Improvement study of a low heat rejection diesel engine at part load operation in dual fuel mode

Abstract

ABSTRACTDual fuel engines use a wide variety of gaseous fuels efficiently while emitting less smoke and NOx than their diesel counterparts. However, they suffer from poor brake thermal efficiency, and high hydrocarbon and carbon monoxide emissions, particularly at lower loads. The aim of this study is to improve the performance and emission characteristics of a low heat rejection diesel engine operating in dual fuel mode, particularly at part load. In this study, a single-cylinder, four-stroke, water cooled, direct injection diesel engine was modified to dual fuel mode. Liquefied petroleum gas (LPG) as the primary fuel was mixed with air at the intake manifold, compressed, and ignited by a small pilot spray of biodiesel as the secondary fuel. The biodiesel was prepared from palm oil using a simple base catalyst transesterification process. From the experimental results, it was observed that at part load operation,the brake thermal efficiency of coated engine running on dual fuel of LPG and biodiesel was improved by3%.. Hydrocarbon and carbon monoxide emissions were reduced by 12% and 17%, respectively, and also a significant reduction of NOx emission from 9%to14% at entire load spectrum compared to diesel and dual fuel operation in uncoated engine.