Study of the influence of emission control strategies on the soot content and fuel dilution in engine oil

[EN] The engine oil contamination by both particulate matter (PM) and fuel is becoming an important problem since strategies to control pollutant emissions in internal combustion engines (ICE) significantly increase their presence in engine oil. As a consequence, the engine oil loses its tribological properties compromising engine lubrication and leading to potential problems in engine such as wear, corrosion, etc. For that reason, the study of the oil degradation and contamination due to these strategies have a special interest to the engine manufacturers and engine oil formulators. In this paper, the engine oil soot content and fuel dilution is analysed under real engine conditions. The study is addressed from two different but complementary points of views. First, on-line measurements at several engine operating conditions are performed in order to further understand how the soot generation correlates with the oil soot content and other derived problems on oil performance. Then, experimental data available after the experimental campaign is used to calibrate a numerical model, based on Computational Fluid Dynamics (CFD), that estimate the amount of soot particles settled in the engine oil. Results show that soot particles are more present in oil when operating high load-speed conditions and during the Diesel Particulate Filter (DPF) regeneration cycles. Regarding the fuel dilution, delayed post-injections are critical since they significantly increase the amount of fuel in the engine oil. Numerical results also show the relationships between the soot particles generated during combustion and the amount of soot in engine oil, giving an enhanced comprehension of soot-in-oil deposition mechanisms.A. Garcia-Barbera is partially supported through the Programa Nacional de Formation de Recursos Humanos de Investigacion of Spanish Ministerio de Ciencia e Innovation [grant number BES-2016-078073]. The authors also wish to thank Dr. José M. Pastor for his inestimable assistance in the CFD model implementation and data post-processing.Tormos, B.; Novella Rosa, R.; Gómez-Soriano, J.; García-Barberá, A.; Tsuji, N.; Uehara, I.; Alonso, M. (2019). Study of the influence of emission control strategies on the soot content and fuel dilution in engine oil. Tribology International. 136:285-298. https://doi.org/10.1016/j.triboint.2019.03.066285298136Lloyd, A. C., & Cackette, T. A. (2001). Diesel Engines: Environmental Impact and Control. Journal of the Air & Waste Management Association, 51(6), 809-847. doi:10.1080/10473289.2001.10464315Fiebig, M., Wiartalla, A., Holderbaum, B., & Kiesow, S. (2014). Particulate emissions from diesel engines: correlation between engine technology and emissions. Journal of Occupational Medicine and Toxicology, 9(1), 6. doi:10.1186/1745-6673-9-6C. Directive, 91/441/EEC of 26 June 1991 amending Directive 70/220, EEC on the approximation of the laws of the Member States relating to measures to be taken against air pollution by emissions from motor vehicles.E. Regulation, Regulation (EC) No 595/2009 of the European Parliament and of the Council of 18 June 2009 on type-approval of motor vehicles and engines with respect to emissions from heavy duty vehicles (Euro VI) and on access to vehicle repair and maintenance information and amending Regulation (EC) No 715/2007 and Directive 2007/46/EC and repealing Directives 80/1269/EEC, 2005/55/EC and 2005/78/EC, Off J Eur Communities - Legislation 188.Agarwal, D., Singh, S. K., & Agarwal, A. K. (2011). Effect of Exhaust Gas Recirculation (EGR) on performance, emissions, deposits and durability of