DEVELOPMENT AND EXPERIMENTAL RESEARCH OF A POWER SUPPLY SYSTEM FOR A AUTOTRACTOR DIESEL ENGINE FOR OPERATION IN GAS-DIESEL MODE ON LIQUEFIED PETROLEUM GAS

Abstract

Modernization and conversion of agricultural machinery to alternative fuels is a key tool for improv-ing its environmental and economic performance. The use of liquefied petroleum gas (LPG) in dual-fuel systems allows for a significant reduction in emissions of harmful substances (CO2, CO, NOx), however, the successful conversion of serial tractor diesel engines with the provision of stable operational characteristics at all load modes remains an unsolved scientific and practical prob-lem. The purpose of the work is to develop methods and techniques for experimental research of a diesel engine in a gasodiesel cycle, which ensures its stable operation at various load-speed modes with different fuel mixture compositions. To implement the tasks set, an original schematic diagram of the gas-diesel engine power supply system with a mechanical device for manual adjustment of the position of the high-pressure fuel pump (HPFP) rail of the UTN-5 type was developed, which made it possible to eliminate the instabil-ity of the standard all-mode regulator. Experimental studies were carried out on a KI-5542 brake running-in stand based on a four-cylinder diesel engine 4F11.0/12.5, additionally equipped with gas cylinder equipment, a panel rotameter LZM-15ZT-4 and an electronic gas flow weight control sys-tem. The tests were performed according to the “loading - unloading” cycle. The least squares meth-od (LSK) was applied to build mathematical models of trends of the main parameters. Graphical and mathematical dependences of hourly fuel consumption (Gg, Gdp) and torque (Mk) on the effective engine power (Ne) were constructed. It was established that the torque demonstrates a clear linear dependence on power. The influence of thermal and fuel inertia in the form of a "load-unload" loop was revealed. It was proved that the maximum intensity of liquid fuel substitution by gas is achieved in the middle power range. During the comparative analysis, at the same power, the maximum degree of diesel fuel substitution by gas was recorded, without the risk of detonation phenomena. For comparison, fuel consumption in a purely diesel mode was studied. The proposed method and the developed experimental setup confirmed their full operability and can be used to remove the characteristics of full load and serial conversion of autotractor engines. The results of research work 0125U000363 are presented in this scientific article.