The market has recently required the bearings to operate under
intermittent or occasionally boundary lubrication conditions
through requirements guided basically by CO₂ reduction: flex-fueled
engines, stop-start operation, specification of low viscosity oils,
extension of high speed regimes with low stiffness conrods and
crankshafts.
The sensitivity of the oil film rupture, higher loads and the
robustness of operation required the development of low friction
coatings or overlays with improved wear resistance.
MAHLE response to these requirements has been addressed through
a newly developed product assigned as polymer-coated bearing. The
polymeric overlay has a proprietary low friction solid blend and it
is sprayed onto premium bimetallic bearings.
In this paper it is shown that these bearings run at lower
temperature, with lower friction and can support higher loads than
the conventional bimetallic bearing. When submitted to a stop-start
(boundary lubrication) condition presented much less wear than
premium bimetallic bearings.