Design and Validation of Innovative Bushingless Pin Joint System Technology for Mid-Range Connecting Rod 2016-36-0340

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. Deep experimental validation, through engine tests, confirmed that this innovative design is robust allowing moving forward to serial production. So, not less important than the concept itself, it is its optimization through simulation based on experimental tests and related background. The optimization methodology was also developed and considers the running-in phenomenon, which is already known in engine components, and became a vital parameter to increase the robustness to different emission regulations. This optimized profile will guarantee that not only during the break-in condition the engine will have better performance, but also during all engine cycle under field operation presenting lower asperity pressure, optimum oil film thickness and related lower power loss.