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On the Potential of Transfer Port Injection Strategies for a Two-Stroke Engine
Technical Paper
2022-32-0057
ISSN: 0148-7191, e-ISSN: 2688-3627
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English
Abstract
The main drawback of an in-cylinder Low Pressure Direct Injection (LPDI) in a two-stroke engine is the difficulty of achieving a satisfactory vaporization level in low load conditions. The liquid droplets are characterized by large diameters and, when the temperature level and the velocity of the scavenging flow field are low, the time needed for the droplet vaporization and the homogenization with fresh air becomes too long to guarantee a suitable mixture formation. A transfer port injection allows a higher flexibility, due to the possibility of performing a mixed injection either directly in the cylinder or indirectly in the crank case, depending on the load request or engine speed. Also, an even lower injection pressure can be adopted with respect to an in-cylinder LPDI injection, which is relevant in case of lightweight and low power applications. On the other hand, the time available for the direct in-cylinder injection is limited to the scavenge phase.
In the present work, a detailed numerical analysis has been performed on a 15kW 300 cm3 two stroke engine for evaluating the potential of a transfer duct installation of a low pressure injector. The influence of the injection system positioning has been investigated by means of high fidelity three dimensional CFD simulations of both the scavenge and the spray processes. The engine model has been validated with experimental data acquired at the test bench on the engine operated in a homogenously scavenged configuration, equipped with a standard carburettor. The spray model has been validated with experimental data acquired during both an imaging test campaign for the analysis of the global spray evolution over time and a Phase Doppler Anemometry (PDA) analysis for a detailed sizing characterization of the spray. The paper shows the results of a sensitivity analysis on the fuel vaporization and short circuit, as well as air fuel mixing and homogenization, by varying the following parameters: choice of the transfer port (from first to fifth), injection direction (co-current or counter-flow) and injection timing.
Authors
Citation
Balduzzi, F., Romani, L., Ferrara, G., Trassi, P. et al., "On the Potential of Transfer Port Injection Strategies for a Two-Stroke Engine," SAE Technical Paper 2022-32-0057, 2022, https://doi.org/10.4271/2022-32-0057.Also In
References
- Ferrara , G. , Balduzzi , F. , and Vichi , G. An Innovative Solution for Two-Stroke Engines to Reduce the Short-Circuit Effects SAE 2012 World Congress & Exhibition SAE International 2012 10.4271/2012-01-0180
- Ohira , T. , Ikeda , Y. , and Nakagima , T. Cyclic Variation Due to Misfiring in a Small Two-Stroke Engine Culick , F. , Heitor , M. V. , and Whitelaw , J. H. Unsteady Combustion, Springer Netherlands, Dordrecht 978-94-010-7223-6 369 381 1996 10.1007/978-94-009-1620-3_16
- Ragg , P. , McKay , M. , and Brooks , R.
- Nesti , P.
- Duret , P. , Lavy , J. , Venturi , S. , and Allen , C. SCIP Simplified Direct Injection for Low Emissions Small Two-Stroke Engines 1999-01-3289 1999 10.4271/1999-01-3289
- Winkler , F. , Oswald , R. , Schogl , O. , Abis , A. , Krimplstatter , S. , and Kirchberger , R. Layout and development of a 300 cm 3 high performance 2S-LPDI engine SAE Technical Paper 2015-32-0832 2015
- Balduzzi , F. , Vichi , G. , Romani , L. , Ferrara , G. , Trassi , P. , Fiaschi , J. , and Tozzi , F. Development of a Low Pressure Direct Injection System for a Small 2S Engine. Part I - CFD Analysis of the Injection Process SAE Int. J. Engines 8 4 1885 1897 2015 10.4271/2015-01-1727
- Romani , L. , Vichi , G. , Ferrara , G. , Balduzzi , F. , Trassi , P. , Fiaschi , J. , and Tozzi , F. Development of a Low Pressure Direct Injection System for a Small 2S Engine. Part II - Experimental Analysis of the Engine Performance and Pollutant Emissions SAE Technical Paper 2015-01-1730 SAE International Warrendale, PA 2015 10.4271/2015-01-1730
- Balduzzi , F. , Vichi , G. , Romani , L. , and Ferrara , G. CFD Analysis of the Effect of the Injection Pressure on a Small 2S LPDI Engine SAE Technical Paper 2015-32-0760 2015
- Romani , L. , Vichi , G. , Balduzzi , F. , Bianchini , A. , and Ferrara , G. Fine-tuning of a two stoke engine in full power configuration provided with a Low Pressure Direct Injection system Energy Procedia 126 987 994 2017 10.1016/j.egypro.2017.08.251
- Kirchberger , R. "Two Stroke Combustion Engine," AT501986B1 2007
- Balduzzi , F. , Romani , L. , Tanganelli , A. , Bigalli , S. , and Ferrara , G. On the Effect of the Injector Position on Fuel-Air Mixture Preparation in a Two-Stroke GDI Engine SAE Technical Paper 2018-32-0040 2018 10.4271/2018-32-0040
- Ciampolini , M. , Bigalli , S. , Balduzzi , F. , Bianchini , A. , Romani , L. , and Ferrara , G. CFD Analysis of the Fuel-Air Mixture Formation Process in Passive Prechambers for Use in a High-Pressure Direct Injection (HPDI) Two-Stroke Engine Energies 13 11 2846 2020 10.3390/en13112846