Diagnosis of the gas distribution mechanism by the vibroacoustic

In the article the methodology of application of vibroacoustic diagnostic method is considered on the example of gas distribution mechanism (GDM). Until early 2000, this method was not widely used due to the high cost of diagnostic complexes, the complexity of calibration of the sensors used, the complexity of processing and analysis of diagnostic information. Nowadays, its use has been simplified due to the emergence of inexpensive USB oscilloscopes and highly sensitive vibration sensors. In addition, the possibilities of processing diagnostic data and their presentation have increased significantly. In addition, the car was improved in the field of electronic systems and elements, allowing synchronously to receive the necessary diagnostic signal, and then to analyze the obtained data. Element failures of gas distribution mechanism of engine, in particular valve burnout, failure of their tightness, phase displacement, gap growth or their absence, occur in most vehicles with much lower regulatory or limiting mileage. This is explained by a number of operational factors, such as untimely maintenance, the use of non-recommended oils and fuel materials, violation of thermal and load regimes, etc. In 30-50 % of cases, these factors cause an increase in the gaps in the GDM valves. The studies carried out in the presented material made it possible to establish: when the clearance for the outlet in the outlet valve was 0.35 ± 0.05 mm, the value of the vibration pulse signal was -150-182 mV. The control of the gaps in the GDM valves revealed 14 deviations from the 20 controlled engine cylinders. Any excess of the amplitude of the vibration signal above 182 mV requires adjustment of the gaps or replacement of hydraulic pushers. This method and a set of techniques used to quickly and without disassembly determine the technical state of the engine systems for any intermediate states of the diagnosed objects. This set of diagnostic tools, technological methods and regulatory data allows us to recommend their use in modern trucking enterprises engaged in the operation, repair and maintenance of vehicles.