Improving diagnostics of the cylinder-piston group by pneumatic testing

The task of author’s research was to determine the emerging leaks when compressed air is supplied to the above-piston space under pressure of 4, 5 and 6 kgf / cm2, respectively.

To obtain more reliable results, measurements of the leakage of the above-piston space by pneumatic testing should be performed three times. The deterioration of this tribo-coupling should be assessed by the average values of the obtained values. In order to identify the analytical relationships between the readings of the pneumotester and various types of cylinder malfunctions, it is necessary, to simulate during the experiment the malfunctions most often encountered during ordinary engine operation that affect the tightness of the combustion chamber.

The planned experimental studies were carried out in strict accordance with the tasks and included three stages.

The first stage included the collection and analysis of statistical data on the dependence of engine pneumatic testing indications on various types of cylinder-piston group (CPG) malfunctions during ordinary operation, as well as pneumatic testing of engine cylinders undergoing major repairs and their CPG micrometer size. At the second stage, an experiment to simulate malfunctions on an experimental setup and on a working engine, as well as to determine the influence on the readings of the pneumatic tester of the ratio of leaks in the “piston – ring – sleeve” interface was carried out. The third stage included the processing of statistical data, processing of the data obtained directly during the experiment with the introduced CPG malfunctions and the processing of the data obtained when determining the influence of the leakage ratio in the “piston – ring – sleeve” interface on the readings of the pneumatic tester.