MEASUREMENTS AND MODELING OF A LEAN BURN GAS-ENGINE

Natural gas is an alternative fuel that has potential for low emission s and a high efficiency. This paper presents the experimental results and predictions om a computer simulation of a fast burn high compressi on ratio (FBHCR) combustion system intended for use in a gas engine. C omparisons are made between the FBHCR combustion system at two compres sion ratios, predictions made by a two-zone combustion model and measu rements from the original combustion system, for the brake efficiency, brake mean effective pressure, maximum cylinder pressure and the brak e specific NOx emissions. Experimental measurements of the unburnt hyd rocarbon emissions, the burn duration and the cycle-by-cycle variation s in combustion are also discussed from the original and fast burn com bustion systems. The results show howl the conflicting aims of low emi ssions and low fuel consumption can be satisfied using a lean burn com bustion system. The computer predictions are shown to be reliable, and thus suitable for estimating the performance of other engine builds.