The Study of Exhaust Heating to Improve SCR Cold Start Performance

SCR cold-start effects are increasingly important for meeting today's emission requirements [1]. A significant challenge toward quickly achieving NOx abatement is the presence of moisture in the catalyst at lower temperatures [1]. This paper describes the ability of an electric heater to effectively raise the temperature of the exhaust and overcome the effect of moisture and low exhaust temperature, allowing NOx conversion to begin sooner. A model of the moisture storage and removal is presented, along with results from engine tests. Results show that it is possible to achieve high NOx conversion temperatures quickly with robust heater technology that is suited for diesel applications.