Specific features of diesel fuel supply under ultra-high pressure

The cessation of increase of fuel consumption under the injection pressure above 350 MPa is experimentally found. The aim of the work is to describe the causes of the phenomenon and to find its adequate mathematical description. The experimental results are given in the article, which were obtained by passing fuel through an orifice and a diesel injector. Methods for calculating fuel heating and consumption during injection at ultra-high pressures are described. It was found that fuel heating occurs due to several factors, each of which can provide heating up to 50 ... 200 degrees C at pressures of 200 ... 400 MPa. On the one hand, the heating of fuel under ultra-high pressures brings the flow regime in nozzle openings to supercritical due to the decrease of the velocity of sound. On the other hand, the overheated fuel worsens the operation of a high-speed electromagnetic drive and, hence, the quality of engine control. The experience in designing Common Rail systems is still insufficient. There is lack of such an experience for ultra-high pressures. Therefore, the creation of methods of calculating the heating of fuel in the nozzle is very relevant today.