Turbocharging is a system which increases the air preassure ahead of its entering in the cylinder, that way the cylinder is packed with more air and that leads to the possibility of increased fuel combustion. Impulse turbine and compressor are the two basic parts that form the turbocharger. The result of this procedure is an increased engine power. By using the Lotus Engineering software a numerical simulation was carried out which provided the characteristics of the diesel engine in variations such as free suction, single-turbocharging and sequential turbocharging. In chapter 2, it was explained how the circular cycle with interal combustion works. Chapter 3 described the compositon of an engine with all its parts. Chapter 4 and 5 presented the system upgrade components, turbocharging and cooling. Chapter 6 described the detailed view of the engine model and the conducted analyzes. The last chapter provided the results and data comparison. The highest specific fuel consumption is in the free suction variation, the fuel consumption is lower in the single-turbocharging variation and although the lines almost coincide in the sequential turbocharging and the single-turbocharging variations, the sequential turbcharging requires more fuel consumption. The largest variances exists in power after a engine speed of 3500 rpm in which the sequential turbocharging variation that is, a high-pressure turbocharging then achieves the maximum power at a engine speed of 4000 rpm. At lower speeds, in the single-turbocharging variation the engine develops more power because in sequential turbocharging variation the turbocharger is low-pressure up to 3500 rpm. The sequential turbocharging variation is subjected to optimization in its later use. The inaccuracy of the numerical simulation makes it impossible to determine the accuracy of the data.