The effect of reformer gas mixture on the performance and emissions of an HSDI diesel engine

Exhaust analysis and performance calculation was carried out and compared to a neat diesel operation. Introduction of syngas + N2 gas mixture resulted in simultaneous reduction of the formation of NOx and smoke emissions over a broad range of the engine operating window. Estimation of the bottled carbon monoxide utilisation showed that by increasing either the load or the speed the admitted carbon monoxide is utilised more efficiently. As a general rule, CO2 emissions increase when the bottled carbon monoxide utilisation is approximately over 88%. Isolation of the H2 and N2 effect revealed that a CO diluted flame promotes the formation of smoke. When the intake air is enriched with syngas + N2, an increase of engine speed results in reduction of maximum pressure rise rate (dp/da). The effect of load on dp/da varies depending on engine speed. Finally, the engine is more fuel efficient when running on neat diesel.