Experimental determination of fuel compressibility for diesel engines

Abstract

The expansion of the range of blended fuels offered for use in diesel engines, obtained by additives of vegetable oils to diesel fuel, necessitates the determination of the thermophysical properties of these fuels, which affect the flow of the working process and engine performance. In particular, the fuel supply process is influenced by the amount of fuel compressibility. The compressibility value of mixed fuels with a given component ratio cannot be calculated from known values of this value for diesel fuel and vegetable oils and is determined experimentally. The paper describes a laboratory installation for determining the compressibility of mixed fuels and describes the proposed methodology for conducting experiments and processing their results. The experimental determination of the compressibility value is based on measuring the speed of sound in the fuel. In this study, the speed of sound was determined by recording the propagation of a pressure drop wave in the discharge pipeline when an controlled nozzle was opened. The method of processing the measurement results allows us to obtain a formula linking compressibility with pressure and the composition of the mixed fuel. The operability of the experimental setup and the applicability of the proposed technique is confirmed by comparing the compressibility values found for diesel fuel with known similar data obtained by other researchers