THE RESULTS OF ACCELERATED TESTING OF NOZZLE SPRAY TIPS FOR GLOGGING DURING DIESEL OPERATION ON BIO-OIL FUEL

An alternative motor fuel for diesel engines with mechanically controlled fuel supply is mixed bio-oil fuel (MBOF), which differs from petroleum diesel fuel (DF) by increased values of density, viscosity, flash point and reduced cetane number. It was believed a priori that due to the content of vegetable oil in bio-oil fuel during the operation of diesel tractor on MBOF, this could lead to an intensification of the carbon deposition process on the surfaces of the combustion chamber and to clogging of the nozzle spray tips and, as a result, to a deterioration in the quality of spraying, mixing and ignition. Therefore, there is a need for an experimental assessment of the effect of various types of MBOF on the amount of carbon deposits on the nozzle spray tips. The results of comparative accelerated tests performed on a motor unit with a three-cylinder MMZ-3LD diesel engine according to the method developed at the 25th State Research Institute of Chemical Pathology indicate that, in terms of high-temperature deposits on the surfaces of the nozzle spray tips (the coefficient of clogging of the nozzle spray tips, the mass of carbon deposits on the surface of the hull and the locking needle of the sprayers), MBOF that contains rapeseed oil (RM) with a shelf life of 2 months since the production date, is inferior to commercial petroleum summer DF. When the diesel engine was running on 80% DF-L-K5 + 20% RM MBOF, the clogging coefficient of the nozzle spraye tips increased from 35.26% to 41.46% compared to its operation on DF-L-K5 petroleum fuel. Tests also show that camelina oil with a long shelf life (3.2 years) and used as a supplement to petroleum diesel fuel leads to a more intense formation of high-temperature deposits on the surfaces of nozzle spray tips than that with a short shelf life.