DIESEL ENGINES DIAGNOSIS AND IMPROVEMENT OF REPAIR AND OPERATION

Abstract

Introduction. In the practice of operating and repairing locomotive diesel engines there are cases when a diesel engine is put into operation after repair works with a set of defects of the high-pressure fuel equipment, the cylinder-piston group and the valve timing gear, and rather large uneven distribution of power over the cylinders which has not been fully remedied. It is known that during operation, especially in conditions of frequent load changes, the number of operational defects increases. Hard-to-detect defects in the fuel equipment, the cylinder-piston group and the valve timing gear lead to an uneven distribution of power over the cylinders, an increase in the overall level vibration, a significant increase in specific fuel consumption and an even greater soot emission and hazardous substances during transient conditions. Moreover, routine maintenance work does not always eliminate all defects on the engine, because, firstly, there is no detailed picture of the defects of the individual components before the repairs and, secondly, there is no parametric testing of the condition of the high-pressure fuel equipment, the cylinder-piston group and the valve timing gear after repair work. Purpose. The task of the effective and reliable diagnostics of the technical condition of the engine components before carrying out repair work to accurately detail the scope of the upcoming repair is crucial as well as the subsequent quality control of the repairs, as a result of which the remaining unresolved defects can be identified. After eliminating defects, it is necessary to evenly distribute the load between the cylinders, which should done by balancing the mean indicated pressure Pi (MIP) with the permissible pressure deviations Pz at the end of compression Pc and exhaust gas temperatures Texh. Results. The research of the working process undertaken by the staff of the Department of Ship Power Plants and Technical Maintenance of Odessa National Maritime University showed that during rheostat tests of K6S310DR diesel engines it is possible to promptly obtain reliable diagnostic information. This is done by using parallel analysis of the pressure-volume diagrams and vibration records of the high-pressure fuel equipment, the cylinder-piston group and the valve timing gear. The spectral analysis of vibroacoustic signals of the gas turbocharger and the analytical method for eliminating the effect of power leakage in the discrete spectrum allows for on-line diagnostics of the oscillation level of the gas turbocharger rotor. Conclusions. These methods, implemented in the DEPAS system developed by the specialists of Odessa National Maritime University, can be effectively used in practice of operating locomotive diesel engines.