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Determination of Bearing Oil Film Thickness (BOFT) for Various Engine Oils in an Automotive Gasoline Engine Using Capacitance Measurements and Analytical Predictions
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Abstract
Minimum bearing oil film thickness (MBOFT) was measured in both a main and a connecting-rod bearing of a production V-6 engine using the total capacitance method (TCM). MBOFT was measured at 1500 rpm and at three different engine loads (64, 128, and 192 Nm). The oil sump temperature was controlled at 100°C. Five engine oils were tested (SAE grades 5W-20, 20W-20, 5W-30, 10W-30, and 20W-50) with emphasis given to the SAE 5W-30 and 10W-30 oils. MBOFT was also calculated using a computer code.
The absolute minimum of the MBOFT (MBOFTmin, closest approach between the journal and the bearing) increased with increasing values of a Sommerfeld parameter (viscosity/load) and this dependence was similar in both the main and the connecting-rod bearings. But, for the main bearing the MBOFTmin values showed a higher dependence on the Sommerfeld parameter than those for the connecting-rod bearing. Similar results were obtained with the theoretical calculations of the MBOFT_min values.
The experimental data indicated a 10 percent higher MBOFTmin for the SAE 10W-30 oil than for the SAE 5W-30 oil in both bearings. This difference was smaller in the theoretical calculations, about 4 percent for the main and 2 percent for the connecting-rod bearing. Uncertainties in the prediction of the oil viscosity at the high temperatures and pressures of the bearing may have been responsible for this difference.
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Tseregounis, S., Viola, M., and Paranjpe, R., "Determination of Bearing Oil Film Thickness (BOFT) for Various Engine Oils in an Automotive Gasoline Engine Using Capacitance Measurements and Analytical Predictions," SAE Technical Paper 982661, 1998, https://doi.org/10.4271/982661.Also In
References
- Spearot, J.A. Murphy, C.K. “A Comparison of the Total Capacitance and Total Resistance Techniques for Measuring the Thickness of Journal Bearing Oil Films in an Operating Engine” SAE Technical Paper 880680
- Craig, R.C. King, W.H. Appledoorn, J.K. “Oil Film Thickness in Engine Bearings - The Bearing as a Capacitor” SAE Technical Paper 821250
- Bates, T.W. Benwell, S. “Effect of Oil Rheology on Journal Bearing Performance Part 3 --Newtonian Oils in the Connecting-Rod Bearing of an Operating Engine” SAE Technical Paper 880679
- Spearot, J.A. “Relating High-Temperature, High-Shear-Rate Viscosity to Engine Operation” High-Temperature, High-Shear (HTHS) Oil Viscosity: Measurement and Relationship to Engine Operation, ASTM STP 1068 Spearot James American Society of Testing and Materials Philadelphia 1989
- Bates, T.W. Williamson, B.P. Spearot, J.A. Murphy, C.K. “A Correlation Between Engine Oil Rheology and Oil Film Thickness in Engine Journal Bearings” SAE Technical Paper 860376
- Deysarkar, A.K. “The Bearing Oil Film Thickness of Single and Multi-Grade Oils - Part 1: Experimental results in a 3.8L Engine” SAE Technical Paper 880681
- Girshick, F. Craig, R.C. “Oil Film Thickness in a Bearing of a Fired Engine Part III: The Effects of Lubricant Rheology” SAE Technical Paper 831691
- Bates, T.W. Fantino, B. Launay, L. Frêne, J. “Oil Film Thickness in an Elastic Connecting-Rod Bearing Comparison Between Theory and Experiment” SAE Technical Paper 880679
- Choi, J-K Lee, J-H Han D-C “Oil Film Thickness in Engine Main Bearings: Comparison Between Calculation and Experiment by Total Capacitance Method” SAE Technical Paper 922345
- Choi, J-K Hur, H. Han D-C “Oil Film Thickness in Engine Connecting-Rod Bearing: Comparison Between Calculation and Experiment” SAE Technical Paper 930694
- Goenka, P.K. Paranjpe, R.S. Jeng, Y.R. “FLARE: An Integrated Software Package for Friction and Lubrication Analysis of Automotive Engines - Part I: Overview and Applications” SAE Technical Paper 920487
- Goenka, P.K. Paranjpe, R.S. “A Review of Engine Bearing Analysis Methods at General Motors” SAE Technical Paper 920489
- Paranjpe, R.S. “A Study of Dynamically Loaded Engine Bearings Using a Transient Thermohydrodynamic Analysis” Tribology Transactions 39 636 644 1996
- Paranjpe, R.S. Tseregounis, S.I. Viola, M.B. “Comparison between Analytical Predictions and Oil Film Thickness Measurements Using the Total Capacitance Method for Crankshaft Bearings in a Firing Engine” STLE 1999
- Tseregounis, S.I. McMillan, M.L. “Engine Oil Effects on Fuel Economy in GM Vehicles - Comparison with the ASTM Sequence VI-A Engine Dynamometer Test” SAE Technical Paper 952347
- Wright, B. van Os, N.M. Lyons, J.A. “European Activity Concerning Engine Oil Viscosity Classification - Part IV - The Effects of Shear Rate and Temperature on the Viscosity of Multigrade Oils” SAE Technical Paper 830027
- Tseregounis, S.I. Viola, M.B. Paranjpe, R.S “Determination of Bearing Oil Film Thickness (BOFT) for Various Engine Oils in an Automotive Gasoline Engine Using Capacitance Measurements and Analytical Predictions” GM, Research and Development Center, Publication RD-8826 1998
- Hutton, J.F. Jones, B. Bates, T.W. “Effect of Isotropic Pressure on the High Temperature High Shear Viscosity of Motor Oils” SAE Technical Paper 830030
- Williamson, B.P. “Enhancement of Journal Load Bearings Capacity by Polymer Containing Oils” SAE Technical Paper 971697
- Moore, A.J. “Influences of Lubricant Properties on ASTM Sequence VI and Sequence VI-A Fuel Efficiency Performance” SAE Technical Paper 961138
- Williamson, B.P. Bell, J.C. “The Effects of Engine Oil Rheology on the Oil Film Thickness and Wear Between a Cam and Rocker Follower” SAE Technical Paper 962031