Effects of excess air ratio and spark timing on performance and gaseous pollutant emissions of fuel reforming natural gas engine

The combustion and emission characteristics as well as the economic performance of partial oxidation fuel reforming (POFR) natural gas engines were investigated by adjusting the fuel reforming ratios and the engine load. The performance of the POFR engine with a 12% fuel reforming ratio was compared with that of the original engine. The results showed that the fuel-partial-reforming was effective in reducing the cycle-to-cycle variations over the whole range of the operating conditions. The THC and NOX emissions decreased at almost all operating conditions, but showed different decreasing trends at different loads and equivalence ratios, while the CO emissions increased at all operating conditions. It was found that reducing the advancement of ignition timing of the POFR-engine can further reduce the gaseous pollutant emissions without reducing the economic performance of the engine. In conclusion, blending reforming gas improved the overall performance of the natural gas engine at low to medium load conditions.