Modification of a fourth generation LPG installation improving the power supply to a spark ignition engine

Abstract

Science and Technology article citation info:(*) Tekst artykułu w polskiej wersji językowej dostępny w elektronicznym wydaniu kwartalnika na stronie www.ein.org.pl IntroductionAn LPG installation, similarly to other fuel supply systems, has its advantages and disadvantages. The primary advantages of this fuels system (mainly, the reduction of operation costs) are well-known among drivers. The disadvantages are not so notable among users, although they are equally or even more important.It has been observed that recently, the intensity of research on fourth generation gas installations has decreased, mainly due to the technological advances in vehicle design (mass introduction of direct fuel injection). Modern combustion engines required the development of new solutions for gas installations, using the fuel in its liquid state (LPLi) [5].The installation of an alternative fuel system usually entails a decrease in the engines usefulness factors (power and torque). This, however, can be alleviated with a well-designed intake system. The heat necessary to change the state of LPG can be obtained from inlet air, thanks to which the temperature of the fuel increases while the temperature of the air is decreasing, contradictory to its density. The engine's volumetric efficiency is therefore improved [11] and, consequently, it produces more power and torque.Injection of any type of fuel (LPG included) entails decreasing its pressure (the pressure of LPG before the injector is higher by approximately 1 bar than the pressure in the engine's inlet line [2]). Expanding fuel draws energy in the form of heat from its nearest surroundings (the outlet nozzle and the air drawn by the engine), which in extreme cases may lead to ice forming on the injector nozzle and cut off the supply of LPG. This situation depends on the geometry of the injector (mainly, the diameter of the outlet nozzle) and the engine's operating parameters. The operating parameters of an engine are determined by the users of the vehicle, its designers may however, through optimization for example, change the geometry of the elements of the fuel supply system, and therefore prevent extensive cooling of injector nozzles [6].A team of scientists in South Korea has indicated that the composition of the fuel-air mixture has a significant influence on the velocity andrzej BorawSki Modification of a fourth generation LPg instaLLation iMProving the Power suPPLy to a sPark ignition engine Modyfikacja instaLacji LPg iv generacji PoPrawiająca jakośćProcesu zasiLania siLnika o zaPłonie iskrowyM*

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