Friction Characteristics of Polyalkylene Glycol Based Engine Oil Formulations Arup Gangopadhyay, D.G. McWatt, and L.D. Elie Ford Motor Company, Dearborn, MI J. B. Cuthbert, E. D. Hock, and K. Sinha* Dow Chemical Company, Midland, MI * Currently at Chevron Oronite, TX STLE Annual Meeting, Orlando, FL May 19, 2014 This is a DOE Funded work, Award # DE-EE0005388 1
Presentation Outline Introduction PAG formulations Motored Friction Results Valvetrain Piston ring and skirt Full engine Conclusions 2
What are PAG oils Introduction The PAG base-fluids were synthesized from the reaction of ethylene and/or propylene oxide or butylene oxide with alcohol and they could be either capped or uncapped. 3
Introduction Why interested in PAG Oils? Advantages Lower friction because of polar molecules higher fuel economy Clean burning - reduces sludge formation High VI (225 vs. 150), low temp. flow property Good detergency, engine cleanliness Excellent oxidative stability, higher oil drain interval Low volatility, lower oil consumption Low toxicity Currently used as Compressor lubricants Refrigeration lubricants Metalworking fluids Textile lubricants Fire resistant hydraulic fluids Two-cycle engine lubricants Industrial gear oils 4
Technical Challenges Additive system Introduction Current engine oil additive packages are developed for mineral and hydrocarbon base stocks May need to develop new additive components Seal Compatibility Need to be compatible with currently used various seal materials in engines Miscibility with mineral and other PAO synthetic oils / additive components 5
Introduction Objective Explore friction reduction potential of PAG based lubricants 6
Base Oil Description Alcohol 1 initiated random copolymer of ethylene oxide and propylene oxide - Capped Alcohol 1 initiated homopolymer of propylene oxide - Capped Alcohol 2 initiated homopolymer of propylene oxide - Capped Alcohol 1 initiated homopolymer of propylene oxide PAG Based Formulations Fluid ID HTHS @150 C KV 100 C cst KV 40 C cst VI Flash Point 2 Noack 3 wt% cp 1 C Base Fluid E-72 11.00 2.66 5.55 20.26 239 212 Formulated E-72 2.83 5.6 22.49 233 212 10.1 Formulated E-72/15-1 2.68 5.5 20.34 232 >200 Formulated E-72/14-2 2.4 5.06 18.36 229 >200 Base Fluid 19.00 2.3 5.21 19.4 223 250 Formulated E-65/13-3 2.37 5.1 20.01 202 250 7.4 Base Fluid 24-1 2.63 5.99 23.3 223 212 Formulated E-65/15-4 2.66 6.06 25.08 204 >200 Formulated 38.01 2.28 5.19 19.8 214 224 Base Fluid 24-2 2.61 6.02 23.4 224 224 Formulated 5-2 2.6 6.06 24.87 207 >200 Base Fluid 22-1 3.57 8.54 42.15 186 262 Formulated 14-1/22-1 3.58 8.79 46.57 171 262 3.9 Formulated 9-1/22-1 2.56 5.95 29.14 155 >150 Formulated 17-1 2.6 6.27 31.29 156 >200 Alcohol 2 initiated copolymer of propylene oxide and butylene Formulated 8-1 2.6 6.62 35.55 144 >200 oxide Group II mineral oil Commercial GF-5 5W20 2.6 8.6 48 164 PAG Base Oil Types Capped copolymer of EO and PO PO Capped PO PO + BO 7
Experimental Details Motored Valvetrain Friction The camshaft and tappets were broken-in at speed ranges 300-2500 RPM for about 150-200 hours to ensure stable friction at each RPM Test were run at 40C, 80C, and 100C oil temperatures Baseline Oil GF-5, SAE 5W-20 8
Experimental Details Motored Piston Ring/Skirt Friction Floating liner principle Measures both torque to turn the crank shaft and piston ring force Test were run at 40C - 120C oil temperatures Baseline Oil GF-5, SAE 5W-30 9
Experimental Details Motored Engine Friction Used a broken-in engine Measures torque to turn the engine Test were run at 40C - 120C oil temperatures Baseline Oil GF-5, SAE 5W-20 10
Motored Valvetrain Friction Results Oils Vis @ 100C 5W-20 8.6 cst 14-2 5.1 8-1 6.6 PAG Oils 13-3 5.1 15-1 5.5 9-1 5.9 14-1 8.8 17-1 6.3 15-4 6.1 PAG formulations showed up to 56% lower valvetrain friction torque than GF-5 SAE 5W-20 oil 11
Motored Valvetrain Friction Results PAG Oils PAG formulations showed up to 42% lower valvetrain friction torque than GF-5 SAE 5W-20 oil 12
Motored Valvetrain Friction Results Oils Vis @ 40C 5W-20 48 cst 14-2 18.4 8-1 35.6 PAG Oils 13-3 20 15-1 20.3 9-1 29.1 14-1 46.6 17-1 31.3 15-4 25.1 PAG formulations showed up to 36% lower valvetrain friction torque than GF-5 SAE 5W-20 oil 13
Motored Valvetrain Friction Results EO + PO formulations appear to show lower friction than others 14
Motored Valvetrain Friction Results PAG Oils Lower friction of PAG formulations is probably more related to base oil chemistry than lower viscosity 15
Motored Piston Ring/Skirt Friction Results 16
Motored Piston Ring/Skirt Friction Results PAG Oils PAG formulations showed 8-49% lower piston ring friction than 17 GF-5 SAE 5W-20 oil
Motored Piston Ring/Skirt Friction Results Lower friction of PAG formulations is probably more related to base oil chemistry than lower viscosity 18
Motored Piston Ring/Skirt Friction Results PAG Oils Power cylinder friction benefit is primarily at lower speed range 19
Motored Engine Friction Results Test Repeatability 20
Motored Engine Friction Results Engine A PAG oils showed 2-11% friction benefit 21
Motored Engine Friction Results Engine B PAG Oil E-72 showed 3-9% friction benefit 22
Conclusions Compared to GF-5 oils PAG oils showed up to 56% valvetrain friction reduction 49% piston ring and skirt friction reduction 11 % motored engine friction reduction EO/PO derived PAGs appeared to show greater friction reduction than other base oils Friction reduction of PAG oils is more related to base oil chemistry than reduced viscosity 23
Acknowledgement The authors greatly acknowledge DOE funding (Award # DE-EE0005388) for this work 24