Tail Pipe Emission Study of an Aged Exhaust after Treatment System for 3.8 Litre Diesel Engine

With implementation of stringent BSVI emission norms and regulations like OBD-II on vehicle, it is essential to define the life of exhaust after treatment along with the vehicle. Diesel after treatment generally consists of DOC, DPF and SCR. Lubricating oil contains phosphorus and zinc which adversely affect the DOC. Unburned hydrocarbons (UNHBC) and SOF in tail pipe get accumulated in the DPF. This requires regeneration process where in, high temperatures in exhaust after treatment (EATS) burn the adsorbed Sulphur or phosphorus, thereby improving the conversion efficiencies. Repeated regenerations lead to ash accumulation in DPF and this reduces its capability for soot accumulation. Sulphur in the exhaust impacts SCR through NOx conversion. The present study analyzes the effect of (1) Chemical aging (2) Thermal aging on 3.77 liter diesel engine after treatment. A test cycle was prepared to run the durability for EATS. It consists of total normal running hours as well as cumulative regeneration hours to analyze both chemical and thermal aging impact on EATS. The results show the impact on DOC in terms of HC slip at DOC out, total ash accumulation in DPF and SCR conversion efficiency, along with NH₃ slip with same dosing level of urea dosing, at different running hours so that the safest life span can be calculated.