Vibration analysis of diesel turbocharger for agricultural use

Abstract

Environmental, efficiency and economic requirements for diesel engines are being constantly toughened, thus requiring engine modernization. Increasing the degree of diesel boosting is one of the ways to meet these requirements. However, this leads to an increase of the load on various parts and components of the diesel engine. The turbocharger, as one of the most important engine units, undergoes a high vibration load due to the high rotor speed. As it is known from the practice of the manufacturer, this is one of the most common causes of failure of turbochargers. So the evaluation of the vibration load of the plain bearings in modern turbo-charging units requires careful research, which is the purpose of this work. To measure vibrations in the turbocharger, there was used a three-axis vibration transducer AR81, which was mounted on the turbocharger in such a way that the sensor axes coincided with the axes of the turbocharger. This is necessary to determine both the magnitude of the vibrations, and their direction. According to the measured values of vibration acceleration, it can be concluded that the turbocharger is technically in order, predicted a possible failure and, consequently, taken a decision on the required set of measures or make changes to the design documentation in the case of significant deviations. The study was undertaken in two stages: on a specialized balancing machine and on a gas-dynamic non-motorized bench. During the tests there were detected harmonic and non-harmonic components, resonances associated with an increase in the rotor speed. The values of vibration acceleration along the rotor axis of the turbocharger have been measured, perpendicular to the rotor axis in the horizontal plane, perpendicular to the rotor axis in the vertical plane. According to the results of the experimental data, there have been drawn the conclusions that allow to note the following: to reduce the vibrational loads on the running part of the turbocharger, it is necessary to design the compressor stage in such a way that in all modes of engine operation there would be a substantial margin up to the surging limit; the radial load is significantly higher than the axial load, so the radial bearing must have a significant margin of safety to increase the reliability of the turbocharger.