Mathematical modeling of the change in injection pressure during the transition to mixed fuel, taking into account dynamic effects, wave processes and fuel compressibility

The relevance of the study is due to the need to adapt standard diesel fuel supply systems to mixed fuels based on diesel fuel and rapeseed oil in conditions of energy transition and decarbonization. Currently, there is no unified method for calculating injection pressure for an arbitrary mixture composition, taking into account rheology, dynamics and wave processes. The methodology is based on the synthesis of thermodynamics, outflow hydrodynamics and wave theory using the Barrus, Gr?nberg-Nissan equations and the linear mixing rule. Verification was performed at the M107-CR bench with FD-22.455.111010-50 nozzle. Results: obtained analytical ratio for calculation of injection pressure; an increase in the injection start pressure by 1.1% (up to 21.28 MPa) with a rapeseed oil content of up to 40% and a deterioration in the spray quality when this value is exceeded were confirmed. The developed model allows predicting the necessary correction of fuel supply parameters in accordance with the requirements of GOST 10579–2017, limiting the share of rapeseed oil to 40%, or purposefully adjusting the pressure. The work contributes to solving the problem of adapting diesel engines to renewable fuels.
EDN: APCFCC, https://elibrary/apcfcc

References

[1] Zhosan A.A., Ryzhov Yu.N., Kurochkin A.A. Comparison of the physical and chemical properties of diesel fuel and rapeseed oil. Vestnik OrelGAU, 2011, no. 4, pp. 72–73. EDN: PTUQTP (in Russ.).

[2] Plotnikov S.A., Kantor P.Ya., Kozlov I.S. Research of motor properties of mixes of diesel fuel with rape seed oil. Trudy NGTU im. R.E. Alekseeva [Transactions of Nizhni Novgorod State Technical University n.a. R.Y. Alexeev], 2018, no. 2, pp. 169–174, doi: https://doi.org/10.46960/1816-210X_2018_2_169 (in Russ.).

[3] Kanaveli I.-P., Atzemi M., Lois E. Predicting the viscosity of diesel/biodiesel blends. Fuel, 2017, vol. 199, pp. 248–263, doi: https://doi.org/10.1016/j.fuel.2017.02.077

[4] Gabitova A.R., Gabitov I.R., Zaripov Z.I. Study of the dynamic viscosity coefficient of rapeseed oil as a basis for biodiesel fuel in a wide range of state parameters. Vestnik Tekhnologicheskogo universiteta [Herald of Technological University], 2015, vol. 18, no. 17, pp. 252–254. EDN: UOSRFF (in Russ.).

[5] Markov V., Sa B., Devyanin S., et al. Numerical analysis of injection and spray characteristics of diesel fuel and rapeseed oil in a diesel engine. Case Stud. Therm. Eng., 2022, vol. 35, art. 102129, doi: https://doi.org/10.1016/j.csite.2022.102129

[6] Sekhar P.C., Gupta S.V.G. Performance testing of biodiesel blends with rapeseed oil focusing on combustion, performance, and emissions analysis. Results Eng., 2025, vol. 27, art. 106459, doi: https://doi.org/10.1016/j.rineng.2025.106459

[7] Rayapureddy S.M., Matijošius J., Rimkus A. Comparison of research data of diesel–biodiesel–isopropanol and diesel–rapeseed oil–isopropanol fuel blends mixed at different proportions on a CI engine. Sustainability, 2021, vol. 13, no. 18, art. 10059, doi: https://doi.org/10.3390/su131810059

[8] Lešnik L., Palomar-Torres A., Torres-Jiménez E. et al. The effect of HDPE and LDPE pyrolytic oils on cavitation formation in a common-rail diesel injector. Fuel, 2022, vol. 330, art. 125581, doi: https://doi.org/10.1016/j.fuel.2022.125581

[9] Payri F., Payri R., Salvador F.J. et al. A contribution to the understanding of cavitation effects in Diesel injector nozzles through a combined experimental and computational investigation. Comput. Fluids, 2012, vol. 58, pp. 88–101, doi: https://doi.org/10.1016/j.compfluid.2012.01.005

[10] Desantes J.M., López J.J., Carreres M. et al. Characterization and prediction of the discharge coefficient of non-cavitating diesel injection nozzles. Fuel, 2016, vol. 184, pp. 371–381, doi: https://doi.org/10.1016/j.fuel.2016.07.026

[11] Kiełczyński P., Ptasznik S., Szalewski M. et al. Thermophysical properties of rapeseed oil methyl esters (RME) at high pressures and various temperatures evaluated by ultrasonic methods. Biomass Bioenergy, 2017, vol. 107, pp. 113–121, doi: https://doi.org/10.1016/j.biombioe.2017.09.015

[12] Ilyushin D.N., Kurapin A.V., Salykin E.A. et al. Experimental determination of fuel compressibility for diesel engines. Avtomobil. Doroga. Infrastruktura, 2025, no. 2. URL: https://www.adi-madi.ru/madi/article/view/1454 (in Russ.).

[13] Grekhov L.V., Arsenov N.A., Salykin E.A. et al. Calculation and correction of the fuel mixture elastic properties values. Izvestiya vysshikh uchebnykh zavedeniy. Mashinostroenie [BMSTU Journal of Mechanical Engineering], 2023, no. 5, pp. 74–89, doi: http://dx.doi.org/10.18698/0536-1044-2023-5-74-89 (in Russ.).

[14] Grekhov L.V., Markov V.A., Arsenov N.A. et al. Determination of the constants of the equation of state for calculating the elastic properties of various engine fuels and technical fluids. Vestn. Mosk. Gos. Tekh. Univ. im. N.E. Baumana, Mashinostr. [Herald of the Bauman Moscow State Tech. Univ., Mechan. Eng.], 2022, no. 4, pp. 108–137, doi: https://doi.org/10.18698/0236-3941-2022-4-108-137 (in Russ.).

[15] Nikolić B.D., Kegl B., Marković S.D. et al. Determining the speed of sound, density and bulk modulus of rapeseed oil, biodiesel and diesel fuel. Therm. Sci., 2012, vol. 16, no. S2, pp. S505–S514, doi: https://doi.org/0354-9836/2012/0354-98361200187N

[16] Kondrasheva N.K., Eremeeva A.M. Production of biodiesel fuel from vegetable raw materials. Zapiski Gornogo instituta [Journal of Mining Institute], 2023, vol. 260, pp. 248–256, doi: https://doi.org/10.31897/PMI.2022.15 (in Russ.).