ТЕХНОЛОГИЯ ВОССТАНОВЛЕНИЯ БЛОКОВ ЦИЛИНДРОВ С ДЕФЕКТОМ КРЫШКИ КОРЕННОЙ ОПОРЫ И ОЦЕНКА КАЧЕСТВА ИХ РЕМОНТА С ПОМОЩЬЮ СТАТИСТИЧЕСКОЙ МОДЕЛИ НАДЕЖНОСТИ

Abstract

Currently, the reconditioning of engine blocks featuring ‘split joint’ main bearing caps is challenging since there is no basic technology for the rebuilding process. The paper introduces a method for restoring engine blocks with and without the described design feature and discusses the possibility of using a mathematical distribution of the engine life to assess the repair quality. Methods of the mathematical planning theory were used to assess the quality of an overhauled engine. A multifactorial experiment was conducted to obtain experimental data. The overhaul quality properties were analysed to identify indicators and parameters which are critical for assessing the quality of engine repairs. The study established indices of the engine life, namely, the mean life, for assessing the quality of an overhauled engine. For determining the engine reliability, the distribution law of indices for sampling the engine lifetime data was established. Currently, engine blocks featuring ‘split joint’ main bearing caps are not repaired. The technological solution to reconditioning the described engine blocks involves milling the contact surface of the main bearing cap and working it up to exclude lateral displacement during operation. Computations used the reliability index, the mean life between overhauls for assessing the quality of an overhauled engine. The authors came up with a statistical model of the engine life distribution with a confidence coefficient of 91 %.