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Improvements in motor oil fuel efficiency have been mainly achieved through lower viscosity and usage of friction modifiers. Further reduction in viscosity to below SAE #20 could be useful for improvement of fuel efficiency. JASO gasoline engine tests were conducted with an ultra low viscosity oil containing mineral base stocks that showed minimum drive torque during an engine motoring test. The results showed an increase in viscosity, increase in oil consumption and deterioration of detergency. In order to solve these problems, an ultra low viscosity engine oil formulated by a special synthetic base stock with improved volatility was developed. The results of a High Temperature Oxidation Test showed this synthetic oil to have better performance than the mineral oil.

Nissan has developed a practical and available toroidal continuously variable transmission (T-CVT) for passenger vehicles for the first time in the world. This CVT is applicable to engines having an output of torque larger than 400 N-m and makes it possible to use a lock-up clutch at low vehicle speed, resulting in marked improvements in drivability and fuel economy. The authors have developed the T-CVT fluid, which is in this application, having excellent traction coefficient and sufficient capacity as the transmission fluid. This paper mainly describes the traction coefficient measurement procedure and the performance of the newly developed fluid.

High viscosity index(HVI) petroleum base stock, with excellent temperature-viscosity characteristics, oxidation resistance, and low-evaporation properties, offers advantages as the base stock for high fuel economy engine oils, particularly because of its low-friction properties in the boundary and/or “E.H.L (Elastohydrodynamic Lubrication)” area due to its rheological characteristics. This research evaluated HVI base stock's low-friction properties. Upgrading the oil from 5W-30 to 5W-20 was also investigated. The friction properties of the HVI base stock were measured by a unit friction platform. The results show a 28% reduction in friction coefficient compared with the conventional, solvent refined oil, which is attributable to the high-pressure viscosity of the base oil.