Analysis of the Influence of Diesel Spray Injection on the Ignition and Soot Formation in Multiple Injection Strategy

[EN] Multiple injection strategies have increased their capabilities along with the evolution of injection system technologies up to the point that nowadays it is possible to inject eight different pulses, permitting to improve the engine performance, and consequently, emissions. The present work was realized for two simplified strategies: a pilot-main and a main-post, in order to analyze the influence of an auxiliary pulse on the main and otherwise, in reactive conditions for two pilot/post quantities and four hydraulic dwell times. The study was carried out by employing two optical techniques: diffused back-illumination with flame bandpass chemiluminescence for measuring soot, represented by soot-maps distribution, and single-pass schlieren for ignition delay (ID). Furthermore, a novel methodology for decoupling the start of combustion (SOC) of the second pulse was developed and successfully validated. From the ignition delay results, it was found for all test points that the pilot injection enhanced conditions, which promote a faster ignition of the main pulse, also at higher chamber temperatures, all conditions presented a separate combustion event for each injection. In emission terms, soot increased in the pilot-main strategies compared to its single injection case, as well as, in conditions that promote faster-premixed combustion.This research has been partially funded by Spanish "Ministerio de Ciencia, Innovacion y Universidades" through project RTI2018-099706-B-100. Additionally, the experimental hardware was purchased through FEDER and Generalitat Valenciana under project IDIFEDER/2018/037.Payri, R.; García-Oliver, JM.; Mendoza, V.; Viera, A. (2020). Analysis of the Influence of Diesel Spray Injection on the Ignition and Soot Formation in Multiple Injection Strategy. Energies. 13(13):1-22. https://doi.org/10.3390/en131335051221313Musculus, M. P. B., Miles, P. C., & Pickett, L. M. (2013). Conceptual models for partially premixed low-temperature diesel combustion. Progress in Energy and Combustion Science, 39(2-3), 246-283. doi:10.1016/j.pecs.2012.09.001Han, S., Kim, J., & Bae, C. (2014). Effect of air–fuel mixing quality on characteristics of conventional and low temperature diesel combustion. Applied Energy, 119, 454-466. doi:10.1016/j.apenergy.2013.12.045Mingfa, Y., Hu, W., Zunqing, Z., & Yan, Y. (2009). Experimental Study of Multiple Injections and Coupling Effects of Multi-Injection and EGR in a HD Diesel Engine. SAE Technical Paper Series. doi:10.4271/2009-01-2807Schöppe, D., Stahl, C., Krüger, G., & Dian, V. (2012). Servo-Driven Piezo Common Rail Diesel Injection System. ATZautotechnology, 12(2), 42-47. doi:10.1365/s35595-012-0107-yO’Connor, J., & Musculus, M. (2013). Post Injections for Soot Reduction in Diesel Engines: A Review of Current Understanding. SAE International Journal of Engines, 6(1), 400-421. doi:10.4271/2013-01-0917Samuel J, J., & A, R. (2018). A physics-based model for real-time prediction of ignition delays of multi-pulse fuel injections in direct-injection diesel engines. International Journal of Engine Research, 21(3), 540-558. doi:10.1177/1468087418776876Siebers, D. L., & Higgins, B. (2001). Flame Lift-Off on Direct-Injection Diesel Sprays Under Quiescent Conditions. SAE Technical Paper Series. doi:10.4271/2001-01-0530Benajes, J., Payri, R., Bardi, M., & Martí-Aldaraví, P. (2013). Experimental