The research was carried out with the aim of increasing the intensity and pressure of fuel injection in direct-acting fuel supply systems of a diesel engine to improve the quality of its work and reduce consumption. To achieve it, on the basis of theoretical studies, the cam profile of the diesel fuel equipment was modernized using the sinusoidal law of plunger motion. The resulting analytical expression of the sinusoidal law of plunger displacement (from the condition of ensuring its shockless and continuous movement along the cam) makes it possible to calculate the cam profile, which provides an increase in the flow rate and high fuel injection pressure. Taking into account the boundary conditions (based on the overall dimensions of the existing 4UTNI pump) and the permissible level of load on the shaft bearing, the profile, speed and acceleration of the cam were calculated. The manufactured experimental pump with a calculated camshaft of a sinusoidal profile showed good results in comparative tests with the existing standard diesel high-pressure pump D-144. For the improved high-pressure fuel pump, the injection intensity and injection pressure in the nominal mode were 9% higher compared to the standard 4UTNI pump, at a low crankshaft speed, the pressure was 20% higher, and the flow rate was 35%. Increasing the injection rate and fuel injection pressure reduces the pusher lift time. At the same time, the cross-sectional uniformity of fuel supply at a shaft speed of n= 1000 min-1 increases by 1.1%, at n= 200 min-1 - by 18%.