Abstract：To investigate the generation mechanism of NOx for biodiesel combustion, the contrast test of diesel engine fueled with biodiesel and petrolic
diesel was conducted. The heat release rate based on measured cylinder pressure indicator diagraph was calculated. A NO formation model of Zeldovich mechanism was established based on the real heat release rate and chemical component equilibrium of fuel combustion. The effects of combustion features of heat release moment, bulk gas temperature and oxygen concentration on NO formation were also analyzed to explain the reason of much NOx generation in biodiesel engine. The results show that the bulk gas temperature in cylinder of biodiesel engine is decreased, while the ignition start of biodiesel engine is early to reach the trigger temperature of NO formation. The oxygen concentration at combustion area is high due to the oxygenated property of biodiesel. The NOx emission from biodiesel engine is more than that from diesel engine.
2013, Vol. 34 
