This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
Lubrication and Stress Analyses of the Cam Roller System in a Distributor Fuel Injection Rotary Pump
Annotation ability available
Sector:
Language:
English
Abstract
Design of the pressure pumping mechanism in a distributor fuel injection rotary pump becomes an uneasy task due to the restless demands for raising injection pressure. This paper presents a numerical simulation model developed to analyze the design appropriateness of the cam ring, roller, and shoe components in the pumping mechanism based on their tribological performance. The developed model solves the lubrication of cam/roller and roller/shoe interfaces simultaneously. Lubrication of the cam roller interface is modeled with a mixed lubrication concept to include the surface asperity contact effects. The load-carrying capacity of the surface is characterized by using a contact mechanics model with the measured surface profiles. Assuming the shoe body is rigid, the roller shoe interfacial lubrication is treated as a partial hydrodynamic bearing including the effect at roller slippage. The simulation results indicate that the cam roller film thickness is constantly lower than the surface roughness level. Surface contact stresses are extremely high, since majority of the load is carried by surface asperities. The calculated subsurface stresses indicate that, due to the high surface contact stresses, high stress concentrations are found in the near-surface region within the depth of 10 mm. Hence, the near-surface originated contact fatigue is most likely the dominant failure model for the cam roller interface.
Authors
Citation
Sui, P., "Lubrication and Stress Analyses of the Cam Roller System in a Distributor Fuel Injection Rotary Pump," SAE Technical Paper 970640, 1997, https://doi.org/10.4271/970640.Also In
References
- Djordjevic, I. Harris, A. H. Paradis, C. A. “A New High Pressure Distributor Pump for Mid-Range Diesel Engines” J. of Institution of Mechanical Engineers
- Zaretsky, E. V. “Life Factors for Rolling Bearings” STLE Publications SP-34 1992
- Dyson, A. “Elastohydrodynamic Lubrication and Wear of Cams Bearing Against Cylindrical Tappets” SAE Paper No. 770018
- Sui, Ping C. “An Efficient Computation Model for Calculating Surface Contact Pressures Using Measured Surface Roughness” Tribology Transactions Jan. 1997
- Lee, Rong-Tsong Hamrock, B. J. “Squeeze and Entraining Motion in Nonconformal Line Contacts. Part II--Elastohydrodynamic Lubrication” Transactions of the ASME 111 8 16 Jan. 1989
- Ross, J. M. Slaymaker, R. R. “Journal Center Orbits in Piston Engine Bearings” SAE Paper No. 690114
- Harris, T. N. “Rolling Bearing Analysis,” 2nd John Wiley & Sons 1984
- Ioannides, E. Harris, T. “A New Fatigue Life Model for Rolling Bearings” ASME Journal of Tribology 107 367 378 1985
- Firsov, V. T. Shiryaev A. V. “Prediction of Contact Fatigue Strength of Steels of Various Hardness,” Vestnik Mashinostroeniva 69 5 1989
- Popinceanu, N. G. Diaconescu, E. Cretu, S. “Critical Stresses in Rolling Contact Fatigue” Wear 71 265 282 1981