Research on ultra-high viscosity index engine oil: Part2 - Influence of engine oil evaporation characteristics on oil consumption of internal combustion engines
2022-01-0634
03/29/2022
- Event
- Content
- CO2 emission reduction is one of the most important challenges for automotive industry to prevent the global warming. Friction reduction of internal combustion engines (ICEs) is an effective countermeasure. Engine oil lubricates various engine parts and its improvement can contribute to reduce fuel consumption of ICEs by reducing frictions among engine parts. Electrification of ICE powertrains provides higher overall efficiency and leads to lower average engine oil temperature during vehicle operation. In order to reduce the engine friction, engine oil viscosity reduction at low-mid temperature range is important. The viscosity reduction at low-mid temperature while maintaining high temperature viscosity can be realized by reducing base oil viscosity and adding more Viscosity Modifier (VM) that increases viscosity index effectively (“flat viscosity” concept). On the other hand, reduction of base oil viscosity increases volatility loss and may cause oil consumption increase as a trade-off. ASTM D5800 (NOACK test) has been utilized as an industry standard test since 1930s to measure evaporative loss of engine oils related to evaporative oil consumption. However, there are some reports that indicated the NOACK did not correlate with actual engine oil consumption well. New evaporative index to show better correlation is necessary for further engine oil technology development. In this study, a physical property of engine oil which can show the evaporation rate is investigated. As a result, the modified NOACK test at 150°C which is in the temperature range of cylinder bore showed good correlation to the oil consumption in actual engine operation. Therefore the modified NOACK test has high possibility to be the new evaporative index, and to realize the new concept oil with flat viscosity property.
- Citation
- Koyama, T., Suzuki, T., Yamamori, K., Uematsu, Y. et al., "Research on ultra-high viscosity index engine oil: Part2 - Influence of engine oil evaporation characteristics on oil consumption of internal combustion engines," SAE Technical Paper 2022-01-0634, 2022, .