characterization of diesel ignition and lift-off length using a single-hole ECN injector. Applied Thermal Engineering, 58(1-2), 554-563. doi:10.1016/j.applthermaleng.2013.04.044Payri, R., Salvador, F. J., Manin, J., & Viera, A. (2016). Diesel ignition delay and lift-off length through different methodologies using a multi-hole injector. Applied Energy, 162, 541-550. doi:10.1016/j.apenergy.2015.10.118Higgins, B., Siebers, D. L., & Aradi, A. (2000). Diesel-Spray Ignition and Premixed-Burn Behavior. SAE Technical Paper Series. doi:10.4271/2000-01-0940O’Connor, J., & Musculus, M. (2013). Effects of exhaust gas recirculation and load on soot in a heavy-duty optical diesel engine with close-coupled post injections for high-efficiency combustion phasing. International Journal of Engine Research, 15(4), 421-443. doi:10.1177/1468087413488767Baert, R. S. G., Frijters, P. J. M., Somers, B., Luijten, C. C. M., & de Boer, W. (2009). Design and Operation of a High Pressure, High Temperature Cell for HD Diesel Spray Diagnostics: Guidelines and Results. SAE Technical Paper Series. doi:10.4271/2009-01-0649Payri, R., Gimeno, J., Martí-Aldaraví, P., & Viera, A. (2020). Measurements of the mass allocation for multiple injection strategies using the rate of injection and momentum flux signals. International Journal of Engine Research, 22(4), 1180-1195. doi:10.1177/1468087419894854Payri, R., Salvador, F. J., Abboud, R., & Viera, A. (2020). Study of evaporative diesel spray interaction in multiple injections using optical diagnostics. Applied Thermal Engineering, 176, 115402. doi:10.1016/j.applthermaleng.2020.115402Tschöke, H., & Marohn, R. (Eds.). (2017). 10. Tagung Diesel- und Benzindirekteinspritzung 2016. Proceedings. doi:10.1007/978-3-658-15327-4Payri, R., Bracho, G., Marti-Aldaravi, P., & Viera, A. (2017). Nozzle Geometry Size Influence on Reactive Spray Development: From Spray B to Heavy Duty Applications. SAE Technical Paper Series. doi:10.4271/2017-01-0846Payri, R., Gimeno, J., Cardona, S., & Ayyapureddi, S. (2019). Experimental study of the influence of the fuel and boundary conditions over the soot formation in multi-hole diesel injectors using high-speed color diffused back-illumination technique. Applied Thermal Engineering, 158, 113746. doi:10.1016/j.applthermaleng.2019.113746Meijer, M., Somers, B., Johnson, J., Naber, J., Lee, S.-Y., Malbec, L. M., … Bazyn, T. (2012). ENGINE COMBUSTION NETWORK (ECN): CHARACTERIZATION AND COMPARISON OF BOUNDARY CONDITIONS FOR DIFFERENT COMBUSTION VESSELS. Atomization and Sprays, 22(9), 777-806. doi:10.1615/atomizspr.2012006083Ghandhi, J. B., & Heim, D. M. (2009). An optimized optical system for backlit imaging. Review of Scientific Instruments, 80(5), 056105. doi:10.1063/1.3128728Settles, G. S. (2001). Schlieren and Shadowgraph Techniques. doi:10.1007/978-3-642-56640-0Manin, J., Bardi, M., Pickett, L. M., & Manin, J. (2012). SP2-4 Evaluation of the liquid length via diffused back-illumination imaging in vaporizing diesel sprays(SP: Spray and Spray Combustion,General Session Papers). The Proceedings of the International symposium on diagnostics and modeling of combustion in internal combustion engines, 2012.8(0), 665-673. doi:10.1299/jmsesdm.2012.8.665Payri, R., Salvador, F. J., Bracho, G., & Viera, A. (2017). Differences between single and double-pass schlieren imaging on diesel vapor spray characteristics. Applied Thermal Engineering, 125, 220-231. doi:10.1016/j.applthermaleng.2017.06.140Payri, R., Gimeno, J., Bracho, G., & Vaquerizo, D. (2016). Study of liquid and vapor phase behavior on Diesel sprays for heavy duty engine nozzles. Applied Thermal Engineering, 107, 365-378. doi:10.1016/j.applthermaleng.2016.06.159Pastor, J. V., Payri, R., Garcia-Oliver, J. M., & Nerva, J.