| 摘要 |
The invention pertains to multifunctional lubricating fluids for use in the different assemblies of automotive vehicles, mainly the engine, the transmission or a hydraulic circuit, and relates to a lubricant composition containing at least one oil of the groups I to V and a mixture of at least two polymers having a difference of the permanent shearing stability index (PSSI), as measured by the standardised KRL test for 20 hours at 1000°C, of at least 50, and having a viscosity profile such that: (a) at 1000°C, after a 30 cycle Bosch test following the CEC-L- 14-A-93 standard, the viscosity of the final lubricant composition is higher than 9.0 cSt, preferably in range of 9.0 to 12.0 cSt for a 30 grade starting oil, or the viscosity of the final lubricant composition is higher than 12.0 cSt, preferably in range of 12.0 to 15.0 cSt for a 40 grade starting oil; (b) at 1000°C, after a 20 hour KRL test following the CEC-L-45-A-99 standard, the viscosity of the final lubricant composition is higher than 8.5 cSt, preferably in range of 8.5 to 11.0 cSt for a 30 or 40 grade starting oil; and (c) at 400°C, after a 3 hour KRL test following the CEC-L-45-A-99 standard with a test duration down to 3 hours, the viscosity of the final lubricant composition is lower than 51.0 cSt, preferably in range of 41 to 51 cSt for a 30 or 40 grade starting oil. |
