Characteristics of Particle Size Distributions About Emissions in A Common-rail Diesel Engine with Biodiesel Blends

Test of particle size distributions are carried out by using the TSI3090 EEPSTM particle size spectrometer and a two- stage dilution system on a high-pressure common rail diesel engine. Analysis of the particle size distributions reveals the physical and chemical characteristics of the biodiesel fuels. The results show that sizes of particle emissions are mostly below 300 nm. Particle size of biodiesel fuel is a bimodal distribution with the number of the nucleation mode accounting for more than 60% of the total particles. With the proportion increase of biodiesel, the number of particles in nucleation mode increases while the accumulation mode particles with a size > 50 nm decreases and the peak area shifts to the small particle size. Particle size distributions of the petroleum diesel show a single peak between 50 ∼ 100 nm region and majority of the particles shows accumulation mode. Engine load has great impact on the particle size distribution, as the load increases the proportion of the nucleation mode decreases.