Design and Assessment of an Exhaust After-Treatment System Equipped with a Fuel

Reaching near-zero cold start emissions in a wide range of ambient conditions is a challenging, yet necessary objective. Optimizing the combustion, although fundamental to lower specific engine-out emissions, is not sufficient, especially in high-performance engines. A very high after-treatment efficiency from engine start-up onwards is mandatory. Active heating technologies allow quick heating up of after-treatment devices like a three way catalyst above their light-off temperature, regardless of engine operation. In this work, the particular characteristics of a fuel burner were analyzed. The steps that led to the design of an exhaust system equipped with a fuel burner are reported. The fuel burner ability to efficiently heat up after-treatment devices was assessed by numerical simulations and then verified experimentally. Cumulative results were compared with a passive catalyst heating strategy. The fuel burner proved effective in reducing tailpipe emissions via pre-heating, i.e. catalyst is heated before engine start.