Análise vibratória em motor agrícola ciclo diesel utilizando diferentes misturas de biocombustíveis

Abstract

The attention of the energy industry has been diverted to the approach of new and renewable fuel sources to replace the use of petroleum derivatives in internal combustion engines. Result of the growing global concern regarding energy insecurity, given the continuous depletion of oil reserves and the evolution of norms to contain pollutant emissions. This demand led to the exploration of new fuels, combined with new fuel injection strategies, contributing to the growth of the biofuels market and increasing the visibility of studies related to this area in recent decades. Although the use of biodiesel in diesel oil mixtures appears to be very positive, there are not many studies related to vibrations for higher percentages. This work aims to evaluate the operational viability of adding biodiesel to the commercial diesel mixture in a turbocharged electronic Diesel cycle engine used in agriculture since the variation and excess vibration can affect the longevity of the machine and the useful life of its components. components. Mixtures of 12% to 30% of biodiesel and commercial Diesel were used, with additions of 3% of biodiesel, and employing a dynamometer of parasitic loads, the engine was tested in the range of 2.000 to 1.100 revolutions per minute. The engine was instrumented with two accelerometers on the X and Y axes to collect combustion vibration signals, positioned on top of the cylinder head, and mechanical vibration signals, located on the side of the engine block, close to the cylinder head. The signal was measured in the time domain, as an acceleration signal and transformed to the frequency domain, where its mean square was later calculated, and the values obtained were compared according to the ISO 20816-1 standard, where it was found that there was an increase in engine vibration as more biodiesel was used in the mixtures, reaching the vibration peak at B30, with 7.09 mm/s, but without exceeding the limits set by the standard. The fuel with the best performance was B15, which presented medium vibration values among the tested fuels, but better performance and specific consumption. Thus, validating the use of higher levels of biodiesel in commercial diesel oil blends.