Abstract
Keywords:
Diesel engines, Premixed combustion, 3D Modelling, Exhaust emissions reduction, Combustion optimisation
Abstract:
A combined computational and experimental study of new injection strategies on Heavy Duty Diesel engines has been performed. These strategies, which include multiple injections with very early SOI, modify the Diesel combustion, and lead to two separate stages: an enhanced premixed combustion phase with HCCI-like characteristics and the diffusiondominated combustion phase of the high temperature combustion. Under these conditions, CFD modelling acquires great relevance in order to analyse in-cylinder phenomena, such as spray behaviour in a low density and temperature environment and injection and combustion phases interactions. CFD modelling by means of the KIVA 3V code with specific Diesel injection and combustion sub-models has been used to analyse the experimental results. This analysis has been mainly focused on the air-fuel mixture formation and distribution and its implications on combustion development. It has been possible to determine the general qualitative trends of the most relevant in-cylinder parameters and confirm some of the most important hypotheses presumed from the experimental measurements.