Development and experimental studies of a light vehicle diesel after treatment system with DOC, DPF and urea SCR

Strict adherence to pollution limits poses a risk to light-duty diesel engines due to challenges in post-treatment procedures, product limitations, and emission criteria. This paper aims to determine the underlying principles for the technological development of an after-treatment technique that incorporates a diesel oxidation catalyst (DOC), catalytic Diesel Particle Filter (DPF), urea injector, and catalytic urea selective reduction (SCR). Implementing this selective catalytic reduction (SCR) technique would greatly enhance the catalyst’s ability to convert NOx by regulating the evaporation of urea and avoiding a decrease in exhaust temperature and mixing efficiencies. Moreover, the uniformity of the NH3 concentration distribution over the catalyst surface is advantageous. This study explored the concept of an electrically evaporated urea-dosing device. The investigation revealed that heated urea had a beneficial effect on improving the elimination of NOx from both continuous and intermittent motor operations before its application to the gas exhaust. The cylindrical urea evaporative heating chamber was equipped with a venturi jet that directed urea vapour down the exhaust drain. The urea solution dosing technique, administered by spraying, was a customised method more advantageous than the conventional liquid dosage system.