Effects of Multiple Injection on the Emission reduction and Efficiency Increase of Diesel Engines

In this study, the two-stage fuel injection strategy as an effective method for the simultaneous reduction of soot and nitrogen oxides emissions and also increase engine efficiency is investigated. AVL FIRE software for numerical simulation of combustion is used. The direct injection diesel engine OM355 of the research center of Idem Tabriz is selected as the studied engine. The results of the simulation show that for the two-stage fuel injection, the average temperature and pressure in the combustion chamber are the most when 70% and 30% of the fuel is injected in the first and second stages, respectively. The best performance in terms of reducing the emissions of carbon and nitrogen oxides emissions have been achieved by using a design which 90% and 70% of the fuel is sprayed in the first stage, respectively. Considering the interval of 20 degrees of the crankshaft for the start of the second injection can optimize the combustion process and reduce emissions of the engine.