A car engine has 5 main crankshaft bearings and runs at a maximum of 6,500 rev min-1at a working temperature of 100 °C. The engine uses an SAE 10W40 grade oil. Other data are given below. From a design point of view, one worst case scenario is a cold start in a mid European winter at -20 °C. Use Petrov's equation to determine the power absorbed by the main bearings at normal running conditions. Then, assuming the engine could be started determine what maximum speed it could run at in the coldest conditions before it warmed up, neglecting all other losses, if the engine could deliver 60 kW of power. Parameters:
- Journal diameter = 46.0 mm
- Bearing axial length = 28.0 mm
- Radial clearance = 0.035 mm
- Oil density (assumed constant) = 890.0 kg m-3