Numerical design of the diesel particulate filter for optimum thermal performances during regeneration

A minimization of the maximum diesel particulate filter (DPF) wall temperature and fast light-off during regeneration are targets for a high durability of the DPF and a high efficiency of soot regeneration. A one-channel numerical model has been adopted in order to predict the transient thermal response of the DPF. The effect of the ratio of the length to diameter (L/D), cell density, the amount of soot loading on the temporal thermal response and regeneration characteristics have been numerically investigated under two representative running conditions: city driving mode and high speed mode. The results indicated that the maximum wall temperature of the DPF increased with increasing ‘L/D’ in ‘high speed mode’. On the contrary, the maximum wall temperature decreases with increasing ‘L/D’ in the range of ‘L/D ⩾ 0.6’ in ‘city driving mode’. The maximum temperature decreased with increasing cell density because heat conduction and heat capacity were increased. Before commencing soot regeneration, the maximum allowed soot loading for retaining DPF durability was about 140 g (5.03 kg/m3) under ‘city driving mode’ and about 200 g (7.19 kg/m3) under ‘high speed mode’ in this study. The effect of the amount of soot loading on light-off time was negligible.