A computational study and experiments to investigate the combustion and emission characteristics of a small naturally aspirated diesel engine through changes in combustion chamber geometry, injection parameters and EGR

Abstract

Abstract Investigation of the combustion process in engines for improved fuel economy and emissions is best done by combining experiments and simulations. In the present work both experiments and simulations are conducted considering a naturally aspirated common-rail direct-injection (CRDI) diesel engine. The CFD model is developed based on experiments conducted at two operating points, representing to a 0.9 l, two-cylinder, diesel engine. The developed CFD model is then used to study the effects of different in-cylinder strategies attempted at reducing emissions, without compromising on performance. Previous researches conducted on diesel engine CFD simulations are generally based on large-bore large-capacity single-cylinder engines, and mostly investigated a single operating point. The present study investigates the effects of combustion chamber geometry, injection timing, multiple injections as well as EGR, individually as well as in combination, on NOx and soot emissions, at two different operating points in a small naturally aspirated CRDI diesel engine.