Contribution of Oil Layer Mechanism to the Hydrocarbon Emissions from Spark-Ignition Engines 972892
A research program designed to measure the contribution from fuel absorption in the thin layer of oil, lubricating the cylinder liner, to the total and speciated HC emissions from a spark ignition engine has been performed. The logic of the experiment design was to test the oil layer mechanism via variations in the oil layer thickness (through the lubricant formulations), solubility of the fuel components in the lubricants, and variations in the crankcase gas phase HC concentration (through crankcase purging). A set of preliminary experiments were carried out to determine the solubility and diffusivity of the fuel components in the individual lubricants.
Engine tests showed similar HC emissions among the tested lubricants. No consistent increase was observed with oil viscosity (oil film thickness), contrary to what would be expected if fuel-oil absorption was contributing significantly to engine-out HC. Similarly, no effect of crankcase purging could be observed.
A one dimensional absorption/desorption model was used to interpret the HC emissions data for the different lubricants. Neither the total HC emissions, nor the fuel species emissions, nor the results from the crankcase purging tests support the hypothesis that the oil layer is a significant HC mechanism.
Citation: Linna, J., Målberg, H., Bennett, P., Palmer, P. et al., "Contribution of Oil Layer Mechanism to the Hydrocarbon Emissions from Spark-Ignition Engines," SAE Technical Paper 972892, 1997, https://doi.org/10.4271/972892. Download Citation
Jan-Roger Linna, Henrik Målberg, Paul J. Bennett, Peter J. Palmer, Tian Tian, Wai K. Cheng
Volvo Car Components Corp., Massachusetts Institute of Technology
International Fuels & Lubricants Meeting & Exposition
Emission Control and Fuel Economy for Port and Direct Injected SI Engines-PT-91, Combustion and Emission Formation in SI Engines-SP-1300, SAE 1997 Transactions - Journal of Fuels and Lubricants-V106-4