Research On Exhaust Particle Concentration And Size Distribution Characteristics Of The1.4T GDI Engine

The environment is getting worser and energy is being shorter, gasoline direct injection (GDI) engineis concentrated because of its low emission and fuel consumption. However, the GDI engine’scombustion mode is similar to the desiel engine’s, so the GDI engine emits lots of particles. The articlestudys effection of rotating speed, torque and three way catalytic converter (TWC) to GDI engine’sparticle concentration and size distribution under steady-state condition first, and then studys effecitonof different rotating speed and torque range and TWC to GDI engine’s particle concentration and sizedistribution under transient condition.The experiment result indicates:1.With the increase of rotating speed under small torque, the firstpeak of particle concentration curve first decreases then increases, while the second peak first decreasesthen increases then decreases, the concentration geometric mean diameter (GMD) first increases thendecreases. With the increase of rotating speed under medium torque, the first peak of particleconcentration curve first decreases then increases, while the second peak increases, the concentrationGMD first decreases then increases then decreases. With the increase of rotating speed under largetorque, the first peak of particle concentration curve first decreases then increases, while the second peakfirst decreases then increases, the concentration GMD first increases then decreases.2.With the increaseof torque under low rotating speed, the concentration of nucleation and that of accumulation particleboth first increase then decrease, concentration GMD first increase then decrease. With the increase oftorque under medium rotating speed, the concentration of nucleation particle increases then decreases,while the concentration of accumulation particle decreases, concentration GMD first decreases thenincreases then decreases then increases then decreases. With the increase of torque under high rotatingspeed, the concentration of nucleation particle decreases, while the concentration of accumulationparticle first increases then decreases, concentration GMD first increases then decreases then increases.3.As time goes on under low rotating speed and small torque range trancient condition, the peak innucleation area of particle concentration curve first increases then decreases then increases, while theconcentration of accumulation particle increases, concentration GMD first increases then decreases. 4.The variation of particle concentration under medium rotating speed and medium torque rangetrancient condition is similar to that under high rotating speed and large torque range trancient condition,the particle concentration increases as time goes on except the beginning.5.The catalytic efficiency ofTWC on particle first decreases then increases with the increase of diameter and minimizes at120nmdiameter. The catalytic efficiency on nucleation and accumulation particle is60%~70%each.6.Theconcentration of HC, CO, NOx and nucleation and accumulation particle and fuel consumption areclosely related to λ value, temperature and gas flow in the cylinder.The research shows the result of exhaust particle experiment on GDI engine, which indicates therelationship between exhaust particle of GDI engine and human health more accurately. Furthermore,the article supports the research on particle controlling method and formulation of emission regulation.