DEVELOPMENT OF ENGINE BEARING SOLUTIONS FOR NEW HIGH OUTPUT AUTOMOTIVE ENGINES

With the development of advanced engine technologies, which includes direct injected, turbo-charged, variable valve timed, flex-fuel, hybrid start-stop cycles and a general downsizing of engine architectures, bearing surface areas have decreased and connecting rod loading has increased. As a result, modern bearings experience decreased oil film thickness, more frequent non-hydrodynamic lubrication periods and higher surface sliding speeds. Subsequently, bearing applications demand an increase in fatigue and scuffing resistance. In response to this, two new complementary material developments are documented: one a new aluminum based lining material, the other a polymeric surface layer. The new lining material, called A-650, was developed to have improved fatigue strength relative to existing Al engine bearing lining options. Results for rig testing of fatigue and seizure resistance properties are provided, along with engine test evaluations using multiple fuels. The polymeric surface layer, a polyamideimide based resin called IROX (TM), is intended as a durable surface coating providing exceptional wear and seizure resistance under high sliding speed and start-stop conditions. Furthermore, an increase of the specific load capacity is achieved with aluminum based substrates. A description of the material, with test results, is included.