Article

Received 30.10.2025

Revised 01.03.2026

Accepted 26.03.2026

Published 05.04.2026

Retrieved from Vol. 30, No. 1, 2026

Pages 17 -29

Tsiuman, M., & Sadovnyk, I. (2026). Research of energy efficiency indicators of a hybrid electric automotive power unit based on a spark ignition engine. The National Transport University Bulletin, 30(1), 17-29. https://doi.org/10.33744/2308-6645-2026-1-30-17-29

Research of energy efficiency indicators of a hybrid electric automotive power unit based on a spark ignition engine

Mykola Tsiuman Ihor Sadovnyk

The article examined the results of an experimental study on the energy-efficiency indicators of a hybrid electric automotive power unit based on a spark-ignition engine. The purpose of the study was to conduct a comprehensive assessment of the energy efficiency of a hybrid electric automotive power unit based on a spark-ignition engine. The research method involved experimental bench tests of a hybrid electric automotive power unit in defined operating modes to determine the regularities of changes in control parameters of the internal combustion engine, electrical subsystems, fuel economy, and environmental indicators. The experimental study of the hybrid electric automotive power unit identified regularities in energy-efficiency indicators and working-process characteristics depending on the output shaft rotational speed and power. Changes were observed in the speed and load modes of the internal combustion engine, motor generator 1, and motor generator 2, as well as in fuel consumption, the air-fuel equivalence ratio, and the ignition timing of the internal combustion engine. The state of charge of the traction battery, thermal-regime parameters of the air supply, lubrication, cooling, and exhaust systems of the internal combustion engine, motor generator 1, motor generator 2, inverter, and battery, and exhaust pollutant concentrations and their neutralisation efficiency were also analysed. Notably, a nearly direct relationship was found between the rotational speed and load of the internal combustion engine and the overall load mode of the power unit. Controlling the air-fuel mixture composition and ignition timing in all modes ensured high fuel efficiency and low emissions of harmful substances. High energy-efficiency indicators under various operating conditions were achieved due to the electric subsystem of the power unit, which provided optimal control of the speed and load mode of the internal combustion engine

