BACKGROUND: At the present time all worldwide diesel engine manufacturers have directed their development strategies on the way of reduction of harmful emissions, fuel efficiency improving and increasing of the power per liter. Using only accumulator type system is not sufficient for the goals achievement. It is necessary to use new auxiliary units, such as an exhaust catalyst, an exhaust recirculation system, injection of additional liquids together with diesel fuel, as well as to improve the existing units. Increasing the accuracy of injection rate of a nozzle will make it possible to adjust the engine fuel system more precisely, that will have a positive effect on all development directions of diesel engine engineering. Injection rate of a nozzle is dependent on fuel pressure in the nozzle inlet and on control signal timing. Pressure pulsation with stable timing cause irregularity of injection rate of a nozzle. Possibility of decreasing of nozzle inlet pressure pulsation is mainly defined by design of a high-pressure fuel pump, as it supplies fuel partially. The design optimization will make it possible to increase the accuracy of injection rate, that will make a positive effect on development of the diesel engines promising areas. AIMS: Study of irregularity of fuel supply by fuel pumps of various diesel engines designs with the Common Rail fuel accumulation system, aimed to decrease fuel oscillations and to improve stability of injection rate of a nozzle. METHODS: In order to assess the efficiency of high-pressure fuel pump designs, these designs were simulated in the specialised software. Theoretical studies of fuel supply irregularity for various designs of the pumps were carried out. RESULTS: Graphs of non-uniformity of fuel supply of high-pressure pumps depending on their design are obtained. CONCLUSIONS: Based on simulations, the conclusions about design influence on fuel supply irregularity of various designs of pump are made, recommendations for use are given.