a constant speed compression ignition engine. Applied Energy, 88(8), 2900-2907. doi:10.1016/j.apenergy.2011.01.066Divekar, P. S., Chen, X., Tjong, J., & Zheng, M. (2016). Energy efficiency impact of EGR on organizing clean combustion in diesel engines. Energy Conversion and Management, 112, 369-381. doi:10.1016/j.enconman.2016.01.042Lattimore, T., Wang, C., Xu, H., Wyszynski, M. L., & Shuai, S. (2016). Investigation of EGR Effect on Combustion and PM Emissions in a DISI Engine. Applied Energy, 161, 256-267. doi:10.1016/j.apenergy.2015.09.080Li, X., Xu, Z., Guan, C., & Huang, Z. (2014). Impact of exhaust gas recirculation (EGR) on soot reactivity from a diesel engine operating at high load. Applied Thermal Engineering, 68(1-2), 100-106. doi:10.1016/j.applthermaleng.2014.04.029Singh, S. K., Agarwal, A. K., & Sharma, M. (2006). Experimental investigations of heavy metal addition in lubricating oil and soot deposition in an EGR operated engine. Applied Thermal Engineering, 26(2-3), 259-266. doi:10.1016/j.applthermaleng.2005.05.004George, S., Balla, S., & Gautam, M. (2007). Effect of diesel soot contaminated oil on engine wear. Wear, 262(9-10), 1113-1122. doi:10.1016/j.wear.2006.11.002Fang, J., Meng, Z., Li, J., Pu, Y., Du, Y., Li, J., … G. Chase, G. (2017). The influence of ash on soot deposition and regeneration processes in diesel particular filter. Applied Thermal Engineering, 124, 633-640. doi:10.1016/j.applthermaleng.2017.06.076Behn, A., Feindt, M., Matz, G., Krause, S., & Gohl, M. (2015). Fuel Transport across the Piston Ring Pack: Measurement System Development and Experiments for Online Fuel Transport and Oil Dilution Measurements. SAE Technical Paper Series. doi:10.4271/2015-24-2535Aldajah, S., Ajayi, O. O., Fenske, G. R., & Goldblatt, I. L. (2007). Effect of exhaust gas recirculation (EGR) contamination of diesel engine oil on wear. Wear, 263(1-6), 93-98. doi:10.1016/j.wear.2006.12.055Dennis, A. J., Garner, C. P., & Taylor, D. H. C. (1999). The Effect of EGR on Diesel Engine Wear. SAE Technical Paper Series. doi:10.4271/1999-01-0839Heredia-Cancino, J. A., Ramezani, M., & Álvarez-Ramos, M. E. (2018). Effect of degradation on tribological performance of engine lubricants at elevated temperatures. Tribology International, 124, 230-237. doi:10.1016/j.triboint.2018.04.015Mc Geehan, J. A., Alexander, W., Ziemer, J. N., Roby, S. H., & Graham, J. P. (1999). The Pivotal Role of Crankcase Oil in Preventing Soot Wear and Extending Filter Life in Low Emission Diesel Engines. SAE Technical Paper Series. doi:10.4271/1999-01-1525Motamen Salehi, F., Morina, A., & Neville, A. (2017). The effect of soot and diesel contamination on wear and friction of engine oil pump. Tribology International, 115, 285-296. doi:10.1016/j.triboint.2017.05.041Lenk, J.-R., Meyer, L., & Provase, I. S. (2014). Oil Dilution Model for Combustion Engines - Detection of Fuel Accumulation and Evaporation. SAE Technical Paper Series. doi:10.4271/2014-36-0170Gautam, M., Chitoor, K., Durbha, M., & Summers, J. C. (1999). Effect of diesel soot contaminated oil on engine wear — investigation of novel oil formulations. Tribology International, 32(12), 687-699. doi:10.1016/s0301-679x(99)00081-xWattrus, M. (2013). Fuel Property Effects on Oil Dilution in Diesel Engines. SAE International Journal of Fuels and Lubricants, 6(3), 794-806. doi:10.4271/2013-01-2680Andreae, M., Fang, H., & Bhandary, K. (2007). Biodiesel and Fuel Dilution of Engine Oil. SAE Technical Paper Series. doi:10.4271/2007-01-4036Antusch, S., Dienwiebel, M., Nold, E., Albers, P., Spicher, U., & Scherge, M. (2010). On the tribochemical action of engine soot. Wear, 269(1-2), 1-12. doi:10.1016/j.wear.2010.02.028Sato, H., Tokuoka, N., Yamamoto, H., & Sasaki, M. (1999). Study on Wear Mechanism by Soot Contaminated in Engine Oil (First Report: Relation Between Characteristics of Used Oil and Wear). SAE Technical Paper Series. doi:10.4271/1999-01-3573Green, D. A., Lewis, R., & Dwyer-Joyce, R. S. (2006). Wear effects and mechanisms of soot-contaminated automotive lubricants. Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology, 220(3), 159-169. doi:10.1243/13506501jet140Tang, Z., Feng, Z., Jin, P., Fu, X., & Chen, H. (2017). The soot handling ability requirements and how to solve soot related viscosity increases of heavy duty diesel engine oil. Industrial Lubrication and Tribology, 69(5), 683-689. doi:10.1108/ilt-02-2015-0024George, S., Balla, S., Gautam, V., & Gautam, M. (2007). Effect of diesel soot on lubricant oil viscosity. Tribology International, 40(5), 809-818. doi:10.1016/j.triboint.2006.08.002Ryason, P. R., Chan, I. Y., & Gilmore, J. T. (1990). Polishing wear by soot. Wear, 137(1), 15-24. doi:10.1016/0043-1648(90)90014-2Broatch, A., Olmeda, P., Margot, X., & Gomez-Soriano, J. (2019). Numerical simulations for evaluating the impact of advanced insulation coatings on H2 additivated gasoline lean combustion in a turbocharged spark-ignited engine. Applied Thermal Engineering, 148, 674-683. doi:10.1016/j.applthermaleng.2018.11.106Broatch, A., Novella, R., García-Tíscar, J., & Gomez-Soriano, J. (2019). On the shift of acoustic characteristics of compression-ignited engines when operating with gasoline partially premixed combustion. Applied Thermal Engineering, 146, 223-231. doi:10.1016/j.applthermaleng.2018.09.089Lapuerta, M., Armas, O., & Hernández, J. J. (1999). Diagnosis of DI Diesel combustion from in-cylinder pressure signal by estimation of mean thermodynamic properties of the gas. Applied Thermal Engineering, 19(5), 513-529. doi:10.1016/s1359-4311(98)00075-1Payri, F., Molina, S., Martín, J., & Armas, O. (2006). Influence of measurement errors and estimated parameters on combustion diagnosis. Applied Thermal Engineering, 26(2-3), 226-236. doi:10.1016/j.applthermaleng.2005.05.006Zhu, X., Zhong, C., & Zhe, J. (2017). Lubricating oil conditioning sensors for online machine health monitoring – A review. Tribology International, 109, 473-484. doi:10.1016/j.triboint.2017.01.015Bredin, A., Larcher, A. V., & Mullins, B. J. (2011). Thermogravimetric analysis of carbon black and engine soot—Towards a more robust oil analysis method. Tribology International, 44(12), 1642-1650. doi:10.1016/j.triboint.2011.06.002Broatch, A., Margot, X., Novella, R., & Gomez-Soriano, J. (2017). Impact of the injector design on the combustion noise of gasoline partially premixed combustion in a 2-stroke engine. Applied Thermal Engineering, 119, 530-540. doi:10.1016/j.applthermaleng.2017.03.081Broatch, A., Novella, R., García-Tíscar, J., & Gomez-Soriano, J. (2018). Potential of dual spray injectors for optimising the noise emission of gasoline partially premixed combustion in a 2-stroke HSDI CI engine. Applied Thermal Engineering, 134, 369-378. doi:10.1016/j.applthermaleng.2018.01.108Yakhot, V., & Orszag, S. A. (1986). Renormalization group analysis of turbulence. I. Basic theory. Journal of Scientific Computing, 1(1), 3-51. doi:10.1007/bf01061452Angelberger, C., Poinsot, T., & Delhay, B. (1997). Improving Near-Wall Combustion and Wall Heat Transfer Modeling in SI Engine Computations. SAE Technical Paper Series. doi:10.4271/972881Issa, R. . (1986). Solution of the implicitly discretised fluid flow equations by operator-splitting. Journal of Computational Physics, 62(1), 40-65. doi:10.1016/0021-9991(86)90099-9Colin, O., & Benkenida, A. (2004). The 3-Zones Extended Coherent Flame Model (Ecfm3z) for Computing