Analysis of Regulated Pollutant Emissions and Aftertreatment Efficiency in a GTDi Engine Using Different SOI Strategies 03-11-03-0025

In order to improve performance and minimize pollutant emissions in gasoline turbocharged direct-injection (GTDi) engines, different injection strategies and technologies are being investigated. The inclusion of exhaust gas recirculation (EGR) and the variation of the start of injection (SOI) are some of these strategies that can influence the air-to-fuel (AF) mixture formation and consequently in the combustion process and pollutant emissions. This article presents a complete study of the engine performance, pollutant emissions and aftertreatment efficiency that produces the SOI variation with a fixed EGR rate in a 4-cylinder, turbocharged, gasoline direct-injection engine with 2.0 L displacement. The equipment used in this study are TSI-EEPS for particle measurement and HORIBA MEXA 1230-PM for soot measurement being HORIBA MEXA 7100-DEGR with a heated line selector the system employed for regulated gaseous emission measurement and aftertreatment evaluation. The experimental results confirm how the use of an adequate SOI strategy is indispensable to obtain low exhaust emissions values and a balance between the different pollutants. There was found a slight reduction in brake specific fuel consumption (BSFC) with the SOI advance. The experiments showed a decrease in CO, a non-sensible variation of THC and an increase in NOx emissions with SOI delay. Additionally, a significant increase in particle emissions was observed with early SOIs. Finally, with the SOI delay the aftertreatment performance revealed an increase in the oxidation of CO and a decrease in the reduction of NOx.