A Study of Visible Smoke Reduction from a Small Two-Stroke Engine Using Various Engine Lubricants

This paper relates the smoke reducing characteristics of two-cycle engine lubricants containing polybutene. Making use of these oils instead of conventional ones, not only smoke but also particulate emissions were reduced, while hydrocarbon concentrations were not affected at all. More than ninety percent of the particulates were unburned lubricant, which account for visible smoke. Diluents such as kerosene and leaner fuel/oil ratios also contributed to the reduction of both smoke and particulates.