In-Cylinder Reduction of PM and NOX Emissions from Diesel Combustion with Advanced Injection Strategies

In-Cylinder Reduction of PM and NOX Emissions from Diesel Combustion with Advanced Injection Strategies

Researchers:
Christos Chryssakis
Zoran Filipi
Dennis Assanis

Sponsors:
Automotive Research Center (TACOM)

Abstract:
Increasingly stringent emissions regulations for diesel engines require the employment of advanced injection strategies in order to reduce in-cylinder Nitrogen Oxide (NOX) and Particulate Matter (PM) emissions. In order to gain further understanding of the combustion and emissions formation mechanisms from multiple injections events, Computational Fluid Dynamics (CFD) analysis is performed to model in-cylinder processes. The modeling work is assisted by experimental investigation on a V-8 International diesel engine.

Main focus of the current study was to explore the mechanisms that can be used towards reducing emissions from diesel combustion. EGR was not used in order to analyze the effect of multiple injections without including any other parameters. Results showed that pilot injections have the potential to reduce both NOX and PM emissions, due to improved fuel-air mixing and due to the fact that the diffusion combustion is reduced. Furthermore, post injection can accelerate the soot oxidation process if the injection timing and the amount of fuel are suitably selected.

Main-Post-Post Injection
CFD result for a Pilot-Main-Post fuel injection strategy