STUDY OF THE EFFECT OF FEED PRESSURE AND NOZZLE CHANNEL CROSS-SECTIONS ON FUEL SUPPLY PROCESSES IN GAS-DIESEL LOW-SPEED TWO-STROKE LOW-PRESSURE ENGINES

Abstract

The use of gas fuels for marine two-stroke low-speed internal combustion engines is considered by the International Maritime Organization as the main tool for implementing the program adopted in 2018 to reduce greenhouse gas emissions by half by 2050 compared to 2008. In this regard, the world's leading manufacturers of this type of engines are actively engaged in research and development work aimed at developing, designing, manufacturing and putting them into operation. In this class of engines, there are a number of limitations that do not allow the existing experience of converting four-stroke marine engines to gas fuel to be applied to them. In this regard, each manufacturer develops its own approaches to solving this problem. As a result, two fundamentally different approaches were outlined - this is the supply of gas fuel directly to the working cylinder at the beginning and at the end of the compression stroke. Each of these methods has its own advantages and disadvantages. Earlier, the authors showed that in addition to the already implemented technical solutions, other approaches can be used related to the supply of gas fuel into the working cylinder under a pressure of 4.0...6.0 MPa, which allow combining the advantages of both methods implemented in practice and significantly reduce their inherent disadvantages. In particular, reducing the residence time of the gas-air mixture in the working cylinder of the engine during the compression stroke is an effective method of combating knocking combustion that occurs in low-pressure engines. In turn, this time depends on the pressure under which the gas fuel is supplied to the gas supply module and on the characteristics of its outflow through the flow path of this device. This article is devoted to the study of the influence of the design features of the flow path on the formation of the trajectories of gas fuel movement and the parameters of its outflow from the gas module to the working cylinder under conditions of changing back pressure.