Effect of Tumble Strength on Combustion and Exhaust Emissions in a Single-Cylinder, Four-Valve, Spark-Ignition Engine 981044
Direct flame imaging and pressure analysis were applied to the combustion of gasoline and compressed natural gas (CNG) in a single-cylinder, four-valve spark-ignition engine equipped with optical access via quartz windows in the cylinder liner and piston crown. Tests were performed at three engine speed/load conditions and at equivalence ratios of 1.0, 0.9 and 0.8. The four-valve head incorporated two different port geometries, with and without metal sleeves to deflect the intake air flow, in order to investigate the effect of tumble strength on combustion and engine-out emissions of unburned hydrocarbons and NOx. The results showed that sleeving of the intake ports produced a significant increase in IMEP and a reduction in CoV IMEP for both CNG and gasoline, due to the greatly reduced bum duration. Combination of the enhanced tumble induced by the sleeved ports and open valve fuel injection has allowed engine performance with CNG comparable to gasoline but with lower NOx levels and a leaner mixture operating limit.
Citation: Arcoumanis, C., Godwin, S., and Kim, J., "Effect of Tumble Strength on Combustion and Exhaust Emissions in a Single-Cylinder, Four-Valve, Spark-Ignition Engine," SAE Technical Paper 981044, 1998, https://doi.org/10.4271/981044. Download Citation
C. Arcoumanis, S. N. Godwin, J. W. Kim
Imperial College of Science, Technology and Medicine
International Congress & Exposition
SI Engine Combustion-SP-1315, Combustion & Emission Control for SI Engines-PT-121, SAE 1998 Transactions - Journal of Engines-V107-3