Almost immediately after Rudolph Diesel created his "rational" engine, attempts were made to improve it. Since at the end of the nineteenth and the beginning of the twentieth century, the theory of internal combustion engines had not yet been formed as a unified scientific system, there were no unified approaches to assessing the innovations proposed by individual engineers and scientists either. In this regard, disputes and litigations periodically arose related to the recognition of priority for a specific design or the proposed principle of work for a specific author. First of all, this was due to the possibility of obtaining material benefits from the introduction of a patented innovation into production. It should be noted that profit-related litigation and information campaigns were not always objective, and the development of progress at the turn of the century were so rapid that the same ideas entered the heads of several independent inventors at once, but the same discoveries were made in different parts of the world by different scientists. By the beginning of the twentieth century, the accumulated experience, as well as theoretical and experimental studies have shown that it was possible to significantly improve the nature of the flow of the working process of piston engines by replacing the isochoric or isobaric heat supply in the process of fuel combustion with a combined one with heat supply, first at a constant volume (by isochore), and then at constant pressure (isobar). Three scientists - Gustav Trinkler, Myron Zaliger and Louis Gaston Sabathe claimed priority in the development of such a cycle. Each of them came to this decision in different ways, and each made his own contribution both to the formation of the theory of working processes of piston engines, and to the formation of engine building in general. It is to this contribution made by the French engineer Louis Gaston Sabathe that this article is devoted. ; Практически сразу после создания Рудольфом Дизелем своего «рационального» ...