Effective abatement of diesel engine emissions with split injections

Abstract

High fuel efficiency with good fuel economy and low carbon monoxide and hydrocarbon emissions are the essential features that are widely used in light, medium and heavy duty applications. However, high emissions of nitrogen (NOx) oxides and particulate matter (PM) is a major challenge and sometimes perplexing. Researchers have tackled the issues on multi-cylinder engines by adopting the common rail fuel injection systems which employs a multiple injection technique. The present work aims at utilising this for a single cylinder diesel engine. To study its efficacy, a numerical analysis by developing a quasidimensional computational model and coupled with thermodynamic considerations to model heat release rates and emissions of NOx and soot. For this purpose, a computer code was developed in C++ and validated with the experimental results. Then a split technique was incorporated into the model. It is noted that for a case of 75(8)25 retarded to injection timings of 12◦bTDC, 8◦bTDC and 4◦bTDC from 16◦bTDC has resulted in 23.7%, 19.6% and 16.2% in soot emissions from the baseline soot emissions. Split injection of 75(8)25 retarded to injection timings of 12◦bTDC, 8◦bTDC and 4◦bTDC from 16◦bTDC has resulted in 34.3%, 70.8% and 76.2% in NOx emissions from the baseline NOx emissions. With the comparison of conventional techniques of retarded timings and EGR, split strategy was observed to yield better results and it could be emphasised that effective abatement of harmful emissions can be achieved through split injection
technique.