-G. (2012). Schlieren Measurements of the ECN-Spray A Penetration under Inert and Reacting Conditions. SAE Technical Paper Series. doi:10.4271/2012-01-0456Siebers, D. L. (1998). Liquid-Phase Fuel Penetration in Diesel Sprays. SAE Technical Paper Series. doi:10.4271/980809Skeen, S. A., Manin, J., Pickett, L. M., Cenker, E., Bruneaux, G., Kondo, K., … Hawkes, E. (2016). A Progress Review on Soot Experiments and Modeling in the Engine Combustion Network (ECN). SAE International Journal of Engines, 9(2), 883-898. doi:10.4271/2016-01-0734Payri, R., García-Oliver, J. M., Xuan, T., & Bardi, M. (2015). A study on diesel spray tip penetration and radial expansion under reacting conditions. Applied Thermal Engineering, 90, 619-629. doi:10.1016/j.applthermaleng.2015.07.042Wu, G., Zhou, X., & Li, T. (2019). Temporal Evolution of Split-Injected Fuel Spray at Elevated Chamber Pressures. Energies, 12(22), 4284. doi:10.3390/en12224284Maes, N., Bakker, P. C., Dam, N., & Somers, B. (2017). Transient Flame Development in a Constant-Volume Vessel Using a Split-Scheme Injection Strategy. SAE International Journal of Fuels and Lubricants, 10(2), 318-327. doi:10.4271/2017-01-0815Park, C., & Busch, S. (2017). The influence of pilot injection on high-temperature ignition processes and early flame structure in a high-speed direct injection diesel engine. International Journal of Engine Research, 19(6), 668-681. doi:10.1177/1468087417728630Kozlov, A., Grinev, V., Terenchenko, A., & Kornilov, G. (2019). An Investigation of the Effect of Fuel Supply Parameters on Combustion Process of the Heavy-Duty Dual-Fuel Diesel Ignited Gas Engine. Energies, 12(12), 2280. doi:10.3390/en12122280Desantes, J. M., García-Oliver, J. M., García, A., & Xuan, T. (2018). Optical study on characteristics of non-reacting and reacting diesel spray with different strategies of split injection. International Journal of Engine Research, 20(6), 606-623. doi:10.1177/1468087418773012Jorques Moreno, C., Stenlaas, O., & Tunestal, P. (2017). Influence of Small Pilot on Main Injection in a Heavy-Duty Diesel Engine. SAE Technical Paper Series. doi:10.4271/2017-01-0708Ameen, M. M., & Abraham, J. (2014). RANS and LES Study of Lift-Off Physics in Reacting Diesel Jets. SAE Technical Paper Series. doi:10.4271/2014-01-1118Pickett, L. M., & Siebers, D. L. (2004). Soot in diesel fuel jets: effects of ambient temperature, ambient density, and injection pressure. Combustion and Flame, 138(1-2), 114-135. doi:10.1016/j.combustflame.2004.04.006Wu, T., Yao, A., Yao, C., Pan, W., Wei, H., Chen, C., & Gao, J. (2018). Effect of diesel late-injection on combustion and emissions characteristics of diesel/methanol dual fuel engine. Fuel, 233, 317-327. doi:10.1016/j.fuel.2018.06.063Peraza, J. E., Payri, R., Gimeno, J., & Bazyn, T. (2017). Spray/wall interaction analysis on an ECN single-hole injector at diesel-like conditions through Schlieren visualization. Proceedings ILASS–Europe 2017. 28th Conference on Liquid Atomization and Spray Systems. doi:10.4995/ilass2017.2017.4709Zhao, L., Torelli, R., Zhu, X., Naber, J., Lee, S.-Y., Som, S., … Raessi, M. (2018). Evaluation of Diesel Spray-Wall Interaction and Morphology around Impingement Location. SAE Technical Paper Series. doi:10.4271/2018-01-027