actually
Effect of oil viscosity on hydrodynamic friction of engine bearings
but had to fit it in title bar.
http://www.substech.com/dokuwiki/doku.ph...engine_bearings
Quote:
The parameters of hydrodynamic lubrication of bearings [2] were theoretically calculated using software developed by King Engine Bearings. The software, called ENSIM™, is an advanced engine simulation module. It is capable of calculating the thermodynamic, dynamic, hydrodynamic and mechanical parameters of bearing operation. ENSIM™ is used for designing new bearings and for modifying the bearings of existing engines. For the purposes of this theme paper study, calculations of the parameters of hydrodynamic lubrication were made for high performance King CR 807XPN (connecting rod bearing).
Three oil grades, (0w5, 10W30, 10W60), modelled on one of their con-rod bearings, with 0.0004", 0.002", and 0.004" diametrical clearance, at a number of RPMs.
Calculations of Minimum Oil film thickness, power loss (frictional heating), and importantly, the ratio of pressure distributions across the bearing (easier leakage means peakier pressure profiles, and less even sharing of bearing loads)
Results shouldn't come as any great surprise, but there are quite a few myths perpetrated over the years.
Quote:
Conclusions
* The greater oil viscosity the greater minimum oil film thickness, power loss due friction and uniformity of oil film pressure.
* Effect of oil viscosity on min. oil film thickness, power loss and the Pmax/Pav ratio increases with an increase of bearing clearance.
* For the oil 0W5 the greatest value of oil film thickness is achieved at clearance of 0.0004” (1/5000 of the bearing diameter).
* For the oil 10W30 the greatest value of oil film thickness is achieved at clearance of 0.002” (1/1000 of the bearing diameter).
*For the oil 10W60 the greatest value of oil film thickness is achieved at clearance of 0.004” (1/500 of the bearing diameter).
Effect of oil viscosity on hydrodynamic friction of engine bearings
but had to fit it in title bar.
http://www.substech.com/dokuwiki/doku.ph...engine_bearings
Quote:
The parameters of hydrodynamic lubrication of bearings [2] were theoretically calculated using software developed by King Engine Bearings. The software, called ENSIM™, is an advanced engine simulation module. It is capable of calculating the thermodynamic, dynamic, hydrodynamic and mechanical parameters of bearing operation. ENSIM™ is used for designing new bearings and for modifying the bearings of existing engines. For the purposes of this theme paper study, calculations of the parameters of hydrodynamic lubrication were made for high performance King CR 807XPN (connecting rod bearing).
Three oil grades, (0w5, 10W30, 10W60), modelled on one of their con-rod bearings, with 0.0004", 0.002", and 0.004" diametrical clearance, at a number of RPMs.
Calculations of Minimum Oil film thickness, power loss (frictional heating), and importantly, the ratio of pressure distributions across the bearing (easier leakage means peakier pressure profiles, and less even sharing of bearing loads)
Results shouldn't come as any great surprise, but there are quite a few myths perpetrated over the years.
Quote:
Conclusions
* The greater oil viscosity the greater minimum oil film thickness, power loss due friction and uniformity of oil film pressure.
* Effect of oil viscosity on min. oil film thickness, power loss and the Pmax/Pav ratio increases with an increase of bearing clearance.
* For the oil 0W5 the greatest value of oil film thickness is achieved at clearance of 0.0004” (1/5000 of the bearing diameter).
* For the oil 10W30 the greatest value of oil film thickness is achieved at clearance of 0.002” (1/1000 of the bearing diameter).
*For the oil 10W60 the greatest value of oil film thickness is achieved at clearance of 0.004” (1/500 of the bearing diameter).