Integrated Study of Inland-Vessel Diesel Engine Two-Cell SCR Systems With Dynamic References

In this paper, we investigate the integrated study of closed-loop control for two-cell selective catalytic reduction (SCR) systems with application to diesel engine-powered small inland vessels. For two-cell SCR systems, the first catalyst cell is mainly used to reduce the nitrogen oxide (NO
_x
) emissions and the second cell aims to adsorb the ammonia from the first cell. Therefore, the ammonia coverage ratios for the first and second SCR cells may be different, and their values affect both the SCR NO
_x
conversion efficiency and tailpipe ammonia slip. Based on the optimization results, several dynamic ammonia-coverage-ratio reference generators are designed and implemented to online produce the references for the two SCR cells. With the generated references, an adaptive backstepping controller is adopted to control the two-cell SCR system. Experimental tests are carried out based on the US06 test cycle. It infers from the test results that the control performance with the designed dynamic reference generators has certain advantages over the performance with selected constant references and the lumped cases.