抄録
This paper firstly describes outline of a new technology for semi-permanent use of engine oil without oil change and without waste oil, as well as some results of its practical use. Secondly, the paper reports that engine wear is remarkably decreased if lubricating oil (LO) and fuel oil (FO), or either of them are kept clean. Lastly, assumption of LO optimum contamination is discussed and field data of nearly no wear of engines are presented.
