RESULTS OF THE TEST OF THE PNEUMATIC LEAKPROOFNESS OF THE CYLINDER-PISTON GROUP OF A DIESEL ENGINE

Reducing the leakproofness of the working volume of the cylinder due to wear of the cylinder piston group or other reasons leads to interruptions in the engine work. (Research purpose) The research purpose is in studying the dependence of the pneumatic leakproofness of the cylinder-piston group of a diesel engine on the position of the piston and the pressure of the air supplied to the cylinder. (Materials and methods) When diagnosing the cylinder-piston group, various devices are used, including pneumatic testers. This test method does not provide reliable information about the reasons for the decrease in air density and since the engine cylinders wear out unevenly, the diagnostic process must be performed at different positions of the piston. (Results and discussion) During the study of pneumatic tightness, it was found that the leakproofness of the worn cylinder-piston group in the zone of the upper dead center at the minimum pressure of the supplied air was 12.8 percent lower than in the rest of the cylinder. With an increase in pressure, the difference in leakproofness decreased to 6.3 percent. Authors confirmed the hypothesis of the dependence of the leakproofness of the worn cylinder-piston group on the position of the piston, which allows us to more accurately determine the cause of the violation of the leakproofness of the cylinder. The low pressure of the supplied air shows a greater informative value of the measurement due to a wider change in the air density in the upper dead center zone compared to the middle part of the cylinder and a smaller change in the density of the air flowing through the gaps of the cylinder-piston group. (Conclusions) In order to increase the degree of accuracy of testing the pneumatic density of the cylinder-piston group, measurements must be carried out several times at different pressures of the supplied air.