Influence of Post Injection on Emission Characteristics of a High-Pressure Common-Rail Diesel Engine Fueled with Biodiesel Blends

Abstract

An experimental study was conducted in a high-pressure common-rail diesel engine fueled with biodiesel-diesel blends (the volume ratio of biodiesel is 20%). Influences of post-injection parameters on gaseous and particulate emissions are studied. The results show that post injection timing has greater influence on particulate emissions of biodiesel engine in comparison with post injection quantity. With the delay of post injection timing, NOX emissions firstly reduce and then increase and again slightly reduce, while particulate emissions initially increase and then decrease and again soar, indicating a trade-off relationship. With the increase of post injection quantity, NOX emissions hardly change except at the low engine load, while particulate emissions increase in general. In order to improve the emission performance comprehensively, the injection parameters have to be recalibrated and split injection strategy has to be reformulated when the diesel engine is fueled with biodiesel blends.