**4. Conclusions**

This research shows an experimental and numerical method to calculate the net forces on the components of an internal combustion engine, including the piston, rod, and crankshaft. The forces reach a maximum value near the top dead center. The force caused by the in-cylinder pressure is the main force affecting the test engine components; however, the friction and inertia also significantly affect these components. These forces strictly depend on the engine speed and the geometrical parameters of these components.

Future research will focus on modeling the thermal dynamic and heat transfer phenomena of the engine to fully evaluate the effect of the deformation of the engine components on the friction forces. In addition, a stress analysis of the piston, rod, and crankshaft will also be conducted to extend the operational lifespan of the engine.

**Author Contributions:** Experimental design was performed by V.N.D. and D.V.N.; fieldwork was conducted by V.N.D.; statistical analyses were performed by D.V.N. and V.N.D. contributed to the writing of the paper.

**Acknowledgments:** This work was supported by the Modelling and Simulation Institute, Viettel Research and Development Institute.

**Conflicts of Interest:** The authors declare no conflict of interest.
