Experimental and numerical study of using of LPG on characteristics of dual fuel diesel engine under variable compression ratio

Abstract

In this work, an experimental and numerical investigation are carried out to study the impact of adding Liquefied Petroleum Gas (LPG) on the characteristics of diesel engine. New injection control system (ICS) is designed to manage an LPG injector on intake manifold a singlecylinder diesel engine. The engine test rig is powered with traditional diesel fuel to generate the base line data for comparison. Different conditions of load (0%, 25%, 50%, 75%, and 100%) in terms of brake power with three compression ratios of 14.5, 15.5 and 16.5 at constant engine speed of 1500 rpm. LPG is tested in four rates (5 L/min, 10 L/min, 15 L/min, and 20 L/min). The numerical analysis is performed with the help of Diesel-RK simulation software. The multizone combustion model is adopted. Same operating conditions in the experimental work are followed in the numerical simulation. The obtained results revealed that brake thermal efficiency (BTE) and exhaust temperature are reduced while brake specific fuel consumption (BSFC) is increased as the rate of LPG increased. Inducting LPG with (5,10,15,20) L/min reduced carbon monoxide (CO) by 16.6%, 14.7%, 20.3%, and 18.8% respectively. The maximum reduction in hydrocarbon emission (HC) is 8% at the rate of 15 L/min compared to diesel. The volumetric efficiency and NOx emissions are decreased with the use of LPG. As the compression ratio increases, BTE increases and BSFC decreases because of increasing combustion temperature and pressure which decreases delay period, ignites fuel fast and produces more power in small time. The impact of increasing compression ratio reported significant reduction in, CO, HC while NOx are increased. The experimental findings are compared to the results of the Diesel-RK software, as well as with the results of other researchers and good harmony among them is noticed.