On the Effect of the Injector Position on Fuel-Air Mixture Preparation in a Two-Stroke GDI Engine
Published October 30, 2018 by SAE International in United States
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Modern injection systems are characterized by low cost, light weight and diversified components based on a mature technology. In addition, the constant growth of computational resources allows an in-depth understanding and control of the injection process. In this scenario, increasing interest is presently being paid to understand if an application of such technologies to small two-stroke engines could lead to a return to popularity in place of the more widespread use of the four-stroke engine. Indeed, the possibility of achieving a drastic reduction of both specific fuel consumption and pollutant emissions would completely reverse the future prospect of the two-stroke engine. The authors in previous studies developed a low pressure direct injection (LPDI) system for a 300 cm3 two-stroke engine that was ensuring a performance consistent with a standard four-stroke engine of similar size. The main drawbacks of the system were the large time required for delivering the fuel and the incomplete vaporization in some working conditions, due to the large size of the injected droplets. In this study, the use of a single high pressure injector with an operating pressure of 100 bar was analyzed. An optimization study was carried out in order to identify the best injector configuration for the GDI system. The results of the preliminary 3-D CFD study are here reported. The effect of the injector positioning and injection timing on the spray vaporization, mixture homogenization and fuel short-circuit was evaluated at different engine operating points. The results will show that also in case of a high pressure injection the best performance can be obtained when a suitable interaction between the liquid jet of fuel and the flow of scavenging air is ensured, as well as with the appropriate choice of the injection timing.
CitationBalduzzi, F., Romani, L., Tanganelli, A., Bigalli, S. et al., "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, https://doi.org/10.4271/2018-32-0040.
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- Gebrehiwot, M. and Van den Bossche, A. , “Electric Vehicle Possibilities Using Low Power and Light Weight Range Extenders,” Proc. of European Electric Vehicle Congress, Brussels, Belgium, Dec. 3-5, 2014.
- Ragg, P.W., McKay, M.L., and Brooks, R.S. , “Direct Fuel Injection by Compressed Gas,” Orbital Engine Company, Patent US4759335A, 1986.
- Nesti, P. , “Two-Stroke Cycle Internal Combustion Engine Using Pneumatically Assisted Direct Fuel Injection,” Piaggio & C.S.p.A., 2002.
- Ambler, M. and Zocchi, A. , “Development of the Aprillia DI-Tech 50,” SAE Technical Paper 2001-01-1781 , 2001, doi:10.4271/2001-01-1781.
- Duret, P., Lavy, J., Venturi, S., and Allen, C. , “SCIP Simplified Direct Injection for Low Emissions Small Two-Stroke Engines,” SAE Technical Paper 1999-01-3289 , 1999, doi:10.4271/1999-01-3289.
- Winkler, F., Oswald, R., Schögl, O., Abis, A. et al. , “Layout and Development of a 300 cm3 High Performance 2S-LPDI Engine,” SAE Technical Paper 2015-32-0832 , 2015.
- Balduzzi, F., Vichi, G., Romani, L., and Ferrara, G. , “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):2015, doi:10.4271/2015-01-1727.
- Romani, L., Vichi, G., Ferrara, G., Balduzzi, F. et al. , “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 , 2015, doi: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. et al. , “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, doi:10.1016/j.egypro.2017.08.251.
- Jajcevic, D., Almbauer, R., Schmidt, S., Glinsner, K. et al. , “CFD Study of Spray Design for a GDI High Performance 2-Stroke Engine,” SAE Technical Paper 2010-32-0014 , 2010, doi:10.4271/2010-32-0014.
- Winkler, F., Oswald, R., Schoegl, O., and Foxhall, N. , “Characterization of Different Injection Technologies for High Performance Two-Stroke Engines,” SAE Technical Paper 2016-32-0001 , 2016, doi:10.4271/2016-32-0001.
- Borghi, M., Mattarelli, E., Muscoloni, J., Rinaldini, C.A. et al. , “Design and Experimental Development of a Compact and Efficient Range Extender Engine,” Applied Energy 202:507-526, 2017, doi:10.1016/j.apenergy.2017.05.126.
- Wang, X., Ma, J., and Zhao, H. , “Analysis of Mixture Formation Process in a Two-Stroke Boosted Uniflow Scavenged Direct Injection Gasoline Engine,” International Journal of Engine Research, 2017, doi:10.1177/1468087417736451.
- Romani, L., Balduzzi, F., Bosi, L., and Ferrara, G. , “Experimental Investigation on the Potentiality of a GDI System Applied to a Two-Stroke Engine: Analysis on Pollutant Emission and Fuel Consumption Reduction,” SAE Technical Paper 2018-32-0047, presented at SAE Small Engine Technology Conference & Exhibition, Düsseldorf, Nov. 6-8, 2018.
- Ferrara, G., Bellissima, A., Doveri, M., and Balduzzi, F. , “Development of a Non-Conventional Two Stroke Small Engine for Scooter Applications,” SAE Int. J. Engines 3(2):462-472, 2010, doi:10.4271/2010-32-0016.
- Ferrara, G., Balduzzi, F., and Vichi, G. , “An Innovative Solution for Two-Stroke Engines to Reduce the Short-Circuit Effects,” SAE Technical Paper 2012-01-0180 , 2012, doi:10.4271/2012-01-0180.
- Lefebvre, A.H. , Atomization and Sprays (Boca Raton, FL: Taylor & Francis, 1989).
- Ansys, Inc. , 2017, “Fluent Theory Guide,” release 18.2.