This article presents the research results on technical features and emissions of diesel engines using mechanical fuel systems (R180) when using biodiesel/diesel fuel mixtures with different ratios. The simulation model is built using GT-Suite software, which uses experimental data to calibrate the fire model, and the friction model and compare them with the simulation results. Research results show that the built model gives consistent results with the manufacturer's data and experimental data. When mixing biodiesel with a small ratio (biodiesel rate 10%, B10), the technical performance - emission of the engine changes in a small range. However, if using a mixing ratio of biodiesel 20% (B20), due to changes in fuel composition and properties, it will lead to changes in technical features - emissions of the engine.