The study of the performance of a diesel nozzle on mixed fuels with insufficient low-temperature properties

Abstract

Today, the properties of rapeseed oil, affecting the fuel supply processes in a tractor diesel, are density, kinematic and dynamic viscosity, as well as surface tension. The purpose of this research is to expand the limits of the fuel base of tractor diesel engines by using mixed fuels with insufficient low-temperature properties. In this regard, the determination of the optimal composition of mixed fuel for the operation of the fuel supply equipment of tractor diesels is a very urgent task. To solve this problem, theoretical studies were conducted to determine the effect of rapeseed oil additives on the properties of mixed fuels, as well as testing a diesel fuel injector. As a result of the studies, the dependences of the viscosity of the mixed fuel, the pressure of injection beginning, the tightness of the locking cone, and the hydro-density of the spray nozzle on the addition of rapeseed oil with an additive were determined. Based on theoretical calculations, the value of the viscosity of mixed fuel that meets the requirements of the manufacturer's specifications for fuel injectors is obtained. An analysis of the experimental dependences showed that with an increase in the proportion of rapeseed oil in mixed fuel from 0 to 100 %, there increased: the pressure at the beginning of injection from 20,88 to 21,08 MPa, the time until a drop of fuel comes off from the nozzle of the spray from 18 to 104 s, and pressure reduction time decreased from 5,2 to 11,3 s. Tests shown that for all mixed fuel compositions, the injection start pressure, tightness on the locking cone, spray water density and spray needle mobility meet the requirements of GOST 10579-2017, however, the spray quality corresponds to mixed fuel compositions with rapeseed oil up to 60 %. Thus, the use of the proposed fuel compositions will improve the low-temperature properties of mixed fuels with additives of rapeseed oil, and thus expand the fuel base of tractor diesels.