Open AccessExperimental detection of mechanical efficiency of marine diesel engines
Author(s) -
Oleg Petrovich Shuraev
Publication year - 2020
Publication title -
vestnik astrahanskogo gosudarstvennogo tehničeskogo universiteta. seriâ: morskaâ tehnika i tehnologiâ
Language(s) - English
Resource type - Journals
eISSN - 2225-0352
pISSN - 2073-1574
DOI - 10.24143/2073-1574-2020-4-69-78
Subject(s) - crankshaft , automotive engineering , diesel engine , mechanical engineering , cylinder , engine power , propeller , power (physics) , computer science , marine engineering , engineering , physics , quantum mechanics
The article summarizes the results of heat engineering tests of diesels used in the educational process of Volga State University of Water Transport and its branches. Although the test goals were different in each case, the indicator diagrams of the working process in each cylinder were recorded in the course of the tests. Analysis of indicator diagrams helped to determine the indicator power of the engine in each case. By comparing the indicator parameters with the corresponding effective ones there was performed the estimation of the mechanical efficiency of each engine at different speeds of rotation of the crankshaft. The studies were carried out on engines of brands 6NVD48AU, 6L275RrII/PN, 8NVD36U, 6L160PNS. It was found that in almost all cases, mechanical losses included fan losses in load devices and friction losses in their bearings. The concept of a screw characteristic is considered. A graph of the propeller characteristics in relative units for various types of engines is built. It is noted that it is very difficult to set a specific value of the crankshaft speed required for testing, the actual points will be close to the theoretical ones, shifting along the helical characteristic. An algorithm for testing and processing the results is presented. There have been analyzed the dependences covered in literature (analytical and statistical) for determining the mechanical efficiency.