A New Challenge for High Performance Two-Cycle Engine Oils, Part-IV: Biodegradable Engine Oil with Low-Smoke Performance

With increasing interest in environmental protection, it has become important to develop biodegradable oils for two-cycle engine that provide low smoke emissions, good biodegradability and good exhaust system blocking performance in land applications. For studying the effects of oil included in exhaust gas for environment, the biodegradability of unburned oil in exhaust gas from two-cycle engine was investigated. The unburned oils when used the oils blended with mineral oil and/or polybutene showed better biodegradability than the new oils. The unburned ester-based synthetic oils showed about the same biodegradability as new oils probably due to their thermo-oxidative stability. But the ester-based synthetic oils showed better biodegradability after exhausting. The developments of new oil to improve the performance of low smoke emissions, good biodegradability and less exhaust system blocking were tried. In order to facilitate the evaluation, DSC and TGA were examined as screening tests. The thermal property measured with DSC was found to be useful for predicting the smoke property. The weight loss in TGA correlated to the exhaust system blocking property. The developed new oil was formulated with properly selected esters and additives. This oil was satisfied JASO FC performance.