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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.

Cam-follower mechanisms are extremely important in modern equipment, widely used in automotive engines and machinery that requires complex motion with repeatability and reliability. A cam is a solid body and its shape in conjunction of follower’s type defines a movement that can be too difficult or even impossible to reproduce with others mechanisms. The objective of this analysis is the dynamic study, which is divided into kinematic and kinetics for both flat faced and offset roller follower in translating motion. The kinematics can be studied in focus on the synthesis or on the analysis. Some well-known functions applied to cam-follower pairs are cycloidal, harmonic and polynomial, however the application of classical sixth order spline is an interesting alternative to this type of study. The kinetic study has gained more importance in recent years due to increase of machinery’s speed.

Initial product designs contain some parameters mapped by study and it is extremely important a full model understanding of process. Design of experiments methodology (DOE) shows some approaches for this goal and one of them is factorial design. However, a full factorial design is not recommended for more than four parameters, which would demand lots of testing run and initial budget for development projects is limited. This problem gets worse when it is desired to optimize two contradiction parameters, e. g., light weight and high strength material. This work deals with comparison of some initial design of experiments aiming to improve basic new product or process knowledge by as few as possible runs. It was performed some variations of fractional factorial design and a Plackett-Burman method and compared among them and their impacts in analysis.

In recent years, the concern about pollutants emissions has increased along with as customer requirements for more efficient internal combustion engine (ICE). To satisfy these demands, new technologies have been introduced in ICE, such as smaller engine bearings, a reduction in the number of cylinders, variable displacements, peak cylinder pressure (PCP) increases, among other things. Sliding bearings are responsible for vital function under engine operation and also friction losses, impacting on fuel consumption as well as pollutants emissions. To maximize the bearing’s performance, it is important to guarantee a hydrodynamic regime, in order to reduce wear and avoid power loss due to metal-to-metal friction, and consequently, premature failure of engine components. Material roughness indicates, with oil film, the lubrication regime as boundary, mixed or hydrodynamic.

Nowadays, due to the emissions regulations and customer requirements for more economic vehicles there is a demand of more efficient Internal Combustion Engine (ICE). The hydrodynamic bearings play an important rule converting the piston reciprocating displacement into a rotational motion. Thus, considering the sliding bearings vital to define the engine life and also responsible for part of friction loss inside the engine, it is important to optimize its profile and consequently tribological performance parameters which impact on fuel consumption. All in all, this work shows the analysis between lemon shape big end bearing and cylindrical one, in order to evaluate the advantages and disadvantages related to this micro profile.