torque; hybrid transmission; operating mode; traction battery state of charge; fuel economy; environmental indicators
  1. Abdelbaky, A.N.F., Babangida, A., Kunya, A.B., & Szemes, P.T. (2025). Development and fuel economy optimization of series-parallel hybrid powertrain for van-style VW crafter vehicle. Energies, 18(14), article number 3688. doi: 10.3390/en18143688.
  2. Bazhynov, O.V., & Kravtsov, M.M. (2023). Determining the quality index of electric and hybrid vehicles. Ukrainian Journal of Civil Engineering and Architecture, 5, 19-26. doi: 10.30838/j.bpsacea.2312.241023.19.989.
  3. Bazhynov, O.V., Bazhynova, T.O., & Kravtsov, M.M. (2018). Fundamentals of effective use of environmentally friendly vehicles. Kharkiv: Panov A.M. Publishing House.
  4. Dvadnenko, V., Dziubenko, O., & Pushkar, O. (2022). Asynchronous motor in a mild hybrid vehicle. Vehicle and Electronics. Innovative Technologies, 22, 47-53. doi: 10.30977/veit.2022.22.0.6.
  5. ISO 15550:2016. (2016). Internal combustion engines – determination and method for the measurement of engine power – general requirements. Retrieved from https://www.iso.org/standard/70030.html.
  6. Kumbar, P. (2020). Impact of hybrid vehicles on fuel economy and emissions: A comprehensive analysis. World Journal of Advanced Research and Reviews, 8(1), 307-319. doi: 10.30574/wjarr.2020.8.1.0347.
  7. Maush, Kh. (2017). Increase of the energy efficiency of vehicles by the use of hybrid technologies. (Doctoral dissertation, Kharkiv National Automobile and Highway University, Kharkiv, Ukraine).
  8. Mustafi, N.N. (2021). An overview of hybrid electric vehicle technology. In G. Kalghatgi, A.K. Agarwal, F. Leach & K. Senecal (Eds.), Engines and fuels for future transport. Energy, environment, and sustainability. Singapore: Springer. doi: 10.1007/978-981-16-8717-4_5.
  9. Pan, Y., Zhong, K., Xie, Y., Pan, M., Guan, W., Li, L., Liu, C., Man, X., Zhang, Z., & Li, M. (2025). A review of hybrid vehicles classification and their energy management strategies: An exploration of the advantages of genetic algorithms. Algorithms, 18(6), article number 354. doi: 10.3390/a18060354.
  10. Regulation (EU) 2019/631 of the European Parliament and of the Council of 17 April 2019 “Setting CO₂ Emission Performance Standards for New Passenger Cars and for New Light Commercial Vehicles, and Repealing Regulations (EC) No 443/2009 and (EU) No 510/2011”. (2019, April). Retrieved from https://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=CELEX:32019R0631.
  11. Regulation No 83 of the Economic Commission for Europe of the United Nations (UNECE) – Uniform Provisions Concerning the Approval of Vehicles with Regard to The Emission of Pollutants According to Engine Fuel Requirements [2015/1038]. (2015, January). Retrieved from https://eur-lex.europa.eu/eli/reg/2015/83/oj/eng.
  12. Rimpas, D., Barkas, D.E., Orfanos, V.A., & Christakis, I. (2025). Decarbonizing the transportation sector: A review on the role of electric vehicles towards the European green deal for the new emission standards. Air, 3(2), article number 10. doi: 10.3390/air3020010.
  13. Rojas-Reinoso, E.V., Anacleto-Fernández, M., Utreras-Alomoto, J., Carranco-Quiñonez, C., & Mata, C. (2024). Comparative study of fuel and greenhouse gas consumption of a hybrid vehicle compared to spark ignition vehicles. World Electric Vehicle Journal, 16(1), article number 4. doi: 10.3390/wevj16010004.
  14. Saju, C., Michael, P.A., & Jarin, T. (2022). Modeling and control of a hybrid electric vehicle to optimize system performance for fuel efficiency. Sustainable Energy Technologies and Assessments, 52, article number 102087. doi: 10.1016/j.seta.2022.102087.
  15. Sakhno, V.P., Bezborodova, H.B., Maiak, M.M., & Sharai, S.M. (2004). Automobiles: Traction-speed characteristics and fuel economy. Kyiv: KVITS Publishing House.
  16. Šarkan, B., Gnap, J., & Kiktová, M. (2019). The importance of hybrid vehicles in urban traffic in terms of environmental impact. The Archives of Automotive Engineering – Archiwum Motoryzacji, 85(3), 115-122. doi: 10.14669/am.vol85.art8.
  17. Sergienko, N., Pavlova, N., Sergienko, A., Lyubarsky, B., Borysenko, A., Kalinin, P., Gubskyi, S., & Dreval, O. (2023). Results of modeling of components and working processes of a hybrid car with an asynchronous motor. Bulletin of the National Technical University «KhPI». Series: Automobile and Tractor Construction, 2, 31-47. doi: 10.20998/2078-6840.2022.2.04.
  18. Smyrnov, O.P. (2016). Scientific and technical basis of increasing the operational efficiency of hybrid vehicles. (Doctoral dissertation, Kharkiv National Automobile and Highway University, Kharkiv, Ukraine).
  19. Sosida, S.V. (2023). Improvement of the fuel economy of the engine with spark ignition when using an alcohol-containing additive to gasoline. (Doctoral dissertation, National Transport University, Kyiv, Ukraine).
  20. Staunton, R.H., Ayers, C.W., Marlino, L.D., Chiasson, J.N., & Burress, B.A. (2006). Evaluation of 2004 Toyota Prius hybrid electric drive system. Oak Ridge, TN: Office of Scientific and Technical Information. doi: 10.2172/890029.
  21. Taymaz, I., & Benli, M. (2014). Emissions and fuel economy for a hybrid vehicle. Fuel, 115, 812-817. doi: 10.1016/j.fuel.2013.04.045.
  22. Tomita, M., Shibata, R., Mizuno, Y., Maeda, H., Murasato, K., Shimura, A., Takayama, T., Nakado, T., & Tomita, Y. (2024). Development of new 2.0-liter plug-in hybrid system for the Toyota Prius. SAE Technical Paper Series, 1, article number 2169. doi: 10.4271/2024-01-2169.
  23. Toyota Motor Europe. (n.d.). Retrieved from https://www.techdoc-toyota.com.
  24. Toyota Motor Sales. (2004). 04 Prius. Retrieved from https://www.auto-brochures.com/makes/Toyota/Prius/Toyota_US%20Prius_2004.pdf.
  25. Wang, Y., Wang, Y., & Ren, G. (2021). A brief introduction to a novel high-efficiency hybrid power system for hybrid electric urban light commercial vehicles. SAE International Journal of Commercial Vehicles, 14(2), 185-191. doi: 10.4271/02-14-02-0014.

https://doi.org/10.33744/2308-6645-2026-1-30-17-29