Method for assessing the anti-carbon properties of unmanned aerial vehicle engines

Abstract

At present, the process of design and production of unmanned aerial vehicles has been making progress in Russia, which is caused by the relatively low cost, small size, absence of life hazard to a pilot, stealth, self-sustainability, mobility compared to manned aircraft. At the same time, two-stroke gasoline engines, possessing a higher power-to-volume ratio, unsophisticated design, and lower production costs in comparison with four-stroke gasoline engines, have become widely used in these aircraft. These engines lack a conventional lubrication system, so the oil is supplied to lubricate the cylinder-piston group in the form of a fuel-oil mixture, which burns during the operating procedure together with the fuel. In this case, high-temperature deposits such as carbon and lacquer are accumulated on the parts of the cylinder-piston group. The formation of carbon reduces the engine power, its service life and efficiency, causes an increase in operating costs. One of the solutions to this problem is the use of motor oils with a high level of anti-carbon properties. However, currently a method for assessing the anti-carbon oil properties for unmanned aerial vehicle engines is not available. In accordance with the described chemmotological process, the method was developed, the test equipment (Panel Coking Test Apparatus) was selected and the test modes were established (plate temperature – 290°C, oil temperature in the crankcase – 100°C, spray speed – 800 rev/min, test time – 4 h), allowing you to evaluate and rank motor oils for unmanned aircraft engines based on the anti-carbon properties in the laboratory. As tested, Motul Kart Grand Prix 2T oil has the least tendency for carbonization among tested motor oil samples. Laboratory and bench tests of Novoyl-DD and Motul Kart Grand Prix 2T oils show a high degree of convergence.