Performance of Motorcycle Engine Oil with Sulfur-Based Additive as Substitute Zn-DTP 2008-32-0005
Just as CO2 reduction is required of four wheeled vehicles for environmental protection, similar environmental concerns drive the development of motorcycle oil technology.
Zinc dialkyldithiophosphate (Zn-DTP) type additives are widely used for engine oil formulations. However, phosphorus compounds are environmental load materials. The reduction of the quantity of phosphorus compounds in engine oils is required to reduce poisoning of three-way catalysts used to purify exhaust gases from internal combustion engines.
Mr. Ito and his co-authors1) reported that they developed a sulfur-based additive as a substitute for Zn-DTP. Their non-phosphorus engine oil formulation for four-wheeled vehicles with a sulfur-based additive was examined to evaluate its anti-wear performance using the following test methods:JASO M328 for gasoline engines (KA24E) and JASO M354 for Diesel engine (4D34T4).
In this study, a new concept motorcycle engine oil with this sulfur-based additive as a Zn-DTP substitute was examined to see if it met requirements for motorcycle engine oil. The anti-wear performance, antioxidant performance, heat resistance, clutch friction characteristics and engine tests were evaluated.
The candidate oil showed equal or better anti-wear performance, antioxidant performance, heat resistance and clutch friction characteristics compared to that of engine oils containing Zn-DTP.
Additionally, a 600cc motorcycle gasoline engine bench-test was run to evaluate the durability performance of this candidate oil. The better detergency, especially in the piston components and cylinder area, characterized its excellent performance compared to that of a Zn-DTP containing formulation.
The performance data of the candidate oil with sulfur-based additive was reported.