Influence of Engine Oil Evaporation Characteristics on Oil Consumption of Internal Combustion Engines.

Abstract

Reduction of base oil viscosity in engine oils can contribute to further fuel economy improvement of internal combustion engines. On the other hand, the lower viscosity base oil has a concern of oil consumption increase by evaporation. Although NOACK test has been utilized as volatility index related to the oil consumption, it cannot indicate the oil consumption sufficiently. In this study, a physical property of engine oil which can show the evaporation rate is investigated. As a result, saturated vapor pressure in the temperature range of cylinder bore showed good correlation to the oil consumption in actual engine operation.