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Nowadays, due to high demand for more efficient engines, new technologies are coming in order to reduce engine size and pollutants emissions, but on the other hand pushing for additional performance by peak cylinder pressure (PCP) increasing. In this scenario, solutions as engine bearing downsizing, number of cylinder reduction and variable compression rate (VCR) has been provided. One of these new technologies is the bushingless connecting rod pin joint system in which the small end bushing is no longer used and the powercell system is composed by the piston pin assembled directly in the connecting rod small end. To enable this downsize with loads increasing, a technology with special micro-profile and coated for mid-range diesel vehicle application was developed, since there is a technical & cost restrictions of current bushings for upcoming PCP.

Targeting the current demands for engines with lower emissions, reduced fuel consumption, downsizing and higher peak combustion pressures, thyssenkrupp has developed a new cranktrain concept comprising an increased radial transition between journal and web that extends itself into the bearing’s load-carrying zone, creating a symmetrical U-shaped profile. The resulting non-straight bearing contour restricts the use of a standard bearing shell and led to the development of an integral bearing solution, where a copper based material was applied directly to the connecting rod big end bore. The so-called U-shape cranktrain was experimentally evaluated on a fired engine through a series of eight test steps with varied loads and speeds, being each step condition defined in a way that increased severity was applied to the connecting rod bearings as the test proceeded. The engine was disassembled after each step for analysis and measurement of the crankshaft and connecting rods.