Development of Friction Prediction Procedure and Friction Reduction Technologies for New Nissan HR and MR Engines

In developing the new Nissan HR (1.5L Inline-4) and MR (2.0L Inline-4) engines, reducing mechanical friction loss was one of the key elements considered throughout all development phases. In order to achieve the highest target for reducing mechanical friction loss, an improved, more accurate friction prediction procedure was developed. This relative-based friction prediction procedure with approximately 250 points of detailed component analysis was adopted from the beginning of development in order to cope with any specification changes and select the most effective friction reduction measures for the new engines. A description is given of such friction reduction measures adopted in the valvetrain and cranktrain of the new engines. Accuracy of the improved prediction procedure was verified by comparing the predicted results with measurements, which indicated that the procedures provide a reasonable prediction of mechanical friction. As a result of applying various friction reduction measures, the new HR and MR engines achieved friction reduction targets and have the lowest levels of mechanical friction in their class.