A device for measuring the lost motion of plungers of a distribution type pump is proposed. The indices of plungers’ lost run of pump sections of the fuel pump ND-22/6 are given. As a result of statistical processing of the obtained data, a correlation was established between the values of the lost motion of plungers of the pump sections. It is proposed to use the plunger’s lost motion values as a diagnostic parameter of the technical state of the distribution-type pumps.

Due to the design features of ND-22 type of distribution pumps, equalization of cycle feed values between high-pressure sections is a rather complicated and time-consuming task, the solution of which is accompanied by repeated changes in the dimensions of the drive links with subsequent multiple metering of feed rates. In order to reduce the labor-intensiveness of adjustment operations and increase the accuracy of their performance, a technique and a device have been proposed, that significantly reduce the laboriousness of adjustment operations to equalize performance values between high-pressure sections, while simultaneously increasing the accuracy of their performance. The regularity of the change in the feed rate of the first section of the pump, the change in the length of the adjusting thrust of the metering drive is revealed. The linearity of the correlation relationship between the length of the adjusting thrust and the performance of the first high pressure section has been established. An equation, describing this relationship, is given. The graphic representation of the relationship between the change in the length of the adjustment thrust and the supply of the pump section allows it to be used as a nomogram for selecting the length of the thrust when a given feed cycle value is set during the adjustment work after repair.

In order to study the significance of the impact of wear on the working surfaces of parts of the intermediate gear assembly on the amount of plunger dead stroke and, therefore, on the cycle feed and advance fuel injection angle, we analyzed the critical positions of the parts of the assembly without the repair of its geometric parameters. In the process, the working surfaces of parts and mates are subject to intensive wear, which leads to an increase in the radial play of the intermediate gear. With the help of the developed device, the intermediate gears of the first and second pump sections of 70 ND-22/6 pumps from among the repair stock were examined at the specialized workshop of OAO “Yantikovskoe RTP”. From an analysis of the results of statistical processing of the backlash values in the nodes under study, it follows that in 75% of pumps the value of the radial play of the intermediate gear exceeds the allowable value for the first pumping section and 72% of the pumps for the second section. The paper proposes a method for determining the radial play of the intermediate gear drive of the plunger rotation drive of the distribution type pump. The design of the device for the in-place determination of the radial play of parts in the nodes of intermediate gears is given. Statistical indicators of the radial play of the intermediate gears of the plunger rotation mechanism were obtained. The percentage of shelf life of distribution type pumps is determined by the parameters of the technical condition of the intermediate gear assemblies. According to the research results, it was proposed to transfer the intermediate gear assemblies of the ND-22/6 pumps to the category of repair kits with their obligatory replacement when replacing pump sections.

The stability of the values of cyclic feeds and the angle of the actual beginning of the fuel supply largely depends on the presence of the injection valve of the fuel pump section and its design features. The valve must reliably separate the discharge line from the pre-plunger space and, within certain limits, ensure the residual pressure in the discharge line between cycles. However, the installation of the valve causes a repeated reflection from the valve of the pressure impulses, that follow from the nozzle and leads to the appearance of additional injections or a sluggish fit of the needle on the sprayer seat. In order to eliminate negative consequences, double-acting injection valves are installed on distribution-type pumps, in which the pressure impulses are extinguished by transferring fuel through an additional non-return valve. The use of double-acting valves with non-return valves on distribution-type pumps ensures reliable unloading of the discharge pipe from the cut-off cavity. One of the main purposes of a non-return valve is to provide the necessary hydraulic density of the coupling pressure valve - non-return valve. Serial pumps are equipped with cross-shaped and round-shaped check valves in cross-section, which are designed to provide the same hydraulic tightness of the coupling pressure valve - non-return valve. In the course of research, the results of which are presented in the work, it was revealed that they have different sealing characteristics. In parallel, the characteristics of a triangular and square check valve in cross section were investigated. As a result of research, it was found that square valves have the best sealing characteristics. In the course of the research, it was also revealed that serial check valves of cruciform and round shapes do not provide their functional interchangeability, since they have different abilities to ensure hydraulic tightness of the interface with the discharge valve - non-return valve. Square-shaped check valves in cross-section are more technological to manufacture.