Numerical Simulation On High Pressure Common Rail Diesel Engine Uses Biodiesel-diesel Mixed Fuel

With the energy crisis and the environment problem becoming more and more serious,energy conservation and environment protection have become the important problem in combustion motor nowadays,researching for new clean substitute energy has become a problem needed to be solved,biodiesel has become the substitute energy focused by people for its renewable energy sources,calorific value equaled with diesel,green product and environmental production, researching on engine uses biodiesel has practical significance.This article choose a high pressure rail diesel engine YN30 CR as the model machine, researching the combustion and emission characteristic that diesel engine sues diesel biodiesel mixed fuel on the diesel engine. Besides, the article research the influence of fuel injection advanced angle on the performance of biodiesel high pressure rail diesel engine, these researches can provide some thesis basis for the biodiesel using in the high pressure rail diesel engine and the design of the biodiesel high rail diesel engine.Using AVL FIRE software to found the combustion chamber mesh, and divide grid in the combustion chamber mesh of the high pressure rail diesel engine, simulating the combustion process the high pressure rail diesel engine uses B0、B10、B20.the model founded are validated accurate., analyzing the fuel air equivalence ratio、temperature field 、 spray velocity field 、 NOX emission concentration field 、 Soot emission concentration field.the simulation results are as follows: with the increasing of the ratio of the biodiesel,the fuel air equivalence ratio in cylinder decreases. At the crank angle of 721.8°CA, the temperature gradient that the engine uses B0 is wider than the engine uses B10 and B20.When the crank angle get to 723.8°CA, the temperature gradient that the engine uses B10 and B20 are wider,the local temperature that the engine uses B10 and B20 are higher than B0.Before the crank angle getting to 727.8°CA, with the increasing of the ratio of the biodiesel, the spray velocity in cylinder decreases, after the crank angle get to 727.8°CA, the spray velocity that the engine uses B10 and B20 are consistent with the engine uses B0.With the increasing of the ration of the biodiesel,the amount of NOX production increases.The amount of Soot production that the engine uses B10 and B20 are consistent with the engine uses diesel.The fields that a large mount of Soot produces are in the high fuel air equivalence ratio fields in the high temperature fields.Many aspects of performance variety that the B20 high pressure rail diesel engine operations in different fuel injection advanced angles were also analyzed.The results are as follows :in the condition that the engine operations at the speed of 2200r/min, 75% load,with the increasing of the fuel injection advanced angle,the peak value of the heat release rate、the peak of the pressure in cylinder、the accumulated heat release increases, the crank angle of the peak value of the heat release rate and the crank angle of the peak value of the pressure in cylinder advance, the Soot emission decrease,the NOX emission increases.