The LPG-diesel fuel dual fuelling effect on diesel engine performance

Abstract

The use of alternative fuels can improve the performance of diesel engine in terms of pollution, [1], [2], [3].Low-carbon fuels [2] can successfully replace conventional fuels in modern engines or in future engines [1]. This may be an efficient method to ameliorate the exhaust emissions for engines of 2050, especially in terms of CO2 reduction, an important issue at the internal combustion engines of automotive fleets. The liquid petroleum gas, [1-5] which has a low carbon content comparative to diesel fuel can be a good solution in terms of fuelling. The paper presents an analysis of the experimental results obtained at the speed of 3900 rev/min for three loads: 40%, 55% and 70% for dual fueling with diesel fuel and LPG. At 40% load, at dual fueling, the brake specific fuel consumption (BSFC) is reduced by a maximum of 3.5% for xc = 8.14 comparative to classic fueling and at higher LPG doses the reduction is 1.88%. At 55% load, the dual fueled engine efficiency is similar to that of the classic engine, but for xc=0.37…0.43 the BSFC is reduced by 0.6%…1.2% compared to xc=0.18…0.32. At 70% load there is a continuous improvement in engine efficiency, the BSFC decreasing at dual fueling, especially at all degrees of substitution greater than xc = 0.2, compared to conventional engine. Generally, at dual fueling, the maximum pressure does not exceed the values recorded for classic fueling. At partial load 40% the NOx decrease with 29% for xc=21,57, by up to 17.7% at a maximum xc at a 55% load and by up to at 22.3% at 70% load. Reduction of HC emission level by up to 52.5% at 40% load, by up to 85.7% at 55% load and by 98.3% at 70% load, respectively. For smoke emission, the opacity level is reduced by up to 67.5%, at 40% load, by 50% at 55% load and by 39.13% at 70% load; the smoke number is reduced by up to 66.6% at 40% load, by 55.5% at 55% load and by up to 45.4% at 70% load. The CO2 emission level is reduced by 9.4% at 40% load, 3.1% at 55% load and 6.58% at 70% load, respectively, for the maximum substitution rate used at each operating regime.