According to the requirements of the selective catalytic reduction (SCR) technology of a high power diesel engine

two schemes of installing and not installing a pre mixer before the injection point were designed. The computational fluid dynamics (CFD) technology was used to simulate the gas-flow trajectory

urea decomposition rate

NH3 distribution uniformity and pressure loss of the two schemes

and the D2 emission cycle test was carried out to verify the NOx conversion efficiency of the two schemes. The simulation and experimental results show that compared to the solution without a pre mixer

the pre-mixer can generate a swirl to promote the full mixing of urea droplets with gas flow

and increase the urea decomposition rate and NH3 distribution uniformity at a higher pressure loss

thereby improving the NOx conversion efficiency of the SCR system

which makes the NOx emissions meet EU Stage V emission regulations

and provides a bright future for the development of higher power diesel engines.