Measurement of the Journal Locus in the Con-Rod Big-End Bearing of an Automobile Gasoline Engine

Abstract

To measure the absolute oil film thickness or the journal center locus in con-rod big-end bearings of a practical automobile engine, a special new device and procedure have been developed. By means of this method, the measurement could be carried out stably up to full load at 5000 rpm. These measurements revealed that the journal travels along the vicinity of bearing surface by the inertia force. In the combustion period, however, the journal center passes near the center point of the bearing. On the other hand, under a misalignment condition, the minimum oil film thickness depends on the combustion pressure. Therefore in the future many of the problems related to con-rod big-end bearings will be resolved by this method.