Experimental studies regarding the thermal operating regime for SCR catalysts of heavy-duty commercial vehicles

Abstract

Abstract SCR, selective catalytic reduction, is the most efficient method for treating nitrogen oxides – one of the main pollutants of internal combustion engines. The SCR system involves the injection of a reductant (the solution AdBlue) in the exhaust gas flow, the reduction of the oxides being achieved in the catalyst’s interior [1,4,6]. The operating limits of the SCR system are given by need to maintain the temperature conditions for the injected solution as well as the catalyst and its internal components (oxygen and temperature sensors, reductant injector) [2]. Overheating the AdBlue injectors may have a major influence for the operation of the SCR system, the deposits of the decomposed solution within the injectors leading to the system’s out of use. Thus, maintaining an optimum thermal regime by cooling the AdBlue injectors becomes a required solution for a good functioning of the entire system. The paper presents experimental studies in relation to the thermal evolution of SCR catalysts on heavy-duty commercial vehicles in different turnover situations as well as an analysis of the measured values.