Exploring the Use of Multiple Injectors and Split Injection to Reduce DI Diesel Engine Emissions

Abstract

This research uses computational modeling to explore methods to increase diesel engine power density while maintaining low pollutant emission levels. Previous experimental studies have shown that injection-rate profiles and injector configurations play important roles on the performance and emissions of particulate and NO x in DI diesel engines. However, there is a lack of systematic studies and fundamental understanding of the mechanisms of spray atomization, mixture formation and distribution, and subsequently, the combustion processes in spray/spray and spray/swirl interaction and flow configurations. In this study, the effects of split injections and multiple injector configurations on diesel engine emissions are investigated numerically using a multi-dimensional computer code. In order to be able to explore the effects of enhanced fuel-air mixing, the use of multiple injectors with different injector locations, spray orientations and impingement angles was studied. The interaction of the spray with the geometry of the combustion chamber was also systematically studied. The potential for the use of multiple injectors to increase engine power density and to significantly reduce particulate and NO x emissions in DI diesel engines is revealed. This work demonstrates that multidimensional modeling can now be used to gain insight into the combustion process and to provide direction for exploring new engine concepts.

Particulate emissions from biodiesel fuelled CI engines

“…Combustion chamber visualization and computational studies on soot formation confirmed that it gets accumulated in the spray tip region [120][121][122][123]. In single injection pulse, high momentum of injected spray droplets for longer duration continuously results in supply of fuel droplets to relatively low temperature regions of the combustion chamber in comparison to split injection case, which results in higher soot formation [120].…”

Diesel Exhaust Emissions and Mitigations

“…These functions are generally enhanced through different injection strategies. Studies have shown that splitting fuel injection into divided doses per combustion cycle reduces emissions [8][9][10][11]. This has enabled injection requirements to be met for different engine operating conditions since engines encounter varying demands, from low-speed, low-load; to medium and high-speed, high-load applications.…”

Combustion-response mapping procedure for internal-combustion engine emissions

“…The pre-integrate approach was applied to model a Caterpillar 3401 direct injection CI diesel engine [41]. The computational meshes for all the modeling cases were created by ICEM-CFD, a mesh generation package with ANSYS.…”