Performance and pollutant emission of the reforming-controlled compression ignition engine – Experimental study

The reforming-controlled compression ignition (RefCCI) is an innovative concept integrating the benefits of the low-temperature combustion engine and the High-Pressure Thermochemical Recuperation. This combination enables achieving high thermal efficiency in a wide operating range while mitigating pollutant emissions. This work reports for the first time on results of the RefCCI concept experimental prove and investigation. The experiment findings confirm the results of the previous numerical studies. In addition, new important knowledge was gained on engine performance and emissions dependence on the injection timing of the primary and reformate fuels, as well as on the fuel mixture reactivity. The results show the thermal efficiency improvement by 4–9% (relative) compared to the same engine operation in diesel mode. In the RefCCI mode, the CO emission is lowered with the increase of load, contrary to the trend in the diesel mode. As expected, NO_x and total particle number emissions are significantly lower than with the diesel counterpart. The emission of nucleation mode particles is fairly similar to diesel, but the number of accumulation mode particles is reduced by the order of magnitude.