studies • Backlighting studies • CFD analysis • Results evaluation • Conclusions

  3. Area of Study • Airflow and Fuel Spray Interaction • Early injection regimes • Variation of spray characteristics with injection timing • Distortion of fuel jet by air flow • Comparison of experiment with CFD analysis • To check on experimental findings

  4. throttle intakeplenum cam box cam pulleys cylinder head exhaust cylinder liner timing belt flywheel pistonhead pistonextension Test Engine • Ricardo ‘Hydra’ G-DI research engine • Single-cylinder, wall-guided • Full-quartz optical cylinder liner • Heated Piston

  5. EngineCombustion Chamber • Top entry, pent roof construction • Injector • side mounted • swirl atomiser • 70o included angle • Spark Plug • centrally located • 2d piston profile • 75mm stroke • 74mm bore Get better image and re-do layout New diagram including piston profile and spark plug

  6. Optical Methods I • Mie scatter • 1000 rev/min, WOT, SOI ATDC 20, 40, 60o

  7. Optical Methods II • Backlighting studies • 1000 rev/min • WOT • SOI • ATDC 20, 40, 60o

  8. CFD Analysis • CFD Code • Ricardo VECTIS • Fuel spray model • Discrete droplet model (DDM) • Ensemble of droplet parcels • Introduction rate given by • injection rate • spray angle • droplet size distribution • Secondary break-up sub-models • Droplet turbulence interaction and impingement • Secondary break-up model – Reitz-Diwakar

  9. Raw average image • Thresholded image • Masked image Mie Scatter Results I

  10. Edge detection Injection progress Mie Scatter Results II

  11. SOI = 20oATDC • SOI = 40oATDC • SOI = 60oATDC • SOI = 80oATDC Mie Scatter Results III

  12. Averaged image • intake valves • Edge detected • intake valves Backlighting Results I

  13. 30 pixel 60 pixel 90 pixel Backlighting Results II • Spray width intensity profile analysis 30 pixel 60 pixel 90 pixel

  14. spray shadow • central plane • vapour • air speed • nd2 • air speed on valve CL CFD Analysis I

  15. CFD Analysis II • Comparison of results of CFD analysis with experiment

  16. CFD Comparison with Experiment • SOI 60o CA • 8o ASOI • SOI 60o CA • 21o ASOI

  17. IntensityvariationwithSOI Analysis of Mie Scatter Data

  18. Average spray width at 3 depths Backlighting evidence • For 1.2, 1.6, 2.0, 2.4, 2.9ms ASOI • Width decreases with later SOI

  19. Comparison with CFD • CFD nd2 values • Similar increase with SOI • Similar fluctuations CFD CFD Mie scatter

  20. Intensity Increase with SOI • Central plane intensity only • Jet squeezed by incoming air from valves • Plume shape changed • Flattened in cross-tumble plane • Broadened in tumble plane • More fuel is maintained in central plane • Due to increased valve lift and air flow with later SOI • Could have been due to changes in droplet size • Checked against Begg(2003) and eliminated

  21. Intensity Irregularity with SOI • Comes from jet flapping • Seen in vapour distribution • Valid indicator for early stages • Clearest visualisation

  22. Measured Jet flapping • Video representation • Jet flap at start • As CFD image • Despite average image • Rotational oscillation? • Takes fuel in and out of central plane • Explains intensity fluctuation with SOI

  23. Backlighting Image • Oscillation also seen in this plane

  24. Backlighting Image • Oscillation also seen in this plane

  25. Conclusion • For early injection, incoming air acts on fuel jet • Air flow from two valves flatten jet • Fuel squeezed towards central pane • Effect increases with SOI delay • Shows as increasing Mie signal coverage and intensity • Due to increasing air flow as valve opening and piston speed increase • Narrowing seen in other plane • Fuel jet is deflected downwards Jet is seen to oscillate • Visible from Mie and backlighting data perspective • Manifests as irregularity in Mie signal through injection process CFD Analysis • Confirms effect if air inflow on jet • Predicts oscillation of jet • Is in general good agreement with experiment Single plane data can be difficult to interpret

  26. Close • Thank you for your attention! • Any questions?

More Related