Investigation of the Soot and NO Emission Reduction Mechanism in DI Diesel Engines by Means of Split Injection Strategy

The aim of this paper is to investigate the mechanism of soot and NO emission reduction using split injection in a DI Diesel engine. In this research، split injection strategy was introduced as a useful way to reduce both emissions simultaneously. Investigations have been conducted on a DI Diesel engine manufactured by Motorsazan Tabriz Company. To evaluate the benefits of split injection strategy and to reveal the combustion mechanism، modified three-dimensional CFD code KIVA-3V was used. Results showed that use of split injection with appropriate dwell between injection pulses can be effective in simultaneous emissions reduction. Based on computation results، NO reduction mechanism is as single injection with retarded injection timing. Also it is shown that reduced soot formation is because of the fact that the soot-producing rich regions at the fuel spray head are not replenished by new fuel when the injection is stopped and then restarted. The results showed that by using split injection strategy the amount of soot and NO can be reduced by 33% and 11%، respectively.