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This work presents an experimental study to analyze the influence of surface finishing on engine journal bearing performance. Bimetallic bearings were manufactured with two bored finishings, one called conventional and another microprofiled. Microprofiled bearings have a potential advantage due to the higher conformability of these parts under the engine operational conditions. Bench tests and engine test were conducted in order to check the loading carrying capacity (LCC) until seizure occurrence; the temperature was evaluated at the steel back of the tested parts. Surface of the parts was evaluated after the tests. The results showed that microprofiled bearings presented slightly lower temperature at steel back during the bench tests than the conventional bearings. The loading carrying capacity for both parts was similar, due to the relatively low speed test.

The use of Biodiesel is one of the main drivers behind biomass fuels for diesel engine use. This paper compares the performance of powercell components after 100 thousand km field tests using different fuel variants. The tested engine was a 3.0L High Speed Diesel with 120kW @ 3800rpm. Two variants of B5 fuels were tested: one with oil from Soy Bean and other from Castor Bean. Each type of fuel, including regular Diesel, was tested twice. Compared to regular Diesel, the engines tested with B5 presented similar performance [1]. The evaluated powercell parts were: piston, rings, bearings, and cylinder bores. The parts were evaluated in terms of wear, seizure and corrosion. The parts from the B5 tests presented similar visual characteristics after test compared with regular Diesel. A slight wear increase was observed on the parts that ran with the B5 variants. In the case of bearings, corrosion residues were observed with B5 from Castor oil.

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.