Reformed Fuel Substitution for Transient Peak Soot Reduction

Advancements in catalytic reforming have demonstrated the ability to generate syngas (a mixture of CO and hydrogen) from a single hydrocarbon stream. This syngas mixture can then be used to replace diesel fuel and enable dual-fuel combustion strategies. The role of port-fuel injected syngas, comprised of equal parts hydrogen and carbon monoxide by volume was investigated experimentally for soot reduction benefits under a transient load change at constant speed. The syngas used for the experiments was presumed to be formed via a partial oxidation on-board fuel reforming process and delivered through gaseous injectors using a custom gas rail supplied with bottle gas, mounted in the swirl runner of the intake manifold. Time-based ramping of the direct-injected fuel with constant syngas fuel mass delivery from 2 to 8 bar brake mean effective pressure was performed on a multi-cylinder, turbocharged, light-duty engine to determine the effects of syngas on transient soot emissions. A Cambustion fNOx400 high-speed emissions analyzer and an AVL 439 opacimeter were used to quantify emissions under the load change to provide sub-cycle and cycle resolved resolution, respectively. Results show substantial soot reduction benefits with modest levels of syngas without significant increases in NOx emissions under the chosen conditions.