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Role of Viscosity Index Improvers in Fuel Efficient Lubricants. Thomas Schimmel 2007-11-28. Outline. Transmission Fluids Hydraulic Fluids Outlook. Modern transmission fluids are formulated at lower viscosity to reduce viscous drag.
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Role of Viscosity Index Improvers in Fuel Efficient Lubricants Thomas Schimmel 2007-11-28
Outline • Transmission Fluids • Hydraulic Fluids • Outlook 2007-11-28 | Evonik RohMax Additives GmbH | Thomas Schimmel
Modern transmission fluids are formulated at lower viscosity to reduce viscous drag. For passenger cars viscosity at 20 – 50 °C is relevant for governmental consumption tests. High Viscosity Index is needed. To maintain stay-in-gradeclassification it is necessary to use shear-stable VI Improvers. Modern highly efficient transmissions are designed towards enhanced torque capacity and reduced size. Resulting higher operating temperatures have to be considered in formulation development. Fuel efficient transmission fluids 2007-11-28 | Evonik RohMax Additives GmbH | Thomas Schimmel
SAE J306 has been updated for fuel economy and shear stability • Stay-in-grade after shear in KRL 20 hours (CEC L-45-A-99) 2007-11-28 | Evonik RohMax Additives GmbH | Thomas Schimmel
1991 1998 Limits % PAMA VII, medium shear stable 23.4 30.2 < 18.5 % PAO 4 0 23 KV 100 °C, mm²/s 15.5 23.1 <24.0 Brookfield @-40 °C, Pa.s 98 148 <150 % KV 100 °C loss after KRL 20 hr 32 40 KV 100 °C after KRL, mm²/s 10.5 13.8 >13.5 Meets SAE J306 JUL98 Significant Change in SAE 75W-90 2007-11-28 | Evonik RohMax Additives GmbH | Thomas Schimmel
PAO HC Oil Limits % shear stable PAMA VII 30.2 30 % PAO 4 or HC Oil (4.3mm²/s) 18 30 KV 100 °C, mm²/s 16.9 16.9 <18.5 Brookfield @-40 °C, Pa.s 148 125 <150 % KV 100 °C loss after KRL 20 hr 18 18 KV 100 °C after KRL, mm²/s 13.9 13.9 >13.5 Meets SAE J306 JUN2005 More Shear Stable Viscoplex for SAE 75W-90 2007-11-28 | Evonik RohMax Additives GmbH | Thomas Schimmel
Applied Torque: 238 Nm, 2000 rpm 8 SAE 90 7 SAE 75W-90 Torque Loss [Nm] 6 5 4 30 60 90 120 150 Oil Temperature (°C) Efficiency of Gear Oils Monograde SAE 90 and Multigrade SAE 75W-90 based on shear stable PAMA VII 2007-11-28 | Evonik RohMax Additives GmbH | Thomas Schimmel
Benefits of shear stable SAE 75W-90 2007-11-28 | Evonik RohMax Additives GmbH | Thomas Schimmel
Influence of VII and base oil on operating temperature T in °C KV 100 = 13 mm2/s PAO Mineral Oil 130 125 120 PIB 115 Mineral Oil 110 105 100 PAMA 95 90 85 VW PV 1452 2007-11-28 | Evonik RohMax Additives GmbH | Thomas Schimmel
The Optimum Range of Viscosity for Hydraulic Fluids 10000 Cavitation 5000 Poor Flow to Lubricated Areas 1000 Sluggish Operation 500 Low Mechanical Efficiency 100 Viscosity, mm2/s 50 Optimum Range 10 Reduced productivity, Overheating 5 High wear, Reduced equipment life 1 2007-11-28 | Evonik RohMax Additives GmbH | Thomas Schimmel
High VI Fluids have Extended Operating Temperatures 10000 Low VI 1000 High VI 100 50 ISO 46 Kinematic Viscosity [mm²/s] High VI 10 5.0 Low VI 3.0 -40 -20 0 20 40 60 80 100 120 140 Temperature, °C 2007-11-28 | Evonik RohMax Additives GmbH | Thomas Schimmel
Multigrade ISO 46, VI =150 (Relative to HM 46) Use of Shear Stable VIIs Increases Efficiency 20 Shear stable PAMA(KRL Viscosity Loss 13%) 10 Total Efficiency Gain [%] 0 Medium shear stable PAMA(KRL Viscosity Loss 30%) -10 20 40 60 80 100 Temperature [°C] 2007-11-28 | Evonik RohMax Additives GmbH | Thomas Schimmel
Base Oil, nd VII dPAMA I dPAMA II Dispersant PAMA VIIs Increase Film Thickness 100 Ball on disc at 80°C Film Thickness [nm] 10 1 0.001 0.01 0.1 1 10 Speed [m/s] Increased film thickness provides better lubrication at low speed. 2007-11-28 | Evonik RohMax Additives GmbH | Thomas Schimmel
OutlookEffects of higher film thickness • Classical properties of dispersant PAMA • Soot and particle dispersancy • New properties of dispersant PAMA • Reduced friction at mixed lubrication • Reduced wear • Longer pitting lifetime 2007-11-28 | Evonik RohMax Additives GmbH | Thomas Schimmel
Conclusion • Polymethacrylates add ecological benefits to lubricant formulations. • Multi-grade fluids formulated with shear stable PAMA VI Improvers lead to • higher efficiency • lower operating temperatures • PAMA VI Improvers of high shear stability and with dispersant function give new options towards fuel efficient formulation design. 2007-11-28 | Evonik RohMax Additives GmbH | Thomas Schimmel