In the article the paper considers mathematical modeling of fuel equipment of high pressure and regulator of the rotation frequency of the crankshaft of the diesel engine. Analysis of factors affecting fuel equipment, mathematical modelling of the process of fuel into the cylinders, as well as mathematically describes the speed control of the crankshaft of the diesel diesel engine. Joint mathematical model of fuel equipment and rotation speed regulator. Presented algorithm and program calculation process the fuel feed to the cylinders of a diesel engine with a light hydraulic characteristics of generalized elements of fuel equipment and provision of the Executive mechanism of the regulator of the rotation frequency of the crankshaft of the diesel engine. In the work used mathematical and simulation, system analysis methods, the comparative method, methods of theoretical knowledge (formalisation), common logical methods and techniques of research (analysis, synthesis, classification, analogy ).