Premixed/Diffusion Combustion. Oil & Gas Science and Technology, 59(6), 593-609. doi:10.2516/ogst:2004043K. Huh, A phenomenological model of diesel spray atomization, Proc. of the international conf. on multiphase flows' 91-tsukuba.Reitz, R. D., & Diwakar, R. (1987). Structure of High-Pressure Fuel Sprays. SAE Technical Paper Series. doi:10.4271/870598Habchi, C., Lafossas, F. A., Béard, P., & Broseta, D. (2004). Formulation of a One-Component Fuel Lumping Model to Assess the Effects of Fuel Thermodynamic Properties on Internal Combustion Engine Mixture Preparation and Combustion. SAE Technical Paper Series. doi:10.4271/2004-01-1996Karlsson, A., Magnusson, I., Balthasar, M., & Mauss, F. (1998). Simulation of Soot Formation Under Diesel Engine Conditions Using a Detailed Kinetic Soot Model. SAE Technical Paper Series. doi:10.4271/981022Hiroyasu, H., & Kadota, T. (1976). Models for Combustion and Formation of Nitric Oxide and Soot in Direct Injection Diesel Engines. SAE Technical Paper Series. doi:10.4271/760129Wiedenhoefer, J. F., & Reitz, R. D. (2003). Multidimensional Modeling of the Effects of Radiation and Soot Deposition in Heavy-duty Diesel Engines. SAE Technical Paper Series. doi:10.4271/2003-01-056

Optimization of the Combustion System of a Medium Duty Direct Injection Diesel Engine by Combining CFD modeling with Experimental Validation

The research in the field of internal combustion engines is currently driven by the needs of decreasing fuel consumption and CO2 emissions, while fulfilling the increasingly stringent pollutant emissions regulations. In this framework, this research work focuses on describing a methodology for optimizing the combustion system of compression ignition (CI) engines, by combining computational fluid dynamics (CFD) modeling, and the statistical Design of Experiments (DOE) technique known as Response Surface Method (RSM). As a key aspect, in addition to the definition of the optimum set of values for the input parameters, this methodology is extremely useful to gain knowledge on the cause/effect relationships between the input and output parameters under investigation. This methodology is applied in two sequential studies to the optimization of the combustion system of a 4-cylinder 4-stroke Medium Duty Direct Injection (DI) CI engine, minimizing the fuel consumption while fulfilling the emission limits in terms of NOx and soot. The first study targeted four optimization parameters related to the engine hardware including piston bowl geometry, injector nozzle configuration and mean swirl number (MSN) induced by the intake manifold design. After the analysis of the results, the second study extended to six parameters, limiting the optimization of the engine hardware to the bowl geometry, but including the key air management and injection settings. For both studies, the simulation plans were defined following a Central Composite Design (CCD), providing 25 and 77 simulations respectively. The results confirmed the limited benefits, in terms of fuel consumption, around 2%, with constant NOx emission achieved when optimizing the engine hardware, while keeping air management and injection settings. Thus, including air management and injection settings in the optimization is mandatory to significantly decrease the fuel consumption, by around 5%, while keeping the emission limits.Benajes Calvo, JV.; Novella Rosa, R.; Pastor Enguídanos, JM.; Hernández-López, A.; Hasegawa, M.; Tsuji, N.; Emi, M.... (2016). Optimization of the Combustion System of a Medium Duty Direct Injection Diesel Engine by Combining CFD modeling with Experimental Validation. Energy Conversion and Management. 110:212-229. doi:10.1016/j.enconman.2015.12.010S21222911