Abstract: Soot emission mass distributions and particle size distributions in diesel engines were simulated using
an improved soot model. The soot emission mass was measured in a single cylinder diesel engine using a low
pressure impactor (LPI). The model was developed based on an existing detailed soot model with the following
three improvements, using n-tetradecane as fuel instead of n-heptane, coupling “shell” auto-ignition model with
other models in KIVA-3V, and in the multi-steps soot model, considering PAHs (polycyclic aromatic hydrocarbons)
direct deposition at the soot particle surface. The results show that PAHs deposition makes great contributions to
increase soot particle mass with soot particle size determined by the development of PAHs in different stages and
that the soot particle formation change trend by simulation is consistent with that by measurement. Therefore, the
improved soot model can preferably predict the change trend of soot particles generation characteristics.

Key words: diesel engine;, soot particle, size distribution, soot detail model, low pressure impactor (LPI) measure