This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
Electrical Contact Resistance Measurements. Part I. Temperature Effects on Antiwear Film Formation by Secondary, Primary, and Aryl Zinc Dithiophosphates in Fully Formulated Engine Oil
Technical Paper
2003-01-1971
ISSN: 0148-7191, e-ISSN: 2688-3627
Annotation ability available
Sector:
Language:
English
Abstract
Modern Passenger Car Motor Oils (PCMOs) are formulated to provide superior wear, oxidation, and deposit control under the most demanding driving conditions. In most PCMOs, zinc dialkyldithiophosphate (ZnDTP) has been the dominant antiwear and antioxidant agent for well over 50 years. Unfortunately, the phosphorus in ZnDTP may partially deactivate the exhaust emission catalyst. To ensure that the catalysts function for at least 120,000 miles, engine manufacturers are exploring phosphorus limitations for upcoming PCMO performance categories.
This paper explores the antiwear film formation of low phosphorus engine oils using the Electrical Contact Resistance bench test. A prototype ILSAC GF-4 formulation blended with varying amounts and types of ZnDTP was tested at temperatures typical of operating engines. Secondary ZnDTP was found to produce the best films under the broadest temperature range. As the concentration of phosphorus derived from secondary ZnDTP was reduced from 0.1 wt % to 0.08 wt %, the antiwear film became unstable, sometimes forming and sometimes not. At 0.05 wt % and less phosphorus, no effective antiwear film formed.
In similar experiments with primary and aryl ZnDTP, no effective antiwear film formed at any phosphorus level up to the currently allowable 0.1 wt %.
Recommended Content
Authors
Citation
Roby, S., Yamaguchi, E., Francisco, M., and Ruelas, S., "Electrical Contact Resistance Measurements. Part I. Temperature Effects on Antiwear Film Formation by Secondary, Primary, and Aryl Zinc Dithiophosphates in Fully Formulated Engine Oil," SAE Technical Paper 2003-01-1971, 2003, https://doi.org/10.4271/2003-01-1971.Also In
References
- Roby, S.H. Abraham, W.D. Blalock, K.D. Cowling, S.V. Dix, R.W. Jones, R.N. Kornbrekke, R.E. Righi, D.W. “The Effect of Zinc Dialkyldithiophosphate (ZDP) on Valve Train Wear Rates and Mechanisms in the ASTM Sequence VE Engine Dynamometer Test,” “Tribology - Solving Friction and Wear Problems,” 10th International Colloquium January 9-11 1996 3 2275 2283
- Roby, S.H. Blalock, K.D. “Dispersant, Detergent, and Oxidation Inhibitor Effects in Gasoline Engine Lubricant Testing,” “Tribology - Solving Friction and Wear Problems” 10th International Colloquium January 9-11 1996 3 2265 2274
- Roby, S.H. Supp, J.A. “Effects of Ashless Antiwear Agents on Valve Train Wear and Sludge Formation in Gasoline Engine Testing,” Lubrication Engineering 53 12 17 22 1997
- Roby, S.H. Supp, J.A. Blalock, K.D. “Passenger Car Motor Antiwear Agents for the 21st Century,” “Industrial and Automotive Lubrication,” 11th International Colloquium January 13-15 1998 2 1383 1390
- Yamaguchi, E.S. Roby, S.H. Ryason, P.R. Yeh, S.W. “Electrical Contact Bench Wear Testing: Comparison With Engine Test Results,” SAE Paper 2002-01-2674 2002
- Yamaguchi, E.S. Ryason, P.R. Hansen, T.P. “Electrical Contact Resistance Studies on Zinc Dithiophosphates,” Tribology Letters 3 27 33 1997
- Yamaguchi, E.S. Ryason, P.R. Yeh, S.W. Hansen, T.P. “Boundary Film Formation by ZnDTPs and Detergents Using ECR,” Tribology Transactions 41 2 262 272 1998
- Yamaguchi, E.S. Roby, S.H. Francisco, M.M. Ruelas, S.G. Godfrey, D. “Antiwear Film Formation by ZnDTP, Detergent, and Dispersant Components of Passenger Car Motor Oils,” Tribology Transactions 45 3 425 429 2002
- Giasson, S. Palermo, T Buffeteau, T. Desbat, B. Turlet, J.M. “Study of Boundary Film Formation With Overbased Calcium Sulfonate by PM-IRRAS Spectroscopy,” Thin Solid Films 252 111 119 1994
- Palermo, T. Giasson, S. Buffeteau, T. Desbat, B. Turlet, J.M. “Study of Deposit and Friction Films of Overbased Calcium Sulphonate by PM-IRRAS Spectroscopy,” Lubr. Sci. 8 2 119 127 1996
- Kapsa, Ph. Martin, J.M. Blanc, C. Georges, J.M. “Antiwear Mechanism of ZDDP in the Presence of Calcium Sulfonate Detergent,” Jour. of Lubr. Tech. 103 4 486 496 1981
- Georges, J.M. Martin, J.M. Mathia, T. Kapsa, Ph. Meille, G. Montes, H. “Mechanism of Boundary Lubrication with Zinc Dithiophosphate,” Wear 53 I 9 34 1979
- Georges, J.M. Mazuyer, D. “Pressure Effects on the Shearing of a Colloidal Thin Film,” Jour. Phys. Condens. Matter 3 9545 9550 1991
- Dickert, J.J., Jr. Rowe, C.N Jour. of Organic Chemistry 32 647 653 1967
- Mc Geehan, J.A. Yamaguchi, E.S. Adams, J.Q. “Some Effects of Zinc Dithiophosphates and Detergents on Controlling Engine Wear,” SAE Paper 852133 1985
- Mc Geehan, J.A. Graham, J.P. Yamaguchi, E.S. “Camshaft Surface Temperatures in Fired-Gasoline Engines,” SAE Paper 902162 1990